Hypoxia adipose stem cell-derived exosomes promote high-quality healing of diabetic wound involves activation of PI3K/Akt pathways

Innovative Treatment Strategies to Accelerate Wound Healing: Trajectory and Recent Advancements

Wound healing is highly specialized dynamic multiple phase process for the repair of damaged/injured tissues through an intricate mechanism. Any failure in the normal wound healing process results in abnormal scar formation, and chronic state which is more susceptible to infections. Chronic wounds affect patients’ quality of life along with increased morbidity and mortality and are huge financial burden to healthcare systems worldwide, and thus requires specialized biomedical intensive treatment for its management. The clinical assessment and management of chronic wounds remains challenging despite the development of various therapeutic regimens owing to its painstakingly long-term treatment requirement and complex wound healing mechanism. Various conventional approaches such as cell therapy, gene therapy, growth factor delivery, wound dressings, and skin grafts etc., are being utilized for promoting wound healing in different types of wounds. However, all these abovementioned therapies are not satisfactory for all wound types, therefore, there is an urgent demand for the development of competitive therapies. Therefore, there is a pertinent requirement to develop newer and innovative treatment modalities for multipart therapeutic regimens for chronic wounds. Recent developments in advanced wound care technology includes nanotherapeutics, stem cells therapy, bioengineered skin grafts, and 3D bioprinting-based strategies for improving therapeutic outcomes with a focus on skin regeneration with minimal side effects. The main objective of this review is to provide an updated overview of progress in therapeutic options in chronic wounds healing and management over the years using next generation innovative approaches. Herein, we have discussed the skin function and anatomy, wounds and wound healing processes, followed by conventional treatment modalities for wound healing and skin regeneration. Furthermore, various emerging and innovative strategies for promoting quality wound healing such as nanotherapeutics, stem cells therapy, 3D bioprinted skin, extracellular matrix-based approaches, platelet-rich plasma-based approaches, and cold plasma treatment therapy have been discussed with their benefits and shortcomings. Finally, challenges of these innovative strategies are reviewed with a note on future prospects.

Nanobiotechnology: Applications in Chronic Wound Healing

Wounds occur when skin integrity is broken and the skin is damaged. With progressive changes in the disease spectrum, the acute wounds caused by mechanical trauma have been become less common, while chronic wounds triggered with aging, diabetes and infection have become more frequent. Chronic wounds now affect more than 6 million people in the United States, amounting to 10 billion dollars in annual expenditure. However, the treatment of chronic wounds is associated with numerous challenges. Traditional remedies for chronic wounds include skin grafting, flap transplantation, negative-pressure wound therapy, and gauze dressing, all of which can cause tissue damage or activity limitations. Nanobiotechnology — which comprises a diverse array of technologies derived from engineering, chemistry, and biology — is now being applied in biomedical practice. Here, we review the design, application, and clinical trials for nanotechnology-based therapies for chronic wound healing, highlighting the clinical potential of nanobiotechnology in such treatments. By summarizing previous nanobiotechnology studies, we lay the foundation for future wound care via a nanotech-based multifunctional smart system.

Exosomal miR-17-5p from adipose-derived mesenchymal stem cells inhibits abdominal aortic aneurysm by suppressing TXNIP-NLRP3 inflammasome

Background

Preclinical studies have suggested that adipose-derived mesenchymal stem cells (ADSCs) transplantation can suppress abdominal aortic inflammation and aneurysm expansion through paracrine factors. Yet, the mechanism of action is not fully understood. In the present study, we further examined the function and mechanism of ADSC-derived exosomes (ADSC-exos) and their microRNA-17-5p (miR-17-5p) on the abdominal aortic aneurysm (AAA) progression.

Methods

ADSC-exos were isolated and identified. DiR and PKH67 staining were used to trace ADSC-exo in vivo and in vitro. Raw264.7 cells were applied to perform in vitro experiments, while a murine AAA model induced using angiotensin II (Ang II) was used for in vivo testing. The expression level of miR-17-5p in macrophages and Ang II-treated macrophages after ADSC-exos treatment was determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The target relation between miR-17-5p and thioredoxin-interacting protein (TXNIP) was identified by a dual-luciferase reporter gene assay. Artificial activation and block of experiments of miR-17-5p and TXNIP were conducted to clarify their functions in inflammation during AAA progression. The severity of AAA between groups was assessed by maximal aorta diameter, AAA incidence, survival rate, and histological stainings. Besides, inflammasome-related proteins and macrophage pyroptosis were further evaluated using western blot, RT-qPCR, and enzyme-linked immunosorbent assay (ELISA).

