Double-label expression studies of prostacyclin synthase, thromboxane synthase and COX isoforms in normal aortic endothelium.
Biochim Biophys Acta
; 1771(1): 45-54, 2007 Jan.
Article
en En
| MEDLINE
| ID: mdl-17189713
We have performed double-label immunofluorescence microscopy studies to evaluate the extent of co-localization of prostacyclin synthase (PGIS) and thromboxane synthase (TXS) with cyclooxygenase (COX)-1 and COX-2 in normal aortic endothelium. In dogs, COX-2 expression was found to be restricted to small foci of endothelial cells while COX-1, PGIS and TXS were widely distributed throughout the endothelium. Quantification of the total cross-sectioned aortic endothelium revealed a 6- to 7-fold greater expression of COX-1 relative to COX-2 (55 vs. 8%) and greater co-distribution of PGIS with COX-1 compared to COX-2 (19 vs. 3%). These results are in contrast to the extensive co-localization of PGIS and COX-2 in bronchiolar epithelium. In rat and human aortas, immunofluorescence studies also showed significant COX-1 and PGIS co-localization in the endothelium. Only minor focal COX-2 expression was detected in rat endothelium, similar to the dog, while COX-2 was not detected in human specimens. Inhibition studies in rats showed that selective COX-1 inhibition caused a marked reduction of 6-keto-PGF(1alpha) and TXB(2) aortic tissue levels, while COX-2 inhibition had no significant effect, providing further evidence for a functionally larger contribution of COX-1 to the synthesis of prostacyclin and thromboxane in aortic tissue. The data suggest a major role for COX-1 in the production of both prostacyclin and thromboxane in normal aortic tissue. The extensive co-localization of PGIS and COX-2 in the lung also indicates significant tissue differences in the co-expression patterns of these two enzymes.
Buscar en Google
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Aorta
/
Tromboxano-A Sintasa
/
Endotelio Vascular
/
Regulación Enzimológica de la Expresión Génica
/
Prostaglandina-Endoperóxido Sintasas
/
Oxidorreductasas Intramoleculares
/
Sistema Enzimático del Citocromo P-450
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Biochim Biophys Acta
Año:
2007
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Países Bajos