Exosomes And CTHRC1 Promote Wound Repair And Regulated By TBC1D3

Background: The healing of acute wounds is vital to humans and is a well-orchestrated process that involves systemic and local factors.However,there is a lack of effective and safe clinical therapies.Exosomes represent a ubiquitous mechanism of cell-cell communication that is critically important to inflammation,cancer,infection,immune tolerance and privilege,arthritis and wound healing.The collagen triple helix repeat containing 1(CTHRC1)protein is a type of exocrine protein that has been recently reported to contribute to tissue repair.TBC1D3 is a human-unique gene and reported to regulate the release of EVs.Objective: Our aim is:(1)to validate the promoting effects of EVs and its payload CTHRC1 on the healing of acute wounds and to elucidate the underlying molecular mechanism;(2)to explore the regulation effect and the mechanism of TBC1D3 on EVs release.Methods: We first established acute wound mouse models,polyvinylalcohol(PVA)sponge implants,to simulate the internal environment of wound healing and adopted it as the factory of wound-derived EVs,and then we collected the EVs from the PVA implants and analysed them.We testify the function and safety of recombinant CTHRC1 and collected EVs in vitro then evaluated the effect of CTHRC1 and woundderived EVs' accelerating the healing process of acute wounds.After that,we used mass spectrometry,flow cytometry,western blotting and real-time PCR to investigate the molecular mechanism.At last,we adopted lentivirus and adoptive transfer to elucidate the regulation and the mechanism of TBC1D3 on release of EVs.Results: PVA model is a reliable source of wound-derived EVs.Wound-derived EVs contain CTHRC1 and increasing factors normally associated with EV biogenesis and membrane dynamics.We found that CTHRC1 increased the M2 macrophage population and the TGF-? expression level as a result of the activation of the TGF-? and Notch pathways,which eventually contributed to the promotion of wound healing.Inhibition of the Notch pathway showed attenuated M2 macrophage recruitment,and it decreased the TGF-? expression level.Adoptive transfer of TBC1D3 retarded the wound healing in vivo and decrease the phosphorylation of STAT3.Conclusion: Wound-derived EVs accelerate wound closure;CTHRC1 promotes wound healing by recruiting M2 macrophages and regulating the TGF-? and Notch pathways;The release and the payload of EVs is regulated by TBC1D3.