bims-auttor Biomed News
on Autophagy and mTOR
Issue of 2024‒03‒24
fifty-six papers selected by
Viktor Korolchuk, Newcastle University
  1. Zebrafish raptor mutation inhibits the activity of mTORC1, inducing craniofacial defects due to autophagy-induced neural crest cell death.
  2. CASM mediates LRRK2 recruitment and activation under lysosomal stress.
  3. G protein-coupled receptor-mediated autophagy in health and disease.
  4. Alternative autophagy dampens UVB-induced NLRP3 inflammasome activation in human keratinocytes.
  5. Lysosomal cystine accumulation activates mTOR signaling in cystinosis: are mTOR inhibitors the cure?
  6. CSNK2/CK2 regulates selective autophagy of the endoplasmic reticulum.
  7. Quadriceps muscle atrophy after non-invasive anterior cruciate ligament injury: evidence linking to autophagy and mitophagy.
  8. The association between ferroptosis and autophagy in cardiovascular diseases.
  9. Biosensors; a novel concept in real-time detection of autophagy.
  10. Identification of membrane curvature sensing motifs essential for VPS37A phagophore recruitment and autophagosome closure.
  11. An evolutionary mechanism to assimilate new nutrient sensors into the mTORC1 pathway.
  12. Mitochondria-lysosome-extracellular vesicles axis and nanotheranostics in neurodegenerative diseases.
  13. Reduced Cx43 Expression Induces Autophagy through Activation of the AMPK-mTOR-ULK1 Signaling Pathway in the Common Bile Duct Ligation Rat Heart.
  14. AMPK and insulin control the switch between mitochondrial hitchhiking of Pink1 mRNA and mitophagy in neurons.
  15. Foot-and-mouth disease virus VP1 degrades YTHDF2 through autophagy to regulate IRF3 activity for viral replication.
  16. A partial Drp1 knockout improves autophagy flux independent of mitochondrial function.
  17. Evaluation of Autophagy in Conjunctival Fibroblasts.
  18. The SCF-FBW7β E3 ligase mediates ubiquitination and degradation of the serine/threonine protein kinase PINK1.
  19. Lysosomal damage sensing and lysophagy initiation by SPG20-ITCH.
  20. Interplay of mitochondria associated membrane proteins and autophagy: Implications in neurodegeneration.
  21. Traditional Chinese medicine and its active substances reduce vascular injury in diabetes via regulating autophagic activity.
  22. Insulin signalling regulates Pink1 mRNA localization via modulation of AMPK activity to support PINK1 function in neurons.
  23. Ferritinophagy Is Critical for Deoxynivalenol-Induced Liver Injury in Mice.
  24. miR-218-5p and doxorubicin combination enhances anticancer activity in breast cancer cells through Parkin-dependent mitophagy inhibition.
  25. The activation mechanism of Atg15, a vacuolar phospholipase required for the disintegration of organelle membranes.
  26. Cell non-autonomous control of autophagy and metabolism by glial cells.
  27. Arabidopsis BECLIN1-induced autophagy mediates reprogramming in tapetal programmed cell death by altering the gross cellular homeostasis.
  28. Emerging dimensions of autophagy in melanoma.
  29. MoMkk1 and MoAtg1 dichotomously regulating autophagy and pathogenicity through MoAtg9 phosphorylation in Magnaporthe oryzae.
  30. Scd1 and monounsaturated lipids are required for autophagy and survival of adipocytes.
  31. mTORC1 is required for differentiation of germline stem cells in the Drosophila melanogaster testis.
  32. mTOR hyperactivity and RICTOR amplification as targets for personalized treatments in malignancies.
  33. Role of Raptor Gene Variants in Hypertension: Influence on Blood Pressure Independent of Salt Intake in White Population.
  34. The interaction between lncRNAs and transcription factors regulating autophagy in human cancers: A comprehensive and therapeutical survey.
  35. Autophagy Induced by Low Shear Stress Leads to Endothelial Glycocalyx Disruption.
  36. Up-regulation of cholesterol synthesis by lysosomal defects requires a functional mitochondrial respiratory chain.
  37. Autophagy regulates the maturation of hematopoietic precursors in the embryo.
  38. Hepatic nutrient and hormone signaling to mTORC1 instructs the postnatal metabolic zonation of the liver.
  39. Streptococcus pneumoniae extracellular vesicles aggravate alveolar epithelial barrier disruption via autophagic degradation of OCLN (occludin).
  40. AMPK/MTOR/TP53 Signaling Pathway Regulation by Calcitonin Gene-Related Peptide Reduces Oxygen-Induced Lung Damage in Neonatal Rats through Autophagy Promotion.
  41. MALT-1 shortens lifespan by inhibiting autophagy in the intestine of C. elegans.
  42. Expression of ALS-PFN1 impairs vesicular degradation in iPSC-derived microglia.
  43. The regulatory role of miRNA and lncRNA on autophagy in diabetic nephropathy.
  44. Ischemia-induced cardiac dysfunction is exacerbated in adiponectin-knockout mice due to impaired autophagy flux.
  45. Ectopic HCN4 Provides a Target Biomarker for the Genetic Spectrum of mTORopathies.
  46. YME1L-mediated mitophagy protects renal tubular cells against cellular senescence under diabetic conditions.
  47. Emerging roles of TBK1 in cancer immunobiology.
  48. Dual-specificity kinase DYRK3 phosphorylates p62 at the Thr-269 residue and promotes melanoma progression.
  49. PLEKHM2 deficiency induces impaired mitochondrial clearance and elevated ROS levels in human iPSC-derived cardiomyocytes.
  50. The roles of autophagy, ferroptosis and pyroptosis in the anti-ovarian cancer mechanism of harmine and their crosstalk.
  51. Autophagy inhibition potentiates energy restriction-induced cell death in hepatocellular carcinoma cells.
  52. Integrating the response to stressed mitochondria.
  53. A TBK1 variant causes autophagolysosomal and motoneuron pathology without neuroinflammation in mice.
  54. Association between serum beclin 1 level and cardiac valvular calcification in hemodialysis patients.
  55. Retinoblastoma-associated protein is important for TRIM24-mediated activation of the mTOR signaling pathway through DUSP2 action in prostate cancer.
  56. A pH-Sensitive Double Chromophore Fluorescent Dye for Live-Tracking of Lipophagy.
  1. Development. 2024 Mar 15. pii: dev202216. [Epub ahead of print]151(6):
    Zebrafish raptor mutation inhibits the activity of mTORC1, inducing craniofacial defects due to autophagy-induced neural crest cell death.
    Scott K Tucker, Ritika Gosul, Mary E Swartz, Stephanie Zhang, Johann K Eberhart.
      The mechanistic target of rapamycin (mTOR) coordinates metabolism and cell growth with environmental inputs. mTOR forms two functional complexes: mTORC1 and mTORC2. Proper development requires both complexes but mTORC1 has unique roles in numerous cellular processes, including cell growth, survival and autophagy. Here, we investigate the function of mTORC1 in craniofacial development. We created a zebrafish raptor mutant via CRISPR/Cas9, to specifically disrupt mTORC1. The entire craniofacial skeleton and eyes were reduced in size in mutants; however, overall body length and developmental timing were not affected. The craniofacial phenotype associates with decreased chondrocyte size and increased neural crest cell death. We found that autophagy is elevated in raptor mutants. Chemical inhibition of autophagy reduced cell death and improved craniofacial phenotypes in raptor mutants. Genetic inhibition of autophagy, via mutation of the autophagy gene atg7, improved facial phenotypes in atg7;raptor double mutants, relative to raptor single mutants. We conclude that finely regulated levels of autophagy, via mTORC1, are crucial for craniofacial development.
    Keywords:  Autophagy; Cell death; Craniofacial; MTOR; Neural crest; Zebrafish
    DOI:  https://doi.org/10.1242/dev.202216
  2. Autophagy. 2024 Mar 21. 1-2
    CASM mediates LRRK2 recruitment and activation under lysosomal stress.
    Tomoki Kuwahara, Takeshi Iwatsubo.
      Conjugation of ATG8 to single membranes (CASM) at endolysosomal compartments has attracted attention as the non-autophagic function of the Atg8-family protein conjugation system, and the V-ATPase-ATG16L1 axis has emerged as a core mechanism. Our recent research has revealed that this mechanism contributes to the lysosomal recruitment and activation of LRRK2, a Parkinson disease-associated kinase that phosphorylates a subset of RAB GTPases. The activated LRRK2 under CASM-causing lysosomal stress acts to regulate lysosomal morphology and stimulate extracellular secretion of lysosomal contents, thereby promoting the lysosomal stress response.
    Keywords:  ATG8 conjugation system; CASM; LAP; LRRK2; V-ATPase-ATG16L1 axis; lysosome
    DOI:  https://doi.org/10.1080/15548627.2024.2330032
  3. Br J Pharmacol. 2024 Mar 19.
    G protein-coupled receptor-mediated autophagy in health and disease.
    Devrim Öz-Arslan, Zeynep Aslıhan Durer, Beki Kan.
      G protein-coupled receptors (GPCRs) constitute the largest and most diverse superfamily of mammalian transmembrane proteins. These receptors are involved in a wide range of physiological functions and are targets for more than a third of available drugs in the market. Autophagy is a cellular process involved in degrading damaged proteins and organelles and in recycling cellular components. Deficiencies in autophagy are involved in a variety of pathological conditions. Both GPCRs and autophagy are essential in preserving homeostasis and cell survival. There is emerging evidence suggesting that GPCRs are direct regulators of autophagy. Additionally, autophagic machinery is involved in the regulation of GPCR signalling. The interplay between GPCR and autophagic signalling mechanisms significantly impacts on health and disease; however, there is still an incomplete understanding of the underlying mechanisms and therapeutic implications in different tissues and disease contexts. This review aims to discuss the interactions between GPCR and autophagy signalling. Studies on muscarinic receptors, beta-adrenoceptors, taste receptors, purinergic receptors and adhesion GPCRs are summarized, in relation to autophagy.
    Keywords:  G protein-coupled receptors; autophagy; disease; signalling
    DOI:  https://doi.org/10.1111/bph.16345
  4. J Biol Chem. 2024 Mar 16. pii: S0021-9258(24)01668-5. [Epub ahead of print] 107173
    Alternative autophagy dampens UVB-induced NLRP3 inflammasome activation in human keratinocytes.
    Tatsuya Hasegawa, Saori Noguchi, Masaya Nakashima, Masashi Miyai, Makiko Goto, Yuko Matsumoto, Satoru Torii, Shinya Honda, Shigeomi Shimizu.
      Sunlight exposure results in an inflammatory reaction of the skin commonly known as sunburn, which increases skin cancer risk. In particular, the ultraviolet B (UVB) component of sunlight induces inflammasome activation in keratinocytes to instigate the cutaneous inflammatory responses. Here, we explore the intracellular machinery that maintains skin homeostasis by suppressing UVB-induced inflammasome activation in human keratinocytes. We found that pharmacological inhibition of autophagy promoted UVB-induced NLRP3 inflammasome activation. Unexpectedly, however, gene silencing of Atg5 or Atg7, which are critical for conventional autophagy, had no effect, whereas gene silencing of Beclin1, which is essential not only for conventional autophagy but also for Atg5/Atg7-independent alternative autophagy, promoted UVB-induced inflammasome activation, indicating an involvement of alternative autophagy. We found that damaged mitochondria were highly accumulated in UVB-irradiated keratinocytes when alternative autophagy was inhibited, and they appear to be recognized by NLRP3. Overall, our findings indicate that alternative autophagy, rather than conventional autophagy, suppresses UVB-induced NLRP3 inflammasome activation through the clearance of damaged mitochondria in human keratinocytes, and illustrate a previously unknown involvement of alternative autophagy in inflammation. Alternative autophagy may be a new therapeutic target for sunburn and associated cutaneous disorders.
    Keywords:  Alternative autophagy; Inflammasome; Keratinocyte; Skin; Sunburn
    DOI:  https://doi.org/10.1016/j.jbc.2024.107173
  5. Kidney Int. 2024 Apr;pii: S0085-2538(23)00913-4. [Epub ahead of print]105(4): 656-658
    Lysosomal cystine accumulation activates mTOR signaling in cystinosis: are mTOR inhibitors the cure?
    Salómon Christer, Matias Simons.
      
    Keywords:  Fanconi syndrome; cystine; lysosomes; mTOR signaling; proximal tubular cells
    DOI:  https://doi.org/10.1016/j.kint.2023.11.030
  6. Autophagy. 2024 Mar 21. 1-2
    CSNK2/CK2 regulates selective autophagy of the endoplasmic reticulum.
    Alexandra Stolz.
      Tuning and assimilation of endoplasmic reticulum (ER) content in each cell of the human body is an essential part of organismal homeostasis and adaptation to stress. As such, the lysosomal turnover of ER (reticulophagy) needs to be regulated in a spatio-temporal as well as cell-type specific manner. We recently identified CSNK2/CK2 (casein kinase 2) as the enzyme that phosphorylates the reticulophagy receptors RETREG1/FAM134B and RETREG3/FAM134C and regulates their activity. Phosphorylation of the receptors is a prerequisite for their subsequent functional ubiquitination and the formation of high-density clusters, presumably representing active macroautophagy/autophagy sites at the ER membrane. Consistently, treatment with kinase inhibitor SGC-CK2-1, knockdown of endogenous CSNK2, or mutation of respective phospho-sites prevents ubiquitination, the formation of high-density clusters as well as reticulophagy flux. We hypothesize that CSNK2 has a broader impact on ER and Golgi content in a cell-type and context-specific manner by orchestrating the activity of several autophagy receptors and potentially also factors of the ER-associated protein degradation pathway.
