Minimal information for studies of extracellular vesicles 2018 (MISEV2018): a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

Al-Based Metal-Organic Nanoslice-Coupled Phospholipid Layer Enables Highly Enriched Biological External Vesicles

Systematic analysis of the information content of biological external vesicles (BEVs) is essential for understanding the complex relationships between metabolic processes and cells at a systemic level. Although considerable efforts have been made to enrich BEVs, their comprehensive analysis in a way that maintains and stabilizes information maintenance at high doses remains a challenge. To address this issue, we developed a metal-organic nanoslice-coupled exocytosis phospholipid layer method that utilized subtle interactions between the metal-organic nanoslice and the phospholipid molecular layer of the membrane to achieve the convenient and efficient enrichment of BEVs. The method bypassed the conventional ultracentrifugation and size exclusion separation and helped to highly preserve the internal information on BEVs. By integrating and analyzing the enriched BEVs for elements such as membrane proteins and endotoxins, the simplicity and robustness of the metal-organic nanoslice-coupled vesicle surface phospholipid layer technology were verified, which provided a reliable platform for studying the cellular events associated with outer vesicles and expanded the biological applications of the metal-organic nanoslice.

Extracellular vesicles and preterm infant diseases

With the continuous improvement in perinatal care, the number of viable preterm infants is gradually increasing, along with the rise in preterm-related diseases such as necrotizing enterocolitis, bronchopulmonary dysplasia, perinatal brain injury, retinopathy of prematurity, and sepsis. Due to the unique pathophysiology of preterm infants, diagnosing and treating these diseases has become particularly challenging, significantly affecting their survival rate and long-term quality of life. Extracellular vesicles (EVs), as key mediators of intercellular communication, play an important regulatory role in the pathophysiology of these diseases. Because of their biological characteristics, EVs could serve as biomarkers and potential therapeutic agents for preterm-related diseases. This review summarizes the biological properties of EVs, their relationship with preterm-related diseases, and their prospects for diagnosis and treatment. EVs face unique challenges and opportunities for clinical applications.

Identification of exosome-related genes associated with prognosis and immune infiltration features in pancreatic cancer

BACKGROUND

This study is designed to explore the prognostic significance of exosome-related genes (ERGs) and their impact on the the tumor microenvironment (TME) of pancreatic cancer.

METHODS

Transcriptomic data alongside clinical details of patients with PC were retrieved from both The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) repository. A collection of 121 exosome-associated genes were obtained from the ExoBCD database. For constructing a risk scoring model, the absolute shrinkage and selection operator (LASSO) regression method was employed. Gene set enrichment and variance analyses were facilitated by the clusterProfiler and GSVA R software tools. Additionally, CIBERSORT was used to estimate immune cell infiltration levels. Lastly, the TIDE algorithm was leveraged to evaluate the connection between gene expression and drug sensitivity. A series of experiments were used to verify the role of DLGAP5 in PC.

RESULTS

Two unique molecular clusters were uncovered, and our analysis revealed a connection between ERG dysregulation across multiple layers and patient demographic, histopathological attributes, prognosis, as well as immune cell infiltration patterns within the TME. An ERG_score was developed for forecasting overall survival and its predictive capacity was confirmed in PC cases. A precise nomogram was established to enhance the clinical utility of the ERG_score. Patients in the low-risk group exhibited higher immune and ESTIMATE scores than that in the high-risk group, displaying an improved overall survival (OS). The ERG_score was associated with cancer stem cell (CSC) index and drug sensitivity. Crucial evaluations of ERGs illuminated the significance of DLGAP5, emphasizing its expression in PC and its contributory role in tumor growth stimulation.

CONCLUSIONS

Our investigation reveals a correlation between the exosome-related risk assessment signature and the survival outcome as well as immune cell infiltration in patients with PC. This finding potentially paves the way for enhanced therapeutic strategies for PC.

An ex vivo and in vitro investigation of extracellular vesicle interactions with B cells of Macaca nemestrina and humans

Extracellular vesicles may modify recipient cell behavior through multiple mechanisms, including interacting with the cell surface or internal membrane components and delivering luminal cargo to the cytoplasm. Here, we use a previously established ex vivo approach to investigate the cellular fate of EVs spiked into whole blood samples from nonhuman primate (NHP) and human donors and contrast these findings with results from in vitro assays. We report that EVs are internalized by NHP and human B cells while also associating to some degree with other PBMCs. EVs exhibit greater association with B cells in ex vivo whole blood compared to isolated B cells, suggesting that blood components may promote EV interactions or that cell isolation factors may inhibit this association. Cellular uptake of EVs involves clathrin-dependent endocytosis and may be aided by other pathways, including direct EV-cell membrane fusion. Overall, our data suggest that EV association, including uptake, by B cells occurs in at least two primate species. These findings highlight the potential to develop new strategies to either enhance or inhibit EV tropism toward B cells.

Real-World Evidence of Bevacizumab and Panitumumab Drug Resistance and Drug Ineffectiveness from EudraVigilance Database

Colorectal cancer (CRC) is the third most common cancer in the world, with an average 5-year overall survival (OS) rate of approximately 60% [...].

Recent advances in the application of engineered exosomes from mesenchymal stem cells for regenerative medicine

Exosomes, cell-derived vesicles produced by cells, are fascinating and drawing growing interest in biomedical exploration due to their exceptional properties. There is intriguing evidence that exosomes are involved in major biological processes, including diseases and regeneration. Exosomes from mesenchymal stem cells (MSCs) have shown promising outcomes in regenerative medicine. Numerous studies suggest that exosomes have several advantages over conventional synthetic nanocarriers, opening novel frontiers for innovative drug delivery. Regenerative medicine has demonstrated the profound therapeutic outcomes of engineered or loaded exosomes from MSCs. Different methods are being used to modify or/load exosomes. These exosomes can improve cell signaling pathways for bone and cartilage diseases, liver diseases, nerve tissues, kidney diseases, skin tissue, and cardiovascular diseases. Despite extensive research, clinical translation of these exosomes remains a challenge. The optimization of cargo loading methods, efficiency, physiological stability, and the isolation and characterization of exosomes present some challenges. The upcoming examination should include the development of large-scale, quality-controllable production approaches, the modification of drug loading approaches, and numerous in vivo investigations and clinical trials. Here, we provided an informative overview of the extracellular vesicles and modification/loading methods of exosomes. We discuss the last exosome research on regeneration disorders, highlighting the therapeutic applications of MSCs-derived exosomes. We also highlight future directions and challenges, underscoring the significance of addressing the main questions in the field.

Extracellular Vesicle-Based Strategies for Tumor Immunotherapy

Immunotherapy is one of the most promising approaches for cancer management, as it utilizes the intrinsic immune response to target cancer cells. Normally, the human body uses its immune system as a defense mechanism to detect and eliminate foreign objects, including cancer cells. However, cancers develop a 'switch off' mechanism, known as immune checkpoint proteins, to evade immune surveillance and suppress immune activation. Therefore, significant efforts have been made to develop the strategies for stimulating immune responses against cancers. Among these, the use of extracellular vesicles (EVs) to enhance the anti-tumor immune response has emerged as a particularly promising approach in cancer management. EVs possess several unique properties that elevate the potency in modulating immune responses. This review article provides a comprehensive overview of recent advances in this field, focusing on the strategic usage of EVs to overcome tumor-induced immune tolerance. We discuss the biogenesis and characteristics of EVs, as well as their potential applications in medical contexts. The immune mechanisms within the tumor microenvironment and the strategies employed by cancers to evade immune detection are explored. The roles of EVs in regulating the tumor microenvironment and enhancing immune responses for immunotherapy are also highlighted. Additionally, this article addresses the challenges and future directions for the development of EV-based nanomedicine approaches, aiming to improve cancer immunotherapy outcomes with greater precision and efficacy while minimizing off-target effects.

Extracellular vesicles and miRNA-based therapies in triple-negative breast cancer: advances and clinical perspectives

Triple-negative breast cancer (TNBC) is one of the most aggressive and challenging subtypes for treatment, due to the lack of hormone receptors and the human epidermal growth factor receptor 2 (HER2) protein. The identification of new molecular targets is important for the development of targeted and specific therapies for TNBC patients. MicroRNAs (miRNAs) have emerged as promising molecular targets, being involved in cellular processes such as cell survival, apoptosis, differentiation, carcinogenesis, and metastasis. Extracellular vesicles (EVs) have gained prominence in areas such as drug delivery, immune modulation, biomarkers for diagnosis and prognosis, and therapeutics, due to their use as vehicles for the delivery of miRNAs, regulation of gene expression, and development of combined therapeutic strategies. In particular, mesenchymal stem cell-derived EVs (MSC-derived EVs) can transfer proteins, mRNAs/miRNAs, or DNA molecules and are being considered safer treatment options due to their inability to directly form tumors and contain lower amounts of membrane proteins such as MHC molecules. Numerous studies have highlighted the role of miRNAs in EVs in TNBC tumorigenesis, with a focus on diagnosis, prognosis, treatment selection, and monitoring. However, the development of therapies with EVs, especially MSC-derived EVs, is still in its infancy. Therefore, the aim of this review is to address new therapeutic strategies based on the delivery of miRNAs through EVs, with a focus on MSC-derived EVs, for the treatment of TNBC as an innovative therapy in oncology.

