bims-mepmim Biomed News
on Metabolites in pathological microenvironments and immunometabolism
Issue of 2024–09–01
eightteen papers selected by
Erika Mariana Palmieri, NIH/NCI Laboratory of Cancer ImmunoMetabolism
  1. Mitochondrial membrane lipids in the regulation of bioenergetic flux.
  2. Serine and glycine physiology reversibly modulate retinal and peripheral nerve function.
  3. The glycolytic metabolite methylglyoxal covalently inactivates the NLRP3 inflammasome.
  4. An economic demand-based framework for prioritization strategies in response to transient amino acid limitations.
  5. Glucagon promotes increased hepatic mitochondrial oxidation and pyruvate carboxylase flux in humans with fatty liver disease.
  6. Immune suppression by human thymus-derived effector Tregs relies on glucose/lactate-fueled fatty acid synthesis.
  7. Lipid synthesis, triggered by PPARγ T166 dephosphorylation, sustains reparative function of macrophages during tissue repair.
  8. A cell state-specific metabolic vulnerability to GPX4-dependent ferroptosis in glioblastoma.
  9. Infection-induced peripheral mitochondria fission drives ER encapsulations and inter-mitochondria contacts that rescue bioenergetics.
  10. Efficient megakaryopoiesis and platelet production require phospholipid remodeling and PUFA uptake through CD36.
  11. Stearoyl-CoA desaturase inhibition is toxic to acute myeloid leukemia displaying high levels of the de novo fatty acid biosynthesis and desaturation.
  12. A nutrigeroscience approach: Dietary macronutrients and cellular senescence.
  13. Drp1 depletion protects against ferroptotic cell death by preserving mitochondrial integrity and redox homeostasis.
  14. The unique catalytic properties of PSAT1 mediate metabolic adaptation to glutamine blockade.
  15. Metabolite-based inter-kingdom communication controls intestinal tissue recovery following chemotherapeutic injury.
  16. Lipid transfer from tumour-associated macrophages supports glioblastoma.
  17. Activation and antitumor immunity of CD8+ T cells are supported by the glucose transporter GLUT10 and disrupted by lactic acid.
  18. Lactate helps cancer cells resist chemotherapy.
  1. Cell Metab. 2024 Aug 13. pii: S1550-4131(24)00326-7. [Epub ahead of print]
    Mitochondrial membrane lipids in the regulation of bioenergetic flux.
    Stephen Thomas Decker, Katsuhiko Funai.
      Oxidative phosphorylation (OXPHOS) occurs through and across the inner mitochondrial membrane (IMM). Mitochondrial membranes contain a distinct lipid composition, aided by lipid biosynthetic machinery localized in the IMM and class-specific lipid transporters that limit lipid traffic in and out of mitochondria. This unique lipid composition appears to be essential for functions of mitochondria, particularly OXPHOS, by its effects on direct lipid-to-protein interactions, membrane properties, and cristae ultrastructure. This review highlights the biological significance of mitochondrial lipids, with a particular spotlight on the role of lipids in mitochondrial bioenergetics. We describe pathways for the biosynthesis of mitochondrial lipids and provide evidence for their roles in physiology, their implications in human disease, and the mechanisms by which they regulate mitochondrial bioenergetics.
    Keywords:  bioenergetics; mitochondria; phospholipids
    DOI:  https://doi.org/10.1016/j.cmet.2024.07.024
  2. Cell Metab. 2024 Aug 21. pii: S1550-4131(24)00323-1. [Epub ahead of print]
    Serine and glycine physiology reversibly modulate retinal and peripheral nerve function.
    Esther W Lim, Regis J Fallon, Caleb Bates, Yoichiro Ideguchi, Takayuki Nagasaki, Michal K Handzlik, Emeline Joulia, Roberto Bonelli, Courtney R Green, Brendan R E Ansell, Maki Kitano, Ilham Polis, Amanda J Roberts, Furuya Shigeki, Rando Allikmets, Martina Wallace, Martin Friedlander, Christian M Metallo, Marin L Gantner.
