Mesenchymal Stem Cell Derived Biocompatible Membrane Vesicles Demonstrate Immunomodulatory Activity Inhibiting Activation and proliferation of Human Mononuclear Cells

Extracellular Vesicles as a Translational Approach for the Treatment of COVID-19 Disease: An Updated Overview

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a global pandemic in the years 2020-2022. With a high prevalence, an easy route of transmission, and a long incubation time, SARS-CoV-2 spread quickly and affected public health and socioeconomic conditions. Several points need to be elucidated about its mechanisms of infection, in particular, its capability to evade the immune system and escape from neutralizing antibodies. Extracellular vesicles (EVs) are phospholipid bilayer-delimited particles that are involved in cell-to-cell communication; they contain biological information such as miRNAs, proteins, nucleic acids, and viral components. Abundantly released from biological fluids, their dimensions are highly variable, which are used to divide them into exosomes (40 to 150 nm), microvesicles (40 to 10,000 nm), and apoptotic bodies (100-5000 nm). EVs are involved in many physiological and pathological processes. In this article, we report the latest evidence about EVs' roles in viral infections, focusing on the dual role of exosomes in promoting and inhibiting SARS-CoV-2 infection. The involvement of mesenchymal stromal/stem cells (MSCs) and MSC-derived EVs in COVID-19 treatment, such as the use of translational exosomes as a diagnostical/therapeutic approach, is also investigated. These elucidations could be useful to better direct the discovery of future diagnostical tools and new exosome-derived COVID-19 biomarkers, which can help achieve optimal therapeutic interventions and implement future vaccine strategies.

Extracellular Vesicles in Hepatobiliary Health and Disease

Extracellular vesicles (EVs) are membrane-bound nanoparticles released by cells and are an important means of intercellular communication in physiological and pathological states. We provide an overview of recent advances in the understanding of EV biogenesis, cargo selection, recipient cell effects, and key considerations in isolation and characterization techniques. Studies on the physiological role of EVs have relied on cell-based model systems due to technical limitations of studying endogenous nanoparticles in vivo . Several recent studies have elucidated the mechanistic role of EVs in liver diseases, including nonalcoholic fatty liver disease, viral hepatitis, cholestatic liver disease, alcohol-associated liver disease, acute liver injury, and liver cancers. Employing disease models and human samples, the biogenesis of lipotoxic EVs downstream of endoplasmic reticulum stress and microvesicles via intracellular activation stress signaling are discussed in detail. The diverse cargoes of EVs including proteins, lipids, and nucleic acids can be enriched in a disease-specific manner. By carrying diverse cargo, EVs can directly confer pathogenic potential, for example, recruitment and activation of monocyte-derived macrophages in NASH and tumorigenicity and chemoresistance in hepatocellular carcinoma. We discuss the pathogenic role of EVs cargoes and the signaling pathways activated by EVs in recipient cells. We review the literature that EVs can serve as biomarkers in hepatobiliary diseases. Further, we describe novel approaches to engineer EVs to deliver regulatory signals to specific cell types, and thus use them as therapeutic shuttles in liver diseases. Lastly, we identify key lacunae and future directions in this promising field of discovery and development. © 2023 American Physiological Society. Compr Physiol 13:4631-4658, 2023.

Pretreated Mesenchymal Stem Cells and Their Secretome: Enhanced Immunotherapeutic Strategies

Mesenchymal stem cells (MSCs) with self-renewing, multilineage differentiation and immunomodulatory properties, have been extensively studied in the field of regenerative medicine and proved to have significant therapeutic potential in many different pathological conditions. The role of MSCs mainly depends on their paracrine components, namely secretome. However, the components of MSC-derived secretome are not constant and are affected by the stimulation MSCs are exposed to. Therefore, the content and composition of secretome can be regulated by the pretreatment of MSCs. We summarize the effects of different pretreatments on MSCs and their secretome, focusing on their immunomodulatory properties, in order to provide new insights for the therapeutic application of MSCs and their secretome in inflammatory immune diseases.

