Extracellular Vesicles Derived from Adipose-Derived Stem Cells Facilitate Frostbite Wound Healing By Regulating SOCS3 Expression

Background: Though adipose-derived stem cells (ADSCs) have potential applications for the repair and regeneration of damaged tissues, limited studies have defined the function of ADSCs on dermal fibroblasts. Our RNA-seq sequencing identified differentially expressed SOCS3 in frostbite injury. Objective: In the current study, we aim to examine the hypothesis that extracellular vesicles derived from adipose-derived mesenchymal stem cells (ADSCs-EVs) may modulate SOCS3/TGF-β1 signaling in wound healing of frostbite injury. Methods: sh-SOCS3 and sh-TGF-β1 were introduced to explore the biological role of SOCS3 in frostbite injury by detecting the proliferation and migration of human skin fibroblast (HSF) cells and the wound healing in mice. Furthermore, the extracted ADSCs-EVs were interfered with HSF cells in vitro or injected into the frostbitten mouse model in vivo. Results: Upregulation of SOCS3 occurred in the skin tissues of frostbitten mice. Compared to sh-NC, the wound healing rate of sh-SOCS3 presented higher on day 7(31.34±4.35 vs 41.83±3.74, p < 0.05) and day 14 (63.42±6.01 vs 88.99±5.12, p < 0.05) after injury. Silencing SOCS3 can promote frostbite wound healing. Moreover, SOCS3 downregulated TGF-β1 to suppress the proliferation and migration of HSF cells, thus impeding the skin wound healing. Additionally, ADSCs-EVs could enhance the proliferation and migration of HSF cells according to the results of CCK-8 assay (p < 0.05), scratch test (17.82±4.25 vs 49.78±2.54, p < 0.05) and Transwell assay (42.33±6.81 vs 91.33±7.02, p < 0.05), and regulate the expression of SOCS3/TGF-β1. The role of ADSCs-EVs in frostbite wound healing was also confirmed in vivo. ADSCs-EVs could promote frostbite wound healing by downregulating the expression of SOCS3 and upregulating the expression of TGF-β1 and collagen I. Conclusions: Collectively, ADSCs-EVs inhibit SOCS3 and facilitate the expression of TGF-β1, which promotes the proliferation and migration of HSF cells and subsequently enhances wound healing of frostbite injury.