Mesenchymal Stem Cell-derived Extracellular Vesicles Research Articles

Delivery of miR-15b-5p via magnetic nanoparticle-enhanced bone marrow mesenchymal stem cell-derived extracellular vesicles mitigates diabetic osteoporosis by targeting GFAP

Diabetic osteoporosis (DO) presents significant clinical challenges. This study aimed to investigate the potential of magnetic nanoparticle-enhanced extracellular vesicles (GMNPE-EVs) derived from bone marrow mesenchymal stem cells (BMSCs) to deliver miR-15b-5p, thereby targeting and downregulating glial fibrillary acidic protein (GFAP) expression in rat DO models. Data was sourced from DO-related RNA-seq datasets combined with GEO and GeneCards databases. Rat primary BMSCs, bone marrow-derived macrophages (BMMs), and osteoclasts were isolated and cultured. EVs were separated, and GMNPE targeting EVs were synthesized. Bioinformatic analysis revealed a high GFAP expression in DO-related RNA-seq and GSE26168 datasets for disease models. Experimental results confirmed elevated GFAP in rat DO bone tissues, promoting osteoclast differentiation. miR-15b-5p was identified as a GFAP inhibitor, but was significantly downregulated in DO and enriched in BMSC-derived EVs. In vitro experiments showed that GMNPE-EVs could transfer miR-15b-5p to osteoclasts, downregulating GFAP and inhibiting osteoclast differentiation. In vivo tests confirmed the therapeutic potential of this approach in alleviating rat DO. Collectively, GMNPE-EVs can effectively deliver miR-15b-5p to osteoclasts, downregulating GFAP expression, and hence, offering a therapeutic strategy for rat DO.

Extracellular Vesicles: The Next Generation of Biomarkers and Treatment for Central Nervous System Diseases.

It has been widely established that the characterization of extracellular vesicles (EVs), particularly small EVs (sEVs), shed by different cell types into biofluids, helps to identify biomarkers and therapeutic targets in neurological and neurodegenerative diseases. Recent studies are also exploring the efficacy of mesenchymal stem cell-derived extracellular vesicles naturally enriched with therapeutic microRNAs and proteins for treating various diseases. In addition, EVs released by various neural cells play a crucial function in the modulation of signal transmission in the brain in physiological conditions. However, in pathological conditions, such EVs can facilitate the spread of pathological proteins from one brain region to the other. On the other hand, the analysis of EVs in biofluids can identify sensitive biomarkers for diagnosis, prognosis, and disease progression. This review discusses the potential therapeutic use of stem cell-derived EVs in several central nervous system diseases. It lists their differences and similarities and confers various studies exploring EVs as biomarkers. Further advances in EV research in the coming years will likely lead to the routine use of EVs in therapeutic settings.

CORR Insights®: Human Infrapatellar Fat Pad Mesenchymal Stem Cell-derived Extracellular Vesicles Purified by Anion Exchange Chromatography Suppress Osteoarthritis Progression in a Mouse Model.

CORR Insights®: Human Infrapatellar Fat Pad Mesenchymal Stem Cell-derived Extracellular Vesicles Purified by Anion Exchange Chromatography Suppress Osteoarthritis Progression in a Mouse Model.

The emerging role of mesenchymal stem cell-derived extracellular vesicles to ameliorate hippocampal NLRP3 inflammation induced by binge-like ethanol treatment in adolescence.

