Substance P activates coincident NF-AT- and NF-kappa B-dependent adhesion molecule gene expression in microvascular endothelial cells through intracellular calcium mobilization

Upon stimulation, cutaneous sensory nerves release neuropeptides such as su bstance P (SP), which modulate responses in the skin by activating a number of target cells via neurokinin receptors. We have demonstrated that SP pre ferentially binds to the NK-1R on human dermal microvascular cells, resulti ng in increased intracellular Ca2+ and induction of ICAM-1 and VCAM-1 expre ssion. In the current studies, we identify specific elements in the regulat ory regions of ICAM-1 and VCAM-1 genes as necessary and sufficient for SP-d ependent transcriptional activation. SP treatment of human dermal microvasc ular endothelial cells leads to coincident activation and binding of the tr anscription factor NF-AT to the -191/-170 region of the ICAM-1 gene (a regi on bound by activated p65/p65 homodimers in response to TNF-alpha), and NF- kappa B (p65/p50) to tandem NF-kappa B binding sites at -76/-52 of the VCAM -1 gene. The SP-elicited intracellular Ca2+ signal was required for activat ion and subsequent binding of both NF-AT and NF-kappa B. The transacting fa ctor induction by SP was specific, since a selective NK-1R antagonist block ed SP activation and subsequent NF-AT and NF-kappa B activation add binding . These data demonstrate coincident activation of NF-AT and NF-kappa B via SP-induced intracellular Ca2+ mobilization and indicate a crucial role for neuropeptides in modulating localized cutaneous inflammatory responses.