Effects of exosomes derived from adipose mesenchymal stem cells on the regulation of dendritic epidermal T cells and wound inflammation in mice

DING Hongfan; XU Xiao; CHEN Minliang; ZHOU Guiwen; FU Qiang; WANG Yichen; BAI Ruiqi

doi:10.3969/j.issn.1673-7040.2024.06.013

Abstract：Objective To investigate the impact of exosomes derived from adipose tissue mesenchymal stem cells(ADSCs-exo)on dendritic epidermal T cells(DETC)and inflammation in cutaneous wounds of mice.Method From January to December 2023,ADSCs were isolated using the type Ⅰ collagenase digestion method,while ADSCs-exo were obtained through differential ultracentrifugation.DETCs were extracted and cultured in primary culture,with cell purity confirmed by flow cytometry.An inflammation model of DETC cells was established in vitro using cleaved soybean protein A(ConA),and the mRNA expressions of IL-2 and IL-17A in cells were analyzed by RT-qPCR.A full-thickness skin defect wound model was created on the back skin of C57 mice,which were then divided into a blank con-trol group,a PBS injection group,and an ADSCs-exo injection group.The levels of IL-17A,Akt,and P-Akt at the wound edge were as-sessed by Western blotting.The expression of DETCs at the wound edge was observed via flow cytometry.Results In the DETC in vitro inflammation model,the mRNA expressions of IL-2 and IL-17A were significantly elevated in the ConA group compared to the Control group.However,in the ConA+ADSCs-exo groups,there was a noticeable decrease in mRNA expressions of IL-2 and IL-17A when com-pared to the ConA group.During the mouse wound healing process,lower levels of IL-17A content were detected at the skin edge of wounds treated with ADSCs-exo compared to those treated with PBS or left untreated(control).Additionally,higher expression levels of P-Akt were observed at these sites as well.On day one after acute trauma,both PBS and ADSCs-exo treatments resulted in significantly increased migration and enrichment degree of DETC cells at wound edges compared to control samples.By day three post-injury,while DETC expression remained significantly higher for PBS-treated wounds relative to controls;its expression decreased within ADSCs-ex-o-treated wounds and reached similar levels as seen in control samples.Conclusion ConA can stimulate activated DETC to secrete IL-17A and IL-2,whereas ADSCs-exo significantly suppress the expression of IL-2 and IL-17A.During the process of wound healing in mice,ADSCs-exo inhibit the expression of IL-17A while promoting P-Akt expression.The expression of DETC at the wound site can be upregulated in response to acute trauma;although ADSCs-exo do not exhibit obvious chemotactic enrichment effect on DETC,the inhibition of DETC expression effectively impedes the occurrence of persistent and excessive inflammatory reactions in the wound,thereby ensuring a more controlled and regulated healing process.