Publications by authors named "Russell G Jones"

89 Publications

Structure of an AMPK complex in an inactive, ATP-bound state.

Science 2021 07;373(6553):413-419

Department of Structural Biology, Van Andel Institute, Grand Rapids, MI 49503, USA.

Adenosine monophosphate (AMP)-activated protein kinase (AMPK) regulates metabolism in response to the cellular energy states. Under energy stress, AMP stabilizes the active AMPK conformation, in which the kinase activation loop (AL) is protected from protein phosphatases, thus keeping the AL in its active, phosphorylated state. At low AMP:ATP (adenosine triphosphate) ratios, ATP inhibits AMPK by increasing AL dynamics and accessibility. We developed conformation-specific antibodies to trap ATP-bound AMPK in a fully inactive, dynamic state and determined its structure at 3.5-angstrom resolution using cryo-electron microscopy. A 180° rotation and 100-angstrom displacement of the kinase domain fully exposes the AL. On the basis of the structure and supporting biophysical data, we propose a multistep mechanism explaining how adenine nucleotides and pharmacological agonists modulate AMPK activity by altering AL phosphorylation and accessibility.
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http://dx.doi.org/10.1126/science.abe7565DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8428800PMC
July 2021

Interrogating in vivo T-cell metabolism in mice using stable isotope labeling metabolomics and rapid cell sorting.

Nat Protoc 2021 09 4;16(9):4494-4521. Epub 2021 Aug 4.

Department of Metabolism and Nutritional Programming, Van Andel Institute, Grand Rapids, MI, USA.

T cells are integral players in the adaptive immune system that readily adapt their metabolism to meet their energetic and biosynthetic needs. A major hurdle to understand physiologic T-cell metabolism has been the differences between in vitro cell culture conditions and the complex in vivo milieu. To address this, we have developed a protocol that merges traditional immunology infection models with whole-body metabolite infusion and mass-spectrometry-based metabolomic profiling to assess T-cell metabolism in vivo. In this protocol, pathogen-infected mice are infused via the tail vein with an isotopically labeled metabolite (2-6 h), followed by rapid magnetic bead isolation to purify T-cell populations (<1 h) and then stable isotope labeling analysis conducted by mass spectrometry (~1-2 d). This procedure enables researchers to evaluate metabolic substrate utilization into central carbon metabolic pathways (i.e., glycolysis and the tricarboxylic acid cycle) by specific T-cell subpopulations in the context of physiological immune responses in vivo.
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http://dx.doi.org/10.1038/s41596-021-00586-2DOI Listing
September 2021

Itaconate confers tolerance to late NLRP3 inflammasome activation.

Cell Rep 2021 03;34(10):108756

Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA. Electronic address:

Itaconate is a unique regulatory metabolite that is induced upon Toll-like receptor (TLR) stimulation in myeloid cells. Here, we demonstrate major inflammatory tolerance and cell death phenotypes associated with itaconate production in activated macrophages. We show that endogenous itaconate is a key regulator of the signal 2 of NLR family pyrin domain containing 3 (NLRP3) inflammasome activation after long lipopolysaccharide (LPS) priming, which establishes tolerance to late NLRP3 inflammasome activation. We show that itaconate acts synergistically with inducible nitric oxide synthase (iNOS) and that the ability of various TLR ligands to establish NLRP3 inflammasome tolerance depends on the pattern of co-expression of IRG1 and iNOS. Mechanistically, itaconate accumulation upon prolonged inflammatory stimulation prevents full caspase-1 activation and processing of gasdermin D, which we demonstrate to be post-translationally modified by endogenous itaconate. Altogether, our data demonstrate that metabolic rewiring in inflammatory macrophages establishes tolerance to NLRP3 inflammasome activation that, if uncontrolled, can result in pyroptotic cell death and tissue damage.
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http://dx.doi.org/10.1016/j.celrep.2021.108756DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8039864PMC
March 2021

1-Methylnicotinamide is an immune regulatory metabolite in human ovarian cancer.

Sci Adv 2021 Jan 20;7(4). Epub 2021 Jan 20.

Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada.

Immune regulatory metabolites are key features of the tumor microenvironment (TME), yet with a few exceptions, their identities remain largely unknown. Here, we profiled tumor and T cells from tumor and ascites of patients with high-grade serous carcinoma (HGSC) to uncover the metabolomes of these distinct TME compartments. Cells within the ascites and tumor had pervasive metabolite differences, with a notable enrichment in 1-methylnicotinamide (MNA) in T cells infiltrating the tumor compared with ascites. Despite the elevated levels of MNA in T cells, the expression of nicotinamide -methyltransferase, the enzyme that catalyzes the transfer of a methyl group from -adenosylmethionine to nicotinamide, was restricted to fibroblasts and tumor cells. Functionally, MNA induces T cells to secrete the tumor-promoting cytokine tumor necrosis factor alpha. Thus, TME-derived MNA contributes to the immune modulation of T cells and represents a potential immunotherapy target to treat human cancer.
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http://dx.doi.org/10.1126/sciadv.abe1174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7817098PMC
January 2021

Immunometabolic Interplay in the Tumor Microenvironment.

