Tiam1调节心肌肥厚的作用及机制研究

The mechanism of cardiac hypertrophy is the core of the treatment of heart failure. We found that Tiam1 gene knockout can significantly alleviate the decrease in left ventricular ejection fraction and cardiac hypertrophy, but the specific mechanism is unknown. Based on the list of candidate proteins, including EphA2, that have been screened and have potential to interact with Tiam1, we are planning to use the Tiam1 gene knockout and transgenic mice, and adenovirus transfection to elucidate the role of Tiam1 in cardiac hypertrophy and heart failure and explore the common molecular signaling pathway via animal and cell experiments. Furthermore, high-performance liquid chromatography/tandem mass spectrometry is used to search for the specific target of Tiam1 in cardiomyocytes. Combined with immunoprecipitation and molecular cloning techniques, the interaction between them is discussed. We then constructs transgenic or knockout mice with interacting proteins, and continue to observe the therapeutic or reversal effects of interfering with specific targets on cardiac hypertrophy. The aim of this study is to elucidate the role and molecular mechanism of Tiam1 in cardiac hypertrophy, especially to find the specific role of Tiam1 interacting protein in cardiomyocytes, which provides a new molecular target for the prevention and treatment of cardiac hypertrophy and heart failure.

阐明心肌肥厚的调控机制是治疗心力衰竭的核心。我们前期发现Tiam1基因敲除可以明显缓解TAC导致的左室射血分数下降及心肌肥厚，但具体作用机制未明。在已筛选出包括EphA2在内的与Tiam1相互作用的蛋白目录的基础上，本项目拟利用Tiam1基因敲除及转基因小鼠，及腺病毒转染技术，在动物和细胞层面阐明Tiam1对心肌细胞肥厚和心力衰竭的调控作用及常见分子信号通路；进一步采用高效液相色谱/串联质谱寻找心肌细胞特异的Tiam1作用靶点，结合免疫共沉淀及分子克隆技术进一步探讨两者相互作用的结构域及机制；然后构建具有相互作用的蛋白的转基因或基因敲除小鼠，继续观察干预特异性靶点对心肌肥厚的治疗或逆转作用。本课题旨在阐明Tiam1在心肌肥厚中的作用及分子机制，尤其是旨在寻找到心肌细胞特异的Tiam1相互作用蛋白，为心肌肥厚及心衰的防治提供新的分子靶点。

心肌肥厚是多因素参与调节的复杂动态过程，最终会导致心力衰竭。因此，阐明心肌肥厚的调控机制对病理性心肌肥厚和心力衰竭的诊疗具有重要意义。通过本项目的深入研究，发现Tiam1在心肌肥厚及心力衰竭的疾病进展中发挥关键作用，探讨抑制Tiam1及其相互作用的靶点在预防或逆转心肌肥厚的作用，为心肌肥厚及心力衰竭的防治提供新的分子靶点及实验依据。其中重要的研究结果包括：1）发现了Tiam1在病理性心肌肥厚心脏组织中表达升高，且其基因缺失可显著改善心肌细胞肥大和心肌细胞凋亡的现象，最后我们筛选出Tiam1在心肌细胞中相互作用的靶蛋白EphA2。2）线粒体GTP酶MTG1通过TAK1-JNK/P38信号通路降低心脏中的氧化应激反应，从而改善心肌肥厚、心肌纤维化和心功能障碍。3）肌肉因子Irisin显著改善心肌细胞肥大和纤维化的的作用，并且其作用机制可能与激活MAPK信号通路有关。以上的部分研究成果已在Journal Molecular and Cellular Cardiology、Clinical Science等杂志上发表。