PATHOGENESIS OF FAMILIAL JUVENILE NEPHRONOPHTHISIS

家族性青少年肾病的发病机制

• 批准号: 6517623
• 负责人: Steven K. Hanks
• 金额: $ 23.27万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-05-01 至 2004-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6517623
• 关键词: cell adhesion; congenital kidney disorder; gene expression; genetic disorder; histogenesis; immunocytochemistry; in situ hybridization; laboratory mouse; molecular pathology; pathologic process; phosphorylation; protein biosynthesis; protein protein interaction; protein tyrosine kinase; proteins; renal tubule; tight junctions

The long-term objective of this proposal is to understand the nature of the cellular defects underlying the pathogenesis of familial juvenile nephronophthisis (NPH) -- a common genetic cause of kidney failure in children. Although clinical and histological observations indicate NPH results from a loss of normal excretory tubule function, the pathogenesis of the disease remains obscure. Recently a human gene mutated in the majority of NPH cases was isolated and the sequence of its encoded protein ("nephrocystin") was determined. A clue to the biochemical function of nephrocystin is the presence of a "Src homology 3" (SH3) domain known for mediating specific protein-protein interactions. New insight into the pathogenesis of NPH will now come from further study of nephrocystin. In preliminary studies, cDNAs encoding mouse nephrocystin have been isolated and the transcripts have been detected during post-implantation mouse embryogenesis and in a variety of adult tissues including the kidney. New information concerning the biochemical function of nephrocystin was obtained by identifying a tyrosine kinase substrate, pl30Cas, as a protein bound by the nephrocystin SH3 domain and by showing that nephrocystin localizes to lateral membranes of polarized epithelial cells. These observations led to our general hypothesis that nephrocystin functions in the morphogenesis and/or maintenance of the kidney tubular epithelium, requiring specific interactions with pl30Cas and other proteins involved in cell adhesive interactions. To test and expand the hypothesis, specific aims are proposed to: 1) determine the spatial pattern of expression of nephrocystin in developing mouse embryos and in the adult kidney, 2) further identify and characterize relevant nephrocystin-interacting proteins, and 3) determine the effects of nephrocystin on adhesion regulated p130Cas tyrosine phosphorylation and epithelial cell tight junction formation and tubulogenesis.

这项建议的长期目标是了解家族性青少年肾单位病(NPH)的细胞缺陷的本质，NPH是儿童肾功能衰竭的一种常见遗传原因。虽然临床和组织学观察表明，NPH是由于正常排泄管功能丧失所致，但其发病机制仍不清楚。最近在大多数NPH病例中分离到一个突变的人类基因，并测定了其编码蛋白(“肾囊蛋白”)的序列。肾囊藻毒素的生化功能的一个线索是存在一个“Src同源3”(SH3)结构域，该结构域介导特定的蛋白质-蛋白质相互作用。对肾囊藻毒素的进一步研究将对NPH的发病机制有新的认识。在初步研究中，已经分离出编码小鼠肾囊藻毒素的cDNA，并在植入后小鼠胚胎发育过程中以及包括肾脏在内的各种成年组织中检测到了转录本。通过鉴定酪氨酸激酶底物pl30Cas作为一种与肾囊蛋白SH3结构域结合的蛋白，以及通过证明肾囊蛋白定位于极化上皮细胞的侧膜，获得了关于肾囊蛋白生化功能的新信息。这些观察结果导致了我们的普遍假设，即肾囊藻毒素在肾小管上皮细胞的形态发生和/或维持中起作用，需要与pl30Cas和其他参与细胞黏附相互作用的蛋白质发生特定的相互作用。为了验证和扩展这一假说，提出了以下具体目标：1)确定肾囊藻毒素在发育中的小鼠胚胎和成年肾脏中的表达空间模式；2)进一步鉴定和鉴定相关的肾囊藻毒素相互作用蛋白；3)确定肾囊藻毒素对黏附调节的p130Cas酪氨酸磷酸化和上皮细胞紧密连接形成和小管形成的影响。