SIRT1过表达可抑制衣霉素诱导软骨细胞内质网应激

SIRT1 overexpression inhibits tunicamycin-induced endoplasmic reticulum stress in chondrocytes

目的探究SIRT1对衣霉素诱导的软骨细胞内质网应激的影响。方法分离人正常软骨细胞和骨关节炎(OA)软骨细胞,观察细胞形态,免疫细胞化学染色检测Ⅱ型胶原表达,Western blot检测SIRT1表达。将培养的软骨细胞分为对照组(OA软骨细胞、正常软骨细胞)、正常软骨细胞组(衣霉素组、SIRT1过表达组和衣霉素+SIRT1过表达组)。24 h后,Western blot检测ERS相关蛋白(CHOP、p-e IF2α和ATF4等)、凋亡相关蛋白(Bcl-2、Bax和caspase-3等)以及p-P38的表达。ELISA检测NF-κB活性。结果与人正常软骨细胞相比,OA软骨细胞增殖缓慢,Ⅱ型胶原和SIRT1表达均显著降低(P<0.05)。与正常软骨细胞对照组相比,OA对照组和0.5 mg/L衣霉素组CHOP、p-e IF2α、ATF4和p-P38表达上调,NF-κB活性增加,Bcl-2表达明显下调,Bax和caspase-3表达明显增加(P<0.05)。SIRT1过表达处理则显著逆转上述蛋白表达。结论 SIRT1过表达可抑制衣霉素诱导的软骨细胞内质网应激和细胞凋亡,并下调P38/NF-κB活化。

Objective To explore the effect of silent mating type information regulation 2 homolog 1（ SIRT1） on tunicamycin-induced endoplasmic reticulum stress（ ERS） in chondrocytes. Methods After isolation of human normal chondrocytes and osteoarthritis（ OA） chondrocytes,morphological identification was performed,collagen typeⅡ expression was determined by immunohistochemical staining and SIRT1 expression was detected by Western blot. Cultured chondrocytes were divided into five groups： control group（ OA chondrocytes,normal chondrocytes）,normal chondrocytes group（ Tuni,SIRT1 overexpression,and Tuni ＋ SIRT1 overexpression）. After 24 h treatment,the expression of ERS-related proteins of C / EBP homologous protein（ CHOP）,eukaryotic initiation factor-2 α（ e IF2α） phosphorylation,and activating transcription factor 4（ ATF4）,and the expression of apoptosisrelated proteins of Bcl-2,Bax,and caspase-3,as well as p-P38 protein were determined by Western blot. NF-κB activity was determined by ELISA. Results Compared to human normal chondrocytes,both the cell proliferation and the expression of collagen type Ⅱ and SIRT1 in OA chondrocytes were markedly reduced（ P〈0. 05）. OA control group and 0. 5 mg / L tunicamycin treatment consistently resulted in ERS and cell apoptosis with concomitantenhancement of CHOP,p-e IF2 α and ATF4 proteins,increases of NF-κB activity and p-P38,Bax,caspase-3proteins,and reduction of Bcl-2（ P〈0. 05）. However,SIRT1 overexpression may reverse these effects.Conclusions SIRT1 overexpression inhibits tunicamycin-induced ERS and cell apoptosis,and further attenuates P38 / NF-κB activation in chondrocytes.