Group V secreted phospholipase A2 contributes to LPS-induced leukocyte recruitment.
Secreted phospholipases A(2) (sPLA(2)s) are well known for their contribution in the biosynthesis of inflammatory eicosanoids. These enzymes also participate in the inflammatory process by regulating chemokine production and protein expression of adhesion molecules. The majority of sPLA(2) isoforms are up-regulated by proinflammatory stimuli such as bacterial lipopolysaccharide (LPS), which predominantly increases the expression of group V sPLA(2) (sPLA(2)-V). Furthermore, it has recently been shown that sPLA(2)-V is a critical messenger in the regulation of cell migration during allergic airway responsiveness. Herein, we investigated the effect of sPLA(2)-V on LPS-mediated leukocyte recruitment and its capacity to modulate adhesion molecule expression. We conducted our study in the murine air pouch model, using sPLA(2)-V null mice (sPLA(2)-V(-/-)) and control wild-type (WT) littermates. We observed that LPS (1 microg/ml)-mediated leukocyte emigration in sPLA(2)-V(-/-) was attenuated by 52% and 86% upon 6 and 12 h of treatment respectively, as compared to WT mice. In WT mice, treatment with the cell-permeable sPLA(2) inhibitor (12-epi-scalaradial; SLD) reduced LPS-mediated leukocyte recruitment by 67%, but had no additional inhibitory effect in sPLA(2)-V(-/-) mice. Protein analyses from the air pouch skin were carried out upon LPS-challenge, and the expression of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 were both significantly reduced in sPLA(2)-V(-/-) mice as compared to control WT mice. Together, our data demonstrate the role of sPLA(2)-V in LPS-induced ICAM-1 and VCAM-1 protein overexpression and leukocyte recruitment, supporting the contribution of sPLA(2)-V in the development of inflammatory innate immune responses.
Lapointe
Stéphanie
S
Research Centre, Montreal Heart Institute, Université de Montréal, Montreal, QC, Canada.
Brkovic
Alexandre
A
Cloutier
Isabelle
I
Tanguay
Jean-François
JF
Arm
Jonathan P
JP
Sirois
Martin G
MG
D000818:Animals; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D054505:Group V Phospholipases A2 / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D007113:Immunity, Innate; D007249:Inflammation / Q000139:chemically induced / Q000201:enzymology* / Q000276:immunology / Q000517:prevention & control; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D007962:Leukocytes / Q000187:drug effects / Q000201:enzymology* / Q000276:immunology; D008070:Lipopolysaccharides; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020556:Neutrophil Infiltration / Q000187:drug effects; D013997:Time Factors; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism
D004791:Enzyme Inhibitors; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D019010:Vascular Cell Adhesion Molecule-1; C440499:lipopolysaccharide, Escherichia coli O111 B4; D018799:Intercellular Adhesion Molecule-1; D054505:Group V Phospholipases A2; C516300:Pla2g5 protein, mouse