Adipose stem cell-derived nanovesicles inhibit emphysema primarily via an FGF2-dependent pathway

Extracellular vesicles in cancer cachexia: deciphering pathogenic roles and exploring therapeutic horizons

Cancer cachexia (CC) is a debilitating syndrome that affects 50-80% of cancer patients, varying in incidence by cancer type and significantly diminishing their quality of life. This multifactorial syndrome is characterized by muscle and fat loss, systemic inflammation, and metabolic imbalance. Extracellular vesicles (EVs), including exosomes and microvesicles, play a crucial role in the progression of CC. These vesicles, produced by cancer cells and others within the tumor environment, facilitate intercellular communication by transferring proteins, lipids, and nucleic acids. A comprehensive review of the literature from databases such as PubMed, Scopus, and Web of Science reveals insights into the formation, release, and uptake of EVs in CC, underscoring their potential as diagnostic and prognostic biomarkers. The review also explores therapeutic strategies targeting EVs, which include modifying their release and content, utilizing them for drug delivery, genetically altering their contents, and inhibiting key cachexia pathways. Understanding the role of EVs in CC opens new avenues for diagnostic and therapeutic approaches, potentially mitigating the syndrome's impact on patient survival and quality of life.

A new frontier in precision medicine: Exploring the role of extracellular vesicles in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory airway disease characterized by progressive respiratory difficulties. It has a high incidence and disability rate worldwide. However, currently there is still a lack of highly effective treatment methods for COPD, only symptom relief is possible. Therefore, there is an urgent need to explore new treatment options. Almost all cells can secrete extracellular vesicles (EVs), which participate in many physiological activities by transporting cargoes and are associated with the pathogenesis of various diseases. Recently, many scholars have extensively studied the relationship between COPD and EVs, which has strongly demonstrated the significant impact of EVs from different sources on the occurrence and development of COPD. Therefore, EVs are a good starting point and new opportunity for the diagnosis and treatment of COPD. In this review, we mainly describe the current mechanisms of EVs in the pathogenesis of COPD, also the relationship between diagnosis, prognosis, and treatment. At the same time, we also introduce some new methods for COPD therapy based on EVs. It is hoped that this article can provide new ideas for future research and contribute to the development of precision medicine.

MicroRNA-155 mediates multiple gene regulations pertinent to the role of human adipose-derived mesenchymal stem cells in skin regeneration

Introduction: The role of Adipose-derived mesenchymal stem cells (AD-MSCs) in skin wound healing remains to be fully characterized. This study aims to evaluate the regenerative potential of autologous AD-MSCs in a non-healing porcine wound model, in addition to elucidate key miRNA-mediated epigenetic regulations that underlie the regenerative potential of AD-MSCs in wounds. Methods: The regenerative potential of autologous AD-MSCs was evaluated in porcine model using histopathology and spatial frequency domain imaging. Then, the correlations between miRNAs and proteins of AD-MSCs were evaluated using an integration analysis in primary human AD-MSCs in comparison to primary human keratinocytes. Transfection study of AD-MSCs was conducted to validate the bioinformatics data. Results: Autologous porcine AD-MSCs improved wound epithelialization and skin properties in comparison to control wounds. We identified 26 proteins upregulated in human AD-MSCs, including growth and angiogenic factors, chemokines and inflammatory cytokines. Pathway enrichment analysis highlighted cell signalling-associated pathways and immunomodulatory pathways. miRNA-target modelling revealed regulations related to genes encoding for 16 upregulated proteins. miR-155-5p was predicted to regulate Fibroblast growth factor 2 and 7, C-C motif chemokine ligand 2 and Vascular cell adhesion molecule 1. Transfecting human AD-MSCs cell line with anti-miR-155 showed transient gene silencing of the four proteins at 24 h post-transfection. Discussion: This study proposes a positive miR-155-mediated gene regulation of key factors involved in wound healing. The study represents a promising approach for miRNA-based and cell-free regenerative treatment for difficult-to-heal wounds. The therapeutic potential of miR-155 and its identified targets should be further explored in-vivo.

Physical modulation of mesenchymal stem cell exosomes: A new perspective for regenerative medicine

Mesenchymal stem cell-derived exosomes (MSC-Exo) offer promising therapeutic potential for various refractory diseases, presenting a novel therapeutic strategy. However, their clinical application encounters several obstacles, including low natural secretion, uncontrolled biological functions and inherent heterogeneity. On the one hand, physical stimuli can mimic the microenvironment dynamics where MSC-Exo reside. These factors influence not only their secretion but also, significantly, their biological efficacy. Moreover, physical factors can also serve as techniques for engineering exosomes. Therefore, the realm of physical factors assumes a crucial role in modifying MSC-Exo, ultimately facilitating their clinical translation. This review focuses on the research progress in applying physical factors to MSC-Exo, encompassing ultrasound, electrical stimulation, light irradiation, intrinsic physical properties, ionizing radiation, magnetic field, mechanical forces and temperature. We also discuss the current status and potential of physical stimuli-affected MSC-Exo in clinical applications. Furthermore, we address the limitations of recent studies in this field. Based on this, this review provides novel insights to advance the refinement of MSC-Exo as a therapeutic approach in regenerative medicine.

Injectable Multifunctional Composite Hydrogel as a Combination Therapy for Preventing Postsurgical Adhesion

Postsurgical adhesion (PA) is a common and serious postoperative complication that affects millions of patients worldwide. However, current commercial barrier materials are insufficient to inhibit diverse pathological factors during PA formation, and thus, highly bioactive materials are needed. Here, this work designs an injectable multifunctional composite hydrogel that can serve as a combination therapy for preventing PA. In brief, this work reveals that multiple pathological events, such as chronic inflammatory and fibrotic processes, contribute to adhesion formation in vivo, and such processes can not be attenuated by barrier material (e.g., hydrogel) alone treatments. To solve this limitation, this work designs a composite hydrogel made of the cationic self-assembling peptide KLD2R and TGF-β receptor inhibitor (TGF-βRi)-loaded mesenchymal stem cell-derived nanovesicles (MSC-NVs). The resulting composite hydrogel displays multiple functions, including physical separation of the injured tissue areas, antibacterial effects, and local delivery and sustained release of anti-inflammatory MSC-NVs and antifibrotic TGF-βRi. As a result, this composite hydrogel effectively inhibited local inflammation, fibrosis and adhesion formation in vivo. Moreover, the hydrogel also exhibits good biocompatibility and biodegradability in vivo. Together, the results highlight that this "all-in-one" composite hydrogel strategy may provide insights into designing advanced therapies for many types of tissue injury.

Engineering Cell-Derived Nanovesicles for Targeted Immunomodulation

Extracellular vesicles (EVs) show promise for targeted drug delivery but face production challenges with low yields. Cell-derived nanovesicles (CDNVs) made by reconstituting cell membranes could serve as EV substitutes. In this study, CDNVs were generated from mesenchymal stem cells by extrusion. Their proteomic composition, in vitro and in vivo toxicity, and capacity for loading RNA or proteins were assessed. Compared with EVs, CDNVs were produced at higher yields, were comprised of a broader range of proteins, and showed no detrimental effects on cell proliferation, DNA damage, or nitric oxide production in vitro or on developmental toxicity in vivo. CDNVs could be efficiently loaded with RNA and engineered to modify surface proteins. The feasibility of generating immunomodulatory CDNVs was demonstrated by preparing CDNVs with enhanced surface expression of PD1, which could bind to PD-L1 expressing tumor cells, enhance NK and T cell degranulation, and increase immune-mediated tumor cell death. These findings demonstrate the adaptability and therapeutic promise of CDNVs as promising substitutes for natural EVs that can be engineered to enhance immunomodulation.

