Stimulated CD4+ T lymphocytes can differentiate into effector T cell (Teff) or inducible regulatory T cell (Treg) subsets with specific immunological roles. We show that Teff and Treg require distinct metabolic programs to support these functions. Th1, Th2, and Th17 cells expressed high surface levels of the glucose transporter Glut1 and were highly glycolytic. Treg, in contrast, expressed low levels of Glut1 and had high lipid oxidation rates. Consistent with glycolysis and lipid oxidation promoting Teff and Treg, respectively, Teff were selectively increased in Glut1 transgenic mice and reliant on glucose metabolism, whereas Treg had activated AMP-activated protein kinase and were dependent on lipid oxidation. Importantly, AMP-activated protein kinase stimulation was sufficient to decrease Glut1 and increase Treg generation in an asthma model. These data demonstrate that CD4+ T cell subsets require distinct metabolic programs that can be manipulated in vivo to control Treg and Teff development in inflammatory diseases.
provided expertise to develop 18 F nutrient uptake assays. F.X. and M.N.T injected and handled mice for 18 F nutrient uptake assays, and performed and provided expertise for PET imaging and autoradiography. T.H. and W.D.M. performed and provided expertise for intrarenal Renca experiments. R.W.J. and V.T.M generated and provided expertise for PyMT GEMM tumors. R.E.B and C.S.W. generated and provided expertise for AOM/DSS CRC tumors. B.I.R. R.T.O. and M.H.W. generated the pTZeo-EL-thy1.1 transposon construct and engineered MC38 cells using this transposon system. B.I.R, M.Z.M, and A.S. performed in vivo 2NBDG studies. J.E.B. provided expertise in characterizing TAM. A.R.P provided expertise in flow sorting for mRNA transcript analysis. B.I.R. and M.Z.M performed extracellular flux and mRNA transcript experiments. F.M.M. and E.F.M performed and provided expertise in cell staining for light microscopy. E.F.M performed light microscopy and pathologic examination of MC38 tumors. A.A (VU) conducted transcriptomic analysis. B.I.R and M.Z.M. analyzed all data generated in this study. J.C.R. and W.K.R. obtained funding for this study.Data Availability Statement (DAS) All data will be made available upon reasonable request to JCR/WKR. Tumor mRNA transcript data that support the findings of this study have been deposited in Gene Expression Omnibus (GEO) under accession GSE165223. These data are also found in Supplementary Information Table 4. Code Availability Statement (CAS)The code used to support tumor mRNA transcript analysis has been previously published (see methods references) and will be made available upon request to JCR/WKR.
Hematopoietic cells normally require cell extrinsic signals to maintain metabolism and survival. In contrast, cancer cells can express constitutively active oncogenic kinases such as BCR-Abl that promote these processes independent of extrinsic growth factors. When cells receive insufficient growth signals or when oncogenic kinases are inhibited, glucose metabolism decreases and the self-digestive process of autophagy is elevated to degrade bulk cytoplasm and organelles. While autophagy has been proposed to provide a cell-intrinsic nutrient supply for mitochondrial oxidative metabolism and to maintain cellular homeostasis through degradation of damaged organelles or protein aggregates, its acute role in growth factor deprivation or inhibition of oncogenic kinases remains poorly understood. We therefore developed a growth factor-dependent hematopoietic cell culture model in which autophagy can be acutely disrupted through conditional Cre-mediated excision of the autophagy-essential gene Atg3. Treated cells rapidly lost their ability to perform autophagy and underwent cell cycle arrest and apoptosis. While Atg3 was essential for optimal upregulation of mitochondrial oxidative pathways in growth factor withdrawal, this metabolic contribution of autophagy did not appear critical for cell survival, as provision of exogenous pyruvate or lipids could not completely rescue Atg3-deficiency. Instead, autophagy suppressed a stress response that otherwise led to p53 phosphorylation and upregulation of p21 and the pro-apoptotic Bcl-2 family protein Puma. Importantly, BCR-Abl-expressing cells had low basal levels of autophagy but were highly dependent on this process, and rapidly underwent apoptosis upon disruption of autophagy through Atg3 deletion or treatment with chemical autophagy inhibitors. This dependence on autophagy extended in vivo, as Atg3 deletion also prevented BCR-Abl-mediated leukemogenesis in a cell transfer model. Together these data demonstrate a critical role for autophagy to mitigate cell stress, and that cells expressing the oncogenic kinase BCR-Abl appear particularly dependent on autophagy for cell survival and leukemogenesis.
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