Exosomes from circ-Astn1-modified adipose-derived mesenchymal stem cells enhance wound healing through miR-138-5p/SIRT1/FOXO1 axis regulation

Inhibition of miRNA-365-2-5p Targeting SIRT1 Regulates Functions of Keratinocytes to Enhance Wound Healing

The development of drugs to accelerate wound healing is an important area of clinical research. Recent advancements have highlighted the prospects of microRNAs as therapeutic targets for various disorders, although their involvement in mice wound healing remains unclear. Peptides have been proved to be unique and irreplaceable molecules in the elucidation of competing endogenous RNAs mechanisms (ceRNA) involved with skin wound healing. In the present work, CyRL-QN15, a peptide characterized by its minimal length and maximal wound healing efficacy, was applied as a probe to explore the ceRNA mechanism in regard to accelerated wound healing. Results showed that the use of CyRL-QN15 significantly reduced the expression of miRNA-365-2-5p at the wound in mice. In mouse keratinocytes, miRNA-365-2-5p inhibition increased SIRT1 and FOXO1 protein expression and decreased STAT2 protein expression, promoting cell proliferation, migration, and reducing inflammatory factors. Similarly, inhibiting miRNA-365-2-5p at mouse wounds promoted Full-thickness injured skin wounds healing, increased SIRT1 and FOXO1 protein expression, decreased STAT2 protein expression, and reduced inflammatory factors. Overall, these findings demonstrate that miRNA-365-2-5p serves a crucial function in the biological processes underlying cutaneous wound healing in mice, offering a novel target for future therapeutic interventions in wound healing.

Non-coding RNAs in adipose-derived stem cell exosomes: Mechanisms, therapeutic potential, and challenges in wound healing

The treatment of complex wounds presents a significant clinical challenge due to the limited availability of standardized therapeutic options. Adipose-derived stem cell exosomes (ADSC-Exos) are promising for their capabilities to enhance angiogenesis, mitigate oxidative stress, modulate inflammatory pathways, support skin cell regeneration, and promote epithelialization. These exosomes deliver non-coding RNAs, including microRNAs, long non-coding RNAs, and circular RNAs, which facilitate collagen remodeling, reduce scar formation, and expedite wound healing. This study reviews the mechanisms, therapeutic roles, and challenges of non-coding RNA-loaded ADSC-Exos in wound healing and identifies critical directions for future research. It aims to provide insights for researchers into the potential mechanisms and clinical applications of ADSC-Exos non-coding RNAs in wound healing.

Administration of hypoxic pretreated adipose-derived mesenchymal stem cell exosomes promotes spinal cord repair after injury via delivery of circ-Astn1 and activation of autophagy

BACKGROUND

The aim of this study was to investigate the role and mechanism of exosomes isolated from adipose-derived mesenchymal stem cells (ADSCs) on spinal cord repair.

METHODS

High-throughput sequencing was used to investigate abnormal expression of circular RNA (circRNA) in ADSC exosomes pretreated under hypoxic conditions (HExos) and ADSCs exosomes under normal conditions (Exos). The abnormal expression of mRNA in spinal cord tissues was also analyzed using high-throughput sequencing. Bioinformatics and luciferase reporter analyses were used to clarify the relationship among circRNA, micro RNA (miRNA), and mRNA. BV2 cells were used to analyze apoptosis levels and inflammatory cytokine expression under oxygen-glucose deprivation (OGD) conditions by using immunofluorescence and enzyme-linked immunosorbent assay (ELISAs). An SCI mouse model was also constructed and the therapeutic effect of Exos was detected using immunohistochemistry and immunofluorescence.

RESULTS

High-throughput sequencing results showed that circ-Astn1 played a role in HExo-mediated spinal cord repair after SCI. Downregulation of circ-Astn1 decreased the therapeutic effect of HExos. We also found that Atg7 played a role in HExo-mediated spinal cord repair after SCI. Luciferase reporter analysis confirmed that both miR-138-5p and Atg7 were downstream targets of circ-Astn1. Downregulation of Atg7 or overexpression of miR-138-5p reversed the protective effect of circ-Astn1 on BV2 cells after exposure to OGD conditions. In contrast, upregulation of circ-Astn1 increased the therapeutic effects of Exo-mediated spinal cord repair after SCI via autophagy activation.

