Department of Pharmacology, and Cardiac & Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China; Department of Pharmacy, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China.
Department of Pharmacology, and Cardiac & Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.
J Mol Cell Cardiol. 2019 Sep;134:131-143. doi: 10.1016/j.yjmcc.2019.07.002. Epub 2019 Jul 10.
Cerebrovascular remodeling is the leading factor for stroke and characterized by increased extracellular matrix deposition, migration and proliferation of vascular smooth muscle cells, and inhibition of their apoptosis. TMEM16A is an important component of Ca-activated Cl channels. Previously, we showed that downregulation of TMEM16A in the basilar artery was negatively correlated with cerebrovascular remodeling during hypertension. However, it is unclear whether TMEM16A participates in angiotensin II (Ang II)-induced vascular remodeling in mice that have TMEM16A gene modification. In this study, we generated a transgenic mouse that overexpresses TMEM16A specifically in vascular smooth muscle cells. We observed that vascular remodeling in the basilar artery during Ang II-induced hypertension was significantly suppressed upon vascular smooth muscle-specific overexpression of TMEM16A relative to control mice. Specifically, we observed a large reduction in the deposition of fibronectin and collagen I. The expression of matrix metalloproteinases (MMP-2, MMP-9, and MMP-14), and tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) were upregulated in the basilar artery during Ang II-induced hypertension, but this was suppressed upon overexpression of TMEM16A in blood vessels. Furthermore, TMEM16A overexpression alleviated the overactivity of the canonical TGF-β1/Smad3, and non-canonical TGF-β1/ERK and JNK pathways in the basilar artery during Ang II-induced hypertension. These in vivo results were similar to the results derived in vitro with basilar artery smooth muscle cells stimulated by Ang II. Moreover, we observed that the inhibitory effect of TMEM16A on MMPs was mediated by decreasing the activation of WNK1, which is a Cl-sensitive serine/threonine kinase. In conclusion, this study demonstrates that TMEM16A protects against cerebrovascular remodeling during hypertension by suppressing extracellular matrix deposition. We also showed that TMEM16A exerts this effect by reducing the expression of MMPs via inhibiting WNK1, and decreasing the subsequent activities of TGF-β1/Smad3, ERK, and JNK. Accordingly, our results suggest that TMEM16A may serve as a novel therapeutic target for vascular remodeling.
脑血管重构是中风的主要因素，其特征是细胞外基质沉积增加、血管平滑肌细胞迁移和增殖，以及其凋亡受到抑制。TMEM16A 是钙激活氯离子通道的重要组成部分。之前，我们发现高血压时基底动脉 TMEM16A 的下调与脑血管重构呈负相关。然而，尚不清楚 TMEM16A 是否参与了血管紧张素 II（Ang II）诱导的 TMEM16A 基因修饰小鼠的血管重构。在这项研究中，我们生成了一种在血管平滑肌细胞中特异性过表达 TMEM16A 的转基因小鼠。我们观察到，与对照组小鼠相比，血管紧张素 II 诱导的高血压期间基底动脉的血管重构在血管平滑肌特异性过表达 TMEM16A 时明显受到抑制。具体而言，我们观察到纤维连接蛋白和 I 型胶原的沉积大量减少。在血管紧张素 II 诱导的高血压期间，基底动脉中基质金属蛋白酶（MMP-2、MMP-9 和 MMP-14）和金属蛋白酶组织抑制剂（TIMP-1 和 TIMP-2）的表达上调，但在血管中过表达 TMEM16A 时则受到抑制。此外，TMEM16A 的过表达减轻了血管紧张素 II 诱导的高血压期间基底动脉中经典 TGF-β1/Smad3 和非经典 TGF-β1/ERK 和 JNK 通路的过度活性。这些体内结果与体外用血管紧张素 II 刺激基底动脉平滑肌细胞得出的结果相似。此外，我们观察到 TMEM16A 通过降低 WNK1 的激活来抑制 MMPs 的抑制作用，WNK1 是一种 Cl 敏感的丝氨酸/苏氨酸激酶。总之，这项研究表明，TMEM16A 通过抑制细胞外基质沉积来防止高血压期间的脑血管重构。我们还表明，TMEM16A 通过抑制 WNK1 来降低 MMP 的表达，并降低随后的 TGF-β1/Smad3、ERK 和 JNK 活性，从而发挥这种作用。因此，我们的结果表明 TMEM16A 可能成为血管重构的新治疗靶点。
