Epithelium-derived chemokines induce airway smooth muscle cell migration

Meakins-Christie Laboratories, McGill University, Montreal, Quebec, Canada.
Clinical & Experimental Allergy (Impact Factor: 4.77). 05/2009; 39(7):1018-26. DOI: 10.1111/j.1365-2222.2009.03238.x
Source: PubMed


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.

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    • "Interestingly, it was suggested that these bronchial structural cells could serve as an important RV replication reservoir [31]. This latter aspect would increase the possibility of infection also of the BSMCs, applying especially to asthmatic bronchi where the smooth muscle component is increased and where smooth muscle cells may grow close to the epithelial lining [36], [37]. Hence, the present demonstration of BSMC generation of IFNs suggests that these cells may contribute to host defence in bronchial RV infections. "
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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 04/2013; 8(4):e62718. DOI:10.1371/journal.pone.0062718 · 3.23 Impact Factor
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    • "It's important to underline is the role of airway smooth muscle (ASM) that in airway remodelling phase maybe induce to airflow obstruction observed in severe form of asthma [4] [5] [6] [7]. In fact it's probable that the recurrence the ASM remodelling process is linked with relationship between ASM cells and basal steam cells [8]. These details are essential to explain the significance of the review aimed and to understand the role of epithetlium in the airways. "

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