The functions and clinical application potential of exosomes derived from adipose mesenchymal stem cells: a comprehensive review

Stem cells part of the innate and adaptive immune systems as a therapeutic for Covid-19

Some stem cell types not only release molecules that reduce viral replication, but also reduce the hypercytokinemia and inflammation induced by the immune system, and have been found to be part of the innate and adaptive immune systems. An important component of the stem cell's ability to ameliorate viral diseases, especially the complications post-clearance of the pathogen, is the ability of adult stem cells to reset the innate and adaptive immune systems from an inflammatory state to a repair state. Thus, the molecules released from certain stem cell types found to be safe and efficacious, may be an important new means for therapeutic development in Covid-19, especially for late-stage inflammation and tissue damage once the virus has cleared, particularly in the aged population.

Nanotherapeutic approach to tackle chemotherapeutic resistance of cancer stem cells

Estimates indicate that cancer will become the leading cause of mortality worldwide in the future. Tumorigenesis is a complex process that involves self-sufficiency in signs of growth, insensitivity to anti-growth signals, prevention of apoptosis, unlimited replication, sustained angiogenesis, tissue invasion, and metastasis. Cancer stem cells (CSCs) have an important role in tumor development and resistance. Here we will approach phenotypic plasticity capacity, highly efficient DNA repair systems, anti-apoptotic machinery, sustained stemness features, interaction with the tumor microenvironment, and Notch, Wnt, and Hedgehog signaling pathways. The researches about CSCs as a target in cancer treatment has been growing. Many different options have pointed beneficial results, such as pathways and CSC-surface markers targeting. Besides its limitations, nanotherapeutics have emerged as a potential strategy in this context since they aim to improve pharmacokinetics, biodistribution, and reduce the side effects observed in traditional treatments. Nanoparticles have been studied in this field, mostly for drug delivery and a multitherapy approach. Another widely researched approaches in this area are related to heat therapy, such as photothermal therapy, photodynamic therapy and magnetic hyperthermia, besides molecular targeting. This review will contemplate the most relevant studies that have shown the effects of nanotherapeutics. In conclusion, although the studies analyzed are mostly preclinical, we believe that there is strong evidence that nanoparticles can increase the chances of a better prognosis to cancer in the future. It is also essential to transpose these findings to the clinic to confirm and better understand the role of nanotherapeutics in this context.

Small extracellular vesicles from menstrual blood-derived mesenchymal stem cells (MenSCs) as a novel therapeutic impetus in regenerative medicine

Menstrual blood-derived mesenchymal stem cells (MenSCs) have great potential in regenerative medicine. MenSC has received increasing attention owing to its impressive therapeutic effects in both preclinical and clinical trials. However, the study of MenSC-derived small extracellular vesicles (EVs) is still in its initial stages, in contrast to some common MSC sources (e.g., bone marrow, umbilical cord, and adipose tissue). We describe the basic characteristics and biological functions of MenSC-derived small EVs. We also demonstrate the therapeutic potential of small EVs in fulminant hepatic failure, myocardial infarction, pulmonary fibrosis, prostate cancer, cutaneous wound, type-1 diabetes mellitus, aged fertility, and potential diseases. Subsequently, novel hotspots with respect to MenSC EV-based therapy are proposed to overcome current challenges. While complexities regarding the therapeutic potential of MenSC EVs continue to be unraveled, advances are rapidly emerging in both basic science and clinical medicine. MenSC EV-based treatment has great potential for treating a series of diseases as a novel therapeutic strategy in regenerative medicine.

Scaffold strategies combined with mesenchymal stem cells in vaginal construction: a review

Tissue engineering has provided new treatment alternatives for tissue reconstruction. Advances in the tissue engineering field have resulted in mechanical support and biological substitutes to restore, maintain or improve tissue/organs structures and functions. The application of tissue engineering technology in the vaginal reconstruction treatment can not only provide mechanical requirements, but also offer tissue repairing as an alternative to traditional approaches. In this review, we discuss recent advances in cell-based therapy in combination with scaffolds strategies that can potentially be adopted for gynaecological transplantation.

Bone marrow-mesenchymal stem cell-derived exosomal microRNA-141 targets PTEN and activates β-catenin to alleviate myocardial injury in septic mice

BACKGROUND

Mesenchymal stem cells (MSCs) and their derived exosomes have shown potentials in the control of myocardial dysfunction. This study aimed to reveal the function of bone marrow (BM)-MSC-derived exosomes in sepsis-induced myocardial injury and the molecular mechanism.

METHODS

BM-MSC-derived exosomes were obtained and identified. A mouse model with sepsis was induced by cecalligation puncture (CLP) and treated with exosomes. The myocardial function of mice, the production of creatine kinase MB (CK-MB) and lactate dehydrogenase (LDH) in serum, the phosphorylation of a key myocardial contractility-related protein phospholamban (PLB), and the pathological changes in the myocardial tissues were examined. A microRNA (miRNA) microarray analysis was performed to examine the candidate miRNAs carried by the exosomes. Rescue experiments were conducted to validate the involvement of miR-141.

RESULTS

CLP treatment led to sepsis and notably reduced the myocardial function in mice. Further treatment of BM-MSC-derived exosomes alleviated the CLP-induced myocardial impairment, production of CK-MB and LDH, and inflammatory infiltration and cell apoptosis in mouse myocardial tissues, and restored the PLB phosphorylation. miR-141 was the most upregulated miRNA in the myocardial tissues after exosome treatment. Downregulation of miR-141 blocked the myocardium-protective functions of the exosomes. miR-141 was found to bind to and suppress PTEN expression, which further enhanced the activity of β-catenin.

CONCLUSION

This study suggested that BM-MSC derived exosomes ameliorates myocardial injury in septic mice through conveying miRNA-141 and regulating the PTEN/β-catenin axis, and exosomes may serve as promising tools for the management of myocardial injury induced by sepsis or other factors.

Extracellular vesicles derived from DFO-preconditioned canine AT-MSCs reprogram macrophages into M2 phase

Background

Mesenchymal stem/stromal cells (MSCs) are effective therapeutic agents that ameliorate inflammation through paracrine effect; in this regard, extracellular vesicles (EVs) have been frequently studied. To improve the secretion of anti-inflammatory factors from MSCs, preconditioning with hypoxia or hypoxia-mimetic agents has been attempted and the molecular changes in preconditioned MSC-derived EVs explored. In this study, we aimed to investigate the increase of hypoxia-inducible factor 1-alpha (HIF-1α)/cyclooxygenase-2 (COX-2) in deferoxamine (DFO)-preconditioned canine MSC (MSC^DFO) and whether these molecular changes were reflected on EVs. Furthermore, we focused on MSC^DFO derived EVs (EV^DFO) could affect macrophage polarization via the transfer function of EVs.

Results

In MSC^DFO, accumulation of HIF-1α were increased and production of COX-2 were activated. Also, Inside of EV^DFO were enriched with COX-2 protein. To evaluate the transferring effect of EVs to macrophage, the canine macrophage cell line, DH82, was treated with EVs after lipopolysaccharide (LPS) stimulation. Polarization changes of DH82 were evaluated with quantitative real-time PCR and immunofluorescence analyses. When LPS-induced DH82 was treated with EV^DFO, phosphorylation of signal transducer and transcription3 (p-STAT3), which is one of key factor of inducing M2 phase, expression was increased in DH82. Furthermore, treated with EV^DFO in LPS-induced DH82, the expression of M1 markers were reduced, otherwise, M2 surface markers were enhanced. Comparing with EV^DFO and EV^non.

Conclusion

DFO preconditioning in MSCs activated the HIF-1α/COX-2 signaling pathway; Transferring COX-2 through EV^DFO could effectively reprogram macrophage into M2 phase by promoting the phosphorylation of STAT3.

Exosomes as Part of the Human Adipose-Derived Stem Cells Secretome- Opening New Perspectives for Cell-Free Regenerative Applications

Human adipose-derived stem cells (hASCs) represent a great resource for regenerative medicine based on their accessibility, self-renewal potential, low immunogenicity, high proliferative rate and potential to differentiate on multiple lineages. Their secretome is rich in chemokines, cytokines and protein growth factors that are actively involved in regeneration processes. In addition, part of this secretome are also the exosomes (hASC-exos), which display high content in proteins, messenger RNAs (mRNAs) and non-coding RNAs (ncRNAs). Due to their content, exosomes promote tissue regeneration by different mechanisms, either by activating or inhibiting several signaling pathways involved in wound healing, extracellular matrix remodeling, immunomodulation, angiogenesis, anti-apoptotic activity and cell migration, proliferation and differentiation. The use of hASC-exos may provide an improved alternative to standard therapies used in regenerative medicine, as a cell-free new approach with multiple possibilities to be modulated according to the patient needs. This review offers an updated overview on the functions and applications of hASC-exos in all areas of tissue regeneration, aiming to highlight to the reader the benefits of using hASCs in modern tissue engineering and regenerative medicine applications.