Results

The ADSC-exos were isolated and identified. In vivo testing showed that ADSC-exos were mainly distributed in the liver. Meanwhile, in vitro experiments suggested that ADSC-derived exosomes were taken up by macrophages, while inside, ADSC-exos miR-17-5p decreased a TXNIP induced by Ang II by directly binding to its 3′-untranslated region (3’UTR). Furthermore, overexpression of miR-17-5p enhanced the therapeutic function of ADSC-exos on inflammation during AAA expansion in vivo, while its inhibition reversed this process. Finally, overexpressed TXNIP triggered macrophage pyroptosis and was alleviated by ADSC-derived exosomes in vitro.

Conclusion

ADSC-exos miR-17-5p regulated AAA progression and inflammation via the TXNIP-NLRP3 signaling pathway, thus providing a novel insight in AAA treatment.

Role of hypoxia preconditioning in therapeutic potential of mesenchymal stem-cell-derived extracellular vesicles

The use of mesenchymal stem-cells (MSC) in cell therapy has received considerable attention because of their properties. These properties include high expansion and differentiation in vitro, low immunogenicity, and modulation of biological processes, such as inflammation, angiogenesis and hematopoiesis. Curiously, the regenerative effect of MSC is partly due to their paracrine activity. This has prompted numerous studies, to investigate the therapeutic potential of their secretome in general, and specifically their extracellular vesicles (EV). The latter contain proteins, lipids, nucleic acids, and other metabolites, which can cause physiological changes when released into recipient cells. Interestingly, contents of EV can be modulated by preconditioning MSC under different culture conditions. Among them, exposure to hypoxia stands out; these cells respond by activating hypoxia-inducible factor (HIF) at low O₂ concentrations. HIF has direct and indirect pleiotropic effects, modulating expression of hundreds of genes involved in processes such as inflammation, migration, proliferation, differentiation, angiogenesis, metabolism, and cell apoptosis. Expression of these genes is reflected in the contents of secreted EV. Interestingly, numerous studies show that MSC-derived EV conditioned under hypoxia have a higher regenerative capacity than those obtained under normoxia. In this review, we show the implications of hypoxia responses in relation to tissue regeneration. In addition, hypoxia preconditioning of MSC is being evaluated as a very attractive strategy for isolation of EV, with a high potential for clinical use in regenerative medicine that can be applied to different pathologies.

ADSC-exo@MMP-PEG smart hydrogel promotes diabetic wound healing by optimizing cellular functions and relieving oxidative stress

Diabetic wound complications are financially costly and difficult to heal in worldwide. Whereas the therapies of diabetic wound, such as wound dressing, endocrine therapy or flap-transplantations, were not satisfied. Based on our previous study of exosome secreted by adipose-derived stem cell (ADSC-exo), we loaded ADSC-exo into the matrix metalloproteinase degradable polyethylene glycol (MMP-PEG) smart hydrogel. Physical and chemical properties of ADSC-exo@MMP-PEG smart hydrogel were tested by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), weight loss examination, etc. As the hydrogel degraded in response to MMP, ADSC-exo was released and subsequently enhanced cell function via Akt signaling. Moreover, treatment with ADSC-exo@MMP-PEG smart hydrogel significantly relieved the H₂O₂-induced oxidative stress, which was widely recognized as a major cause of diabetic wound nonhealing. Similar results were achieved in mice diabetic wound models, in which the ADSC-exo@MMP-PEG treatment group displayed a significantly accelerated wound healing. To summarize, the present smart hydrogel with enzyme-response and exosome-release was proved to be benefit for diabetic wounds healing, which provides a reliable theoretical basis for application of ADSC-exo in treatment of diabetic wounds.

•

Loading ADSC-exo into PEG formed a smart hydrogel.

•

The smart hydrogel delivered exosome in response to MMP-2.

•

The smart hydrogel promoted diabetic wound healing by optimizing cellular functions.

