PD-L1/CD80调节肺微血管内皮细胞糖代谢在脓毒症致急性肺损伤中的作用机制研究

Pulmonary microvascular endothelial cells(PMVEC) dysfunction plays an essential role in the initiation of sepsis induced acute lung injury(ALI). It is known that energy metabolism underlies the regulation of cell function, and glucose metabolism is critical to the activation and regeneration of PMVEC. Our preliminary experiments revealed that PD-L1 and CD80 expression was enhanced following ALI in a mouse model, and the inhibition of PD-L1 expression alleviated sepsis induced lung injury.In vitro, we demonstrated that inhibition of PD-L1 expression with siRNA led to the up-regulated expression of PFKFB3, a key enzyme in glycolysis. Specially, the increased expression of PFKFB3 was accompanied by the decreased endothelium permeability. Hence, we speculate that PD-L1/CD80 interaction may be involved in the inhibition of glycolysis, which further cause the cell dysfunction.This study was designed to exploring the following scientific questions: The relationship of PMVEC glucose metabolism and cell function in sepsis induced ALI; The regulatory mechanisms of PD-L1/CD80 in PMVEC glucose metabolism; The therapeutic effects of PD-L1 siRNA on glucose metabolism in sepsis induced ALI. Collectively, by focusing on the energy metabolisms, the present study will provide a new insight into the mechanisms of the development of sepsis induced ALI.

肺微血管内皮细胞（PMVEC）功能障碍是脓毒症致急性肺损伤（ALI）重要始动因素。已知能量代谢参与调节细胞功能，糖代谢途径是维持PMVEC功能的基础。我们在前期实验中发现ALI小鼠PMVEC上PD-L1和CD80表达均升高，下调PD-L1表达可减轻肺损伤的严重程度；体外实验中抑制血管内皮细胞PD-L1表达后，糖酵解关键酶PFKFB3的表达升高，而内皮细胞通透性降低。因此，我们推测PMVEC上可能存在PD-L1/CD80分子交联，通过抑制糖酵解途径引起细胞功能障碍。本课题从体外培养细胞和在体ALI小鼠两个研究模型，研究脓毒症肺损伤时内皮细胞糖代谢变化与细胞功能的关系；揭示PD-L1/CD80对PMVEC糖代谢的调控作用及其机制；并研究在体干预PD-L1表达对糖代谢的影响及其对脓毒症肺损伤的治疗作用等科学问题。本研究将从能量代谢这一新角度为深入理解脓毒症肺损伤的发病机制提供新思路。

肺微血管内皮细胞（PMVEC）功能障碍是脓毒症致急性肺损伤（ALI）重要始动因素，而糖代谢重编程与细胞功能密切相关。本研究通过细胞和在体水平实验明确了PMVEC表达PD-L1是调节内皮细胞糖代谢和屏障功能的重要靶点；利用免疫共沉淀法和特异性抗体阻断，明确了PD-L1/CD80分子交联是调节内皮细胞糖代谢的受体/配体机制；最后通过RNA-seq筛选了PD-L1调节PMVEC糖代谢的关键酶和转录因子，并给予HK-1特异性阻断，初步阐明了HK-1介导的糖酵解途径是PD-L1/CD80调控内皮细胞糖代谢和屏障功能的关键靶点。本研究从糖代谢重编程这一新角度着手，为深入理解脓毒症肺损伤的发病机制提供了新的思路。