IL-4-induced upregulation of adenine nucleotide translocase 3 and its role in Th cell survival from apoptosis

We have identified mitochondrial adenine nucleotide translocase (ANT)3 as a novel target up-regulated by IL-4 in human T cells. The IL-4-induced ANT3 expression is dependent on tyrosine kinase, NF-kappaB, PI3K/Akt, and Erk pathways. In fact, IL-4 induced specific activation of NF-kappaB, Akt, and Erk in Jurkat T cells and partially rescued these cells from dexamethasone-induced apoptosis. The IL-4-mediated T cell survival was blocked by inhibitors of tyrosine kinase, NF-kappaB, PI3K/Akt, and Erk. During the IL-4-induced T cell rescue, there was a concomitant increase in ANT3, nuclear NF-kappaB, and Bcl-2 and a decrease in ANT1, I-kappaB, and mitochondrial Bax-alpha levels. Importantly, overexpression of ANT3 effectively protected T cells from dexamethasone-induced apoptosis, while forced expression of ANT1 caused apoptosis. In contrast, siRNA knock-out of ANT3 expression induced T cell apoptosis and blocked the IL-4-mediated cell survival. Together these results suggest that ANT3 has a potential role in Th cell survival and immune cell homeostasis.