19 research outputs found
Smoking decreases the response of human lung macrophages to double-stranded RNA by reducing TLR3 expression
Abstract
Background
Cigarette smoking is associated with increased frequency and duration of viral respiratory infections, but the underlying mechanisms are incompletely defined. We investigated whether smoking reduces expression by human lung macrophages (Mø) of receptors for viral nucleic acids and, if so, the effect on CXCL10 production.
Methods
We collected alveolar macrophages (AMø) by bronchoalveolar lavage of radiographically-normal lungs of subjects undergoing bronchoscopies for solitary nodules (n = 16) and of volunteers who were current or former smokers (n = 7) or never-smokers (n = 13). We measured expression of mRNA transcripts for viral nucleic acid receptors by real-time PCR in those AMø and in the human Mø cell line THP-1 following phorbol myristate acetate/vitamin D3 differentiation and exposure to cigarette smoke extract, and determined TLR3 protein expression using flow cytometry and immunohistochemistry. We also used flow cytometry to examine TLR3 expression in total lung Mø from subjects undergoing clinically-indicated lung resections (n = 25). Of these, seven had normal FEV1 and FEV1/FVC ratio (three former smokers, four current smokers); the remaining 18 subjects (14 former smokers; four current smokers) had COPD of GOLD stages I-IV. We measured AMø production of CXCL10 in response to stimulation with the dsRNA analogue poly(I:C) using Luminex assay.
Results
Relative to AMø of never-smokers, AMø of smokers demonstrated reduced protein expression of TLR3 and decreased mRNA for TLR3 but not TLR7, TLR8, TLR9, RIG-I, MDA-5 or PKR. Identical changes in TLR3 gene expression were induced in differentiated THP-1 cells exposed to cigarette smoke-extract in vitro for 4 hours. Among total lung Mø, the percentage of TLR3-positive cells correlated inversely with active smoking but not with COPD diagnosis, FEV1% predicted, sex, age or pack-years. Compared to AMø of never-smokers, poly(I:C)-stimulated production of CXCL10 was significantly reduced in AMø of smokers.
Conclusions
Active smoking, independent of COPD stage or smoking duration, reduces both the percent of human lung Mø expressing TLR3, and dsRNA-induced CXCL10 production, without altering other endosomal or cytoplasmic receptors for microbial nucleic acids. This effect provides one possible mechanism for increased frequency and duration of viral lower respiratory tract infections in smokers.
Trial registration
ClinicalTrials.gov
NCT00281190
,
NCT00281203
and
NCT00281229
.http://deepblue.lib.umich.edu/bitstream/2027.42/134585/1/12931_2012_Article_1336.pd
Smoking decreases the response of human lung macrophages to double-stranded RNA by reducing TLR3 expression
Complex Adaptive Systems of Systems (CASoS) Engineering and Foundations for Global Design
Approved for public release; further dissemination unlimited
Comparing current fitness center members’ perceptions of the motivational climate with non-members
Lung Dendritic Cell Expression of Maturation Molecules Increases with Worsening Chronic Obstructive Pulmonary Disease
Rationale: Dendritic cells (DCs) have not been well studied in chronic obstructive pulmonary disease (COPD), yet their integral role in activating and differentiating T cells makes them potential participants in COPD pathogenesis
IL-18 or IL-15 Disease Severity and with In Vitro Stimulation by Increases with Chronic Obstructive Pulmonary T Cells + Cytotoxic Potential of Lung CD8 References
Cytotoxic potential of lung CD8+ T cells increases with COPD severity and with in vitro stimulation with IL-18 or IL-15
Lung CD8+ T cells might contribute to progression of chronic obstructive pulmonary disease (COPD) indirectly via IFN-gamma
production or directly via cytolysis, but evidence for either mechanism is largely circumstantial. To gain insights into these
potential mechanisms, we analyzed clinically indicated lung resections from three human cohorts, correlating findings with
spirometrically defined disease severity. Expression by lung CD8+ T cells of IL-18R and CD69 correlated with severity, as did
mRNA transcripts for perforin and granzyme B, but not Fas ligand. These correlations persisted after correction for age, smoking
history, presence of lung cancer, recent respiratory infection, or inhaled corticosteroid use. Analysis of transcripts for killer cell
lectin-like receptor G1, IL-7R, and CD57 implied that lung CD8+ T cells in COPD do not belong to the terminally differentiated
effector populations associated with chronic infections or extreme age. In vitro stimulation of lung CD8+ T cells with IL-18 plus
IL-12 markedly increased production of IFN-gamma and TNF-alpha, whereas IL-15 stimulation induced increased intracellular perforin
expression. Both IL-15 and IL-18 protein expression could be measured in whole lung tissue homogenates, but neither correlated
in concentration with spirometric severity. Although lung CD8+ T cell expression of mRNA for both T-box transcription factor
expressed in T cells and GATA-binding protein 3 (but not retinoic acid receptor-related orphan receptor gamma or alpha) increased with
spirometric severity, stimulation of lung CD8+ T cells via CD3epsilon-induced secretion of IFN-gamma, TNF-alpha, and GM-CSF, but not IL-5,
IL-13, and IL-17A. These findings suggest that the production of proinflammatory cytokines and cytotoxic molecules by lungresident
CD8+ T cells contributes to COPD pathogenesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91952/1/2010 Journal of Immunology Cytotoxic potential of lung CD8+ T cells increases with COPD severity and with in vitro stimulation with IL-18 or IL-15.pd