Project description:Natural Killer (NK) cells, integral to viral immunity and tumor clearance, are impacted by metabolism. A prior study revealed that cytokine stimulation boosts the citrate-malate shuttle and cytosolic acetyl-CoA through ATP citrate lyase (ACLY) in NK cells. Acetyl-CoA is vital for fatty acid synthesis and protein acetylation, including histones. To explore the role of ACLY in NK cell function, we generated an inducible NK-specific Acly knockout mouse model. ACLY loss in NKp46+ NK cells did not alter maturation or IFN-γ production in naïve NK cells. However, ACLY-deficient NK cells exhibited notable proliferation defects in IL-15-priming conditions, associated with impaired glycolysis. The stimulation and priming of NK cells through IL-15 is an important mechanism for enhancing effector and anti-tumor functions. Additionally, IL-15-primed ACLY-deficient NK cells showed reduced effector function in response to DAP12-associated activating receptors (NKG2D, Ly49H). This is because ACLY-deficient NK cells produce lower level of DAP12 during IL-15 priming, which was regulated in epigenetic level. These ACLY-driven deficiency was mostly rescued by acetate-generated acetyl-CoA, except glycolysis. Overall, these findings underscore ACLY's importance in NK cell proliferation and DAP12-driven effector functions.
Project description:Natural Killer (NK) cells, integral to viral immunity and tumor clearance, are impacted by metabolism. A prior study revealed that cytokine stimulation boosts the citrate-malate shuttle and cytosolic acetyl-CoA through ATP citrate lyase (ACLY) in NK cells. Acetyl-CoA is vital for fatty acid synthesis and protein acetylation, including histones. To explore the role of ACLY in NK cell function, we generated an inducible NK-specific Acly knockout mouse model. ACLY loss in NKp46+ NK cells did not alter maturation or IFN-γ production in naïve NK cells. However, ACLY-deficient NK cells exhibited notable proliferation defects in IL-15-priming conditions, associated with impaired glycolysis. The stimulation and priming of NK cells through IL-15 is an important mechanism for enhancing effector and anti-tumor functions. Additionally, IL-15-primed ACLY-deficient NK cells showed reduced effector function in response to DAP12-associated activating receptors (NKG2D, Ly49H). This is because ACLY-deficient NK cells produce lower level of DAP12 during IL-15 priming, which was regulated in epigenetic level. These ACLY-driven deficiency was mostly rescued by acetate-generated acetyl-CoA, except glycolysis. Overall, these findings underscore ACLY's importance in NK cell proliferation and DAP12-driven effector functions.
Project description:Coordination of cellular metabolism is essential for optimal T cell responses. Here, we identify cytosolic acetyl-CoA production as an essential metabolic node for CD8 T cell function in vivo. We show that CD8 T cell responses to infection depend on acetyl-CoA derived from citrate via the enzyme Acly (ATP citrate lyase). However, ablation of Acly triggers an alternative, acetate-dependent pathway for acetyl-CoA production mediated by Acss2 (acyl-CoA synthetase short chain family member 2). Mechanistically, acetate fuels both the TCA cycle and cytosolic acetyl-CoA production, impacting T cell effector responses, acetate-dependent histone acetylation, and chromatin accessibility at effector gene loci. When Acly is functional, Acss2 is not required, suggesting acetate is not an obligate metabolic substrate for CD8 T cell function. However, deletion of Acly renders CD8 T cells dependent on acetate (via Acss2) to maintain acetyl-CoA production and effector function. Thus, together Acly and Acss2 coordinate cytosolic acetyl-CoA production in CD8 T cells to maintain chromatin accessibility and T cell effector function.
