Huang Wenzhou, Ao Peng, Li Jian, Wu Tianlong, Xu Libiao, Deng Zhongbo, Chen Wenjie, Yin Changchang, Cheng Xigao
Department of Orthopaedic Surgery, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China.
Jiujiang University, Key Laboratory of Medical Transformation of Jiujiang, Jiujiang, Jiangxi 332000, China.
Biomed Res Int. 2017;2017:6341919. doi: 10.1155/2017/6341919. Epub 2017 Feb 7.
Aging is one of the most prominent risk factors for the pathological progression of osteoarthritis (OA). One feature of age-related changes in OA is advanced glycation end products (AGEs) accumulation in articular cartilage. Autophagy plays a cellular housekeeping role by removing dysfunctional cellular organelles and proteins. However, the relationship between autophagy and AGE-associated OA is unknown. The aim of this study is to determine whether autophagy participates in the pathology of AGE-treated chondrocytes and to investigate the exact role of autophagy in AGE-induced cell apoptosis and expression of matrix metalloproteinase- (MMP-) 3 and MMP-13. AGEs induced notable apoptosis that was detected by Annexin V/PI double-staining, and the upregulation of MMP-3 and MMP-13 was confirmed by Western blotting. Autophagy-related proteins were also determined by Western blotting, and chondrocytes were transfected with mCherry-GFP-LC3B-adenovirus to monitor autophagic flux. As a result, autophagy significantly increased in chondrocytes and peaked at 6 h. Furthermore, rapamycin (RA) attenuated AGE-induced apoptosis and expression of MMP-3 and MMP-13 by autophagy activation. In contrast, pretreatment with autophagy inhibitor 3-methyladenine (3-MA) enhanced the abovementioned effects of AGEs. We therefore demonstrated that autophagy is linked with AGE-related pathology in rat chondrocytes and plays a protective role in AGE-induced apoptosis and expression of MMP-3 and MMP-13.
衰老为骨关节炎（OA）病理进展的最显著风险因素之一。OA中与年龄相关变化的一个特征是晚期糖基化终末产物（AGEs）在关节软骨中的积累。自噬通过清除功能失调的细胞器和蛋白质发挥细胞清理作用。然而，自噬与AGE相关OA之间的关系尚不清楚。本研究的目的是确定自噬是否参与AGE处理的软骨细胞的病理过程，并研究自噬在AGE诱导的细胞凋亡以及基质金属蛋白酶（MMP）-3和MMP-13表达中的具体作用。通过Annexin V/PI双染检测到AGEs诱导显著的细胞凋亡，并且通过蛋白质免疫印迹法证实了MMP-3和MMP-13的上调。还通过蛋白质免疫印迹法测定自噬相关蛋白，并用mCherry-GFP-LC3B-腺病毒转染软骨细胞以监测自噬通量。结果，软骨细胞中的自噬显著增加并在6小时达到峰值。此外，雷帕霉素（RA）通过激活自噬减轻了AGE诱导的细胞凋亡以及MMP-3和MMP-13的表达。相反，用自噬抑制剂3-甲基腺嘌呤（3-MA）预处理增强了AGEs的上述作用。因此，我们证明自噬与大鼠软骨细胞中AGE相关的病理过程相关，并在AGE诱导的细胞凋亡以及MMP-3和MMP-13的表达中发挥保护作用。
