PTH/PTHRP RECEPTORS IN THE BIOLOGY OF ENDOCHONDRAL BONE

软骨内骨生物学中的 PTH/PTHRP 受体

基本信息

批准号：
2856769
负责人：
GINO V SEGRE
金额：
$ 35.1万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
1994
资助国家：
美国
起止时间：
1994-01-01 至 2000-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/2856769
关键词：
bone development developmental genetics gene expression genetically modified animals hormone receptor hormone regulation /control mechanism insulinlike growth factor laboratory mouse organ culture osteogenesis parathyroid hormone related protein parathyroid hormones receptor expression

项目摘要

Precise orchestration of myriad of event is necessary for normal skeletal development and maintenance of its integrity. This proposal focuses on endochondral bone formation and the roles parathyroid hormone (PTH), PTH- related peptide (PTHrP) and PTH/PTHrP receptors play in the complex interrelationships between the PTH/PTHrP system and skeletal growth factors and their receptors, and the several collagens and non- collagenous proteins that are integral to bone biology. PTHrP is essential for normal skeletal maturation, as evidenced by striking abnormalities in mice whose PTHrP gene have been largely deleted by homologous recombination (PTHrP-less). Recently, receptors that bind both PTH and PTHrP have been cloned from several species; they have the unique property of binding both a circulating hormone important to calcium homeostasis, and a presumed paracrine/autocrine peptide with obvious importance to bone biology. These receptors also activate multiple effector molecules, including adenylate cyclase and phospholipase C. Numerous growth factors have also been shown to impact critically on skeletal development and homeostasis; among these, current evidence suggests that members of the insulin-like growth factors (IGFs), transforming growth factor beta (TGFbeta), and bone morphogenetic proteins (BMPs) either regulate, or are regulated by the PTH/PTHrP system. We plan to use a variety of approaches to understand the mechanism by which PTH and PTHrP modulate skeletal expression of genes for these growth factors, and to define influences these growth factors have on PTHrP and PTH/PRHrP receptor mRNA and protein expression. These interrelationships will be explored by both morphological criteria and molecular biological approaches in several systems. Aim I details our initial descriptive analyses to characterize gene expression in late fetal skeletal development in normal rats, rats up to 46 weeks of age, both normal and PTHrP-less fetal mice, and in chondrocytic and osteoblastic cells in primary culture. We have developed systems which we can perturb to analyze these relationships at increasingly complex levels of organization--from primary cells in culture, to organ explants and intact integrating in vitro and in vivo studies, we expect to define mechanisms at the cellular and organ level and relate the relevance of these findings to the whole animal. Aim II mainly analyzes the effects of PTH (1-84) and PTHrP (1-141) on expression of genes for growth factors, several collagens and non-collagenous proteins. Aim III examines the reciprocal relationship; that is, the influences of these growth factors on expression of PTHrP and PTH/PTHrP receptor mRNA and protein. Greater understanding of skeletal homeostasis will, in turn, contribute to bone biology in general and lead to more rational therapy for diseases like osteoporosis.

无数事件的精确编排对于正常骨骼来说是必要的发展和维护其完整性。该提案的重点是软骨内骨形成及其作用甲状旁腺激素 (PTH)、PTH- 相关肽 (PTHrP) 和 PTH/PTHrP 受体在复合物中发挥作用 PTH/PTHrP 系统与骨骼生长之间的相互关系因子及其受体，以及几种胶原蛋白和非胶原蛋白是骨生物学不可或缺的一部分。 PTHrP 是对于正常骨骼成熟至关重要，这一点可以通过打击来证明 PTHrP 基因已被大量删除的小鼠的异常同源重组（PTHrP-less）。最近，结合的受体 PTH 和 PTHrP 均已从多个物种中克隆；他们有结合两种重要的循环激素的独特性质钙稳态，以及推测的旁分泌/自分泌肽对骨生物学的重要性显而易见。这些受体也会激活多种效应分子，包括腺苷酸环化酶和磷脂酶 C。许多生长因子也被证明会影响对骨骼发育和体内平衡至关重要；其中，当前有证据表明胰岛素样生长因子（IGF）的成员，转化生长因子β (TGFbeta) 和骨形态发生蛋白质 (BMP) 调节 PTH/PTHrP 或受 PTH/PTHrP 调节系统。我们计划使用多种方法来了解 PTH 和 PTHrP 调节基因骨骼表达的机制对于这些生长因子，并定义影响这些生长因子对 PTHrP 和 PTH/PRHrP 受体 mRNA 和蛋白表达有影响。这些将通过形态学标准和多个系统中的分子生物学方法。目标我详细介绍了我们的最初的描述性分析来表征后期的基因表达正常大鼠、46周龄以下的胎儿骨骼发育，正常小鼠和无 PTHrP 的胎儿小鼠，以及软骨细胞和原代培养中的成骨细胞。我们开发的系统我们可以以越来越复杂的方式分析这些关系组织水平——从培养的原代细胞到器官外植体以及完整的体外和体内研究整合，我们期望定义细胞和器官水平的机制，并将其相关性联系起来这些发现适用于整个动物。目标二主要分析效果 PTH (1-84) 和 PTHrP (1-141) 对生长基因表达的影响因子、多种胶原蛋白和非胶原蛋白。目标三检查相互关系；也就是说，这些因素的影响生长因子对 PTHrP 和 PTH/PTHrP 受体 mRNA 表达的影响蛋白质。对骨骼稳态的更多了解反过来将总体上对骨生物学做出贡献并导致更合理的治疗对于骨质疏松症等疾病。