Tumor Necrosis Factor ä-Induced E-selectin Expression Is Activated by the Nuclear Factor-κB and c-JUN N-terminal Kinase/p38 Mitogen-activated Protein Kinase Pathways

E-selectin expression by endothelium is crucial for leukocyte recruitment during inflammatory responses. Transcriptional regulation of the E-selectin promoter by tumor necrosis factor (TNF) requires multiple nuclear factor-B (NF-B) binding sites and a cAMP-responsive element/activating transcription factor-like binding site designated positive domain II (PDII). Here we characterize the role of the stress-activated family of mitogen-activated protein (MAP) kinases in induced expression of this adhesion molecule. By UV cross-linking and immunoprecipitation, we demonstrated that a heterodimer of transcription factors ATF-2 and c-JUN is constitutively bound to the PDII site. TNF stimulation of endothelial cells induces transient phosphorylation of both ATF-2 and c-JUN and induces marked activation of the c-JUN N-terminal kinase (JNK1) and p38 but not extracellular signal-regulated kinase (ERK1). JNK and p38 are constitutively present in the nucleus, and DNAbound c-JUN and ATF-2 are stably contacted by JNK and p38, respectively. MAP/ERK kinase kinase 1 (MEKK1), an upstream activator of MAP kinases, increases E-selectin promoter transcription and requires an intact PDII site for maximal induction. MEKK1 can also activate NF-B -dependent gene expression. The effects of dominant interfering forms of the JNK/p38 signaling pathway demonstrate that activation of these kinases is critical for cytokine-induced E-selectin gene expression. Thus, TNF activates two signaling pathways, NF-B and JNK/p38, which are both required for maximal expression of E-selectin.