The Effect of Mesenchymal Stem Cell-Derived Extracellular Vesicles on Hematopoietic Stem Cells Fate

Biology and Therapeutic Properties of Mesenchymal Stem Cells in Leukemia

This comprehensive review delves into the multifaceted roles of mesenchymal stem cells (MSCs) in leukemia, focusing on their interactions within the bone marrow microenvironment and their impact on leukemia pathogenesis, progression, and treatment resistance. MSCs, characterized by their ability to differentiate into various cell types and modulate the immune system, are integral to the BM niche, influencing hematopoietic stem cell maintenance and functionality. This review extensively explores the intricate relationship between MSCs and leukemic cells in acute myeloid leukemia, acute lymphoblastic leukemia, chronic myeloid leukemia, and chronic lymphocytic leukemia. This review also addresses the potential clinical applications of MSCs in leukemia treatment. MSCs' role in hematopoietic stem cell transplantation, their antitumor effects, and strategies to disrupt chemo-resistance are discussed. Despite their therapeutic potential, the dual nature of MSCs in promoting and inhibiting tumor growth poses significant challenges. Further research is needed to understand MSCs' biological mechanisms in hematologic malignancies and develop targeted therapeutic strategies. This in-depth exploration of MSCs in leukemia provides crucial insights for advancing treatment modalities and improving patient outcomes in hematologic malignancies.

Mesenchymal stromal cell-derived secretome-based therapy for neurodegenerative diseases: overview of clinical trials

BACKGROUND

Over the past few years, mesenchymal stromal cells (MSCs) have attracted a great deal of scientific attention owing to their promising results in the treatment of incurable diseases. However, there are several concerns about their possible side effects after direct cell transplantation, including host immune response, time-consuming cell culture procedures, and the dependence of cell quality on the donor, which limit the application of MSCs in clinical trials. On the other hand, it is well accepted that the beneficial effects of MSCs are mediated by secretome rather than cell replacement. MSC secretome refers to a variety of bioactive molecules involved in different biological processes, specifically neuro-regeneration.

MAIN BODY

Due to the limited ability of the central nervous system to compensate for neuronal loss and relieve disease progress, mesenchymal stem cell products may be used as a potential cure for central nervous system disorders. In the present study, the therapeutic effects of MSC secretome were reviewed and discussed the possible mechanisms in the three most prevalent central nervous system disorders, namely Alzheimer's disease, multiple sclerosis, and Parkinson's disease. The current work aimed to help discover new medicine for the mentioned complications.

CONCLUSION

The use of MSC-derived secretomes in the treatment of the mentioned diseases has encouraging results, so it can be considered as a treatment option for which no treatment has been introduced so far.

Bone marrow-derived extracellular vesicles carry the TGF-β signal transducer Smad2 to preserve hematopoietic stem cells in mice

Extracellular vesicles (EVs) released by cells in the bone marrow (BM) are important for regulating proliferation, differentiation, and other processes in hematopoietic stem cells (HSC). TGF-β signaling is now well known to be involved in HSC's quiescence and maintenance, but the TGF-β pathway related to EVs is still largely unknown in the hematopoietic system. We found that the EV inhibitor Calpeptin, when injected intravenously into mice, particularly affected the in vivo production of EVs carrying phosphorylated Smad2 (p-Smad2) in mouse BM. This was accompanied with an alteration in the quiescence and maintenance of murine HSC in vivo. EVs produced by murine mesenchymal stromal MS-5 cells also showed presence of p-Smad2 as a cargo. We treated MS-5 cells with the TGF-β inhibitor SB431542 in order to produce EVs lacking p-Smad2, and discovered that its presence was required for ex vivo maintenance of HSC. In conclusion, we revealed a new mechanism involving EVs produced in the mouse BM that transport bioactive phosphorylated Smad2 as a cargo to enhance the TGF-β signaling-mediated quiescence and maintenance of HSC.