The Therapeutic Role of ADSC-EVs in Skin Regeneration

Large skin defects caused by burns, unhealing chronic wounds, and trauma, are still an intractable problem for clinicians and researchers. Ideal skin regeneration includes several intricate and dynamic stages of wound repair and regeneration of skin physiological function. Adipose-derived stem cells (ADSCs), a type of mesenchymal stem cells (MSCs) with abundant resources and micro-invasive extraction protocols, have been reported to participate in each stage of promoting skin regeneration via paracrine effects. As essential products secreted by ADSCs, extracellular vesicles (EVs) derived from ADSCs (ADSC-EVs) inherit such therapeutic potential. However, ADSC-EVs showed much more clinical superiorities than parental cells. ADSC-EVs carry various mRNAs, non-coding RNAs, proteins, and lipids to regulate the activities of recipient cells and eventually accelerate skin regeneration. The beneficial role of ADSCs in wound repair has been widely accepted, while a deep comprehension of the mechanisms of ADSC-EVs in skin regeneration remains unclear. In this review, we provided a basic profile of ADSC-EVs. Moreover, we summarized the latest mechanisms of ADSC-EVs on skin regeneration from the aspects of inflammation, angiogenesis, cell proliferation, extracellular matrix (ECM) remodeling, autophagy, and oxidative stress. Hair follicle regeneration and skin barrier repair stimulated by ADSC-EVs were also reviewed. The challenges and prospects of ADSC-EVs-based therapies were discussed at the end of this review.

Identification of active compounds and molecular mechanisms of Dalbergia tsoi Merr.et Chun to accelerate wound healing

As a traditional Chinese medicine, Dalbergia tsoi Merr.et Chun (JZX) has been used for the treatment of wounds since ancient times. However, the active compounds and molecular mechanisms of JZX in the acceleration of wound healing are still unknown. Herein, we explored the main active compounds and key molecular mechanisms by which JZX accelerates wound healing. The ethanol extract of JZX was subjected to UPLC-Q-Orbitrap HRMS analysis to identify the main compounds. The pharmacological effect of JZX on wound healing was evaluated using a mouse excision wound model. Network pharmacology was utilized to predict the effective compounds and related signal transduction pathways of JZX that were involved in accelerating wound healing. The predicted key signaling pathways were then validated by immunohistochemical analysis. Interactions between the active compounds and therapeutic targets were confirmed by molecular docking analysis. JZX accelerated wound healing, improved tissue quality, and inhibited inflammation and oxidative stress. Moreover, our results suggested that the active components of JZX, such as butin, eriodyctiol, and formononetin, are the key compounds that facilitate wound treatment. Our studies also indicated that JZX accelerated wound healing by regulating the PI3K/Akt signaling pathway and inducing the expression of TGF-β1, FGF2, VEGFA, ECM1, and α-SMA at different stages of skin wound healing. The JZX extract accelerates wound healing by reducing inflammation and inhibiting oxidative stress, regulating the PI3K/Akt signaling pathway, and promoting the expression of growth factors, suggesting that JZX has potential clinical applicability in wound treatment.

Mesenchymal stem cell-derived exosomes: A novel and potential remedy for cutaneous wound healing and regeneration

Poor healing of cutaneous wounds is a common medical problem in the field of traumatology. Due to the intricate pathophysiological processes of wound healing, the use of conventional treatment methods, such as chemical molecule drugs and traditional dressings, have been unable to achieve satisfactory outcomes. Within recent years, explicit evidence suggests that mesenchymal stem cells (MSCs) have great therapeutic potentials on skin wound healing and regeneration. However, the direct application of MSCs still faces many challenges and difficulties. Intriguingly, exosomes as cell-secreted granular vesicles with a lipid bilayer membrane structure and containing specific components from the source cells may emerge to be excellent substitutes for MSCs. Exosomes derived from MSCs (MSC-exosomes) have been demonstrated to be beneficial for cutaneous wound healing and accelerate the process through a variety of mechanisms. These mechanisms include alleviating inflammation, promoting vascularization, and promoting proliferation and migration of epithelial cells and fibroblasts. Therefore, the application of MSC-exosomes may be a promising alternative to cell therapy in the treatment of cutaneous wounds and could promote wound healing through multiple mechanisms simultaneously. This review will provide an overview of the role and the mechanisms of MSC-derived exosomes in cutaneous wound healing, and elaborate the potentials and future perspectives of MSC-exosomes application in clinical practice.

Preconditioning and Engineering Strategies for Improving the Efficacy of Mesenchymal Stem Cell-Derived Exosomes in Cell-Free Therapy

Mesenchymal stem cells (MSCs) have been widely applied to regenerative medicine owing to their multiple differentiation, self-renewal, and immunomodulatory abilities. Exosomes are cell-secreted natural nanovesicles and thought to be mediators of intercellular communication and material transport. The therapeutic potential of MSCs can be largely attributed to MSC-derived exosomes (MSC-exosomes). Emerging evidence suggests that the therapeutic efficacy of MSC-exosomes is highly dependent on the status of MSCs, and optimization of the extracellular environment affects the exosomal content. Pretreatment methods including three-dimensional cultures, hypoxia, and other biochemical cues have been shown to potentially enhance the biological activity of MSC-exosomes while maintaining or enhancing their production. On the other hand, engineering means to enhance the desired function of MSC-exosomes has been rapidly gaining attention. In particular, biologically active molecule encapsulation and membrane modification can alter or enhance biological functions and targeting of MSC-exosomes. In this review, we summarize two possible strategies to improve the therapeutic activity of MSC-exosomes: preconditioning approaches and engineering exosomes. We also explore the underlying mechanisms of different strategies and discuss their advantages and limitations of the upcoming clinical applications.

