Role of autophagy in the progression of osteoarthritis: The autophagy inhibitor, 3-methyladenine, aggravates the severity of experimental osteoarthritis.
Accumulating evidence suggests that autophagy is closely related to the pathogenesis of osteoarthritis (OA). The aim of this study was to determine the changes in autophagy during the progression of OA and to elucidate the specific role of autophagy in OA. For this purpose, a cellular model of OA was generated by stimulating SW1353 cells with interleukin (IL)-1β and a rabbit model of OA was also established by an intra-articular injection of collagenase, followed by treatment with the autophagy specific inhibitor, 3-methyladenine (3-MA). Cell viability was analyzed by MTS assay, and the mRNA expression levels of matrix metalloproteinases (MMP)-13 and tissue inhibitor of metalloproteinase (TIMP)-1 were determined by RT-qPCR. Cartilage degeneration was examined under a light microscope, and autophagosome and chondrocyte degeneration was observed by transmission electron microscopy. The protein expression of Beclin-1 and light chain 3 (LC3)B was evaluated by western blot analysis and immunofluorescence staining. We found that the autophagy was enhanced during the early stages and was weakened during the late stages of experimental OA. The inhibition of autophagy by 3-MA significantly aggravated the degeneration of chondrocytes and cartilage in experimental OA. Our results thus determine the changes in autophagy during different stages of OA, as well as the role of impaired autophagy in the development of OA. Our data suggest that the regulation of autophagy may be a potential therapeutic strategy with which to attenuate OA.
Department of Orthopaedics, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P.R. China.
Ni-Tao
NT
Cheng
Department of Orthopaedics, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P.R. China.
Hai
H
Meng
Department of Orthopaedics, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P.R. China.
Li-Feng
LF
Ma
Department of Orthopaedics, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P.R. China.
Liang
L
Zhang
Department of Orthopaedics, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P.R. China.
Hao-Miao
HM
Yu
Department of Orthopaedics, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P.R. China.
Zhen-Zhong
ZZ
Wang
Department of Orthopaedics, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P.R. China.
Ai
A
Guo
D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001343:Autophagy / Q000187:drug effects; D000071186:Beclin-1 / Q000378:metabolism; D015415:Biomarkers; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004195:Disease Models, Animal; D018450:Disease Progression; D015870:Gene Expression; D006801:Humans; D053583:Interleukin-1beta / Q000378:metabolism / Q000494:pharmacology; D008297:Male; D053509:Matrix Metalloproteinase 13 / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D010003:Osteoarthritis / Q000209:etiology* / Q000378:metabolism* / Q000473:pathology; D011817:Rabbits; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism
D000071186:Beclin-1; D015415:Biomarkers; D053583:Interleukin-1beta; C502070:MAP1LC3B protein, human; D008869:Microtubule-Associated Proteins; D019715:Tissue Inhibitor of Metalloproteinase-1; C025946:3-methyladenine; D053509:Matrix Metalloproteinase 13; D000225:Adenine