JOURNAL/nrgr/04.03/01300535-202504000-00030/figure1/v/2024-07-06T104127Z/r/image-tiff Our previous studies have reported that activation of the NLRP3 (NOD-, LRR- and pyrin domain-containing protein 3)-inflammasome complex in ethanol-treated astrocytes and chronic alcohol-fed mice could be associated with neuroinflammation and brain damage. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have been shown to restore the neuroinflammatory response, along with myelin and synaptic structural alterations in the prefrontal cortex, and alleviate cognitive and memory dysfunctions induced by binge-like ethanol treatment in adolescent mice. Considering the therapeutic role of the molecules contained in mesenchymal stem cell-derived extracellular vesicles, the present study analyzed whether the administration of mesenchymal stem cell-derived extracellular vesicles isolated from adipose tissue, which inhibited the activation of the NLRP3 inflammasome, was capable of reducing hippocampal neuroinflammation in adolescent mice treated with binge drinking. We demonstrated that the administration of mesenchymal stem cell-derived extracellular vesicles ameliorated the activation of the hippocampal NLRP3 inflammasome complex and other NLRs inflammasomes (e.g., pyrin domain-containing 1, caspase recruitment domain-containing 4, and absent in melanoma 2, as well as the alterations in inflammatory genes (interleukin-1β, interleukin-18, inducible nitric oxide synthase, nuclear factor-kappa B, monocyte chemoattractant protein-1, and C-X3-C motif chemokine ligand 1) and miRNAs (miR-21a-5p, miR-146a-5p, and miR-141-5p) induced by binge-like ethanol treatment in adolescent mice. Bioinformatic analysis further revealed the involvement of miR-21a-5p and miR-146a-5p with inflammatory target genes and NOD-like receptor signaling pathways. Taken together, these findings provide novel evidence of the therapeutic potential of MSC-derived EVs to ameliorate the hippocampal neuroinflammatory response associated with NLRP3 inflammasome activation induced by binge drinking in adolescence.

Bioregenerative Applications of the Human Mesenchymal Stem Cell- Derived Secretome: Part-I

Mesenchymal stem cells hold many therapeutic benefits in treating diverse disease states, but autologous requirements, high costs, lack of standardization and other factors limit their widespread application. Additionally, researchers have discovered that many mesenchymal stem cell in-vivo benefits originate from their paracrine factors. Therefore, cell-free therapeutics, including mesenchymal stem cell-derived conditioned medium and extracellular vesicles have been suggested as alternative bioregenerative therapies. This literature review summarizes mesenchymal stem cell application, the benefits of cell-free strategies and the components of its secretome. This manuscript is a companion piece to “Part 2: Bioregenerative Applications of the Human Mesenchymal Stem Cell-Derived Secretome,” included in this issue, which contains the results of in-vivo studies applying the conditioned medium and extracellular vesicles to human and animal models, ongoing clinical trials, limitations to cell-free strategies and future directions for the wide-scale adoption of these therapies.

Therapeutic Effects of Mesenchymal Stem Cell-Derived Extracellular Vesicles in sepsis: a Systematic Review and Meta-Analysis of Preclinical Studies.

Sepsis is a life-threatening disorder with no definitive cure. Preclinical studies suggest that extracellular vesicles derived from mesenchymal stromal cells (EV-MSCs) can mitigate inflammatory conditions, potentially leading to increased survival and reduced organ dysfunction during sepsis. Our aim to conduct this systematic review and meta-analysis is assessing the EV-MSCs therapeutic efficacy in sepsis. PubMed, Embase, Scopus, WOS and ProQuest databases and also Google Scholar search engine were searched for published articles. We used hazard ratio (HR) and standardized mean difference (SMD) as effect sizes to evaluate the therapeutic effect of EV-MSCs on survival rate and determine their effect on reducing organ dysfunction, respectively. Finally, we employed GRADE tool for preclinical animal studies to evaluate certainty of the evidence. 30 studies met the inclusion criteria for our article. Our meta-analysis results demonstrate that animals treated with MSC-EVs have better survival rate than untreated animals (HR = 0.33; 95% CI: 0.27-0.41). Our meta-analysis suggests that EV-MSCs can reduce organ dysfunctions in sepsis, such as the lung, kidney, and liver. Additionally, EV-MSCs decrease pro-inflammatory mediators like TNF-α, IL-1β, and IL-6. Our results indicate that EV-MSCs can be as promising therapy for sepsis management in animal models and leading to increased survival rate and reduced organ dysfunction. Furthermore, our study introduces a novel tool for risk of bias assessment and provides recommendations based on various analysis. Future studies with aiming to guide clinical translation can utilize the results of this article to establish stronger evidence for EV-MSC effectiveness.

