CALCIUM TRANSPORT, BONE CELL FUNCTION, AND AGING

骨是维持在恒定流动状态中的动态组织。 在成人生活的大部分时间里，总体骨量保持不变 在成骨细胞介导的骨形成和骨形成之间达到净平衡 破骨细胞控制骨吸收。这种“平衡”的结果 从描述新骨的“偶合”现象 骨吸收时的形成，反之亦然。它有 据推测，骨质疏松症与年龄相关的改变 由于成骨细胞功能和/或缺陷导致的骨量减少 在“耦合”过程中获得的变化。使用“假定的” 啮齿动物成骨细胞模型，表征 对成骨细胞功能、生长和分化的控制 逐渐被拆解。破骨细胞性骨的控制因素 再吸收作用，如细胞分泌大量的 骨附着部位的氢离子也被识别出来。 一些已发表的观察结果也支持这样的假设 成骨细胞通过以下途径调节破骨细胞的数量和活性 产生短程旁分泌因子；相反，调制 成骨细胞通过破骨细胞活动控制骨形成 还有待详细研究。与我们正在进行的 研究兴趣与年龄相关的骨量变化和 钙转运和我们计划的过去成就 项目努力，本文件中描述的实验方案 应用程序将解决：(1)降钙激素的影响 关于幼年和老年啮齿动物和人类成骨细胞，重点是 细胞内钙调控、钙转运和细胞外营养的调控 细胞生长和中性金属蛋白酶的产生及 蛋白水解酶抑制剂；(2)碱性的关键作用 作为成骨细胞活性指标和调节因子的磷酸酶 (3)两者之间的相互关系。 1，25(OH)2D3及其最新研究进展对细胞分化的调控 发现了细胞内钙稳态的调控；(4) 导致质子放大表达和极化的事件 破骨细胞分化过程中的泵；(5)调节 由于破骨细胞活动而形成的骨形成 强调与年龄相关的“耦合信号”的变化。至 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，各种 带视频的荧光探头和荧光光谱系统 用于细胞内钙和pH定量的图像分析 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.