bims-mepmim Biomed News
on Metabolites in pathological microenvironments and immunometabolism
Issue of 2022‒05‒15
forty-six papers selected by
Erika Mariana Palmieri
NIH/NCI Laboratory of Cancer ImmunoMetabolism
  1. Role of Amino Acid Transporter SNAT1/SLC38A1 in Human Melanoma.
  2. A pan-cancer metabolic atlas of the tumor microenvironment.
  3. The Role of Extracellular Vesicles in Metabolic Reprogramming of the Tumor Microenvironment.
  4. Glucose Starvation or Pyruvate Dehydrogenase Activation Induce a Broad, ERK5-Mediated, Metabolic Remodeling Leading to Fatty Acid Oxidation.
  5. Development of Cancer-on-a-chip Technology for the Study of Tumor Microenvironment and Metabolism.
  6. Targeting 2-oxoglutarate dehydrogenase for cancer treatment.
  7. Labile Heme and Heme Oxygenase-1 Maintain Tumor-Permissive Niche for Endometriosis-Associated Ovarian Cancer.
  8. Tumor-Associated Macrophages and Ovarian Cancer: Implications for Therapy.
  9. Targeting Myocardial Substrate Metabolism in the Failing Heart: Ready for Prime Time?
  10. d-2-Hydroxyglutarate is an anti-inflammatory immunometabolite that accumulates in macrophages after TLR4 activation.
  11. Space- and Time-Resolved Metabolomics of a High-Grade Serous Ovarian Cancer Mouse Model.
  12. Glucose-1-phosphate regulates orphan nuclear receptor NR4A1 and apoptosis.
  13. SCD1/FADS2 fatty acid desaturases equipoise lipid metabolic activity and redox-driven ferroptosis in ascites-derived ovarian cancer cells.
  14. Mechanistic basis for the allosteric activation of mitochondrial glutaminase C, a key driver of glutamine metabolism in cancer cells.
  15. Limiting Mitochondrial Magnesium Exacerbates Ketogenic Insufficiency and Alters Hepatic Lipid Metabolism.
  16. Novel Roles of FFAR4 in Macrophage Foam Cell Formation.
  17. Lipid Metabolism and Ferroptosis.
  18. Interleukin 21-induced Mitochondrial Dysfunction Drives Regulatory T Cell Inflammatory Response during Intestinal Inflammation.
  19. Comprehensive Analysis of Subtypes and Identification of Key lncRNAs Based on Glutamine Metabolism-Related Long Noncoding RNAs.
  20. Elucidating the role of NUDT19 in renal lipid metabolism.
  21. Editorial: Metabolite and Nutrient Transporters in Cancer-Cell Metabolism: Role in Cancer Progression and Metastasis.
  22. LDH-A-Modulation and the Variability of LDH Isoenzyme Profiles in Murine Gliomas: A Link with Metabolic and Growth Responses.
  23. Transcriptome and Mass-Spectrometry-Based Lipidome Reveal a Role of PRMT5 in Membrane Transport and Cholesterol Synthesis in White Adipocytes.
  24. Identification of a novel lipid metabolism-related gene signature within the tumour immune microenvironment for breast cancer.
  25. Lipogenesis mediated by OGR1 regulates metabolic adaptation to acid stress in cancer cells via autophagy.
  26. Inhibition of Anaplerosis Prevented Mitochondrial Dysfunction and Vascular Remodeling in Pulmonary Hypertension.
  27. Fatty acid binding protein 5 regulates lipogenesis and tumor growth in lung adenocarcinoma.
  28. How CAR T Cells Breathe.
  29. Glycerol's contribution to lactate production outside of a glucose intermediate in fasting humans.
  30. Phosphoglycerate Mutase 5 Expression Modulates Hepatocellular Steatosis.
  31. The short-chain fatty acid acetate modulates epithelial-to-mesenchymal transition.
  32. Isomeric lipid signatures reveal compartmentalized fatty acid metabolism in cancer.
  33. Role of adipose tissue macrophages in obesity-related disorders.
  34. Overcoming T cell dysfunction in acidic pH to enhance adoptive T cell transfer immunotherapy.
  35. LAT1-specific inhibitor ameliorates severe autoimmune arthritis in SKG mouse.
  36. The Single-Cell Level Perspective of the Tumor Microenvironment and Its Remodeling by CAR-T Cells.
  37. Dendritic Cells metabolism - a strategic path to improve antitumoral DC vaccination.
  38. Role of Metabolism in Adoptive T Cell Therapy: Strategies and Challenges.
  39. Targeting GCN2 Regulation of Amino Acid Homeostasis in Prostate Cancer.
  40. Application of Metabolite Set Enrichment Analysis (MSEA) on untargeted metabolomics data prioritizes relevant pathways and detects novel biomarkers for inherited metabolic disorders.
  41. Differentiation of circulating monocytes into macrophages with metabolically activated phenotype regulates inflammation in dyslipidemia patients.
  42. Paracrine regulation of adipose tissue macrophages by their neighbors in the micro-environment of obese adipose tissue.
  43. Multiomics identifies the link between intratumor steatosis and the exhausted tumor immune microenvironment in hepatocellular carcinoma.
  44. TBK1 participates in glutaminolysis by mediating the phosphorylation of RIPK3 to promote endotoxin tolerance.
  45. The lactate-NAD+ axis activates cancer-associated fibroblasts by downregulating p62.
  46. Glycogen Storage Disease Phenotypes Accompanying the Perturbation of the Methionine Cycle in NDRG3-Deficient Mouse Livers.
  1. Cancers (Basel). 2022 Apr 26. pii: 2151. [Epub ahead of print]14(9):
    Role of Amino Acid Transporter SNAT1/SLC38A1 in Human Melanoma.
    Ines Böhme-Schäfer, Sandra Lörentz, Anja Katrin Bosserhoff.
      The tumor metabolism is an important driver of cancer cell survival and growth, as rapidly dividing tumor cells exhibit a high demand for energetic sources and must adapt to microenvironmental changes. Therefore, metabolic reprogramming of cancer cells and the associated deregulation of nutrient transporters are a hallmark of cancer cells. Amino acids are essential for cancer cells to synthesize the necessary amount of protein, DNA, and RNA. Although cancer cells can synthesize glutamine de novo, most cancer cells show an increased uptake of glutamine from the tumor microenvironment. Especially SNAT1/SLC38A1, a member of the sodium neutral amino acid transporter (SNAT) family, plays an essential role during major net import of glutamine. In this study, we revealed a significant upregulation of SNAT1 expression in human melanoma tissue in comparison to healthy epidermis and an increased SNAT1 expression level in human melanoma cell lines when compared to normal human melanocytes (NHEMs). We demonstrated that functional inhibition of SNAT1 with α-(methylamino) isobutyric acid (MeAIB), as well as siRNA-mediated downregulation reduces cancer cell growth, cellular migration, invasion, and leads to induction of senescence in melanoma cells. Consequently, these results demonstrate that the amino acid transporter SNAT1 is essential for cancer growth, and indicates a potential target for cancer chemotherapy.
    Keywords:  amino acid transporter; melanoma; tumor metabolism
    DOI:  https://doi.org/10.3390/cancers14092151
  2. Cell Rep. 2022 May 10. pii: S2211-1247(22)00567-8. [Epub ahead of print]39(6): 110800
    A pan-cancer metabolic atlas of the tumor microenvironment.
    Neha Rohatgi, Umesh Ghoshdastider, Probhonjon Baruah, Tanmay Kulshrestha, Anders Jacobsen Skanderup.
      Tumors are heterogeneous cellular environments with entwined metabolic dependencies. Here, we use a tumor transcriptome deconvolution approach to profile the metabolic states of cancer and non-cancer (stromal) cells in bulk tumors of 20 solid tumor types. We identify metabolic genes and processes recurrently altered in cancer cells across tumor types, highlighting pan-cancer upregulation of deoxythymidine triphosphate (dTTP) production. In contrast, the tryptophan catabolism rate-limiting enzymes IDO1 and TDO2 are highly overexpressed in stroma, raising the hypothesis that kynurenine-mediated suppression of antitumor immunity may be predominantly constrained by the stroma. Oxidative phosphorylation is the most upregulated metabolic process in cancer cells compared to both stromal cells and a large atlas of cancer cell lines, suggesting that the Warburg effect may be less pronounced in cancer cells in vivo. Overall, our analysis highlights fundamental differences in metabolic states of cancer and stromal cells inside tumors and establishes a pan-cancer resource to interrogate tumor metabolism.
    Keywords:  CP: Cancer; CP: Metabolism; metabolism; tumor microenvironment
    DOI:  https://doi.org/10.1016/j.celrep.2022.110800
  3. Cells. 2022 Apr 23. pii: 1433. [Epub ahead of print]11(9):
    The Role of Extracellular Vesicles in Metabolic Reprogramming of the Tumor Microenvironment.
    Eran S Fridman, Lana Ginini, Ziv Gil.
      The tumor microenvironment (TME) includes a network of cancerous and non-cancerous cells, together with associated blood vessels, the extracellular matrix, and signaling molecules. The TME contributes to cancer progression during various phases of tumorigenesis, and interactions that take place within the TME have become targets of focus in cancer therapy development. Extracellular vesicles (EVs) are known to be conveyors of genetic material, proteins, and lipids within the TME. One of the hallmarks of cancer is its ability to reprogram metabolism to sustain cell growth and proliferation in a stringent environment. In this review, we provide an overview of TME EV involvement in the metabolic reprogramming of cancer and stromal cells, which favors cancer progression by enhancing angiogenesis, proliferation, metastasis, treatment resistance, and immunoevasion. Targeting the communication mechanisms and systems utilized by TME-EVs is opening a new frontier in cancer therapy.
    Keywords:  cancer metabolism; exosomes; extracellular vesicles (EVs); glycolysis; tumor microenvironment (TME)
    DOI:  https://doi.org/10.3390/cells11091433
  4. Cells. 2022 Apr 20. pii: 1392. [Epub ahead of print]11(9):
    Glucose Starvation or Pyruvate Dehydrogenase Activation Induce a Broad, ERK5-Mediated, Metabolic Remodeling Leading to Fatty Acid Oxidation.
    Abrar Ul Haq Khan, Hamideh Salehi, Catherine Alexia, Jose M Valdivielso, Milica Bozic, Isabel C Lopez-Mejia, Lluis Fajas, Sabine Gerbal-Chaloin, Martine Daujat-Chavanieu, Delphine Gitenay, Martin Villalba.
      Cells have metabolic flexibility that allows them to adapt to changes in substrate availability. Two highly relevant metabolites are glucose and fatty acids (FA), and hence, glycolysis and fatty acid oxidation (FAO) are key metabolic pathways leading to energy production. Both pathways affect each other, and in the absence of one substrate, metabolic flexibility allows cells to maintain sufficient energy production. Here, we show that glucose starvation or sustained pyruvate dehydrogenase (PDH) activation by dichloroacetate (DCA) induce large genetic remodeling to propel FAO. The extracellular signal-regulated kinase 5 (ERK5) is a key effector of this multistep metabolic remodeling. First, there is an increase in the lipid transport by expression of low-density lipoprotein receptor-related proteins (LRP), e.g., CD36, LRP1 and others. Second, an increase in the expression of members of the acyl-CoA synthetase long-chain (ACSL) family activates FA. Finally, the expression of the enzymes that catalyze the initial step in each cycle of FAO, i.e., the acyl-CoA dehydrogenases (ACADs), is induced. All of these pathways lead to enhanced cellular FAO. In summary, we show here that different families of enzymes, which are essential to perform FAO, are regulated by the signaling pathway, i.e., MEK5/ERK5, which transduces changes from the environment to genetic adaptations.
    Keywords:  ERK5; fatty acid oxidation; glycolysis; metabolic flexibility; metabolic plasticity
    DOI:  https://doi.org/10.3390/cells11091392
  5. FASEB J. 2022 May;36 Suppl 1
    Development of Cancer-on-a-chip Technology for the Study of Tumor Microenvironment and Metabolism.