Extracellular vesicles in tumor immunity: mechanisms and novel insights

Extracellular vesicles (EVs), nanoscale vesicles secreted by cells, have attracted considerable attention in recent years due to their role in tumor immunomodulation. These vesicles facilitate intercellular communication by transporting proteins, nucleic acids, and other biologically active substances, and they exhibit a dual role in tumor development and immune evasion mechanisms. Specifically, EVs can assist tumor cells in evading immune surveillance and attack by impairing immune cell function or modulating immunosuppressive pathways, thereby promoting tumor progression and metastasis. Conversely, they can also transport and release immunomodulatory factors that stimulate the activation and regulation of the immune system, enhancing the body's capacity to combat malignant diseases. This dual functionality of EVs presents promising avenues and targets for tumor immunotherapy. By examining the biological characteristics of EVs and their influence on tumor immunity, novel therapeutic strategies can be developed to improve the efficacy and relevance of cancer treatment. This review delineates the complex role of EVs in tumor immunomodulation and explores their potential implications for cancer therapeutic approaches, aiming to establish a theoretical foundation and provide practical insights for the advancement of future EVs-based cancer immunotherapy strategies.

Targeted knockdown of MSC-sEVs biogenesis regulator proteins to elucidate the mechanisms of their production: a step towards translational applications

In the intricate landscape of cellular communication, small extracellular vesicles (sEVs) originating from endosomes play crucial roles as mediators and have garnered significant attention in theranostics. Our understanding of sEV biogenesis largely stems from studies on cancer cells, which are vital for diagnostics. However, in therapeutics, where mesenchymal stromal cell (MSC)-derived sEVs are emerging as investigational new drugs, their biogenesis pathways remain largely unexplored. This article explores the parallel narratives of sEV biogenesis in cancer cells and stem cells, specifically using HeLa cells and MSCs as model cell lines. This study investigated the roles of key proteins-hepatocyte growth factor-regulated tyrosine kinase substrate (HRS), signal-transducing adaptor molecule (STAM), tumor susceptibility gene 101 (TSG101), and ALG-2-interacting protein X (ALIX)-as identified in HeLa cells, in the context of MSC-sEV biogenesis. While these proteins show similarities across cell types, a discernible difference arises in their primary functions in regulating sEV biogenesis. The critical role of ALIX in MSC-sEV biogenesis, in particular, underscores its potential as a target for modulating sEVs' yield in regenerative therapies. Through this comparative analysis, we identified shared molecular signatures, offering insights to guide therapeutic interventions and unlock the regenerative potential of stem cells.

COVID-19 extracellular vesicles display heterogeneity based on viral and host RNA expression: implications for host immune response

Viral RNA and miRNAs released by immune cells contribute to inflammation in COVID-19 patients. Here, we investigated the role of SARS-CoV2 RNA and host miRNAs carried within extracellular vesicles (EVs) in modulating inflammation. EVs were classified as positive or negative depending on their viral RNA cargo. To assess the function of viral RNA, EVs, and lipopolysaccharide (LPS) were used to stimulate whole blood samples from healthy subjects, and the secretion of 27 serum analytes was measured. EVs alone did not induce cytokines, chemokines, or growth factors. However, under LPS stimulation, (SARS-CoV2+) EVs increased IL-12 and decreased IL-13 secretion, while (SARS-CoV2-) EVs increased MIP-1α and IL-1β secretion. Host miR-19a-3p, -192-5p, -let-7c-5p, and -92b-3a were differentially expressed in association with viral RNA. EVs from COVID-19 patients exhibited differences in viral RNA and miRNA expression profiles that modulate LPS responses. This knowledge sheds light on the immunopathology of COVID-19.

Microglia-derived sEV: Friend or foe in the pathogenesis of cognitive impairment

As immune cells, microglia serve a dual role in cognition. Microglia-derived sEV actively contribute to the development of cognitive impairment by selectively targeting specific cells through various substances such as proteins, RNA, DNA, lipids, and metabolic waste. In recent years, there has been an increasing focus on understanding the pathogenesis and therapeutic potential of sEV. This comprehensive review summarizes the detrimental effects of M1 microglial sEV on pathogenic protein transport, neuroinflammation, disruption of the blood-brain barrier (BBB), neuronal death and synaptic dysfunction in relation to cognitive damage. Additionally, it highlights the beneficial effects of M2 microglia on alleviating cognitive impairment based on evidence from cellular experiments and animal studies. Furthermore, since microglial-secreted sEV can be found in cerebrospinal fluid or cross the BBB into plasma circulation, they play a crucial role in diagnosing cognitive impairment. However, using sEV as biomarkers is still at an experimental stage and requires further clinical validation. Future research should aim to explore the mechanisms underlying microglial involvement in various nervous system disorders to identify novel targets for clinical interventions.

Recent advances in SERS assays for detection of multiple extracellular vesicles biomarkers for cancer diagnosis

As the prevalence of cancer is escalating, there is an increased demand for early and sensitive diagnostic tools. A major challenge in early detection is the lack of specific biomarkers, and a readily accessible, sensitive and rapid detection method. To meet these challenges, cancer-derived small extracellular vesicles (sEVs) have been discovered as a new promising cancer biomarker due to the high abundance of sEVs in body fluids and their extensive cargo of biomarkers. Additionally, surface-enhanced Raman scattering (SERS) presents a sensitive, multiplexed, and rapid method that has gained attraction with recent studies showing promising results from patient samples for the multiplex detection of cancer sEVs. Various label-based SERS multiplex assays have been developed in the field of SERS including bead assays, lateral flow immunoassays, microfluidic devices, and artificial intelligence (AI)-based label-free SERS chips, targeting multiple surface proteins to ensure comprehensive multiplex diagnostics. These assays hold promise for enabling early detection, quantification, and subtyping of cancer-derived sEVs for cancer diagnostic applications. This review aims to provide a summary of the recent advances in the field of SERS multiplex assays for detection, quantification, and subtyping of sEVs to facilitate cancer diagnosis. This review further provides unique insights into the use of sEVs as a biomarker and aims to address the issues surrounding their translation from laboratories to clinics.

The proteomic landscape of stool-derived extracellular vesicles in patients with pre-cancerous lesions and colorectal cancer

Colorectal cancer (CRC) is the 2nd most fatal cancer in the United States, but when detected early it is highly curable. Stool-derived extracellular vesicles (EVs) are a novel biomarker source that could augment the sensitivity for detection of CRC precursors. However, standardization of isolation methods for stool-derived EVs remains underexplored. We previously reported that size-exclusion chromatography (SEC) followed by ultrafiltration (UF-100kDa) was suitable for human stool supernatant EV isolation. In this study, we first assess alternative EV concentration methods (ultrafiltration [UF]; 10 kDa, 30 kDa, 50 kDa, 100 kDa and speed vacuum [SV]). Second, we investigate the host/bacterial EV proteomes by mass spectrometry. We report no difference in recovery, RNA and soluble protein contamination among concentration methods. Proteomic analysis reveals a diverse bacterial proteome, while human-derived proteins are more abundant. Specifically, pancreatic enzymes are among the most abundant proteins, further exploration revealed that zymogen granules are likely co-isolated in stool EV preparations. To enable discovery of EV-based molecular signatures of CRC precursors with high sensitivity, immunocapture strategies will likely be needed. Notably, we identified 10 surface proteins that may serve as candidates for the purification of colon-derived EVs. This work serves as framework for the future discovery and validation of EV-based biomarkers for CRC.

Modulation of β-Catenin promotes WNT expression in macrophages and mitigates intestinal injury

BACKGROUND

Macrophages are the major source of WNT ligands. However, the regulation of WNT expression in macrophages has not been studied. In the present study, we have discovered that activation of canonical β-Catenin signaling suppresses WNT expression in macrophages. EVs from these pre-conditioned macrophages promoted intestinal stem cell regeneration and mitigated intestinal injury.

