Entry of glucose- and glutamine-derived carbons into the citric acid cycle supports early steps of HIV-1 infection in CD4 T cells

The susceptibility of CD4 T cells to human immunodeficiency virus 1 (HIV-1) infection is regulated by glucose and glutamine metabolism, but the relative contributions of these nutrients to infection are not known. Here we show that glutaminolysis is the major pathway fuelling the tricarboxylic acid (TCA) cycle and oxidative phosphorylation (OXPHOS) in T-cell receptor-stimulated naïve, as well as memory CD4, subsets and is required for optimal HIV-1 infection. Under conditions of attenuated glutaminolysis, the α-ketoglutarate (α-KG) TCA rescues early steps in infection; exogenous α-KG promotes HIV-1 reverse transcription, rendering both naïve and memory cells more sensitive to infection. Blocking the glycolytic flux of pyruvate to lactate results in altered glucose carbon allocation to TCA and pentose phosphate pathway intermediates, an increase in OXPHOS and augmented HIV-1 reverse transcription. Moreover, HIV-1 infection is significantly higher in CD4 T cells selected on the basis of high mitochondrial biomass and OXPHOS activity. Therefore, the OXPHOS/aerobic glycolysis balance is a major regulator of HIV-1 infection in CD4 T lymphocytes.