title: Rapid NOS-1-derived nitric oxide and peroxynitrite formation act as signaling agents for inducible NOS-2 expression in vascular smooth muscle cells.
abstract: Septic vascular dysfunction is characterized by hypotension and hyporeactivity to vasoconstrictors and nitric oxide (NO), reactive oxygen species and peroxynitrite have a prominent role in this condition. However, the mechanism whereby the vascular dysfunction is initiated is poorly understood. Based on previous studies of our group and the literature,we hypothesize that constitutive nitric oxide synthases (c-NOS) and peroxynitrite may play a role in the development of septic vascular dysfunction. Bacterial lipopolysaccharide (LPS) and interferon-γ (IFN) were used to stimulate rat aorta smooth muscle cells (A7r5) and rat aorta slices. This stimulation led to a rapid (within minutes) production of NO and superoxide anion, which led to peroxynitrite formation. When this rapid initial burst was reduced, through the inhibition of c-NOS and NADPH oxidases (NOX) or the scavenging of NO and superoxide the NF-κB activation, NOS-2 expression and nitrite production were significantly attenuated. Although vascular smooth muscle cells express both c-NOS isoforms, gene knockdown revealed that only NOS-1-dependent NO and peroxynitrite formation are important for the later NOS-2 expression. Similar findings were obtained by knockdown NOX-1 gene, one source of superoxide for peroxynitrite formation. Taking together, we show that smooth muscle cell activation by LPS/IFN leads to a rapid formation of NOS-1-derived NO and NOX-1-derived superoxide, forming peroxynitrite; and that this species act as a trigger for NOS-2 expression through NF-κB activation. Therefore, our findings suggest a critical role for NOS-1 and NOX-1 in the initiation of the vascular dysfunction associated with sepsis and septic shock.
authors.affiliation: Department of Pharmacology, Universidade Federal de Santa Catarina, Santa Catarina, Brazil. Electronic address: karin.scheschowitsch@gmail.com.
authors.forename: Karin
authors.initials: K
authors.lastname: Scheschowitsch
authors.affiliation: Department of Cell Biology, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: jmoraesbr@yahoo.com.
authors.forename: João Alfredo
authors.initials: JA
authors.lastname: de Moraes
authors.affiliation: Department of Pharmacology, Universidade Federal de Santa Catarina, Santa Catarina, Brazil. Electronic address: reginadesordi@gmail.com.
authors.forename: Regina
authors.initials: R
authors.lastname: Sordi
authors.affiliation: Department of Cell Biology, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: barja-fidalgo@uerj.br.
authors.forename: Christina
authors.initials: C
authors.lastname: Barja-Fidalgo
authors.affiliation: Department of Pharmacology, Universidade Federal de Santa Catarina, Santa Catarina, Brazil. Electronic address: jamil.assreuy@ufsc.br.
authors.forename: Jamil
authors.initials: J
authors.lastname: Assreuy
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism; D002460:Cell Line; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D019255:NADPH Oxidases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D030421:Peroxynitrous Acid / Q000378:metabolism*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D012772:Shock, Septic / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013481:Superoxides / Q000378:metabolism
chemical_list: D008070:Lipopolysaccharides; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D013481:Superoxides; D030421:Peroxynitrous Acid; D009569:Nitric Oxide; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D019255:NADPH Oxidases
keywords: 7-Nitroindazole (PubChem CID: 1893); Carboxy-PTIO, potassium salt (PubChem CID: 2733502); Diphenyleneiodonium chloride (PubChem CID: 2733504); FeTPPs (PubChem CID: 5380171); Glyceryl trinitrate (PubChem CID: 4510); Heme (PubChem CID: 26945); Nitric oxide; Nitric oxide synthases (NOS); Peroxynitrite; SIN-1 (PubChem CID: 9859122); Vascular smooth muscle