LAUSR

Purpose Studies of negative ionotropic effects of IL‐2 create the basis for possible IL‐2 impact on nonselective conductance (GNS), which potentially makes these effects useful in elucidation of the pathways affected by IL‐2. Materials and methods A culture of human cardiac fibroblasts (CHCFs) was used in this study. A voltage clamp mode of the whole‐cell patch‐clamp technique was introduced. The level of phosphorylated NF‐&kgr;B was determined by newly developed semi‐quantitative ELISA. Results The IL‐2 (5 ng/ml) increased the currents during the depolarizing clamp to larger amplitudes without changing their time course. In the CHCFs pretreated with 50 &mgr;mol/L 2‐APB, IL‐2‐induced increase in GNS was highly prevented (p < 0.001), indicating possible STIM‐ORAI involvement. The CHCF perfusion with IL‐2 in the presence of IMD‐0354 for 14–16 min confirmed a significant GNS prevention (between 50 and 80%), indicating I&kgr;B involvement in the IL‐2‐induced signaling. The CHCF perfusion with IL‐2 in the presence of Chel, induced significant prevention in the GNS expression (between 50 and 80%) compared to IL‐2 treated cells, indicating PKC involvement. Conclusions IL‐2 mediated GNS increase is mediated by activation of downstream players such as PKC, I&kgr;B, and NF‐&kgr;B, which are probably further responsible for the upregulation of STIM‐ORAI. HighlightsIn human cardiac fibroblasts, IL‐2 increased GNS via PKC, I&kgr;B and NF‐&kgr;B.IL‐2‐induced GNS is probably a reflection of IL‐2‐induced STIM‐ORAI.IL‐2‐induced STIM‐ORAI through degradation of I&kgr;B and its dissociation from the NF‐&kgr;B