Mechanisms of PTH Signal Transduction in Bone Cells

骨细胞中 PTH 信号转导机制

• 批准号: 6635023
• 负责人: Nicola C Partridge
• 金额: $ 30.2万
• 依托单位: UNIV OF MED/DENT NJ-R W JOHNSON MED SCH
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-01-01 至 2005-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6635023
• 关键词: G protein; biological signal transduction; cell proliferation; enzyme activity; gel mobility shift assay; gene expression; genetic transcription; hormone receptor; hormone regulation /control mechanism; immunoprecipitation; laboratory rat; mitogen activated protein kinase; osteoblasts; osteogenesis; parathyroid hormones; phosphorylation; protein kinase C; protein protein interaction; transfection; western blottings

DESCRIPTION (Adapted from the Applicant's Abstract): Parathyroid hormone (PTH) plays a central role in regulation of calcium metabolism but also has a role as an anabolic hormone for bone. The hormone appears to act through a single receptor on the osteoblast to elicit all of its skeletal effects, including its anabolic effects. We have shown that low concentrations of PTH (1012 and I 0" M) stimulate DNA synthesis and proliferation of osteoblastic cells in culture, and that this is due to selective activation of protein kinase C (PKC) resulting in activation of extra-cellular signal regulated kinases (ERKs). The most likely reason is because these concentrations of PTH interact with their receptor in such a way as to selectively activate certain Ga proteins (such as Gaq or Ga 2/13) leading to activation of PKC. The activation and role of this pathway has not been well documented in the osteoblast. Thus, the overall goal of the present competing renewal is to delineate how low concentrations of PTH signal through PKC and what the eventual targets of ERK activation are which lead to proliferation of osteoblastic cells. This will be done as a two-pronged approach: 1. determining how low concentrations of PTH signal though PKC in osteoblastic cells by: a) ascertaining the type of PKC isozyme activated by low concentrations of the hormone, b) assessing the signal transduction pathway activating the PKC isozyme(s), c) determining the G protein activating the particular phospholipase(s). 2. delineating the eventual targets of ERK activation which lead to proliferation of osteoblastic cells by: a) examining whether known ERK target genes are affected by treatment of osteoblastic cells with low concentrations of PTH, b) identifying other genes regulated by low concentrations of PTH, c) examining whether the changes in mRNA for the gene(s) are reflected in changes in protein levels, d) ablating the regulated gene(s) by either using dominant negative forms of the protein or inducible anti-sense RNA, and ascertaining if this prevents enhanced proliferation of osteoblastic cells by low doses of PTH. The results of this work will provide insight into one of the key pathways of regulation of the osteoblast. In so doing, the data may provide a foundation for development of small molecules that can be used in place of injected PTH for treatment of osteoporosis.

描述（改编自申请人的摘要）：甲状旁腺激素（PTH） 在调节钙代谢方面起着核心作用，但也具有 骨骼的合成代谢激素。激素似乎通过单一作用 成骨细胞上的受体引起其所有骨骼作用，包括其骨骼作用 合成代谢效应。我们已经证明了低浓度的PTH（1012和I 0” m）刺激成骨细胞在培养中的DNA合成和增殖， 这是由于蛋白激酶C（PKC）的选择性激活所致 导致细胞外信号调节激酶（ERK）的激活。这 最有可能的原因是因为这些PTH的浓度与它们相互作用 受体以选择性激活某些GA蛋白的方式（例如 GAQ或GA 2/13）导致PKC的激活。激活和作用 在成骨细胞中，途径尚未得到充分记录。因此，总体目标 当前竞争的续约是描述pth浓度的低点 通过PKC信号以及ERK激活的最终目标是什么 导致成骨细胞的扩散。这将作为两个占有的 方法：1。确定PTH信号虽然PKC的低浓度 通过：a）确定低下的PKC同工酶的类型 激素的浓度，b）评估信号转导途径 激活PKC同工酶（s），c）确定G蛋白激活G蛋白 特定的磷脂酶。 2。描述ERK的最终目标 激活导致成骨细胞的增殖：a）检查 已知的ERK靶基因是否受成骨细胞的治疗影响 pth浓度低，b）识别由低低的基因 pth的浓度，c）检查基因mRNA的变化是否变化 反映在蛋白质水平的变化中，d）消融调节的基因 通过使用蛋白质的显性阴性形式或诱导的抗渗透 RNA，并确定这是否防止了成骨细胞的增殖 细胞通过低剂量的PTH。这项工作的结果将为您提供洞察力 成骨细胞调节的关键途径之一。这样做数据 可能为开发小分子的发展提供基础 注射PTH的位置用于治疗骨质疏松症。