Kinin B1 receptor expression and function on human brain endothelial cells

The kinin B-1 receptor is an inducible receptor expressed in response to inflammatory mediators. We sought to determine whether kinin B-1 receptor can be expressed on human brain endothelial cells (HBECs) in vitro and whether signaling via this receptor can regulate permeability and chemokine production properties of these cells. Multiplex RT-PCR amplification and western blot techniques were used to evaluate B-1 receptor expression by HBECs. Although B-1 receptor mRNA and protein could not be detected on resting HBECs, interferon-gamma induced a dose- and time-dependent up-regulation of B-1 receptor mRNA and protein on HBECs. Stimulation of interferon-gamma-treated HBECs with the selective B-1 agonist R-838 (Sar [D-Phe(8)] des Arg(9)-BK) induced a dose- and time-dependent increase in the production of inositol 3,4,5 tri-phosphate and nitric oxide. Permeability of the HBECs monolayer, as measured by BSA diffusion, was significantly increased by application of the B-1 agonist. This biological effect of R-838 could be prevented by R-715, a B-1 receptor antagonist and by L-NAME, a nitric oxide synthase blocker. R-838 also inhibited interleukin-8 release from HBECs. We demonstrate that B-1 receptors can be up regulated on the surface of KBECs by molecules released during inflammatory response and that signaling via this receptor can regulate BBB permeability and chemokine production in vitro.