The effect of 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  include upregulation of genes associated with DNA damage response and pro- and anti-apoptotic pathways and downregulation of genes involved in cell cycling, DNA replication, mRNA splicing, and ribosome biogenesis. The majority of the affected processes require iron as a co-factor. 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 200 mM ERG245 (BCAT1 inhibitor). The beads were subsequently removed and cells were collected.