Cancer Cell 2021 01 29;39(1):28-37. Epub 2020 Oct 29.

Metabolic and Nutritional Programming, Center for Cancer and Cell Biology, Van Andel Institute, Grand Rapids, MI 49503, USA. Electronic address:

Immune cells' metabolism influences their differentiation and function. Given that a complex interplay of environmental factors within the tumor microenvironment (TME) can have a profound impact on the metabolic activities of immune, stromal, and tumor cell types, there is emerging interest to advance understanding of these diverse metabolic phenotypes in the TME. Here, we discuss cell-extrinsic contributions to the metabolic activities of immune cells. Then, considering recent technical advances in experimental systems and metabolic profiling technologies, we propose future directions to better understand how immune cells meet their metabolic demands in the TME, which can be leveraged for therapeutic benefit.
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http://dx.doi.org/10.1016/j.ccell.2020.09.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7837268PMC
January 2021

Memory CD8 T Cells Balance Pro- and Anti-inflammatory Activity by Reprogramming Cellular Acetate Handling at Sites of Infection.

Cell Metab 2020 09 31;32(3):457-467.e5. Epub 2020 Jul 31.

Department of Biomedicine, Immunobiology, University of Basel, 4031 Basel, Switzerland; Department of Medicine, CITIID, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge CB2 0AW, UK. Electronic address:

Serum acetate increases upon systemic infection. Acutely, assimilation of acetate expands the capacity of memory CD8 T cells to produce IFN-γ. Whether acetate modulates memory CD8 T cell metabolism and function during pathogen re-encounter remains unexplored. Here we show that at sites of infection, high acetate concentrations are being reached, yet memory CD8 T cells shut down the acetate assimilating enzymes ACSS1 and ACSS2. Acetate, being thus largely excluded from incorporation into cellular metabolic pathways, now had different effects, namely (1) directly activating glutaminase, thereby augmenting glutaminolysis, cellular respiration, and survival, and (2) suppressing TCR-triggered calcium flux, and consequently cell activation and effector cell function. In vivo, high acetate abundance at sites of infection improved pathogen clearance while reducing immunopathology. This indicates that, during different stages of the immune response, the same metabolite-acetate-induces distinct immunometabolic programs within the same cell type.
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http://dx.doi.org/10.1016/j.cmet.2020.07.004DOI Listing
September 2020

Glucose-dependent partitioning of arginine to the urea cycle protects β-cells from inflammation.

Nat Metab 2020 05 11;2(5):432-446. Epub 2020 May 11.

Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.

Chronic inflammation is linked to diverse disease processes, but the intrinsic mechanisms that determine cellular sensitivity to inflammation are incompletely understood. Here, we show the contribution of glucose metabolism to inflammation-induced changes in the survival of pancreatic islet β-cells. Using metabolomic, biochemical and functional analyses, we investigate the protective versus non-protective effects of glucose in the presence of pro-inflammatory cytokines. When protective, glucose metabolism augments anaplerotic input into the TCA cycle via pyruvate carboxylase (PC) activity, leading to increased aspartate levels. This metabolic mechanism supports the argininosuccinate shunt, which fuels ureagenesis from arginine and conversely diminishes arginine utilization for production of nitric oxide (NO), a chief mediator of inflammatory cytotoxicity. Activation of the PC-urea cycle axis is sufficient to suppress NO synthesis and shield cells from death in the context of inflammation and other stress paradigms. Overall, these studies uncover a previously unappreciated link between glucose metabolism and arginine-utilizing pathways via PC-directed ureagenesis as a protective mechanism.
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http://dx.doi.org/10.1038/s42255-020-0199-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7568475PMC
May 2020

Repression of LKB1 by Sensitizes -Dependent Lymphoma to Biguanide Treatment.

Cell Rep Med 2020 May 19;1(2):100014. Epub 2020 May 19.

Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada.

Cancer cells display metabolic plasticity to survive stresses in the tumor microenvironment. Cellular adaptation to energetic stress is coordinated in part by signaling through the liver kinase B1 (LKB1)-AMP-activated protein kinase (AMPK) pathway. Here, we demonstrate that miRNA-mediated silencing of LKB1 confers sensitivity of lymphoma cells to mitochondrial inhibition by biguanides. Using both classic (phenformin) and newly developed (IM156) biguanides, we demonstrate that elevated expression in lymphoma cells promotes increased apoptosis to biguanide treatment and . This effect is driven by the -dependent silencing of LKB1, which reduces AMPK activation in response to complex I inhibition. Mechanistically, biguanide treatment induces metabolic stress in lymphoma cells by inhibiting TCA cycle metabolism and mitochondrial respiration, exposing metabolic vulnerability. Finally, we demonstrate a direct correlation between expression and biguanide sensitivity in human cancer cells. Our results identify expression as a potential biomarker for biguanide sensitivity in malignancies.
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http://dx.doi.org/10.1016/j.xcrm.2020.100014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7249503PMC
May 2020

Methotrexate elicits pro-respiratory and anti-growth effects by promoting AMPK signaling.

