UCMSCs-derived exosomal circHIPK3 promotes ulcer wound angiogenesis of diabetes mellitus via miR-20b-5p/Nrf2/VEGFA axis

Angio-microRNAs in diabetic foot ulcer-: Mechanistic insights and clinical perspectives

Diabetic foot ulcers, as one of the chronic wounds, are a serious challenge in the global healthcare system which have shown notable growth in recent years. DFU is associated with impairment in various stages of wound healing, including angiogenesis. Aberrant expression of microRNAs (miRNAs) involved in the disruption of the balance between angiogenic and anti-angiogenic factors, plays a crucial role in angiogenesis dysfunction. Alteration in the expression of angiomiRNAs (angiomiRs) have the potential to function as biomarkers in chronic wounds. Additionally, considering the rising importance of therapeutic RNAs, there is potential for utilizing angiomiRs in wound healing to induce angiogenesis. This review aims to explore angiogenesis in chronic wounds and investigate the mechanisms mediated by pro- and anti-angiomiRs in the context of diabetic foot ulcers.

Exosomes and microRNAs: insights into their roles in thermal-induced skin injury, wound healing and scarring

A burn is a type of injury to the skin or other tissues caused by heat, chemicals, electricity, sunlight, or radiation. Burn injuries have been proven to have the potential for long-term detrimental effects on the human body. The conventional therapeutic approaches are not able to effectively and easily heal these burn wounds completely. The main potential drawbacks of these treatments include hypertrophic scarring, contracture, infection, necrosis, allergic reactions, prolonged healing times, and unsatisfactory cosmetic results. The existence of these drawbacks and limitations in current treatment approaches necessitates the need to search for and develop better, more efficient therapies. The regenerative potential of microRNAs (miRNAs) and the exosomal miRNAs derived from various cell types, especially stem cells, offer advantages that outweigh traditional burn wound healing treatment procedures. The use of multiple types of stem cells is gaining interest due to their improved healing efficiency for various applications. Stem cells have several key distinguishing characteristics, including the ability to promote more effective and rapid healing of burn wounds, reduced inflammation levels at the wound site, and less scar tissue formation and fibrosis. In this review, we have discussed the stages of wound healing, the role of exosomes and miRNAs in improving thermal-induced wounds, and the impact of miRNAs in preventing the formation of hypertrophic scars. Research studies, pre-clinical and clinical, on the use of different cell-derived exosomal miRNAs and miRNAs for the treatment of thermal burns have been documented from the year 2000 up to the current time. Studies show that the use of different cell-derived exosomal miRNAs and miRNAs can improve the healing of burn wounds. The migration of exosomal miRNAs to the site of a wound leads to inhibition of apoptosis, induction of autophagy, re-epithelialization, granulation, regeneration of skin appendages, and angiogenesis. In conclusion, this study underscores the importance of integrating miRNA and exosome research into treatment strategies for burn injuries, paving the way for novel therapeutic approaches that could significantly improve patient outcomes and recovery times.

Exosomes from mesenchymal stem cells: Potential applications in wound healing

Wound healing is a continuous and complex process regulated by multiple factors, which has become an intractable clinical burden. Mesenchymal stem cell-derived exosomes (MSC-exos) possess low immunogenicity, easy preservation, and potent bioactivity, which is a mirror to their parental cells MSC-exos are important tools for regulating the biological behaviors of wound healing-associated cells, including fibroblasts, keratinocytes, immune cells, and endothelial cells. MSC-exos accelerate the wound healing process at cellular and animal levels by modulating inflammatory responses, promoting collagen deposition and vascularization. MSC-exos accelerate wound healing at the cellular and animal levels by modulating inflammatory responses and promoting collagen deposition and vascularization. This review summarizes the roles and mechanisms of MSC-exos originating from various sources in promoting the healing efficacy of general wounds, diabetic wounds, burn wounds, and healing-related scars. It also discusses the limitations and perspectives of MSC-exos in wound healing, in terms of exosome acquisition, mechanistic complexity, and exosome potentiation modalities. A deeper understanding of the properties and functions of MSC-exos is beneficial to advance the therapeutic approaches for achieving optimal wound healing.