#407 Human platelet lysate enhanced angiogenic potential of extracellular vesicles derived from mesenchymal stem cells

Abstract Background and Aims Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have emerged as a promising regenerative therapy. However, their clinical application is hampered by the presence of xenogeneic components in the medium. In the present study, we aimed to decipher the regenerative properties of MSC-EVs generated under xeno-free conditions to favor the clinical translation of MSC-EVs. Method MSCs were isolated from human umbilical cord and expanded in fetal bovine serum (FBS) and clinical-grade human platelet lysate (HPL) respectively. MSC-EVs were isolated by differential centrifugation combined with size exclusion chromatography and characterized through transmission electron microscopy, nanoparticle tracking analysis, and exoview. Subsequently, a multi-omics approach, comprising transcriptomics, proteomics, and metabolomics, was employed to investigate the molecular cargo of the MSC-EVs. Finally, in vitro and in vivo functional assays were performed to assess the regenerative potential of MSC-EVs in acute kidney injury. Results Our study demonstrated that HPL promoted MSC-EVs production without compromising EVs characteristics. Multi-omics sequencing revealed the stability of HPL cultured MSC-EVs (H-EVs) from different umbilical cord donors and global functional alterations for MSC-EVs under different culture conditions. In comparison to FBS cultured MSC-EVs (F-EVs), the regenerative potential of H-EVs was enhanced especially angiogenesis associated with increased cargo expression. The in vitro studies demonstrated that H-EVs induced more tube-like structure formation and migration. Further, it significantly reduced kidney capillary sparsity in mice with renal ischemic-reperfusion model. Conclusion Our data provided a comprehensive understanding about H-EVs and demonstrated their potential as a safe and effective regenerative therapy, especially targeting angiogenesis-related disorders.

Enhanced immunosuppressive capability of mesenchymal stem cell-derived small extracellular vesicles with high expression of CD73 in experimental autoimmune uveitis

BackgroundAutoimmune uveitis is an inflammatory disease triggered by an aberrant immune response. Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) are emerging as potential therapeutic agents for this condition. CD73, an ectoenzyme present on MSC-sEVs, is involved in mitigating inflammation by converting extracellular adenosine monophosphate into adenosine. We hypothesize that the inhibitory effect of MSC-sEVs on experimental autoimmune uveitis (EAU) could be partially attributed to the surface expression of CD73.MethodsTo investigate novel therapeutic approaches for autoimmune uveitis, we performed lentiviral transduction to overexpress CD73 on the surface of MSC-sEVs, yielding CD73-enriched MSC-sEVs (sEVs-CD73). Mice with interphotoreceptor retinoid-binding protein (IRBP)-induced EAU were grouped randomly and treated with 50 µg MSC-sEVs, vector infected MSC-sEVs, sEVs-CD73 or PBS via single tail vein injection. We evaluated the clinical and histological features of the induced mice and analyzed the proportion and functional capabilities of T helper cells. Furthermore, T-cells were co-cultured with various MSC-sEVs in vitro, and we quantified the resulting inflammatory response to assess the potential therapeutic benefits of sEVs-CD73.ResultsCompared to MSC-sEVs, sEVs-CD73 significantly alleviates EAU, leading to reduced inflammation and diminished tissue damage. Treatment with sEVs-CD73 results in a decreased proportion of Th1 cells in the spleen, draining lymph nodes, and eyes, accompanied by an increased proportion of regulatory T-cells (Treg cells). In vitro assays further reveal that sEVs-CD73 inhibits T-cell proliferation, suppresses Th1 cells differentiation, and enhances Treg cells proportion.ConclusionOver-expression of CD73 on MSC-sEVs enhances their immunosuppressive effects in EAU, indicating that sEVs-CD73 has the potential as an efficient immunotherapeutic agent for autoimmune uveitis.

MiR-4465-modified mesenchymal stem cell-derived small extracellular vesicles inhibit liver fibrosis development via targeting LOXL2 expression.

