ROLE OF MAC-1/ICAM-1 INTERACTIONS IN VASCULITIS

白细胞活化和白细胞-内皮细胞相互作用在血管炎病理学中的作用仍然知之甚少。该实验室最近报道了ICAM-1缺陷型MRL/MpJ-Fas/lpr小鼠表现出减少的血管炎病变形成和血管坏死。本项目将研究白细胞和动脉内皮细胞之间的ICAM-1/Mac-1相互作用介导白细胞活化、动脉内皮细胞损伤和随后在血管炎病变中观察到的动脉血管坏死的假设。该假设将使用Mac-1和ICAM-1突变小鼠进行检验，这些小鼠已经与MRL/MpJ-Fas/lpr背景（一种自发发生血管炎的品系）回交。第一个具体目的是比较Mac-1突变体和Mac-1野生型MRL/MpJ-Fas/lpr小鼠之间的血管炎病变形成。Mac-1表达的作用将在血管炎发展的各个阶段使用病理分级研究来确定。第二个具体目标是确定Mac-1/ICAM-1相互作用在体外白细胞活化和内皮细胞损伤中的作用。肠系膜动脉内皮细胞培养物将用于测量Mac-1突变型和野生型中性粒细胞与ICAM-1突变型和野生型MRL/MpJ-Fas的中性粒细胞粘附，测量Mac-1突变型和野生型中性粒细胞与ICAM-1突变型和野生型MRL/MpJ-Fas lpr内皮细胞的中性粒细胞粘附。还将使用Mac-1突变体和野生型中性粒细胞在该体外模型中测定白细胞活化和内皮细胞毒性。结合在体内和体外的方法，这个项目将显着推进我们的白细胞粘附和白细胞介导的血管坏死在血管炎的作用的理解。

The role of leukocyte activation and leukocyte-endothelial cell interactions remains poorly understood and characterized in vasculitic pathologies. This laboratory has recently reported that ICAM-1 deficient MRL/MpJ-Fas/lpr mice demonstrate reduced vasculitic lesion formation and vessel necrosis. This project will investigate the hypothesis that ICAM-1/Mac-1 interactions between leukocytes and arterial endothelial cells mediate leukocyte activation, arterial endothelial cell damage, and subsequent arterial vessel necrosis observed in vasculitic lesions. The hypothesis will be examined using both Mac-1 and ICAM-1 mutant mice that have been backcrossed onto the MRL/MpJ-Fas/lpr background, a strain that spontaneously develops vasculitis. The first specific aim is to compare vasculitic lesion formation between Mac-1 mutant and Mac-1 wild type MRL/MpJ-Fas/lpr mice. The role of Mac-1 expression will be determined during various stages of vasculitis development using pathological grading studies. The second specific aim will determine the role of Mac-1/ICAM-1 interactions in leukocyte activation and endothelial cell damage in vitro. Mesenteric arterial endothelial cell cultures will be used to measure neutrophil adhesion of Mac-1- mutant and wild type neutrophils to both ICAM-1 mutant and wild type MRL/MpJ-Fas measure neutrophil adhesion of Mac-1 mutant and wild neutrophils to both ICAM-1 mutant and wild type MRL/MpJ-Fas lpr endothelial cells. Leukocyte activation and endothelial cell cytotoxicity will also be determined using Mac-1 mutant and wild type neutrophils with this in vitro model. The combined in vivo and in vitro approach of this project will significantly advance our understanding of the role of leukocyte adhesion and leukocyte mediated vessel necrosis in vasculitis.