Presence of the M-type sPLA(2) receptor on neutrophils and its role in elastase release and adhesion.
Secretory phospholipase A(2) (sPLA(2)) produces lipids that stimulate polymorphonuclear neutrophils (PMNs). With the discovery of sPLA(2) receptors (sPLA(2)-R), we hypothesize that sPLA(2) stimulates PMNs through a receptor. Scatchard analysis was used to determine the presence of a sPLA(2) ligand. Lysates were probed with an antibody to the M-type sPLA(2)-R, and the immunoreactivity was localized. PMNs were treated with active and inactive (+EGTA) sPLA(2) (1-100 units of enzyme activity/ml, types IA, IB, and IIA), and elastase release and PMN adhesion were measured. PMNs incubated with inactive, FITC-linked sPLA(2)-IB, but not sPLA(2)-IA, demonstrated the presence of a sPLA(2)-R with saturation at 2.77 fM and a K(d) of 167 pM. sPLA(2)-R immunoreactivity was present at 185 kDa and localized to the membrane. Inactive sPLA(2)-IB activated p38 MAPK, and p38 MAPK inhibition attenuated elastase release. Active sPLA(2)-IA caused elastase release, but inactive type IA did not. sPLA(2)-IB stimulated elastase release independent of activity; inactive sPLA(2)-IIA partially stimulated PMNs. sPLA(2)-IB and sPLA(2)-IIA caused PMN adhesion. We conclude that PMNs contain a membrane M-type sPLA(2)-R that activates p38 MAPK.
Silliman
Christopher C
CC
Bonfils Blood Center, Department of Pediatrics, University of Colorado School of Medicine, Denver, CO 80262, USA.
Moore
Ernest E
EE
Zallen
Garret
G
Gonzalez
Ricardo
R
Johnson
Jeffrey L
JL
Elzi
David J
DJ
Meng
Xianzhong
X
Hanasaki
Kohji
K
Ishizaki
Jun
J
Arita
Hitoshi
H
Ao
Lihua
L
England
Kelly M
KM
Banerjee
Anirban
A
D001667:Binding, Competitive / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D002469:Cell Separation; D002614:Chelating Agents / Q000378:metabolism / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D054500:Group IB Phospholipases A2; D054501:Group II Phospholipases A2; D006801:Humans; D019272:Leukocyte Elastase / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D010741:Phospholipases A / Q000037:antagonists & inhibitors / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000502:physiology*; D054507:Receptors, Phospholipase A2; D048051:p38 Mitogen-Activated Protein Kinases
D002614:Chelating Agents; D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; C516360:PLA2R1 protein, human; D011956:Receptors, Cell Surface; D054507:Receptors, Phospholipase A2; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D010741:Phospholipases A; D054500:Group IB Phospholipases A2; D054501:Group II Phospholipases A2; C516202:PLA2G1B protein, human; D019272:Leukocyte Elastase; D002118:Calcium