      Metabolic homeostasis is maintained by redundant pathways to ensure adequate nutrient supply during fasting and other stresses. These pathways are regulated locally in tissues and systemically via the liver, kidney, and circulation. Here, we characterize how serine, glycine, and one-carbon (SGOC) metabolism fluxes across the eye, liver, and kidney sustain retinal amino acid levels and function. Individuals with macular telangiectasia (MacTel), an age-related retinal disease with reduced circulating serine and glycine, carrying deleterious alleles in SGOC metabolic enzymes exhibit an exaggerated reduction in circulating serine. A Phgdh+/- mouse model of this haploinsufficiency experiences accelerated retinal defects upon dietary serine/glycine restriction, highlighting how otherwise silent haploinsufficiencies can impact retinal health. We demonstrate that serine-associated retinopathy and peripheral neuropathy are reversible, as both are restored in mice upon serine supplementation. These data provide molecular insights into the genetic and metabolic drivers of neuro-retinal dysfunction while highlighting therapeutic opportunities to ameliorate this pathogenesis.
    Keywords:  MacTel; PHGDH; glycine; glycine cleavage; one-carbon metabolism; retina metabolism; serine; serine supplementation; sphingolipids; stable-isotope tracing
    DOI:  https://doi.org/10.1016/j.cmet.2024.07.021
  3. Cell Rep. 2024 Aug 27. pii: S2211-1247(24)01039-8. [Epub ahead of print]43(9): 114688
    The glycolytic metabolite methylglyoxal covalently inactivates the NLRP3 inflammasome.
    Caroline Stanton, Chavin Buasakdi, Jie Sun, Ian Levitan, Prerona Bora, Sergei Kutseikin, R Luke Wiseman, Michael J Bollong.
      The NLRP3 inflammasome promotes inflammation in disease, yet the full repertoire of mechanisms regulating its activity is not well delineated. Among established regulatory mechanisms, covalent modification of NLRP3 has emerged as a common route for the pharmacological inactivation of this protein. Here, we show that inhibition of the glycolytic enzyme phosphoglycerate kinase 1 (PGK1) results in the accumulation of methylglyoxal, a reactive metabolite whose increased levels decrease NLRP3 assembly and inflammatory signaling in cells. We find that methylglyoxal inactivates NLRP3 via a non-enzymatic, covalent-crosslinking-based mechanism, promoting inter- and intraprotein MICA (methyl imidazole crosslink between cysteine and arginine) posttranslational linkages within NLRP3. This work establishes NLRP3 as capable of sensing a host of electrophilic chemicals, both exogenous small molecules and endogenous reactive metabolites, and suggests a mechanism by which glycolytic flux can moderate the activation status of a central inflammatory signaling pathway.
    Keywords:  CP: Immunology; CP: Metabolism; MICA modification; NLRP3; PGK1; covalent; glycolysis; inflammasome; inflammation; methylglyoxal
    DOI:  https://doi.org/10.1016/j.celrep.2024.114688
  4. Nat Commun. 2024 Aug 23. 15(1): 7254
    An economic demand-based framework for prioritization strategies in response to transient amino acid limitations.
    Ritu Gupta, Swagata Adhikary, Nidhi Dalpatraj, Sunil Laxman.
      Cells contain disparate amounts of distinct amino acids, each of which has different metabolic and chemical origins, but the supply cost vs demand requirements of each is unclear. Here, using yeast we quantify the restoration-responses after disrupting amino acid supply, and uncover a hierarchically prioritized restoration strategy for distinct amino acids. We comprehensively calculate individual amino acid biosynthetic supply costs, quantify total demand for an amino acid, and estimate cumulative supply/demand requirements for each amino acid. Through this, we discover that the restoration priority is driven by the gross demand for an amino acid, which is itself coupled to low supply costs for that amino acid. Demand from metabolic requirements dominate the demand-pulls for an amino acid, as exemplified by the largest restoration response upon disrupting arginine supply. Collectively, this demand-driven framework that drives the amino acid economy can identify novel amino acid responses, and help design metabolic engineering applications.