    Daniel L Ericson, Joshua Azukas, Helmut H Strey, David Rubenstein.
      Cancer metabolism has become an area of intense interest. In the 1920s, Otto Warburg showed that cancer cells metabolize glucose to produce lactate and ATP in the presence of oxygen, i.e. aerobic glycolysis, also known as the Warburg Effect. It is now appreciated that cancer cells display a complex metabolic phenotype. Metabolic reprogramming by oncogenes and tumor suppressor genes has been linked to the altered metabolic function of cancer cells. However, the tumor microenvironment (TME), which has different nutrient gradients for glucose, oxygen, and amino acids, has a dramatic effect on cancer cell growth and proliferation. In vivo studies have demonstrated a heterogeneous metabolic phenotype that is difficult to characterize. In addition, the exchange of nutrients and metabolites between the TME, vasculature, and tumor cells has been difficult to fully recapitulate. As a tumor grows, nutrients diffuse from the blood vessels to the cancer cells, in a process partially described by A. Krogh in 1919 through a reaction-diffusion differential equation. Krogh's work showed that for typical tissues the oxygen decay radius is around 150μm and we find approximately the same 'Krogh radius' for high glucose consumption cancer cells (e.g. MDA-MB-231). Thus, around 150μm from a blood vessel exists an oxygen deprived environment that imposes tremendous competitive stresses on the cancer cells for survival. There is rising evidence that this selection pressure favors the transformation to metastasis and causes invasive tumor cell lines to exhibit high glycolytic rates and overall metabolic reprogramming. However, most studies focused on defining the metabolic function of tumor cells have been conducted in vitro, under conditions that do not represent the physiological conditions accurately. Here, we present a cancer-on-a-chip technology that produces a well-defined 3D TME that can be exposed to precise nutrient stresses such as varying oxygen or other nutrient gradients. In addition, we can determine the metabolic phenotype of cancer cells with varying oncogenic changes and degrees of aggressiveness. Our technology should be able to address the question of the role of the TME on metabolic reprogramming and in particular glycolysis. Our design is based on growing tumor microenvironments inside 360µm ID capillary tubing that can be accessed by 360µm PEEK tubing. To allow/control perfusion through the microenvironment we embed a 70µm nylon fiber into a photocross-linkable gelatin gel in which the cells are dispersed (MDA-MB-231/GFP). After exposing the gel to UV-light for a few seconds, the nylon fiber is pulled, leaving a perfusable microchannel. Using this technique, we have successfully perfused cell-laden hydrogels over weeks while observing cell-growth in a fluorescence microscope.
    DOI:  https://doi.org/10.1096/fasebj.2022.36.S1.R4284
  6. Am J Cancer Res. 2022 ;12(4): 1436-1455
    Targeting 2-oxoglutarate dehydrogenase for cancer treatment.
    Ling-Chu Chang, Shih-Kai Chiang, Shuen-Ei Chen, Mien-Chie Hung.
      Tricarboxylic acid (TCA) cycle, also called Krebs cycle or citric acid cycle, is an amphoteric pathway, contributing to catabolic degradation and anaplerotic reactions to supply precursors for macromolecule biosynthesis. Oxoglutarate dehydrogenase complex (OGDHc, also called α-ketoglutarate dehydrogenase) a highly regulated enzyme in TCA cycle, converts α-ketoglutarate (αKG) to succinyl-Coenzyme A in accompany with NADH generation for ATP generation through oxidative phosphorylation. The step collaborates with glutaminolysis at an intersectional point to govern αKG levels for energy production, nucleotide and amino acid syntheses, and the resources for macromolecule synthesis in cancer cells with rapid proliferation. Despite being a flavoenzyme susceptible to electron leakage contributing to mitochondrial reactive oxygen species (ROS) production, OGDHc is highly sensitive to peroxides such as HNE (4-hydroxy-2-nonenal) and moreover, its activity mediates the activation of several antioxidant pathways. The characteristics endow OGDHc as a critical redox sensor in mitochondria. Accumulating evidences suggest that dysregulation of OGDHc impairs cellular redox homeostasis and disturbs substrate fluxes, leading to a buildup of oncometabolites along the pathogenesis and development of cancers. In this review, we describe molecular interactions, regulation of OGDHc expression and activity and its relationships with diseases, specifically focusing on cancers. In the end, we discuss the potential of OGDHs as a therapeutic target for cancer treatment.
    Keywords:  2-oxoglutarate dehydrogenase; cancer metabolism; reactive oxygen species; tricarboxylic acid cycle; α-ketoglutarate dehydrogenase complex
  7. Cancers (Basel). 2022 Apr 29. pii: 2242. [Epub ahead of print]14(9):
    Labile Heme and Heme Oxygenase-1 Maintain Tumor-Permissive Niche for Endometriosis-Associated Ovarian Cancer.
    Jonathan L Hecht, Monika Janikova, Reeham Choudhury, Fong Liu, Giacomo Canesin, Lubica Janovicova, Eva Csizmadia, Elisa M Jorgensen, Katharine M Esselen, Peter Celec, Kenneth D Swanson, Barbara Wegiel.
      Endometriosis, a painful gynecological condition accompanied by inflammation in women of reproductive age, is associated with an increased risk of ovarian cancer. We evaluated the role of peritoneal heme accumulated during menstrual cycling, as well as peritoneal and lesional macrophage phenotype, in promoting an oncogenic microenvironment. We quantified the heme-degrading enzyme, heme oxygenase-1 (HO-1, encoded by Hmox1) in normal peritoneum, endometriotic lesions and endometriosis-associated ovarian cancer (EAOC) of clear cell type (OCCC). HO-1 was expressed primarily in macrophages and increased in endometrioma and OCCC tissues relative to endometriosis and controls. Further, we compared cytokine expression profiles in peritoneal macrophages (PM) and peripheral blood mononuclear cells (PBMC) in women with endometriosis versus controls as a measure of a tumor-promoting environment in the peritoneum. We found elevated levels of HO-1 along with IL-10 and the pro-inflammatory cytokines (IL-1β, IL-16, IFNγ) in PM but not in PBMC from endometriosis patients. Using LysM-Cre:Hmox1flfl conditional knockout mice, we show that a deficiency of HO-1 in macrophages led to the suppression of growth of ID8 ovarian tumors implanted into the peritoneum. The restriction of ID8 ovarian tumor growth was associated with an increased number of Mac3+ macrophage and B cells in LysM-Cre:Hmox1flfl mice compared to controls. Functional experiments in ovarian cancer cell lines show that HO-1 is induced by heme. Low levels of exogenous heme promoted ovarian cancer colony growth in soft agar. Higher doses of heme led to slower cancer cell colony growth in soft agar and the induction of HO-1. These data suggest that perturbation of heme metabolism within the endometriotic niche and in cancer cells themselves may be an important factor that influences tumor initiation and growth.
    Keywords:  endometriosis; heme oxygenase-1; hemopexin; labile heme; ovarian cancer
    DOI:  https://doi.org/10.3390/cancers14092242
  8. Cancers (Basel). 2022 Apr 29. pii: 2220. [Epub ahead of print]14(9):
    Tumor-Associated Macrophages and Ovarian Cancer: Implications for Therapy.
    David Schweer, Annabel McAtee, Khaga Neupane, Christopher Richards, Frederick Ueland, Jill Kolesar.
      The tumor microenvironment (TME) has been implicated to play an important role in the progression of ovarian cancer. One of the most important components of the TME is tumor associated macrophages (TAMs). Phenotypically, macrophages are broadly categorized as M1 pro-inflammatory or M2 anti-inflammatory, based on the cytokines and chemokines that they secrete. The tumor microenvironment is associated with macrophages of an M2 phenotype which suppress the surrounding immune environment, assist tumor cells in evading immune targeting, and support tumor growth and metastasis. Contrarily, M1 macrophages help mount an immune response against tumors, and are associated with a more favorable prognosis in solid tumors. One of the characteristic indicators of a poor prognosis in ovarian cancer is the overrepresentation of M2-type TAMs. As such, therapeutic modalities targeting TME and TAMs are of increasing interest. Pharmacological approaches to eliminate TAMs, include decreasing macrophage survival and recruitment and increasing phagocytosis, have been underwhelming. Clinical strategies targeting these macrophage subtypes via repolarization to an M1 antitumoral state deserve increasing attention, and may serve as a new modality for immunotherapy.
    Keywords:  TAM; immunotherapy; macrophages; ovarian cancer; repolarization
    DOI:  https://doi.org/10.3390/cancers14092220
  9. Curr Heart Fail Rep. 2022 May 14.
    Targeting Myocardial Substrate Metabolism in the Failing Heart: Ready for Prime Time?
    Salva R Yurista, Shi Chen, Aidan Welsh, W H Wilson Tang, Christopher T Nguyen.
      PURPOSE OF REVIEW: We review the clinical benefits of altering myocardial substrate metabolism in heart failure.RECENT FINDINGS: Modulation of cardiac substrates (fatty acid, glucose, or ketone metabolism) offers a wide range of therapeutic possibilities which may be applicable to heart failure. Augmenting ketone oxidation seems to offer great promise as a new therapeutic modality in heart failure. The heart has long been recognized as metabolic omnivore, meaning it can utilize a variety of energy substrates to maintain adequate ATP production. The adult heart uses fatty acid as a major fuel source, but it can also derive energy from other substrates including glucose and ketone, and to some extent pyruvate, lactate, and amino acids. However, cardiomyocytes of the failing heart endure remarkable metabolic remodeling including a shift in substrate utilization and reduced ATP production, which account for cardiac remodeling and dysfunction. Research to understand the implication of myocardial metabolic perturbation in heart failure has grown in recent years, and this has raised interest in targeting myocardial substrate metabolism for heart failure therapy. Due to the interdependency between different pathways, the main therapeutic metabolic approaches include inhibiting fatty acid uptake/fatty acid oxidation, reducing circulating fatty acid levels, increasing glucose oxidation, and augmenting ketone oxidation.
    Keywords:  Cardiac metabolism; Fatty acid; Glucose; Heart failure; Ketone bodies
    DOI:  https://doi.org/10.1007/s11897-022-00554-1
  10. Biochim Biophys Acta Mol Basis Dis. 2022 May 06. pii: S0925-4439(22)00097-7. [Epub ahead of print]1868(9): 166427
    d-2-Hydroxyglutarate is an anti-inflammatory immunometabolite that accumulates in macrophages after TLR4 activation.
    Kyra E de Goede, Karl J Harber, Friederike S Gorki, Sanne G S Verberk, Laszlo A Groh, Eelco D Keuning, Eduard A Struys, Michel van Weeghel, Arvand Haschemi, Menno P J de Winther, Xanthe A M H van Dierendonck, Jan Van den Bossche.
      Macrophages undergo extensive metabolic rewiring upon activation which assist the cell in roles beyond energy production and synthesis of anabolic building blocks. So-called immunometabolites that accumulate upon immune activation can serve as co-factors for enzymes and can act as signaling molecules to modulate cellular processes. As such, the Krebs-cycle-associated metabolites succinate, itaconate and alpha-ketoglutarate (αKG) have emerged as key regulators of macrophage function. Here, we describe that 2-hydroxyglutarate (2HG), which is structurally similar to αKG and exists as two enantiomers, accumulates during later stages of LPS-induced inflammatory responses in mouse and human macrophages. D-2HG was the most abundant enantiomer in macrophages and its LPS-induced accumulation followed the induction of Hydroxyacid-Oxoacid Transhydrogenase (HOT). HOT interconverts αKG and gamma-hydroxybutyrate into D-2HG and succinic semialdehyde, and we here identified this enzyme as being immune-responsive and regulated during the course of macrophage activation. The buildup of D-2HG may be further explained by reduced expression of D-2HG Dehydrogenase (D2HGDH), which converts D-2HG back into αKG, and showed inverse kinetics with HOT and D-2HG levels. We tested the immunomodulatory effects of D-2HG during LPS-induced inflammatory responses by transcriptomic analyses and functional profiling of D-2HG-pre-treated macrophages in vitro and mice in vivo. Together, these data suggest a role for D-2HG in the negative feedback regulation of inflammatory signaling during late-stage LPS-responses in vitro and as a regulator of local and systemic inflammatory responses in vivo. Finally, we show that D-2HG likely exerts distinct anti-inflammatory effects, which are in part independent of αKG-dependent dioxygenase inhibition. Together, this study reveals an immunometabolic circuit resulting in the accumulation of the immunomodulatory metabolite D-2HG that can inhibit inflammatory macrophage responses.
