New mechanistic therapies for myoglobinuric acute kidney injury

描述（由申请人提供）： 我们的武装部队经常接触危险武器、病原体、环境毒素，后来又接触对健康有长期影响的医疗对策。肾脏受其排泄的体内代谢的许多毒素的影响，包括横纹肌溶解（骨骼肌降解）、溶血、药物和外源性毒素的产物。这些化合物中的许多通过产生活性氧物质（ROS）引起急性肾损伤（阿基），活性氧物质（ROS）激活凋亡核酸内切酶。由此导致的急性肾衰竭（AKF）是一种危及生命的疾病，需要血液透析或肾移植。 这项建议是 之前的研究由退伍军人管理局的优秀评审基金资助。上一个项目的具体目标已经完成，新的目标是这些目标的逻辑延伸。先前研究的结果表明，凋亡核酸内切酶G（EndoG）在介导肌红蛋白尿阿基中的重要性要复杂得多，不仅限于DNA片段化，在某些情况下，与最初接受的完全相反。本提案基于我们最近意外的观察结果，即肌红蛋白尿性阿基是由EndoG调节的细胞凋亡脱氧核糖核酸酶I（DNase I）介导的。在本研究之前，没有描述另一种核酸内切酶对一种核酸内切酶的调节，并且EndoG被认为是DNA片段化凋亡核酸内切酶之一。与此相反，我们发现，当EndoG被较晚或较强的损伤激活时，它会使DNA酶I失活，从而防止损伤。因此，在肾脏中，EndoG充当细胞保护酶而不是细胞毒性。 我们假设肌红蛋白尿性阿基可以通过诱导EndoG介导的DNase I失活或以其他方式抑制损伤前和/或损伤后DNase I的表达或活性来预防。我们的具体目标如下。在目标1中，我们将评估基于天然DNA酶I和选择性剪接DNA酶I的治疗方法，以改善肌红蛋白尿性肾小管细胞损伤和阿基。在目标2中，我们计划确定EndoG介导的DNase I失活如何用于钝化肌纤维蛋白尿性阿基。目标3将使用我们新的高通量技术来筛选适用于治疗肌红蛋白尿阿基的新DNA酶I抑制剂的化学文库。 对退伍军人医疗保健的潜在影响。这些研究的成功完成可能会导致新的治疗工具的开发，以预防或改善肌红蛋白尿性阿基。它们中的一些将具有很强的转化价值，因为它们即使在肾损伤后施用也会起作用，而另一些则可以成为未来的治疗选择。当应用于人类时，这项研究的结果可能会挽救人类生命，改善退伍军人的健康状况，并减少退伍军人中的残疾人数。

DESCRIPTION (provided by applicant): Our armed forces are routinely exposed to hazardous weapons, pathogens, environmental toxins and, later, medical countermeasures with long-term health effects. The kidney is affected by many toxins metabolized in the body that it excretes, including products of rhabdomyolysis (skeletal muscle degradation), hemolysis, drugs, and exogenous toxins. Many of these compounds cause acute kidney injury (AKI) by producing reactive oxygen species (ROS), which activate apoptotic endonucleases. The resulting acute kidney failure (AKF) is a life-threatening condition that requires hemodialysis or kidney transplantation. This proposal is a continuation of the previous research funded by a VA Merit Review grant. The specific aims in the previous project have been accomplished and the new goals are logical extensions of these aims. The results from the previous study show that the importance of apoptotic endonuclease G (EndoG) in mediating myoglobinuric AKI is much more complex, not limited to DNA fragmentation only, and in some cases, completely opposite to what was initially accepted. The present proposal is based on our recent unexpected observations that myoglobinuric AKI is mediated by apoptotic deoxyribonuclease I (DNase I) regulated by EndoG. Prior to this study, no regulation of an endonuclease by another endonuclease has been described, and EndoG was considered one of the DNA-fragmenting apoptotic endonucleases. Contrary to this, we found that when EndoG becomes activated by later or stronger injury, it inactivates DNase I and thus protects against the injury. Therefore in the kidney, EndoG acts as cytoprotective enzyme instead of being cytotoxic. We hypothesize that myoglobinuric AKI can be prevented by inducing of EndoG-mediated inactivation of DNase I or otherwise inhibiting expression or activity of DNase I before and/or after injury. Our specific objectives are as follows. In Aim 1, we will evaluate native DNase I- and alternatively-spliced DNase I-based therapeutic approaches to ameliorate myoglobinuric tubular cell injury and AKI. In Aim 2, we plan to determine how EndoG-mediated inactivation of DNase I can be used to blunt myoglobunuric AKI. Aim 3 will be using our new high throughput technology to screen chemical library for new DNase I inhibitors applicable for the treatment of myoglobinuric AKI. Potential Impact on Veterans Health Care. Successful completion of these studies can potentially lead to the development of new therapeutic tools to prevent or ameliorate myoglobinuric AKI. Some of them will have strong translational value because they act even if administered after kidney injury, while others can become therapeutic options of the future. When applied to humans, the results of this study may allow saving human lives, improving the health of veterans, and decreasing the number of disabilities in the veteran population.