    DOI:  https://doi.org/10.1038/s41467-024-51769-w
  5. Cell Metab. 2024 Aug 21. pii: S1550-4131(24)00325-5. [Epub ahead of print]
    Glucagon promotes increased hepatic mitochondrial oxidation and pyruvate carboxylase flux in humans with fatty liver disease.
    Kitt Falk Petersen, Sylvie Dufour, Wajahat Z Mehal, Gerald I Shulman.
      We assessed in vivo rates of hepatic mitochondrial oxidation, gluconeogenesis, and β-hydroxybutyrate (β-OHB) turnover by positional isotopomer NMR tracer analysis (PINTA) in individuals with metabolic-dysfunction-associated steatotic liver (MASL) (fatty liver) and MASL disease (MASLD) (steatohepatitis) compared with BMI-matched control participants with no hepatic steatosis. Hepatic fat content was quantified by localized 1H magnetic resonance spectroscopy (MRS). We found that in vivo rates of hepatic mitochondrial oxidation were unaltered in the MASL and MASLD groups compared with the control group. A physiological increase in plasma glucagon concentrations increased in vivo rates of hepatic mitochondrial oxidation by 50%-75% in individuals with and without MASL and increased rates of glucose production by ∼50% in the MASL group, which could be attributed in part to an ∼30% increase in rates of mitochondrial pyruvate carboxylase flux. These results demonstrate that (1) rates of hepatic mitochondrial oxidation are not substantially altered in individuals with MASL and MASLD and (2) glucagon increases rates of hepatic mitochondrial oxidation.
    Keywords:  MASL; MASLD; NAFLD; NASH; citrate synthase flux; gluconeogenesis; hepatic mitochondrial oxidation; magnetic resonance spectroscopy; pyruvate carboxylase flux; β-hydroxybutyrate
    DOI:  https://doi.org/10.1016/j.cmet.2024.07.023
  6. Cell Rep. 2024 Aug 23. pii: S2211-1247(24)01032-5. [Epub ahead of print]43(9): 114681
    Immune suppression by human thymus-derived effector Tregs relies on glucose/lactate-fueled fatty acid synthesis.
    Sander de Kivit, Mark Mensink, Sarantos Kostidis, Rico J E Derks, Esther A Zaal, Marieke Heijink, Lotte J Verleng, Evert de Vries, Ellen Schrama, Niek Blomberg, Celia R Berkers, Martin Giera, Jannie Borst.
      Regulatory T cells (Tregs) suppress pro-inflammatory conventional T cell (Tconv) responses. As lipids impact cell signaling and function, we compare the lipid composition of CD4+ thymus-derived (t)Tregs and Tconvs. Lipidomics reveal constitutive enrichment of neutral lipids in Tconvs and phospholipids in tTregs. TNFR2-co-stimulated effector tTregs and Tconvs are both glycolytic, but only in tTregs are glycolysis and the tricarboxylic acid (TCA) cycle linked to a boost in fatty acid (FA) synthesis (FAS), supported by relevant gene expression. FA chains in tTregs are longer and more unsaturated than in Tconvs. In contrast to Tconvs, tTregs effectively use either lactate or glucose for FAS and rely on this process for proliferation. FASN and SCD1, enzymes responsible for FAS and FA desaturation, prove essential for the ability of tTregs to suppress Tconvs. These data illuminate how effector tTregs can thrive in inflamed or cancerous tissues with limiting glucose but abundant lactate levels.
    Keywords:  (regulatory) T cell; CP: Immunology; CP: Metabolism; costimulation; fatty acids; glycolysis; immune suppression; isotopologue tracing; lactate; lipidomics; mass spectrometry; metabolism
    DOI:  https://doi.org/10.1016/j.celrep.2024.114681
  7. Nat Commun. 2024 Aug 23. 15(1): 7269
    Lipid synthesis, triggered by PPARγ T166 dephosphorylation, sustains reparative function of macrophages during tissue repair.
