Pathogenic Mechanisms Underlying Diabetic Retinopathy

描述（由申请人提供）：引起糖尿病微血管病变性视网膜病变和其他血管并发症的致病过程知之甚少。一些新的证据表明炎症在起着迄今为止尚未认识到的作用。视网膜细胞和脉管系统以及其他自身细胞通过一组内在膜调节蛋白而免受自体补体蛋白的攻击。这些调节因子是衰变加速因子（CD 55）、膜辅因子蛋白（MCP或CD 46）和反应性裂解的膜抑制剂（CD 59）。我们实验室以前的研究表明，所有三种表面蛋白在视网膜及其相关血管系统中高度表达，其水平与肾小球细胞和全身血管系统相似，这些部位的内在调节活性至关重要。在最近的体外工作中，我们已经表明，1）通过与葡萄糖或核糖孵育，>90%失活，2）通过甲基乙二醛孵育迅速废除，和3）由于一个或多个活性位点赖氨酸和精氨酸残基的修饰而丧失，后者为精氨酸嘧啶。在体内的工作中，我们已经表明，从糖尿病视网膜中分离的内源性β-淀粉样蛋白是由几种糖加合物，包括arg嘧啶修饰。所提出的研究针对1）确定化学修饰在β-环糊精、MCP中的功能效应，（和CD 59），2）从结构上表征调节物上修饰的类型和位点，3）分析内源性β-CD，MCP，（和CD 59）从糖尿病患者的视网膜和其它组织中分离的蛋白质，和4）检查与视网膜病和其它糖尿病并发症相关的病理变化是否在Daf 1-/-（鼠MCP同源物）、Crry-/-（鼠MCP替代物）、CD 59 a-/-（鼠CD 59同源物）和双Daf 1-/-/-咖喱-/-或Daf 1-/- /CD 59 a-/-小鼠，用链脲佐菌素实验性地制造糖尿病。由于血管病变和视网膜病变是最终影响大多数糖尿病患者的衰弱并发症，因此充分了解其发展机制对于设计有效的治疗干预措施至关重要。

DESCRIPTION (provided by applicant): The pathogenic processes that give rise to microangiopathic retinopathy and other vascular complications in diabetes are poorly understood. Several new lines of evidence have pointed toward inflammation as playing a heretofore unrecognized role. Retinal cells and vasculature and other self cells are protected from attack by autologous complement proteins by a set of intrinsic membrane regulatory proteins. These regulators are the decay accelerating factor (DAF or CD55), the membrane cofactor protein (MCP or CD46), and the membrane inhibitor of reactive lysis (CD59). Previous studies from our lab have shown that all three surface proteins are highly expressed in the retina and its associated vasculature in levels similar to those on glomerular cells and on systemic vasculature, sites where intrinsic regulatory activity is critical. In recent in vitro work, we have shown that DAF's regulatory function is 1) >90% inactivated by incubation with glucose or ribose, 2) rapidly abrogated by methylglyoxal incubation, and 3) lost due to modification of one or more active site lysine and arginine residues, the latter to argprymidine. In in vivo work, we have shown that endogenous DAF protein isolated from diabetic retinas is modified by several sugar adducts including argpyrimidine. The proposed studies are directed toward 1) determining the functional effects of chemical modifications in DAF, MCP, (and CD59) that are induced by hyperglycemia and other metabolic abnormalities that pertain in the diabetic state, 2) structurally characterizing the types and sites of the modifications on the regulators, 3) analyzing the functions and structures of endogenous DAF, MCP, (and CD59) proteins isolated from retinas and other tissues of diabetics, and 4) examining whether the pathological changes that are associated with retinopathy and other diabetic complications develop more rapidly in Daf1-/- (murine DAF homolog), Crry-/- (murine MCP surrogate), CD59a-/- (murine CD59 homolog) and double Daf1-/- / -/- Curry-/- or Daf1-/- / CD59a-/- mice experimentally made diabetic with streptozotocln. Since vasculopathy and retinopathy are debilitating complications that eventually affect most patients with diabetes, fully understanding the mechanisms involved in their development is important in designing effective therapeutic interventions.