title: The role of inducible nitric oxide synthase and haem oxygenase 1 in growth and development of dental tissue'.
abstract: In this study, the activity of the antioxidant enzyme network was assessed spectrophotometrically in samples of dental pulp and dental papilla taken from third-molar gem extracts. The production of nitric oxide by the conversion of l-(2,3,4,5)-[3H] arginine to l-(3H) citrulline, the activity of haem oxygenase 1 (HO-1) through bilirubin synthesis and the expression of inducible nitric oxide synthase (iNOS), HO-1 proteins and messenger RNA by Western blot and reverse-transcribed polymerase chain reaction were also tested. The objective of this study was to evaluate the role of two proteins, iNOS and HO-1, which are upregulated by a condition of oxidative stress present during dental tissue differentiation and development. This is fundamental for guaranteeing proper homeostasis favouring a physiological tissue growth. The results revealed an over-expression of iNOS and HO-1 in the papilla, compared with that in the pulp, mediated by the nuclear factor kappa B transcription factor activated by the reactive oxygen species that acts as scavengers for the superoxide radicals. HO-1, a metabolically active enzyme in the papilla, but not in the pulp, seems to inhibit the iNOS enzyme by a crosstalk between the two proteins. We suggest that the probable mechanism through which this happens is the interaction of HO-1 with haem, a cofactor dimer indispensible for iNOS, and the subsequent suppression of its metabolic activity.
authors.affiliation: Department of Human Movement Sciences, University G. D'Annunzio, Chieti, Italy. l.speranza@unich.it
authors.forename: Lorenza
authors.initials: L
authors.lastname: Speranza
authors.forename: Mirko
authors.initials: M
authors.lastname: Pesce
authors.forename: Sara
authors.initials: S
authors.lastname: Franceschelli
authors.forename: Filiberto
authors.initials: F
authors.lastname: Mastrangelo
authors.forename: Antonia
authors.initials: A
authors.lastname: Patruno
authors.forename: Maria Anna
authors.initials: MA
authors.lastname: De Lutiis
authors.forename: Stefano
authors.initials: S
authors.lastname: Tetè
authors.forename: Mario
authors.initials: M
authors.lastname: Felaco
authors.forename: Alfredo
authors.initials: A
authors.lastname: Grilli
mesh_terms: D000293:Adolescent; D002648:Child; D003771:Dental Papilla / Q000201:enzymology* / Q000254:growth & development*; D003786:Dental Pulp Cavity / Q000201:enzymology* / Q000254:growth & development*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D051547:Heme Oxygenase-1 / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008297:Male; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D016328:NF-kappa B; D052247:Nitric Oxide Synthase Type II; D051547:Heme Oxygenase-1