Engineered Tissue Models to Replicate Dynamic Interactions within the Hematopoietic Stem Cell Niche

Hematopoietic stem cells are the progenitors of the blood and immune system and represent the most widely used regenerative therapy. However, their rarity and limited donor base necessitate the design of ex vivo systems that support HSC expansion without the loss of long-term stem cell activity. This review describes recent advances in biomaterials systems to replicate features of the hematopoietic niche. Inspired by the native bone marrow, these instructive biomaterials provide stimuli and cues from cocultured niche-associated cells to support HSC encapsulation and expansion. Engineered systems increasingly enable study of the dynamic nature of the matrix and biomolecular environment as well as the role of cell-cell signaling (e.g., autocrine feedback vs paracrine signaling between dissimilar cells). The inherent coupling of material properties, biotransport of cell-secreted factors, and cell-mediated remodeling motivate dynamic biomaterial systems as well as characterization and modeling tools capable of evaluating a temporally evolving tissue microenvironment. Recent advances in HSC identification and tracking, model-based experimental design, and single-cell culture platforms facilitate the study of the effect of constellations of matrix, cell, and soluble factor signals on HSC fate. While inspired by the HSC niche, these tools are amenable to the broader stem cell engineering community.

Anti-inflammatory and M2 macrophage polarization-promoting effect of mesenchymal stem cell-derived exosomes

Mesenchymal stem cells (MSCs) are multipotent cells beneficial in regenerative medicine and tissue repair. The therapeutic potential of MSCs for inflammatory diseases and conditions is partly due to secreted exosomes. Exosomes are one group of extracellular vesicles with 50-150 nm in diameter. They can carry numerous molecules and introduce them to the recipient cells to produce various biological effects. Macrophages are classified into M1 and M2 subtypes based on their activation states. M1 macrophages release pro-inflammatory factors like tumor necrosis factoralfa (TNF-α), interleukin1alfa (IL-1α), interleukin1beta (IL-1β), interleukin6 (IL-6), C-X-C motif chemokine ligand 9 (CXCL9), and C-X-C motif chemokine ligand 10 (CXCL10), while M2 macrophages secrete anti-inflammatory mediators including interleukin10 (IL-10), transforming growth factor beta (TGF-β), C-C motif chemokine ligand 1 (CCL1), C-C motif chemokine ligand 17 (CCL17), C-C motif chemokine ligand 18 (CCL18), and C-C motif chemokine ligand 22 (CCL22). This review summarizes the effect of MSC-derived exosomes in the polarization of M2 macrophages, which their anti-inflammatory and immunomodulatory properties are potentially effective in inflammation diseases and conditions such as central nervous system (CNS) diseases, autoimmune diseases, inflammatory bowel disease, cardiomyopathy, graftversushost disease, kidney, liver, lung, and skin injuries.

Improving hematopoietic engraftment: Potential role of mesenchymal stromal cell-derived extracellular vesicles

The therapeutic effects of mesenchymal stromal cells (MSCs) in graft failure or poor graft function after allogenic hematopoietic stem cell transplantation (HSCT) are currently undergoing clinical evaluation. MSCs exert their functions, at least partially, through the secretion of extracellular vesicles (MSC-EVs). The available information on the biological potential of MSC-EVs to improve hematopoietic function, both in in vitro studies and in reported preclinical models, focusing on the possible mechanisms of these effects are summarized in the current review. The potential advantages of EVs over MSCs are also discussed, as well as the limitations and uncertainties in terms of isolation, characterization, mechanism of action in this setting, and industrial scalability that should be addressed for their potential clinical application.

