Fig 2: Dopamine in the inflamed colon. Abbreviations: CCR9: C-C chemokine receptor type 9; DA: dopamine; D3R, D5R: dopamine receptors; DβH: dopamine β-hydroxylase; IBD: inflammatory bowel disease; LPMCs: lamina propria mononuclear cells; NA: noradrenaline; TH: tyrosine hydroxylase.

Fig 3: Drd3 deficiency in B cell abrogates disease manifestation in an EAE model that depends on the APC-function of B cells. BM chimeric mice harbouring Drd3-deficient (grey symbols) or Drd3-sufficient (black symbols) B cells were generated as described in Fig. 2A. Next, EAE was induced in chimeric mice by immunization with huMOG in CFA followed by pertussis toxin injection. A Disease severity was evaluated throughout the time-course of the disease development. Values represent the mean ± SEM; n = 4 mice per group. B–D At the peak of disease severity (day 15 post-induction), mononuclear cells were isolated from the CNS (B and C) and the spleen (D) followed by ex vivo stimulation with PMA/ionomycin in the presence of brefeldin A, and intracellular cytokine staining analysis in CD4+ Tcells was carried out by flow cytometry. B Representative dot-plots in the CD4+ gate are shown. Numbers indicate the percentage of cells in the corresponding quadrant. C, D Quantification of the frequency of CD4+ T cells producing IFNγ, IL-17, GM-CSF or expressing FoxP3. n = 3–4 mice per group. Each symbol represents data obtained from an individual mouse. The mean ± SEM are depicted. Data representative from one out of two independent experiments are shown. *, p < 0.05; **, p < 0.01; ****, p < 0.0001 by Mann–Whitney U test (A) or two-way ANOVA followed by Sidak’s post hoc test (C, D)

Fig 4: DRD3 deficiency results in unresponsiveness of astrocytes upon systemic LPS treatment. Wild-type (WT) or DRD3 knockout (DRD3KO) mice received an i.p. injection of LPS (5 mg/kg) or PBS. After 3 h, mice were sacrificed, and astrogliosis was analysed by immunohistochemical analysis of GFAP in the striatum. a Representative overview images at low magnification are shown (bar, 100 μm). b Quantification of GFAP immunoreactivity density. Data from five to six mice per group is shown. Values are the mean ± SEM. *p < 0.05 by two-way ANOVA followed by Sidak’s post-hoc test

Fig 5: DRD3-signalling in lymphocytes is required for the development of CNS autoimmunity. A BM chimeric mice harbouring Drd3-deficient or Drd3-sufficient lymphocytes were generated by the i.v. transfer of a 4:1 mixed BM from Rag1−/− and Drd3−/− mice (grey symbols) or 4:1 mixed BM from Rag1−/− and Drd3+/+ mice (white symbols), respectively, into γ-irradiated Rag1−/− recipient mice. Afterwards, EAE was induced in chimeric mice by immunization with pMOG35-55 in CFA followed by pertussis toxin injection and disease severity was determined throughout the time-course of the disease development. n = 4–5 mice per group. Top panel shows an illustration of the experimental strategy for generation of chimeric mice. Bottom panel shows the quantification of clinical score for different experimental groups. (B) Primary progressive EAE was induced in mice bearing Drd3-deficient (grey symbols) or Drd3-sufficient (white symbols) CD4+ T cells by the i.v. transfer of transgenic naïve CD4+ T cells (Tn; 7.5 × 105 cells per mouse) isolated from Drd3−/− 2D2 or Drd3+/+ 2D2 mice into Rag1−/− recipient mice. Disease severity was determined throughout the time-course of the disease development. n = 4 mice per group. Top panel illustrates the experimental design to induce primary-progressive EAE. Bottom panel shows the quantification of clinical score for different experimental groups. C EAE was induced in wild-type C57BL/6 mice by immunization with pMOG35-55 (black symbols) or huMOG (grey symbols) in CFA followed by pertussis toxin injection. Disease severity was evaluated throughout the time-course of the disease development. n = 6–8 mice per group. D, E At the peak of disease severity (indicated by an arrow in C), mononuclear cells were isolated from the spleen, draining lymph nodes (dLN) and central nervous system (CNS) and the frequency of CD19+ B cells from the CD45+ gate (D) and the percentage of DRD3 expression in CD19+ B cells (E) were evaluated. A control group (white symbols) without immunization (-) was included in the analysis. D, E n = 3–9 mice per group. A–E Each symbol represents data obtained from an individual mouse. The mean ± SEM are depicted. *, p < 0.05; **, p < 0.01; ****, p < 0.0001 by Mann–Whitney U test (A–C) or one-way ANOVA followed by Tukey’s post hoc t-test (D, E)