Airway Smooth Muscle Cells Promote HMC-1Cells Chemotaxis Through ATP And CXCL10/CXCR3Axis In Asthma

Background Mast cell infiltration into airway smooth muscle (ASM) bundle is one of major pathological features of asthma. Larger increases in Extracellular adenosine triphosphate (eATP) as a key danger signal in inflammatory processes. Studies now point to roles for eATP in asthmatic airway inflammation by activating dendritic cells. However, the roles of eATP through HMC-1cells in asthma have not been investigated before.Objective In the present study, we hypothesized that Th2cytokine activated ASMCs may secret more eATP which promoted the migration of mast cells towards eATP concentration gradient.Methods The mice ASMCs cultured in vitro were incubated with IL-4and IL-13. The supernatants were collected for testing HMC-1chemotaxis with transwell assay. The level of eATP was measured using ATP Content determination kit, the concentration of CXCL10in cultural supernatants of ASMCs was measured with ELISA. The mRNA expression of CXCL10in ASMCs and CXCR3, CXCR4in HMC-1cells were determined with real-time PCR.Results ATP concentration was higher in supernatants of ASMCs stimulated by IL-4and IL-13than that of control group. The ectonucleotase CD39decreased the ATP concentrations, whereas the ATPase inhibitor ARL67156increased it. ATP at10μM induced obvious migration, this effect was inhibited by CD39. Interestingly, the supernatants of ASMCs stimulated by IL-4and IL-13were able to induce HMC-1chemotaxis, which was inhibited by CD39. Both ATP and supernatants of ASMCs stimulated by IL-4and IL-13increased the expression of CXCR3. The expression of CXCL10, ligand for CXCR3in ASMCs was increased after stimulation with ATP. Similarly, CD39decreased this effect.Conclusion Th2cytokines stimulated ASMCs have an increased secretion of ATP, which then promotes the migration of HMC-1. ATP also increased the expression of CXCR.3in HMC-1and the secretion of CXCL10of AMSC cells. These effects of ATP are inhibited by CD39. Thus, CD39may be of great importance in inhibiting the infiltration of mast cells into ASM bundle by metabolizing the excessive eATP.