Sci Rep 2020 05 12;10(1):7838. Epub 2020 May 12.

Department of Biochemistry, McGill University, Montréal, QC, H3G 1Y6, Canada.

One-carbon metabolism fuels the high demand of cancer cells for nucleotides and other building blocks needed for increased proliferation. Although inhibitors of this pathway are widely used to treat many cancers, their global impact on anabolic and catabolic processes remains unclear. Using a combination of real-time bioenergetics assays and metabolomics approaches, we investigated the global effects of methotrexate on cellular metabolism. We show that methotrexate treatment increases the intracellular concentration of the metabolite AICAR, resulting in AMPK activation. Methotrexate-induced AMPK activation leads to decreased one-carbon metabolism gene expression and cellular proliferation as well as increased global bioenergetic capacity. The anti-proliferative and pro-respiratory effects of methotrexate are AMPK-dependent, as cells with reduced AMPK activity are less affected by methotrexate treatment. Conversely, the combination of methotrexate with the AMPK activator, phenformin, potentiates its anti-proliferative activity in cancer cells. These data highlight a reciprocal effect of methotrexate on anabolic and catabolic processes and implicate AMPK activation as a metabolic determinant of methotrexate response.
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http://dx.doi.org/10.1038/s41598-020-64460-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7217946PMC
May 2020

MicroRNA-9 Fine-Tunes Dendritic Cell Function by Suppressing Negative Regulators in a Cell-Type-Specific Manner.

Cell Rep 2020 05;31(5):107585

Department of Microbiology and Immunology, McGill University, Montreal, QC H3G 1Y6, Canada; Goodman Cancer Research Center, Department of Physiology, McGill University, Montreal, QC H3G 1Y6, Canada; Metabolic and Nutritional Programming Group, Van Andel Institute, 333 Bostwick Avenue NE, Grand Rapids, MI 49503, USA. Electronic address:

Dendritic cells, cells of the innate immune system, are found in a steady state poised to respond to activating stimuli. Once stimulated, they rapidly undergo dynamic changes in gene expression to adopt an activated phenotype capable of stimulating immune responses. We find that the microRNA miR-9 is upregulated in both bone marrow-derived DCs and conventional DC1s but not in conventional DC2s following stimulation. miR-9 expression in BMDCs and conventional DC1s promotes enhanced DC activation and function, including the ability to stimulate T cell activation and control tumor growth. We find that miR-9 regulated the expression of several negative regulators of transcription, including the transcriptional repressor Polycomb group factor 6 (Pcgf6). These findings demonstrate that miR-9 facilitates the transition of DCs from steady state to mature state by regulating the expression of several negative regulators of DC function in a cell-type-specific manner.
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http://dx.doi.org/10.1016/j.celrep.2020.107585DOI Listing
May 2020

Methionine Metabolism Shapes T Helper Cell Responses through Regulation of Epigenetic Reprogramming.

Cell Metab 2020 02;31(2):250-266.e9

Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada; Department of Physiology, McGill University, Montreal, QC H3G 1Y6, Canada; Metabolic and Nutritional Programming, Center for Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, MI 49503, USA. Electronic address:

Epigenetic modifications on DNA and histones regulate gene expression by modulating chromatin accessibility to transcription machinery. Here we identify methionine as a key nutrient affecting epigenetic reprogramming in CD4 T helper (Th) cells. Using metabolomics, we showed that methionine is rapidly taken up by activated T cells and serves as the major substrate for biosynthesis of the universal methyl donor S-adenosyl-L-methionine (SAM). Methionine was required to maintain intracellular SAM pools in T cells. Methionine restriction reduced histone H3K4 methylation (H3K4me3) at the promoter regions of key genes involved in Th17 cell proliferation and cytokine production. Applied to the mouse model of multiple sclerosis (experimental autoimmune encephalomyelitis), dietary methionine restriction reduced the expansion of pathogenic Th17 cells in vivo, leading to reduced T cell-mediated neuroinflammation and disease onset. Our data identify methionine as a key nutritional factor shaping Th cell proliferation and function in part through regulation of histone methylation.
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http://dx.doi.org/10.1016/j.cmet.2020.01.006DOI Listing
February 2020

Metabolic Profiling Using Stable Isotope Tracing Reveals Distinct Patterns of Glucose Utilization by Physiologically Activated CD8 T Cells.

Immunity 2019 11 10;51(5):856-870.e5. Epub 2019 Oct 10.