Advancements in diabetic foot ulcer research: Focus on mesenchymal stem cells and their exosomes

Diabetes represents a widely acknowledged global public health concern. Diabetic foot ulcer (DFU) stands as one of the most severe complications of diabetes, its occurrence imposing a substantial economic burden on patients, profoundly impacting their quality of life. Despite the deepening comprehension regarding the pathophysiology and cellular as well as molecular responses of DFU, the current therapeutic arsenal falls short of efficacy, failing to offer a comprehensive remedy for deep-seated chronic wounds and microvascular occlusions. Conventional treatments merely afford symptomatic alleviation or retard the disease's advancement, devoid of the capacity to effectuate further restitution of compromised vasculature and nerves. An escalating body of research underscores the prominence of mesenchymal stem cells (MSCs) owing to their paracrine attributes and anti-inflammatory prowess, rendering them a focal point in the realm of chronic wound healing. Presently, MSCs have been validated as a highly promising cellular therapeutic approach for DFU, capable of effectuating cellular repair, epithelialization, granulation tissue formation, and neovascularization by means of targeted differentiation, angiogenesis promotion, immunomodulation, and paracrine activities, thereby fostering wound healing. The secretome of MSCs comprises cytokines, growth factors, chemokines, alongside exosomes harboring mRNA, proteins, and microRNAs, possessing immunomodulatory and regenerative properties. The present study provides a systematic exposition on the etiology of DFU and elucidates the intricate molecular mechanisms and diverse functionalities of MSCs in the context of DFU treatment, thereby furnishing pioneering perspectives aimed at harnessing the therapeutic potential of MSCs for DFU management and advancing wound healing processes.

Role of microRNAs in diabetic foot ulcers: Mechanisms and possible interventions

Diabetic foot ulcer (DFU) is a common and serious complication among diabetic patients, and its incidence and difficulty in treatment have placed large burdens on patient health and quality of life. Diabetic foot tissue typically exhibits chronic wounds, ulcers, or necrosis that are difficult to heal, are prone to infection, and, in severe cases, may even lead to amputation. Recent studies have shown that microRNAs (miRNAs) play key roles in the development and healing of DFUs. miRNAs are a class of short noncoding RNA molecules that regulate gene expression to affect cellular functions and physiological processes. miRNAs may be involved in the development of DFUs by regulating cell growth, proliferation, differentiation and apoptosis. miRNAs can also participate in the healing and recovery of DFUs by regulating key steps, such as inflammation, angiogenesis, cell migration and proliferation, tissue repair and matrix remodeling. Therefore, altering the pathological processes of diabetic foot by modulating the expression of miRNAs could improve the recovery and treatment outcomes of patients. This review provides new insights and perspectives for the treatment of DFUs by summarizing the roles of miRNAs in the development and healing of DFUs and the mechanisms.

Natural products modulate phthalate-associated miRNAs and targets

Phthalates are widespread and commonly used plasticizers that lead to adverse health effects. Several natural products provide a protective effect against phthalates. Moreover, microRNAs (miRNAs) are regulated by natural products and phthalates. Therefore, miRNAs' impacts and potential targets may underlie the mechanism of phthalates. However, the relationship between phthalate-modulated miRNAs and phthalate protectors derived from natural products is poorly understood and requires further supporting information. In this paper, we review the adverse effects and potential targets of phthalates on reproductive systems as well as cancer and non-cancer responses. Information on natural products that attenuate the adverse effects of phthalates is retrieved through a search of Google Scholar and the miRDB database. Moreover, information on miRNAs that are upregulated or downregulated in response to phthalates is collected, along with their potential targets. The interplay between phthalate-modulated miRNAs and natural products is established. Overall, this review proposes a straightforward pathway showing how phthalates modulate different miRNAs and targets and cause adverse effects, which are partly attenuated by several natural products, thereby providing a direction for investigating the natural product-miRNA-target axis against phthalate-induced effects.

USP7-stabilised HIPK2 promotes high glucose-induced endothelial cell dysfunctions to accelerate diabetic foot ulcers

Background: This study aimed to explore the molecular mechanism of homeodomain-interacting protein kinase 2 (HIPK2) in diabetic foot ulcers (DFU).

