Glucose Modification of Proteins in Diabetic Nephropathy

描述（由申请人提供）： 摘要糖尿病是人类的主要疾病之一，现常被称为糖尿病流行病。慢性糖尿病导致严重的并发症，如糖尿病肾病，其特征是肾滤过功能下降，是终末期肾病的主要原因。一个被广泛接受的假设是，在糖尿病中，高血糖加速蛋白质的非酶化学修饰（糖化），扰乱蛋白质功能并引起糖尿病并发症。细胞外基质（ECM）的蛋白质对糖基化高度敏感，因为它们非常低的周转率，这允许修饰的积累。蛋白质糖化的传统观点是葡萄糖直接与蛋白质分子的赖氨酸残基反应，形成Amadori中间体，该中间体经历氧化转化为不同的晚期糖化终产物（AGE）。近年来，随着认识到高血糖症导致活性羰基物质（RCS）的血浆水平升高，最显著的是甲基乙二醛（MGO）和3-脱氧葡萄糖醛酮（3-DG），其来源于葡萄糖和糖化蛋白的氧化降解，出现了一种新的范式。这些化合物比葡萄糖更具反应性，并且可以诱导更快速和更广泛的致病性蛋白质损伤。这种新的模式现在得到了一些临床和流行病学研究的支持。然而，RCS产生和致病性的机制在很大程度上是未知的。我们已经取得了一些新的发现，有助于理解这种新的模式的机制，并确定了这种更新应用的方向。其中包括：a）发现由葡萄糖自氧化和Amadori中间体的氧化产生的新中间体，其质疑产生MGO和3-DG的经典机制;和B）鉴定由MGO和3-DG触发的细胞-ECM相互作用的扰动的新机制。基于这些发现，我们提出1）确定MGO和3-DG产生的新途径; 2）确定MGO和3-DG修饰蛋白质的途径;确定3）MGO和3-DG或4）MGO-和3-DG-修饰的ECM如何诱导肾小球细胞损伤。这些目标的完成将为RCS如何在高血糖环境中产生以及它们如何促进肾小球ECM的结构和功能损伤以及细胞-ECM相互作用提供新的见解，这些相互作用是糖尿病肾病发病机制的基础。 糖尿病是人类的主要疾病之一。糖尿病的高血压导致活性羰基物质（RCS）增加，这是一种称为“羰基应激”的现象。我们建议研究RCS是如何在糖尿病中产生的，以及它们是如何引起蛋白质和肾细胞损伤的。

DESCRIPTION (provided by applicant): Abstract Diabetes is one of the major human diseases, now frequently referred to as diabetes epidemic. Chronic diabetes leads to serious complications such as diabetic nephropathy, which is characterized by decline in kidney filtration function and is the leading cause of end-stage renal disease. A widely accepted hypothesis is that in diabetes hyperglycemia accelerates the non- enzymatic chemical modification of proteins (glycation), perturbing protein function and causing diabetic complications. Proteins of extracellular matrix (ECM) are highly susceptible to glycation because of their very low turnover rates, which allow for the accumulation of modifications. The traditional view of protein glycation is that glucose directly reacts with lysine residues of a protein molecule forming an Amadori intermediate that undergoes oxidative conversion to different advanced glycation end products (AGE). In recent years, a new paradigm has emerged with the understanding that hyperglycemia causes increased plasma levels of reactive carbonyl species (RCS), most prominently, methylglyoxal (MGO) and 3-deoxyglucosone (3-DG), derived from oxidative degradation of glucose and glycated proteins. These compounds are much more reactive than glucose and can induce more rapid and more widespread pathogenic protein damage. This new paradigm is now supported by a number of clinical and epidemiological studies. However, the mechanisms underlying RCS generation and pathogenicity are largely unknown. We have made several novel findings which contribute to understanding of the mechanisms of this new paradigm and which set the direction of this renewal application. These include: a) discovery of new intermediates produced from glucose autoxidation and oxidation of Amadori intermediate, which question the classical mechanisms for production of MGO and 3-DG; and b) identification of a novel mechanism of perturbation of cell-ECM interactions triggered by MGO and 3-DG. Based on these findings we propose 1) to define novel pathways of MGO and 3-DG production; 2) to define pathways of protein modification by MGO and 3-DG; to determine how 3) MGO and 3-DG or 4) MGO- and 3-DG- modified ECM can induce glomerular cell injury. The completion of these Aims will provide new insights into how RCS are generated in hyperglycemic milieu and how they may contribute to structural and functional damage of glomerular ECM and to cell-ECM interactions that underlie pathogenesis of diabetic nephropathy. Narrative Diabetes is one of the major human diseases. Hyperglycemia of diabetes causes increase in reactive carbonyl species (RCS), a phenomenon known as "carbonyl stress". We propose to investigate how RCS are generated in diabetes and how they cause protein and renal cell damage that underlie renal pathology.