ABSTRACT: Short-term hypoxia synergizes with interleukin 15 priming in driving glycolytic gene transcription and supports human natural killer cell activities.
Project description:Natural killer (NK) cells induce apoptosis in infected and transformed cells and produce immunoregulatory cytokines. At this, NK cells operate in inflammatory and tumor environments low in oxygen (hypoxic) and with immunosuppressive properties. In vitro studies of NK cells are, however, commonly performed in ambient air (normoxia). We evaluated the immediate impact of short-term hypoxia on various intrinsic activities of resting and IL-15 primed NK cells and determined underlying transcriptional pathway regulations using a 2 × 2 factorial design. Hypoxia stimulated migration through extracellular matrix, supported secretion of specific chemokines, and shifted amounts of susceptible leukemia target cells toward late apoptosis. IL-15 was a powerful inducer of anabolic gene transcription. Associations of hypoxia with HIF-1 and glycolytic pathways were dependent on priming which represented the largest contrasts observed. Regulatory patterns and RT-PCR validated synergistic hypoxia-IL-15 interactions in upregulation of key glycolytic enzymes suggest an important function for anaerobic glycolysis in priming, underpinning the emerging role of glycolytic switching in driving NK cell function. Adaption to short-term hypoxia appeared however transitory. We conclude that control of oxygen in vitro can promote NK cell features desirable for adoptive transfer therapy.
Project description:This is a mathematical model comprised of non-linear ordinary differential equations describing the dynamic relationship between hypoxia-inducible factor-1 alpha (HIF-1a) mRNA, HIF-1a protein, and interleukin-15-mediated upstream signalling events in natural killer cells from human blood. Regulatory expressions are also included for mammalian target of rapamycin (mTOR), nuclear factor-kappa beta, and signal transducer and activator of transcription 3 (STAT3).
Project description:Environmental hypoxia typically induces phenotypic remodelling in animals, including bolstered oxygen transport and storage, and glycolytic enzyme activities, typically coordinated by the transcription factor hypoxia-inducible factor (HIF). The calanoid copepod Daphnia responds to hypoxia by a HIF-dependent increase in expression of extracellular hemoglobin (Hb), however little is known about the glycolytic response. We compared the Daphnia from 4 lakes in terms of transcriptome using RNASeq analysis of red versus pale animals. Cluster analysis showed that the impact of lake was much greater than the impact of colour. However, in each lake there were a series of colour dependent differences, including many of the known targets of HIF in mammals.
Project description:Upon antigen stimulation, the bioenergetic demands of T cells increase dramatically over the resting state. Although a role for the metabolic switch to glycolysis has been suggested to support increased anabolic activities and facilitate T cell growth and proliferation, whether cellular metabolism controls T cell lineage choices remains poorly understood. Here we report that the glycolytic pathway is actively regulated during the differentiation of inflammatory TH17 and Foxp3-expressing regulatory T cells (Treg), and controls cell fate determination. TH17 but not Treg-inducing conditions resulted in strong upregulation of the glycolytic activity and induction of glycolytic enzymes. Blocking glycolysis inhibited TH17 development while promoting Treg cell generation. Moreover, the transcription factor hypoxia-inducible factor 1a (HIF1a) was selectively expressed in TH17 cells and its induction required signaling through mTOR, a central regulator of cellular metabolism. HIF1a-dependent transcriptional program was important for mediating glycolytic activity, thereby contributing to the lineage choices between TH17 and Treg cells. Lack of HIF1a resulted in diminished TH17 development but enhanced Treg differentiation, and protected mice from autoimmune CNS inflammation. Our studies demonstrate that HIF1a-dependent glycolytic pathway orchestrates a metabolic checkpoint for the differentiation of TH17 and Treg cells. Naïve CD4 T cells from wild-type and HIF1a-deficient mice (in triplicates each group) were differentiated under TH17 conditions for 2.5 days, and RNA was analyzed by microarrays.
Project description:Antibodies targeting “immune checkpoints” have revolutionized cancer therapy by reactivating tumor-resident cytotoxic lymphocytes, primarily CD8 T cells. Interest in targeting analogous pathways in other cytotoxic lymphocytes is growing. Natural killer (NK) cells are key to cancer immunosurveillance by eradicating metastases and driving solid tumor inflammation. NK cell anti-tumor function is dependent on the cytokine interleukin (IL)-15. Ablation of the IL-15 signaling inhibitor CIS (Cish) enhances NK cell anti-tumor immunity by increasing NK cell metabolism and persistence within the tumor microenvironment (TME). The TME has also been shown to impair NK cell fitness via the production of immunosuppressive TGF-b, a suppression which occurs even in the presence of high IL-15 signaling. Here, we identified an unexpected interaction between CIS and the TGF-b signaling pathway in NK cells. Independently, Cish- and Tgfbr2- deficient NK cells are both hyper-responsive to IL-15 and hypo-responsive to TGF-b, with dramatically enhanced anti-tumor immunity. Remarkably, when both these immunosuppressive genes are simultaneously deleted in NK cells, mice are largely resistant to tumor development, suggesting that combining suppression of these two pathways might represent a novel therapeutic strategy to enhance innate anti-cancer immunity.
