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Sci Rep. 2016 Oct 5;6:34560. doi: 10.1038/srep34560.

Leukotriene B4 receptor type 2 protects against pneumolysin-dependent acute lung injury.

Author information

1
Department of Biochemistry, Juntendo University School of Medicine, Tokyo, Japan.
2
Department of Anesthesiology and Critical Care Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
3
Department of Respiratory Medicine, Juntendo University School of Medicine, Tokyo, Japan.
4
Research Institute for Diseases of the Chest, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
5
Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.
6
Lipid Signaling Project, National Center for Global Health and Medicine, Tokyo, Japan.
7
Department of Biochemistry, University of Geneva, Geneva, Switzerland.
8
Center for Inflammation, Immunity and Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA.

Abstract

Although pneumococcal infection is a serious problem worldwide and has a high mortality rate, the molecular mechanisms underlying the lethality caused by pneumococcus remain elusive. Here, we show that BLT2, a G protein-coupled receptor for leukotriene B4 and 12(S)-hydroxyheptadecatrienoic acid (12-HHT), protects mice from lung injury caused by a pneumococcal toxin, pneumolysin (PLY). Intratracheal injection of PLY caused lethal acute lung injury (ALI) in BLT2-deficient mice, with evident vascular leakage and bronchoconstriction. Large amounts of cysteinyl leukotrienes (cysLTs), classically known as a slow reactive substance of anaphylaxis, were detected in PLY-treated lungs. PLY-dependent vascular leakage, bronchoconstriction, and death were markedly ameliorated by treatment with a CysLT1 receptor antagonist. Upon stimulation by PLY, mast cells produced cysLTs that activated CysLT1 expressed in vascular endothelial cells and bronchial smooth muscle cells, leading to lethal vascular leakage and bronchoconstriction. Treatment of mice with aspirin or loxoprofen inhibited the production of 12-HHT and increased the sensitivity toward PLY, which was also ameliorated by the CysLT1 antagonist. Thus, the present study identifies the molecular mechanism underlying PLY-dependent ALI and suggests the possible use of CysLT1 antagonists as a therapeutic tool to protect against ALI caused by pneumococcal infection.

PMID:
27703200
PMCID:
PMC5050523
DOI:
10.1038/srep34560
[Indexed for MEDLINE]
Free PMC Article

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