Figure 8: NAD⁺ regulates CD4⁺ T-cell differentiation through Tph1.

(a) Behavioural scores of EAE in wild-type C57BL/6 mice treated either with intraperitoneal injection of 60 mg of NAD⁺ or a placebo solution (PBS). An additional group of mice was treated with intraperitoneal injections of NAD⁺ and p-chlorophenylalanin (Tph1 inhibitor). As a control group, wild-type mice were treated with Tph1 inhibitor alone (n=5 per group). (b) CD4⁺ T cells were isolated from spleens 13 days after EAE induction and CD4⁺ frequencies of CD25⁺Foxp3⁺, IL-17A⁺, IFNγ⁺ and IFNγ⁺IL-10⁺ cells were analysed by flow cytometry. (c) Behavioural scores of EAE in wild-type mice (C57BL/6 background) treated at days 3, 6 and 9 with intravenous injections of sorted naïve CD4⁺CD25⁺CD44^lowCD62L^high T cells (2 × 10⁶ cells) that were cultured during 4 days in Th1 polarizing conditions in the presence of NAD⁺ (250 μM) or a placebo solution (PBS). As control groups, wild-type mice were subjected to EAE and treated with NAD⁺ (60 mg) or PBS intravenously at days 3, 6 and 9 (n=8–11 per group). Data derived from two independent experiments; data represent mean±s.d. *P<0.05; **P<0.01; ***P<0.001 significant as determined by Student’s t-test and Mann–Whitney U-test were used accordingly to compare between groups. i.p., intraperitoneal; i.v. intravenous.