Search Results

Objective To clarify whether the regulatory effect of all-trans-retinoic acid (atRA) on the antigen presentation function of dendritic cell(DC) is tightly associated with NF-κB signaling pathway.Also to clarify atRA mainly affected differentiated DC or influence the differentiation procedure from bone marrow cell to DC.Methods MOG35-55 immunized C57BL/6J mice received administration of atRA or not,splenic DC and CD4 cells isolated from immunized mice were subjected to in vitro cross-culture,treated with IL-12 and IL-23 respectively.Th1 and Th17 polarization of stimulated CD4 cells were determined by intracellular staining and FACS analysis,while the production of their corresponding cytokines,IFN-γ and IL-17,were measured by ELISA.Bone marrow cells were isolated from the femurs of the na(i)ve mice,treated with IL-4 and GM-CSF with or without synergistic RA treatment.MHC Ⅱ and CD11c molecules on the DC were assayed by immune staining and FACS analysis,their antigen presentation functions were decided by the proliferation and cytokine production of the Th1 effecter cells stimulated by antigen pulsed DC.To investigate the status of the NF-κB signaling pathway,the amount of phospho-Ser536 NF-κB p65 in the whole DC lysate and total NF-κB p65 in the nucleus were detected by Western blot.Finally,selective RA receptor antagonists were studied to figure out which receptor was majorly involved in the regulatory effect of RA on DC.Results Splenic DC from RA treated mice showed significantly decreased function of presenting antigen to stimulate CD4 cell polarization and cytokine production.Compared with untreated control,RA in vitro treated DC showed decreased expression of MHC Ⅱ and CD11c on its cell surface,which was accompanied with depressed function of stimulating Th1 cell proliferation and IFN-γ production.Further study revealed that RA mainly affect the differentiation procedure from BMC to DC,however,has no significant effect on differentiated DC as the aspects of MHC Ⅱ,CD11c expression,responder cell proliferation and cytokine production were evaluated.Decreased amount of phosphor-Ser536 NF-κB p65 in the whole cell lysate and total NF-κB p65 in the nucleus was investigated in RA treated DC,and decreased antigen presentation function of RA treated DC always came together with diminished activation of NF-κB signaling pathway.Finally it was demonstrated that RARβγ antagonist,but not RARα antagonist,could entirely block the RA effect on DC.Conclusion Retinoic acid inhibit the differentiation of DC as well as decrease its antigen presentation function,which might be resulted from the inactivation of NF-κB p65 signaling pathway and mediated by RARβγ.