DNA damage repair response in mesenchymal stromal cells: From cellular senescence and aging to apoptosis and differentiation ability

Mesenchymal stromal cells (MSCs) are heterogeneous and contain several populations, including stem cells. MSCs' secretome has the ability to induce proliferation, differentiation, chemo-attraction, anti-apoptosis, and immunomodulation activities in stem cells. Moreover, these cells recognize tissue damage caused by drugs, radiation (e.g., Ultraviolet, infra-red) and oxidative stress, and respond in two ways: either MSCs differentiate into particular cell lineages to preserve tissue homeostasis, or they release a regenerative secretome to activate tissue repairing mechanisms. The maintenance of MSCs in quiescence can increase the incidence and accumulation of various forms of genomic modifications, particularly upon environmental insults. Thus, dysregulated DNA repair pathways can predispose MSCs to senescence or apoptosis, reducing their stemness and self-renewal properties. For instance, DNA damage can impair telomere replication, activating DNA damage checkpoints to maintain MSC function. In this review, we aim to summarize the role of DNA damage and associated repair responses in MSC senescence, differentiation and programmed cell death.

Extracellular Vesicles After Allogeneic Hematopoietic Cell Transplantation: Emerging Role in Post-Transplant Complications

Extracellular vesicles (EVs) play an important role in the cellular crosstalk by transferring bioactive molecules through biological barriers from a cell to another, thus influencing recipient cell functions and phenotype. Therefore, EVs are increasingly being explored as biomarkers of disease progression or response to therapy and as potential therapeutic agents in different contexts including in hematological malignancies. Recently, an EV role has emerged in allogeneic hematopoietic cell transplantation (allo-HCT) as well. Allogeneic hematopoietic cell transplantation often represents the only curative option in several hematological disorders, but it is associated with potentially life-threatening complications that can have a significant impact on clinical outcomes. The most common complications have been well-established and include graft-versus-host disease and infections. Furthermore, relapse remains an important cause of treatment failure. The aim of this review is to summarize the current knowledge, the potential applications, and clinical relevance of EVs in allo-HCT. Herein, we will mainly focus on the immune-modulating properties of EVs, in particular those derived from mesenchymal stromal cells, as potential therapeutic strategy to improve allo-HCT outcome. Moreover, we will briefly describe the main findings on EVs as biomarkers to monitor graft-versus-host disease onset and tumor relapse.

The Role of Bone Marrow Mesenchymal Stem Cell Derived Extracellular Vesicles (MSC-EVs) in Normal and Abnormal Hematopoiesis and Their Therapeutic Potential

Mesenchymal stem cells (MSCs) represent a heterogeneous cellular population responsible for the support, maintenance, and regulation of normal hematopoietic stem cells (HSCs). In many hematological malignancies, however, MSCs are deregulated and may create an inhibitory microenvironment able to induce the disease initiation and/or progression. MSCs secrete soluble factors including extracellular vesicles (EVs), which may influence the bone marrow (BM) microenvironment via paracrine mechanisms. MSC-derived EVs (MSC-EVs) may even mimic the effects of MSCs from which they originate. Therefore, MSC-EVs contribute to the BM homeostasis but may also display multiple roles in the induction and maintenance of abnormal hematopoiesis. Compared to MSCs, MSC-EVs have been considered a more promising tool for therapeutic purposes including the prevention and treatment of Graft Versus Host Disease (GVHD) following allogenic HSC transplantation (HSCT). There are, however, still unanswered questions such as the molecular and cellular mechanisms associated with the supportive effect of MSC-EVs, the impact of the isolation, purification, large-scale production, storage conditions, MSC source, and donor characteristics on MSC-EV biological effects as well as the optimal dose and safety for clinical usage. This review summarizes the role of MSC-EVs in normal and malignant hematopoiesis and their potential contribution in treating GVHD.

