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.

美拉德或非酶糖基化反应是还原糖和蛋白质之间发生的反应。它导致蛋白质加合物和交联的形成，被认为是导致与年龄和糖尿病相关的富含胶原蛋白的组织硬化的原因。在国家衰老研究所之前的资助下，我们的实验室致力于建立体内美拉德反应的第一个荧光交联的结构、吡咯在葡萄糖引起的蛋白质老化中的作用、糖氧化在衰老中的生物学意义以及年龄相关疾病，特别是糖尿病和终末期肾病，以及糖化、糖氧化与长寿之间的关系。最后，我们的实验室从土壤生物中发现、表征并克隆了去糖化酶（阿马多里酶）。这些数据与其他实验室的数据一起表明，高级美拉德产物 (AGE) 的形成、沿葡萄糖轴的代谢途径以及与年龄相关的胶原蛋白交联之间存在密切联系。然而，虽然现在已经形成了总体情况，但尚不清楚为什么狗胶原蛋白的交联速度比人类胶原蛋白高得多，以及哪些交联对于决定老化细胞外基质的物理化学性质很重要。在具体目标 1（第 1 部分）中，我们假设在高级美拉德反应过程中必须形成非 UV 活性和/或不稳定的交联，其中除了 lys-lys 之外，还包含 lys-arg 和 arg-arg 交联。其中一些可能涉及酰胺和脒键，预计二羰基化合物在其形成过程中发挥主要作用。在具体目标 1 的第 2 部分中，我们将开始研究美拉德反应的非氧化途径（即所谓的 2,3-烯醇化途径）在交联形成中的作用，并开发其在体内发生的特异性探针。在具体目标 2 中，我们将与加州理工学院 Julie Kornfield 博士的团队合作，尝试确定在甘油醛引发的反应中对决定胶原蛋白物理化学性质最具决定性的交联。在具体目标 3 中，我们将确定导致甘油醛加速交联的交联性质和位点（具体目标 2）以及加速衰老的狗模型。我们还将研究鸟氨酸作为一种新型交联氨基酸在老化人类胶原蛋白中的潜在作用。我们预计，我们的方法将产生第一个全面的、衰老过程中胶原蛋白交联的分层图。