Metformin and 2-Deoxyglucose Collaboratively Suppress Human CD4+ T Cell Effector Functions and Activation-Induced Metabolic Reprogramming

Metabolic reprogramming plays a central role in T cell activation and differentiation, and the inhibition of key metabolic pathways in activated T cells represents a logical approach for the development of new therapeutic agents for treating autoimmune diseases. The widely prescribed antidiabetic drug metformin and the glycolytic inhibitor 2-deoxyglucose (2-DG) have been used to study the inhibition of oxidative phosphorylation and glycolysis, respectively, in murine immune cells. Published studies have demonstrated that combination treatment with metformin and 2-DG was efficacious in dampening mouse T cell activation-induced effector processes, relative to treatments with either metformin or 2-DG alone. In this study, we report that metformin + 2-DG treatment more potently suppressed IFN-gamma production and cell proliferation in activated primary human CD4(+) T cells than either metformin or 2-DG treatment alone. The effects of metformin + 2-DG on human T cells were accompanied by significant remodeling of activation-induced metabolic transcriptional programs, in part because of suppression of key transcriptional regulators MYC and HIF-1A. Accordingly, metformin + 2-DG treatment significantly suppressed MYC-dependent metabolic genes and processes, but this effect was found to be independent of mTORC1 signaling. These findings reveal significant insights into the effects of metabolic inhibition by metformin + 2-DG treatment on primary human T cells and provide a basis for future work aimed at developing new combination therapy regimens that target multiple pathways within the metabolic networks of activated human T cells.