Role of activating transcription factor 3 as a mediator of the protective effects of berberine against lipopolysaccharide-stimulated SW982 cells and in rheumatoid arthritis animal models

Abstract

This study aimed to explore the protective effects of berberine against rheumatoid arthritis (RA) and clarify the role of activating transcription factor 3 (ATF3) in the mechanism of action of berberine, using a lipopolysaccharide (LPS)-stimulated SW982 human synovial cell line. Berberine treatment resulted in a concentration-dependent reduction in LPS-induced proinflammatory cytokines and matrix metalloproteinases (MMPs) in SW982 cells. These inhibitory effects were associated with increased ATF3 expression, reduced nuclear translocation of nuclear factor-κB (NF-κB), and diminished phosphorylation of mitogen-activated protein kinase (MAPK). In contrast, ATF3 knockdown reversed the suppressive effects of berberine on proinflammatory cytokines and MMP production, leading to enhanced MAPK phosphorylation; however, it had minimal impact on adenosine monophosphate-activated protein kinase (AMPK) phosphorylation. Furthermore, AMPK knockdown negated the protective effects of berberine and reduced ATF3 levels, whereas treatment with 5-aminoimidazole-4-carboxamide ribonucleotide, an AMPK activator, replicated the beneficial effects of berberine. In an in vivo collagen-induced arthritis (CIA) mouse model, intraperitoneal administration of berberine significantly reduced paw edema and arthritis severity, accompanied by ATF3 induction and increased AMPK phosphorylation in the synovial tissue. These findings highlighted the pivotal role of ATF3 in mediating the protective effects of berberine in RA- and LPS-activated synoviocytes, suggesting its potential as a therapeutic agent for RA management.