RENAL CRYSTAL GROWTH INHIBITOR PROTEINS

肾结石是一种常见的临床问题， 发病率和经济成本超过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。 高 肾结石的早期症状有哪些 成功预防复发的最大可能性。 这些 早期步骤包括管状流体中的石晶体的成核， 它们在肾单位内的生长和聚集， 与肾内结构相互作用。 这是一个假设 我承认这些过程主要是由特定的 结石成分晶体和大分子之间的相互作用 存在于肾小管液和尿液中。 本项目的总体目标 是为了加深我们对这些相互作用的理解 通过研究尿中主要抑制性大分子的 骨桥蛋白/尿桥蛋白（OPN）和其他大分子抑制剂， 肾结石的治疗方法有哪些？ 的 具体目标是：（1）确定OPN负责的结构基序 对草酸钙成核、生长、聚集的影响， 羟基磷灰石（晶体形成），具体而言，（a）贡献 分子的N-末端和C-末端的一半，（B）作用 推定的钙结合位点，和（c）翻译后的影响， （2）从正常人和Ca结石形成者中表征OPN 关于其对晶体形成的影响，包括，（a） 正常人尿骨桥蛋白分离及生化特性 和结石形成者，和（B）确定来自Ca-结石形成者的OPN是否 抑制结石晶体形成的程度与OPN相同， （3）研究相互作用的物理化学 OPN和其他大分子和石晶体，通过测定（a） 大分子与晶体生长之间定量关系 核，（B）它们的结构和晶体之间的关系 形成，和（c）反应条件对反应的影响。 它们与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 （4）研究调节OPN产生对骨形成的影响， CaOx结石病实验模型。 具体而言，（a）确定 药物上调OPN的产生是否改善晶体 急性或慢性给予草酸钠的动物中的沉积， (b)开发用于OPN的瞬时肾表达的体内系统， 和（c）确定OPN表达的上调是否保护和 在给予钠的动物中，下调聚集晶体沉积 草酸盐急性或慢性。

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.