title: 16K-prolactin inhibits activation of endothelial nitric oxide synthase, intracellular calcium mobilization, and endothelium-dependent vasorelaxation.
abstract: Activation of endothelial nitric oxide synthase (eNOS) and subsequent nitric oxide production (NO) are events that mediate the effect of important angiogenic, vasopermeability, and vasorelaxation factors, including vascular endothelial growth factor (VEGF), bradykinin (BK), and acetylcholine (ACh). The N-terminal 16-kDa fragment of prolactin (16K-PRL) acts on endothelial cells to inhibit angiogenesis both in vivo and in vitro. Here, we show that 16K-PRL inhibits VEGF-induced eNOS activation in endothelial cells. Inhibition of eNOS activation may mediate the antiangiogenic properties of 16K-PRL, because the NO donor (Z)-1-[2-(2-aminoethyl)- N-(2-ammonio-ethyl)amino]diazen-1-ium-1,2-diolate (DETANONOate) prevented 16K-PRL from blocking the VEGF-induced proliferation of endothelial cells. In addition, 16K-PRL inhibited eNOS activation by BK and blocked the BK-evoked transient increase in intracellular Ca(2+) in endothelial cells. This finding suggests that 16K-PRL interferes with the mobilization of intracellular Ca(2+), thereby inhibiting the Ca(2+)-dependent activation of eNOS. Blockage of eNOS activation can lead to inhibition of vasodilation. Consistently, 16K-PRL inhibited BK-induced relaxation of coronary vessels in isolated perfused guinea pig hearts. Moreover, 16K-PRL inhibited eNOS activation induced by ACh, and this action resulted in the inhibition of both ACh-evoked relaxation of coronary vessels in isolated perfused rat hearts and ACh-induced, endothelium-dependent relaxation of rat aortic segments. In conclusion, 16K-PRL can block the Ca(2+)-mediated activation of eNOS by three different vasoactive substances, and this action results in the inhibition of both angiogenesis and vasorelaxation.
authors.affiliation: Neurobiology Institute, National University of México, Querétaro, QRO, México.
authors.forename: Carmen
authors.initials: C
authors.lastname: Gonzalez
authors.forename: Ana M
authors.initials: AM
authors.lastname: Corbacho
authors.forename: Jason P
authors.initials: JP
authors.lastname: Eiserich
authors.forename: Celina
authors.initials: C
authors.lastname: Garcia
authors.forename: Fernando
authors.initials: F
authors.lastname: Lopez-Barrera
authors.forename: Veronica
authors.initials: V
authors.lastname: Morales-Tlalpan
authors.forename: Alma
authors.initials: A
authors.lastname: Barajas-Espinosa
authors.forename: Mauricio
authors.initials: M
authors.lastname: Diaz-Muñoz
authors.forename: Rafael
authors.initials: R
authors.lastname: Rubio
authors.forename: Sue-Hwa
authors.initials: SH
authors.lastname: Lin
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Martinez de la Escalera
authors.forename: Carmen
authors.initials: C
authors.lastname: Clapp
mesh_terms: D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D006168:Guinea Pigs; D006801:Humans; D008297:Male; D018919:Neovascularization, Physiologic / Q000187:drug effects; D009569:Nitric Oxide / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III; D011388:Prolactin / Q000737:chemistry / Q000494:pharmacology*; D017434:Protein Structure, Tertiary; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D014471:Umbilical Veins / Q000166:cytology; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D042461:Vascular Endothelial Growth Factor A; D009569:Nitric Oxide; D011388:Prolactin; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D001920:Bradykinin; D002118:Calcium