Liver fibrosis is a significant health burden, marked by the consistent deposition of collagen. Unfortunately, the currently available treatment approaches for this condition are far from optimal. Lysyl oxidase-like protein 2 (LOXL2) secreted by hepatic stellate cells (HSCs) is a crucial player in the cross-linking of matrix collagen and is a significant target for treating liver fibrosis. Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) have been proposed as a potential treatment option for chronic liver disorders. Previous studies have found that MSC-sEV can be used for microRNA delivery into target cells or tissues. It is currently unclear whether microRNA-4465 (miR-4465) can target LOXL2 and inhibit HSC activation. Additionally, it is uncertain whether MSC-sEV can be utilized as a gene therapy vector to carry miR-4465 and effectively inhibit the progression of liver fibrosis. This study explored the effect of miR-4465-modified MSC-sEV (MSC-sEVmiR-4465) on LOXL2 expression and liver fibrosis development. The results showed that miR-4465 can bind specifically to the promoter of the LOXL2 gene in HSC. Moreover, MSC-sEVmiR-4465 inhibited HSC activation and collagen expression by downregulating LOXL2 expression in vitro. MSC-sEVmiR-4465 injection could reduce HSC activation and collagen deposition in the CCl4-induced mouse model. MSC-sEVmiR-4465 mediating via LOXL2 also hindered the migration and invasion of HepG2 cells. In conclusion, we found that MSC-sEV can deliver miR-4465 into HSC to alleviate liver fibrosis via altering LOXL2, which might provide a promising therapeutic strategy for liver diseases.

HTERT-Immortalized Mesenchymal Stem Cell-Derived Extracellular Vesicles: Large-Scale Manufacturing, Cargo Profiling, and Functional Effects in Retinal Epithelial Cells.

As the economic burden associated with vision loss and ocular damage continues to rise, there is a need to explore novel treatment strategies. Extracellular vesicles (EVs) are enriched with various biological cargo, and there is abundant literature supporting the reparative and immunomodulatory properties of stem cell EVs across a broad range of pathologies. However, one area that requires further attention is the reparative effects of stem cell EVs in the context of ocular damage. Additionally, most of the literature focuses on EVs isolated from primary stem cells; the use of EVs isolated from human telomerase reverse transcriptase (hTERT)-immortalized stem cells has not been thoroughly examined. Using our large-scale EV-manufacturing platform, we reproducibly manufactured EVs from hTERT-immortalized mesenchymal stem cells (MSCs) and employed various methods to characterize and profile their associated cargo. We also utilized well-established cell-based assays to compare the effects of these EVs on both healthy and damaged retinal pigment epithelial cells. To the best of our knowledge, this is the first study to establish proof of concept for reproducible, large-scale manufacturing of hTERT-immortalized MSC EVs and to investigate their potential reparative properties against damaged retinal cells. The results from our studies confirm that hTERT-immortalized MSC EVs exert reparative effects in vitro that are similar to those observed in primary MSC EVs. Therefore, hTERT-immortalized MSCs may represent a more consistent and reproducible platform than primary MSCs for generating EVs with therapeutic potential.

Proteomic Analysis of Umbilical Cord Mesenchymal Stem Cell-Derived Extracellular Vesicles: A Systematic Review.

Numerous challenges remain within conventional cell-based therapy despite the growing trend of stem cells used to treat various life-debilitating diseases. These limitations include batch-to-batch heterogeneity, induced alloreactivity, cell survival and integration, poor scalability, and high cost of treatment, thus hindering successful translation from lab to bedside. However, recent pioneering technology has enabled the isolation and enrichment of small extracellular vesicles (EVs), canonically known as exosomes. EVs are described as a membrane-enclosed cargo of functional biomolecules not limited to lipids, nucleic acid, and proteins. Interestingly, studies have correlated the biological role of MSC-EVs to the paracrine activity of MSCs. This key evidence has led to rigorous studies on MSC-EVs as an acellular alternative. Using EVs as a therapy was proposed as a model leading to improvements through increased safety; enhanced bioavailability due to size and permeability; reduced heterogeneity by selective and quantifiable properties; and prolonged shelf-life via long-term freezing or lyophilization. Yet, the identity and potency of EVs are still relatively unknown due to various methods of preparation and to qualify the final product. This is reflected by the absence of regulatory strategies overseeing manufacturing, quality control, clinical implementation, and product registration. In this review, the authors review the various production processes and the proteomic profile of MSC-EVs.

