bims-mepmim 2023-11-05 papers

bims-mepmim

Biomed News

on Metabolites in pathological microenvironments and immunometabolism

Issue of 2023‒11‒05
28 papers selected by
Erika Mariana Palmieri, NIH/NCI Laboratory of Cancer ImmunoMetabolism

Autoregulatory control of mitochondrial glutathione homeostasis.
The 'non-essential' amino acid cysteine is required to prevent ferroptosis in acute myeloid leukemia.
Farnesoid X receptor activation by bile acids suppresses lipid peroxidation and ferroptosis.
Bacterial indole-3-lactic acid affects epithelium-macrophage crosstalk to regulate intestinal homeostasis.
Hepatocyte FBXW7-dependent activity of nutrient-sensing nuclear receptors controls systemic energy homeostasis and NASH progression in male mice.
The PNPLA3 I148M variant increases ketogenesis and decreases hepatic de novo lipogenesis and mitochondrial function in humans.
Blood flow patterns switch VEGFR2 activity through differential S-nitrosylation and S-oxidation.
PDK4-dependent hypercatabolism and lactate production of senescent cells promotes cancer malignancy.
Lipidome and metabolome analyses reveal metabolic alterations associated with MCF-7 apoptosis upon 4-hydroxytamoxifen treatment.
The Lin28b/Wnt5a axis drives pancreas cancer through crosstalk between cancer associated fibroblasts and tumor epithelium.
GLUT3 regulates alternative macrophage signaling through a glucose transport-independent role.
Real-time resolution studies of the regulation of pyruvate-dependent lactate metabolism by hexokinases in single cells.
A tuft cell - ILC2 signaling circuit provides therapeutic targets to inhibit gastric metaplasia and tumor development.
Nitric oxide and thiols: Chemical biology, signaling paradigms, and vascular therapeutic potential.
Metabolomic rewiring promotes endocrine therapy resistance in breast cancer.
Mitochondrial hydrogen peroxide production by pyruvate dehydrogenase (PDH) and α-ketoglutarate dehydrogenase (KGDH) in oxidative eustress and oxidative distress.
Metabolic pathway analysis using stable isotopes in patients with cancer.
LPGAT1 controls MEGDEL syndrome by coupling phosphatidylglycerol remodeling with mitochondrial transport.
Hyperinsulinemia acts via acinar insulin receptors to initiate pancreatic cancer by increasing digestive enzyme production and inflammation.
Signaling metabolite succinylacetone activates HIF-1α and promotes angiogenesis in GSTZ1-deficient hepatocellular carcinoma.
Caveolin-1 mediates the utilization of extracellular proteins for survival in refractory gastric cancer.
Molecular Mechanism of Fasting-Mimicking Diet in Inhibiting Colorectal Cancer Progression: Implications for Immune Therapy and Metabolic Regulation.
Cancer-associated fibroblasts actively compress cancer cells and modulate mechanotransduction.
Hepatic conversion of acetyl-CoA to acetate plays crucial roles in energy stress.
Metabolic regulation in erythroid differentiation by systemic ketogenesis in fasted mice.
RCCD1 promotes breast carcinogenesis through regulating hypoxia-associated mitochondrial homeostasis.
CSF1R-dependent macrophages in the salivary gland are essential for epithelial regeneration after radiation-induced injury.
Tumor-specific GPX4 degradation enhances ferroptosis-initiated antitumor immune response in mouse models of pancreatic cancer.

Science. 2023 Nov 02. eadf4154

Autoregulatory control of mitochondrial glutathione homeostasis.

Yuyang Liu, Shanshan Liu, Anju Tomar, Frederick S Yen, Gokhan Unlu, Nathalie Ropek, Ross A Weber, Ying Wang, Artem Khan, Mark Gad, Junhui Peng, Erdem Terzi, Hanan Alwaseem, Alexandra E Pagano, Søren Heissel, Henrik Molina, Benjamin Allwein, Timothy C Kenny, Richard L Possemato, Li Zhao, Richard K Hite, Ekaterina V Vinogradova, Sheref S Mansy, Kıvanç Birsoy.

Mitochondria must maintain adequate amounts of metabolites for protective and biosynthetic functions. However, how mitochondria sense the abundance of metabolites and regulate metabolic homeostasis is not well understood. We focused on glutathione (GSH), a critical redox metabolite in mitochondria and identified a feedback mechanism that controls its abundance through the mitochondrial GSH transporter, SLC25A39. Under physiological conditions, SLC25A39 is rapidly degraded by a mitochondrial protease, AFG3L2. Depletion of GSH dissociates AFG3L2 from SLC25A39, causing a compensatory increase in mitochondrial GSH uptake. Genetic and proteomic analysis identified a putative iron-sulfur cluster in the matrix-facing loop of SLC25A39 to be essential for this regulation, coupling mitochondrial iron homeostasis to GSH import. Altogether, our work revealed a paradigm for the autoregulatory control of metabolic homeostasis in organelles.

DOI: https://doi.org/10.1126/science.adf4154
Blood Adv. 2023 Oct 31. pii: bloodadvances.2023010786. [Epub ahead of print]

The 'non-essential' amino acid cysteine is required to prevent ferroptosis in acute myeloid leukemia.

Alan Cunningham, Lieve Oudejans, Marjan Geugien, Diego A Pereira-Martins, Albertus Tj Wierenga, Ayşegül Erdem, Dominique Sternadt, Gerwin A Huls, Jan Jacob Schuringa.

Cysteine is a non-essential amino acid required for protein synthesis, the generation of the anti-oxidant glutathione and for synthesizing the non-proteinogenic amino acid taurine. Here, we highlight the broad sensitivity of leukemic stem and progenitor cells to cysteine depletion. By CRISPR/Cas9-mediated knockout of cystathionine-γ-Lysase (CTH), the cystathionine to cysteine converting enzyme, and by metabolite supplementation studies upstream of cysteine, we functionally prove that cysteine is not synthesized from methionine in acute myeloid leukemia (AML) cells. Therefore, while perhaps nutritionally non-essential, cysteine must be imported for survival of these specific cell types. Depletion of cyst(e)ine increased reactive oxygen species (ROS) levels and cell death was induced predominantly as a consequence of glutathione deprivation. NADPH oxidase (NOX) inhibition strongly rescued viability following cysteine depletion, highlighting this as an important source of ROS in AML. ROS-induced cell death was mediated via ferroptosis, and inhibition of GPX4, which functions to reduce lipid peroxides, was also highly toxic and we therefore propose that GPX4 is likely key in mediating the antioxidant activity of glutathione. In line, inhibition of the ROS scavenger thioredoxin reductase with Auranofin also impaired cell viability, whereby we find that in particular OXPHOS-driven AML subtypes are highly dependent on thioredoxin-mediated protection against ferroptosis. While inhibition of the cystine importer xCT with Sulfasalazine was ineffective as a monotherapy, its combination with L-buthionine-sulfoximine (BSO) further improved AML ferroptosis induction. We propose the combination of either Sulfasalazine or anti-oxidant machinery inhibitors along with ROS inducers such as BSO or chemotherapy for further pre-clinical testing.

