Extracellular vesicles derived from mesenchymal stem cells (MSC-EVs) have been widely reported as promising cell-free products that show therapeutic effects of the parental cells but not their limitations. Due to the intrinsic liver tropism of MSC-EVs, they have been widely used as therapeutics or drug carriers for treatment of liver diseases. However, rapid clearance from the target site may attenuate the efficiency of systemically administered MSC-EVs. Herein, sustained release into the peritoneum has been proposed as a new strategy to prolong the bioavailability of the MSC-EVs in the target liver. During intraperitoneal injection, clickable polyethylene glycol (PEG) macromeres were mixed with MSC-EVs to form EV-encapsulated PEG hydrogels via a fast, biocompatible click reaction. Upon biodegradation, the EV-laden hydrogels were swollen gradually to release EVs in a sustained manner over 1 month. In vivo tracking of the labeled EVs revealed that the accumulation of EVs in the liver was extended by hydrogel-mediated delivery for 1 month. Four weeks after injection in a rat model of chronic liver fibrosis, the physical and histopathological investigations of the harvested liver showed superior antifibrosis, anti-apoptosis, and regenerative effects of the EVs when delivered by the sustained systemic release (Gel-EV) to the conventional bolus injection (Free-EV). Specifically, the Gel-EV system improved the antifibrosis, anti-inflammation, anti-apoptosis, and regenerative effects of the EVs to nearly 40, 50, 40, and 50% compared to Free-EV, respectively, as was specified by quantification of the fibrotic area, α-SMA density, and caspase-3 density in the harvested tissues and ALT enzyme in serum. This study may potentiate the use of MSC-EVs as cell-free therapeutics for chronic liver failure. The sustained systemic delivery strategy may open a new paradigm to extend the effects of disease-targeting EVs over time.

Various somatic tissue-derived mesenchymal stromal cells (MSCs) have been considered as an attractive therapeutic tool for treatment of liver diseases in which the secretion of soluble factors or extracellular vesicles (EVs) is the most probable mechanism. The experimental application of human embryonic stem cell-derived MSC (ES-MSC) increased rapidly and showed promising results, in vitro and in vivo. However, possible therapeutic effects of human ES-MSC and their EVs on Thioacetamide (TAA)-induced chronic liver injury have not been evaluated yet. Our data indicated that human ES-MSC can significantly suppress the proliferation of peripheral blood mononuclear cells compared to bone marrow (BM)-MSC and adipose (AD)-MSC. Moreover, ES-MSC increased the secretion of anti-inflammatory cytokines (i.e., TGF-β and IL-10) and decreased IFN-γ, compared to other MSCs. ES-MSC EVs demonstrated immunomodulatory activities comparable to parental cells and ameliorated cirrhosis in TAA-induced chronic rat liver injury, that is, reduction in fibrosis and collagen density, necrosis, caspase density, portal vein diameter, and transaminitis. The gene expression analyses also showed upregulation in collagenases (MMP9 and MMP13), anti-apoptotic gene (BCL-2) and anti-inflammatory cytokines (TGF-β1 and IL-10) and down-regulation of major contributors to fibrosis (Col1α, αSMA, and TIMP1), pro-apoptotic gene (BAX) and pro-inflammatory cytokines (TNFα and IL-2) following treatment with ES-MSC and ES-MSC-EV. These results demonstrated that human ES-MSC and ES-MSC EV as an off-the-shelf product, that needs further assessment to be suggested as an allogeneic product for therapeutic applications for liver fibrosis.

