The emerging field of regenerative medicine has revealed that the exosome contributes to many aspects of development and disease through intercellular communication between donor and recipient cells. However, the biological functions of exosomes secreted from cells have remained largely unexplored. Here, we report that the human hepatic progenitor cells (CdHs)‐derived exosome (EXO hCdHs ) plays a crucial role in maintaining cell viability. The inhibition of exosome secretion treatment with GW4869 results in the acceleration of reactive oxygen species (ROS) production, thereby causing a decrease of cell viability. This event provokes inhibition of caspase dependent cell death signaling, leading to a ROS‐dependent cell damage response and thus induces promotion of antioxidant gene expression or repair of cell death of hypoxia‐exposed cells. Together, these findings show the effect of exosomes in regeneration of liver cells, and offer valuable new insights into liver regeneration.

Recent research has revealed that exosomes affect several aspects of organism physiology and development, as well as disease processes, through intracellular communication. However, the biological roles of exosomes in exosomesecreting cells have remained largely unexplored. In this study, we demonstrate that Schwann cell (SC)-derived exosomes (EXO SC ) promote cell survival among motor neurons (MNs), with MN viability exceeding 80% at days in vitro (DIV) 14. Prevention of MN cell death by EXO SC was achieved by blocking the caspase-3 cell death pathway, which was confirmed by comparing the number of activated-caspase3 + cells according to the presence versus absence of EXO SC . The attenuation of exosome secretion from SCs by treatment with GW4869 resulted in increased MN cell death, regardless of SC viability. Together, these findings enhance our understanding of exosome biology and provide valuable new insights into exosomes as a potential therapeutic agent in nervous system disorders.

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