Extracellular vesicles and their cells of origin: Open issues in autoimmune diseases

The conventional therapeutic approaches to treat autoimmune diseases through suppressing the immune system, such as steroidal and non-steroidal anti-inflammatory drugs, are not adequately practical. Moreover, these regimens are associated with considerable complications. Designing tolerogenic therapeutic strategies based on stem cells, immune cells, and their extracellular vesicles (EVs) seems to open a promising path to managing autoimmune diseases' vast burden. Mesenchymal stem/stromal cells (MSCs), dendritic cells, and regulatory T cells (Tregs) are the main cell types applied to restore a tolerogenic immune status; MSCs play a more beneficial role due to their amenable properties and extensive cross-talks with different immune cells. With existing concerns about the employment of cells, new cell-free therapeutic paradigms, such as EV-based therapies, are gaining attention in this field. Additionally, EVs' unique properties have made them to be known as smart immunomodulators and are considered as a potential substitute for cell therapy. This review provides an overview of the advantages and disadvantages of cell-based and EV-based methods for treating autoimmune diseases. The study also presents an outlook on the future of EVs to be implemented in clinics for autoimmune patients.

Dendritic Cell-Derived Artificial Microvesicles Inhibit RLS40 Lymphosarcoma Growth in Mice via Stimulation of Th1/Th17 Immune Response

Cell-free antitumor vaccines represent a promising approach to immunotherapy of cancer. Here, we compare the antitumor potential of cell-free vaccines based on microvesicles derived from dendritic cells (DCs) with DC- and cationic-liposome-based vaccines using a murine model of drug-resistant lymphosarcoma RLS40 in vivo. The vaccines were the following: microvesicle vaccines—cytochalasin B-induced membrane vesicles (CIMVs) obtained from DCs loaded with total tumor RNA using cholesterol/spermine-containing cationic liposomes L or mannosylated liposomes ML; DC vaccines—murine DCs loaded with total tumor-derived RNA using the same liposomes; and liposomal vaccines—lipoplexes of total tumor-derived RNA with liposomes L or ML. Being non-hepatotoxic, CIMV- and DC-based vaccines administered subcutaneously exhibited comparable potential to stimulate highly efficient antitumor CTLs in vivo, whereas liposomal vaccines were 25% weaker CTL inducers. Nevertheless, the antitumor efficiencies of the different types of the vaccines were similar: sizes of tumor nodes and the number of liver metastases were significantly decreased, regardless of the vaccine type. Notably, the booster vaccination did not improve the overall antitumor efficacy of the vaccines under the study. CIMV- and DC- based vaccines more efficiently than liposome-based ones decreased mitotic activity of tumor cells and induced their apoptosis, stimulated accumulation of neutrophil inflammatory infiltration in tumor tissue, and had a more pronounced immunomodulatory activity toward the spleen and thymus. Administration of CIMV-, DC-, and liposome-based vaccines resulted in activation of Th1/Th17 cells as well as the induction of positive immune checkpoint 4-1BBL and downregulation of suppressive immune checkpoints in a raw PD-1 >>> TIGIT > CTLA4 > TIM3. We demonstrated that cell-free CIMV-based vaccines exhibited superior antitumor and antimetastatic activity in a tumor model in vivo. The obtained results can be considered as the basis for developing novel strategies for oncoimmunotherapy.

Methods of the Large-Scale Production of Extracellular Vesicles

To date, extracellular vesicles (EVs) have been extensively investigated as potential substitutes for cell therapy. Research has suggested their ability to overcome serious risks associated with the application of these cells. Although, the translation of EVs into clinical practice is hampered by the lack of a cheap reasonable way to obtain a clinically relevant number of EVs, an available method for the large-scale production of EVs ensures vesicles’ integrity, preserves their biological activity, and ensures they are well reproducible, providing homogeneity of the product from batch to batch. In this review, advances in the development of methods to increase EVs production are discussed. The existing approaches can be divided into the following: (1) those based on increasing the production of natural EVs by creating and using high capacity “cell factories”, (2) those based on the induction of EVs secretion under various cell stressors, and (3) those based on cell fragmentation with the creation of biomimetic vesicles. The aim of this review is to stimulate the introduction of EVs into clinical practice and to draw attention to the development of new methods of EVs production on a large scale.

