Objectives: Macrophage ferroptosis is linked to the pathogenesis of gouty arthritis (GA), yet the precise regulatory mechanism needs to be elucidated. This study aimed to investigate the role of macrophage ferroptosis in GA and its potential mechanisms. Methods: THP-1 macrophages were stimulated with monosodium urate (MSU) crystals to simulate the GA model. The co-culture system of macrophages and primary chondrocytes (hCDs) was employed to analyze the effects of macrophage-mediated inflammation on chondrocyte degeneration. Results: MSU stimulation induced ferroptosis in macrophages, accompanied by increased methyltransferase-like 3 (METTL3) expression (p = 0.003) and total m6A modification level (p = 0.0058). In MSU-induced macrophages, phosphatase and tensin homolog (PTEN) knockdown activated the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway (p < 0.0001), downregulated glutathione peroxidase 4 (GPX4; p = 0.0006), solute carrier family 7 member 11 (SLC7A11; p < 0.0001), glutathione (GSH; p = 0.0149), and superoxide dismutase (SOD; p = 0.0165) levels, and enhanced lipid peroxidation, malondialdehyde (MDA; p < 0.0001), Fe2+ (p < 0.0001), and pro-inflammatory cytokines (p < 0.01). Additionally, PTEN knockdown in macrophages reduced the co-localization of GPX4 and cluster of differentiation 68 (CD68; p < 0.0001), promoting macrophage ferroptosis. Co-culture with PTEN-knockdown macrophages impaired hCD viability, elevating MMP3 (p < 0.0001) while reducing Collagen II (p < 0.0001) and Aggrecan (p < 0.0001). Mechanistically, METTL3 decreased PTEN mRNA stability (p < 0.0001) and gene expression by m6A modification. The m6A reader YT521-B homology domain family protein 2 (YTHDF2) interacted with PTEN (p < 0.0001). METTL3/YTHDF2-mediated PTEN led to activation of the PI3K/AKT pathway and promotion of ferroptosis and inflammation. Conclusions: METTL3/YTHDF2-mediated PTEN drives GA progression by modulating the PI3K/AKT pathway in macrophages, which induces ferroptosis and chondrocyte degeneration. Targeting METTL3-mediated m6A modification and PTEN may represent promising therapeutic strategies for arthritis.
Yang et al. (Thu,) studied this question.