OXIDATION AND DEFORMATION IN SICKLE RBC DEHYDRATION

描述：修订后的续期申请的目的是 提高我们对相关分子机制的理解 对于镰状红细胞的异常脱水，可以说是最 这些细胞的重要细胞缺陷，并进一步澄清 铁和氧化在镰状细胞中的致病作用 疾病。该提案由两个子项目组成，分别是 相互关联的，因为它们都与阳离子问题有关 动态平衡和氧化病理生物学。关于网络游戏角色的研究 氧化在镰刀病的病理生理学中有三个特异性 目标：1)找出自氧化增加的原因 镰刀状血红蛋白，考虑到它不是来自先天的 自氧化性不稳定，而不是来自镰刀的相互作用 含过渡金属的血红蛋白、病理生理氧化剂和 膜磷脂；2)定义铁的性质 评价镰刀状红细胞的分解作用：胞浆游离 过渡金属含量及其与无膜铁的关系， 以及受影响的铁的平衡结合 胞液生理性螯合剂；金属/血红蛋白/膜的作用 膜铁沉积中的相互作用；以及铁的隔间 基因的作用；3)生化指标的检验预测 这种氧化过程的后果，包括验证 假设：不稳定的血红蛋白病膜是镰刀状的- 例如；以及使用铁络合剂去除红细胞膜铁 应该实现可预测的改进，这是一种将测试 一种潜在的治疗选择。膜的作用研究 变形诱导的红细胞阳离子渗漏有三个特点 目标：1)定义解释 由于低张变形而导致的泄漏。主导假说 有待检验的是，大分子拥挤对 对膜对变形的响应的影响；2)建立 通过测试该模型与真实镰刀的关系 预测镰刀致伤的质量特征 泄漏将取决于变形的程度；详细说明其相对 现象学；以及确定其与膜脂的关系 氢氧化物；以及3)探讨红色是否 细胞机械敏感性是由设计或偶然发生的，通过检查 已知泄漏途径的选定红细胞的变形响应 并通过使用锌处理的红细胞来检查 假设允许的机械敏感泄漏结构是 由带3蛋白聚集而成。预计 这些目标的成功实现将有助于 我们对分子基础的理解有了显著的进步 镰刀状红细胞膜的病理生物学和细胞脱水 这也导致了治疗镰状细胞疾病的新方法。

DESCRIPTION: The objective of this revised renewal application is to improve our understanding of the molecular mechanisms responsible for abnormal dehydration of sickle red cells, arguably the most important cellular defect of these cells and further clarifying the role of iron and oxidation as pathogenetic influences in sickle cell disease. The proposal comprises of two subprojects that are interrelated in that they both are relevant to problems of cation homeostasis and of oxidative pathobiology. The study on the role of oxidation in sickle disease pathophysiology has three specific aims: 1) Identify the reason for increased "autoxidation" of sickle hemoglobin, considering that it derives not from an inherent autoxidative instability but rather from interaction of sickle hemoglobin with transition metals, pathophysiologic oxidants, and membrane phospholipid; 2) Define the nature of iron decompartmentalization in sickle red cells by assessing: cytoplasmic free transition metal content and its relationship to membrane-free iron, as well as equilibrium binding of iron as influenced by cytosolic physiologic chelators; the role of metal/hemoglobin/membrane interaction in membrane iron deposition; and iron compartments as a function of genotype; 3) Test predictions about the biochemical consequences of such oxidative processes including the validating of hypotheses: that unstable hemoglobinopathy membranes are sickle- like; and that removal of red cell membrane iron using an iron chelator should effect predictable improvements, an approach that will test a potential therapeutic option. The study on the role of membrane deformation-induced cation leak from red cells has three specific aims: 1) Define mechanisms explaining the unique features of the leak resulting from hypotonic deformation. The leading hypothesis to be tested is that macromolecular crowding exerts a major influence on membrane's response to deformation; 2) Establish the relationship of this model to authentic sickling by testing the prediction that the qualitative character of the sickling-induced leak will depend on the degree of deformation; detailing its comparative phenomenology; and determining its relationship to membrane lipid hydroperoxides; and 3) Approach the question as to whether red cell mechanosensitivity occurs by design or accident by examining the deformation response of selected red cells with known leak pathway deficiencies; and by using zinc treated red cells to examine the hypothesis that a permissive mechanosensitive leak structure is formed by clustering of Band 3 protein. It is anticipated that successful accomplishment of these objectives will contribute to a significant improvement in our understanding of the molecular basis for sickle red cell membrane pathobiology and cell dehydration and could also lead to novel therapeutic approaches to sickle cell disease.