METHOD

ChIP-seq analysis and validation studies using recombinant DNA construct expressing Luciferase reporter under WNT promoter (e.g. WNT5a and WNT9b) were conducted to demonstrate the involvement of β-Catenin in the transcriptional regulation of WNT expression. The regulatory role of β-Catenin in WNT expression in macrophages was examined by treating these cells with a Tankyrase inhibitor. In addition, the gene expressing β-Catenin was deleted in macrophages using Csf1r.iCre; Ctnnb1fl/fl mice model. Both pharmacological and genetically modulated macrophages were examined for WNT expression and activity by qPCR and TCF/LEF luciferase assay respectively. Additionally, Csf1r.iCre; Ctnnb1fl/fl mice were exposed to irradiation to compare the radiosensitivity with their wildtype littermate. Extracellular vesicles (EVs) were isolated from pre-conditioned WNT-enriched macrophages and infused in irradiated C57BL/6 and Lgr5/eGFP-IRES-Cre-ERT2; R26-ACTB-tdTomato-EGFP mice to determine the regenerative response of intestinal stem cell (ISC) and epithelial repair. Regenerative effects of EVs were also examined in mice model DSS induced colitis.

RESULT

ChIP-seq analysis and subsequent validation study suggested physical association of β-Catenin with WNT promoters to suppress WNT expression. Macrophage specific deletion of gene expressing β-Catenin or pharmacological inhibition of Tankyrase improves the WNT expression in macrophages several folds compared to control. Transfusion of these preconditioned macrophages or EVs from these cells delivers optimum level of morphogenic WNT to injured epithelium, activates ISC regeneration and mitigated radiation induced intestinal injury. Intestinal epithelium in Csf1r.iCre; Ctnnb1fl/fl mice also showed radioresistance compared to wild type littermate. Moreover, EVs derived from WNT enriched macrophages can mitigate intestinal injury in mice model of DSS induced acute colitis.

CONCLUSION

The study provides substantial evidence that macrophage-targeted modulation of canonical WNT signaling induces WNT expression in macrophages. Treatment with preconditioned macrophage derived WNT-enriched EVs can be a promising therapeutic approach against intestinal injury.

Extracellular vesicles: from intracellular trafficking molecules to fully fortified delivery vehicles for cancer therapeutics

Extracellular vesicles (EVs) are emerging as viable tools in cancer treatment due to their ability to carry a wide range of theranostic activities. This review summarizes different forms of EVs such as exosomes, microvesicles, apoptotic bodies, and oncosomes. It also sheds the light onto isolation methodologies, characterization techniques and therapeutic applications of all discussed EVs. Evidence indicates that EVs are particularly effective in delivering chemotherapeutic medications, and immunomodulatory agents. However, the advancement of EV-based therapies into clinical practice is hindered by challenges including EVs heterogeneity, cargo loading efficiency, and in vivo stability. Overall, EVs have the potential to change cancer therapeutic paradigms. Continued research and development activities are critical for improving EV-based medications and increasing their therapeutic impact.

Extracellular Vesicles as Biomarkers in Infectious Diseases

Extracellular vesicles (EVs) are nanosized vesicles that are secreted by all cells into the extracellular space. EVs are involved in cell-to-cell communication and can be found in different bodily fluids (bronchoalveolar lavage fluid, sputum, and urine), tissues, and in circulation; the composition of EVs reflects the physiological condition of the releasing cell. The ability to use EVs from bodily fluids for minimally invasive detection to monitor diseases makes them an attractive target. EVs carry a snapshot of the releasing cell's internal state, and they can serve as powerful biomarkers for diagnosing diseases. EVs also play a role in the body's immune and pathogen detection responses. Pathogens, such as bacteria and viruses, can exploit EVs to enhance their survival and spread and to evade detection by the immune system. Changes in the number or contents of EVs can signal the presence of an infection, offering a potential avenue for developing new diagnostic methods for infectious diseases. Ongoing research in this area aims to address current challenges and the potential of EVs as biomarkers in diagnosing a range of diseases, including infections and infectious diseases. There is limited literature on the development of EVs as diagnostic biomarkers for infectious diseases using existing molecular biology approaches. We aim to address this gap by reviewing recent EV-related investigations in infectious disease studies.

Advances in small extracellular vesicles: roles in the tumor microenvironment and epithelial ovarian cancer diagnosis and treatment

Epithelial ovarian cancer (EOC), one of the most prevalent subtypes of ovarian cancer, has a 5-year survival rate of less than 30%, highlighting the urgent need for novel diagnostic and therapeutic strategies. The tumor microenvironment (TME), a critical regulator of tumor progression, includes various components, among which small extracellular vesicles (sEVs) serve as important molecular carriers, having gained attention as significant contributors to cancer biology. These vesicles, released by cells into the extracellular space, are pivotal in the pathogenesis of EOC. In addition, sEVs show significant promise as biomarkers and therapeutic agents for the treatment and management of this malignancy. This review explores recent advancements in the understanding of sEVs within the TME and their potential applications in the diagnosis and treatment of EOC.

Quality Control of Fetal Wharton's Jelly Mesenchymal Stem Cells-Derived Small Extracellular Vesicles

Background

Quality control (QC) is an important element in ensuring drug substances' safety, efficacy, and quality. The dosing regimen for sEVs can be in the form of protein concentration or the number of particles based on the results of a series of quality controls applied as in-process control.

Methods

Wharton's Jelly Mesenchymal Stem Cells (WJMSCs) were isolated from four independent umbilical cord samples and were characterized following the International Society for Cellular Therapy (ISCT) guidelines. Small extracellular vesicles (sEVs) were isolated separately from these four WJMSCs samples using the Tangential Flow Filtration (TFF) method and were characterized per Minimal Information for Studies of Extracellular Vesicles (MISEV2018) guidelines. Each isolated and concentrated sEV preparation was standardized and its purity was determined by the ratio of the number of particles to protein concentration.

Results

All the WJMSCs samples passed the Mesenchymal Stem Cells (MSCs) characterization QC tests. Qualitatively, EVs-positive markers (CD63 and TSG101) and intact bilipid membrane vesicles were detected in all the sEV preparations. Quantitatively, the protein and particle concentrations revealed that all the sEV preparations were "impure" with < 1.5 × 109 particles/µg protein. Albumin was co-isolated in all the sEV preparations.

Conclusion

In short, all characterized and standardized individual and pooled sEV preparations were deemed "impure" due to albumin co-isolation using the TFF method. For therapeutic development, it is essential to report protein and particle concentrations in EV preparations based on these QC results.

Pre-Concentration Freezing Alters the Composition of Mesenchymal Stem/Stromal Cell-Conditioned Medium

Batch-to-batch reproducibility and robust quality assessment are crucial for producing cell-free biologics, such as conditioned medium (CM) derived from mesenchymal stem/stromal cells (MSCs). This study investigated the effects of freezing CM at -80 °C prior to concentration, a step that could occur in large scale pipelines, compared to freshly processed CM. Quality assessment included total protein quantification; extracellular vesicle evaluation using nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and cytofluorimetry; and biochemical analysis using Raman spectroscopy. The freezing process resulted in a 34% reduction in total protein content, as confirmed for selected bioactive mediators, and significant depletion of specific particle types, particularly larger ones. Interestingly, the total particle concentration and polydispersity remained stable. Alterations in Raman spectra highlighted changes in protein, lipid, and nucleic acid content. These findings demonstrate that even routine steps like freezing can alter CM composition, likely due to temperature-induced structural changes in biological molecules. Careful consideration of pre- and intra-processing handling temperatures is critical for preserving the integrity of CM and ensuring consistent quality. This study emphasizes the importance of refining manufacturing protocols in the production of cell-free biologics.

Bioelectric stimulation outperforms brain derived neurotrophic factor in promoting neuronal maturation

Neuronal differentiation and maturation are crucial for developing research models and therapeutic applications. Brain-derived neurotrophic factor (BDNF) is a widely used biochemical stimulus for promoting neuronal maturation. However, the broad effects of biochemical stimuli on multiple cellular functions limit their applicability in both in vitro models and clinical settings. Electrical stimulation (ES) offers a promising physical method to control cell fate and function, but it is hampered by lack of standard and optimised protocols. In this study, we demonstrate that ES outperforms BDNF in promoting neuronal maturation in human neuroblastoma SH-SY5Y. Additionally, we address the question regarding which ES parameters regulate biological responses. The neuronal differentiation and maturation of SH-SY5Y cells were tested under several pulsed ES regimes. We identified accumulated charge and effective electric field time as novel criteria for determining optimal ES regimes. ES parameters were obtained using electrochemical characterisation and equivalent circuit modelling. Our findings show that neuronal maturation in SH-SY5Y cells correlates with the amount of accumulated charge during ES. Higher charge accumulation (~ 50 mC/h) significantly promotes extensive neurite outgrowth and ramification, and enhances the expression of synaptophysin, yielding effects exceeding those of BDNF. In contrast, fewer charge injection to the culture (~ 0.1 mC/h) minimally induces maturation but significantly increases cell proliferation. Moreover, ES altered the concentration and protein cargo of secreted extracellular vesicles (EV). ES with large enough accumulated charge significantly enriched EV proteome associated with neural development and function. These results demonstrate that each ES regime induces distinct cellular responses. Increased accumulated charge facilitates the development of complex neuronal morphologies and axonal ramification, outperforming exogenous neurotrophic factors. Controlled ES methods are immediately applicable in creating mature neuronal cultures in vitro with minimal chemical intervention.

