More and more evidence advises that circular RNAs (circRNAs) function critically in regulating different disease microenvironments. Our previous study found that autotransplantation of adipose-derived mesenchymal stem cells (ADSCs) promotes diabetes wound healing. Exosomes derived in ADSCs play an important regulatory role. This study aimed to characterize if mmu_circ_0000250 played a role in ADSC-exosome-mediated full-thickness skin wound repair in diabetic rats. Endothelial progenitor cells (EPCs) were selected to study the therapeutic mechanism of exosomes in high-glucose (HG)-induced cell damage and dysfunction. Analysis and luciferase reporter assay were utilized to explore the interaction among mmu_circ_0000250, miRNA (miR)-128-3p, and sirtuin (SIRT)1. The diabetic rats were used to confirm the therapeutic effect of mmu_circ_0000250 against exosome-mediated wound healing. Exosomes containing a high concentration of mmu_circ_0000250 had a greater therapeutic effect on restoration of the function of EPCs by promotion autophagy activation under HG conditions. Expression of mmu_circ_0000250 promoted SIRT1 expression by miR-128-3p adsorption, which was confirmed via luciferase reporter assay and bioinformatics analysis. In vivo, exosomes containing a high concentration of mmu_circ_0000250 had a more therapeutic effect on wound healing when compared with wild-type exosomes from ADSCs. Immunohistochemistry and immunofluorescence detection showed that mmu_circ_0000250 increased angiopoiesis with exosome treatment in wound skin and suppressed apoptosis by autophagy activation. In conclusion, we verified that mmu_circ_0000250 enhanced the therapeutic effect of ADSC-exosomes to promote wound healing in diabetes by absorption of miR-128-3p and upregulation of SIRT1. Therefore, these findings advocate targeting the mmu_circ_0000250/miR-128-3p/SIRT1 axis as a candidate therapeutic option for diabetic ulcers.

Diabetes mellitus is a major cause of blindness and chronic ulcers in the working age population worldwide. Former research have found that differentially expressed circular RNAs (circRNAs) are associated with hyperglycemia (HG)-induced endothelial cell damage. And adipose-derived stem cells (ADSCs)-exosome transplant have more therapeutic effect to enhance wound healing in diabetic mice by delivery circRNA. The current investigation employed high-throughput sequencing to identify circRNAs that are abnormally expressed in endothelial progenitor cells (EPCs) under HG conditions. The regulatory mechanism and predicted targets of one differentially expressed circRNA, circ-Snhg11, were investigated utilizing bioinformatics analyses, luciferase reporter assays, angiogenic differentiation assays, flow cytometric apoptosis analysis, and RT-qPCR. The result show that circ-Snhg11 expression decreased in EPCs under HG conditions and that overexpression of circ-Snhg11 suppressed HG-induced endothelial cell damage and M1-like macrophage polarization. miR-144-3p and HIF-1α were identified as downstream targets of circ-Snhg11, which was further verified by luciferase reporter analysis. miR-144-3p overexpression or HIF-1α inhibition reversed circ-Snhg11 protective effect on HG-induced endothelial cell dysfunction, as evidenced by increased apoptosis, abnormal vascular differentiation, and secretion of inflammatory factors. In addition, miR-144-3p overexpression or inhibition of HIF-1α reversed protective effect regarding circ-Snhg11 on M2-like macrophage polarization under HG conditions. These findings suggest that circ-Snhg11 promotes HIF-1α expression through miR-144-3p sponging. Our data demonstrate that circ-Snhg11 overexpression exosome from ADSCs suppresses HG-induced endothelial cell damage and induces M2-like macrophage polarization via the miR-144-3p/HIF-1α axis.

