内皮细胞中的Calpain1/2在异种心脏移植的延迟性排斥反应中的作用研究

内皮细胞活化是延迟性排斥反应发生的中心环节，抑制内皮细胞激活有助于降低延迟性排斥反应。研究提示：抑制Calpain1/2活性后可以减少内皮细胞内ROS产生，通过MAPK/ERK信号，减少淋巴细胞与内皮相互作用，提高血管内皮功能。我们前期发现内皮细胞特异性敲除Calpain4后可以有效抑制内皮细胞中Calpain1/2表达，将该转基因小鼠的心脏移植到大鼠体内后，移植心脏存活时间明显延长，同时炎症因子表达明显降低。由此推断：抑制内皮细胞中的Calpain1/2后，内皮细胞功能改善，心脏移植物存活时间延长。但是具体机制不明确。本项目将以Calpain4敲除转基因小鼠心脏作为供心，构建异种心脏移植模型。采用腺病毒以及Crispr/Cas9 knockout质粒转染等方法，证实Calpain1/2通过MAPK/ERK信号通路调控内皮细胞在移植排斥中的作用，为异种移植的延迟性排斥反应提供新的理论。

Activation of endothelial cells is the key link in delayed rejection reaction. Inhibition of activation in endothelial cells prevents delayed rejection. Previous researches suggest that disruption of calpain1/2 reduce generation of ROS in endothelial cells. Calpain1 and calpain2 regulate the interactions of lymphocytes and endothelial cells by MAPK/ERK signal. We previously showed that deletion of endotheliocyte calpain4 effectively inhibited the protein expression of calpain1 and calpain2 in endothelial cells. When hearts from the transgenic mice were transplantated into rat, mean survival time of grafts were significantly prolonged. At the same time, the concertration of inflammatory factors were decreased in grafts from calpain4 knockout mice. It highlights inhibition of calpain1/2 in endothelial cells improves the function of graft and reduces inflammation , thereby prolong the survival time of graft. But the main mechanism is not clear. The objective is to clarify the role of endotheliocyte calpain1/2 involved in xenograft rejection through MAPK / ERK signaling. The main methods include adenovirus and crispr/cas9 knockout plasmid transfection and cardiac xenotransplantation model with hearts from calpain4 knockout mice. We will refine the new theory in delayed xenograft rejection.