Functional Group-Dependent Induction of Astrocytogenesis and Neurogenesis by Flavone Derivatives

Neural stem cells (NSCs) differentiate into multiple cell types, including neurons, astrocytes, and oligodendrocytes, and provide an excellent platform to screen drugs against neurodegenerative diseases. Flavonoids exert a wide range of biological functions on several cell types and affect the fate of NSCs. In the present study, we investigated whether the structure-activity relationships of flavone derivatives influence NSC differentiation. As previously reported, we observed that PD98059 (2'-amino-3'-methoxy-flavone), compound 2 (3'-methoxy-flavone) induced astrocytogenesis. In the present study, we showed that compound 3 (2'-hydroxy-3'-methoxy-flavone), containing a 3'-methoxy group, and a non-bulky group at C2' and C4', induced astrocytogenesis through JAK-STAT3 signaling pathway. However, compound 1 and 7-12 without the methoxy group did not show such effects. Interestingly, the compounds 4 (2',3'-dimethoxyflavone), 5 (2'-N-phenylacetamido-3'-methoxy-flavone), and 6 (3',4'-dimethoxyflavone) containing only 3'-methoxy could not promote astrocytic differentiation, suggesting that both the methoxy groups at C3' and non-bulky group at C2' and C4' are required for the induction of astrocytogenesis. Notably, compound 6 promoted neuronal differentiation, whereas its 4'-demethoxylated analog, compound 2, repressed neurogenesis, suggesting an essential role of the methoxy group at C4' in neurogenesis. These findings revealed that subtle structural changes of flavone derivatives have pronounced effects on NSC differentiation and can guide to design and develop novel flavone chemicals targeting NSCs fate regulation.