DOI: https://doi.org/10.1182/bloodadvances.2023010786
Nat Commun. 2023 Oct 30. 14(1): 6908

Farnesoid X receptor activation by bile acids suppresses lipid peroxidation and ferroptosis.

Juliane Tschuck, Lea Theilacker, Ina Rothenaigner, Stefanie A I Weiß, Banu Akdogan, Van Thanh Lam, Constanze Müller, Roman Graf, Stefanie Brandner, Christian Pütz, Tamara Rieder, Philippe Schmitt-Kopplin, Michelle Vincendeau, Hans Zischka, Kenji Schorpp, Kamyar Hadian.

Ferroptosis is a regulated cell death modality that occurs upon iron-dependent lipid peroxidation. Recent research has identified many regulators that induce or inhibit ferroptosis; yet, many regulatory processes and networks remain to be elucidated. In this study, we performed a chemical genetics screen using small molecules with known mode of action and identified two agonists of the nuclear receptor Farnesoid X Receptor (FXR) that suppress ferroptosis, but not apoptosis or necroptosis. We demonstrate that in liver cells with high FXR levels, knockout or inhibition of FXR sensitized cells to ferroptotic cell death, whereas activation of FXR by bile acids inhibited ferroptosis. Furthermore, FXR inhibited ferroptosis in ex vivo mouse hepatocytes and human hepatocytes differentiated from induced pluripotent stem cells. Activation of FXR significantly reduced lipid peroxidation by upregulating the ferroptosis gatekeepers GPX4, FSP1, PPARα, SCD1, and ACSL3. Together, we report that FXR coordinates the expression of ferroptosis-inhibitory regulators to reduce lipid peroxidation, thereby acting as a guardian of ferroptosis.

DOI: https://doi.org/10.1038/s41467-023-42702-8
Proc Natl Acad Sci U S A. 2023 Nov 07. 120(45): e2309032120

Bacterial indole-3-lactic acid affects epithelium-macrophage crosstalk to regulate intestinal homeostasis.

Kaiyuan Yu, Qianqian Li, Xuan Sun, Xianping Peng, Qiang Tang, Hongyu Chu, Lu Zhou, Bangmao Wang, Zhemin Zhou, Xueqin Deng, Jianming Yang, Junqiang Lv, Ran Liu, Chunhui Miao, Wei Zhao, Zhi Yao, Quan Wang.

  Tryptophan and its derivatives perform a variety of biological functions; however, the role and specific mechanism of many tryptophan derivatives in intestinal inflammation remain largely unclear. Here, we identified that an Escherichia coli strain (Ec-TMU) isolated from the feces of tinidazole-treated individuals, and indole-3-lactic acid (ILA) in its supernatant, decreased the susceptibility of mice to dextran sulfate sodium-induced colitis. Ec-TMU and ILA contribute to the relief of colitis by inhibiting the production of epithelial CCL2/7, thereby reducing the accumulation of inflammatory macrophages in vitro and in vivo. Mechanistically, ILA downregulates glycolysis, NF-κB, and HIF signaling pathways via the aryl hydrocarbon receptor, resulting in decreased CCL2/7 production in epithelial cells. Clinical evidence suggests that the fecal ILA level is negatively correlated with the progression indicator of inflammatory bowel diseases. These results demonstrate that ILA has the potential to regulate intestinal homeostasis by modulating epithelium-macrophage interactions.

Keywords:  CCL2/7; CCR2; ILA; intestinal homeostasis; macrophage

DOI:  https://doi.org/10.1073/pnas.2309032120
Nat Commun. 2023 Nov 01. 14(1): 6982

Hepatocyte FBXW7-dependent activity of nutrient-sensing nuclear receptors controls systemic energy homeostasis and NASH progression in male mice.

Hui Xia, Catherine R Dufour, Younes Medkour, Charlotte Scholtes, Yonghong Chen, Christina Guluzian, Wafa B'chir, Vincent Giguère.

Nonalcoholic steatohepatitis (NASH) is epidemiologically associated with obesity and diabetes and can lead to liver cirrhosis and hepatocellular carcinoma if left untreated. The intricate signaling pathways that orchestrate hepatocyte energy metabolism and cellular stress, intrahepatic cell crosstalk, as well as interplay between peripheral tissues remain elusive and are crucial for the development of anti-NASH therapies. Herein, we reveal E3 ligase FBXW7 as a key factor regulating hepatic catabolism, stress responses, systemic energy homeostasis, and NASH pathogenesis with attenuated FBXW7 expression as a feature of advanced NASH. Multiomics and pharmacological intervention showed that FBXW7 loss-of-function in hepatocytes disrupts a metabolic transcriptional axis conjointly controlled by the nutrient-sensing nuclear receptors ERRα and PPARα, resulting in suppression of fatty acid oxidation, elevated ER stress, apoptosis, immune infiltration, fibrogenesis, and ultimately NASH progression in male mice. These results provide the foundation for developing alternative strategies co-targeting ERRα and PPARα for the treatment of NASH.

DOI: https://doi.org/10.1038/s41467-023-42785-3
Cell Metab. 2023 Oct 20. pii: S1550-4131(23)00377-7. [Epub ahead of print]

The PNPLA3 I148M variant increases ketogenesis and decreases hepatic de novo lipogenesis and mitochondrial function in humans.

Panu K Luukkonen, Kimmo Porthan, Noora Ahlholm, Fredrik Rosqvist, Sylvie Dufour, Xian-Man Zhang, Tiina E Lehtimäki, Wenla Seppänen, Marju Orho-Melander, Leanne Hodson, Kitt Falk Petersen, Gerald I Shulman, Hannele Yki-Järvinen.