Exosomes as cutting-edge therapeutics in various biomedical applications: An update on engineering, delivery, and preclinical studies

Exosomes are cell-derived nanovesicles, circulating in different body fluids, and acting as an intercellular mechanism. They can be purified from culture media of different cell types and carry an enriched content of various protein and nucleic acid molecules originating from their parental cells. It was indicated that the exosomal cargo can mediate immune responses via many signaling pathways. Over recent years, the therapeutic effects of various exosome types were broadly investigated in many preclinical studies. Herein, we present an update on recent preclinical studies on exosomes as therapeutic and/or delivery agents for various applications. The exosome origin, structural modifications, natural or loaded active ingredients, size, and research outcomes were summarized for various diseases. Overall, the present article provides an overview of the latest exosome research interests and developments to clear the way for the clinical study design and application.

Biogenesis, Composition and Potential Therapeutic Applications of Mesenchymal Stem Cells Derived Exosomes in Various Diseases

Exosomes are nanovesicles with a wide range of chemical compositions used in many different applications. Mesenchymal stem cell-derived exosomes (MSCs-EXOs) are spherical vesicles that have been shown to mediate tissue regeneration in a variety of diseases, including neurological, autoimmune and inflammatory, cancer, ischemic heart disease, lung injury, and liver fibrosis. They can modulate the immune response by interacting with immune effector cells due to the presence of anti-inflammatory compounds and are involved in intercellular communication through various types of cargo. MSCs-EXOs exhibit cytokine storm-mitigating properties in response to COVID-19. This review discussed the potential function of MSCs-EXOs in a variety of diseases including neurological, notably epileptic encephalopathy and Parkinson's disease, cancer, angiogenesis, autoimmune and inflammatory diseases. We provided an overview of exosome biogenesis and factors that regulate exosome biogenesis. Additionally, we highlight the functions and potential use of MSCs-EXOs in the treatment of the inflammatory disease COVID-19. Finally, we covered a strategies and challenges of MSCs-EXOs. Finally, we discuss conclusion and future perspectives of MSCs-EXOs.

Wnt3a-Loaded Extracellular Vesicles Promote Alveolar Epithelial Regeneration after Lung Injury

Compromised regeneration resulting from the deactivation of Wnt/β-catenin signaling contributes to the progression of chronic obstructive pulmonary disease (COPD) with limited therapeutic options. Extracellular cytokine-induced Wnt-based signaling provides an alternative option for COPD treatment. However, the hydrophobic nature of Wnt proteins limits their purification and use. This study devises a strategy to deliver the membrane-bound wingless-type MMTV integration site family, member 3A (Wnt3a) over a long distance by anchoring it to the surface of extracellular vesicles (EVs). The newly engineered Wnt3aWG EVs are generated by co-expressing Wnt3a with two genes encoding the membrane protein, WLS, and an engineered glypican, GPC6ΔGPI -C1C2. The bioactivity of Wnt3aWG EVs is validated using a TOPFlash assay and a mesoderm differentiation model of human pluripotent stem cells. Wnt3aWG EVs activate Wnt signaling and promote cell growth following human alveolar epithelial cell injury. In an elastase-induced emphysema model, impaired pulmonary function and enlarged airspace are greatly restored by the intravenous delivery of Wnt3aWG EVs. Single-cell RNA sequencing-based analyses further highlight that Wnt3aWG EV-activated regenerative programs are responsible for its beneficial effects. These findings suggest that EV-based Wnt3a delivery represents a novel therapeutic strategy for lung repair and regeneration after injury.

Potential angiogenic, immunomodulatory, and antifibrotic effects of mesenchymal stem cell-derived extracellular vesicles in systemic sclerosis

Systemic sclerosis (SSc) is an intricate systemic autoimmune disease with pathological features such as vascular injury, immune dysregulation, and extensive fibrosis of the skin and multiple organs. Treatment options are limited; however, recently, mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have been acknowledged in preclinical and clinical trials as being useful in treating autoimmune diseases and are likely superior to MSCs alone. Recent research has also shown that MSC-EVs can ameliorate SSc and the pathological changes in vasculopathy, immune dysfunction, and fibrosis. This review summarizes the therapeutic effects of MSC-EVs on SSc and the mechanisms that have been discovered to provide a theoretical basis for future studies on the role of MSC-EVs in treating SSc.

Extracellular vesicles and COPD: foe or friend?

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory airway disease characterized by progressive airflow limitation. The complex biological processes of COPD include protein hydrolysis tissue remodeling, innate immune inflammation, disturbed host-pathogen response, abnormal cellular phenotype conversion, and cellular senescence. Extracellular vesicles (EVs) (including apoptotic vesicles, microvesicles and exosomes), are released by almost all cell types and can be found in a variety of body fluids including blood, sputum and urine. EVs are key mediators in cell-cell communication and can be used by using their bioactive substances (DNA, RNA, miRNA, proteins and other metabolites) to enable cells in adjacent and distant tissues to perform a wide variety of functions, which in turn affect the physiological and pathological functions of the body. Thus, EVs is expected to play an important role in the pathogenesis of COPD, which in turn affects its acute exacerbations and may serve as a diagnostic marker for it. Furthermore, recent therapeutic approaches and advances have introduced EVs into the treatment of COPD, such as the modification of EVs into novel drug delivery vehicles. Here, we discuss the role of EVs from cells of different origins in the pathogenesis of COPD and explore their possible use as biomarkers in diagnosis, and finally describe their role in therapy and future prospects for their application. Graphical Abstract.

Bioengineered exosomal-membrane-camouflaged abiotic nanocarriers: neurodegenerative diseases, tissue engineering and regenerative medicine

A bio-inspired strategy has recently been developed for camouflaging nanocarriers with biomembranes, such as natural cell membranes or subcellular structure-derived membranes. This strategy endows cloaked nanomaterials with improved interfacial properties, superior cell targeting, immune evasion potential, and prolonged duration of systemic circulation. Here, we summarize recent advances in the production and application of exosomal membrane-coated nanomaterials. The structure, properties, and manner in which exosomes communicate with cells are first reviewed. This is followed by a discussion of the types of exosomes and their fabrication methods. We then discuss the applications of biomimetic exosomes and membrane-cloaked nanocarriers in tissue engineering, regenerative medicine, imaging, and the treatment of neurodegenerative diseases. Finally, we appraise the current challenges associated with the clinical translation of biomimetic exosomal membrane-surface-engineered nanovehicles and evaluate the future of this technology.

Mesenchymal Stem Cell-Derived Extracellular Vesicles: New Soldiers in the War on Immune-Mediated Diseases

Inflammatory diseases are a group of debilitating disorders with varying degrees of long-lasting functional impairment of targeted system. New therapeutic agents that will attenuate on-going inflammation and, at the same time, promote regeneration of injured organ are urgently needed for the treatment of autoimmune and inflammatory disorders. During the last decade numerous studies have demonstrated that crucial therapeutic benefits of mesenchymal stem cells (MSCs) in inflammatory diseases are based on the effects of MSC-produced paracrine mediators and not on the activity of engrafted cells themselves. Thus, to overcome the limitations of stem cell transplantation, MSC-derived extracellular vesicles (MSC-EVs) have been rigorously investigated, as a promising cell-free pharmaceutical component. In this review, we focus on the mechanisms of MSC-EV covering the current knowledge on their potential therapeutic applications for immune-mediated diseases.

Mesenchymal Stromal Cells and their EVs as Potential Leads for SARSCoV2 Treatment

In December 2019, a betacoronavirus was isolated from pneumonia cases in China and rapidly turned into a pandemic of COVID-19. The virus is an enveloped positive-sense ssRNA and causes a severe respiratory syndrome along with a cytokine storm, which is the main cause of most complications. Therefore, treatments that can effectively control the inflammatory reactions are necessary. Mesenchymal Stromal Cells and their EVs are well-known for their immunomodulatory effects, inflammation reduction, and regenerative potentials. These effects are exerted through paracrine secretion of various factors. Their EVs also transport various molecules such as microRNAs to other cells and affect recipient cells' behavior. Scores of research and clinical trials have indicated the therapeutic potential of EVs in various diseases. EVs also seem to be a promising approach for severe COVID-19 treatment. EVs have also been used to develop vaccines since EVs are biocompatible nanoparticles that can be easily isolated and engineered. In this review, we have focused on the use of Mesenchymal Stromal Cells and their EVs for the treatment of COVID-19, their therapeutic capabilities, and vaccine development.

