Augmentation of hypoxia-inducible factor-1-alpha in reinfused blood cells enhances diabetic ischemic wound closure in mice

Healing the diabetic wound: Unlocking the secrets of genes and pathways

Diabetic wounds (DWs) are open sores that can occur anywhere on a diabetic patient's body. They are often complicated by infections, hypoxia, oxidative stress, hyperglycemia, and reduced growth factors and nucleic acids. The healing process involves four phases: homeostasis, inflammation, proliferation, and remodeling, regulated by various cellular and molecular events. Numerous genes and signaling pathways such as VEGF, TGF-β, NF-κB, PPAR-γ, MMPs, IGF, FGF, PDGF, EGF, NOX, TLR, JAK-STAT, PI3K-Akt, MAPK, ERK, JNK, p38, Wnt/β-catenin, Hedgehog, Notch, Hippo, FAK, Integrin, and Src pathways are involved in these events. These pathways and genes are often dysregulated in DWs leading to impaired healing. The present review sheds light on the pathogenesis, healing process, signaling pathways, and genes involved in DW. Further, various therapeutic strategies that target these pathways and genes via nanotechnology are also discussed. Additionally, clinical trials on DW related to gene therapy are also covered in the present review.

Polyvinylpyrrolidone/chitosan-loaded dihydromyricetin-based nanofiber membrane promotes diabetic wound healing by anti-inflammatory and regulating autophagy-associated protein expression

The healing of wounds in diabetics is commonly delayed by recurring infections and persistent inflammation at the wound site. For this reason, we conducted a study using the electrospinning technique to create nanofiber membranes consisting of polyvinylpyrrolidone/chitosan (PVP/CS) and incorporated dihydromyricetin (DHM) into them. Infrared Fourier transform spectroscopy and scanning electron microscopy were used to analyze the nanofiber membrane. Experimental results in vitro have shown that PVP/CS/DHM has exceptional properties such as hydrophilicity, porosity, water vapor transport rate, antioxidant capacity, and antibacterial activity. Moreover, our study has demonstrated that the application of PVP/CS/DHM can significantly improve wound healing in diabetic mice. After an 18-day treatment period, a remarkable wound closure rate of 88.63 ± 1.37 % was achieved. The in vivo experiments revealed that PVP/CS/DHM can promote diabetic wound healing by suppressing the activation of TLR4/MyD88/NF-κB signaling pathway and enhancing autophagy-related protein as well as CD31 and HIF-1α expression in skin tissues. This study showed that PVP/CS/DHM is a promising wound dressing.

Dapagliflozin-Loaded Exosome Mimetics Facilitate Diabetic Wound Healing by HIF-1α-Mediated Enhancement of Angiogenesis

Angiogenesis plays a critical role in diabetic wound healing. However, no effective strategies have been developed to target endothelial cells (ECs) to facilitate diabetic wound healing. Dapagliflozin (DA) as a sodium-glucose linked transporter 2 (SGLT2) inhibitor, may promote neovascularization in diabetic mice via HIF-1α-mediated enhancement of angiogenesis. Here, the bioinspired nanovesicles (NVs) prepared from induced pluripotent stem cells-derived ECs through an extrusion approach are reported, which can function as exosome mimetics to achieve targeted deliver of DA. Abundant membrane C-X-C motif chemokine receptor 4 conferred the EC-targeting ability of these NVs and the endothelial homology facilitated the accumulation in ECs. Furthermore, these DA-loaded induced pluripotent stem cells (iPSC)-EC NVs can facilitate angiogenesis and diabetic wound healing by HIF-1α/VEGFA pathway. Taken together, this study indicated that targeting ECs and regulating angiogenesis may be a promising strategy for the treatment of diabetic wound healing.

Multifunction gelatin/chitosan composite microspheres with ROS-scavenging and antibacterial activities for improving the microenvironment of chronic wounds

Multifunction gelatin/chitosan composite microspheres with ROS-scavenging and antibacterial activities for chronic wound healing.

HIF1α 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)1α plays important roles in wound healing, and in this study, we investigated the effects of HIF1α 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 HIF1α-overexpressing ADSCs were induced by transduction. The mRNA and protein levels of angiogenic growth factors in control and HIF1α-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 HIF1α 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, HIF1α 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. HIF1α 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, HIF1α overexpression in ADSCs prior to transplantation significantly enhanced angiogenic growth factor expression, promoting wound closure in diabetic mice.

Conclusions

HIF1α 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.

Autologous blood transfusion stimulates wound healing in diabetic mice through activation of the HIF-1α pathway by improving the blood preservation solution

Transfusion of autologous blood is a timesaving, convenient, safe, and effective therapy from a clinical perspective, and often employed for the treatment of diabetic patients. Stabilization of HIF-1α has been widely reported to be a critical factor in the improvement of wound healing in diabetes. Therefore, our study reveals the roles of improved autologous blood in wound healing in diabetes, through autologous blood transfusion in a mouse model. Initially, BALB/c mice were subjected to streptozotocin for diabetic mouse model establishment. Diabetic mice were transfused with improved or standard autologous blood in perfusion culture system. Roles of improved autologous blood in mediating HIF-1α pathway were determined by measuring expression of VEGF, EGF, HIF-1α, and HSP-90. In order to assess the detailed regulatory mechanism of improved autologous blood in perspective of wound healing, cell proliferation, migration and cell cycle, fibroblasts isolated from diabetic mice were transfected with HIF-1α siRNA. Mice transfused with improved autologous blood exhibited increased levels of CD31 and α-SMA in skin tissues, and reduced TNF-α, IL-1β, and IL-6 levels, indicating that improved autologous blood promoted wound healing ability and reduced the release of inflammatory factors. Diabetic mice transfused with improved autologous blood presented activated HIF-1α pathway. The survival rate, proliferation, and migration of fibroblasts were elevated via activation of the HIF-1α pathway. Taken together, improved blood preservation solution could enhance the oxygen carrying capacity of red blood cells and wound healing in mice with diabetes, which is achieved through regulation of HIF-1α pathway.