  The PNPLA3 I148M variant is the major genetic risk factor for all stages of fatty liver disease, but the underlying pathophysiology remains unclear. We studied the effect of this variant on hepatic metabolism in homozygous carriers and non-carriers under multiple physiological conditions with state-of-the-art stable isotope techniques. After an overnight fast, carriers had higher plasma β-hydroxybutyrate concentrations and lower hepatic de novo lipogenesis (DNL) compared to non-carriers. After a mixed meal, fatty acids were channeled toward ketogenesis in carriers, which was associated with an increase in hepatic mitochondrial redox state. During a ketogenic diet, carriers manifested increased rates of intrahepatic lipolysis, increased plasma β-hydroxybutyrate concentrations, and decreased rates of hepatic mitochondrial citrate synthase flux. These studies demonstrate that homozygous PNPLA3 I148M carriers have hepatic mitochondrial dysfunction leading to reduced DNL and channeling of carbons to ketogenesis. These findings have implications for understanding why the PNPLA3 variant predisposes to progressive liver disease.

Keywords:  GDF-15; NAD+; NADH; NAFLD; NASH; ketogenic diet; mitochondrial dysfunction; patatin-like phospholipase domain containing protein 3; redox; reductive stress

DOI:  https://doi.org/10.1016/j.cmet.2023.10.008
Cell Rep. 2023 Oct 31. pii: S2211-1247(23)01373-6. [Epub ahead of print]42(11): 113361

Blood flow patterns switch VEGFR2 activity through differential S-nitrosylation and S-oxidation.

Dong Hoon Kang, Yerin Kim, Seongchun Min, Su Youn Lee, Ka Young Chung, In-Jeoung Baek, Kihwan Kwon, Hanjoong Jo, Sang Won Kang.

  Vascular endothelial growth factor receptor-2 (VEGFR2) plays a key role in maintaining vascular endothelial homeostasis. Here, we show that blood flows determine activation and inactivation of VEGFR2 through selective cysteine modifications. VEGFR2 activation is regulated by reversible oxidation at Cys1206 residue. H2O2-mediated VEGFR2 oxidation is induced by oscillatory flow in vascular endothelial cells through the induction of NADPH oxidase-4 expression. In contrast, laminar flow induces the expression of endothelial nitric oxide synthase and results in the S-nitrosylation of VEGFR2 at Cys1206, which counteracts the oxidative inactivation. The shear stress model study reveals that disturbed blood flow operated by partial ligation in the carotid arteries induces endothelial damage and intimal hyperplasia in control mice but not in knock-in mice harboring the oxidation-resistant mutant (C1206S) of VEGFR2. Thus, our findings reveal that flow-dependent redox regulation of the VEGFR2 kinase is critical for the structural and functional integrity of the arterial endothelium.

Keywords:  CP: Cell biology; NOX4; VEGFR2; endothelial NOS; endothelial cells; shear stress

DOI:  https://doi.org/10.1016/j.celrep.2023.113361
Nat Metab. 2023 Oct 30.

PDK4-dependent hypercatabolism and lactate production of senescent cells promotes cancer malignancy.

Xuefeng Dou, Qiang Fu, Qilai Long, Shuning Liu, Yejun Zou, Da Fu, Qixia Xu, Zhirui Jiang, Xiaohui Ren, Guilong Zhang, Xiaoling Wei, Qingfeng Li, Judith Campisi, Yuzheng Zhao, Yu Sun.

Senescent cells remain metabolically active, but their metabolic landscape and resulting implications remain underexplored. Here, we report upregulation of pyruvate dehydrogenase kinase 4 (PDK4) upon senescence, particularly in some stromal cell lines. Senescent cells display a PDK4-dependent increase in aerobic glycolysis and enhanced lactate production but maintain mitochondrial respiration and redox activity, thus adopting a special form of metabolic reprogramming. Medium from PDK4+ stromal cells promotes the malignancy of recipient cancer cells in vitro, whereas inhibition of PDK4 causes tumor regression in vivo. We find that lactate promotes reactive oxygen species production via NOX1 to drive the senescence-associated secretory phenotype, whereas PDK4 suppression reduces DNA damage severity and restrains the senescence-associated secretory phenotype. In preclinical trials, PDK4 inhibition alleviates physical dysfunction and prevents age-associated frailty. Together, our study confirms the hypercatabolic nature of senescent cells and reveals a metabolic link between cellular senescence, lactate production, and possibly, age-related pathologies, including but not limited to cancer.

DOI: https://doi.org/10.1038/s42255-023-00912-w
Sci Rep. 2023 10 29. 13(1): 18549

Lipidome and metabolome analyses reveal metabolic alterations associated with MCF-7 apoptosis upon 4-hydroxytamoxifen treatment.

Kazuki Nishimoto, Nobuyuki Okahashi, Masaharu Maruyama, Yoshihiro Izumi, Kohta Nakatani, Yuki Ito, Junko Iida, Takeshi Bamba, Fumio Matsuda.

4-hydroxytamoxifen (OHT) is an anti-cancer drug that induces apoptosis in breast cancer cells. Although changes in lipid levels and mitochondrial respiration have been observed in OHT-treated cells, the overall mechanisms underlying these metabolic alterations are poorly understood. In this study, time-series metabolomics and lipidomics were used to analyze the changes in metabolic profiles induced by OHT treatment in the MCF-7 human breast cancer cell line. Lipidomic and metabolomic analyses revealed increases in ceramide, diacylglycerol and triacylglycerol, and decreases in citrate, respectively. Gene expression analyses revealed increased expression of ATP-dependent citrate lyase (ACLY) and subsequent fatty acid biosynthetic enzymes, suggesting that OHT-treated MCF-7 cells activate citrate-to-lipid metabolism. The significance of the observed metabolic changes was evaluated by co-treating MCF-7 cells with OHT and ACLY or a diacylglycerol O-acyltransferase 1 (DGAT1) inhibitor. Co-treatment ameliorated cell death and reduced mitochondrial membrane potential compared to that in OHT treatment alone. The inhibition of cell death by co-treatment with an ACLY inhibitor has been observed in other breast cancer cell lines. These results suggest that citrate-to-lipid metabolism is critical for OHT-induced cell death in breast cancer cell lines.

