Highly expressed adenosine receptor A2B in mucosa dendritic cells is associated with enhanced pathogenicity of Crohn's disease / 中华微生物学和免疫学杂志

ABSTRACT

Objective To investigate the expression of adenosine receptor (ADOR) subtypes (A2A and A2B subtypes) in the mucosal dendritic cells (DCs) from patients with Crohn's disease and their pathogenic roles.Methods Mucosal DCs (mDCs) were isolated from resected intestine of patients with or without Crohn's disease.Some of the mDCs were cultured in vitro and others were used to extract RNA.The expression of ador-a2a and ador-a2b were detected by real-time qPCR.mDCs in culture were treated with selective ADOR-A2A and ADOR-A2B agonists (CGS 21680 and BAY 60-6583) and then the concentration of IL-1,IL-6 and IL-12 in the medium were measured by ELISA.The binding affinities of ADOR-A2A and ADOR-A2B to adenosine were determined by 3H-adenosine in combination with selective ADOR-A2A and A2B antagonists (SCH58261 and MRS1706).Na(i)ve CD4+ cells were collected from human umbilical cord blood and co-cultured with mDCs treated by different ADOR agonists to observe T cell responses.The production of cytokines in culture was measured by ELISA.The polarization of CD4+ cells was analyzed by intracellular cytokine staining and FACs analysis.Peripheral blood mononuclear cells (PBMCs) were treated with IL-4 and GMCSF to induce the expression of monocyte-derived DCs (Mo-DCs).Mo-DCs were treated with different toll-like receptor ligands to investigate their effects on the expression of ador-a2a and adora2b.Moreover,Mo-DCs were treated with LPS and BAY 60-6583 individually or in the combination to stimulate CD4+ cells.Then the production of cytokines and the polarization of CD4+ cells were evaluated.Results Compared with patients without Crohn's disease,patients with Crohn's disease showed no change in the expression of ador-a2a but a significantly increased expression of ador-a2b in mCDs (CD-mDCs),enabling to bind more adenosines.Activated ADOR-A2B signaling pathway induced CD-mDCs to secret more proinflammatory cytokines and to promote polarization of CD4+ cells toward Th1 and Th17 cells.Toll-like receptor ligands,pam3csk4 and LPS could intensively augment the expression of ador-a2b in Mo-DCs.The pathogenicity of Mo-DCs was strengthened upon a combined stimulation with BAY 60-6583 and LPS.Conclusion The significantly increased expression of ador-a2b in mDCs might be involved in the pathogenesis of Crohn's disease by promoting mDCs to secret more pro-inflammatory cytokines and enhancing the polarization of CD4+ cells.Moreover,the expression of ador-a2b in DCs could be regulated by certain toll like receptors.