Role of mechanical strain in GAP junctions in osteocytes

骨细胞是一种机械感觉细胞，参与调节骨形成的质量和结构。认为骨细胞向破骨细胞发出信号以诱导骨吸收，并且成骨细胞开始骨形成。这些重塑过程的协调部分地由细胞间间隙连接介导的细胞间通讯介导，所述细胞间通讯将机械信号传递到骨形成和重塑所必需的其他骨细胞。本申请的目的是了解间隙连接通道在骨细胞中调节机械应力刺激信号中的作用。该项目的中心假设是间隙连接介导的细胞间通讯是介导和协调机械负荷产生的信号的主要途径之一。这一假设已制定强有力的初步研究结果的基础上，这表明，间隙连接是必不可少的介导的骨细胞细胞对机械应力的反应，骨细胞之间的间隙连接介导的细胞间通讯刺激的存在下施加的应变。要检验的中心假设和应用程序的目标将通过追求四个具体目标来实现：1）。证实缝隙连接在骨细胞对流体流动诱导的机械应力的反应中发挥的重要作用; 2）。鉴定和表征负责骨细胞中功能性间隙连接通道形成的连接蛋白; 3）.确定流体流动是否比机械拉伸在调节骨细胞中的间隙连接功能方面更有效，以及4）。确定前列腺素E2是否调节骨细胞间隙功能对流体流动诱导的剪切应力的反应。拟议的研究是创新的，因为骨细胞样细胞系将被用作主要的模型系统与补充实验，使用原代骨细胞培养。此外，这项研究将全面的生物化学，分子，遗传和功能方法与独特的机械工程应用相结合。我们期望我们的实验结果将对我们理解机械应变产生的信号如何在骨细胞和骨微环境的其他细胞元素之间协调产生重大影响。结果将是重要的，因为这一新的知识将有助于扩大我们的理解如何机械信号在骨细胞中转导和调制。 此外，这项研究活动应有助于预防/治疗骨质疏松症等骨疾病的一般策略，并为药物开发和发现提供新的思路和潜在的分子靶点。

Osteocytes embedded in the matrix of bone are thought to be mechanosensory cells involved in the regulation of both the mass and structure of bone formation. The osteocyte is thought to signal the osteoclast to induce bone resorption and the osteoblast to begin bone formation. Coordination of these remodeling processes is mediated, in part, by cell-to-cell gap junction-mediated intercellular communication in transmitting mechanical signals to the other bone cells essential for bone formation and remodeling. The objective of this application is to understand the role that gap junction channels play in regulating the signals stimulated by mechanical stress in osteocytes. The central hypothesis of the project is that gap junction-mediated intercellular communication is one of the major pathways that mediate and coordinate the signals generated by mechanical loading. This hypothesis has been formulated on the basis of strong preliminary findings, which suggest that gap junctions are essential for mediating the osteocyte cell responses to mechanical stress, and that intercellular communication mediated by gap junctions between osteocytes is stimulated in the presence of the applied strain. The central hypothesis to be tested and the objective of the application will be accomplished by pursuing four specific aims: 1). Confirm the essential role that gap junctions play in osteocyte responses to mechanical stress induced by fluid flow; 2). Identify and characterize the connexin(s) responsible for formation of functional gap junction channels in osteocytes; 3). Determine if fluid flow is more effective than mechanical stretch in regulating gap junction function in osteocytes, and 4). Determine if prostaglandin E2 regulates osteocyte gap function response to shear stress induced by fluid flow. The proposed research is innovative, because osteocyte-like cell lines will be employed as the principal model system with complementary experiments using primary osteocyte cultures. Moreover, this study combines comprehensive biochemical, molecular, genetic and functional approaches with unique mechanical engineering applications. It is our expectation that our experimental findings will have a major impact on our understanding on how signals generated by mechanical strain are coordinated between the osteocytes and other cellular elements of the bone micro-environment. The outcomes will be significant because this new knowledge will contribute to broaden our understanding of how mechanical signals are transduced and modulated in osteocytes. Furthermore, this research activity should make a contribution to the general strategies for the prevention/treatment of bone diseases such as osteoporosis and to new ideas and potential molecular targets for drug development and discovery.