Hypoxic mesenchymal stem cell-derived extracellular vesicles ameliorate renal fibrosis after ischemia-reperfusion injure by restoring CPT1A mediated fatty acid oxidation

BACKGROUND

Renal fibrosis is a common pathological process of chronic kidney diseases induced by multiple factors. Hypoxic pretreatment of mesenchymal stem cells can enhance the efficacy of secreted extracellular vesicles (MSC-EVs) on various diseases, but it is not clear whether they can better improve renal fibrosis. The latest research showed that recovery of fatty acid oxidation (FAO) can reduce renal fibrosis. In this study, we aimed to examine whether hypoxic pretreatment with MSC extracellular vesicles (Hypo-EVs) can improve FAO to restore renal fibrosis and to investigate the underlying mechanism.

METHODS

Hypo-EVs were isolated from hypoxia-pretreated human placenta-derived MSC (hP-MSC), and Norm-EVs were isolated from hP-MSC cultured under normal conditions. We used ischemia-reperfusion (I/R)-induced renal fibrosis model in vivo. The mice were injected with PBS, Hypo-EVs, or Norm-EVs immediately after the surgery and day 1 postsurgery. Renal function, kidney pathology, and renal fibrosis were assessed for kidney damage evaluation. For mechanistic exploration, fatty acid oxidation (FAO), mitochondrial morphological alterations, ATP production and mitochondrial mass proteins were detected in vivo. Mitochondrial membrane potential and reactive oxygen species (ROS) production were investigated in vitro.

RESULTS

We found that Hypo-EVs confer a superior therapeutic effect on recovery of renal structure damage, restoration of renal function and reduction in renal fibrosis. Meanwhile, Hypo-EVs enhanced mitochondrial FAO in kidney by restoring the expression of a FAO key rate-limiting enzyme carnitine palmitoyl-transferase 1A (CPT1A). Mechanistically, the improvement of mitochondrial homeostasis, characterized by repaired mitochondrial structure, restoration of mitochondrial mass and ATP production, inhibition of oxidative stress, and increased mitochondrial membrane potential, partially explains the effect of Hypo-EVs on improving mitochondrial FAO and thus attenuating I/R damage.

CONCLUSIONS

Hypo-EVs suppress the renal fibrosis by restoring CPT1A-mediated mitochondrial FAO, which effects may be achieved through regulation of mitochondrial homeostasis. Our findings provide further mechanism support for development cell-free therapy of renal fibrosis.

Adipose stem cells-released extracellular vesicles as a next-generation cargo delivery vehicles: a survey of minimal information implementation, mass production and functional modification

OBJECTIVES

To investigate current situation of minimal information implementation highlighted by minimal information for studies of extracellular vesicles 2018 (MISEV2018) guidelines, and explore technological advances towards mass production and functional modification in aesthetic, plastic and reconstructive surgery.

METHODS

Original articles on extracellular vesicles (EVs) of adipose stem cells (ASCs) were identified. Statistics upon minimal information for EVs research, such as species, cell types, culture conditions, conditioned media harvesting parameters, EVs isolation/storage/identification/quantification, functional uptake and working concentration, were analyzed.

RESULTS

The items of cell culture conditions such as passage number, seeding density, conditioned media harvesting time, functional uptake and working concentration were poorly documented, with a reporting percentage of 47.13%, 54.02%, 29.89%, 62.07% and 36.21%, respectively. However, there were some studies not reporting information of ASCs origin, culture medium, serum, EVs isolation methods, quantification and identification of EVs, accounting for 3.45%, 10.34%, 6.90%, 3.45%, 18.39% and 4.02%, respectively. Serum deprivation and trophic factors stimuli were attempted for EVs mass production. Several technological advances towards functional modification included hypoxia pre-condition, engineering EVs and controlled release. Presently, ASCs EVs have been applied in multiple fields, including diabetic/non-diabetic wound healing, angiogenesis, inflammation modulation, fat grafting, hair regeneration, antiaging, and healing and regeneration of cartilage/bone/peripheral nerve/tendon.

