CD4+ T helper cells, especially Th17 cells, combined with immune regulatory network dysfunction, play key roles in autoimmune diseases including multiple sclerosis (MS). Betulinic acid (BA), a natural pentacyclic triterpenoid, has been reported to be involved in anti-inflammation, in particular having an inhibitory effect on pro-inflammatory cytokine IL-17 and IFN-γ production. In this study, we screened BA derivatives and found a BA derivative, SH479, which had a greater inhibitory effect on Th17 differentiation. Our further analysis showed that SH479 had a greater inhibitory effect on Th17 and Th1, and a more stimulatory effect on Tregs. To evaluate the effects of SH479 on autoimmune diseases in vivo, we employed the extensively used MS mouse model experimental autoimmune encephalomyelitis (EAE). Our results showed that SH479 ameliorated clinical and histological signs of EAE in both prevention and therapeutic protocols by regulating the Th17/Treg balance. SH479 dose-dependently reduced splenic lymphocyte pro-inflammatory factors and increased anti-inflammatory factors. Moreover, SH479 specifically inhibited splenic lymphocyte viability from EAE mice but not normal splenic lymphocyte viability. At the molecular level, SH479 inhibited Th17 differentiation by regulating STAT3 phosphorylation, DNA binding activity, and recruitment to the Il-17a promoter in CD4+ T cells. Furthermore, SH479 promoted the STAT5 signaling pathway and inhibited the NF-κB signaling pathway. Together, our data demonstrated that SH479 ameliorated EAE by regulating the Th17/Treg balance through inhibiting the STAT3 and NF-κB pathways while activating the STAT5 pathway, suggesting that SH479 is a potential novel drug candidate for autoimmune diseases including multiple sclerosis.
- The American Society for Pharmacology and Experimental Therapeutics