Metabolic and Nutritional Programming, Center for Cancer and Cell Biology, Van Andel Institute, Grand Rapids, MI 49503, USA; Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada; Department of Physiology, McGill University, Montreal, QC H3G 1Y6, Canada. Electronic address:

Naive CD8 T cells differentiating into effector T cells increase glucose uptake and shift from quiescent to anabolic metabolism. Although much is known about the metabolism of cultured T cells, how T cells use nutrients during immune responses in vivo is less well defined. Here, we combined bioenergetic profiling and C-glucose infusion techniques to investigate the metabolism of CD8 T cells responding to Listeria infection. In contrast to in vitro-activated T cells, which display hallmarks of Warburg metabolism, physiologically activated CD8 T cells displayed greater rates of oxidative metabolism, higher bioenergetic capacity, differential use of pyruvate, and prominent flow of C-glucose carbon to anabolic pathways, including nucleotide and serine biosynthesis. Glucose-dependent serine biosynthesis mediated by the enzyme Phgdh was essential for CD8 T cell expansion in vivo. Our data highlight fundamental differences in glucose use by pathogen-specific T cells in vivo, illustrating the impact of environment on T cell metabolic phenotypes.
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http://dx.doi.org/10.1016/j.immuni.2019.09.003DOI Listing
November 2019

SDHA gain-of-function engages inflammatory mitochondrial retrograde signaling via KEAP1-Nrf2.

Nat Immunol 2019 10 16;20(10):1311-1321. Epub 2019 Sep 16.

Center for Cancer and Cell Biology, Van Andel Institute, Grand Rapids, MI, USA.

Whether screening the metabolic activity of immune cells facilitates discovery of molecular pathology remains unknown. Here we prospectively screened the extracellular acidification rate as a measure of glycolysis and the oxygen consumption rate as a measure of mitochondrial respiration in B cells from patients with primary antibody deficiency. The highest oxygen consumption rate values were detected in three study participants with persistent polyclonal B cell lymphocytosis (PPBL). Exome sequencing identified germline mutations in SDHA, which encodes succinate dehydrogenase subunit A, in all three patients with PPBL. SDHA gain-of-function led to an accumulation of fumarate in PPBL B cells, which engaged the KEAP1-Nrf2 system to drive the transcription of genes encoding inflammatory cytokines. In a single patient trial, blocking the activity of the cytokine interleukin-6 in vivo prevented systemic inflammation and ameliorated clinical disease. Overall, our study has identified pathological mitochondrial retrograde signaling as a disease modifier in primary antibody deficiency.
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http://dx.doi.org/10.1038/s41590-019-0482-2DOI Listing
October 2019

Oncogenic Biogenesis of pri-miR-17∼92 Reveals Hierarchy and Competition among Polycistronic MicroRNAs.

Mol Cell 2019 07 26;75(2):340-356.e10. Epub 2019 Jun 26.

Department of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada; Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue W, Montreal, QC H3A 1A3, Canada. Electronic address:

The microRNAs encoded by the miR-17∼92 polycistron are commonly overexpressed in cancer and orchestrate a wide range of oncogenic functions. Here, we identify a mechanism for miR-17∼92 oncogenic function through the disruption of endogenous microRNA (miRNA) processing. We show that, upon oncogenic overexpression of the miR-17∼92 primary transcript (pri-miR-17∼92), the microprocessor complex remains associated with partially processed intermediates that aberrantly accumulate. These intermediates reflect a series of hierarchical and conserved steps in the early processing of the pri-miR-17∼92 transcript. Encumbrance of the microprocessor by miR-17∼92 intermediates leads to the broad but selective downregulation of co-expressed polycistronic miRNAs, including miRNAs derived from tumor-suppressive miR-34b/c and from the Dlk1-Dio3 polycistrons. We propose that the identified steps of polycistronic miR-17∼92 biogenesis contribute to the oncogenic re-wiring of gene regulation networks. Our results reveal previously unappreciated functional paradigms for polycistronic miRNAs in cancer.
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http://dx.doi.org/10.1016/j.molcel.2019.05.033DOI Listing
July 2019

Immature Low-Density Neutrophils Exhibit Metabolic Flexibility that Facilitates Breast Cancer Liver Metastasis.

Cell Rep 2019 06;27(13):3902-3915.e6

Goodman Cancer Research Centre, McGill University, Montreal, Québec, QC H3A 1A3, Canada; Department of Medicine, McGill University, Montreal, Québec, QC H3G 1Y6, Canada. Electronic address:

Neutrophils are phenotypically heterogeneous and exert either anti- or pro-metastatic functions. We show that cancer-cell-derived G-CSF is necessary, but not sufficient, to mobilize immature low-density neutrophils (iLDNs) that promote liver metastasis. In contrast, mature high-density neutrophils inhibit the formation of liver metastases. Transcriptomic and metabolomic analyses of high- and low-density neutrophils reveal engagement of numerous metabolic pathways specifically in low-density neutrophils. iLDNs exhibit enhanced global bioenergetic capacity, through their ability to engage mitochondrial-dependent ATP production, and remain capable of executing pro-metastatic neutrophil functions, including NETosis, under nutrient-deprived conditions. We demonstrate that NETosis is an important neutrophil function that promotes breast cancer liver metastasis. iLDNs rely on the catabolism of glutamate and proline to support mitochondrial-dependent metabolism in the absence of glucose, which enables sustained NETosis. These data reveal that distinct pro-metastatic neutrophil populations exhibit a high degree of metabolic flexibility, which facilitates the formation of liver metastases.
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http://dx.doi.org/10.1016/j.celrep.2019.05.091DOI Listing
June 2019

Hypoxia-inducible factors in CD4 T cells promote metabolism, switch cytokine secretion, and T cell help in humoral immunity.

