Osteocytes and Mechano-Transduction

描述（由申请人提供）：骨细胞是骨中最丰富的细胞，据信在骨骼机械传感中起关键作用，由此它们响应于剪切力或应变力的变化来调节骨建模和重塑。尽管骨对其力学环境的响应是公认的，但对机械转导途径的潜在机制知之甚少。此外，最近的研究结果证明了骨细胞在磷酸盐稳态调节中的作用。使用机械活性或静态培养条件培养骨细胞，我们将测试SOST和FGF-23是机械感觉的重要调节剂的假设。最初的研究将致力于建立条件永生化骨细胞系，该细胞系来源于转基因小鼠，该转基因小鼠表达在GFP-1（已知仅在骨细胞中表达）控制下的荧光绿色蛋白（GFP），并携带温度敏感的永生化SV 40抗原。细胞将在3D支架上生长，并经受1g微重力（NASA水平生物反应器）或增加机械刺激（NASA垂直生物反应器）。然后，我们将研究的作用，SOST和FGF 23信号在骨细胞（静态和动态条件下），通过选择性沉默这些转录使用小干扰RNA（siRNA）。在这些条件下分析基因表达模式并测量硬化蛋白和FGF 23的分泌将提供对机械转导途径和矿物质离子调节（UH 2）的见解。最后，利用微重力环境和最小的流体剪切培养条件，只有板载的国际空间站（ISS），我们建议调查骨细胞的反应卸载条件（UH 3）。eOSTEO飞行硬件将根据国际空间站这次使命的目标进行相应的修改。该建议的执行伙伴是Calm Technologies和加拿大航天局。这些研究的结果可能对废用或固定相关的骨疾病的治疗具有重要意义。 公共卫生相关性：如果成功的话，这一建议将显着推进我们的机械力对骨细胞生物学的作用的知识，并进一步提高我们对这些细胞的理解。这些研究的结果可能对废用或固定相关的骨疾病的治疗具有重要意义。因此，它的相关性是高的骨骼生物学。

DESCRIPTION (provided by applicant): Osteocytes, the most abundant cells in bone, are believed to play a key role in skeletal mechanosensing whereby they modulate bone modeling and remodeling in response to changes in shear or strain forces. Although it is well-established that bone responds to its mechanical environment, the mechanisms underlying the mechano- transduction pathway are poorly understood. Moreover, recent findings have documented a role of osteocytes in the regulation of phosphate homeostasis. Using a mechanically active or static culture condition to culture osteocytes, we will test the hypothesis that SOST and FGF-23 are important regulators of mechano-sensation. Initial studies will be devoted to establish conditionally immortalized osteocytic cell lines derived from transgenic mice expressing the fluorescent green protein (GFP) under the control of DMP-1 (known to be expressed exclusively in osteocytes) and carrying the temperature-sensitive immortalizing SV40 antigen. Cells will be grown on 3D scaffold and subjected to 1g, microgravity (NASA horizontal bioreactor) or increase mechanical stimulation (NASA vertical Bioreactor). We will then investigate the role of SOST and FGF23 signaling in osteocytes (under static and dynamic condition) by selectively silencing these transcripts using small interfering RNAs (siRNA). Analysis of gene expression patterns under these conditions and measuring secretion of sclerostin and FGF23 will provide insights into mechano-transduction pathways and mineral ion regulation (UH2). Lastly utilizing the microgravity environment and minimal fluid shear culture conditions available only onboard of the International Space Station (ISS) we propose to investigate osteocytes responses to unloading conditions (UH3). The eOSTEO flight hardware will be modified accordingly to the aims of this ISS mission. Implementation Partner for this proposal are Calm Technologies and the Canadian Space Agency (CSA). Results derived from the studies proposed could have significant implications for therapy of bone disorders related to disuse or immobilization. PUBLIC HEALTH RELEVANCE: If successful this proposal will significantly advance our knowledge of the role of mechanical forces on osteocytes biology and further enhance our understanding of these cells. Results derived from the studies proposed could have significant implications for therapy of bone disorders related to disuse or immobilization. Thus, its relevance is high for skeletal biology.