    Keywords:  ER-phagy; kinase; kinase signaling; organelle turnover; phosphorylation; ubiquitination
    DOI:  https://doi.org/10.1080/15548627.2024.2330037
  7. Front Physiol. 2024 ;15 1341723
    Quadriceps muscle atrophy after non-invasive anterior cruciate ligament injury: evidence linking to autophagy and mitophagy.
    Sung Gi Noh, Ahram Ahn, Steven M Davi, Lindsey K Lepley, Oh Sung Kwon.
      Introduction: Anterior cruciate ligament (ACL) injury is frequently accompanied by quadriceps muscle atrophy, a process closely linked to mitochondrial health and mitochondria-specific autophagy. However, the temporal progression of key quadricep atrophy-mediating events following ACL injury remains poorly understood. To advance our understanding, we conducted a longitudinal study to elucidate key parameters in quadriceps autophagy and mitophagy. Methods: Long-Evans rats were euthanized at 7, 14, 28, and 56 days after non-invasive ACL injury that was induced via tibial compression overload; controls were not injured. Vastus lateralis muscle was extracted, and subsequent immunoblotting analysis was conducted using primary antibodies targeting key proteins involved in autophagy and mitophagy cellular processes. Results: Our findings demonstrated dynamic changes in autophagy and mitophagy markers in the quadriceps muscle during the recovery period after ACL injury. The early response to the injury was characterized by the induction of autophagy at 14 days (Beclin1), indicating an initial cellular response to the injury. Subsequently, at 14 days we observed increase in the elongation of autophagosomes (Atg4B), suggesting a potential remodeling process. The autophagosome flux was also augmented between 14- and 28 days (LC3-II/LC3-I ratio and p62). Notably, at 56 days, markers associated with the elimination of damaged mitochondria were elevated (PINK1, Parkin, and VDAC1), indicating a possible ongoing cellular repair and restoration process. Conclusion: These data highlight the complexity of muscle recovery after ACL injury and underscore the overlooked but crucial role of autophagy and mitophagy in promoting the recovery process.
    Keywords:  ACL injury; autophagy; mitophagy; muscle atrophy; vastus lateralis muscle
    DOI:  https://doi.org/10.3389/fphys.2024.1341723
  8. Cell Biochem Funct. 2024 Mar;42(2): e3985
    The association between ferroptosis and autophagy in cardiovascular diseases.
    Yifan Zhang, Junjun Yang, Chenxi Ouyang, Ning Meng.
      Autophagy is a process in which cells degrade intracellular substances and play a variety of roles in cells, such as maintaining intracellular homeostasis, preventing cell overgrowth, and removing pathogens. It is highly conserved during the evolution of eukaryotic cells. So far, the study of autophagy is still a hot topic in the field of cytology. Ferroptosis is an iron-dependent form of cell death, accompanied by the accumulation of reactive oxygen species and lipid peroxides. With the deepening of research, it has been found that ferroptosis, like autophagy, is involved in the occurrence and development of cardiovascular diseases. The relationship between autophagy and ferroptosis is complex, and the association between the two in cardiovascular disease remains to be clarified. This article reviews the mechanism of autophagy and ferroptosis and their correlation, and discusses the relationship between them in cardiovascular diseases, which is expected to provide new and important treatment strategies for cardiovascular diseases.
    Keywords:  autophagy; cardiovascular disease; cytoplasm; ferroptosis; lipid peroxide
    DOI:  https://doi.org/10.1002/cbf.3985
  9. Biosens Bioelectron. 2024 Mar 16. pii: S0956-5663(24)00209-4. [Epub ahead of print]254 116204
    Biosensors; a novel concept in real-time detection of autophagy.
    Hassan Nasrollahpour, Arezoo Mirzaie, Maryam Sharifi, Aysa Rezabakhsh, Balal Khalilzadeh, Reza Rahbarghazi, Hadi Yousefi, Daniel J Klionsky.
      Autophagy is an early-stage response with self-degradation properties against several insulting conditions. To date, the critical role of autophagy has been well-documented in physiological and pathological conditions. This process involves various signaling and functional biomolecules, which are involved in different steps of the autophagic response. During recent decades, a range of biochemical analyses, chemical assays, and varied imaging techniques have been used for monitoring this pathway. Due to the complexity and dynamic aspects of autophagy, the application of the conventional methodology for following autophagic progression is frequently associated with a mistake in discrimination between a complete and incomplete autophagic response. Biosensors provide a de novo platform for precise and accurate analysis of target molecules in different biological settings. It has been suggested that these devices are applicable for real-time monitoring and highly sensitive detection of autophagy effectors. In this review article, we focus on cutting-edge biosensing technologies associated with autophagy detection.
    Keywords:  Autophagy; Biosensors; Real-time and sensitive detection; Theranostics
    DOI:  https://doi.org/10.1016/j.bios.2024.116204
  10. Commun Biol. 2024 Mar 15. 7(1): 334
    Identification of membrane curvature sensing motifs essential for VPS37A phagophore recruitment and autophagosome closure.
    Yansheng Ye, Xinwen Liang, Guifang Wang, Maria C Bewley, Kouta Hamamoto, Xiaoming Liu, John M Flanagan, Hong-Gang Wang, Yoshinori Takahashi, Fang Tian.
      VPS37A, an ESCRT-I complex component, is required for recruiting a subset of ESCRT proteins to the phagophore for autophagosome closure. However, the mechanism by which VPS37A is targeted to the phagophore remains obscure. Here, we demonstrate that the VPS37A N-terminal domain exhibits selective interactions with highly curved membranes, mediated by two membrane-interacting motifs within the disordered regions surrounding its Ubiquitin E2 variant-like (UEVL) domain. Site-directed mutations of residues in these motifs disrupt ESCRT-I localization to the phagophore and result in defective phagophore closure and compromised autophagic flux in vivo, highlighting their essential role during autophagy. In conjunction with the UEVL domain, we postulate that these motifs guide a functional assembly of the ESCRT machinery at the highly curved tip of the phagophore for autophagosome closure. These results advance the notion that the distinctive membrane architecture of the cup-shaped phagophore spatially regulates autophagosome biogenesis.
    DOI:  https://doi.org/10.1038/s42003-024-06026-7
  11. Nat Commun. 2024 Mar 21. 15(1): 2517
    An evolutionary mechanism to assimilate new nutrient sensors into the mTORC1 pathway.
    Grace Y Liu, Patrick Jouandin, Raymond E Bahng, Norbert Perrimon, David M Sabatini.
      Animals sense and respond to nutrient availability in their environments, a task coordinated in part by the mTOR complex 1 (mTORC1) pathway. mTORC1 regulates growth in response to nutrients and, in mammals, senses specific amino acids through specialized sensors that bind the GATOR1/2 signaling hub. Given that animals can occupy diverse niches, we hypothesized that the pathway might evolve distinct sensors in different metazoan phyla. Whether such customization occurs, and how the mTORC1 pathway might capture new inputs, is unknown. Here, we identify the Drosophila melanogaster protein Unmet expectations (CG11596) as a species-restricted methionine sensor that directly binds the fly GATOR2 complex in a fashion antagonized by S-adenosylmethionine (SAM). We find that in Dipterans GATOR2 rapidly evolved the capacity to bind Unmet and to thereby repurpose a previously independent methyltransferase as a SAM sensor. Thus, the modular architecture of the mTORC1 pathway allows it to co-opt preexisting enzymes to expand its nutrient sensing capabilities, revealing a mechanism for conferring evolvability on an otherwise conserved system.
    DOI:  https://doi.org/10.1038/s41467-024-46680-3
  12. Exp Neurol. 2024 Mar 18. pii: S0014-4886(24)00083-9. [Epub ahead of print]376 114757
    Mitochondria-lysosome-extracellular vesicles axis and nanotheranostics in neurodegenerative diseases.
    Liang Kou, Yiming Wang, Jingwen Li, Wenkai Zou, Zongjie Jin, Sijia Yin, Xiaosa Chi, Yadi Sun, Jiawei Wu, Tao Wang, Yun Xia.
      The intricate functional interactions between mitochondria and lysosomes play a pivotal role in maintaining cellular homeostasis and proper cellular functions. This dynamic interplay involves the exchange of molecules and signaling, impacting cellular metabolism, mitophagy, organellar dynamics, and cellular responses to stress. Dysregulation of these processes has been implicated in various neurodegenerative diseases. Additionally, mitochondrial-lysosomal crosstalk regulates the exosome release in neurons and glial cells. Under stress conditions, neurons and glial cells exhibit mitochondrial dysfunction and a fragmented network, which further leads to lysosomal dysfunction, thereby inhibiting autophagic flux and enhancing exosome release. This comprehensive review synthesizes current knowledge on mitochondrial regulation of cell death, organelle dynamics, and vesicle trafficking, emphasizing their significant contributions to neurodegenerative diseases. Furthermore, we explore the emerging field of nanomedicine in the management of neurodegenerative diseases. The review provides readers with an insightful overview of nano strategies that are currently advancing the mitochondrial-lysosome-extracellular vesicle axis as a therapeutic approach for mitigating neurodegenerative diseases.
    Keywords:  Extracellular vesicles axis; Lysosome; Mitochondria; Nanotheranostics; Neurodegenerative diseases
    DOI:  https://doi.org/10.1016/j.expneurol.2024.114757
  13. Shock. 2024 Mar 13.
    Reduced Cx43 Expression Induces Autophagy through Activation of the AMPK-mTOR-ULK1 Signaling Pathway in the Common Bile Duct Ligation Rat Heart.
    Xiaoyu Wang, Pingping Liao, He Dong, Aijie Liu, Qian Wang, Han Yang, Xiaolin Xu, Dongyue Chai, Lin Zhu, Lin Lyu.
      BACKGROUNDS: This study aimed to investigate the relationship between Cx43 expression and autophagy mediated by the AMPK-mTOR-Ulk1 signaling pathway in jaundice heart.METHODS: In this study, a jaundice model was established in common bile duct ligation (CBDL) rats. Cardiac injury was assessed using various methods including myocardial injury indicators, echocardiography, TEM, HE staining, Masson staining, IHC, and IF. We investigated the regulatory relationship between Cx43, autophagy, and the AMPK-mTOR-ULK pathway in vivo by administering autophagy agonists (Rapa), autophagy inhibitors (3-MA), and Cx43 inhibitors (Gap 26). In vitro, we observed the relationship between autophagy and the AMPK-mTOR-ULK1 pathway in cells by exposing them to the AMPK inhibitor Compound C and the AMPK activator AICAR.
    RESULTS: We found that CBDL induced autophagy through the AMPK-mTOR-ULK pathway, leading to the inhibition of myocardial dysfunction. Rapamycin pretreatment with CBDL3d exhibited a protective effect against myocardial injury and promoted autophagy. In contrast, 3-MA had no impact. Pretreatment with rapamycin at CBDL2w enhanced autophagy and aggravated cardiac injury; however, inhibition of autophagy using 3-MA attenuated cardiac injury. Cell viability was enhanced by AMPK inhibitors and inhibited by AMPK agonists. In addition, we observed that increased autophagy led to decreased Cx43 expression, which negatively affected cardiac function.
    CONCLUSIONS: CBDL induces myocardial injury in rats and activates autophagy through the AMPK-mTOR-ULK pathway, resulting in decreased Cx43 protein levels. A moderate increase in early autophagy in CBDL can improve cardiac injury, while late inhibition of autophagy can reduce myocardial injury.
    DOI:  https://doi.org/10.1097/SHK.0000000000002360
  14. Nat Metab. 2024 Mar 19.
    AMPK and insulin control the switch between mitochondrial hitchhiking of Pink1 mRNA and mitophagy in neurons.
      
    DOI:  https://doi.org/10.1038/s42255-024-01006-x
  15. Autophagy. 2024 Mar 22. 1-19
    Foot-and-mouth disease virus VP1 degrades YTHDF2 through autophagy to regulate IRF3 activity for viral replication.
    Huisheng Liu, Qiao Xue, Fan Yang, Weijun Cao, Pengfei Liu, Xiangtao Liu, Zixiang Zhu, Haixue Zheng.
