Mechanisms of Ischemic Injury and Repair

描述（申请人提供）：拟议研究的总体目标仍然是了解缺血性肾细胞损伤和修复的机制，长期目标是建立可用于预防和治疗人类急性肾损伤（阿基）的疗法。在最后一个支持期内，我们进一步阐明了白细胞-内皮细胞相互作用的作用，确定了可能加速恢复的抗炎二十二烷类化合物，确定了睾酮对阿基病理生理学的贡献，并开发和验证了啮齿动物和人类近端小管损伤（KIM-1）的新生物标志物。我们开发了斑马鱼中毒性损伤的新模型，建立并表征了预处理的小鼠模型，并发现骨髓来源的干细胞在缺血后上皮的重建中不起直接作用。在当前提案中，第一个特定目的解决了修复期间近端上皮细胞减少的细胞来源以及近端小管细胞对组织吞噬细胞和成纤维细胞群体的潜在贡献，这些细胞参与缺血后的正常和异常修复。遗传技术将被用来标记近端小管细胞或其前体无论是在发展过程中或以后。我们将评估干/祖细胞是否参与修复，或者上皮细胞的再增殖是否是由于存活上皮细胞的去分化和增殖而发生的？使用遗传标记的方法，在第二和第三部分的具体目标，我们将确定是否巨噬细胞样细胞或成纤维细胞来自近端小管细胞或近端小管上皮祖细胞缺血后。在第二个具体目标中，我们将使用白喉毒素受体（DTR）的细胞特异性表达开发一种新的近端小管上皮细胞或巨噬细胞靶向损伤的遗传模型，并将使用这种方法建立炎症和预处理反应的决定因素，并探索巨噬细胞在缺血/再灌注损伤和修复的病理生理学中的作用。相关性（简单总结）：肾脏疾病影响很大一部分人群。了解干/祖细胞和成熟细胞在肾脏损伤后正常和异常修复中的相对作用是很重要的。此外，使用新的遗传方法来靶向肾脏损伤将有助于确定短期和长期“好”与“坏”修复的重要因素。

DESCRIPTION (provided by applicant): The overall goal of the proposed studies remains to understand the mechanisms of ischemic kidney cell injury and repair with a long range goal to establish therapies that will be useful to prevent and treat acute kidney injury (AKI) in man. Over the last support period we have further clarified the role of leukocyte- endothelial interactions, identified anti-inflammatory docosanoids which may hasten recovery, identified testosterone's contributions to the pathophysiology of AKI, and developed and validated a new biomarker of proximal tubule injury (KIM-1) in rodents and man. We have developed a new model of toxic injury in zebrafish, established and characterized mouse models of preconditioning and found that bone-marrow derived stem cells do not play a direct role in the reconstitution of the epithelium post ischemia. In the current proposal the first Specific Aim addresses the source of cells that depopulate the proximal epithelium during repair and the potential contribution of proximal tubule cells to the population of tissue phagocytes and fibroblasts that participate in normal and abnormal repair after ischemia. Genetic techniques will be used to label proximal tubule cells or their precursors either during development or later. We will evaluate whether stem/progenitor cells participate in repair or whether repopulation of the epithelium occurs as a result of dedifferentiation and proliferation of surviving epithelial cells? Using genetic labeling approaches in the second and third parts of this specific aim we will determine whether macrophage-like cells or fibroblasts derive from proximal tubule cells or proximal tubule epithelial progenitors after ischemia. In the second Specific Aim we will develop a new genetic model of targeted damage to the proximal tubule epithelial cell or macrophages using cell specific expression of the Diphtheria toxin receptor (DTR), and will use this approach to establish the determinants of the inflammatory and preconditioning responses and explore the role of macrophages in the pathophysiology of ischemia/ reperfusion injury and repair. Relevance (Lay summary): Kidney disease affects a large segment of the population. It is important to understand the relative roles of stem/progenitor cells and mature cells in the normal and abnormal repair of the kidney after it is injured. In addition the use of novel genetic approaches to target injury to the kidney will help in the determination of the factors important for "good" vs "bad" repair short term and long term.