PTH REDUCES THE MECHANICAL THRESHOLD IN OSTEOBLASTS

PTH 降低成骨细胞的机械阈值

• 批准号: 6189832
• 负责人: RANDALL L DUNCAN
• 金额: $ 21.67万
• 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/6189832
• 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）：均甲状旁腺激素 （PTH）和机械刺激（MS）已被证明可以刺激净骨 形成，体内。在培养的成骨细胞中对两种刺激的早期反应 是由两者介导的细胞内Ca2+（[Ca2+] i）的迅速增加 细胞外Ca2+进入和细胞内Ca2+释放（ICAR）。在这个 提案，主要研究人员假设PTH降低了机械 通过更改调节的机制，成骨细胞的阈值 [Ca2+] i，从而在MS的更生理水平上促进净骨形成。 PTH和MS激活能够介导的成骨细胞中的许多反应 [Ca2+] i的增长，包括机械敏感的阳离子选择通道 （MSCC），IP3诱导的ICAR和肌动蛋白细胞骨架重排，可以作用 作为这些刺激的收敛部位。在这里，首席调查员 建议检查这些响应对[Ca2+] i的复杂相互作用，以及 它们在成骨细胞中的基因表达和信号扩增中起的作用 响应流体剪切和PTH处理。 在此提案中，主要研究人员将使用细胞生物学， 免疫荧光染色，斑块夹和[Ca2+] I成像技术 检查流体剪切和PTH刺激在[Ca2+] I上的相互作用， 合成代谢标记和旁分泌释放的表达和产生 成骨细胞。他将把这些研究集中在渠道生产和功能上， 与细胞分化和细胞骨架重组有关的ICAR。 该提议的目的是：（1）确定PTH和 在合成代谢标记和旁分泌的表达和产生上的流体剪切 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作为该函数 细胞的分化状态； （3）检查细胞骨架的作用 在受到PTH和流体力的通道的激活和“启动”中。 这些研究旨在提供有关机制的新见解 将生物物理信号转移到成骨细胞功能和方法中 改变此响应。