      Many viruses, including foot-and-mouth disease virus (FMDV), can promote the degradation of host proteins through macroautophagy/autophagy, thereby promoting viral replication. However, the regulatory mechanism between autophagy and innate immune responses is not fully understood during FMDV infection. Here, we found that the host GTPBP4/NOG1 (GTP binding protein 4) is a negative regulator of innate immune responses. GTPBP4 deficiency promotes the antiviral innate immune response, resulting in the ability of GTPBP4 to promote FMDV replication. Meanwhile, GTPBP4-deficient mice are more resistant to FMDV infection. To antagonize the host's antiviral immunity, FMDV structural protein VP1 promotes the expression of GTPBP4, and the 209th site of VP1 is responsible for this effect. Mechanically, FMDV VP1 promotes autophagy during virus infection and interacts with and degrades YTHDF2 (YTH N6-methyladenosine RNA binding protein F2) in an AKT-MTOR-dependent autophagy pathway, resulting in an increase in GTPBP4 mRNA and protein levels. Increased GTPBP4 inhibits IRF3 binding to the Ifnb/Ifn-β promoter, suppressing FMDV-induced type I interferon production. In conclusion, our study revealed an underlying mechanism of how VP1 negatively regulates innate immunity through the autophagy pathway, which would contribute to understanding the negative regulation of host innate immune responses and the function of GTPBP4 and YTHDF2 during FMDV infection.Abbreviation: 3-MA:3-methyladenine; ACTB: actin beta; ATG: autophagy related; ChIP:chromatin immunoprecipitation; CQ: chloroquine; DAPI:4',6-diamidino-2-phenylindole; dpi: days post-infection; EV71:enterovirus 71; FMDV: foot-and-mouth disease virus; GTPBP4/NOG1: GTPbinding protein 4; HIF1A: hypoxia inducible factor 1 subunit alpha;hpt:hours post-transfection; IFNB/IFN-β:interferon beta; IRF3: interferon regulatory factor 3; MAP1LC3/LC3:microtubule associated protein 1 light chain 3; MAVS: mitochondriaantiviral signaling protein; MOI: multiplicity of infection; MTOR:mechanistic target of rapamycin kinase; m6A: N(6)-methyladenosine;qPCR:quantitativePCR; SIRT3:sirtuin 3; SQSTM1/p62: sequestosome 1; STING1: stimulator ofinterferon response cGAMP interactor 1; siRNA: small interfering RNA;TBK1: TANK binding kinase 1; TCID50:50% tissue culture infectious doses; ULK1: unc-51 like autophagyactivating kinase 1; UTR: untranslated region; WT: wild type; YTHDF2:YTH N6-methyladenosine RNA binding protein F2.
    Keywords:  Autophagy; FMDV; GTPBP4; IRF3; MTOR; YTHDF2
    DOI:  https://doi.org/10.1080/15548627.2024.2330105
  16. Mol Neurodegener. 2024 Mar 19. 19(1): 26
    A partial Drp1 knockout improves autophagy flux independent of mitochondrial function.
    Rebecca Z Fan, Carolina Sportelli, Yanhao Lai, Said S Salehe, Jennifer R Pinnell, Harry J Brown, Jason R Richardson, Shouqing Luo, Kim Tieu.
      BACKGROUND: Dynamin-related protein 1 (Drp1) plays a critical role in mitochondrial dynamics. Partial inhibition of this protein is protective in experimental models of neurological disorders such as Parkinson's disease and Alzheimer's disease. The protective mechanism has been attributed primarily to improved mitochondrial function. However, the observations that Drp1 inhibition reduces protein aggregation in such neurological disorders suggest the involvement of autophagy. To investigate this potential novel protective mechanism of Drp1 inhibition, a model with impaired autophagy without mitochondrial involvement is needed.METHODS: We characterized the effects of manganese (Mn), which causes parkinsonian-like symptoms in humans, on autophagy and mitochondria by performing dose-response studies in two cell culture models (stable autophagy HeLa reporter cells and N27 rat immortalized dopamine neuronal cells). Mitochondrial function was assessed using the Seahorse Flux Analyzer. Autophagy flux was monitored by quantifying the number of autophagosomes and autolysosomes, as well as the levels of other autophagy proteins. To strengthen the in vitro data, multiple mouse models (autophagy reporter mice and mutant Drp1+/- mice and their wild-type littermates) were orally treated with a low chronic Mn regimen that was previously reported to increase α-synuclein aggregation and transmission via exosomes. RNAseq, laser captured microdissection, immunofluorescence, immunoblotting, stereological cell counting, and behavioural studies were used. RESULTS IN VITRO: data demonstrate that at low non-toxic concentrations, Mn impaired autophagy flux but not mitochondrial function and morphology. In the mouse midbrain, RNAseq data further confirmed autophagy pathways were dysregulated but not mitochondrial related genes. Additionally, Mn selectively impaired autophagy in the nigral dopamine neurons but not the nearby nigral GABA neurons. In cells with a partial Drp1-knockdown and Drp1+/- mice, Mn induced autophagic impairment was significantly prevented. Consistent with these observations, Mn increased the levels of proteinase-K resistant α-synuclein and Drp1-knockdown protected against this pathology.
    CONCLUSIONS: This study demonstrates that improved autophagy flux is a separate mechanism conferred by Drp1 inhibition independent of its role in mitochondrial fission. Given that impaired autophagy and mitochondrial dysfunction are two prominent features of neurodegenerative diseases, the combined protective mechanisms targeting these two pathways conferred by Drp1 inhibition make this protein an attractive therapeutic target.
    Keywords:  Autophagy; Dynamin related protein 1; Manganese; Mitochondrial dynamics; Mitochondrial dysfunction; Parkinson’s disease; Protein aggregation; α-synuclein
    DOI:  https://doi.org/10.1186/s13024-024-00708-w
  17. Methods Mol Biol. 2024 Mar 19.
    Evaluation of Autophagy in Conjunctival Fibroblasts.
    Parvaneh Mehrbod, Paola Brun, Umberto Rosani, Andrea Leonardi, Saeid Ghavami.
      Vernal keratoconjunctivitis (VKC) is a serious eye allergy characterized by poorly understood pathogenic mechanisms and a lack of effective treatments. Autophagy, a process involved in both triggering and suppressing immune and inflammatory responses, plays a role in VKC's pathophysiology. Understanding autophagy's involvement in VKC could lead to new treatment possibilities, such as utilizing specific topical substances to induce or inhibit autophagy and prevent severe complications of this eye condition. In our current protocol, we present a robust methodology established in our laboratory for studying autophagy in primary conjunctival fibroblasts. We assess autophagy through techniques like immunocytochemistry, immunoblotting, and qPCR.
    Keywords:  Autophagy flux; Chloroquine; Vernal keratoconjunctivitis
    DOI:  https://doi.org/10.1007/7651_2024_523
  18. J Biol Chem. 2024 Mar 18. pii: S0021-9258(24)01693-4. [Epub ahead of print] 107198
    The SCF-FBW7β E3 ligase mediates ubiquitination and degradation of the serine/threonine protein kinase PINK1.
    Seo Jeong Jeon, Kwang Chul Chung.
      Understanding the mechanisms that govern the stability of functionally crucial proteins is essential for various cellular processes, development, and overall cell viability. Disturbances in protein homeostasis are linked to the pathogenesis of neurodegenerative diseases (NDDs). PINK1, a protein kinase, plays a significant role in mitochondrial quality control and cellular stress response, and its mutated forms lead to early-onset Parkinson's disease (PD). Despite its importance, the specific mechanisms regulating PINK1 protein stability have remained unclear. This study reveals a cytoplasmic interaction between PINK1 and FBW7β in mammalian cells. FBW7β, a component of the Skp1-Cullin-1-F-box protein (SCF) complex-type ubiquitin ligase, is instrumental in recognizing substrates. Our findings demonstrate that FBW7β regulates PINK1 stability through the SCF complex and the proteasome pathway. It facilitates the K48-linked polyubiquitination of PINK1, marking it for degradation. When FBW7 is absent, PINK1 accumulates, leading to heightened mitophagy triggered by carbonyl cyanide 3-chlorophenylhydrazone treatment. Moreover, exposure to the toxic compound staurosporine accelerates PINK1 degradation via FBW7β, correlating with increased cell death. This study unravels the intricate mechanisms controlling PINK1 protein stability and sheds light on the novel role of FBW7β. These findings deepen our understanding of PINK1-related pathologies and potentially pave the way for therapeutic interventions.
    Keywords:  FBW7; Neurodegenerative diseases; PINK1; Parkinson's disease; Proteasomal degradation; SCF complex; Ubiquitination
    DOI:  https://doi.org/10.1016/j.jbc.2024.107198
  19. Mol Cell. 2024 Mar 14. pii: S1097-2765(24)00172-2. [Epub ahead of print]
    Lysosomal damage sensing and lysophagy initiation by SPG20-ITCH.
    Pinki Gahlot, Bojana Kravic, Giulia Rota, Johannes van den Boom, Sophie Levantovsky, Nina Schulze, Elena Maspero, Simona Polo, Christian Behrends, Hemmo Meyer.
      Cells respond to lysosomal membrane permeabilization by membrane repair or selective macroautophagy of damaged lysosomes, termed lysophagy, but it is not fully understood how this decision is made. Here, we uncover a pathway in human cells that detects lipid bilayer perturbations in the limiting membrane of compromised lysosomes, which fail to be repaired, and then initiates ubiquitin-triggered lysophagy. We find that SPG20 binds the repair factor IST1 on damaged lysosomes and, importantly, integrates that with the detection of damage-associated lipid-packing defects of the lysosomal membrane. Detection occurs via sensory amphipathic helices in SPG20 before rupture of the membrane. If lipid-packing defects are extensive, such as during lipid peroxidation, SPG20 recruits and activates ITCH, which marks the damaged lysosome with lysine-63-linked ubiquitin chains to initiate lysophagy and thus triages the lysosome for destruction. With SPG20 being linked to neurodegeneration, these findings highlight the relevance of a coordinated lysosomal damage response for cellular homeostasis.
    Keywords:  ESCRT; ITCH; Troyer syndrome; lipid sensing; lysophagy; lysosomal membrane permeabilization; lysosomal repair; spartin; spastic paraplegia; ubiquitin
    DOI:  https://doi.org/10.1016/j.molcel.2024.02.029
  20. Mitochondrion. 2024 Mar 19. pii: S1567-7249(24)00032-1. [Epub ahead of print] 101874
    Interplay of mitochondria associated membrane proteins and autophagy: Implications in neurodegeneration.
    Prakash G Kulkarni, Vaibhavi M Mohire, Pranjal P Waghmare, Tanushree Banerjee.
      Since the discovery of membrane contact sites between ER and mitochondria called mitochondria-associated membranes (MAMs), several pieces of evidence identified their role in the regulation of different cellular processes such as Ca2+ signalling, mitochondrial transport, and dynamics, ER stress, inflammation, glucose homeostasis, and autophagy. The integrity of these membranes was found to be essential for the maintenance of these cellular functions. Accumulating pieces of evidence suggest that MAMs serve as a platform for autophagosome formation. However, the alteration within MAMs' structure is associated with the progression of neurodegenerative diseases. Dysregulated autophagy is a hallmark of neurodegeneration. Here, in this review, we highlight the present knowledge on MAMs, their structural composition, and their roles in different cellular functions. We also discuss the association of MAMs proteins with impaired autophagy and their involvement in the progression of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease.
    Keywords:  Alzheimer’s disease (AD); Autophagy; Mitochondrial associated membranes (MAMs); Mitophagy; Parkinson’s disease (PD)
    DOI:  https://doi.org/10.1016/j.mito.2024.101874
  21. Front Pharmacol. 2024 ;15 1355246
    Traditional Chinese medicine and its active substances reduce vascular injury in diabetes via regulating autophagic activity.
    Yankui Gao, Lei Zhang, Fei Zhang, Rong Liu, Lei Liu, Xiaoyan Li, Xiangdong Zhu, Yonglin Liang.
      Due to its high prevalence, poor prognosis, and heavy burden on healthcare costs, diabetic vascular complications have become a significant public health issue. Currently, the molecular and pathophysiological mechanisms underlying diabetes-induced vascular complications remain incompletely understood. Autophagy, a highly conserved process of lysosomal degradation, maintains intracellular homeostasis and energy balance via removing protein aggregates, damaged organelles, and exogenous pathogens. Increasing evidence suggests that dysregulated autophagy may contribute to vascular abnormalities in various types of blood vessels, including both microvessels and large vessels, under diabetic conditions. Traditional Chinese medicine (TCM) possesses the characteristics of "multiple components, multiple targets and multiple pathways," and its safety has been demonstrated, particularly with minimal toxicity in liver and kidney. Thus, TCM has gained increasing attention from researchers. Moreover, recent studies have indicated that Chinese herbal medicine and its active compounds can improve vascular damage in diabetes by regulating autophagy. Based on this background, this review summarizes the classification, occurrence process, and related molecular mechanisms of autophagy, with a focus on discussing the role of autophagy in diabetic vascular damage and the protective effects of TCM and its active compounds through the regulation of autophagy in diabetes. Moreover, we systematically elucidate the autophagic mechanisms by which TCM formulations, individual herbal extracts, and active compounds regulate diabetic vascular damage, thereby providing new candidate drugs for clinical treatment of vascular complications in diabetes. Therefore, further exploration of TCM and its active compounds with autophagy-regulating effects holds significant research value for achieving targeted therapeutic approaches for diabetic vascular complications.
    Keywords:  TCM formulations; active compounds; autophagy; diabetic vascular complications; herbal extracts
    DOI:  https://doi.org/10.3389/fphar.2024.1355246
  22. Nat Metab. 2024 Mar 19.
    Insulin signalling regulates Pink1 mRNA localization via modulation of AMPK activity to support PINK1 function in neurons.
    J Tabitha Hees, Simone Wanderoy, Jana Lindner, Marlena Helms, Hariharan Murali Mahadevan, Angelika B Harbauer.
