Lysophosphatidylcholine increases neutrophil bactericidal activity by enhancement of azurophil granule-phagosome fusion via glycine.GlyR alpha 2/TRPM2/p38 MAPK signaling.
Neutrophils are the first-line defense against microbes. Enhancing the microbicidal activity of neutrophils could complement direct antimicrobial therapy for controlling intractable microbial infections. Previously, we reported that lysophosphatidylcholine (LPC), an endogenous lipid, enhances neutrophil bactericidal activity (Yan et al. 2004. Nat. Med. 10: 161-167). In this study we show that LPC enhancement of neutrophil bactericidal activity is dependent on glycine, and is mediated by translocation of intracellularly located glycine receptor (GlyR) alpha2 to the plasma membrane, and subsequent increase in azurophil granule-phagosome fusion/elastase release. LPC induced GlyRalpha2-mediated [Cl(-)](i) increase, leading to transient receptor potential melastatin (TRPM)2-mediated Ca(2+) influx. Studies using human embryonic kidney 293 cells heterologously expressing TRPM2 and neutrophils showed that TRPM2 channel activity is sensitive to [Cl(-)](i). Finally, LPC induced p38 MAPK phosphorylation in an extracellular calcium/glycine dependent manner. SB203580, a p38 MAPK inhibitor, blocked LPC-induced enhancement in Lucifer yellow uptake, azurophil granule-phagosome fusion, and bactericidal activity. These results propose that enhancement of azurophil granule-phagosome fusion via GlyRalpha2/TRPM2/p38 MAPK signaling is a novel target for enhancement of neutrophil bactericidal activity.
Hong
Chang-Won
CW
Department of Pharmacology, Institute of Natural Medicine, Infectious Diseases Medical Research Center and.
Kim
Taek-Keun
TK
Ham
Hwa-Yong
HY
Nam
Ju-Suk
JS
Kim
Yong Ho
YH
Zheng
Haifeng
H
Pang
Bo
B
Min
Tae-Kwon
TK
Jung
Jun-Sub
JS
Lee
Si-Nae
SN
Cho
Hyun-Jeong
HJ
Kim
Ee-Jin
EJ
Hong
In-Hwan
IH
Kang
Tae-Cheon
TC
Lee
Jongho
J
Oh
Seog Bae
SB
Jung
Sung Jun
SJ
Kim
Sung Joon
SJ
Song
Dong-Keun
DK
D000818:Animals; D001399:Azure Stains; D001770:Blood Bactericidal Activity / Q000276:immunology*; D002460:Cell Line; D003594:Cytoplasmic Granules / Q000378:metabolism; D005998:Glycine / Q000502:physiology; D006801:Humans; D019272:Leukocyte Elastase / Q000378:metabolism / Q000502:physiology; D008244:Lysophosphatidylcholines / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000276:immunology*; D008297:Male; D008561:Membrane Fusion / Q000276:immunology*; D051379:Mice; D008813:Mice, Inbred ICR; D018375:Neutrophil Activation / Q000276:immunology*; D009504:Neutrophils / Q000201:enzymology / Q000378:metabolism / Q000382:microbiology; D010588:Phagosomes / Q000378:metabolism*; D021122:Protein Subunits / Q000502:physiology; D018009:Receptors, Glycine / Q000037:antagonists & inhibitors / Q000502:physiology*; D050053:TRPM Cation Channels / Q000502:physiology*; D015854:Up-Regulation / Q000276:immunology; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology*
D001399:Azure Stains; C439504:GLRA2 protein, human; D008244:Lysophosphatidylcholines; D021122:Protein Subunits; D018009:Receptors, Glycine; D050053:TRPM Cation Channels; C121934:TRPM2 protein, human; D048051:p38 Mitogen-Activated Protein Kinases; D019272:Leukocyte Elastase; D005998:Glycine