bims-cagime Biomed News
on Cancer, aging and metabolism
Issue of 2020‒10‒18
83 papers selected by
Kıvanç Görgülü
Technical University of Munich

  1. J Cell Biol. 2020 Dec 07. pii: e202001165. [Epub ahead of print]219(12):
    Lord CL, Wente SR.
      The intricacy of nuclear pore complex (NPC) biogenesis imposes risks of failure that can cause defects in nuclear transport and nuclear envelope (NE) morphology; however, cellular mechanisms used to alleviate NPC assembly stress are not well defined. In the budding yeast Saccharomyces cerevisiae, we demonstrate that NVJ1- and MDM1-enriched NE-vacuole contacts increase when NPC assembly is compromised in several nup mutants, including nup116ΔGLFG cells. These interorganelle nucleus-vacuole junctions (NVJs) cooperate with lipid droplets to maintain viability and enhance NPC formation in assembly mutants. Additionally, NVJs function with ATG1 to remodel the NE and promote vacuole-dependent degradation of specific nucleoporins in nup116ΔGLFG cells. Importantly, NVJs significantly improve the physiology of NPC assembly mutants, despite having only negligible effects when NPC biogenesis is unperturbed. These results therefore define how NE-vacuole interorganelle contacts coordinate responses to mitigate deleterious cellular effects caused by disrupted NPC assembly.
  2. Elife. 2020 Oct 14. pii: e55578. [Epub ahead of print]9
    Singhal NS, Bai M, Lee EM, Luo S, Cook KR, Ma DK.
      Many organisms in nature have evolved mechanisms to tolerate severe hypoxia or ischemia, including the hibernation-capable Arctic ground squirrel (AGS). Although hypoxic or ischemia tolerance in AGS involves physiological adaptations, little is known about the critical cellular mechanisms underlying intrinsic AGS cell resilience to metabolic stress. Through cell survival-based cDNA expression screens in neural progenitor cells, we identify a genetic variant of AGS Atp5g1 that confers cell resilience to metabolic stress. Atp5g1 encodes a subunit of the mitochondrial ATP synthase. Ectopic expression in mouse cells and CRISPR/Cas9 base editing of endogenous AGS loci revealed causal roles of one AGS-specific amino acid substitution in mediating cytoprotection by AGS ATP5G1. AGS ATP5G1 promotes metabolic stress resilience by modulating mitochondrial morphological change and metabolic functions. Our results identify a naturally occurring variant of ATP5G1 from a mammalian hibernator that critically contributes to intrinsic cytoprotection against metabolic stress.
    Keywords:  cell biology; genetics; genomics
  3. Diabetes. 2020 Oct 12. pii: db190762. [Epub ahead of print]
    Song E, Da Eira D, Jani S, Sepa-Kishi D, Vu V, Hunter H, Lai M, Wheeler MB, Ceddia RB, Sweeney G.
      Increased myocardial autophagy has been established as an important stress-induced cardioprotective response. Three weeks after generating cardiomyocyte-specific autophagy deficiency, via inducible deletion of autophagy related protein 7 (Atg7), we found these mice (AKO) increased body weight and fat mass without altered food intake. Glucose and insulin tolerance tests indicated reduced insulin sensitivity in AKO mice. Metabolic cage analysis showed reduced ambulatory activity and oxygen consumption with a trend of elevated respiratory exchange ratio in AKO mice. Direct analysis of metabolism in subcutaneous and visceral adipocytes showed increased glucose oxidation and reduced ATGL expression and HSL phosphorylation with no change in lipid synthesis or fatty acid oxidation. Importantly, we found AKO mice had reduced myocardial and circulating levels of atrial natriuretic peptide (ANP), an established mediator of myocardial-adipose crosstalk. When normal ANP levels were restored to AKO mice using osmotic pump, the metabolic dysfunction evident in AKO mice was corrected. We conclude that cardiac autophagy deficiency alters myocardial-adipose crosstalk via decreased ANP levels with adverse metabolic consequences.
  4. J Biol Chem. 2020 10 15. pii: jbc.REV120.015101. [Epub ahead of print]
    Prole DL, Chinnery PF, Jones NS.
      Mitochondrial DNA (mtDNA) encodes proteins and RNAs that support the functions of mitochondria and thereby numerous physiological processes. Mutations of mtDNA can cause mitochondrial diseases and are implicated in ageing. The mtDNA within cells is organized into nucleoids within the mitochondrial matrix, but how mtDNA nucleoids are formed and regulated within cells remains incompletely resolved. Visualization of mtDNA within cells is a powerful means by which mechanistic insight can be gained. Manipulation of the amount, and sequence of, mtDNA within cells is important experimentally and for developing therapeutic interventions to treat mitochondrial disease. This review details recent developments and opportunities for improvements in the experimental tools and techniques that can be used to visualize, quantify and manipulate the properties of mtDNA within cells.
    Keywords:  aging; gene editing; microscopy; mitochondria; mitochondrial DNA (mtDNA); mitochondrial disease; mitophagy
  5. Proc Natl Acad Sci U S A. 2020 Oct 14. pii: 202009943. [Epub ahead of print]
    Leu JI, Murphy ME, George DL.
      The p53 tumor suppressor protein is a transcription factor and master stress response mediator, and it is subject to reduction-oxidation (redox)-dependent regulation. The P47S variant of TP53, which exists primarily in African-descent populations, associates with an elevated abundance of low molecular weight (LMW) thiols, including glutathione (GSH) and coenzyme A (CoA). Here we show that S47 and P47 cells exhibit distinct metabolic profiles, controlled by their different redox states and expression of Activating Transcription Factor-4 (ATF4). We find that S47 cells exhibit decreased catabolic glycolysis but increased use of the pentose phosphate pathway (PPP), and an enhanced abundance of the antioxidant, NADPH. We identify ATF4 as differentially expressed in P47 and S47 cells and show that ATF4 can reverse the redox status and rescue metabolism of S47 cells, as well as increase sensitivity to ferroptosis. This adaptive metabolic switch is rapid, reversible, and accompanied by thiol-mediated changes in the structures and activities of key glycolytic signaling pathway proteins, including GAPDH and G6PD. The results presented here unveil the important functional interplay among pathways regulating thiol-redox status, metabolic adaptation, and cellular responses to oxidative stress.
    Keywords:  ATF4; coenzyme A; cysteine modifications; ferroptosis; p53
  6. Nat Commun. 2020 10 14. 11(1): 5167
    Donau C, Späth F, Sosson M, Kriebisch BAK, Schnitter F, Tena-Solsona M, Kang HS, Salibi E, Sattler M, Mutschler H, Boekhoven J.
      Membraneless organelles like stress granules are active liquid-liquid phase-separated droplets that are involved in many intracellular processes. Their active and dynamic behavior is often regulated by ATP-dependent reactions. However, how exactly membraneless organelles control their dynamic composition remains poorly understood. Herein, we present a model for membraneless organelles based on RNA-containing active coacervate droplets regulated by a fuel-driven reaction cycle. These droplets emerge when fuel is present, but decay without. Moreover, we find these droplets can transiently up-concentrate functional RNA which remains in its active folded state inside the droplets. Finally, we show that in their pathway towards decay, these droplets break apart in multiple droplet fragments. Emergence, decay, rapid exchange of building blocks, and functionality are all hallmarks of membrane-less organelles, and we believe that our work could be powerful as a model to study such organelles.
  7. Nat Rev Endocrinol. 2020 Oct 16.
    Nikolic I, Leiva M, Sabio G.
      Obesity is a health condition that has reached pandemic levels and is implicated in the development and progression of type 2 diabetes mellitus, cancer and heart failure. A key characteristic of obesity is the activation of stress-activated protein kinases (SAPKs), such as the p38 and JNK stress kinases, in several organs, including adipose tissue, liver, skeletal muscle, immune organs and the central nervous system. The correct timing, intensity and duration of SAPK activation contributes to cellular metabolic adaptation. By contrast, uncontrolled SAPK activation has been proposed to contribute to the complications of obesity. The stress kinase signalling pathways have therefore been identified as potential targets for the development of novel therapeutic approaches for metabolic syndrome. The past few decades have seen intense research efforts to determine how these kinases are regulated in a cell-specific manner and to define their contribution to the development of obesity and insulin resistance. Several studies have uncovered new and unexpected functions of the non-classical members of both pathways. Here, we provide an overview of the role of SAPKs in metabolic control and highlight important discoveries in the field.
  8. J Thromb Haemost. 2020 Oct 16.
    Schweickert PG, Yang Y, White EE, Cresswell GM, Elzey BD, Ratliff TL, Arumugam P, Antoniak S, Mackman N, Flick MJ, Konieczny SF.
      BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is characterized by a prothrombotic state and a lack of host anti-tumor immune responsiveness. Linking these two key features, we previously demonstrated that tumor-derived coagulation activity promotes immune evasion. Specifically, thrombin-protease-activated receptor-1 (PAR1) signaling in mouse PDAC cells drives tumor growth by evading cytotoxic CD8a+ cells.METHODS: Syngeneic mixed cell tumor growth, transcriptional analyses, and functional tests of immunosuppressive response genes were employed to identify cellular and molecular immune evasion mechanisms mediated by thrombin-PAR-1 signaling in mouse PDAC tumor cells.
    RESULTS: Elimination of tumor cell PAR1 in syngeneic graft studies increased cytotoxic T lymphocyte (CTL) infiltration and decreased tumor-associated macrophages in the tumor microenvironment. Co-injection of PAR1-expressing and PAR1-knockout (PAR-1KO ) tumor cells into immunocompetent mice resulted in preferential elimination of PAR-1KO cells from developing tumors, suggesting that PAR1-dependent immune evasion is not reliant on CTL exclusion. Transcriptomics analyses revealed no PAR1-dependent changes in the expression of immune checkpoint proteins and no difference in MHC-I cell surface expression. Importantly, thrombin-PAR1 signaling in PDAC cells upregulated genes linked to immunosuppression, including Csf2 and Ptgs2. Functional analyses confirmed that both Csf2 and Ptgs2 are critical for PDAC syngeneic graft tumor growth and overexpression of each factor partially restored tumor growth of PAR1KO cells in immunocompetent mice.
    CONCLUSIONS: Our results provide novel insight into the mechanisms of a previously unrecognized pathway coupling coagulation to PDAC immune evasion by identifying PAR1-dependent changes in the tumor microenvironment, a PAR1-driven immunosuppressive gene signature, and Csf2 and Ptgs2 as critical PAR1 downstream targets.
    Keywords:  cancer; cytotoxic T lymphocyte; immune evasion; immunosuppression; pancreatic ductal adenocarcinoma; protease activated receptor 1; thrombin
  9. Mol Cell. 2020 Oct 08. pii: S1097-2765(20)30681-X. [Epub ahead of print]
    Wang L, Wu D, Robinson CV, Wu H, Fu TM.
      Vesicular- or vacuolar-type adenosine triphosphatases (V-ATPases) are ATP-driven proton pumps comprised of a cytoplasmic V1 complex for ATP hydrolysis and a membrane-embedded Vo complex for proton transfer. They play important roles in acidification of intracellular vesicles, organelles, and the extracellular milieu in eukaryotes. Here, we report cryoelectron microscopy structures of human V-ATPase in three rotational states at up to 2.9-Å resolution. Aided by mass spectrometry, we build all known protein subunits with associated N-linked glycans and identify glycolipids and phospholipids in the Vo complex. We define ATP6AP1 as a structural hub for Vo complex assembly because it connects to multiple Vo subunits and phospholipids in the c-ring. The glycolipids and the glycosylated Vo subunits form a luminal glycan coat critical for V-ATPase folding, localization, and stability. This study identifies mechanisms of V-ATPase assembly and biogenesis that rely on the integrated roles of ATP6AP1, glycans, and lipids.
  10. Science. 2020 Oct 16. pii: eaay8085. [Epub ahead of print]370(6514):
    Bosch M, Sánchez-Álvarez M, Fajardo A, Kapetanovic R, Steiner B, Dutra F, Moreira L, López JA, Campo R, Marí M, Morales-Paytuví F, Tort O, Gubern A, Templin RM, Curson JEB, Martel N, Català C, Lozano F, Tebar F, Enrich C, Vázquez J, Del Pozo MA, Sweet MJ, Bozza PT, Gross SP, Parton RG, Pol A.
      Lipid droplets (LDs) are the major lipid storage organelles of eukaryotic cells and a source of nutrients for intracellular pathogens. We demonstrate that mammalian LDs are endowed with a protein-mediated antimicrobial capacity, which is up-regulated by danger signals. In response to lipopolysaccharide (LPS), multiple host defense proteins, including interferon-inducible guanosine triphosphatases and the antimicrobial cathelicidin, assemble into complex clusters on LDs. LPS additionally promotes the physical and functional uncoupling of LDs from mitochondria, reducing fatty acid metabolism while increasing LD-bacterial contacts. Thus, LDs actively participate in mammalian innate immunity at two levels: They are both cell-autonomous organelles that organize and use immune proteins to kill intracellular pathogens as well as central players in the local and systemic metabolic adaptation to infection.
  11. Cell. 2020 Oct 14. pii: S0092-8674(20)31241-1. [Epub ahead of print]
    Kim D, Xue JY, Lito P.
      KRAS mutations are among the most common genetic alterations in lung, colorectal, and pancreatic cancers. Direct inhibition of KRAS oncoproteins has been a long-standing pursuit in precision oncology, one established shortly after the discovery of RAS mutations in human cancer cells nearly 40 years ago. Recent advances in medicinal chemistry have established inhibitors targeting KRAS(G12C), a mutation found in ∼13% of lung adenocarcinomas and, at a lower frequency, in other cancers. Preclinical studies describing their discovery and mechanism of action, coupled with emerging clinical data from patients treated with these drugs, have sparked a renewed enthusiasm in the study of KRAS and its therapeutic potential. Here, we discuss how these advances are reshaping the fundamental aspects of KRAS oncoprotein biology and the strides being made toward improving patient outcomes in the clinic.
  12. EMBO Rep. 2020 Oct 12. e50085
    Wang Z, Ning T, Song A, Rutter J, Wang QA, Jiang L.
