COLONY STIMULATING FACTOR 1--REGULATION AND ROLE IN BONE

集落刺激因子 1——在骨中的调节和作用

• 批准号: 2331435
• 负责人: ELEANOR C WEIR
• 金额: $ 18.04万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-02-01 至 1999-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2331435
• 关键词: 1,25 dihydroxycholecalciferol; calcium; colony stimulating factor; cyclic AMP; gene expression; glycoprotein biosynthesis; growth factor receptors; hormone regulation /control mechanism; interleukin 1; laboratory mouse; laboratory rat; messenger RNA; northern blottings; nuclear runoff assay; osteoblasts; osteopetrosis; osteoporosis; parathyroid hormones; physiologic bone resorption; protein kinase C; receptor expression; tissue /cell culture; tumor necrosis factor alpha; tumor necrosis factor beta; western blottings

DESCRIPTION: (Adapted From Investigator's Abstract) The osteoblast, in addition to forming bone, plays a central role in bone resorption. Although the precise mechanism by which osteoblasts mediate osteoclastic bone resorption is unclear, one widely held hypothesis is that in response to bone resorbing agents, osteoblasts secrete cytokines which activate osteoclasts or their precursors. While the nature of these cytokines is unknown, one potential candidate is colony stimulating factor-1 (CSF-1). There is substantial in vivo and in vitro evidence that CSF-1 is critically important for both the proliferation and differentiation of osteoclast progenitors: (1) deficiency of CSF-1 in vivo causes osteopetrosis in the op/op mouse; (2) CSF-1 stimulates osteoclast formation and bone resorption in vitro; and (3) CSF-1 is the principal colony stimulating activity secreted by osteoblasts in response to parathyroid hormone (PTH). Although there is mounting evidence for osteoblast-derived CSF-1's role in osteoclast development, little is known regarding the regulation of CSF-1 gene expression in osteoblasts, or the isoforms of CSF-1 which are synthesized and secreted by osteoblasts. In addition, the precise physiologic role of CSF-1 in normal bone remodeling is poorly understood. The applicants have recently demonstrated that tumor necrosis factor (TNF) and PTH increase CSF-1 gene expression and protein release in osteoblasts by a transcriptional mechanism. They plan to pursue these observations by characterizing cis acting elements by which PTH and TNF induce CSF-1 gene expression, and examining potential transcription factors mediating this response, using a combination of deletional analysis and nuclear protein-DNA binding studies. They have also demonstrated by flow cytometry and by PCR analysis of reverse- transcribed RNA that osteoblasts express a cell surface form of CSF-1, which is increased by TNF treatment. They will, therefore, extend this observation by examining the relative expression, regulation and biological significance of the soluble and cell surface forms of CSF-1. For these studies they will characterize the mRNA and protein species of CSF-1 which are synthesized, processed and released by untreated and TNF-treated osteoblasts, and will examine the effects of the soluble and cell-surface forms of CSF-1 on osteoclast formation. Finally, they will examine the role of CSF-1 in bone remodeling in vivo by developing and analyzing a transgenic mouse with targeted over-expression of CSF-1 in osteoblasts. Taken together, these studies should elucidate CSF-1's regulation and role in bone and may improve the understanding of basic mechanisms of bone resorption.

描述：（根据调查员的摘要改编）成骨细胞， 除了形成骨骼，在骨吸收中起着核心作用。 虽然成骨细胞介导整骨的精确机制 骨吸收尚不清楚，一个广泛持有的假设是 对骨吸收剂的反应，成骨细胞分泌细胞因子，这些因子 激活破骨细胞或其前体。 而这些的本质 细胞因子尚不清楚，一个潜在的候选者是菌落刺激 因子1（CSF-1）。 体内和体外证据有大量 CSF-1对于增殖和 破骨细胞祖细胞的分化：（1）CSF-1缺乏 体内引起OP/OP小鼠的骨质骨毒性； （2）CSF-1刺激 体外破骨细胞形成和骨吸收； （3）CSF-1是 主要菌落刺激成骨细胞分泌的活性 到甲状旁腺激素（PTH）。 虽然有越来越多的证据证明 成骨细胞衍生的CSF-1在破骨细胞开发中的作用，几乎没有 已知有关成骨细胞中CSF-1基因表达的调节， 或由CSF-1的同工型合成和分泌的CSF-1 成骨细胞。 另外，CSF-1在 正常的骨头重塑知之甚少。 申请人最近证明了肿瘤坏死因子 （TNF）和PTH增加CSF-1基因表达和蛋白质释放 成骨细胞通过转录机制。 他们计划追求这些 通过表征pth和tnf的顺式作用元素来观察 诱导CSF-1基因表达并检查电位转录 使用缺失的组合，介导这种反应的因素 分析和核蛋白-DNA结合研究。 他们也有 通过流式细胞仪和反向分析证明 成骨细胞表达CSF-1的细胞表面形式的转录RNA， TNF治疗增加了。 因此，他们将扩展这一点 通过检查相对表达，调节和 CSF-1的可溶性和细胞表面形式的生物学意义。 对于这些研究，它们将表征mRNA和蛋白质物种 由未经处理的CSF-1合成，处理和释放的CSF-1 TNF处理的成骨细胞，并将检查可溶性和 CSF-1在破骨细胞形成上的细胞表面形式。 最后，他们会的 通过发展和 用针对CSF-1的靶向过表达分析转基因小鼠 成骨细胞。 综上所述，这些研究应阐明CSF-1 调节和在骨骼中的作用，并可能提高对基本的理解 骨吸收机制。