In vitro and in vivo models of acute inflammatory response of endothelial cells induced by activation of the complement alternative pathway
【摘要】：Endothelial cells(EC) are important multifunctional cells. EC activation, dysfunction, and injuryplay an important role in a wide variety of diseases. As an important component of innateand adaptive immunity, the complement system plays a critical role in the immune responses.But excessive or dysregulated complement activation may contribute to inflammationand tissue injury under pathological conditions. The biologically active products ofthe complement system may induce important functional responses of EC. The presentstudy focused on inflammatory response of EC induced by activation of the alternativecomplement pathway in vitro and in vivo. Cobra venom factor(CVF), a protein isolatedfrom cobra venom, which is a structural and functional homologue of complement C3, wasemployed to specifically activate the alternative pathway of complement. After exposure toCVF-activated complement, P-selectin was rapidly released by EC. Then expression of Eselectin,ICAM-1, MCP-1, IL-8, tPA, and PAI-1 was up-regulated. JAK2, p38 MAPK, and NF-κB signaling pathways were activated. Activation of the signaling pathways was inhibitedby AG490, SB203580, and PDTC, respectively. But only AG490 effectively inhibited the expressionof ICAM-1. Increased LDH leakage, activated caspase-8, decreased NO releaseand cell viability were detected. After CVF was injected into rats via the tail vein, the concentrationsof P-selectin, PF-4, and β-TG were significantly up-regulated in blood, and thelevels of TNF-α, ICAM-1,and MPO in lung were significantly increased. Bleeding time ofmice was significantly shortened after CVF injection. These results indicated that acute inflammatoryresponse of EC was induced by CVF-activated complement in the models mentionedabove. In vitro and in vivo models of inflammatory response of endothelial cells inducedby CVF-activated complement may provide effective strategy and potential varioustargets for screening candidates that can inhibit inflammation. This study also provides abetter understanding of the role that CVF plays in cobra envenomation.