      The cultured brown adipocytes can oxidize glucose in vitro, but it is still not fully clear whether brown adipose tissue (BAT) could completely oxidize glucose in vivo. Although positron emission tomography (PET) with 18 F-fluorodeoxyglucose (18 F-FDG) showed a high level of glucose uptake in the activated BAT, the non-metabolizable 18 F-FDG cannot fully demonstrate intracellular glucose metabolism. Through in vivo [U-13 C]glucose tracing, here we show that chronic cold exposure dramatically activates glucose oxidation in BAT and the browning/beiging subcutaneous white adipose tissue (sWAT). Specifically, chronic cold exposure enhances glucose flux into the mitochondrial TCA cycle. Metabolic flux analysis models that β3-adrenergic receptor (β3-AR) agonist significantly enhances the flux of mitochondrial pyruvate uptake through mitochondrial pyruvate carrier (MPC) in the differentiated primary brown adipocytes. Furthermore, in vivo MPC inhibition blocks cold-induced glucose oxidation and impairs body temperature maintenance in mice. Together, mitochondrial pyruvate uptake and oxidation serve an important energy source in the chronic cold exposure activated BAT and beige adipose tissue, which supports a role for glucose oxidation in brown fat thermogenesis.
    Keywords:  BAT; in vivo glucose tracing; metabolic flux analysis; mitochondrial pyruvate carrier
  13. J Biol Chem. 2020 Oct 15. pii: jbc.RA120.014831. [Epub ahead of print]
    Kim JH, Seo Y, Jo M, Jeon H, Kim YS, Kim EJ, Seo D, Lee WH, Kim SR, Yachie N, Zhong Q, Vidal M, Roth FP, Suk K.
      Kinases are critical components of intracellular signaling pathways and have been extensively investigated in regards to their roles in cancer. p21-activated kinase-1 (PAK1) is a serine/threonine kinase that has been previously implicated in numerous biological processes, such as cell migration, cell cycle progression, cell motility, invasion, and angiogenesis, in glioma and other cancers. However, the signaling network linked to PAK1 is not fully defined. We previously reported a large-scale yeast genetic interaction screen using toxicity as a readout to identify candidate PAK1 genetic interactions. En masse transformation of the PAK1 gene into 4,653 homozygous diploid S. cerevisiae yeast deletion mutants identified approximately 400 candidates that suppressed yeast toxicity. Here we selected 19 candidate PAK1 genetic interactions that had human orthologs and were expressed in glioma for further examination in mammalian cells, brain slice cultures, and orthotopic glioma models. RNAi and pharmacological inhibition of potential PAK1 interactors confirmed that DPP4, KIF11, mTOR, PKM2, SGPP1, TTK, and YWHAE regulate PAK1-induced cell migration, and revealed the importance of genes related to the mitotic spindle, proteolysis, autophagy, and metabolism in PAK1-mediated glioma cell migration, drug resistance, and proliferation. AKT1 was further identified as a downstream mediator of the PAK1-TTK genetic interaction. Taken together, these data provide a global view of PAK1-mediated signal transduction pathways and point to potential new drug targets for glioma therapy.
    Keywords:  PAK1; cell migration; cell proliferation; drug resistance; genetic interaction; glioma; kinase; molecular cell biology; signal transduction
  14. J Cell Biol. 2020 Nov 02. pii: e202006178. [Epub ahead of print]219(11):
    Albacete-Albacete L, Navarro-Lérida I, López JA, Martín-Padura I, Astudillo AM, Ferrarini A, Van-Der-Heyden M, Balsinde J, Orend G, Vázquez J, Del Pozo MÁ.
      The composition and physical properties of the extracellular matrix (ECM) critically influence tumor progression, but the molecular mechanisms underlying ECM layering are poorly understood. Tumor-stroma interaction critically depends on cell communication mediated by exosomes, small vesicles generated within multivesicular bodies (MVBs). We show that caveolin-1 (Cav1) centrally regulates exosome biogenesis and exosomal protein cargo sorting through the control of cholesterol content at the endosomal compartment/MVBs. Quantitative proteomics profiling revealed that Cav1 is required for exosomal sorting of ECM protein cargo subsets, including Tenascin-C (TnC), and for fibroblast-derived exosomes to efficiently deposit ECM and promote tumor invasion. Cav1-driven exosomal ECM deposition not only promotes local stromal remodeling but also the generation of distant ECM-enriched stromal niches in vivo. Cav1 acts as a cholesterol rheostat in MVBs, determining sorting of ECM components into specific exosome pools and thus ECM deposition. This supports a model by which Cav1 is a central regulatory hub for tumor-stroma interactions through a novel exosome-dependent ECM deposition mechanism.
  15. Nat Metab. 2020 Oct 12.
    Boon R, Silveira GG, Mostoslavsky R.
      Cellular metabolism has emerged as a major biological node governing cellular behaviour. Metabolic pathways fuel cellular energy needs, providing basic chemical molecules to sustain cellular homeostasis, proliferation and function. Changes in nutrient consumption or availability therefore can result in complete reprogramming of cellular metabolism towards stabilizing core metabolite pools, such as ATP, S-adenosyl methionine, acetyl-CoA, NAD/NADP and α-ketoglutarate. Because these metabolites underlie a variety of essential metabolic reactions, metabolism has evolved to operate in separate subcellular compartments through diversification of metabolic enzyme complexes, oscillating metabolic activity and physical separation of metabolite pools. Given that these same core metabolites are also consumed by chromatin modifiers in the establishment of epigenetic signatures, metabolite consumption on and release from chromatin directly influence cellular metabolism and gene expression. In this Review, we highlight recent studies describing the mechanisms determining nuclear metabolism and governing the redistribution of metabolites between the nuclear and non-nuclear compartments.
  16. Nature. 2020 Oct 14.
    Pool AH, Wang T, Stafford DA, Chance RK, Lee S, Ngai J, Oka Y.
      Fluid intake is an essential innate behaviour that is mainly caused by two distinct types of thirst1-3. Increased blood osmolality induces osmotic thirst that drives animals to consume pure water. Conversely, the loss of body fluid induces hypovolaemic thirst, in which animals seek both water and minerals (salts) to recover blood volume. Circumventricular organs in the lamina terminalis are critical sites for sensing both types of thirst-inducing stimulus4-6. However, how different thirst modalities are encoded in the brain remains unknown. Here we employed stimulus-to-cell-type mapping using single-cell RNA sequencing to identify the cellular substrates that underlie distinct types of thirst. These studies revealed diverse types of excitatory and inhibitory neuron in each circumventricular organ structure. We show that unique combinations of these neuron types are activated under osmotic and hypovolaemic stresses. These results elucidate the cellular logic that underlies distinct thirst modalities. Furthermore, optogenetic gain of function in thirst-modality-specific cell types recapitulated water-specific and non-specific fluid appetite caused by the two distinct dipsogenic stimuli. Together, these results show that thirst is a multimodal physiological state, and that different thirst states are mediated by specific neuron types in the mammalian brain.
  17. Science. 2020 Oct 16. 370(6514): 351-356
    Hesketh GG, Papazotos F, Pawling J, Rajendran D, Knight JDR, Martinez S, Taipale M, Schramek D, Dennis JW, Gingras AC.
      The mechanistic target of rapamycin complex 1 (mTORC1) couples nutrient sufficiency to cell growth. mTORC1 is activated by exogenously acquired amino acids sensed through the GATOR-Rag guanosine triphosphatase (GTPase) pathway, or by amino acids derived through lysosomal degradation of protein by a poorly defined mechanism. Here, we revealed that amino acids derived from the degradation of protein (acquired through oncogenic Ras-driven macropinocytosis) activate mTORC1 by a Rag GTPase-independent mechanism. mTORC1 stimulation through this pathway required the HOPS complex and was negatively regulated by activation of the GATOR-Rag GTPase pathway. Therefore, distinct but functionally coordinated pathways control mTORC1 activity on late endocytic organelles in response to distinct sources of amino acids.
  18. Proc Natl Acad Sci U S A. 2020 Oct 16. pii: 202006076. [Epub ahead of print]
    Jain SU, Khazaei S, Marchione DM, Lundgren SM, Wang X, Weinberg DN, Deshmukh S, Juretic N, Lu C, Allis CD, Garcia BA, Jabado N, Lewis PW.
      A high percentage of pediatric gliomas and bone tumors reportedly harbor missense mutations at glycine 34 in genes encoding histone variant H3.3. We find that these H3.3 G34 mutations directly alter the enhancer chromatin landscape of mesenchymal stem cells by impeding methylation at lysine 36 on histone H3 (H3K36) by SETD2, but not by the NSD1/2 enzymes. The reduction of H3K36 methylation by G34 mutations promotes an aberrant gain of PRC2-mediated H3K27me2/3 and loss of H3K27ac at active enhancers containing SETD2 activity. This altered histone modification profile promotes a unique gene expression profile that supports enhanced tumor development in vivo. Our findings are mirrored in G34W-containing giant cell tumors of bone where patient-derived stromal cells exhibit gene expression profiles associated with early osteoblastic differentiation. Overall, we demonstrate that H3.3 G34 oncohistones selectively promote PRC2 activity by interfering with SETD2-mediated H3K36 methylation. We propose that PRC2-mediated silencing of enhancers involved in cell differentiation represents a potential mechanism by which H3.3 G34 mutations drive these tumors.
    Keywords:  H3.3 G34 mutations; NSD1/2; PRC2; SETD2; oncohistones
  19. Am J Cancer Res. 2020 ;10(9): 2851-2864
    Ren D, Qin G, Zhao J, Sun Y, Zhang B, Li D, Wang B, Jin X, Wu H.
      The anti-diabetes drug metformin has emerged as a promising antitumor agent in pancreatic ductal adenocarcinoma (PDAC) among other cancers by promoting the infiltration of immune cells in the tumor microenvironment (TME). However, the mechanisms underlying the antitumor effects of metformin in PDAC remain unclear. In this study, we revealed that metformin induced stimulator of interferon genes (STING) expression in pancreatic cancer cells in a dose- and time-dependent manner. Metformin also activated the STING/IRF3/IFN-β pathway by inhibiting AKT signaling in PDAC cells. Importantly, the combination of metformin with the STING agonist 2'3'-cGAMP exerted synergistic effects in activating the STING/IRF3/IFN-β pathway in pancreatic cancer cells. Additionally, metformin augmented the antitumor effects of 2'3'-cGAMP in mouse models by enhancing the infiltration of T cells in the TME. These findings unveiled a previously unknown mechanism contributing to the antitumor effects of metformin in PDAC, and provide a rationale for its use in combination with existing or novel immunotherapies.
    Keywords:  AKT pathway; Metformin; PDAC; STING
  20. Elife. 2020 Oct 16. pii: e61886. [Epub ahead of print]9
    Le HH, Wrobel CJ, Cohen SM, Yu J, Park H, Helf MJ, Curtis BJ, Kruempel JC, Rodrigues PR, Hu PJ, Sternberg PW, Schroeder FC.
      Signaling molecules derived from attachment of diverse metabolic building blocks to ascarosides play a central role in the life history of C. elegans and other nematodes; however, many aspects of their biogenesis remain unclear. Using comparative metabolomics, we show that a pathway mediating formation of intestinal lysosome-related organelles (LROs) is required for biosynthesis of most modular ascarosides as well as previously undescribed modular glucosides. Similar to modular ascarosides, the modular glucosides are derived from highly selective assembly of moieties from nucleoside, amino acid, neurotransmitter, and lipid metabolism, suggesting that modular glucosides, like the ascarosides, may serve signaling functions. We further show that carboxylesterases that localize to intestinal organelles are required for the assembly of both modular ascarosides and glucosides via ester and amide linkages. Further exploration of LRO function and carboxylesterase homologs in C. elegans and other animals may reveal additional new compound families and signaling paradigms.
    Keywords:  C. elegans; biochemistry; chemical biology
  21. Metabolism. 2020 Oct 13. pii: S0026-0495(20)30260-2. [Epub ahead of print] 154396
    Okamatsu-Ogura Y, Kuroda M, Tsutsumi R, Tsubota A, Saito M, Kimura K, Sakaue H.
      BACKGROUND: Brown adipose tissue (BAT) is a site of metabolic thermogenesis mediated by mitochondrial uncoupling protein 1 (UCP1) and represents a target for a therapeutic intervention in obesity. Cold exposure activates UCP1-mediated thermogenesis in BAT and causes drastic changes in glucose, lipid, and amino acid metabolism; however, the relationship between these metabolic changes and UCP1-mediated thermogenesis is not fully understood.METHODS: We conducted metabolomic and GeneChip array analyses of BAT after 4-h exposure to cold temperature (10 °C) in wild-type (WT) and UCP1-KO mice.
    RESULTS: Cold exposure largely increased metabolites of the glycolysis pathway and lactic acid levels in WT, but not in UCP1-KO, mice, indicating that aerobic glycolysis is enhanced as a consequence of UCP1-mediated thermogenesis. GeneChip array analysis of BAT revealed that there were 2865 genes upregulated by cold exposure in WT mice, and 838 of these were upregulated and 74 were downregulated in UCP1-KO mice. Pathway analysis revealed the enrichment of genes involved in fatty acid (FA) beta oxidation and triglyceride (TG) synthesis in both WT and UCP1-KO mice, suggesting that these metabolic pathways were enhanced by cold exposure independently of UCP1-mediated thermogenesis. FA and cholesterol biosynthesis pathways were enhanced only in UCP1-KO mice. Cold exposure also significantly increased the BAT content of proline, tryptophan, and phenylalanine amino acids in both WT and UCP1-KO mice. In WT mice, cold exposure significantly increased glutamine content and enhanced the expression of genes related to glutamine metabolism. Surprisingly, aspartate was almost completely depleted after cold exposure in UCP1-KO mice. Gene expression analysis suggested that aspartate was actively utilized after cold exposure both in WT and UCP1-KO mice, but it was replenished from intracellular N-acetyl-aspartate in WT mice.
    CONCLUSIONS: These results revealed that cold exposure induces UCP1-mediated thermogenesis-dependent glucose utilization and UCP1-independent active lipid metabolism in BAT. In addition, cold exposure largely affects amino acid metabolism in BAT, especially UCP1-dependently enhances glutamine utilization. These results contribute a comprehensive understanding of UCP1-mediated thermogenesis-dependent and thermogenesis-independent metabolism in BAT.
