HORMONAL CONTROL OF CYTOKINES IN BONE AND MARROW CELLS

导致这一应用的工作表明，IL-6基因是 转录调节的两类性类固醇，并发挥作用， 关键作用的性腺功能的骨丢失;雌激素和 雄激素还下调配体结合蛋白的表达， IL-6受体的信号转导成分; 增强破骨细胞前体对IL-6和IL-11的反应性， 并上调成骨细胞发育。 根据这些证据， 提出IL-6和其他细胞因子亚家族成员， gp 130的信号转导，能够刺激 不仅是破骨细胞，也包括成骨细胞的发育。 生产 IL-6，以及IL-6的作用和其他成员的作用， 该细胞因子亚家族受性类固醇的抑制控制。 去除这些抑制作用有助于增加骨 重建和与性腺功能丧失相关的骨质流失。 到 测试这一假设，下调的潜在机制 雌激素和雄激素对基因转录的影响， IL-6，IL-6受体的配体结合亚基（gp 80），和IL-6受体的配体结合亚基（gp 80）。 信号转导亚基（gp 130）将通过鉴定 涉及的顺式作用调控元件及其相应的 转录因子 此外，性类固醇对 将研究可溶性IL-6受体的产生， 在离体鼠骨中表达IL-6、gp 80和gp 130的mRNA 骨髓培养和不脱钙松质骨切片 类固醇充足和性类固醇缺乏的小鼠将使用 原位RT-PCR结合免疫组化。 此外该 细胞因子IL-6亚家族在成骨细胞上调中的作用 性类固醇丧失后骨髓中的祖细胞形成， 以及这些细胞因子和其他生长因子之间的潜在相互作用 将研究成骨细胞生成的因素。 最后，Chimeric 可溶性IL-6或CNTF受体α的构建体，与 识别细胞表面标记的单克隆抗体，将用于 选择性地将相应的细胞因子导向破骨细胞或 成骨细胞祖细胞;并研究这种操作的影响 破骨细胞生成和成骨细胞生成。

Work leading to this application indicates that the IL-6 gene is transcriptionally regulated by both classes of sex steroids and plays a critical role in the bone loss of gonadal function; that estrogens and androgens also downregulate the expression of the ligand-binding and the signal transducing components of the IL-6 receptor; and that their loss enhances the responsiveness of osteoclast precursors to IL-6 and IL-11, and upregulates osteoblast development. Based on this evidence, it is proposed that IL-6, and other members of the cytokine subfamily that share gp130 for the transduction of their signals, are capable of stimulating not only osteoclast, but also osteoblast, development. The production of IL-6, as well as the action of IL-6 and the action of other members of this cytokine subfamily, is under the inhibitory control of sex steroids. Removal of these inhibitory effects contributes to the increased bone remodeling and the bone loss associated with loss of gonadal function. To test this hypothesis, the mechanism(s) underlying the downregulating effects of estrogens and androgens on the transcription of the genes for IL-6, the ligand-binding subunit of the IL-6 receptor (gp80), and the signal transducing subunit (gp130) will be elucidated by identifying the cis-acting regulatory elements involved and their corresponding transcription factors. Further, the effects of sex steroids on the production of the soluble IL-6 receptor will be studied and cells expressing the mRNAs for IL-6, gp80 and gp130 in ex vivo murine bone marrow cultures and undecalcified cancellous bone sections from sex steroid replete and sex steroid deficient mice will be identified, using in situ RT-PCR in combination with immunohistochemistry. In addition, the role of the IL-6 subfamily of cytokines in the upregulation of osteoblast progenitor formation in the bone marrow following loss of sex steroids, and potential interactions between these cytokines and other growth factors on osteoblastogenesis will be investigated. Finally, chimeric constructs of the soluble IL-6 or CNTF receptor alpha, complexed with monoclonal antibodies recognizing cell surface markers, will be used to selectively direct the corresponding cytokines to either osteoclast or osteoblast progenitors; and investigate the effects of such manipulation on osteoclastogenesis and osteoblastogenesis.