Adipose tissue versus stem cell-derived small extracellular vesicles to enhance the healing of acute burns

Aim: Proper healing of extensive burns remains a healthcare challenge. In the present study, we proposed a distinct therapeutic application of adipose tissue and small extracellular vesicles isolated from human menstrual blood-derived mesenchymal stem cells (MenSC) small extracellular vesicles (sEVs) to enhance the repair of third-degree burn injury. Materials & methods: Mouse model of third-degree burn was used. Adipose tissue in the form of nano-fat (NF) and MenSC-sEVs was injected subcutaneously at the site of injuries. Results: NF and sEVs were capable of enhancing wound closure and increasing neoangiogenesis. NF was also effective in accelerating the formation of granulation tissue and boosting the thickness of the new epithelial layer. Conclusion: This study demonstrates the effectiveness of NF and MenSC-sEVs as promising therapeutic approaches to facilitate the repair of skin burns.

Identification and characterization of hADSC-derived exosome proteins from different isolation methods

Exosomes are secreted into the extracellular space by most cell types and contain various molecular constituents, which play roles in many biological processes. Adipose-derived mesenchymal stem cells (ADSCs) can differentiate into a variety of cell types and secrete a series of paracrine factors through exosomes. ADSC-derived exosomes have shown diagnostic and therapeutic potential in many clinical diseases. The molecular components are critical for their mechanisms. Several methods have been developed for exosome purification, including ultracentrifugation, ultrafiltration, density gradient purification, size-based isolation, polymer precipitation and immuno-affinity purification. Thus, we employed four methods to isolate exosomes from the hADSC culture medium, including ultracentrifugation, size exclusion chromatography, ExoQuick-TC precipitation and ExoQuick-TC ULTRA isolation. Following exosome isolation, we performed quantitative proteomic analysis of the exosome proteins using isobaric tags for relative and absolute quantification (iTRAQ) labelling, combined with 2D-LC-MS/MS. There were 599 universal and 138 stably expressed proteins in hADSC-derived exosomes. We proved that these proteins were potential hADSC-derived exosomes markers, including CD109, CD166, HSPA4, TRAP1, RAB2A, RAB11B and RAB14. From the quantitative proteomic analysis, we demonstrated that hADSC-derived exosome protein expression varied, with lipopolysaccharide (LPS) treatment, in the different isolation methods. Pathway analysis and proliferation, migration and endothelial tube formation assays showed varying effects in cells stimulated with hADSC-derived exosomes from different isolation methods. Our study revealed that different isolation methods might introduce variations in the protein composition in exosomes, which reflects their effects on biological function. The pros and cons of these methods are important points to consider for downstream research applications.

Exosomes derived from human umbilical cord mesenchymal stem cells alleviate acetaminophen-induced acute liver failure through activating ERK and IGF-1R/PI3K/AKT signaling pathway

This study aimed to investigate the therapeutic potential of human umbilical cord mesenchymal stem cells derived exosomes (hUCMSC-Exo) in acute liver failure (ALF) in mice as well as its underlying mechanism. We found that a single tail vein administration of hucMSC-Exo effectively enhanced the survival rate, inhibited apoptosis in hepatocytes, and improved liver function in APAP-induced mouse model of ALF. Furthermore, the deletion of glutathione (GSH) and superoxide dismutase (SOD), generation of malondialdehyde (MDA), and the over production of cytochrome P450 E1 (CYP2E1) and 4-hydroxynonenal (4-HNE) caused by APAP were also inhibited by hucMSC-Exo, indicating that hucMSC-Exo inhibited APAP-induced apoptosis of hepatocytes by reducing oxidative stress. Moreover, hucMSC-Exo significantly down-regulated the levels of inflammatory cytokines IL-6, IL-1β, and TNF-α in APAP-treated livers. Western blot showed that hucMSC-Exo significantly promoted the activation of ERK1/2 and IGF-1R/PI3K/AKT signaling pathways in APAP-injured LO2 cells, resulting in the inhibition of apoptosis of LO2 cells. Importantly, PI3K inhibitor LY294002 and ERK1/2 inhibitor PD98059 could reverse the function of hucMSC-Exo on APAP-injured LO2 cells in some extent. Our results suggest that hucMSC-Exo offer antioxidant hepatoprotection against APAP in vitro and in vivo by inhibitiing oxidative stress-induced apoptosis via upregulation of ERK1/2 and PI3K/AKT signaling pathways.

Human acellular amniotic membrane incorporating exosomes from adipose-derived mesenchymal stem cells promotes diabetic wound healing

Background

Diabetic wounds threaten the health and quality of life of patients and their treatment remains challenging. ADSC-derived exosomes have shown encouraging results in enhancing diabetic wound healing. However, how to use exosomes in wound treatment effectively is a problem that needs to be addressed at present.

Methods

A diabetic mouse skin wound model was established. ADSC-derived exosomes (ADSC-Exos) were isolated, and in vitro application of exosomes was evaluated using human umbilical vein endothelial cells (HUVECs) and human dermal fibroblasts (HDFs). After preparation and characterization of a scaffold of human acellular amniotic membrane (hAAM) loaded with ADSC-Exos in vitro, they were transplanted into wounds in vivo and wound healing phenomena were observed by histological and immunohistochemical analyses to identify the wound healing mechanism of the exosome-hAAM composites.

Results

The hAAM scaffold dressing was very suitable for the delivery of exosomes. ADSC-Exos enhanced the proliferation and migration of HDFs and promoted proliferation and tube formation of HUVECs in vitro. In vivo results from a diabetic skin wound model showed that the hAAM-Exos dressing accelerated wound healing by regulating inflammation, stimulating vascularization, and promoting the production of extracellular matrix.

Conclusion

Exosome-incorporated hAAM scaffolds showed great potential in promoting diabetic skin wound healing, while also providing strong evidence for the future clinical applications of ADSC-derived exosomes.

Extracellular Vesicles from Human Adipose-Derived Mesenchymal Stem Cells: A Review of Common Cargos

In recent years, the interest in adipose tissue mesenchymal cell–derived extracellular vesicles (AT-MSC-EVs) has increasingly grown. Numerous articles support the potential of human AT-MSC-EVs as a new therapeutic option for treatment of diverse diseases in the musculoskeletal and cardiovascular systems, kidney, skin, and immune system, among others. This approach makes use of the molecules transported inside of EVs, which play an important role in cell communication and in transmission of macromolecules. However, to our knowledge, there is no database where essential information about AT-MSC-EVs cargo molecules is gathered for easy reference. The aim of this study is to describe the different molecules reported so far in AT-MSC- EVs, their main molecular functions, and biological processes in which they are involved. Recently, the presence of 591 proteins and 604 microRNAs (miRNAs) has been described in human AT-MSC-EVs. The main molecular function enabled by both proteins and miRNAs present in human AT-MSC-EVs is the binding function. Signal transduction and gene silencing are the biological processes in which a greater number of proteins and miRNAs from human AT-MSC-EVs are involved, respectively. In this review we highlight the therapeutics effects of AT-MSC-EVs related with their participation in relevant biological processes including inflammation, angiogenesis, cell proliferation, apoptosis and migration, among others.

The Role of Adipose Stem Cells in Bone Regeneration and Bone Tissue Engineering

Bone regeneration is a complex process that is influenced by tissue interactions, inflammatory responses, and progenitor cells. Diseases, lifestyle, or multiple trauma can disturb fracture healing, which might result in prolonged healing duration or even failure. The current gold standard therapy in these cases are bone grafts. However, they are associated with several disadvantages, e.g., donor site morbidity and availability of appropriate material. Bone tissue engineering has been proposed as a promising alternative. The success of bone-tissue engineering depends on the administered cells, osteogenic differentiation, and secretome. Different stem cell types offer advantages and drawbacks in this field, while adipose-derived stem or stromal cells (ASCs) are in particular promising. They show high osteogenic potential, osteoinductive ability, and immunomodulation properties. Furthermore, they can be harvested through a noninvasive process in high numbers. ASCs can be induced into osteogenic lineage through bioactive molecules, i.e., growth factors and cytokines. Moreover, their secretome, in particular extracellular vesicles, has been linked to fracture healing. The aim of this review is a comprehensive overview of ASCs for bone regeneration and bone tissue engineering.