Mesenchymal Stem Cell-Derived Extracellular Vesicles in Liver Immunity and Therapy

Mesenchymal stem cells (MSCs), as the most common cell source for stem cell therapy, play an important role in the modulation of innate and adaptive immune responses and have been widely used in clinical trials to treat autoimmune and inflammatory diseases. Recent experimental and clinical studies have shown that MSC-derived extracellular vesicles (MSC-EVs) can inhibit the activation and proliferation of a variety of proinflammatory cells, such as Th1, Th17 and M1 macrophages, reducing the secretion of proinflammatory cytokines, while promoting the proliferation of anti-inflammatory cells, such as M2 macrophages and Tregs, and increasing the secretion of anti-inflammatory cytokines, thus playing a role in immune regulation and exhibiting immunomodulatory functions. Besides MSC-EVs are more convenient and less immunogenic than MSCs. There is growing interest in the role of MSC-EVs in liver diseases owing to the intrinsic liver tropism of MSC-EVs. In this review, we focus on the immunomodulatory effects of MSC-EVs and summarize the pivotal roles of MSC-EVs as a cell-free therapy in liver diseases, including NAFLD, AIH, acute liver failure, liver fibrosis and hepatic ischemia–reperfusion injury. Moreover, we provide a concise overview of the potential use and limits of MSC-EVs in clinical application.

Mesenchymal Stem Cell Immunomodulation: A Novel Intervention Mechanism in Cardiovascular Disease

Mesenchymal stem cells (MSCs) are the member of multipotency stem cells, which possess the capacity for self-renewal and multi-directional differentiation, and have several characteristics, including multi-lineage differentiation potential and immune regulation, which make them a promising source for cell therapy in inflammation, immune diseases, and organ transplantation. In recent years, MSCs have been described as a novel therapeutic strategy for the treatment of cardiovascular diseases because they are potent modulators of immune system with the ability to modulating immune cell subsets, coordinating local and systemic innate and adaptive immune responses, thereby enabling the formation of a stable inflammatory microenvironment in damaged cardiac tissues. In this review, the immunoregulatory characteristics and potential mechanisms of MSCs are sorted out, the effect of these MSCs on immune cells is emphasized, and finally the application of this mechanism in the treatment of cardiovascular diseases is described to provide help for clinical application.

Immunogenic Properties of MVs Containing Structural Hantaviral Proteins: An Original Study

Hemorrhagic fever with renal syndrome (HFRS) is an emerging infectious disease that remains a global public health threat. The highest incidence rate is among zoonotic disease cases in Russia. Most cases of HFRS are reported in the Volga region of Russia, which commonly identifies the Puumala virus (PUUV) as a pathogen. HFRS management is especially challenging due to the lack of specific treatments and vaccines. This study aims to develop new approaches for HFRS prevention. Our goal is to test the efficacy of microvesicles (MVs) as PUUV nucleocapsid (N) and glycoproteins (Gn/Gc) delivery vehicles. Our findings show that MVs could deliver the PUUV N and Gn/Gc proteins in vitro. We have also demonstrated that MVs loaded with PUUV proteins could elicit a specific humoral and cellular immune response in vivo. These data suggest that an MV-based vaccine could control HFRS.

Extracellular Vesicles of Mesenchymal Stem Cells: Therapeutic Properties Discovered with Extraordinary Success

Mesenchymal stem cells (MSCs), the cells distributed in the stromas of the body, are known for various properties including replication, the potential of various differentiations, the immune-related processes including inflammation. About two decades ago, these cells were shown to play relevant roles in the therapy of numerous diseases, dependent on their immune regulation and their release of cytokines and growth factors, with ensuing activation of favorable enzymes and processes. Such discovery induced great increase of their investigation. Soon thereafter, however, it became clear that therapeutic actions of MSCs are risky, accompanied by serious drawbacks and defects. MSC therapy has been therefore reduced to a few diseases, replaced for the others by their extracellular vesicles, the MSC-EVs. The latter vesicles recapitulate most therapeutic actions of MSCs, with equal or even better efficacies and without the serious drawbacks of the parent cells. In addition, MSC-EVs are characterized by many advantages, among which are their heterogeneities dependent on the stromas of origin, the alleviation of cell aging, the regulation of immune responses and inflammation. Here we illustrate the MSC-EV therapeutic effects, largely mediated by specific miRNAs, covering various diseases and pathological processes occurring in the bones, heart and vessels, kidney, and brain. MSC-EVs operate also on the development of cancers and on COVID-19, where they alleviate the organ lesions induced by the virus. Therapy by MSC-EVs can be improved by combination of their innate potential to engineering processes inducing precise targeting and transfer of drugs. The unique properties of MSC-EVs explain their intense studies, carried out with extraordinary success. Although not yet developed to clinical practice, the perspectives for proximal future are encouraging.