CONCLUSIONS

Taken together, the results indicate that ADSC-Exos containing circ-Astn1 promoted spinal cord repair after SCI by targeting the miR-138-5p/Atg7 pathway, which mediated autophagy.

CircAars-Engineered ADSCs Facilitate Maxillofacial Bone Defects Repair Via Synergistic Capability of Osteogenic Differentiation, Macrophage Polarization and Angiogenesis

Adipose-derived stem cells (ADSCs) hold significant promise in bone tissue engineering due to their self-renewal capacity and easy accessibility. However, their limited osteogenic potential remains a critical challenge for clinical application in bone repair. Emerging evidence suggests that circular RNAs (circRNAs) play a key role in regulating stem cell fate and osteogenesis. Despite this, the specific mechanisms by which circRNAs influence ADSCs in the context of bone tissue engineering are largely unexplored. This study introduces a novel strategy utilizing circAars, a specific circRNA, to modify ADSCs, which are then incorporated into gelatin methacryloyl (GelMA) hydrogels for the repair of critical-sized maxillofacial bone defects. The findings reveal that circAars predominantly localizes in the cytoplasm of ADSCs, where it acts as a competitive sponge for miR-128-3p, enhancing the osteogenic differentiation and migration capabilities of ADSCs. Furthermore, circAars-engineered ADSCs facilitate macrophage polarization from the M1 to M2 phenotype and enhance endothelial cell (EC) angiogenic potential through a paracrine mechanism. Additionally, GelMA scaffolds loaded with circAars-engineered ADSCs accelerate the repair of critical-sized maxillofacial bone defects by synergistically promoting osteogenesis, macrophage M2 polarization, and angiogenesis. This approach offers a promising therapeutic strategy for the treatment of critical-sized maxillofacial defects.

Mesenchymal stem cells-derived small extracellular vesicles and apoptotic extracellular vesicles for wound healing and skin regeneration: a systematic review and meta-analysis of preclinical studies

BACKGROUND

Studies examining the therapeutic potential of Mesenchymal stem cells-derived extracellular vesicles (MSC-EVs) in wound healing and skin regeneration have progressed rapidly. Prior to considering clinical translation, a systematic and comprehensive understanding of these experimental details and the overall impact of MSC-EVs on skin regeneration is necessary.

METHODS

83 studies were identified in Web of Science, Embase, and PubMed that satisfied a set of prespecified inclusion criteria. A random effects meta-analysis was conducted for wound closure rate, scar width, blood vessel density and collagen deposition.

CONCLUSIONS

Our findings demonstrate clear potential of MSC-EVs to be developed as therapy for wound healing and skin regeneration both in diabetic and non-diabetic animal models. Moreover, subgroup analyses demonstrated that apoptotic small extracellular vesicles (ApoSEVs) showed better efficacy than apoptotic bodies (ApoBDs) and small extracellular vesicles (sEVs) in wound closure outcome and collagen deposition, while sEVs displayed better than ApoEVs in revascularization. Among frequently used routes of administration, subcutaneous injection displayed a greater improvement to wound closure, collagen deposition and revascularization as compared to dressing/covering. Among easier-access source of MSCs, ADSCs demonstrated the best effect in wound closure rate and collagen deposition, as compared, BMMSCs displayed better in revascularization. Additionally, high heterogeneity observed in collection conditions, separation methods, storage methods, modifications, treatment dose, administration route, and frequency of MSC-EVs underscores the urgent need for standardization in these areas, prior to clinical translation.

PROTOCOL REGISTRATION

PROSPERO CRD42024499172.

miR-138-5p inhibits healing of femoral fracture osteogenesis in rats by modulating osteoblast differentiation via SIRT1/FOXO1 axis

BACKGROUND

MicroRNAs have a crucial part to play in maintaining bone formation, signaling, and repair. This research explored the involvement miR-138-5p in modulating osteoblast differentiation in femoral fractures model.

