CD73+ adipose-derived stem cells reduce scar formation through PLOD1.

Abstract

BackgroundReducing cutaneous scar formation is important for assessing the success of skin wound healing. Although it is generally accepted that adipose-derived mesenchymal stem cells (AMSCs) have substantial therapeutic potential, efforts are continuously made to improve the outcome of AMSC therapy. Post-transcriptional suppression of procollagen-lysine 1, 2-oxoglutarate 5-dioxygenase 1 (PLOD1) in AMSCs has been shown to greatly reduce scar formation during skin wound healing, likely through modulating macrophage polarization. In the present study, we tested whether a CD73+ subpopulation of AMSCs could reduce scar formation compared with CD73– AMSCs.MethodsThe gene profile of CD73+ versus CD73– AMSCs was obtained from a validated public database, GSE167219. AMSCs were isolated from adipose tissue surrounding the groin of mice, after which CD73+ versus CD73– AMSCs were sorted using flow cytometry. PLOD1 levels were determined in CD73+ versus CD73– AMSCs. Then, PLOD1 in CD73– AMSCs was depleted by a short-hair interfering RNA against PLOD1 (sh-PLOD1), while PLOD1 in CD73+ AMSCs was increased by expression of a PLOD1 transgene. A blade was used to induce a skin injury on the middle back of the mice. Either CD73+ AMSCs or CD73+ PLOD1 AMSCs or CD73– AMSCs or CD73– sh-PLOD1 AMSCs were intravenously transplanted into the injured region of the mice. Fibrosis and the underlying mechanisms were investigated. Co-immunoprecipitation was performed to evaluate interaction between CD73 and PLOD1.ResultsCD73+ AMSCs expressed significantly lower levels of PLOD1, a potent stimulator of fibrosis, compared with CD73– AMSCs. Transplantation of CD73+ AMSCs generated significantly reduced fibrosis at the skin injury site compared with CD73– AMSCs. However, expression of PLOD1 in CD73+ AMSCs abolished its advantageous effects on fibrosis reduction, while depletion of PLOD1 in CD73– AMSCs improved the outcome of fibrosis to the levels of transplantation of CD73+ AMSCs. Co-immunoprecipitation showed no direct protein interaction between CD73 and PLOD1.ConclusionsCD73+ AMSCs are a subgroup of AMSCs with better therapeutic effects on wound healing, and can inhibit scar formation through reduced PLOD1 in an indirect manner.