mir-143调控MMP2/MMP3抑制腹主动脉瘤的分子机制及靶向治疗研究

The abdominal aortic aneurysms (AAA) are caused by the imbalance of vascular structure/function, leading to dilation of the aorta. Mortality following rupture of AAA is high. MirRNAs are involoved in the key pathogenic process of vascular injury/repair. Using miRNA-sequencing of serum sample from AAA patient and health control, we found the significant decrease of mir-143 in patients with AAA and the significant correalation between decreased mir-143 levels and the incidence AAA major adversed events. Animal experiments demonstrate that mir-143 agomir treatment inhibits the development of AAA, whereas smooth muscle cells specific-mir-143 deficiency promotes AAA. Proteomics analysis reveals that mir-143 inhibits the expression of MMP2/MMP3 protein. We find that Col-IV-targeting-peptide specificly target the aneurysm. However, the underlying mechanism remains unclear. Our specific aims are: 1) to determine how the risk factors of AAA induce the methylation of transcription factor SRF, leading to downregulation of mir-143; 2) to explore the molecular mechanisms by mir-143 regulating the function of MMP2/MMP3 and inhibition of AAA; 3) to elucidate the therapeutic effects of new Col-IV-targeted nanoparticles containing mir-143 on AAA and 4) to clarify clinical value of mir-143-MMP2/MMP3 as a potential biomarker for monitoring the progression and incidence of major adverse events in patients with AAA. The present study will demonstrate the molecular mechanism of mir-143 in the resistance of aorterial dilation and provide novel therapeutic approaches and prognostic monitor for AAA.

腹主动脉瘤（AAA）是血管结构/功能稳态失衡致动脉扩张的疾病，破裂死亡率高。MicroRNA参与血管损伤/修复的病理过程。我们前期血清mirRNA测序发现AAA患者mir-143下调，与其不良事件发生相关；mir-143治疗抑制AAA发生，反之平滑肌特异性mir-143缺陷加剧其进展；蛋白组学检测发现mir-143抑制MMP2/MMP3表达；发现Col-IV多肽可靶向AAA，但mir-143下调致AAA发生机制及Col-IV是否实现AAA靶向治疗等科学问题尚不清楚。本课题探讨：1）AAA高危因素调控转录因子SRF甲基化抑制mir-143表达的机制；2）mir-143调控MMP2/MMP3抑制AAA的分子机制；3）Col-IV-阳离子材料靶向递送mir143的治疗作用；4）mir-143/MMP2/MMP3在AAA进展和预后监测的临床价值。本课题将为AAA治疗、预后监测提供新靶点和治疗途径。

主动脉瘤及夹层是心血管系统最常见的灾难性疾病，发病急、死亡率高。此类疾病以细胞外基质(ECM)失调为特征。ECM刚度的畸变可导致细胞功能的改变。然而，ECM软化调节血管平滑肌细胞(VSMC)表型转换的机制仍有待进一步研究。基础研究层面，我们在软ECM中培养VSMCs，并观察到VSMCs切换到合成表型，以及AKT信号激活介导的microRNA (miR)-143/145表达的显著降低。给药β-氨基丙腈单富马酸酯(BAPN)的小鼠的原子力显微镜和主动脉张力测试显示小鼠的主动脉早期软化，VSMCs的合成表型增加。此外，在bapn诱导软化的主动脉中，miR-143/145的表达显著降低。miR-143/145的过表达降低了bapn诱导的主动脉软化、VSMC合成表型的切换和小鼠TAD的发生率。最后，免疫沉淀RNA的高通量测序表明，TEA结构域转录因子1 (TEAD1)是miR-143/145的共同靶基因，随后荧光素酶报告试验证实了这一点。TEAD1在体外ECM软凝胶中表达上调，而TEAD1敲除后VSMCs中合成表型的开关降低。临床研究层面，建立了多中心主动脉瘤及夹层的前瞻性临床队列，收集患者完善的临床病例信息及血液标本。通过COX 回归分析、Kaplan-merior 等统计模型，分析miR-143/145水平与疾病严重程度（包括发病急慢性，撕裂血管范围等）和预后（出院后 30 天不良事件：多器官衰竭、新发夹层、夹层 破裂、全因死亡）的关联。通过本课题研究发现ECM软化是通过下调miR-143/145促进VSMC向合成表型转变的结果，是TAD的早期触发因素，并为这一致命疾病提供了治疗靶点，具有一定的临床运用前景。