L-Cysteine promotes the proliferation and differentiation of neural stem cells via the CBS/H₂S pathway.

Growing evidence has suggested that hydrogen sulfide (H₂S) acts as a novel neuro-modulator and neuroprotective agent; however, it remains to be investigated whether H2S has a direct effect on neural stem cells (NSCs). We report here that NSCs expressed cystathionine β synthase (CBS) and addition of exogenous H2S donor, L-cysteine, stimulated proliferation and increased the differentiation potential of NSCs to neurons and astroglia. Moreover, pre-treatment with aminooxyacetic acid, the inhibitor of CBS or knockdown of CBS in using siRNA, significantly attenuated the effects of L-cysteine on elevated H₂S levels and the cell proliferation; it also effectively suppressed L-cysteine-induced neurogenesis and astrocytogenesis. Further analysis revealed that L-cysteine-induced proliferation was associated with phosphorylation of extracellular signal-regulated kinases 1/2 and differentiation with altered expression of differentiation-related genes. Taken together, the present data suggest that L-cysteine can enhance proliferation and differentiation of NSCs via the CBS/H2S pathway, which may serve as a useful inference for elucidating its role in regulating the fate of NSCs in physiological and pathological settings.