RENAL CRYSTAL GROWTH INHIBITOR PROTEINS

肾结石是一种常见的临床问题，对 发病率和经济损失超过20亿美元/年。 尽管治疗取得了进展，但结石的复发率仍然很高。 很高。阻断肾结石形成的早期步骤 成功预防复发的最大可能性。这些 早期步骤包括结石晶体在管状液体中的成核和 它们在肾单位内的生长和聚集到可以 与一些肾内结构相互作用。这就是我们的假设 授权这些流程主要由特定的 石材成分晶体与大分子的相互作用 存在于肾小管液和尿液中。这个项目的总体目标是 是为了增进我们对其中一种相互作用的作用的理解 通过对主要尿液抑制大分子的研究 骨桥蛋白/尿桥蛋白(OPN)和其他大分子骨桥蛋白抑制物 晶体的形成一般在肾结石的发展过程中起作用。这个 具体目标是：(1)确定OPN负责的结构主题 对草酸钙的成核、生长和聚集的影响和 羟基磷灰石(晶体形成)，具体而言，(A)贡献 在分子的N端和C端的一半中，(B)作用 和(C)翻译后的影响 修饰；(2)正常人和钙结石患者OPN的特征 关于其对晶体形成的影响，包括：(A) 正常人尿液中骨桥蛋白的分离及生化特性 和成石者，以及(B)确定来自钙成石者的OPN 抑制结石晶体形成的程度与正常情况下的OPN相同 个体；(3)研究相互作用的物理化学 OPN和其他大分子和石头晶体，通过测定(A) 大分子与晶体生长的定量关系 原子核，(B)它们的结构和晶体之间的关系 以及(C)反应条件对反应的影响。 它们与正在生长的晶核之间的相互作用，并通过检查 (D)固定化大分子与晶体的相互作用 形成；(4)研究调节OPN生产对An的影响 实验性CaOx结石模型的建立。具体而言，(A)确定 药物上调骨桥蛋白的产生是否能改善晶体 急性或长期给予草酸钠的动物体内的沉积， (B)开发OPN瞬时肾脏表达的体内系统， 以及(C)确定上调OPN表达是否保护和 给予钠可下调动物体内Aggrevates晶体沉积 草酸或急性或慢性草酸。

Kidney stones are a common clinical problem responsible for significant morbidity and economic costs in excess of 2 billion dollars/year. Despite progress in treatment, the recurrence rate of stones remains high. Interrupting early steps in the formation of kidney stones have the greatest likelihood of successfully preventing recurrence. These early steps include nucleation of stone crystals in tubular fluid and their growth and aggregation within the nephron to a size that can interact with some intrarenal structure. It is the hypothesis of this grant that these processes are primarily determined by specific interactions between stone constituent crystals and macromolecules present in tubular fluid and urine. The overall goal of this project is to advance our understanding of the role of one of these interactions by studying those of the principal urinary inhibitory macromolecule osteopontin/uropontin (OPN) and other macromolecular inhibitors of crystal formation in general in the development of kidney stones. The specific aims are: (1) Determining structural motifs of OPN responsible for effects on nucleation, growth, aggregation of calcium oxalate and hydroxyapatite (crystal formation), specifically, (a) the contributions of the N-terminal and C-terminal halves of the molecule, (b) the roles of putative Ca-binding sites, and (c) the effects of post-translational modifications; (2) Characterizing OPN from normals and Ca stone-formers with respect to its effects on crystal formation, including, (a) isolation and biochemical characterization of OPN from urine of normals and stone-formers, and (b) determining whether OPN from Ca-stone formers inhibits stone crystal formation to the same degree as OPN from normal individuals; (3) Investigating the physical chemistry of the interaction of OPN and other macromolecules and stone crystals, by determining (a) the quantitative relationship between macromolecules and growing crystal nuclei, (b) the relationship between their structure and crystal formation, and (c) the effects of the reactions conditions on the interaction between them and growing crystal nuclei, and by examining (d) the interactions between immobilized macromolecules and crystal formation; (4) Examining the effects of regulating OPN production on an experimental model of CaOx stone disease. Specifically, (a) determining whether pharmacolgic upregulation of OPN production ameliorates crystal deposition in animals given Na oxalate either acutely or chronically, (b) developing an in vivo system for transient renal expression of OPN, and (c) determining whether upregulation of OPN expression protects and down-regulation aggrevates crystal deposition in animals given Na oxalate either acutely or chronically.