Dopaminergic stimulation leads B-cell infiltration into the central nervous system upon autoimmunity

Abstract

\n Multiple sclerosis (MS) involves a CD4+ T-cell-driven autoimmune response to central nervous system (CNS) derived antigens. Previous evidence has suggested that B-cells play a fundamental role as antigen-presenting cells (APC) in mouse models of MS re-stimulating CD4+ T-cells in the CNS as well as regulating the T-cell response by mean of inflammatory or anti-inflammatory cytokines. Despite an important dopaminergic regulation of T-cells has been previously described in MS, the effects of dopaminergic signalling in B-cells in this pathology remains unexplored. Here we addressed the role of the dopamine receptor D3 (DRD3), which display the highest affinity for dopamine, in B-cells in animal models of MS. Experimental autoimmune encephalomyelitis (EAE) was induced in mice harbouring Drd3-deficient or Drd3-suficient B-cells. Our data shows that, by promoting the expression of the chemokine receptor CXCR3 in autoreactive B-cells, DRD3-stimulation favours the CNS-tropism in a subset of B-cells that act as APC in the CNS, which is fundamental for disease development. Furthermore, we found that DRD3-stimulation induced the expression of the CNS-homing molecule CD49d in a B-cell subset with anti-inflammatory features, thus attenuating EAE manifestation in a CNS-autoimmunity model independent of the APC function of B-cells. Our findings demonstrate that DRD3-stimulation in B-cells exerts a dual role in CNS-autoimmunity, favouring CNS-tropism of pro-inflammatory B-cells with APC function, and also promoting CNS-homing of B-cells with anti-inflammatory features. Thus, these results show DRD3-stimulation in B-cells as a key regulator of CNS-autoimmunity.