HIF1alpha overexpression enhances diabetic wound closure in high glucose and low oxygen conditions by promoting adipose-derived stem cell paracrine function and survival.

BACKGROUND: Adipose-derived stem cell (ADSC) transplantation is a promising strategy to promote wound healing because of the paracrine function of stem cells. However, glucose-associated effects on stem cell paracrine function and survival contribute to impaired wound closure in patients with diabetes, limiting the efficacy of ADSC transplantation. Hypoxia-inducible factor (HIF)1alpha plays important roles in wound healing, and in this study, we investigated the effects of HIF1alpha overexpression on ADSCs in high glucose and low oxygen conditions. METHODS: Adipose samples were obtained from BALB/C mice, and ADSCs were cultured in vitro by digestion. Control and HIF1alpha-overexpressing ADSCs were induced by transduction. The mRNA and protein levels of angiogenic growth factors in control and HIF1alpha-overexpressing ADSCs under high glucose and low oxygen conditions were analyzed by quantitative reverse transcription-polymerase chain reaction and western blotting. The effects of ADSC HIF1alpha overexpression on the proliferation and migration of mouse aortic endothelial cells (MAECs) under high glucose were evaluated using an in vitro coculture model. Intracellular reactive oxygen species (ROS) and 8-hydroxydeoxyguanosine (8-OHdG) levels in ADSCs were observed using 2,7-dichlorodihydrofluorescein diacetate staining and enzyme-linked immunosorbent assays, respectively. Apoptosis and cell cycle analysis assays were performed by flow cytometry. An in vivo full-thickness skin defect mouse model was used to evaluate the effects of transplanted ADSCs on diabetic wound closure. RESULTS: In vitro, HIF1alpha overexpression in ADSCs significantly increased the expression of vascular endothelial growth factor A, fibroblast growth factor 2, and C-X-C motif chemokine ligand 12, which were inhibited by high glucose. HIF1alpha overexpression in ADSCs alleviated high glucose-induced defects in MAEC proliferation and migration and significantly suppressed ADSC ROS and 8-OHdG levels, thereby decreasing apoptosis and enhancing survival. In vivo, HIF1alpha overexpression in ADSCs prior to transplantation significantly enhanced angiogenic growth factor expression, promoting wound closure in diabetic mice. CONCLUSIONS: HIF1alpha overexpression in ADSCs efficiently alleviates high glucose-induced paracrine dysfunction, decreases oxidative stress and subsequent DNA damage, improves viability, and enhances the therapeutic effects of ADSCs on diabetic wound healing.