Alcohol-sourced acetate impairs T cell function by promoting cortactin acetylation

Alcohol is among the most widely consumed dietary substances. While excessive alcohol consumption damages the liver, heart and brain, clinical observations also suggest that alcohol has strong immunoregulatory properties. However, little is known about the mechanistic effects of alcohol on the immune system. T cell functions such as migration, immune synapse formation and activation depend on the reorganization of the cytoskeleton. In this study, we show that acetate, the metabolite of alcohol, effectively inhibits the migratory capacity of T cells through increased tissue acetate levels that lead to acetylation of cortactin, a protein that binds filamentous actin and facilitates branching. Current knowledge of cortactin’s role in T cells is limited. Here we demonstrate and confirm that primary mouse and human T cells express cortactin and acetylation of cortactin inhibits actin filament binding leading to reduced filament branching, lamellipodia formation and T cell migration. Mutated acetylation-resistant cortactin rescued the acetate-induced inhibition of T cell migration. Primary mouse cortactin knock-out T cells exhibited severely reduced T cell migration. Furthermore, acetate-induced cytoskeletal changes effectively inhibited activation, proliferation, and immune synapse formation in T cells exposed to acetate at tissue concentrations reached by alcohol consumption. In summary, these data show that acetate, the key metabolite of alcohol, is inhibiting T cell mediated immune responses by modulating the biomechanics of T cells through their cytoskeletal function.