    Keywords:  2-HG; 2-hydroxyglutarate; Immunometabolism; Immunometabolite; Innate immunity; Macrophage
    DOI:  https://doi.org/10.1016/j.bbadis.2022.166427
  11. Cancers (Basel). 2022 Apr 30. pii: 2262. [Epub ahead of print]14(9):
    Space- and Time-Resolved Metabolomics of a High-Grade Serous Ovarian Cancer Mouse Model.
    Samyukta Sah, Xin Ma, Andro Botros, David A Gaul, Sylvia R Yun, Eun Young Park, Olga Kim, Samuel G Moore, Jaeyeon Kim, Facundo M Fernández.
      The dismally low survival rate of ovarian cancer patients diagnosed with high-grade serous carcinoma (HGSC) emphasizes the lack of effective screening strategies. One major obstacle is the limited knowledge of the underlying mechanisms of HGSC pathogenesis at very early stages. Here, we present the first 10-month time-resolved serum metabolic profile of a triple mutant (TKO) HGSC mouse model, along with the spatial lipidome profile of its entire reproductive system. A high-coverage liquid chromatography mass spectrometry-based metabolomics approach was applied to longitudinally collected serum samples from both TKO (n = 15) and TKO control mice (n = 15), tracking metabolome and lipidome changes from premalignant stages to tumor initiation, early stages, and advanced stages until mouse death. Time-resolved analysis showed specific temporal trends for 17 lipid classes, amino acids, and TCA cycle metabolites, associated with HGSC progression. Spatial lipid distributions within the reproductive system were also mapped via ultrahigh-resolution matrix-assisted laser desorption/ionization (MALDI) mass spectrometry and compared with serum lipid profiles for various lipid classes. Altogether, our results show that the remodeling of lipid and fatty acid metabolism, amino acid biosynthesis, TCA cycle and ovarian steroidogenesis are critical components of HGSC onset and development. These metabolic alterations are accompanied by changes in energy metabolism, mitochondrial and peroxisomal function, redox homeostasis, and inflammatory response, collectively supporting tumorigenesis.
    Keywords:  biomarkers; high-grade serous ovarian cancer; imaging; mass spectrometry; metabolomics
    DOI:  https://doi.org/10.3390/cancers14092262
  12. FASEB J. 2022 May;36 Suppl 1
    Glucose-1-phosphate regulates orphan nuclear receptor NR4A1 and apoptosis.
    Young-Sam Lee, Hyungjoo Shon, Abigail E Rockenhaus.
      Mitochondrial metabolic reprogramming is important for many different processes like apoptosis and inflammation. NR4A1 is necessary for many different pro-apoptotic and inflammatory stimuli to induce mitochondrial metabolic reprogramming. However, despite the importance for small molecule ligands in the regulation of nuclear receptors, biological ligands regulating NR4A1 have not been identified. Here we report that glucose-1-phosphate (G1P), an intracellular metabolite from glycogen metabolism and glycolysis, is an NR4A1 ligand. In vitro, G1P specifically bound to NR4A1 ligand-binding domain (NR4A1LBD ) and alters its oligomerization state. In cells, a synthetic cell-permeable G1P analog regulates transcriptional activity of NR4A1. This G1P analog suppressed mitochondrial respiration and induced apoptosis of H1299 lung adenocarcinoma cells in an NR4A1-dependent manner. This result suggests that G1P might be an endogenous ligand regulating NR4A1 and NR4A1-dependent mitochondrial metabolic reprogramming. It represents a rare case where a polar water-soluble intracellular metabolite modulates a nuclear receptor function.
    DOI:  https://doi.org/10.1096/fasebj.2022.36.S1.0R474
  13. Theranostics. 2022 ;12(7): 3534-3552
    SCD1/FADS2 fatty acid desaturases equipoise lipid metabolic activity and redox-driven ferroptosis in ascites-derived ovarian cancer cells.
    Yang Xuan, Huogang Wang, Mingo Mh Yung, Fushun Chen, Wai-Sun Chan, Yau-Sang Chan, Stephen Kw Tsui, Hextan Ys Ngan, Karen Kl Chan, David W Chan.
      Rationale: Malignant ascites in peritoneal metastases is a lipid-enriched microenvironment and is frequently involved in the poor prognosis of epithelial ovarian cancer (EOC). However, the detailed mechanisms underlying ovarian cancer (OvCa) cells dictating their lipid metabolic activities in promoting tumor progression remain elusive. Methods: The omental conditioned medium (OCM) was established to imitate the omental or ascites microenvironment. Mass spectrometry, RT-qPCR, IHC, and western blot assays were applied to evaluate human fatty acid desaturases expressions and activities. Pharmaceutical inhibition and genetic ablation of SCD1/FADS2 were performed to observe the oncogenic capacities. RNA sequencing, lipid peroxidation, cellular iron, ROS, and Mito-Stress assays were applied to examine ferroptosis. OvCa patient-derived organoid and mouse model of peritoneal metastases were used to evaluate the combined effect of SCD1/FADS2 inhibitors with cisplatin. Results: We found that two critical fatty acid desaturases, stearoyl-CoA desaturase-1 (SCD1) and acyl-CoA 6-desaturase (FADS2), were aberrantly upregulated, accelerating lipid metabolic activities and tumor aggressiveness of ascites-derived OvCa cells. Lipidomic analysis revealed that the elevation of unsaturated fatty acids (UFAs) was positively associated with SCD1/FADS2 levels and the oncogenic capacities of OvCa cells. In contrast, pharmaceutical inhibition and genetic ablation of SCD1/FADS2 retarded tumor growth, cancer stem cell (CSC) formation and reduced platinum resistance. Inhibition of SCD1/FADS2 directly downregulated GPX4 and the GSH/GSSG ratio, causing disruption of the cellular/mitochondrial redox balance and subsequently, iron-mediated lipid peroxidation and mitochondrial dysfunction in ascites-derived OvCa cells. Conclusions: Combinational treatment with SCD1/FADS2 inhibitors and cisplatin synergistically repressed tumor cell dissemination, providing a promising chemotherapeutic strategy against EOC peritoneal metastases.
    Keywords:  lipid desaturases; lipid metabolism; ovarian cancer; oxidative stress; peritoneal metastases
    DOI:  https://doi.org/10.7150/thno.70194
  14. FASEB J. 2022 May;36 Suppl 1
    Mechanistic basis for the allosteric activation of mitochondrial glutaminase C, a key driver of glutamine metabolism in cancer cells.
    Thuy-Tien T Nguyen, Sekar Ramachandran, Matthew J Hill, Richard A Cerione.
      The dependence of cancer cells on glutamine metabolism, the most abundant amino acid in plasma, has been observed in many highly aggressive and deadly cancers including pancreatic cancer, triple-negative breast cancer, and glioblastoma. The mitochondrial enzyme glutaminase C (GAC) catalyzes the hydrolysis of glutamine to glutamate, the first step in glutamine metabolism, highlighting GAC as a potentially important therapeutic target. GAC acquires maximal catalytic activity upon binding to anionic activators like inorganic phosphate. To delineate the mechanism of GAC activation, we used the tryptophan substitution of tyrosine 466 in the catalytic site of the enzyme as a fluorescence reporter for glutamine binding in the presence and absence of phosphate. We show that in the absence of phosphate, glutamine binding to the GAC (Y466W) tetramer exhibits positive cooperativity. A high-resolution X-ray structure of tetrameric GAC (Y466W) bound to glutamine suggests that cooperativity in substrate binding is coupled to tyrosine 249, located at the edge of the catalytic site (i.e. designated the 'lid'), adopting two distinct conformations. In one dimer within the GAC tetramer, the lids are open and glutamine binds weakly, whereas, in the adjoining dimer, the lids are closed over the substrates resulting in higher affinity interactions. When crystallized in the presence of glutamine and phosphate, all four subunits of the GAC (Y466W) tetramer have bound glutamine with closed lids. Glutamine now binds with high affinity to each subunit, which then undergo simultaneous catalysis. These findings show how the regulated transitioning of GAC between different conformational states ensures maximal catalytic activity is reached in cancer cells only when an allosteric activator is available.
    DOI:  https://doi.org/10.1096/fasebj.2022.36.S1.R2820
  15. FASEB J. 2022 May;36 Suppl 1
    Limiting Mitochondrial Magnesium Exacerbates Ketogenic Insufficiency and Alters Hepatic Lipid Metabolism.
    Shanmughapriya Santhanam, Prema Velusamy, Thiruvelselvan Ponnusamy, Natarajaseenivasan Kalimuthusamy, Sarah S Bingaman, Amy C Arnold.
      Mg2+ is an abundant intracellular cation and an important co-factor in the machineries that replicate, transcribe and translate genomic information. Like Ca2+ , Mg2+ is also compartmentalized to mitochondria, which are known to accumulate and release Mg2+ in response to metabolic stimuli and thus regulate the intracellular Mg2+ (iMg2+ ) levels. Mrs2, is the only known molecular machinery associated with mitochondrial Mg2+ (mMg2+ )influx. Though the core component of the mMg2+ influx is defined, our understanding of how mMg2+ homeostasis alters iMg2+ and the metabolic state of the cell remains incomplete. To begin elucidating the importance of mMg2+ , we made a liver-specific Mrs2 knockout mouse (KO) using the Cre-loxP system. Liver being the central hub of lipid metabolism, we asked whether loss of mMg2+ alters hepatic lipid homeostasis. Our results show Mrs2 KO mice to accumulate intrahepatic lipid. To understand the molecular mechanism of the altered lipid accumulation, we performed a global proteome analysis in ad libitum fed state liver. We observed PPARα-regulated targets to be differentially upregulated in Mrs2 KO. Our results show that in Mrs2 KO, Mg2+ -activated binding of AMPK/PPARα co-activates PPARα to increase target gene expression. PPARα activation is known to increase the maximal fatty acid oxidization (FAO) in the liver but it is intriguing to observe intrahepatic lipid accumulation in Mrs2 KO. To understand this unusual relationship, we measured acetyl coA (AcCOA). In line with increased expression of FAO proteins, we observed AcCOA levels to be increased in Mrs2 KO. Since under homeostatic conditions, FAO derived AcCOA can be channeled to ketogenesis (Fig. 1 left panel), we anticipated robust ketogenesis in Mrs2 KO. Our results show no change in circulating ketone bodies (KB) in Mrs2 KO, however, revealing a state of ketogenic insufficiency. Additionally, our results show that in the setting of ketogenic insufficiency (Fig. 1 middle panel), the FAO-derived AcCOA is exported to the cytoplasm as citrate. We also show the increased cytosolic citrate levels to positively correlate with increased de novo lipogenesis (DNL) via cataplerosis, resulting in excessive accumulation of diacyl glycerols (DAG) and triacyl glycerols (TAG). Though evidence exists on the regulation of lipid metabolism by Mg2+ , the underlying molecular mechanism by which Mg2+ regulates lipid metabolism is an unanswered question for decades. Results from our study is the first of its kind to uncover new pathways through which Mg2+ regulates hepatic lipid metabolism. Future directions: Since increased DNL can trigger hepatic insulin resistance (IR) via DAG-mediated activation of PKCε, for our future study we hypothesize Mrs2 KO to be insulin resistant in the extreme circumstance of ketogenic insufficiency and a high-fat load (Fig. 1 right panel). We anticipate FAO-derived acetyl-CoA to sequester Coenzyme A and disrupt the tricarboxylic acid (TCA) cycle, resulting in excessive DNL, DAG/TAG accumulation, and hepatic IR through PKCε activation, thus iterating a triad relationship of mMg2+ homeostasis, hepatic lipid metabolism, and IR.