    Shiman Zuo, Yuxin Wang, Hanjing Bao, Zehui Zhang, Nanfei Yang, Meng Jia, Qing Zhang, Ani Jian, Rong Ji, Lidan Zhang, Yan Lu, Yahong Huang, Pingping Shen.
      Macrophages may acquire a reparative phenotype that supports tissue repair and remodeling in response to tissue injury. However, the metabolic requirements underpinning this process are incompletely understood. Here, we show that posttranslational modification (PTM) of PPARγ regulates lipid synthesis in response to wound microenvironmental cues and that metabolic rewiring orchestrates function of reparative macrophages. In injured tissues, repair signaling leads to decreased macrophage PPARγ threonine 166 (T166) phosphorylation, which results in a partially active PPARγ transcriptional program comprised of increased binding activity to the regulator regions of lipid synthesis-associated genes, thereby increased lipogenesis. The accumulated lipids serve as signaling molecules, triggering STAT3-mediated growth factor expression, and supporting the synthesis of phospholipids for the expansion of the endoplasmic reticulum (ER), which is required for protein secretion. Genetic or pharmacological inhibition of PPARγ T166 phosphorylation promotes the reparative function of macrophages and facilitates tissue regeneration. In summary, our work identifies PPARγ T166-regulated lipid biosynthesis as an essential pathway for meeting the anabolic demands of the activation and function of macrophages and provides a rationale for potential therapeutic targeting of tissue repair.
    DOI:  https://doi.org/10.1038/s41467-024-51736-5
  8. EMBO J. 2024 Aug 27.
    A cell state-specific metabolic vulnerability to GPX4-dependent ferroptosis in glioblastoma.
    Matei A Banu, Athanassios Dovas, Michael G Argenziano, Wenting Zhao, Colin P Sperring, Henar Cuervo Grajal, Zhouzerui Liu, Dominique Mo Higgins, Misha Amini, Brianna Pereira, Ling F Ye, Aayushi Mahajan, Nelson Humala, Julia L Furnari, Pavan S Upadhyayula, Fereshteh Zandkarimi, Trang Tt Nguyen, Damian Teasley, Peter B Wu, Li Hai, Charles Karan, Tyrone Dowdy, Aida Razavilar, Markus D Siegelin, Jan Kitajewski, Mioara Larion, Jeffrey N Bruce, Brent R Stockwell, Peter A Sims, Peter Canoll.
      Glioma cells hijack developmental programs to control cell state. Here, we uncover a glioma cell state-specific metabolic liability that can be therapeutically targeted. To model cell conditions at brain tumor inception, we generated genetically engineered murine gliomas, with deletion of p53 alone (p53) or with constitutively active Notch signaling (N1IC), a pathway critical in controlling astrocyte differentiation during brain development. N1IC tumors harbored quiescent astrocyte-like transformed cell populations while p53 tumors were predominantly comprised of proliferating progenitor-like cell states. Further, N1IC transformed cells exhibited increased mitochondrial lipid peroxidation, high ROS production and depletion of reduced glutathione. This altered mitochondrial phenotype rendered the astrocyte-like, quiescent populations more sensitive to pharmacologic or genetic inhibition of the lipid hydroperoxidase GPX4 and induction of ferroptosis. Treatment of patient-derived early-passage cell lines and glioma slice cultures generated from surgical samples with a GPX4 inhibitor induced selective depletion of quiescent astrocyte-like glioma cell populations with similar metabolic profiles. Collectively, these findings reveal a specific therapeutic vulnerability to ferroptosis linked to mitochondrial redox imbalance in a subpopulation of quiescent astrocyte-like glioma cells resistant to standard forms of treatment.
