Menk et al. discovered that TCR signaling activates pyruvate dehydrogenase kinase 1 (PDHK1), which leads to an immediate metabolic switch to aerobic glycolysis by inhibiting intake of pyruvate into the mitochondria, resulting in lactate secretion via lactate dehydrogenase (LDH). Early cytokine (IFNγ, TNFα, IL-2) production is controlled by the PDHK1-mediated metabolic switch via release of LDH from its repressive translational role on RNA, but PDHK1 does not regulate other effector functions such as cytotoxicity or proliferation.

To fulfill bioenergetic demands of activation, T cells perform aerobic glycolysis, a process common to highly proliferative cells in which glucose is fermented into lactate rather than oxidized in mitochondria. However, the signaling events that initiate aerobic glycolysis in T cells remain unclear. We show T cell activation rapidly induces glycolysis independent of transcription, translation, CD28, and Akt and not involving increased glucose uptake or activity of glycolytic enzymes. Rather, TCR signaling promotes activation of pyruvate dehydrogenase kinase 1 (PDHK1), inhibiting mitochondrial import of pyruvate and facilitating breakdown into lactate. Inhibition of PDHK1 reveals this switch is required acutely for cytokine synthesis but dispensable for cytotoxicity. Functionally, cytokine synthesis is modulated via lactate dehydrogenase, which represses cytokine mRNA translation when aerobic glycolysis is disengaged. Our data provide mechanistic insight to metabolic contribution to effector T cell function and suggest that T cell function may be finely tuned through modulation of glycolytic activity.

Author Info: (1) Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15232, USA. (2) Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15232, USA; Department

Author Info: (1) Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15232, USA. (2) Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15232, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15213, USA. (3) Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15232, USA. (4) Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15232, USA; Tsinghua Medical University, Beijing, China. (5) St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (6) Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA. (7) Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21701, USA. (8) Cell Signaling Technology, Inc., Danvers, MA 01923, USA. (9) Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21701, USA. (10) Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA. (11) Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15232, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15213, USA. Electronic address: gdelgoffe@pitt.edu.

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