| [PMID]: | 17693621 |
| [Au] Autor: | Chen J; Yang L; Foulks JM; Weyrich AS; Marathe GK; McIntyre TM |
| [Ad] Endereço: | Department of Cell Biology, Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH 44195, USA. |
| [Ti] Título: | Intracellular PAF catabolism by PAF acetylhydrolase counteracts continual PAF synthesis. |
| [So] Source: | J Lipid Res;48(11):2365-76, 2007 Nov. |
| [Is] ISSN: | 0022-2275 |
| [Cp] País de publicação: | United States |
| [La] Idioma: | eng |
| [Ab] Resumo: | Stimulated inflammatory cells synthesize platelet-activating factor (PAF), but lysates of these cells show little enhancement in PAF synthase activity. We show that human neutrophils contain intracellular plasma PAF acetylhydrolase (PLA2G7), an enzyme normally secreted by monocytes. The esterase inhibitors methyl arachidonoylfluorophosphonate (MAFP), its linoleoyl homolog, and Pefabloc inhibit plasma PAF acetylhydrolase. All of these inhibitors induced PAF accumulation by quiescent neutrophils and monocytes that was equivalent to agonist stimulation. Agonist stimulation after esterase inhibition did not further increase PAF accumulation. PAF acetylhydrolase activity in intact neutrophils was reduced, but not abolished, by agonist stimulation. Erythrocytes, which do not participate in the acute inflammatory response, inexplicably express the type I PAF acetylhydrolase, whose only known substrate is PAF. Inhibition of this enzyme by MAFP caused PAF accumulation by erythrocytes, which was hemolytic in the absence of PAF acetylhydrolase activity. We propose that PAF is continuously synthesized by a nonselective acyltransferase activity(ies) found even in noninflammatory cells as a component of membrane remodeling, which is then selectively and continually degraded by intracellular PAF acetylhydrolase activity to modulate PAF production. |
| [Mh] Termos MeSH primário: |
1-Alquil-2-acetilglicerofosfocolina Esterase/metabolismo
Fator de Ativação de Plaquetas/biossíntese
Fator de Ativação de Plaquetas/metabolismo
|
| [Mh] Termos MeSH secundário: |
Ácidos Araquidônicos/farmacologia
Esterases/antagonistas & inibidores
Seres Humanos
Ácidos Linoleicos
Monócitos/efeitos dos fármacos
Monócitos/metabolismo
Neutrófilos/efeitos dos fármacos
Neutrófilos/metabolismo
Organofluorfosfonatos
Organofosfonatos/farmacologia
Sulfonas/farmacologia
|
| [Pt] Tipo de publicação: | JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL |
[Nm] Nome de substância:
| 0 (Arachidonic Acids); 0 (Linoleic Acids); 0 (Organofluorophosphonates); 0 (Organophosphonates); 0 (Platelet Activating Factor); 0 (Sulfones); 0 (methyl arachidonylfluorophosphonate); 0 (methyl linolenoylfluorophosphonate); 34284-75-8 (4-(2-aminoethyl)benzenesulfonylfluoride); EC 3.1.- (Esterases); EC 3.1.- (serine esterase); EC 3.1.1.47 (1-Alkyl-2-acetylglycerophosphocholine Esterase) |
| [Em] Mês de entrada: | 0712 |
| [Cu] Atualização por classe: | 121115 |
[Lr] Data última revisão:
| 121115 |
| [Sb] Subgrupo de revista: | IM |
| [Da] Data de entrada para processamento: | 070819 |
| [St] Status: | MEDLINE |
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