NPY, NPY receptors, and DPP IV activity are modulated by LPS, TNF-α and IFN-γ in HUVEC

Since NPY increases endothelial cell (EC) stickiness for leukocytes, we studied the effects of LPS, TNF-alpha and IFN-gamma on its expression and action in HUVEC. Cytokines raised NPY and pro-NPY intracellular content and dipeptidyl peptidase IV (DPP IV) activity. Y1 and Y2 receptors were expressed in basal conditions, and LPS, TNF-alpha and IFN-gamma induced Y5 receptor expression with a concomitant extinction of Y2 receptor expression. NPY induced an intracellular calcium increase mainly mediated by Y2 and Y5 receptors in basal conditions. After stimulation with LPS, TNF-alpha and IFN-gamma, calcium increase was mainly caused by Y5 receptor. The modulation of the NPY system by LPS, TNF-alpha and IFN-gamma, and the NPY-induced calcium signaling suggest a role for NPY during the inflammatory response. (C) 2003 Elsevier B.V. All rights reserved.