      Mitochondrial quality control failure is frequently observed in neurodegenerative diseases. The detection of damaged mitochondria by stabilization of PTEN-induced kinase 1 (PINK1) requires transport of Pink1 messenger RNA (mRNA) by tethering it to the mitochondrial surface. Here, we report that inhibition of AMP-activated protein kinase (AMPK) by activation of the insulin signalling cascade prevents Pink1 mRNA binding to mitochondria. Mechanistically, AMPK phosphorylates the RNA anchor complex subunit SYNJ2BP within its PDZ domain, a phosphorylation site that is necessary for its interaction with the RNA-binding protein SYNJ2. Notably, loss of mitochondrial Pink1 mRNA association upon insulin addition is required for PINK1 protein activation and its function as a ubiquitin kinase in the mitophagy pathway, thus placing PINK1 function under metabolic control. Induction of insulin resistance in vitro by the key genetic Alzheimer risk factor apolipoprotein E4 retains Pink1 mRNA at the mitochondria and prevents proper PINK1 activity, especially in neurites. Our results thus identify a metabolic switch controlling Pink1 mRNA localization and PINK1 activity via insulin and AMPK signalling in neurons and propose a mechanistic connection between insulin resistance and mitochondrial dysfunction.
    DOI:  https://doi.org/10.1038/s42255-024-01007-w
  23. J Agric Food Chem. 2024 Mar 19.
    Ferritinophagy Is Critical for Deoxynivalenol-Induced Liver Injury in Mice.
    Junze Jiang, Yongbao Ruan, Xiaohui Liu, Jun Ma, Hao Chen.
      Background: Deoxynivalenol (DON) contamination, pervasive throughout all stages of food production and processing, presents a significant threat to human health. The degradation of ferritin mediated by nuclear receptor coactivator 4 (NCOA4), termed ferritinophagy, plays a crucial role in maintaining iron homeostasis and regulating ferroptosis. Aim: This study aims to elucidate the role of ferritinophagy and ferroptosis in DON-induced liver injury. Methods: Male mice and AML12 cells were subjected to varying doses of DON, serving as in vivo and in vitro models, respectively. Protein expression was assessed by using immunofluorescence and western blot techniques. Co-immunoprecipitation was employed to investigate the protein-protein interactions. Results: Our findings demonstrate that DON triggers hepatocyte ferroptosis in a ferritinophagy-dependent manner. Specifically, DON impedes the activation of the mammalian target of rapamycin complex 1 (mTORC1) by inhibiting RAC1's binding to mTOR, thereby ultimately inducing autophagy. Concurrently, DON amplifies NCOA4's affinity for ferritin by facilitating NCOA4 phosphorylation through the ataxia-telangiectasia mutated kinase (ATM), thus promoting the autophagy-dependent degradation of ferritin. Both autophagy inhibition and NCOA4 expression suppression ameliorate DON-induced ferroptosis. Conclusion: Our study concludes that DON facilitates NCOA4-mediated ferritinophagy via the ATM-NCOA4 pathway, subsequently inducing ferroptosis in the liver.
    Keywords:  deoxynivalenol; ferritinophagy; ferroptosis
    DOI:  https://doi.org/10.1021/acs.jafc.4c00556
  24. Cell Death Discov. 2024 Mar 21. 10(1): 149
    miR-218-5p and doxorubicin combination enhances anticancer activity in breast cancer cells through Parkin-dependent mitophagy inhibition.
    Francesco Davide Naso, Krenare Bruqi, Valeria Manzini, Valerio Chiurchiù, Mara D'Onofrio, Ivan Arisi, Flavie Strappazzon.
      Breast Cancer (BC) is one of the most common tumours, and is known for its ability to develop resistance to chemotherapeutic treatments. Autophagy has been linked to chemotherapeutic response in several types of cancer, highlighting its contribution to this process. However, the role of mitophagy, a selective form of autophagy responsible for damaged mitochondria degradation, in the response to therapies in BC is still unclear. In order to address this point, we analysed the role of mitophagy in the treatment of the most common anticancer drug, doxorubicin (DXR), in different models of BC, such as a luminal A subtype-BC cell line MCF7 cells, cultured in 2-Dimension (2D) or in 3-Dimension (3D), and the triple negative BC (TNBC) cell line MDA-MB-231. Through a microarray analysis, we identified a relationship between mitophagy gene expressions related to the canonical PINK1/Parkin-mediated pathway and DXR treatment in BC cells. Afterwards, we demonstrated that the PINK1/Parkin-dependent mitophagy is indeed induced following DXR treatment and that exogenous expression of a small non-coding RNA, the miRNA-218-5p, known to target mRNA of Parkin, was sufficient to inhibit the DXR-mediated mitophagy in MCF7 and in MDA-MB-231 cells, thereby increasing their sensitivity to DXR. Considering the current challenges involved in BC refractory to treatment, our work could provide a promising approach to prevent tumour resistance and recurrence, potentially leading to the development of an innovative approach to combine mitophagy inhibition and chemotherapy.
    DOI:  https://doi.org/10.1038/s41420-024-01914-7
  25. Autophagy. 2024 Mar 21.
    The activation mechanism of Atg15, a vacuolar phospholipase required for the disintegration of organelle membranes.
    Yasunori Watanabe, Kuninori Suzuki.
      The disintegration of cytoplasm-to-vacuole targeting (Cvt) bodies and autophagic bodies in vacuoles is essential to the Cvt pathway and macroautophagy in yeast. Atg15 is a vacuolar lipase required for the degradation of both Cvt and autophagic bodies. However, the molecular mechanism of their degradation by Atg15 remains poorly understood. In a recent study, we showed that recombinant Chaetomium thermophilum Atg15 (CtAtg15) possesses phospholipase activity, and that this activity is significantly elevated by proteolytic cleavage at a site away from the active center. The proteolytic cleavage of CtAtg15 causes a conformational change around the active center, resulting in the active open state. Interestingly, activated CtAtg15 can degrade not only Cvt and autophagic bodies but also organelle membranes. On the basis of these results, we propose an activation mechanism by which Atg15, as an "organellase," functions only in vacuoles.
    Keywords:  Atg15; autophagic body; organelle membrane; phospholipase; vacuolar proteases; yeast
    DOI:  https://doi.org/10.1080/15548627.2024.2333165
  26. iScience. 2024 Apr 19. 27(4): 109354
    Cell non-autonomous control of autophagy and metabolism by glial cells.
    Melissa G Metcalf, Samira Monshietehadi, Arushi Sahay, Jenni Durieux, Ashley E Frakes, Martina Velichkovska, Cesar Mena, Amelia Farinas, Melissa Sanchez, Andrew Dillin.
      Glia are the protectors of the nervous system, providing neurons with support and protection from cytotoxic insults. We previously discovered that four astrocyte-like glia can regulate organismal proteostasis and longevity in C. elegans. Expression of the UPRER transcription factor, XBP-1s, in these glia increases stress resistance, and longevity, and activates the UPRER in intestinal cells via neuropeptides. Autophagy, a key regulator of metabolism and aging, has been described as a cell autonomous process. Surprisingly, we find that glial XBP-1s enhances proteostasis and longevity by cell non-autonomously reprogramming organismal lipid metabolism and activating autophagy. Glial XBP-1s regulates the activation of another transcription factor, HLH-30/TFEB, in the intestine. HLH-30 activates intestinal autophagy, increases intestinal lipid catabolism, and upregulates a robust transcriptional program. Our study reveals a novel role for glia in regulating peripheral lipid metabolism, autophagy, and organellar health through peripheral activation of HLH-30 and autophagy.
    Keywords:  Biological sciences; Cell biology; Functional aspects of cell biology; Neuroscience
    DOI:  https://doi.org/10.1016/j.isci.2024.109354
  27. Plant Physiol Biochem. 2024 Mar 07. pii: S0981-9428(24)00139-6. [Epub ahead of print]208 108471
    Arabidopsis BECLIN1-induced autophagy mediates reprogramming in tapetal programmed cell death by altering the gross cellular homeostasis.
    Surendra Pratap Singh, Rishi Kumar Verma, Ridhi Goel, Verandra Kumar, Ram Rakshpal Singh, Samir V Sawant.
      In flowering plants, the tapetum degeneration in post-meiotic anther occurs through developmental programmed cell death (dPCD), which is one of the most critical and sensitive steps for the proper development of male gametophytes and fertility. Yet the pathways of dPCD, its regulation, and its interaction with autophagy remain elusive. Here, we report that high-level expression of Arabidopsis autophagy-related gene BECLIN1 (BECN1 or AtATG6) in the tobacco tapetum prior to their dPCD resulted in developmental defects. BECN1 induces severe autophagy and multiple cytoplasm-to-vacuole pathways, which alters tapetal cell reactive oxygen species (ROS)-homeostasis that represses the tapetal dPCD. The transcriptome analysis reveals that BECN1- expression caused major changes in the pathway, resulting in altered cellular homeostasis in the tapetal cell. Moreover, BECN1-mediated autophagy reprograms the execution of tapetal PCD by altering the expression of the key developmental PCD marker genes: SCPL48, CEP1, DMP4, BFN1, MC9, EXI1, and Bcl-2 member BAG5, and BAG6. This study demonstrates that BECN1-mediated autophagy is inhibitory to the dPCD of the tapetum, but the severity of autophagy leads to autophagic death in the later stages. The delayed and altered mode of tapetal degeneration resulted in male sterility.
    Keywords:  Anther tapetum; Autophagy; BECLIN1; Reactive oxygen species (ROS); dPCD
    DOI:  https://doi.org/10.1016/j.plaphy.2024.108471
  28. Autophagy. 2024 Mar 21. 1-12
    Emerging dimensions of autophagy in melanoma.
    Christian Pangilinan, Daniel J Klionsky, Chengyu Liang.
      Macroautophagy/autophagy has previously been regarded as simply a way for cells to deal with nutrient emergency. But explosive work in the last 15 years has given increasingly new knowledge to our understanding of this process. Many of the functions of autophagy that are unveiled from recent studies, however, cannot be reconciled with this conventional view of cell survival but, instead, point to autophagy being integrally involved at a deeper level of cell biology, playing a critical role in maintaining homeostasis and promoting an integrated stress/immune response. The new appreciation of the role of autophagy in the evolutionary trajectory of cancer and cancer interaction with the immune system provides a mechanistic framework for understanding the clinical benefits of autophagy-based therapies. Here, we examine current knowledge of the mechanisms and functions of autophagy in highly plastic and aggressive melanoma as a model disease of human malignancy, while highlighting emerging dimensions indicating that autophagy is at play beyond its classical face.Abbreviation: AMBRA1: autophagy and beclin 1 regulator 1; AMPK: AMP-activated protein kinase; ATF4: activating transcription factor 4; ATG: autophagy related; BRAF: B-Raf proto-oncogene, serine/threonine kinase; CAFs: cancer-associated fibroblasts; CCL5: C-C motif chemokine ligand 5; CQ: chloroquine; CRISPR: clustered regularly interspaced short palindromic repeats; CTLA4: cytotoxic T-lymphocyte associated protein 4; CTL: cytotoxic T lymphocyte; DAMPs: danger/damage-associated molecular patterns; EGFR: epidermal growth factor receptor; EIF2A/eIF2α: eukaryotic translation initiation factor 2A; EIF2AK3/PERK: eukaryotic translation initiation factor 2 alpha kinase 3; ER: endoplasmic reticulum; FITM2: fat storage inducing transmembrane protein 2; HCQ: hydroxychloroquine; ICB: immune checkpoint blockade; ICD: immunogenic cell death; LDH: lactate dehydrogenase; MAPK: mitogen-activated protein kinase; MTORC1: mechanistic target of rapamycin kinase complex 1; NDP52: nuclear dot protein 52; NFKB/NF-κ B: nuclear factor kappa B; NBR1: the neighbor of BRCA1; NK: natural killer; NRF1: nuclear respiratory factor 1; NSCLC: non-small-cell lung cancer; OPTN: optineurin; PDAC: pancreatic ductal adenocarcinoma; PDCD1/PD-1: programmed cell death 1; PPT1: palmitoyl-protein thioesterase 1; PTEN: phosphatase and tensin homolog; PTK2/FAK1: protein tyrosine kinase 2; RAS: rat sarcoma; SQSTM1/p62: sequestosome 1; STK11/LKB1: serine/threonine kinase 11; TAX1BP1: Tax1 binding protein 1; TFEB: transcription factor EB; TGFB/TGF-β: transforming growth factor beta; TMB: tumor mutational burden; TME: tumor microenvironment; TSC1: TSC complex subunit 1; TSC2: TSC complex subunit 2; ULK1: unc-51 like autophagy activating kinase 1; UVRAG: UV radiation resistance associated.
    Keywords:  Autophagy; homeostasis; immunotherapy; melanoma; targeted therapy; tumor microenvironment
    DOI:  https://doi.org/10.1080/15548627.2024.2330261
  29. mBio. 2024 Mar 19. e0334423
    MoMkk1 and MoAtg1 dichotomously regulating autophagy and pathogenicity through MoAtg9 phosphorylation in Magnaporthe oryzae.