A 'torn bag mechanism' of small extracellular vesicle release via limiting membrane rupture of en bloc released amphisomes (amphiectosomes)

Recent studies showed an unexpected complexity of extracellular vesicle (EV) biogenesis pathways. We previously found evidence that human colorectal cancer cells in vivo release large multivesicular body-like structures en bloc. Here, we tested whether this large EV type is unique to colorectal cancer cells. We found that all cell types we studied (including different cell lines and cells in their original tissue environment) released multivesicular large EVs (MV-lEVs). We also demonstrated that upon spontaneous rupture of the limiting membrane of the MV-lEVs, their intraluminal vesicles (ILVs) escaped to the extracellular environment by a 'torn bag mechanism'. We proved that the MV-lEVs were released by ectocytosis of amphisomes (hence, we termed them amphiectosomes). Both ILVs of amphiectosomes and small EVs separated from conditioned media were either exclusively CD63 or LC3B positive. According to our model, upon fusion of multivesicular bodies with autophagosomes, fragments of the autophagosomal inner membrane curl up to form LC3B positive ILVs of amphisomes, while CD63 positive small EVs are of multivesicular body origin. Our data suggest a novel common release mechanism for small EVs, distinct from the exocytosis of multivesicular bodies or amphisomes, as well as the small ectosome release pathway.

miRNA in blood-brain barrier repair: role of extracellular vesicles in stroke recovery

Ischemic stroke is a leading cause of mortality and long-term disability globally. One of its aspects is the breakdown of the blood-brain barrier (BBB). The disruption of BBB's integrity during stroke exacerbates neurological damage and hampers therapeutic intervention. Recent advances in regenerative medicine suggest that mesenchymal stem cells (MSCs) derived extracellular vesicles (EVs) show promise for restoring BBB integrity. This review explores the potential of MSC-derived EVs in mediating neuroprotective and reparative effects on the BBB after ischemic stroke. We highlight the molecular cargo of MSC-derived EVs, including miRNAs, and their role in enhancing angiogenesis, promoting the BBB and neural repair, and mitigating apoptosis. Furthermore, we discuss the challenges associated with the clinical translation of MSC-derived EV therapies and the possibilities of further enhancing EVs' innate protective qualities. Our findings underscore the need for further research to optimize the therapeutic potential of EVs and establish their efficacy and safety in clinical settings.

Exploring RNA cargo in extracellular vesicles for pleural mesothelioma detection

BACKGROUND

Pleural Mesothelioma (PM) is a highly aggressive cancer, for which effective early detection remains a challenge due to limited screening options and low sensitivity of biomarkers discovered so far. While extracellular vesicles (EVs) have emerged as promising candidates for blood-based biomarkers, their role in PM has not been studied yet. In this study, we characterized the transcriptomic profile of EVs secreted by PM primary cells and explored their potential as a biomarker source for PM detection.

METHODS

We collected cell culture supernatant from early-passage PM cell cultures derived from the pleural effusion of 4 PM patients. EVs were isolated from the supernatant using Qiagen exoEasy Maxi kit. RNA isolation from EVs was done using the mirVana PARIS kit. Finally, single-end RNA sequencing was done with Illumina Novaseq 6000.

RESULTS

We identified a range of RNA species expressed in EVs secreted by PM cells, including protein-coding RNA (80%), long non-coding RNA (13%), pseudogenes (4.5%), and short non-coding RNA (1.6%). We detected a subset of genes associated with the previously identified epithelioid (32 genes) and sarcomatoid molecular components (36 genes) in PM-EVs. To investigate whether these markers could serve as biomarkers for PM detection in blood, we compared the RNA content of PM-EVs with the cargo of EVs isolated from the plasma of healthy donors (publicly available data). Majority of upregulated genes in PM-EVs were protein-coding and long non-coding RNAs. Interestingly, 25 of them were the sarcomatoid and epithelioid marker genes. Finally, functional analysis revealed that the PM-EV RNA cargo was associated with Epithelial-Mesenchymal transition, glycolysis, and hypoxia.

CONCLUSIONS

This is the first study to characterize the transcriptomic profile of EVs secreted by PM primary cell cultures, demonstrating their potential as biomarker source for early detection. Further investigation of the functional role of PM-EVs will provide new insights into disease biology and therapeutic avenues.

TGF-β induces cholesterol accumulation to regulate the secretion of tumor-derived extracellular vesicles

BACKGROUND

Cancer cells are avid extracellular vesicle (EV) producers. EVs transport transforming growth factor-β (TGF-β), which is commonly activated under late stages of cancer progression. Nevertheless, whether TGF-β signaling coordinates EV biogenesis is a relevant topic that remains minimally explored.

METHOD

We sought after specific TGF-β pathway mediators that could regulate EV release. To this end, we used a large number of cancer cell models, coupled to EV cell biological assays, unbiased proteomic and transcriptomic screens, followed by signaling and cancer biology analyses, including drug resistance assays.

RESULTS

We report that TGF-β, by activating its type I receptor and MEK-ERK1/2 signaling, increased the numbers of EVs released by human cancer cells. Upon examining cholesterol as a mediator of EV biogenesis, we delineated a pathway whereby ERK1/2 acted by phosphorylating sterol regulatory element-binding protein-2 that transcriptionally induced 7-dehydrocholesterol reductase expression, thus raising cholesterol abundance at both cellular and EV levels. Notably, inhibition of MEK or cholesterol synthesis, which impaired TGF-β-induced EV secretion, sensitized cancer cells to chemotherapeutic drugs. Furthermore, proteomic profiling of two distinct EV populations revealed that EVs secreted by TGF-β-stimulated cells were either depleted or enriched for different sets of cargo proteins. Among these, latent-TGF-β1 present in the EVs was not affected by TGF-β signaling, while TGF-β pathway-related molecules (e.g., matrix metalloproteinases, including MMP9) were either uniquely enriched on EVs or strongly enhanced after TGF-β stimulation. EV-associated latent-TGF-β1 activated SMAD signaling, even when EV uptake was blocked by heparin, indicating competent signaling capacity from target cell surface receptors. MMP inhibitor or proteinase treatment blocked EV-mediated SMAD signaling, suggesting that EVs require MMP activity to release the active TGF-β from its latent complex, a function also linked to the EV-mediated transfer of pro-migratory potential and ability of cancer cells to survive in the presence of cytotoxic drugs.

CONCLUSION

Hence, we delineated a novel signaling cascade that leads to high rates of EV generation by cancer cells in response to TGF-β, with cholesterol being a key intermediate step in this mechanism.

Size distribution of extracellular vesicles in pretreatment ascites and plasma is correlated with primary treatment outcome in advanced high-grade serous carcinoma

To improve the treatment outcome and survival of patients with advanced high-grade serous carcinoma (HGSC), prognostic biomarkers for assessing the feasibility of complete (R0) or optimal (R1) primary cytoreductive surgery are needed. Additionally, biomarkers for predicting the response to neoadjuvant chemotherapy (NACT) in patients with primary inoperable disease could help stratify patients for tailored therapy and improve personalised approach. Such promising biomarkers are extracellular vesicles (EVs), which are present in ascites and plasma and are available for minimally invasive liquid biopsy. EV concentration and EV molecular profile have been at the forefront of research in the field of biomarkers for many years now, but recent studies have highlighted the importance of EV size distribution. Our study aimed to evaluate the potential of the EV concentration and size distribution in pretreatment ascites and plasma samples from patients with advanced HGSC as prognostic biomarkers. In our prospective cohort study, nanoparticle tracking analysis (NTA) was used to determine EV characteristics in paired pretreatment ascites and plasma samples from 37 patients with advanced HGSC. Patients were treated with primary cytoreductive surgery followed by adjuvant chemotherapy (ACT) (N = 15) or NACT followed by interval debulking surgery (IDS) when optimal cytoreduction was not feasible (N = 22). The correlations of the EV concentration and size distribution in ascites and plasma with treatment outcome, progression-free survival (PFS) and overall survival (OS) were analysed. We found a significant correlation between the EV size distribution in ascites and residual disease after primary cytoreductive surgery. Larger EVs in ascites correlated with worse resection success after primary cytoreductive surgery. A significant correlation between the D10 value of EVs in plasma and the chemotherapy response score (CRS) after NACT was observed. A smaller D10 value of plasma EVs was correlated with a better chemotherapy response. Receiver operating characteristic (ROC) curve analysis revealed excellent performance for D10 value in ascites for the prediction of suboptimal (R2) resection at primary debulking surgery and excellent performance for D10 value in plasma for the prediction of complete or near-complete chemotherapy response score (CRS 3) at interval debulking surgery. There was a significant correlation between the mean diameter, D90 value and proportion of medium/large (> 200 nm) EVs in ascites and those in plasma. On the other hand, there was no correlation of the EV concentration or D10 and D50 values between the ascites fluid and plasma samples. Our results indicate that the EV size distribution in ascites has the potential to predict resection success after primary cytoreductive surgery and that the EV size distribution of the smallest EVs in plasma might help predict the chemotherapy response of patients treated with NACT. In the future, molecular analyses of size-dependent EV cargo could provide more insight into their biological functions and potential as predictive biomarkers.

