巨噬细胞移动抑制因子对HL-1细胞T型钙电流的调控

Regulation of macrophage migration inhibitory factor on T-type calcium channels in HL-1 cells

目的观察巨噬细胞移动抑制因子(macrophage migration inhibitory factor,MIF)对心房肌细胞T型钙电流(T-type calcium channel current,ICa,T)的调控。方法使用全细胞膜片钳和分子生物分析方法检测心房肌细胞ICa,T的表达。结果在体外培养的心房肌细胞株(HL-1细胞)中,小鼠重组MIF(20、40 nmol/L,24 h)可明显抑制I Ca,T的峰值电流,与对照组比较,差异均有统计学意义[峰值内向电流:(-17.5±2.9)pA/pF vs.(-27.9±3.4)pA/pF,P<0.05;(-11.3±1.7)pA/pF vs.(-27.9±3.4)pA/pF,P<0.01];并可损伤电压依赖的I Ca,T激活,使T型钙通道α1G和α1H亚单位mRNA表达下调。而Src非特异性抑制剂genistein和特异性抑制剂PP1可逆转40 nmol/L MIF所致的I Ca,T下调[genistein:(-11.3±1.7)pA/pF vs.(-16.1±0.8),P<0.05;PPI:(-11.3±1.7)pA/pF vs.(-19.0±3.2)pA/pF,P<0.05]。结论MIF可能通过影响I Ca,T参与心房颤动的病理过程,Src可能参与该信号转导途径。

Objectives To investigate the role of macrophage migration inhibitory factor （MIF） in the regulation of Ttype calcium channels （Ica,T） in atrial myocytes.Methods The whole-cell voltage-clamp technique and biochemical assays were used to detect the regulation of ICa,T in atrial myocytes.Results In atrium-derived myocytes （HL-1 cells） cultured in vitro,mouse recombinant MIF （20 or 40 nmol/L,24 h） could significantly suppress peak ICa,T when compared with control group [（-17.5±2.9） pA/pF vs.（-27.9±3.4） pA/pF,P〈0.05; （-11.3±1.7） pA/pF vs.（-27.9±3.4）pA/pF,P〈0.01],impair the voltage-dependent activation of ICa,T and down-regulate the expressions of α1G and α1H mRNA of T-type calcium channels.The reduction of ICa,T induced by 40 nmol/L recombinant MIF could be reversed by genistein and PP1 [genistein：（-11.3±1.7） pA/pF vs.（-16.1±0.8）,P〈0.05; PPI：（-11.3±1.7） pA/pF vs.（-19.0±3.2） pA/pF,P〈0.05].Conclusions MIF may be involved in the pathogenesis of atrial fibrillation by affecting the ICa,T in atrium-derived myocytes,in which Src may take part in the signal transduction pathway.