Improving the metabolic efficiency of human T cells through AMPK agonist treatment

Abstract

BACKGROUND Adoptive immunotherapies are limited by the increased differentiation and metabolic exhaustion of the T cell product. The cellular energy sensor AMP-activated protein kinase (AMPK) controls many metabolic pathways. We hypothesized that increasing AMPK signaling during T cell expansion would create more metabolically efficient T cells. RESULTS Human T cells were stimulated in vitro, expanded with or without AMPK agonist A769662, and restimulated under varying glucose concentrations. Agonist treatment increased T cell expansion by manual cell counts (1.5× increase in cell number, p<0.01), and produced a higher percentage of CD62L+CD27+ cells by flow cytometry (10% increase, p<0.01). Twenty-four hours after re-stimulation, agonist-treated cells exhibited decreased basal oxygen consumption and extracellular acidification rates (45% and 20% decrease, p<0.001) but increased spare respiratory capacity (SRC) (97% increase, p<0.001). At 72 hours, control cells decreased proliferation in a glucose dose-dependent manner, as measured by BrDU uptake, whereas treated cells maintained a higher level of proliferation despite limited glucose availability. DISCUSSION Increasing AMPK signaling during T cell expansion improves doubling time while maintaining higher CD27 positivity, suggesting a greater yield of less differentiated cells. Upon re-stimulation, treated cells initiate less metabolic activity but maintain greater proliferation and SRC under glucose-limiting conditions. These results suggest that greater metabolic efficiency in agonist-treated cells allows for continued function despite nutrient restriction, a trait which could confer significant advantages to adoptive immunotherapies. Supported by grants from NIH (5K12 HD052892) and the St. Baldrick's Foundation (St. Baldrick's Fellowship Grant)