Formyl Peptide Receptor 1 Modulates Endothelial Cell Functions by NADPH Oxidase-Dependent VEGFR2 Transactivation

Abstract EN

In the vasculature, NADPH oxidase is the main contributor of reactive oxygen species (ROS) which play a key role in endothelial signalling and functions.

We demonstrate that ECV304 cells express p47phox, p67phox, and p22phox subunits of NADPH oxidase, as well as formyl peptide receptors 1 and 3 (FPR1/3), which are members of the GPCR family.

By RT-PCR, we also detected Flt-1 and Flk-1/KDR in these cells.

Stimulation of FPR1 by N-fMLP induces p47phox phosphorylation, which is the crucial event for NADPH oxidase-dependent superoxide production.

Transphosphorylation of RTKs by GPCRs is a biological mechanism through which the information exchange is amplified throughout the cell.

ROS act as signalling intermediates in the transactivation mechanism.

We show that N-fMLP stimulation induces the phosphorylation of cytosolic Y951, Y996, and Y1175 residues of VEGFR2, which constitute the anchoring sites for signalling molecules.

These, in turn, activate PI3K/Akt and PLC-γ1/PKC intracellular pathways.

FPR1-induced ROS production plays a critical role in this cross-talk mechanism.

In fact, inhibition of FPR1 and/or NADPH oxidase functions prevents VEGFR2 transactivation and the triggering of the downstream signalling cascades.

N-fMLP stimulation also ameliorates cellular migration and capillary-like network formation ability of ECV304 cells.