Enzyme-independent nitric oxide formation during UVA challenge of human skin: characterization, molecular sources, and mechanisms.
Free Radic Biol Med
; 38(5): 606-15, 2005 Mar 01.
Article
em En
| MEDLINE
| ID: mdl-15683717
ABSTRACT
Many of the local UV-induced responses including erythema and edema formation, inflammation, premature aging, and immune suppression can be influenced by nitric oxide synthase (NOS)-produced NO which is known to play a pivotal role in cutaneous physiology. Besides NOS-mediated NO production, UV radiation might trigger an enzyme-independent NO formation in human skin by a mechanism comprising the decomposition of photo-reactive nitrogen oxides. Therefore, we have examined the chemical-storage forms of potential NO-generating agents, the mechanisms and kinetics of their decomposition, and their biological relevance. In normal human skin specimens we find nitrite and S-nitrosothiols (RSNO) at concentrations 25- or 360-fold higher than those found in plasma of healthy volunteers. UVA irradiation of human skin leads to high-output formation of bioactive NO due to photo-decomposition of RSNO and nitrite which represents the primary basis for NO formation during UVA exposure. Interestingly, reduced thiols strongly augment photo-decomposition of nitrite and are essential for maximal NO release. The enzyme-independent NO formation found in human skin opens a completely new field in cutaneous physiology and will extend our understanding of mechanisms contributing to skin aging, inflammation, and cancerogenesis.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pele
/
Raios Ultravioleta
/
Óxido Nítrico
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Free Radic Biol Med
Assunto da revista:
BIOQUIMICA
/
MEDICINA
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Alemanha