组蛋白甲基转移酶SMYD2对血管内皮衰老的调控作用及表观遗传机制研究

Vascular aging is one of the important factors which affects the pathological process of cardiovascular diseases. However, the epigenetic changes and regulatory mechanisms during the vascular aging are still unclear. Studies have shown that histone methyltransferase SMYD2 may be an important regulator in aging and inflammatory processes, but whether it is directly involved in endothelial cell senescence and aging-related cardiovascular diseases has not been directly proved and reported. This study will focus on the regulatory effect of SMYD2 on vascular endothelial aging and its epigenetic mechanism. Vascular aging models were constructed in vitro and in vivo respectively, and various models related to vascular aging diseases (hypertension, diabetes, etc.) were simulated. Combined with siRNA, lentivirus, the small molecule inhibitor LLY-507 and vascular endothelial cell specific SMYD2 knockout mice for SMYD2 function loss or SMYD2 overexpression revealed the role of SMYD2 in regulating vascular endothelial senescence. Furthermore, combined with RNA-seq, ChIP-seq high-throughput sequencing and other experimental methods, the new epigenetic mechanism of SMYD2 regulating aging-related phenotypes was explored from the perspectives of SMYD2 methylated histone and non-histone, which reveals potential therapeutic strategies to alleviate vascular aging, and provides an important theoretical basis for the development of drugs to treat vascular senescence related diseases and support healthy aging.

血管衰老是影响心血管疾病发生的重要因素之一，但其表观遗传学变化及调控机制目前仍不明确。研究表明，组蛋白甲基转移酶SMYD2可能是衰老及炎症反应过程的重要调控因子，但其是否直接参与血管内皮细胞衰老和衰老相关心血管疾病发生还未见文献报道。本项目将围绕SMYD2对血管内皮衰老的调控作用及其表观遗传调控机制展开研究，分别在体外体内水平构建血管衰老模型，并模拟多种血管衰老相关疾病模型（高血压、糖尿病等），结合siRNA、慢病毒、小分子抑制剂LLY-507以及血管内皮细胞特异性SMYD2敲除鼠使SMYD2功能缺失或过表达SMYD2后，揭示SMYD2调控血管内皮衰老的作用；进一步结合RNA-seq和ChIP-seq高通量测序等实验方法，从SMYD2甲基化组蛋白和非组蛋白两个角度分别探究SMYD2调控衰老相关表型基因的表观遗传新机制，为开发治疗血管衰老相关疾病及支持健康衰老的药物提供重要理论依据。

血管衰老是影响心血管疾病发生的重要因素之一，但其表观遗传学变化及调控机制目前仍不明确。组蛋白甲基转移酶SET and MYND domain-containing protein 2（Smyd2）与多种疾病（癌症、炎症性疾病等）密切相关，但其是否参与血管内皮细胞（VECs）衰老和衰老相关心血管疾病发生还未见文献报道。本项目以Angiotensin II（Ang II）诱导体内外血管衰老模型，结合siRNA、小分子抑制剂LLY-507、高/低表达慢病毒及Smyd2杂合敲除鼠（Smyd2+/-）使Smyd2功能缺失或过表达后探究Smyd2调控血管内皮衰老的作用；通过ChIP-seq高通量测序和ChIP-PCR实验揭示Smyd2调控血管内皮衰老表型的表观遗传新机制。主要结果如下：（1）Smyd2在体内外血管衰老过程中上调，敲低或抑制Smyd2缓解血管内皮细胞衰老表型，而过表达Smyd2则可直接诱导VECs衰老表型发生；（2）Smyd2低表达慢病毒或Smyd2杂合敲除鼠（Smyd2+/-）可改善Ang II持续灌注小鼠的血管衰老表型；（3）机制上，Smyd2通过H3K4me1修饰激活衰老相关基因（Cdkn1a和Cdkn2a）附近增强子元件，促进其转录和蛋白水平升高，进而促进血管衰老发生；（4）Smyd2调节血管内皮细胞衰老参与多种血管衰老相关疾病的发生发展，如高血压、糖尿病和动脉粥样硬化。本项目从Smyd2甲基化组蛋白角度探究了其调控血管内皮衰老的作用及表观遗传新机制，为开发治疗血管衰老相关疾病的药物提供重要理论依据。