    DOI:  https://doi.org/10.1096/fasebj.2022.36.S1.R3136
  16. FASEB J. 2022 May;36 Suppl 1
    Novel Roles of FFAR4 in Macrophage Foam Cell Formation.
    Gage M Stuttgen, Daisy Sahoo.
      Free fatty acid receptor 4 (FFAR4), also known as G-protein coupled receptor 120 (GPR120), is a long-chain unsaturated fatty acid receptor expressed in adipocytes, endothelial cells, and macrophages. Activation of FFAR4 helps maintain metabolic homeostasis by regulating adipogenesis, insulin sensitivity, and inflammation. While FFAR4 is best known for its role its role in preventing obesity and diabetes, recent studies have demonstrated that FFAR4 may also play an important role in the development of atherosclerosis and cardiovascular disease (CVD). Given FFAR4's importance in anti-inflammatory signaling and high expression levels in macrophages, we designed experiments to test the hypothesis that FFAR4 prevents the development of atherosclerosis by reversing macrophage foam cell formation, a hallmark of early atherogenesis. In these studies, we isolated peritoneal macrophages from wild-type C57/BL6J mice and incubated them with oxidized low-density lipoprotein (oxLDL) to generate foam cells. We then investigated the effects of FFAR4 activation by GW9508 (a synthetic agonist) on lipid accumulation, cytokine secretion, and cholesterol efflux. Activation of FFAR4 by GW9508 decreased macrophage secretion of pro-inflammatory cytokines. We also found that activation of FFAR4 with GW9508 reduced lipid accumulation in macrophages as observed by decreased Oil Red O staining and reduced cellular cholesterol content. Additionally, activation of FFAR4 by GW9508 increased [3 H]-cholesterol efflux to high-density lipoprotein (HDL). Interestingly, the increased efflux was accompanied by decreased scavenger receptor CD36 expression (that mediates oxLDL uptake) and increased expression of ATP binding cassette transporters, ABCA1 and ABCG1 (that mediate cholesterol efflux). Taken together, our results support an exciting and novel role for FFAR4 in the reversal of foam cell formation and could emerge this receptor as a new target for treating CVD by preventing accumulation of atherosclerotic plaque.
    DOI:  https://doi.org/10.1096/fasebj.2022.36.S1.0R852
  17. FASEB J. 2022 May;36 Suppl 1
    Lipid Metabolism and Ferroptosis.
    Scott Dixon.
      Ferroptosis is an oxidative, iron-dependent form of non-apoptotic cell death that contributes to several forms of pathology and may be exploitable for cancer therapy. Ferroptosis can be induced using small molecule inhibitors of the plasma membrane cystine/glutamate antiporter system xc - or the glutathione-dependent lipid hydroperoxidase glutathione peroxidase 4 (GPX4). The execution of ferroptosis requires membrane lipid peroxidation, but specific lipids and lipid metabolic enzymes that are involved in this process are only partly characterized. How ferroptosis sensitivity relates to other fundamental cellular processes such as the cell cycle is also unclear. We find that inhibition of the Rb-E2F cell cycle pathway causes downregulation of specific lipid metabolic enzymes, leading to an increase in polyunsaturated phospholipid abundance. In turn, this metabolic alteration specifically enhances ferroptosis sensitivity. Drugs that inhibit Rb-E2F pathway function synergize with a ferroptosis-inducing small molecule to arrest tumor growth in vivo. These results suggest that ferroptosis sensitivity may be linked to cell cycle progression through specific alterations in membrane phospholipid composition.
    DOI:  https://doi.org/10.1096/fasebj.2022.36.S1.0I209
  18. FASEB J. 2022 May;36 Suppl 1
    Interleukin 21-induced Mitochondrial Dysfunction Drives Regulatory T Cell Inflammatory Response during Intestinal Inflammation.
    Adebowale O Bamidele, Mary R Sagstetter, Petra Hirsova, Guilherme P Ramos, Emily Klatt, Maria Westphal, William Faubion.
      BACKGROUND: Significant proportion of inflammatory bowel disease (IBD) patients continue to respond inconsistently to therapies, underscoring disease complexity and the need for efficacious treatment. Interleukin 21 (IL-21), which is known to support T helper (Th) cell function, is highly expressed within inflamed intestinal tissues of IBD patients compared to healthy controls. In addition, inflammatory regulatory T cells (Tregs) have been linked to refractory human IBD. Given that healthy Tregs are critical for self-tolerance and prevention of IBD, we investigated the metabolic role of IL-21 in instigating Treg dysfunction and the therapeutic ramifications of targeting metabolism pathways during IBD pathogenesis.METHODS: Human Tregs as well as relevant control effector Th cells were generated from naïve CD4+ T cells isolated from healthy blood donors. Microarray analysis was utilized for targeted metabolic transcriptional profiling. Immune phenotyping was assessed by fluorescence-activated cell sorting. Metabolic phenotyping of cells was assessed by Seahorse flux analysis and mass spectrometry-based metabolomics. Ultrastructural analysis of mitochondria was performed by confocal and transmission electron microscopy. Intestinal inflammation was induced in Rag1-/- (T and B cell deficient) mice by the adoptive transfer of pathogenic naïve CD4+ T cells.
    RESULTS: Acute IL-21 stimulation of human Tregs induced glycolysis and fluctuations in mitochondrial respiration (i.e. oxidative phosphorylation - OXPHOS), as assessed by Seahorse flux analysis. In agreement, microarray analysis, validated by qPCR, revealed an IL-21-mediated increase in the expression of genes associated with glycolysis and pathways known to support anabolic and OXPHOS metabolism, thus resembling a hypermetabolic state. Furthermore, IL-21 stimulation rendered Tregs susceptible to inflammatory response, as evidenced by the production of effector Th cell-associated cytokines such as interferon γ, tumor necrosis factor, IL-17A, and IL-17F. Exploring the mechanisms underlying IL-21-induced effects, we found significant disruption of mitochondrial integrity with concomitant activation of glycogen synthase kinase 3 (GSK3) β, a kinase known to prevent pyruvate entry into the mitochondria. IL-21-induced GSK3β activation was accompanied by a marked increase in intracellular and extracellular metabolites such as pyruvate and lactate, as assessed by metabolomics. Importantly, GSK3 inhibition or supplementation with mitochondrial membrane-permeable methyl pyruvate broadly abrogated metabolic wiring of and inflammatory responses by IL-21-stimulated Tregs and effector Th cells. Collectively, these results suggest that impaired mitochondrial pyruvate metabolism is a feature of inflammatory CD4+ T cells. Lastly, GSK3 inhibition prevented pathogenic CD4+ T cell-induced colitis in mice as evidenced by reduced Disease Activity Index, Mouse Colon Histology Index, and serum inflammatory cytokines.
    CONCLUSIONS: IL-21 potently engages human Tregs in a hypermetabolic state that augments inflammatory cytokine production via induction of mitochondrial dysfunction. Therefore desensitizing CD4+ T cells to detrimental cues, such as IL-21, may also augment Treg function during human IBD.
    DOI:  https://doi.org/10.1096/fasebj.2022.36.S1.R5953
  19. Comput Math Methods Med. 2022 ;2022 2807354
    Comprehensive Analysis of Subtypes and Identification of Key lncRNAs Based on Glutamine Metabolism-Related Long Noncoding RNAs.
    Yuwei Feng, Xiaowei Sun, Tiangu Yang, Jingqi Han, Dapeng Zhou, Haitao Ren, Yulong Sheng, Yanhua Wang.
      Background: Long noncoding RNAs (lncRNAs) are becoming a critical class of metabolic regulate molecule in cancer. Glutamine is a regulator that contributes to each of the core metabolic tasks in proliferating tumor cells. Thus, we aimed to evaluate the association of lncRNAs with glutamine metabolism in lung adenocarcinoma (LUAD).Methods: Using single-sample gene set enrichment analysis (ssGSEA), LUAD specimens were assigned scores based on glutamine metabolism-related genes, and the shared common glutamine metabolism-related lncRNAs in three different LUAD data cohorts were identified. ConsensusClusterPlus was used to perform unsupervised clustering analysis in patients with LUAD. Key glutamine metabolism-related lncRNAs were identified by first-order partial correlation analysis.
    Results: A total of 11 shared glutamine metabolism-associated lncRNAs were identified in three LUAD data cohorts, and LUAD patients were classified into three glutamine metabolism subtypes based on the expressions of the related genes. C1 exhibited shorter overall survival (OS), poor genomic instability, and inadequate infiltration of immune cell types in the tumor microenvironment (TME) and was representative of the immunodeficiency phenotype. C2 represented the immunosuppressive phenotype while C3 represented the immune activation phenotype, exhibiting the highest sensitivity to immunotherapy. Nine of the 11 lncRNAs were localized to the nucleus. Finally, three key lncRNAs, significantly enriched in multiple metabolic pathways, were screened and found to be remarkably related to the OS of LUAD.
    Conclusion: We identified three glutamine metabolism subtypes of LUAD, which reflected different OS, genomic, and TME features, and identified three key glutamine metabolism-associated lncRNAs may contribute to further study of lncRNAs in cancer metabolism.
    DOI:  https://doi.org/10.1155/2022/2807354
  20. FASEB J. 2022 May;36 Suppl 1
    Elucidating the role of NUDT19 in renal lipid metabolism.
    Rachel D King, Schuyler Vickers, Judy King, Roberta Leonardi.
      Coenzyme A (CoA) is an essential cofactor that plays a key role in fuel metabolism, as it is required for glucose oxidation and the synthesis and oxidation of fatty acids, amino acids, and ketone bodies. Three Nudix hydrolases, NUDT7, NUDT8, and NUDT19, hydrolyze CoA species at the phosphodiester bond, potentially contributing to the regulation of specific metabolic processes in the subcellular compartments where they reside. NUDT19 is found in the peroxisomes and is highly expressed in kidney proximal tubule cells (PTC). In vitro, NUDT19 readily hydrolyzes short and medium chain acyl-CoAs, malonyl- and succinyl-CoA, as well as free CoA. This substrate preference, combined with the peroxisomal localization of NUDT19, suggests a potential role in the regulation of peroxisomal lipid metabolism. To investigate the physiological function of NUDT19, we obtained global Nudt19-/- mice and fed them a high fat diet (HFD) or a low fat control diet (CD) for 15 weeks. On either diet, Nudt19-/- mice exhibit higher total CoA levels compared to wild type mice, indicating that NUDT19 contributes to the regulation of this cofactor. HFD feeding led to a higher albumin-to-creatinine ratio in the Nudt19-/- mice compared to wild type mice, indicating a decrease in kidney function. Nudt19-/- mice also exhibited elevated serum triglycerides and a higher body weight, not associated with changes in bone density or adiposity. In mice fed the HFD, deletion of Nudt19 caused only a few changes to the kidney cortex proteome, with only 8 proteins significantly altered, including 3 involved in peroxisomal and mitochondria fatty acid oxidation, which were increased in the kidneys of the Nudt19-/- mice. Measurement of mitochondrial and peroxisomal fatty acid oxidation using 14C-palmitate in kidney cortex slides did not reveal any differences between genotypes. Conversely, untargeted metabolomics analysis on whole kidneys revealed a general decrease in multiple lipid classes including lysophospholipids, monoacylglycerols, and long chain free fatty acids, without changes in triglycerides levels. Combined, the data support the conclusion that deletion of Nudt19 alters lipid metabolism.
    DOI:  https://doi.org/10.1096/fasebj.2022.36.S1.L7653
  21. Front Cell Dev Biol. 2022 ;10 885717
    Editorial: Metabolite and Nutrient Transporters in Cancer-Cell Metabolism: Role in Cancer Progression and Metastasis.
    Vadivel Ganapathy, Sebastian Haferkamp, Eric K Parkinson, Maria E Mycielska.
