Functional blockade of the voltage-gated potassium channel Kv1.3 mediates reversion of T effector to central memory lymphocytes through SMAD3/p21cip1 signaling.

The maintenance of T cell memory is critical for the development of rapid recall responses to pathogens, but may also have the undesired side effect of clonal expansion of T effector memory (T(EM)) cells in chronic autoimmune diseases. The mechanisms by which lineage differentiation of T cells is controlled have been investigated, but are not completely understood. Our previous work demonstrated a role of the voltage-gated potassium channel Kv1.3 in effector T cell function in autoimmune disease. In the present study, we have identified a mechanism by which Kv1.3 regulates the conversion of T central memory cells (T(CM)) into T(EM). Using a lentiviral-dominant negative approach, we show that loss of function of Kv1.3 mediates reversion of T(EM) into T(CM), via a delay in cell cycle progression at the G2/M stage. The inhibition of Kv1.3 signaling caused an up-regulation of SMAD3 phosphorylation and induction of nuclear p21(cip1) with resulting suppression of Cdk1 and cyclin B1. These data highlight a novel role for Kv1.3 in T cell differentiation and memory responses, and provide further support for the therapeutic potential of Kv1.3 specific channel blockers in T(EM)-mediated autoimmune diseases.