DOI: https://doi.org/10.1038/s41598-023-45764-2
Nat Commun. 2023 Oct 28. 14(1): 6885

The Lin28b/Wnt5a axis drives pancreas cancer through crosstalk between cancer associated fibroblasts and tumor epithelium.

Zhaoqi Shu, Minghe Fan, Bo Tu, Zhiheng Tang, Haojie Wang, Haimeng Li, Hengchao Li, Meng Yuan, Jingru Bai, Sihan Huo, Lina Wang, Wei-Guo Zhu, Wei Wang, Xiaoyun Liu, Shaokun Shu, Ying Zhao.

Bidirectional signal transduction between tumor epithelial cells and tumor microenvironment (TME) is important for tumor development. Here we show that Lin28b/let-7 pathway is indispensable for modulating the expression of Wnt5a in tumor epithelium, which could be secreted and then up-regulates Lin28b in cancer-associated fibroblasts (CAFs). Moreover, we demonstrate that Lin28b in CAFs promoted growth of PDAC by inducing cytokine PCSK9's production. Using an orthotopic mouse model of PDAC, we find that depletion of Lin28b in CAFs reduced tumor weight, highlighting the importance of Lin28b in PDAC stroma. Thus, our study shows that the Lin28b-Wnt5a axis plays a critical role in bidirectional crosstalk between pancreatic tumor epithelium and TME and results in a pro-‍tumorigenic contexture.

DOI: https://doi.org/10.1038/s41467-023-42508-8
J Clin Invest. 2023 Nov 01. pii: e174540. [Epub ahead of print]133(21):

GLUT3 regulates alternative macrophage signaling through a glucose transport-independent role.

Peng Zhang, Jason Miska, Amy B Heimberger.

Macrophages are key mediators of innate immunity whose functional state can be regulated by glucose transporters. Although abundantly expressed in macrophages, the specific function of GLUT3, an isoform of facilitative glucose transporters, has not been clearly established. In this issue of the JCI, Dong-Min Yu and colleagues identify an alternative role for GLUT3 in promoting M2 macrophage polarization. The authors demonstrated that GLUT3 was upregulated upon M2 stimulation and was required for efficient alternative macrophage polarization and function. They further showed that GLUT3-induced M2 polarization was independent of glucose transport and functioned through Ras-mediated regulation of IL-4R endocytosis and IL-4/STAT6 activation. These findings may guide the development of macrophage-targeted treatments.

DOI: https://doi.org/10.1172/JCI174540
PLoS One. 2023 ;18(11): e0286660

Real-time resolution studies of the regulation of pyruvate-dependent lactate metabolism by hexokinases in single cells.

Scott John, Guillaume Calmettes, Shili Xu, Bernard Ribalet.

Lactate is a mitochondrial substrate for many tissues including neuron, muscle, skeletal and cardiac, as well as many cancer cells, however little is known about the processes that regulate its utilization in mitochondria. Based on the close association of Hexokinases (HK) with mitochondria, and the known cardio-protective role of HK in cardiac muscle, we have investigated the regulation of lactate and pyruvate metabolism by hexokinases (HKs), utilizing wild-type HEK293 cells and HEK293 cells in which the endogenous HKI and/or HKII have been knocked down to enable overexpression of wild type and mutant HKs. To assess the real-time changes in intracellular lactate levels the cells were transfected with a lactate specific FRET probe. In the HKI/HKII double knockdown cells, addition of extracellular pyruvate caused a large and sustained decrease in lactate. This decrease was rapidly reversed upon inhibition of the malate aspartate shuttle by aminooxyacetate, or inhibition of mitochondrial oxidative respiration by NaCN. These results suggest that in the absence of HKs, pyruvate-dependent activation of the TCA cycle together with the malate aspartate shuttle facilitates lactate transformation into pyruvate and its utilization by mitochondria. With replacement by overexpression of HKI or HKII the cellular response to pyruvate and NaCN was modified. With either hexokinase present, both the decrease in lactate due to the addition of pyruvate and the increase following addition of NaCN were either transient or suppressed altogether. Blockage of the pentose phosphate pathway with the inhibitor 6-aminonicotinamide (6-AN), abolished the effects of HK replacement. These results suggest that blocking of the malate aspartate shuttle by HK may involve activation of the pentose phosphate pathway and increased NADPH production.

DOI: https://doi.org/10.1371/journal.pone.0286660
Nat Commun. 2023 10 28. 14(1): 6872

A tuft cell - ILC2 signaling circuit provides therapeutic targets to inhibit gastric metaplasia and tumor development.

Ryan N O'Keefe, Annalisa L E Carli, David Baloyan, David Chisanga, Wei Shi, Shoukat Afshar-Sterle, Moritz F Eissmann, Ashleigh R Poh, Bhupinder Pal, Cyril Seillet, Richard M Locksley, Matthias Ernst, Michael Buchert.

Although gastric cancer is a leading cause of cancer-related deaths, systemic treatment strategies remain scarce. Here, we report the pro-tumorigenic properties of the crosstalk between intestinal tuft cells and type 2 innate lymphoid cells (ILC2) that is evolutionarily optimized for epithelial remodeling in response to helminth infection. We demonstrate that tuft cell-derived interleukin 25 (IL25) drives ILC2 activation, inducing the release of IL13 and promoting epithelial tuft cell hyperplasia. While the resulting tuft cell - ILC2 feed-forward circuit promotes gastric metaplasia and tumor formation, genetic depletion of tuft cells or ILC2s, or therapeutic targeting of IL13 or IL25 alleviates these pathologies in mice. In gastric cancer patients, tuft cell and ILC2 gene signatures predict worsening survival in intestinal-type gastric cancer where ~40% of the corresponding cancers show enriched co-existence of tuft cells and ILC2s. Our findings suggest a role for ILC2 and tuft cells, along with their associated cytokine IL13 and IL25 as gatekeepers and enablers of metaplastic transformation and gastric tumorigenesis, thereby providing an opportunity to therapeutically inhibit early-stage gastric cancer through repurposing antibody-mediated therapies.

DOI: https://doi.org/10.1038/s41467-023-42215-4
Br J Pharmacol. 2023 Oct 31.

Nitric oxide and thiols: Chemical biology, signaling paradigms, and vascular therapeutic potential.

Matthew R Dent, Anthony W DeMartino.