METHODS

The role of mir-138-5p in the healing process of femoral fractures in rats was assessed through micro computed tomography (CT) imaging. After that, qPCR was employed to identify the cellular mRNA expression levels of miR-138-5p, SIRT1, and FoxO1 in either the callus or MC3T3-E1. Next, the protein expression level of Runx2, OPN, OCN and ALP was determined by western blot or ELISA. A dual-luciferase reporter gene assay was implemented to examine the target of miR-138-5p. The quantity of mineralized nodules was measured by means of alizarin red staining.

RESULTS

The miR-138-5p inhibitor promotes the mending of femoral fractures. When it is knocked down, the osteogenic differentiation is promoted, which may be caused by the enhanced activity of ALP and the elevation of the expression of Runx2, OPN and OCN. Meanwhile, an increase in the expression of mir-138-5p impairs the biosynthesis of SIRT1 and FoxO1. When SIRT1 and FoxO1 were downregulated with shRNA, the effect caused by the mir-138-5p inhibitor could be reversed.

CONCLUSION

Our studies uncovered that the overexpressed miR-138-5p might have an inhibitory role in femoral fractures healing by inactivating SIRT1/FOXO1 axis.

Apoptotic vesicles derived from bone marrow mesenchymal stem cells increase angiogenesis in a hind limb ischemia model via the NAMPT/SIRT1/FOXO1 axis

BACKGROUND

Chronic limb-threatening ischemia (CLTI) is the most severe form of peripheral arterial disease (PAD). Mesenchymal stem cell (MSC) transplantation holds promise as a treatment for CLTI; however, the harsh local environment poses challenges to its effectiveness. Apoptotic vesicles (ApoVs) are extracellular vesicles produced by cells undergoing apoptosis, and they can carry various biomolecules from their parent cells, including proteins, RNA, DNA, lipids, ions, and gas neurotransmitters. ApoVs play significant roles in anti-inflammatory responses, anti-tumor activities, and tissue regeneration through intercellular communication, and they have demonstrated potential as drug carriers. In this study, we investigated the potential of bone marrow stem cell (BMSC)-derived ApoVs for treating CLTI.

METHODS

In vivo, we explored the therapeutic effect of ApoVs on a hindlimb ischemia model through Laser Doppler, matrigel plug assay, and histological analysis. In vitro, we analyzed the effects of ApoVs on the proliferation, migration, and angiogenesis of HUVECs and explored the uptake process of ApoVs. In addition, Proteomic analysis, western blotting, quantitative real-time PCR, shRNA, and siRNA were used to analyze ApoVs-induced HUVECs activation and downstream signaling pathways.

RESULTS

BMSCs transplantation showed improvement in a hind limb ischemia model, and this effect still exists after apoptosis of BMSCs. Subsequently, ApoVs of BMSCs were isolated and found to improve mouse hind limb ischemia in vivo. In vitro, ApoVs can be ingested by HUVECs through dynamin-, clathrin-, and caveolin-mediated endocytosis and promote its proliferation, migration, and angiogenesis. Mechanistically, ApoVs transferred NAMPT to HUVECs, therefore activating the NAMPT/SIRT1/FOXO1 axis, influencing the transcriptional activity of FOXO1, and promoting angiogenesis.

CONCLUSIONS

Our results demonstrate that the transplanted BMSCs can ameliorate hindlimb ischemia by releasing ApoVs during apoptosis. The main mechanism of this effect is promoting the proliferation, migration, and angiogenesis of HUVECs through the NAMPT/SIRT1/FOXO1 axis. This study provides different insights into the therapeutic mechanisms through BMSCs and suggests a promising direction for ApoVs transplantation.

CLINICAL TRIAL NUMBER

Not applicable.

