Interleukin-6 induced activation of a non-selective outward cation conductance in human cardiac fibroblasts

Abstract

Background: It has been demonstrated that cardiac fibroblasts of the human heart have several myocyte-like features, induced by inflammation.

Objectives: This study analyzed the changes of the expressed currents in the basal condition and in the presence of interleukin-6 in cultured human cardiac fibroblasts.

Methods: Human cardiac fibroblasts were cultured as monolayers from earlier passages (2-4). Whole-cell voltage clamp experiments were performed on single culture human cardiac fibroblasts.

Results: The cultured human cardiac fibroblasts had a membrane resistance of R_m of 412±91MΩ, and a resting membrane potential of -68.1±3.2mV. Among different cells, we have been analyzed these at which depolarizing clamp steps induced outward currents that reached peak within approx. 20ms and then slowly decayed. Gd³⁺ decreased the current amplitudes at depolarizing steps. Superfusion with interleukin-6 caused increasing of the outward membrane currents. The changes in the membrane currents continued up to 6min of interleukin-6 perfusion, by reaching their maximum at 3min and slowly decreasing to the level of control recordings at 6min. In the presence of 8μmol/l Gd³⁺, interleukin-6 does not modify the membrane currents.

Conclusion: The involvement of mechano sensitive channels in interleukin-6 induced electrical property of fibroblast was proposed. This report presents one particular model of action of interleukin-6, that can open new insights for a deeper understanding of the relationships between interleukin-6 and different ion channels into the fibroblast.

Keywords: Cultured human cardiac fibroblasts; Interleukin-6; Ion currents.