Adhesion molecules and liver inflammation after radiation: Role of PECAM-1.

PECAM-1(CD31)和CD99L2在炎症中的作用仍在争论中。假设在炎症条件下，PECAM-1-(可能还有CD99L2)下调和ICAM-1上调是由肿瘤坏死因子-1通过上调核因子-kB和下调JNK诱导的，从而允许炎症细胞附着到血管壁(门脉区域)并通过血管壁(门脉区域)迁移。相反，转化生长因子-β可以阻止这一过程和/或帮助修复。在野生型小鼠和PECAM-1-Ko小鼠中，将研究辐射对PECAM-1和CD99L2调节的影响。将进行肝脏切片的免疫组织学检查，细胞因子-1和靶基因(PECAM-1，ICAM-1和CD99L2)的基因在mRNA和蛋白水平的表达。此外，还将使用激光捕获显微解剖(LCM)技术测量肝小叶不同区域的mRNA(PECAM-1、ICAM-1和CD99L2)的数量。用流式细胞仪分析肝脏和炎性细胞的PECAM-1、ICAM-1和CD99L2水平。还将从RNA(聚合酶链式反应，基因阵列)和蛋白质水平(蛋白质印迹)对分离的细胞群体(通过MACS分离器)的基因表达进行研究。肿瘤坏死因子和/或转化生长因子对培养内皮细胞的影响将在迁移研究(粒细胞、巨噬细胞)中进行。这一新知识将有助于找到治疗方法，以减少辐射导致的肝脏损伤和纤维化。

The role of PECAM-1 (CD31) and CD99L2 in inflammation is still under debate. It is hypothesized that in inflammatory conditions, PECAM-1- (and possibly CD99L2)- down-regulation in parallel to ICAM-1-up-regulation is induced by TNF- through upregulation of NF-kB and downregulation of JNK allowing inflammatory cells to attach to and to transmigrate through the vessel wall (portal area). In contrast, TGF- could stop this process and/or help in repair. Effect of radiation on PECAM-1- and CD99L2- regulation will be studied after TNF- or TGF- administration in wild type mice and in PECAM-1-ko-mice. Immunohistology of liver sections, gene expression of cytokine- and target genes (PECAM-1, ICAM-1 and CD99L2) at mRNA and protein level will be performed. Furthermore, Laser capture microdissection (LCM) of liver sections will be used to measure amount of mRNA (PECAM-1, ICAM-1 and CD99L2) in the different areas of the liver lobule. Flow-cytometry analysis will be used to quantify PECAM-1, ICAM-1 and CD99L2 level on isolated liver and inflammatory cells. Gene expression will also be studied at RNA- (PCR, gene array) and protein level (Western blot) from sorted cell populations (by MACS-separator). Effect of TNF- and/or TGF- will be investigated in transmigration studies (granulocytes, macrophages) on cultured endothelial cells. The new knowledge will help to find therapeutic means to reduce radiation induced damage and fibrosis in the liver.