Dihydroartemisinin Promotes Neural Stem Cell Differentiation into Oligodendrocytes via STAT6/Chi3l3 Signaling Pathway in Microglia

Abstract

Promoting the differentiation of neural stem cells (NSCs) into oligodendrocytes is crucial for maintaining myelin integrity in demyelinating diseases, which is regulated by the microglia-mediated inflammatory milieu in the central nervous system (CNS). In this research, we aimed to investigate whether dihydroartemisinin (DHA) could promote the differentiation of C17.2 neural stem cell into oligodendrocytes by regulating microglia, and elucidate the underlying molecular mechanisms. Moreover, DHA trimer self-assembled nanoparticles (DHA3NPs) were prepared to explore the efficacy on attenuating inflammation compared to free DHA. An in vitro microglia-NSCs co-culturing model was established. The level of inflammation and the differentiation of NSCs were accessed via RT-qPCR, ELISA and western blot methods. To inhibit STAT6 activation in microglia, AS1517499 was applied. The results found that DHA effectively rebalanced BV2-mediated inflammation and specifically induced the directed differentiation of NSC cell lines into oligodendrocytes (OLs), as represented by the expression of MBP and PLP. Mechanistically, it was demonstrated that the enhanced expression of Chi3l3 induced by DHA was significantly eliminated by the blockade of STAT6, suggesting that DHA served as a booster for OLs differentiation in a STAT6-depenent manner. In addition, DHA3NPs were more effective than free DHA in attenuating microglia-mediated inflammation stimulated by lipopolysaccharide. In conclusion, DHA attenuated microglia-mediated neuroinflammation and activated the STAT6/Chi3l3 signaling pathway in microglia, inducing C17.2 differentiation into oligodendrocytes. This study reveals the molecular mechanism and the functional impact of DHA in inhibiting inflammation of CNS, and provides preliminary suggestions for the clinical treatment of inflammatory demyelinating diseases.