Methods: High glucose (HG)-induced human umbilical vein endothelial cells (HUVECs) were used to construct DFU cell models. Cell functions were determined using CCK8 assay, EdU assay, flow cytometry, transwell assay, wound healing assay and tube formation assay. Quantitative real-time PCR and western blot were applied to measure the gene expression.

Results: HG treatment suppressed HUVECs proliferation, invasion, migration, and angiogenesis, while enhanced apoptosis. HIPK2 was overexpressed in DFU patients, and its knockdown alleviated HG-induced HUVECs dysfunctions. USP7 stabilised HIPK2 protein by reducing its ubiquitination. USP7 overexpression promoted HG-induced HUVECs dysfunctions, and HIPK2 upregulation also reversed the regulation of USP7 knockdown on HG-induced HUVECs dysfunctions. USP7/HIPK2 axis inhibited the activity of PI3K/AKT pathway.

Conclusion: Our study revealed that USP7-stabilised HIPK2 contributed to HG-induced HUVECs dysfunctions, thus accelerating DFU process.

Bioengineered mesenchymal stem cell-derived exosomes: emerging strategies for diabetic wound healing

Diabetic wounds are among the most common complications of diabetes mellitus and their healing process can be delayed due to persistent inflammatory reactions, bacterial infections, damaged vascularization and impaired cell proliferation, which casts a blight on patients'health and quality of life. Therefore, new strategies to accelerate diabetic wound healing are being positively explored. Exosomes derived from mesenchymal stem cells (MSC-Exos) can inherit the therapeutic and reparative abilities of stem cells and play a crucial role in diabetic wound healing. However, poor targeting, low concentrations of therapeutic molecules, easy removal from wounds and limited yield of MSC-Exos are challenging for clinical applications. Bioengineering techniques have recently gained attention for their ability to enhance the efficacy and yield of MSC-Exos. In this review, we summarise the role of MSC-Exos in diabetic wound healing and focus on three bioengineering strategies, namely, parental MSC-Exos engineering, direct MSC-Exos engineering and MSC-Exos combined with biomaterials. Furthermore, the application of bioengineered MSC-Exos in diabetic wound healing is reviewed. Finally, we discuss the future prospects of bioengineered MSC-Exos, providing new insights into the exploration of therapeutic strategies.

Exosomes: compositions, biogenesis, and mechanisms in diabetic wound healing

Diabetic wounds are characterized by incomplete healing and delayed healing, resulting in a considerable global health care burden. Exosomes are lipid bilayer structures secreted by nearly all cells and express characteristic conserved proteins and parent cell-associated proteins. Exosomes harbor a diverse range of biologically active macromolecules and small molecules that can act as messengers between different cells, triggering functional changes in recipient cells and thus endowing the ability to cure various diseases, including diabetic wounds. Exosomes accelerate diabetic wound healing by regulating cellular function, inhibiting oxidative stress damage, suppressing the inflammatory response, promoting vascular regeneration, accelerating epithelial regeneration, facilitating collagen remodeling, and reducing scarring. Exosomes from different tissues or cells potentially possess functions of varying levels and can promote wound healing. For example, mesenchymal stem cell-derived exosomes (MSC-exos) have favorable potential in the field of healing due to their superior stability, permeability, biocompatibility, and immunomodulatory properties. Exosomes, which are derived from skin cellular components, can modulate inflammation and promote the regeneration of key skin cells, which in turn promotes skin healing. Therefore, this review mainly emphasizes the roles and mechanisms of exosomes from different sources, represented by MSCs and skin sources, in improving diabetic wound healing. A deeper understanding of therapeutic exosomes will yield promising candidates and perspectives for diabetic wound healing management.

