The effect of temporal BCAT1 inhibition on activated human CD8+ T cells

Branched chain amino acid transaminase 1 (BCAT1) moderates iron balance during CD8+ T cell activation by limiting the conversion of iron regulatory protein 1 (IRP1) to aconitase 1 (ACO1). BCAT1 inhibition (BCAT1i) increases ACO1 activity, prevents iron uptake by activated CD8+ T cells, increases iron-sulfur (Fe-S) clusters in the mitochondria, arrests the timely degradation of nuclear ACO1, and inhibits CD8+ T cell differentiation in vitro and in vivo. The effects of BCAT1i on CD8+ T cell activation are reversible and temporal BCAT1i yields CD8+ T cells with increased effector functions. CD8+ T cells, which were activated in the presence of ERG245 (BCAT1 inhibitor) for 24h and cultured for an additional 48h without it, upregulated genes that support bioenergetics processes such as OXPHOS, glycolysis, FA metabolism. Overall design: CD8+ T cells were isolated from the peripheral blood of 3 individual donors. Approximately 3x106 cells were activated with anti-CD3/anti-CD28 Dynabeads for 24h in the presence or absence of 100 mM ERG245. The beads were subsequently removed, media were replenished with complete RPMI media, and the cells were cultured for and additional 48h. The cells were collected 72 hrs after initiation of activation.