CONCLUSION

Our results highlight normative reporting of ASCs EVs in functional studies to increase reliability and reproducibility of scientific publications. The advances towards mass production and functional modification of ASCs EVs are also recommended to enhance therapeutic effects.

Hypoxia Induced Changes of Exosome Cargo and Subsequent Biological Effects

Exosomes are small extracellular vesicles that are secreted by almost all types of cells and exist in almost all extracellular spaces. As an important mediator of intercellular communication, exosomes encapsulate the miRNA, lncRNA, cirRNA, mRNA, cytokine, enzyme, lipid, and other components from the cytoplasm into its closed single membrane structure and transfer them to recipient units in an autocrine, paracrine, or endocrine manner. Hypoxia is a state of low oxygen tension and is involved in many pathological processes. Hypoxia influences the size, quantity, and expression of exosome cargos. Exosomes derived from hypoxic tumor cells transfer genetics, proteins, and lipids to the recipient units to exert pleiotropic effects. Different donor cells produce different cargo contents, target different recipient units and lead to different biological effects. Hypoxic exosomes derived from tumor cells uptaken by normoxic tumor cells lead to promoted proliferation, migration, and invasion; uptaken by extracellular space or liver lead to promoted metastasis; uptaken by endothelial cells lead to promoted angiogenesis; uptaken by immune cells lead to promoted macrophage polarization and changed tumor immune microenvironment. In addition to various types of tumors, hypoxic exosomes also participate in the development of diseases in the cardiovascular system, neuron system, respiratory system, hematology system, endocrine system, urinary system, reproduction system, and skeletomuscular system. Understanding the special characteristics of hypoxic exosomes provide new insight into elaborating the pathogenesis of hypoxia related disease. This review summarizes hypoxia induced cargo changes and the biological effects of hypoxic exosomes in tumors and non-malignant diseases in different systems.

miR-199a-5p Plays a Pivotal Role on Wound Healing via Suppressing VEGFA and ROCK1 in Diabetic Ulcer Foot

Diabetes mellitus (DM) is a growing health problem. As a common complication of DM, diabetic foot ulcer (DFU) results in delayed wound healing and is a leading cause of nontraumatic amputation. miR-199a-5p, a short noncoding RNA, had abnormal expression in DFU wound tissues. The expression of miR-199a-5p was significantly increased in DFU wound tissues, skin tissues of diabetic rats, and high glucose-induced cells. Vascular endothelial growth factor A (VEGFA) and Rho-associated kinase 1 (ROCK1) are directly targets of miR-199a-5p. Inhibiting the expression of miR-199a-5p alleviated the inhibition of VEGFA and ROCK1, thereby rescued impaired proliferation and migration of HG-induced cells, and restored the normal function of the cells to some extent. In diabetic rats, inhibition of miR-199a-5p significantly increased the expression of VEGFA and ROCK1, significantly promoted wound healing, and rescued impaired wound healing. miR-199a-5p and its targets showed therapeutic effect on diabetic wounds.

Hypoxic pretreatment of adipose-derived stem cell exosomes improved cognition by delivery of circ-Epc1 and shifting microglial M1/M2 polarization in an Alzheimer's disease mice model

Alzheimer's disease (AD) is the most common dementia in the world. Increasing evidence has shown that exosomes from hypoxic pretreated adipose-derived stem cells (ADSCs) could be an effective cognitive function therapeutic in AD-associated pathophysiology. However, their role and regulatory mechanism remain largely unknown. High-throughput sequencing was used to identify differentially expressed circRNAs from ADSCs or hypoxia pretreated ADSC exosomes. Luciferase reporter assays and RT-qPCR were used to investigate the relationships between circ-Epc1, miR-770-3p, and TREM2. APP/PS1 double transgenic AD model mice were then used to study therapeutic effects regarding circ-Epc1 in ADSC exosomes. BV2 cells were used to show the regulatory relationships between circ-Epc1, miR-770-3p, and TREM2 and to show how these interactions modulated phenotypic transformations and inflammatory cytokine expressions in microglia. The results showed that exosomes from hypoxia pretreated ADSCs had a good therapeutic effect on improving cognitive functions by decreasing neuronal damage in the hippocampus. High-throughput sequencing showed that circ-Epc1 played an important role in hypoxia-pretreated ADSC exosomes regarding their ability to improve cognitive functions. Luciferase reporter assays showed that TREM2 and miR-770-3p were downstream targets of circ-Epc1. Overexpressing miR-770-3p or downregulating TREM2 reversed the effects of circ-Epc1 on M2 microglia during lipopolysaccharide treatment. In vivo experiments showed that circ-Epc1-containing ADSC exosomes increased the therapeutic effect of exosomes by improving cognitive function, decreasing neuronal damage, and shifting hippocampal microglia from the M1 polarization to the M2 polarization stages. Taken together, the data show that hypoxic pretreatment of ADSC exosomes improved cognition by delivery of circ-Epc1 and by shifting microglial M1/M2 polarization in an AD mouse model.