Nitric oxide (• NO) interactions with biological thiols play crucial, but incompletely determined roles in vascular signaling and other biological processes. Here, we highlight two recently proposed signaling paradigms: (1) the formation of a vasodilating labile nitrosyl ferrous heme (NO-ferroheme) facilitated by thiols via thiyl radical generation, and (2) polysulfides/persulfides and their interaction with • NO. We also describe the specific (bio)chemical routes in which • NO and thiols react to form S-nitrosothiols, a broad class of small molecules and protein post-translational modifications that can influence protein function through catalytic site or allosteric structural changes. S-nitrosothiol formation depends upon cellular conditions, but critically, an appropriate oxidant for either the thiol (yielding a thiyl radical) or • NO (yielding a nitrosonium (NO+ )-donating species) is required. We examine the roles of these collective • NO/thiol species in vascular signaling and their cardiovascular therapeutic potential.

DOI: https://doi.org/10.1111/bph.16274
Cancer Res. 2023 Oct 31.

Metabolomic rewiring promotes endocrine therapy resistance in breast cancer.

Songyeon Ahn, Jun Hyoung Park, Sandra L Grimm, Danthasinghe Waduge Badrajee Piyarathna, Tagari Samanta, Vasanta Putluri, Dereck Mezquita, Suzanne A W Fuqua, Nagireddy Putluri, Cristian Coarfa, Benny Abraham Kaipparettu.

Approximately one-third of endocrine-treated women with estrogen receptor-alpha positive (ER+) breast cancers (BC) are at risk of recurrence due to intrinsic or acquired resistance. Thus, it is vital to understand the mechanisms underlying endocrine therapy resistance in ER+ BC to improve patient treatment. Mitochondrial fatty acid β-oxidation (FAO) has been shown to be a major metabolic pathway in triple-negative BC (TNBC) that can activate Src signaling. Here, we found metabolic reprogramming that increases FAO in ER+ BC as a mechanism of resistance to endocrine therapy. A metabolically relevant, integrated gene signature was derived from transcriptomic, metabolomic, and lipidomic analyses in TNBC cells following inhibition of the FAO rate-limiting enzyme carnitine palmitoyl transferase 1 (CPT1), and this TNBC-derived signature was significantly associated with endocrine resistance in ER+ BC patients. Molecular, genetic, and metabolomic experiments identified activation of AMPK-FAO-oxidative phosphorylation (OXPHOS) signaling in endocrine-resistant ER+ BC. CPT1 knockdown or treatment with FAO inhibitors in vitro and in vivo significantly enhanced the response of ER+ BC cells to endocrine therapy. Consistent with the previous findings in TNBC, endocrine therapy-induced FAO activated the Src pathway in ER+ BC. Src inhibitors suppressed the growth of endocrine-resistant tumors, and the efficacy could be further enhanced by metabolic priming with CPT1 inhibition. Collectively, this study developed and applied a TNBC-derived signature to reveal that metabolic reprogramming to FAO activates the Src pathway to drive endocrine resistance in ER+ BC.

DOI: https://doi.org/10.1158/0008-5472.CAN-23-0184
J Biol Chem. 2023 Oct 26. pii: S0021-9258(23)02427-4. [Epub ahead of print] 105399

Mitochondrial hydrogen peroxide production by pyruvate dehydrogenase (PDH) and α-ketoglutarate dehydrogenase (KGDH) in oxidative eustress and oxidative distress.

Olivia Chalifoux, Ben Faerman, Ryan J Mailloux.

Pyruvate dehydrogenase (PDH) and α-ketoglutarate dehydrogenase (KGDH) are vital entry points for monosaccharides and amino acids into the Krebs cycle and thus integral for mitochondrial bioenergetics. Both complexes produce mitochondrial hydrogen peroxide (mH2O2) and are deactivated by electrophiles. Here, we provide an update on the role of PDH and KGDH in mitochondrial redox balance and their function in facilitating metabolic reprogramming for the propagation of oxidative eustress signals in hepatocytes and how defects in these pathways can cause liver diseases. PDH and KGDH are known to account for ∼45% of the total mH2O2 formed by mitochondria and display rates of production several-fold higher than the canonical source complex I. This mH2O2 can also be formed by reverse electron transfer (RET) in vivo, which has been linked to metabolic dysfunctions that occur in pathogenesis. However, the controlled emission of mH2O2 from PDH and KGDH has been proposed to be fundamental for oxidative eustress signal propagation in several cellular contexts. Modification of PDH and KGDH with protein S-glutathionylation (PSSG) and S-nitrosylation (PSNO) adducts serves as a feedback inhibitor for mH2O2 production in response to glutathione (GSH) pool oxidation. PSSG and PSNO adduct formation also reprogram the Krebs cycle to generate metabolites vital for interorganelle and intercellular signaling. Defects in the redox modification of PDH and KGDH cause the over generation of mH2O2, resulting in oxidative distress and metabolic dysfunction-associated fatty liver disease (MAFLD). In aggregate, PDH and KGDH are essential platforms for emitting and receiving oxidative eustress signals.

DOI: https://doi.org/10.1016/j.jbc.2023.105399
Nat Rev Cancer. 2023 Oct 31.

Metabolic pathway analysis using stable isotopes in patients with cancer.

Caroline R Bartman, Brandon Faubert, Joshua D Rabinowitz, Ralph J DeBerardinis.

Metabolic reprogramming is central to malignant transformation and cancer cell growth. How tumours use nutrients and the relative rates of reprogrammed pathways are areas of intense investigation. Tumour metabolism is determined by a complex and incompletely defined combination of factors intrinsic and extrinsic to cancer cells. This complexity increases the value of assessing cancer metabolism in disease-relevant microenvironments, including in patients with cancer. Stable-isotope tracing is an informative, versatile method for probing tumour metabolism in vivo. It has been used extensively in preclinical models of cancer and, with increasing frequency, in patients with cancer. In this Review, we describe approaches for using in vivo isotope tracing to define fuel preferences and pathway engagement in tumours, along with some of the principles that have emerged from this work. Stable-isotope infusions reported so far have revealed that in humans, tumours use a diverse set of nutrients to supply central metabolic pathways, including the tricarboxylic acid cycle and amino acid synthesis. Emerging data suggest that some activities detected by stable-isotope tracing correlate with poor clinical outcomes and may drive cancer progression. We also discuss current challenges in isotope tracing, including comparisons of in vivo and in vitro models, and opportunities for future discovery in tumour metabolism.