      
    Keywords:  Warburg effect; amino acids; cancer-cell metabolism; carnitine; citrate; glucose; metabolomics; nutrient/acid/base transporters
    DOI:  https://doi.org/10.3389/fcell.2022.885717
  22. Cancers (Basel). 2022 May 06. pii: 2303. [Epub ahead of print]14(9):
    LDH-A-Modulation and the Variability of LDH Isoenzyme Profiles in Murine Gliomas: A Link with Metabolic and Growth Responses.
    Masahiro Shindo, Masatomo Maeda, Ko Myat, Mayuresh M Mane, Ivan J Cohen, Kiranmayi Vemuri, Avi S Albeg, Inna Serganova, Ronald Blasberg.
      Three murine glioma cell lines (GL261, CT2A, and ALTS1C1) were modified to downregulate the expression of the murine LDH-A gene using shRNA, and compared to shRNA scrambled control (NC) cell lines. Differences in the expression of LDH-A and LDH-B mRNA, protein and enzymatic activity, as well as their LDH isoenzyme profiles, were observed in the six cell lines, and confirmed successful LDH-A KD. LDH-A KD (knock-down) resulted in metabolic changes in cells with a reduction in glycolysis (GlycoPER) and an increase in basal respiratory rate (mitoOCR). GL261 cells had a more limited ATP production capacity compared to CT2A and ALTS1C1 cells. An analysis of mRNA expression data indicated that: (i) GL261 LDH-A KD cells may have an improved ability to metabolize lactate into the TCA cycle; and (ii) that GL261 LDH-A KD cells can upregulate lipid metabolism/fatty acid oxidation pathways, whereas the other glioma cell lines do not have this capacity. These two observations suggest that GL261 LDH-A KD cells can develop/activate alternative metabolic pathways for enhanced survival in a nutrient-limited environment, and that specific nutrient limitations have a variable impact on tumor cell metabolism and proliferation. The phenotypic effects of LDH-A KD were compared to those in control (NC) cells and tumors. LDH-A KD prolonged the doubling time of GL261 cells in culture and prevented the formation of subcutaneous flank tumors in immune-competent C57BL/6 mice, whereas GL261 NC tumors had a prolonged growth delay in C57BL/6 mice. In nude mice, both LDH-A KD and NC GL261 tumors grew rapidly (more rapidly than GL261 NC tumors in C57BL/6 mice), demonstrating the impact of an intact immune system on GL261 tumor growth. No differences between NC and KD cell proliferation (in vitro) or tumor growth in C57BL/6 mice (doubling time) were observed for CT2A and ALTS1C1 cells and tumors, despite the small changes to their LDH isoenzyme profiles. These results suggest that GL261 glioma cells (but not CT2A and ALTS1C1 cells) are pre-programmed to have the capacity for activating different metabolic pathways with higher TCA cycle activity, and that this capacity is enhanced by LDH-A depletion. We observed that the combined impact of LDH-A depletion and the immune system had a significant impact on the growth of subcutaneous-located GL261 tumors.
    Keywords:  LDH isoenzymes; LDH-A and LDH-B immunohistochemistry; LDH-A shRNA knock-down; glioblastoma; immune-competent and incompetent host animals; tumor growth
    DOI:  https://doi.org/10.3390/cancers14092303
  23. FASEB J. 2022 May;36 Suppl 1
    Transcriptome and Mass-Spectrometry-Based Lipidome Reveal a Role of PRMT5 in Membrane Transport and Cholesterol Synthesis in White Adipocytes.
    Xiyue Chen, Zhihao Jia, Shuyi Fang, Feng Yue, Christina R Ferreria, Jun Wan, Shihuan Kuang.
      Adipose tissue (AT) regulates systemic energy homeostasis, and its dysfunction can result in insulin resistance and other metabolic complications. Protein arginine methyltransferase 5 (PRMT5) catalyzes symmetrical demethylation of arginine residues to modulate protein stability and/or function. Besides its well-studied oncogenic functions, PRMT5 has recently been shown to play a physiological role in AT through poorly understood mechanisms. Here, we combine RNA sequencing and mass-spectrometry-based lipidomic analyses of wildtype and Prmt5 knockout (Prmt5AKO ) AT to uncover the molecular mechanisms underlying PRMT5 function. We found that Prmt5AKO alters expression of genes related to metabolism and membrane transport. Specifically, Prmt5AKO induces genes enriched in glucose transport and glycolysis pathways, and suppresses genes encoding fatty acid (FA) transporters. This is accompanied by changes in lipid compositions of TAGs, FAs, and phospholipids. The data indicate that Prmt5AKO disrupts fatty acid metabolism while promoting glucose uptake and glycolysis. Prmt5AKO also promotes cholesterol biogenesis, contributing to hyperlipidemia and hepatic steatosis in mice. The omics data together reveal a previously unappreciated role of PRMT5 in membrane transport that affects glucose metabolism and cholesterol synthesis.
    DOI:  https://doi.org/10.1096/fasebj.2022.36.S1.L6381
  24. Lipids Health Dis. 2022 May 13. 21(1): 43
    Identification of a novel lipid metabolism-related gene signature within the tumour immune microenvironment for breast cancer.
    Xu Chang, Peng Xing.
      BACKGROUND: Systemic factors can strongly affect how tumour cells behave, grow, and communicate with other cells in breast cancer. Lipid metabolic reprogramming is a systemic process that tumour cells undergo; however, the formation and dynamics of lipids associated with the tumour immune microenvironment (TIME) remain unclear. The investigation of the sophisticated bidirectional crosstalk of tumour cells with cancer metabolism, gene expression, and TIME could have the potential to identify novel biomarkers for diagnosis, prognosis, and immunotherapy. This study aimed to construct a prognostic signature to detect the bicrosstalk between the lipid metabolic system and the TIME of breast cancer.METHODS: To detect the expression of LRGs and execute GO/KEGG analysis, the R program was chosen. Considering the clinical information and pathological features, a prognostic gene signature was constructed by LASSO Cox regression analysis. TMB, MSI, and immune infiltration analyses were performed, and consensus cluster analysis of LRGs was also performed.
    RESULTS: These 16 lipid metabolism-related genes (LRGs) were mainly involved in the process of lipid metabolism and fatty acid binding in breast cancer. Prognosis analysis identified the prognostic value of FABP7(Fatty acid binding protein 7) and NDUFAB1(NADH:ubiquinone oxidoreductase subunit AB1) in breast cancer patients. The prognostic gene signature constructed with FABP7 and NDUFAB1 was significantly related to immune cell infiltration and could predict the overall survival rate with above average correctness of breast cancer patients. FABP7 and NDUFAB1 were proven to have relevance in immune cell infiltration and tumour mutation burden (TMB). Consensus cluster analysis identified that the upregulated mRNAs were mostly related to the oncogenesis process, while the downregulated mRNAs were associated with immune-related signalling pathways.
    CONCLUSION: A comprehensive analysis was performed to evaluate the lipid metabolic system and identified a signature constructed by two prognostic genes for immunotherapies in breast cancer. The results also revealed evidence of vulnerabilities in the interplay between the lipid metabolic system and the TIME in breast cancer. Further data with clinical studies and experiments are warranted.
    Keywords:  Breast cancer; Immune-related analysis; Immunotherapy; Lipid metabolism; Tumour immune microenvironment
    DOI:  https://doi.org/10.1186/s12944-022-01651-9
  25. Cell Rep. 2022 May 10. pii: S2211-1247(22)00563-0. [Epub ahead of print]39(6): 110796
    Lipogenesis mediated by OGR1 regulates metabolic adaptation to acid stress in cancer cells via autophagy.
    Smitha Pillai, Iqbal Mahmud, Rohit Mahar, Crystal Griffith, Michael Langsen, Jonathan Nguyen, Jonathan W Wojtkowiak, Pawel Swietach, Robert A Gatenby, Marilyn M Bui, Matthew E Merritt, Patricia McDonald, Timothy J Garrett, Robert J Gillies.
      Malignant tumors exhibit altered metabolism resulting in a highly acidic extracellular microenvironment. Here, we show that cytoplasmic lipid droplet (LD) accumulation, indicative of a lipogenic phenotype, is a cellular adaption to extracellular acidity. LD marker PLIN2 is strongly associated with poor overall survival in breast cancer patients. Acid-induced LD accumulation is triggered by activation of the acid-sensing G-protein-coupled receptor (GPCR) OGR1, which is expressed highly in breast tumors. OGR1 depletion inhibits acid-induced lipid accumulation, while activation by a synthetic agonist triggers LD formation. Inhibition of OGR1 downstream signaling abrogates the lipogenic phenotype, which can be rescued with OGR1 ectopic expression. OGR1-depleted cells show growth inhibition under acidic growth conditions in vitro and tumor formation in vivo. Isotope tracing shows that the source of lipid precursors is primarily autophagy-derived ketogenic amino acids. OGR1-depleted cells are defective in endoplasmic reticulum stress response and autophagy and hence fail to accumulate LDs affecting survival under acidic stress.
    Keywords:  CP: Cancer; ER stress; OGR1/GPR68; acid-sensing GPCR; acidosis; adiposomes; autophagy; lipid droplets; lipid metabolism; lipogenesis; metabolic adaptation
    DOI:  https://doi.org/10.1016/j.celrep.2022.110796
  26. FASEB J. 2022 May;36 Suppl 1
    Inhibition of Anaplerosis Prevented Mitochondrial Dysfunction and Vascular Remodeling in Pulmonary Hypertension.
    Mathews Valuparampil Varghese, Joel James, Maki Niihori, Olga Rafikova, Ruslan Rafikov.
      INTRODUCTION: Pulmonary hypertension (PH) is a deadly disease of the lung vasculature. Recent studies reported mitochondrial dysfunction as a significant contributor to PH pathobiology, the prominent type of dysfunction is still unclear. Importantly, partial mitochondrial functioning is necessary to provide the metabolic intermediates for the proliferative growth of vascular cells in PH. Recently, we reported that in PH, the mitochondrial anabolic branch of metabolism - anaplerosis plays a critical role in the upregulation of the tricarboxylic acid cycle in pulmonary vascular cells with mitochondrial dysfunction.HYPOTHESIS: We hypothesize that the inhibition of both anaplerosis targets - pyruvate carboxylase (PC) and glutaminolysis - glutamate dehydrogenase 1 (GLUD1) in the early stages of PH could effectively attenuate mitochondrial dysfunction and vascular remodeling.
    METHODS: PH was induced in female Sprague Dawley rats by subcutaneous injection of sugen (50 mg/kg)/hypoxia (10% O2 ). The treatment groups received sugen/hypoxia (Su/Hx) and two-weeks intraperitoneal injection of inhibitors (PC inhibitor, phenylacetic acid (PAA), 20 mg/kg/every other day and R162, an inhibitor of GLUD1 (30mg/kg/daily).
    RESULTS: Hemodynamic analysis of five weeks of Su/Hx rats showed a progressive PH phenotype with increased right ventricular (RV) systolic pressure (111.08 ± 6.87 mmHg). Inhibiting anaplerosis at early stages of PH (2 weeks Su/Hx), decreased the RV hypertrophy (0.5 ± 0.02 to 0.42 ± 0.02, p<0.05), RV systolic pressure (71.88 ± 3.59 mmHg to 54.14 ± 2.48 mmHg, p<0.05), and Max dP/dt (3863.89 ± 180.27 mmHg/s to 2890.63 ± 154.52 mmHg/s, p<0.01). Su/Hx group showed an increased glycolytic flux with hexokinase-I upregulation (p<0.05), leading to an upregulation of anaplerosis. This was followed by the impairment in mitochondrial function with a reduction of pyruvate dehydrogenase (PDH) expression (p<0.001) and activation of mitochondrial glycerol-3-phosphate-dehydrogenase (GPD2) (p<0.001), an important mediator of the glycerophosphate shuttle. The increased glycolysis also fluxed into the pentose phosphate pathway (PPP) through myo-inositol oxygenase (MIOX) (p<0.001), a novel source of reactive oxygen species (ROS) generation in PH. These metabolic alterations lead to the upregulation of proliferative signaling pathways Akt (p<0.01), STAT3 (p<0.001), and P38 (p<0.01). Importantly, the inhibition of the anaplerotic pathways by combination (PAA+R162) treatment in the Su/Hx PH model significantly resolved the activation of PPP, restored mitochondrial metabolism, and prevented the proliferative signaling leading to lung vascular remodeling.
