Work

ALKBH5 Regulates Apoptosis of Rheumatoid Arthritis Fibroblast-like Synoviocytes by Modulating miR-181b-5p Maturation via m6A Demethylation

Year: 2025

Type: article

Abstract: IntroductionRheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by synovial inflammation, joint destruction, and a range of systemic complications.The pathogenesis of RA is multifactorial, involving genetic, epigenetic, and environmental components 2 .Clinically, patients often present with morning stiffness, joint swelling, and pain 3 .If left untreated, RA can result in irreversible joint deformities, functional disability, and serious systemic manifestations, including cardiovascular complications 4 .Despite significant advances in therapeutic strategies, a substantial proportion of patients continue to experience persistent disease activity.Fibroblast-like synoviocytes (FLS) are central to RA pathogenesis.Their aberrant behavior plays a key role in sustaining chronic inflammation and promoting joint destruction 5,6 .In RA, FLS acquire tumor-like features, including uncontrolled proliferation, resistance to apoptosis, and elevated secretion of pro-inflammatory cytokines 7 .These pathological traits contribute to synovial hyperplasia and the release of matrix-degrading enzymes, accelerating cartilage and bone erosion 8 .Although the involvement of FLS in RA has been well established, targeted therapies specifically aimed at correcting their dysfunctional behavior remain limited 9 .ALKBH5, a member of the AlkB family of Fe(II)/αketoglutarate-dependent dioxygenases, functions as an RNA demethylase that removes N6-methyladenosine (m6A) modifications.It plays a pivotal role in the posttranscriptional regulation of gene expression by influencing AbstractObjective: To investigate the role of ALKBH5, a member of the AlkB family of Fe(II)/α-KG-dependent dioxygenases that functions as an RNA demethylase removing N6-methyladenosine (m6A), in regulating apoptosis of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS), with a focus on miR-181b-5p maturation.Methods: RA-FLS were isolated and analyzed for ALKBH5, pre-miR-181b-1, and miR-181b-5p expression using qRT-PCR.ALKBH5 protein levels were assessed by Western blotting.Cell proliferation and apoptosis were evaluated using MTT assay and flow cytometry, respectively.m6A modification on pre-miR-181b-1 was measured via MeRIP, and its binding to DGCR8 was assessed using co-immunoprecipitation.Results: ALKBH5 expression was significantly downregulated in RA-FLS.ALKBH5 overexpression inhibited proliferation and promoted apoptosis, while its knockdown had the opposite effect.ALKBH5 decreased m6A modification of pre-miR-181b-1, thereby increasing levels of pre-miR-181b-1 and mature miR-181b-5p.Inhibition of miR-181b-5p attenuated the effects of ALKBH5.Conclusion: Overexpression of ALKBH5 promotes apoptosis and inhibits proliferation in RA-FLS by demethylating m6A on pre-miR-181b-1, thereby enhancing miR-181b-5p maturation.These findings suggest a novel therapeutic target for rheumatoid arthritis.

Source: Journal of Musculoskeletal and Neuronal Interactions

DOI: 10.22540/jmni-25-440