Mesenchymal stem cells and their extracellular vesicle therapy for neurological disorders: traumatic brain injury and beyond

Traumatic brain injury (TBI) is a complex condition involving mechanisms that lead to brain dysfunction and nerve damage, resulting in significant morbidity and mortality globally. Affecting ~50 million people annually, TBI's impact includes a high death rate, exceeding that of heart disease and cancer. Complications arising from TBI encompass concussion, cerebral hemorrhage, tumors, encephalitis, delayed apoptosis, and necrosis. Current treatment methods, such as pharmacotherapy with dihydropyridines, high-pressure oxygen therapy, behavioral therapy, and non-invasive brain stimulation, have shown limited efficacy. A comprehensive understanding of vascular components is essential for developing new treatments to improve blood vessel-related brain damage. Recently, mesenchymal stem cells (MSCs) have shown promising results in repairing and mitigating brain damage. Studies indicate that MSCs can promote neurogenesis and angiogenesis through various mechanisms, including releasing bioactive molecules and extracellular vesicles (EVs), which help reduce neuroinflammation. In research, the distinctive characteristics of MSCs have positioned them as highly desirable cell sources. Extensive investigations have been conducted on the regulatory properties of MSCs and their manipulation, tagging, and transportation techniques for brain-related applications. This review explores the progress and prospects of MSC therapy in TBI, focusing on mechanisms of action, therapeutic benefits, and the challenges and potential limitations of using MSCs in treating neurological disorders.

Neural progenitor cell-derived exosomes in ischemia/reperfusion injury in cardiomyoblasts

The physiologic relationship between the brain and heart is emerging as a novel therapeutic target for clinical intervention for acute myocardial infarction. In the adult human brain, vestigial neuronal progenitor stem cells contribute to neuronal repair and recovery following cerebral ischemic injury, an effect modulated by secreted exosomes. Ischemia conditioned neuronal cell derived supernatant and experimental stroke has been shown to be injurious to the heart. However, whether unconditioned neuronal progenitor cell derived-exosomes can instead protect myocardium represents a profound research gap. We investigated the effects of unconditioned neural stem cell derived exosomes as post-injury treatment for cardiomyoblasts from three neuronal culture conditions; adherent cultures, neurosphere cultures and bioreactor cultures. Small extracellular vesicles were enriched with serial ultracentrifugation, validated via nanoparticle tracking analysis, transmission electron microscopy and Western blot analysis prior to utilization as post-injury treatment for H9c2 cardiomyoblasts following oxygen and glucose deprivation. LDH assay was used to assess viability and Seahorse XF high-resolution respirometry analyzer to investigate post-injury cardiomyocyte bioenergetics. We found no evidence that unconditioned neural stem cell derived exosomes are cardiotoxic nor cardioprotective to H9c2 cardiomyoblasts following ischemia-reperfusion injury. Based on our findings, utilizing unconditioned neural stem cell derived exosomes as post-injury treatment for other organs should not have adverse effects to the damaged cardiac cells.

hBMSC-EVs alleviate weightlessness-induced skeletal muscle atrophy by suppressing oxidative stress and inflammation

BACKGROUND

Muscle disuse and offloading in microgravity are likely the primary factors mediating spaceflight-induced muscle atrophy, for which there is currently no effective treatment other than exercise. Extracellular vesicles derived from bone marrow mesenchymal stem cells (BMSC-EVs) possess anti-inflammatory and antioxidant properties, offering a potential strategy for combating weightless muscular atrophy.

METHODS

In this study, human BMSCs-EVs (hBMSC-EVs) were isolated using super-centrifugation and characterized. C2C12 myotube nutrition-deprivation and mice tail suspension models were established. Subsequently, the diameter of C2C12 myotubes, Soleus mass, cross-sectional area (CSA) of muscle fibers, and grip strength in mice were assessed to investigate the impact of hBMSC-EVs on muscle atrophy. Immunostaining, transmission electron microscopy observation, and western blot analysis were employed to assess the impact of hBMSC-EVs on muscle fiber types, ROS levels, inflammation, ubiquitin-proteasome system activity, and autophagy lysosome pathway activation in skeletal muscle atrophy.

RESULTS

The active hBMSC-EVs can be internalized by C2C12 myotubes and skeletal muscle. hBMSC-EVs can effectively reduce C2C12 myotube atrophy caused by nutritional deprivation, with a concentration of 10 × 108 particles/mL showing the best effect (P < 0.001). Additionally, hBMSC-EVs can down-regulate the protein levels associated with UPS and oxidative stress. Moreover, intravenous administration of hBMSC-EVs at a concentration of 1 × 1010 particles/mL can effectively reverse the reduction in soleus mass (P < 0.001), CSA (P < 0.01), and grip strength (P < 0.001) in mice caused by weightlessness. They demonstrate the ability to inhibit protein degradation mediated by UPS and autophagy lysosome pathway, along with the suppression of oxidative stress and inflammatory responses. Furthermore, hBMSC-EVs impede the transition of slow muscle fibers to fast muscle fibers via upregulation of Sirt1 and PGC-1α protein levels.

CONCLUSIONS

Our findings indicate that hBMSC-EVs are capable of inhibiting excessive activation of the UPS and autophagy lysosome pathway, suppressing oxidative stress and inflammatory response, reversing muscle fiber type transformation, effectively delaying hindlimb unloading-induced muscle atrophy and enhancing muscle function. Our study has further advanced the understanding of the molecular mechanism underlying muscle atrophy in weightlessness and has demonstrated the protective effect of hBMSC-EVs on muscle atrophy.

Emerging roles of extracellular vesicles in oral and maxillofacial areas

The oral and maxillofacial region is a highly complex area composed of multiple tissue types and bears various critical functions of the human body. Diseases in this region pose significant diagnostic and management challenges; therefore, exploring new strategies for early diagnosis, targeted treatment, and tissue reconstruction is key to improving patient prognosis and quality of life. Extracellular vesicles are a group of heterogeneous lipid-bilayer membrane structures secreted by most cell types, including exosomes, microvesicles, and apoptotic bodies. Present in various body fluids and tissues, they act as messengers via the transfer of nucleic acids, proteins, and metabolites to recipient cells. To date, studies have revealed the different roles of extracellular vesicles in physiological or pathological processes, as well as applications in disease diagnosis, prognosis, and treatment. The importance and tissue specificity of the dental and maxillofacial tissues indicate that extracellular vesicles derived from this region are promising for further research. This paper reviews the published data on extracellular vesicles derived from cells, body fluids, and tissues in oral and maxillofacial regions, summarizes the latest advances in extracellular vesicles from extensive sources, and concludes with a focus on the current research progress and application prospects of engineered exosomes in oral science.

Fate and long-lasting therapeutic effects of mesenchymal stromal/stem-like cells: mechanistic insights

A large body of evidence suggests that mesenchymal stromal cells (MSCs) are able to respond rapidly to the cytokine milieu following systemic infusion. This encounter has the potential to dictate their therapeutic efficacy (also referred to as licensing). MSCs are able to rapidly react to cellular damage by migrating to the inflamed tissue and ultimately modifying the inflammatory microenvironment. However, the limited use of MSCs in clinical practice can be attributed to a lack of understanding of the fate of MSCs in patients after administration and long term MSC-derived therapeutic activity. While the known physiological effectors of viable MSCs make a relative contribution, an innate property of MSCs as a therapeutic agent is their caspase-dependent cell death. These mechanisms may be involving the functional reprogramming of myeloid phagocytes via efferocytosis, the process by which apoptotic bodies (ABs) are identified for engulfment by both specialized and non-specialized phagocytic cells. Recent studies have provided evidence that the uptake of ABs with a distinct genetic component can induce changes in gene expression through the process of epigenetic remodeling. This phenomenon, known as 'trained immunity', has a significant impact on immunometabolism processes. It is hypothesized that the diversity of recipient cells within the inflammatory stroma adjacent to MSCs may potentially serve as a biomarker for predicting the clinical outcome of MSC treatment, while also contributing to the variable outcomes observed with MSC-based therapies. Therefore, the long-term reconstructive process of MSCs may potentially be mediated by MSC apoptosis and subsequent phagocyte-mediated efferocytosis.

