OCRL and the pathogenesis of Lowe Syndrome and Dent Disease

OCRL 与 Lowe 综合征和 Dent 病的发病机制

• 批准号: 7736230
• 负责人: Pietro De Camilli
• 金额: $ 31.78万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7736230
• 关键词: Address; Affect; Apical; Biochemical; Cell Line; Cell membrane; Cell physiology; Cells; Classification; Clathrin; Clathrin Adaptors; Clinical; Defect; Disease; Early Endosome; Endocytosis; Endosomes; Enzymes; Fanconi Syndrome; Foundations; Functional disorder; Genes; Goals; Golgi Apparatus; Homologous Gene; Inositol; Ion Channel; Kidney; Kidney Diseases; Knowledge; Laboratories; Link; Lipids; Medical; Membrane Proteins; Mental Retardation; Metabolism; Modeling; Molecular; Mus; Mutation; Oculocerebrorenal Syndrome; Organ; Pathogenesis; Pathology; Pathway interactions; Phosphatidylinositols; Phosphoric Monoester Hydrolases; Play; Positioning Attribute; Property; Protein Dephosphorylation; Proteins; Proximal Kidney Tubules; Recycling; Renal function; Renal tubule structure; Reporting; Role; Signal Transduction; Site; Sorting - Cell Movement; System; TFAP2A gene; Therapeutic; Work; congenital cataract; human disease; inositol-1,4,5-trisphosphate 5-phosphatase; kidney cell; novel; prevent; public health relevance; receptor; therapy design; therapy development; trafficking; treatment strategy

DESCRIPTION (provided by applicant): The long-term goal of this proposal is to develop therapeutic strategies for the treatment of two human diseases, Oculo-Cerebro-Renal syndrome of Lowe (Lowe syndrome) and Dent disease, which result from mutations in the gene encoding the inositol 5-phosphatase OCRL. Lowe syndrome is a severe X-linked disorder characterized by reabsorption defects in the kidney proximal tubule (renal Fanconi syndrome), mental retardation and congenital cataracts. Dent disease is another X-linked disorder in which the clinical manifestations are limited to kidney defects that are similar to those observed in Lowe syndrome. While it is known that the main function of OCRL is to dephosphorylate PI(4,5)P2 and PI(3,4,5)P3 at the 5 position of the inositol ring, the mechanisms through which a defect in this protein causes disease is unclear. The objective of this project is to elucidate these mechanisms in the kidney, as it is the organ consistently affected by mutations in the OCRL gene. Recent studies at the cellular level have suggested that the main site of action of OCRL is the early endocytic pathway, where several major OCRL interactors are concentrated, such as clathrin, the clathrin adaptor AP-2, Rab5 and the endocytic adaptor APPL1. A main working hypothesis is that abnormal levels of PI(4,5)P2, and possibly PI(3,4,5)P3, resulting from impaired OCRL function result in abnormal traffic and sorting of apical plasma membrane proteins in kidney proximal tubule cells. In this proposal we plan to further characterize the molecular properties and interactions of OCRL and of its homologue INPP5B, to elucidate the role of OCRL in endocytic traffic and endosomes dynamics in kidney proximal tubule cells and in model cell lines, to determine the impact of mutations in OCRL/INPP5B on kidney function in mice and to identify proteins whose function enhances or suppresses defects resulting from lack of OCRL. The identification of such modifier genes may provide clues relevant to understanding the impact of different OCRL mutations in Lowe syndrome and Dent disease and toward developing therapies for these conditions. Given the key role of PI metabolism and of the endosomal system in cell physiology and pathology, the results of these studies will be additionally relevant to the elucidation and treatment of a variety of diseases of the kidney as well as other organs. PUBLIC HEALTH RELEVANCE: OculoCerebroRenal Syndrome of Lowe (Lowe Syndrome) is a severe disorder characterized by kidney dysfunction, mental retardation and congenital cataracts, which results from mutations in the gene encoding a lipid metabolizing enzyme called OCRL. Mutations in OCRL can also cause Dent disease, whose clinical manifestations are limited to kidney defects that are similar to those observed in Lowe syndrome. The goal of this proposal is to understand how disruption of OCRL function leads to kidney disease with the hope that this information may help to develop therapeutic strategies for these conditions.

描述（由申请人提供）：该提案的长期目标是制定治疗两种人类疾病的治疗策略，即Lowe（Lowe综合征）的Oculo-Cerebro-肾脏综合征（Lowe综合征）和DENT疾病，这是由编码肌醇5-磷酸酶OCRL的基因突变引起的。 Lowe综合征是一种严重的X连锁障碍，其特征是肾脏近端小管（肾脏范科尼综合征），智力低下和先天性白内障中的重吸收缺陷。凹陷疾病是另一种X连锁疾病，其中临床表现仅限于与Lowe综合征相似的肾脏缺陷。众所周知，OCRL的主要功能是在肌醇环的5个位置上脱磷酸化Pi（4,5）P2和Pi（3,4,5）P3，但该蛋白质导致疾病缺陷的机制尚不清楚。该项目的目的是阐明肾脏中的这些机制，因为它是受OCRL基因突变影响的器官。细胞水平的最新研究表明，OCRL的主要作用部位是早期的内吞途径，其中几个主要的OCRL相互作用者被浓缩，例如网状蛋白，网状蛋白适配器AP-2，RAB5和内吞适配器Appl1。一个主要的假设是，由OCRL功能受损而导致的PI（4,5）P2和PI（3,4,5）P3的异常水平会导致肾脏近端肾小管细胞中的顶质质膜蛋白的流量异常和顶端质膜膜蛋白的排序。在该提案中，我们计划进一步表征OCRL及其同源物Inpp5b的分子特性和相互作用，以阐明OCRL在肾脏近端小管细胞和模型细胞系中的内吞交通和内体动力学中的作用，并在模型细胞系中，以确定对蛋白质和抑制kidney inte in Proun的影响，以确定其抑制蛋白质的蛋白质的影响。 OCRL。这种修饰基因的鉴定可能会提供与了解不同OCRL突变对Lowe综合征和凹陷疾病的影响以及针对这些疾病开发疗法的影响有关的线索。鉴于PI代谢和内体系统在细胞生理和病理学中的关键作用，这些研究的结果将与阐明和治疗肾脏以及其他器官的各种疾病有关。公共卫生相关性：Lowe（Lowe综合征）的眼脑综合征是一种严重疾病，其特征是肾功能障碍，智力低下和先天性白内障，这是由编码脂质代谢酶的基因突变引起的，称为OCRL。 OCRL中的突变也会引起凹陷疾病，其临床表现仅限于与Lowe综合征相似的肾脏缺陷。该提案的目的是了解OCRL功能的破坏如何导致肾脏疾病，希望此信息可以帮助制定这些疾病的治疗策略。