Groups IV, V, and X phospholipases A2s in human neutrophils: role in eicosanoid production and gram-negative bacterial phospholipid hydrolysis.
The bacterial tripeptide formyl-Met-Leu-Phe (fMLP) induces the secretion of enzyme(s) with phospholipase A(2) (PLA(2)) activity from human neutrophils. We show that circulating human neutrophils express groups V and X sPLA(2) (GV and GX sPLA(2)) mRNA and contain GV and GX sPLA(2) proteins, whereas GIB, GIIA, GIID, GIIE, GIIF, GIII, and GXII sPLA(2)s are undetectable. GV sPLA(2) is a component of both azurophilic and specific granules, whereas GX sPLA(2) is confined to azurophilic granules. Exposure to fMLP or opsonized zymosan results in the release of GV but not GX sPLA(2) and most, if not all, of the PLA(2) activity in the extracellular fluid of fMLP-stimulated neutrophils is due to GV sPLA(2). GV sPLA(2) does not contribute to fMLP-stimulated leukotriene B(4) production but may support the anti-bacterial properties of the neutrophil, because 10-100 ng per ml concentrations of this enzyme lead to Gram-negative bacterial membrane phospholipid hydrolysis in the presence of human serum. By use of a recently described and specific inhibitor of cytosolic PLA(2)-alpha (group IV PLA(2)alpha), we show that this enzyme produces virtually all of the arachidonic acid used for the biosynthesis of leukotriene B(4) in fMLP- and opsonized zymosan-stimulated neutrophils, the major eicosanoid produced by these pro-inflammatory cells.
Degousee
Norbert
N
Division of Vascular Surgery, Max Bell Research Center, Toronto General Hospital, University Health Network, Toronto M5G 2C4, Canada.
Ghomashchi
Farideh
F
Stefanski
Eva
E
Singer
Alan
A
Smart
Brian P
BP
Borregaard
Niels
N
Reithmeier
Reinhardt
R
Lindsay
Thomas F
TF
Lichtenberger
Cornelia
C
Reinisch
Walter
W
Lambeau
Gerard
G
Arm
Jonathan
J
Tischfield
Jay
J
Gelb
Michael H
MH
Rubin
Barry B
BB
D015153:Blotting, Western; D002219:Carbamates / Q000494:pharmacology; D002469:Cell Separation; D003600:Cytosol / Q000201:enzymology; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015777:Eicosanoids / Q000096:biosynthesis; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000378:metabolism; D005434:Flow Cytometry; D054513:Group IV Phospholipases A2; D054505:Group V Phospholipases A2; D054509:Group X Phospholipases A2; D006801:Humans; D006868:Hydrolysis; D007212:Indolizines / Q000494:pharmacology; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000201:enzymology* / Q000378:metabolism; D010740:Phospholipases / Q000145:classification* / Q000502:physiology*; D010741:Phospholipases A / Q000096:biosynthesis* / Q000737:chemistry; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014158:Transcription, Genetic
D002219:Carbamates; D018076:DNA, Complementary; D015777:Eicosanoids; D004791:Enzyme Inhibitors; D007212:Indolizines; D012333:RNA, Messenger; D011994:Recombinant Proteins; C119389:indoxam; D009240:N-Formylmethionine Leucyl-Phenylalanine; D010740:Phospholipases; D010741:Phospholipases A; D054513:Group IV Phospholipases A2; D054505:Group V Phospholipases A2; D054509:Group X Phospholipases A2; C516365:PLA2G10 protein, human; C516389:PLA2G4A protein, human; C516299:PLA2G5 protein, human