OSTEOBLAST PHENOTYPE SUPPRESSION BY PARATHYROID HORMONE

甲状旁腺激素对成骨细胞表型的抑制

• 批准号: 2749618
• 负责人: RONALD W KATZ
• 金额: $ 13.07万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-09-16 至 2001-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2749618
• 关键词: cell differentiation; gene expression; genetic transcription; hormone regulation /control mechanism; laboratory rat; osteoblasts; osteopontin; parathyroid hormones; phenotype; polymerase chain reaction

DESCRIPTION: (Adapted from investigator's abstract) The application proposes to study the basis of the observation that chronic PTH administration suppresses osteoblast differentiation. To gain insights into the molecular mechanism involved in this hormone effect, the applicant has chosen to focus his attention on the osteopontin gene. Osteopontin is a component of the bone matrix that, based on in vitro cell culture studies using differentiating osteoblasts, is expressed at the transition of pre-osteoblasts into fully differentiated osteoblasts. Previous studies have shown that osteopontin gene transcription is inhibited by PTH, forskolin and cAMP analogues. The Osteopontin promoter has response elements for calcitriol (vitamin D3) and phorbol esters, but does not contain a cAMP response element. The hypothesis that the applicant proposes to test is that the downregulation of osteopontin gene expression by PTH is mediated via induction of inducible cAMP early repressors (ICERS). This gene has been shown to downregulate phorbol response elements. In order to test the hypothesis, the applicant proposes to use a well-characterized rat calvarial osteoblast cell line, IRC 10/30-myc1, to show that the phorbol ester response elements and the expression of ICERs are necessary and sufficient to provide the molecular signals for PTH suppression of osteopontin gene expression. The Specific Aims of the application are: 1) to show that AP-1 sites (phorbol response elements) are necessary and sufficient for PTH to suppress osteopontin gene transcription; 2) to demonstrate that PTH and cAMP induce the formation of ICER proteins in osteoblast cell lines; and 3) to demonstrate that overexpression of ICERs suppresses transcription from the osteopontin promoter.

描述：（改编自研究者摘要）申请 建议研究观察的基础上，慢性PTH 给药抑制成骨细胞分化。 感悟 这种激素效应的分子机制， 申请人选择将注意力集中在骨桥蛋白基因上。 骨桥蛋白是骨基质的一种成分，根据体外实验， 使用分化成骨细胞的细胞培养研究，表达于 前成骨细胞向完全分化的成骨细胞的转变。 以往的研究表明，骨桥蛋白基因转录是 抑制PTH，毛喉素和cAMP类似物。 骨桥蛋白启动子 对骨化三醇（维生素D3）和佛波醇酯具有响应元件， 但不含cAMP应答元件。 的假设 申请人建议测试的是骨桥蛋白的下调 PTH的基因表达通过诱导cAMP的诱导而介导， 阻遏物（ICERS）。 该基因已被证明下调佛波醇 响应元素。 为了验证这一假设，申请人 提出使用良好表征的大鼠颅骨成骨细胞系， IRC 10/30-myc 1，以表明佛波酯反应元件和 ICER的表达是必要和充分的， PTH抑制骨桥蛋白基因表达的分子信号。 本申请的具体目的是：1）显示AP-1位点 （佛波醇反应元件）是必要的和足够的PTH， 抑制骨桥蛋白基因转录; 2）证明PTH， cAMP诱导成骨细胞系中ICER蛋白的形成;和 3)为了证明ICER的过表达抑制转录， 从骨桥蛋白启动子。