Human airway smooth muscle cells express eotaxin in response to signaling following mast cell contact
ABSTRACT Asthma is a chronic inflammatory disease of the airways. Mast-cell (MC)-derived cytokines may mediate both airway inflammation and remodeling. It has also been shown that airway smooth muscle cells (ASMC) can be a source of proinflammatory cytokines. In the human airways, MC-ASMC cell interactions may have pivotal effects on modulating inflammation.
We wanted to know whether the production of eotaxin, an important proinflammatory cytokine, through a cell-to-cell contact mechanism of human ASMC activation by MC was mediated by p38 MAPK.
We cocultured normal humanASMC with a human MC line (HMC-1) and assayed for the production of eotaxin.
When cultured together, human ASMC and HMC-1 contact induced eotaxin secretion. Separation of HMC-1 and human ASMC by a porous membrane inhibited this induction. Coculturing of human ASMC with HMC-1 induced increased expression of eotaxin gene mRNA. HMC-1-derived cellular membranes caused an increase in eotaxin production in human ASMC. Activation of p38 MAPK was also seen in cocultures by Western blot, whereas eotaxin production in cocultures was significantly inhibited by the p38 inhibitor SB203580.
These novel studies reveal the importance of cell-to-cell interactions in the complex milieu of airway inflammation.
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ABSTRACT: Abstract Background: Mast cell infiltration into airway smooth muscle (ASM) bundle is an important feature of asthma. Extracellular adenosine triphosphate (eATP) contributes to the initiation of airway inflammation. eATP induces mast cells migration by acting through purinergic receptors. CD39 is an ectonucleotidase that degrades ATP to ADP and AMP. Whether eATP participates in the migration of mast cell towards ASM cells is still unknown. Methods: ASMCs were isolated from C57/BL6J mice sensitized and challenged with OVA. ASMCs were in vitro cultured and stimulated with IL-4+IL-13 in the presence or absence of exogenous CD39 or CD39 inhibitor ARL67156. ATP level in the supernatants was measured with ATP content determination kit. CXCL10 concentration in the ASMCs supernatants was measured by ELISA, the mRNA expression of CXCL10 in ASMCs was determined with real-time PCR. Human mast cell line HMC-1 was cultured in Iscove's Modified Dubecco's Medium. The expression of CXCR3 in HMC-1 cells was determined with flow cytometry and real-time PCR respectively. HMC-1 migration rates were determined with transwell system. Results: In the supernatants of Th2 cytokine-stimulated ASMCs, ATP level was higher than that without stimulation. CD39 decreased, whereas ARL67156 increased ATP level in the supernatants. Both ATP and the supernatants of Th2 cytokine-stimulated ASMCs induced migration of HMC-1 cells. The surface and mRNA expression of CXCR3 in HMC-1 cells, and the mRNA expression and secretion of CXCL10 in ASMCs were increased after stimulation with ATP or Th2 cytokines. All these effects were partially inhibited by CD39. Conclusion: Our data suggested ASMCs in the asthma microenvironment promoted the migration of mast cells via secretion of ATP and the expression of CXCL10/CXCR3 axis. CD39 could reverse this effect and may be a new target for the treatment of asthma.Journal of Asthma 10/2014; DOI:10.3109/02770903.2014.939283 · 1.83 Impact Factor
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ABSTRACT: Background: A notable feature of allergic asthma is the infiltration of mast cells into smooth muscle in the human airway. Thus, mast cells and human airway smooth muscle (hASM) cells are likely to exhibit mutual functional modulation via direct cell-cell contact or through released factors. This study examined mast cell modulation of hASM cell cytokine release. Methods: The mast cell line HMCα was used to model mast cell function. hASM cells were either co-cultured directly with resting or IgE/antigen-stimulated HMCα cells or treated with HMCα-conditioned media to examine the impact on cytokine release. The activation pathways triggered in hASM cells by the mast cell-derived factors were examined through the use of selective inhibitors and by Western blotting. Results: HMCα cells, or their conditioned media, induced the expression of cytokines (IL-8 and IL-6) by hASM cells at both the mRNA and the protein level. Cytokine expression in hASM cells was greatly amplified when HMCα cells were IgE/antigen-activated. The effects of the conditioned media were not mediated by the chemokines MCP-1 and MIP-1α or by exosomes. While the mast cell-derived factor(s) increased p38(MAPK) phosphorylation in hASM cells, cytokine production was not inhibited by the p38(MAPK) inhibitor SB203580. hASM cell production of IL-8 induced by HMCα condition media but not IL-6 was, however, attenuated by the Src tyrosine kinase inhibitor PP2. Conclusions: Our study shows that the release of soluble mediators by activated mast cells can stimulate hASM cells to elicit production of proinflammatory cytokines that may then exacerbate airway inflammation in asthma.International Archives of Allergy and Immunology 09/2012; 160(1):75-85. DOI:10.1159/000339697 · 2.43 Impact Factor