Inhibition of distinct glycolytic enzymes produces differential effects on CD4 T cell function

Abstract

Abstract Background When T cells are activated, they upregulate glycolysis and take on a requisite Warburg phenotype. In this study, we evaluated the effect of inhibiting two distinct glycolytic enzymes, GAPDH and PGAM, on CD4 T cell differentiation and effector activities in order to gain a mechanistic understanding of the relationship between glycolysis and T cell function. Methods To evaluate the effect of GAPDH inhibition on T cell function, we cultured naïve murine CD4+ T cells under Th1 or Treg polarizing conditions and treated with either the GAPDH inhibitor heptelidic acid or the PGAM inhibitor EGCG. We then assessed either IFNγ production or identified CD25+Foxp3+ cells in response to either Th1 or Treg polarization, respectively. To evaluate the impact of GAPDH inhibition in vivo, we used the MOG35–55 experimental autoimmune encephalomyelitis (EAE) mouse model of multiple sclerosis (MS) and compared neurological function in mice treated with vehicle or heptelidic acid. Results We found that GAPDH inhibition had a potent anti-inflammatory effect on T cells in vitro, drastically reducing IFNγ production at both the transcriptional and protein levels. Interestingly, PGAM inhibition had the opposite effect, potently blocking Treg differentiation. In the EAE mouse model of MS, heptelidic acid attenuated the disease course, indicating that GAPDH inhibition is anti-inflammatory in vivo. Discussion GAPDH inhibition was anti-inflammatory in vitro and in vivo, while PGAM inhibition had the opposite effect. These findings suggest that the functional consequences of glycolysis inhibition depend on the specific enzymes targeted, which has both mechanistic and therapeutic implications for the role of glycolysis in immune cell function.