TMF通过调控Sirt1/STAT3信号通路抑制 骨关节炎软骨胞外基质降解

TMF inhibits extracellular matrix degradation in osteoarthritis cartilage by regulating the Sirt1/STAT3 signaling pathway

摘要

目的 骨关节炎（Osteoarthritis， OA）是一种以胞外基质（Extracellular matrix， ECM）降解、软骨细胞凋亡及慢性炎症为特征的退行性关节疾病。软骨破坏及ECM降解是造成关节功能丧失和残疾的重要因素。信号转导和转录激活因子3（Signal transduction and activator of transcription 3， STAT3）可上调MMP-13的表达，而后者可降解Ⅱ型胶原蛋白。前期研究表明，5，7，3'，4'-四甲氧基黄酮（5，7，3'，4'-tetramethoxyflavone， TMF）对软骨细胞具有保护性。本研究旨在探讨TMF通过调控Sirt1/STAT3信号通路而抑制ECM降解。 方法 通过关节腔注射碘乙酸钠构建大鼠OA模型，HE染色和免疫组织化学分析研究软骨病理变化。采用IL-1β刺激C28/I2细胞建立OA样软骨细胞模型。利用Western blot检测蛋白质表达。 结果 在大鼠OA模型中，MMP-13表达上调，而Ⅱ型胶原蛋白表达是下调。STAT3的磷酸化水平提高。TMF可逆转STAT3调控的MMP-13和v型胶原蛋白的表达。活化STAT3或抑制Sirt1功能可减弱TMF对ECM降解的抑制作用。 结论 OA细胞和动物模型表明，TMF通过激活Sirt1表达而抑制STAT3信号通路介导的ECM降解。

Abstract

Objective Osteoarthritis （OA） is a degenerative joint disease characterized by extracellular matrix （ECM） degradation， chondrocyte apoptosis， and chronic inflammation. Cartilage destruction and ECM degeneration contribute to joint function loss and disability. Signal transducer and activator of transcription 3 （STAT3） up-regulates the expression of MMP-13， which degrades collagen Ⅱ. Our previous study found that 5，7，3'，4'-tetramethoxyflavone （TMF） exhibited protective effects on OA chondrocytes. This study aims to investigate the protective role of TMF in inhibiting ECM degradation by mediating the Sirt1/STAT3 signaling pathway. Methods Rat OA models were established by the injection of monosodium iodoacetate （MIA）. Hematoxylin & eosin （HE） staining and immunohistochemistry （IHC） analysis were performed. IL-1β stimulated C28/I2 cells were used as OA-like chondrocyte cell model. Western blotting assays were used to determine the protein expression. Results The expression of MMP-13 was upregulated while type Ⅱ collagen expression is downregulated， and the phosphorylation level of STAT3 is increased in rat OA models. TMF reverses the STAT3-mediated expression of MMP-13 and type v collagen. Activation of STAT3 or inhibition of Sirt1 function attenuates the inhibitory effect of TMF on ECM degradation. Conclusion TMF can inhibit ECM degradation mediated by the STAT3 signal pathway by activating Sirt1 expression in OA cell and animal models.

关键词

骨关节炎 / 胞外基质降解 / 软骨细胞 / 5，7，3'，4'-四甲氧基黄酮 / 信号转导及转录激活因子

Key words

Osteoarthritis / Extracellular matrix degradation / Chondrocytes / 5，7，3'，4'-tetramethoxyflavone / Signal transduction and activator of transcription

基金资助

Project Supported by Jiangxi Provincial Natural Science Foundation(20212ACB206002)