    Keywords:  Brown adipose tissue; Cold exposure; GeneChip array; Metabolomics; Uncoupling protein 1
  22. Mod Pathol. 2020 Oct 12.
    Janssen BV, Tutucu F, van Roessel S, Adsay V, Basturk O, Campbell F, Doglioni C, Esposito I, Feakins R, Fukushima N, Gill AJ, Hruban RH, Kaplan J, Koerkamp BG, Hong SM, Krasinskas A, Luchini C, Offerhaus J, Sarasqueta AF, Shi C, Singhi A, Stoop TF, Soer EC, Thompson E, van Tienhoven G, Velthuysen MF, Wilmink JW, Besselink MG, Brosens LAA, Wang H, Verbeke CS, Verheij J, .
      Histopathologically scoring the response of pancreatic ductal adenocarcinoma (PDAC) to neoadjuvant treatment can guide the selection of adjuvant therapy and improve prognostic stratification. However, several tumor response scoring (TRS) systems exist, and consensus is lacking as to which system represents best practice. An international consensus meeting on TRS took place in November 2019 in Amsterdam, The Netherlands. Here, we provide an overview of the outcomes and consensus statements that originated from this meeting. Consensus (≥80% agreement) was reached on a total of seven statements: (1) TRS is important because it provides information about the effect of neoadjuvant treatment that is not provided by other histopathology-based descriptors. (2) TRS for resected PDAC following neoadjuvant therapy should assess residual (viable) tumor burden instead of tumor regression. (3) The CAP scoring system is considered the most adequate scoring system to date because it is based on the presence and amount of residual cancer cells instead of tumor regression. (4) The defining criteria of the categories in the CAP scoring system should be improved by replacing subjective terms including "minimal" or "extensive" with objective criteria to evaluate the extent of viable tumor. (5) The improved, consensus-based system should be validated retrospectively and prospectively. (6) Prospective studies should determine the extent of tissue sampling that is required to ensure adequate assessment of the residual cancer burden, taking into account the heterogeneity of tumor response. (7) In future scientific publications, the extent of tissue sampling should be described in detail in the "Materials and methods" section.
  23. Aging Cell. 2020 Oct 13. e13166
    Moore TM, Zhou Z, Strumwasser AR, Cohn W, Lin AJ, Cory K, Whitney K, Ho T, Ho T, Lee JL, Rucker DH, Hoang AN, Widjaja K, Abrishami AD, Charugundla S, Stiles L, Whitelegge JP, Turcotte LP, Wanagat J, Hevener AL.
      Mitochondrial dysfunction is frequently associated with impairment in metabolic homeostasis and insulin action, and is thought to underlie cellular aging. However, it is unclear whether mitochondrial dysfunction is a cause or consequence of insulin resistance in humans. To determine the impact of intrinsic mitochondrial dysfunction on metabolism and insulin action, we performed comprehensive metabolic phenotyping of the polymerase gamma (PolG) D257A "mutator" mouse, a model known to accumulate supraphysiological mitochondrial DNA (mtDNA) point mutations. We utilized the heterozygous PolG mutator mouse (PolG+/mut ) because it accumulates mtDNA point mutations ~ 500-fold > wild-type mice (WT), but fails to develop an overt progeria phenotype, unlike PolGmut/mut animals. To determine whether mtDNA point mutations induce metabolic dysfunction, we examined male PolG+/mut mice at 6 and 12 months of age during normal chow feeding, after 24-hr starvation, and following high-fat diet (HFD) feeding. No marked differences were observed in glucose homeostasis, adiposity, protein/gene markers of metabolism, or oxygen consumption in muscle between WT and PolG+/mut mice during any of the conditions or ages studied. However, proteomic analyses performed on isolated mitochondria from 12-month-old PolG+/mut mouse muscle revealed alterations in the expression of mitochondrial ribosomal proteins, electron transport chain components, and oxidative stress-related factors compared with WT. These findings suggest that mtDNA point mutations at levels observed in mammalian aging are insufficient to disrupt metabolic homeostasis and insulin action in male mice.
    Keywords:  POLG; aging; insulin resistance; metabolism; mitochondria; mitochondrial DNA; obesity
  24. Nat Commun. 2020 Oct 16. 11(1): 5265
    Valle S, Alcalá S, Martin-Hijano L, Cabezas-Sáinz P, Navarro D, Muñoz ER, Yuste L, Tiwary K, Walter K, Ruiz-Cañas L, Alonso-Nocelo M, Rubiolo JA, González-Arnay E, Heeschen C, Garcia-Bermejo L, Hermann PC, Sánchez L, Sancho P, Fernández-Moreno MÁ, Sainz B.
      Pancreatic ductal adenocarcinoma (PDAC), the fourth leading cause of cancer death, has a 5-year survival rate of approximately 7-9%. The ineffectiveness of anti-PDAC therapies is believed to be due to the existence of a subpopulation of tumor cells known as cancer stem cells (CSCs), which are functionally plastic, and have exclusive tumorigenic, chemoresistant and metastatic capacities. Herein, we describe a 2D in vitro system for long-term enrichment of pancreatic CSCs that is amenable to biological and CSC-specific studies. By changing the carbon source from glucose to galactose in vitro, we force PDAC cells to utilize OXPHOS, resulting in enrichment of CSCs defined by increased CSC biomarker and pluripotency gene expression, greater tumorigenic potential, induced but reversible quiescence, increased OXPHOS activity, enhanced invasiveness, and upregulated immune evasion properties. This CSC enrichment method can facilitate the discovery of new CSC-specific hallmarks for future development into targets for PDAC-based therapies.
  25. Clin Cancer Res. 2020 Oct 12. pii: clincanres.2298.2020. [Epub ahead of print]
    Ogawa Y, Masugi Y, Abe T, Yamazaki K, Ueno A, Fujii-Nishimura Y, Hori S, Yagi H, Abe Y, Kitago M, Sakamoto M.
      PURPOSE: Cancer-associated fibroblasts have emerged to be highly heterogenous and can play multifaced roles in dictating pancreatic ductal adenocarcinoma (PDAC) progression, immunosuppression and therapeutic response, highlighting the need for a deeper understanding of stromal heterogeneity between patients and even within a single tumor. We hypothesized that image analysis of fibroblast subpopulations and collagen in PDAC tissues might guide stroma-based patient stratification to predict clinical outcomes and tumor characteristics.EXPERIMENTAL DESIGN: A novel multiplex immunohistochemistry-based image analysis system was established to digitally differentiate fibroblast subpopulations. Using whole-tissue slides from 215 treatment-naïve PDACs, we performed concurrent quantification of principal fibroblast subpopulations and collagen and defined three stroma types: collagen-rich stroma, fibroblast activation protein a (FAP)-dominant fibroblast-rich stroma and a smooth muscle actin (ACTA2)-dominant fibroblast-rich stroma. These stroma types were assessed for the associations with cancer-specific survival by multivariable Cox regression analyses, and with clinicopathological factors including CD8+ cell density.
    RESULTS: FAP-dominant fibroblasts and ACTA2-dominant fibroblasts represented the principal distinct fibroblast subpopulations in tumor stroma. Stroma types were associated with patient survival, SMAD4 status and transcriptome signatures. Compared with FAP-dominant fibroblast-rich stroma, collagen-rich stroma correlated with prolonged survival (HR, 0.57; 95% CI, 0.33-0.99), while ACTA2-dominant fibroblast-rich stroma exhibited poorer prognosis (HR, 1.65; 95% CI, 1.06-2.58). FAP-dominant fibroblast-rich stroma was additionally characterized by restricted CD8+-cell infiltrates and intense neutrophil infiltration.
    CONCLUSIONS: This study identified three distinct stroma types differentially associated with survival, immunity and molecular features, thereby underscoring the importance of stromal heterogeneity in subtyping pancreatic cancers and supporting the development of anti-stromal therapies.
  26. Nat Commun. 2020 10 13. 11(1): 5145
    Chrysafi P, Perakakis N, Farr OM, Stefanakis K, Peradze N, Sala-Vila A, Mantzoros CS.
      Based on studies in mice, leptin was expected to decrease body weight in obese individuals. However, the majority of the obese are hyperleptinemic and do not respond to leptin treatment, suggesting the presence of leptin tolerance and questioning the role of leptin as regulator of energy balance in humans. We thus performed detailed novel measurements and analyses of samples and data from our clinical trials biobank to investigate leptin effects on mechanisms of weight regulation in lean normo- and mildly hypo-leptinemic individuals without genetic disorders. We demonstrate that short-term leptin administration alters food intake during refeeding after fasting, whereas long-term leptin treatment reduces fat mass and body weight, and transiently alters circulating free fatty acids in lean mildly hypoleptinemic individuals. Leptin levels before treatment initiation and leptin dose do not predict the observed weight loss in lean individuals suggesting a saturable effect of leptin. In contrast to data from animal studies, leptin treatment does not affect energy expenditure, lipid utilization, SNS activity, heart rate, blood pressure or lean body mass.
  27. Science. 2020 Oct 16. pii: eaba2644. [Epub ahead of print]370(6514):
    Venturini V, Pezzano F, Català Castro F, Häkkinen HM, Jiménez-Delgado S, Colomer-Rosell M, Marro M, Tolosa-Ramon Q, Paz-López S, Valverde MA, Weghuber J, Loza-Alvarez P, Krieg M, Wieser S, Ruprecht V.
      The physical microenvironment regulates cell behavior during tissue development and homeostasis. How single cells decode information about their geometrical shape under mechanical stress and physical space constraints within tissues remains largely unknown. Here, using a zebrafish model, we show that the nucleus, the biggest cellular organelle, functions as an elastic deformation gauge that enables cells to measure cell shape deformations. Inner nuclear membrane unfolding upon nucleus stretching provides physical information on cellular shape changes and adaptively activates a calcium-dependent mechanotransduction pathway, controlling actomyosin contractility and migration plasticity. Our data support that the nucleus establishes a functional module for cellular proprioception that enables cells to sense shape variations for adapting cellular behavior to their microenvironment.
  28. Cancer Discov. 2020 Oct 15. pii: CD-20-1202. [Epub ahead of print]
    Espinet E, Gu Z, Imbusch CD, Giese NA, Buscher M, Safavi M, Weisenburger S, Klein C, Vogel V, Falcone M, Insua-Rodriguez J, Reitberger M, Thiel V, Kossi SO, Muckenhuber A, Sarai K, Lee AY, Backx E, Zarei S, Gaida MM, Rodriguez-Paredes M, Donato E, Yen HY, Eils R, Schlesner M, Pfarr N, Hackert T, Plass C, Brors B, Steiger K, Weichenhan D, Arda HE, Rooman I, Kopp JL, Strobel O, Weichert W, Sprick MR, Trumpp A.
      Pancreatic ductal adenocarcinoma (PDAC) is characterized by extensive desmoplasia, which challenges the molecular analyses of bulk tumor samples. Here we FACS-purified epithelial cells from human PDAC and normal pancreas and derived their genome-wide transcriptome and DNA methylome landscapes. Clustering based on DNA methylation revealed two distinct PDAC groups displaying different methylation patterns at regions encoding repeat elements. Methylationlow tumors are characterized by higher expression of endogenous retroviral (ERV) transcripts and dsRNA sensors which leads to a cell intrinsic activation of an interferon signature (IFNsign). This results in a pro-tumorigenic microenvironment and poor patient outcome. Methylationlow/IFNsignhigh and Methylationhigh/IFNsignlow PDAC cells preserve lineage traits, respective of normal ductal or acinar pancreatic cells. Moreover, ductal-derived KrasG12D/Trp53-/- mouse PDACs show higher expression of IFNsign compared to acinar-derived counterparts. Collectively, our data point to two different origins and etiologies of human PDACs, with the aggressive Methylationlow/IFNsignhigh subtype potentially targetable by agents blocking intrinsic IFN-signaling.
  29. FASEB J. 2020 Oct 13.
    Carneros D, Medina-Gómez G, Giralt M, León-Camacho M, Campbell M, Moreno-Aliaga MJ, Villarroya F, Bustos M.
      It is becoming clear that several human pathologies are caused by altered metabolic adaptations. During liver development, there are physiological changes, from the predominant utilization of glucose (fetal life) to the use of lipids (postnatal life). Fasting is another physiological stress that elicits well-known metabolic adjustments. We have reported the metabolic properties of cardiotrophin-1 (CT-1), a member of the interleukin-6 family of cytokines. Here, we aimed at analyzing the role of CT-1 in response to these metabolic changes. We used different in vivo models. Furthermore, a differential study was carried out with wild-type and CT-1 null mice in fed (ad libitum) and food-restricted conditions. We demonstrated that Ct-1 is a metabolic gene induced in the liver via PPARα in response to lipids in mice (neonates- and food-restricted adults). We found that Ct-1 mRNA expression in white adipose tissue directly involved PPARα and PPARγ. Finally, the physiological role of CT-1 in fasting is confirmed by the impaired food restriction-induced adipose tissue lipid mobilization in CT-1 null mice. Our findings support a previously unrecognized physiological role of CT-1 in metabolic adaptations, through the regulation of lipid metabolism and contributes to fasting-induced free fatty acid mobilization.