Roles of MicroRNA-21 in Skin Wound Healing: A Comprehensive Review

MicroRNA-21 (miR-21), one of the early mammalian miRNAs identified, has been detected to be upregulated in multiple biological processes. Increasing evidence has demonstrated the potential values of miR-21 in cutaneous damage and skin wound healing, but lack of a review article to summarize the current evidence on this issue. Based on this review, relevant studies demonstrated that miR-21 played an essential role in wound healing by constituting a complex network with its targeted genes (i.e., PTEN, RECK. SPRY1/2, NF-κB, and TIMP3) and the cascaded signaling pathways (i.e., MAPK/ERK, PI3K/Akt, Wnt/β-catenin/MMP-7, and TGF-β/Smad7-Smad2/3). The treatment effectiveness developed by miR-21 might be associated with the promotion of the fibroblast differentiation, the improvement of angiogenesis, anti-inflammatory, enhancement of the collagen synthesis, and the re-epithelialization of the wound. Currently, miRNA nanocarrier systems have been developed, supporting the feasibility clinical feasibility of such miR-21-based therapy. After further investigations, miR-21 may serve as a potential therapeutic target for wound healing.

Curcumin primed ADMSCs derived small extracellular vesicle exert enhanced protective effects on osteoarthritis by inhibiting oxidative stress and chondrocyte apoptosis

Osteoarthritis (OA) is a common joint disease caused by progressive articular cartilage degeneration and destruction. Currently, there are no disease-modifying agents officially approved for OA patients. In this study, curcumin was loaded into adipose tissue-derived mesenchymal stem cells (ADMSCs)-derived small extracellular vesicle (ADMSCs-sEV) to synergistically exert chondro-protective effects in vitro and in vivo. We found curcumin primed ADMSCs derived sEV (sEV-CUR) exhibited an enhanced protective effect compared with free curcumin and ADMSCs-sEV in TBHP-induced chondrocytes. Moreover, our study demonstrated sEV-CUR more effectively down-regulated TBHP-induced oxidative stress and chondrocyte apoptosis in vitro. In OA mice model, our results indicated that sEV-CUR showed an improved cartilage protection, as biweekly intra-articular injection of sEV-CUR more efficaciously alleviated oxidative stress and chondrocyte apoptosis in OA cartilage. Overall, our findings showed sEV-CUR exhibited enhanced chondro-protective effects and holds great potential on the recovery of articular cartilage loss and destruction in OA patients.

pH-switchable nanozyme cascade catalysis: a strategy for spatial-temporal modulation of pathological wound microenvironment to rescue stalled healing in diabetic ulcer

The management of diabetic ulcer (DU) to rescue stalled wound healing remains a paramount clinical challenge due to the spatially and temporally coupled pathological wound microenvironment that features hyperglycemia, biofilm infection, hypoxia and excessive oxidative stress. Here we present a pH-switchable nanozyme cascade catalysis (PNCC) strategy for spatial–temporal modulation of pathological wound microenvironment to rescue stalled healing in DU. The PNCC is demonstrated by employing the nanozyme of clinically approved iron oxide nanoparticles coated with a shell of glucose oxidase (Fe₃O₄-GOx). The Fe₃O₄-GOx possesses intrinsic glucose oxidase (GOx), catalase (CAT) and peroxidase (POD)-like activities, and can catalyze pH-switchable glucose-initiated GOx/POD and GOx/CAT cascade reaction in acidic and neutral environment, respectively. Specifically, the GOx/POD cascade reaction generating consecutive fluxes of toxic hydroxyl radical spatially targets the acidic biofilm (pH ~ 5.5), and eradicates biofilm to shorten the inflammatory phase and initiate normal wound healing processes. Furthermore, the GOx/CAT cascade reaction producing consecutive fluxes of oxygen spatially targets the neutral wound tissue, and accelerates the proliferation and remodeling phases of wound healing by addressing the issues of hyperglycemia, hypoxia, and excessive oxidative stress. The shortened inflammatory phase temporally coupled with accelerated proliferation and remodeling phases significantly speed up the normal orchestrated wound-healing cascades. Remarkably, this Fe₃O₄-GOx-instructed spatial–temporal remodeling of DU microenvironment enables complete re-epithelialization of biofilm-infected wound in diabetic mice within 15 days while minimizing toxicity to normal tissues, exerting great transformation potential in clinical DU management. The proposed PNCC concept offers a new perspective for complex pathological microenvironment remodeling, and may provide a powerful modality for the treatment of microenvironment-associated diseases.