Umbilical Cord Mesenchymal Stromal Cell-Derived Small Extracellular Vesicles Modulate Skin Matrix Synthesis and Pigmentation

Introduction

Research has unveiled the remarkable properties of extracellular vesicles derived from mesenchymal stromal cells (MSCs), particularly in promoting wound healing, aiding re-epithelialization, revitalizing aging skin, and inhibiting hyperpigmentation. However, investigations into the potential of small extracellular vesicles from umbilical cord-derived MSCs (UC-MSC-sEVs) in reducing scarring and preventing hyperpigmentation remain limited. Therefore, this study aims to evaluate the impact of UC-MSC-sEVs on the synthesis of the skin's extracellular matrix (ECM) and pigmentation using in vitro models.

Methods

The study investigated the impact of characterized UC-MSC-sEVs on various aspects including the proliferation, migration, antioxidant activity, and ECM gene expression of human dermal fibroblasts (HDF). Additionally, the effects of UC-MSC-sEVs on the proliferation, melanin content, and tyrosinase (TYR) activity of human melanoma cells (MNT-1) were examined. Furthermore, ex vivo models were employed to evaluate the skin permeation of PKH26-labelled UC-MSC-sEVs.

Results

The findings indicated that a high concentration of UC-MSC-sEVs positively influenced the proliferation of HDF. However, no changes in cell migration rate were observed. While the expressions of collagen type 1 and type 3 remained unaffected by UC-MSC-sEVs treatment, there were dose-dependent increases in the gene expressions of fibronectin, matrix metallopeptidase (MMP) 1, and MMP 3. Furthermore, UC-MSC-sEVs treatment did not impact the antioxidative superoxide dismutase (SOD) expression in HDF. Although UC-MSC-sEVs did not alter the proliferation of MNT-1 cells, it did result in a dose-dependent reduction in melanin synthesis without affecting TYR activity. However, when it was applied topically, UC-MSC-sEVs failed to penetrate the skin barrier and remained localized within the stratum corneum layer even after 18 hours.

Conclusion

These results highlight the potential of UC-MSC-sEVs in stimulating HDF proliferation, regulating ECM synthesis, and reducing melanin production. This demonstrates the promising application of UC-MSC-sEVs in medical aesthetics for benefits such as scar reduction, skin rejuvenation, and skin lightening.

Dynamic changes of extracellular vesicles during zebrafish organogenesis

Extracellular Vesicles (EVs) play a crucial role in cell differentiation. Despite its role as a well-established vertebrate model, little is known about EVs during zebrafish embryogenesis. This study investigates EVs during zebrafish embryogenesis, analysing size- and concentration-changes over time.Wild-type AB strain zebrafish larvae (zfl) were collected at 24, 48, 72, and 96 h post fertilization (hpf) and homogenized. EVs were isolated and characterized using flow cytometry, negative staining transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and Western Blot.Flow cytometry and TEM showed a high purity of the samples. Small EVs (sEVs) and large EVs (lEVs) were differentiated using NTA, showing that zfl use different types of EVs during embryogenesis. It was observed that the total EV number increased significantly over the first 72 hpf, but not proportionally to zfl growth in length. Additionally, sEV size also increased significantly, with a maximum diameter at 72 hpf. Since most organs are formed during the first 72 hpf and from then on mainly maturation and growth occur, the elevated number and larger size before 72 hpf suggests an important role of EVs during zebrafish organogenesis. Since EVs serve as cargo delivery platforms, the increase in size of sEVs may reflect the need for a higher transport capacity.

Enhanced capture of preeclampsia-derived extracellular vesicles from maternal plasma by monocytes and T lymphocytes

Released from trophoblast and other fetal cells, placental extracellular vesicles (EVs) reach the maternal peripheral blood and modulate immune responses. Increased EVs in plasma of preeclampsia (PE) patients indicate their involvement in the etiology of this condition. This study addresses the uptake of plasma EVs by peripheral blood mononuclear cells (PBMCs) and explores the underlying internalization mechanisms. Plasma EVs were isolated from women with normotensive pregnancy (EVNP) and those with PE (EVPE), and characterized by cryo-transmission electron microscopy, nanoparticle tracking analysis, Western blotting, flow cytometry, and micro bicinchoninic acid assay (micro-BCA). To investigate whether the origin of PBMCs affects uptake, samples from males, pregnant women, and non-pregnant women were included. Primary PBMCs and macrophages derived from the human leukemia monocytic cell line THP-1 were incubated with PKH-stained EVs, and uptake was assessed by flow cytometry and confocal microscopy. Key molecules involved in monocyte differentiation and macrophage function were evaluated in EV-treated cells using LEGENDplex™ assay and real-time polymerase chain reaction (RT-PCR). Independent of the PBMC source, EVs were mostly captured by monocytes and in a lower proportion by T lymphocytes. Capture of EVPE was higher than of EVNP in primary T lymphocytes, monocytes, and THP-1-derived macrophages. After inhibition by Wortmannin and Cytochalasin D, EV internalization by THP-1-derived macrophages was significantly inhibited but not completely abolished. No defined polarization profile of treated THP-1-derived macrophages could be identified. These findings provide evidence of EV modifications in PE, which enhance their uptake by monocytes and other immune cells, mainly through phagocytosis and endocytosis.

The Effects of Hypoxia-Preconditioned Dental Stem Cell-Derived Secretome on Tissue Regeneration

Mesenchymal stroma cells derived from oral tissues are known as dental stem cells (DSCs). Owing to their unique therapeutic niche and clinical accessibility, DSCs serve as a promising treatment option for bone defects and oral tissue regeneration. DSCs exist in a hypoxic microenvironment in vivo, which is far lower than the current 20% oxygen concentration used in in vitro culture. It has been widely reported that the application of an oxygen concentration less than 5% in the culture of DSCs is beneficial for preserving stemness and promoting proliferation, migration, and paracrine activity. The paracrine function of DSCs involves the secretome, which includes conditioned media (CM) and soluble bioactive molecules, as well as extracellular vesicles extracted from CM. Hypoxia can play a role in immunomodulation and angiogenesis by altering the protein or nucleic acid components in the secretory group, which enhances the therapeutic potential of DSCs. This review summarizes the biological characteristics of DSCs, the influence of hypoxia on DSCs, the impact of hypoxia on the secretory group of DSCs, and the latest progress on the use of DSCs secretory group in tissue regeneration based on hypoxia pretreatment. We highlighted the multifunctional biological effect of hypoxia culture on tissue regeneration and provided a summary of the current mechanism of hypoxia in the pretreatment of DSCs.

Protective Effect and Molecular Mechanism of Mesenchymal Stem Cell-Derived Extracellular Vesicles in Diabetic Foot Ulcers

This study explores the protective mechanism of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) in diabetic foot ulcer (DFU). Human umbilical cord MSCs (HucMSCs) were identified via osteogenesis and adipogenic differentiation, as well as flow cytometry. EVs were isolated from HucMSCs and characterized using transmission electron microscopy, nanoparticle tracking analysis, and Western blotting. Fluorescence microscopy revealed the uptake of PKH67-labeled EVs and Cy3-labeled microRNA-21-5p (miR-21-5p) by human skin fibroblasts (HSFs). EVs were cocultured with HSFs, and cell proliferation and migration were assessed using Cell Counting Kit-8, colony formation, scratch, and Transwell assays. miR-21-5p overexpression in EVs was evaluated for its role in promoting HSF functions. The expression levels of miR-21-5p, Krüppel-like factor 6 (KLF6), α-smooth muscle actin, and collagen type I alpha 1 chain were analyzed via quantitative real-time PCR and Western blotting. The interaction between miR-21-5p and KLF6 was confirmed through a dual-luciferase reporter gene assay. HucMSC-derived EVs enhanced the proliferation and migration of HSFs under high glucose by delivering miR-21-5p, which targeted and inhibited KLF6. Overexpression of KLF6 counteracted the pro-proliferative and migratory effects of EVs carrying miR-21-5p. Overall, these findings suggest that HucMSC-EVs promote HSF proliferation and migration by downregulating KLF6 via miR-21-5p delivery, offering a potential therapeutic strategy for DFU.

