Newer small molecule calpain inhibitors for TBI

相当多的实验证据现在支持一个至关重要的病理生理作用， 钙激活的蛋白质降解酶钙蛋白酶在创伤后继发性损伤过程中的作用 脑损伤（TBI）。这表明，早期使用钙蛋白酶抑制剂治疗应该能够 以减少TBI后对脑组织的继发性损伤，从而促进神经恢复和存活。 因此，已经发现了几种小分子钙蛋白酶抑制剂。其中一些已经被 在啮齿动物TBI模型中进行了测试，并在钙蛋白酶减少方面显示出一些希望， 介导的蛋白水解损伤或神经恢复的改善。 然而，没有一种可用的钙蛋白酶抑制剂在TBI模型中进行了系统的研究， 将其效果转化为临床开发是可能的。因此，本项目的总体目标 是仔细检查5种精心挑选的钙蛋白酶抑制剂的能力，包括三种新的化合物， 能够有效抑制创伤后细胞骨架蛋白水解降解、线粒体功能障碍 和神经退行性疾病，并改善神经恢复。这5种化合物将首先筛选 它们以剂量相关的方式抑制正常小鼠中钙蛋白酶活化的能力（目的1）。最有效的 化合物将被推进到测试其细胞骨架（目标2），线粒体（目标3）和 在弥漫性和局灶性TBI模型中的神经保护作用（目的4）。选择的5种化合物之一是 钙蛋白酶蛋白水解降解和自由基诱导的脂质过氧化的双重抑制剂。后者 已知继发性损伤过程通过引起神经元钙的损伤来增强钙蛋白酶激活 自我平衡机制因此，细胞内钙的增加加剧了钙蛋白酶的激活。 因此，预期钙蛋白酶和脂质过氧化双重抑制剂比钙蛋白酶和脂质过氧化双重抑制剂更有效。 任何一种化合物。除了观察早期给予a的剂量相关益处外， 钙蛋白酶抑制剂或双重钙蛋白酶抑制剂/脂质过氧化抑制剂在两种不同的TBI模型中， 将探索治疗效果窗口和最佳治疗持续时间。结果数据将 解决钙蛋白酶抑制是一种实用的神经保护治疗方法的总体假设， 定义如何最好地设计抗钙蛋白酶治疗，以便将来能够在TBI患者中进行临床试验。

Considerable experimental evidence now supports a critically important pathophysiological role for the calcium-activated, protein-degradative enzyme calpain in the secondary injury process that follows traumatic brain injury (TBI). This has suggested that that early treatment with a calpain-inhibiting drug should be able to reduce post-TBI secondary injury to brain tissue and thus facilitate neurological recovery and survival. Accordingly, several small molecule calpain inhibitors have been discovered. A few of these have been tested in rodent TBI models and have shown some promise in terms of either a decrease in calpain- mediated proteolytic damage in the injured brain tissue or an improvement in neurological recovery. However, none of the available calpain inhibitors have been systematically studies in TBI models so that translation of their effects into clinical development would be possible. Thus, the overall goal of this project is to carefully examine the ability of 5 carefully selected calpain inhibitors, including three newer compounds, to be able to effectively inhibit post-traumatic cytoskeletal proteoytic degradation, mitochondrial dysfunction and neurodegeneration and to improve neurological recovery. The 5 compounds will first be screened for their ability to inhibit calpain activation in normal mice in a dose-related fashion (Aim 1). The most effective compounds will be advanced into testing for their cytoskeletal (Aim 2), mitochondrial (Aim 3) and neuroprotective effects (Aim 4) in a diffuse and a focal TBI model. One of the 5 compounds selected is a dual inhibitor of calpain proteolytic degradation and free radical-induced lipid peroxidation. The latter secondary injury process is known to enhance calpain activation by causing impairment of neuronal calcium homeostatic mechanisms. As a result, the increase in intracellular calcium exacerbates calpain activation. Therefore, a dual inhibitor or calpain and lipid peroxidation would be expected to be more effective than a either type of compound alone. In addition to looking at the dose-related benefits of early administration of a calpain inhibitor or a dual calpain inhibitor/lipid peroxidation inhibitor in two different TBI models, the therapeutic efficacy window and the optimum duration of treatment will be explored. The resulting data will address the overall hypothesis that calpain inhibition is a practical neuroprotective therapeutic approach and define how best to design anti-calpain therapy so that future clinical trials in TBI patients are enabled.