Action of Anabolic Factors on Bone Formation in Mice

合成代谢因子对小鼠骨形成的作用

• 批准号: 7189060
• 负责人: Marja Marie Hurley
• 金额: $ 20.62万
• 依托单位: UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-15 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7189060
• 关键词: Affect; Age; Agonist; Alkaline Phosphatase; Anabolic Agents; Animals; Apoptosis; Apoptotic; Back; Bone Density; Bone Marrow; Bone Resorption; Bone remodeling; COL1A1 gene; Calcium; Calvaria; Caspase; Cell Proliferation; Cells; Coculture Techniques; Collagen Type I; Colony-forming units; Condition; Creatinine; Cultured Cells; Cyclic AMP; DNA; Deoxyuridine; Disruption; Dose; ERG gene; Equilibrium; FGF2 gene; FOS gene; Femur; Fibroblast Growth Factor; Fibroblast Growth Factor 2; Fibroblast Growth Factor Receptors; Fracture; Gene Expression; Genes; Genotype; Grant; Growth Factor; Human; In Situ Nick-End Labeling; In Vitro; Injection of therapeutic agent; Insulin-Like Growth Factor I; Insulin-Like Growth-Factor Binding Protein 1; Interleukin-6; Knockout Mice; Label; Lead; MAP Kinase Gene; MAPK14 gene; Marrow; Measures; Mediating; Messenger RNA; Methods; Molecular; Mus; Nodule; Numbers; Organ Culture Techniques; Osteoblasts; Osteocalcin; Osteoclasts; Osteogenesis; Parathyroid Hormone Receptor; Parathyroid Hormones; Pathway interactions; Pattern; Phosphorous; Phosphorylation; Phosphotransferases; Physiological; Production; Protein Kinase C; Proteins; RNA; Rate; Rattus; Receptor Activation; Rodent; Role; S-Phase Fraction; Serum; Signal Pathway; Signal Transduction; Signaling Molecule; Spleen; Stromal Cells; Supplementation; System; TNFSF11 gene; TdT-Mediated dUTP Nick End Labeling Assay; Therapeutic; Thymidine; Time; Urine; Vitamin D; aged; alizarin; bone; calcium metabolism; human PTH protein; in vivo; inhibitor/antagonist; insight; mRNA Expression; novel strategies; osteoclastogenesis; pro-apoptotic protein; receptor expression; repaired; research study; response; size; spine bone structure; tartrate-resistant acid phosphatase; type I collagen alpha 1

DESCRIPTION (provided by applicant): In vivo administration of parathyroid hormone (PTH) stimulates new bone formation in experimental animals and humans. Although IGF-1 mediates some of the effects of PTH in bone, the role of other growth factors has not been elucidated. PTH is an essential regulator of calcium metabolism and also has catabolic effects on bone. Similar to PTH, basic fibroblast growth factor (FGF-2) is a potent bone anabolic agent when administered to rodents in vivo and also stimulates osteoclast formation and bone resorption. We have shown that PTH increased FGF-2 and FGF receptor (FGFR) expression in cell cultures of osteoblastic cells as well as in bone organ cultures. We have shown that short term FGF-2 treatment of mouse bone marrow stromal cells increased PTH Receptor 1, IGF-1 and Runx-2 expression and mineralized bone nodule formation. Furthermore, our preliminary studies show that the ability of PTH to stimulate osteoclast formation in murine bone marrow cultures, to increase serum calcium and to increase bone formation in vivo are all significantly reduced in mice with disruption of the Fgf2 gene suggesting an important physiologic role for endogenous FGF-2 in some of the responses to PTH in bone. It is not clear whether the reduced anabolic response to PTH in the Fgf2-/- mice is due to effects on bone remodeling at the level of the osteoblast or the osteoclast. Preliminary studies show that the cAMP response to PTH is similar in marrow stromal cells (from both genotypes) grown under differentiation conditions. PTH stimulates osteoclast formation via activation of RANKL. Interestingly, the ability of RANKL to stimulate osteoclast formation and to activate p38MAP kinase that is important in osteoclast formation is also impaired in marrow cultures from the Fgf2 -/- mice. The focus of this grant is to determine the role of endogenous FGF-2 in PTH induced bone remodeling in mice. The overall hypothesis is that endogenous FGF-2 is a necessary co-factor for maximal anabolic and resportive effects of PTH in bone. Modulation of endogenous FGF-2 by PTH could have therapeutic implications. Specific Aim 1: To determine whether FGF-2 deficiency modulates the anabolic response to PTH. Specific Aim 2a. To assess whether FGF-2 deficiency affects PTH induced osteoblast proliferation, differentiation, apoptosis and bone nodule formation. Specific Aim 2b: To examine the effect Fgf2 deficiency on osteoclastogenesis in response to PTH in Fgf2-/- mice. Specific Aim 3: To determine whether Fgf2 deficiency alters key signaling molecules that mediate PTH induced responses in bone. The results of the proposed studies could increase our understanding of the molecular mechanism(s) of the effect of PTH on bone. If FGF2 is critical for the PTH anabolic effect, then analysis of this interaction could lead to a new approach to anabolic therapy

描述（由申请方提供）：甲状旁腺激素（PTH）的体内给药刺激实验动物和人体的新骨形成。虽然IGF-1介导了PTH在骨中的一些作用，但其他生长因子的作用尚未阐明。甲状旁腺素是钙代谢的重要调节剂，也对骨有分解代谢作用。与PTH类似，碱性成纤维细胞生长因子（FGF-2）在体内给予啮齿动物时是一种有效的骨合成代谢剂，也刺激破骨细胞形成和骨吸收。我们已经表明，PTH增加成骨细胞培养物以及骨器官培养物中FGF-2和FGF受体（FGFR）的表达。我们已经表明，小鼠骨髓基质细胞的短期FGF-2处理增加了PTH受体1、IGF-1和Runx-2的表达和矿化骨结节的形成。此外，我们的初步研究表明，PTH刺激破骨细胞形成在小鼠骨髓培养物中，以增加血清钙和增加骨形成在体内都显着减少在小鼠与Fgf 2基因的破坏表明一个重要的生理作用，内源性FGF-2在一些响应PTH在骨。目前尚不清楚Fgf 2-/-小鼠中对PTH的合成代谢反应降低是否是由于在成骨细胞或破骨细胞水平上对骨重建的影响。初步研究表明，cAMP对PTH的反应在分化条件下生长的骨髓基质细胞（来自两种基因型）中是相似的。PTH通过激活RANKL刺激破骨细胞形成。有趣的是，RANKL刺激破骨细胞形成和激活在破骨细胞形成中重要的p38 MAP激酶的能力在Fgf 2-/-小鼠的骨髓培养物中也受损。本研究的重点是确定内源性FGF-2在PTH诱导的小鼠骨重建中的作用。总体假设是内源性FGF-2是骨中PTH最大合成代谢和反应作用的必要辅助因子。PTH对内源性FGF-2的调节可能具有治疗意义。具体目标1：确定FGF-2缺乏是否调节对PTH的合成代谢反应。具体目标2a。探讨FGF-2缺乏是否影响PTH诱导的成骨细胞增殖、分化、凋亡和骨结节形成。具体目的2b：在Fgf 2-/-小鼠中检查Fgf 2缺乏对响应于PTH的破骨细胞生成的影响。具体目标3：确定Fgf 2缺乏是否改变介导骨中PTH诱导反应的关键信号分子。这些研究结果有助于我们进一步了解PTH对骨作用的分子机制。 如果FGF 2是PTH合成代谢作用的关键，那么分析这种相互作用可能会导致合成代谢治疗的新方法