    Keywords:  Astrocytic; Ferroptosis; Glioma; Mitochondrial-metabolism; Quiescent
    DOI:  https://doi.org/10.1038/s44318-024-00176-4
  9. Nat Commun. 2024 Aug 27. 15(1): 7352
    Infection-induced peripheral mitochondria fission drives ER encapsulations and inter-mitochondria contacts that rescue bioenergetics.
    William A Hofstadter, Katelyn C Cook, Elene Tsopurashvili, Robert Gebauer, Vojtěch Pražák, Emily A Machala, Ji Woo Park, Kay Grünewald, Emmanuelle R J Quemin, Ileana M Cristea.
      The dynamic regulation of mitochondria shape via fission and fusion is critical for cellular responses to stimuli. In homeostatic cells, two modes of mitochondrial fission, midzone and peripheral, provide a decision fork between either proliferation or clearance of mitochondria. However, the relationship between specific mitochondria shapes and functions remains unclear in many biological contexts. While commonly associated with decreased bioenergetics, fragmented mitochondria paradoxically exhibit elevated respiration in several disease states, including infection with the prevalent pathogen human cytomegalovirus (HCMV) and metastatic melanoma. Here, incorporating super-resolution microscopy with mass spectrometry and metabolic assays, we use HCMV infection to establish a molecular mechanism for maintaining respiration within a fragmented mitochondria population. We establish that HCMV induces fragmentation through peripheral mitochondrial fission coupled with suppression of mitochondria fusion. Unlike uninfected cells, the progeny of peripheral fission enter mitochondria-ER encapsulations (MENCs) where they are protected from degradation and bioenergetically stabilized during infection. MENCs also stabilize pro-viral inter-mitochondria contacts (IMCs), which electrochemically link mitochondria and promote respiration. Demonstrating a broader relevance, we show that the fragmented mitochondria within metastatic melanoma cells also form MENCs. Our findings establish a mechanism where mitochondria fragmentation can promote increased respiration, a feature relevant in the context of human diseases.
    DOI:  https://doi.org/10.1038/s41467-024-51680-4
  10. Nat Cardiovasc Res. 2023 Aug;2(8): 746-763
    Efficient megakaryopoiesis and platelet production require phospholipid remodeling and PUFA uptake through CD36.
    Maria N Barrachina, Gerard Pernes, Isabelle C Becker, Isabelle Allaeys, Thomas I Hirsch, Dafna J Groeneveld, Abdullah O Khan, Daniela Freire, Karen Guo, Estelle Carminita, Pooranee K Morgan, Thomas J C Collins, Natalie A Mellett, Zimu Wei, Ibrahim Almazni, Joseph E Italiano, James Luyendyk, Peter J Meikle, Mark Puder, Neil V Morgan, Eric Boilard, Andrew J Murphy, Kellie R Machlus.
      Lipids contribute to hematopoiesis and membrane properties and dynamics; however, little is known about the role of lipids in megakaryopoiesis. Here we show that megakaryocyte progenitors, megakaryocytes and platelets present a unique lipidome progressively enriched in polyunsaturated fatty acid (PUFA)-containing phospholipids. In vitro, inhibition of both exogenous fatty acid functionalization and uptake as well as de novo lipogenesis impaired megakaryocyte differentiation and proplatelet production. In vivo, mice on a high saturated fatty acid diet had significantly lower platelet counts, which was prevented by eating a PUFA-enriched diet. Fatty acid uptake was largely dependent on CD36, and its deletion in mice resulted in low platelets. Moreover, patients with a CD36 loss-of-function mutation exhibited thrombocytopenia and increased bleeding. Our results suggest that fatty acid uptake and regulation is essential for megakaryocyte maturation and platelet production and that changes in dietary fatty acids may be a viable target to modulate platelet counts.
    DOI:  https://doi.org/10.1038/s44161-023-00305-y
  11. Leukemia. 2024 Aug 26.
    Stearoyl-CoA desaturase inhibition is toxic to acute myeloid leukemia displaying high levels of the de novo fatty acid biosynthesis and desaturation.