Theaflavin-3,3'-Digallate Protects Liver and Kidney Functions in Diabetic Rats by Up-Regulating Circ-ITCH and Nrf2 Signaling Pathway

Theaflavin-3,3'-digallate (TFDG) in black tea has a strong antioxidant capacity. However, its effect on diabetic liver and kidney injury and the underlying mechanisms remain unclear. In the present study, our findings indicated that TFDG administration effectively lowers the fasting blood glucose and serum lipid concentrations and enhances the functionality and cellular architecture of the liver and kidney in rats with diabetes. The data also showed that TFDG mitigates oxidative harm in the liver and kidney of rats afflicted with diabetes. Additionally, metformin combined with TFDG was significantly more effective in reducing blood glucose and oxidative stress. Further studies suggested that TFDG upregulates the Nrf2 signal pathway and circ-ITCH (hsa_circ_0001141) expression. Silencing of circ-ITCH by transfection of the interfering plasmid apparently reduces the effects of TFDG on the Nrf2 signal pathway and oxidative stress in high-glucose-treated hepatic and renal cells. In conclusion, the present study highlights the great potential of TFDG in ameliorating diabetic liver and kidney injury by up-regulating circ-ITCH to promote the Nrf2 signal pathway and provides a potential option for the prevention and treatment of diabetic complications.

Upregulation of circ-IGF1R increased therapeutic effect of hypoxia-pretreated ADSC-derived extracellular vesicle by regulating miR-503-5p/HK2/VEGFA axis

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.

Preclinical and Clinical Studies on the Use of Extracellular Vesicles Derived from Mesenchymal Stem Cells in the Treatment of Chronic Wounds

To date, the widespread implementation of therapeutic strategies for the treatment of chronic wounds, including debridement, infection control, and the use of grafts and various dressings, has been time-consuming and accompanied by many challenges, with definite success not yet achieved. Extensive studies on mesenchymal stem cells (MSCs) have led to suggestions for their use in treating various diseases. Given the existing barriers to utilizing such cells and numerous pieces of evidence indicating the crucial role of the paracrine signaling system in treatments involving MSCs, extracellular vesicles (EVs) derived from these cells have garnered significant attention in treating chronic wounds in recent years. This review begins with a general overview of current methods for chronic wound treatment, followed by an exploration of EV structure, biogenesis, extraction methods, and characterization. Subsequently, utilizing databases such as Google Scholar, PubMed, and ScienceDirect, we have explored the latest findings regarding the role of EVs in the healing of chronic wounds, particularly diabetic and burn wounds. In this context, the role and mode of action of these nanoparticles in healing chronic wounds through mechanisms such as oxygen level elevation, oxidative stress damage reduction, angiogenesis promotion, macrophage polarization assistance, etc., as well as the use of EVs as carriers for engineered nucleic acids, have been investigated. The upcoming challenges in translating EV-based treatments for healing chronic wounds, along with possible approaches to address these challenges, are discussed. Additionally, clinical trial studies in this field are also covered.

Construction of lncRNA- and circRNA-associated ceRNA networks in the prostatic urethra of rats after simulating transurethral laser prostatectomy (TULP)

Non-coding RNA appears to be involved in wound repair. Competing endogenous RNA (ceRNA) appears to be an important post-transcriptional mechanism, it means that long noncoding RNA (lncRNA) or circular RNA (circRNA) acts as a microRNA (miRNA) sponge to further regulate mRNA. However, ceRNA network related to wound repair after prostatectomy has yet been constructed. TULP is the main surgical method of prostatectomy, but there have been no reports of TULP rat models in the past. We simulated TULP on rats, and observed the whole process of wound injury and repair after operation through pathological examination of wound tissue. Next, we discovered 732 differentially expressed lncRNAs (DElncRNAs), 47 differentially expressed circRNAs (DEcircRNAs), 17 differentially expressed miRNAs (DEmiRNAs), and 1892 differentially expressed mRNAs (DEmRNAs) related to wound repair after TULP through full transcriptome microarray and bioinformatics methods, and confirmed the reliability of transcriptome data by quantitative Reverse Transcription PCR (qRT-PCR), and immunohistochemistry. Then, we constructed the lncRNA- and circRNA-associated ceRNA regulatory networks related to wound repair after TULP in rats. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that molecules in these networks were mainly involved in inflammatory infiltration, cell differentiation, and intercellular interactions and involved signal pathways such as the PI3K-Akt signaling pathway. Thus, this study successfully established the TULP model in rats, revealed potentially important biomarkers and ceRNA networks after prostatectomy in rats, and provided theoretical support for the repair of post-prostatectomy wound.