Porcine pericardial decellularized matrix bilayer patch containing adipose stem cell-derived exosomes for the treatment of diabetic wounds

Chronic hard-to-heal wounds pose a significant threat to patients' health and quality of life, and their clinical management remains a challenge. Adipose-derived stem cell exosomes (ADSC-exos) have shown promising results in promoting diabetic wound healing. However, effectively enhancing the retention of exosomes in wounds for treatment remains a key issue that needs to be addressed. There is a pressing need to develop new materials or methods to improve the bioavailability of exosomes. Porcine pericardium, an extracellular matrix-rich tissue, is easily obtainable and widely available. Decellularized porcine pericardium removes cellular components while retaining an extracellular matrix that supports cellular growth, making it an ideal raw material for preparing wound dressings. In this study, we developed porcine pericardial decellularized matrix bilayer patches loaded with ADSC-exos, which were transplanted into diabetic mouse skin wounds. Histological and immunohistochemical analyses revealed that these bilayer matrix patches accelerate wound healing by promoting granulation tissue formation, re-epithelialization, stimulating vascularization, and enhancing collagen production. In terms of the underlying biological mechanism, we found that decellularized extracellular matrix bilayer patches loaded with ADSC-exos enhanced the proliferation and migration of human dermal fibroblasts (HDFs) and HaCaT cells in vitro, and promoted tube formation in human umbilical vein endothelial cells (HUVECs). This research demonstrated that the porcine pericardial decellularized matrix is well-suited for exosome delivery and that these bilayer patches hold great potential in promoting diabetic wound healing, providing evidence to support the future clinical application of ADSC-exos.

Application of exosomes for the regeneration of skin wounds: Principles, recent applications and limitations

In the medical field, wound healing poses significant challenges due to its complexity and time-consuming nature. Cell-free wound repair, notably the utilization of exosomes (EXOs), has made significant progress in recent years. Urine, saliva, umbilical cord, blood, mesenchymal stem cells and breast milk cells can be used to extract and purify EXOs, which are Nano-sized lipid bilayer vesicles. Besides their relatively little toxicity, non-specific immunogenicity and excellent biocompatibility, EXOs also contain bioactive molecules such as proteins, lipids, microRNAs (miRNAs), and messenger RNAs (mRNAs). Their bioactive compounds have anti-inflammatory properties and can speed up wound healing. Various medicinal agents can also be contained within the EXOs. This review briefly provides new information on the different aspects of EXOs and evaluate the application of EXOs as a promising therapy in the regeneration of skin wounds in recent pre-clinical and clinical studies.

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.

Single-cell sequencing technology in skin wound healing

Skin wound healing is a complicated biological process that mainly occurs in response to injury, burns, or diabetic ulcers. It can also be triggered by other conditions such as dermatitis and melanoma-induced skin cancer. Delayed healing or non-healing after skin injury presents an important clinical issue; therefore, further explorations into the occurrence and development of wound healing at the cellular and molecular levels are necessary. Single-cell sequencing (SCS) is used to sequence and analyze the genetic messages of a single cell. Furthermore, SCS can accurately detect cell expression and gene sequences. The use of SCS technology has resulted in the emergence of new concepts pertaining to wound healing, making it an important tool for studying the relevant mechanisms and developing treatment strategies. This article discusses the application value of SCS technology, the effects of the latest research on skin wound healing, and the value of SCS technology in clinical applications. Using SCS to determine potential biomarkers for wound repair will serve to accelerate wound healing, reduce scar formation, optimize drug delivery, and facilitate personalized treatments.

Global trends in the clinical utilization of exosomes in dermatology: a bibliometric analysis

The arena of exosomal research presents substantial emerging prospects for clinical dermatology applications. This investigation conducts a thorough analysis of the contemporary global research landscape regarding exosomes and their implications for dermatological applications over the preceding decade. Employing bibliometric methodologies, this study meticulously dissects the knowledge framework and identifies dynamic trends within this specialized field. Contemporary scholarly literature spanning the last decade was sourced from the Web of Science Core Collection (WoSCC) database. Subsequent to retrieval, both quantitative and visual analyses of the pertinent publications were performed utilizing the analytical software tools VOSviewer and Citespace. A comprehensive retrieval yielded 545 scholarly articles dated from January 1, 2014, to December 31, 2023. Leading the research forefront are institutions such as Shanghai Jiao Tong University, The Fourth Military Medical University, and Sun Yat-sen University. The most prolific contributors on a national scale are China, the United States, and South Korea. Among the authors, Zhang Bin, Zhang Wei, and Zhang Yan emerge as the most published, with Zhang Bin also achieving the distinction of being the most cited. The International Journal of Molecular Sciences leads in article publications, whereas Stem Cell Research & Therapy holds the pinnacle in citation rankings. Theranostics boasts the highest impact factor among the periodicals. Current research hotspots in this area include Adipose mesenchymal stem cell-derived exosomes(ADSC-Exos), diabetic skin wounds, cutaneous angiogenesis, and the combination of biomaterials and exosomes. This manuscript constitutes the inaugural comprehensive bibliometric analysis that delineates the prevailing research trends and advancements in the clinical application of exosomes in dermatology. These analyses illuminate the contemporary research focal points and trajectories, providing invaluable insights that will inform further exploration within this domain.

