Epithelium-derived chemokines induce airway smooth muscle cell migration.
ABSTRACT The remodelling of airway smooth muscle (ASM) associated with asthma severity may involve the migration of ASM cells towards the epithelium. However, little is known about the mechanisms of cell migration and the effect of epithelial-derived mediators on this process.
The main objective of the current study is to assess the effects of epithelial-derived chemokines on ASM cell migration.
Normal human ASM cells were incubated with supernatants from cells of the bronchial epithelial cell line BEAS-2B and normal human bronchial epithelial (NHBE) cells. To induce chemokine production, epithelial cells were treated with TNF-alpha. Chemokine expression by epithelial cells was evaluated by quantitative real-time PCR, ELISA and membrane antibody array. To identify the role of individual chemokines in ASM cell migration, we performed migration assays with a modified Boyden chamber using specific neutralizing antibodies to block chemokine effects.
Supernatants from BEAS-2B cells treated with TNF-alpha increased ASM cell migration; migration was increased 1.6 and 2.5-fold by supernatant from BEAS-2B cells treated with 10 and 100 ng/mL TNF-alpha, respectively. Protein levels in supernatants and mRNA expression by BEAS-2B cells of regulated on activation, normal T cell expressed and secreted (RANTES) and IL-8 were significantly increased by 100 ng/mL TNF-alpha treatment. The incubation of supernatant with antibodies to RANTES or IL-8 significantly reduced ASM cell migration, and the combined antibodies further inhibited the cell migration. The migratory effects of supernatants and inhibiting effects of RANTES and/or IL-8 were confirmed also using NHBE cells.
The results show that chemokines from airway epithelial cells cause ASM cell migration and might potentially play a role in the process of airway remodelling in asthma.
- SourceAvailable from: Laila Al-Alwan[show abstract] [hide abstract]
ABSTRACT: Airway smooth muscle cell (ASMC) migration is one of the proposed mechanisms underlying the increased airway smooth muscle mass seen in airway remodeling of patients with severe asthma. IL-17-related cytokines are a new subgroup of inflammatory mediators that have been suggested to play a role in regulating smooth muscle function. We hypothesized that IL-17-induced chemokine production from smooth muscle cells can contribute to migration of additional smooth muscle cells in the airways of asthmatic patients. We sought to investigate the effect of IL-17 on smooth muscle-derived chemokines and to examine the mechanisms involved in their production and contribution to the increase in airway smooth muscle migration. The effect of IL-17-induced supernatants on human ASMC migration was investigated. IL-17-induced growth-related oncogene (GRO) production and mRNA expression was assessed by using ELISA and RT-PCR, respectively. The direct effect of GROs on ASMC migration and the involvement of the CXCR2 receptor were also examined. IL-17-induced supernatants promoted ASMC migration. After IL-17 stimulation, GROs were the most abundant chemokines produced from ASMCs, and blocking their effect by using neutralizing antibodies significantly inhibited ASMC migration. In addition, a combination of recombinant human GRO-α, GRO-β, and GRO-γ was able to promote significant migration of ASMCs that was mediated through the CXCR2 receptor. These findings suggest that IL-17-induced GROs can be an important mediator of ASMC migration and therefore might contribute to the pathogenesis of airway remodeling in asthmatic patients.The Journal of allergy and clinical immunology 06/2012; 130(4):977-985.e6. · 9.17 Impact Factor
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ABSTRACT: Rhinovirus (RV) infections cause exacerbations and development of severe asthma highlighting the importance of antiviral interferon (IFN) defence by airway cells. Little is known about bronchial smooth muscle cell (BSMC) production of IFNs and whether BSMCs have dsRNA-sensing receptors besides TLR3. dsRNA is a rhinoviral replication intermediate and necrotic cell effect mimic that mediates innate immune responses in bronchial epithelial cells. We have explored dsRNA-evoked IFN-β and IFN-λ1 production in human BSMCs and potential involvement of TLR3 and RIG-I-like receptors (RLRs). Primary BSMCs were stimulated with 0.1-10 µg/ml dsRNA, 0.1-1 µg/ml dsRNA in complex with the transfection agent LyoVec (dsRNA/LyoVec; selectively activating cytosolic RLRs) or infected with 0.05-0.5 MOI RV1B. Both dsRNA stimuli evoked early (3 h), concentration-dependent IFN-β and IFN-λ1 mRNA expression, which with dsRNA/LyoVec was much greater, and with dsRNA was much less, after 24 h. The effects were inhibited by dexamethasone. Further, dsRNA and dsRNA/LyoVec concentration-dependently upregulated RIG-I and MDA5 mRNA and protein. dsRNA and particularly dsRNA/LyoVec caused IFN-β and IFN-λ1 protein production (24 h). dsRNA- but not dsRNA/LyoVec-induced IFN expression was partly inhibited by chloroquine that suppresses endosomal TLR3 activation. RV1B dose-dependently increased BSMC expression of RIG-I, MDA5, IFN-β, and IFN-λ1 mRNA. We suggest that BSMCs express functional RLRs and that both RLRs and TLR3 are involved in viral stimulus-induced BSMC expression of IFN-β and IFN-λ1.PLoS ONE 01/2013; 8(4):e62718. · 3.73 Impact Factor
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ABSTRACT: Smooth muscle comprises a key functional component of both the airways and their supporting vasculature. Dysfunction of smooth muscle contributes to and exacerbates a host of breathing-associated pathologies such as asthma, chronic obstructive pulmonary disease and pulmonary hypertension. These diseases may be marked by airway and/or vascular smooth muscle hypertrophy, proliferation and hyper-reactivity, and related conditions such as fibrosis and extracellular matrix remodeling. This review will focus on the contribution of airway or vascular smooth dysfunction to common airway diseases.Pulmonary Pharmacology & Therapeutics 04/2012; · 2.54 Impact Factor