CaN/NFAT信号通路介导的TRPC1-BK复合体功能失衡致高血压的机制研究

Hypertension is one of the most common cardiovascular diseases and an important cause of cardiovascular morbidity and mortality which may be involved by impaired function of ion channels. Transient receptor potential canonical (TRPC) channels and large conductance Ca2+-activated K+ (BK) channels are two important ion channels in vascular smooth muscle cells, which are widely appreciated in regulation of vascular contraction and relaxation. In the previous study, we have found that TRPC1 channels and BK channels form a complex which is regulated by CaN/NFAT signaling pathway in vascular smooth muscles cells. On the setting of our previous study results, we put forward the hypothesis that activation of CaN/NFAT pathway up-regulates the function of TRPC1 while down-regulates BK which induced imbalance of TRPC1-BK complex, leading to increased vascular tone and high blood pressure. To test this hypothesis, we will focus on the effects of TRPC1-BK complex regulated by CaN/NFAT signaling pathway on vascular function in hypertension from molecular, cellular, tissue and animal levels by applications of patch clamp technique, molecular biology technique, intracellular calcium concentration assay and vascular tone measurement in this study. The function of TRPC1-BK complex may be an important contributor to the vascular dysfunction in patients with hypertension and, as such, is potentially attractive target for therapeutic intervention.

高血压是最常见的心血管疾病之一，严重危害人类健康，其发生机制可能与血管平滑肌细胞离子通道功能异常有关。瞬时受体电位C1通道（TRPC1通道）和大电导钙激活钾通道（BK通道）是血管平滑肌细胞上两个重要离子通道，分别参与血管收缩和舒张。已有文献报道和申请者前期研究发现TRPC1通道和BK通道在血管平滑肌细胞上形成复合体（TRPC1-BK复合体），并受钙调神经磷酸酶/活化T细胞核因子（CaN/NFAT）信号通路调控。据此提出假说：正常情况下，TRPC1-BK复合体中TRPC1和BK通道功能相互平衡，而高血压时CaN/NFAT信号通路介导的TRPC1-BK复合体功能失衡，导致血管张力增加，血压升高。本课题拟采用膜片钳、分子生物学等实验技术，从分子、细胞、组织和动物整体水平探讨CaN/NFAT信号通路介导的TRPC1-BK复合体功能失衡致高血压的机制，研究结果可能为开拓高血压治疗新靶点具有重要意义。

高血压是最常见的心血管疾病之一，严重危害人类健康，其发生机制可能与血管平滑肌细胞离子通道功能异常有关。瞬时受体电位C1通道（TRPC1通道）和大电导钙激活钾通道（BK通道）是血管平滑肌细胞上两个重要离子通道，分别参与血管收缩和舒张。已有文献报道和申请者前期研究发现TRPC1通道和BK通道在血管平滑肌细胞上形成复合体（TRPC1-BK复合体），并受钙调神经磷酸酶/活化T细胞核因子（CaN/NFAT）信号通路调控。据此提出假说：正常情况下.，TRPC1-BK复合体中TRPC1和BK通道功能相互平衡，而高血压时CaN/NFAT信号通路介导的TRPC1-BK复合体功能失衡，导致血管张力增加，血压升高。为验证这一假说，本课题采用膜片钳、分子生物学等实验技术，从分子、细胞、组织和动物整体水平探讨CaN/NFAT信号通路介导的TRPC1-BK复合体功能失衡致高血压的机制，研究内容包括：① TRPC1通道和BK通道在结构和功能上形成复合体；② 高血压时TRPC1-BK复合体功能异常；③ CaN/ NFAT信号通路参与介导TRPC1-BK复合体的调控及机制。主要研究结果如下：①免疫共沉淀和免疫荧光实验证实TPRC1通道和BK通道以复合体结构存在于血管平滑肌细胞；② SHR大鼠肠系膜动脉平滑肌细胞BK通道电流密度降低；③ SHR大鼠肠系膜动脉平滑肌细胞内钙离子浓度较WKY组增高；④ SHR大鼠肠系膜动脉TRPC1通道蛋白表达较WKY组增加、BK-β1亚单位蛋白表达较WKY组减少，BK-α亚单位两组间无明显差异；⑤在KCl作用下，血管收缩达高峰后加入BK通道激活剂NS-1619，WKY组和SHR组肠系膜动脉均舒张，但WKY组肠系膜动脉舒张较SHR组明显；血管收缩达高峰后加入TRPC1通道抑制剂SKF96365，WKY组和SHR组肠系膜动脉均舒张，SHR组肠系膜动脉舒张较WKY组明显，提示高血压时血管舒缩障碍与TRPC1-BK复合体功能失衡相关；⑥高血压时，CaN/NFAT信号通路激活并介导TRPC1-BK复合体功能受损。本研究已发表论文5篇，其中SCI论文2篇，中华级论文3篇，研究结果可能对开拓高血压治疗新靶点具有重要意义。