GROWTH FACTOR REGULATION OF CRANIAL SUTURE MORPHOGENESIS

生长因子对颅缝形态发生的调节

• 批准号: 2443693
• 负责人: LYNNE A. OPPERMAN
• 金额: $ 8.77万
• 依托单位: TEXAS A&M BAYLOR COLLEGE OF DENTISTRY
• 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 2001-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2443693
• 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有关 形态发生，并涉及缝线过早闭塞。 目前， 正常和异常缝线形态发生的机制并不 知道的 TGF-β 3被发现是维持缝合的必要条件。 完整 这些研究的主要目标是建立 TGF-β 3维持颅缝的机制 未骨化状态，但允许它们作为骨生长中心发挥作用。 由于高浓度的TGF-β 3刺激骨细胞增殖， 和胶原蛋白的合成，重要的是在最初阶段的进展， 细胞转化为成骨细胞表型，提出了以下假设。 为了使缝合线保持不骨化，但作为骨生长中心， 缝合线内的细胞群必须保持促有丝分裂， 细胞成熟为成骨细胞。 TGF-β 3调节颅缝 颅缝作为骨生长中心的形态发生和维持 改变缝合线内细胞增殖的速率。 在高 浓度，TGF-β 3刺激细胞增殖和基质 在缝合线内的生产，而TGF-β 3浓度下降 促进成熟为成骨细胞基因型，具有基质组织 和矿化。 以下具体目标旨在检验这一点 假设：1）测试缝线内细胞的促有丝分裂反应， TGF-β 3，2）通过以下方式确定细胞外基质产生速率： 用TGF-β 3处理颅骨缝和骨，3）测试是否去除 TGF-β 3促进骨形成过程中细胞向成骨细胞的进展 4）确认TGF-β 3是否能阻止骨 体内大鼠颅骨缝的闭塞。 一种文化体系， 胎鼠颅骨缝在下丘脑中经历正常的缝形态发生， 存在完整的硬脑膜，但在 将使用无硬脑膜。 有丝分裂率和 增殖细胞群将通过氚化胸苷建立 摄取。 基质生产率将由氚化的 脯氨酸掺入胶原蛋白和非胶原蛋白。 碱性 磷酸酶、Msx 2和骨钙素的产生将通过北方 印迹分析、原位杂交和PCR。 建立机制 TGF-β 3调节缝合细胞功能的机制将导致 了解生长因子在正常和异常生长中的作用 缝合线形态发生