The emerging modulators of non-coding RNAs in diabetic wound healing

Diabetic wound healing is a complex physiological process often hindered by the underlying metabolic dysfunctions associated with diabetes. Despite existing treatments, there remains a critical need to explore innovative therapeutic strategies to improve patient outcomes. This article comprehensively examines the roles of non-coding RNAs (ncRNAs), specifically microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), in regulating key phases of the wound healing process: inflammation, angiogenesis, re-epithelialization, and tissue remodeling. Through a deep review of current literature, we discuss recent discoveries of ncRNAs that have been shown to either promote or impair the wound healing process in diabetic wound healing, which were not covered in earlier reviews. This review highlights the specific mechanisms by which these ncRNAs impact cellular behaviors and pathways critical to each healing stage. Our findings indicate that understanding these recently identified ncRNAs provides new insights into their potential roles in diabetic wound healing, thereby contributing valuable knowledge for future research directions in this field.

The Angiogenic Repertoire of Stem Cell Extracellular Vesicles: Demystifying the Molecular Underpinnings for Wound Healing Applications

Stem cells-derived extracellular vesicles (SC-EVs) have emerged as promising therapeutic agents for wound repair, recapitulating the biological effects of parent cells while mitigating immunogenic and tumorigenic risks. These EVs orchestrate wound healing processes, notably through modulating angiogenesis-a critical event in tissue revascularization and regeneration. This study provides a comprehensive overview of the multifaceted mechanisms underpinning the pro-angiogenic capacity of EVs from various stem cell sources within the wound microenvironment. By elucidating the molecular intricacies governing their angiogenic prowess, we aim to unravel the mechanistic repertoire underlying their remarkable potential to accelerate wound healing. Additionally, methods to enhance the angiogenic effects of SC-EVs, current limitations, and future perspectives are highlighted, emphasizing the significant potential of this rapidly advancing field in revolutionizing wound healing strategies.

Mesenchymal stem cells in wound healing: A bibliometric analysis as a powerful research tool

Bibliographic analysis is still very rarely used in experimental basic study papers. The comprehensive bibliometric analysis of scientific literature on research progress and challenges in stem cell therapy for diabetic chronic wounds, which was conducted in the work of Shi et al can be a case study and a source of valuable information for writing reviews and experimental papers in this field. Basic experimental studies on a role of mesenchymal stem cells (MSCs) in wound healing that are published in 2023-2024, such as Zhang et al in 2023, Hu et al in 2023, Wang et al in 2023 are certainly also subjects for applying this powerful tool to analyze current research, challenges and perspectives in this field. This is due to the fact that these studies have addressed a great variety of aspects of the application of MSCs for the treatment of chronic wounds, such as using both the cells themselves and their various products: Sponges, hydrogels, exosomes, and genetic constructions. Such a wide variety of directions in the field of study and biomedical application of MSCs requires a deep understanding of the current state of research in this area, which can be provided by bibliometric analysis. Thus, the use of such elements of bibliographic analysis as publication count by year and analysis of top-10 keywords calculated independently or cited from bibliometric analysis studies can be safely recommended for every basic study manuscripts, primarily for the "Introduction" section, and review.

Recent Progress in Mesenchymal Stem Cell-Derived Exosomes for Skin Wound Repair

BACKGROUND

Exosomes are nanometer-sized, lipid bilayer membrane vesicles that are secreted by various cell types. Mesenchymal stem cells (MSCs) have been shown to exert therapeutic effects through the secretion of exosomes via a paracrine pathway. Functions: Recent studies have demonstrated that MSC-derived exosomes (MSC-Exos) can effectively transport various bioactive substances, including proteins, mRNAs, microRNAs, long non-coding RNAs, circular RNAs, and lipids, into target cells. This process regulates multiple aspects during wound repair, such as the inflammatory response, cell proliferation, migration, differentiation, angiogenesis, and matrix remodeling.