GMP-compliant manufacturing of biologically active cell-derived vesicles produced by extrusion technology

Extracellular vesicles (EVs) released by a variety of cell types have been shown to act as a natural delivery system for bioactive molecules such as RNAs and proteins. EV therapy holds great promise as a safe and cell-free therapy for many immunological and degenerative diseases. However, translation to clinical application is limited by several factors, including insufficient large-scale manufacturing technologies and low yield. We have developed a novel drug delivery platform technology, BioDrone™, based on cell-derived vesicles (CDVs) produced from diverse cell sources by using a proprietary extrusion process. This extrusion technology generates nanosized vesicles in far greater numbers than naturally obtained EVs. We demonstrate that the CDVs are surrounded by a lipid bilayer membrane with a correct membrane topology. Physical, biochemical and functional characterisation results demonstrate the potential of CDVs to act as effective therapeutics. Umbilical cord mesenchymal stem cell (UCMSC)-derived CDVs exhibit a biological activity that is similar to UCMSCs or UCMSC-derived EVs. Lastly, we present the establishment of a GMP-compliant process to allow the production of a large number of UCMSC-CDVs in a reproducible manner. GMP-compliant manufacturing of CDVs will facilitate the preclinical and clinical evaluation of these emerging therapeutics in anti-inflammatory or regenerative medicine. This study also represents a crucial step in the development of this novel drug delivery platform based on CDVs.

Next generation of neurological therapeutics: Native and bioengineered extracellular vesicles derived from stem cells

Extracellular vesicles (EVs)-based cell-free therapy, particularly stem cell-derived extracellular vesicles (SC-EVs), offers new insights into treating a series of neurological disorders and becomes a promising candidate for alternative stem cell regenerative therapy. Currently, SC-EVs are considered direct therapeutic agents by themselves and/or dynamic delivery systems as they have a similar regenerative capacity of stem cells to promote neurogenesis and can easily load many functional small molecules to recipient cells in the central nervous system. Meanwhile, as non-living entities, SC-EVs avoid the uncontrollability and manufacturability limitations of live stem cell products in vivo (e.g., low survival rate, immune response, and tumorigenicity) and in vitro (e.g., restricted sources, complex preparation processes, poor quality control, low storage, shipping instability, and ethical controversy) by strict quality control system. Moreover, SC-EVs can be engineered or designed to enhance further overall yield, increase bioactivity, improve targeting, and extend their half-life. Here, this review provides an overview on the biological properties of SC-EVs, and the current progress in the strategies of native or bioengineered SC-EVs for nerve injury repairing is presented. Then we further summarize the challenges of recent research and perspectives for successful clinical application to advance SC-EVs from bench to bedside in neurological diseases.

Extracellular Vesicle Mimetics: Preparation from Top-Down Approaches and Biological Functions

Extracellular vesicles (EVs) have attracted attention as delivery vehicles due to their structure, composition, and unique properties in regeneration and immunomodulation. However, difficulties during production and isolation processes of EVs limit their large-scale clinical applications. EV mimetics (EVMs), prepared via top-down strategies that improve the yield of nanoparticles while retaining biological properties similar to those of EVs have been used to address these limitations. Herein, the preparation of EVMs is reviewed and their characteristics in terms of structure, composition, targeting ability, cellular uptake mechanism, and immunogenicity, as well as their strengths, limitations, and future clinical application prospects as EV alternatives are summarized.

Functional Extracellular Vesicles for Regenerative Medicine

The unique biological characteristics and promising clinical potential of extracellular vesicles (EVs) have galvanized EV applications for regenerative medicine. Recognized as important mediators of intercellular communication, naturally secreted EVs have the potential, as innate biotherapeutics, to promote tissue regeneration. Although EVs have emerged as novel therapeutic agents, challenges related to the clinical transition have led to further functionalization. In recent years, various engineering approaches such as preconditioning, drug loading, and surface modification have been developed to potentiate the therapeutic outcomes of EVs. Also, limitations of natural EVs have been addressed by the development of artificial EVs that offer advantages in terms of production yield and isolation methodologies. In this review, an updated overview of current techniques is provided for the functionalization of natural EVs and recent advances in artificial EVs, particularly in the scope of regenerative medicine.

Novel approaches for long-term lung transplant survival

Allograft failure remains a major barrier in the field of lung transplantation and results primarily from acute and chronic rejection. To date, standard-of-care immunosuppressive regimens have proven unsuccessful in achieving acceptable long-term graft and patient survival. Recent insights into the unique immunologic properties of lung allografts provide an opportunity to develop more effective immunosuppressive strategies. Here we describe advances in our understanding of the mechanisms driving lung allograft rejection and highlight recent progress in the development of novel, lung-specific strategies aimed at promoting long-term allograft survival, including tolerance.

Scalable Production of Extracellular Vesicles and Its Therapeutic Values: A Review

Extracellular vesicles (EVs) are minute vesicles with lipid bilayer membranes. EVs are secreted by cells for intercellular communication. Recently, EVs have received much attention, as they are rich in biological components such as nucleic acids, lipids, and proteins that play essential roles in tissue regeneration and disease modification. In addition, EVs can be developed as vaccines against cancer and infectious diseases, as the vesicle membrane has an abundance of antigenic determinants and virulent factors. EVs for therapeutic applications are typically collected from conditioned media of cultured cells. However, the number of EVs secreted by the cells is limited. Thus, it is critical to devise new strategies for the large-scale production of EVs. Here, we discussed the strategies utilized by researchers for the scalable production of EVs. Techniques such as bioreactors, mechanical stimulation, electrical stimulation, thermal stimulation, magnetic field stimulation, topographic clue, hypoxia, serum deprivation, pH modification, exposure to small molecules, exposure to nanoparticles, increasing the intracellular calcium concentration, and genetic modification have been used to improve the secretion of EVs by cultured cells. In addition, nitrogen cavitation, porous membrane extrusion, and sonication have been utilized to prepare EV-mimetic nanovesicles that share many characteristics with naturally secreted EVs. Apart from inducing EV production, these upscaling interventions have also been reported to modify the EVs’ cargo and thus their functionality and therapeutic potential. In summary, it is imperative to identify a reliable upscaling technique that can produce large quantities of EVs consistently. Ideally, the produced EVs should also possess cargo with improved therapeutic potential.

Engineering Extracellular Microenvironment for Tissue Regeneration

The extracellular microenvironment is a highly dynamic network of biophysical and biochemical elements, which surrounds cells and transmits molecular signals. Extracellular microenvironment controls are of crucial importance for the ability to direct cell behavior and tissue regeneration. In this review, we focus on the different components of the extracellular microenvironment, such as extracellular matrix (ECM), extracellular vesicles (EVs) and growth factors (GFs), and introduce engineering approaches for these components, which can be used to achieve a higher degree of control over cellular activities and behaviors for tissue regeneration. Furthermore, we review the technologies established to engineer native-mimicking artificial components of the extracellular microenvironment for improved regenerative applications. This review presents a thorough analysis of the current research in extracellular microenvironment engineering and monitoring, which will facilitate the development of innovative tissue engineering strategies by utilizing different components of the extracellular microenvironment for regenerative medicine in the future.

