Induction of nitric oxide synthase expression by lipopolysaccharide is mediated by calcium-dependent PKCα-ß1 in alveolar epithelial cells.
Am J Physiol Lung Cell Mol Physiol
; 305(2): L175-84, 2013 Jul 15.
Article
em En
| MEDLINE
| ID: mdl-23686852
ABSTRACT
Nitric oxide (NO) plays an important role in innate host defense and inflammation. In response to infection, NO is generated by inducible nitric oxide synthase (iNOS), a gene product whose expression is highly modulated by different stimuli, including lipopolysaccharide (LPS) from gram-negative bacteria. We reported recently that LPS from Pseudomonas aeruginosa altered Na⺠transport in alveolar epithelial cells via a suramin-dependent process, indicating that LPS activated a purinergic response in these cells. To further study this question, in the present work, we tested whether iNOS mRNA and protein expression were modulated in response to LPS in alveolar epithelial cells. We found that LPS induced a 12-fold increase in iNOS mRNA expression via a transcription-dependent process in these cells. iNOS protein, NO, and nitrotyrosine were also significantly elevated in LPS-treated cells. Ca²âº chelation and protein kinase C (PKCα-ß1) inhibition suppressed iNOS mRNA induction by LPS, implicating Ca²âº-dependent PKC signaling in this process. LPS evoked a significant increase of extracellular ATP. Because PKC activation is one of the signaling pathways known to mediate purinergic signaling, we evaluated the hypothesis that iNOS induction was ATP dependent. Although high suramin concentration inhibited iNOS mRNA induction, the process was not ATP dependent, since specific purinergic receptor antagonists could not inhibit the process. Altogether, these findings demonstrate that iNOS expression is highly modulated in alveolar epithelial cells by LPS via a Ca²âº/PKCα-ß1 pathway independent of ATP signaling.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pseudomonas aeruginosa
/
Alvéolos Pulmonares
/
Proteína Quinase C
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Regulação Enzimológica da Expressão Gênica
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Lipopolissacarídeos
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Cálcio
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Mucosa Respiratória
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Células Epiteliais
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Óxido Nítrico Sintase Tipo II
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Proteína Quinase C-alfa
Limite:
Animals
Idioma:
En
Revista:
Am J Physiol Lung Cell Mol Physiol
Assunto da revista:
BIOLOGIA MOLECULAR
/
FISIOLOGIA
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Canadá