Recent Advances in Microfluidics for Nucleic Acid Analysis of Small Extracellular Vesicles in Cancer

Small extracellular vesicles (sEVs) are membranous vesicles released from cellular structures through plasma membrane budding. These vesicles contain cellular components such as proteins, lipids, mRNAs, microRNAs, long-noncoding RNA, circular RNA, and double-stranded DNA, originating from the cells they are shed from. Ranging in size from ≈25 to 300 nm and play critical roles in facilitating cell-to-cell communication by transporting signaling molecules. The discovery of sEVs in bodily fluids and their involvement in intercellular communication has revolutionized the fields of diagnosis, prognosis, and treatment, particularly in diseases like cancer. Conventional methods for isolating and analyzing sEVs, particularly their nucleic acid content face challenges including high costs, low purity, time-consuming processes, limited standardization, and inconsistent yield. The development of microfluidic devices, enables improved precision in sorting, isolating, and molecular-level separation using small sample volumes, and offers significant potential for the enhanced detection and monitoring of sEVs associated with cancer. These advanced techniques hold great promise for creating next-generation diagnostic and prognostic tools given their possibility of being cost-effective, simple to operate, etc. This comprehensive review explores the current state of research on microfluidic devices for the detection of sEV-derived nucleic acids as biomarkers and their translation into practical point-of-care and clinical applications.

Stimulatory Effect of Mammalian Exosomes on Intradermal Fibroblast Proliferation

BACKGROUND

This study investigates the potential of extracellular vesicles (EVs) in skin regeneration and rejuvenation. EVs, nanoscale vesicles released by various cell types, play a crucial role in intercellular communication.

OBJECTIVE

To reaffirm the pivotal role of blood-derived exosomes in intercellular communication and their potential for skin tissue regeneration, leveraging existing research, including human data, to advocate for exosomes as a viable cell-free therapy for skin health.

METHODS

The study employs a novel isolation technique combining PEG and Dextran with ultracentrifugation to extract EVs from plasma. Characterization techniques, including NTA, AFM, Cryo-TEM, and FC, confirm the successful isolation and characterization of EVs.

RESULTS

The study demonstrates positive effects of blood-derived EVs on fibroblast proliferation, collagen, and elastin production in murine and human models. Despite advancements, challenges persist in obtaining consistent EVs quality and concentration. The findings support the clinical relevance of EVs in skin health and suggest potential applications for skin rejuvenation. Future research directions and study limitations are also discussed, contributing to the evolving understanding of EVs-based therapies.

Brain-targeting drug delivery systems: The state of the art in treatment of glioblastoma

Glioblastoma (GBM) is the most prevalent primary malignant brain tumor, characterized by a high mortality rate and a poor prognosis. The blood-brain barrier (BBB) and the blood-tumor barrier (BTB) present significant obstacles to the efficacy of tumor-targeted pharmacotherapy, thereby impeding the therapeutic potential of numerous candidate drugs. Targeting delivery of adequate doses of drug across the BBB to treat GBM has become a prominent research area in recent years. This emphasis has driven the exploration and evaluation of diverse technologies for GBM pharmacotherapy, with some already undergoing clinical trials. This review provides a thorough overview of recent advancements and challenges in targeted drug delivery for GBM treatment. It specifically emphasizes systemic drug administration strategies to assess their potential and limitations in GBM treatment. Furthermore, this review highlights promising future research directions in the development of intelligent drug delivery systems aimed at overcoming current challenges and enhancing therapeutic efficacy against GBM. These advancements not only support foundational research on targeted drug delivery systems for GBM but also offer methodological approaches for future clinical applications.

Acidity and hypoxia of tumor microenvironment, a positive interplay in extracellular vesicle release by tumor cells

The complex and continuously evolving features of the tumor microenvironment, varying between tumor histotypes, are characterized by the presence of host cells and tumor cells embedded in a milieu shaped by hypoxia and low pH, resulting from the frequent imbalance between vascularity and tumor cell proliferation. These microenvironmental metabolic stressors play a crucial role in remodeling host cells and tumor cells, contributing to the stimulation of cancer cell heterogeneity, clonal evolution, and multidrug resistance, ultimately leading to progression and metastasis. The extracellular vesicles (EVs), membrane-enclosed structures released into the extracellular milieu by tumor/host cells, are now recognized as critical drivers in the complex intercellular communication between tumor cells and the local cellular components in a hypoxic/acidic microenvironment. Understanding the intricate molecular mechanisms governing the interactions between tumor and host cells within a hypoxic and acidic microenvironment, triggered by the release of EVs, could pave the way for innovative strategies to disrupt the complex interplay of cancer cells with their microenvironment. This approach may contribute to the development of an efficient and safe therapeutic strategy to combat cancer progression. Therefore, we review the major findings on the release of EVs in a hypoxic/acidic tumor microenvironment to appreciate their role in tumor progression toward metastatic disease.

Extracellular vesicles released by ALL patients contain HNE-adducted proteins: Implications of collateral damage

Off-target neuronal injury is a serious side-effect observed in cancer survivors. It has previously been shown that pediatric acute lymphoblastic leukemia (ALL) survivors have a decline in neurocognition compared to healthy age-matched counterparts. Elevated oxidative stress has been documented to be a mediator in off-target tissue damage in cancer survivors. Early detection of oxidative stress markers may provide an opportunity to prevent off-target tissue damage. Extracellular vesicles (EVs) have surfaced as a potential diagnostic tool due to molecular cargo they contain. We investigated the potential for EVs to be a sensitive indicator of oxidative stress and off-target tissue damage by isolating EVs from pediatric ALL patients throughout their first 2 months of treatment. EVs were measured throughout the collection points for: 1) number of EV particles generated using nanoparticle tracking analysis (NTA); 2) markers of neurons (NeuN), astrocyte activation (GFAP), neuronal stability (BDNF), 3) markers of pre-B cell ALL (CD19 and CD22); and) 4-hydroxy-2-nonenal (HNE) adducted proteins. HNE protein adductions were measured in the patient sera and CSF. Pro-inflammatory cytokine levels were also measured in patient sera because of their contribution to oxidative stress and neuronal injury. Our results: 1) demonstrate EVs are a sensitive indicator of oxidative damage; 2) suggest EVs as a marker of a decline in neuronal stability; and 3) show the presence of leukemia has a greater contribution to pro-inflammatory cytokine production in the patient's serum than the cancer treatment. Specifically, we observed a significant decrease in cytokine levels (e.g., TNF-α, IL-1β, IL-6, and IL-8) following the initiation of treatment, highlighting the influence of leukemia burden on systemic inflammation. The results support the utilization of EVs as a sensitive marker of oxidative stress and off-target tissue damage.

Inhibition of Small Extracellular Vesicles by GW4869 Does not Disrupt the Paracrine Regulation of Adipose-Derived Mesenchymal Stem Cells Over Keloid Fibroblasts

BACKGROUND

Keloid, scar caused by atypical wound repair, represents a significant difficulty for specialists in plastic surgery and dermatology. Adipose-derived mesenchymal stem cells (ADSCs) can regulate fibrotic phenotypes of keloid fibroblasts (KFs) in a paracrine fashion, but whether small extracellular vesicles (SEVs) are the key functional carrier in ADSC paracrine regulation of KFs remains unknown. This study aims to explore whether the regulatory effects of conditioned medium (CM) obtained from ADSCs on KFs can be impaired by decreased SEV content in the ADSC-CM.

METHODS

Clinical specimens were utilized to extract keloid fibroblasts (KFs), normal fibroblasts (NFs), and adipose-derived stem cells (ADSCs). Fibroblasts were cultured with CM obtained from ADSCs untreated or treated with the sphingomyelinase inhibitor GW4869. The features of SEVs derived from ADSC-CM were characterized, and fibroblast proliferation, migration, apoptosis, and expression of ECM proteins were analyzed.

RESULTS

The sphingomyelinase inhibitor GW4869 successfully reduced the SEV content in ADSC-CM, and both control ADSC-CM and ADSC-CM with reduced SEV content significantly inhibited KF proliferation, migration, and α-SMA synthesis but not KF apoptosis, whereas only NF proliferation was inhibited by ADSC-CM. The reduced SEV content only affected the inhibition of KF proliferation induced by ADSC-CM.

CONCLUSION

ADSC-CM inhibits various fibrotic phenotypes of KFs, but decreasing the SEV content in ADSC-CM did not significantly alter the antifibrotic effects of ADSC-CM. Thus, SEVs may not be the key mediator of ADSCs paracrine regulation of KFs.