Mesenchymal Stromal/Stem Cells and Their Products as a Therapeutic Tool to Advance Lung Transplantation

Lung transplantation (LTx) has become the gold standard treatment for end-stage respiratory failure. Recently, extended lung donor criteria have been applied to decrease the mortality rate of patients on the waiting list. Moreover, ex vivo lung perfusion (EVLP) has been used to improve the number/quality of previously unacceptable lungs. Despite the above-mentioned progress, the morbidity/mortality of LTx remains high compared to other solid organ transplants. Lungs are particularly susceptible to ischemia-reperfusion injury, which can lead to graft dysfunction. Therefore, the success of LTx is related to the quality/function of the graft, and EVLP represents an opportunity to protect/regenerate the lungs before transplantation. Increasing evidence supports the use of mesenchymal stromal/stem cells (MSCs) as a therapeutic strategy to improve EVLP. The therapeutic properties of MSC are partially mediated by secreted factors. Hence, the strategy of lung perfusion with MSCs and/or their products pave the way for a new innovative approach that further increases the potential for the use of EVLP. This article provides an overview of experimental, preclinical and clinical studies supporting the application of MSCs to improve EVLP, the ultimate goal being efficient organ reconditioning in order to expand the donor lung pool and to improve transplant outcomes.

Adipose Stromal/Stem Cell-Derived Extracellular Vesicles: Potential Next-Generation Anti-Obesity Agents

Over the last decade, several compounds have been identified for the treatment of obesity. However, due to the complexity of the disease, many pharmacological interventions have raised concerns about their efficacy and safety. Therefore, it is important to discover new factors involved in the induction/progression of obesity. Adipose stromal/stem cells (ASCs), which are mostly isolated from subcutaneous adipose tissue, are the primary cells contributing to the expansion of fat mass. Like other cells, ASCs release nanoparticles known as extracellular vesicles (EVs), which are being actively studied for their potential applications in a variety of diseases. Here, we focused on the importance of the contribution of ASC-derived EVs in the regulation of metabolic processes. In addition, we outlined the advantages/disadvantages of the use of EVs as potential next-generation anti-obesity agents.

Exosomes derived from adipose-derived stem cells alleviate cigarette smoke-induced lung inflammation and injury by inhibiting alveolar macrophages pyroptosis

Background

Chronic obstructive pulmonary disease (COPD) is a frequently encountered disease condition in clinical practice mainly caused by cigarette smoke (CS). The aim of this study was to investigate the protective roles of human adipose-derived stem cells-derived exosomes (ADSCs-Exo) in CS-induced lung inflammation and injury and explore the underlying mechanism by discovering the effects of ADSCs-Exo on alveolar macrophages (AMs) pyroptosis.

Methods

ADSCs were isolated from human adipose tissues harvested from three healthy donors, and then ADSCs-Exo were isolated. In vivo, 24 age-matched male C57BL/6 mice were exposed to CS for 4 weeks, followed by intratracheal administration of ADSCs-Exo or phosphate buffered saline. In vitro, MH-S cells, derived from mouse AMs, were stimulated by 2% CS extract (CSE) for 24 h, followed by the treatment of ADSCs-Exo or phosphate buffered saline. Pulmonary inflammation was analyzed by detecting pro-inflammatory cells and mediators in the bronchoalveolar lavage fluid. Lung histology was assessed by hematoxylin and eosin staining. Mucus production was determined by Alcian blue-periodic acid-Schiff staining. The profile of AMs pyroptosis was evaluated by detecting the levels of pyroptosis-indicated proteins. The inflammatory response in AMs and the phagocytic activity of AMs were also investigated.

Results

In mice exposed to CS, the levels of pro-inflammatory cells and mediators were significantly increased, mucus production was markedly increased and lung architecture was obviously disrupted. AMs pyroptosis was elevated and AMs phagocytosis was inhibited. However, the administration of ADSCs-Exo greatly reversed these alterations caused by CS exposure. Consistently, in MH-S cells with CSE-induced properties modelling those found in COPD, the cellular inflammatory response was elevated, the pyroptotic activity was upregulated while the phagocytosis was decreased. Nonetheless, these abnormalities were remarkably alleviated by the treatment of ADSCs-Exo.

Conclusions

ADSCs-Exo effectively attenuate CS-induced airway mucus overproduction, lung inflammation and injury by inhibiting AMs pyroptosis. Therefore, hADSCs-Exo may be a promising cell-free therapeutic candidate for CS-induced lung inflammation and injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-01926-w.

NLRP3 downregulation enhances engraftment and functionality of adipose-derived stem cells to alleviate erectile dysfunction in diabetic rats

BACKGROUND

The transplantation of adipose-derived stem cells (ASCs) is a most promising treatment for diabetic erectile dysfunction (DMED). However, the effect of high glucose on the post-transplantation survival of stem cells limits the efficacy of ASCs transplantation. Prolonging the survival time of ASCs in vivo after transplantation is a key issue in the utilization of ASCs for DMED. Herein, we aimed to investigate the therapeutic effect of ASCs by downregulating NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) as well as its mechanism of action in DMED.

METHODS

ASCs were obtained by isolating subcutaneous fat from SD rats and were identified using lipogenic and osteogenic differentiation assays, as well as flow cytometric analysis. The shNLRP3 lentivirus with the best downregulating effect was screened, and shNLRP3 lentivirus (LV-shNLRP3) was transfected into ASCs (ASCs^shNLRP3) to detect apoptosis and the reactive oxygen species (ROS) levels in each group under high glucose conditions. In DMED rats, ASCs^LV-shNLRP3, ASCs^LV-control, or phosphate buffered saline (PBS) were administrated via intra-cavernous injection, and normal rats served as normal controls. One week post-injection, animal imaging was performed to track the ASCs. Four weeks post-injection, erectile function was evaluated by measuring the intra-cavernosal pressure and mean arterial pressure. Corpus cavernosum pyroptosis and endothelial function were examined by western blotting and immunofluorescence.

RESULTS

NLRP3-mediated pyroptosis might be a pathogenic mechanism of ED and DMED. ASCs were isolated successfully. Thereafter, the LV-shNLRP3 with the highest transfection efficiency was selected and used to modify ASCs successfully. LV-shNLRP3 could protect ASCs paracrine function under hyperglycemia through anti-apoptosis and anti-ROS deposition mechanisms. Furthermore, ASCs^LV-shNLRP3 showed an advantage in the suppression of pyroptosis compared to ASCs^LV-control. The ASCs^LV-shNLRP3 group had improved cavernous endothelial function and smooth muscle injury, thus reversing erectile function, and was superior to the ASCs^LV-control group.

CONCLUSIONS

NLRP3 Inflammasome-mediated pyroptosis might be involved in DMED formation. Intra-cavernous injection of ASCs^LV-shNLRP3 could suppress cavernosal pyroptosis, contributing to improved erectile function in DMED rats.

Tropism of Extracellular Vesicles and Cell-Derived Nanovesicles to Normal and Cancer Cells: New Perspectives in Tumor-Targeted Nucleic Acid Delivery

The main advantage of extracellular vesicles (EVs) as a drug carrier system is their low immunogenicity and internalization by mammalian cells. EVs are often considered a cell-specific delivery system, but the production of preparative amounts of EVs for therapeutic applications is challenging due to their laborious isolation and purification procedures. Alternatively, mimetic vesicles prepared from the cellular plasma membrane can be used in the same way as natural EVs. For example, a cytoskeleton-destabilizing agent, such as cytochalasin B, allows the preparation of membrane vesicles by a series of centrifugations. Here, we prepared cytochalasin-B-inducible nanovesicles (CINVs) of various cellular origins and studied their tropism in different mammalian cells. We observed that CINVs derived from human endometrial mesenchymal stem cells exhibited an enhanced affinity to epithelial cancer cells compared to myeloid, lymphoid or neuroblastoma cancer cells. The dendritic cell-derived CINVs were taken up by all studied cell lines with a similar efficiency that differed from the behavior of DC-derived EVs. The ability of cancer cells to internalize CINVs was mainly determined by the properties of recipient cells, and the cellular origin of CINVs was less important. In addition, receptor-mediated interactions were shown to be necessary for the efficient uptake of CINVs. We found that CINVs, derived from late apoptotic/necrotic cells (aCINVs) are internalized by in myelogenous (K562) 10-fold more efficiently than CINVs, and interact much less efficiently with melanocytic (B16) or epithelial (KB-3-1) cancer cells. Finally, we found that CINVs caused a temporal and reversible drop of the rate of cell division, which restored to the level of control cells with a 24 h delay.

