Adipose mesenchymal stem cell-derived extracellular vesicles regulate PINK1/parkin-mediated mitophagy to repair high glucose-induced dermal fibroblast senescence and promote wound healing in rats with diabetic foot ulcer.

Abstract

Aims: Diabetic foot ulcers (DFUs) cause prominent morbidity and mortality. Adipose mesenchymal stem cell (ASC)-derived extracellular vesicles (EVs) show property in facilitating diabetic wound healing, and we explored their role in DFU rats.

Methods: ASCs were cultured in vitro, passaged and then identified by flow cytometry and induction of osteogenic/adipogenic differentiation. ASC-EVs were extracted and identified. DFU rat model was treated with ASC-EVs. High glucose (HG)-induced rat dermal fibroblasts were treated with ASC-EVs or 3-MA and sh-PINK1 plasmid in vitro. Wound healing was observed. Histological changes, inflammatory cytokines (TNF-α, IL-1β), and α-SMA and p21 double-positive cell level were assessed by HE staining, ELISA, and immunofluorescence. Mitochondrial membrane potential (MMP), cell viability and senescence, and ROS production in cells were assessed by fluorescence dye JC-1, CCK-8, SA-β-gal staining, and ROS kit. p21, LC3II/I, p62, PINK1 and parkin protein levels were determined by Western blot.

Results: DFU rats had slow wound healing and elevated levels of IL-1β, TNF-α, α-SMA and p21 double-positive cells, and SA-β-gal, while HG-induced cells had weakened viability, elevated ROS, SA-β-gal, p21 and p62 protein levels, and decreased LC3II/I, PINK1 and parkin protein levels and MMP, which were reversed by ASC-EVs. HG inhibited mitophagy by suppressing the PINK1/parkin pathway to accelerate dermal fibroblast senescence. The PINK1/parkin pathway inhibition partly mitigated the effect of ASC-EVs. ASC-EVs promoted mitophagy by activating the PINK1/parkin pathway in vivo.

Conclusions: ASC-EVs mediated mitophagy by activating the PINK1/parkin pathway, thereby impeding HG-induced rat dermal fibroblast senescence and promoting wound healing in DFU rats.