Adipose-Derived Mesenchymal Stem Cells-Derived Exosomes Carry MicroRNA-671 to Alleviate Myocardial Infarction Through Inactivating the TGFBR2/Smad2 Axis

Mesenchymal stem cells (MSCs) and their derived extracellular vesicles have been reported as promising tools for the management of heart disease. The aim of this study was to explore the function of adipose-derived MSCs (adMSCs)-derived exosomes (Exo) in the progression of myocardial infarction (MI) and the molecules involved. Mouse cardiomyocytes were treated with oxygen-glucose deprivation (OGD) to mimic an MI condition in vitro. The adMSCs-derived Exo were identified and administrated into the OGD-treated cardiomyocytes, and then the viability and apoptosis of cells, and the secretion of fibrosis- and inflammation-related cytokines in cells were determined. Differentially expressed microRNAs (miRNAs) in cells after Exo treatment were screened using a microarray analysis. The downstream molecules regulated by miR-671 were explored through bioinformatic analysis. Involvements of miR-671 and transforming growth factor beta receptor 2 (TGFBR2) in the exosome-mediated events were confirmed by rescue experiments. A murine model with MI was induced and treated with Exo for functional experiments in vivo. Compared to phosphate-buffered saline treatment, the Exo treatment significantly enhanced viability while reduced apoptosis of cardiomyocytes, and in reduced myocardial fibrosis and inflammation both in vitro and in vivo. miR-671 was significantly upregulated in cells after Exo treatment. Downregulation of miR-671 blocked the protective functions of Exo. miR-671 targeted TGFBR2 and suppressed phosphorylation of Smad2. Artificial downregulation of TGFBR2 enhanced viability of the OGD-treated cardiomyocytes. This study suggested that adMSC-derived exosomal miR-671 directly targets TGFBR2 and reduces Smad2 phosphorylation to alleviate MI-like symptoms both in vivo and in vitro.

Therapeutic potential of small extracellular vesicles derived from lipoma tissue in adipose tissue regeneration-an in vitro and in vivo study

OBJECTIVE

To explore the adipogenic effects of the small extracellular vesicles derived from the lipoma tissues (sEV-LT), and to find a new cell-free therapeutic approach for adipose tissue regeneration.

METHODS

Adipose tissue-derived stem cells (ADSCs) and small extracellular vesicles derived from the adipose tissues (sEV-AT) were isolated from human adipose tissue, while sEV-LT were isolated from human lipomatous tissue. ADSCs were characterized by using flow cytometric analysis and adipogenic and osteogenic differentiation assays. sEV was identified by electron microscopy, nanoparticle tracking, and western blotting. ADSCs were treated with sEV-LT and sEV-AT, respectively. Fluorescence confocal microscopy was used to investigate whether sEV-LT and sEV-AT could be taken by ADSCs. The proliferation and migration abilities and adipogenic differentiation assay of ADSCs were evaluated by CCK-8 assays, scratch test, and oil red O staining test, and the expression levels of adipogenic-related genes C/EBP-δ, PPARγ2, and Adiponectin in ADSCs were assessed by real-time quantitative PCR (RT-PCR). The sEV-LT and sEV-AT transplantation tubes were implanted subcutaneously in SD rats, and the neotissues were qualitatively and histologically evaluated at 2, 4, 8, and 12 weeks after transplantation. Hematoxylin and eosin (H&E) staining was subsequently used to observe and compare the adipogenesis and angiogenesis in neotissues, while immunohistochemistry was used to examine the expression and the distribution of C/EBP-α, PPARγ, Adiponectin, and CD31 at the 4th week.

RESULTS

The in vitro experiments showed that both sEV-LT and sEV-AT could be taken up by ADSCs via endocytosis. The scratch experiment and CCK-8 experiment showed that the migration area and proliferation number of ADSCs in sEV-LT group and sEV-AT group were significantly higher than those in the non-sEV group (p < 0.05). Compared with sEV-AT group, sEV-LT group had larger migration area and proliferation number of ADSCs (p < 0.05). Oil red O staining and RT-PCR experiments showed that, compared with the non-sEVs group, the lipid droplets and the mRNA expression levels of adipogenesis-related genes PPARγ2 and Adiponectin of ADSCs in sEV-LT group and sEV-AT group were significantly upregulated (p < 0.05); however, there was no statistical significance in the expression level of C/EBP-δ (p > 0.05). In addition, no significant difference in the amount of lipid droplets and adipogenesis-related genes between the sEV-LT groups and sEV-AT was seen (p > 0.05). At 2, 4, 8, and 12 weeks, the adipocyte area and the number of capillaries in neotissues in the sEV-LT groups and sEV-AT groups were significantly increased compared with the Matrigel group (p < 0.05); however, there was no dramatic difference between sEV-LT groups and sEV-AT groups (p > 0.05). At the 4th week, neotissues in the sEV-LT groups and sEV-AT groups all showed upregulated expression of C/EBP-α, PPARγ, Adiponectin, and CD31 protein, while neotissues in the Matrigel group only showed positive expression of CD31 protein.

CONCLUSIONS

This study demonstrated that sEV-LT exerted promotion effects on adipose tissue regeneration by accelerating the proliferation, migration, and adipogenic differentiation of ADSCs in vitro and recruiting adipocytes and promoting angiogenesis in vivo. The sEV-LT could serve as an alternative cell-free therapeutic strategy for generating adipose tissue, thus providing a promising application prospect in tissue engineering.

Beyond the Extracellular Vesicles: Technical Hurdles, Achieved Goals and Current Challenges When Working on Adipose Cells

Adipose tissue and its crosstalk with other organs plays an essential role in the metabolic homeostasis of the entire body. Alteration of this communication (i.e., due to obesity) is related to the development of several comorbidities including type 2 diabetes, cardiovascular diseases, or cancer. Within the adipose depot, adipocytes are the main cell type and thus the main source of secreted molecules, which exert modulating effects not only at a local but also at a systemic level. Extracellular vesicles (EVs) have recently emerged as important mediators in cell–cell communication and account for part of the cellular secretome. In recent years, there has been a growing body of research on adipocyte-derived extracellular vesicles (Ad-EVs). However, there is still a lack of standardized methodological approaches, especially regarding primary adipocytes. In this review, we will provide an outline of crucial aspects when working on adipose-derived material, with a special focus on primary adipocytes. In parallel, we will point out current methodological challenges in the EV field and how they impact the transcriptomic, proteomic and functional evaluations of Ad-EVs.

Exosomes from adipose-derived stem cells alleviate the inflammation and oxidative stress via regulating Nrf2/HO-1 axis in macrophages

ADSCs exosomes, an important means of intercellular communication, can regulate an array of biological processes, including promoting tissue repairs and regeneration, and attenuating inflammation. In this study, we found that ADSCs exosomes could polarize macrophage to an anti-inflammatory phenotype via regulating the expression of Nrf2 and HO-1, and improve inflammatory reaction and injury of multi-organ in sepsis. We revealed that ADSCs exosomes could alleviate LPS induced accumulation of ROS and the expression of inflammatory cytokines IL-1β, TNF-α, and IL-6 in macrophages. Western blot and Flow cytometry results indicated that expression of M1 markers (iNOS and CD86) in LPS stimulated macrophages were significantly declined, while M2 (Arg1 and CD206) were enhanced when pretreated with ADSCs exosomes. Besides, the stress-related molecule HO-1 was upregulated when pretreated with ADSCs exosomes. Further H0-1 interference experiment indicated that anti-inflammatory effect of ADSCs exosomes was dependent on HO-1. Moreover, ADSCs exosomes enhanced expression and nucleus translocation of Nrf2, while downregulated its negative mediator Keap1. In in vivo sepsis models, intravenous injection of ADSCs exosomes relieved inflammatory cytokines storm and organ injury, while promoted expression of HO-1. In conclusion, we proved that ADSCs exosomes alleviated LPS induced inflammation and exerted protective effect in sepsis via regulating Nrf2/HO-1 expression.

Administration of extracellular vesicles derived from human amniotic fluid stem cells: a new treatment for necrotizing enterocolitis

PURPOSE

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal disease. Amniotic fluid stem cells (AFSC) improve NEC injury but human translation remains difficult. We aimed to evaluate the use of extracellular vesicles (EV) derived from human AFSC.

