MECHANISMS OF COMPLEMENT INDUCED ENDOTHELIAL DYSFUNCTION

该建议的基础是解决补充物的作用 脑缺血再灌流后组织损伤机制中的活化 器官。先前的证据表明，抑制C5可以防止C5a和 C5b-9在体内外均可引起炎症反应和组织损伤。研究表明， 也证明了内皮细胞的氧化应激导致 甘露糖结合凝集素(MBL)激活补体 路径。因此，拟议的研究是基于确定MBL配体 存在于内皮细胞中，这反过来可能导致新的治疗方法。 研究人员确定了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，从而导致细胞激活。他们还表明， MBL配体的氨基酸序列模拟了一种有效的乙酰氨基葡萄糖 MBL结合的抑制剂。多肽(GLUPEP)抑制补体激活 跟随内皮细胞的氧化应激。筛选出各种已知的 与MBL有相似结合特征的豆科凝集素导致了 发现与相同的内皮细胞凋亡结合的凝集素，也结合 GLUPEP，并抑制MBL沉积和补体激活 氧化应激。具体目标是1)表征 凝集素对缺氧/复氧内皮细胞和分离的MBL配体， 2)研究氧化应激对MBL配体表达的影响 在HUVEC中，3)开发和表征小分子量抑制剂 MBL配体，以及4)表征凝集素在抑制肿瘤生长中的作用。 缺血/再灌注体内组织损伤反应。这些研究将 证明特异性抑制MBL结合会减少补体 胃肠道缺血再灌注后的激活和组织损伤 再灌流。

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.