%0 Journal Article
%T Potent Suppression of Kv1.3 Potassium Channel and IL-2 Secretion by Diphenyl Phosphine Oxide-1 in Human T Cells
%A Ning Zhao
%A Qian Dong
%A Li-Li Du
%A Xiao-Xing Fu
%A Yi-Mei Du
%A Yu-Hua Liao
%J PLOS ONE
%D 2013
%I Public Library of Science (PLoS)
%R 10.1371/journal.pone.0064629
%X Diphenyl phosphine oxide-1 (DPO-1) is a potent Kv1.5 channel inhibitor that has therapeutic potential for the treatment of atrial fibrillation. Many other Kv1.5 channel blockers also potently inhibit the Kv1.3 channel, but whether DPO-1 blocks Kv1.3 channels has not been investigated. The Kv1.3 channel is highly expressed in activated T cells, which is considered a favorable target for immunomodulation. Accordingly, we hypothesized that DPO-1 may exert immunosuppressive and anti-inflammatory effects by inhibiting Kv1.3 channel activity. In this study, DPO-1 blocked Kv1.3 current in a voltage-dependent and concentration-dependent manner, with IC50 values of 2.58 ¦ÌM in Jurkat cells and 3.11 ¦ÌM in human peripheral blood T cells. DPO-1 also accelerated the inactivation rate and negatively shifted steady-state inactivation. Moreover, DPO-1 at 3 ¦ÌM had no apparent effect on the Ca2+ activated potassium channel (KCa) current in both Jurkat cells and human peripheral blood T cells. In Jurkat cells, pre-treatment with DPO-1 for 24 h decreased Kv1.3 current density, and protein expression by 48¡À6% and 60¡À9%, at 3 and 10 ¦ÌM, respectively (both p<0.05). In addition, Ca2+ influx to Ca2+-depleted cells was blunted and IL-2 production was also reduced in activated Jurkat cells. IL-2 secretion was also inhibited by the Kv1.3 inhibitors margatoxin and charybdotoxin. Our results demonstrate for the first time that that DPO-1, at clinically relevant concentrations, blocks Kv1.3 channels, decreases Kv1.3 channel expression and suppresses IL-2 secretion. Therefore, DPO-1 may be a useful treatment strategy for immunologic disorders.
%U http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0064629