PTH REDUCES THE MECHANICAL THRESHOLD IN OSTEOBLASTS

PTH 降低成骨细胞的机械阈值

• 批准号: 6381924
• 负责人: RANDALL L DUNCAN
• 金额: $ 22.21万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-15 至 2004-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6381924
• 关键词: 3T3 cells; bone development; calcium channel; calcium indicator; calcium ion; cell differentiation; cytoskeleton; enzyme linked immunosorbent assay; fluid flow; gene expression; hormone regulation /control mechanism; immunofluorescence technique; mechanical pressure; northern blottings; osteoblasts; paracrine; parathyroid hormones; statistics /biometry; voltage /patch clamp; western blottings

DESCRIPTION (Adapted from the Applicant's Abstract): Both parathyroid hormone (PTH) and mechanical stimulation (MS) have been shown to stimulate net bone formation, in vivo. An early response to both stimuli in cultured osteoblasts is a rapid increase in intracellular Ca2+ ([Ca2+]i) that is mediated by both extracellular Ca2+ entry and intracellular Ca2+ release (iCaR). In this proposal, the principal investigator postulates that PTH lowers the mechanical threshold of osteoblasts by altering the mechanisms involved in modulating [Ca2+]i, thereby promoting net bone formation at more physiologic levels of MS. PTH and MS activate a number of responses in osteoblasts capable of mediating this rise in [Ca2+]i, including mechanosensitive, cation-selective channels (MSCC), IP3-induced iCaR and actin cytoskeletal rearrangement, that could act as sites of convergence for these stimuli. Here, the principal investigator proposes to examine the complex interactions of these responses on [Ca2+]i, and the role they play in gene expression and signal amplification in osteoblasts in response to fluid shear and PTH treatment. In this proposal, the principal investigator will use cell biologic, immunofluorescent staining, patch clamp and [Ca2+]i imaging techniques to examine the interaction of fluid shear and PTH stimulation on [Ca2+]i, expression and production of anabolic markers and paracrine release in osteoblasts. He will focus these studies on channel production and function and iCaR in relation to cellular differentiation and cytoskeletal reorganization. The aims of this proposal are to: (1) determine the interaction of PTH and fluid shear on the expression and production of anabolic markers and paracrine factors associated with bone formation and assess the role of the [Ca2+]i increase in these responses; (2) examine the function of MSCC and Ca2+ channels and iCaR in the [Ca2+]i response to fluid shear and PTH as a function of the differentiated state of the cell; and (3) examine the role of the cytoskeleton in activation and "priming" of channels subjected to PTH and fluid forces. These studies are intended to provide new insight into the mechanisms of transduction of the biophysical signal into osteoblastic function and methods to change this response.

描述（改编自申请人的摘要）：甲状旁腺激素 (PTH) 和机械刺激 (MS) 已被证明可以刺激净骨 形成，体内。培养的成骨细胞对两种刺激的早期反应 是细胞内 Ca2+ ([Ca2+]i) 的快速增加，由两者介导 细胞外 Ca2+ 进入和细胞内 Ca2+ 释放 (iCaR)。在这个 提案中，主要研究者假设 PTH 降低了机械强度 通过改变参与调节的机制来调节成骨细胞的阈值 [Ca2+]i，从而在 MS 的生理水平上促进净骨形成。 PTH 和 MS 激活成骨细胞中的许多反应，能够介导 [Ca2+]i 的增加，包括机械敏感、阳离子选择性通道 (MSCC)，IP3 诱导的 iCaR 和肌动蛋白细胞骨架重排，可以发挥作用 作为这些刺激的汇聚点。在这里，首席研究员 建议检查这些反应对 [Ca2+]i 的复杂相互作用，并且 它们在成骨细胞基因表达和信号放大中发挥的作用 响应流体剪切和 PTH 治疗。 在这项提案中，主要研究者将使用细胞生物学、 免疫荧光染色、膜片钳和 [Ca2+]i 成像技术 检查流体剪切和 PTH 刺激对 [Ca2+]i 的相互作用， 合成代谢标记物的表达和产生以及旁分泌释放 成骨细胞。他将把这些研究重点放在渠道的生产和功能上 iCaR 与细胞分化和细胞骨架重组有关。 该提案的目的是：（1）确定 PTH 和 流体剪切对合成代谢标记物和旁分泌的表达和产生的影响 与骨形成相关的因素并评估 [Ca2+]i 的作用 这些反应的增加； (2)检查MSCC和Ca2+通道的功能 [Ca2+]i 对流体剪切和 PTH 的响应中的 iCaR 与 细胞的分化状态； (3) 检查细胞骨架的作用 在受 PTH 和流体力作用的通道的激活和“启动”中。 这些研究旨在提供对机制的新见解 将生物物理信号转变成成骨细胞功能的方法和方法 更改此响应。