    CONCLUSION: The results suggest that inhibition of the anaplerotic pathway effectively attenuated mitochondrial dysfunction and vascular remodeling in Su/HX animals. Therefore, our findings indicate that simultaneous targeting of both PC and glutamine-mediated anaplerosis is a promising therapeutic target for the resolution of vascular remodeling in PH.
    DOI:  https://doi.org/10.1096/fasebj.2022.36.S1.R4126
  27. Life Sci. 2022 May 08. pii: S0024-3205(22)00321-6. [Epub ahead of print] 120621
    Fatty acid binding protein 5 regulates lipogenesis and tumor growth in lung adenocarcinoma.
    Karina Andrea Garcia, María Lucía Costa, Ezequiel Lacunza, María Elizabeth Martinez, Betina Corsico, Natalia Scaglia.
      AIMS: Lung cancer is the leading cause of cancer-related death. Unfortunately, targeted-therapies have been unsuccessful for most patients with lung adenocarcinoma (LUAD). Thus, new early biomarkers and treatment options are a pressing need. Fatty acid binding protein 5 (FABP5) has been associated with various types of cancers. Its contribution to LUAD onset, progression and metabolic reprogramming is, however, not fully understood. In this study we assessed the importance of FABP5 in LUAD and its role in cancer lipid metabolism.MAIN METHODS: By radioactive labeling and metabolite quantification, we studied the function of FABP5 in fatty acid metabolism using genetic/pharmacologic inhibition and overexpression models in LUAD cell lines. Flow cytometry, heterologous transplantation and bioinformatic analysis were used, in combination with other methodologies, to assess the importance of FABP5 for cellular proliferation in vitro and in vivo and in patient survival.
    KEY FINDINGS: We show that high expression of FABP5 is associated with poor prognosis in patients with LUAD. FABP5 regulates lipid metabolism, diverting fatty acids towards complex lipid synthesis, whereas it does not affect their catabolism in vitro. Moreover, FABP5 is required for de novo fatty acid synthesis and regulates the expression of enzymes involved in the pathway (including FASN and SCD1). Consistently with the changes in lipid metabolism, FABP5 is required for cell cycle progression, migration and in vivo tumor growth.
    SIGNIFICANCE: Our results suggest that FABP5 is a regulatory hub of lipid metabolism and tumor progression in LUAD, placing it as a new putative therapeutic target for this disease.
    Keywords:  FABP5; Fatty acid biosynthesis; Lipogenesis; Lung cancer; Metabolism
    DOI:  https://doi.org/10.1016/j.lfs.2022.120621
  28. Cells. 2022 Apr 25. pii: 1454. [Epub ahead of print]11(9):
    How CAR T Cells Breathe.
    Christopher Forcados, Sandy Joaquina, Nicholas Paul Casey, Benjamin Caulier, Sébastien Wälchli.
      The manufacture of efficacious CAR T cells represents a major challenge in cellular therapy. An important aspect of their quality concerns energy production and consumption, known as metabolism. T cells tend to adopt diverse metabolic profiles depending on their differentiation state and their stimulation level. It is therefore expected that the introduction of a synthetic molecule such as CAR, activating endogenous signaling pathways, will affect metabolism. In addition, upon patient treatment, the tumor microenvironment might influence the CAR T cell metabolism by compromising the energy resources. The access to novel technology with higher throughput and reduced cost has led to an increased interest in studying metabolism. Indeed, methods to quantify glycolysis and mitochondrial respiration have been available for decades but were rarely applied in the context of CAR T cell therapy before the release of the Seahorse XF apparatus. The present review will focus on the use of this instrument in the context of studies describing the impact of CAR on T cell metabolism and the strategies to render of CAR T cells more metabolically fit.
    Keywords:  CAR; T cells; chimeric antigen receptor; metabolism; tonic signaling
    DOI:  https://doi.org/10.3390/cells11091454
  29. Metabolism. 2022 May 10. pii: S0026-0495(22)00092-0. [Epub ahead of print] 155214
    Glycerol's contribution to lactate production outside of a glucose intermediate in fasting humans.
    Ankit Shah, Yujue Wang, Xiaoyang Su, Fredric E Wondisford.
      BACKGROUND: Glycerol is a well-recognized substrate for new glucose production via gluconeogenesis in the liver. However, its carbon contribution to the glycolytic intermediate lactate is not known in humans.METHODS: Here we infused stable isotope tracers 13C3-glycerol and 6,6-D2-glucose into six metabolically healthy individuals after an overnight fast to study glycerol metabolism and measure glucose rate of appearance. Serum samples underwent liquid chromatography-mass spectrometry analysis.
    RESULTS: Glycerol and glucose rates of appearance were 2.21 ± 1.42 μmol/kg/min and 7.81 ± 1.15 μmol/kg/min, respectively. Under steady-state conditions, the 13C enrichment for lactate was significantly higher than that of glucose (2.90 ± 0.52% versus 1.53 ± 0.78%, p = 0.017), suggesting direct glycerol to lactate metabolism. The percentage of lactate derived from glycerol was also significantly higher than the percentage of glucose (13.88 ± 2.69% versus 6.50 ± 2.59%, p = 0.005).
    CONCLUSION: Given that lactate itself is a carbon source for gluconeogenesis and tricycarboxylic cycle intermediates, glycerol's ability to donate carbons to lactate may make it quantitatively more important to intermediary metabolism than currently appreciated.
    Keywords:  Carbon flux; Gluconeogenesis; Glycerol; Lactate; Mass spectrometry
    DOI:  https://doi.org/10.1016/j.metabol.2022.155214
  30. FASEB J. 2022 May;36 Suppl 1
    Phosphoglycerate Mutase 5 Expression Modulates Hepatocellular Steatosis.
    Andrea Johnston, Cambri Moeller, Chin-Chi Liu.
      Phosphoglycerate Mutase 5 (PGAM5) is a serine/threonine phosphatase that plays a role in oxidant injury sensing, mitochondrial biogenesis, mitophagy, and multiple cell death pathways. Pgam5 null mice are protected from high-fat diet induced obesity. This metabolic phenotype was attributed to upregulation of adaptive thermogenesis in brown adipose tissue, but hepatocyte specific lipid metabolism has not been evaluated. We hypothesize that hepatic PGAM5 expression level modulates hepatic steatosis. Using primary cultures of Pgam5 knockout hepatocytes, we have shown that palmitate induced steatosis is attenuated and that treatment with the long-chain fatty acid impairs oxygen consumption rate specifically reducing the maximal respiratory capacity. Further, over-expression of PGAM5 in human hepatoma cells exacerbates palmitate induced steatosis. Cumulatively, these results suggest that PGAM5 regulates hepatic lipogenesis and mitochondrial long-chain fatty acid beta-oxidation.
    DOI:  https://doi.org/10.1096/fasebj.2022.36.S1.R3988
  31. Mol Biol Cell. 2022 May 11. mbcE22020066
    The short-chain fatty acid acetate modulates epithelial-to-mesenchymal transition.
    Junfang Lyu, Mehdi Pirooznia, Yuesheng Li, Jianhua Xiong.
      Normal tissue and organ morphogenesis requires epithelial cell plasticity and conversion to a mesenchymal phenotype through a tightly regulated process: epithelial-to-mesenchymal transition (EMT). Alterations of EMT go far beyond cell-lineage segregation and contribute to pathologic conditions such as cancer. EMT is subject to intersecting control pathways; however, EMT's metabolic mechanism remains poorly understood. Here, we demonstrate that transforming growth factor β (TGF-β)-induced EMT is accompanied by decreased fatty acid oxidation (FAO) and reduced acetyl-coenzyme A (acetyl-CoA) levels. Acetyl-CoA is a central metabolite and the sole donor of acetyl groups to acetylate key proteins. Further, the short-chain fatty acid acetate increases acetyl-CoA levels-robustly inhibiting EMT and cancer cell migration. Acetate can restore EMT-associated α-tubulin acetylation levels, increasing microtubule stability. Transcriptome profiling and flow cytometric analysis show that acetate inhibits the global gene expression program associated with EMT and the EMT-associated G1 cell cycle arrest. Taken together, these results demonstrate that acetate is a potent metabolic regulator of EMT and that therapeutic manipulation of acetate metabolism could provide the basis for treating a wide range of EMT-linked pathological conditions, including cancer.
    DOI:  https://doi.org/10.1091/mbc.E22-02-0066
  32. J Lipid Res. 2022 May 07. pii: S0022-2275(22)00056-6. [Epub ahead of print] 100223
    Isomeric lipid signatures reveal compartmentalized fatty acid metabolism in cancer.
    Reuben S E Young, Andrew P Bowman, Kaylyn D Tousignant, Berwyck L J Poad, Jennifer H Gunter, Lisa K Philp, Colleen C Nelson, Shane R Ellis, Ron M A Heeren, Martin C Sadowski, Stephen J Blanksby.
      The cellular energy and biomass demands of cancer drive a complex dynamic between uptake of extracellular fatty acids (FA) and their de novo synthesis. Given that oxidation of de novo synthesized FAs for energy would result in net-energy loss, there is an implication that FAs from these two sources must have distinct metabolic fates; however, hitherto all FAs have been considered part of a common pool. To probe potential metabolic partitioning of cellular FAs, cancer cells were supplemented with stable isotope-labeled FAs. Structural analysis of the resulting glycerophospholipids revealed that labeled FAs from uptake were largely incorporated to canonical (sn-) positions on the glycerol backbone. Surprisingly, labelled FA uptake also disrupted canonical isomer patterns of the unlabeled lipidome, and induced repartitioning of n-3 and n-6 polyunsaturated FAs into glycerophospholipid classes. These structural changes support the existence of differences in the metabolic fates of FAs derived from uptake or de novo sources and demonstrate unique signaling and remodeling behaviors usually hidden from conventional lipidomics.
    Keywords:  Fatty acid/Transport; Imaging Mass Spectrometry; Lipase; Lipid Isomers; Lipolysis and fatty acid metabolism; Ozone-Induced Dissociation; Phospholipid/Metabolism; Phospholipids/Phosphatidylcholine; Stable-Isotope Tracing
    DOI:  https://doi.org/10.1016/j.jlr.2022.100223
  33. J Exp Med. 2022 Jul 04. pii: e20211948. [Epub ahead of print]219(7):
    Role of adipose tissue macrophages in obesity-related disorders.
    Svetoslav Chakarov, Camille Blériot, Florent Ginhoux.
      The obesity epidemic has led researchers and clinicians to reconsider the etiology of this disease and precisely decipher its molecular mechanisms. The excessive accumulation of fat by cells, most notably adipocytes, which play a key role in this process, has many repercussions in tissue physiology. Herein, we focus on how macrophages, immune cells well known for their tissue gatekeeping functions, assume fundamental, yet ill-defined, roles in the genesis and development of obesity-related metabolic disorders. We first discuss the determinants of the biology of these cells before introducing the specifics of the adipose tissue environment, while highlighting its heterogeneity. Finally, we detail how obesity transforms both adipose tissue and local macrophage populations. Understanding macrophage diversity and their cross talk with the diverse cell types constituting the adipose tissue environment will allow us to frame the therapeutic potential of adipose tissue macrophages in obesity.
    DOI:  https://doi.org/10.1084/jem.20211948
  34. Oncoimmunology. 2022 ;11(1): 2070337
    Overcoming T cell dysfunction in acidic pH to enhance adoptive T cell transfer immunotherapy.
    Flor Navarro, Noelia Casares, Celia Martín-Otal, Aritz Lasarte-Cía, Marta Gorraiz, Patricia Sarrión, Diana Llopiz, David Reparaz, Nerea Varo, Juan Roberto Rodriguez-Madoz, Felipe Prosper, Sandra Hervás-Stubbs, Teresa Lozano, Juan José Lasarte.
