MECHANOTRANSDUCTION PATHWAYS IN CHONDROCYTE BIOSYNTHESIS

软骨细胞负责维持软骨细胞外 在正常关节中处于动态平衡状态的矩阵 降解和形成。在关节炎疾病中，这种平衡被打破。 母体就会分解。机械对…有深远的影响 软骨细胞的生物合成行为，这个项目的中心目标是 为了描述软骨细胞检测生理性的机制 机械信号，特别是流体流动，并将它们转换为 适当的生物合成反应。我们的中心假设是流体 流动诱导牛关节软骨细胞内钙离子/i峰，结果 既有细胞外钙离子的内流，也有IP/3的钙离子的释放。 敏感的细胞内储存，介导软骨细胞的生物合成。我们会 使用电生理学、 荧光成像和分子生物学技术对假说的研究 使用电生理、荧光成像和 分子生物学技术要完成四个具体目标。在……里面 特异性目标1和2我们将表征膜钙通道 软骨细胞及其在液体流动诱导的钙/i峰值中的作用。在……里面 具体目标3我们将确定G蛋白激活的作用，IP/3 流体流诱导的细胞内钙离子释放 钙离子浓度升高。在最终的具体目标中，我们将确定流体是否- 流动诱导蛋白多糖(PG)合成和aggrecan mRNA表达 由软骨细胞内钙离子i尖峰介导。这将通过以下方式实现 有无流动诱导PG合成的定量研究 破坏钙依赖机制的药物-- AIMS 1至3中确定的软骨细胞中的转导通路。 信息将使我们有可能开发药理工具来 调控软骨细胞钙离子途径及其生物合成行为 最终软骨基质的完整性。

Chondrocytes are responsible for maintaining cartilage extracellular matrix which, in the normal joint, is in dynamic equilibrium between degradation and formation. In arthritic diseases, this balance is upset and the matrix breaks down. Mechanical have a profound influence on chondrocyte biosynthetic behavior, and the central goal of this project is to characterize the mechanism by which chondrocytes detect physiological mechanical signals, in particular fluid flow, and transduce them into an appropriate biosynthetic response. Our central hypothesis is that fluid flow-induced Ca2+/i spiking in bovine articular chondrocytes, resulting from both influx of extracellular Ca2+, and release of Ca2+ from IP/3- sensitive intracellular stores, mediates chondrocyte biosynthesis. We will test this hypothesis using a combination of electrophysiological, fluorescent imaging and molecular biological techniques to hypothesis using a combination of electrophysiological, fluorescent imaging and molecular biological techniques to complete four specific aims. In specific aims 1 and 2 we will characterize membrane Ca2+ channels in chondrocytes and their roles in fluid flow-induced Ca2+/i spiking. In specific aim 3 we will determine the role of G-protein activated, IP/3 stimulated release of Ca2+ from intracellular stores in fluid flow-induced Ca2+i spiking. In the final specific aim we will determine whether fluid- flow induced proteoglycan (PG) synthesis and aggrecan mRNA expression is mediated by Ca2+i spiking in chondrocytes. This will be achieved by quantifying flow-induced PG synthesis in the presence and absence of pharmacological agents which disrupt the Ca2+ dependent mechano- transduction pathways in chondrocytes identified in aims 1 to 3. This information will give us the potential to develop pharmacological tools to modulate chondrocyte Ca2+ pathways, their biosynthetic behavior and ultimately the integrity of the cartilage matrix.