GROWTH FACTOR REGULATION OF CRANIAL SUTURE MORPHOGENESIS

生长因子对颅缝形态发生的调节

• 批准号: 6176968
• 负责人: LYNNE A. OPPERMAN
• 金额: $ 10.18万
• 依托单位: TEXAS A&M UNIVERSITY HEALTH SCIENCE CTR
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-09-01 至 2003-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6176968
• 关键词: alkaline phosphatase; aminoacid metabolism; autoradiography; bone development; cell cycle; cell growth regulation; collagen; embryo /fetus tissue /cell culture; extracellular matrix; gene expression; genotype; in situ hybridization; laboratory rat; messenger RNA; neutralizing antibody; normal ossification; northern blottings; osteoblasts; osteocalcin; osteocytes; polymerase chain reaction; proline; protein biosynthesis; thymidine; transforming growth factors

Many severe craniofacial anomalies are associated with abnormal suture morphogenesis, and involve premature obliteration of sutures. Currently, the mechanisms underlying normal and abnormal suture morphogenesis are not known. TGF-beta3 was found to be essential for maintaining sutural integrity. The primary goal of these studies is to establish the mechanisms by which TGF-beta3 maintains calvarial sutures in their unossified state, yet allows them to function as bone growth centers. Since high concentrations of TGF-beta3 stimulate bone cell proliferation and collagen synthesis, important in the initial period of progression of cells to an osteoblast phenotype, the following hypothesis was formulated. For sutures to remain unossified, yet function as bone growth centers, a population of cells within the suture must remain mitogenic, replenishing cells maturing into osteoblasts. TGF-beta3 regulates cranial suture morphogenesis and maintenance of cranial sutures as bone growth centers by altering rates of cell proliferation within the suture. At high concentrations, TGF-beta3 stimulates cell proliferation and matrix production within the suture, while declining concentrations of TGF-beta3 promote maturation to an osteoblastic genotype, with matrix organization and mineralization. The following specific aims were designed to test this hypothesis: 1) test the mitogenic response of cells within the suture to TGF-beta3, 2) determine rates of extracellular matrix production by calvarial suture and bone treated with TGF-beta3, 3) test whether removal of TGF-beta3 promotes progression of cells to osteoblasts during bony obliteration of sutures and 4) confirm whether TGF-beta3 prevents osseous obliteration of rat calvarial sutures in vivo. A culture system in which fetal rat calvarial sutures undergo normal suture morphogenesis in the presence of intact dura mater, but undergo osseous obliteration in the absence of dura mater, will be used. Rates of mitogenesis and proliferating cell populations will be established by tritiated thymidine uptake. Rates of matrix production will be established by tritiated proline incorporation into collagen and non-collagen proteins. Alkaline phosphatase, Msx2 and osteocalcin production will be examined by northern blot analysis, in situ hybridization and PCR. Establishing the mechanisms by which TGF-beta3 regulates suture cell function will lead to an understanding of the role growth factors play in both normal and abnormal suture morphogenesis.

许多严重的颅面畸形与异常缝合有关。 形态发生，并涉及过早闭合缝线。目前， 正常和异常缝合形态发生的机制不是 为人所知。研究发现，转化生长因子-β3对维持缝合是必不可少的。 正直。这些研究的主要目标是建立 转化生长因子-β3维持颅骨缝合的机制 非骨化状态，但允许它们作为骨骼生长中心发挥作用。 由于高浓度的转化生长因子-β3刺激骨细胞增殖 和胶原合成，在血管进展的初始阶段很重要 细胞向成骨细胞表型转化时，提出了以下假设。 为了使缝合线保持非骨化状态，但又能起到骨生长中心的作用， 缝合线内的细胞群体必须保持有丝分裂，补充 细胞成熟为成骨细胞。转化生长因子-β3对颅缝的调节 颅缝作为骨生长中心的形态发生和维持 改变缝合线内的细胞增殖率。在高处 浓度，转化生长因子-β3刺激细胞增殖和基质 缝合内产生，同时转化生长因子-β3浓度下降 通过基质组织促进成骨基因的成熟 和矿化作用。为了测试这一点，我们设计了以下具体目标 假设：1)测试缝线内细胞的有丝分裂反应 转化生长因子-β3，2)通过以下方式确定细胞外基质的生成率 用转化生长因子-β3治疗的颅骨缝合和骨，3)测试是否去除 转化生长因子-β3促进成骨细胞向成骨细胞转化 缝线封闭和4)确认转化生长因子-β3是否阻止骨化 大鼠在体颅盖骨缝线的缝合。一种文化体系，其中 胎鼠颅骨缝在正常的颅骨缝形态发生 存在完整的硬脑膜，但在 无硬脑膜时，会用到。有丝分裂速率和 用氚胸腺嘧啶核苷建立增殖细胞群 领悟。基质的生产速度将通过氚测定来确定 在胶原蛋白和非胶原蛋白中掺入脯氨酸。碱性 磷酸酶、MSX2和骨钙素的产生将由Northern检测 印迹分析、原位杂交和聚合酶链式反应。建立机制 通过转化生长因子-β3调节缝合细胞功能将导致 理解生长因子在正常和异常中所起的作用 缝合形态发生。