Xiang Chen 1,2 , Wang Gong 1,2 , Xiaoyan Shao 1,2 , Tianshu Shi 1,2 , Lei Zhang 1,2 , Jian Dong 1,2 , Yong Shi 1,2 , Siyu Shen 1,2 , Jianghui Qin 1,2,3 , Qing Jiang 4,2,3 , Baosheng Guo 4,2,3 Show Affiliations »
Abstract
OBJECTIVE: The aim of the study was to investigate the role and regulatory mechanisms of fibroblast-like synoviocytes (FLSs) and their senescence in the progression of osteoarthritis (OA). METHODS: Synovial tissues from normal patients and patients with OA were collected. Synovium FLS senescence was analysed by immunofluorescence and western blotting. The role of methyltransferase-like 3 (METTL3) in autophagy regulation was explored using N6-methyladenosine (m6A)-methylated RNA and RNA immunoprecipitation assays. Mice subjected to destabilisation of the medial meniscus (DMM) surgery were intra-articularly injected with or without pAAV9 loaded with small interfering RNA (siRNA) targeting METTL3. Histological analysis was performed to determine cartilage damage. RESULTS: Senescent FLSs were markedly increased with the progression of OA in patients and mouse models. We determined that impaired autophagy occurred in OA-FLS, resulting in the upregulation of senescence-associated secretory phenotype (SASP). Re-establishment of autophagy reversed the senescent phenotype by suppressing GATA4. Further, we observed for the first time that excessive m6A modification negatively regulated autophagy in OA-FLS. Mechanistically, METTL3-mediated m6A modification decreased the expression of autophagy-related 7, an E-1 enzyme crucial for the formation of autophagosomes, by attenuating its RNA stability. Silencing METTL3 enhanced autophagic flux and inhibited SASP expression in OA-FLS. Intra-articular injection of synovium-targeted METTL3 siRNA suppressed cellular senescence propagation in joints and ameliorated DMM-induced cartilage destruction. CONCLUSIONS: Our study revealed the important role of FLS senescence in OA progression. Targeted METTL3 inhibition could alleviate the senescence of FLS and limit OA development in experimental animal models, providing a potential strategy for OA therapy. © Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.
OBJECTIVE: The aim of the study was to investigate the role and regulatory mechanisms of fibroblast-like synoviocytes (FLSs) and their senescence in the progression of osteoarthritis (OA). METHODS: Synovial tissues from normal patients and patients with OA were collected. Synovium FLS senescence was analysed by immunofluorescence and western blotting. The role of methyltransferase-like 3 (METTL3) in autophagy regulation was explored using N6-methyladenosine (m6A)-methylated RNA and RNA immunoprecipitation assays. Mice subjected to destabilisation of the medial meniscus (DMM) surgery were intra-articularly injected with or without pAAV9 loaded with small interfering RNA (siRNA) targeting METTL3. Histological analysis was performed to determine cartilage damage. RESULTS: Senescent FLSs were markedly increased with the progression of OA in patients and mouse models. We determined that impaired autophagy occurred in OA-FLS, resulting in the upregulation of senescence-associated secretory phenotype (SASP). Re-establishment of autophagy reversed the senescent phenotype by suppressing GATA4. Further, we observed for the first time that excessive m6A modification negatively regulated autophagy in OA-FLS. Mechanistically, METTL3-mediated m6A modification decreased the expression of autophagy-related 7, an E-1 enzyme crucial for the formation of autophagosomes, by attenuating its RNA stability. Silencing METTL3 enhanced autophagic flux and inhibited SASP expression in OA-FLS. Intra-articular injection of synovium-targeted METTL3 siRNA suppressed cellular senescence propagation in joints and ameliorated DMM-induced cartilage destruction. CONCLUSIONS: Our study revealed the important role of FLS senescence in OA progression. Targeted METTL3 inhibition could alleviate the senescence of FLS and limit OA development in experimental animal models, providing a potential strategy for OA therapy. © Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.
Entities: Chemical
Keywords:
biological therapy; fibroblasts; inflammation; knee; osteoarthritis
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Year: 2021
PMID： 34706873 DOI： 10.1136/annrheumdis-2021-221091
Source DB: PubMed Journal: Ann Rheum Dis ISSN： 0003-4967 Impact factor: 19.103