POTENTIAL APPLICATIONS

By promoting wound healing and inhibiting scar formation, MSC-Exos have shown great promise for clinical applications in wound repair. This review highlights the recent advances in our understanding of the role and mechanism of MSC-Exos during wound repair, providing insights into their potential use in future therapeutic strategies.

The Expression of Circ-Astn1 Inhibits High Glucose Induced Endothelial Progenitor Cell Dysfunction by Activating Autophagy

BACKGROUND

Diabetes mellitus (DM) and complications such as chronic kidney disease and cardiovascular symptoms pose a substantial public health burden. Increasing studies have shown that circular RNAs (circRNAs) regulate many gene expressions that are essential in diverse pathological and biological procedures. However, the roles of particular circRNAs in DM are unclear.

METHODS

In the current investigation, endothelial progenitor cells (EPCs) were used to search for abnormal expression of circRNAs by using high-throughput sequencing under high glucose (HG) conditions. The regulatory mechanisms and targets were then studied through bioinformatics analysis, luciferase reporter analysis, angiogenic differentiation experiments, flow cytometry detection of apoptosis and RT-qPCR analysis.

RESULTS

The circ-Astn1 expression in EPCs decreased after HG treatment. Overexpression or circ-Astn1 suppressed HG induced endothelial cell damage. MicroRNA (miR)-138-5p and SIRT5 were found to be the downstream targets of circ-Astn1 through luciferase reporter analysis. SIRT5 downregulation or miR-138-5p overexpression reversed circ-Astn1's protective effect against HG induced endothelial cell dysfunction, including apoptosis and abnormal vascular differentiation. Furthermore, circ-Astn1 overexpression promoted autophagy activation by increasing SIRT5 expression under HG conditions. Our findings suggest that circ-Astn1 mediated promotion of SIRT5 facilitates autophagy by sponging miR-138-5p.

CONLUSION

Together, our findings show that the overexpression of circ-Astn1 suppresses HG induced endothelial cell damage by targeting miR-138-5p/SIRT5 axis.

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.

Adipose-Derived Stem Cell Exosomes Facilitate Diabetic Wound Healing: Mechanisms and Potential Applications

Wound healing in diabetic patients is frequently hampered. Adipose-derived stem cell exosomes (ADSC-eoxs), serving as a crucial mode of intercellular communication, exhibit promising therapeutic roles in facilitating wound healing. This review aims to comprehensively outline the molecular mechanisms through which ADSC-eoxs enhance diabetic wound healing. We emphasize the biologically active molecules released by these exosomes and their involvement in signaling pathways associated with inflammation modulation, cellular proliferation, vascular neogenesis, and other pertinent processes. Additionally, the clinical application prospects of the reported ADSC-eoxs are also deliberated. A thorough understanding of these molecular mechanisms and potential applications is anticipated to furnish a theoretical groundwork for combating diabetic wound healing.

Adipose stem cell-derived exosomes promote wound healing by regulating the let-7i-5p/GAS7 axis

BACKGROUND

Injury to skin tissue is devastating for human health, making it imperative to devise strategies for hastening wound healing. Normal wound healing is a complex process comprising overlapping steps, including hemostasis, inflammatory response, proliferation, and matrix remodeling. This study investigated the effects of adipose stem cell-derived exosomes (ADSC-exos) on wound healing and the underlying mechanisms.

METHODS

In vitro hydrogen peroxide (H2O2)-treated human keratinocyte (HaCaT) cell lines and in vivo animal wound models were established for this purpose. The cell migration was assessed using transwell and wound healing assays, while exosome biomarker expressions were studied using western blot. Moreover, adipose stem cells were identified using flow cytometry, alizarin red S and oil red O staining, and transmission electron microscopy.