Exosomes for diabetes syndrome: ongoing applications and perspective

Diabetes mellitus, ranking the ninth death cause in the world, is a kind of metabolic disease characterized by hyperglycemia. Without timely and effective treatment, many ensuing complications involved with heart,...

The roles of mesenchymal stem cell-derived exosomes in diabetes mellitus and its related complications

Diabetes mellitus is a type of metabolic disease characterized by hyperglycemia, primarily caused by defects in insulin secretion, insulin action, or both. Long-term chronic hyperglycemia can lead to diabetes-related complications, causing damage, dysfunction, and failure of different organs. However, traditional insulin and oral drug therapy can only treat the symptoms but not delay the progressive failure of pancreatic beta cells or prevent the emergence of diabetic complications. Mesenchymal stem cells have received extensive attention due to their strong immunoregulatory functions and regeneration effects. Mesenchymal stem cell-derived exosomes (MSC-Exos) have been proposed as a novel treatment for diabetic patients as they have demonstrated superior efficiency to mesenchymal stem cells. This review summarizes the therapeutic effects, mechanisms, challenges, and future prospects of MSC-Exos in treating diabetes mellitus and its related complications. This review supports the potential use of MSC-Exos in future regenerative medicine to overcome the current difficulties in clinical treatment, particularly in treating diabetes.

Cell secretomes for wound healing and tissue regeneration: Next generation acellular based tissue engineered products

Wound represents a significant socioeconomic burden for both affected individuals and as a whole healthcare system. Accordingly, stem cells have garnered attention due to their differentiation capacity and ability to aid tissue regeneration by releasing biologically active molecules, found in the cells’ cultivated medium which known as conditioned medium (CM) or secretomes. This acellular approach provides a huge advantage over conventional treatment options, which are mainly used cellular treatment at wound closure. Interestingly, the secretomes contained the cell-secreted proteins such as growth factors, cytokines, chemokines, extracellular matrix (ECM), and small molecules including metabolites, microvesicles, and exosomes. This review aims to provide a general view on secretomes and how it is proven to have great potential in accelerating wound healing. Utilizing the use of secretomes with its secreted proteins and suitable biomaterials for fabrications of acellular skin substitutes can be promising in treating skin loss and accelerate the healing process.

Extracellular Vesicles from HIF-1α-Overexpressing Adipose-Derived Stem Cells Restore Diabetic Wounds Through Accelerated Fibroblast Proliferation and Migration

PURPOSE

Inhibition of cellular adaptation to hypoxia can cause persistent inflammation, thereby increasing tissue damage and complicating wound healing in diabetes patients. Regulating cellular adaptation to hypoxic environments can help in effective wound repair. Hypoxia-inducible factor (HIF)-1α is a key regulator of cell hypoxia. Extracellular vesicles (EVs) regulate wound repair. This study investigated the mechanism of HIF-1α overexpression in adipose-derived stem cell extracellular vesicles (ADSCs-hEVs) in the repair of diabetic wounds.

MATERIALS AND METHODS

HIF-1α expression in diabetes patients and healthy participants was studied. High-throughput sequencing, GO, and KEGG analysis revealed that ADSCs small extracellular vesicle hypoxia environments may increase HIF-1α expression by affecting cell metabolism, differentiation, and TGF-β secretion, or by altering the PI3K/AKT pathway. Effect of addition of ADSCs-hEVs on cell proliferation and migration was investigated using Western blotting, EdU assay, transwell assay, and migration. In vivo, after 7, 14, and 21 days, important factors for diabetic wound healing were evaluated by immunohistochemistry, qRT-PCR, Masson staining, and H&E staining.

RESULTS

HIF-1α expression decreased in the skin of diabetes patients; interleukin (IL)-6 expression increased, and growth factor-related indexes decreased. ADSCs-hEVs significantly increased the expression and secretion of growth factors, compared with ADSCs-EVs. In vivo, ADSC-hEV treatment accelerated the healing rate and improved the healing quality of diabetic wounds compared with ADSCs-EVs.

CONCLUSION

Speed and quality of wound healing increased significantly in the ADSCs-hEVs group, which could inhibit early inflammation while promoting the secretion and expression of growth factors and extracellular matrix-related indexes.

