PGC-1β overexpression remarkably exacerbated RA-FLS-mediated inflammation, as evidenced by upregulating TNF-α, IL-6, IL-8, RANKL, MMP-3 and MMP-13 expression, but not IL-1β (Figure 4B and 4C). The gene discussed is CXCL8; the disease is rheumatoid arthritis.