METHODS

Human AFSC (hAFSC) were cultured according to the protocol (Celprogen Inc., California, U.S.A.). Conditioned medium was obtained, ultra-centrifuged, and EV were suspended in phosphate-buffered saline (PBS). C57BL/6 pups were grouped into: (1) breast-fed (Control, n = 11); (2) NEC + placebo (NEC + PBS; n = 10); and (3) NEC + treatment (NEC + EV; n = 11). NEC was induced post-natal days P5-9 by (A) gavage feeding hyperosmolar formula; (B) hypoxia for 10 min; and (C) lipopolysaccharide. Intra-peritoneal injections of PBS or hAFSC-EV were given on P6-7. All animals were sacrificed on P9 and terminal ileum harvested.

RESULTS

hAFSC-EV administration reduced intestinal injury (p = 0.0048), NEC incidence (score ≥ 2), and intestinal inflammation (IL-6 p < 0.0001; TNF-α p < 0.0001). Intestinal stem cell expression (Lgr5 +) and cellular proliferation (Ki67) were enhanced above control levels following hAFSC-EV administration (Lgr5 p = 0.0003; Ki67 p < 0.0001).

CONCLUSION

hAFSC-EV administration reduced intestinal NEC injury and inflammation while increasing stem cell expression and cellular proliferation. hAFSC-EV administration may induce similar beneficial effects to exogenous stem cells.

The novel mechanisms and applications of exosomes in dermatology and cutaneous medical aesthetics

Exposure to the external environment may lead to instability and dysfunction of the skin, resulting in refractory wound, skin aging, pigmented dermatosis, hair loss, some immune-mediated dermatoses, and connective tissue diseases. Nowadays, many skin treatments have not achieved a commendable balance between medical recovery and cosmetic needs. Exosomes are cell-derived nanoscale vesicles carrying various biomolecules, including proteins, nucleic acids, and lipids, with the capability to communicate with adjacent or distant cells. Recent studies have demonstrated that endogenic multiple kinds of exosomes are crucial orchestrators in shaping physiological and pathological development of the skin. Besides, exogenous exosomes, such as stem cell exosomes, can serve as novel treatment options to repair, regenerate, and rejuvenate skin tissue. Herein, we review new insights into the role of endogenic and exogenous exosomes in the skin microenvironment and recent advances in applications of exosomes related to dermatology and cutaneous medical aesthetics. The deep understanding of the mechanisms by which exosomes perform biological functions in skin is of great potential to establish attractive therapeutic methods for the skin.

Exosomes derived from miR-301a-3p-overexpressing adipose-derived mesenchymal stem cells reverse hypoxia-induced erectile dysfunction in rat models

Background

Erectile dysfunction (ED) has often been observed in patients with obstructive sleep apnea (OSA). Research on adipose-derived mesenchymal stem cell (ADSC)-derived exosomes has shown that they have significant therapeutic effects in many diseases including ED.

Methods

In this study, ED was induced in Sprague Dawley (SD) rats using chronic intermittent hypoxia (CIH) exposure. CIH-mediated influences were then measured in the corpus cavernous smooth muscle cells (CCSMCs).

Results

Our data showed that miR-301a-3p-enriched exosome treatment significantly recovered erectile function in rats and CCSMCs by promoting autophagy and inhibiting apoptosis. The treatment also significantly recovered the level of alpha smooth muscle actin (α-SMA) in rats and CCSMCs. Bioinformatics predicted that phosphatase and tensin homolog (PTEN) and Toll-like receptor 4 (TLR4) might be targets of miR-301a-3p.

Conclusions

Our results indicate that PTEN-overexpression vectors or TLR4-overexpression vectors reverse the therapeutic effects achieved by miR-301a-3p in CCSMCs indicating that PTEN/hypoxia-inducible factor-1 alpha (HIF-1α) and TLR4 signaling pathways play key roles in the progression of ED. The findings in this study suggest that miR-301a-3p should be considered a new therapeutic target for treating ED associated with OSA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02161-8.

Aesthetic and therapeutic outcome of fat grafting for localized Scleroderma treatment: From basic study to clinical application

BACKGROUND

Localized scleroderma (LoS) is a rare autoimmune disease characterized by skin fibrosis and subcutaneous tissue atrophy, resulting in aesthetic impairment on patients. Fat grafting has been used to treat LoS patients, achieving aesthetic and therapeutic improvement.

AIMS

This article summarized the epidemiology and pathophysiology of LoS and the current progress and thorny questions of basic and clinical research on fat grafting treating LoS.

METHODS

The literature of the last 20 years concerning fat grafting of treating LoS was reviewed.

RESULTS

Fat grafting has been proved to produce aesthetic and therapeutic outcomes on LoS patients, including the improvement of soft tissue atrophy, skin fibrosis and pigmentation. Due to the inflammatory microenvironment of scleroderma, however, fat grafting still faces many difficulties, such as low fat retention. Novel fat grafting methods in order to supplement the deficiency of adipose-derived stem cells and improve fat retention in LoS groups have been proposed whose effectiveness and feasibility is still needed further study.

CONCLUSION

Currently, fat grafting has been regarded as an effective treatment with a combination of aesthetic and therapeutic outcomes on LoS patients.

Therapeutic application of exosomes in ischaemic stroke

Ischaemic stroke is a leading cause of long-term disability in the world, with limited effective treatments. Increasing evidence demonstrates that exosomes are involved in ischaemic pathology and exhibit restorative therapeutic effects by mediating cell–cell communication. The potential of exosome therapy for ischaemic stroke has been actively investigated in the past decade. In this review, we mainly discuss the current knowledge of therapeutic applications of exosomes from different cell types, different exosomal administration routes, and current advances of exosome tracking and targeting in ischaemic stroke. We also briefly summarised the pathology of ischaemic stroke, exosome biogenesis, exosome profile changes after stroke as well as registered clinical trials of exosome-based therapy.

Neglected No More: Emerging Cellular Therapies in Traumatic Injury

Traumatic injuries are a leading cause of death and disability in both military and civilian populations. Given the complexity and diversity of traumatic injuries, novel and individualized treatment strategies are required to optimize outcomes. Cellular therapies have potential benefit for the treatment of acute or chronic injuries, and various cell-based pharmaceuticals are currently being tested in preclinical studies or in clinical trials. Cellular therapeutics may have the ability to complement existing therapies, especially in restoring organ function lost due to tissue disruption, prolonged hypoxia or inflammatory damage. In this article we highlight the current status and discuss future directions of cellular therapies for the treatment of traumatic injury. Both published research and ongoing clinical trials are discussed here.

Extracellular Vesicles from Adipose Tissue Stem Cells in Diabetes and Associated Cardiovascular Disease; Pathobiological Impact and Therapeutic Potential

Adipose tissue-derived stem cells (ADSCs) are pluripotent mesenchymal stem cells found in relatively high percentages in the adipose tissue and able to self-renew and differentiate into many different types of cells. “Extracellular vesicles (EVs), small membrane vesicular structures released during cell activation, senescence, or apoptosis, act as mediators for long distance communication between cells, transferring their specific bioactive molecules into host target cells”. There is a general consensus on how to define and isolate ADSCs, however, multiple separation and characterization protocols are being used in the present which complicate the results’ integration in a single theory on ADSCs’ and their derived factors’ way of action. Metabolic syndrome and type 2 diabetes mellitus (T2DM) are mainly caused by abnormal adipose tissue size, distribution and metabolism and so ADSCs and their secretory factors such as EVs are currently investigated as therapeutics in these diseases. Moreover, due to their relatively easy isolation and propagation in culture and their differentiation ability, ADSCs are being employed in preclinical studies of implantable devices or prosthetics. This review aims to provide a comprehensive summary of the current knowledge on EVs secreted from ADSCs both as diagnostic biomarkers and therapeutics in diabetes and associated cardiovascular disease, the molecular mechanisms involved, as well as on the use of ADSC differentiation potential in cardiovascular tissue repair and prostheses.

Obesity and Cancer Metastasis: Molecular and Translational Perspectives

Obesity is a modern health problem that has reached pandemic proportions. It is an established risk factor for carcinogenesis, however, evidence for the contribution of adipose tissue to the metastatic behavior of tumors is also mounting. Over 90% of cancer mortality is attributed to metastasis and metastatic tumor cells must communicate with their microenvironment for survival. Many of the characteristics observed in obese adipose tissue strongly mirror the tumor microenvironment. Thus in the case of prostate, pancreatic and breast cancer and esophageal adenocarcinoma, which are all located in close anatomical proximity to an adipose tissue depot, the adjacent fat provides an ideal microenvironment to enhance tumor growth, progression and metastasis. Adipocytes provide adipokines, fatty acids and other soluble factors to tumor cells whilst immune cells infiltrate the tumor microenvironment. In addition, there are emerging studies on the role of the extracellular vesicles secreted from adipose tissue, and the extracellular matrix itself, as drivers of obesity-induced metastasis. In the present review, we discuss the major mechanisms responsible for the obesity-metastatic link. Furthermore, understanding these complex mechanisms will provide novel therapies to halt the tumor-adipose tissue crosstalk with the ultimate aim of inhibiting tumor progression and metastatic growth.

