心肌尔康通过调控Calpain/JP2改善横管重构和心力衰竭

Heart failure (HF) is a major chronic noncommunicable disease. Transverse tubule (TT) undergoes significant remodeling in HF and its stability depends on the integrity of the JP2 protein, which is tightly regulated by calpain. Previous studies showed that XJEK has a good effect on a variety of cardiovascular disease models (National Natural Science Foundation of China 81373774, 81073088). Recent studies have also shown that XJEK can improve myocardial function in myocardial infarction (MI) induced HF mice, but It is still not clear whether mediated by calpain/JP2 signal pathway. In summary, the scientific hypothesis is put forward: XJEK improves the post-MI TT remodeling and cardiac diastolic dysfunction by regulating the calpain/JP2 signaling pathway. In this study, XJEK is first used to observe the effects of XJEK on TT remodeling and calpain/JP2 in HF mice. Furthermore, it will be demonstrated that XJEK can inhibit the activity of calpain to retain JP2 integrity and improve TT remodeling, calcium homeostasis, and excitation-contraction coupling at the cellular level; It is further confirmed at the molecular level that XJEK can retain JP2 protein integrity by inhibiting calpain activity. This study will provide experimental evidence and modern medical explanations for the treatment of HF by XJEK.

心力衰竭（HF）是严重影响人群健康的重大非传染性慢病。横管系统（TT）在HF中发生明显重构，其稳定性依赖于JP2蛋白的完整，后者被calpain紧密调控。前期研究表明心肌尔康（XJEK）对多种心血管疾病模型有良好的疗效（国家自然科学基金81373774，81073088），新近研究更显示XJEK可改善心肌梗死（MI）诱导HF小鼠心功能，但是否通过calpain/JP2介导仍不清楚。综上提出科学假说：XJEK通过调控calpain/JP2信号通路改善MI后TT重构和心脏舒缩功能障碍。本研究首先在HF小鼠观察XJEK对TT重构、calpain/JP2的干预作用；进而在细胞水平证明XJEK可抑制calpain活性保留JP2完整，改善TT重构、钙稳态和兴奋收缩偶联；最后在分子水平进一步证实XJEK可通过抑制calpain活性保留JP2蛋白完整。该研究将为XJEK治疗HF提供实验依据和现代医学解释。

心血管疾病（cardiovascular disease, CVD）是包括高血压、急性冠状动脉综合征、慢性心衰等在内的一系列疾病的总称，已经成为威胁包括中国在内中低收入国家人民群众生命安全的一项重大公共卫生安全事件。中医药在减轻CVD治疗药物副作用、改善临床症状、提高生活质量、增加活动耐量、降低病死率和住院率、延缓甚至逆转病程进展等方面具有独特优势。根据本次申请获批项目任务书，我们在高盐饮食诱导高血压小鼠模型发现，心肌尔康能改善高盐饮食组小鼠高血压和心血管重构和肾功能障碍，同时可以逆转心脏组织Calpain1和JP2蛋白的异常表达，保护心肌细胞的膜耦联复合物（junctional membrane complex，JMC）的完整性。此外，我们在该动物模型上还发现心肌尔康实验治疗能明显改善内皮细胞功能紊乱、降低氧化应激水平、恢复促炎因子和抗炎因子之间的平衡，抑制内皮细胞间质化转变，从而改善心血管纤维化和靶器官损伤，证实了心肌尔康可从多靶点、多层面保护心血管，延缓和逆转CVD进展。中药药效物质基础是中医药继承、发展和创新的关键科学问题。我们采用高分辨LC-MS发现了15种来源于心肌尔康的移行入血成分，进一步我们利用Discovery Studio和Rossetta Ligand软件对移行成分逐个进行了分子对接，发现苦参碱可以通过氢键与JAK2的JH2催化位点稳定结合，从而增强JAK2激酶的活性。我们在动物和细胞损伤模型上观察到，经历缺血/再灌注或缺氧/复氧损伤后，细胞凋亡水平明显增加，给予苦参碱实验治疗后可明显增加p-STAT3/p-STAT1的比值，提高心肌组织的抗凋亡能力，从而发挥心脏保护作用。该研究方向深入的分子机制正在进一步深入开展中，也是申报2023年年国家自然科学基金重要的工作基础和研究策略。