CELLULAR PATHOPHYSIOLOGY OF ACUTE RENAL FAILURE

肾小管间室损伤是缺血性脑损伤的一个显著特征。 以及相关形式的急性肾衰竭。为了功能恢复 在组织中，必须有足够数量的小管细胞存活， 恢复足够的新陈代谢，修复结构损伤， 潜在地，进行增殖以替换丢失的细胞。的 在过去十二年获拨款资助的调查 提供了一些主要的决定因素， 事件，并导致我们假设：a）屏障特性 最基本的维持细胞膜 ATP耗竭和相关急性损伤过程中细胞活力的变化 状态依赖于甘氨酸的存在; B）蛋白质 去磷酸化/再磷酸化决定了 甘氨酸亚致死结构改变的可逆性- 受保护的细胞，因此，它们的能力 功能恢复局部粘连拆卸/重新组装提供了 这种行为的一个可接近的和高度相关的实例;以及 c）甘氨酸能量功能的进行性损害- 受保护的细胞限制了它们参与依赖ATP的 修复功能和耐受甘氨酸戒断。这 损伤继发于线粒体的发育， 渗透性转变，以全或无的方式发生， 个体细胞，并且可以通过药理学和其他方法来改善 接近。我们将测试和进一步调查这些假设 四个具体目标：l）优化一种新的方法， 蛋白质酪氨酸磷酸化的测量，以评估 单个小管细胞的能量状态并应用它来澄清 这是导致我们的大脑 甘氨酸保护的缺氧的孤立小管和 在体内缺血后再灌注期间小管的行为; 2） 直接可视化线粒体通透性的发展 在肾小管细胞的过渡，定义其关系， 维持线粒体膜电位，并评估 有希望的新演习，以减轻能源不足; 3） 进一步界定突出的全球化的性质和机制， 整合素和粘着斑蛋白的改变， 在分离的小管的缺氧/复氧期间， 缺血/早期再灌注在体内和这些之间的关系 细胞能量状态的变化; 4）测试参与 可能介导观察到的ATP水平的主要因素。 依赖性，局部粘连的拆卸/重新组装 甘氨酸保护的孤立小管。

Injury to the tubule compartment is a prominent feature of ischemic and related forms of acute renal failure. For functional recovery of the tissue, sufficient numbers of tubule cells must survive, resume adequate metabolism, repair structural damage, and, potentially, undergo proliferation to replace lost cells. The investigations supported by this grant during the past 12 years have provided insight into some of the major determinants of these events and have led us to hypothesize that: a) The barrier property of the plasma membrane that most fundamentally permits maintenance of cell viability during ATP depletion and related acute injury states is dependent on the presence of glycine; b) Protein dephosphorylation/rephosphorylation determines the extent and reversibility of sublethal structural alterations in glycine- protected cells and, as a consequence, their capacity for functional recovery. Focal adhesion disassembly/reassembly provides an approachable and highly relevant instance of this behavior; and c) Progressive impairment of energetic function in glycine- protected cells limits their ability to engage in ATP-dependent repair functions and to tolerate glycine withdrawal. This impairment is secondary to development of the mitochondrial permeability transition, occurs in an all or none fashion in individual cells, and can he improved by pharmacological and other approaches. We will test and further investigate these hypotheses in four Specific Aims: l) Optimize a novel approach using measurements of protein tyrosine phosphorylation to assess the energetic state of individual tubule cells and apply it to clarify the basis for the progressive energetic defect that develops in populations of glycine-protected, hypoxic, isolated tubules and the behavior of tubules during reperfusion after ischemia in vivo; 2) Directly visualize development of the mitochondrial permeability transition in the tubule cells, define its relationship to maintenance of the mitochondrial membrane potential, and assess promising new maneuvers to alleviate the energetic deficit; 3) Further define the nature and mechanisms of the prominent alterations of integrins and focal adhesion proteins that occur during hypoxia/reoxygenation of the isolated tubules and ischemia/early reperfusion in vivo and the relationships of these changes to the cellular energetic state; 4) Test the involvement of major factors potentially mediating the observed ATP level. dependent, disassembly/reassembly of focal adhesions in the glycine-protected, isolated tubules.