C C chemokine receptor 5 antagonist alleviates inflammation by regulating IFN-γ/IL-10 and STAT4/Smad3 signaling in a mouse model of autoimmune encephalomyelitis

Multiple sclerosis (MS) is an immunopathological disease that causes demyelination and recurrent episodes of T cell-mediated immune attack in the central nervous system. Experimental autoimmune encephalomyelitis (EAE) is a well-established mouse model of MS. The roles of T cells in MS/EAE have been well investigated, but little is known about the role of CCR5+ cells. In the present study, we investigated whether treatment with DAPTA, a selective CCR5 antagonist, could modulate the progression of EAE in the SJL/J mice. EAE mice were treated with DAPTA (0.01 mg/kg) intraperitoneally daily from day 14 to day 42, and the clinical scores were evaluated. We further investigated the effects of DAPTA on IFN-γ-, TGF-β-, IL-10-, IL-17A-, IL-22-, T-bet, STAT4-, RORγT-, AhR-, Smad3-, and Foxp3-expressing CCR5+ spleen cells using flow cytometry analysis. We further explored the effects of DAPTA on mRNA/protein expression of IFN-γ, IL-10, IL-17A, IL-22, TGF-β, T-bet, STAT4, RORγT, AhR, Foxp3, and NF-H in the brain tissue. The severity of clinical scores decreased in DAPTA-treated EAE mice as compared to that in the EAE control mice. Moreover, the percentage of CCR5+IFN-γ+, CCR5+T-bet+, CCR5+STAT4+, CCR5+IL-17A+, CCR5+RORγt+, CCR5+IL-22+, and CCR5+AhR+ cells decreased while CCR5+TGF-β+, CCR5+IL-10+, CCR5+Smad3+, and CCR5+Foxp3+ increased in DAPTA-treated EAE mice. Furthermore, DAPTA treatment significantly mitigated the EAE-induced expression of T-bet, STAT4, IL-17A, RORγT, IL-22, and AhR but upregulated Foxp3, IL-10, and NF-H expression in the brain tissue. Taken together, our data demonstrated that DAPTA could ameliorate EAE progression through the downregulation of the inflammation-related cytokines and transcription factors signaling, which may be useful for the clinical therapy of MS.