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。心脏 疾病和中风是美国死亡和发病的主要原因。新的药物 需要有行动机制来管理这些条件。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。钙蛋白酶是 因此被认为是心脏病发作和中风干预的有吸引力的药理学靶点。我们有 发现了有效的选择性钙蛋白酶抑制剂考虑到大多数报道的钙蛋白酶抑制剂 对我们感兴趣的酶没有选择性。然而，我们未能 评价抑制剂的心脏保护作用，因为它们的水溶性和代谢性较差， 药效学醛基的不稳定性。因此，我们建议合成我们的类似物。 新的抑制剂，其中可氧化的醛基被半缩醛掩蔽或被非- 可氧化的官能团如α-酮酰胺和α-酮酰肼。这些团体将 作为可氧化醛的电子等排药效团替代物掺入。我们还将把 可电离基团以增强抑制剂的水溶性。这些变化将允许评估 抑制剂作为心脏保护剂。因此，要研究的中心假设是：“水溶性和 本发明的新型有效和选择性钙蛋白酶抑制剂的代谢稳定衍生物具有心脏保护作用。“那 具体目标是：（1）使用基于结构的分子设计，合成， 酶学评价，以开发强效、选择性、水溶性、细胞渗透性和代谢稳定性 我们的新钙蛋白酶抑制剂的类似物;（2）表征三种钙蛋白酶抑制剂的心脏保护效果。 最好的抑制剂，将在具体目标#1使用大鼠离体心脏模型的全球缺血开发。 这些目标的实现将提供具有所需物理化学性质的新型钙蛋白酶抑制剂， 生物医学工具，用于研究钙蛋白酶在实验室动物中的功能， 治疗心脏病和中风的新疗法。此外，拟议的研究将提供 对钙蛋白酶抑制剂作为心脏保护剂的作用模式的机械见解。

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.