      The high metabolic activity and insufficient perfusion of tumors leads to the acidification of the tumor microenvironment (TME) that may inhibit the antitumor T cell activity. We found that pharmacological inhibition of the acid loader chloride/bicarbonate anion exchanger 2 (Ae2), with 4,4'-diisothiocyanatostilbene-2,2'-disulfonicacid (DIDS) enhancedCD4+ andCD8+ T cell function upon TCR activation in vitro, especially under low pH conditions. In vivo, DIDS administration delayed B16OVA tumor growth in immunocompetent mice as monotherapy or when combined with adoptive T cell transfer of OVA-specificT cells. Notably, genetic Ae2 silencing in OVA-specificT cells improvedCD4+/CD8+ T cell function in vitro as well as their antitumor activity in vivo. Similarly, genetic modification of OVA-specificT cells to overexpress Hvcn1, a selectiveH+ outward current mediator that prevents cell acidification, significantly improved T cell function in vitro, even at low pH conditions. The adoptive transfer of OVA-specificT cells overexpressing Hvcn1 exerted a better antitumor activity in B16OVA tumor-bearingmice. Hvcn1 overexpression also improved the antitumor activity of CAR T cells specific for Glypican 3 (GPC3) in mice bearing PM299L-GPC3tumors. Our results suggest that preventing intracellular acidification by regulating the expression of acidifier ion channels such as Ae2 or alkalinizer channels like Hvcn1 in tumor-specificlymphocytes enhances their antitumor response by making them more resistant to the acidic TME.
    Keywords:  AE2; HVCN1; Lymphocytes; adoptive cell therapy; intracellular pH; tumor microenvironment
    DOI:  https://doi.org/10.1080/2162402X.2022.2070337
  35. Int Immunopharmacol. 2022 May 10. pii: S1567-5769(22)00301-0. [Epub ahead of print]109 108817
    LAT1-specific inhibitor ameliorates severe autoimmune arthritis in SKG mouse.
    Takayoshi Owada, Kazuhiro Kurasawa, Hitoshi Endou, Tomoe Fujita, Naohiko Anzai, Keitaro Hayashi.
      L-type amino acid transporter 1 (LAT1, slc7a5) supplies large neutral amino acids to highly proliferative cells. LAT1 is an attractive therapeutic target for treating overactive T cell-mediated immune disorders due to its high expression in activated T cells, but not in resting T cells. Here, we demonstrate that LAT1 plays a crucial role in T helper (Th) 17-mediated autoimmune arthritis in SKG mice, an animal model of human rheumatoid arthritis (RA). Administration of JPH203, a LAT1-specific inhibitor, suppressed mannan-induced joint swelling, synoviocyte proliferation and inflammatory cell infiltration in SKG mice. A diminished metabolic reprogramming, including a decrease in oxidative phosphorylation that regulates Hif-1α expression and subsequent control of glycolysis enzymes, was involved in the downregulation of Th17 differentiation by LAT1 inhibition. Moreover, publicly released database analysis revealed facilitated expression of LAT1 in T cells with cytotoxic features in patients with RA. Our results demonstrate the essential contribution of LAT1 to the development of RA, proposing a potential therapeutic approach targeting amino acid transporters for treating hypersensitive immune diseases.
    Keywords:  JPH203; L-type amino acid transporter (LAT) 1; Rheumatoid arthritis; T helper (Th) 17
    DOI:  https://doi.org/10.1016/j.intimp.2022.108817
  36. Cancer Treat Res. 2022 ;183 275-285
    The Single-Cell Level Perspective of the Tumor Microenvironment and Its Remodeling by CAR-T Cells.
    Sanxing Gao, Ryohichi Sugimura.
      The tumor microenvironment (TME) is a complex milieu consisting of lymphoid cells, myeloid cells, fibroblasts, and multiple molecules, which play a key role in tumor progression and immunotherapy. TME is characterized by immune-suppressive features, which release anti-inflammatory cytokines such as IL-4 and TGFβ to skew the T cells to a Th2 state as well to polarize tumor-associated macrophages (TAMs) to an anti-inflammatory phenotype to curb the immunotherapy. Considering the heterogeneity of the TME and its role in determining response to chimeric antigen receptor (CAR)-T cells, delineating TME at a single-cell level will provide useful information for cancer treatment. First, we discuss cellular and molecular features that curb the response to CAR-T cells, for example, high expression of immune checkpoint molecules (PD-1, LAG3) and anti-inflammatory cytokines (IL-4, TGFb) that block CAR-T cell function. Then, we summarize how newly invented single-cell technologies such as spatial multi-omics would benefit the understanding of cancer immunotherapy. Finally, we will further describe recent attempts of CAR-T to remodel TME by arming the CAR-T with anti-PD-1 single-chain variants or Th1 triggering cytokines (such as IL-7, IL-12) to remodel TME into a pro-inflammatory state. Herein, we review the single-cell-level signatures of TME and the strategies of CAR-T to remodel TME.
    DOI:  https://doi.org/10.1007/978-3-030-96376-7_10
  37. Clin Exp Immunol. 2022 May 10. pii: uxac048. [Epub ahead of print]
    Dendritic Cells metabolism - a strategic path to improve antitumoral DC vaccination.
    Emma Currivan, David Finlay, Diana Moreira.
      
    Keywords:  Dendritic cells; Metabolism; antitumour immunity; vaccines
    DOI:  https://doi.org/10.1093/cei/uxac048
  38. Antioxid Redox Signal. 2022 May 11.
    Role of Metabolism in Adoptive T Cell Therapy: Strategies and Challenges.
    Ge Hui Tan, Carmen Chak-Lui Wong.
      SIGNIFICANCE: Immune cell therapy, involves the administration of immune cells into patients, has emerged as one of the most common type of immunotherapy for cancer treatment. Knowledge on the biology and metabolism of the adoptively transferred immune cells and the metabolic requirements of different cell types in the tumour is fundamental for the development of immune cell therapy with higher efficacy.RECENT ADVANCES: Adoptive T cell therapy has shown to be effective in limited types of cancer. Different types and generations of adoptive T cell therapies have evolved in the recent decade. This review covers the basic principles and development of these therapies in cancer treatment.
    CRITICAL ISSUES: Our review provides an overview on the basic concepts on T cell metabolism and highlights the metabolic requirements of T and adoptively transferred T cells.
    FUTURE DIRECTIONS: Integrating the knowledge above will facilitate the development of strategies to maximize the expansion of adoptively transferred T cells ex vivo and in vivo and promote their durability and anti-tumour effects.
    DOI:  https://doi.org/10.1089/ars.2022.0037
  39. FASEB J. 2022 May;36 Suppl 1
    Targeting GCN2 Regulation of Amino Acid Homeostasis in Prostate Cancer.
    Ricardo Cordova, Jagannath Misra, Parth H Amin, Nur P Damayanti, Kenneth R Carlson, Angela J Klunk, Emily T Mirek, Marcus J Miller, Tracy G Anthony, Roberto Pili, Ronald C Wek, Kirk A Staschke.
      The Integrated Stress Response (ISR) plays a critical role in the adaptation and survival of tumor cells to exogenous and endogenous stresses. The ISR features four protein kinases (PERK, GCN2, PKR, and HRI), each activated by different stresses, that phosphorylate the eukaryotic translation initiation factor eIF2, resulting in repression of global protein synthesis. Paradoxically, eIF2 phosphorylation also enhances translation of select gene transcripts, including the transcription factor ATF4, which is central for ISR-directed gene transcription. Therefore, the ISR directs translational and transcriptional control that is critical for cancer stress adaptation. Moreover, eIF2 phosphorylation and ATF4 have recently been suggested to play a role in prostate cancer (PCa) growth and survival; however, the specific function of ISR kinases, their mode of activation, and the mechanisms by which the ISR facilitate PCa progression are unknown. We discovered that GCN2 is activated in a range of PCa cell lines, contributing to enhanced eIF2 phosphorylation and ATF4 expression. Genetic or pharmacological inhibition of GCN2 reduces growth in androgen-sensitive and castration-resistant PCa cell lines in culture and cell line-derived and patient-derived xenograft mouse models in vivo. Induction of GCN2 is accompanied by limitations of select amino acids and accumulation of cognate tRNAs that are reported to be activators of GCN2. A transcriptome analysis of PCa cells treated with a specific GCN2 small molecular inhibitor indicates that GCN2 is critical for expression of SLCgenes involved in metabolite transport. We found that GCN2 inhibition decreases intracellular amino acid levels accounting for reduced growth in PCa cells. Using CRISPR-based phenotypic screens and genome-wide gene expression analyses of wild-type and GCN2-depleted PCa cells, we confirmed the importance of the transporter genes in PCa fitness. One transporter, SLC3A2 (4F2), is induced by GCN2 and is essential for PCa proliferation. SLC3A2 engages with many nutrient transporters, allowing for their localization to the plasma membrane. Importantly, expression of SLC3A2 reduced GCN2 activation and rescued decreased amino acid levels and growth inhibition due to loss of GCN2. Our results indicate that select amino acid limitations activate GCN2 in PCa, resulting in the upregulation of key amino acid transporters, including 4F2 (SLC3A2), which provide for nutrient import to facilitate protein synthesis and metabolism required for PCa progression. We conclude that GCN2 and the ISR are promising therapeutic targets for both androgen-sensitive and castration-resistant prostate cancer.
    DOI:  https://doi.org/10.1096/fasebj.2022.36.S1.0R314
  40. J Inherit Metab Dis. 2022 May 11.
    Application of Metabolite Set Enrichment Analysis (MSEA) on untargeted metabolomics data prioritizes relevant pathways and detects novel biomarkers for inherited metabolic disorders.
    Brechtje Hoegen, Juliet E Hampstead, Udo F Engelke, Purva Kulkarni, Ron A Wevers, Han G Brunner, Karlien L M Coene, Christian Gilissen.
      Untargeted metabolomics (UM) allows for the simultaneous measurement of hundreds of metabolites in a single analytical run. The sheer amount of data generated in UM hampers its use in patient diagnostics because manual interpretation of all features is not feasible. Here, we describe the application of a pathway-based metabolite set enrichment analysis method (MSEA) to prioritise relevant biological pathways in UM data. We validate our method on a set of 55 patient samples with a diagnosed inherited metabolic disorder (IMD), and show that it complements feature-based prioritisation of biomarkers by placing the features in a biological context. In addition, we find that by taking enriched pathways shared across different IMDs we can identify common drugs and compounds that could otherwise obscure genuine disease biomarkers in an enrichment method. Finally, we demonstrate the potential of this method to identify novel candidate biomarkers for known IMDs. Our results show the added value of pathway-based interpretation of UM data in IMD diagnostics context.
    Keywords:  Biochemical pathways; Biomarkers; Cystathionine ß-synthase; Inborn errors of metabolism; Inherited metabolic disorders; Mass spectrometry; Metabolite set enrichment analysis; Next generation metabolic screening; Untargeted metabolomics
    DOI:  https://doi.org/10.1002/jimd.12522
  41. Clin Exp Immunol. 2022 May 13. 208(1): 83-94
    Differentiation of circulating monocytes into macrophages with metabolically activated phenotype regulates inflammation in dyslipidemia patients.
    Elena Berenice Martínez-Shio, Ángel Martín Cárdenas-Hernández, Verónica Jiménez-Suárez, Laura Sherell Marín-Jáuregui, Claudia Castillo-Martin Del Campo, Roberto González-Amaro, Carlos D Escobedo-Uribe, Adriana Elizabeth Monsiváis-Urenda.
