NHERF-Mediated PTH Signaling in Mineral Ion Homeostasis

NHERF 介导的 PTH 信号传导在矿物质离子稳态中的作用

• 批准号: 7160507
• 负责人: GINO V SEGRE
• 金额: $ 27.57万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-12-01 至 2008-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7160507
• 关键词: biological signal transduction; biomarker; bone; cell line; genetically modified animals; homeostasis; hormone receptor; hormone regulation /control mechanism; in situ hybridization; kidney; laboratory mouse; parathyroid hormone related protein; parathyroid hormones; phospholipase C; protein kinase C; sodium hydrogen exchanger

In its biological actions on bone and kidney and overall mineral ion homeostasis, PTH stimulates the PTH/PTHrP receptor and activates distinctive signalling pathways within target cells (including adenylyl cyclase, phospholipase C, phospholipase-C independent protein kinase C and calcium channels). Growing evidence that some of these distinctive pathways have discernable differences in bone and renal cell function has led to increased study of signal selectivity and its cellular role. Na+/H+exchange regulatory factors (NHERFs) (components of signal modulating intracellular scaffold proteins) have recently been shown by our group to act as "molecular switches" that increase activation by PTH of the PLC pathway and suppress the adenylyl cyclase pathway. A gene knockout of NHERF-1, performed by collaborators, has an osteopenic skeletal phenotype. NHERFs have now been identified in bone cell lines. An opossum kidney cell line (OK) which is deficient in NHERF lacks the usual PTH stimulated blockade of phosphate uptake. The deficiency is reversed and wild type OK cell line function restored by NHERF transfection. This cell line serves as a model of PTH-mediated inhibition of tubular re- absorption of phosphate. Our specific aims are therefore: AIM I. Analyze the functional role of NHERFs with respect to PTH signaling and cell morphology in an opossum kidney cell model, comparing cell lines that are NHERF intact, defective and repleted. AIM II. Study the role of the NHERF/PTH1R complex in PTH signaling in bone cell lines in vitro. AIM III. Study the role of NHERF-1 in mediating the actions of PTH in bone, both in vitro and in vivo, working with the NHERF- 1 -/- mice provided by our colleagues for assessment of cellular mechanisms responsible for the skeletal phenotype.

PTH在其对骨骼和肾脏的生物学作用以及整体矿物质离子稳态，刺激PTH/PTHRP受体，并激活靶细胞内的独特信号传导途径（包括腺苷酸环酶C，磷脂酶C，磷脂酶-C独立的蛋白质激酶C和钙通道）。越来越多的证据表明，这些独特的途径中的某些途径在骨骼和肾细胞功能方面具有可见的差异，导致对信号选择性及其细胞作用的研究增加。 Na+/H+交换调节因子（NHERFS）（NHERFS）（信号调节细胞内支架蛋白的组成部分）最近已显示我们的组充当“分子开关”，可增加PLC途径的PTH并抑制腺苷环酶途径。由合作者执行的NHERF-1的基因敲除具有骨质减少骨骼表型。现在已经在骨细胞系中鉴定出NHERF。缺乏NHERF的负鼠肾细胞系（OK）缺乏通常的PTH刺激磷酸盐摄取的封锁。缺乏症是通过NHERF转染恢复的野生型OK细胞线功能。该细胞系用作PTH介导的管状重新抑制的模型 磷酸盐的吸收。因此，我们的具体目的是：AIM I.分析NHERF在负鼠肾细胞模型中PTH信号传导和细胞形态方面的功能作用，比较了NHERF完整，有缺陷且填充的细胞系。目标II。研究NHERF/PTH1R复合物在体外骨细胞系中PTH信号传导中的作用。目标三。研究NHERF-1在体外和体内介导PTH在骨骼中的作用，与我们的同事提供的NHERF-1 - / - 小鼠一起评估负责骨骼表型的细胞机制。