Proc Natl Acad Sci U S A 2019 04 15;116(18):8975-8984. Epub 2019 Apr 15.

Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232;

T cell help in humoral immunity includes interactions of B cells with activated extrafollicular CD4 and follicular T helper (Tfh) cells. Each can promote antibody responses but Tfh cells play critical roles during germinal center (GC) reactions. After restimulation of their antigen receptor (TCR) by B cells, helper T cells act on B cells via CD40 ligand and secreted cytokines that guide Ig class switching. Hypoxia is a normal feature of GC, raising questions about molecular mechanisms governing the relationship between hypoxia response mechanisms and T cell help to antibody responses. Hypoxia-inducible factors (HIF) are prominent among mechanisms that mediate cellular responses to limited oxygen but also are induced by lymphocyte activation. We now show that loss of HIF-1α or of both HIF-1α and HIF-2α in CD4 T cells compromised essential functions in help during antibody responses. HIF-1α depletion from CD4 T cells reduced frequencies of antigen-specific GC B cells, Tfh cells, and overall antigen-specific Ab after immunization with sheep red blood cells. Compound deficiency of HIF-1α and HIF-2α led to humoral defects after hapten-carrier immunization. Further, HIF promoted CD40L expression while restraining the FoxP3-positive CD4 cells in the CXCR5 follicular regulatory population. Glycolysis increases T helper cytokine expression, and HIF promoted glycolysis in T helper cells via TCR or cytokine stimulation, as well as their production of cytokines that direct antibody class switching. Indeed, IFN-γ elaboration by HIF-deficient in vivo-generated Tfh cells was impaired. Collectively, the results indicate that HIF transcription factors are vital components of the mechanisms of help during humoral responses.
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http://dx.doi.org/10.1073/pnas.1811702116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6500120PMC
April 2019

Activation of Peroxisome Proliferator-Activated Receptors α and δ Synergizes with Inflammatory Signals to Enhance Adoptive Cell Therapy.

Cancer Res 2019 02 20;79(3):445-451. Epub 2018 Dec 20.

Princess Margaret Cancer Centre, Toronto, Ontario, Canada.

Memory CD8 T cells (T) are superior mediators of adoptive cell therapy (ACT) compared with effector CD8 T cells (T) due to increased persistence . Underpinning T survival is a shift in cellular metabolism away from aerobic glycolysis towards fatty acid oxidation (FAO). Here we investigated the impact of the peroxisome proliferator-activated receptor (PPAR) agonist GW501516 (GW), an agent known to boost FAO in other tissues, on CD8 T-cell metabolism, function, and efficacy in a murine ACT model. Via activation of both PPARα and PPARδ/β, GW treatment increased expression of carnitine palmitoyl transferase 1a, the rate-limiting enzyme of FAO, in activated CD8 T cells. Using a metabolomics approach, we demonstrated that GW increased the abundance of multiple different acylcarnitines, consistent with enhanced FAO. T cells activated in the presence of GW and inflammatory signals, either mature dendritic cells or IL12, also demonstrated enhanced production of IFNγ and expression of T-bet. Despite high expression of T-bet, a characteristic of short-lived effector cells, GW-treated cells demonstrated enhanced persistence and superior efficacy in a model of ACT. Collectively, these data identify combined PPARα and PPARδ/β agonists as attractive candidates for further studies and rapid translation into clinical trials of ACT. SIGNIFICANCE: Dual activation of peroxisome proliferator-activated receptors α and δ improves the efficacy of adoptive cell therapy by reprogramming T-cell metabolism and cytokine expression.
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http://dx.doi.org/10.1158/0008-5472.CAN-17-3053DOI Listing
February 2019

Translational and HIF-1α-Dependent Metabolic Reprogramming Underpin Metabolic Plasticity and Responses to Kinase Inhibitors and Biguanides.

Cell Metab 2018 12 20;28(6):817-832.e8. Epub 2018 Sep 20.

Lady Davis Institute, SMBD JGH, McGill University, Montreal, QC H3A 1A3, Canada; Gerald Bronfman Department of Oncology, McGill University, Montreal, QC H3A 1A3, Canada; Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada; Department of Experimental Medicine, McGill University, Montreal, QC H3A 1A3, Canada. Electronic address:

There is increasing interest in therapeutically exploiting metabolic differences between normal and cancer cells. We show that kinase inhibitors (KIs) and biguanides synergistically and selectively target a variety of cancer cells. Synthesis of non-essential amino acids (NEAAs) aspartate, asparagine, and serine, as well as glutamine metabolism, are major determinants of the efficacy of KI/biguanide combinations. The mTORC1/4E-BP axis regulates aspartate, asparagine, and serine synthesis by modulating mRNA translation, while ablation of 4E-BP1/2 substantially decreases sensitivity of breast cancer and melanoma cells to KI/biguanide combinations. Efficacy of the KI/biguanide combinations is also determined by HIF-1α-dependent perturbations in glutamine metabolism, which were observed in VHL-deficient renal cancer cells. This suggests that cancer cells display metabolic plasticity by engaging non-redundant adaptive mechanisms, which allows them to survive therapeutic insults that target cancer metabolism.
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http://dx.doi.org/10.1016/j.cmet.2018.09.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7252493PMC
December 2018

Etomoxir Actions on Regulatory and Memory T Cells Are Independent of Cpt1a-Mediated Fatty Acid Oxidation.

