EARLY RESPONSE PATTERNS IN DIFFERENTIATING OSTEOBLASTS

分化成骨细胞的早期反应模式

• 批准号: 2080976
• 负责人: PHILIP EDWIN KEETING
• 金额: $ 10.22万
• 依托单位: WEST VIRGINIA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-10 至 1997-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2080976
• 关键词: cell differentiation; eicosanoid metabolism; estrogens; human tissue; insulinlike growth factor; interleukin 1; osteoblasts; osteoporosis; parathyroid hormones; transforming growth factors

Because of its high incidence and devastating socio-economic consequences, osteoporosis is an important disorder of the aging population. The disease causes 1.5 million fractures, including 250,000 hip fractures, annually in the United States. Following hip fracture, 50% of the survivors cannot walk independently again and 30-50% require long-term nursing care. The costs of osteoporosis are estimated at $7 to $10 billion annually in the USA. To treat and to prevent this disorder the basic physiological mechanisms regulating bone cell biology must be understood. Eicosanoids (e.g., prostaglandins, leukotrienes, etc.) are key components of a target cell's early responses to various stimulators including growth factors, cytokines, and hormones. While eicosanoid metabolism has been studied in several osteoblastic cell systems and in bone organ cultures, gaps in our knowledge concerning their local production remain. Although eicosanoid production is an early response to stimulation (altered production is evident within minutes) most investigators have measured (only) PGE2 release hours, or days, after treatment. These data may not reflect the dynamic responses of this signal transduction pathway in stimulated osteoblastic cells. Moreover, selecting a priori which eicosanoid to measure increases the probability that major responses in other unexamined members of the eicosanoid family will be missed. This is a critical issue since different eicosanoids often exert opposing biological effects. Presently, even the classes of eicosanoids produced by human osteoblastic cells is unknown. therefore, eicosanoid metabolism will be studied in normal adult human osteoblast-like (hOB) cells derived from trabecular bone explants. The use of hOB cells as the model system for the human osteoblast avoids potential complications introduced in trans-species studies and the abnormal cell responses commonly observed in spontaneous transformants. The hOB cells are partially differentiated and steroid responsive. the impact of 1,25(OH)2D3-induced differentiation on hOB cell eicosanoid metabolism will be examined. Eicosanoid release following treatment with the osteotropic agents estrogen, TGFbeta, PTH, interleukin 1 and IGF-I will be studied and compared in naive and 1,25(OH)2D3-treated hOB cells. These studies will focus on eicosanoid production in short-term incubations (120 minutes or less). Most analyses will initially use HPLC to examine the array of eicosanoids produced by the hOB cells. Follow-up studies will employ specific antisera for quantitative purposes. This work will define the characteristics of hOB cell eicosanoid metabolism, and determine the impact of differentiation on the production of these bioactive lipids. The regulation of hOB cell eicosanoid metabolism by the osteotropic agents will be studied both before and during induced cell differentiation. The molecular mechanism of any differentiation-associated changes in eicosanoid production will be probed at the level of hOB cell phospholipid metabolism. The proposed investigations may influence the design and use of pharmacologic interventions into the progress f osteoporosis and other metabolic bone diseases.

由于其发病率和毁灭性的社会经济后果， 骨质疏松症是衰老人群的重要疾病。 疾病 每年造成150万个骨折，包括250,000个髋部骨折 美国。 髋部骨折后，50％的幸存者无法 再次独立行走，30-50％需要长期护理。 这 骨质疏松症的成本估计为每年7至100亿美元 美国。 治疗和预防这种疾病的基本生理 必须理解调节骨细胞生物学的机制。 类花生酸 （例如，前列腺素，白细胞等）是目标的关键组成部分 细胞对各种刺激剂的早期反应，包括生长因子， 细胞因子和激素。 eicosanoid代谢已在 几个成骨细胞系统和骨骼器官培养物中的缝隙 关于其本地生产的知识仍然存在。 虽然类类 生产是对刺激的早期反应（改变的生产是 明显的几分钟之内）大多数调查人员都测量了（仅）PGE2 释放小时或治疗后几天。 这些数据可能无法反映 该信号转导途径的动态响应刺激 成骨细胞。 此外，选择eicosanoid to的先验 测量增加了其他未经审查的主要响应的可能性 eicosanoid家族的成员将被错过。 这是一个关键问题 由于不同的类固醇通常会发挥相反的生物学作用。 目前，即使是人类成骨细胞产生的类花生酸的类别 细胞是未知的。 因此，将在 源自小梁骨的正常成年成年人类成骨细胞（HOB）细胞 epplants。 将霍布细胞用作人类的模型系统 成骨细胞避免在反式物种中引入潜在的并发症 在自发性中通常观察到的研究和异常细胞反应 转化体。 霍布细胞部分分化和类固醇 响应迅速。 1,25（OH）2d3诱导的分化对HOB细胞的影响 将检查类花生酸代谢。 eicosanoid释放以下 用骨骼剂雌激素，TGFBETA，PTH，白介素治疗1 和IGF-I将在NAIVE和1,25（OH）2d3处理的HOB中进行研究和比较 细胞。 这些研究将重点放在短期内的类类生产上 孵育（120分钟或更短）。 大多数分析最初将使用HPLC 检查霍布细胞产生的一系列eicosanoid。 后续 研究将采用特定的抗血清来定量目的。 这项工作 将定义霍布细胞类eicosanoid代谢的特征，并 确定分化对这些生产的影响 生物活性脂质。 调节霍布细胞类eicosanoid代谢 将在诱导细胞之前和期间研究骨质剂 分化。 任何分化相关的分子机制 eicosanoid产生的变化将在霍布细胞的水平上进行探测 磷脂代谢。 拟议的调查可能会影响 设计和使用药理学干预措施f 骨质疏松症和其他代谢骨疾病。