MECHANISMS OF COMPLEMENT INDUCED ENDOTHELIAL DYSFUNCTION

该建议的基础是解决补充的作用 缺血/再灌注后组织损伤机制中的激活 机关先前的证据表明，抑制C5可以阻止C5 a和C5 b的产生。 C5 b-9在体外和体内诱导炎症和组织损伤。研究 也证明了内皮细胞的氧化应激导致 通过激活甘露糖结合凝集素（MBL）激活补体 通路因此，所提出的研究是基于鉴定MBL配体 存在于内皮细胞中，这反过来可能导致新的疗法。 研究人员已经鉴定出一种由人类氧化应激诱导的配体， 与MBL结合并启动补体激活的内皮细胞 途径，从而导致细胞活化。他们还表明， MBL配体的氨基酸序列模拟乙酰葡糖胺，一种有效的 MBL结合抑制剂。肽（GLUPEP）抑制补体激活 内皮细胞的氧化应激。筛选各种已知的 与MBL具有相似结合特性的豆类凝集素导致了 凝集素的发现，结合到相同的内皮细胞凋亡，也结合到 GLUPEP，并抑制MBL沉积和补体激活， 氧化应激具体目标是：（1）确定 凝集素对缺氧/再氧内皮细胞和分离的MBL配体的作用， 2)表征氧化应激后MBL配体的表达 在HUVEC中，3）开发和表征小分子量抑制剂， MBL配体，以及4）表征凝集素在抑制 缺血/再灌注体内组织损伤反应。这些研究将 证明MBL结合的特异性抑制将减少补体 胃肠道缺血后的激活和组织损伤， 再灌注

The proposal is based on addressing the role of complement activation in the mechanism of tissue injury following ischemia/ reperfusion of organs. Previous evidence indicates that inhibition of C5 prevents C5a and C5b-9 induced inflammation and tissue injury in vitro and in vivo. Studies have also demonstrated that oxidative stress of endothelial cells leads to complement activation through activation of the mannose-binding lectin (MBL) pathway. Thus, the proposed studies are based on identifying the MBL ligand present in endothelial cells, which may in turn lead to novel therapies. Investigators have identified a ligand induced by oxidative stress of human endothelial cells that binds to MBL and initiates activation of complement pathway, thereby resulting in cellular activation. They have also shown that amino acid sequence of the MBL ligand mimics an acetylglucosamine, a potent inhibitor of MBL binding. The peptide (GLUPEP) inhibits complement activation following oxidative stress of endothelial cells. Screening of various known legume lectins that share a similar binding profile as MBL has lead to the discovery of lectins that bind to the same endothelial apoptosis, also bind to GLUPEP, and inhibit MBL deposition and complement activation following oxidative stress. The specific aims are 1) to characterize the binding of lectins to hypoxic/reoxygenated endothelial cells and the isolated MBL ligand, 2) to characterize the expression of the MBL ligand following oxidative stress in HUVEC, 3) to develop and characterize small molecular weight inhibitors of the MBL ligand, and 4) to characterize the action of lectins in inhibition of ischemia/ reperfusion in vivo tissue injury response. The studies will demonstrate that specific inhibition of MBL binding will decrease complement activation and tissue injury following gastrointestinal ischemia and reperfusion.