    Vilma Dembitz, Hannah Lawson, Richard Burt, Sirisha Natani, Céline Philippe, Sophie C James, Samantha Atkinson, Jozef Durko, Lydia M Wang, Joana Campos, Aoife M S Magee, Keith Woodley, Michael J Austin, Ana Rio-Machin, Pedro Casado, Findlay Bewicke-Copley, Giovanny Rodriguez Blanco, Diego Pereira-Martins, Lieve Oudejans, Emeline Boet, Alex von Kriegsheim, Juerg Schwaller, Andrew J Finch, Bela Patel, Jean-Emmanuel Sarry, Jerome Tamburini, Jan Jacob Schuringa, Lori Hazlehurst, John A Copland Iii, Mariia Yuneva, Barrie Peck, Pedro Cutillas, Jude Fitzgibbon, Kevin Rouault-Pierre, Kamil Kranc, Paolo Gallipoli.
      Identification of specific and therapeutically actionable vulnerabilities, ideally present across multiple mutational backgrounds, is needed to improve acute myeloid leukemia (AML) patients' outcomes. We identify stearoyl-CoA desaturase (SCD), the key enzyme in fatty acid (FA) desaturation, as prognostic of patients' outcomes and, using the clinical-grade inhibitor SSI-4, show that SCD inhibition (SCDi) is a therapeutic vulnerability across multiple AML models in vitro and in vivo. Multiomic analysis demonstrates that SCDi causes lipotoxicity, which induces AML cell death via pleiotropic effects. Sensitivity to SCDi correlates with AML dependency on FA desaturation regardless of mutational profile and is modulated by FA biosynthesis activity. Finally, we show that lipotoxicity increases chemotherapy-induced DNA damage and standard chemotherapy further sensitizes AML cells to SCDi. Our work supports developing FA desaturase inhibitors in AML while stressing the importance of identifying predictive biomarkers of response and biologically validated combination therapies to realize their full therapeutic potential.
    DOI:  https://doi.org/10.1038/s41375-024-02390-9
  12. Cell Metab. 2024 Aug 15. pii: S1550-4131(24)00327-9. [Epub ahead of print]
    A nutrigeroscience approach: Dietary macronutrients and cellular senescence.
    Mariah F Calubag, Paul D Robbins, Dudley W Lamming.
      Cellular senescence, a process in which a cell exits the cell cycle in response to stressors, is one of the hallmarks of aging. Senescence and the senescence-associated secretory phenotype (SASP)-a heterogeneous set of secreted factors that disrupt tissue homeostasis and promote the accumulation of senescent cells-reprogram metabolism and can lead to metabolic dysfunction. Dietary interventions have long been studied as methods to combat age-associated metabolic dysfunction, promote health, and increase lifespan. A growing body of literature suggests that senescence is responsive to diet, both to calories and specific dietary macronutrients, and that the metabolic benefits of dietary interventions may arise in part through reducing senescence. Here, we review what is currently known about dietary macronutrients' effect on senescence and the SASP, the nutrient-responsive molecular mechanisms that may mediate these effects, and the potential for these findings to inform the development of a nutrigeroscience approach to healthy aging.
    Keywords:  branched-chain amino acids; cellular senescence; healthspan; macronutrients; nutrigeroscience; protein; senescence-associated secretory phenotype
    DOI:  https://doi.org/10.1016/j.cmet.2024.07.025
  13. Cell Death Dis. 2024 Aug 27. 15(8): 626
    Drp1 depletion protects against ferroptotic cell death by preserving mitochondrial integrity and redox homeostasis.
    Stephan Tang, Anneke Fuß, Zohreh Fattahi, Carsten Culmsee.
