title: Effects of cigarette smoke on Toll-like receptor (TLR) activation of chronic obstructive pulmonary disease (COPD) macrophages.
abstract: Chronic obstructive pulmonary disease (COPD) is characterized by an abnormal innate immune response. We have investigated the changes in the innate immune response of COPD alveolar macrophages exposed to both cigarette smoke and Toll-like receptor (TLR) stimulation. COPD and control alveolar macrophages were exposed to cigarette smoke extract (CSE) followed by TLR-2, -4 and -5 ligands [Pam3CSK4, lipopolysaccharide (LPS) and phase I flagellin (FliC), respectively] or non-typeable Haemophilus influenzae (NTHi). CSE exposure suppressed TLR-induced tumour necrosis factor (TNF)-α, interleukin (IL)-6, IL-10 and regulated on activation, normal T cell expressed and secreted (RANTES) production in both COPD and control alveolar macrophages, but had no effect on interleukin 8 (CXCL8) production. Similarly, CSE suppressed NTHi-induced TNF-α but not NTHi-induced CXCL8 production in COPD alveolar macrophages. Gene expression analysis showed that CSE suppressed LPS-induced TNF-α transcription but not CXCL8 transcription in COPD alveolar macrophages. The dampening effect of CSE on LPS-induced cytokine production was associated with a reduction in p38, extracellular signal regulated kinase (ERK) and p65 activation. In conclusion, CSE caused a reduced innate immune response in COPD alveolar macrophages, with the exception of persistent CXCL8 production. This could be a mechanism by which alveolar macrophages promote neutrophil chemotaxis under conditions of oxidative stress and bacterial exposure.
authors: The University of Manchester, Manchester Academic Health Science Centre, University Hospital South Manchester NHS Foundation Trust, NIHR South Manchester Respiratory and Allergy Clinical Research Facility, Manchester, UK.
authors: H J
authors: HJ
authors: Metcalfe
authors: S
authors: S
authors: Lea
authors: D
authors: D
authors: Hughes
authors: R
authors: R
authors: Khalaf
authors: K
authors: K
authors: Abbott-Banner
authors: D
authors: D
authors: Singh
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D005786:Gene Expression Regulation; D006192:Haemophilus Infections / Q000276:immunology / Q000382:microbiology; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism; D008262:Macrophage Activation / Q000276:immunology; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism*; D016676:Macrophages, Alveolar / Q000276:immunology / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000209:etiology* / Q000503:physiopathology; D012907:Smoking / Q000009:adverse effects*; D051193:Toll-Like Receptors / Q000235:genetics / Q000378:metabolism*; D051996:Transcription Factor RelA / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D016207:Cytokines; D016209:Interleukin-8; D051193:Toll-Like Receptors; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases
keywords: COPD macrophage; TLR; bacteria; cigarette smoke; immune response