CaP, crystal responsible for idiopathic nephrolithasis

CaP，导致特发性肾结石的晶体

• 批准号: 7416628
• 负责人: SAEED R. KHAN
• 金额: $ 30万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7416628
• 关键词: Adherence; Adhesions; Age; Apatites; CTF1 gene; Calcium; Calcium Oxalate; Calculi; Cell Communication; Cell Line; Cell membrane; Cell surface; Cells; Cessation of life; Chemotactic Factors; Chronic; Condition; Consensus; Crystal Formation; Crystallization; Deposition; Disease; Distal; Duct (organ) structure; Endocytosis; England; Environment; Epithelial; Epithelial Cells; Exposure to; Fibroblasts; Free Radicals; Giant Cells; Henle' s loop; Human; Hydroxyapatites; In Vitro; Individual; Inflammation; Inflammatory; Inflammatory Response; Investigation; Kidney; Kidney Calculi; Kidney Papilla; Kidney Part; Lead; Lipid Peroxidation; Location; MDCK cell; Membrane; Modification; Molecular; Monocyte Chemoattractant Protein-1; Nephrolithiasis; Nephrons; Numbers; Pathogenesis; Patients; Phase; Play; Population; Prevalence; Process; Production; Reaction; Recurrence; Renal tubule structure; Research; Research Personnel; Resistance; Role; Saudi Arabia; Serum Proteins; Side; Solid; Solutions; Surface; System; Testing; Tubular formation; United States National Institutes of Health; Urinary Calculi; Urine; base; bikunin; brushite; calcium phosphate; cell injury; cost; experience; interstitial; kidney cell; macromolecule; macrophage; men; monocyte; osteopontin; prevent; programs; renal epithelium; response; surface coating; symposium; theories; tissue culture; urinary; urolithiasis

DESCRIPTION (provided by applicant): Nephrolithksis is a result of crystal formation and retention within the kidneys. Several studies have shown that conditions are favorable for the formation of calcium phosphate (CaP) in early segments of the nephron namely proximal tubules and the loops of Henle. It is proposed that CaP formed in early segments promote nucleation of calcium oxalate (CaOx) in the collecting ducts. Renal epithelial cells exposed to non-physiologically high levels of oxakte and/or CaOx crystals experience both structural and functional changes, which may eventually lead to cell injury and death. These changes also promote crystal attachment to cell surfaces and retention within the renal tubules. As a protective response, CaOx crystals are often endocytosed at the luminal side and exocytosed into die interstitium where they are processed by the inflammatory defense indicated by the presence of monocytes, macrophages and giant cells. Interestingly CaP crystals seen in the renal interstitium do not induce an inflammatory response. Even though CaP is considered the primary crystal and crystal induced changes in epithelial cells are essential for crystal retention, studies have yet to investigate crystal cell interactions between CaP and renal epithelial cells. CaP has also been shown to dissolve in the acidic environment of the collecting ducts. It is our hypothesis that crystals formed in the urine contain a surface coat, which inhibits crystal dissolution. We also hypothesize that similar to CaOx crystals, an exposure to crystals of CaP also challenges the cells and leads to alterations in renal epithelial cells, which promote crystal retention. We propose to test our hypotheses by exposing proximal tubular origin HK-2 and collecting duct origin MDCK cells to CaP crystals in culture. Two forms of CaP, inorganic apatite and brushite as well as apatite and brushite coated with urinary macromolecules will be used. In addition we propose to investigate the interaction between CaP crystals and renal interstitial fibroblasts to find out why renal interstitial CaP deposits do not cause inflammation. We have the following Specific Aims. 1. To confirm that CaP crystals coated with urinary macromolecules, are resistant to dissolution and good nucleators of CaOx in acidic environment of collecting ducts. 2. To probe that exposure to CaP crystals is associated with renal epithelial cellular injury and that exposure of renal epithelial cells to CaP crystals causes free radical production and lipid peroxidation. 3. To show that production by renal epithelial cells of crystallization modulators such as osteopontin (OPN) and bikunin and a-1 microglobulin is upregulated on exposure to CaP crystals. 4. To demonstrate that CaOx crystal adherence to renal epithelial cells is increased by their previous exposure to CaP crystals and nucleation of CaOx crystals is promoted by surface membranes of the cells pre-exposed to CaP crystals. 5. To determine the molecular mechanism for the inability of renal interstitial CaP crystals to provoke an inflammatory reaction.

描述(申请人提供)：肾结石是肾脏内晶体形成和滞留的结果。一些研究表明，条件有利于在肾单位的早期段，即近端小管和Henle环形成磷酸钙(CaP)。初步认为，在收集管中，早期形成的帽促进了草酸钙(CaOx)的成核。肾上皮细胞暴露在非生理性高水平的oxakte和/或CaOx晶体中会发生结构和功能的改变，最终可能导致细胞损伤和死亡。这些变化也促进了晶体附着在细胞表面和滞留在肾小管内。作为一种保护性反应，CaOx晶体通常在管腔一侧被内吞，然后排出到间质中，在那里它们被单核细胞、巨噬细胞和巨细胞所指示的炎症防御所处理。有趣的是，肾间质中可见的帽状晶体不会引起炎症反应。尽管CaP被认为是原发晶体，而且晶体引起的上皮细胞的变化对晶体的保留是必不可少的，但尚未有研究探讨CaP与肾上皮细胞之间的晶体细胞相互作用。CAP还被证明在收集管道的酸性环境中溶解。我们的假设是，在尿液中形成的晶体含有一层表面涂层，这抑制了晶体的溶解。我们还假设，与CaOx晶体类似，接触CaOx晶体也会挑战细胞，导致肾上皮细胞改变，从而促进晶体保留。我们建议通过暴露近端小管起源HK-2和收集导管起源的MDCK细胞在培养中覆盖晶体来检验我们的假设。将使用两种形式的帽子，无机磷灰石和刷石以及包裹有尿大分子的磷灰石和刷石。此外，我们建议研究肾间质成纤维细胞和肾间质成纤维细胞之间的相互作用，以找出为什么肾间质帽沉积不会引起炎症。我们有以下具体目标。1.证实包覆有尿液大分子的帽状晶体，在收集管的酸性环境中具有良好的抗氧化性和成核性。2.探讨CAP晶体暴露与肾上皮细胞损伤的关系以及肾上皮细胞暴露于CAP晶体可引起自由基产生和脂质过氧化。3.提示肾上皮细胞在冠状晶体作用下，骨桥蛋白(OPN)、比库宁(Bikunin)和α-1微球蛋白等结晶调节剂的产生增加。4.证明CaOx晶体与肾上皮细胞的粘附力因CaOx晶体预先暴露于CaOx晶体而增加，CaOx晶体的成核受到预先暴露于CaOx晶体的细胞表面膜的促进。5.探讨肾间质帽晶体不能引起炎症反应的分子机制。