Silencing of topical proline hydroxylase domain 2 promotes the healing of rat diabetic wounds by phosphorylating AMPK.

BACKGROUND: For diabetic ulcers, the impaired response to hypoxia is a key feature associated with delayed healing. In the early phase of hypoxia, hypoxic signaling activates the AMPK system through direct phosphorylation of the PHD2 pathway, producing a significant endogenous hypoxic protective effect. METHODS: Twenty Sprague-Dawley (SD) rats were randomly divided into two groups: treatment (sh-PHD2) and control (sh-Control). Using lentiviral encapsulation of PHD2-shRNA and transfection, the silencing efficiency of PHD2 expression was verified in rat dermal fibroblasts (RDF) and in rat aortic endothelial cells (RAECs). Changes in the ability of RDF and RAECs to proliferate, migrate, and in the rate of ATP production were observed and then tested after inhibition of AMPK phosphorylation using dorsomorphin. The lentiviral preparation was injected directly into the wounds of rats and wound healing was recorded periodically to calculate the healing rate. Wounded tissues were excised after 14 days and the efficiency of PHD2 silencing, as well as the expression of growth factors, was examined using molecular biology methods. Histological examination was performed to assess CD31 expression and therefore determine effects on angiogenesis. RESULTS: Lentiviral-encapsulated PHD2-sh-RNA effectively suppressed PHD2 expression and improved the proliferation, migration, and ATP production rate of RDF and RAEC, which were restored to their previous levels after inhibition of AMPK. The rate of wound healing, vascular growth, and expression of growth factors were significantly improved in diabetic-model rats after local silencing of PHD2 expression. CONCLUSION: Silencing of PHD2 promoted wound healing in diabetic-model SD rats by activating AMPK phosphorylation.

Direct-current electric field stimulation promotes proliferation and maintains stemness of mesenchymal stem cells.

Mesenchymal stem cells are frequently utilized in the study of regenerative medicine. Electric fields (EFs) influence many biological processes, such as cell proliferation, migration and differentiation. In the present study, a novel device capable of delivering a direct current of EF stimulation to cells cultured in vitro is described. This bioreactor was customized to simultaneously apply a direct-current EF to six individual cell culture wells, which reduces the amount of experimental time and minimizes cost. In testing the device, adipose-derived mesenchymal stem cells stimulated with an EF in the bioreactor exhibited a greater cell proliferation rate while retaining stemness. The results provide a unique perspective on adipose-derived mesenchymal stem cell proliferation, which is needed for tissue engineering and regenerative medicine.

Hypoxia activates the PI3K/AKT/HIF-1α pathway to promote the anti-inflammatory effect of adipose mesenchymal stem cells.

This study aimed to investigate the effect of hypoxia on the anti-inflammatory effect of adipose-derived mesenchymal stem cells (AMSCs) in vitro and its possible mechanism. AMSCs were cultured in vitro in a hypoxic environment with 3% O2, and a normoxic (21% O2) environment was used as the control. The cells were identified by in vitro adipogenic and osteogenic differentiation and cell surface antigen detection, and the cell viability were detected. The effect of hypoxic AMSCs on macrophage inflammation was analyzed by co-culture. The results showed that under hypoxia, AMSCs had better viability, significantly downregulated the expression of inflammatory factors, alleviated macrophage inflammation, and activated the PI3K/AKT/HIF-1α pathway.