Adenosine A2A receptor-mediated interactions between Th1+ T cells and the choroid plexus epithelium via IFN-γ signalling control T-Cell infiltration in experimental autoimmune encephalomyelitis

Abstract

Abstract Background Adenosine A2A receptor (A2AR) antagonists have been consistently demonstrated to protect against multiple sclerosis (MS) pathology, but A2AR knockout (A2AR−/−) mice exhibit exacerbated immune injury, raising concerns regarding the use of A2AR antagonists for MS treatment. Here, we revealed the critical involvement of A2AR-mediated interactions between Th1+ T cells and the choroid plexus (ChP) epithelium in the pathology of experimental autoimmune encephalomyelitis (EAE). Methods We assessed the effects of A2AR knockout on ChP gateway activity and the interferon gamma (IFN-γ)-secreting capacity of Th1+ T cells in an EAE model by immunofluorescence, qPCR and flow cytometry (FCM). We also investigated the effects of A2AR-mediated interactions between Th1+ T cells and the ChP epithelium on ChP gateway activity in vivo via intracerebroventricular (ICV) injection of Th1+ T cells and in vitro via coculture of ChP epithelial cells and splenic Th1+ T cells. We further knocked down IFN-γ receptor 1 (IFNGR1) specifically in the ChP of A2AR−/− mice via ICV injection of AAV2/5-shRNA (IFNGR1) to disrupt the interactions between Th1+ T cells and the ChP epithelium and thus assess the roles of these interactions in the development of EAE pathology. Results A2AR knockout disrupted the ChP barrier and increased T-cell infiltration across the ChP in EAE model mice. Coculture of splenic Th1+ T cells and ChP epithelial cells revealed that A2AR knockout in ChP epithelial cells strengthened the ChP barrier and attenuated T-cell migration, whereas A2AR knockout in Th1+ T cells increased the accumulation of Th1+ T cells in the ChP via the secretion of IFN-γ. Consistent with the coculture results, ICV injection of activated splenic Th1+ T cells from A2AR−/− mice increased the accumulation of T cells in the ChP to a greater extent than did injection of Th1+ T cells from A2AR+/+ mice. This effect was due to the increased secretion of IFN-γ in A2AR−/− mice compared with A2AR+/+ mice. Finally, ChP-specific knockdown of IFNGR1 attenuated A2AR knockout-induced T-cell infiltration, brain inflammation and EAE pathology. Conclusion A2AR-mediated interactions between Th1+ T cells and the ChP epithelium via the secretion of IFN-γ from CD4+ T cells and the binding IFN-γ to IFNGR1 in the ChP epithelium control immune cell invasion and the development of EAE pathology in A2AR−/− mice.

Keywords

• Multiple sclerosis
• Experimental autoimmune encephalomyelitis
• Adenosine A2A receptor
• Choroid plexus
• CD4+ T cells