CALCIUM TRANSPORT, BONE CELL FUNCTION, AND AGING

骨是一种动态的组织，保持恒定的流动状态。 在成年期的大部分时间里，由于 成骨细胞介导的骨形成和 骨细胞控制骨吸收。 这种“平衡”的结果 从描述新骨的“耦合”现象 形成响应于骨吸收，反之亦然。 它有 据推测，骨质疏松症和年龄相关的变化， 在由成骨细胞功能缺陷引起骨量中，和/或 在“耦合”过程中获得的变化。 使用“假定” 啮齿动物成骨细胞模型，其特征的复杂性， 成骨细胞功能、生长和分化的控制是 逐渐被解开。 控制骨质疏松的因素 再吸收，如细胞分泌大量 还鉴定了骨附着部位氢离子。 一些已发表的观察结果也支持这一假设， 成骨细胞调节破骨细胞的数量和活性， 产生短程旁分泌因子;相反， 成骨细胞通过骨细胞活性控制骨形成 还有待详细研究。 与我们正在进行的 研究兴趣是与年龄相关的骨量变化， 钙的运输，以及我们项目过去的成就 项目的努力，实验协议中描述的这一点， 应用程序将解决：（1）钙营养激素的作用 对年轻和老年啮齿动物和人类成骨细胞的研究，重点是 调节细胞内钙控制、钙转运和 细胞生长和中性金属蛋白酶的产生， 蛋白酶抑制剂;（2）碱性的关键作用 作为成骨细胞活性指标和调节剂的磷酸酶 （3）骨矿化之间的相互关系; 1，25（OH）_2D_3对细胞分化的调控作用及其最新研究进展 发现控制细胞Ca 2+稳态;（4）序列 导致质子的扩增表达和极化的事件 骨细胞分化过程中的泵;和（5）调节 骨形成是骨细胞活性的结果， 强调与年龄相关的“耦合信号”变化。“为了 为了实现这一目标，我们计划利用大鼠和人体器官， 成骨细胞培养，肾小管细胞培养， 免疫细胞化学和原位杂交技术， 荧光探针和荧光分光光度计系统 设计用于定量细胞内钙和pH的图像分析 单细胞制剂中的瞬变。

Bone is a dynamic tissue maintained in a constant state of flux. During much of adult life overall bone mass remains constant due to a net balance between osteoblastic mediated bone formation and osteoclastic controlled bone resorption. This "balance" results from the phenomenon of "coupling" which describes new bone formation in response to bone resorption and vice versa. It has been postulated that osteoporosis and the age-related alterations in bone mass result from defective osteoblastic function and/or acquired changes in the "coupling" process. Using "putative" rodent osteoblastic models, the complexities which characterize the control of osteoblastic function, growth and differentiation are gradually being unraveled. Factors controlling osteoclastic bone resorption such as the cell's ability to secrete large amounts of hydrogen ion at bone attachment sites have also been identified. A number of published observations also support the hypothesis that osteoblasts regulate the number and activity of osteoclasts by producing short range paracrine factors; conversely, the modulation of osteoblastic controlled bone formation by osteoclastic activity has yet to be examined in detail. Consistent with our on-going research interests in age-related alterations in bone mass and calcium transport, and the past accomplishments of our Program Project endeavors, the experimental protocols described in this application will address: (1) the effect of calcitrophic hormones on young and aged rodent and human osteoblasts with emphasis on the regulation of intracellular calcium control, calcium transport and cell growth and the production of neutral metalloproteinases and proteinase inhibitors; (2) the critical role of alkaline phosphatase as an index of osteoblastic activity and as a modulator of bone mineralization; (3) the interrelationship between the control of cell differentiation by 1,25(OH)2D3 and its recently- discovered control of cell Ca2+ homeostasis; (4) the sequence of events leading to amplified expression and polarization of proton pumps during osteoclastic differentiation; and (5) the modulation of bone formation as a result of osteoclastic activity with emphasis on age-related changes in the "coupling signals." To accomplish this goal, we plan to utilize rat and human organs and osteoblastic cell cultures, renal tubular cell cultures, immunocytochemistry and in situ hybridization techniques, a variety of fluorescent probes and spectro-fluorometric systems with video image analysis designed to quantitate intracellular calcium and pH transients in single cell preparations.