Eliminating or blocking 12/15-lipoxygenase reduces neutrophil recruitment in mouse models of acute lung injury
1 Department of Anesthesiology, Intensive Care and Pain Medicine, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A1, Münster, 48149, Germany
2 Department of Internal Medicine, Eastern Virginia Medical School, P.O. Box 1980, Norfolk, VA 23501-1980, USA
3 Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA
Critical Care 2012, 16:R166 doi:10.1186/cc11518
See related commentary by Zaslona and Peters-Golden, http://ccforum.com/content/16/5/161Published: 13 September 2012
Acute lung injury (ALI) is a common disease in critically ill patients with a high morbidity and mortality. 12/15-lipoxygenase (12/15-LO) is an enzyme generating 12-hydroxy-eicosatetraenoic acid (12-HETE) and 15-HETE from arachidonic acid. It has been shown that 12/15-LO is involved in the regulation of vascular permeability during ALI.
To test whether 12/15-LO participates in leukocyte recruitment into the lung, we investigated the role of 12/15-LO in mouse models of lipopolysaccharide (LPS)-induced pulmonary inflammation and acid-induced ALI, a clinically relevant model of acute lung injury.
The increase in neutrophil recruitment following LPS inhalation was reduced in 12/15-LO-deficient (Alox15-/-) mice and in wild-type (WT) mice after the blocking of 12/15-LO with a pharmacological inhibitor. Bone marrow chimeras revealed that 12/15-LO in hematopoietic cells regulates neutrophil accumulation in the interstitial and alveolar compartments, whereas the accumulation of neutrophils in the intravascular compartment is regulated by 12/15-LO in non-hematopoietic and hematopoietic cells. Mechanistically, the increased plasma levels of the chemokine CXCL1 in Alox15-/- mice led to a reduced response of the neutrophil chemokine receptor CXCR2 to stimulation with CXCL1, which in turn abrogated neutrophil recruitment. Alox15-/- mice also showed decreased edema formation, reduced neutrophil recruitment and improved gas exchange in an acid-induced ALI model.
Our findings suggest that 12/15-LO modulates neutrophil recruitment into the lung by regulating chemokine/chemokine receptor homeostasis.