Diabetic foot ulcer (DFU) is one of diabetic complications, which is frequently present and tormented in diabetes mellitus. Most multipotent mesenchymal stromal cells (MSCs) are capable of immune evasion, providing an allogeneic, ready-to-use, cell product option for therapeutic applications. The beneficial effect of MSCs for the treatment of a variety of traumatic injuries, such as open wounds, has been extensively explored. In this study, a rat DFU model was used to simulate the pathophysiology of clinical patients and to investigate the localization of human umbilical cord mesenchymal stem cells (hUC-MSCs) after intravenous transplantation and its role in DFU healing, so as to evaluate the potential of hUC-MSCs in the treatment of DFU. The diabetic rat model was established by streptozotocin injection, which was used to create full-thickness foot dorsal skin wounds to mimic DFU by a 6-mm skin biopsy punch and a Westcott scissor. The hUC-MSCs were transplanted through femoral vein, and the ulcer cicatrization situation and the fate of hUC-MSCs were evaluated. Our data suggest that intravenously transplantated hUC-MSCs have the ability to migrate and locate to the wound tissue and are helpful to wound healing in DFU rats, partly by regulating inflammation, trans-differentiation and providing growth factors that promote angiogenesis, cell proliferation and collagen deposition. Herein, we demonstrate that hUC-MSC transplantation is able to accelerate DFU healing in rats and transplantation of exogenous stem cells may be a potential strategy for clinical application in DFUs.

Diabetic foot ulcer (DFU) is a serious diabetes complication, significantly impacting the quality of life, particularly in the elderly. Age-associated DFUs pose additional challenges due to impaired healing mechanisms. Our study aims to explore the role of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) as a miR-142 sponge in repairing diabetic rat foot ulcer tissue under age-associated diabetes, offering a new theoretical basis and therapeutic target for preventing and treating diabetic vascular disease in the elderly. Using qPCR, we analyzed MALAT1 and miR-142 expression in EPCs and hUC-MSCs. Targetscan predicted potential interaction targets for MALAT1 and miR-142, confirmed by dual luciferase reporter gene assay. An age-associated diabetic rat model was established using Streptozotocin (STZ) injection. Hypoxia, apoptosis, and angiogenesis-related proteins were assessed through Western Blot. In vitro, miR-142 inhibition and MALAT1 overexpression promoted foot ulcer healing in diabetic rats. MALAT1 acted as a miR-142 sponge, downregulated in hUC-MSCs under high glucose, relevant to age-associated diabetic foot ulcers. MiR-142 negatively regulated SIRT1 and Nrf2. In vitro experiments demonstrated potential significance for age-related DFU treatment. MALAT1 in human umbilical cord mesenchymal stem cells expedited foot ulcer healing in diabetic rats, particularly in age-associated diabetes, through miR-142 sponge activity. These findings offer insights for novel therapeutic strategies targeting elderly diabetic foot ulcers, emphasizing exogenous stem cell transplantation's potential in effective DFU treatment for the elderly.

Diabetes mellitus is a major cause of blindness and chronic ulcers in the working‐age population worldwide. Wound healing is deeply dependent on neovascularization to restore blood flow. Former research has found that differentially expressed circular RNAs (circRNAs) are associated with hyperglycaemia‐induced endothelial cell damage, and hypoxia‐pretreated adipose‐derived stem cells (ADSCs)‐extracellular vesicle (HEV) transplants have a more therapeutic effect to enhance wound healing in diabetic mice by delivery circRNA. The current investigation employed high‐throughput sequencing to identify circRNAs that are abnormally expressed between EV and HEV. The regulatory mechanism and predicted targets of one differentially expressed circRNA, circ‐IGF1R, were investigated utilizing bioinformatics analyses, luciferase reporter assays, angiogenic differentiation assays, flow cytometric apoptosis analysis and RT‐qPCR. Circ‐IGF1R expression increased in HEV, and downregulation of circ‐IGF1R suppressed and reversed the promotion effect of HEV on angiogenesis in ulcerated tissue. Bioinformatics analyses and luciferase reporter assays confirmed that miR‐503‐5p was the downstream target of circ‐IGF1R, and inhibiting miR‐503‐5p restored the promotion effect of HEV on angiogenesis after circ‐IGF1R silence. The study also found that miR‐503‐5p can interact with 3'‐UTR of both HK2 and VEGFA. Overexpression of HK2 or VEGFA restored the promotion effect of HExo on angiogenesis after circ‐IGF1R silence. Overexpression miR‐503‐5p or silence HK2/VEGFA reversed the protective effect of circ‐IGF1R to MLMECs angiogenic differentiation. Overexpression of circ‐IGF1R increased the protective effect of HEV on the promotion of wound healing in mice with diabetes. Circ‐IGF1R promotes HIF‐1α expression through miR‐503‐5p sponging. Our data demonstrate that circ‐IGF1R overexpression EVs from ADSCs suppress high glucose‐induced endothelial cell damage by regulating miR‐503‐5p/HK2/VEGFA axis.