PTH and Mineralization: Role of Matrix Gla Protein

PTH 和矿化：基质 Gla 蛋白的作用

• 批准号: 6905644
• 负责人: RAJARAM GOPALAKRISHNAN
• 金额: $ 7.18万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6905644
• 关键词: AP1 protein; RNA interference; binding sites; biological signal transduction; calcium binding protein; cyclic AMP; gene deletion mutation; genetic models; genetic promoter element; genetic transcription; genetically modified animals; hormone regulation /control mechanism; laboratory mouse; model design /development; normal ossification; nucleic acid sequence; osteoblasts; parathyroid hormones; protein biosynthesis; AP1 protein; RNA interference; binding sites; biological signal transduction; calcium binding protein; cyclic AMP; gene deletion mutation; genetic models; genetic promoter element; genetic transcription; genetically modified animals; hormone regulation /control mechanism; laboratory mouse; model design /development; normal ossification; nucleic acid sequence; osteoblasts; parathyroid hormones; protein biosynthesis

DESCRIPTION (provided by applicant): Mineralization of bone and teeth is a complex process controlled by the interplay between various nucleators and inhibitors of hydroxyapatite crystal formation. Among these proteins, matrix Gla protein (MGP) is the most important with in vivo evidence for a role in regulating mineralization. Recently, we showed that MGP is induced by parathyroid hormone (PTH), and this response might play a crucial role in PTH-mediated inhibition of mineralization in osteoblasts. However, the transcriptional mechanisms involved in PTH regulation of MGP are not known. Detailed knowledge of this regulation will help in understanding a factor that can be used as a target for preventive and therapeutic interventions for patients with mineralization defects. The overall goal of this project is to use genetic and molecular approaches to determine the importance of MGP in the regulation of osteoblast mineralization by PTH; and to determine the transcriptional mechanisms involved in this regulation. This project will test two hypotheses: (a) induction of MGP is responsible for the inhibition of mineralization seen in osteoblasts following parathyroid hormone treatment, and (b) stimulation of MGP is mediated through activation of second messenger(s) which regulate specific cis-acting response elements in the promoter of the MGP gene. The following two specific aims will be pursued: 1. Determine the response of Mgp-deficient or -suppressed osteoblasts to parathyroid hormone treatment, and 2. Identify the DNA response elements necessary for MGP responsiveness to parathyroid hormone in osteoblasts. Aim 1 will use both Mgp-deficient (Mgp -/-) mice and osteoblasts in which MGP synthesis is suppressed using RNAi to determine the regulation of mineralization by PTH. We expect that PTH treatment of MGP-deficient/suppressed osteoblasts will not inhibit mineralization. Aim 2 will characterize the MGP promoter to understand the regulatory mechanisms involved in PTH induction. We expect, based on our preliminary data that CRE and AP-1 sites are key to PTH induced transcription of MGP. Our long-range goal, which will be tested in a future R01 application, is to characterize specific transcriptional factors involved in PTH-mediated regulation of MGP, and perform detailed structure-function analyses of MGP as it relates to PTH-mediated inhibition of mineralization.

描述（由申请人提供）：骨和牙齿的矿化是一个复杂的过程，由羟基磷灰石晶体形成的各种成核和抑制剂之间的相互作用控制。在这些蛋白质中，基质GLA蛋白（MGP）是最重要的体内证据，证明在调节矿化中作用。最近，我们表明MGP是由甲状旁腺激素（PTH）诱导的，并且这种反应可能在PTH介导的成骨细胞中矿化抑制作用中起着至关重要的作用。但是，尚不清楚参与MGP PTH调节的转录机制。对该法规的详细了解将有助于理解一个可以用作矿化缺陷患者进行预防和治疗干预措施的因素。该项目的总体目标是使用遗传和分子方法来确定MGP在PTH调节成骨细胞矿化中的重要性。并确定该调节所涉及的转录机制。该项目将检验两个假设：（a）MGP诱导造成甲状旁腺激素治疗后在成骨细胞中看到的矿化化的抑制作用，以及（b）通过激活第二信使的激活介导MGP的刺激，从而调节了MGP基因的发起人中的特定CIS作用响应元素。将实现以下两个具体目的：1。确定MGP缺陷型或抑制成骨细胞对甲状旁腺激素治疗的反应，以及2。确定MGP对成骨细胞中甲状旁腺激素的反应所必需的DNA响应元素。 AIM 1将使用MGP缺陷型（MGP - / - ）小鼠和成骨细胞，其中使用RNAi抑制MGP合成来确定PTH对矿化的调节。我们期望PTH治疗MGP缺陷/抑制成骨细胞不会抑制矿化。 AIM 2将表征MGP启动子以了解PTH诱导涉及的调节机制。 我们期望根据我们的初步数据，CRE和AP-1位点是PTH诱导MGP转录的关键。我们的远程目标将在未来的R01应用中进行测试，是为了表征参与PTH介导的MGP调节的特定转录因素，并对MGP进行详细的结构 - 功能分析，因为它与PTH介导的矿物质抑制有关。