Figure 8. A proposed model for hucMSC-ex-specific 14-3-3ζ confer protection against UV-induced acute photodamage. hucMSC-ex play an important role of cytoprotection through inhibit oxidative stress and inflammatory, reduce UV-induced DNA damage, and promote autophagy activation in vivo and in vitro. Mechanically, the 14-3-3ζ proteins were carried by hucMSC-ex are responsible for up-regulation of SIRT1 expression.