DOI: https://doi.org/10.1038/s41568-023-00632-z
Cell Rep. 2023 Nov 01. pii: S2211-1247(23)01226-3. [Epub ahead of print]42(11): 113214

LPGAT1 controls MEGDEL syndrome by coupling phosphatidylglycerol remodeling with mitochondrial transport.

Haoran Sun, Jun Zhang, Qianqian Ye, Ting Jiang, Xueling Liu, Xiaoyang Zhang, Fanyu Zeng, Jie Li, Yue Zheng, Xianlin Han, Chuan Su, Yuguang Shi.

  Phosphatidylglycerol (PG) is a mitochondrial phospholipid required for mitochondrial cristae structure and cardiolipin synthesis. PG must be remodeled to its mature form at the endoplasmic reticulum (ER) after mitochondrial biosynthesis to achieve its biological functions. Defective PG remodeling causes MEGDEL (non-alcohol fatty liver disease and 3-methylglutaconic aciduria with deafness, encephalopathy, and Leigh-like) syndrome through poorly defined mechanisms. Here, we identify LPGAT1, an acyltransferase that catalyzes PG remodeling, as a candidate gene for MEGDEL syndrome. We show that PG remodeling by LPGAT1 at the ER is closely coordinated with mitochondrial transport through interaction with the prohibitin/TIMM14 mitochondrial import motor. Accordingly, ablation of LPGAT1 or TIMM14 not only causes aberrant fatty acyl compositions but also ER retention of newly remodeled PG, leading to profound loss in mitochondrial crista structure and respiration. Consequently, genetic deletion of the LPGAT1 in mice leads to cardinal features of MEGDEL syndrome, including 3-methylglutaconic aciduria, deafness, dilated cardiomyopathy, and premature death, which are highly reminiscent of those caused by TIMM14 mutations in humans.

Keywords:  CP: Cell biology; LPGAT1; MEGDEL syndrome; mitochondrial dysfunction; phosphatidylglycerol; prohibitin/TIM complex

DOI:  https://doi.org/10.1016/j.celrep.2023.113214
Cell Metab. 2023 Oct 26. pii: S1550-4131(23)00372-8. [Epub ahead of print]

Hyperinsulinemia acts via acinar insulin receptors to initiate pancreatic cancer by increasing digestive enzyme production and inflammation.

Anni M Y Zhang, Yi Han Xia, Jeffrey S H Lin, Ken H Chu, Wei Chuan K Wang, Titine J J Ruiter, Jenny C C Yang, Nan Chen, Justin Chhuor, Shilpa Patil, Haoning Howard Cen, Elizabeth J Rideout, Vincent R Richard, David F Schaeffer, Rene P Zahedi, Christoph H Borchers, James D Johnson, Janel L Kopp.

  The rising pancreatic cancer incidence due to obesity and type 2 diabetes is closely tied to hyperinsulinemia, an independent cancer risk factor. Previous studies demonstrated reducing insulin production suppressed pancreatic intraepithelial neoplasia (PanIN) pre-cancerous lesions in Kras-mutant mice. However, the pathophysiological and molecular mechanisms remained unknown, and in particular it was unclear whether hyperinsulinemia affected PanIN precursor cells directly or indirectly. Here, we demonstrate that insulin receptors (Insr) in KrasG12D-expressing pancreatic acinar cells are dispensable for glucose homeostasis but necessary for hyperinsulinemia-driven PanIN formation in the context of diet-induced hyperinsulinemia and obesity. Mechanistically, this was attributed to amplified digestive enzyme protein translation, triggering of local inflammation, and PanIN metaplasia in vivo. In vitro, insulin dose-dependently increased acinar-to-ductal metaplasia formation in a trypsin- and Insr-dependent manner. Collectively, our data shed light on the mechanisms connecting obesity-driven hyperinsulinemia and pancreatic cancer development.

Keywords:  Kras; PanIN; acinar cells; hyperinsulinemia; inflammation; insulin receptor; insulin resistance; obesity; pancreatic cancer; pancreatic ductal adenocarcinoma

DOI:  https://doi.org/10.1016/j.cmet.2023.10.003
JCI Insight. 2023 Oct 31. pii: e164968. [Epub ahead of print]

Signaling metabolite succinylacetone activates HIF-1α and promotes angiogenesis in GSTZ1-deficient hepatocellular carcinoma.

Huating Luo, Qiujie Wang, Fan Yang, Rui Liu, Qingzhu Gao, Bin Cheng, Xue Lin, Luyi Huang, Chang Chen, Jin Xiang, Kai Wang, Bo Qin, Ni Tang.

  Aberrant angiogenesis in hepatocellular carcinoma (HCC) is associated with tumor growth, progression, and local or distant metastasis. Hypoxia-inducible factor 1α (HIF-1α) is a transcription factor that plays a major role in regulating angiogenesis during adaptation of tumor cells to nutrient-deprived microenvironment. Genetic defects in Krebs cycle enzymes, such as succinate dehydrogenase and fumarate hydratase, result in elevation of oncometabolites succinate and fumarate, thereby increasing HIF-1α stability and activating the HIF-1α signaling pathway. However, whether other metabolites regulate HIF-1α stability remains unclear. Here, we reported that the enzyme in phenylalanine/tyrosine catabolism glutathione S-transferase zeta 1 (GSTZ1) deficiency led to accumulation of succinylacetone, which was structurally similar to α-ketoglutarate. Succinylacetone competed with α-ketoglutarate for PHD2 binding and inhibited PHD2 activity, preventing hydroxylation of HIF-1α, thus resulting in its stabilization and consequent expression of vascular endothelial growth factor (VEGF). Our findings suggest that GSTZ1 may serve as an important tumor suppressor owing to its ability to inhibit the HIF-1α/VEGFA axis in HCC. Moreover, we explored the therapeutic potential of HIF-1α inhibitor combined with anti-PD-L1 therapy to effectively prevent HCC angiogenesis and tumorigenesis in Gstz1-knockout mice, suggesting a potentially actionable strategy for HCC treatment.

Keywords:  Liver cancer; Oncology

DOI:  https://doi.org/10.1172/jci.insight.164968
Exp Mol Med. 2023 Nov 02.

Caveolin-1 mediates the utilization of extracellular proteins for survival in refractory gastric cancer.