      Mitochondria are highly dynamic organelles which undergo constant fusion and fission as part of the mitochondrial quality control. In genetic diseases and age-related neurodegenerative disorders, altered mitochondrial fission-fusion dynamics have been linked to impaired mitochondrial quality control, disrupted organelle integrity and function, thereby promoting neural dysfunction and death. The key enzyme regulating mitochondrial fission is the GTPase Dynamin-related Protein 1 (Drp1), which is also considered as a key player in mitochondrial pathways of regulated cell death. In particular, increasing evidence suggests a role for impaired mitochondrial dynamics and integrity in ferroptosis, which is an iron-dependent oxidative cell death pathway with relevance in neurodegeneration. In this study, we demonstrate that CRISPR/Cas9-mediated genetic depletion of Drp1 exerted protective effects against oxidative cell death by ferroptosis through preserved mitochondrial integrity and maintained redox homeostasis. Knockout of Drp1 resulted in mitochondrial elongation, attenuated ferroptosis-mediated impairment of mitochondrial membrane potential, and stabilized iron trafficking and intracellular iron storage. In addition, Drp1 deficiency exerted metabolic effects, with reduced basal and maximal mitochondrial respiration and a metabolic shift towards glycolysis. These metabolic effects further alleviated the mitochondrial contribution to detrimental ROS production thereby significantly enhancing neural cell resilience against ferroptosis. Taken together, this study highlights the key role of Drp1 in mitochondrial pathways of ferroptosis and expose the regulator of mitochondrial dynamics as a potential therapeutic target in neurological diseases involving oxidative dysregulation.
    DOI:  https://doi.org/10.1038/s41419-024-07015-8
  14. Nat Metab. 2024 Aug;6(8): 1529-1548
    The unique catalytic properties of PSAT1 mediate metabolic adaptation to glutamine blockade.
    Yijian Qiu, Olivia T Stamatatos, Qingting Hu, Jed Ruiter Swain, Suzanne Russo, Ava Sann, Ana S H Costa, Sara Violante, David L Spector, Justin R Cross, Michael J Lukey.
      Cultured cancer cells frequently rely on the consumption of glutamine and its subsequent hydrolysis by glutaminase (GLS). However, this metabolic addiction can be lost in the tumour microenvironment, rendering GLS inhibitors ineffective in the clinic. Here we show that glutamine-addicted breast cancer cells adapt to chronic glutamine starvation, or GLS inhibition, via AMPK-mediated upregulation of the serine synthesis pathway (SSP). In this context, the key product of the SSP is not serine, but α-ketoglutarate (α-KG). Mechanistically, we find that phosphoserine aminotransferase 1 (PSAT1) has a unique capacity for sustained α-KG production when glutamate is depleted. Breast cancer cells with resistance to glutamine starvation or GLS inhibition are highly dependent on SSP-supplied α-KG. Accordingly, inhibition of the SSP prevents adaptation to glutamine blockade, resulting in a potent drug synergism that suppresses breast tumour growth. These findings highlight how metabolic redundancy can be context dependent, with the catalytic properties of different metabolic enzymes that act on the same substrate determining which pathways can support tumour growth in a particular nutrient environment. This, in turn, has practical consequences for therapies targeting cancer metabolism.
    DOI:  https://doi.org/10.1038/s42255-024-01104-w
  15. Cell Host Microbe. 2024 Aug 20. pii: S1931-3128(24)00285-3. [Epub ahead of print]
    Metabolite-based inter-kingdom communication controls intestinal tissue recovery following chemotherapeutic injury.
    Christopher J Anderson, Laura Boeckaerts, Pricilla Chin, Javier Burgoa Cardas, Wei Xie, Amanda Gonçalves, Gillian Blancke, Sam Benson, Sebastian Rogatti, Mariska S Simpson, Anna Davey, Sze Men Choi, Sandrien Desmet, Summer D Bushman, Geert Goeminne, Peter Vandenabeele, Mahesh S Desai, Lars Vereecke, Kodi S Ravichandran.