    Keywords:  adipose tissue; fatty acid mobilization; food restriction; lipids; peroxisome proliferator-activated receptors
  30. Nature. 2020 Oct 14.
    Bick AG, Weinstock JS, Nandakumar SK, Fulco CP, Bao EL, Zekavat SM, Szeto MD, Liao X, Leventhal MJ, Nasser J, Chang K, Laurie C, Burugula BB, Gibson CJ, Lin AE, Taub MA, Aguet F, Ardlie K, Mitchell BD, Barnes KC, Moscati A, Fornage M, Redline S, Psaty BM, Silverman EK, Weiss ST, Palmer ND, Vasan RS, Burchard EG, Kardia SLR, He J, Kaplan RC, Smith NL, Arnett DK, Schwartz DA, Correa A, de Andrade M, Guo X, Konkle BA, Custer B, Peralta JM, Gui H, Meyers DA, McGarvey ST, Chen IY, Shoemaker MB, Peyser PA, Broome JG, Gogarten SM, Wang FF, Wong Q, Montasser ME, Daya M, Kenny EE, North KE, Launer LJ, Cade BE, Bis JC, Cho MH, Lasky-Su J, Bowden DW, Cupples LA, Mak ACY, Becker LC, Smith JA, Kelly TN, Aslibekyan S, Heckbert SR, Tiwari HK, Yang IV, Heit JA, Lubitz SA, Johnsen JM, Curran JE, Wenzel SE, Weeks DE, Rao DC, Darbar D, Moon JY, Tracy RP, Buth EJ, Rafaels N, Loos RJF, Durda P, Liu Y, Hou L, Lee J, Kachroo P, Freedman BI, Levy D, Bielak LF, Hixson JE, Floyd JS, Whitsel EA, Ellinor PT, Irvin MR, Fingerlin TE, Raffield LM, Armasu SM, Wheeler MM, Sabino EC, Blangero J, Williams LK, Levy BD, Sheu WH, Roden DM, Boerwinkle E, Manson JE, Mathias RA, Desai P, Taylor KD, Johnson AD, , Auer PL, Kooperberg C, Laurie CC, Blackwell TW, Smith AV, Zhao H, Lange E, Lange L, Rich SS, Rotter JI, Wilson JG, Scheet P, Kitzman JO, Lander ES, Engreitz JM, Ebert BL, Reiner AP, Jaiswal S, Abecasis G, Sankaran VG, Kathiresan S, Natarajan P.
      Age is the dominant risk factor for most chronic human diseases, but the mechanisms through which ageing confers this risk are largely unknown1. The age-related acquisition of somatic mutations that lead to clonal expansion in regenerating haematopoietic stem cell populations has recently been associated with both haematological cancer2-4 and coronary heart disease5-this phenomenon is termed clonal haematopoiesis of indeterminate potential (CHIP)6. Simultaneous analyses of germline and somatic whole-genome sequences provide the opportunity to identify root causes of CHIP. Here we analyse high-coverage whole-genome sequences from 97,691 participants of diverse ancestries in the National Heart, Lung, and Blood Institute Trans-omics for Precision Medicine (TOPMed) programme, and identify 4,229 individuals with CHIP. We identify associations with blood cell, lipid and inflammatory traits that are specific to different CHIP driver genes. Association of a genome-wide set of germline genetic variants enabled the identification of three genetic loci associated with CHIP status, including one locus at TET2 that was specific to individuals of African ancestry. In silico-informed in vitro evaluation of the TET2 germline locus enabled the identification of a causal variant that disrupts a TET2 distal enhancer, resulting in increased self-renewal of haematopoietic stem cells. Overall, we observe that germline genetic variation shapes haematopoietic stem cell function, leading to CHIP through mechanisms that are specific to clonal haematopoiesis as well as shared mechanisms that lead to somatic mutations across tissues.
  31. FEBS J. 2020 Oct 17.
    Rudnik S, Damme M.
      Lysosomes are degradative organelles in eukaryotic cells mediating the hydrolytic catabolism of various macromolecules to small basic building blocks. These low molecular weight metabolites are transported across the lysosomal membrane and re-used in the cytoplasm and other organelles for biosynthetic pathways. Even though in the past 20 years our understanding of the lysosomal membrane regarding various transporters, other integral- and peripheral-membrane proteins, the lipid composition but also its turnover has greatly improved, there are still many unresolved questions concerning key aspects of the function of the lysosomal membrane. These include a possible function of lysosomes as a cellular storage compartment, yet unidentified transporters mediating the export e.g. of various amino acids, mechanisms mediating the transport of lysosomal membrane proteins from the Golgi apparatus to lysosomes, and the turnover of lysosomal membrane proteins. We here review the current knowledge about the lysosomal membrane and identify some of the open questions that need to be solved in the future for a comprehensive and complete understanding of how lysosomes communicate with other organelles, cellular processes, and pathways.
    Keywords:  Accessory subunits; Lysosomal Membrane; Lysosomal Storage Diseases; Transporter
  32. Adv Ther. 2020 Oct 16.
    Shibata M, Fukahori M, Kasamatsu E, Machii K, Hamauchi S.
      INTRODUCTION: This retrospective study focused on cancer cachexia in clinical practice. We evaluated the incidence of cancer cachexia and the relationship between cancer cachexia and overall survival (OS) or toxicities in patients with advanced colorectal cancer after undergoing first-line systemic chemotherapy.METHODS: We examined 150 patients with colorectal cancer who underwent first-line systemic chemotherapy between February 1, 2010 and August 31, 2016 at Shizuoka Cancer Center Hospital and Kurume University Hospital. Cancer cachexia was defined as > 5% weight loss or > 2% weight loss with a body mass index of < 20 kg/m2 within the past 6 months according to the European Palliative Care Research Collaborative criteria.
    RESULTS: One hundred patients from Shizuoka Cancer Center and 50 from Kurume University Hospital were registered. Median age and body mass index were 65 years (range 29-85) and 21.7 kg/m2 (14.8-32.5), respectively. Cumulative incidence of cancer cachexia was 50.7% at 24 weeks, and reached 91.3% over the whole study period. OS was significantly different between patients with and without cancer cachexia within 24 weeks after starting first-line treatment, although the onset of cancer cachexia within 24 weeks could not be considered as an independent prognostic factor for OS. Severe appetite loss and fatigue tended to occur more frequently in patients with cancer cachexia within 24 weeks.
    CONCLUSION: Cancer cachexia appears to have an onset in approximately half of patients with advanced colorectal cancer within 24 weeks after starting first-line treatment. Although causal relationships were controversial, the onset of cancer cachexia within 24 weeks tends to be related to worse outcomes. Thus, it would be better to monitor weight loss leading to cachexia in patients with advanced colorectal cancer, especially within 24 weeks after starting first-line chemotherapy.
    TRIAL REGISTRATION: University Hospital Medical Information Network Clinical Trials Registry (UMIN000035002).
    Keywords:  Adverse events; Cancer cachexia; Colorectal cancer; Incidence; Survival
  33. Pancreatology. 2020 Oct 10. pii: S1424-3903(20)30783-3. [Epub ahead of print]
    Fahr L, Sunami Y, Maeritz N, Steiger K, Grünewald TGP, Gericke M, Kong B, Raulefs S, Mayerle J, Michalski CW, Regel I, Kleeff J.
      BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) harbors mutant KRAS as the most common driver mutation. Studies on mouse models have uncovered the tumorigenic characteristics of the Kras oncogene driving pancreatic carcinogenesis. Similarly, Ewing sarcoma predominantly depends on the occurrence of the EWSR1-FLI1 fusion oncogene. The expression of EWSR1-FLI1 affects pro-tumorigenic pathways and induces cell transformation. In this study, we investigated whether mutant Kras could be exchanged by another potent oncogene, such as EWSR1-FLI1, to initiate pancreatic cancer development.METHODS: We generated two conditional mouse models expressing mutant KrasG12D (KC) or the EWSR1-FLI1 oncogene (E/F) in pancreas cells. Pancreatic tissue was collected from the mice at 4-6 weeks and 11-13 weeks of age as well as from survival cohorts to determine the development of spontaneous acinar-to-ductal metaplasia (ADM) and neoplastic lesions. Immunohistochemistry and immunofluorescence staining were performed to characterize and quantify changes in tissue morphology.
    RESULTS: The expression of the EWSR1-FLI1 fusion protein in pancreas cells was confirmed by positive FLI1 immunohistochemistry staining. Notably, the EWSR1-FLI1 expression in pancreas cells resulted in a strong depletion of the acinar cell mass and an extensive lipomatosis. Although the E/F mice exhibited spontaneous ADM formation and a shorter overall survival rate compared to KC mice, no development of neoplastic lesion was observed in aging E/F mice.
    CONCLUSIONS: The expression of the EWSR1-FLI1 oncogene leads to a strong pancreatic atrophy and lipomatosis. ADM formation indicates that pancreatic acinar cells are susceptible for EWSR1-FLI1-mediated oncogenic transformation to a limited extent. However, the EWSR1-FLI1 oncogene is insufficient to induce pancreatic cancer development.
    Keywords:  Adipocytes; Cellular transformation; EWSR1-FLI1; Perilipin
  34. Aging Cell. 2020 Oct 13. e13260
    Gauthier BR, Sola-García A, Cáliz-Molina MÁ, Lorenzo PI, Cobo-Vuilleumier N, Capilla-González V, Martin-Montalvo A.
      Thyroid function is central in the control of physiological and pathophysiological processes. Studies in animal models and human research have determined that thyroid hormones modulate cellular processes relevant for aging and for the majority of age-related diseases. While several studies have associated mild reductions on thyroid hormone function with exceptional longevity in animals and humans, alterations in thyroid hormones are serious medical conditions associated with unhealthy aging and premature death. Moreover, both hyperthyroidism and hypothyroidism have been associated with the development of certain types of diabetes and cancers, indicating a great complexity of the molecular mechanisms controlled by thyroid hormones. In this review, we describe the latest findings in thyroid hormone research in the field of aging, diabetes, and cancer, with a special focus on hepatocellular carcinomas. While aging studies indicate that the direct modulation of thyroid hormones is not a viable strategy to promote healthy aging or longevity and the development of thyromimetics is challenging due to inefficacy and potential toxicity, we argue that interventions based on the use of modulators of thyroid hormone function might provide therapeutic benefit in certain types of diabetes and cancers.
  35. Cells. 2020 Oct 11. pii: E2272. [Epub ahead of print]9(10):
    Adams V, Gußen V, Zozulya S, Cruz A, Moriscot A, Linke A, Labeit S.
      : Patients with malignant tumors frequently suffer during disease progression from a syndrome referred to as cancer cachexia (CaCax): CaCax includes skeletal muscle atrophy and weakness, loss of bodyweight, and fat tissues. Currently, there are no FDA (Food and Drug Administration) approved treatments available for CaCax. Here, we studied skeletal muscle atrophy and dysfunction in a murine CaCax model by injecting B16F10 melanoma cells into mouse thighs and followed mice during melanoma outgrowth. Skeletal muscles developed progressive weakness as detected by wire hang tests (WHTs) during days 13-23. Individual muscles analyzed at day 24 had atrophy, mitochondrial dysfunction, augmented metabolic reactive oxygen species (ROS) stress, and a catabolically activated ubiquitin proteasome system (UPS), including upregulated MuRF1. Accordingly, we tested as an experimental intervention of recently identified small molecules, Myomed-205 and -946, that inhibit MuRF1 activity and MuRF1/MuRF2 expression. Results indicate that MuRF1 inhibitor fed attenuated induction of MuRF1 in tumor stressed muscles. In addition, the compounds augmented muscle performance in WHTs and attenuated muscle weight loss. Myomed-205 and -946 also rescued citrate synthase and complex-1 activities in tumor-stressed muscles, possibly suggesting that mitochondrial-metabolic and muscle wasting effects in this CaCax model are mechanistically connected. Inhibition of MuRF1 during tumor cachexia may represent a suitable strategy to attenuate skeletal muscle atrophy and dysfunction.
    Keywords:  MuRF1; cancer cachexia; chemical biology; melanoma tumors; mitochondrial metabolism; muscle wasting
  36. J Cell Biol. 2020 Nov 02. pii: e202003024. [Epub ahead of print]219(11):
    Tirrell PS, Nguyen KN, Luby-Phelps K, Friedman JR.
      MICOS is a conserved multisubunit complex that localizes to mitochondrial cristae junctions and organizes cristae positioning within the organelle. MICOS is organized into two independent subcomplexes; however, the mechanisms that dictate the assembly and spatial positioning of each MICOS subcomplex are poorly understood. Here, we determine that MICOS subcomplexes target independently of one another to sites on the inner mitochondrial membrane that are in proximity to contact sites between mitochondria and the ER. One subcomplex, composed of Mic27/Mic26/Mic10/Mic12, requires ERMES complex function for its assembly. In contrast, the principal MICOS component, Mic60, self-assembles and localizes in close proximity to the ER through an independent mechanism. We also find that Mic60 can uniquely redistribute adjacent to forced mitochondria-vacuole contact sites. Our data suggest that nonoverlapping properties of interorganelle contact sites provide spatial cues that enable MICOS assembly and ultimately lead to proper physical and functional organization of mitochondria.
  37. Gastroenterology. 2020 Oct 12. pii: S0016-5085(20)35244-6. [Epub ahead of print]
    Huang J, Lok V, Ngai CH, Zhang L, Yuan J, Lao XQ, Ng K, Chong C, Zheng ZJ, Wong MC.
      BACKGROUND & AIMS: We evaluated global and regional burdens of, risk factors for, and epidemiologic trends in pancreatic cancer among groups of different sexes and ages.METHODS: We used data from the GLOBOCAN database to estimate pancreatic cancer incidence and mortality in 184 countries. We examined the association between lifestyle and metabolic risk factors, extracted from the World Health Organization Global Health Observatory database, and pancreatic cancer incidence and mortality by univariable and multivariable linear regression. We retrieved country-specific on age-standardized rates (ASRs) of incidence and mortalities from cancer registries from 48 countries through 2017 for trend analysis by joinpoint regression analysis.
    RESULTS: The highest incidence and mortality of pancreatic cancer were in regions with very high (ASRs, 7.7 and 4.9) and high HDIs (ASRs, 6.9 and 4.6) in 2018. Countries with higher incidence and mortality were more likely to have higher prevalence of smoking, alcohol drinking, physical inactivity, obesity, hypertension, and high cholesterol. From 2008 to 2017, 2007 to 2016, or 2003 to 2012, depending on the availability of the data, there were increases in incidence among men and women in 14 (average annual percent changes [AAPCs], 8.85 to 0.41) and 17 (AAPCs, 6.04 to 0.87) countries, respectively. For mortality, the increase was observed in eight (AAPCs, 4.20 to 0.55) countries among men and 14 (AAPCs, 5.83 to 0.78) countries among women. While the incidence increased in 18 countries (AAPCs, 7.83 to 0.91) among individuals 50 years or older, an increasing trend in pancreatic cancer was also identified among individuals younger than 50 years and 40 years in eight (AAPCs, 8.75 to 2.82) and four (AAPCs, 11.07 to 8.31) countries, respectively.