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Mesenchymal stromal cells (MSCs) can effectively contribute to tissue regeneration inside the inflammatory microenvironment mostly through modulating immune responses. MSC‐derived extracellular vesicles (MSC‐EVs) display immunoregulatory functions similar to parent cells. Interactions between MSC‐EVs and immune cells make them an ideal therapeutic candidate for infectious, inflammatory, and autoimmune diseases. These properties of MSC‐EVs have encouraged researchers to perform extensive studies on multiple factors that mediate MSC‐EVs immunomodulatory effects. Investigation of proteins involved in the complex interplay of MSC‐EVs and immune cells may help us to better understand their functions. Here, we performed a comprehensive proteomic analysis of MSC‐EVs that was previously reported by ExoCarta database. A total of 938 proteins were identified as MSC‐EV proteome using quantitative proteomics techniques. Kyoto Encyclopedia of Genes and Genomes analysis demonstrates that ECM–receptor interaction, focal adhesion, and disease‐specific pathways are enriched in MSC‐EVs. By detail analysis of proteins presence in immune system process, we found that expression of some cytokines, chemokines, and chemokine receptors such as IL10, HGF, LIF, CCL2, VEGFC, and CCL20, which leads to migration of MSC‐EVs to injured sites, suppression of inflammation and promotion of regeneration in inflammatory and autoimmune diseases. Also, some chemoattractant proteins such as CXCL2, CXCL8, CXCL16, DEFA1, HERC5, and IFITM2 were found in MSC‐EV proteome. They may actively recruit immune cells to the proximity of MSC or MSC‐EVs, may result in boosting immune response under specific circumstances, and may have protective role in infectious diseases. In this review, we summarize available information about immunomodulation of MSC‐EVs with particular emphasis on their proteomics analysis.

Mesenchymal stem cells (MSCs) are adult multipotent cells that due to their ability to homing to damaged tissues and differentiate into specialized cells, are remarkable cells in the field of regenerative medicine. It's suggested that the predominant mechanism of MSCs in tissue repair might be related to their paracrine activity. The utilization of MSCs for tissue repair is initially based on the differentiation ability of these cells; however now it has been revealed that only a small fraction of the transplanted MSCs actually fuse and survive in host tissues. Indeed, MSCs supply the microenvironment with the secretion of soluble trophic factors, survival signals and the release of extracellular vesicles (EVs) such as exosome. Also, the paracrine activity of EVs could mediate the cellular communication to induce cell-differentiation/self-renewal. Recent findings suggest that EVs released by MSCs may also be critical in the physiological function of these cells. This review provides an overview of MSC-derived extracellular vesicles as a hopeful opportunity to advance novel cell-free therapy strategies that might prevail over the obstacles and risks associated with the use of native or engineered stem cells. EVs are very stable; they can pass the biological barriers without rejection and can shuttle bioactive molecules from one cell to another, causing the exchange of genetic information and reprogramming of the recipient cells. Moreover, extracellular vesicles may provide therapeutic cargo for a wide range of diseases and cancer therapy.

Exosomes are nano vesicles from the larger family named Extracellular Vesicle (EV)s which are released by various cells including tumor cells, mast cells, dendritic cells, B lymphocytes, neurons, adipocytes, endothelial cells, and epithelial cells. They are considerable messengers that can exchange proteins and genetic materials between the cells. Within the past decade, Tumor derived exosomes (TEX) have been emerged as important mediators in cancer initiation, progression and metastasis as well as host immune suppression and drug resistance. Although tumor derived exosomes consist of tumor antigens and several Heat Shock Proteins such as HSP70 and HSP90 to stimulate immune response against tumor cells, they contain inhibitory molecules like Fas ligand (Fas-L), Transforming Growth Factor Beta (TGF-β) and Prostaglandin E2 (PGE2) leading to decrease the cytotoxicity and establish immunosuppressive tumor microenvironment (TME). To bypass this problem and enhance immune response, some macromolecules such as miRNAs, HSPs and activatory ligands have been recognized as potent immune inducers that could be used as anti-tumor agents to construct a nano sized tumor vaccine. Here, we discussed emerging engineered exosomes as a novel therapeutic strategy and considered the associated challenges.

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Organoids can be regarded as a beneficial tool for discovery of new therapeutics for diabetes and/or maturation of pancreatic progenitors (PP) towards β cells. Here, we devised a strategy to enhance maturation of PP by assembly of three‐dimensional (3D) pancreatic organoids (PO) containing human embryonic stem (ES) cell derivatives including ES‐derived pancreatic duodenal homeobox 1 (PDX1) + early PP, mesenchymal stem cells, and endothelial cells at an optimized cell ratio, on Matrigel. The PO was placed in a 3D‐printed tissue trapper and heterotopically implanted into the peritoneal cavity of immunodeficient mice where it remained for 90 days. Our results indicated that, in contrast to corresponding early PP transplants, 3D PO developed more vascularization as indicated by greater area and number of vessels, a higher number of insulin‐positive cells and improvement of human C‐peptide secretions. Based on our findings, PO‐derived β cells could be considered a novel strategy to study human β‐cell development, novel therapeutics, and regenerative medicine for diabetes.