Small extracellular vesicles (sEVs): discovery, functions, applications, detection methods and various engineered forms

INTRODUCTION

Extracellular vesicles (EVs) are cell-created delivery systems of proteins, lipids, or nucleic acids, and means of extracellular communication. Though sEVs were initially considered to be the waste disposal mechanism, today they are at the forefront of research with different biological and pathological functions. Such EVs play a key role in the immunoregulation, CNS development, nervous system physiology, mammary gland development, induction of immunosuppression in pregnancy, the developmental signaling pathways, regeneration of different tissues, inflammation, angiogenesis, coagulation, apoptosis, stem cell differentiation, and extracellular matrix turnover.

AREAS COVERED

SEVs contribute to the pathogenesis of different cancers and the progression of various neurodegenerative diseases, infections, as well as metabolic and cardiovascular diseases. Expert Opinion: There is no exact classification for EVs; however, according to size, density, morphological features, content, and biogenesis, they can be categorized into three major classes: microvesicles (ectosomes or microparticles), apoptotic bodies, and sEVs. SEVs, as an important class of EVs, have a crucial role in distinct biological functions. Moreover, shedding light on different structural and molecular aspects of sEV has led to their application in various therapeutic, diagnostic, and drug delivery fields. In this review, we have endeavored to elaborate on different aspects of EVs, especially sEVs.

Roles of Regulatory RNAs in Nutritional Control

Small RNAs (sRNAs), including microRNAs (miRNAs), are noncoding RNA (ncRNA) molecules involved in gene regulation. sRNAs play important roles in development; however, their significance in nutritional control and as metabolic modulators is still emerging. The mechanisms by which diet impacts metabolic genes through miRNAs remain an important area of inquiry. Recent work has established how miRNAs are transported in body fluids often within exosomes, which are small cell-derived vesicles that function in intercellular communication. The abundance of other recently identified ncRNAs and new insights regarding ncRNAs as dietary bioactive compounds could remodel our understanding about how foods impact gene expression. Although controversial, some groups have shown that dietary RNAs from plants and animals (i.e., milk) are functional in consumers. In the future, regulating sRNAs either directly through dietary delivery or indirectly by altered expression of endogenous sRNA may be part of nutritional interventions for regulating metabolism.

Adipose Mesenchymal Stem Cell-Derived Exosomal microRNA-1236 Reduces Resistance of Breast Cancer Cells to Cisplatin by Suppressing SLC9A1 and the Wnt/β-Catenin Signaling

BACKGROUND

Emerging evidence has noted the versatile functions of mesenchymal stem cell-derived exosomes (MSC-Exos) in cancer control. This work aims to probe to function of adipose MSC-Exos (adMSC-Exos) in drug-resistance of breast cancer (BC) cells to cisplatin (DDP) and the molecules involved.

METHODS

Parental and DDP-resistant BC cell lines MCF-7 and MDA-MB-231 were used. All cells were pre-treated with adMSC-Exos. Then, the viability and apoptosis of cells after DDP treatment were determined. Differentially expressed miRNAs after adMSC-exo treatment were screened out. Rescue experiments were conducted by pre-transfecting miR-1236 inhibitor into adMSCs, and the role of miR-1236 in DDP sensitivity was determined. Targeting mRNAs of miR-1236 were predicted by bioinformatics analysis. Altered SLC9A1 expression was administrated to evaluate its function in DDP resistance.

RESULTS

The adMSC-Exos notably increased the sensitivity of either parental or DDP-resistant BC cells to DDP. SLC9A1 was notably highly expressed in DDP-resistant cells but inhibited following adMSC-exo administration. Importantly, miR-1236, which could directly bind to SLC9A1 and suppress its expression, was confirmed as an enriched miRNA in adMSC-Exos. Either inhibition of miR-1236 or upregulation of SLC9A1 blocked the pro-sensitize roles of adMSC-Exos. In addition, the Wnt/β-catenin pathway activity was suppressed by adMSC-Exos but recovered by SLC9A1.

CONCLUSION

This study evidenced that adMSC-Exos carry miR-1236 to increase sensitivity of BC cells to DDP with the involvement of SLC9A1 downregulation and Wnt/β-catenin inactivation. This finding may offer novel insights into treatment for drug-resistant BC.

Extracellular Vesicles as Innovative Tool for Diagnosis, Regeneration and Protection against Neurological Damage

Extracellular vesicles (EVs) have recently attracted a great deal of interest as they may represent a new biosignaling paradigm. According to the mode of biogenesis, size and composition, two broad categories of EVs have been described, exosomes and microvesicles. EVs have been shown to carry cargoes of signaling proteins, RNA species, DNA and lipids. Once released, their content is selectively taken up by near or distant target cells, influencing their behavior. Exosomes are involved in cell–cell communication in a wide range of embryonic developmental processes and in fetal–maternal communication. In the present review, an outline of the role of EVs in neural development, regeneration and diseases is presented. EVs can act as regulators of normal homeostasis, but they can also promote either neuroinflammation/degeneration or tissue repair in pathological conditions, depending on their content. Since EV molecular cargo constitutes a representation of the origin cell status, EVs can be exploited in the diagnosis of several diseases. Due to their capability to cross the blood–brain barrier (BBB), EVs not only have been suggested for the diagnosis of central nervous system disorders by means of minimally invasive procedures, i.e., “liquid biopsies”, but they are also considered attractive tools for targeted drug delivery across the BBB. From the therapeutic perspective, mesenchymal stem cells (MSCs) represent one of the most promising sources of EVs. In particular, the neuroprotective properties of MSCs derived from the dental pulp are here discussed.

Exosomes From Adipose-Derived Stem Cells: The Emerging Roles and Applications in Tissue Regeneration of Plastic and Cosmetic Surgery

Adipose-derived stem cells (ASCs) are an important stem cell type separated from adipose tissue, with the properties of multilineage differentiation, easy availability, high proliferation potential, and self-renewal. Exosomes are novel frontiers of intercellular communication regulating the biological behaviors of cells, such as angiogenesis, immune modulation, proliferation, and migration. ASC-derived exosomes (ASC-exos) are important components released by ASCs paracrine, possessing multiple biological activities. Tissue regeneration requires coordinated “vital networks” of multiple growth factors, proteases, progenitors, and immune cells producing inflammatory cytokines. Recently, as cell-to-cell messengers, ASC-exos have received much attention for the fact that they are important paracrine mediators contributing to their suitability for tissue regeneration. ASC-exos, with distinct properties by encapsulating various types of bioactive cargoes, are endowed with great application potential in tissue regeneration, mechanically via the migration and proliferation of repair cells, facilitation of the neovascularization, and other specific functions in different tissues. Here, this article elucidated the research progress of ASC-exos about tissue regeneration in plastic and cosmetic surgery, including skin anti-aging therapy, dermatitis improvement, wound healing, scar removal, flap transplantation, bone tissue repair and regeneration, obesity prevention, fat grafting, breast cancer, and breast reconstruction. Deciphering the biological properties of ASC-exos will provide further insights for exploring novel therapeutic strategies of tissue regeneration in plastic and cosmetic surgery.

hADSCs derived extracellular vesicles inhibit NLRP3inflammasome activation and dry eye

The present study was set out to address the therapeutic efficacy of human adipose tissue stem cells derived extracellular vesicles (hADSC-Evs) in a mouse model of dry eye disease and to investigate the underlying mechanisms involved. hADSC-Evs eye drops were topically administered to mice that subjected to desiccating stress (DS). Clinical parameters of ocular surface damage were assessed with fluorescein staining, tear production and PAS staining. For in vitro studies, cell viability assay and TUNEL staining were performed in human corneal epithelial cells (HCECs) treated with hADSC-Evs under hyperosmotic media. In addition, immunofluorescent staining, Real-time PCR (qRT-PCR) and Western blots were used to evaluated NLRP3, ASC, caspase-1, and IL-1β expression levels. Compared with vehicle control mice, topical hADSC-Evs treated mice showed decreased corneal epithelial defects, increased tear production, decreased goblet cell loss, as well as reduced inflammatory cytokines production. In vitro, hADSC-Evs could protect HCECs against hyperosmotic stress-induced cell apoptosis. Mechanistically, hADSC-Evs treatment suppressed the DS induced rises in NLRP3 inflammasome formation, caspase-1 activation and IL-1β maturation. In conclusion, hADSC-Evs eye drops effectively suppress NLRP3 inflammatory response and alleviate ocular surface damage in dry eye disease.

