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Cyclooxygenase-2 gene transcription in a macrophage model of inflammation.
Kang, Yeon-Joo; Wingerd, Byron A; Arakawa, Toshi; Smith, William L.
Afiliação
  • Kang YJ; Cell and Molecular Biology Program, Michigan State University, East Lansing, MI 48824, USA.
J Immunol ; 177(11): 8111-22, 2006 Dec 01.
Article em En | MEDLINE | ID: mdl-17114486
ABSTRACT
Infections involving LPS-bearing, Gram-negative bacteria can lead to acute inflammation and septic shock. Cyclooxygenase-2 (COX-2), the target of nonsteroidal anti-inflammatory drugs and selective COX-2 inhibitors, is importantly involved in these responses. We examined the dynamics of COX-2 gene expression in RAW264.7 murine macrophages treated with LPS as a model for COX-2 gene expression during inflammation. We established, using Northern blotting, nuclear run-on assays, and RT-PCR, that COX-2 transcriptional activation continues for at least 12 h after LPS treatment and involves at least three phases. Previous studies with murine macrophages identified an NF-kappaB site, a C/EBP site, and a cAMP response element-1 (CRE-1) as cis-acting elements in the COX-2 promoter. We identified three additional functional elements including a second CRE (CRE-2), an AP-1 site, and an E-box that overlaps CRE-1. The E-box mediates transcriptional repression whereas the other cis-elements are activating. Using electrophoretic mobility supershift and chromatin immunoprecipitation assays, we cataloged binding to each functional cis element and found them occupied to varying extents and by different transcription factors during the 12 h following LPS treatment. This suggests that the cis elements and their cognate transcription factors participate in a sequential, coordinated regulation of COX-2 gene expression during an inflammatory response. In support of this concept, we found, using inhibitors of Jun kinase and NF-kappaB p50 nuclear localization, that COX-2 gene transcription was completely dependent on phospho-c-Jun plus p50 at 6 h after LPS treatment but was only partially dependent on the combination of these factors at later treatment times.
Assuntos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Transcrição Gênica / Regulação da Expressão Gênica / Modelos Imunológicos / Ciclo-Oxigenase 2 / Inflamação / Macrófagos Tipo de estudo: Prognostic_studies Limite: Animals Idioma: En Revista: J Immunol Ano de publicação: 2006 Tipo de documento: Article País de afiliação: Estados Unidos
Buscar no Google
Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Transcrição Gênica / Regulação da Expressão Gênica / Modelos Imunológicos / Ciclo-Oxigenase 2 / Inflamação / Macrófagos Tipo de estudo: Prognostic_studies Limite: Animals Idioma: En Revista: J Immunol Ano de publicação: 2006 Tipo de documento: Article País de afiliação: Estados Unidos