Overexpression of aquaporin 4 in articular chondrocytes exacerbates the severity of adjuvant-induced arthritis in rats: an in vivo and in vitro study.
Overexpression of aquaporin 4 in articular chondrocytes exacerbates the severity of adjuvant-induced arthritis in rats: an in vivo and in vitro study.
复制标题
关节软骨细胞中水通道蛋白 4 的过度表达加剧了大鼠佐剂诱导的关节炎的严重程度：一项体内和体外研究
DOI：
10.1186/s12950-017-0153-8
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Li CM
中科院分区：
文献类型：
--
作者：
Cai L;Lei C;Li R;Chen WN;Hu CM;Chen XY;Li CM
关节软骨细胞功能障碍是类风湿关节炎（RA）发病的关键步骤，其分子机制尚不完全清楚。本研究旨在探讨水通道蛋白4 （aquaporin 4, AQP4）在佐剂性关节炎（AIA）大鼠关节软骨细胞中的表达及其在关节炎发生中的作用。方法30只大鼠分为正常组和AIA组（n = 15）。采用皮内注射完全弗氏佐剂诱导大鼠AIA，通过继发性足跖肿胀和膝关节损伤组织学评估。免疫组织化学和western blot检测AQP4在关节软骨中的定位和蛋白表达。体外培养AIA关节软骨细胞，并用乙酰唑胺（一种AQPs抑制剂）处理。western blot法、MTT法和real-time PCR法分别检测AQP4蛋白水平、ii型胶原（COII）和聚集蛋白的细胞增殖和mRNA水平。结果免疫组化和western blot结果显示，AIA大鼠软骨组织中AQP4蛋白表达水平高于正常大鼠。相关分析显示，AIA大鼠软骨组织AQP4蛋白水平与AIA诱导后第26天继发足肿胀及关节损伤病理评分呈显著正相关。此外，乙酰唑胺治疗可有效降低AQP4蛋白水平，增加细胞增殖和COII和aggrecan mRNA水平，提示乙酰唑胺抑制AQP4可使体外AIA关节软骨细胞功能障碍正常化。结论sour数据提供了一定的实验证据，表明AQP4在关节软骨细胞中的过表达加重了AIA的严重程度，可能是治疗RA的新靶点。
BackgroundThe dysfunction of articular chondrocytes is a crucial step in rheumatoid arthritis (RA) pathogenesis while its molecular mechanisms are not fully known. This study was aimed to investigate the expression of aquaporin 4 (AQP4) in articular chondrocytes of adjuvant-induced arthritis (AIA) rats and its involvement in AIA development.MethodsThirty rats were divided into normal and AIA group (n = 15). Rat AIA was induced by intradermal injection of complete Freund’s adjuvant and evaluated by secondary paw swelling and histological assessments on knee joint damage. Localization and protein expression of AQP4 in articular cartilage were examined by immunohistochemistry and western blot. In vitro study, AIA articular chondrocytes were cultured and treated with acetazolamide, an AQPs inhibitor. AQP4 protein level, cell proliferation and mRNA levels of type-II collagen (COII) and aggrecan were measured by western blot, MTT assay and real-time PCR, respectively.ResultsThe results of immunohistochemistry and western blot indicated that AQP4 showed higher protein levels in cartilage tissues of AIA rats than that of normal rats. Correlation analysis revealed that AQP4 protein level in cartilage tissues of AIA rats remarkably correlated positively with secondary paw swelling on day 26 after AIA induction as well as pathological scores on joint damage. Additionally, acetazolamide treatment effectively decreased AQP4 protein level, increased cell proliferation and mRNA levels of COII and aggrecan, suggesting AQP4 inhibition by acetazolamide could normalize the dysfunction of AIA articular chondrocytes in vitro.ConclusionsOur data provide certain experimental evidence that AQP4 over-expression in articular chondrocytes aggravated AIA severity and might be a novel target for RA treatment.