Cell Metab 2018 09 28;28(3):504-515.e7. Epub 2018 Jun 28.

Institute of Infection Immunology, TWINCORE, Centre for Experimental and Clinical Infection Research, A Joint Venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Niedersachsen 30625, Germany. Electronic address:

T cell subsets including effector (T), regulatory (T), and memory (T) cells are characterized by distinct metabolic profiles that influence their differentiation and function. Previous research suggests that engagement of long-chain fatty acid oxidation (LC-FAO) supports Foxp3 T cell and T cell survival. However, evidence for this is mostly based on inhibition of Cpt1a, the rate-limiting enzyme for LC-FAO, with the drug etomoxir. Using genetic models to target Cpt1a specifically in T cells, we dissected the role of LC-FAO in primary, memory, and regulatory T cell responses. Here we show that the ACC2/Cpt1a axis is largely dispensable for T, T, or T cell formation, and that the effects of etomoxir on T cell differentiation and function are independent of Cpt1a expression. Together our data argue that metabolic pathways other than LC-FAO fuel T or T differentiation and suggest alternative mechanisms for the effects of etomoxir that involve mitochondrial respiration.
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http://dx.doi.org/10.1016/j.cmet.2018.06.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6747686PMC
September 2018

Glycolytic metabolism is essential for CCR7 oligomerization and dendritic cell migration.

Nat Commun 2018 06 25;9(1):2463. Epub 2018 Jun 25.

Goodman Cancer Research Centre, Department of Physiology, McGill University, Montreal, QC, H3G 1Y6, Canada.

Dendritic cells (DCs) are first responders of the innate immune system that integrate signals from external stimuli to direct context-specific immune responses. Current models suggest that an active switch from mitochondrial metabolism to glycolysis accompanies DC activation to support the anabolic requirements of DC function. We show that early glycolytic activation is a common program for both strong and weak stimuli, but that weakly activated DCs lack long-term HIF-1α-dependent glycolytic reprogramming and retain mitochondrial oxidative metabolism. Early induction of glycolysis is associated with activation of AKT, TBK, and mTOR, and sustained activation of these pathways is associated with long-term glycolytic reprogramming. We show that inhibition of glycolysis impaired maintenance of elongated cell shape, DC motility, CCR7 oligomerization, and DC migration to draining lymph nodes. Together, our results indicate that early induction of glycolysis occurs independent of pro-inflammatory phenotype, and that glycolysis supports DC migratory ability regardless of mitochondrial bioenergetics.
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http://dx.doi.org/10.1038/s41467-018-04804-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6018630PMC
June 2018

The AMPK agonist 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), but not metformin, prevents inflammation-associated cachectic muscle wasting.

EMBO Mol Med 2018 07;10(7)

Department of Biochemistry, McGill University, Montreal, QC, Canada

Activation of AMPK has been associated with pro-atrophic signaling in muscle. However, AMPK also has anti-inflammatory effects, suggesting that in cachexia, a syndrome of inflammatory-driven muscle wasting, AMPK activation could be beneficial. Here we show that the AMPK agonist AICAR suppresses IFNγ/TNFα-induced atrophy, while the mitochondrial inhibitor metformin does not. IFNγ/TNFα impair mitochondrial oxidative respiration in myotubes and promote a metabolic shift to aerobic glycolysis, similarly to metformin. In contrast, AICAR partially restored metabolic function. The effects of AICAR were prevented by the AMPK inhibitor Compound C and were reproduced with A-769662, a specific AMPK activator. AICAR and A-769662 co-treatment was found to be synergistic, suggesting that the anti-cachectic effects of these drugs are mediated through AMPK activation. AICAR spared muscle mass in mouse models of cancer and LPS induced atrophy. Together, our findings suggest a dual function for AMPK during inflammation-driven atrophy, wherein it can play a protective role when activated exogenously early in disease progression, but may contribute to anabolic suppression and atrophy when activated later through mitochondrial dysfunction and subsequent metabolic stress.
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http://dx.doi.org/10.15252/emmm.201708307DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6034131PMC
July 2018

Mitochondrial cyclophilin D regulates T cell metabolic responses and disease tolerance to tuberculosis.

Sci Immunol 2018 05;3(23)

Department of Medicine, Department of Microbiology and Immunology, Department of Pathology, McGill University Health Centre, McGill International TB Centre, Meakins-Christie Laboratories, McGill University, 1001 Decarie Boulevard, Montreal, Quebec H4A 3J1, Canada.

