MiRP1对异源转染的CHO细胞上HCN1和HCN2通道电生理特性的调节

MiRP1 regulates electrophysiological properties of HCN1 and HCN2 in CHO cells in vitro

目的评价Mink相关肽1(MiRP1)对异源转染的CHO细胞上的HCN1、HCN2通道电生理特性的影响。方法将MiRP1质粒DNA分别和HCN1、HCN2质粒DNA共转染CHO-K1细胞,用全细胞膜片钳记录细胞膜上的HCN通道电流。结果MiRP1显著增加HCN2[(37.8±4.8)pA/pF(n=11)vs(25.9±1.7)pA/pF(n=10);-140 mV,P<0.05]的电流密度,但是对HCN1的电流大小没有影响[(41.3±10.9)pA/pF(n=13)vs(34.9±7.8)pA/pF(n=11);P>0.05];MiRP1可加快HCN1[时间常数:(180.9±8.6)msvs(306.1±45.6)ms;-80 mV,P<0.05]和HCN2[时间常数:(391.8±33.6)msvs(763.5±106.1)ms;-80 mV,P<0.05]激活动力学;MiRP1对HCN1及HCN2通道激活的电压依赖性没有影响。结论MiRP1可加快HCN1和HCN2通道激活,且增加HCN2的电流表达。

Objective To investigate the modulation of electrophysiological properties of hyperpolarizationactivated cyclic nucleotide-gated channels （HCN） HCN1 and HCN2 by transfecting MinK-related peptide 1 （MiRP1） in Chinese hamster ovarian （CHO） cells. Methods CHO cells were co-transfected with plasmid DNA encoding either of the cardiac HCN isoforms （HCN1, HCN2） with MiRP1 to observe the effect of MiRP1 on HCN whole-cell currents. Whole-cell patch clamp technique was used to record the 2 channel currents of the transfected cells. Results MiRP1 significantly increased whole-cell current density of HCN2 [ （37.8 ±4.8 ） pA/pF（n = 11 ） vs control （25.9 ±1.7） pA/pF（n = 10） ; at - 140 mV, P 〈 0.05 ], while not affecting HCN1 current density [ （41.3 ±10.9） pA/pF（ n = 13 ） vs control （34.9 ±7.8） pA/pF（ n = 11 ） ; P 〉 0. 05 ]. Moreover, MiRP1 accelerated the activation kinetic of HCN1 [ tau （ 180.9 ±8.6 ） ms vs control （ 306. 1 ±45.6） ms; at -80 mV, P〈0.05] and HCN2 [tau （391.8 ±33.6） ms vs control （763.5 ±106. 1） ms; at -80 mV, P 〈0. 05 ]. But MiRP1 did not affect voltage dependence of HCN1 and HCN2 channel activation. Conclusion MiRP accelerates HCN1 or HCN2 channel activation kinetics, and leads to increase of HCN2 current density.