环状RNA调控角蛋白Keratin14/17影响冠状动脉搭桥术后静脉桥血管再狭窄机制的研究

Diabetes mellitus is an independent risk factor for coronary heart disease. In diabetic patients with coronary heart disease after coronary artery bypass grafting in the saphenous vein graft restenosis compared with non diabetes, vascular bridge long-term patency rate is low, which mechanism remains to be clarified. The restenosis of vein graft is closely related to the proliferation of vascular smooth muscle cells. We found through proteomics diabetes compared with non diabetic patients with great saphenous vein vascular smooth muscle cells. The expression of Karatin14/17 protein increased significantly; and through bioinformatics screening to regulation of keratin circularRNA-circKRT, we found that their primary cultured smooth muscle cells' proliferation rate and chemotaxis were inhibited. Based on the above results, we propose that circKRT regulates the proliferation and function of vascular smooth muscle cells via Karatin14/17. This project intends to use primary cultured vascular smooth muscle cells of diabetic patients and mice inferior vena cava - carotid artery transplantation model by gene silencing and overexpression and other methods to clarify the condition of diabetes circKRT regulates karatin14/17 and excerts effects on vascular smooth muscle cell proliferation, migration, phenotype and molecular mechanism of vein graft restenosis.

糖尿病是冠心病的独立危险因素。糖尿病合并冠心病病人在冠状动脉搭桥术后其大隐静脉桥血管再狭窄发生率较非糖尿病病人高，桥血管远期通畅率低，其机理有待进一步阐明。静脉桥血管术后再狭窄与血管中膜平滑肌细胞增殖密切相关。我们通过蛋白质组学发现糖尿病较非糖尿病病人的大隐静脉桥血管中膜平滑肌细胞角蛋白Karatin14/17表达明显升高；又通过生物信息学筛查到调控角蛋白的环状RNA-circKRT，并发现其对原代培养的血管平滑肌细胞增殖速率和迁移能力有明显调控作用。据此提出circKRT通过Karatin14/17调控静脉桥血管平滑肌细胞增殖和功能的假设。本课题拟使用原代培养的糖尿病病人血管平滑肌细胞和糖尿病小鼠下腔静脉-颈动脉移植模型，通过基因沉默和过表达等方法，阐明糖尿病状态下circKRT通过调控karatin14/17影响静脉血管平滑肌细胞增殖、迁移、表型转化和桥血管再狭窄的分子机制。

糖尿病（diabetes mellitus，DM）作为冠状动脉粥样硬化性心脏病（coronary heart disease，CHD）的独立危险因素，合并DM的CHD病人在临床常见。冠脉搭桥手术术后桥血管易发生再狭窄。桥血管再狭窄除了与手术直接相关，术后血糖水平的控制也很大程度上影响桥血管的远期通畅率。临床病例随访及大量实验研究表明，在CABG术后，合并DM的病人较无DM的病人更易发生静脉桥血管病变。. （1）针对减少手术对血管的损伤，我们研发了一种用于冠状动脉搭桥手术的外科器械。本部分的研究成果已授权发明专利1项，并正在移交医疗公司对其进行成果转化。若今后成功推广并应用于外科搭桥手术，将会降低手术难度、增加搭桥吻合口的通畅程度，进而优化冠脉搭桥的实施技术与手术效果。. （2）针对术后血糖水平影响桥血管再狭窄的机制，本项目应用了蛋白组学技术，系统地研究了DM条件下血管中膜平滑肌细胞（smooth muscle cells，SMCs）相关蛋白（keratins，KRTs）的变化情况，寻找与之相关的circRNA，并使用病人自身的血管进行SMCs原代培养，进而研究相关circRNA通过调控KRT14/17影响SMCs的表型转化及增殖特性。. 我们发现，糖尿病病人大隐静脉SMCs中KRT14/17和circRNA表达上调且具有相关性， circKRTs通过调节KRTs水平促进SMCs增殖、迁移，使SMCs由收缩型向合成型转变。. 本部分的研究成果进一步为临床治疗提出新的方法及理念。项目成果不局限于为DM病人CABG术后预防桥血管再狭窄提供参考，更使我们深入理解所有接受CABG手术的病人术后桥血管病变的起因，对寻找预测桥血管再狭窄的生物标记物和干预治疗的靶点具有重要意义。