AbstractInterleukin‐1β (IL‐1β) has been shown to induce the expression of adhesion molecules on various cell types and contributes to inflammatory responses. However, the molecular mechanisms by which IL‐1β induced intercellular adhesion molecule (ICAM)‐1 expression remain unclear in human rheumatoid arthritis synovial fibroblasts (RASFs). Here, we demonstrated that IL‐1β induces ICAM‐1 gene expression via the de novo protein synthesis through transcription and translation, which is attenuated by pretreatment with actinomycin D and cycloheximide, respectively. IL‐1β‐induced ICAM‐1 expression, extracellular signal‐regulated kinase (ERK) and c‐Jun‐N‐terminal kinase (JNK) phosphorylation, AP‐1 activation, and nuclear factor‐κB (NF‐κB) p65 translocation were attenuated by the inhibitors of MEK1/2 (U0126), JNK (SP600125), AP‐1 (tanshinone IIA), and NF‐κB (helenalin) or transfection with respective short hairpin RNA plasmids. Moreover, IL‐1β‐stimulated NF‐κB p65 translocation was blocked by helenalin, but not by U0126 or SP600125, revealing that MAPKs and NF‐κB pathways were independent on these responses. IL‐1β‐stimulated AP‐1 activation was blocked by U0126 or SP600125, revealing that ERK and JNK linked to AP‐1 on these responses. IL‐1β‐stimulated ICAM‐1 gene expression was attenuated by pretreatment with U0126, SP600125, tanshinone IIA, or helenalin, revealed by ICAM‐1 promoter assay and real‐time RT‐PCR analysis. Finally, up‐regulation of ICAM‐1 enhanced the adhesion of leukocytes to RASFs exposed to IL‐1β. These results suggest that in human RASFs, activation of ERK, JNK, AP‐1, and NF‐κB are essential for IL‐1β‐induced ICAM‐1 expression and leukocyte adhesion. J. Cell. Physiol. 224: 516–526, 2010. © 2010 Wiley‐Liss, Inc.