Mesenchymal stem cell-derived exosomes: Toward cell-free therapeutic strategies in regenerative medicine

Mesenchymal stem cells (MSCs) are multipotent stem cells with marked potential for regenerative medicine because of their strong immunosuppressive and regenerative abilities. The therapeutic effects of MSCs are based in part on their secretion of biologically active factors in extracellular vesicles known as exosomes. Exosomes have a diameter of 30-100 nm and mediate intercellular communication and material exchange. MSC-derived exosomes (MSC-Exos) have potential for cell-free therapy for diseases of, for instance, the kidney, liver, heart, nervous system, and musculoskeletal system. Hence, MSC-Exos are an alternative to MSC-based therapy for regenerative medicine. We review MSC-Exos and their therapeutic potential for a variety of diseases and injuries.

Obesity and COVID-19: Molecular Mechanisms Linking Both Pandemics

The coronavirus disease 2019 COVID-19 pandemic is rapidly spreading worldwide and is becoming a major public health crisis. Increasing evidence demonstrates a strong correlation between obesity and the COVID-19 disease. We have summarized recent studies and addressed the impact of obesity on COVID-19 in terms of hospitalization, severity, mortality, and patient outcome. We discuss the potential molecular mechanisms whereby obesity contributes to the pathogenesis of COVID-19. In addition to obesity-related deregulated immune response, chronic inflammation, endothelium imbalance, metabolic dysfunction, and its associated comorbidities, dysfunctional mesenchymal stem cells/adipose-derived mesenchymal stem cells may also play crucial roles in fueling systemic inflammation contributing to the cytokine storm and promoting pulmonary fibrosis causing lung functional failure, characteristic of severe COVID-19. Moreover, obesity may also compromise motile cilia on airway epithelial cells and impair functioning of the mucociliary escalators, reducing the clearance of severe acute respiratory syndrome coronavirus (SARS-CoV-2). Obese diseased adipose tissues overexpress the receptors and proteases for the SARS-CoV-2 entry, implicating its possible roles as virus reservoir and accelerator reinforcing violent systemic inflammation and immune response. Finally, anti-inflammatory cytokines like anti-interleukin 6 and administration of mesenchymal stromal/stem cells may serve as potential immune modulatory therapies for supportively combating COVID-19. Obesity is conversely related to the development of COVID-19 through numerous molecular mechanisms and individuals with obesity belong to the COVID-19-susceptible population requiring more protective measures.

Exosomics

Extracellular vesicles have been the focus of a large number of studies in the past five years. Exosomes, a subgroup of extracellular vesicles, are of particularly high interest because they partake in a wide number of biological pathways. Produced by a variety of cells, exosomes have an important role in both physiological and pathological conditions. Exosome cargo heavily defines the vesicles’ unique characteristics, and the cargo with the most intriguing prospects in its’ biomedical applications is the non-coding RNAs. Non-coding RNAs, and specifically microRNAs are implicated in the regulation of many biological processes and have been associated with numerous diseases. Exosomes containing such important cargo can be used as biomarkers, therapeutic biomaterials, or even drug carriers. The potential media use of exosomes seems promising. However, some obstacles should be overcome before their clinical application. Synthetic exosome-like biomolecules may be a solution, but their production is still in their beginning stages. This review provides concise information regarding the current trends in exosome studies.

Electro-Acupuncture Promotes the Differentiation of Endogenous Neural Stem Cells via Exosomal microRNA 146b After Ischemic Stroke

Background: Evidences indicate that exosomes-mediated delivery of microRNAs (miRNAs or miRs) is involved in the neurogenesis of stroke. This study was to investigate the role of exosomal miRNAs in non-drug therapy of electro-acupuncture (EA) regulating endogenous neural stem cells for stroke recovery.

Methods: The model of focal cerebral ischemia and reperfusion in rats were established by middle cerebral artery occlusion (MCAO) and treated by EA. The exosomes were extracted from peri-ischemic striatum and identified by exosomal biomarkers, and detected differentially expressed miRNAs with microarray chip. Primary stem cells were cultured, and oxygen–glucose deprivation and reperfusion (OGD/R) was used to mimic vitro ischemic injury.

Results: The levels of exosomal biomarkers TSG101 and CD81 were increased in peri-ischemic striatum after EA treatment, and we revealed 25 differentially expressed miRNAs in isolated exosomes, of which miR-146b was selected for further analysis, and demonstrated that EA increased miR-146b expression and its inhibitors could block the effects. Subsequently, we confirmed that EA upregulated miR-146b expression to promote neural stem cells differentiation into neurons in peri-ischemic striatum. In vitro, it was verified that OGD/R hindered neural stem cells differentiation, and miR-146b inhibitors furtherly suppressed its differentiation, simultaneously NeuroD1 was involved in neural stem cells differentiation into neurons. Moreover, in vivo we found EA promoted NeuroD1-mediated neural stem cells differentiation via miR-146b. In addition, EA also could improve neurological deficits through miR-146b after ischemic stroke.

Conclusion: EA promotes the differentiation of endogenous neural stem cells via exosomal miR-146b to improve neurological injury after ischemic stroke.

Extracellular vesicles derived from human placental mesenchymal stem cells alleviate experimental colitis in mice by inhibiting inflammation and oxidative stress

Mesenchymal stem cells (MSCs) are pluripotent cells that can be applied to the treatment of immune disorders, including inflammatory bowel disease (IBD). The therapeutic effects of MSCs have been mostly attributed to the secretion of soluble factors with paracrine actions, such as extracellular vesicles (EVs), which may play a relevant role in the repair of damaged tissues. In the present study, a mouse model of colitis was induced with the use of trinitrobenzene sulfonic acid (TNBS). EVs derived from human placental mesenchymal stem cells (hP‑MSCs) were used for the treatment of colitis by in situ injection. Clinical scores were applied to verify the therapeutic effects of EVs on mice with colitis. Inflammation in the colon was evaluated by measuring the levels of various inflammatory cytokines. The content of reactive oxygen species (ROS) was detected by the use of molecular imaging methods for real‑time tracking and the therapeutic effects of EVs on mucosal healing in mice with colitis were evaluated. The results revealed that the injection of EVs regulated the balance of pro‑inflammatory and anti‑inflammatory cytokines in colon tissue. Treatment with EVs also suppressed oxidative stress by decreasing the activity of myeloperoxidase (MPO) and ROS. Histological analysis further confirmed that the EVs significantly promoted mucosal healing, as reflected by the promotion of the proliferation of colonic epithelial cells and the maintenance of tight junctions. Taken together, the findings of the present study demonstrated that EVs derived from hP‑MSCs alleviated TNBS‑induced colitis by inhibiting inflammation and oxidative stress. These findings may provide a novel theoretical basis for the EV‑based treatment of IBD.

Extracellular vesicle-enclosed miR-486-5p mediates wound healing with adipose-derived stem cells by promoting angiogenesis

Adipose‐derived stem cells (ASC) are said to have a pivotal role in wound healing. Specifically, ASC‐secreted extracellular vesicles (EV) carry diverse cargos such as microRNAs (miRNAs) to participate in the ASC‐based therapies. Considering its effects, we aimed to investigate the role of ASC‐EVs in the cutaneous wound healing accompanied with the study on the specific cargo‐medicated effects on wound healing. Two full‐thickness excisional skin wounds were created on mouse dorsum, and wound healing was recorded at the indicated time points followed by histological analysis and immunofluorescence staining for CD31 and α‐SMA. Human skin fibroblasts (HSFs) and human microvascular endothelial cells (HMECs) were co‐cultured with EVs isolated from ASC (ASC‐EVs), respectively, followed by the evaluation of their viability and mobility using CCK‐8, scratch test and transwell migration assays. Matrigel‐based angiogenesis assays were performed to evaluate vessel‐like tube formation by HMECs in vitro. ASC‐EVs accelerated the healing of full‐thickness skin wounds, increased re‐epithelialization and reduced scar thickness whilst enhanced collagen synthesis and angiogenesis in murine models. However, miR‐486‐5p antagomir abrogated the ASC‐EVs‐induced effects. Intriguingly, miR‐486‐5p was found to be highly enriched in ASC‐EVs, exhibiting an increase in viability and mobility of HSFs and HMECs and enhanced the angiogenic activities of HMECs. Notably, we also demonstrated that ASC‐EVs‐secreted miR‐486‐5p achieved the aforesaid effects through its target gene Sp5. Hence, our results suggest that miR‐486‐5p released by ASC‐EVs could be a critical mediator to develop an ASC‐based therapeutic strategy for wound healing.

