凝血蛋白酶aPC通过调控冷休克蛋白YB-1对糖尿病心肌病的保护作用及其机制的研究

Diabetic cardiomyopathy (DCM) was first recognized approximately four decades ago. To date, several pathophysiological mechanisms thought to be responsible for this new entity have also been recognized. Traditional treatment of heart failure is beneficial in diabetic cardiomyopathy, but specific strategies for prevention or treatment of cardiac dysfunction in diabetic patients has not been clarified yet. The cold shock protein YB-1 is a highly conserved protein involved in the regulation of inflammatory processes, including sterile inflammation in cardiac disease. A recent study shows that coagulation protease aPC can ameliorate renal ischemic injury by inhibiting the degradation of YB-1 protein via proteasome, and this process is regulated by deubiquitinase OTUB1. Our preliminary study reveals that YB-1 protein level is down regulated in murine diabetic heart tissue, and aPC can reverse the high glucose induced YB-1 protein decrease in cardiomyocyte in vitro. Thus, we hypothesize that aPC can maintain YB-1 expression via specific mechanism(s) and result in protection in DCM. To further verify the relationship between aPC, cellular YB-1 expression and DCM outcomes, CRISPR-Cas9 technology will be applied to generate YB-1 knock out cardiomyocytes, with which we will find out the links in between. Subsequently the detailed mechanism(s) by which aPC regulates the expression of YB-1 will be investigated at transcriptional, translational and post-translational levels and whether the aPC´s anticoagulant property play a role will also be studied concomitantly. In conclusion the current study will provide new thought and therapeutic strategy in the field of DCM.

糖尿病心肌病（DCM）被发现约四十多年，一些参与发病的病理生理机制逐步被发现。虽然传统心衰疗法对于DCM同样是有益的，但是针对DCM特异性的防治措施仍缺失。冷休克蛋白YB-1是一种高度保守的蛋白，它参与调节炎症过程，包括心脏的无菌性炎症。最近研究表明凝血蛋白酶aPC可以通过调节去泛素化酶OTUB1从而抑制YB-1经由蛋白酶体的降解来改善肾缺血再灌注损伤。我们的初步结果显示YB-1蛋白在DCM小鼠心脏组织中也是减少的，并且aPC能逆转高糖诱导的体外心肌细胞YB-1的下调。因此我们推测aPC可以通过特定的机制维持YB-1的表达并对DCM起保护作用。我们将首先运用CRISPR-Cas9技术建立YB-1基因敲除的心肌细胞来进一步明确aPC、YB-1和DCM表型之间的关系，接下来会在转录、翻译和翻译后水平研究aPC及其抗凝血功能是如何调控YB-1的表达，我们的研究将为DCM领域提供新的防治策略。

流行病学研究表明, 70%以上的糖尿病病人死于心血管疾病，糖尿病心肌病(DCM)是糖尿病患者主要心脏并发症之一, 其发病率高, 危害极大。然而, DCM的发生机制尚不明确，对DCM的防治仍缺乏有效手段。因此，阐明DCM的病理生理机制具有非常重要的临床意义。凝血蛋白酶活化蛋白C (aPC) 被发现对糖尿病肾病，缺血性心肌病，脑卒中等多种急慢性疾病具有保护作用，然而aPC对DCM是否具有保护作用仍不明了。本研究采用链脲霉素 (STZ) 诱导的小鼠1型糖尿病模型首次证实了aPC在DCM中的保护作用, 其保护作用是通过同心肌细胞膜上PAR1及EPCR受体结合，维持细胞内去泛素化酶OTUB1的表达及促进其同冷休克蛋白YB1的相互作用，从而降低YB1的泛素化水平及降解来实现的。而YB1对心脏功能的影响可能是通过调节核转录因子MEF2B来实现的。本研究为治疗糖尿病心肌病提供新的思路和理论依据。