Exosomes in chronic respiratory diseases

Exosomes are nano-sized vesicles released by almost all cell types, with a central role as mediators of intercellular communication. In addition to physiological conditions, these extracellular vesicles seem to play a pivotal role in inflammatory processes. This assumption offers the opportunity to study exosomes as promising biomarkers and therapeutic tools for chronic respiratory disorders. Indeed, although it is well-known that at the basis of conditions like asthma, chronic obstructive pulmonary disease, alpha-1 antitrypsin deficiency and idiopathic pulmonary fibrosis there is a dysregulated inflammatory process, an unequivocal correlation between different phenotypes and their pathophysiological mechanisms has not been established yet. In this review, we report and discuss some of the most significant studies on exosomes from body fluids of subjects affected by airway diseases. Furthermore, the most widespread techniques for exosome isolation and characterization are described. Further studies are needed to answer the unresolved questions about the functional link between exosomes and chronic respiratory diseases.

Artificial exosomes for translational nanomedicine

Exosomes are lipid bilayer membrane vesicles and are emerging as competent nanocarriers for drug delivery. The clinical translation of exosomes faces many challenges such as massive production, standard isolation, drug loading, stability and quality control. In recent years, artificial exosomes are emerging based on nanobiotechnology to overcome the limitations of natural exosomes. Major types of artificial exosomes include 'nanovesicles (NVs)', 'exosome-mimetic (EM)' and 'hybrid exosomes (HEs)', which are obtained by top-down, bottom-up and biohybrid strategies, respectively. Artificial exosomes are powerful alternatives to natural exosomes for drug delivery. Here, we outline recent advances in artificial exosomes through nanobiotechnology and discuss their strengths, limitations and future perspectives. The development of artificial exosomes holds great values for translational nanomedicine.

Stem cell therapy for chronic obstructive pulmonary disease

ABSTRACT

Chronic obstructive pulmonary disease (COPD), characterized by persistent and not fully reversible airflow restrictions, is currently one of the most widespread chronic lung diseases in the world. The most common symptoms of COPD are cough, expectoration, and exertional dyspnea. Although various strategies have been developed during the last few decades, current medical treatment for COPD only focuses on the relief of symptoms, and the reversal of lung function deterioration and improvement in patient's quality of life are very limited. Consequently, development of novel effective therapeutic strategies for COPD is urgently needed. Stem cells were known to differentiate into a variety of cell types and used to regenerate lung parenchyma and airway structures. Stem cell therapy is a promising therapeutic strategy that has the potential to restore the lung function and improve the quality of life in patients with COPD. This review summarizes the current state of knowledge regarding the clinical research on the treatment of COPD with mesenchymal stem cells (MSCs) and aims to update the understanding of the role of MSCs in COPD treatment, which may be helpful for developing effective therapeutic strategies in clinical settings.

Adipose-Derived Stem Cells Secretome and Its Potential Application in "Stem Cell-Free Therapy"

Adipose-derived stem cells (ASCs) secrete many cytokines, proteins, growth factors, and extracellular vesicles with beneficial outcomes that can be used in regenerative medicine. It has great potential, and the development of new treatment strategies using the ASCs secretome is of global interest. Besides cytokines, proteins, and growth factors, the therapeutic effect of secretome is hidden in non-coding RNAs such as miR-21, miR-24, and miR-26 carried via exosomes secreted by adequate cells. The whole secretome, including ASC-derived exosomes (ASC-exos) has been proven in many studies to have immunomodulatory, proangiogenic, neurotrophic, and epithelization activity and can potentially be used for neurodegenerative, cardiovascular, respiratory, inflammatory, and autoimmune diseases as well as wound healing treatment. Due to limitations in the use of stem cells in cell-based therapy, its secretome with emphasis on exosomes seems to be a reasonable and safer alternative with increased effectiveness and fewer side effects. Moreover, the great advantage of cell-free therapy is the possibility of biobanking the ASCs secretome. In this review, we focus on the current state of knowledge on the use of the ASCs secretome in stem cell-free therapy.

Effects of Mesenchymal Stromal Cell-Derived Extracellular Vesicles in Lung Diseases: Current Status and Future Perspectives

Mesenchymal stromal cells (MSCs) as a kind of pluripotent adult stem cell have shown great therapeutic potential in relation to many diseases in anti-inflammation and regeneration. The results of preclinical experiments and clinical trials have demonstrated that MSC-derived secretome possesses immunoregulatory and reparative abilities and that this secretome is capable of modulating innate and adaptive immunity and reprograming the metabolism of recipient cells via paracrine mechanisms. It has been recognized that MSC-derived secretome, including soluble proteins (cytokines, chemokines, growth factors, proteases), extracellular vesicles (EVs) and organelles, plays a key role in tissue repair and regeneration in bronchopulmonary dysplasia, acute respiratory distress syndrome (ARDS), bronchial asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), pulmonary arterial hypertension, and silicosis. This review summarizes the known functions of MSC-EV modulation in lung diseases, coupled with the future challenges of MSC-EVs as a new pharmaceutical agent. The identification of underlying mechanisms for MSC-EV might provide a new direction for MSC-centered treatment in lung diseases.Graphical abstract.

Mesenchymal Stem Cell Derived Exosomes: a Nano Platform for Therapeutics and Drug Delivery in Combating COVID-19

The recent pandemic situation transpired due to coronavirus novel strain SARS-CoV-2 has become a global concern. This human coronavirus (HCov-19) has put the world on high alert as the numbers of confirmed cases are continuously increasing. The world is now fighting against this deadly virus and is leaving no stone unturned to find effective treatments through testing of various available drugs, including those effective against flu, malaria, etc. With an urgent need for the development of potential strategies, two recent studies from China using Mesenchymal Stem Cells (MSCs) to treat COVID-19 pneumonia have shed some light on a potential cure for the COVID-19 infected patients. However, MSCs, despite being used in various other clinical trials have always been questioned for their tendency to aggregate or form clumps in the injured or disease microenvironment. It has also been reported in various studies that exosomes secreted by these MSCs, contribute towards the cell’s biological and therapeutic efficacy. There have been reports evaluating the safety and feasibility of these exosomes in various lung diseases, thereby proposing them as a cell-free therapeutic agent. Also, attractive features like cell targeting, low-immunogenicity, safety, and high biocompatibility distinguish these exosomes from other synthetic nano-vesicles and thus potentiate their role as a drug delivery nano-platform. Building upon these observations, herein, efforts are made to give an overview of stem cell-derived exosomes as an appealing therapeutic agent and drug delivery nano-carrier. In this review, we briefly recapitulate the recent evidence and developments in understanding exosomes as a promising candidate for novel nano-intervention in the current pandemic scenario. Furthermore, this review will highlight and discuss mechanistic role of exosomes to combat severe lung pathological conditions. We have also attempted to dwell into the nano-formulation of exosomes for its better applicability, storage, and stability thereby conferring them as off the shelf therapeutic.

Mesenchymal Stromal Cell-Derived Extracellular Vesicles in Lung Diseases: Current Status and Perspectives

Extracellular vesicles (EVs) have emerged as a potential therapy for several diseases. These plasma membrane-derived fragments are released constitutively by virtually all cell types-including mesenchymal stromal cells (MSCs)-under stimulation or following cell-to-cell interaction, which leads to activation or inhibition of distinct signaling pathways. Based on their size, intracellular origin, and secretion pathway, EVs have been grouped into three main populations: exosomes, microvesicles (or microparticles), and apoptotic bodies. Several molecules can be found inside MSC-derived EVs, including proteins, lipids, mRNA, microRNAs, DNAs, as well as organelles that can be transferred to damaged recipient cells, thus contributing to the reparative process and promoting relevant anti-inflammatory/resolutive actions. Indeed, the paracrine/endocrine actions induced by MSC-derived EVs have demonstrated therapeutic potential to mitigate or even reverse tissue damage, thus raising interest in the regenerative medicine field, particularly for lung diseases. In this review, we summarize the main features of EVs and the current understanding of the mechanisms of action of MSC-derived EVs in several lung diseases, such as chronic obstructive pulmonary disease (COPD), pulmonary infections [including coronavirus disease 2019 (COVID-19)], asthma, acute respiratory distress syndrome (ARDS), idiopathic pulmonary fibrosis (IPF), and cystic fibrosis (CF), among others. Finally, we list a number of limitations associated with this therapeutic strategy that must be overcome in order to translate effective EV-based therapies into clinical practice.