() is one of the most ancient human pathogens, yet the exact mechanism(s) of host defense against remains unclear. Although one-third of the world's population is chronically infected with , only 5 to 10% develop active disease. This indicates that, in addition to resistance mechanisms that control bacterial burden, the host has also evolved strategies to tolerate the presence of to limit disease severity. We identify mitochondrial cyclophilin D (CypD) as a critical checkpoint of T cell metabolism that controls the expansion of activated T cells. Although loss of CypD function in T cells led to enhanced antigen-specific T cell responses, this increased T cell response had no impact on bacterial burden. Rather, mice containing CypD-deficient T cells exhibited substantially compromised disease tolerance and succumbed to infection. This study establishes a mechanistic link between T cell-mediated immunity and disease tolerance during infection.
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http://dx.doi.org/10.1126/sciimmunol.aar4135DOI Listing
May 2018

Fatty acid metabolism in CD8 T cell memory: Challenging current concepts.

Immunol Rev 2018 05;283(1):213-231

Institute of Infection Immunology, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany.

CD8 T cells are key members of the adaptive immune response against infections and cancer. As we discuss in this review, these cells can present diverse metabolic requirements, which have been intensely studied during the past few years. Our current understanding suggests that aerobic glycolysis is a hallmark of activated CD8 T cells, while naive and memory (T ) cells often rely on oxidative phosphorylation, and thus mitochondrial metabolism is a crucial determinant of CD8 T cell development. Moreover, it has been proposed that CD8 T cells have a specific requirement for the oxidation of long-chain fatty acids (LC-FAO), a process modulated in lymphocytes by the enzyme CPT1A. However, this notion relies heavily on the metabolic analysis of in vitro cultures and on chemical inhibition of CPT1A. Therefore, we introduce more recent studies using genetic models to demonstrate that CPT1A-mediated LC-FAO is dispensable for the development of CD8 T cell memory and protective immunity, and question the use of chemical inhibitors to target this enzyme. We discuss insights obtained from those and other studies analyzing the metabolic characteristics of CD8 T cells, and emphasize how T cells exhibit flexibility in their choice of metabolic fuel.
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http://dx.doi.org/10.1111/imr.12655DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6691976PMC
May 2018

Translational control in the tumor microenvironment promotes lung metastasis: Phosphorylation of eIF4E in neutrophils.

Proc Natl Acad Sci U S A 2018 03 20;115(10):E2202-E2209. Epub 2018 Feb 20.

Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada;

The translation of mRNAs into proteins serves as a critical regulatory event in gene expression. In the context of cancer, deregulated translation is a hallmark of transformation, promoting the proliferation, survival, and metastatic capabilities of cancer cells. The best-studied factor involved in the translational control of cancer is the eukaryotic translation initiation factor 4E (eIF4E). We and others have shown that eIF4E availability and phosphorylation promote metastasis in mouse models of breast cancer by selectively augmenting the translation of mRNAs involved in invasion and metastasis. However, the impact of translational control in cell types within the tumor microenvironment (TME) is unknown. Here, we demonstrate that regulatory events affecting translation in cells of the TME impact cancer progression. Mice bearing a mutation in the phosphorylation site of eIF4E (S209A) in cells comprising the TME are resistant to the formation of lung metastases in a syngeneic mammary tumor model. This is associated with reduced survival of prometastatic neutrophils due to decreased expression of the antiapoptotic proteins BCL2 and MCL1. Furthermore, we demonstrate that pharmacological inhibition of eIF4E phosphorylation prevents metastatic progression in vivo, supporting the development of phosphorylation inhibitors for clinical use.
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http://dx.doi.org/10.1073/pnas.1717439115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5877985PMC
March 2018

AMPK Maintains Cellular Metabolic Homeostasis through Regulation of Mitochondrial Reactive Oxygen Species.

Cell Rep 2017 Oct;21(1):1-9

Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada; Department of Physiology, McGill University, Montreal, QC H3G 1Y6, Canada. Electronic address:

Reactive oxygen species (ROS) are continuously produced as a by-product of mitochondrial metabolism and eliminated via antioxidant systems. Regulation of mitochondrially produced ROS is required for proper cellular function, adaptation to metabolic stress, and bypassing cellular senescence. Here, we report non-canonical regulation of the cellular energy sensor AMP-activated protein kinase (AMPK) by mitochondrial ROS (mROS) that functions to maintain cellular metabolic homeostasis. We demonstrate that mitochondrial ROS are a physiological activator of AMPK and that AMPK activation triggers a PGC-1α-dependent antioxidant response that limits mitochondrial ROS production. Cells lacking AMPK activity display increased mitochondrial ROS levels and undergo premature senescence. Finally, we show that AMPK-PGC-1α-dependent control of mitochondrial ROS regulates HIF-1α stabilization and that mitochondrial ROS promote the Warburg effect in cells lacking AMPK signaling. These data highlight a key function for AMPK in sensing and resolving mitochondrial ROS for stress resistance and maintaining cellular metabolic balance.
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http://dx.doi.org/10.1016/j.celrep.2017.09.026DOI Listing
October 2017

MenTORing Immunity: mTOR Signaling in the Development and Function of Tissue-Resident Immune Cells.

