OSTEOCLAST MEDIATED BONE REMODELING

骨骼的发育和重塑依赖于复杂的相互作用 由骨髓细胞、骨髓产生的体液和局部因子网络 细胞、免疫活性细胞、血管细胞和这些细胞的前体 细胞群。关于哪些成骨细胞因子 影响破骨细胞(Oc)的发育以及它们如何帮助定义 细胞和分子过程参与骨发育和 重塑并提供潜在的新治疗策略来克服 骨形成和吸收中的内分泌或局部障碍成为 不耦合。到目前为止，这种研究途径的反面已经收到了 只是有限的关注，即OCS可能如何调节成骨细胞 发育、活动和衰老。现在越来越多的人意识到 基于实验证据表明，OCS合成和 释放细胞因子、生长因子、基质分子、花生四烯酸 代谢物，以及其他活性物质，如超氧化物和一氧化氮 氧化物。这些都可能影响成骨细胞的分化和作用。这个 此项目中列出的目标旨在建立在我们的 OCS和Oc样细胞对成骨细胞的调节作用观察 发展和活动。在上一次支持期间，我们展示了 OCS产生小的促炎肽，称为趋化因子，如 IL-8和GROAlpha以一种受调控的方式，这些趋化因子 影响成骨细胞的发育和功能。为了进一步定义角色 Oc来源的趋化因子在正常和病理性骨重建中的表达 建议：1)扩大我们对OCS提出的趋化因子及其 激素细胞因子和基质依赖信号的调节，2) 检查Oc衍生的趋化因子，如IL-8和GROAlpha的影响， 对成骨细胞发育和功能的影响 成骨细胞迁移、整合素表达、基质合成或 降解；3)鉴定和鉴定成骨细胞趋化因子 受体具有成骨细胞发育、生理和 病理生理学。近年来Oc参与的信号转导机制-- 衍生趋化因子对成骨细胞生成和活性的调节 将会被检查。上述所有研究都将结合使用 体内和体外方法以及包括大鼠在内的模型系统 用于组织形态计量学研究的颅骨注射模型，人体组织 切片进行原位杂交和免疫组织化学分析， 分离人和禽类OCS人Oc样细胞、小鼠Oc样细胞 发育和从IL-8受体基因敲除小鼠获得的细胞。法团 趋化因子的产生、mRNA的稳定水平及其调控 通过RT=聚合酶链式反应、核糖核酸酶保护试验、趋化因子酶联免疫吸附试验和原位检测进行评估 杂交技术。成骨细胞的发育和活性将 基于多个生化和分子标记的评估 成骨细胞表型，包括整合素、基质蛋白和 金属蛋白酶。这类研究预计将揭示出 正常的骨重建机制，并有可能提供洞察 骨骼病理，如骨质疏松症、骨关节炎等 炎症性骨病。

Bone development and remodeling are dependent on a complex interactive network of humoral and local factors produced by bone cells, bone marrow cells, immunocompetent cells, vascular cells, and precursors for these cell populations. Insights obtained as to which osteoblast factors influence osteoclast (Oc) development and how they have helped define the cellular and molecular processes involved in bone development and remodeling and provide potential new therapeutic strategies to overcome endocrine or local disorders in bone formation and resorption becomes uncoupled. The converse of this avenue of research has to date received only limited attention, namely, how Ocs might regulate osteoblast development, activity, and senescence. There is now a growing awareness based on experimental evidence demonstrating that Ocs synthesize and release cytokines, growth factors, matrix molecules, arachidonic acid metabolites, and other reactive species such as superoxide and nitric oxide. These may influence osteoblast differentiation and action. The objectives outlined in this project re designed to build on our observations that Ocs and Oc-like cells can modulate osteoblast development and activity. During the last period of support we showed that Ocs produce small pro-inflammatory peptides know as chemokines, such as IL-8 and GROalpha, in a regulated fashion and that these chemokines influenced osteoblast development and function. To further define the role of Oc-derived chemokines in normal and pathological bone remodeling we propose: 1) to expand our analysis of chemokines proposed by Ocs and their modulation by hormonal cytokine and matrix-dependent signals, 2) to examine the effects of Oc-derived chemokines, such as IL-8 and GROalpha, on osteoblast development and function, including their influence on osteoblast migration, integrin expression, matrix synthesis or degradation, and 3) to identify and characterize osteoblast chemokine receptors has a function of osteoblast development, physiology, and pathophysiology. Recent signal transduction mechanisms involved in Oc- derived chemokine mediated modulation of osteoblastogenesis and activity will be examined. All of the above studies will use a combination of in vivo and in vitro approaches, and model systems including the rat calvarial injection model for histomorphometric studies, human tissue sections for in situ hybridization and immunohistochemical analysis, isolated human and avian Ocs human Oc-like cells, the mouse Oc-like cell developmental, and cells obtained from an IL-8 receptor knockout mouse. Oc chemokine production, mRNA steady state levels and regulation will be assessed by RT=PCR, RNAse protection assay, chemokine ELISA, and in situ hybridization techniques. Osteoblast development and activity will be evaluated based on multiple biochemical and molecular markers of the osteoblast phenotype, including integrins, matrix proteins, and metalloproteinases. Such studies are anticipated to reveal new aspects of normal bone remodeling mechanisms and have potential to lend insight into skeletal pathologies such as osteoporosis, osteoarthritis and other inflammatory bone disorders.