Human umbilical cord mesenchymal stem cell-derived extracellular vesicles ameliorate airway inflammation in a rat model of chronic obstructive pulmonary disease (COPD)

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is an incurable and debilitating chronic disease characterized by progressive airflow limitation associated with abnormal levels of tissue inflammation. Therefore, stem cell-based approaches to tackle the condition are currently a focus of regenerative therapies for COPD. Extracellular vesicles (EVs) released by all cell types are crucially involved in paracrine, extracellular communication. Recent advances in the field suggest that stem cell-derived EVs possess a therapeutic potential which is comparable to the cells of their origin.

METHODS

In this study, we assessed the potential anti-inflammatory effects of human umbilical cord mesenchymal stem cell (hUC-MSC)-derived EVs in a rat model of COPD. EVs were isolated from hUC-MSCs and characterized by the transmission electron microscope, western blotting, and nanoparticle tracking analysis. As a model of COPD, male Sprague-Dawley rats were exposed to cigarette smoke for up to 12 weeks, followed by transplantation of hUC-MSCs or application of hUC-MSC-derived EVs. Lung tissue was subjected to histological analysis using haematoxylin and eosin staining, Alcian blue-periodic acid-Schiff (AB-PAS) staining, and immunofluorescence staining. Gene expression in the lung tissue was assessed using microarray analysis. Statistical analyses were performed using GraphPad Prism 7 version 7.0 (GraphPad Software, USA). Student's t test was used to compare between 2 groups. Comparison among more than 2 groups was done using one-way analysis of variance (ANOVA). Data presented as median ± standard deviation (SD).

RESULTS

Both transplantation of hUC-MSCs and application of EVs resulted in a reduction of peribronchial and perivascular inflammation, alveolar septal thickening associated with mononuclear inflammation, and a decreased number of goblet cells. Moreover, hUC-MSCs and EVs ameliorated the loss of alveolar septa in the emphysematous lung of COPD rats and reduced the levels of NF-κB subunit p65 in the tissue. Subsequent microarray analysis revealed that both hUC-MSCs and EVs significantly regulate multiple pathways known to be associated with COPD.

CONCLUSIONS

In conclusion, we show that hUC-MSC-derived EVs effectively ameliorate by COPD-induced inflammation. Thus, EVs could serve as a new cell-free-based therapy for the treatment of COPD.

Potential application of mesenchymal stem cells and their exosomes in lung injury: an emerging therapeutic option for COVID-19 patients

The COVID-19 pandemic has negatively impacted the global public health and the international economy; therefore, there is an urgent need for an effective therapy to treat COVID-19 patients. Mesenchymal stem cells (MSCs) have been proposed as an emerging therapeutic option for the SARS-CoV-2 infection. Recently, numerous clinical trials have been registered to examine the safety and efficacy of different types of MSCs and their exosomes for treating COVID-19 patients, with less published data on the mechanism of action. Although there is no approved effective therapy for COVID-19 as of yet, MSC therapies showed an improvement in the treatment of some COVID-19 patients. MSC’s therapeutic effect is displayed in their ability to reduce the cytokine storm, enhance alveolar fluid clearance, and promote epithelial and endothelial recovery; however, the safest and most effective route of MSC delivery remains unclear. The use of poorly characterized MSC products remains one of the most significant drawbacks of MSC-based therapy, which could theoretically promote the risk for thromboembolism. Optimizing the clinical-grade production of MSCs and establishing a consensus on registered clinical trials based on cell-product characterization and mode of delivery would aid in laying the foundation for a safe and effective therapy in COVID-19. In this review, we shed light on the mechanistic view of MSC therapeutic role based on preclinical and clinical studies on acute lung injury and ARDS; therefore, offering a unique correlation and applicability in COVID-19 patients. We further highlight the challenges and opportunities in the use of MSC-based therapy.

EVs and Bioengineering: From Cellular Products to Engineered Nanomachines

Extracellular vesicles (EVs) are natural carriers produced by many different cell types that have a plethora of functions and roles that are still under discovery. This review aims to be a compendium on the current advancement in terms of EV modifications and re-engineering, as well as their potential use in nanomedicine. In particular, the latest advancements on artificial EVs are discussed, with these being the frontier of nanomedicine-based therapeutics. The first part of this review gives an overview of the EVs naturally produced by cells and their extraction methods, focusing on the possibility to use them to carry desired cargo. The main issues for the production of the EV-based carriers are addressed, and several examples of the techniques used to upload the cargo are provided. The second part focuses on the engineered EVs, obtained through surface modification, both using direct and indirect methods, i.e., engineering of the parental cells. Several examples of the current literature are proposed to show the broad variety of engineered EVs produced thus far. In particular, we also report the possibility to engineer the parental cells to produce cargo-loaded EVs or EVs displaying specific surface markers. The third and last part focuses on the most recent advancements based on synthetic and chimeric EVs and the methods for their production. Both top-down or bottom-up techniques are analyzed, with many examples of applications.

Lactobacillus plantarum-derived extracellular vesicles induce anti-inflammatory M2 macrophage polarization in vitro

Probiotics offer various health benefits. Lactobacillus plantarum has been used for decades to enhance human intestinal mucosal immunity and improve skin barrier integrity. Extracellular vesicles (EVs) derived from eukaryotic or prokaryotic cells have been recognized as efficient carriers for delivery of biomolecules to recipient cells, and to efficiently regulate human pathophysiology. However, the mechanism underlying the beneficial effects of probiotic bacteria-derived EVs on human skin is unclear. Herein, we investigated how L. plantarum-derived EVs (LEVs) exert beneficial effects on human skin by examining the effect of LEVs on cutaneous immunity, particularly on macrophage polarization. LEVs promoted differentiation of human monocytic THP1 cells towards an anti-inflammatory M2 phenotype, especially M2b, by inducing biased expression of cell-surface markers and cytokines associated with M2 macrophages. Pre- or post-treatment with LEVs under inflammatory M1 macrophage-favouring conditions, induced by LPS and interferon-γ, inhibited M1-associated surface marker, HLA-DRα expression. Moreover, LEV treatment significantly induced expression of macrophage-characteristic cytokines, IL-1β, GM-CSF and the representative anti-inflammatory cytokine, IL-10, in human skin organ cultures. Hence, LEVs can trigger M2 macrophage polarization in vitro, and induce an anti-inflammatory phenomenon in the human skin, and may be a potent anti-inflammatory strategy to alleviate hyperinflammatory skin conditions.

