Role of PLC in PTH Signaling: Mutant Receptors in Vivo

PLC 在 PTH 信号传导中的作用：体内突变受体

基本信息

批准号：
7325709
负责人：
HENRY M. KRONENBERG
金额：
$ 30.68万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-12-01 至 2008-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7325709
关键词：
25-hydroxyvitamin D Affect Age Alkaline Phosphatase Animals Apoptosis Biological Assay Blood Bone Resorption Bromodeoxyuridine C57BL/6 Mouse CDKN1C gene Calcium Calvaria Cell surface Cells Chondrocytes Collagen Collagen Receptors Creatinine clearance measurement Cyclic AMP DEXA DNA Development Diet Distal Employee Strikes Epiphysial cartilage Erinaceidae Family Femur Genes Goals Homeostasis Hydroxylation Hypercalcemia Hyperparathyroidism Immunofluorescence Immunologic In Situ Hybridization In Vitro Injection of therapeutic agent Kidney Ligands Macrophage Colony-Stimulating Factor Measurement Measures Mediating Messenger RNA Metatarsal bone structure Methods Mixed Function Oxygenases Modeling Molecular Mus Mutation Neonatal Osteocalcin Osteogenesis Osteoporosis PTHLH gene Parathyroid Hormone Receptor Pathway interactions Phenotype Phospholipase C Phosphorus Physiological Proteins Protocols documentation Rate Receptor Gene Receptor Signaling Regulation Reverse Transcriptase Polymerase Chain Reaction Role Second Messenger Systems Signal Pathway Signal Transduction TRANCE protein TdT-Mediated dUTP Nick End Labeling Assay Time Tissues Vitamin D Week Western Blotting Work bone brush border membrane calcium phosphate crosslink design follow-up in vivo inhibitor/antagonist inorganic phosphate insight kidney cell mutant novel parathyroid hormone-related protein pyridinoline receptor research study response second messenger sodium phosphate substantia spongiosa tibia urinary

项目摘要

The PTH/PTHrP receptor works through at least two distinct signaling pathways by activation both Gs and the Gq family. Previous studies have provided suggestive but inconclusive evidence concerning the linkage of specific second message pathways and particular distal actions of PTH and PTHrP in kidney and bone. The goal of this proposal is to establish the physiologic roles of specific second messenger pathways in PTH and PTHrP action in vivo. Lines of mice have been established in which the normal PTH/PTHrP receptor gene is replaced with a mutant receptor gene. In this mutant receptor, the alteration of four adjacent residues leads to dramatic blunting of activation of Gq without affecting the activation of Gs. Analysis of the effects of inactivating the Gq pathway on tissue responsiveness in intact animals will establish the physiologic roles of the Gq pathway in the actions of PTH and PTHrP. The results may help in the design of ways to control hypercalcemia and to use the anabolic actions of PTH to treat osteoporosis. Specific Aim I of the proposal will be to determine the role of PLC signaling by the PTH/PTHrP receptor in the growth plate, following up the discovery that these mice have abnormal growth plates. Specific Aim II will evaluate the effects of the mutation on the bone responses to PTH. Particular focus will be placed on the regulation of the anabolic effect of PTH and the stimulation by PTH of bone resorption. Specific Aim III will study the effects of the mutation on the renal responses to PTH, since calcium and phosphorus homeostasis are disrupted when these mice are challenged with a low calcium diet. Particular focus will be placed on the regulation of sodium-phosphate co-transport and of 25-hydroxyvitamin D 1alpha-hydroxylation.

PTH/PTHrP 受体通过激活 Gs 和 Gq 家族，通过至少两条不同的信号传导途径发挥作用。先前的研究提供了关于特定第二信息通路与 PTH 和 PTHrP 在肾脏和骨骼中的特定远端作用之间的联系的提示性但非决定性的证据。本提案的目标是确定特定第二信使途径在 PTH 和 PTHrP 体内作用中的生理作用。已经建立了正常 PTH/PTHrP 受体基因被突变受体基因取代的小鼠品系。在这种突变受体中，四个相邻残基的改变导致 Gq 的激活急剧减弱，但不影响 Gs 的激活。分析 Gq 通路失活对完整动物组织反应性的影响将确定 Gq 通路在 PTH 和 PTHrP 作用中的生理作用。结果可能帮助设计控制高钙血症和利用 PTH 的合成代谢作用来治疗骨质疏松症的方法。该提案的具体目标 I 是继发现这些小鼠生长板异常后，确定生长板中 PTH/PTHrP 受体的 PLC 信号传导的作用。具体目标 II 将评估突变对骨骼对 PTH 反应的影响。将特别关注 PTH 合成代谢作用的调节以及 PTH 对骨吸收的刺激。 Specific Aim III 将研究突变对肾脏对 PTH 反应的影响，因为当这些小鼠受到低钙饮食的挑战时，钙和磷的稳态会被破坏。将特别关注钠-磷酸盐共转运和 25-羟基维生素 D 1α-羟基化的调节。