sDR5-Fc抗体融合蛋白对猪缺血-再灌注心肌的保护作用及机制

Prolong the window period for acute myocardial infarction rescue and alleviate cardiac ischemia-reperfusion injury post revascularization is the key in clinical treatment. TRAIL （Tumor necrosis factor related apoptosis inducing ligand）is well known as its distinct ability to induce cell apoptosis and participate in immune response through binding with its main receptor, DR5 (Death Receptor 5). Our previous results demonstrated that sDR5-Fc fusion protein could obviously reduce infarction size in rat model（over 40%）and improve cardiac function. However, whether sDR5-Fc play the similar role in big animal model (pig) is not known and the underlying mechanism is still not full clear..In this study, we will pay more attention on the cardioprotective effect of sDR5-Fc in pig heart ischemia-reperfusion model, including acute injury, ventricular remodeling, and cardiac function. Furthermore, the molecular mechanism(s) will be investigated in rat and neonatal rat ventricular myocardiums (NRVMs), pig, human primary cell models, which focus on cell apoptosis pathway and immune response. The aim of this study is to reveal whether sDR5-Fc direct target myocardiums or regulate other immune cells or/and cytokines to protect myocardiums from ischemia-reperfusion injury. In summary, this study will enrich our perspective on the molecular mechanism of heart ischemia-reperfusion injury and more importantly, provide a great potential candidate for new drug development in AMI treatment.

延长急性心梗患者PCI等治疗的窗口期及降低心肌细胞再灌注损伤是目前临床心梗治疗中迫切需要解决的问题。TRAIL与其主要受体DR5（Death receptor 5）结合除诱导细胞凋亡外，也参与炎症反应过程。我们前期研究发现sDR5-Fc能够减少大鼠心肌梗死面积超过40%，具有显著的心肌细胞保护作用。研究成果已获批国家发明专利，但作用机制及大动物效果仍不十分清楚。在获得足量sDR5-Fc蛋白情况下，本项目拟：①利用大型动物（猪）心肌缺血-再灌注模型评价其对心肌急性损伤、心室重塑和心功能等的保护作用；②用大鼠及各种原代心肌细胞模型从凋亡和炎性损伤方面深入研究其心肌保护的分子机制。以期揭示sDR5-Fc的心肌保护功能是由于对心肌细胞的直接靶向或/和通过抑制炎症反应而发挥功效的。该研究结果不仅为sDR5-Fc抗体融合蛋白药物研发提供实验依据，更为心肌梗死的临床防治开辟新思路。

心肌梗死（MI）是世界范围内引起人类死亡的主要原因，至今缺乏特异性治疗药物。尽管心肌细胞死亡是公认的MI病理机制，但通过阻断凋亡进行MI治疗并不简单。心肌梗死患者死亡受体5 (Death receptor 5, DR5)及其配体TRAIL （肿瘤坏死因子TNF (tumor necrosis factor, TNF)相关凋亡诱导配体）均上调，但其在病理重塑中的作用尚不明确。我们将人可溶性DR5与人免疫球蛋白融合（sDR5-Fc）用于阻断TRAIL，通过抑制大鼠、猪和猴子的心肌细胞死亡和炎症反应而治疗MI，效果显著。机制研究发现，TRAIL通过诱导心肌细胞死亡，募集和激活的白细胞直接或间接导致心脏损伤, sDR5-Fc可逆转这一过程。转录组分析显示梗死的心脏组织中炎性细胞因子的表达增加，而sDR5-Fc阻断TRAIL显著减少了炎性细胞因子的表达。综上，我们的研究结果表明TRAIL通过靶向心肌细胞直接介导心梗后心肌损伤，并通过影响髓样细胞间接参与MI。我们在国际上首次提出阻断TRAIL可作为MI的潜在治疗策略。