Probing an Unexplored Intracellular Pathway in Diabetes Pathogenesis

摘要 糖尿病肾病和其他糖尿病并发症给患者和医疗保健带来巨大负担 系统，因此必须确定可操作的病因因素，并开发有效，低成本的治疗方法 干预措施。蛋白质非酶糖基化和晚期糖基化终产物（AGEs）的形成， 与发病机制密切相关。AGE形成的驱动因子是3-脱氧葡萄糖酮（3DG），一种高反应性的 二羰基物质，也会通过破坏酶和DNA并使细胞发炎而引起急性细胞毒性。 脉管系统因此，准确测量3DG水平并了解其病因的能力是至关重要的 阐明糖尿病的发病机制，限制其致病作用，提高糖尿病的临床治疗水平， 并发症内源性3DG被认为是从糖化的糖蛋白的缓慢分解中非酶促产生的。 体内的蛋白质或从摄入的热加工食品中吸收。我们开发了新的方法来研究 果糖胺-3-激酶（FN3K）的酶活性，这种酶被认为可以修复糖化蛋白质并防止 AGE，但FN3K活性的终产物是3DG。我们发现肾脏中的3DG水平高于 此前预计。我们的核心假设是，FN3K介导的细胞内3DG形成是一个关键的致病因素， 糖尿病并发症的司机具体目标1：我们将测量组织中产生的3DG， 在2型糖尿病的KK. Cg-Ay/J鼠模型中的发病机制。具体目标2：高糖化的影响 将在对糖尿病并发症敏感的组织中，包括在肾脏，心脏， 和糖尿病小鼠的肝脏。具体目标3：我们将定义的药效学特性和模式 对葡甲胺采取行动，葡甲胺是一种已经被证明安全的药物，我们发现它有未被认识的药效， 在糖尿病小鼠中提供肾保护并防止甘油三酯积累。具体目标4：a 我们发现的一系列FN3K拮抗剂将被表征以确定临床前药物开发 候选人该提案提供了几个在糖尿病领域具有重要意义和影响的主要创新要素 翻译研究目标1将提供新的数据开发的方法，我们完善，以衡量FN3K 更准确地开展活动和形成3DG，解决知识方面的关键差距。目标2将探讨 细胞内3DG升高和食用富含果糖胺的"西方"饮食之间的关系 关于FN3K药物安全性对于任何新的糖尿病药物都是至关重要的。Aim 3的数据将加速 开发葡甲胺作为一种创新的治疗方式-一种被证明对慢性疾病非常安全的化合物 给药-以改善糖尿病肾病、脂肪肝和潜在的其它糖尿病并发症。目的 4提供了提供一流的酶抑制剂作为潜在药物先导候选物的机会。总之，这 研究计划将阐明糖尿病发病机制中未探索的细胞内途径， 为更广泛地研究3DG在糖尿病肾病和其他糖尿病中的作用提供了前所未有的工具 并发症

ABSTRACT Diabetic nephropathy and other diabetes complications impose enormous burdens on patients and healthcare systems, making it imperative to define actionable etiologic factors and develop effective, low-cost therapeutic interventions. Nonenzymatic protein glycation and the formation of advanced glycation end products (AGEs) are strongly implicated in pathogenesis. The driver of AGE formation is 3-deoxyglucosone (3DG), a highly reactive dicarbonyl species that also causes acute cellular toxicities by damaging enzymes and DNA and inflaming the vasculature. Accordingly, the ability to accurately measure 3DG levels and understand its etiology are paramount to elucidating pathogenesis, limiting its pathogenic effects, and improving clinical management of diabetic complications. Endogenous 3DG was deemed to arise nonenzymatically from the slow disintegration of glycated proteins in the body or absorbed from ingested heat-processed foods. We developed new methods to study the enzymatic activity of fructosamine-3-kinase (FN3K), an enzyme thought to repair glycated proteins and prevent AGE, but an end-product of FN3K activity is 3DG. We discovered that 3DG levels in kidney are higher than previously anticipated. Our core hypothesis is that FN3K-mediated 3DG formation in cells is a key pathogenic driver in diabetic complications. Specific Aim 1: we will measure 3DG arising in tissues in relationship to pathogenesis in the KK.Cg-Ay/J murine model of type-2 diabetes. Specific Aim 2: the impact of a high glycation diet on 3DG levels will be measured in tissues sensitive to diabetic complications, including in the kidney, heart, and liver of the diabetic mice. Specific Aim 3: We will define the pharmacodynamic properties and modes of action for meglumine, an agent, already proven safe, that we discovered has unrecognized medicinal effects, having provided nephroprotection and prevented triglyceride accumulation in diabetic mice. Specific Aim 4: a series of FN3K antagonists that we discovered will be characterized to identify a preclinical drug development candidate. This proposal offers several major innovative elements of high significance and impact in diabetes translational research. Aim 1 will provide new data developed with methodology we refined to measure FN3K activity and 3DG formation more accurately, addressing key gaps in knowledge. Aim 2 will explore the linkage between intracellular 3DG elevation and the consumption of ‘Western’ diets rich in fructosamines—the substrate for FN3K. Drug safety is paramount for any new diabetes drug. The data from Aim 3 will accelerate the development of meglumine as an innovative treatment modality—a compound proven extremely safe for chronic administration—to ameliorate diabetic nephropathy, fatty liver, and potentially other diabetic complications. Aim 4 offers opportunity to deliver first-in-class enzyme inhibitors as potential drug lead candidates. In summary, this research program will illuminate an unexplored intracellular pathway in diabetes pathogenesis and deliver unprecedented tools for broader research into the role of 3DG in diabetic nephropathy and other diabetes complications.