夏桂玲，胥亚楠，杨龙，李隽，何炯红，邓娜，田龙海，田银



血管紧张素受体1型-钙调神经磷酸酶信号通路对肥大乳鼠心房肌细胞瞬时外向钾电流离子通道重构的调控作用

夏桂玲，胥亚楠，杨龙，李隽，何炯红，邓娜，田龙海，田银

摘要

目的： 探讨血管紧张素受体1型（AT1）-钙调神经磷酸酶（Calcineurin；CaN）信号通路对肥大乳鼠心房肌细胞瞬时外向钾电流（Ito）离子通道重构的调控作用。

方法：分离1天龄乳大鼠心房肌细胞，培养24 h分组：①对照组：不予牵张刺激；②牵张组：牵张增加12%硅胶模面积，培养24 h；③替米沙坦组：替米沙坦 1 μmol/L干预1 h，继之牵张24 h；④环孢素A（CsA）组：CsA 0.25 μg/ml干预1 h，继之牵张24 h。定量分析牵张组与对照组细胞蛋白/DNA比值、心房钠尿肽（ANP） mRNA表达鉴定细胞肥大。全细胞膜片钳技术检测细胞Ito的变化。蛋白免疫印迹法检测Ito离子通道α亚单位Kv4.3和CaNA亚基的蛋白表达。

结果：牵张组较对照组，Ito电流密度显著降低；Kv4.3蛋白表达下调、促进CaNA蛋白表达；与牵张组比较，替米沙坦组和CSA组明显抑制牵张刺激上述反应。

结论：AT1-CaN信号通路参与调控肥大乳鼠心房肌细Ito离子通道重构。

关键词 受体, 血管紧张素, 1型； 离子通道；信号转导；钙调神经磷酸酶

资助项目：国家自然科学基金（81260040；81060018）；贵州省科学技术基金[黔科合J字 （2012）2239号]

Objective: To explore the role of angiotensin receptor type I (AT1)-calcineurin (CaN) signaling pathway in transient outward potassium ion channel (Ito) remolding in hypertrophic atrial myocytes of neonatal rats.

Methods: 1 day old neonatal rats’ atrial myocytes were isolated and the cells were divided into 4 groups:①Control group, normal cells were cultured for 24 h, ②Stretching group, the cells were cultured for 24 h with mechanical stretching to induce hypertrophy, ③Telmisartan group, the cells were treated by telmisartan at 1 μmol/L for 1 h, then cultured for 24 h and ④Cyclosporin-A (CsA) group, the cells were treated by CsA at 0.25 μg/ml for 1 h, then cultured for 24 h. The ratios of protein/DNA in myocytes were compared between Control group and Stretching group, cell hypertrophy was defined by mRNA expression of atrial natriuretic peptide (ANP). Ito changes were detected by whole-cell patch clamping technique, proteins expressions of Kv4.3 and CaN A subunit were examined by Western blot analysis.

Results: Compared with Control group, Stretching group showed obviously decreased Ito density and Kv4.3 protein expression, while increased CaN A protein expression; Compared with Stretching group, the above effects were reduced in Telmisartan group and CsA group.

Conclusion: AT1-CaN signaling pathway was involved in the regulation of Ito channel remodeling in hypertrophic atrialmyocytes of neonatal rats.

Key words Receptors, angiotensin type I; Ion channels; Signaling transduction; remodeling; Calcineurin

(Chinese Circulation Journal, 2016,31:398.)

心房重构在心房颤动（房颤）发生、发展及维持中起着重要作用，其主要包括心房电重构和结构重构[1]。心房肌细胞离子通道重构是心房电重构的基础之一。钙调神经磷酸酶（ CaN）在牵张刺激致心房肌细胞肥大的病理生理过程中发挥着重要作用，在房颤患者心房肌组织表达增加、活性增强[2]；……