    Yun Kong, Pusheng Guo, Jiayun Xu, Jiaxu Li, Miao Wu, Ziqi Zhang, Yifan Wang, Xinyu Liu, Leiyun Yang, Muxing Liu, Haifeng Zhang, Ping Wang, Zhengguang Zhang.
      Autophagy is a central biodegradation pathway critical in eliminating intracellular cargo to maintain cellular homeostasis and improve stress resistance. At the same time, the key component of the mitogen-activated protein kinase cascade regulating cell wall integrity signaling MoMkk1 has an essential role in the autophagy of the rice blast fungus Magnaporthe oryzae. Still, the mechanism of how MoMkk1 regulates autophagy is unclear. Interestingly, we found that MoMkk1 regulates the autophagy protein MoAtg9 through phosphorylation. MoAtg9 is a transmembrane protein subjected to phosphorylation by autophagy-related protein kinase MoAtg1. Here, we provide evidence demonstrating that MoMkk1-dependent MoAtg9 phosphorylation is required for phospholipid translocation during isolation membrane stages of autophagosome formation, an autophagic process essential for the development and pathogenicity of the fungus. In contrast, MoAtg1-dependent phosphorylation of MoAtg9 negatively regulates this process, also impacting growth and pathogenicity. Our studies are the first to demonstrate that MoAtg9 is subject to MoMkk1 regulation through protein phosphorylation and that MoMkk1 and MoAtg1 dichotomously regulate autophagy to underlie the growth and pathogenicity of M. oryzae.IMPORTANCEMagnaporthe oryzae utilizes multiple signaling pathways to promote colonization of host plants. MoMkk1, a cell wall integrity signaling kinase, plays an essential role in autophagy governed by a highly conserved autophagy kinase MoAtg1-mediated pathway. How MoMkk1 regulates autophagy in coordination with MoAtg1 remains elusive. Here, we provide evidence that MoMkk1 phosphorylates MoAtg9 to positively regulate phospholipid translocation during the isolation membrane or smaller membrane structures stage of autophagosome formation. This is in contrast to the negative regulation of MoAtg9 by MoAtg1 for the same process. Intriguingly, MoMkk1-mediated MoAtg9 phosphorylation enhances the fungal infection of rice, whereas MoAtg1-dependant MoAtg9 phosphorylation significantly attenuates it. Taken together, we revealed a novel mechanism of autophagy and virulence regulation by demonstrating the dichotomous functions of MoMkk1 and MoAtg1 in the regulation of fungal autophagy and pathogenicity.
    Keywords:  Magnaporthe oryzae; autophagy; cell wall integrity; phospholipid; protein phosphorylation
    DOI:  https://doi.org/10.1128/mbio.03344-23
  30. Mol Metab. 2024 Mar 14. pii: S2212-8778(24)00047-4. [Epub ahead of print] 101916
    Scd1 and monounsaturated lipids are required for autophagy and survival of adipocytes.
    Hiroyuki Mori, Sydney K Peterson, Rachel C Simmermon, Katherine A Overmyer, Akira Nishii, Emma Paulsson, Ziru Li, Annie Jen, Romina M Uranga, Jessica N Maung, Warren T Yacawych, Kenneth T Lewis, Rebecca L Schill, Taryn Hetrick, Ryo Seino, Ken Inoki, Joshua J Coon, Ormond A MacDougald.
      Exposure of adipocytes to 'cool' temperatures often found in the periphery of the body induces expression of Stearoyl-CoA Desaturase-1 (Scd1), an enzyme that converts saturated fatty acids to monounsaturated fatty acids. In this study, we employed Scd1 knockout cells and mouse models, along with pharmacological Scd1 inhibition, to investigate further the roles of Scd1 in adipocytes. Our study reveals that production of monounsaturated lipids by Scd1 is necessary for fusion of autophagosomes to lysosomes and that with a Scd1-deficiency, autophagosomes accumulate. In addition, Scd1-deficiency impairs lysosomal and autolysosomal acidification resulting in vacuole accumulation and eventual cell death. Blocking autophagosome formation or supplementation with monounsaturated fatty acids maintains vitality of Scd1-deficient adipocytes. Taken together, our results demonstrate that in vitro inhibition of Scd1 in adipocytes leads to autophagy-dependent cell death, and in vivo depletion leads to loss of bone marrow adipocytes.
    Keywords:  ADCD; Autophagy-dependent cell death; BMAT; BMAds; Bone marrow adipocytes; Bone marrow adipose tissue; MUFA; Monounsaturated fatty acid; Scd1; Stearoyl CoA Desaturase 1
    DOI:  https://doi.org/10.1016/j.molmet.2024.101916
  31. PLoS One. 2024 ;19(3): e0300337
    mTORC1 is required for differentiation of germline stem cells in the Drosophila melanogaster testis.
    Marie Clémot, Cecilia D'Alterio, Alexa C Kwang, D Leanne Jones.
      Metabolism participates in the control of stem cell function and subsequent maintenance of tissue homeostasis. How this is achieved in the context of adult stem cell niches in coordination with other local and intrinsic signaling cues is not completely understood. The Target of Rapamycin (TOR) pathway is a master regulator of metabolism and plays essential roles in stem cell maintenance and differentiation. In the Drosophila male germline, mTORC1 is active in germline stem cells (GSCs) and early germ cells. Targeted RNAi-mediated downregulation of mTor in early germ cells causes a block and/or a delay in differentiation, resulting in an accumulation of germ cells with GSC-like features. These early germ cells also contain unusually large and dysfunctional autolysosomes. In addition, downregulation of mTor in adult male GSCs and early germ cells causes non-autonomous activation of mTORC1 in neighboring cyst cells, which correlates with a disruption in the coordination of germline and somatic differentiation. Our study identifies a previously uncharacterized role of the TOR pathway in regulating male germline differentiation.
    DOI:  https://doi.org/10.1371/journal.pone.0300337
  32. Pathol Oncol Res. 2024 ;30 1611643
    mTOR hyperactivity and RICTOR amplification as targets for personalized treatments in malignancies.
    Dániel Sztankovics, Dorottya Moldvai, Gábor Petővári, Titanilla Dankó, Fatime Szalai, Risa Miyaura, Viktória Varga, Noémi Nagy, Gergő Papp, Judit Pápay, Ildikó Krencz, Anna Sebestyén.
      The increasing knowledge of molecular alterations in malignancies, including mutations and regulatory failures in the mTOR (mechanistic target of rapamycin) signaling pathway, highlights the importance of mTOR hyperactivity as a validated target in common and rare malignancies. This review summarises recent findings on the characterization and prognostic role of mTOR kinase complexes (mTORC1 and mTORC2) activity regarding differences in their function, structure, regulatory mechanisms, and inhibitor sensitivity. We have recently identified new tumor types with RICTOR (rapamycin-insensitive companion of mTOR) amplification and associated mTORC2 hyperactivity as useful potential targets for developing targeted therapies in lung cancer and other newly described malignancies. The activity of mTOR complexes is recommended to be assessed and considered in cancers before mTOR inhibitor therapy, as current first-generation mTOR inhibitors (rapamycin and analogs) can be ineffective in the presence of mTORC2 hyperactivity. We have introduced and proposed a marker panel to determine tissue characteristics of mTOR activity in biopsy specimens, patient materials, and cell lines. Ongoing phase trials of new inhibitors and combination therapies are promising in advanced-stage patients selected by genetic alterations, molecular markers, and/or protein expression changes in the mTOR signaling pathway. Hopefully, the summarized results, our findings, and the suggested characterization of mTOR activity will support therapeutic decisions.
    Keywords:  RICTOR amplification; Rictor overexpression; mTOR; mTORC2 hyperactivity; malignancies
    DOI:  https://doi.org/10.3389/pore.2024.1611643
  33. Hypertension. 2024 Mar 18.
    Role of Raptor Gene Variants in Hypertension: Influence on Blood Pressure Independent of Salt Intake in White Population.
    Hayat Aljaibeji, Mahyar Heydarpour, Ana Maria Stanton, Jonathan S Williams, Luminita H Pojoga, Jose R Romero, Gordon H Williams.
      BACKGROUND: The mTOR (mechanistic target of rapamycin) is an essential regulator of fundamental biological processes. mTOR forms 2 distinct complexes, mTORC1 (mTOR complex 1) when it binds with RAPTOR (Regulatory-associated Protein of mTOR) and mTORC2 (mTOR complex 2) when it associates with RICTOR (Rapamycin-insesitive companion of mTOR). Due to the previous link between the mTOR pathway, aldosterone, and blood pressure (BP), we anticipated that variants in the mTOR complex might be associated with salt-sensitive BP.METHODS: BP and other parameters were assessed after a one-week liberal Na+ (200 mmol/d) and a one-week restricted Na+ (10 mmol/d) diet in 608 White subjects from the Hypertensive Pathotype cohort, single-nucleotide variants in MTOR, RPTOR, and RICTOR genes were obtained for candidate genes analyses.
    RESULTS: The analysis revealed a significant association between a single nucleotide variants within the RPTOR gene and BP. Individuals carrying the RPTOR rs9901846 homozygous risk allele (AA) and heterozygous risk allele (GA) exhibited a 5 mm Hg increase in systolic BP on a liberal diet compared with nonrisk allele individuals (GG), but only in women. This single nucleotide variants effect was more pronounced on the restricted diet and present in both sexes, with AA carriers having a 9 mm Hg increase and GA carriers having a 5 mm Hg increase in systolic BP compared with GG. Interestingly, there were no significant associations between MTOR or RICTOR gene variants and BP.
    CONCLUSIONS: The RPTOR gene variation is associated with elevated BP in White participants, regardless of salt intake, specifically in females.
    Keywords:  aldosterone; blood pressure; hypertension; mTOR, rictor; nucleotide; raptor
    DOI:  https://doi.org/10.1161/HYPERTENSIONAHA.123.22273
  34. Cell Biochem Funct. 2024 Mar;42(2): e3971
    The interaction between lncRNAs and transcription factors regulating autophagy in human cancers: A comprehensive and therapeutical survey.
    Saade Abdalkareem Jasim, Yasir Qasim Almajidi, Reyadh R Al-Rashidi, Ahmed Hjazi, Irfan Ahmad, Ahmed Hussien Radie Alawadi, Enas R Alwaily, Hashem O Alsaab, Ali Haslany, Mohamood Hameed.
      Autophagy, as a highly conserved cellular process, participates in cellular homeostasis by degradation and recycling of damaged organelles and proteins. Besides, autophagy has been evidenced to play a dual role through cancer initiation and progression. In the early stage, it may have a tumor-suppressive function through inducing apoptosis and removing damaged cells and organelles. However, late stages promote tumor progression by maintaining stemness features and induction of chemoresistance. Therefore, identifying and targeting molecular mechanisms involved in autophagy is a potential therapeutic strategy for human cancers. Multiple transcription factors (TFs) are involved in the regulation of autophagy by modulating the expression of autophagy-related genes (ATGs). In addition, a wide array of long noncoding RNAs (lncRNAs), a group of regulatory ncRNAs, have been evidenced to regulate the function of these autophagy-related TFs through tumorigenesis. Subsequently, the lncRNAs/TFs/ATGs axis shows great potential as a therapeutic target for human cancers. Therefore, this review aimed to summarize new findings about the role of lncRNAs in regulating autophagy-related TFs with therapeutic perspectives.
    Keywords:  autophagy; cancer; lncRNA; transcription factor
    DOI:  https://doi.org/10.1002/cbf.3971
  35. J Vasc Res. 2024 Mar 19. 1-12
    Autophagy Induced by Low Shear Stress Leads to Endothelial Glycocalyx Disruption.
    Lina Lin, Wei Gao, Linya Feng, Chundong Wang, Ruiqi Yang, Weijian Wang, Qiaolin Wu.
      INTRODUCTION: Previous studies have confirmed that low shear stress (LSS) induces glycocalyx disruption, leading to endothelial dysfunction. However, the role of autophagy in LSS-induced glycocalyx disruption and relevant mechanism are not clear. In this study, we hypothesized that LSS may promote autophagy, disrupting the endothelium glycocalyx.METHODS: Human umbilical vein endothelial cells were subjected to physiological shear stress and LSS treatments, followed by the application of autophagy inducers and inhibitors. Additionally, cells were treated with specific matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) inhibitor. The expression of autophagic markers, glycocalyx, MMP-2, and MMP-9 was measured.
    RESULTS: LSS impacted the expression of endothelium autophagy markers, increasing the expression of LC3II.LC3I-1 and Beclin-1, and decreasing the levels of p62, accompanied by glycocalyx disturbance. Moreover, LSS upregulated the expression of MMP-2 and MMP-9 and downregulated the levels of syndecan-1 and heparan sulfate (HS). Additionally, expression of MMP-2 and MMP-9 was increased by an autophagy promoter but was decreased by autophagy inhibitor treatment under LSS. Autophagy and MMP-2 and MMP-9 further caused glycocalyx disruption.
    CONCLUSION: LSS promotes autophagy, leading to glycocalyx disruption. Autophagy increases the expression of MMP-2 and MMP-9, which are correlated with the glycocalyx destruction induced by LSS.
    Keywords:  Autophagy; Glycocalyx; Low shear stress; MMP-2 and MMP-9
    DOI:  https://doi.org/10.1159/000537772
  36. bioRxiv. 2024 Mar 07. pii: 2024.03.06.583589. [Epub ahead of print]
    Up-regulation of cholesterol synthesis by lysosomal defects requires a functional mitochondrial respiratory chain.