Synergistic effect of mesenchymal stem cell-derived extracellular vesicle and miR-137 alleviates autism-like behaviors by modulating the NF-κB pathway

Autism spectrum disorder (ASD) is a multifaceted neurodevelopmental disorder predominant in childhood. Despite existing treatments, the benefits are still limited. This study explored the effectiveness of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) loaded with miR-137 in enhancing autism-like behaviors and mitigating neuroinflammation. Utilizing BTBR mice as an autism model, the study demonstrated that intranasal administration of MSC-miR137-EVs ameliorates autism-like behaviors and inhibits pro-inflammatory factors via the TLR4/NF-κB pathway. In vitro evaluation of LPS-activated BV2 cells revealed that MSC-miR137-EVs target the TLR4/NF-κB pathway through miR-137 inhibits proinflammatory M1 microglia. Moreover, bioinformatics analysis identified that MSC-EVs are rich in miR-146a-5p, which targets the TRAF6/NF-κB signaling pathway. In summary, the findings suggest that the integration of MSC-EVs with miR-137 may be a promising therapeutic strategy for ASD, which is worthy of clinical adoption.

Exosomes: A New Hope for Angiogenesis-Mediated Bone Regeneration.

Bone is a metabolically dynamic structure that is generally remodeled throughout the lifetime of an individual but often causes problems with increasing age. A key player for bone development and homeostasis, but also under pathological conditions, is the bone vasculature. This complex system of arteries, veins, and capillaries forms distinct structures where each subset of endothelial cells has important functions. Starting with the basic process of angiogenesis and bone-specific blood vessel formation, coupled with initial bone formation, the importance of different vascular structures is highlighted with respect to how these structures are maintained or changed during homeostasis, aging, and pathological conditions. After exemplifying the current knowledge on bone vasculature, this review will move on to exosomes, a novel hotspot of scientific research. Exosomes will be introduced starting from their discovery via current isolation procedures and state-of-the-art characterization to their role in bone vascular development, homeostasis, and bone regeneration and repair while summarizing the underlying signal transduction pathways. With respect to their role in these processes, especially mesenchymal stem cell-derived extracellular vesicles are of interest, which leads to a discussion on patented applications and an update on ongoing clinical trials. Taken together, this review provides an overview of bone vasculature and bone regeneration, with a major focus on how exosomes influence this intricate system, as they might be useful for therapeutic purposes in the near future.

Repair effect of human umbilical cord mesenchymal stem cell-derived small extracellular vesicles on ovarian injury induced by cisplatin.

Small extracellular vesicles (sEVs) secreted by human umbilical cord have therapeutic effects on various degenerative diseases. However, the characteristics and potential functions of human umbilical cord mesenchymal stem cells (huMSCs)-derived sEVs, especially the role of premature ovarian failure (POF), are poorly understood. Here, we isolated and characterized huMSCs and their sEVs. huMSCs highly expressed CD73, CD90, and CD105. huMSC-sEVs showed typical exosomal features, highly expressing CD9, TSG101, and CD63. It was shown that huMSC-sEVs could be taken up by granulosa cells (GCs) and damaged ovarian tissue, which increased the levels of hormone secretion and reduced GCs apoptosis. We further confirmed that the levels of follicle-stimulating hormone in rat serum decreased dramatically, while the levels of estrogen (E2）and anti-mullerian hormone (AMH) increased significantly with the treatment of huMSC-sEVs. Meanwhile, huMSC-sEVs treatment greatly reduced cell apoptosis and autophagy, while increased the phosphorylation levels of p-PI3K and p-Akt. Therefore, treatment with huMSC-sEVs significantly inhibited GCs apoptosis, improved ovarian morphology, promoted follicular development, inhibited follicular over-atresia, and improved ovarian reserve capacity in POF rats. Our study verified that activation of PI3K/Akt signaling pathway and regulation of cellular autophagy, thus reducing GCs death, are the mechanisms by which huMSC-sEVs restore ovarian tissue function.