The role of exosome derived miRNAs in inter-cell crosstalk among insulin-related organs in type 2 diabetes mellitus

Exosomes are small extracellular vesicles secreted by almost all cell types, and carry diverse cargo including RNA, and other substances. Recent studies have focused exosomal microRNAs (miRNAs) on various human diseases, including type 2 diabetes mellitus (T2DM) and metabolic syndrome (METS) which accompany the occurrence of insulin resistance. The regulation of insulin signaling has connected with some miRNA expression which play a significant regulatory character in insulin targeted cells or organs, such as fat, muscle, and liver. The miRNAs carried by exosomes, through the circulation in the body fluids, mediate all kinds of physiological and pathological process involved in the human body. Studies have found that exosome derived miRNAs are abnormally expressed and cross-talked with insulin targeted cells or organs to affect insulin pathways. Further investigations of the mechanisms of exosomal miRNAs in T2DM will be valuable for the diagnostic biomarkers and therapeutic targets of T2DM. This review will summarize the molecular mechanism of action of the miRNAs carried by exosomes which are secreted from insulin signaling related cells, and elucidate the pathogenesis of insulin resistance to provide a new strategy for the potential diagnostic biomarkers and therapeutic targets for the type 2 diabetes.

Exosomes derived from mesenchymal stem cells in diabetes and diabetic complications

Diabetes, a group of metabolic disorders, constitutes an important global health problem. Diabetes and its complications place a heavy financial strain on both patients and the global healthcare establishment. The lack of effective treatments contributes to this pessimistic situation and negative outlook. Exosomes released from mesenchymal stromal cells (MSCs) have emerged as the most likely new breakthrough and advancement in treating of diabetes and diabetes-associated complication due to its capacity of intercellular communication, modulating the local microenvironment, and regulating cellular processes. In the present review, we briefly outlined the properties of MSCs-derived exosomes, provided a thorough summary of their biological functions and potential uses in diabetes and its related complications.

Umbilical cord-derived mesenchymal stem cell secretome promotes skin regeneration and rejuvenation: From mechanism to therapeutics

How to effectively repair cutaneous wounds and promote skin rejuvenation has always been a challenging issue for clinical medicine and medical aesthetics. Current conventional medicines exhibit several drawbacks, including limited therapeutic effects, prolonged treatment periods, and high costs. As a novel cell-free therapy, the umbilical cord-derived mesenchymal stem cell (UCMSC) secretome may offer a promising approach for skin regeneration and rejuvenation. The UCMSC secretome is a collection of all proteins secreted by mesenchymal stem cells, including conditioned media, exosomes, and other substances. The UCMSC secretome has numerous abilities to accelerate acute wound healing, including high fibroblast and keratinocyte proliferative activity, pro-angiogenesis, anti-inflammation, anti-fibrosis, and anti-oxidative stress. Its impact on the four stages of wound healing is manifested by inducing the haemostasis phase, inhibiting the inflammation phase, promoting the proliferation phase, and regulating the remodelling phase. Furthermore, it is highly effective in the treatment of chronic wounds, alopecia, aging, and skin homeostasis disturbance. This review focuses on the clinical therapies and application prospects of the UCMSC secretome, encompassing its source, culture, separation, identification, storage, and pretreatment. Additionally, a discussion on the dosage, administration route, efficacy, and biosafety in the clinical situation is presented. This review aims to provide scientific support for the mechanistic investigation and clinical utilisation of the UCMSC secretome in wound healing and skin rejuvenation.

Nrf2 activation: a key mechanism in stem cell exosomes-mediated therapies

Exosomes are nano-sized membrane extracellular vesicles which can be released from various types of cells. Exosomes originating from inflammatory or injured cells can have detrimental effects on recipient cells, while exosomes derived from stem cells not only facilitate the repair and regeneration of damaged tissues but also inhibit inflammation and provide protective effects against various diseases, suggesting they may serve as an alternative strategy of stem cells transplantation. Exosomes have a fundamental role in communication between cells, through the transfer of proteins, bioactive lipids and nucleic acids (like miRNAs and mRNAs) between cells. This transfer significantly impacts both the physiological and pathological functions of recipient cells. Nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor, is able to mitigate damage caused by oxidative stress and inflammation through various signaling pathways. The positive effects resulting from the activation of the Nrf2 signaling pathway in different disorders have been documented in various types of literature. Studies have confirmed that exosomes derived from stem cells could act as Nrf2 effective agonists. However, limited studies have explored the Nrf2 role in the therapeutic effects of stem cell-derived exosomes. This review provides a comprehensive overview of the existing knowledge concerning the role of Nrf2 signaling pathways in the impact exerted by stem cell exosomes in some common diseases.

