冠状动脉对酸中毒的过度收缩归因于动脉平滑肌细胞中 TMEM16A/ANO1 的活性更高。

Coronary hypercontractility to acidosis owes to the greater activity of TMEM16A/ANO1 in the arterial smooth muscle cells.

机构信息

Department of Pharmacology, Shanxi Medical University, Xinjiannanlu 56, Taiyuan 030001, Shanxi Province, China.

出版信息

Biomed Pharmacother. 2021 Jul;139:111615. doi: 10.1016/j.biopha.2021.111615. Epub 2021 May 7.

DOI:10.1016/j.biopha.2021.111615

PMID:34243598

Abstract

BACKGROUND

Severe acidosis deteriorates cardiac injury. Rat coronary arteries (RCAs) are unusually hypercontractive to extracellular (o) acidosis (EA). TMEM16A-encoded anoctamin 1 (ANO1), a Ca-activated chloride channel (CaCC), plays an important role in regulating coronary arterial tension.

PURPOSE

We tested the possibility that the activation of CaCCs in the arterial smooth muscle cell (ASMC) contributes to EA-induced RCA constriction.

METHODS

ANO1 expression was detected with immunofluorescence staining and Western blot. TMEM16A mRNA was assessed with quantitative Real-Time PCR. Cl currents and membrane potentials were quantified with a patch clamp. The vascular tension was recorded with a myograph. Intracellular (i) level of Cl and Ca was measured with fluorescent molecular probes.

RESULTS

ANO1 was expressed in all tested arterial myocytes, but was much more abundant in RCA ASMCs as compared with ASMCs isolated from rat cerebral basilar, intrarenal and mesenteric arteries. EA reduced [Cl] levels, augmented CaCC currents exclusively in RCA ASMCs and depolarized RCA ASMCs to a greater extent. Cl deprivation, which depleted [Cl] by incubating the arteries or their ASMCs in Cl-free bath solution, decreased EA-induced [Cl] reduction, diminished EA-induced CaCC augmentation and time-dependently depressed EA-induced RCA constriction. Inhibitor studies showed that these EA-induced effects including RCA constriction, CaCC current augmentation, [Cl] reduction and/or [Ca] elevation were depressed by various Cl channel blockers, [Ca] release inhibitors and L-type voltage-gated Ca channel inhibitor nifedipine. ANO1 antibody attenuated all observed changes induced by EA in RCA ASMCs.

CONCLUSION

The greater activity of RCA ASMC CaCCs complicated with an enhanced Ca mobilization from both [Ca] release and [Ca] influx plays a pivotal role in the distinctive hypercontractility of RCAs to acidosis. Translation of these findings to human beings may lead to a new conception in our understanding and treating cardiac complications in severe acidosis.

摘要

背景

严重酸中毒可使心脏损伤恶化。大鼠冠状动脉（RCAs）对细胞外（o）酸中毒（EA）异常强烈收缩。TMEM16A 编码的钙激活氯离子通道（CaCC）anoctamin 1（ANO1）在调节冠状动脉张力方面发挥着重要作用。

目的

我们检测了动脉平滑肌细胞（ASMC）中 CaCC 的激活是否有助于 EA 诱导的 RCA 收缩。

方法

通过免疫荧光染色和 Western blot 检测 ANO1 的表达。用实时定量 PCR 检测 TMEM16A mRNA。用膜片钳技术量化 Cl 电流和膜电位。用肌动描记器记录血管张力。用荧光分子探针测量细胞内（i）Cl 和 Ca 水平。

结果

ANO1 在所有测试的动脉肌细胞中表达，但在 RCA ASMC 中的表达明显高于从大鼠脑基底动脉、肾内动脉和肠系膜动脉分离的 ASMC。EA 降低了[Cl]水平，仅在 RCA ASMC 中增加了 CaCC 电流，并使 RCA ASMC 去极化程度更大。Cl 剥夺通过在 Cl 缺失浴液中孵育动脉或其 ASMC，耗竭 [Cl]，降低 EA 诱导的[Cl]减少，减少 EA 诱导的 CaCC 增强，并随时间推移抑制 EA 诱导的 RCA 收缩。抑制剂研究表明，这些 EA 诱导的效应，包括 RCA 收缩、CaCC 电流增强、[Cl]减少和/或[Ca]升高，被各种 Cl 通道阻滞剂、[Ca]释放抑制剂和 L 型电压门控 Ca 通道抑制剂硝苯地平抑制。ANO1 抗体减弱了 EA 在 RCA ASMC 中引起的所有观察到的变化。