Autophagy Protects Advanced Glycation End Product-Induced Apoptosis and Expression of MMP-3 and MMP-13 in Rat Chondrocytes

Abstract

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.

Phenotypic instability of chondrocytes in osteoarthritis: on a path to hypertrophy

“…The transactivation of MMP13 in articular chondrocytes is also subject to epigenetic modulation, as shown by the repression of LEF1‐driven MMP13 gene expression by SIRT1 or the impact of the methylation status of the MMP13 promoter in OA cartilage on its CREB‐ and HIF‐2α‐driven transcriptional activation. Matrix crosslinking and accumulation of AGEs can also drive MMP13 gene expression in chondrocytes, which can be partly reverted by re‐establishing optimal autophagy and proteostasis and therefore reducing AGE‐driven MMP13 expression . Activation of the initially inactive procollagenase represents an additional layer of control, which can occur via changes in temperature or pH, or be caused in a step‐wise manner by other proteases, including plasmin, MT1‐MMP, MMP2, and MMP10 .…”

“…Matrix crosslinking and accumulation of AGEs can also drive MMP13 gene expression in chondrocytes, 88 which can be partly reverted by re-establishing optimal autophagy and proteostasis and therefore reducing AGE-driven MMP13 expression. 191 Activation of the initially inactive procollagenase represents an additional layer of control, which can occur via changes in temperature or pH, or be caused in a step-wise manner by other proteases, including plasmin, MT1-MMP, MMP2, and MMP10. 16 Thus, modulation of the expression of these procollagenase activators may represent an additional level of biological control of collagenase activity and matrix remodeling with potential involvement in OA pathology.…”

Diazoxide ameliorates severity of experimental osteoarthritis by activating autophagy via modulation of the osteoarthritis‐related biomarkers

“…To further investigate whether diazoxide attenuate cartilage degeneration by restoring autophagy by modulating the expression of OA‐related biomarkers, at the cellular level, we examined the expression levels of COL2A1, MMP‐13, TIMP‐1, and ADAMTS5 using quantitative real‐time polymerase chain reaction. Previous studies have reported that autophagy regulates these OA‐related biomarkers . In human articular chondrocytes, the activation of autophagy significantly increases type II collagen expression and proteoglycan synthesis .…”

“…The OA model was generated by transecting the anterior cruciate ligament combined with the resection of the medial menisci in the right knee joint as previously described. 36,37 After washing with sterile saline solution, both skin and capsule were sutured using a 5/0 suture. 100 mg/kg cefazolin sodium was administered intramuscularly at 0, 24, and 48 hours postoperatively.…”

Pioglitazone attenuates advanced glycation end products‐induced apoptosis and calcification by modulating autophagy in tendon‐derived stem cells

“…26 Autophagy plays a key role in cell survival as well as in the regulation of cell apoptosis; numerous studies have demonstrated that promoting autophagy has protective effects against various musculoskeletal diseases such as osteoarthritis and osteoporosis. 28 Yang et al also reported that AGEs increased LC3B, while decreased P62 in osteoblasts. 28 Yang et al also reported that AGEs increased LC3B, while decreased P62 in osteoblasts.…”