Mesenchymal stromal cell-derived small extracellular vesicles restore lung architecture and improve exercise capacity in a model of neonatal hyperoxia-induced lung injury

Early administration of mesenchymal stromal cell (MSC)-derived small extracellular vesicles (MEx) has shown considerable promise in experimental models of bronchopulmonary dysplasia (BPD). However, the ability of MEx to reverse the long-term pulmonary complications associated with established BPD remains unknown. In this study, MEx were isolated from media conditioned by human Wharton’s Jelly-derived MSC cultures. Newborn mice (FVB strain) were exposed to hyperoxia (HYRX (75% O2)) before returning to room air at postnatal day 14 (PN14). Following prolonged HYRX-exposure, animals received a single MEx dose at PN18 or serial MEx treatments at PN18-39 (“late” intervention). This group was compared to animals that received an early single MEx dose at PN4 (“early” intervention). Animals were harvested at PN28 or 60 for assessment of pulmonary parameters. We found that early and late MEx interventions effectively ameliorated core features of HYRX-induced neonatal lung injury, improving alveolar simplification, pulmonary fibrosis, vascular remodelling and blood vessel loss. Exercise capacity testing and assessment of pulmonary hypertension (PH) showed functional improvements following both early and late MEx interventions. In conclusion, delivery of MEx following prolonged HYRX-exposure improves core features of experimental BPD, restoring lung architecture, decreasing pulmonary fibrosis and vascular muscularization, ameliorating PH and improving exercise capacity. Taken together, delivery of MEx may not only be effective in the immediate neonatal period to prevent the development of BPD but may provide beneficial effects for the management and potentially the reversal of cardiorespiratory complications in infants and children with established BPD.

Extracellular vesicles: novel communicators in lung diseases

The lung is the organ with the highest vascular density in the human body. It is therefore perceivable that the endothelium of the lung contributes significantly to the circulation of extracellular vesicles (EVs), which include exosomes, microvesicles, and apoptotic bodies. In addition to the endothelium, EVs may arise from alveolar macrophages, fibroblasts and epithelial cells. Because EVs harbor cargo molecules, such as miRNA, mRNA, and proteins, these intercellular communicators provide important insight into the health and disease condition of donor cells and may serve as useful biomarkers of lung disease processes. This comprehensive review focuses on what is currently known about the role of EVs as markers and mediators of lung pathologies including COPD, pulmonary hypertension, asthma, lung cancer and ALI/ARDS. We also explore the role EVs can potentially serve as therapeutics for these lung diseases when released from healthy progenitor cells, such as mesenchymal stem cells.

Stem cell derived exosomes-based therapy for acute lung injury and acute respiratory distress syndrome: A novel therapeutic strategy

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a common critical disease which can be caused by multiple pathological factors in clinic. However, feasible and effective treatment strategies of ALI/ARDS are limited. At present, the beneficial effect of stem cells (SCs)-based therapeutic strategies for ALI/ARDS can be attributed to paracrine. Exosomes, as a paracrine product, are regarded as a critical regulatory mediator. Furthermore, substantial evidence has indicated that exosomes from SCs can transmit bioactive components including genetic material and protein to the recipient cells and provide a protective effect. The protective role is played through a series of process including inflammation modulation, the reconstruction of alveolar epithelium and endothelium, and pulmonary fibrosis prevention. Therefore, SCs derived exosomes have the potential to be used for therapeutic strategies for ALI/ARDS. In this review, we discuss the present understanding of SCs derived exosomes related to ALI/ARDS and provide insights for developing a cell-free strategy for treating ALI/ARDS.

MSC Based Therapies-New Perspectives for the Injured Lung

Chronic lung diseases pose a tremendous global burden. At least one in four people suffer from severe pulmonary sequelae over the course of a lifetime. Despite substantial improvements in therapeutic interventions, persistent alleviation of clinical symptoms cannot be offered to most patients affected to date. Despite broad discrepancies in origins and pathomechanisms, the important disease entities all have in common the pulmonary inflammatory response which is central to lung injury and structural abnormalities. Mesenchymal stem cells (MSC) attract particular attention due to their broadly acting anti-inflammatory and regenerative properties. Plenty of preclinical studies provided congruent and convincing evidence that MSC have the therapeutic potential to alleviate lung injuries across ages. These include the disease entities bronchopulmonary dysplasia, asthma and the different forms of acute lung injury and chronic pulmonary diseases in adulthood. While clinical trials are so far restricted to pioneering trials on safety and feasibility, preclinical results point out possibilities to boost the therapeutic efficacy of MSC application and to take advantage of the MSC secretome. The presented review summarizes the most recent advances and highlights joint mechanisms of MSC action across disease entities which provide the basis to timely tackle this global disease burden.

Bioinspired exosome-like therapeutics and delivery nanoplatforms

Exosomes have emerged as appealing candidate therapeutic agents and delivery nanoplatforms due to their endogenous features and unique biological properties. However, obstacles such as low isolation yield, considerable complexity and potential safety concerns, and inefficient drug payload substantially hamper their therapeutic applicability. To this end, developing bioinspired exosome-like nanoparticles has become a promising area to overcome certain limitations of their natural counterparts. Synthetically fabrication of exosome-like nanoparticles that harbor only crucial components of exosomes through controllable protocols strongly increases the pharmaceutical acceptability of these vesicles. Assembly of exosome-like nanovesicles derived from producer cells allows for a promising strategy for scale-up production. To improve the loading capability and delivery efficiency of exosomes, hybrid exosome-like nanovesicles and membrane-camouflaged nanoparticles towards better bridging synthetic nanocarriers with natural exosomes could be designed. Building off these observations, herein, efforts are made to give an overview of bioinspired exosome-like therapeutics and delivery nanoplatforms. We briefly recapitulate the recent advance in exosome biology with focus on tailoring exosomes as therapeutics and delivery vehicles. Furthermore, we elaborately discuss the biomimicry methodologies for preparation of exosome-like nanoparticles with special emphasis on offering insights into strategies for rational design of exosome-like biomaterials as effective and safe therapeutics and delivery nanoplatforms.

Derivation of Cell-Engineered Nanovesicles from Human Induced Pluripotent Stem Cells and Their Protective Effect on the Senescence of Dermal Fibroblasts

Stem cells secrete numerous paracrine factors, such as cytokines, growth factors, and extracellular vesicles. As a kind of extracellular vesicle (EV), exosomes produced in the endosomal compartment of eukaryotic cells have recently emerged as a biomedical material for regenerative medicine, because they contain many valuable contents that are derived from the host cells, and can stably deliver those contents to other recipient cells. Although we have previously demonstrated the beneficial effects of human induced potent stem cell-derived exosomes (iPSC-Exo) on the aging of skin fibroblasts, low production yield has remained an obstacle for clinical applications. In this study, we generated cell-engineered nanovesicles (CENVs) by serial extrusion of human iPSCs through membrane filters with diminishing pore sizes, and explored whether the iPSC-CENV ameliorates physiological alterations of human dermal fibroblasts (HDFs) that occur by natural senescence. The iPSC-CENV exhibited similar characteristics to the iPSC-Exo, while the production yield was drastically increased compared to that of iPSC-derived EVs, including exosomes. The proliferation and migration of both young and senescent HDFs were stimulated by the treatment with iPSC-CENVs. In addition, it was revealed that the iPSC-CNEV restored senescence-related alterations of gene expression. Treatment with iPSC-CENVs significantly reduced the activity of senescence-associated-β-galactosidase (SA-β-Gal) in senescent HDFs, as well as suppressing the elevated expression of p53 and p21, key factors involved in cell cycle arrest, apoptosis, and cellular senescence signaling pathways. Taken together, these results suggest that iPSC-CENV could provide an excellent alternative to iPSC-exo, and be exploited as a resource for the treatment of signs of skin aging.

Biofabrication of Cell-Derived Nanovesicles: A Potential Alternative to Extracellular Vesicles for Regenerative Medicine

Extracellular vesicles (EVs) are mediators of intercellular communication by transferring functional biomolecules from their originating cells to recipient cells. This intrinsic ability has gained EVs increased scientific interest in their use as a direct therapeutic in the field of regenerative medicine or as vehicles for drug delivery. EVs derived from stem cells or progenitor cells can act as paracrine mediators to promote repair and regeneration of damaged tissues. Despite substantial research efforts into EVs for various applications, their use remains limited by the lack of highly efficient and scalable production methods. Here, we present the biofabrication of cell-derived nanovesicles (NVs) as a scalable, efficient, and cost-effective production alternative to EVs. We demonstrate that NVs have a comparable size and morphology as EVs, but lack standard EV (surface) markers. Additionally, in vitro uptake experiments show that human fetal cardiac fibroblast, endothelial cells, and cardiomyocyte progenitor cells internalize NVs. We observed that cardiac progenitor cell-derived NVs and EVs are capable of activating mitogen-activated protein kinase 1/2 (MAPK1/2)-extracellular signal-regulated kinase, and that both NVs and EVs derived from A431 and HEK293 cells can functionally deliver Cre-recombinase mRNA or protein to other cells. These observations indicate that NVs may have similar functional properties as EVs. Therefore, NVs have the potential to be applied for therapeutic delivery and regenerative medicine purposes.