Non-coding RNAs in diabetic foot ulcer- a focus on infected wounds

Diabetes mellitus is associated with a wide range of neuropathies, vasculopathies, and immunopathies, resulting in many complications. More than 30% of diabetic patients risk developing diabetic foot ulcers (DFUs). Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), play essential roles in various biological functions in the hyperglycaemic environment that determines the development of DFU. Ulceration results in tissue breakdown and skin barrier scavenging, thereby facilitating bacterial infection and biofilm formation. Many bacteria contribute to diabetic foot infection (DFI), including Staphylococcus aureus (S. aureus) et al. A heterogeneous group of "ncRNAs," termed small RNAs (sRNAs), powerfully regulates biofilm formation and DFI healing. Multidisciplinary foot care interventions have been identified for nonhealing ulcers. With an appreciation of the link between disease processes and ncRNAs, a novel therapeutic model of bioactive materials loaded with ncRNAs has been developed to prevent and manage diabetic foot complications.

HMOX1-overexpressing mesenchymal stem cell-derived exosomes facilitate diabetic wound healing by promoting angiogenesis and fibroblast function

Many scholars have suggested that exosomes (Exos) can carry active molecules to induce angiogenesis and thus accelerate diabetic wound healing. Heme oxygenase-1 (HO-1) encoded by the gene HMOX1 promotes wound healing in DM by enhancing angiogenesis. Nevertheless, whether HMOX1 regulates wound healing in DM through mesenchymal stem cell-derived exosomes (MSC-Exos) remains to be further explored. The primary isolated- and cultured-cells expressed MSC-specific marker proteins, and had low immunogenicity and multi-differentiation potential, which means that MSCs were successfully isolated in this study. Notably, HO-1 protein expression was significantly higher in Exo-HMOX1 than in Exos, indicating that HMOX1 could be delivered to Exos as an MSCs-secreted protein. After verifying the -Exo structure, fibroblasts, keratinocytes, and human umbilical vein endothelial cells (HUVECs) were incubated with Exo-HMOX1 or Exo, and the findings displayed that Exo-HMOX1 introduction promoted the proliferation and migration of fibroblasts, keratinocytes and the angiogenic ability of HUVECs in vitro study. After establishing diabetic wound model mice, PBS, Exo, and Exo-HMOX1 were subcutaneously injected into multiple sites on the 1st, 3rd, 7th, and 14th day, DM injected with Exo-HMOX1 showed faster wound healing, re-epithelialization, collagen deposition, and angiogenesis than those in PBS and Exo groups in vitro study. In summary, Exo-HMOX1 could enhance the activity of fibroblasts, keratinocytes, and HUVEC, and accelerate wound healing by promoting angiogenesis in DM.

IFN-γ enhances the therapeutic efficacy of MSCs-derived exosome via miR-126-3p in diabetic wound healing by targeting SPRED1

BACKGROUND AND AIMS

The traditional treatment of diabetic wounds is unsatisfactory. Exosomes isolated from bone marrow mesenchymal stem cells (BMSCs) promote the healing of diabetic wounds. However, whether the exosomes secreted by interferon (IFN)-γ-pretreated BMSCs have an enhanced therapeutic effect on diabetic wound healing and the relevant mechanisms remain unclear.

METHODS

In this study, we isolated exosomes from the corresponding supernatants of BMSCs with (IExos) or without IFN-γ treatment (NExos). Human umbilical vein endothelial cells (HUVECs) were used to investigate the proliferation, migration, and tube formation under different treatments in vitro. Diabetic mice were induced by intraperitoneal administration of streptozotocin, and a circular full-thickness dermal defect was then made on the back of each mouse, followed by a multisite subcutaneous injection of phosphate buffered saline or exosomes. Hematoxylin-eosin (H&E) staining, Masson's trichrome staining, and histological analysis were performed to assess the speed and quality of wound healing.

