Osteocyte Function and Effects of Mechanical Strain

描述(由申请人提供)： 尽管骨细胞占所有骨细胞的90%以上，但与其他骨细胞、成骨细胞和破骨细胞相比，人们对其功能知之甚少。骨细胞是理想的位于骨骼中的细胞，可以感知机械应变，并将这种应变转化为骨形成和骨吸收的信号。然而，骨细胞在骨模型和骨重建中调节应变效应的作用尚不清楚。该计划项目赠款是为了开发团队方法来确定骨细胞的功能和对机械应变的反应。需要检验的假设是，骨细胞感知机械应变并对其做出反应，进而发出信号，导致骨丢失、重塑、建模或病理修复。骨细胞将机械应变转换为信号的机制包括细胞内和细胞外信号以及骨细胞功能所必需和特异的基因表达。该计划项目的具体目标是：1)确定骨细胞感受到的导致骨量变化的机械应变水平；2)确定骨细胞感受到的导致骨量变化的机械应变水平。确定E11在骨细胞树突状突起的形成和功能中的作用，3)确定骨细胞半突的功能和调节，4)确定Dmp1在骨细胞中的功能，5)确定DMP1在骨细胞中的功能。将菌株的密度与基因表达和生物学反应相关联。实现这些特定目的的新方法包括使用类骨细胞系、表达荧光报告的原代骨细胞、使用生物工程技术测量单个骨细胞感知的应变、转基因技术、新的骨细胞陷窝系统成像方法、荧光图像分析来检测单个细胞中的基因表达以及体内有针对性地删除骨细胞中的基因以检测受机械应变调节的基因。该计划项目由在分子生物学、生物化学、细胞生物学和生物工程领域具有特定人才、培训和专业知识的研究人员组成，他们以多学科的方式合作，整合、改进和扩展检查骨细胞功能和对应变的反应的方法。通过实现这些具体目标所获得的知识将被应用于预防和治疗因固定、太空飞行、微损伤和骨质疏松等疾病状态而造成的骨丢失。

DESCRIPTION (provided by applicant): Although osteocytes make up over 90% of all bone cells, little is known about their function compared to other bone cells, the osteoblast and the osteoclast. The osteocyte is the cell ideally situated in bone to sense mechanical strain and translate that strain into signals for bone formation and bone resorption. However, the role of osteocytes in modulating strain effects on bone modeling and remodeling is unclear. This Program Project Grant was initiated to develop a team approach to determine the function of osteocytes and response to mechanical strain. The hypothesis to be tested is that osteocytes sense and respond to mechanical strain and in turn send signals that result in either bone loss, remodeling, modeling, or pathologic repair. The mechanisms whereby osteocytes translate mechanical strain into signals include intracellular and extracellular signaling and the expression of genes necessary and specific for osteocyte function. The specific aims of the program project are: 1) To determine the levels of mechanical strain sensed by the osteocyte that result in change of bone mass, 2). To determine the role of E11 in the formation and function of osteocytic dendritic processes, 3) To determine the function and regulation of hemichannels in osteocytes, 4) To determine the function of Dmp1 in osteocytes, and 5). To correlate magntitude of strain with gene expression with biological response. Novel approaches to accomplish these specific aims include the use of an osteocyte-like cell line, primary osteocytes expressing a fluorescent reporter, the use of bioengineering techniques to measure strain sensed by individual osteocytes, transgenic technology, novel means of imaging the osteocyte lacuno-canalicular system, fluorescent image analysis to examine gene expression in single cells and targeted deletion of genes in osteocytes in vivo to examine genes regulated by mechanical strain. This program project is composed of investigators with specific talents, training and expertise in the areas of molecular biology, biochemistry, cell biology and bioengineering who together work in a multidisciplinary manner to integrate, improve, and expand approaches to examine osteocyte function and response to strain. Knowledge gained from the accomplishment of these specific aims will be applied to the prevention and treatment of bone loss due to immobilization, space flight, microdamage, and disease states such as osteoporosis.