Differential Wound Healing Capacity of Mesenchymal Stem Cell-Derived Exosomes Originated From Bone Marrow, Adipose Tissue and Umbilical Cord Under Serum- and Xeno-Free Condition

Exosomes are nano-scale and closed membrane vesicles which are promising for therapeutic applications due to exosome-enclosed therapeutic molecules such as DNA, small RNAs, proteins and lipids. Recently, it has been demonstrated that mesenchymal stem cell (MSC)-derived exosomes have capacity to regulate many biological events associated with wound healing process, such as cell proliferation, cell migration and blood vessel formation. This study investigated the regenerative potentials for cutaneous tissue, in regard to growth factors associated with wound healing and skin cell proliferation and migration, by exosomes released from primary MSCs originated from bone marrow (BM), adipose tissue (AD), and umbilical cord (UC) under serum- and xeno-free condition. We found crucial wound healing-mediated growth factors, such as vascular endothelial growth factor A (VEGF-A), fibroblast growth factor 2 (FGF-2), hepatocyte growth factor (HGF), and platelet-derived growth factor BB (PDGF-BB) in exosomes derived from all three MSC sources. However, expression levels of these growth factors in exosomes were influenced by MSC origins, especially transforming growth factor beta (TGF-β) was only detected in UCMSC-derived exosomes. All exosomes released by three MSCs sources induced keratinocyte and fibroblast proliferation and migration; and, the induction of cell migration is a dependent manner with the higher dose of exosomes was used (20 μg), the faster migration rate was observed. Additionally, the influences of exosomes on cell proliferation and migration was associated with exosome origins and also target cells of exosomes that the greatest induction of primary dermal fibroblasts belongs to BMMSC-derived exosomes and keratinocytes belongs to UCMSC-derived exosomes. Data from this study indicated that BMMSCs and UCMSCs under clinical condition secreted exosomes are promising to develop into therapeutic products for wound healing treatment.

Microvesicles from Human Immortalized Cell Lines of Endothelial Progenitor Cells and Mesenchymal Stem/Stromal Cells of Adipose Tissue Origin as Carriers of Bioactive Factors Facilitating Angiogenesis

Endothelial progenitor cells (EPCs) and mesenchymal stem/stromal cells (MSCs) are associated with maintaining tissue homeostasis and tissue repair. Both types of cells contribute to tissue regeneration through the secretion of trophic factors (alone or in the form of microvesicles). This study investigated the isolation and biological properties of microvesicles (MVs) derived from human immortalized MSC line HATMSC1 of adipose tissue origin and EPC line. The human immortalized cell line derived from the adipose tissue of a patient with venous stasis was established in our laboratory using the hTERT and pSV402 plasmids. The human EPC line originating from cord blood (HEPC-CB.1) was established in our previous studies. Microvesicles were isolated through a sequence of centrifugations. Analysis of the protein content of both populations of microvesicles, using the Membrane-Based Antibody Array and Milliplex ELISA showed that isolated microvesicles transported growth factors and pro- and antiangiogenic factors. Analysis of the miRNA content of isolated microvesicles revealed the presence of proangiogenic miRNA (miR-126, miR-296, miR-378, and miR-210) and low expression of antiangiogenic miRNA (miR-221, miR-222, and miR-92a) using real-time RT-PCR with the TaqMan technique. The isolated microvesicles were assessed for their effect on the proliferation and proangiogenic properties of cells involved in tissue repair. It was shown that both HEPC-CB.1- and HATMSC1-derived microvesicles increased the proliferation of human endothelial cells of dermal origin and that this effect was dose-dependent. In contrast, microvesicles had a limited impact on the proliferation of fibroblasts and keratinocytes. Both types of microvesicles improved the proangiogenic properties of human dermal endothelial cells, and this effect was also dose-dependent, as shown in the Matrigel assay. These results confirm the hypothesis that microvesicles of HEPC-CB.1 and HATMSC1 origin carry proteins and miRNAs that support and facilitate angiogenic processes that are important for cutaneous tissue regeneration.

Advances in regenerative therapy: A review of the literature and future directions

There is enormous global anticipation for stem cell-based therapies that are safe and effective. Numerous pre-clinical studies present encouraging results on the therapeutic potential of different cell types including tissue derived stem cells. Emerging evidences in different fields of research suggest several cell types are safe, whereas their therapeutic application and effectiveness remain challenged. Multiple factors that influence treatment outcomes are proposed including immunocompatibility and potency, owing to variations in tissue origin, ex-vivo methodologies for preparation and handling of the cells. This communication gives an overview of literature data on the different types of cells that are potentially promising for regenerative therapy. As a case in point, the recent trends in research and development of the mesenchymal stem cells (MSCs) for cell therapy are considered in detail. MSCs can be isolated from a variety of tissues and organs in the human body including bone marrow, adipose, synovium, and perinatal tissues. However, MSC products from the different tissue sources exhibit unique or varied levels of regenerative abilities. The review finally focuses on adipose tissue-derived MSCs (ASCs), with the unique properties such as easier accessibility and abundance, excellent proliferation and differentiation capacities, low immunogenicity, immunomodulatory and many other trophic properties. The suitability and application of the ASCs, and strategies to improve the innate regenerative capacities of stem cells in general are highlighted among others.

Extracellular vesicles derived from different sources of mesenchymal stem cells: therapeutic effects and translational potential

Mesenchymal stem cells (MSCs) were known to have excellent properties in cell therapy. However, the risk of immune rejection associated with cell transplant therapy hampers its use. Extracellular vesicles secreted by MSCs derived from different sources that contain therapeutic molecules such as RNA and proteins, which is a novel strategy for cell-free therapy. Recently, researches show EVs from MSCs (MSC-EVs) of different sources have special functions and effects on different diseases. Here, we collected these researches and compared them to each other. In addition, their potential and possible application in clinical treatment are described.

Early diagnosis of breast and ovarian cancers by body fluids circulating tumor-derived exosomes

Exosomes (EXs) are small extracellular vesicles, a size range of 40-100 nm in diameter, actively secreted by most eukaryotic cells into surrounding body fluids like blood, saliva, urine, bile, breast milk and etc. These endosomal-derived vesicles mediate cell-cell communication between various cell populations through transmitting different signaling molecules such as lipids, proteins, and nucleic acids, and participate in a wide range of physiological and pathological body processes. Tumor-derived EXs (TDEs) are vehicles for intercellular communications by transferring bioactive molecules; they deliver oncogenic molecules and contain different molecular cargoes compared to EXs delivered from normal cells, therefore, they can be used as non-invasive invaluable biomarkers for early diagnosis and prognosis of most cancers, including breast and ovarian cancers. Their presence and stability in different types of body fluids highlight them as a suitable diagnostic biomarker for distinguishing various cancer stages. In addition, EXs can predict the therapeutic efficacy of chemotherapy agents and drug resistance in cancer cells, as well as determine the risk of metastasis in different disease stages. In this study, the recent literature on the potential role of TDEs in the diagnosis and prognosis of ovarian and breast cancers is summarized, and then exosome isolation techniques including traditional and new approaches are briefly discussed.

The opposite functions of miR-24 in the osteogenesis and adipogenesis of adipose-derived mesenchymal stem cells are mediated by the HOXB7/β-catenin complex

Adipose-derived mesenchymal stem cells (ADMSCs) used in combination with nanoparticles or scaffolds represent promising candidates for bone engineering. Compared to bone marrow-derived MSCs (BMMSCs), ADMSCs show a relatively low capacity for osteogenesis. In the current study, miR-24 was identified as an osteogenesis- and adipogenesis-related miRNA that performs opposing roles (inhibition in osteogenesis and promotion in adipogenesis) during these two differentiation processes. Through bioinformatics analysis and luciferase reporter assays, homeobox protein Hox-B7 (HOXB7) was identified as a potential novel downstream target of miR-24 that contains a miR-24 binding site in the 3'-UTR of its mRNA. Overexpression of HOXB7 could partly halt the inhibitory effect of miR-24 on osteogenesis, and downregulation of HOXB7 could also partly suppress the positive effect of miR-24 on adipogenesis. Furthermore, immunoprecipitation experiments found that HOXB7 and β-catenin formed a functional complex that acted as an essential modulator during osteogenesis and adipogenesis of ADMSCs. After transfecting ADMSCs with an MSNs-PEI-miR-24 agomir or antagomir and loading the cells onto gelatin-chitosan scaffolds, the compounds were assessed for their abilities to repair the critical-sized calvarial defects in rats. Comprehensive evaluation, including micro-CT, sequential fluorescent labeling, and immunohistochemistry analysis, revealed that silencing miR-24 distinctly promoted in vivo bone remolding, whereas overexpression of miR-24 significantly repressed bone formation. Taken together, our findings demonstrated opposite roles for the miR-24/HOXB7/β-catenin signaling pathway in the osteogenesis and adipogenesis of ADMSCs, which may provide a novel mechanism for determining the balance between these two biological processes.

