TNF and rheumatoid arthritis: Recently, Hu et al. reported that HIF-1α was able to directly potentiate the production of inflammatory cytokines (IL-6, IL-8, TNF-α, and IL-1β) and cell-cell contact mediators [IL-15, vascular cell adhesion molecule-1 (VCAM-1), thrombospondin-1 (TSP-1), and stromal cell-derived factor-1 (SDF-1/CXCL12)] in rheumatoid arthritis synovial fibroblasts (RASF; Hu et al., 2016).