The potential of mesenchymal stem cell therapy for chronic lung disease

Introduction: Mesenchymal stem/stromal cells (MSCs) have been shown to improve lung function and survival in chronic inflammatory lung diseases, including asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), pulmonary arterial hypertension (PAH), and silicosis.Areas covered: This review covers rationale for the use of MSC therapy, along with preclinical studies and clinical trials with MSC therapy in chronic lung diseases.Expert opinion: MSC therapy holds promise for the treatment of chronic lung diseases, mainly when administered at early stages. In clinical trials, MSC administration was safe, but associated with limited effects on clinical outcomes. Further studies are required to elucidate unresolved issues, including optimal MSC source and dose, route of administration, and frequency (single vs. multiple-dose regimens). A better understanding of the mechanisms of MSC action, local microenvironment of each disease, and development of strategies to potentiate the beneficial effects of MSCs may improve outcomes.

Enhancement of therapeutic potential of mesenchymal stem cell-derived extracellular vesicles

After the initial investigations into applications of mesenchymal stem cells (MSCs) for cell therapy, there was increased interest in their secreted soluble factors. Following studies of MSCs and their secreted factors, extracellular vesicles (EVs) released from MSCs have emerged as a new mode of intercellular crosstalk. MSC-derived EVs have been identified as essential signaling mediators under both physiological and pathological conditions, and they appear to be responsible for many of the therapeutic effects of MSCs. In several in vitro and in vivo models, EVs have been observed to have supportive functions in modulating the immune system, mainly mediated by EV-associated proteins and nucleic acids. Moreover, stimulation of MSCs with biophysical or biochemical cues, including EVs from other cells, has been shown to influence the contents and biological activities of subsequent MSC-derived EVs. This review provides on overview of the contents of MSC-derived EVs in terms of their supportive effects, and it provides different perspectives on the manipulation of MSCs to improve the secretion of EVs and subsequent EV-mediated activities. In this review, we discuss the possibilities for manipulating MSCs for EV-based cell therapy and for using EVs to affect the expression of elements of interest in MSCs. In this way, we provide a clear perspective on the state of the art of EVs in cell therapy focusing on MSCs, and we raise pertinent questions and suggestions for knowledge gaps to be filled.

Strategies for the use of Extracellular Vesicles for the Delivery of Therapeutics

Extracellular vesicles (EVs) are nanosized, membrane-bound vesicles released from eukaryotic and prokaryotic cells that can transport cargo containing DNA, RNA, lipids and proteins, between cells as a means of intercellular communication. Although EVs were initially considered to be cellular debris deprived of any essential biological functions, emerging literature highlights the critical roles of EVs in the context of intercellular signaling, maintenance of tissue homeostasis, modulation of immune responses, inflammation, cancer progression, angiogenesis, and coagulation under both physiological and pathological states. Based on the ability of EVs to shuttle proteins, lipids, carbohydrates, mRNAs, long non-coding RNAs (lncRNAs), microRNAs, chromosomal DNA, and mitochondrial DNA into target cells, the presence and content of EVs in biofluids have been exploited for biomarker research in the context of diagnosis, prognosis and treatment strategies. Additionally, owing to the characteristics of EVs such as stability in circulation, biocompatibility as well as low immunogenicity and toxicity, these vesicles have become attractive systems for the delivery of therapeutics. More recently, EVs are increasingly being exploited as conduits for delivery of therapeutics for anticancer strategies, immunomodulation, targeted drug delivery, tissue regeneration, and vaccination. In this review, we highlight and discuss the multiple strategies that are employed for the use of EVs as delivery vehicles for therapeutic agents, including the potential advantages and challenges involved. Graphical abstract.

Mesenchymal stromal cell-derived nanovesicles ameliorate bacterial outer membrane vesicle-induced sepsis via IL-10

Background

Sepsis remains a source of high mortality in hospitalized patients despite proper antibiotic approaches. Encouragingly, mesenchymal stromal cells (MSCs) and their produced extracellular vesicles (EVs) have been shown to elicit anti-inflammatory effects in multiple inflammatory conditions including sepsis. However, EVs are generally released from mammalian cells in relatively low amounts, and high-yield isolation of EVs is still challenging due to a complicated procedure. To get over these limitations, vesicles very similar to EVs can be produced by serial extrusions of cells, after which they are called nanovesicles (NVs). We hypothesized that MSC-derived NVs can attenuate the cytokine storm induced by bacterial outer membrane vesicles (OMVs) in mice, and we aimed to elucidate the mechanism involved.

Methods

NVs were produced from MSCs by the breakdown of cells through serial extrusions and were subsequently floated in a density gradient. Morphology and the number of NVs were analyzed by transmission electron microscopy and nanoparticle tracking analysis. Mice were intraperitoneally injected with Escherichia coli-derived OMVs to establish sepsis, and then injected with 2 × 10⁹ NVs. Innate inflammation was assessed in peritoneal fluid and blood through investigation of infiltration of cells and cytokine production. The biodistribution of NVs labeled with Cy7 dye was analyzed using near-infrared imaging.

Results

Electron microscopy showed that NVs have a nanometer-size spherical shape and harbor classical EV marker proteins. In mice, NVs inhibited eye exudates and hypothermia, signs of a systemic cytokine storm, induced by intraperitoneal injection of OMVs. Moreover, NVs significantly suppressed cytokine release into the systemic circulation, as well as neutrophil and monocyte infiltration in the peritoneum. The protective effect of NVs was significantly reduced by prior treatment with anti-interleukin (IL)-10 monoclonal antibody. In biodistribution study, NVs spread to the whole mouse body and localized in the lung, liver, and kidney at 6 h.

Conclusions

Taken together, these data indicate that MSC-derived NVs have beneficial effects in a mouse model of sepsis by upregulating the IL-10 production, suggesting that artificial NVs may be novel EV-mimetics clinically applicable to septic patients.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1352-4) contains supplementary material, which is available to authorized users.

Molecular Mechanisms Responsible for Therapeutic Potential of Mesenchymal Stem Cell-Derived Secretome

Mesenchymal stem cell (MSC)-sourced secretome, defined as the set of MSC-derived bioactive factors (soluble proteins, nucleic acids, lipids and extracellular vesicles), showed therapeutic effects similar to those observed after transplantation of MSCs. MSC-derived secretome may bypass many side effects of MSC-based therapy, including unwanted differentiation of engrafted MSCs. In contrast to MSCs which had to be expanded in culture to reach optimal cell number for transplantation, MSC-sourced secretome is immediately available for treatment of acute conditions, including fulminant hepatitis, cerebral ischemia and myocardial infarction. Additionally, MSC-derived secretome could be massively produced from commercially available cell lines avoiding invasive cell collection procedure. In this review article we emphasized molecular and cellular mechanisms that were responsible for beneficial effects of MSC-derived secretomes in the treatment of degenerative and inflammatory diseases of hepatobiliary, respiratory, musculoskeletal, gastrointestinal, cardiovascular and nervous system. Results obtained in a large number of studies suggested that administration of MSC-derived secretomes represents a new, cell-free therapeutic approach for attenuation of inflammatory and degenerative diseases. Therapeutic effects of MSC-sourced secretomes relied on their capacity to deliver genetic material, growth and immunomodulatory factors to the target cells enabling activation of anti-apoptotic and pro-survival pathways that resulted in tissue repair and regeneration.