Transcriptional induction of connective tissue growth factor/hypertrophic chondrocyte-specific 24 gene by dexamethasone in human chondrocytic cells
Transcriptional induction of connective tissue growth factor/hypertrophic chondrocyte-specific 24 gene by dexamethasone in human chondrocytic cells
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DOI：
10.1016/s8756-3282(03)00227-8
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发表时间：
2003-10-01
期刊：
影响因子：
4.1
通讯作者：
Takigawa, M
中科院分区：
文献类型：
--
作者：
Kubota, S;Moritani, NH;Takigawa, M
结缔组织生长因子（CTGF/Hcs24）是软骨细胞生长分化的关键生长因子。在本报告中，我们首次描述了糖皮质激素在软骨细胞系HCS-2/8中介导的CTGF/Hcs24基因的诱导。Northern blotting和实时定量聚合酶链反应（PCR）证实，50 nM地塞米松治疗后，CTGF/Hcs24的稳态mRNA水平显著升高。与mRNA的增加相对应，CTGF/Hcs24蛋白的产生显著增强，在长达6小时的时间过程中。mRNA的增加可归因于转录增强，因为相同浓度的地塞米松不影响CTGF/Hcs24 mRNA的稳定性，mRNA降解实验结果表明。然而，出乎意料的是，原型ctgf/hcs24启动子并不负责地塞米松刺激，这表明糖皮质激素受体结合位点可能在ctgf/hcs24基因的其他位置。在小鼠成纤维细胞中观察到地塞米松对原型启动子活性的增强，表明ctgf/hcs24基因表达调控机制的复杂性。重要的是，相同浓度的地塞米松显著刺激HCS-2/8细胞的蛋白多糖合成，其水平与外源添加CTGF/Hcs24相同。这些发现表明糖皮质激素对软骨细胞生成CTGF/Hcs24有新的影响，并提示CTGF/Hcs24可能介导地塞米松对软骨细胞表型的刺激作用。此外，我们的研究结果揭示了糖皮质激素诱导CTGF/Hcs24的复杂机制。(C) 2003 Elsevier Inc.版权所有。
Connective tissue growth factor (CTGF/Hcs24) is a critical growth factor for chondrocytic growth and differentiation. In this report, we describe for the first time glucocorticoid-mediated induction of the CTGF/Hcs24 gene in a chondrocytic cell line, HCS-2/8. Steady-state mRNA levels of CTGF/Hcs24 were remarkably increased after treatment with 50 nM dexamethasone, as confirmed by Northern blotting and quantitative real-time polymerase chain reaction (PCR) analysis. Corresponding to the increase in mRNA, production of CTGF/Hcs24 protein was remarkably enhanced, following a time course of up to 6 h. The observed increase in mRNA can be ascribed to transcriptional enhancement, since the stability of CTGF/Hcs24 mRNA was not affected by the same concentration of dexamethasone, which was indicated by the results of an mRNA degradation assay. However, unexpectedly, the prototypic ctgf/hcs24 promoter was not responsible for the dexamethasone stimulation, suggesting the glucocorticoid receptor binding site(s) to be elsewhere in the CTGF/Hcs24 gene. Enhancement of the prototypic promoter activity by dexamethasone was observed in murine fibroblastic cells, demonstrating the complexity of the regulatory mechanism of ctgf/hcs24 gene expression. Of importance, dexamethasone at the same concentration significantly stimulated proteoglycan synthesis in HCS-2/8 cells up to the same levels as exogenously added CTGF/Hcs24. These findings represent a novel effect of glucocorticoid on the production of CTGF/Hcs24 by chondrocytic cells, and indicate that CTGF/Hcs24 may mediate the stimulative effect of dexamethasone on chondrocytic phenotypes. Also, our results shed light on the complex mechanism of CTGF/Hcs24 induction by glucocorticoids. (C) 2003 Elsevier Inc. All rights reserved.