Kaempferide promotes melanogenesis through miR-145-associated glutathione depletion with partial ROS contribution

Despite the pathological link between vitiligo and both oxidative stress and melanin dysregulation, reactive oxygen species (ROS)-modulating therapies show limited efficacy. Kaempferide, a compound from Vernonia anthelmintica (L.) Willd, promotes glutathione (GSH)-dependent melanogenesis, yet its mechanism of action in vitiligo treatment remains to be fully elucidated.

This study aimed to elucidate whether kaempferide-induced melanogenesis is associated with GSH depletion and the underlying regulatory mechanism.

B16F10 cells, primary melanocytes from C57BL/6 J mice, and zebrafish larval models were used to investigate the role of GSH/thiol homeostasis in kaempferide-induced melanogenesis using biochemical, fluorescence-based, transcriptomic, miR-145-5p mimic transfection, and connectivity-mapping approaches.

Kaempferide increased melanogenesis in cells and zebrafish and reduced intracellular thiol/GSH levels, accompanied by an increase in ROS. Further, it also reduced the expression of GSH-metabolic genes and proteins. NAC attenuated, whereas BSO potentiated, kaempferide-induced melanogenic responses, supporting GSH depletion as a major biochemical event. Transcriptomic analysis showed decreased miR-145 and increased Mest expression, and miR-145-5p mimic attenuated both kaempferide-induced melanogenesis and the accompanying reduction in thiol/GSH levels. CMap analysis further provided hypothesis-generating associations between kaempferide-responsive signatures and miR-145-associated regulatory networks.

Kaempferide-induced melanogenesis is a GSH-dependent process with miR-145-associated regulation whereas ROS contributes partially and appears to act in a secondary manner.