    CONCLUSIONS: In an analysis of data from 48 countries, we found increasing incidence and mortality trends in pancreatic cancer, especially among women and populations 50 years or older, but also among younger individuals. More preventive efforts are recommended for these populations.
    Keywords:  ASR; epidemiology; pancreas; trend analysis
  38. Cell Rep. 2020 Oct 13. pii: S2211-1247(20)31237-7. [Epub ahead of print]33(2): 108248
    Kent S, Brown K, Yang CH, Alsaihati N, Tian C, Wang H, Ren X.
      Compartmentalization by liquid-liquid phase separation is implicated in transcription. It remains unclear whether and how transcriptional condensates accelerate the search of transcriptional regulatory factors for their target sites. Furthermore, the molecular mechanisms by which regulatory factors nucleate on chromatin to assemble transcriptional condensates remain incompletely understood. The CBX-PRC1 complexes compartmentalize key developmental regulators for repression through phase-separated condensates driven by the chromobox 2 (CBX2) protein. Here, by using live-cell single-molecule imaging, we show that CBX2 nucleates on chromatin independently of H3K27me3 and CBX-PRC1. The interactions between CBX2 and DNA are essential for nucleating CBX-PRC1 on chromatin to assemble condensates. The assembled condensates shorten 3D diffusion time and reduce trials for finding specific sites through revisiting the same or adjacent sites repetitively, thereby accelerating CBX2 in searching for target sites. Overall, our data suggest a generic mechanism by which transcriptional regulatory factors nucleate to assemble condensates that accelerate their target-search process.
    Keywords:  CBX2; PRC1; PcG; chromatin; compartmentalization; epigenetics; liquid-liquid phase separation; nucleation; single-molecule imaging; target-search kinetics
  39. Science. 2020 Oct 16. pii: eaba2894. [Epub ahead of print]370(6514):
    Lomakin AJ, Cattin CJ, Cuvelier D, Alraies Z, Molina M, Nader GPF, Srivastava N, Saez PJ, Garcia-Arcos JM, Zhitnyak IY, Bhargava A, Driscoll MK, Welf ES, Fiolka R, Petrie RJ, De Silva NS, González-Granado JM, Manel N, Lennon-Duménil AM, Müller DJ, Piel M.
      The microscopic environment inside a metazoan organism is highly crowded. Whether individual cells can tailor their behavior to the limited space remains unclear. In this study, we found that cells measure the degree of spatial confinement by using their largest and stiffest organelle, the nucleus. Cell confinement below a resting nucleus size deforms the nucleus, which expands and stretches its envelope. This activates signaling to the actomyosin cortex via nuclear envelope stretch-sensitive proteins, up-regulating cell contractility. We established that the tailored contractile response constitutes a nuclear ruler-based signaling pathway involved in migratory cell behaviors. Cells rely on the nuclear ruler to modulate the motive force that enables their passage through restrictive pores in complex three-dimensional environments, a process relevant to cancer cell invasion, immune responses, and embryonic development.
  40. Cancer Prev Res (Phila). 2020 Oct 16. pii: canprevres.0403.2020. [Epub ahead of print]
    Udgata S, Takenaka N, Bamlet WR, Oberg AL, Yee SS, Carpenter EL, Herman D, Kim J, Petersen GM, Zaret KS.
      Pancreatic ductal adenocarcinoma (PDAC) is often diagnosed too late for effective therapy. The classic strategy for early detection biomarker advancement consists of initial retrospective phases of discovery and validation with tissue samples taken from individuals diagnosed with disease, compared to controls. Using this approach, we previously reported the discovery of a blood biomarker panel consisting of thrombospondin-2 (THBS2) and CA19-9 that together could discriminate resectable stage I and IIa PDAC as well as stages III and IV PDAC, with c-statistic values in the range of 0.96-0.97 in two Phase 2 studies. We now report that in two studies of blood samples prospectively collected from one to fifteen years prior to a PDAC diagnosis (Mayo Clinic and PLCO cohorts), THBS2 and/or CA19-9 failed to discriminate cases from healthy controls at the AUC=0.8 needed. We conclude that PDAC progression may be heterogeneous and for some individuals can be more rapid than generally appreciated. It is important that PDAC early detection studies incorporate high-risk, prospective pre-diagnostic cohorts into discovery and validation studies.
  41. J Exp Med. 2021 Jan 04. pii: e20201414. [Epub ahead of print]218(1):
    Fedele C, Li S, Teng KW, Foster CJR, Peng D, Ran H, Mita P, Geer MJ, Hattori T, Koide A, Wang Y, Tang KH, Leinwand J, Wang W, Diskin B, Deng J, Chen T, Dolgalev I, Ozerdem U, Miller G, Koide S, Wong KK, Neel BG.
      KRAS is the most frequently mutated human oncogene, and KRAS inhibition has been a longtime goal. Recently, inhibitors were developed that bind KRASG12C-GDP and react with Cys-12 (G12C-Is). Using new affinity reagents to monitor KRASG12C activation and inhibitor engagement, we found that an SHP2 inhibitor (SHP2-I) increases KRAS-GDP occupancy, enhancing G12C-I efficacy. The SHP2-I abrogated RTK feedback signaling and adaptive resistance to G12C-Is in vitro, in xenografts, and in syngeneic KRASG12C-mutant pancreatic ductal adenocarcinoma (PDAC) and non-small cell lung cancer (NSCLC). SHP2-I/G12C-I combination evoked favorable but tumor site-specific changes in the immune microenvironment, decreasing myeloid suppressor cells, increasing CD8+ T cells, and sensitizing tumors to PD-1 blockade. Experiments using cells expressing inhibitor-resistant SHP2 showed that SHP2 inhibition in PDAC cells is required for PDAC regression and remodeling of the immune microenvironment but revealed direct inhibitory effects on tumor angiogenesis and vascularity. Our results demonstrate that SHP2-I/G12C-I combinations confer a substantial survival benefit in PDAC and NSCLC and identify additional potential combination strategies.
  42. Aging (Albany NY). 2020 Oct 13. 12
    Feng L, Wang K, Tang P, Chen S, Liu T, Lei J, Yuan R, Hu Z, Li W, Yu X.
      The dysregulation of deubiquitinating enzymes (DUBs), which regulate the stability of most cellular proteins, has been implicated in many human diseases, including cancers. Thus, DUBs can be considered potential therapeutic targets for many cancers. However, the role of deubiquitinase ubiquitin-specific protease 18 (USP18) in pancreatic cancer remains unknown. Here, we found that the deubiquitinase ubiquitin-specific protease 18 (USP18) is significantly upregulated in pancreatic cancer and is correlated with a shorter median overall and relapse-free survival. A functional assay demonstrated that overexpression of USP18 resulted in increased proliferation of pancreatic cancer cells. Conversely, these phenomena were reversed after USP18 was silenced in pancreatic cancer cells. Further investigation revealed that USP18 promoted cell progression by increasing c-Myc expression, which has been reported to control pancreatic cancer progression, and our data demonstrated that c-Myc is key for USP18-mediated pancreatic cancer cell progression in vitro and in vivo. Moreover, we found that USP18 promoted pancreatic cancer progression via upregulation of Notch-1-dependent c-Myc. Mechanistically, USP18 interacts with and removes K48-linked ubiquitin chains from Notch1, thereby stabilizing Notch1 and promoting the Notch1-c-Myc pathway. Our work identifies and validates USP18 as a pancreatic cancer oncogene and provides a potential druggable target for this intractable disease.
    Keywords:  Notch1; USP18; c-Myc; pancreatic cancer; ubiquitination
  43. Clin Cancer Res. 2020 Oct 13. pii: clincanres.2831.2020. [Epub ahead of print]
    Topham JT, Karasinska JM, Lee MK, Csizmok V, Williamson LM, Jang GH, Denroche RE, Tsang ES, Kalloger SE, Wong HL, O'Kane GM, Moore RA, Mungall AJ, Notta F, Loree JM, Wilson JM, Bathe OF, Tang PA, Goodwin RA, Knox JJ, Gallinger S, Laskin J, Marra MA, Jones SJ, Renouf DJ, Schaeffer DF.
      Background RNA-sequencing-based subtyping of pancreatic ductal adenocarcinoma (PDAC) has been reported by multiple research groups, each using different methodologies and patient cohorts. 'Classical' and 'basal-like' PDAC subtypes are associated with survival differences, with basal-like tumors associated with worse prognosis. We amalgamated various PDAC subtyping tools to evaluate the potential of such tools to be reliable in clinical practice. Methods Sequencing data for 574 PDAC tumors was obtained from prospective trials and retrospective public databases. Six published PDAC subtyping strategies (Moffitt regression tools, clustering-based Moffitt, Collisson, Bailey, and Karasinska subtypes) were employed on each sample, and results were tested for subtype call consistency and association with survival. Results Basal-like and classical subtype calls were concordant in 88% of patient samples, and survival outcomes were significantly different (p<0.05) between prognostic subtypes. 12% of tumors had subtype-discordant calls across the different methods, showing intermediate survival in univariate and multivariate survival analyses. Transcriptional profiles compatible with that of a hybrid subtype signature were observed for subtype-discordant tumors, in which classical and basal-like genes were concomitantly expressed. Subtype-discordant tumors showed intermediate molecular characteristics, including subtyping gene expression (p<0.0001) and mutant KRAS allelic imbalance (p<0.001). Conclusions Nearly one in six patients with PDAC have tumors that fail to reliably fall into the classical or basal-like PDAC subtype categories, based on two regression tools aimed towards clinical practice. Rather, these patient tumors show intermediate prognostic and molecular traits. We propose close consideration of the non-binary nature of PDAC subtypes for future incorporation of subtyping into clinical practice.
  44. Proc Natl Acad Sci U S A. 2020 Oct 13. pii: 201922755. [Epub ahead of print]
    Gonzales AL, Klug NR, Moshkforoush A, Lee JC, Lee FK, Shui B, Tsoukias NM, Kotlikoff MI, Hill-Eubanks D, Nelson MT.
      The essential function of the circulatory system is to continuously and efficiently supply the O2 and nutrients necessary to meet the metabolic demands of every cell in the body, a function in which vast capillary networks play a key role. Capillary networks serve an additional important function in the central nervous system: acting as a sensory network, they detect neuronal activity in the form of elevated extracellular K+ and initiate a retrograde, propagating, hyperpolarizing signal that dilates upstream arterioles to rapidly increase local blood flow. Yet, little is known about how blood entering this network is distributed on a branch-to-branch basis to reach specific neurons in need. Here, we demonstrate that capillary-enwrapping projections of junctional, contractile pericytes within a postarteriole transitional region differentially constrict to structurally and dynamically determine the morphology of capillary junctions and thereby regulate branch-specific blood flow. We further found that these contractile pericytes are capable of receiving propagating K+-induced hyperpolarizing signals propagating through the capillary network and dynamically channeling red blood cells toward the initiating signal. By controlling blood flow at junctions, contractile pericytes within a functionally distinct postarteriole transitional region maintain the efficiency and effectiveness of the capillary network, enabling optimal perfusion of the brain.
    Keywords:  cerebral blood flow; functional hyperemia; pericytes
  45. Cells. 2020 Oct 08. pii: E2258. [Epub ahead of print]9(10):
    Diehl KL, Vorac J, Hofmann K, Meiser P, Unterweger I, Kuerschner L, Weighardt H, Förster I, Thiele C.
      A high fat Western-style diet leads to hepatic steatosis that can progress to steatohepatitis and ultimately cirrhosis or liver cancer. The mechanism that leads to the development of steatosis upon nutritional overload is complex and only partially understood. Using click chemistry-based metabolic tracing and microscopy, we study the interaction between Kupffer cells and hepatocytes ex vivo. In the early phase of steatosis, hepatocytes alone do not display significant deviations in fatty acid metabolism. However, in co-cultures or supernatant transfer experiments, we show that tumor necrosis factor (TNF) secretion by Kupffer cells is necessary and sufficient to induce steatosis in hepatocytes, independent of the challenge of hepatocytes with elevated fatty acid levels. We further show that free fatty acid (FFA) or lipopolysaccharide are both able to trigger release of TNF from Kupffer cells. We conclude that Kupffer cells act as the primary sensor for both FFA overload and bacterial lipopolysaccharide, integrate these signals and transmit the information to the hepatocyte via TNF secretion. Hepatocytes react by alteration in lipid metabolism prominently leading to the accumulation of triacylglycerols (TAGs) in lipid droplets, a hallmark of steatosis.
    Keywords:  lipids/chemistry; metabolic disease; non-alcoholic fatty liver disease; nutrition/lipids
  46. Sci Adv. 2020 Aug;pii: eabb2878. [Epub ahead of print]6(35):
    Christoffersson G, Ratliff SS, von Herrath MG.
      The notably lobular distribution of immune lesions in type 1 diabetes (T1D) has been hypothesized to be the result of innervation within the pancreas. To investigate whether neuroimmune interactions could explain this phenomenon, we explored the impact of sympathetic signaling in the RIP-LCMV-GP mouse model of autoimmune diabetes. In this model, the CD8+ T cell attack on β cells replicates a key pathogenic feature of human T1D. We found that inhibition of α1 adrenoceptors, ablation of sympathetic nerves, and surgical denervation all had a protective effect in this model, without affecting the systemic presence of β cell-reactive CD8+ T cells. In vivo multiphoton imaging revealed a local effect within pancreatic islets including limited infiltration of both macrophages and β cell-specific CD8+ T cells. Islet-resident macrophages expressed adrenoceptors and were responsive to catecholamines. Islet macrophages may therefore constitute a pivotal neuroimmune signaling relay and could be a target for future interventions in T1D.
  47. Clin Cancer Res. 2020 Oct 12. pii: clincanres.2718.2020. [Epub ahead of print]
    Hao HX, Liu C, Lu H, Wang H, Loo A, Zhang X, Yang G, Kowal C, Delach S, Wang Y, Goldoni S, Hastings WD, Wong K, Gao H, Meyer MJ, Moody S, LaMarche MJ, Engelman JA, Williams JA, Hammerman PS, Abrams TJ, Mohseni M, Caponigro G.