Injectable hydrogel harnessing foreskin mesenchymal stem cell-derived extracellular vesicles for treatment of chronic diabetic skin wounds

Chronic skin wounds are a serious complication of diabetes with a high incidence rate, which can lead to disability or even death. Previous studies have shown that mesenchymal stem cells derived extracellular vesicles (EVs) have beneficial effects on wound healing. However, the human foreskin mesenchymal stem cell (FSMSCs)-derived extracellular vesicle (FM-EV) has not yet been isolated and characterized. Furthermore, the limited supply and short lifespan of EVs also hinder their practical use. In this study, we developed an injectable dual-physical cross-linking hydrogel (PSiW) with self-healing, adhesive, and antibacterial properties, using polyvinylpyrrolidone and silicotungstic acid to load FM-EV. The EVs were evenly distributed in the hydrogel and continuously released. In vivo and vitro tests demonstrated that the synergistic effect of EVs and hydrogel could significantly promote the repair of diabetic wounds by regulating macrophage polarization, promoting angiogenesis, and improving the microenvironment. Overall, the obtained EVs-loaded hydrogels developed in this work exhibited promising applicability for the repair of chronic skin wounds in diabetes patients.

Mesenchymal stem cell‐derived extracellular vesicles: Recent therapeutics and targeted drug delivery advances

AbstractThe targeted drug delivery field is rapidly advancing, focusing on developing biocompatible nanoparticles that meet rigorous criteria of non‐toxicity, biocompatibility, and efficient release of encapsulated molecules. Conventional synthetic nanoparticles (SNPs) face complications such as elevated immune responses, complex synthesis methods, and toxicity, which restrict their utility in therapeutics and drug delivery. Extracellular vesicles (EVs) have emerged as promising substitutes for SNPs, leveraging their ability to cross biological barriers, biocompatibility, reduced toxicity, and natural origin. Notably, mesenchymal stem cell‐derived EVs (MSC‐EVs) have garnered much curiosity due to their potential in therapeutics and drug delivery. Studies suggest that MSC‐EVs, the central paracrine contributors of MSCs, replicate the therapeutic effects of MSCs. This review explores the characteristics of MSC‐EVs, emphasizing their potential in therapeutics and drug delivery for various diseases, including CRISPR/Cas9 delivery for gene editing. It also delves into the obstacles and challenges of MSC‐EVs in clinical applications and provides insights into strategies to overcome the limitations of biodistribution and target delivery.

Quercetin-loaded Human Umbilical cord Mesenchymal Stem Cell-derived sEVs for Spinal Cord Injury Recovery

Following spinal cord injury, the inflammatory environment at the injury site causes local microglia and astrocytes to activate, which worsens the nerve damage in the affected area. Quercetin, an anti-inflammatory agent, has been limited in spinal cord injury due to its poor water solubility and easy degradation. Stem cell-derived extracellular vesicles can go through the blood–brain barrier and are an ideal drug delivery system. In this study, umbilical cord mesenchymal stem cell-derived extracellular vesicles were used to load quercetin to prevent its degradation and allow it to accumulate at the site of spinal cord injury. Our results showed that quercetin-loaded extracellular vesicles could inhibit the activation of microglia to M1 phenotype through the TLR4/NF-κB pathway, and the activation of astrocytes to A1 phenotype through the JAK2/STAT3 pathway. This reduced the production of inflammatory factors, mitigated neuronal damage, and inhibited the growth of astroglial scar, but promoted the recovery of motor function in rats with spinal cord injury.