Project description:The metabolic adaptation of eukaryotic cells to hypoxia involves increasing dependence upon glycolytic ATP production, an event with consequences for both cell bioenergetics and cell fate. This response is regulated at the transcriptional level by HIF-1-dependent transcriptional upregulation of all ten glycolytic enzymes. However, this response alone does not account for the levels of ATP produced in hypoxia. Here, we investigated additional mechanisms of regulating glycolysis in hypoxia. We found that both intestinal epithelial cells treated with inhibitors of transcription and translation and human platelets (which lack nuclei) maintained the capacity for hypoxia-induced glycolysis, suggesting the involvement of a non-transcriptional component to the hypoxia-induced metabolic switch to a highly glycolytic phenotype. Mass spectrometric analysis of the interactome of immunoprecipitated rate-limiting glycolytic enzymes identified hypoxia-sensitive complexes comprising multiple glycolytic enzymes and glucose transporters in intestinal epithelial cells. Surprisingly, the formation of glycolytic complexes, though not dependent upon transcription, occurs via a HIF-1?-dependent mechanism, suggesting that HIF-1? may play a moonlighting role in the formation / maintenance of glycolytic complexes. Furthermore, we provide evidence for the presence of HIF-1? in cytosolic fractions of hypoxic cells which physically associated with the glucose transporter GLUT1 and the glycolytic enzyme PFKP in a hypoxia-sensitive manner. In conclusion, we hypothesize that HIF-1? plays a role in initiation and/or maintenance of glycolytic complexes in intestinal epithelial cells under hypoxic conditions in a manner which optimizes catalytic efficiency of the pathway by facilitating substrate channeling of glycolytic intermediates between sequential pathway enzymes. In hypoxia, cells undergo a metabolic switch to increased glycolysis. This has important implications for cell behavior, phenotype, and fate in both healthy and cancerous cells. Here we describe a mechanism by which HIF-1, in addition to increasing glycolytic enzyme expression, promotes glycolysis via the formation of a metabolic complex.
Project description:The metabolic adaptation of eukaryotic cells to hypoxia involves increasing dependence upon glycolytic ATP production, an event with consequences for both cell bioenergetics and cell fate. This response is regulated at the transcriptional level by HIF-1-dependent transcriptional upregulation of all ten glycolytic enzymes. However, this response alone does not account for the levels of ATP produced in hypoxia. Here, we investigated additional mechanisms of regulating glycolysis in hypoxia. We found that both intestinal epithelial cells treated with inhibitors of transcription and translation and human platelets (which lack nuclei) maintained the capacity for hypoxia-induced glycolysis, suggesting the involvement of a non-transcriptional component to the hypoxia-induced metabolic switch to a highly glycolytic phenotype. Mass spectrometric analysis of the interactome of immunoprecipitated rate-limiting glycolytic enzymes identified hypoxia-sensitive complexes comprising multiple glycolytic enzymes and glucose transporters in intestinal epithelial cells. Surprisingly, the formation of glycolytic complexes, though not dependent upon transcription, occurs via a HIF-1?-dependent mechanism, suggesting that HIF-1? may play a moonlighting role in the formation / maintenance of glycolytic complexes. Furthermore, we provide evidence for the presence of HIF-1? in cytosolic fractions of hypoxic cells which physically associated with the glucose transporter GLUT1 and the glycolytic enzyme PFKP in a hypoxia-sensitive manner. In conclusion, we hypothesize that HIF-1? plays a role in initiation and/or maintenance of glycolytic complexes in intestinal epithelial cells under hypoxic conditions in a manner which optimizes catalytic efficiency of the pathway by facilitating substrate channeling of glycolytic intermediates between sequential pathway enzymes. In hypoxia, cells undergo a metabolic switch to increased glycolysis. This has important implications for cell behavior, phenotype, and fate in both healthy and cancerous cells. Here we describe a mechanism by which HIF-1, in addition to increasing glycolytic enzyme expression, promotes glycolysis via the formation of a metabolic complex.
Project description:The metabolic adaptation of eukaryotic cells to hypoxia involves increasing dependence upon glycolytic ATP production, an event with consequences for both cell bioenergetics and cell fate. This response is regulated at the transcriptional level by HIF-1-dependent transcriptional upregulation of all ten glycolytic enzymes. However, this response alone does not account for the levels of ATP produced in hypoxia. Here, we investigated additional mechanisms of regulating glycolysis in hypoxia. We found that both intestinal epithelial cells treated with inhibitors of transcription and translation and human platelets (which lack nuclei) maintained the capacity for hypoxia-induced glycolysis, suggesting the involvement of a non-transcriptional component to the hypoxia-induced metabolic switch to a highly glycolytic phenotype. Mass spectrometric analysis of the interactome of immunoprecipitated rate-limiting glycolytic enzymes identified hypoxia-sensitive complexes comprising multiple glycolytic enzymes and glucose transporters in intestinal epithelial cells. Surprisingly, the formation of glycolytic complexes, though not dependent upon transcription, occurs via a HIF-1?-dependent mechanism, suggesting that HIF-1? may play a moonlighting role in the formation / maintenance of glycolytic complexes. Furthermore, we provide evidence for the presence of HIF-1? in cytosolic fractions of hypoxic cells which physically associated with the glucose transporter GLUT1 and the glycolytic enzyme PFKP in a hypoxia-sensitive manner. In conclusion, we hypothesize that HIF-1? plays a role in initiation and/or maintenance of glycolytic complexes in intestinal epithelial cells under hypoxic conditions in a manner which optimizes catalytic efficiency of the pathway by facilitating substrate channeling of glycolytic intermediates between sequential pathway enzymes. In hypoxia, cells undergo a metabolic switch to increased glycolysis. This has important implications for cell behavior, phenotype, and fate in both healthy and cancerous cells. Here we describe a mechanism by which HIF-1, in addition to increasing glycolytic enzyme expression, promotes glycolysis via the formation of a metabolic complex.