      PURPOSE: SHP2 inhibitors offer an appealing and novel approach to inhibit RTK signaling, which is the oncogenic driver in many tumors or is frequently feedback activated in response to targeted therapies including RTKi and MAPKi. We seek to evaluate the efficacy and synergistic mechanisms of combinations with a novel SHP2 inhibitor TNO155 to inform their clinical development.EXPERIMENTAL DESIGN: The combinations of TNO155 with EGFRi, BRAFi, KRASG12Ci, CDK4/6i and anti-PD-1 antibody were tested in appropriate cancer models in vitro and in vivo, and their effects on downstream signaling were examined.
    RESULTS: In EGFR mutant lung cancer models, combination benefit of TNO155 and the EGFRi nazartinib was observed, coincident with sustained ERK inhibition. In BRAFV600E colorectal cancer models, TNO155 synergized with BRAF plus MEK inhibitors by blocking ERK feedback activation by different RTKs. In KRASG12C cancer cells, TNO155 effectively blocked the feedback activation of wild-type KRAS or other RAS isoforms induced by KRASG12Ci and greatly enhanced efficacy. In addition, TNO155 and the CDK4/6 inhibitor ribociclib showed combination benefit in a large panel of lung and colorectal cancer patient-derived xenografts, including those with KRAS mutations. Lastly, TNO155 effectively inhibited RAS activation by CSF1R, which is critical for the maturation of immunosuppressive tumor associated macrophages, and showed combination activity with anti-PD-1 antibody.
    CONCLUSIONS: Our findings suggest TNO155 is an effective agent for blocking both tumor-promoting and immune-suppressive RTK signaling in RTK- and MAPK-driven cancers and their tumor microenvironment. Our data provide the rationale for evaluating these combinations clinically.
  48. Proc Natl Acad Sci U S A. 2020 Oct 12. pii: 202007918. [Epub ahead of print]
    Rapuano KM, Laurent JS, Hagler DJ, Hatton SN, Thompson WK, Jernigan TL, Dale AM, Casey BJ, Watts R.
      The prevalence of obesity in children and adolescents worldwide has quadrupled since 1975 and is a key predictor of obesity later in life. Previous work has consistently observed relationships between macroscale measures of reward-related brain regions (e.g., the nucleus accumbens [NAcc]) and unhealthy eating behaviors and outcomes; however, the mechanisms underlying these associations remain unclear. Recent work has highlighted a potential role of neuroinflammation in the NAcc in animal models of diet-induced obesity. Here, we leverage a diffusion MRI technique, restriction spectrum imaging, to probe the microstructure (cellular density) of subcortical brain regions. More specifically, we test the hypothesis that the cell density of reward-related regions is associated with obesity-related metrics and early weight gain. In a large cohort of nine- and ten-year-olds enrolled in the Adolescent Brain Cognitive Development (ABCD) study, we demonstrate that cellular density in the NAcc is related to individual differences in waist circumference at baseline and is predictive of increases in waist circumference after 1 y. These findings suggest a neurobiological mechanism for pediatric obesity consistent with rodent work showing that high saturated fat diets increase gliosis and neuroinflammation in reward-related brain regions, which in turn lead to further unhealthy eating and obesity.
    Keywords:  brain development; diffusion MRI; nucleus accumbens; pediatric obesity; restriction spectrum imaging
  49. Elife. 2020 Oct 14. pii: e58107. [Epub ahead of print]9
    Peterson NG, Stormo BM, Schoenfelder KP, King JS, Lee RR, Fox DT.
      Multiple nuclei sharing a common cytoplasm are found in diverse tissues, organisms, and diseases. Yet, multinucleation remains a poorly understood biological property. Cytoplasm sharing invariably involves plasma membrane breaches. In contrast, we discovered cytoplasm sharing without membrane breaching in highly resorptive Drosophila rectal papillae. During a six-hour developmental window, 100 individual papillar cells assemble a multinucleate cytoplasm, allowing passage of proteins of at least 62kDa throughout papillar tissue. Papillar cytoplasm sharing does not employ canonical mechanisms such as incomplete cytokinesis or muscle fusion pore regulators. Instead, sharing requires gap junction proteins (normally associated with transport of molecules <1kDa), which are positioned by membrane remodeling GTPases. Our work reveals a new role for apical membrane remodeling in converting a multicellular epithelium into a giant multinucleate cytoplasm.
    Keywords:  D. melanogaster; developmental biology
  50. Diabetes. 2020 Oct 12. pii: db191239. [Epub ahead of print]
    Jin Y, Ji Y, Song Y, Choe SS, Jeon YG, Na H, Nam TW, Kim HJ, Nahmgoong H, Kim SM, Kim JW, Nam KT, Seong JK, Hwang D, Park CB, Lee IH, Kim JB, Lee HW.
      Becn1/Beclin-1 is a core component of the class III phosphatidylinositol 3-kinase required for autophagosome formation and vesicular trafficking. Although Becn1 has been implicated in numerous diseases such as cancer, aging, and neurodegenerative disease, the role of Becn1 in white adipose tissue and related metabolic diseases remains elusive. Here we show that adipocyte-specific Becn1 knockout mice develop severe lipodystrophy, leading to adipose tissue inflammation, hepatic steatosis, insulin resistance. Ablation of Becn1 in adipocytes stimulates programmed cell death in a cell-autonomous manner, accompanied by elevated ER stress gene expression. Furthermore, we observed that Becn1 depletion sensitized mature adipocytes to ER stress, leading to accelerated cell death. Taken together, these data suggest that adipocyte Becn1 would serve as a crucial player for adipocyte survival and adipose tissue homeostasis.
  51. Autophagy. 2020 Oct 12. 1-16
    da Silva Rosa SC, Martens MD, Field JT, Nguyen L, Kereliuk SM, Hai Y, Chapman D, Diehl-Jones W, Aliani M, West AR, Thliveris J, Ghavami S, Rampitsch C, Dolinsky VW, Gordon JW.
      Lipotoxicity is a form of cellular stress caused by the accumulation of lipids resulting in mitochondrial dysfunction and insulin resistance in muscle. Previously, we demonstrated that the mitophagy receptor BNIP3L/Nix is responsive to lipotoxicity and accumulates in response to a high-fat (HF) feeding. To provide a better understanding of this observation, we undertook gene expression array and shot-gun metabolomics studies in soleus muscle from rodents on an HF diet. Interestingly, we observed a modest reduction in several autophagy-related genes. Moreover, we observed alterations in the fatty acyl composition of cardiolipins and phosphatidic acids. Given the reported roles of these phospholipids and BNIP3L in mitochondrial dynamics, we investigated aberrant mitochondrial turnover as a mechanism of impaired myocyte insulin signaling. In a series of gain-of-function and loss-of-function experiments in rodent and human myotubes, we demonstrate that BNIP3L accumulation triggers mitochondrial depolarization, calcium-dependent activation of DNM1L/DRP1, and mitophagy. In addition, BNIP3L can inhibit insulin signaling through activation of MTOR-RPS6KB/p70S6 kinase inhibition of IRS1, which is contingent on phosphatidic acids and RHEB. Finally, we demonstrate that BNIP3L-induced mitophagy and impaired glucose uptake can be reversed by direct phosphorylation of BNIP3L by PRKA/PKA, leading to the translocation of BNIP3L from the mitochondria and sarcoplasmic reticulum to the cytosol. These findings provide insight into the role of BNIP3L, mitochondrial turnover, and impaired myocyte insulin signaling during an overfed state when overall autophagy-related gene expression is reduced. Furthermore, our data suggest a mechanism by which exercise or pharmacological activation of PRKA may overcome myocyte insulin resistance. Abbreviations: BCL2: B cell leukemia/lymphoma 2; BNIP3L/Nix: BCL2/adenovirus E1B interacting protein 3-like; DNM1L/DRP1: dynamin 1-like; FUNDC1: FUN14 domain containing 1; IRS1: insulin receptor substrate 1; MAP1LC3A/LC3: microtubule-associated protein 1 light chain 3 alpha; MFN1: mitofusin 1; MFN2: mitofusin 2; MTOR: mechanistic target of rapamycin kinase; OPA1: OPA1 mitochondrial dynamin like GTPase; PDE4i: phosphodiesterase 4 inhibitor; PLD1: phospholipase D1; PLD6: phospholipase D family member 6; PRKA/PKA: protein kinase, AMP-activated; PRKCD/PKCδ: protein kinase C, delta; PRKCQ/PKCθ: protein kinase C, theta; RHEB: Ras homolog enriched in brain; RPS6KB/p70S6K: ribosomal protein S6 kinase; SQSTM1/p62: sequestosome 1; YWHAB/14-3-3β: tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein beta.
    Keywords:  Insulin signaling; MTOR; Nix; PKA; mitochondria; mitophagy; muscle
  52. Cell Death Dis. 2020 Oct 16. 11(10): 872
    Pedley R, King LE, Mallikarjun V, Wang P, Swift J, Brennan K, Gilmore AP.
      Apoptotic priming controls the commitment of cells to apoptosis by determining how close they lie to mitochondrial permeabilisation. Variations in priming are important for how both healthy and cancer cells respond to chemotherapeutic agents, but how it is dynamically coordinated by Bcl-2 proteins remains unclear. The Bcl-2 family protein Bid is phosphorylated when cells enter mitosis, increasing apoptotic priming and sensitivity to antimitotic drugs. Here, we report an unbiased proximity biotinylation (BioID) screen to identify regulators of apoptotic priming in mitosis, using Bid as bait. The screen primarily identified proteins outside of the canonical Bid interactome. Specifically, we found that voltage-dependent anion-selective channel protein 2 (VDAC2) was required for Bid phosphorylation-dependent changes in apoptotic priming during mitosis. These results highlight the importance of the wider Bcl-2 family interactome in regulating the temporal control of apoptotic priming.
  53. Front Endocrinol (Lausanne). 2020 ;11 638
    García-Costela M, Escudero-Feliú J, Puentes-Pardo JD, San Juán SM, Morales-Santana S, Ríos-Arrabal S, Carazo Á, León J.
      Pancreatic cancer is one of the most lethal cancers worldwide due to its symptoms, early metastasis, and chemoresistance. Thus, the mechanisms contributing to pancreatic cancer progression require further exploration. Circadian rhythms are the daily oscillations of multiple biological processes regulated by an endogenous clock. Several evidences suggest that the circadian clock may play an important role in the cell cycle, cell proliferation and apoptosis. In addition, timing of chemotherapy or radiation treatment can influence the efficacy and toxicity treatment. Here, we revisit the studies on circadian clock as an emerging target for therapy in pancreatic cancer. We highlight those potential circadian genes regulators that are commonly affected in pancreatic cancer according to most recent reports.
    Keywords:  chemotherapy; circadian clock; metabolism; pancreatic cancer; precision medicine
  54. Hepatology. 2020 Oct 14.
    Ravichandra A, Filliol A, Schwabe RF.
      During chronic liver injury, hepatic stellate cells (HSC) differentiate from lipid-storing pericytes into extracellular matrix (ECM)-producing fibroblasts. While we tend to view these activated HSC as a homogenous fibrogenic cell population that accumulates in the fibrotic liver, this oversimplifies the dynamic nature of fibrogenesis, the different functional states of HSC and their ultimate fate. In parallel to their activation, HSC also undergo massive expansion under stimulation of cytokines such as platelet-derived growth factor beta, leading to their accumulation within fibrotic septa and ultimately HSC senescence. In a recent paper published in Nature, Amor et al. establish chimeric antigen receptor (CAR) T cells as new and powerful method for clearing senescent-cells and demonstrate that removal of senescent HSC ameliorates liver fibrosis (1).
  55. J Cell Biol. 2020 Dec 07. pii: e202001031. [Epub ahead of print]219(12):
    Endicott SJ, Ziemba ZJ, Beckmann LJ, Boynton DN, Miller RA.
      Chaperone-mediated autophagy (CMA) is the most selective form of lysosomal proteolysis, where individual peptides, recognized by a consensus motif, are translocated directly across the lysosomal membrane. CMA regulates the abundance of many disease-related proteins, with causative roles in neoplasia, neurodegeneration, hepatosteatosis, and other pathologies relevant to human health and aging. At the lysosomal membrane, CMA is inhibited by Akt-dependent phosphorylation of the CMA regulator GFAP. The INS-PI3K-PDPK1 pathway regulates Akt, but its role in CMA is unclear. Here, we report that inhibition of class I PI3K or PDPK1 activates CMA. In contrast, selective inhibition of class III PI3Ks does not activate CMA. Isolated liver lysosomes from mice treated with either of two orally bioavailable class I PI3K inhibitors, pictilisib or buparlisib, display elevated CMA activity, and decreased phosphorylation of lysosomal GFAP, with no change in macroautophagy. The findings of this study represent an important first step in repurposing class I PI3K inhibitors to modulate CMA in vivo.
  56. J Hepatobiliary Pancreat Sci. 2020 Oct 15.
    Inoue Y, Saiura A, Oba A, Ono Y, Mise Y, Ito H, Sasaki T, Ozaka M, Sasahira N, Takahashi Y.
      BACKGROUND/PURPOSE: We evaluated efficacy of neoadjuvant therapy with gemcitabine and nab-paclitaxel (GNP-NAT) in borderline resectable pancreatic cancer (BR-PC) patients comparing with conventional upfront surgery (UPS).METHODS: This single center retrospective study assessed 151 consecutive patients; 96 diagnosed in 2008-2014 underwent UPS (UPS group) and 55 diagnosed in 2015-2017 underwent GNP-NAT (GN group). Patient background, surgical, pathological, and survival outcomes were compared between groups.
    RESULTS: Age, sex, and pretreatment carbohydrate antigen 19-9 were similar between groups. After 4 courses of NAT-GNP, 46 GN patients (84%) underwent surgery while all UPS patients underwent surgery. Only 3 GN patients (5%) underwent nontherapeutic procedures, compared to 23 (24%) in the UPS group (P = 0.004). In the whole cohort, R0-resection was achieved in 40 GN patients (73%) vs. 45 UPS patients (47%; P = 0.004) and the 3-year overall survival was significantly higher in the GN group (median survival time, 31.9 vs. 18.1 months, P = 0.014). In the resection cohort, the R0-resection rate was 93% (GN) vs. 63% (UPS; P = 0.0007). There was no 90-day mortality in either group.
