Hsp90 mediates insulin-like growth factor 1 and interleukin-1β signaling in an age-dependent manner in equine articular chondrocytes
Hsp90 mediates insulin-like growth factor 1 and interleukin-1β signaling in an age-dependent manner in equine articular chondrocytes
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DOI：
10.1002/art.22664
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发表时间：
2007-07-01
影响因子：
--
通讯作者：
Fortier, Lisa A.
中科院分区：
文献类型：
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作者：
Boehm, Amber K.;Seth, Mayank;Fortier, Lisa A.
目标。软骨细胞中的许多代谢过程被认为有助于细胞外基质中与年龄相关的变化，但Hsp90的已知作用影响了这些代谢过程。Hsp90水平与年龄相关的下降在许多细胞类型中都有记录，并可能导致软骨退化。本研究旨在探讨AGE和Hsp90在软骨细胞胰岛素样生长因子-1(IGF-1)和白介素1-β(IL-1β)信号转导中的作用。用实时定量聚合酶链式反应(PCR)和Western印迹分析分别检测Hsp90信使RNA和蛋白质水平与年龄的关系。用Hsp90抑制剂格尔达那霉素(50 nM、100 nM或500 nM)检测软骨细胞对Hsp90同时刺激IGF-1或IL-1的年龄相关反应。实时定量聚合酶链式反应检测COL2A1和基质金属蛋白酶13(MMP13)基因表达，Western印迹分析检测P42/44和Akt/蛋白激酶B的磷酸化状态。格尔达霉素对Hsp90的抑制作用呈浓度依赖性。100 nM或500 nM格尔达霉素抑制Hsp90可阻断IGF-1诱导的细胞增殖、Akt和p42/44的激活以及COL2A1的表达。基础和IL-1β诱导的MMP13基因表达上调可被所测试的所有浓度的格尔达霉素所阻断。Hsp90功能增益分析显示MMP13mRNAs表达增加。这些结果表明，Hsp90参与了软骨内稳态的相反信号通路，并且分解代谢反应比合成代谢反应对Hsp90抑制更敏感。需要进一步的研究来确定Hsp90抑制在骨关节炎中的作用，以便评估其作为治疗靶点的潜力。
Objective. Many metabolic processes in chondrocytes thought to contribute to age-related changes in the extracellular matrix are influenced by known roles of Hsp90. Age-related decreases in the level of Hsp90 have been documented in numerous cell types and could contribute to cartilage degeneration. The aim of this study was to investigate the roles of age and Hsp90 in insulin-like growth factor 1 (IGF-1) and interleukin-1 beta (IL-1 beta) signaling in chondrocytes.Methods. Levels of Hsp90 messenger RNA (mRNA) and protein, with respect to age, were determined by quantitative real-time polymerase chain reaction (PCR) and Western blot analysis, respectively. The Hsp90 inhibitor geldanamycin (50 nM, 100 nM, or 500 nM) was used to assess age-related responses to Hsp90 with concurrent IGF-1 or IL-1 beta stimulation of chondrocytes. Quantitative real-time PCR was used to measure COL2A1 and matrix metalloproteinase 13 (MMP13) gene expression; Western blot analysis was performed to determine the phosphorylation status of p42/44 and Akt/protein kinase B.Results. The effects of Hsp90 inhibition with geldanamycin were concentration dependent. Inhibition of Hsp90 with 100 nM or 500 nM geldanamycin blocked IGF-1-induced cell proliferation, Akt and p42/44 activation, and COL2A1 expression. Basal and IL-1 beta-induced up-regulation of MMP13 mRNA was blocked by all concentrations of geldanamycin tested. Gain-of-function assays with Hsp90 resulted in increased expression of MMP13 mRNA.Conclusion. These results suggest that Hsp90 is involved in opposing signaling pathways of cartilage homeostasis, and that catabolic responses are more sensitive to Hsp90 inhibition than are anabolic responses. Further studies are needed to determine the role of Hsp90 inhibition in osteoarthritis in order to assess its potential as a therapeutic target.