ADVANCED GLYCATION ENDPRODUCTS, THEIR RECEPTORS, AND VASCULAR DISEASE

工作总结晚期糖基化终末产物蛋白(AGE)在血浆和组织中随着年龄的增长而积累，在糖尿病患者中加速积累。AGEs诱导血管细胞的氧化应激，导致核因子-kB活性和单核细胞趋化蛋白-1(MCP-1)的增加，两者都与血管病变的发生有关。AGEs影响细胞基因表达的部分原因是通过激活某些细胞表面受体。其中一种被称为RAGE(AGEs受体)。它是细胞表面受体免疫球蛋白超家族的成员。我们已经从大鼠内膜血管平滑肌细胞中克隆了RAGE，并构建了表位标记的野生型和突变型受体，结果表明，野生型受体的过表达导致了部分但不是所有受试细胞中核因子-kB的表达增加。来自受体的信号导致ERK和p38MAPK活性增加，这两种活性都是Ik-Balpha降解和激活NF-kB和NF-kB依赖的基因表达所必需的。酵母中的两个杂交筛选已经确定了一些与RAGE胞浆尾巴相互作用的蛋白质。这些蛋白包括与受体介导的MAPKinase通路激活有关的适配蛋白SHC，以及先前发现的功能未知的富含亮氨酸重复序列(LRR)蛋白p37NB。P37NB的表达分布与RAGE相似。P37NB的过表达导致细胞ras活性和核因子-kB的激活增加。这些观察表明，RAGE的胞浆尾巴可以与细胞内重要的信号转导蛋白结合，这可能是AGE诱导的基因表达变化的原因。

SUMMARY OF WORK Advanced glycation endproducts of proteins (AGE) accumulate in the plasma and in tissues with advancing age and at an accelerated rate in diabetes. AGEs induce a pro-oxidant stress in vascular cells, leading to increased NF-kB activity and monocyte chemoattractant protein-1 (MCP-1), both of which have been implicated in vascular lesion development. AGEs affect cellular gene expression, in part, by engaging certain cell surface receptors. One of these is known as RAGE (Receptor for AGEs). It is a member of the immunoglobulin superfamily of cell surface receptors. We have cloned RAGE from rat intimal vascular smooth muscle cells and constructed epitope-tagged wild type and mutant receptors and shown that overexpression of wild type receptor leads to increased NF-kB expression in some but not all cells tested. Signaling from the receptor results in increased Erk and p38 MAPK activities, both of which are required for Ik-Balpha degradation and the activitation of NF-kB and NF-kB-dependent gene expression. Two hybrid screening in yeast have identified a number of proteins that interact with the cytosolic tail of RAGE. These include the adapter protein, shc, which has been implicated in receptor mediated activation of MAPKinase pathways and a previously identified leucine rich repeat (LRR) protein of unknown function known as p37NB. P37NB has a similar distribution of expression as RAGE. Overexpression of p37NB leads to increased cellular ras activity and NF-kB activation. These observations demonstrate that the cytosolic tail of RAGE can engage intracellular proteins important in signal transduction that may be responsible for AGE-induced changes in gene expression.