Nahee Hwang, Bo Kyung Yoon, Kyu-Hye Chun, Hyeonhui Kim, Yoseob Lee, Jae-Won Kim, Hyeonuk Jeon, Tae-Hyun Kim, Mi-Young Kim, Sungsoon Fang, Jae-Ho Cheong, Jae-Woo Kim.

Despite advances in cancer therapy, the clinical outcome of patients with gastric cancer remains poor, largely due to tumor heterogeneity. Thus, finding a hidden vulnerability of clinically refractory subtypes of gastric cancer is crucial. Here, we report that chemoresistant gastric cancer cells rely heavily on endocytosis, facilitated by caveolin-1, for survival. caveolin-1 was highly upregulated in the most malignant stem-like/EMT/mesenchymal (SEM)-type gastric cancer cells, allowing caveolin-1-mediated endocytosis and utilization of extracellular proteins via lysosomal degradation. Downregulation of caveolin-1 alone was sufficient to induce cell death in SEM-type gastric cancer cells, emphasizing its importance as a survival mechanism. Consistently, chloroquine, a lysosomal inhibitor, successfully blocked caveolin-1-mediated endocytosis, leading to the marked suppression of tumor growth in chemorefractory gastric cancer cells in vitro, including patient-derived organoids, and in vivo. Together, our findings suggest that caveolin-1-mediated endocytosis is a key metabolic pathway for gastric cancer survival and a potential therapeutic target.

DOI: https://doi.org/10.1038/s12276-023-01109-7
Cancer Res. 2023 11 01. 83(21): 3493-3494

Molecular Mechanism of Fasting-Mimicking Diet in Inhibiting Colorectal Cancer Progression: Implications for Immune Therapy and Metabolic Regulation.

Clancy O Bush, Rachel J Perry.

Recently, fasting-mimicking diet and caloric restriction have been shown to improve antitumor immunity. In this issue of Cancer Research, Zhong and colleagues provide insights into the molecular mechanism of fasting-mimicking diet-mediated metabolic reprogramming in colorectal cancer progression. The authors performed comprehensive mechanistic experiments in mouse models to show that fasting-mimicking diet prevents colorectal cancer progression by lowering intratumoral IgA+ B cells by accelerating fatty acid oxidation to inhibit B-cell IgA class switching. In addition, they found that fatty acid oxidation-dependent acetylation prevents IgA class switching and that IgA+ B cells interfere with the anticancer effects of fasting-mimicking diet in colorectal cancer. Overall, their study establishes that fasting-mimicking diet has the potential to activate anticancer immunity and to induce tumor regression in colorectal cancer. See related article by Zhong et al., p. 3529.

DOI: https://doi.org/10.1158/0008-5472.CAN-23-2257
Nat Commun. 2023 Nov 01. 14(1): 6966

Cancer-associated fibroblasts actively compress cancer cells and modulate mechanotransduction.

Jorge Barbazan, Carlos Pérez-González, Manuel Gómez-González, Mathieu Dedenon, Sophie Richon, Ernest Latorre, Marco Serra, Pascale Mariani, Stéphanie Descroix, Pierre Sens, Xavier Trepat, Danijela Matic Vignjevic.

During tumor progression, cancer-associated fibroblasts (CAFs) accumulate in tumors and produce an excessive extracellular matrix (ECM), forming a capsule that enwraps cancer cells. This capsule acts as a barrier that restricts tumor growth leading to the buildup of intratumoral pressure. Combining genetic and physical manipulations in vivo with microfabrication and force measurements in vitro, we found that the CAFs capsule is not a passive barrier but instead actively compresses cancer cells using actomyosin contractility. Abrogation of CAFs contractility in vivo leads to the dissipation of compressive forces and impairment of capsule formation. By mapping CAF force patterns in 3D, we show that compression is a CAF-intrinsic property independent of cancer cell growth. Supracellular coordination of CAFs is achieved through fibronectin cables that serve as scaffolds allowing force transmission. Cancer cells mechanosense CAF compression, resulting in an altered localization of the transcriptional regulator YAP and a decrease in proliferation. Our study unveils that the contractile capsule actively compresses cancer cells, modulates their mechanical signaling, and reorganizes tumor morphology.

DOI: https://doi.org/10.1038/s41467-023-42382-4
Elife. 2023 Oct 30. pii: RP87419. [Epub ahead of print]12

Hepatic conversion of acetyl-CoA to acetate plays crucial roles in energy stress.

Jinyang Wang, Yaxin Wen, Wentao Zhao, Yan Zhang, Furong Lin, Cong Ouyang, Huihui Wang, Lizheng Yao, Huanhuan Ma, Yue Zhuo, Huiying Huang, Xiulin Shi, Liubin Feng, Donghai Lin, Bin Jiang, Qinxi Li.

  Accumulating evidence indicates that acetate is increased under energy stress conditions such as those that occur in diabetes mellitus and prolonged starvation. However, how and where acetate is produced and the nature of its biological significance are largely unknown. We observed overproduction of acetate to concentrations comparable to those of ketone bodies in patients and mice with diabetes or starvation. Mechanistically, ACOT12 and ACOT8 are dramatically upregulated in the liver to convert free fatty acid-derived acetyl-CoA to acetate and CoA. This conversion not only provides a large amount of acetate, which preferentially fuels the brain rather than muscle, but also recycles CoA, which is required for sustained fatty acid oxidation and ketogenesis. We suggest that acetate is an emerging novel 'ketone body' that may be used as a parameter to evaluate the progression of energy stress.

Keywords:  ACOT12; ACOT8; acetate; biochemistry; cell biology; chemical biology; diabetes mellitus; human; mouse

DOI:  https://doi.org/10.7554/eLife.87419
Exp Hematol. 2023 Oct 26. pii: S0301-472X(23)01739-3. [Epub ahead of print]

Metabolic regulation in erythroid differentiation by systemic ketogenesis in fasted mice.

Wenjuan Ma, Yuichiro Arima, Terumasa Umemoto, Tomomasa Yokomizo, Yuqing Xu, Kenichi Miharada, Yosuke Tanaka, Toshio Suda.