RESULTS

Results indicated that H2O2 treatment inhibited the cell viability and migration of HaCaT cells while being promoted by ADSC-exos. Mechanistic investigations revealed that microRNA-let-7i-5p (let-7i-5p) in ADSC-exos was carried into the HaCaT cells, inhibiting the expression of growth arrest-specific-7 (GAS7). Rescue experiments further verified these results, which indicated that GAS7 overexpression reversed the effect of let-7i-5p on the viability and migration of HaCaT cells, suggesting ADSC-exos promoted wound healing via the let-7i-5p/GAS7 axis.

CONCLUSION

Adipose stem cell-derived-exos enhanced the viability and migration of HaCaT via carrying let-7i-5p and targeting GAS7, ultimately promoting wound healing in rats.

SIRT1 activation promotes bone repair by enhancing the coupling of type H vessel formation and osteogenesis

Bone repair is intricately correlated with vascular regeneration, especially of type H vessels. Sirtuin 1 (SIRT1) expression is closely associated with endothelial function and vascular regeneration; however, the role of SIRT1 in enhancing the coupling of type H vessel formation with osteogenesis to promote bone repair needs to be investigated. A co-culture system combining human umbilical vein endothelial cells and osteoblasts was constructed, and a SIRT1 agonist was used to evaluate the effects of SIRT1 activity. The angiogenic and osteogenic capacities of the co-culture system were examined using short interfering RNA. Mouse models with bone defects in the femur or mandible were established to explore changes in type H vessel formation and bone repair following modulated SIRT1 activity. SIRT1 activation augmented the angiogenic and osteogenic capacities of the co-culture system by activating the PI3K/AKT/FOXO1 signalling pathway and did not significantly regulate osteoblast differentiation. Inhibition of the PI3K/AKT/FOXO1 pathway attenuated SIRT1-mediated effects. The SIRT1 activity in bone defects was positively correlated with the formation of type H vessels and bone repair in vivo, whereas SIRT1 inhibition substantially weakened vascular and bone formation. Thus, SIRT1 is crucial to the coupling of type H vessels with osteogenesis during bone repair.

Stem Cell-Derived Extracellular Vesicles: Promising Therapeutic Opportunities for Diabetic Wound Healing

Wound healing is a sophisticated and orderly process of cellular interactions in which the body restores tissue architecture and functionality following injury. Healing of chronic diabetic wounds is difficult due to impaired blood circulation, a reduced immune response, and disrupted cellular repair mechanisms, which are often associated with diabetes. Stem cell-derived extracellular vesicles (SC-EVs) hold the regenerative potential, encapsulating a diverse cargo of proteins, RNAs, and cytokines, presenting a safe, bioactivity, and less ethical issues than other treatments. SC-EVs orchestrate multiple regenerative processes by modulating cellular communication, increasing angiogenesis, and promoting the recruitment and differentiation of progenitor cells, thereby potentiating the reparative milieu for diabetic wound healing. Therefore, this review investigated the effects and mechanisms of EVs from various stem cells in diabetic wound healing, as well as their limitations and challenges. Continued exploration of SC-EVs has the potential to revolutionize diabetic wound care.

Exosomes as biomarkers and therapy in type 2 diabetes mellitus and associated complications

Type 2 diabetes mellitus (T2DM) is one of the most prevalent metabolic disorders worldwide. However, T2DM still remains underdiagnosed and undertreated resulting in poor quality of life and increased morbidity and mortality. Given this ongoing burden, researchers have attempted to locate new therapeutic targets as well as methodologies to identify the disease and its associated complications at an earlier stage. Several studies over the last few decades have identified exosomes, small extracellular vesicles that are released by cells, as pivotal contributors to the pathogenesis of T2DM and its complications. These discoveries suggest the possibility of novel detection and treatment methods. This review provides a comprehensive presentation of exosomes that hold potential as novel biomarkers and therapeutic targets. Additional focus is given to characterizing the role of exosomes in T2DM complications, including diabetic angiopathy, diabetic cardiomyopathy, diabetic nephropathy, diabetic peripheral neuropathy, diabetic retinopathy, and diabetic wound healing. This study reveals that the utilization of exosomes as diagnostic markers and therapies is a realistic possibility for both T2DM and its complications. However, the majority of the current research is limited to animal models, warranting further investigation of exosomes in clinical trials. This review represents the most extensive and up-to-date exploration of exosomes in relation to T2DM and its complications.