IN VIVO MECHANICAL LOADING EARLY RESPONSE GENES

体内机械加载早期反应基因

• 批准号: 2406210
• 负责人: DIANE M CULLEN
• 金额: $ 18.65万
• 依托单位: CREIGHTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-05 至 2001-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2406210
• 关键词: biological signal transduction; bone density; bone development; genetic library; indomethacin; inhibitor /antagonist; laboratory rat; mature animal; mechanical pressure; messenger RNA; molecular cloning; nitric oxide; northern blottings; nucleic acid hybridization; nucleic acid sequence; osteoporosis; parathyroid hormones; polymerase chain reaction; regulatory gene; statistics /biometry

DESCRIPTION (Adapted from the Applicant's Abstract): Osteoporosis is a major health problem due, in part, to low bone mass. The fundamental goal of the applicants' research is to find mechanisms for increasing bone mass in the adult skeleton. The purpose of this project is to identify early response genes for mechanically-induced bone formation and examine the association of these genes with first messengers, such as prostaglandins and nitric oxide. This project will use an in vivo model of controlled external loading. The hypotheses to be tested are: (1) in vivo loading changes mRNA levels of up to 7 early response genes that are indomethacin-sensitive and bone-specific; (2) these gene responses are first detectable at 30 minutes after the initial load, and indomethacin prevents the response for up to 8 hours while blocking bone adaptation to repeated loading; (3) nitric oxide is a biochemical messenger of mechanical loading and stimulates the same bone-specific early response genes that indomethacin suppresses; and (4) indomethacin-sensitive, early response genes for loading are not stimulated by other bone-forming agents, such as parathyroid hormone and growth hormone. The Specific Aims are: (1) to identify, by ddPCR, a subset of periosteal genes, with mRNA levels elevated or suppressed 30 minutes after loading, that are sensitive to indomethacin and specific to loaded bone; (2) to determine indomethacin effects on the time course (0.25-8.0 hrs) of mRNA levels of these genes by Northern blots and associate the differences with histomorphometric measurements at 3 weeks of loading; (3) to compare differences in loading response for these genes, between indomethacin and L-NG-monomethyl-arginine (L-NMMA) treatment at 30 minutes, 2 hours, and 3 weeks; and (4) to compare differences in gene response to loading, parathyroid hormone or growth hormone treatment at 30 minutes, 2 hours and 3 weeks. It is suggested that the results from these studies will identify indomethacin-sensitive loading early response genes and characterize their time course, association with first messengers, and association with other bone-forming agents. This knowledge, from an in vivo model, is intended to contribute to the knowledge gained from in vitro studies, aid in the discovery of bone-specific signal pathways for mechanical stimulation, and may help in the design of treatments to increase bone response to mechanical loading and increase bone mass.

描述（改编自申请人的摘要）：骨质疏松症是一种 主要的健康问题部分是由于骨量低造成的。 根本目标 申请人的研究重点是寻找增加骨量的机制 在成人的骨骼中。 该项目的目的是尽早确定 机械诱导骨形成的反应基因并检查 这些基因与第一信使的关联，例如前列腺素和 一氧化氮。 该项目将使用受控外部的体内模型 加载中。 待检验的假设是：（1）体内mRNA负荷变化 多达 7 个对吲哚美辛敏感的早期反应基因的水平 骨骼特异性； (2) 这些基因反应在 30 分钟时首次被检测到 初始负荷后，吲哚美辛可阻止反应长达 8 数小时，同时阻碍骨骼适应重复负载； (3)一氧化氮 是机械负荷的生化信使并刺激相同的 吲哚美辛抑制的骨特异性早期反应基因；和（4） 吲哚美辛敏感的加载早期反应基因不会受到刺激 通过其他成骨剂，例如甲状旁腺激素和生长 激素。 具体目标是： (1) 通过 ddPCR 鉴定 骨膜基因，30分钟后mRNA水平升高或抑制 负载，对吲哚美辛敏感并且对负载的骨具有特异性； (2) 确定吲哚美辛对 mRNA 时程（0.25-8.0 小时）的影响 通过 Northern blot 检测这些基因的水平，并将差异与 加载 3 周时进行组织形态测量； (3)比较 吲哚美辛和这些基因的负载反应存在差异 L-NG-单甲基精氨酸 (L-NMMA) 处理 30 分钟、2 小时和 3 小时 几周； (4) 比较基因对负荷反应的差异， 甲状旁腺激素或生长激素治疗 30 分钟、2 小时和 3 几周。 建议这些研究的结果将确定 吲哚美辛敏感加载早期反应基因并表征其 时间进程、与第一使者的联系以及与其他使者的联系 成骨剂。 这些来自体内模型的知识旨在 有助于从体外研究中获得的知识，帮助 发现机械刺激的骨特异性信号通路，以及 可能有助于设计治疗方法以增加骨骼对机械的反应 负荷并增加骨量。