Hemin enhances the cardioprotective effects of mesenchymal stem cell-derived exosomes against infarction via amelioration of cardiomyocyte senescence

BACKGROUND

Application of mesenchymal stem cell-derived exosomes (MSC-EXO) has emerged as a novel therapeutic strategy for myocardial infarction (MI). Our previous study showed that pretreatment with hemin, a potent heme oxygenase-1 (HO-1) inducer, enhanced the cardioprotective effects of MSCs in a mouse model of MI. This study aimed to investigate the therapeutic effects of EXO derived from hemin-pretreated MSCs (Hemin-MSC-EXO) in MI and explore the potential mechanisms.

METHODS

MSC-EXO and Hemin-MSC-EXO were collected and characterized. MSC-EXO and Hemin-MSC-EXO were intramuscularly injected into the peri-infarct region in a mouse model of MI. Heart function of mice was assessed by echocardiography. The mitochondrial morphology of neonatal mice cardiomyocytes (NMCMs) under serum deprivation and hypoxic (SD/H) conditions was examined by Mitotracker staining. The cellular senescence of NMCMs was determined by senescence-associated-β-galactosidase assay. A loss-of-function approach was adopted to determine the role of Hemin-MSC-exosomal-miR-183-5p in the regulation of cardiomyocyte senescence RESULTS: EXO were successfully isolated from the supernatant of MSCs and Hemin-pretreated MSCs. Compared with MSC-EXO, injection of Hemin-MSC-EXO significantly improved cardiac function and reduced fibrosis. Both MSC-EXO and Hemin-MSC-EXO ameliorated cardiomyocyte senescence and mitochondrial fission in vitro and in vivo, and the latter exhibited better protective effects. MicroRNA sequencing revealed a higher level of miR-183-5p in Hemin-MSC-EXO than in MSC-EXO. MiR-183-5p knockdown partially abrogated the protective effects of Hemin-MSC-EXO in attenuating mitochondrial fission and cellular senescence of cardiomyocytes induced by SD/H. High mobility group box-1 (HMGB1) abundance was lower in Hemin-MSC-EXO-treated than MSC-EXO-treated mouse hearts, and HMGB1 was identified as one of the potential target genes of miR-183-5p. Mechanistically, Hemin-MSC-EXO inhibited SD/H-induced cardiomyocyte senescence partially by delivering miR-183-5p into recipient cardiomyocytes via regulation of the HMGB1/ERK pathway. Furthermore, knockdown of miR-183-5p reduced the Hemin-MSC-EXO-mediated cardioprotective effects in a mouse model of MI.

CONCLUSION

Our results reveal that Hemin-MSC-EXO are superior to MSC-EXO in treating MI. Exosomal miR-183-5p mediates, at least partially, the cardioprotective effects of Hemin-MSC-EXO by inhibiting cardiomyocyte senescence via regulation of the HMGB1/ERK pathway. This study highlights that MSC-EXO have high translational value in repairing cardiac dysfunction following infarction.

Mesenchymal Stem Cell-Derived Exosomes and Their Potential Agents in Hematological Diseases

Mesenchymal stem cells (MSCs) are the most exploited stem cells with multilineage differentiation potential and immunomodulatory properties. Numerous lines of findings have reported their successful applications in a multitude of inflammatory conditions and immune disorders. However, it is currently discovered that these effects are mainly mediated in a paracrine manner by MSC-exosomes. Moreover, MSC-exosomes have been implicated in a wide variety of biological responses including immunomodulation, oxidative stress, tumor progression, and tissue regeneration. Meanwhile, they are reported to actively participate in various hematological diseases by the means of transferring different types of exosomal components to the target cells. Therefore, in this review, we briefly discuss the sources and biological features of MSCs and then illustrate the biogenesis and biological processes of MSC-exosomes. Of note, this paper especially highlights the latest research progress of MSC-exosomes in hematological diseases.

Extracellular Vesicles: Emerging Therapeutics in Cutaneous Lesions

Extracellular vesicles (EVs), as nanoscale membranous vesicles containing DNAs, RNAs, lipids and proteins, have emerged as promising diagnostic and therapeutic agents for skin diseases. Here, we summarize the basic physiology of the skin and the biological characteristic of EVs. Further, we describe the applications of EVs in the treatment of dermatological conditions such as skin infection, inflammatory skin diseases, skin repair and rejuvenation and skin cancer. In particular, plant-derived EVs and clinical trials are discussed. In addition, challenges and perspectives related to the preclinical and clinical applications of EVs are highlighted.