COLLAGEN CROSSLINKING BY THE MAILLARD REACTIOIN IN AGING

衰老过程中美拉德反应导致的胶原蛋白交联

• 批准号: 6452358
• 负责人: VINCENT M MONNIER
• 金额: $ 3万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-30 至 2005-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6452358
• 关键词: aging; animal tissue; arginine; collagen; crosslink; dogs; glycation; glyceraldehyde; human tissue; laboratory rat; lysine; ornithine

The Maillard or non-enzymatic glycosylation reaction is the reaction which occurs between reducing sugars and proteins. It leads to the formation of protein adducts and crosslinks thought to be responsible for age- and diabetes-related stiffening of collagen-rich tissues. With previous funding from the National Institute on Aging, our laboratory has contributed toward establishing the structure of the first fluorescent cross- link of the Maillard reaction in vivo, the role of pyrroles in protein aging by glucose, the biological significance of glycoxidation in aging and age- related diseases, especially diabetes and end stage renal disease, and the relationship between glycation, glycoxidation and longevity. Finally, our laboratory has discovered, characterized and cloned deglycating enzymes (Amadoriases) from soil organisms. These data, together with those from other laboratories, now implicate a strong link between the formation of advanced of advanced Maillard products (AGEs), metabolic pathways along the glucose axis, and age- related crosslinking of collagen. However, whereas a general picture is now emerging, it is unclear why, e.g., dog collagen is becoming crosslinked at much higher rate than human collagen, and which crosslinks are important in dictating the physical-chemical properties of the aging extracellular matrix. In Specific Aim 1 (part 1), we hypothesize that non-UV active and/or labile crosslinks must be forming during the advanced Maillard reaction which comprise besides lys-lys, also lys-arg and arg-arg crosslinks. Some of these may involve amide and amidine bonds whereby dicarbonyl compounds are expected to play major roles in their formation. In part 2 of Specific Aim 1 we will initiate research into the role of the non- oxidative pathway, so called 2,3-enolization pathway of the Maillard reaction in crosslink formation and develop specific probe for its occurrence in vivo. In Specific Aim 2, we will collaborate with Dr. Julie Kornfield's group at Caltech and attempt to identify the crosslinks that are most determinant in dictating the physical-chemical properties of collagen in the reaction initiated by glyceraldehyde. In Specific Aim 3, we will identify the nature and sites of crosslinks that are responsible for the accelerated crosslinking in the glyceraldehyde (Specific Aim 2) and the dog model of accelerated aging. We will also investigate the potential role of ornithine as a novel crosslinking amino acid in aging human collagen. Our approach, we expect, will result in the first comprehensive, hierarchical map of collagen crosslinks that for, during aging.

Maillard或非酶糖基化反应是减少糖和蛋白质之间发生的反应。它导致形成蛋白质加合物和交叉链接，被认为是富含胶原蛋白的组织的年龄和糖尿病相关僵硬的原因。随着国家衰老研究所的先前资金，我们的实验室有助于建立Maillard反应在体内的首次荧光跨环节的结构，葡萄糖通过葡萄糖在蛋白质衰老中的作用，糖氧化的生物学意义，在衰老和年龄相关的疾病中，尤其是糖尿病和阶段肾脏疾病，以及GLYCCO之间的关系，以及Glycco之间的关系。最后，我们的实验室发现，特征和克隆的脱胶酶（Amadoriases）来自土壤生物体。这些数据以及其他实验室的数据现在暗示了高级Maillard产品（AGES）的高级形成，沿葡萄糖轴的代谢途径与胶原蛋白年龄相关的交联之间存在牢固的联系。但是，尽管现在正在出现一般图片，但尚不清楚为什么，例如，狗胶原蛋白的交联速度比人类胶原蛋白高得多，并且在决定衰老细胞外基质的物理化学特性方面，交联非常重要。在特定的目标1（第1部分）中，我们假设在高级Maillard反应过程中必须形成非UV活性和/或不稳定的交联，该反应还包括Lys-Lys，也包括Lys-Arg和Arg-Arg-arg交叉链接。其中一些可能涉及酰胺和胺债券，预计双骨化合物将在其形成中起主要作用。在特定目标1的第2部分中，我们将启动研究非氧化途径的作用，所谓的Maillard反应在交叉链接形成中的2,3-溶解途径，并为其在体内发生特定的探针。在特定目标2中，我们将与加州理工学院朱莉·科恩菲尔德（Julie Kornfield）的小组合作，并试图确定在甘油醛引发的反应中决定胶原蛋白的物理化学特性时最重要的交联。在特定的目标3中，我们将确定负责甘油醛中加速交联的交联的性质和位点（特定的目标2）和加速衰老的狗模型。我们还将研究鸟氨酸作为一种新型交联氨基酸在衰老的人类胶原蛋白中的潜在作用。我们期望的，我们的方法将导致第一片胶原蛋白交联的第一个全面的，分层图。