    CONCLUSIONS: Intention-to-treat-based analysis indicated considerable benefits of GNP-NAT in BR-PCs for long-term survival, contributing to improved tumor suppression and patient selection.
    Keywords:  borderline resectable; gemcitabine; nab-paclitaxel; neoadjuvant chemotherapy; pancreatic cancer
  57. Nucleic Acids Res. 2020 Oct 12. pii: gkaa858. [Epub ahead of print]
    Guan Y, Zhang C, Lyu G, Huang X, Zhang X, Zhuang T, Jia L, Zhang L, Zhang C, Li C, Tao W.
      The three-dimensional configuration of the chromatin architecture is known to be crucial for alterations in the transcriptional network; however, the underlying mechanisms of epigenetic control of senescence-related gene expression by modulating the chromatin architecture remain unknown. Here, we demonstrate frequent chromosomal compartment switching during mouse embryonic fibroblasts (MEFs) replicative senescence as characterized by senescence-inactivated (SIAEs) and -activated enhancers (SAEs) in topologically associated domains (TADs). Mechanistically, SAEs are closely correlated with senescence-associated secretory phenotype (SASP) genes, which are a key transcriptional feature of an aging microenvironment that contributes to tumor progression, aging acceleration, and immunoinflammatory responses. Moreover, SAEs can positively regulate robust changes in SASP expression. The transcription factor CCAAT/enhancer binding protein α (C/EBPα) is capable of enhancing SAE activity, which accelerates the emergence of SAEs flanking SASPs and the secretion of downstream factors, contributing to the progression of senescence. Our results provide novel insight into the TAD-related control of SASP gene expression by revealing hierarchical roles of the chromatin architecture, transcription factors, and enhancer activity in the regulation of cellular senescence.
  58. Dev Cell. 2020 Oct 12. pii: S1534-5807(20)30705-X. [Epub ahead of print]55(1): 97-107
    Goetz SK, Mahamid J.
      In the last decade, liquid-liquid phase separation has emerged as a fundamental principle in the organization of crowded cellular environments into functionally distinct membraneless compartments. It is now established that biomolecules can condense into various physical phases, traditionally defined for simple polymer systems, and more recently elucidated by techniques employed in life sciences. We review pioneering cryo-electron tomography studies that have begun to unravel a wide spectrum of molecular architectures, ranging from amorphous to crystalline assemblies, that underlie cellular condensates. These observations bring into question current interpretations of microscopic phase behavior. Furthermore, by examining emerging concepts of non-classical phase separation pathways in small-molecule crystallization, we draw parallels with biomolecular condensation that highlight aspects not yet fully explored. In particular, transient and metastable intermediates that might be challenging to capture experimentally inside cells could be probed through computational simulations and enable a multi-scale understanding of the subcellular organization governed by distinct phases.
  59. Elife. 2020 Oct 13. pii: e56554. [Epub ahead of print]9
    Galeano Niño JL, Pageon SV, Tay SS, Colakoglu F, Kempe D, Hywood J, Mazalo JK, Cremasco J, Govendir MA, Dagley LF, Hsu K, Rizzetto S, Zieba J, Rice G, Prior V, O'Neill GM, Williams RJ, Nisbet DR, Kramer B, Webb AI, Luciani F, Read MN, Biro M.
      Cytotoxic T lymphocytes (CTLs) are thought to arrive at target sites either via random search or following signals by other leukocytes. Here, we reveal independent emergent behaviour in CTL populations attacking tumour masses. Primary murine CTLs coordinate their migration in a process reminiscent of the swarming observed in neutrophils. CTLs engaging cognate targets accelerate the recruitment of distant T cells through long-range homotypic signalling, in part mediated via the diffusion of chemokines CCL3 and CCL4. Newly arriving CTLs augment the chemotactic signal, further accelerating mass recruitment in a positive feedback loop. Activated effector human T cells and chimeric antigen receptor (CAR) T cells similarly employ intra-population signalling to drive rapid convergence. Thus, CTLs recognising a cognate target can induce a localised mass response by amplifying the direct recruitment of additional T cells independently of other leukocytes.
    Keywords:  computational biology; human; immunology; inflammation; mouse; systems biology
  60. Sci Adv. 2020 Oct;pii: eabb8941. [Epub ahead of print]6(42):
    Chen H, Chen H, Zhang J, Wang Y, Simoneau A, Yang H, Levine AS, Zou L, Chen Z, Lan L.
      The cyclic GMP-AMP synthase (cGAS), a sensor of cytosolic DNA, is critical for the innate immune response. Here, we show that loss of cGAS in untransformed and cancer cells results in uncontrolled DNA replication, hyperproliferation, and genomic instability. While the majority of cGAS is cytoplasmic, a fraction of cGAS associates with chromatin. cGAS interacts with replication fork proteins in a DNA binding-dependent manner, suggesting that cGAS encounters replication forks in DNA. Independent of cGAMP and STING, cGAS slows replication forks by binding to DNA in the nucleus. In the absence of cGAS, replication forks are accelerated, but fork stability is compromised. Consequently, cGAS-deficient cells are exposed to replication stress and become increasingly sensitive to radiation and chemotherapy. Thus, by acting as a decelerator of DNA replication forks, cGAS controls replication dynamics and suppresses replication-associated DNA damage, suggesting that cGAS is an attractive target for exploiting the genomic instability of cancer cells.
  61. Nat Methods. 2020 Oct 12.
    Spark A, Kitching A, Esteban-Ferrer D, Handa A, Carr AR, Needham LM, Ponjavic A, Santos AM, McColl J, Leterrier C, Davis SJ, Henriques R, Lee SF.
      vLUME is a virtual reality software package designed to render large three-dimensional single-molecule localization microscopy datasets. vLUME features include visualization, segmentation, bespoke analysis of complex local geometries and exporting features. vLUME can perform complex analysis on real three-dimensional biological samples that would otherwise be impossible by using regular flat-screen visualization programs.
  62. Mech Ageing Dev. 2020 Oct 10. pii: S0047-6374(20)30178-0. [Epub ahead of print] 111382
    Omer A, Patel D, Moran JL, Lian XJ, Di Marco S, Gallouzi IE.
      Stress granules (SGs) are membraneless organelles formed in response to insult. These granules are related to pathological granules found in age-related neurogenerative diseases such as Parkinson's and Alzheimer's. Previously, we demonstrated that senescent cells, which accumulate with age, exposed to chronic oxidative stress, are unable to form SGs. Here, we show that the inability of senescent cells to form SGs correlates with an upregulation in both the heat-shock response and autophagy pathways, both of which are well-established promoters of SG disassembly. Our data also reveals that the knockdown of HSP70 and ATG5, important components of the heat-shock response and autophagy pathways, respectively, restores the number of SGs formed in senescent cells exposed to chronic oxidative stress. Surprisingly, under these conditions, the depletion of HSP70 or ATG5 did not affect the clearance of these SGs during their recovery from chronic stress. These data reveal that senescent cells possess a unique heat-shock and autophagy-dependent ability to impair the formation of SGs in response to chronic stress, thereby expanding the existing understanding of SG dynamics in senescent cells and their potential contribution to age-related neurodegenerative diseases.
    Keywords:  Ageing; Cellular Senescence; Molecular Biology; Oxidative Stress; Stress Granules
  63. J Cachexia Sarcopenia Muscle. 2020 Oct 14.
    Dolly A, Dumas JF, Servais S.
      Research investigators have shown a growing interest in investigating alterations underlying skeletal muscle wasting in patients with cancer. However, skeletal muscle dysfunctions associated with cancer cachexia have mainly been studied in preclinical models. In the present review, we summarize the results of clinical studies in which skeletal muscle biopsies were collected from cachectic vs. non-cachectic cancer patients. Most of these studies suggest the presence of significant physiological alterations in skeletal muscle from cachectic cancer patients. We suggest a hypothesis, which connects structural and metabolic parameters that may, at least in part, be responsible for the skeletal muscle atrophy characteristic of cancer cachexia. Finally, we discuss the importance of a better standardization of the diagnostic criteria for cancer cachexia, as well as the requirement for additional clinical studies to improve the robustness of these conclusions.
    Keywords:  Cancer cachexia; Clinical studies; Mitochondria; Myosteatosis; Skeletal muscle alterations
  64. Sci Signal. 2020 Oct 13. pii: eabb4778. [Epub ahead of print]13(653):
    Dhanaraman T, Singh S, Killoran RC, Singh A, Xu X, Shifman JM, Smith MJ.
      Small guanosine triphosphatases (GTPases) of the RAS superfamily signal by directly binding to multiple downstream effector proteins. Effectors are defined by a folded RAS-association (RA) domain that binds exclusively to GTP-loaded (activated) RAS, but the binding specificities of most RA domains toward more than 160 RAS superfamily GTPases have not been characterized. Ten RA domain family (RASSF) proteins comprise the largest group of related effectors and are proposed to couple RAS to the proapoptotic Hippo pathway. Here, we showed that RASSF1-6 formed complexes with the Hippo kinase ortholog MST1, whereas RASSF7-10 formed oligomers with the p53-regulating effectors ASPP1 and ASPP2. Moreover, only RASSF5 bound directly to activated HRAS and KRAS, and RASSFs did not augment apoptotic induction downstream of RAS oncoproteins. Structural modeling revealed that expansion of the RASSF effector family in vertebrates included amino acid substitutions to key residues that direct GTPase-binding specificity. We demonstrated that the tumor suppressor RASSF1A formed complexes with the RAS-related GTPases GEM, REM1, REM2, and the enigmatic RASL12. Furthermore, interactions between RASSFs and RAS GTPases blocked YAP1 nuclear localization. Thus, these simple scaffolds link the activation of diverse RAS family small G proteins to Hippo or p53 regulation.
  65. J Exp Med. 2021 Jan 04. pii: e20182232. [Epub ahead of print]218(1):
    Tan CL, Kuchroo JR, Sage PT, Liang D, Francisco LM, Buck J, Thaker YR, Zhang Q, McArdel SL, Juneja VR, Lee SJ, Lovitch SB, Lian C, Murphy GF, Blazar BR, Vignali DAA, Freeman GJ, Sharpe AH.
      Inhibitory signals through the PD-1 pathway regulate T cell activation, T cell tolerance, and T cell exhaustion. Studies of PD-1 function have focused primarily on effector T cells. Far less is known about PD-1 function in regulatory T (T reg) cells. To study the role of PD-1 in T reg cells, we generated mice that selectively lack PD-1 in T reg cells. PD-1-deficient T reg cells exhibit an activated phenotype and enhanced immunosuppressive function. The in vivo significance of the potent suppressive capacity of PD-1-deficient T reg cells is illustrated by ameliorated experimental autoimmune encephalomyelitis (EAE) and protection from diabetes in nonobese diabetic (NOD) mice lacking PD-1 selectively in T reg cells. We identified reduced signaling through the PI3K-AKT pathway as a mechanism underlying the enhanced suppressive capacity of PD-1-deficient T reg cells. Our findings demonstrate that cell-intrinsic PD-1 restraint of T reg cells is a significant mechanism by which PD-1 inhibitory signals regulate T cell tolerance and autoimmunity.
  66. J Clin Med. 2020 Oct 13. pii: E3283. [Epub ahead of print]9(10):
    Allen J, Cernik C, Bajwa S, Al-Rajabi R, Saeed A, Baranda J, Williamson S, Sun W, Kasi A.
      We examined the relationship between the daily rate of change of cancer antigen 19-9 (CA19-9) over the first 90 days of treatment (DRC90) and the pretreatment levels of neutrophils, lymphocytes, and platelets with the overall survival (OS) and progression-free survival (PFS) in patients with stage IV pancreatic ductal adenocarcinoma (PDA) who received chemotherapy. We retrospectively evaluated 102 locally advanced and metastatic PDA patients treated at the University of Kansas Cancer Center (KUCC) between January 2011 and September 2019. We compared the ratio of the pretreatment absolute neutrophil count to the pretreatment absolute lymphocyte count (NLR) and the ratio between the pretreatment platelet count to the pretreatment absolute lymphocyte count (PLR) with the OS and PFS. We compared the DRC90 to the OS and PFS. The ratios were analyzed using the log-rank trend test using the mean of the NLR, PLR, and DRC90 as the threshold for two groups within each variable. Patients with ≥mean NLR (4.6 K/µL) had a significantly lower OS (p = 0.0444) and PFS (p = 0.0483) compared with patients below the mean. Patients with PLR ≥ mean (3.9 K/µL) did not have a significantly different OS (p = 0.507) or PFS (p = 0.643) compared with patients below the mean. Patients with DRC90 ≥ mean (-1%) did not have a significantly different OS (p = 0.342) or PFS (p = 0.313) compared with patients below the mean. Patients with NLR ≥ mean (4.6 K/µL) had a significantly lower OS and PFS compared with patients with NLR below the mean. This implies the possibility of NLR as a prognostic marker in PDA that could guide treatment approaches but still requires validation in a larger cohort.
    Keywords:  pancreatic cancer; pancreatic cancer prognosis; pancreatic ductal adenocarcinoma
  67. Curr Osteoporos Rep. 2020 Oct 12.
    Zhong X, Zimmers TA.
      PURPOSE OF REVIEW: Cachexia, a feature of cancer and other chronic diseases, is marked by progressive weight loss and skeletal muscle wasting. This review aims to highlight the sex differences in manifestations of cancer cachexia in patients, rodent models, and our current understanding of the potential mechanisms accounting for these differences.RECENT FINDINGS: Male cancer patients generally have higher prevalence of cachexia, greater weight loss or muscle wasting, and worse outcomes compared with female cancer patients. Knowledge is increasing about sex differences in muscle fiber type and function, mitochondrial metabolism, global gene expression and signaling pathways, and regulatory mechanisms at the levels of sex chromosomes vs. sex hormones; however, it is largely undetermined how such sex differences directly affect the susceptibility to stressors leading to muscle wasting in cancer cachexia. Few studies have investigated basic mechanisms underlying sex differences in cancer cachexia. A better understanding of sex differences would improve cachexia treatment in both sexes.
    Keywords:  Animals; Cachexia/etiology; Cachexia/pathology; Humans; Neoplasms/complications; Sex characteristics
  68. Lancet. 2020 10 10. pii: S0140-6736(20)32111-5. [Epub ahead of print]396(10257): 1058
    Burki T.
