【摘要】 目的 探讨转录辅激活因子p300是否参与调控心房肌细胞Kv1.5蛋白的表达。方法 以Western Blot检测细胞和C57BL/6小鼠心房组织p300蛋白、钾离子通道蛋白Kv1.5的表达。HL-1细胞在血管紧张素Ⅱ（AngⅡ）刺激的基础上使用p300抑制剂姜黄素或p300 siRNA干预，观察p300对Kv1.5蛋白表达以及超速延迟整流钾电流(I_kur)的作用。全细胞膜片钳技术检测各组细胞的I_kur和动作电位时程（APD）。快速起搏心房观察小鼠心房颤动（房颤）的可诱发性。结果 动物实验显示，与对照组相比，AngⅡ处理组小鼠有着明显更高的房颤诱发率（P<0.01），心耳组织p300以及Kv1.5蛋白表达明显升高（均P<0.05），而姜黄素干预后可以明显减少小鼠的房颤诱发率（P<0.01），并使p300和Kv1.5蛋白表达减少（P<0.05）。细胞实验显示，和对照组相比，AngⅡ处理组HL-1细胞p300以及Kv1.5蛋白表达明显升高（P<0.05）,I_kur电流密度上升，APD缩短。在分别用p300抑制剂姜黄素和p300 siRNA干预后表现为p300和Kv1.5蛋白表达减少（P<0.05）,I_kur电流密度下降，APD延长。结论 AngⅡ可通过p300引起心房肌细胞Kv1.5蛋白表达上升，I_kur电流密度上升，引起心房肌细胞电重构。更多还原

【Abstract】 Objective To investigate whether transcriptional co-activator p300participates in the regulation of Kv1.5 expression in atrial myocytes.Methods Western Blot was used to determine the expression levels of Kv1.5 and p300 in the cell and C57BL/6 mice atrial tissues.Based on the treatment of angiotensinⅡ（AngⅡ），curcumin,an inhibitor of p300,as well as p300 siRNA was used to investigate its functional effect on expression of Kv1.5 and current density of ultra-rapid delayed rectifier K（+）current(I_kur).Whole-cell-patch-clamp was to record the current density of atrial-specific I_kur and action potential duration（APD）.The susceptibility of atrial fibrillation was detected by electrophysiological examination.Results The incidence of AF was significantly higher in AngⅡ-treated mice（P<0.01）and could be suppressed by curcumin（P<0.01）.In the LA tissues from AngⅡ-treated mice,p300 and Kv1.5protein expression increased（both P<0.05）,and these changes could be reversed by curcumin（P<0.05）.Expression of p300 and Kv1.5 was significantly increased in angiotensinⅡ-treated HL-1 cell compared with control group（P<0.05）.The results of whole-cell-patch clamp showed that angiotensinⅡ-treated HL-1 had higher I_kur current density and shorter APD compared with control group（P<0.01）.However,p300 inhibitor curcumin could restored I_kur,APD and expression of Kv1.5 induced by angiotensinⅡ（P<0.05）.The same results were also found when p300 was gene-silenced with siRNA.Conclusions AngiotensinⅡinduces Kv1.5 upregulation via co-activator p300 in atrial myocytes.Inhibition of p300 may be beneficial for atrial fibrillation treatment by abrogate the upregulation of Kv1.5 induced by angiotensinⅡ.更多还原