Bushfire smoke is pro-inflammatory and suppresses macrophage phagocytic function
Open Access
- 7 September 2018
- journal article
- research article
- Published by Springer Science and Business Media LLC in Scientific Reports
- Vol. 8 (1), 13424
- https://doi.org/10.1038/s41598-018-31459-6
Abstract
Bushfires are increasing in frequency and severity worldwide. Bushfire smoke contains organic/inorganic compounds including aldehydes and acrolein. We described suppressive effects of tobacco smoke on the phagocytic capacity of airway macrophages, linked to secondary necrosis of uncleared apoptotic epithelial cells, persistence of non-typeable H. influenzae (NTHi), and inflammation. We hypothesised that bushfire smoke extract (BFSE) would similarly impair macrophage function. THP-1 or monocyte-derived macrophages (MDM) were exposed to 1–10% BFSE prepared from foliage of 5 common Australian native plants (genus Acacia or Eucalyptus), or 10% cigarette smoke extract (CSE). Phagocytic recognition receptors were measured by flow cytometry; pro-inflammatory cytokines and caspase 1 by immunofluorescence or cytometric bead array; viability by LDH assay; and capsase-3/PARP by western blot. BFSE significantly decreased phagocytosis of apoptotic cells or NTHi by both THP-1 macrophages and MDM vs air control, consistent with the effects of CSE. BFSE significantly decreased MDM expression of CD36, CD44, SR-A1, CD206 and TLR-2 and increased active IL-1β, caspase-1 and secreted IL-8. BFSE dose-dependently decreased THP-1 macrophage viability (5-fold increase in LDH at 10%) and significantly increased active caspase-3. BFSE impairs macrophage function to a similar extent as CSE, highlighting the need for further research, especially in patients with pre-existing lung disease.Funding Information
- The University of Adelaide, University Professorial Research Fellowship
This publication has 49 references indexed in Scilit:
- Air pollution from bushfires and their association with hospital admissions in Sydney, Newcastle and Wollongong, Australia 1994–2007Australian and New Zealand Journal of Public Health, 2013
- Defective Lung Macrophage Function in Lung Cancer±Chronic Obstructive Pulmonary Disease (COPD/Emphysema)-Mediated by Cancer Cell Production of PGE2?PLOS ONE, 2013
- Haemophilus influenzae and the lung (Haemophilus and the lung)Clinical and Translational Medicine, 2012
- Why is particulate matter produced by wildfires toxic to lung macrophages?Toxicology and Applied Pharmacology, 2011
- Peat Bog Wildfire Smoke Exposure in Rural North Carolina Is Associated with Cardiopulmonary Emergency Department Visits Assessed through Syndromic SurveillanceEnvironmental Health Perspectives, 2011
- Defective macrophage phagocytosis of bacteria in COPDEuropean Respiratory Journal, 2009
- California Wildfires of 2008: Coarse and Fine Particulate Matter ToxicityEnvironmental Health Perspectives, 2009
- Apoptosis-inducing factor mediates poly(ADP-ribose) (PAR) polymer-induced cell deathProceedings of the National Academy of Sciences of the United States of America, 2006
- Alveolar macrophages from subjects with chronic obstructive pulmonary disease are deficient in their ability to phagocytose apoptotic airway epithelial cellsImmunology & Cell Biology, 2003
- Suppression of alveolar macrophage membrane-receptor-mediated phagocytosis by model particle-adsorbate complexes: physicochemical moderators of uptake.Environmental Health Perspectives, 1990