Nitric oxide signaling via nuclearized endothelial nitric-oxide synthase modulates expression of the immediate early genes iNOS and mPGES-1

Fernand Gobeil, Tang Zhu, Sonia Brault, Antoinette Geha, Alejandro Vazquez-Tello, Audrey Fortier, David Barbaz, Daniella Checchin, Xin Hou, Moni Nader, Ghassan Bkaily, Jean Philippe Gratton, Nikolaus Heveker, Alfredo Ribeiro-da-Silva, Krishna Peri, Harry Bard, Alzbeta Chorvatova, Pedro D'Orléans-Juste, Edward J. Goetzl, Sylvain Chemtob

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75 Scopus citations


Stimulation of freshly isolated rat hepatocytes with lysophosphatidic acid (LPA) resulted in LPA1 receptor-mediated and nitricoxide-dependent up-regulation of the immediate early genes iNOS (inducible nitric-oxide synthase (NOS)) and mPGES-1 (microsomal prostaglandin E synthase-1). Because LPA is a ligand for both cell surface and intracellular receptor sites and a potent endothelial NOS (eNOS) activator, we hypothesized that NO derived from activated nuclearized eNOS might participate in gene regulation. Herein we show, by confocal microscopy performed on porcine cerebral endothelial cells expressing native LPA1-receptor and eNOS and on HTC4 rat hepatoma cells co-transfected with recombinant human LPA1-receptor and fused eNOS-GFP cDNA, a dynamic eNOS translocation from peripheral to nuclear regions upon stimulation with LPA. Nuclear localization of eNOS and its downstream effector, soluble guanylate cyclase, were demonstrated in situ in rat liver specimens by immunogold labeling using specific antibodies. Stimulation of this nuclear fraction with LPA and the NO donor sodium nitroprusside resulted, respectively, in increased production of nitrite (and eNOS phosphorylation) and cGMP; these separate responses were also correspondingly blocked by NOS inhibitor L-NAME and soluble guanylate cyclase inhibitor ODQ. In addition, sodium nitroprusside evoked a sequential increase in nuclear Ca2+ transients, activation of p42 MAPK, NF-κB binding to DNA consensus sequence, and dependent iNOS RNA. This study describes a hitherto unrecognized molecular mechanism by which nuclear eNOS through ensuingNOmodulates nuclear calcium homeostasis involved in gene transcription-associated events. Moreover, our findings strongly support the concept of the nucleus as an autonomous signaling compartment.

Original languageBritish English
Pages (from-to)16058-16067
Number of pages10
JournalJournal of Biological Chemistry
Issue number23
StatePublished - 9 Jun 2006


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