Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND 58105, USA.
School of Nursing, Jilin University, Changchun 130021, China.
Int J Mol Sci. 2023 Jun 30;24(13):10903. doi: 10.3390/ijms241310903.
Mechanisms by which BK (large-conductance calcium-sensitive potassium) channels are involved in vascular remodeling in hypertension are not fully understood. Vascular smooth muscle cell (VSMC) proliferation and vascular morphology were compared between hypertensive and normotensive rats. BK channel activity, protein expression, and interaction with IP3R (inositol 1,4,5-trisphosphate receptor) were examined using patch clamp, Western blot analysis, and coimmunoprecipitation. On inside-out patches of VSMCs, the Ca-sensitivity and voltage-dependence of BK channels were similar between hypertensive and normotensive rats. In whole-cell patch clamp configuration, treatment of cells with the IP3R agonist, Adenophostin A (AdA), significantly increased BK channel currents in VSMCs of both strains of rats, suggesting IP3R-BK coupling; however, the AdA-induced increases in BK currents were attenuated in VSMCs of hypertensive rats, indicating possible IP3R-BK decoupling, causing BK dysfunction. Co-immunoprecipitation and Western blot analysis demonstrated that BK and IP3R proteins were associated together in VSMCs; however, the association of BK and IP3R proteins was dramatically reduced in VSMCs of hypertensive rats. Genetic disruption of IP3R-BK coupling using junctophilin-2 shRNA dramatically augmented Ang II-induced proliferation in VSMCs of normotensive rats. Subcutaneous infusion of NS1619, a BK opener, to reverse BK dysfunction caused by IP3R-BK decoupling significantly attenuated vascular hypertrophy in hypertensive rats. In summary, the data from this study demonstrate that loss of IP3R-BK coupling in VSMCs induces BK channel dysfunction, enhances VSMC proliferation, and thus, may contribute to vascular hypertrophy in hypertension.
BK（大电导钙敏感钾）通道参与高血压血管重构的机制尚不完全清楚。比较了高血压和正常血压大鼠的血管平滑肌细胞（VSMC）增殖和血管形态。使用膜片钳、Western blot 分析和共免疫沉淀法检查 BK 通道活性、蛋白表达和与 IP3R（三磷酸肌醇受体）的相互作用。在 VSMC 的外翻膜片上，高血压和正常血压大鼠的 BK 通道的钙敏感性和电压依赖性相似。在全细胞膜片钳构型中，用 IP3R 激动剂 Adenophostin A（AdA）处理细胞可显著增加两种大鼠来源的 VSMC 中的 BK 通道电流，表明 IP3R-BK 偶联；然而，AdA 诱导的 BK 电流增加在高血压大鼠的 VSMC 中被减弱，表明可能的 IP3R-BK 解偶联，导致 BK 功能障碍。共免疫沉淀和 Western blot 分析表明，BK 和 IP3R 蛋白在 VSMC 中相互关联；然而，在高血压大鼠的 VSMC 中，BK 和 IP3R 蛋白的关联显著减少。使用 junctophilin-2 shRNA 基因敲除 IP3R-BK 偶联显著增强了正常血压大鼠 VSMC 中 Ang II 诱导的增殖。皮下输注 BK 开放剂 NS1619 以逆转 IP3R-BK 解偶联引起的 BK 功能障碍显著减轻了高血压大鼠的血管肥大。总之，这项研究的数据表明，VSMC 中 IP3R-BK 偶联的丧失导致 BK 通道功能障碍，增强 VSMC 增殖，从而可能导致高血压中的血管肥大。