      Cytotoxic chemotherapies have devastating side effects, particularly within the gastrointestinal tract. Gastrointestinal toxicity includes the death and damage of the epithelium and an imbalance in the intestinal microbiota, otherwise known as dysbiosis. Whether dysbiosis is a direct contributor to tissue toxicity is a key area of focus. Here, from both mammalian and bacterial perspectives, we uncover an intestinal epithelial cell death-Enterobacteriaceae signaling axis that fuels dysbiosis. Specifically, our data demonstrate that chemotherapy-induced epithelial cell apoptosis and the purine-containing metabolites released from dying cells drive the inter-kingdom transcriptional re-wiring of the Enterobacteriaceae, including fundamental shifts in bacterial respiration and promotion of purine utilization-dependent expansion, which in turn delays the recovery of the intestinal tract. Inhibition of epithelial cell death or restriction of the Enterobacteriaceae to homeostatic levels reverses dysbiosis and improves intestinal recovery. These findings suggest that supportive therapies that maintain homeostatic levels of Enterobacteriaceae may be useful in resolving intestinal disease.
    Keywords:  Enterobacteriaceae; apoptosis; chemotherapy; dysbiosis; intestinal epithelium
    DOI:  https://doi.org/10.1016/j.chom.2024.07.026
  16. Nat Rev Immunol. 2024 Aug 23.
    Lipid transfer from tumour-associated macrophages supports glioblastoma.
    Kirsty Minton.
      
    DOI:  https://doi.org/10.1038/s41577-024-01086-6
  17. Sci Transl Med. 2024 Aug 28. 16(762): eadk7399
    Activation and antitumor immunity of CD8+ T cells are supported by the glucose transporter GLUT10 and disrupted by lactic acid.
    Ying Liu, Feng Wang, Dongxue Peng, Dan Zhang, Luping Liu, Jun Wei, Jian Yuan, Luyao Zhao, Huimin Jiang, Tingting Zhang, Yunxuan Li, Chenxi Zhao, Shuhua He, Jie Wu, Yechao Yan, Peitao Zhang, Chunyi Guo, Jiaming Zhang, Xia Li, Huan Gao, Ke Li.
      CD8+ T cell activation leads to the rapid proliferation and differentiation of effector T cells (Teffs), which mediate antitumor immunity. Although aerobic glycolysis is preferentially activated in CD8+ Teffs, the mechanisms that regulate CD8+ T cell glucose uptake in the low-glucose and acidic tumor microenvironment (TME) remain poorly understood. Here, we report that the abundance of the glucose transporter GLUT10 is increased during CD8+ T cell activation and antitumor immunity. Specifically, GLUT10 deficiency inhibited glucose uptake, glycolysis, and antitumor efficiency of tumor-infiltrating CD8+ T cells. Supplementation with glucose alone was insufficient to rescue the antitumor function and glucose uptake of CD8+ T cells in the TME. By analyzing tumor environmental metabolites, we found that high concentrations of lactic acid reduced the glucose uptake, activation, and antitumor effects of CD8+ T cells by directly binding to GLUT10's intracellular motif. Disrupting the interaction of lactic acid and GLUT10 by the mimic peptide PG10.3 facilitated CD8+ T cell glucose utilization, proliferation, and antitumor functions. The combination of PG10.3 and GLUT1 inhibition or anti-programmed cell death 1 antibody treatment showed synergistic antitumor effects. Together, our data indicate that GLUT10 is selectively required for glucose uptake of CD8+ T cells and identify that TME accumulated lactic acid inhibits CD8+ T cell effector function by directly binding to GLUT10 and reducing its glucose transport capacity. Last, our study suggests disrupting lactate-GLUT10 binding as a promising therapeutic strategy to enhance CD8+ T cell-mediated antitumor effects.
    DOI:  https://doi.org/10.1126/scitranslmed.adk7399
  18. Nature. 2024 Aug 23.
    Lactate helps cancer cells resist chemotherapy.
      
    Keywords:  Cancer; Metabolism
    DOI:  https://doi.org/10.1038/d41586-024-02731-9
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