Xinfeng capsule regulates pyroptosis and ameliorates cardiac fibrosis in rheumatoid arthritis through lncRNA GAS5 and TLR4/ROS/miR-21 pathways.

Xinfeng capsule (XFC) is a traditional Chinese medicinal compound that has been used clinically for several years to treat rheumatoid arthritis (RA)-related cardiac dysfunction. Nevertheless, the mechanism through which XFC treats RA-induced cardiac impairment remains unclear. This study investigates the mechanism by which XFC-containing serum regulates pyroptosis and ameliorates cardiac fibrosis in RA through the lncRNA GAS5 and TLR4/ROS/miR-21 pathways. A cardiac fibrosis model using human myocardial cells was established to study lncRNA GAS5, miR-21, TLR4, and NLRP3 expressions. Immunofluorescence, RT-qPCR, WB, dual-luciferase assay, CCK-8, flow cytometry, electron microscopy, and enzyme-linked immunosorbent assay were used to analyze various cellular processes and protein levels. Lactate dehydrogenase (LDH) releases were also analyzed. The mRNA and protein expressions of multiple genes were assessed. The optimal intervention conditions for AC16 cells were determined as follows: 20 µg/L for lipopolysaccharide (LPS) for 24 h, and 10% for XFC. In the LPS group, cell viability decreased, LDH release increased, and there was an elevation in pro-inflammatory cytokines and pyroptosis-related protein expression. GAS5 expression was reduced, while TLR4, ROS, and miR-21 showed increased levels compared to the NC group. GAS5 acted as an inhibitor by sponging miR-21. Conversely, XFC-containing serum, GAS5 overexpression, and miR-21 inhibition exhibited positive effects - enhancing cell viability, preventing LDH and pro-inflammatory cytokine release, and reducing pyroptosis and fibrosis-related protein levels. XFC can inhibit cellular pyroptosis, reduce pro-inflammatory cytokine levels, and improve RA cardiac fibrosis via lncRNA GAS5 and TLR4/ROS/miR-21 pathways.