Iguratimod modulates osteoclast differentiation in rheumatoid arthritis: Insights into AMPK/HIF-1α signaling pathway regulation

Background

Rheumatoid arthritis (RA) leads to joint deformities and diminishes quality of life if not managed promptly. Investigating Iguratimod effects on osteoclast differentiation in RA patients could provide insights into disease management.

Methods

Peripheral blood mononuclear cells (PBMCs) were extracted from blood samples taken from RA patients. TRAP staining confirmed the ability of these cells to differentiate into osteoclasts. Those cells were treated with Iguratimod, AMPK agonist (AICAR), and HIF-1α interference (PX-478) during osteoclast induction. CCK8, flow cytometry, ELISA, qPCR, and WB were used to detect changes after exposure in each group.

Results

Iguratimod, AICAR and PX-478 reduced osteoclast formation and viability while promoting apoptosis. ELISA results showed that exposure with Iguratimod, AICAR and PX-478 significantly reduced the levels of CXCL8, CCL20, TNF-α, IL-1, IL-6, IL-17 and TPRA secreted by PBMCs from RA patients. In addition, the results demonstrate that Iguratimod, along with AICAR, PX-478, and Leflunomide, significantly suppresses the expression of osteoclast-specific markers (HIF-1α, TRAP, CTSK, CTR, MMP9, and RANK) at both mRNA and protein levels. Notably, Iguratimod, AICAR, and Leflunomide increase the expression of AMPK and p-AMPK, while PX-478 decreases their expression.

Conclusions

Iguratimod potentially modulates AMPK/HIF-1α pathway, thereby suppressing release of inflammatory factors and influencing differentiation of peripheral blood osteoclasts in RA patients. These findings suggest promising therapeutic strategies for exposure of joint deformities associated with RA.