Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.
Department of Physiology, Nanjing Medical University, Nanjing, Jiangsu, China.
Cell Mol Life Sci. 2024 Apr 4;81(1):164. doi: 10.1007/s00018-024-05198-z.
Diabetic hyperglycemia induces dysfunctions of arterial smooth muscle, leading to diabetic vascular complications. The Ca1.2 calcium channel is one primary pathway for Ca influx, which initiates vasoconstriction. However, the long-term regulation mechanism(s) for vascular Ca1.2 functions under hyperglycemic condition remains unknown. Here, Sprague-Dawley rats fed with high-fat diet in combination with low dose streptozotocin and Goto-Kakizaki (GK) rats were used as diabetic models. Isolated mesenteric arteries (MAs) and vascular smooth muscle cells (VSMCs) from rat models were used to assess K-induced arterial constriction and Ca1.2 channel functions using vascular myograph and whole-cell patch clamp, respectively. K-induced vasoconstriction is persistently enhanced in the MAs from diabetic rats, and Ca1.2 alternative spliced exon 9* is increased, while exon 33 is decreased in rat diabetic arteries. Furthermore, Ca1.2 channels exhibit hyperpolarized current-voltage and activation curve in VSMCs from diabetic rats, which facilitates the channel function. Unexpectedly, the application of glycated serum (GS), mimicking advanced glycation end-products (AGEs), but not glucose, downregulates the expression of the splicing factor Rbfox1 in VSMCs. Moreover, GS application or Rbfox1 knockdown dynamically regulates alternative exons 9* and 33, leading to facilitated functions of Ca1.2 channels in VSMCs and MAs. Notably, GS increases K-induced intracellular calcium concentration of VSMCs and the vasoconstriction of MAs. These results reveal that AGEs, not glucose, long-termly regulates Ca1.2 alternative splicing events by decreasing Rbfox1 expression, thereby enhancing channel functions and increasing vasoconstriction under diabetic hyperglycemia. This study identifies the specific molecular mechanism for enhanced vasoconstriction under hyperglycemia, providing a potential target for managing diabetic vascular complications.
糖尿病性高血糖会导致动脉平滑肌功能障碍，从而引发糖尿病血管并发症。Ca1.2 钙通道是 Ca 内流的主要途径之一，它启动血管收缩。然而，高血糖状态下血管 Ca1.2 功能的长期调节机制尚不清楚。在这里，我们使用高脂肪饮食联合小剂量链脲佐菌素和 Goto-Kakizaki（GK）大鼠构建的糖尿病模型来研究这一问题。使用血管张力测定仪和全细胞膜片钳技术分别检测大鼠模型分离的肠系膜动脉（MAs）和血管平滑肌细胞（VSMCs）中的 K 诱导的动脉收缩和 Ca1.2 通道功能。结果发现，糖尿病大鼠的 MAs 中 K 诱导的血管收缩持续增强，同时 Ca1.2 剪接外显子 9增加，而外显子 33 减少。此外，糖尿病大鼠 VSMCs 中的 Ca1.2 通道表现出超极化的电流-电压和激活曲线，这有助于通道功能。出乎意料的是，糖基化血清（GS）的应用，模拟了晚期糖基化终产物（AGEs），而不是葡萄糖，下调了 VSMCs 中的剪接因子 Rbfox1 的表达。此外，GS 的应用或 Rbfox1 的敲低会动态调节外显子 9和 33，导致 Ca1.2 通道在 VSMCs 和 MAs 中的功能增强。值得注意的是，GS 增加了 VSMCs 中 K 诱导的细胞内钙离子浓度和 MAs 的血管收缩。这些结果表明，AGEs，而不是葡萄糖，通过降低 Rbfox1 的表达来长期调节 Ca1.2 剪接事件，从而增强高血糖状态下的通道功能并增加血管收缩。本研究确定了高血糖状态下增强血管收缩的特定分子机制，为糖尿病血管并发症的治疗提供了潜在的靶点。