RESULTS

NExos treatment accelerated the healing of diabetic wounds by promoting angiogenesis in vivo and in vitro, and IExos exhibited superior therapeutic efficiency. MicroRNA (miR)-126-3p was significantly increased in IExos, and exosomal miR-126-3p promoted angiogenesis and diabetic wound healing via its transfer to HUVECs. miR-126-3p regulates SPRED1 by directly targeting the 3'-UTR. Mechanistically, IFN-γ-pretreated BMSCs secreted miR-126-3p-enriched exosomes, which enhanced the function of HUVECs and promoted angiogenesis via the SPRED1/Ras/Erk pathway.

CONCLUSION

Exosomal miR-126-3p secreted from IFN-γ-pretreated BMSCs exhibited higher therapeutic efficacy than NExos in diabetic wound healing by promoting angiogenesis via the SPRED1/Ras/Erk axis.

Targeting Signalling Pathways in Chronic Wound Healing

Chronic wounds fail to achieve complete closure and are an economic burden to healthcare systems due to the limited treatment options and constant medical attention. Chronic wounds are characterised by dysregulated signalling pathways. Research has focused on naturally derived compounds, stem-cell-based therapy, small molecule drugs, oligonucleotide delivery nanoparticles, exosomes and peptide-based platforms. The phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT), Wingless-related integration (Wnt)/β-catenin, transforming growth factor-β (TGF-β), nuclear factor erythroid 2-related factor 2 (Nrf2), Notch and hypoxia-inducible factor 1 (HIF-1) signalling pathways have critical roles in wound healing by modulating the inflammatory, proliferative and remodelling phases. Moreover, several regulators of the signalling pathways were demonstrated to be potential treatment targets. In this review, the current research on targeting signalling pathways under chronic wound conditions will be discussed together with implications for future studies.

Exosomal circHIPK3 derived from umbilical cord-derived mesenchymal stem cells enhances skin fibroblast autophagy by blocking miR-20b-5p/ULK1/Atg13 axis

BACKGROUND

Umbilical cord-derived mesenchymal stem cells (UCMSCs) could alleviate diabetes-induced injury. Hence, this investigation aimed to explore the role and mechanism of UCMSCs-derived exosomal circHIPK3 (exo-circHIPK3) in diabetes mellitus (DM).

METHODS

HFF-1 cells were cultured in high glucose (HG) medium or normal medium, and treated with UCMSCs-derived exo-circHIPK3 or miR-20b-5p mimics or Unc-51-like autophagy activating kinase 1 (ULK1) overexpression vector. The surface markers of UCMSCs were analyzed using a flow cytometer. The differentiation potential of UCMSCs was evaluated using oil red O staining, alizarin red staining and alkaline phosphatase (ALP) staining. Cell proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The miRNA expressions were analyzed by reverse transcription-quantitative polymerase chain reaction (qRT-PCR). Protein levels were quantified by western blot. An immunofluorescence staining was used for observing LC3 expression. The interaction between miR-20b-5p and circHIPK3, and between miR-20b-5b and ULK1 were identified by a RNA immunoprecipitation (RIP) assay and a luciferase reporter assay.

RESULTS

Up-regulation of circHIPK3 was found in UCMSCs-derived exosomes. Exo-circHIPK3 decreased the miR-20b-5p level while increasing the contents of ULK1 and autophagy-related gene 13 (Atg13) in HG-induced fibroblasts. In addition, exo-circHIPK3 activated HG-induced fibroblast autophagy and proliferation. Overexpressed miR-20b-5p promoted fibroblast injury by inhibiting cell autophagy via the ULK1/Atg13 axis in HG conditions of high glucose. Moreover, exo-circHIPK3 enhanced autophagy and cell viability in HG-induced fibroblasts through the miR-20b-5p/ULK1/Atg13 axis.

CONCLUSION

UCMSCs-derived exosomal circHIPK3 promoted cell autophagy and proliferation and accelerated the fibroblast injury repair by the miR-20b-5p/ULK1/Atg13 axis.

