GROWTH FACTOR REGULATION OF CRANIAL SUTURE MORPHOGENESIS

生长因子对颅缝形态发生的调节

• 批准号: 2806371
• 负责人: LYNNE A. OPPERMAN
• 金额: $ 0.3万
• 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/2806371
• 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，并涉及缝线的过早消失。 现在， 正常和异常缝线形态发生的机制不是 已知。 TGF-β3被发现对于维持缝线至关重要 正直。 这些研究的主要目标是建立 TGF-β3 维持颅骨缝的机制 未骨化状态，但允许它们充当骨骼生长中心。 由于高浓度的 TGF-β3 会刺激骨细胞增殖 和胶原蛋白的合成，在疾病进展的初期很重要 细胞转变为成骨细胞表型，提出以下假设。 为了使缝线保持未骨化，但仍可作为骨骼生长中心， 缝合线内的细胞群必须保持有丝分裂、补充 细胞成熟为成骨细胞。 TGF-β3 调节颅缝 颅缝作为骨生长中心的形态发生和维持 改变缝线内细胞增殖的速率。 高时 浓度下，TGF-β3 刺激细胞增殖和基质 缝合线内的产生，同时 TGF-β3 浓度下降 促进成骨细胞基因型的成熟，具有基质组织 和矿化。 设计了以下具体目标来测试这一点 假设：1）测试缝线内细胞的有丝分裂反应 TGF-beta3, 2) 通过以下方式确定细胞外基质的产生率 用TGF-beta3处理的颅骨缝合线和骨，3)测试是否去除 TGF-β3 促进骨形成过程中细胞向成骨细胞的进展 消除缝线并 4) 确认 TGF-β3 是否可以预防骨质疏松 体内大鼠颅骨缝合线的消除。 一个文化体系，其中 胎鼠颅骨缝合线经历正常的缝合形态发生 存在完整的硬脑膜，但在硬脑膜中经历骨性闭塞 没有硬脑膜，将被使用。 有丝分裂发生率和 增殖细胞群将通过氚化胸苷建立 吸收。 基质生产率将通过氚化确定 脯氨酸掺入胶原蛋白和非胶原蛋白中。 碱性 磷酸酶、Msx2 和骨钙素的产生将由 Northern 进行检查 印迹分析、原位杂交和 PCR。 建立机制 TGF-β3 通过调节缝合细胞功能将导致 了解生长因子在正常和异常中发挥的作用 缝线形态发生。