Immunity 2017 05;46(5):730-742

Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany. Electronic address:

Tissue-resident immune cells must balance survival in peripheral tissues with the capacity to respond rapidly upon infection or tissue damage, and in turn couple these responses with intrinsic metabolic control and conditions in the tissue microenvironment. The serine/threonine kinase mammalian/mechanistic target of rapamycin (mTOR) is a central integrator of extracellular and intracellular growth signals and cellular metabolism and plays important roles in both innate and adaptive immune responses. This review discusses the function of mTOR signaling in the differentiation and function of tissue-resident immune cells, with focus on the role of mTOR as a metabolic sensor and its impact on metabolic regulation in innate and adaptive immune cells. We also discuss the impact of metabolic constraints in tissues on immune homeostasis and disease, and how manipulating mTOR activity with drugs such as rapamycin can modulate immunity in these contexts.
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http://dx.doi.org/10.1016/j.immuni.2017.04.028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5695239PMC
May 2017

The role of AMPK in T cell metabolism and function.

Curr Opin Immunol 2017 Jun 28;46:45-52. Epub 2017 Apr 28.

Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada; Department of Physiology, McGill University, Montreal, QC H3G 1Y6, Canada. Electronic address:

The AMP-activated protein kinase (AMPK) is a key metabolic regulator that both senses changes in cellular energy levels and activates pathways to maintain cellular energy balance. AMPK achieves this by stimulating catabolic pathways that generate ATP and inhibiting biological pathways that consume ATP consumption. Recent work has established that AMPK is activated in T cells by both immunological and environmental stimuli, and plays an important role in T cell metabolism, in part by controlling T cell 'metabolic plasticity'. Recent data have revealed distinct functions for AMPK in T cells, including effects on memory T cell development, cytokine production, and potentially anti-tumor responses. In this review, we discuss recent advances in our understanding of AMPK function in T cells, and discuss future research areas for this energy-sensing pathway in lymphocytes.
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http://dx.doi.org/10.1016/j.coi.2017.04.004DOI Listing
June 2017

Serine Is an Essential Metabolite for Effector T Cell Expansion.

Cell Metab 2017 02 19;25(2):345-357. Epub 2017 Jan 19.

Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada; Department of Physiology, McGill University, Montreal, QC H3G 1Y6, Canada. Electronic address:

During immune challenge, T lymphocytes engage pathways of anabolic metabolism to support clonal expansion and the development of effector functions. Here we report a critical role for the non-essential amino acid serine in effector T cell responses. Upon activation, T cells upregulate enzymes of the serine, glycine, one-carbon (SGOC) metabolic network, and rapidly increase processing of serine into one-carbon metabolism. We show that extracellular serine is required for optimal T cell expansion even in glucose concentrations sufficient to support T cell activation, bioenergetics, and effector function. Restricting dietary serine impairs pathogen-driven expansion of T cells in vivo, without affecting overall immune cell homeostasis. Mechanistically, serine supplies glycine and one-carbon units for de novo nucleotide biosynthesis in proliferating T cells, and one-carbon units from formate can rescue T cells from serine deprivation. Our data implicate serine as a key immunometabolite that directly modulates adaptive immunity by controlling T cell proliferative capacity.
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http://dx.doi.org/10.1016/j.cmet.2016.12.011DOI Listing
February 2017

The oncometabolite 2-hydroxyglutarate activates the mTOR signalling pathway.

Nat Commun 2016 09 14;7:12700. Epub 2016 Sep 14.

Département de Biochimie et Médecine Moléculaire, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, Quebec, Canada H3C 3J7.

The identification of cancer-associated mutations in the tricarboxylic acid (TCA) cycle enzymes isocitrate dehydrogenases 1 and 2 (IDH1/2) highlights the prevailing notion that aberrant metabolic function can contribute to carcinogenesis. IDH1/2 normally catalyse the oxidative decarboxylation of isocitrate into α-ketoglutarate (αKG). In gliomas and acute myeloid leukaemias, IDH1/2 mutations confer gain-of-function leading to production of the oncometabolite R-2-hydroxyglutarate (2HG) from αKG. Here we show that generation of 2HG by mutated IDH1/2 leads to the activation of mTOR by inhibiting KDM4A, an αKG-dependent enzyme of the Jumonji family of lysine demethylases. Furthermore, KDM4A associates with the DEP domain-containing mTOR-interacting protein (DEPTOR), a negative regulator of mTORC1/2. Depletion of KDM4A decreases DEPTOR protein stability. Our results provide an additional molecular mechanism for the oncogenic activity of mutant IDH1/2 by revealing an unprecedented link between TCA cycle defects and positive modulation of mTOR function downstream of the canonical PI3K/AKT/TSC1-2 pathway.
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http://dx.doi.org/10.1038/ncomms12700DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5027283PMC
September 2016
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