Water-Soluble and Metabolically Stable Calpain Inhibitors as Cardioprotectants

我们的长期目标是发现钙蛋白酶抑制剂作为心脏病发作和中风的潜在治疗方法。心 疾病和中风是美国死亡和发病的主要原因。新药新奇 这些情况的管理需要行动机制。越来越多的证据表明 心脏缺血(心脏病发作)或脑缺血(中风)的发作会引发一连串的生化反应 激活钙蛋白酶的事件。激活的钙蛋白酶降解结构蛋白，导致细胞死亡。CalPain是 因此被认为是干预心脏病发作和中风的一个有吸引力的药理靶点。我们有 发现了钙蛋白酶的有效和选择性抑制剂。考虑到大多数已报道的钙蛋白酶抑制剂 对我们的新抑制剂感兴趣的酶没有选择性。然而，我们还没有能够 由于这些抑制剂的水溶性和代谢性较差，因此评估其心脏保护作用 药用醛基团的不稳定性。因此，我们提议合成我们的类似物 其中可氧化的乙醛基团被半缩醛掩盖或被非缩醛取代的新型缓蚀剂 可氧化性官能团，如α-酮酰胺和α-酮酰肼。这些团体将成为 并入作为可氧化醛的异构体药用替代物。我们还将把 可电离基团，以提高缓蚀剂的水溶性。这些更改将允许对 作为心脏保护剂的抑制剂。因此，要研究的中心假设是：“可溶于水和 我们新的有效和选择性的钙蛋白酶抑制剂的代谢稳定的衍生物具有心脏保护作用。 具体目标是：(1)使用基于结构的分子设计、合成和迭代方法 开发高效、选择性、水溶性、细胞通透性和代谢稳定性的酶学评价 我们新的钙蛋白酶抑制剂的类似物；(2)表征以下三种药物的心脏保护有效性 使用大鼠离体心缺血模型在特定目标#1中开发的最佳抑制剂。 实现这些目标将提供具有理想的物理化学性质的新的钙蛋白酶抑制剂，如 生物医学工具，用于研究实验动物的钙蛋白功能，并作为发现钙蛋白的药物线索 治疗心脏病和中风的新疗法。此外，拟议的研究将提供 钙蛋白酶抑制剂作为心脏保护剂的作用模式的机制洞察。

Our long-term goal is to discover calpain inhibitors as potential treatment for heart attack and stroke. Heart disease and stroke are major causes of mortality and morbidity in the United States. New drugs with novel mechanisms of action are needed for the management of these conditions. Mounting evidence suggests that an episode of cardiac ischemia (heart attack) or cerebral ischemia (stroke) initiates a chain of biochemical events that activate calpain. Activated calpain degrades structural proteins resulting in cell death. Calpain is therefore considered an attractive pharmacologic target for intervention in heart attack and stroke. We have discovered potent and selective inhibitors of calpain. Considering that most of the reported calpain inhibitors are not selective for the enzyme our new inhibitors are of interest. However, we have not been able to evaluate the cardioprotection effect of the inhibitors because of their poor water-solubility and metabolic instability of a pharmacophoric aldehyde group. We are therefore proposing to synthesize analogues of our new inhibitors in which the oxidizable aldehyde group is masked as the hemiacetal or replaced with non- oxidizable functional groups such as the alpha-ketoamide and alpha-ketohydrazide. These groups will be incorporated as isosteric pharmacophoric replacement for the oxidizable aldehyde. We will also incorporate ionizable groups to enhance water solubility of the inhibitors. The changes will allow evaluation of the inhibitors as cardioprotectants. Thus, the central hypothesis to be investigated is: "water-soluble and metabolically stable derivatives of our novel potent and selective calpain inhibitors are cardioprotective." The Specific aims are: (1) to use an iterative approach of structure-based molecular design, synthesis, and enzymological evaluation to develop potent, selective, water-soluble, cell permeable and metabolically stable analogues of our new calpain inhibitors; (2) to characterize the cardioprotection effectiveness of three of the best inhibitors that will be developed in specific aim #1 using the rat isolated heart model of global ischemia. Achievement these aims will afford new calpain inhibitors with desirable physicochemical properties as biomedical tools for studying calpain function in laboratory animals and as drug leads for the discovery of novel therapies for treating heart attack and stroke. Furthermore, the proposed studies will provide mechanistic insight into the mode of action of calpain inhibitors as cardioprotectants.