    Francesco Agostini, Leonardo Pereyra, Justin Dale, King Faisal Yambire, Silvia Maglioni, Alfonso Schiavi, Natascia Ventura, Ira Milosevic, Nuno Raimundo.
      Mitochondria and lysosomes are two organelles that carry out both signaling and metabolic roles in the cells. Recent evidence has shown that mitochondria and lysosomes are dependent on one another, as primary defects in one cause secondary defects in the other. Nevertheless, the signaling consequences of primary mitochondrial malfunction and of primary lysosomal defects are not similar, despite in both cases there are impairments of mitochondria and of lysosomes. Here, we used RNA sequencing to obtain transcriptomes from cells with primary mitochondrial or lysosomal defects, to identify what are the global cellular consequences that are associated with malfunction of mitochondria or lysosomes. We used these data to determine what are the pathways that are affected by defects in both organelles, which revealed a prominent role for the cholesterol synthesis pathway. This pathway is transcriptionally up-regulated in cellular and mouse models of lysosomal defects and is transcriptionally down-regulated in cellular and mouse models of mitochondrial defects. We identified a role for post-transcriptional regulation of the transcription factor SREBF1, a master regulator of cholesterol and lipid biosynthesis, in models of mitochondrial respiratory chain deficiency. Furthermore, the retention of Ca 2+ in the lysosomes of cells with mitochondrial respiratory chain defects contributes to the differential regulation of the cholesterol synthesis pathway in the mitochondrial and lysosomal defects tested. Finally, we verified in vivo , using models of mitochondria-associated diseases in C. elegans , that normalization of lysosomal Ca 2+ levels results in partial rescue of the developmental arrest induced by the respiratory chain deficiency.
    DOI:  https://doi.org/10.1101/2024.03.06.583589
  37. Nat Commun. 2024 Mar 15. 15(1): 2255
    Autophagy regulates the maturation of hematopoietic precursors in the embryo.
    Yumin Liu, Linjuan Shi, Yifan Chen, Sifan Luo, Yuehang Chen, Hongtian Chen, Wenlang Lan, Xun Lu, Zhan Cao, Zehua Ye, Jinping Li, Bo Yu, Elaine Dzierzak, Zhuan Li.
      An understanding of the mechanisms regulating embryonic hematopoietic stem cell (HSC) development would facilitate their regeneration. The aorta-gonad-mesonephros region is the site for HSC production from hemogenic endothelial cells (HEC). While several distinct regulators are involved in this process, it is not yet known whether macroautophagy (autophagy) plays a role in hematopoiesis in the pre-liver stage. Here, we show that different states of autophagy exist in hematopoietic precursors and correlate with hematopoietic potential based on the LC3-RFP-EGFP mouse model. Deficiency of autophagy-related gene 5 (Atg5) specifically in endothelial cells disrupts endothelial to hematopoietic transition (EHT), by blocking the autophagic process. Using combined approaches, including single-cell RNA-sequencing (scRNA-seq), we have confirmed that Atg5 deletion interrupts developmental temporal order of EHT to further affect the pre-HSC I maturation, and that autophagy influences hemogenic potential of HEC and the formation of pre-HSC I likely via the nucleolin pathway. These findings demonstrate a role for autophagy in the formation/maturation of hematopoietic precursors.
    DOI:  https://doi.org/10.1038/s41467-024-46453-y
  38. Nat Commun. 2024 Mar 18. 15(1): 1878
    Hepatic nutrient and hormone signaling to mTORC1 instructs the postnatal metabolic zonation of the liver.
    Ana Belén Plata-Gómez, Lucía de Prado-Rivas, Alba Sanz, Nerea Deleyto-Seldas, Fernando García, Celia de la Calle Arregui, Camila Silva, Eduardo Caleiras, Osvaldo Graña-Castro, Elena Piñeiro-Yáñez, Joseph Krebs, Luis Leiva-Vega, Javier Muñoz, Ajay Jain, Guadalupe Sabio, Alejo Efeyan.
      The metabolic functions of the liver are spatially organized in a phenomenon called zonation, linked to the differential exposure of portal and central hepatocytes to nutrient-rich blood. The mTORC1 signaling pathway controls cellular metabolism in response to nutrients and insulin fluctuations. Here we show that simultaneous genetic activation of nutrient and hormone signaling to mTORC1 in hepatocytes results in impaired establishment of postnatal metabolic and zonal identity of hepatocytes. Mutant hepatocytes fail to upregulate postnatally the expression of Frizzled receptors 1 and 8, and show reduced Wnt/β-catenin activation. This defect, alongside diminished paracrine Wnt2 ligand expression by endothelial cells, underlies impaired postnatal maturation. Impaired zonation is recapitulated in a model of constant supply of nutrients by parenteral nutrition to piglets. Our work shows the role of hepatocyte sensing of fluctuations in nutrients and hormones for triggering a latent metabolic zonation program.
    DOI:  https://doi.org/10.1038/s41467-024-46032-1
  39. Autophagy. 2024 Mar 18.
    Streptococcus pneumoniae extracellular vesicles aggravate alveolar epithelial barrier disruption via autophagic degradation of OCLN (occludin).
    Luqing Cui, Ruicheng Yang, Dong Huo, Liang Li, Xinyi Qu, Jundan Wang, Xinyi Wang, Hulin Liu, Huanchun Chen, Xiangru Wang.
      Streptococcus pneumoniae (S. pneumoniae) represents a major human bacterial pathogen leading to high morbidity and mortality in children and the elderly. Recent research emphasizes the role of extracellular vesicles (EVs) in bacterial pathogenicity. However, the contribution of S. pneumoniae EVs (pEVs) to host-microbe interactions has remained unclear. Here, we observed that S. pneumoniae infections in mice led to severe lung injuries and alveolar epithelial barrier (AEB) dysfunction. Infections of S. pneumoniae reduced the protein expression of tight junction protein OCLN (occludin) and activated macroautophagy/autophagy in lung tissues of mice and A549 cells. Mechanically, S. pneumoniae induced autophagosomal degradation of OCLN leading to AEB impairment in the A549 monolayer. S. pneumoniae released the pEVs that could be internalized by alveolar epithelial cells. Through proteomics, we profiled the cargo proteins inside pEVs and found that these pEVs contained many virulence factors, among which we identified a eukaryotic-like serine-threonine kinase protein StkP. The internalized StkP could induce the phosphorylation of BECN1 (beclin 1) at Ser93 and Ser96 sites, initiating autophagy and resulting in autophagy-dependent OCLN degradation and AEB dysfunction. Finally, the deletion of stkP in S. pneumoniae completely protected infected mice from death, significantly alleviated OCLN degradation in vivo, and largely abolished the AEB disruption caused by pEVs in vitro. Overall, our results suggested that pEVs played a crucial role in the spread of S. pneumoniae virulence factors. The cargo protein StkP in pEVs could communicate with host target proteins and even hijack the BECN1 autophagy initiation pathway, contributing to AEB disruption and bacterial pathogenicity.
    Keywords:  Alveolar epithelial barrier; Ocln/Occludin; StkP; autophagy; pevs; s. pneumoniae
    DOI:  https://doi.org/10.1080/15548627.2024.2330043
  40. Inflammation. 2024 Mar 19.
    AMPK/MTOR/TP53 Signaling Pathway Regulation by Calcitonin Gene-Related Peptide Reduces Oxygen-Induced Lung Damage in Neonatal Rats through Autophagy Promotion.
    Shaohua Wang, Zhengzhuang Zou, Zanmei Tang, Jian Deng.
      Our previous studies indicated that calcitonin gene-related peptide (CGRP) alleviates hyperoxia-induced lung injury and suggested the possible involvement of autophagy in this process. Herein, we aimed to further explore the potential involvement of tumor protein p53 (TP53) and autophagy in the mode of action of CGRP against hyperoxia-induced lung injury in vitro and in vivo. The study conducted tests on type II alveolar epithelial cells (AECII) and rats that were subjected to hyperoxia treatment or combined treatment of hyperoxia with CGRP, CGRP inhibitor, rapamycin (an autophagy agonist), 3-methyladenine (3-MA, an autophagy inhibitor), TP53 silencing/inhibitor (pifithrin-α), or expression vector/activator (PRIMA-1 (2,2-bis(hydroxymethyl)-3-quinuclidinone)) and their corresponding controls. We found that oxidative stress, apoptosis, and autophagy were all increased by hyperoxia treatment in vitro. However, treating AECII cells with CGRP reversed hyperoxia-induced oxidative stress and apoptosis but further promoted autophagy. In addition, the combined treatment with rapamycin or TP53 silencing with CGRP promoted the effect of CGRP, while contrary results were obtained with combined therapy with 3-MA or TP53 overexpression. In vivo, the number of hyperoxia-induced autophagosomes was promoted in the lung tissue of neonatal rats. Furthermore, hyperoxia increased the expression levels of AMP-activated protein kinase (AMPK) alpha 1 (also known as protein kinase AMP-activated catalytic subunit alpha 1 (PRKAA1)) but inhibited TP53 and mechanistic target of rapamycin (MTOR); these expression trends were regulated by CGRP treatment. In conclusion, we showed that CGRP can attenuate hyperoxia-induced lung injury in neonatal rats by enhancing autophagy and regulating the TP53/AMPK/MTOR crosstalk axis.
    Keywords:  TP53/AMPK/MTOR signaling; autophagy; bronchopulmonary dysplasia; calcitonin gene-related peptide; type II alveolar epithelial cells.
    DOI:  https://doi.org/10.1007/s10753-023-01963-7
  41. Autophagy Rep. 2023 Nov 09. 2(1): 2277584
    MALT-1 shortens lifespan by inhibiting autophagy in the intestine of C. elegans.
    Julie Vérièpe-Salerno, Silvia Podavini, Marcus J C Long, Irina Kolotuev, Muriel Cuendet, Margot Thome.
      The caspase-like protease MALT1 promotes immune responses and oncogenesis in mammals by activating the transcription factor NF-κB. MALT1 is remarkably conserved from mammals to simple metazoans devoid of NF-κB homologs, like the nematode C. elegans. To discover more ancient, NF-κB -independent MALT1 functions, we analysed the phenotype of C. elegans upon silencing of MALT-1 expression systemically or in a tissue-specific manner. MALT-1 silencing in the intestine caused a significant increase in life span, whereas intestinal overexpression of MALT-1 shortened life expectancy. Interestingly, MALT-1-deficient animals showed higher constitutive levels of autophagy in the intestine, which were particularly evident in aged or starved nematodes. Silencing of the autophagy regulators ATG-13, BEC-1 or LGG-2, but not the TOR homolog LET-363, reversed lifespan extension caused by MALT-1 deficiency. These findings suggest that MALT-1 limits the lifespan of C. elegans by acting as an inhibitor of an early step of autophagy in the intestine.
    Keywords:  ATG-13; Aging; Beclin-1; LGG-2; autolysosome; autophagosome; chloroquine; electron microscopy; lifespan; starvation
    DOI:  https://doi.org/10.1080/27694127.2023.2277584
  42. Nat Commun. 2024 Mar 20. 15(1): 2497
    Expression of ALS-PFN1 impairs vesicular degradation in iPSC-derived microglia.
    Salome Funes, Jonathan Jung, Del Hayden Gadd, Michelle Mosqueda, Jianjun Zhong, Shankaracharya, Matthew Unger, Karly Stallworth, Debra Cameron, Melissa S Rotunno, Pepper Dawes, Megan Fowler-Magaw, Pamela J Keagle, Justin A McDonough, Sivakumar Boopathy, Miguel Sena-Esteves, Jeffrey A Nickerson, Cathleen Lutz, William C Skarnes, Elaine T Lim, Dorothy P Schafer, Francesca Massi, John E Landers, Daryl A Bosco.
      Microglia play a pivotal role in neurodegenerative disease pathogenesis, but the mechanisms underlying microglia dysfunction and toxicity remain to be elucidated. To investigate the effect of neurodegenerative disease-linked genes on the intrinsic properties of microglia, we studied microglia-like cells derived from human induced pluripotent stem cells (iPSCs), termed iMGs, harboring mutations in profilin-1 (PFN1) that are causative for amyotrophic lateral sclerosis (ALS). ALS-PFN1 iMGs exhibited evidence of lipid dysmetabolism, autophagy dysregulation and deficient phagocytosis, a canonical microglia function. Mutant PFN1 also displayed enhanced binding affinity for PI3P, a critical signaling molecule involved in autophagic and endocytic processing. Our cumulative data implicate a gain-of-toxic function for mutant PFN1 within the autophagic and endo-lysosomal pathways, as administration of rapamycin rescued phagocytic dysfunction in ALS-PFN1 iMGs. These outcomes demonstrate the utility of iMGs for neurodegenerative disease research and implicate microglial vesicular degradation pathways in the pathogenesis of these disorders.
    DOI:  https://doi.org/10.1038/s41467-024-46695-w
  43. Cell Signal. 2024 Mar 15. pii: S0898-6568(24)00112-8. [Epub ahead of print]118 111144
    The regulatory role of miRNA and lncRNA on autophagy in diabetic nephropathy.