Erythroid terminal differentiation and maturation depends on enormous energy supply. During periods of fasting, ketone bodies from the liver are transported into circulation and utilized as crucial fuel for peripheral tissues. However, effects of fasting or ketogenesis on erythroid behavior remain unknown. Here, we generated a mouse model with insufficient ketogenesis by conditionally knocking out the gene encoding the hepatocyte-specific ketogenic enzyme hydroxymethylglutary-CoA synthase 2 (Hmgcs2 KO). Intriguingly, erythroid maturation was enhanced with boosted fatty acid synthesis in bone marrow of hepatic Hmgcs2 KO mouse under fasting condition, suggesting that systemic ketogenesis has a profound effect on erythropoiesis. Moreover, we observed significantly activated fatty acids synthesis and mevalonate pathway along with reduced histone acetylation in immature erythrocytes under less systemic ketogenesis condition. Our findings revealed a new insight to erythroid differentiation, in which metabolic homeostasis and histone acetylation mediated by ketone bodies are essential factors in adaptation towards nutrient deprivation and stressed erythropoiesis.

DOI: https://doi.org/10.1016/j.exphem.2023.10.003
Oncogene. 2023 Oct 31.

RCCD1 promotes breast carcinogenesis through regulating hypoxia-associated mitochondrial homeostasis.

Yani Peng, Xiaoping Liu, Xinhua Liu, Xiao Cheng, Lu Xia, Leyi Qin, Sudun Guan, Yue Wang, Xiaodi Wu, Jiajing Wu, Dong Yan, Jianying Liu, Yu Zhang, Luyang Sun, Jing Liang, Yongfeng Shang.

Regulator of chromosome condensation domain-containing protein 1 (RCCD1), previously reported as a partner of histone H3K36 demethylase KDM8 involved in chromosome segregation, has been identified as a potential driver for breast cancer in a recent transcriptome-wide association study. We report here that, unexpectedly, RCCD1 is also localized in mitochondria. We show that RCCD1 resides in the mitochondrial matrix, where it interacts with the mitochondrial contact site/cristae organizing system (MICOS) and mitochondrial DNA (mtDNA) to regulate mtDNA transcription, oxidative phosphorylation, and the production of reactive oxygen species. Interestingly, RCCD1 is upregulated under hypoxic conditions, leading to decreased generation of reactive oxygen species and alleviated apoptosis favoring cancer cell survival. We show that RCCD1 promotes breast cancer cell proliferation in vitro and accelerates breast tumor growth in vivo. Indeed, RCCD1 is overexpressed in breast carcinomas, and its level of expression is associated with aggressive breast cancer phenotypes and poor patient survival. Our study reveals an additional dimension of RCCD1 functionality in regulating mitochondrial homeostasis, whose dysregulation inflicts pathologic states such as breast cancer.

DOI: https://doi.org/10.1038/s41388-023-02877-2
Sci Immunol. 2023 Nov 03. 8(89): eadd4374

CSF1R-dependent macrophages in the salivary gland are essential for epithelial regeneration after radiation-induced injury.

John G McKendrick, Gareth-Rhys Jones, Sonia S Elder, Erin Watson, Wouter T'Jonck, Ella Mercer, Marlene S Magalhaes, Cecilia Rocchi, Lizi M Hegarty, Amanda L Johnson, Christoph Schneider, Burkhard Becher, Clare Pridans, Neil Mabbott, Zhaoyuan Liu, Florent Ginhoux, Marc Bajenoff, Rebecca Gentek, Calum C Bain, Elaine Emmerson.

The salivary glands often become damaged in individuals receiving radiotherapy for head and neck cancer, resulting in chronic dry mouth. This leads to detrimental effects on their health and quality of life, for which there is no regenerative therapy. Macrophages are the predominant immune cell in the salivary glands and are attractive therapeutic targets due to their unrivaled capacity to drive tissue repair. Yet, the nature and role of macrophages in salivary gland homeostasis and how they may contribute to tissue repair after injury are not well understood. Here, we show that at least two phenotypically and transcriptionally distinct CX3CR1+ macrophage populations are present in the adult salivary gland, which occupy anatomically distinct niches. CD11c+CD206-CD163- macrophages typically associate with gland epithelium, whereas CD11c-CD206+CD163+ macrophages associate with blood vessels and nerves. Using a suite of complementary fate mapping systems, we show that there are highly dynamic changes in the ontogeny and composition of salivary gland macrophages with age. Using an in vivo model of radiation-induced salivary gland injury combined with genetic or antibody-mediated depletion of macrophages, we demonstrate an essential role for macrophages in clearance of cells with DNA damage. Furthermore, we show that epithelial-associated macrophages are indispensable for effective tissue repair and gland function after radiation-induced injury, with their depletion resulting in reduced saliva production. Our data, therefore, provide a strong case for exploring the therapeutic potential of manipulating macrophages to promote tissue repair and thus minimize salivary gland dysfunction after radiotherapy.

DOI: https://doi.org/10.1126/sciimmunol.add4374
Sci Transl Med. 2023 Nov;15(720): eadg3049

Tumor-specific GPX4 degradation enhances ferroptosis-initiated antitumor immune response in mouse models of pancreatic cancer.

Jingbo Li, Jiao Liu, Zhuan Zhou, Runliu Wu, Xin Chen, Chunhua Yu, Brent Stockwell, Guido Kroemer, Rui Kang, Daolin Tang.

Lipid peroxidation-dependent ferroptosis has become an emerging strategy for tumor therapy. However, current strategies not only selectively induce ferroptosis in malignant cells but also trigger ferroptosis in immune cells simultaneously, which can compromise anti-tumor immunity. Here, we used In-Cell Western assays combined with an unbiased drug screening to identify the compound N6F11 as a ferroptosis inducer that triggered the degradation of glutathione peroxidase 4 (GPX4), a key ferroptosis repressor, specifically in cancer cells. N6F11 did not cause the degradation of GPX4 in immune cells, including dendritic, T, natural killer, and neutrophil cells. Mechanistically, N6F11 bound to the RING domain of E3 ubiquitin ligase tripartite motif containing 25 (TRIM25) in cancer cells to trigger TRIM25-mediated K48-linked ubiquitination of GPX4, resulting in its proteasomal degradation. Functionally, N6F11 treatment caused ferroptotic cancer cell death that initiated HMGB1-dependent antitumor immunity mediated by CD8+ T cells. N6F11 also sensitized immune checkpoint blockade that targeted CD274/PD-L1 in advanced cancer models, including genetically engineered mouse models of pancreatic cancer driven by KRAS and TP53 mutations. These findings may establish a safe and efficient strategy to boost ferroptosis-driven antitumor immunity.

DOI: https://doi.org/10.1126/scitranslmed.adg3049