## 5 Conclusions  
Our study shows that _Iris_-exosomes have antioxidant and anti-senescence properties. _Iris_-exosomes also possess the potential to reduce oxidative stress and cellular dysfunction caused by H\({}_{2}\)O\({}_{2}\). As shown in Figure 7, _Iris_-exosomes upregulate the levels of antioxidant enzymes, such as _HO_-_I_, _CAT_, _GSS_, _GPx1_, and _SOD_, which, in turn, regulate intracellular ROS levels. Moreover, _Iris_-exosomes mitigate oxidative stress induced by H\({}_{2}\)O\({}_{2}\), leading to enhanced wound-healing activity and normal differentiation in skin cells. _Iris_-exosomes also regulate the p38/JNK MAPK pathway to reduce the levels of p53 and p21, thereby effectively inhibiting cellular senescence. These results may lead to improved skin health and antiaging effects. _Iris_-exosomes also regulate differentiation markers and accelerate the re-epithelialization of wounds. Therefore, further investigation via human clinical trials is required in order to verify the efficacy of these methods in facilitating skin regeneration.  
**Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app132111681/s1](https://www.mdpi.com/article/10.3390/app132111681/s1)]([https://www.mdpi.com/article/10.3390/app132111681/s1](https://www.mdpi.com/article/10.3390/app132111681/s1)), Figure S1: Protective effect of Iris-exosome on cell viability against H\({}_{2}\)O\({}_{2}\)-induced cytotoxicity in human dermal fibroblast (nHDFs). (a) Cell viabilities pretreated with Iris-exosomes for 24 h and examined by WST-1 assay. (b) Cell viability of nHDFs with H\({}_{2}\)O\({}_{2}\) for 24 h. (c) nHDFs were treated with 300 uM H\({}_{2}\)O\({}_{2}\) for 24 h after Iris-exosomes for 24 h and cell viability was measured by MTT assay. Values are expressed as mean\(\pm\)SD of three independent experiments. \"\"_p_ < 0.01 and \"\"_p_ < 0.001 compared with untreated cells; \"\"_p_ < 0.001 compared with H\({}_{2}\)O\({}_{2}\)-treated cells.  
**Author Contributions:** Conceptualization, J.-S.K., H.-J.L., H.L., Y.J., Y.K., S.-J.P., J.K. and S.B.; methodology, J.-S.K., H.-J.L. and S.B.; software, J.-S.K. and H.-J.L.; validation, J.-S.K., H.-J.L. and S.B.; formal analysis, [PERSON]-S.K., H.-J.L., E.-J.Y., H.L., Y.J. and Y.K.; investigation, [PERSON]-S.K., H.-J.L. and E.-J.Y.; resources, [PERSON]-S.K., H.L., S.-J.P. and S.B.; data curation, [PERSON]-S.K., [PERSON]-J.L. and S.B.; writing--original draft preparation, J.-S.K. and S.B.; writing--review and editing, J.-S.K., Y.J., Y.K., J.K. and S.B.; visualization, J.-S.K. and S.B.; supervision, S.B.; project administration, S.B.; funding acquisition, S.B. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was supported by the development of new products subject to purchase conditions (S3303942) funded by the Ministry of SMEs and Startups (MSS, Korea).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Not applicable.  
**Acknowledgments:** The authors are grateful to the Department of Cosmetics Engineering, Konkuk University, for supporting the use of their research facilities.  
**Conflicts of Interest:** The authors declare no conflict of interest.  
Figure 7: In nHEKs, ROS produced by H\({}_{2}\)O\({}_{2}\) activate the intrinsic pathway of oxidative stress. The _Iris_-exosomes increase the levels of antioxidant enzymes, such as _HO-1_, _CAT_, _GSS_, _GPx1_, and _SOD_, which regulate the levels of intracellular ROS. Furthermore, increased wound-healing activity and normal differentiation of skin cells are associated with _Iris_-exosome treatment, which mitigates oxidative stress induced by H\({}_{2}\)O\({}_{2}\). Additionally, _Iris_-exosomes inhibit cellular senescence via modulating the p38/JNK MAPK pathway, resulting in reducing the levels of p53 and p21.