New insight into the role of exosomes in vitiligo

Exosomes are nanosized extracellular vesicles that originate from endosomes and are secreted by most cells into the extracellular space. They serve as mediators of intercellular communication and have been implicated in the regulation of several physiological and pathological processes. Vitiligo is a depigmentation skin disease caused by progressive destruction of autologous epidermal melanocytes. Autoimmune intolerance is one of the leading theories proposed for melanocyte destruction in vitiligo via CD8⁺, regulatory T (Treg) and T helper 17 (Th17) cell imbalance in adaptive immunity. In this review, we investigate the association of exosomes with vitiligo and emphasize the role of exosomes in immune regulation, melanocyte-keratinocyte interactions, and melanogenesis. The exosomal pathway is necessary for the regulation of CD8⁺, Treg and Th17 cells in both pathological and physiological conditions. Exosomes derived under pathological conditions can influence CD8⁺, Treg and Th17 cell balance in the disease microenvironment, which may contribute to disruption of autoimmune tolerance in vitiligo. In addition, exosomes serve as mediators of communication between keratinocytes and melanocytes in the melanogenesis pathway and may also be involved in melanosome transport. They also regulate melanocyte survival and the protein expression of enzymes such as tyrosinase (TYR), tyrosinase-related protein 1 (TYRP1), tyrosinase-related protein-2 (TYRP2) and microphthalmia-associated transcription factor (MITF) in melanogenesis, which suggests that melanin production is associated with exosomes. An improved understanding of the role of exosomes in immune regulation and melanogenesis may help to elucidate the pathogenesis of vitiligo and lead to the development of potential diagnostic markers and therapeutic options.