    Siming Yu, Yue Li, Xinxin Lu, Zehui Han, Chunsheng Li, Xingxing Yuan, Dandan Guo.
      Diabetic nephropathy (DN) is a serious complication of diabetes that causes glomerular sclerosis and end-stage renal disease, leading to ascending morbidity and mortality in diabetic patients. Excessive accumulation of aberrantly modified proteins or damaged organelles, such as advanced glycation end-products, dysfunctional mitochondria, and inflammasomes is associated with the pathogenesis of DN. As one of the main degradation pathways, autophagy recycles toxic substances to maintain cellular homeostasis and autophagy dysregulation plays a crucial role in DN progression. MicroRNA (miRNA) and long non-coding RNA (lncRNA) are non-coding RNA (ncRNA) molecules that regulate gene expression and have been implicated in both physiological and pathological conditions. Recent studies have revealed that autophagy-regulating miRNA and lncRNA have been involved in pathological processes of DN, including renal cell injury, mitochondrial dysfunction, inflammation, and renal fibrosis. This review summarizes the role of autophagy in DN and emphasizes the modulation of miRNA and lncRNA on autophagy during disease progression, for the development of promising interventions by targeting these ncRNAs in this disease.
    Keywords:  Autophagy; Diabetic nephropathy; Therapy; lncRNA; miRNA
    DOI:  https://doi.org/10.1016/j.cellsig.2024.111144
  44. Clin Transl Sci. 2024 Mar;17(3): e13758
    Ischemia-induced cardiac dysfunction is exacerbated in adiponectin-knockout mice due to impaired autophagy flux.
    Hye Kyoung Sung, Jialing Tang, James Won Suk Jahng, Erfei Song, Yee Kwan Chan, Abdul Hadee Lone, Jeffrey Peterson, Ali Abdul-Sater, Gary Sweeney.
      Strategies to enhance autophagy flux have been suggested to improve outcomes in cardiac ischemic models. We explored the role of adiponectin in mediating cardiac autophagy under ischemic conditions induced by permanent coronary artery ligation. We studied the molecular mechanisms underlying adiponectin's cardio-protective effects in adiponectin knockout (Ad-KO) compared with wild-type (WT) mice subjected to ischemia by coronary artery ligation and H9c2 cardiomyocyte cell line exposed to hypoxia. Systemic infusion of a cathepsin-B activatable near-infrared probe as a biomarker for autophagy and detection via noninvasive three-dimensional fluorescence molecular tomography combined with computerized tomography to quantitate temporal changes, indicated increased activity in the myocardium of WT mice after myocardial infarction which was attenuated in Ad-KO. Seven days of ischemia increased myocardial adiponectin accumulation and elevated ULK1/AMPK phosphorylation and autophagy assessed by Western blotting for LC3 and p62, an outcome not observed in Ad-KO mice. Cell death, assessed by TUNEL analysis and the ratio of Bcl-2:Bax, plus cardiac dysfunction, measured using echocardiography with strain analysis, were exacerbated in Ad-KO mice. Using cellular models, we observed that adiponectin stimulated autophagy flux in isolated primary adult cardiomyocytes and increased basal and hypoxia-induced autophagy in H9c2 cells. Real-time temporal analysis of caspase-3/7 activation and caspase-3 Western blot indicated that adiponectin suppressed activation by hypoxia. Hypoxia-induced mitochondrial reactive oxygen species production and cell death were also attenuated by adiponectin. Importantly, the ability of adiponectin to reduce caspase-3/7 activation and cell death was not observed in autophagy-deficient cells generated by CRISPR-mediated deletion of Atg7. Collectively, our data indicate that adiponectin acts in an autophagy-dependent manner to attenuate cardiomyocyte caspase-3/7 activation and cell death in response to hypoxia in vitro and ischemia in mice.
    DOI:  https://doi.org/10.1111/cts.13758
  45. Neurol Genet. 2024 Apr;10(2): e200135
    Ectopic HCN4 Provides a Target Biomarker for the Genetic Spectrum of mTORopathies.
    Matthew Coleman, Paulo Pinares-Garcia, Sarah E Stephenson, Wei Shern Lee, Daniz Kooshavar, Catriona A Mclean, Katherine B Howell, Richard J Leventer, Christopher A Reid, Paul J Lockhart.
      Background and Objectives: Pathogenic variants in PI3K-AKT-mTOR pathway and GATOR1 complex genes resulting in hyperactivation of mechanistic target of rapamycin (mTOR) complex 1 are a major cause of drug-resistant epilepsy and focal cortical malformations (FCM). Resective neurosurgery is often required to achieve seizure control in patients with mTORopathies due to lack of effectiveness of nonsurgical therapies, including antiseizure medication and mTOR inhibitors. Elevated hyperpolarization-activated cyclic nucleotide-gated potassium channel isoform 4 (HCN4) has been proposed as a key marker in some mTOR-related brain malformations. This study aimed to investigate HCN4 as a biomarker in the brain across the genetic spectrum of mTORopathies in humans.Methods: Our study investigated the relative steady-state levels and cellular localization of HCN4 in resected human brain tissue from 18 individuals with mTORopathies (3 individuals with tuberous sclerosis complex (TSC) due to TSC2 variants, 5 individuals with focal cortical dysplasia type IIA (FCD IIA) due to genetic variants in MTOR, AKT3, and PIK3CA, and 10 individuals with FCD IIB due to variants in TSC1, MTOR, RHEB, DEPDC5, or NPRL3).
    Results: Elevated HCN4 was observed to be highly restricted to abnormal cell types (dysmorphic neurons and balloon cells) in brain tissue from all mTORopathy tissues (p < 0.0001) compared with those in controls, regardless of genetic cause or variant allele frequency. Elevated HCN4 was not observed in controls or individuals with non-mTOR-related focal epilepsy due to pathogenic variants in ATP1A3, SLC35A2, or FGFR1.
    Discussion: HCN4 provides a biomarker for the genetic spectrum of mTORopathies and may present a potential therapeutic target for seizure control in mTOR-related epilepsy.
    DOI:  https://doi.org/10.1212/NXG.0000000000200135
  46. Biol Res. 2024 Mar 17. 57(1): 10
    YME1L-mediated mitophagy protects renal tubular cells against cellular senescence under diabetic conditions.
    Yuanyuan Luo, Lingxiao Zhang, Ning Su, Lerong Liu, Tongfeng Zhao.
      BACKGROUND: The senescence of renal tubular epithelial cells (RTECs) is crucial in the progression of diabetic kidney disease (DKD). Accumulating evidence suggests a close association between insufficient mitophagy and RTEC senescence. Yeast mitochondrial escape 1-like 1 (YME1L), an inner mitochondrial membrane metalloprotease, maintains mitochondrial integrity. Its functions in DKD remain unclear. Here, we investigated whether YME1L can prevent the progression of DKD by regulating mitophagy and cellular senescence.METHODS: We analyzed YME1L expression in renal tubules of DKD patients and mice, explored transcriptomic changes associated with YME1L overexpression in RTECs, and assessed its impact on RTEC senescence and renal dysfunction using an HFD/STZ-induced DKD mouse model. Tubule-specific overexpression of YME1L was achieved through the use of recombinant adeno-associated virus 2/9 (rAAV 2/9). We conducted both in vivo and in vitro experiments to evaluate the effects of YME1L overexpression on mitophagy and mitochondrial function. Furthermore, we performed LC-MS/MS analysis to identify potential protein interactions involving YME1L and elucidate the underlying mechanisms.
    RESULTS: Our findings revealed a significant decrease in YME1L expression in the renal tubules of DKD patients and mice. However, tubule-specific overexpression of YME1L significantly alleviated RTEC senescence and renal dysfunction in the HFD/STZ-induced DKD mouse model. Moreover, YME1L overexpression exhibited positive effects on enhancing mitophagy and improving mitochondrial function both in vivo and in vitro. Mechanistically, our LC-MS/MS analysis uncovered a crucial mitophagy receptor, BCL2-like 13 (BCL2L13), as an interacting partner of YME1L. Furthermore, YME1L was found to promote the phosphorylation of BCL2L13, highlighting its role in regulating mitophagy.
    CONCLUSIONS: This study provides compelling evidence that YME1L plays a critical role in protecting RTECs from cellular senescence and impeding the progression of DKD. Overexpression of YME1L demonstrated significant therapeutic potential by ameliorating both RTEC senescence and renal dysfunction in the DKD mice. Moreover, our findings indicate that YME1L enhances mitophagy and improves mitochondrial function, potentially through its interaction with BCL2L13 and subsequent phosphorylation. These novel insights into the protective mechanisms of YME1L offer a promising strategy for developing therapies targeting DKD.
    Keywords:  Cellular senescence; Diabetic kidney disease; Mitophagy; Tubular cell; YME1L
    DOI:  https://doi.org/10.1186/s40659-024-00487-0
  47. Trends Cancer. 2024 Mar 21. pii: S2405-8033(24)00044-X. [Epub ahead of print]
    Emerging roles of TBK1 in cancer immunobiology.
    Alex Miranda, Carl A Shirley, Russell W Jenkins.
      TANK-binding kinase 1 (TBK1) is a versatile serine/threonine protein kinase with established roles in innate immunity, metabolism, autophagy, cell death, and inflammation. While best known for its role in regulating innate immunity, TBK1 has emerged as a cancer cell-intrinsic immune evasion gene by virtue of its role in modulating cellular responses to inflammatory signals emanating from the immune system. Beyond its effect on cancer cells, TBK1 appears to regulate lymphoid and myeloid cells in the tumor immune microenvironment. In this review, we detail recent advances in our understanding of the tumor-intrinsic and -extrinsic roles and regulation of TBK1 in tumor immunity.
    Keywords:  RIPK1; TBK1; cell death; immunotherapy
    DOI:  https://doi.org/10.1016/j.trecan.2024.02.007
  48. J Biol Chem. 2024 Mar 20. pii: S0021-9258(24)01701-0. [Epub ahead of print] 107206
    Dual-specificity kinase DYRK3 phosphorylates p62 at the Thr-269 residue and promotes melanoma progression.
    Ye Hyung Lee, A-Rum Yoon, Chae-Ok Yun, Kwang Chul Chung.
      Melanoma is a type of skin cancer that originates in melanin-producing melanocytes. It is considered a multifactorial disease caused by both genetic and environmental factors, such as UV radiation. Dual-specificity tyrosine-phosphorylation-regulated kinase (DYRK) phosphorylates many substrates involved in signaling pathways, cell survival, cell cycle control, differentiation, and neuronal development. However, little is known about the cellular function of DYRK3, one of the five members of the DYRK family. Interestingly, it was observed that the expression of DYRK3, as well as p62 (a multifunctional signaling protein), is highly enhanced in most melanoma cell lines. This study aimed to investigate whether DYRK3 interacts with p62, and how this affects melanoma progression, particularly in melanoma cell lines. We found that DYRK3 directly phosphorylates p62 at the Ser-207 and Thr-269 residue. Phosphorylation at Thr-269 of p62 by DYRK3 increased the interaction of p62 with TRAF6, an already known activator of mTORC1 in the mTOR-involved signaling pathways. Moreover, the phosphorylation of p62 at Thr-269 promoted the activation of mTORC1. We also found that DYRK3-mediated phosphorylation of p62 at Thr-269 enhanced the growth of melanoma cell lines and melanoma progression. Conversely, DYRK3 knockdown or blockade of p62-T269 phosphorylation inhibited melanoma growth, colony formation, and cell migration. In conclusion, we demonstrated that DYRK3 phosphorylates p62, positively modulating the p62-TRAF6-mTORC1 pathway in melanoma cells. This finding suggests that DYRK3 suppression may be a novel therapy for preventing melanoma progression by regulating the mTORC1 pathway.
    Keywords:  DYRK3; Melanoma; Phosphorylation; TRAF6; mTORC1; p62
    DOI:  https://doi.org/10.1016/j.jbc.2024.107206
  49. Cell Death Discov. 2024 Mar 15. 10(1): 142
    PLEKHM2 deficiency induces impaired mitochondrial clearance and elevated ROS levels in human iPSC-derived cardiomyocytes.
    Jianchao Zhang, Ying Peng, Wanrong Fu, Ruifei Wang, Jinhua Cao, Shuang Li, Xiaoxu Tian, Zhonggen Li, Chongpei Hua, Yafei Zhai, Yangyang Liu, Mengduan Liu, Jihong Sun, Xiaowei Li, Xiaoyan Zhao, Jianzeng Dong.
