FGFR2 IN SKELETOGENESIS--MUTATIONAL ANALYSIS IN MICE

FGFR2 在骨骼发生中的作用——小鼠突变分析

• 批准号: 6320186
• 负责人: HYUN-DUCK NAH-CEDERQUIST
• 金额: $ 7.93万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6320186
• 关键词: apoptosis; biological signal transduction; cell differentiation; cell growth regulation; cell proliferation; craniofacial; craniosynostosis; fibroblast growth factor; flow cytometry; gene mutation; gene targeting; genetically modified animals; growth factor receptors; histology; laboratory mouse; mitogen activated protein kinase; morphometry; normal ossification; osteoblasts; osteogenesis; phenotype; receptor expression; western blottings

DESCRIPTION: (Provided by Applicant) The development of the craniofacial skeleton with its interposed sutures involves a complex process, for which molecular and cellular regulatory mechanisms are not well understood. Recent genetic studies have linked various activating mutations in the fibroblast growth factor receptor 2 (FGFR2) gene to a subset of craniosynostosis syndromes, which have in common craniofacial skeletal deformities associated with the premature fusion of cranial sutures. This suggests that FGFR2 may play important roles in skeletal and sutural development. To further develop this notion, the investigators have introduced bone-targeted mFGFR2 transgene constructs, containing an activating mutation (Pro253Arg; an Apert mutation) or a dominant negative mutation, into the mouse germ line and generated several lines of transgenic mice. Initial analyses of these mice revealed that those with an activating mutation manifested some of the typical craniofacial features of craniosynostosis patients. The mice with a dominant negative mutation also displayed a variety of skeletal abnormalities, but they were distinctively different from the craniosynostosis phenotype. Based on pro- mitogenic and anti-apoptotic responses to FGF signaling in bone cells, the investigators hypothesize that an activating FGFR2 mutation promotes proliferation of osteoblasts, while suppressing apoptosis in these cells, resulting in uncontrolled bone formation and, ultimately, suture fusion. In contrast, loss of normal FGFR activities may result in reduced bone cell proliferation with an increased rate of apopotosis, culminating in dystrophic bone and wide-open sutures. To test their hypothesis, the investigators will define the skeletal and suture phenotypes of newly generated transgenic mouse lines (Aim 1), investigate how these mutations alter bone cell functions associated with osteogenesis and suture formation (Aim 2), and finally determine whether the mitogene activated protein (MAP) kinase pathway is involved in some of the altered bone cell functions induced by FGFR2 mutations (Aim 3). Data collected from this pilot study will be used to develop hypotheses to be tested in a larger research project.

描述：（由申请人提供）颅面的发育 骨骼与其插入的缝线涉及一个复杂的过程， 分子和细胞调节机制还不清楚。最近 遗传研究已将成纤维细胞中的各种激活突变联系起来 生长因子受体2（FGFR 2）基因与颅缝早闭亚群 综合征，其中常见的颅面骨骼畸形相关 颅缝过早融合这表明FGFR 2可能 在骨骼和缝的发育中起重要作用。进一步发展 基于这一观点，研究人员将骨靶向mFGFR 2转基因 含有激活突变（Pro253 Arg; Apert突变）的构建体 或显性负突变，进入小鼠生殖系， 几种转基因小鼠。对这些小鼠的初步分析显示， 那些有激活突变的人表现出一些典型的颅面特征， 颅缝早闭患者的特征。显性阴性的老鼠 突变也显示出各种骨骼异常，但他们是 与颅缝早闭症表型明显不同。基于Pro- 骨细胞中FGF信号的促有丝分裂和抗凋亡反应， 研究人员推测，激活FGFR 2突变促进 成骨细胞的增殖，同时抑制这些细胞的凋亡， 导致不受控制的骨形成并最终导致缝合融合。在 相反，正常FGFR活性的丧失可能导致骨细胞减少， 细胞凋亡率增加，最终导致营养不良 骨头和大开口缝合为了验证他们的假设，研究人员将 确定新产生的转基因小鼠的骨骼和缝合表型 线（目的1），研究这些突变如何改变骨细胞功能 与骨生成和缝线形成相关（目的2），最后 确定是否有丝分裂基因活化蛋白（MAP）激酶途径， 参与FGFR 2突变诱导的某些骨细胞功能改变 (Aim 3）。从这项试点研究中收集的数据将用于制定 在一个更大的研究项目中测试假设。