Project description:Coordination of cellular metabolism is essential for optimal T cell responses. Here, we identify cytosolic acetyl-CoA production as an essential metabolic node for CD8 T cell function in vivo. We show that acetyl-CoA derived from mitochondrial citrate via the enzyme ATP citrate lyase (Acly) is required for CD8 T cell responses to infection. However, ablation of Acly triggers an alternative, acetate-dependent pathway for acetyl-CoA production in T cells mediated by acyl-CoA synthetase short chain family member 2 (Acss2). Mechanistically, acetate fuels both the TCA cycle and cytosolic acetyl-CoA production, impacting T cell effector responses, acetate-dependent histone acetylation, and effector gene expression by altering chromatin accessibility. When Acly is functional, Acss2 is not required, suggesting acetate is not an obligate metabolic substrate for CD8 T cell function. However, deletion of Acly renders CD8 T cells dependent on acetate (via Acss2) to maintain acetyl-CoA production and effector function. Thus, together Acly and Acss2 coordinate cytosolic acetyl-CoA production in CD8 T cells to maintain chromatin accessibility and T cell effector function.
Project description:Coordination of cellular metabolism is essential for optimal T cell responses. Here, we identify cytosolic acetyl-CoA production as an essential metabolic node for CD8 T cell function in vivo. We show that CD8 T cell responses to infection depend on acetyl-CoA derived from citrate via the enzyme ATP citrate lyase (ACLY). However, ablation of ACLY triggers an alternative, acetate-dependent pathway for acetyl-CoA production mediated by acyl-CoA synthetase short chain family member 2 (ACSS2). Mechanistically, acetate fuels both the TCA cycle and cytosolic acetyl-CoA production, impacting T cell effector responses, acetate-dependent histone acetylation, and chromatin accessibility at effector gene loci. When ACLY is functional, ACSS2 is not required, suggesting acetate is not an obligate metabolic substrate for CD8 T cell function. However, loss of ACLY renders CD8 T cells dependent on acetate (via ACSS2) to maintain acetyl-CoA production and effector function. Together, ACLY and ACSS2 coordinate cytosolic acetyl-CoA production in CD8 T cells to maintain chromatin accessibility and T cell effector function.
Project description:In order to provide more evidence to prove that BCAAs catabolism mediates the expressions of FASN and ACLY by altering histone acetylation in melanoma, ChIP-seq of xenografted A2058 tumors implanted in mice receiving BCAA dietary interventions (normal or high BCAA diet) was employed to idenfity the enrichment of histone acetylation on the promoter of FASN and ACLY.
Project description:De novo lipogenesis is activated in most cancers. Several lipogenic enzymes are implicated in oncogenesis and represent potential cancer therapeutic targets. RNA interference-mediated depletion of ATP citrate lyase (ACLY), the enzyme that catalyzes the first step of de novo lipogenesis, leads to growth suppression in a subset of human cancer cells. Here we demonstrate the molecular basis and potential biomarkers for ACLY-targeting therapy. First, suppression of cancer cell growth by ACLY depletion involves down-regulation of fatty acid elongase ELOVL6 at the transcriptional level. Lipid profiling revealed that ACLY depletion alters fatty acid composition in triglyceride; increased palmitate and decreased longer fatty acids, in accordance with ELOVL6 down-regulation. Second, ACLY depletion increases reactive oxygen species (ROS), whereas addition of antioxidant reduces ROS and attenuates the growth suppression. Third, ACLY depletion or ROS stimulation induce phosphorylation of AMP-activated protein kinase (AMPK), a sensor of energy and lipid metabolism. Analysis of various cancer cell lines revealed that the levels of AMPK phosphorylation (p-AMPK) correlate with the basal ROS levels, and that cancer cells with low basal p-AMPK (i.e., low basal ROS) levels are highly susceptible to ACLY depletion-mediated growth suppression. Finally, in clinical colon cancer tissues, p-AMPK levels are significantly decreased in aggressive tumors and correlate with the levels of 8-hydroxydeoxyguanosine, a hallmark of ROS stimulation. Together, these data suggest that ACLY inhibition suppresses cancer growth via palmitate-mediated lipotoxicity, and p-AMPK could be a predictive biomarker for its therapeutic outcome. Two cell lines are treated with ACLY siRNA. The samples include controls of each cell line.