      Pleckstrin homology domain-containing family M member 2 (PLEKHM2) is an essential adaptor for lysosomal trafficking and its homozygous truncation have been reported to cause early onset dilated cardiomyopathy (DCM). However, the molecular mechanism of PLEKHM2 deficiency in DCM pathogenesis and progression is poorly understood. Here, we generated an in vitro model of PLEKHM2 knockout (KO) induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) to elucidate the potential pathogenic mechanism of PLEKHM2-deficient cardiomyopathy. PLEKHM2-KO hiPSC-CMs developed disease phenotypes with reduced contractility and impaired calcium handling. Subsequent RNA sequencing (RNA-seq) analysis revealed altered expression of genes involved in mitochondrial function, autophagy and apoptosis in PLEKHM2-KO hiPSC-CMs. Further molecular experiments confirmed PLEKHM2 deficiency impaired autophagy and resulted in accumulation of damaged mitochondria, which triggered increased reactive oxygen species (ROS) levels and decreased mitochondrial membrane potential (Δψm). Importantly, the elevated ROS levels caused oxidative stress-induced damage to nearby healthy mitochondria, resulting in extensive Δψm destabilization, and ultimately leading to impaired mitochondrial function and myocardial contractility. Moreover, ROS inhibition attenuated oxidative stress-induced mitochondrial damage, thereby partially rescued PLEKHM2 deficiency-induced disease phenotypes. Remarkably, PLEKHM2-WT overexpression restored autophagic flux and rescued mitochondrial function and myocardial contractility in PLEKHM2-KO hiPSC-CMs. Taken together, these results suggested that impaired mitochondrial clearance and increased ROS levels play important roles in PLEKHM2-deficient cardiomyopathy, and PLEKHM2-WT overexpression can improve mitochondrial function and rescue PLEKHM2-deficient cardiomyopathy.
    DOI:  https://doi.org/10.1038/s41420-024-01907-6
  50. Sci Rep. 2024 03 18. 14(1): 6504
    The roles of autophagy, ferroptosis and pyroptosis in the anti-ovarian cancer mechanism of harmine and their crosstalk.
    Jun Zhu, Hong Zhu, Qing Zhu, Shi Lei Xu, Lu Xiao, Ming Yue Zhang, Jun Gao.
      This study aimed to investigate the role of autophagy, ferroptosis, and pyroptosis in the antitumour mechanism of harmine (Har) and its crosstalk in ovarian cancer. By transmission electron microscopy, we found that compared with those in the control group, the cytoplasm of human ovarian cancer cells (SKOV3) treated with Har showed increased numbers of autophagic vesicles, decreased intracellular mitochondrial volume, increased bilayer membrane density, and decreased cristae. Western blot, immunofluorescence, and monodasylcadaverine (MDC) staining all suggested that Har promoted autophagy in SKOV3 cells. LY294002 and siFOXO3 rescued the inhibition of the PI3K/AKT/mTOR/FOXO3 signalling pathway and the promotion of autophagy by Har. Additionally, the levels of ferroptosis- and pyroptosis-related proteins and the levels of Fe2+ , glutathione (GSH), malondialdehyde (MDA), and superoxide dismutase (SOD) suggested that Har promoted ferroptosis and pyroptosis in SKOV3 cells. Interestingly, pretreatment with chloroquine (CQ), erastin, rapamycin (Rap), or ferrostatin-1 (Fer-1) increased or reversed the ferroptosis and pyroptosis promoted by Har, respectively. In vivo, the volume of tumours in the Har group was decreased, and immunohistochemistry revealed decreased levels of Ki-67 and GPX4 and increased levels of ATG5 and NARL3. In conclusion, Har exerts its anti-ovarian cancer effect not only by promoting autophagy by regulating the PI3K/AKT/mTOR/FOXO3 signalling pathway but also by promoting ferroptosis and pyroptosis. Additionally, there is complex crosstalk between autophagy, ferroptosis, and pyroptosis in ovarian cancer.
    DOI:  https://doi.org/10.1038/s41598-024-57196-7
  51. IUBMB Life. 2024 Mar 18.
    Autophagy inhibition potentiates energy restriction-induced cell death in hepatocellular carcinoma cells.
    Sara M Elgendy, Dana M Zaher, Nadin H Sarg, Nour N Abu Jayab, Dima W Alhamad, Taleb H Al-Tel, Hany A Omar.
      Hepatocellular carcinoma (HCC) significantly contributes to cancer-related mortality due to the limited response of HCC to current anticancer therapies, thereby necessitating more effective treatment approaches. Energy restriction mimetic agents (ERMAs) have emerged as potential therapies in targeting the Warburg effect, a unique metabolic process in cancer cells. However, ERMAs exhibit limited efficacy when used as monotherapy. Additionally, ERMAs have been found to induce autophagy in cancer cells. The role of autophagy in cancer survival remains a subject of debate. Thus, it is crucial to ascertain whether ERMA-induced autophagy is a mechanism for cell survival or cell death in HCC. Our study aims to investigate the effect of autophagy inhibition on the survival of HCC cells treated with ERMAs while also examining the potential of combining an autophagy inhibitor such as spautin-1 with ERMAs to enhance HCC cell death. Our results suggest a cytoprotective role for ERMA-induced autophagy in HCC cells, as combining the autophagy inhibitor spautin-1 with ERMAs effectively suppressed ERMA-induced autophagy and synergistically enhanced their antitumor activity. The treatment combination promoted HCC death through apoptosis, cell cycle arrest, and inhibition of AKT and ERK activation, which are known to play a key role in cellular proliferation. Collectively, our findings highlight a potential strategy to combat HCC by combining energy restriction with autophagy inhibition.
    Keywords:  ERMA; autophagy; glucose restriction; hepatocellular carcinoma; spautin-1
    DOI:  https://doi.org/10.1002/iub.2816
  52. Mol Cell. 2024 Mar 21. pii: S1097-2765(24)00168-0. [Epub ahead of print]84(6): 995-997
    Integrating the response to stressed mitochondria.
    Elliot Dine, Richard J Youle.
      Chakrabarty et al.1 demonstrate that phospho-EIF2α (pEIF2α), the translation initiation factor that mediates the integrated stress response (ISR), is necessary and sufficient for the autophagic degradation of mitochondria following the addition of mitochondrial stressors.
    DOI:  https://doi.org/10.1016/j.molcel.2024.02.026
  53. J Exp Med. 2024 May 06. pii: e20221190. [Epub ahead of print]221(5):
    A TBK1 variant causes autophagolysosomal and motoneuron pathology without neuroinflammation in mice.
    David Brenner, Kirsten Sieverding, Jahnavi Srinidhi, Susanne Zellner, Christopher Secker, Rüstem Yilmaz, Julia Dyckow, Shady Amr, Anna Ponomarenko, Esra Tunaboylu, Yasmin Douahem, Joana S Schlag, Lucía Rodríguez Martínez, Georg Kislinger, Cornelia Niemann, Karsten Nalbach, Wolfgang P Ruf, Jonathan Uhl, Johanna Hollenbeck, Lucas Schirmer, Alberto Catanese, Christian S Lobsiger, Karin M Danzer, Deniz Yilmazer-Hanke, Christian Münch, Philipp Koch, Axel Freischmidt, Martina Fetting, Christian Behrends, Rosanna Parlato, Jochen H Weishaupt.
      Heterozygous mutations in the TBK1 gene can cause amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The majority of TBK1-ALS/FTD patients carry deleterious loss-of-expression mutations, and it is still unclear which TBK1 function leads to neurodegeneration. We investigated the impact of the pathogenic TBK1 missense variant p.E696K, which does not abolish protein expression, but leads to a selective loss of TBK1 binding to the autophagy adaptor protein and TBK1 substrate optineurin. Using organelle-specific proteomics, we found that in a knock-in mouse model and human iPSC-derived motor neurons, the p.E696K mutation causes presymptomatic onset of autophagolysosomal dysfunction in neurons precipitating the accumulation of damaged lysosomes. This is followed by a progressive, age-dependent motor neuron disease. Contrary to the phenotype of mice with full Tbk1 knock-out, RIPK/TNF-α-dependent hepatic, neuronal necroptosis, and overt autoinflammation were not detected. Our in vivo results indicate autophagolysosomal dysfunction as a trigger for neurodegeneration and a promising therapeutic target in TBK1-ALS/FTD.
    DOI:  https://doi.org/10.1084/jem.20221190
  54. Curr Probl Cardiol. 2024 Mar 16. pii: S0146-2806(24)00158-0. [Epub ahead of print]49(5): 102519
    Association between serum beclin 1 level and cardiac valvular calcification in hemodialysis patients.
    Hayam Ahmed Hebah, Hadeer Moamen Kamel, Islam Mahmoud Bastawy, Fatma Abdelrahman Ahmed.
      BACKGROUND: Cardiovascular calcification is a pervasive issue throughout chronic kidney disease (CKD) progression. Autophagy, a fundamental cellular process, exerts significant influence on various cardiac pathologies, including arrhythmias, atherosclerosis, heart failure, and notably, valvular, and vascular calcifications. Beclin-1, a crucial eukaryotic protein, plays a major regulatory role in autophagy as part of the phosphatidylinositol-3-kinase (PI3K) complex. Recent evidence suggests a protective role for Beclin-1-mediated autophagy in CKD vascular calcification, raising its potential as a novel therapeutic target in this context.WE AIMED TO: Investigate the association between serum Beclin 1 levels and the presence of cardiovascular valvular calcification in hemodialysis patients.
    RESULTS: This study evaluated a cohort of 102 hemodialysis patients, evenly divided into two groups based on echocardiographic findings. All participants underwent serum Beclin 1 measurement and transthoracic echocardiography. Patients with acute kidney injury, active malignancy, or diabetes were excluded. Our study revealed significant differences between the two groups in terms of: Serum Beclin 1 levels, all parameters of lipid profile, prevalence of ischemic heart disease, serum albumin levels and Total calcium. Echocardiography in Group 1 showed that most cases (60.78%) exhibited mild aortic valve calcification. Additionally, significant relationships were observed between Beclin 1 and: ischemic heart disease (p=0.011) Aortic valve calcification on echocardiography (p < 0.001) Interestingly, lower Beclin 1 levels were associated with more severe valve calcification. A Beclin 1 cutoff value of ≤ 35.5 ng/ml demonstrated the highest sensitivity (98%) and specificity (92%).
    CONCLUSION: Our findings suggest that the serum Beclin 1 level could be incorporated into a predictive model for cardiac valvular calcification in hemodialysis patients.
    Keywords:  Autophagy; Beclin 1; CKD; Hemodialysis; Valvular calcification
    DOI:  https://doi.org/10.1016/j.cpcardiol.2024.102519
  55. Cell Death Differ. 2024 Mar 21.
    Retinoblastoma-associated protein is important for TRIM24-mediated activation of the mTOR signaling pathway through DUSP2 action in prostate cancer.
    Da Ren, Wei Li, Ruijiang Zeng, Xinlin Liu, Huaiyuan Liang, Wei Xiong, Chunguang Yang, Xin Jin.
      RB transcriptional corepressor 1 (RB) deletion is the most important genomic factor associated with the prognosis of castration-resistant prostate cancer (CRPC) patients receiving androgen receptor (AR) signaling inhibitor therapy. Loss of RB could support prostate cancer cell growth in a hormone-independent manner, but the underlying mechanism by which RB regulates tumor progression extends far beyond the cell cycle pathway. A previous study indicated that RB inactivates AKT signaling but has no effect on mTOR signaling in cancer cells. Here, we found that the S249/T252 site in RB is key to regulating the transcriptional activity of the tumor-promoting factor TRIM24 in CRPC, as identified through FXXXV mapping. The RB/TRIM24 complex functions through DUSP2, which serves as an intermediate bridge, to activate the mTOR pathway and promote prostate cancer progression. Accordingly, we designed RB-linker-proteolysis-targeting chimera (PROTAC) molecules, which decreased TRIM24 protein levels and inactivated the mTOR signaling pathway, thereby inhibiting prostate cancer. Therefore, this study not only elucidates the novel function of RB but also provides a theoretical basis for the development of new drugs for treating prostate cancer.
    DOI:  https://doi.org/10.1038/s41418-024-01282-w
  56. Chemistry. 2024 Mar 20. e202400808
    A pH-Sensitive Double Chromophore Fluorescent Dye for Live-Tracking of Lipophagy.
    Pascal M Engelhardt, Matteo Veronese, Alpay A Eryigit, Anushka Das, Alexander T Kaczmarek, Elena I Rugarli, Hans-Günther Schmalz.
      Lipid droplet (LD) degradation provides metabolic energy and important building blocks for various cellular processes. The two major LD degradation pathways include autophagy (lipophagy), which involves delivery of LDs to autolysosomes, and lipolysis, which is mediated by lipases. While abnormalities in LD degradation are associated with various pathological disorders, our understanding of lipophagy is still rudimentary. In this study, we describe the development of a lipophilic dye containing two fluorophores, one of which is pH-sensitive and the other pH-stable. We further demonstrate that this "Lipo-Fluddy" can be used to visualize and quantify lipophagy in living cells, in an easily applicable and protein label-free approach. After estimating the ability of compound candidates to penetrate LDs, we synthesized several BODIPY and (pH-switchable) rhodol dyes, whose fluorescence properties (incl. their photophysical compatibility) were analyzed. Of three Lipo-Fluddy dyes synthesized, one exhibited the desired properties and allowed observation of lipophagy by fluorescence microscopy. Also, this dye proved to be non-toxic and suitable for the examination of various cell lines. A method was developed to quantify the lipophagy process using flow cytometry, which could be applied in the future in the identification of lipophagy-related genes or in the screening of potential drugs against lipophagy-related diseases.
    Keywords:  BODIPY; Fluorescence Microscopy; Lipid-related diseases; Lipophagy; Switchable dyes
    DOI:  https://doi.org/10.1002/chem.202400808
This page is being maintained by Thomas Krichel. It was last updated on 2024‒03‒24 at 12:04.