Bone marrow mesenchymal stem cell-derived extracellular vesicles promote corneal epithelial repair and suppress apoptosis via modulation of Caspase-3 in vitro.

Corneal injuries are the major cause of blindness and visual impairment. Available treatments are limited by their efficacy and side effects. Mesenchymal stem cell-derived extracellular vesicles are presumed as functional equivalents and potential candidates for cell-free therapy. This study reports isolation and characterization of extracellular vesicles from human bone marrow mesenchymal stem cells and evaluates their role in mediating epithelial repair and apoptosis in cultured corneal epithelial cells through scratch assay, PCR, immunofluorescence, and flow cytometry in vitro. The isolated extracellular vesicles were spherical, < 150 nm in diameter, and characterized as CD9+, CD63+, CD81+, TSG101+, and Calnexin-. Further, these vesicles promoted corneal epithelial repair by enhancing proliferation and suppressed apoptosis by regulating the expression of BAD, P53, BCL-2, and cleaved CASPASE-3. Thus, our results suggest that BM-MSC-EVs might have the potential to be used for the treatment of injury-induced corneal epithelial defects. Clinical translation of this work would require further investigations.

Mesenchymal Stem Cells and Extracellular Vesicles: Therapeutic Potential in Organ Transplantation.

At present, organ transplantation remains the most appropriate therapy for patients with end-stage organ failure. However, the field of organ transplantation is still facing many challenges, including the shortage of organ donors, graft function damage caused by organ metastasis, and antibody-mediated immune rejection. It is therefore urgently necessary to find new and effective treatment. Stem cell therapy has been regarded as a "regenerative medicine technology." Mesenchymal stem cells (MSCs), as the most common source of cells for stem cell therapy, play an important role in regulating innate and adaptive immune responses and have been widely used in clinical trials for the treatment of autoimmune and inflammatory diseases. Increasing evidence has shown that MSCs mainly rely on paracrine pathways to exert immunomodulatory functions. In addition, mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are the main components of paracrine substances of MSCs. Herein, an overview of the application of the function of MSCs and MSC-EVs in organ transplantation will focus on the progress reported in recent experimental and clinical findings and explore their uses for graft preconditioning and recipient immune tolerance regulation. Additionally, the limitations on the use of MSC and MSC-EVs are also discussed, covering the isolation of exosomes and preservation techniques. Finally, the opportunities and challenges for translating MSCs and MSC-EVs into clinical practice of organ transplantation are also evaluated.

Proteomic insights uncover enhanced neurotherapeutic potential in conditioned mesenchymal stem cell-derived extracellular vesicles

Extracellular vesicles (EVs) show more potential as therapeutic agents for treating neurological disorders than their parent cells like MSCs. Notably, the therapeutic efficacy of MSCs can be boosted by inflammation factors and oxidative stressors. Here, we investigated the impact of activated microglial cell supernatant (Con1) and hydrogen peroxide (Con2) on MSCs and collected their derived EVs, followed by using high-resolution mass spectrometry to analyze MSC-EV proteomic and phosphoproteomic profiles, and verified the indicated functional protein and phosphorylated kinase as well. Our findings showed that both Con1 and Con2 EVs exhibited characteristic features of extracellular vesicles and possessed greater anti-inflammatory and antioxidant activity compared to unconditioned MSC-EVs. Omics analysis revealed alterations in protein expression and phosphorylation associated with inflammation and oxidation biological processes and signaling pathways, as well as signified the post-translational modification of proteins in Con1/2 EVs. Importantly, we identified that the anti-inflammatory role of MSC-EVs was linked to the serine/threonine kinase phosphorylation, and inhibition of insulin-like growth factor 1 receptor (IGF1R) reduced the antioxidant activity of MSC-EVs. This report documented the changed protein expression and phosphorylated patterns of Con1/2 EVs, and provided insights into the functionalization mode of MSC-EVs, suggesting the enhanced neurotherapeutic potential of conditioned EVs in the treatment of neurological diseases.