A First Phenotypic and Functional Characterization of Placental Extracellular Vesicles from Women with Multiple Sclerosis

Pregnancy is a unique situation of physiological immunomodulation, as well as a strong Multiple Sclerosis (MS) disease modulator whose mechanisms are still unclear. Both maternal (decidua) and fetal (trophoblast) placental cells secrete extracellular vesicles (EVs), which are known to mediate cellular communication and modulate the maternal immune response. Their contribution to the MS disease course during pregnancy, however, is unexplored. Here, we provide a first phenotypic and functional characterization of EVs isolated from cultures of term placenta samples of women with MS, differentiating between decidua and trophoblast. In particular, we analyzed the expression profile of 37 surface proteins and tested the functional role of placental EVs on mono-cultures of CD14⁺ monocytes and co-cultures of CD4⁺ T and regulatory T (Treg) cells. Results indicated that placental EVs are enriched for surface markers typical of stem/progenitor cells, and that conditioning with EVs from samples of women with MS is associated to a moderate decrease in the expression of proinflammatory cytokines by activated monocytes and in the proliferation rate of activated T cells co-cultured with Tregs. Overall, our findings suggest an immunomodulatory potential of placental EVs from women with MS and set the stage for a promising research field aiming at elucidating their role in MS remission.

Cytochalasin B-Induced Membrane Vesicles from Human Mesenchymal Stem Cells Overexpressing IL2 Are Able to Stimulate CD8+ T-Killers to Kill Human Triple Negative Breast Cancer Cells

Simple Summary

Almost all human cells release extracellular vesicles participating in intercellular communication. Extracellular vesicles are rounded structures surrounded by the cytoplasmic membrane, which embody cytoplasmic contents of the parental cells, which makes extracellular vesicles a promising therapeutic tool for cell-free cancer therapy. In this study, human mesenchymal stem cells were genetically modified to overexpress human interleukin-2 (IL2), a cytokine which regulates the proliferation and activation of immune cells. Membrane vesicle release from native and genetically modified stem cells was induced by cytochalasin B treatment to increase the yield of membrane vesicles. To evaluate the immunomodulating properties of isolated membrane vesicles, immune cells were isolated from human peripheral blood and co-cultured with membrane vesicles from native or IL2 overexpressing stem cells. To analyze the anti-tumor activity of immune cells after interaction with IL2-enriched membrane vesicles, immune cells were co-cultured with triple negative breast cancer cells. As a result, IL2-enriched membrane vesicles were able to activate and stimulate the proliferation of immune cells, which in turn were able to induce apoptosis in breast cancer cells. Therefore, the production of IL2-enriched membrane vesicles represents a unique opportunity to meet the potential of extracellular vesicles to be used in clinical applications for cancer therapy.

Abstract

Interleukin 2 (IL2) was one of the first cytokines used for cancer treatment due to its ability to stimulate anti-cancer immunity. However, recombinant IL2-based therapy is associated with high systemic toxicity and activation of regulatory T-cells, which are associated with the pro-tumor immune response. One of the current trends for the delivery of anticancer agents is the use of extracellular vesicles (EVs), which can carry and transfer biologically active cargos into cells. The use of EVs can increase the efficacy of IL2-based anti-tumor therapy whilst reducing systemic toxicity. In this study, human adipose tissue-derived mesenchymal stem cells (hADSCs) were transduced with lentivirus encoding IL2 (hADSCs-IL2). Membrane vesicles were isolated from hADSCs-IL2 using cytochalasin B (CIMVs-IL2). The effect of hADSCs-IL2 and CIMVs-IL2 on the activation and proliferation of human peripheral blood mononuclear cells (PBMCs) as well as the cytotoxicity of activated PBMCs against human triple negative cancer MDA-MB-231 and MDA-MB-436 cells were evaluated. The effect of CIMVs-IL2 on murine PBMCs was also evaluated in vivo. CIMVs-IL2 failed to suppress the proliferation of human PBMCs as opposed to hADSCs-IL2. However, CIMVs-IL2 were able to activate human CD8⁺ T-killers, which in turn, killed MDA-MB-231 cells more effectively than hADSCs-IL2-activated CD8⁺ T-killers. This immunomodulating effect of CIMVs-IL2 appears specific to human CD8⁺ T-killer cells, as the same effect was not observed on murine CD8⁺ T-cells. In conclusion, the use of CIMVs-IL2 has the potential to provide a more effective anti-cancer therapy. This compelling evidence supports further studies to evaluate CIMVs-IL2 effectiveness, using cancer mouse models with a reconstituted human immune system.