RAMP Involvement in PTH Regulation of Bone Metabolism

描述(由申请人提供)：这项拟议研究的目标是为首席研究员Jeanne M.Nervina，DMD，PhD，提供作为一名独立研究人员的机会，以补充她在正畸方面的临床培训。她的培训将在该项目赞助商Sotirios Tetradis博士和Harvey Herschman博士的指导下进行。内尔维纳博士的职业目标是追求学术生涯，成为一名独立的牙医科学家，从事分子生物学研究，指导各级学生，并实践正畸。 骨的质量和数量是口腔面部病理的重要指标，也是许多牙科外科手术结果成功的预测因素。成骨细胞和骨吸收破骨细胞的解偶联活动会引起骨代谢的显著变化。我们的理论基础是，了解骨代谢的分子机制将极大地影响医学和牙科。甲状旁腺激素(PTH)对骨骼有显著的合成代谢作用，但我们还不清楚这些作用的分子介体。我们已经确定受体活性修饰蛋白3(RAMP3)是甲状旁腺素诱导的小鼠成骨细胞的主要基因。在初步研究中，我们发现PTH也调节小鼠成骨细胞中RAMP1的mRNA水平，但不调节RAMP2的mRNA水平。RAMP1、2和3是降钙素和降钙素受体样受体的关键共激活剂。这些受体的配体对骨骼有显著的合成代谢作用。我们推测RAMP蛋白参与甲状旁腺素对成骨细胞的合成代谢作用。为了检验我们的假设，我们提出了三个具体目标。(1)研究甲状旁腺激素对小鼠成骨细胞RAMP1和RAMP3基因表达的影响。(2)构建表达RAMP1和RAMP3基因的腺病毒，研究这些基因在成骨细胞表型调控中的作用。(3)利用COL1A1启动子构建RAMP1和RAMP3转基因小鼠，靶向成骨细胞进行转基因表达。将在大体、细胞和分子水平上研究每个小鼠品系的骨表型变化。这些研究将有助于我们了解甲状旁腺激素诱导RAMP1和RAMP3基因表达的机制，并揭示这些基因对成骨细胞功能的影响。

DESCRIPTION (provided by applicant): The goal of this proposed study is to provide the Principal Investigator, Jeanne M. Nervina, DMD, PhD, with the opportunity to develop as an independent researcher to complement her clinical training in orthodontics. Her training will be conducted under the guidance of the project's sponsors, Dr, Sotirios Tetradis and Dr. Harvey Herschman. Dr. Nervina's career goal is to pursue an academic career and establish herself as an independent dentist scientist conducting molecular biology research, mentoring students at all levels, and practicing orthodontics. Bone quality and quantity are important indicators of orofacial pathology and are predictors of outcome success for many dental surgical procedures. Uncoupled activity of bone forming osteoblasts and bone resorbing osteoclasts produce significant changes in bone metabolism. Our rationale is that understanding the molecular mechanisms of bone metabolism will greatly impact medicine and dentistry. Parathyroid hormone (PTH) has significant anabolic effects on bone, yet we do not understand the molecular mediators of these effects. We have identified receptor activity modifying protein 3 (RAMP3) as a PTH-induced primary gene in mouse osteoblasts. In preliminary studies we found that PTH also regulates RAMP1, but not RAMP2, mRNA levels in mouse osteoblasts. RAMP1, 2, and 3 are critical coactivators of calcitonin and calcitonin receptor-like receptors. Ligands for these receptors have significant anabolic effects on bone. We hypothesize that RAMP proteins participate in PTH's anabolic effect on osteoblasts. To test our hypothesis we propose three Specific Aims. (1) We will characterize PTH-induced RAMP1 and RAMP3 gene expression in mouse osteoblasts in vitro and in vivo. (2) Adenoviruses expressing RAMP1 and RAMP3 will be generated to assess the role of these genes in regulating osteoblast phenotype. (3) RAMP1 and RAMP3 transgenic mice will be generated using the COL1A1 promoter to target transgene expression to osteoblasts. Each mouse line will be studied for changes in bone phenotype at the gross, cellular, and molecular levels. These studies will help us understand the mechanisms of PTH-induced RAMP1 and RAMP3 gene expression and they will unveil the impact of these genes on osteoblast function.