  69. Biogerontology. 2020 Oct 16.
    Kobayashi H, Martínez de Toda I, Sanz-San Miguel L, De la Fuente M.
      Finding biomarkers to assess the rate of ageing and consequently, to forecast individual lifespan is a challenge in ageing research. We recently published a mathematical model for lifespan prediction in adult female mice using behavioural parameters such as internal locomotion and time spent in open arms in the hole board (HB) and elevated plus maze (EPM) tests, respectively. Nevertheless, it is still not known if these behavioural variables could be useful in forecasting lifespan in male mice. Therefore, two groups of ICR-CD1 mice, male and female were subjected to the EPM, HB and T-maze tests at the adult age. Mice were monitored until they died and individual lifespans were registered. In general, adult male mice showed more anxiety-like behaviours than females. The mathematical model previously developed in females was validated with the female cohort, but found to be suboptimal for lifespan prediction in males. Thus, a new model for male lifespan prediction was constructed including the behavioural variables that were predictive of lifespan in males: time in the central platform of the EPM, inner locomotion, number of groomings and number and duration of head-dippings in the HB. These results confirm that the higher the anxiety-like behaviour at the adult age, the shorter the lifespan.
    Keywords:  Anxiety and exploratory behaviour; Lifespan prediction; Male and female mice behaviour; Multiple lineal regression
  70. Mol Cell. 2020 Oct 15. pii: S1097-2765(20)30657-2. [Epub ahead of print]80(2): 279-295.e8
    Yip HYK, Chee A, Ang CS, Shin SY, Ooms LM, Mohammadi Z, Phillips WA, Daly RJ, Cole TJ, Bronson RT, Nguyen LK, Tiganis T, Hobbs RM, McLean CA, Mitchell CA, Papa A.
      The PTEN tumor suppressor controls cell death and survival by regulating functions of various molecular targets. While the role of PTEN lipid-phosphatase activity on PtdIns(3,4,5)P3 and inhibition of PI3K pathway is well characterized, the biological relevance of PTEN protein-phosphatase activity remains undefined. Here, using knockin (KI) mice harboring cancer-associated and functionally relevant missense mutations, we show that although loss of PTEN lipid-phosphatase function cooperates with oncogenic PI3K to promote rapid mammary tumorigenesis, the additional loss of PTEN protein-phosphatase activity triggered an extensive cell death response evident in early and advanced mammary tumors. Omics and drug-targeting studies revealed that PI3Ks act to reduce glucocorticoid receptor (GR) levels, which are rescued by loss of PTEN protein-phosphatase activity to restrain cell survival. Thus, we find that the dual regulation of GR by PI3K and PTEN functions as a rheostat that can be exploited for the treatment of PTEN loss-driven cancers.
    Keywords:  failsafe mechanism
  71. Cell. 2020 Oct 13. pii: S0092-8674(20)31158-2. [Epub ahead of print]
    Wang L, Sinnott-Armstrong N, Wagschal A, Wark AR, Camporez JP, Perry RJ, Ji F, Sohn Y, Oh J, Wu S, Chery J, Moud BN, Saadat A, Dankel SN, Mellgren G, Tallapragada DSP, Strobel SM, Lee MJ, Tewhey R, Sabeti PC, Schaefer A, Petri A, Kauppinen S, Chung RT, Soukas A, Avruch J, Fried SK, Hauner H, Sadreyev RI, Shulman GI, Claussnitzer M, Näär AM.
      Positive selection in Europeans at the 2q21.3 locus harboring the lactase gene has been attributed to selection for the ability of adults to digest milk to survive famine in ancient times. However, the 2q21.3 locus is also associated with obesity and type 2 diabetes in humans, raising the possibility that additional genetic elements in the locus may have contributed to evolutionary adaptation to famine by promoting energy storage, but which now confer susceptibility to metabolic diseases. We show here that the miR-128-1 microRNA, located at the center of the positively selected locus, represents a crucial metabolic regulator in mammals. Antisense targeting and genetic ablation of miR-128-1 in mouse metabolic disease models result in increased energy expenditure and amelioration of high-fat-diet-induced obesity and markedly improved glucose tolerance. A thrifty phenotype connected to miR-128-1-dependent energy storage may link ancient adaptation to famine and modern metabolic maladaptation associated with nutritional overabundance.
  72. Sci Adv. 2020 Oct;pii: eaaz4530. [Epub ahead of print]6(42):
    Aiello I, Fedele MLM, Román F, Marpegan L, Caldart C, Chiesa JJ, Golombek DA, Finkielstein CV, Paladino N.
      Circadian disruption negatively affects physiology, posing a global health threat that manifests in proliferative, metabolic, and immune diseases, among others. Because outputs of the circadian clock regulate daily fluctuations in the immune response, we determined whether circadian disruption results in tumor-associated immune cell remodeling, facilitating tumor growth. Our findings show that tumor growth rate increased and latency decreased under circadian disruption conditions compared to normal light-dark (LD) schedules in a murine melanoma model. Circadian disruption induced the loss or inversion of daily patterns of M1 (proinflammatory) and M2 (anti-inflammatory) macrophages and cytokine levels in spleen and tumor tissues. Circadian disruption also induced (i) deregulation of rhythmic expression of clock genes and (ii) of cyclin genes in the liver, (iii) increased CcnA2 levels in the tumor, and (iv) dampened expression of the cell cycle inhibitor p21WAF/CIP1 , all of which contribute to a proliferative phenotype.
  73. Nature. 2020 Oct 14.
    Marshall KL, Saade D, Ghitani N, Coombs AM, Szczot M, Keller J, Ogata T, Daou I, Stowers LT, Bönnemann CG, Chesler AT, Patapoutian A.
      Henry Miller stated that "to relieve a full bladder is one of the great human joys". Urination is critically important in health and ailments of the lower urinary tract cause high pathological burden. Although there have been advances in understanding the central circuitry in the brain that facilitates urination1-3, there is a lack of in-depth mechanistic insight into the process. In addition to central control, micturition reflexes that govern urination are all initiated by peripheral mechanical stimuli such as bladder stretch and urethral flow4. The mechanotransduction molecules and cell types that function as the primary stretch and pressure detectors in the urinary tract mostly remain unknown. Here we identify expression of the mechanosensitive ion channel PIEZO2 in lower urinary tract tissues, where it is required for low-threshold bladder-stretch sensing and urethral micturition reflexes. We show that PIEZO2 acts as a sensor in both the bladder urothelium and innervating sensory neurons. Humans and mice lacking functional PIEZO2 have impaired bladder control, and humans lacking functional PIEZO2 report deficient bladder-filling sensation. This study identifies PIEZO2 as a key mechanosensor in urinary function. These findings set the foundation for future work to identify the interactions between urothelial cells and sensory neurons that control urination.
  74. Nat Rev Immunol. 2020 Oct 14.
    Ribot JC, Lopes N, Silva-Santos B.
      γδ T cells are a unique T cell subpopulation that are rare in secondary lymphoid organs but enriched in many peripheral tissues, such as the skin, intestines and lungs. By rapidly producing large amounts of cytokines, γδ T cells make key contributions to immune responses in these tissues. In addition to their immune surveillance activities, recent reports have unravelled exciting new roles for γδ T cells in steady-state tissue physiology, with functions ranging from the regulation of thermogenesis in adipose tissue to the control of neuronal synaptic plasticity in the central nervous system. Here, we review the roles of γδ T cells in tissue homeostasis and in surveillance of infection, aiming to illustrate their major impact on tissue integrity, tissue repair and immune protection.
  75. PLoS Genet. 2020 Oct 15. 16(10): e1009069
    Hammerle CM, Sandovici I, Brierley GV, Smith NM, Zimmer WE, Zvetkova I, Prosser HM, Sekita Y, Lam BYH, Ma M, Cooper WN, Vidal-Puig A, Ozanne SE, Medina-Gómez G, Constância M.
      The genetic mechanisms that determine the size of the adult pancreas are poorly understood. Imprinted genes, which are expressed in a parent-of-origin-specific manner, are known to have important roles in development, growth and metabolism. However, our knowledge regarding their roles in the control of pancreatic growth and function remains limited. Here we show that many imprinted genes are highly expressed in pancreatic mesenchyme-derived cells and explore the role of the paternally-expressed insulin-like growth factor 2 (Igf2) gene in mesenchymal and epithelial pancreatic lineages using a newly developed conditional Igf2 mouse model. Mesenchyme-specific Igf2 deletion results in acinar and beta-cell hypoplasia, postnatal whole-body growth restriction and maternal glucose intolerance during pregnancy, suggesting that the mesenchyme is a developmental reservoir of IGF2 used for paracrine signalling. The unique actions of mesenchymal IGF2 are demonstrated by the absence of any discernible growth or functional phenotypes upon Igf2 deletion in the developing pancreatic epithelium. Additionally, increased IGF2 levels specifically in the mesenchyme, through conditional Igf2 loss-of-imprinting or Igf2r deletion, leads to pancreatic acinar overgrowth. Furthermore, ex-vivo exposure of primary acinar cells to exogenous IGF2 activates AKT, a key signalling node, and increases their number and amylase production. Based on these findings, we propose that mesenchymal Igf2, and perhaps other imprinted genes, are key developmental regulators of adult pancreas size and function.
  76. Autophagy. 2020 Oct 15. 1-3
    Santovito D, Egea V, Bidzhekov K, Natarelli L, Mourão A, Blanchet X, Wichapong K, Aslani M, Brunßen C, Horckmans M, Hristov M, Geerlof A, Lutgens E, Daemen MJAP, Hackeng T, Ries C, Chavakis T, Morawietz H, Naumann R, Hundelshausen PV, Steffens S, Duchêne J, Megens RTA, Sattler M, Weber C.
      MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression which act by guiding AGO (argonaute) proteins to target RNA transcripts in the RNA-induced silencing complex (RISC). This macromolecular complex includes multiple additional components (e.g., TNRC6A) that allow for interaction with enzymes mediating inhibition of translation or RNA decay. However, miRNAs also reside in low-molecular weight complexes without being engaged in target repression, and their function in this context is largely unknown. Our recent findings show that endothelial cells exposed to protective high-shear stress or MTORC inhibition activate the macroautophagy/autophagy machinery to sustain viability by promoting differential trafficking of MIR126 strands and by enabling unconventional features of MIR126-5p. Whereas MIR126-3p is degraded upon autophagy activation, MIR126-5p interacts with the RNA-binding protein MEX3A to form a ternary complex with AGO2. This complex forms on the autophagosomal surface and facilitates its nuclear localization. Once in the nucleus, MIR126-5p dissociates from AGO2 and establishes aptamer-like interactions with the effector CASP3 (caspase 3). The binding to MIR126-5p prevents dimerization and proper active site formation of CASP3, thus inhibiting proteolytic activity and limiting apoptosis. Disrupting this pathway in vivo by genetic deletion of Mex3a or by specific deficiency of endothelial autophagy aggravates endothelial apoptosis and exacerbates the progression of atherosclerosis. The direct inhibition of CASP3 by MIR126-5p reveals a non-canonical mechanism by which miRNAs can modulate protein function and mediate the autophagy-apoptosis crosstalk.
    Keywords:  Atherosclerosis; Autophagy; Endothelial cells; MEX3A; Noncanonical miRNA functions; miR-126-5p; microRNA
  77. Proc Natl Acad Sci U S A. 2020 Oct 15. pii: 202010872. [Epub ahead of print]
    Chrisafis G, Wang T, Moissoglu K, Gasparski AN, Ng Y, Weigert R, Lockett SJ, Mili S.
      Localization of RNAs at protrusive regions of cells is important for single-cell migration on two-dimensional surfaces. Protrusion-enriched RNAs encode factors linked to cancer progression, such as the RAB13 GTPase and the NET1 guanine nucleotide exchange factor, and are regulated by the tumor-suppressor protein APC. However, tumor cells in vivo often do not move as single cells but rather utilize collective modes of invasion and dissemination. Here, we developed an inducible system of three-dimensional (3D) collective invasion to study the behavior and importance of protrusion-enriched RNAs. We find that, strikingly, both the RAB13 and NET1 RNAs are enriched specifically at the invasive front of leader cells in invasive cell strands. This localization requires microtubules and coincides with sites of high laminin concentration. Indeed, laminin association and integrin engagement are required for RNA accumulation at the invasive front. Importantly, perturbing RNA accumulation reduces collective 3D invasion. Examination of in vivo tumors reveals a similar localization of the RAB13 and NET1 RNAs at potential invasive sites, suggesting that this mechanism could provide a targeting opportunity for interfering with collective cancer cell invasion.
    Keywords:  NET1; RAB13; RNA localization; antisense oligo; collective invasion
  78. Cancer Causes Control. 2020 Oct 16.
    Boursi B, Huber JS, Haynes K, Mamtani R, Yang YX.
      PURPOSE: Digoxin affects several cellular pathways involved in tumorigenesis. We sought to determine the association between digoxin use and pancreatic cancer risk and survival.METHODS: A nested case-control study using The Health Improvement Network (THIN), a population-representative database from the United Kingdom (UK). Cases included all individuals with incident diagnosis of pancreatic cancer. Each case was matched to up to four controls using incidence density sampling based on age, sex, practice site, calendar time, and duration of follow-up. Exposure of interest was digoxin therapy before cancer diagnosis. Odds ratios (ORs) and 95% confidence intervals (CIs) for the association between digoxin use and pancreatic cancer risk were estimated using conditional logistic regression. We further conducted a retrospective cohort study among pancreatic cancer cases using Cox regression model in order to evaluate the association between digoxin use and overall survival.
    RESULTS: We identified 4,113 cases with incident pancreatic cancer and 16,072 matched controls. The adjusted OR for diagnosis of pancreatic cancer among active digoxin users was 1.41 (95% CI 1.16-1.72). The risk did not change among active users with duration of therapy of more than 1 year (adjusted OR of 1.39, 95% CI 1.11-1.76). Digoxin was not associated with change in overall survival with an adjusted hazard ratio of 0.97 (95% CI 0.81-1.18).
    CONCLUSIONS: Digoxin use was associated with modestly increased pancreatic cancer risk but did not affect overall survival.
    Keywords:  Cancer survival; Digoxin; Pancreatic cancer