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National Institute of Environmental Health Sciences

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Your Environment. Your Health.

Publication Detail

Title: Protection against inhaled oxidants through scavenging of oxidized lipids by macrophage receptors MARCO and SR-AI/II.

Authors: Dahl, Morten; Bauer, Alison K; Arredouani, Mohamed; Soininen, Raija; Tryggvason, Karl; Kleeberger, Steven R; Kobzik, Lester

Published In J Clin Invest, (2007 Mar)

Abstract: Alveolar macrophages (AMs) express the class A scavenger receptors (SRAs) macrophage receptor with collagenous structure (MARCO) and scavenger receptor AI/II (SRA-I/II), which recognize oxidized lipids and provide innate defense against inhaled pathogens and particles. Increased MARCO expression in lungs of ozone-resistant mice suggested an additional role protecting against inhaled oxidants. After ozone exposure, MARCO-/- mice showed greater lung injury than did MARCO+/+ mice. Ozone is known to generate oxidized, proinflammatory lipids in lung lining fluid, such as 5beta,6beta-epoxycholesterol (beta-epoxide) and 1-palmitoyl-2-(9'-oxo-nonanoyl)-glycerophosphocholine (PON-GPC). Intratracheal instillation of either lipid caused substantial neutrophil influx in MARCO-/- mice, but had no effect in MARCO+/+ mice. Normal AMs showed greater uptake in vitro of beta-epoxide compared with MARCO-/- AMs, consistent with SRA function in binding oxidized lipids. SR-AI/II-/- mice showed similar enhanced acute lung inflammation after beta-epoxide or another inhaled oxidant (aerosolized leachate of residual oil fly ash). In contrast, subacute ozone exposure did not enhance inflammation in SR-AI/II-/- versus SR-AI/II+/+ mice, reflecting increased AM expression of MARCO. These data identify what we believe to be a novel function for AM SRAs in decreasing pulmonary inflammation after oxidant inhalation by scavenging proinflammatory oxidized lipids from lung lining fluids.

PubMed ID: 17332894 Exiting the NIEHS site

MeSH Terms: No MeSH terms associated with this publication

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