The role of programmed cell death in diabetic foot ulcers

Diabetic foot ulcer, is a chronic complication afflicting individuals with diabetes, continue to increase worldwide, immensely burdening society. Programmed cell death, which includes apoptosis, autophagy, ferroptosis, necroptosis and pyroptosis, has been increasingly implicated in the pathogenesis of diabetic foot ulcer. This review is based on an exhaustive examination of the literature on 'programmed cell death' and 'diabetic foot ulcers' via PubMed. The findings revealed that natural bioactive compounds, noncoding RNAs and certain proteins play crucial roles in the healing of diabetic foot ulcers through various forms of programmed cell death, including apoptosis, autophagy, ferroptosis and pyroptosis.

Circ_072697 knockdown promotes advanced glycation end products-induced cell proliferation and migration in HaCaT cells via miR-3150a-3p/KDM2A axis

OBJECTIVE

Diabetes foot ulcer (DFU) is a serious complication of diabetes, which can lead to significant mortality and amputation rate. Our previous study found circ_072697 was highly expressed in DFU tissues, but the regulatory mechanism of circ_072697 in DFU remains unclear.

METHODS

The relative expressions of circ_072697, miR-3150a-3p, and KDM2A in DFU patients or advanced glycation end products (AGEs)-treated HaCaT cells (used as DFU cell model) were determined by using qRT-PCR. Cell proliferation and migration abilities were determined by using CCK-8 and Transwell assays. The interaction between miR-3150a-3p with circ_072697 or KDM2A were verified by RNA immunoprecipitation (RIP) and dual-luciferase reporter assays. Furthermore, the protein expression of genes involved in MAPK signaling pathway was detected by western blot.

RESULTS

The expression of circ_072697 was significantly upregulated in DFU tissues, while the expression of miR-3150a-3p was downregulated. Circ_072697 knockdown promoted the proliferation and migration of AGEs-treated HaCaT cells. miR-3150a-3p was confirmed as a target of circ_072697 and its inhibitor reversed the promotion effects of circ_072697 knockdown on biological behavior of cells. In addition, KDM2A was considered as a target of miR-3150a-3p and it was highly expressed in DFU samples. Importantly, circ_072697 could regulate KDM2A expression through sponging miR-3150a-3p, and this axis had effect on the MAPK signaling pathway.

CONCLUSIONS

Overall, circ_072697 regulated the biological behaviors of keratinocytes in DFU via miR-3150a-3p/KDM2A axis and MAPK signaling pathway, revealing a new insight into the pathogenesis and potential therapeutic targets of DFU.

Effects of microRNAs on angiogenesis in diabetic wounds

Diabetes mellitus is a morbid condition affecting a growing number of the world population, and approximately one third of diabetic patients are afflicted with diabetic foot ulcers (DFU), which are chronic non-healing wounds that frequently progress to require amputation. The treatments currently used for DFU focus on reducing pressure on the wound, staving off infection, and maintaining a moist environment, but the impaired wound healing that occurs in diabetes is a constant obstacle that must be faced. Aberrant angiogenesis is a major contributor to poor wound healing in diabetes and surgical intervention is often necessary to establish peripheral blood flow necessary for healing wounds. Over recent years, microRNAs (miRNAs) have been implicated in the dysregulation of angiogenesis in multiple pathologies including diabetes. This review explores the pathways of angiogenesis that become dysregulated in diabetes, focusing on miRNAs that have been identified and the mechanisms by which they affect angiogenesis.

Non-coding RNAs: Role in diabetic foot and wound healing

Diabetic foot ulcer (DFU) and poor wound healing are chronic complications in patients with diabetes. The increasing incidence of DFU has resulted in huge pressure worldwide. Diagnosing and treating this condition are therefore of great importance to control morbidity and improve prognosis. Finding new markers with potential diagnostic and therapeutic utility in DFU has gathered increasing interest. Wound healing is a process divided into three stages: Inflammation, proliferation, and regeneration. Non-coding RNAs (ncRNAs), which are small protected molecules transcribed from the genome without protein translation function, have emerged as important regulators of diabetes complications. The deregulation of ncRNAs may be linked to accelerated DFU development and delayed wound healing. Moreover, ncRNAs can be used for therapeutic purposes in diabetic wound healing. Herein, we summarize the role of microRNAs, long ncRNAs, and circular RNAs in diverse stages of DFU wound healing and their potential use as novel therapeutic targets.