The proangiogenic effects of extracellular vesicles secreted by dental pulp stem cells derived from periodontally compromised teeth

Background

Although dental pulp stem cells (DPSCs) isolated from periodontally compromised teeth (P-DPSCs) have been demonstrated to retain pluripotency and regenerative potential, their use as therapeutics remains largely unexplored. In this study, we investigated the proangiogenic effects of extracellular vesicles (EVs) secreted by P-DPSCs using in vitro and in vivo testing models.

Methods

Patient-matched DPSCs derived from periodontally healthy teeth (H-DPSCs) were used as the control for P-DPSCs. Conditioned media (CMs) derived from H-DPSCs and P-DPSCs (H-CM and P-CM), CMs derived from both cell types pretreated with the EV secretion blocker GW4869 (H-GW and P-GW), and EVs secreted by H-DPSCs and P-DPSCs (H-EVs and P-EVs) were prepared to test their proangiogenic effects on endothelial cells (ECs). Cell proliferation, migration, and tube formation were assessed using the Cell Counting Kit-8 (CCK-8), transwell/scratch wound healing, and Matrigel assays, respectively. Specifically, quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and western blot analysis were used to examine the expression levels of angiogenesis-related genes/proteins in ECs in response to EV-based incubation. Finally, a full-thickness skin defect model was applied to test the effects of EVs on wound healing and new vessel formation.

Results

Both H-CM and P-CM promoted EC angiogenesis, but the proangiogenic effects were compromised when ECs were incubated in H-GW and P-GW, wherein the EV secretion was blocked by pretreatment with GW4869. In EV-based incubations, although both H-EVs and P-EVs were found to enhance the angiogenesis-related activities of ECs, P-EVs exerted a more robust potential to stimulate EC proliferation, migration, and tube formation. In addition, P-EVs led to higher expression levels of angiogenesis-related genes/proteins in ECs than H-EVs. Similarly, both P-EVs and H-EVs were found to accelerate wound healing and promote vascularization across skin defects in mice, but wounds treated with P-EVs resulted in a quicker healing outcome and enhanced new vessel formation.

Conclusions

The findings of the present study provide additional evidence that P-DPSCs derived from periodontally diseased teeth represent a potential source of cells for research and therapeutic use. Particularly, the proangiogenic effects of P-EVs suggest that P-DPSCs may be used to promote new vessel formation in cellular therapy and regenerative medicine.

Engineering of Exosomes to Target Cancer Metastasis

As a nanoscale subset of extracellular vehicles, exosomes represent a new pathway of intercellular communication by delivering cargos such as proteins and nucleic acids to recipient cells. Importantly, it has been well documented that exosome-mediated delivery of such cargo is involved in many pathological processes such as tumor progression, cancer metastasis, and development of drug resistance. Innately biocompatible and possessing ideal structural properties, exosomes offer distinct advantages for drug delivery over artificial nanoscale drug carriers. In this review, we summarize recent progress in methods for engineering exosomes including isolation techniques and exogenous cargo encapsulation, with a focus on applications of engineered exosomes to target cancer metastasis.

Utilization of Human Induced Pluripotent Stem Cells for Cardiac Repair

The paracrine effect, mediated by chemical signals that induce a physiological response on neighboring cells in the same tissue, is an important regenerative mechanism for stem cell-based therapy. Exosomes are cell-secreted nanovesicles (50–120 nm) of endosomal origin, and have been demonstrated to be a major contributor to the observed stem cell-mediated paracrine effect in the cardiac repair process. Following cardiac injury, exosomes deriving from exogenous stem cells have been shown to regulate cell apoptosis, proliferation, angiogenesis, and fibrosis in the infarcted heart. Exosomes also play a crucial role in the intercellular communication between donor and recipient cells. Human induced pluripotent stem cells (hiPSCs) are promising cell sources for autologous cell therapy in regenerative medicine. Here, we review recent advances in the field of progenitor-cell derived, exosome-based cardiac repair, with special emphasis on exosomes derived from hiPSCs.

Clinical potential and current progress of mesenchymal stem cells for Parkinson's disease: a systematic review

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease characterized by severe dyskinesia due to a progressive loss of dopaminergic neurons along the nigro-striatal pathway. The current focus of treatment is to relieve symptoms through administration of levodopa, such as L-3,4-dihydroxy phenylalanine replacement therapy, dopaminergic agonist administration, functional neurosurgery, and gene therapy, rather than preventing dopaminergic neuronal damage. Hence, the application and development of neuroprotective/disease modification strategies is absolutely necessary. Currently, stem cell therapy has been considered for PD treatment. As for the stem cells, mesenchymal stem cells (MSCs) seem to be the most promising. In this review, we analyze the mechanisms of action of MSCs in Parkinson's disease, including growth factor secretion, exocytosis, and attenuation of neuroinflammation. To determine efficacy and protect patients from possible adverse effects, ongoing rigorous and controlled studies of MSC treatment will be critical.

Transplantation Site Affects the Outcomes of Adipose-Derived Stem Cell-Based Therapy for Retinal Degeneration

Adipose-derived stem cells (ASCs) have shown a strong protective effect on retinal degenerative diseases (RDD) after being transplanted into the subretinal space in an animal model. Recently, several clinical trials have been conducted to treat RDD with intravitreal transplantation of stem cells, including ASCs. However, the outcomes of the clinical trials were not satisfactory. To investigate if the transplantation site alters the outcome of stem cell-based therapy for RDD, we isolated rat ASCs (rASCs) and labeled them with green fluorescent protein. Autologous rASCs were grafted into the vitreous chamber or subretinal space in a rat RDD model induced by sodium iodate (SI). The electric response was recorded by ERG. The anatomic structure of the retina was observed in cryosections of rat eyes at posttransplantation weeks 1, 2, and 4. Neural retina apoptosis and epiretinal membrane- (ERM-) like structure formation were investigated by immunostaining. The intravitreal transplantation of rASCs resulted in an extinguished electric response, although the rosette formation and apoptosis of neural retina were reduced. However, the rASCs that grafted in the subretinal space protected the retina from the damage caused by SI, including a partial recovering of the electric response and a reduction in rosette formation. Intravitreally grafted rASCs formed a membrane, resulting in retina folding at the injection site. Müller cells, retinal pigment epithelial cells, and microglial cells migrated from the retina to the rASC-formed membrane and subsequently formed an ERM-like structure. Furthermore, vitreous fluid promoted rASC migration, and rASC-conditioned medium enhanced Müller cell migration as indicated by in vitro studies. These data suggested that the vitreous chamber is not a good transplantation site for ASC-based therapy for RDD and that a deliberate decision should be made before transplantation of stem cells into the vitreous chamber to treat RDD in clinical trials.

The Cellular and Molecular Patterns Involved in the Neural Differentiation of Adipose-Derived Stem Cells

Injuries to the nervous system cause serious problems among affected patients by preventing them from the possibility of living a normal life. As this tissue possesses a reduced capacity of self-regeneration currently, lots of different strategies are being developed in order to make the regeneration in the nervous system possible. Among them, tissue engineering and stem cell-based therapies are to date very exploded fields and tremendous progress has been made in this direction. As the two main components of the nervous system, react differently to injuries and behave different during disease, it is clear that two separate regeneration approaches have been taken into consideration during development of treatment. Special attention is constantly given to the potential of adipose-derived stem cells for this kind of application. Due to the fact that they present remarkable properties, they can easily be obtained and have demonstrated that are capable of engaging in neural and glial lineages, adipose-derived stem cells are promising tools for the field of nervous system regeneration. Moreover, new insights into epigenetic control and modifications during the differentiation of adipose-derived stem cells towards the neural liege could provide new methods to maximize the regeneration process. In this review, we summarize the current applications of adipose-derived stem cells for neural regeneration and discuss in-depth molecular patterns involved in the differentiation of adipose-derived stem cells in neuron-like cells and Schwann-like cells.