Perspectives for Future Use of Extracellular Vesicles from Umbilical Cord- and Adipose Tissue-Derived Mesenchymal Stem/Stromal Cells in Regenerative Therapies-Synthetic Review

Mesenchymal stem/ stromal cells (MSCs) represent progenitor cells of various origin with multiple differentiation potential, representing the most studied population of stem cells in both in vivo pre-clinical and clinical studies. MSCs may be found in many tissue sources including extensively studied adipose tissue (ADSCs) and umbilical cord Wharton’s jelly (UC-MSCs). Most of sanative effects of MSCs are due to their paracrine activity, which includes also release of extracellular vesicles (EVs). EVs are small, round cellular derivatives carrying lipids, proteins, and nucleic acids including various classes of RNAs. Due to several advantages of EVs when compare to their parental cells, MSC-derived EVs are currently drawing attention of several laboratories as potential new tools in tissue repair. This review focuses on pro-regenerative properties of EVs derived from ADSCs and UC-MSCs. We provide a synthetic summary of research conducted in vitro and in vivo by employing animal models and within initial clinical trials focusing on neurological, cardiovascular, liver, kidney, and skin diseases. The summarized studies provide encouraging evidence about MSC-EVs pro-regenerative capacity in various models of diseases, mediated by several mechanisms. Although, direct molecular mechanisms of MSC-EV action are still under investigation, the current growing data strongly indicates their potential future usefulness for tissue repair.

The Incorporation of Extracellular Vesicles from Mesenchymal Stromal Cells Into CD34+ Cells Increases Their Clonogenic Capacity and Bone Marrow Lodging Ability

Mesenchymal stromal cells (MSC) may exert their functions by the release of extracellular vesicles (EV). Our aim was to analyze changes induced in CD34⁺ cells after the incorporation of MSC‐EV. MSC‐EV were characterized by flow cytometry (FC), Western blot, electron microscopy, and nanoparticle tracking analysis. EV incorporation into CD34⁺ cells was confirmed by FC and confocal microscopy, and then reverse transcription polymerase chain reaction and arrays were performed in modified CD34⁺ cells. Apoptosis and cell cycle were also evaluated by FC, phosphorylation of signal activator of transcription 5 (STAT5) by WES Simple, and clonal growth by clonogenic assays. Human engraftment was analyzed 4 weeks after CD34⁺ cell transplantation in nonobese diabetic/severe combined immunodeficient mice. Our results showed that MSC‐EV incorporation induced a downregulation of proapoptotic genes, an overexpression of genes involved in colony formation, and an activation of the Janus kinase (JAK)‐STAT pathway in CD34⁺ cells. A significant decrease in apoptosis and an increased CD44 expression were confirmed by FC, and increased levels of phospho‐STAT5 were confirmed by WES Simple in CD34⁺ cells with MSC‐EV. In addition, these cells displayed a higher colony‐forming unit granulocyte/macrophage clonogenic potential. Finally, the in vivo bone marrow lodging ability of human CD34⁺ cells with MSC‐EV was significantly increased in the injected femurs. In summary, the incorporation of MSC‐EV induces genomic and functional changes in CD34⁺ cells, increasing their clonogenic capacity and their bone marrow lodging ability. stem cells2019;37:1357–1368

Chimeric feeders of mesenchymal stromal cells and stromal cells modified with constitutively active AKT expand hematopoietic stem cells

Aim: To examine whether AKT-modified stromal cells expand human CD34⁺ hematopoietic stem cells (HSCs). Methods: Coculture, in vitro functional assays, immuno-fluorescence microscopy, flow cytometry. Results: M2-10B4 stromal cells (M2) modified with AKT1 (M2-AKT) expanded primitive CD34⁺38^- HSCs, but affected their functionality. A chimeric feeder layer comprising naive human bone marrow-derived mesenchymal stromal cells and M2-AKT not only overcame the negative effects of M2-AKT, but, unexpectedly, also gave a synergistic effect on the growth and functionality of the HSCs. Conditioned medium of bone marrow stromal cells worked as effectively, but cell-cell contact between HSCs and M2-AKT cells was necessary for the synergistic effect of M2-AKT and bone marrow-derived mesenchymal stromal cells or their CM. Conclusion: Chimeric feeders expand HSCs.