Identification of the two-phase mechanism of arachidonic acid regulating inflammatory prostaglandin E2 biosynthesis by targeting COX-2 and mPGES-1.
Arch Biochem Biophys
; 603: 29-37, 2016 08 01.
Article
en En
| MEDLINE
| ID: mdl-27177970
ABSTRACT
Through linking inducible cyclooxygenase (COX)-2 with microsomal prostaglandin E2 (PGE2) synthase-1 (mPGES-1), a Single-Chain Enzyme Complex (SCEC, COX-2-10aa-mPGES-1) was engineered to mimic a specific inflammatory PGE2 biosynthesis from omega-6 fatty acid, arachidonic acid (AA), by eliminating involvements of non-inducible COX-1 and other PGE2 synthases. Using the SCEC, we characterized coupling reactions between COX-2 and mPGES-1 at 11 ratio of inflammatory PGE2 production. AA demonstrated two phase activities to regulate inflammatory PGE2 production. In the first phase (<2 µM), AA was a COX-2 substrate and converted to increasing production of PGE2. In the second phase with a further increased AA level (2-10 µM), AA bound to mPGES-1 and inhibited the PGE2 production. The SCEC study was identical to the co-expression of COX-2 and mPGES-1. This was further confirmed by using mPGES-1 and PGH2 as a direct enzyme target and substrate, respectively. Furthermore, the carboxylic acid group of AA binding to R67 and R70 of mPGES-1 was identified by X-ray structure-based docking and mutagenesis. mPGES-1 mutants, R70A, R70K, R67A and R67K, lost 40-100% binding to [(14)C]-AA. To conclude, a cellular model, in which AA is involved in self-controlling initial initiating and later resolving inflammation by its two phase activities, was discussed.
Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Dinoprostona
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Ácido Araquidónico
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Prostaglandina H2
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Ciclooxigenasa 2
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Prostaglandina-E Sintasas
Tipo de estudio:
Diagnostic_studies
Límite:
Humans
Idioma:
En
Año:
2016
Tipo del documento:
Article