      Macrophages are mediators of inflammation having an important role in the pathogenesis of cardiovascular diseases. Recently, a pro-inflammatory subpopulation, known as metabolically activated macrophages (MMe), has been described in conditions of obesity and metabolic syndrome where they are known to release cytokines that can promote insulin resistance. Dyslipidemia represents an important feature in metabolic syndrome and corresponds to one of the main modifiable risk factors for the development of cardiovascular diseases. Circulating monocytes can differentiate into macrophages under certain conditions. They correspond to a heterogeneous population, which include inflammatory and anti-inflammatory subsets; however, there is a wide spectrum of phenotypes. Therefore, we decided to investigate whether the metabolic activated monocyte (MoMe) subpopulation is already present under dyslipidemia conditions. Secondly, we assessed whether different levels of cholesterol and triglycerides play a role in the polarization towards the metabolic phenotype (MMe) of macrophages. Our results indicate that MoMe cells are found in both healthy and dyslipidemia patients, with cells displaying the following metabolic phenotype: CD14varCD36+ABCA1+PLIN2+. Furthermore, the percentages of CD14++CD68+CD80+ pro-inflammatory monocytes are higher in dyslipidemia than in healthy subjects. When analysing macrophage differentiation, we observed that MMe percentages were higher in the dyslipidemia group than in healthy subjects. These MMe have the ability to produce high levels of IL-6 and the anti-inflammatory cytokine IL-10. Furthermore, ABCA1 expression in MMe correlates with LDL serum levels. Our study highlights the dynamic contributions of metabolically activated macrophages in dyslipidemia, which may have a complex participation in low-grade inflammation due to their pro- and anti-inflammatory function.
    Keywords:  Metabolically activated macrophages; dyslipidemia; immune regulation; interleukin-10 (IL-10); monocytes
    DOI:  https://doi.org/10.1093/cei/uxac013
  42. Endocrinology. 2022 May 10. pii: bqac062. [Epub ahead of print]
    Paracrine regulation of adipose tissue macrophages by their neighbors in the micro-environment of obese adipose tissue.
    Kai Wang, Yuan-Yuan Wang, Liang-Liang Wu, Li-Yan Jiang, Yin Hu, Xin-Hua Xiao, Ya-Di Wang.
      Obesity has recently been defined as a chronic low-grade inflammatory disease. Obesity-induced inflammation of adipose tissue (AT) is an essential trigger for insulin resistance (IR) and related metabolic diseases. Although the underlying molecular basis of this inflammation has not been fully identified, there is consensus that the recruited and activated macrophages in AT are the most important culprits of AT chronic inflammation. Adipose tissue macrophages (ATMs) are highly plastic and could be polarized from an anti-inflammatory M2 to pro-inflammatory M1 phenotypes upon stimulation by micro-environmental signals from obese AT. Many efforts have been made to elucidate the molecular signaling pathways of macrophage polarization, however, the upstream drivers governing and activating macrophage polarization have rarely been summarized, particularly regulatory messages from the AT micro-environment. In addition to adipocytes, the AT bed also contains a variety of immune cells, stem cells, as well as vascular, neural and lymphatic tissues throughout, which together orchestrate the AT micro-environment. Here, we summarized how the aforesaid neighbors of ATMs in the AT micro-environment send messages to ATMs and thus regulate its phenotype during obesity. Deciphering the biology and polarization of ATMs in the obese environment is expected to provide a precise immunotherapy for adipose inflammation and obesity-related metabolic diseases.
    Keywords:  adipose tissue macrophages (ATMs); adipose tissue micro-environment; macrophage polarization; obesity; paracrine
    DOI:  https://doi.org/10.1210/endocr/bqac062
  43. Hepatology. 2022 May 14.
    Multiomics identifies the link between intratumor steatosis and the exhausted tumor immune microenvironment in hepatocellular carcinoma.
    Hiroki Murai, Takahiro Kodama, Kazuki Maesaka, Shoichiro Tange, Daisuke Motooka, Yutaka Suzuki, Yasuyuki Shigematsu, Kentaro Inamura, Yoshihiro Mise, Akio Saiura, Yoshihiro Ono, Yu Takahashi, Yota Kawasaki, Satoshi Iino, Shogo Kobayashi, Masashi Idogawa, Takashi Tokino, Tomomi Hashidate-Yoshida, Hideo Shindou, Masanori Miyazaki, Yasuharu Imai, Satoshi Tanaka, Eiji Mita, Kazuyoshi Ohkawa, Hayato Hikita, Ryotaro Sakamori, Tomohide Tatsumi, Hidetoshi Eguchi, Eiichi Morii, Tetsuo Takehara.
      BACKGROUND&AIMS: Immunotherapy has become the standard-of-care treatment for hepatocellular carcinoma (HCC), but its efficacy remains limited. To identify immunotherapy-susceptible HCC, we profiled the molecular abnormalities and tumor immune microenvironment (TIME) of rapidly increasing nonviral HCC.APPROACHES&RESULTS: We performed RNA-seq of tumor tissues in 113 nonviral HCC patients and cancer genome sequencing of 69 genes with recurrent genetic alterations reported in HCC. Unsupervised hierarchical clustering classified nonviral HCCs into 3 molecular classes (Class I, II, III), which stratified patient prognosis. Class I, with the poorest prognosis, was associated with TP53 mutations, whereas class III, with the best prognosis, was associated with CTNNB1 mutations. Thirty-eight percent of nonviral HCC was defined as an immune class characterized by a high frequency of intratumoral steatosis and a low frequency of CTNNB1 mutations. Steatotic HCC, which accounts for 23% of nonviral HCC cases, presented an immune-enriched but immune-exhausted TIME characterized by T-cell exhaustion, M2 macrophage and cancer-associated fibroblast (CAF) infiltration, high PD-L1 expression, and TGF-β signaling activation. Spatial transcriptome analysis suggested that M2 macrophages and CAFs may be in close proximity to exhausted CD8+ T cells in steatotic HCC. An in vitro study showed that palmitic acid-induced lipid accumulation in HCC cells upregulated PD-L1 expression and promoted immunosuppressive phenotypes of cocultured macrophages and fibroblasts. Steatotic HCC patients, confirmed by chemical-shift MR imaging, had significantly longer PFS with combined immunotherapy using anti-PD-L1 and anti-VEGF antibodies.
    CONCLUSIONS: Multiomics stratified nonviral HCCs according to prognosis or TIME. We identified the link between intratumoral steatosis and immune-exhausted immunotherapy-susceptible TIME.
    DOI:  https://doi.org/10.1002/hep.32573
  44. Mol Immunol. 2022 May 06. pii: S0161-5890(22)00195-X. [Epub ahead of print]147 101-114
    TBK1 participates in glutaminolysis by mediating the phosphorylation of RIPK3 to promote endotoxin tolerance.
    Lehan Pan, Lian Yang, Zhujun Yi, Wenfeng Zhang, Jianping Gong.
      TRAF-associated NF-κB activator (TANK)-binding kinase 1 (TBK1), a nonclassical IκB kinase (IKK), and its effect on inflammation have not been entirely clarified. Here, we identified that TBK1 participates in the catabolism of glutamine by mediating the phosphorylation of receptor-interacting protein kinase 3 (RIPK3) and promoting macrophage endotoxin tolerance (ET). We found that the TBK1 protein directly interacts with the RIPK3 protein and mediates the phosphorylation of RIPK3 in macrophages. Activated RIPK3 can directly bind to glutamate dehydrogenase 1 (GLUD1), which is known to be a critical enzyme for catalyzing glutamine decomposition, to improve its catalytic activity and increase the production of α-ketoglutarate (α-KG) in macrophages. α-KG generated from glutaminolysis can promote M2 activation and restrict M1 polarization, which plays a crucial role in promoting lipopolysaccharide (LPS)-induced ET. As a result of TBK1 regulating the phosphorylation level of RIPK3, overexpressed TBK1 could enhance the tolerance of macrophages to endotoxin through glutaminolysis. Overall, these findings reveal a novel mechanism for the metabolic control of inflammation and for the induction of ET by modulating glutamine metabolism.
    Keywords:  Endotoxin tolerance; GLUD1; RIPK3; Sepsis; TBK1; α-KG
    DOI:  https://doi.org/10.1016/j.molimm.2022.04.009
  45. Cell Rep. 2022 May 10. pii: S2211-1247(22)00559-9. [Epub ahead of print]39(6): 110792
    The lactate-NAD+ axis activates cancer-associated fibroblasts by downregulating p62.
    Juan F Linares, Tania Cid-Diaz, Angeles Duran, Marta Osrodek, Anxo Martinez-Ordoñez, Miguel Reina-Campos, Hui-Hsuan Kuo, Olivier Elemento, M Laura Martin, Thekla Cordes, Timothy C Thompson, Christian M Metallo, Jorge Moscat, Maria T Diaz-Meco.
      Reduced p62 levels are associated with the induction of the cancer-associated fibroblast (CAF) phenotype, which promotes tumorigenesis in vitro and in vivo through inflammation and metabolic reprogramming. However, how p62 is downregulated in the stroma fibroblasts by tumor cells to drive CAF activation is an unresolved central issue in the field. Here we show that tumor-secreted lactate downregulates p62 transcriptionally through a mechanism involving reduction of the NAD+/NADH ratio, which impairs poly(ADP-ribose)-polymerase 1 (PARP-1) activity. PARP-1 inhibition blocks the poly(ADP-ribosyl)ation of the AP-1 transcription factors, c-FOS and c-JUN, which is an obligate step for p62 downregulation. Importantly, restoring p62 levels in CAFs by NAD+ renders CAFs less active. PARP inhibitors, such as olaparib, mimick lactate in the reduction of stromal p62 levels, as well as the subsequent stromal activation both in vitro and in vivo, which suggests that therapies using olaparib would benefit from strategies aimed at inhibiting CAF activity.
    Keywords:  AP-1; CP: Cancer; NAD(+)/NADH; PARP inhibitors; SQSTM1; cancer metabolism; cancer-associated fibroblasts; olaparib; p62; poly(ADP-ribose)-polymerase 1; stroma
    DOI:  https://doi.org/10.1016/j.celrep.2022.110792
  46. Cells. 2022 May 04. pii: 1536. [Epub ahead of print]11(9):
    Glycogen Storage Disease Phenotypes Accompanying the Perturbation of the Methionine Cycle in NDRG3-Deficient Mouse Livers.
    Hyun Ahm Sohn, Dong Chul Lee, Anna Park, Minho Kang, Byoung-Ha Yoon, Chul-Ho Lee, Yong-Hoon Kim, Kyoung-Jin Oh, Cha Yeon Kim, Seong-Hwan Park, Han Koo, Hyoung-Chin Kim, Won Kee Yoon, Dae-Sik Lim, Daesoo Kim, Kyung Chan Park, Young Il Yeom.
      N-Myc downstream regulated gene 3 (NDRG3) is a unique pro-tumorigenic member among NDRG family genes, mediating growth signals. Here, we investigated the pathophysiological roles of NDRG3 in relation to cell metabolism by disrupting its functions in liver. Mice with liver-specific KO of NDRG3 (Ndrg3 LKO) exhibited glycogen storage disease (GSD) phenotypes including excessive hepatic glycogen accumulation, hypoglycemia, elevated liver triglyceride content, and several signs of liver injury. They suffered from impaired hepatic glucose homeostasis, due to the suppression of fasting-associated glycogenolysis and gluconeogenesis. Consistently, the expression of glycogen phosphorylase (PYGL) and glucose-6-phosphate transporter (G6PT) was significantly down-regulated in an Ndrg3 LKO-dependent manner. Transcriptomic and metabolomic analyses revealed that NDRG3 depletion significantly perturbed the methionine cycle, redirecting its flux towards branch pathways to upregulate several metabolites known to have hepatoprotective functions. Mechanistically, Ndrg3 LKO-dependent downregulation of glycine N-methyltransferase in the methionine cycle and the resultant elevation of the S-adenosylmethionine level appears to play a critical role in the restructuring of the methionine metabolism, eventually leading to the manifestation of GSD phenotypes in Ndrg3 LKO mice. Our results indicate that NDRG3 is required for the homeostasis of liver cell metabolism upstream of the glucose-glycogen flux and methionine cycle and suggest therapeutic values for regulating NDRG3 in disorders with malfunctions in these pathways.
    Keywords:  GNMT; NDRG3; PYGL; glycogen storage disease; methionine cycle; reprogramming
    DOI:  https://doi.org/10.3390/cells11091536
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