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Isolation, identification, and challenges of extracellular vesicles: emerging players in clinical applications

Extracellular vesicles (EVs) serve as critical mediators of intercellular communication, encompassing exosomes, microvesicles, and apoptotic vesicles that play significant roles in diverse physiological and pathological contexts. Numerous studies have demonstrated that EVs derived from mesenchymal stem cells (MSC-EVs) play a pivotal role in facilitating tissue and organ repair, alleviating inflammation and apoptosis, enhancing the proliferation of endogenous stem cells within tissues and organs, and modulating immune function-these functions have been extensively utilized in clinical applications. The precise classification, isolation, and identification of MSC-EVs are essential for their clinical applications. This article provides a comprehensive overview of the biological properties of EVs, emphasizing both their advantages and limitations in isolation and identification methodologies. Additionally, we summarize the protein markers associated with MSC-EVs, emphasizing their significance in the treatment of various diseases. Finally, this article addresses the current challenges and dilemmas in developing clinical applications for MSC-EVs, aiming to offer valuable insights for future research.

Extracellular vesicle-packed microRNAs profiling in Alzheimer's disease: The molecular intermediary between pathology and diagnosis

MicroRNAs (miRNAs), referring to a type of non-coding RNAs functioning in various biological processes, participate in the pathophysiology of Alzheimer's disease (AD) through increasing amyloid-beta (Aβ) production, enhancing Tau phosphorylation, and inducing neuroinflammation. Meanwhile, extracellular vesicles (EVs) have been suggested as promising carriers of AD biomarkers as they possess the ability to transmit information from cerebral tissue to peripheral blood. Inspired by the above findings, we in this review systematically generalized the roles of miRNAs in AD and explored the potential of EV-packed miRNA as biomarkers for early diagnosis of AD. Through the detailed investigation, this review may highlight the promise of EV-packed miRNAs in advancing our understanding of AD, and underscore the imperative needs of further studies on their diagnostic potential.

Establishment of an experimental system to analyse extracellular vesicles during apoplastic fungal pathogenesis

Phoma stem canker disease of oilseed rape (Brassica napus) is caused by the extracellular fungal pathogen Leptosphaeria maculans. Although this pathogen resides exclusively in apoplastic spaces surrounding plant cells, the significance of extracellular vesicles (EVs) has not been assessed. Here, we show a method to collect apoplastic fluids (AFs) from infected leaves or cotyledons for collection of EVs during the process of host colonisation. The 15,000 × g supernatants of AFs were shown to contain ribulose-bisphosphate carboxylase (RuBisCO) at 7 days post-inoculation with L. maculans, a protein that was absent from unchallenged cotyledons. RuBisCO release coincided with the switch from biotrophy to necrotrophy, suggesting the involvement of host cell death. However, RuBisCO release did not differ between compatible and incompatible interactions, suggesting necrotrophic host cell death might not be the only process involved. EVs were also collected from axenic fungal cultures and characterised for their particle size distribution using nanoparticle tracking analysis and transmission electron microscopy. The protein composition of EV-enriched fractions was analysed using SDS-PAGE and proteomics. Enrichment analysis of gene ontology terms provided evidence for involvement of glucan and chitin metabolism as well as catalase and peptidase activities. Most of the proteins identified have previously been found in EV studies and/or EV databases, and for most of the proteins evidence was found for an involvement in pathogenicity/virulence.

MicroRNA in neuroexosome as a potential biomarker for HIV-associated neurocognitive disorders

HIV-associated neurocognitive disorder (HAND) is a complication of chronic inflammation caused by HIV infection that impairs cognitive and motor functions. HAND can occur at any age, regardless of the duration of infection, even in people living with HIV (PLWH) whose blood viral load is controlled by antiretroviral therapy. The diagnosis of HAND requires a battery of neuropsychological tests, which is time-consuming and burdensome, limiting its effectiveness for screening PLWH. Here, we aimed to identify biomarkers for quantitatively diagnosing and screening for HAND using minimally invasive blood tests. Neuronal-derived exosomes (neuroexosomes) were isolated from the peripheral blood of PLWH, and the transcriptomes of their microRNAs (miRNAs) were analyzed. We identified five upregulated miRNAs (hsa-miR-16-5p, hsa-miR-26a-3p, hsa-92a-3p, hsa-miR-103a-3p, and hsa-miR-185-5p), and two downregulated miRNA (hsa-miR-3613-3p and hsa-miR-4668-5p) in PLWH diagnosed with HAND (HAND PLWH). Functional analysis of five miRNAs whose expression levels increased in HAND PLWH using the database showed that these miRNAs are involved in motor proteins and endocytosis, which are associated with nerve function. The expression levels of hsa-miR-16-5p, hsa-miR-103a-3p, and hsa-miR-185-5p were significantly higher than those in the non-HIV controls and non-HAND PLWH, suggesting that these miRNAs are potential biomarkers for HAND. Since there were no changes in known dementia miRNA biomarkers in HAND PLWH, the miRNAs identified in this study will allow for early differentiation of HAND.

Small Extracellular Vesicles Engineered Using Click Chemistry to Express Chimeric Antigen Receptors Show Enhanced Efficacy in Acute Liver Failure

Acetaminophen (APAP) overdose can cause severe liver injury and life-threatening conditions that may lead to multiple organ failure without proper treatment. N-acetylcysteine (NAC) is the accepted and prescribed treatment for detoxification in cases of APAP overdose. Nonetheless, in acute liver failure (ALF), particularly when the ingestion is substantial, NAC may not fully restore liver function. NAC administration in ALF has limitations and potential adverse effects, including nausea, vomiting, diarrhoea, flatus, gastroesophageal reflux, and anaphylactoid reactions. Mesenchymal stromal cell (MSC)-based therapies using paracrine activity show promise for treating ALF, with preclinical studies demonstrating improvement. Recently, MSC-derived extracellular vesicles (EVs) have emerged as a new therapeutic option for liver injury. MSC-derived EVs can contain various therapeutic cargos depending on the cell of origin, participate in physiological processes, and respond to abnormalities. However, most therapeutic EVs lack a distinct orientation upon entering the body, resulting in a lack of targeting specificity. Therefore, enhancing the precision of natural EV delivery systems is urgently needed. Thus, we developed an advanced targeting technique to deliver modified EVs within the body. Our strategy aims to employ bioorthogonal click chemistry to attach a targeting molecule to the surface of small extracellular vesicles (sEVs), creating exogenous chimeric antigen receptor-modified sEVs (CAR-sEVs) for the treatment. First, we engineered azido-modified sEVs (N3-sEVs) through metabolic glycoengineering by treating MSCs with the azide-containing monosaccharide N-azidoacetyl-mannosamine (Ac4ManNAz). Next, we conjugated N3-sEVs with a dibenzocyclooctyne (DBCO)-tagged single-chain variable fragment (DBCO-scFv) that targets the asialoglycoprotein receptor (ASGR1), thus producing CAR-sEVs for precise liver targeting. The efficacy of CAR-sEV therapy in ALF models by targeting ASGR1 was validated. MSC-derived CAR-sEVs reduced serum liver enzymes, mitigated liver damage, and promoted hepatocyte proliferation in APAP-induced injury. Overall, CAR-sEVs exhibited enhanced hepatocyte specificity and efficacy in ameliorating liver injury, highlighting the significant advancements achievable with cell-free targeted therapy.

Immune evasion through mitochondrial transfer in the tumour microenvironment

Cancer cells in the tumour microenvironment use various mechanisms to evade the immune system, particularly T cell attack1. For example, metabolic reprogramming in the tumour microenvironment and mitochondrial dysfunction in tumour-infiltrating lymphocytes (TILs) impair antitumour immune responses2-4. However, detailed mechanisms of such processes remain unclear. Here we analyse clinical specimens and identify mitochondrial DNA (mtDNA) mutations in TILs that are shared with cancer cells. Moreover, mitochondria with mtDNA mutations from cancer cells are able to transfer to TILs. Typically, mitochondria in TILs readily undergo mitophagy through reactive oxygen species. However, mitochondria transferred from cancer cells do not undergo mitophagy, which we find is due to mitophagy-inhibitory molecules. These molecules attach to mitochondria and together are transferred to TILs, which results in homoplasmic replacement. T cells that acquire mtDNA mutations from cancer cells exhibit metabolic abnormalities and senescence, with defects in effector functions and memory formation. This in turn leads to impaired antitumour immunity both in vitro and in vivo. Accordingly, the presence of an mtDNA mutation in tumour tissue is a poor prognostic factor for immune checkpoint inhibitors in patients with melanoma or non-small-cell lung cancer. These findings reveal a previously unknown mechanism of cancer immune evasion through mitochondrial transfer and can contribute to the development of future cancer immunotherapies.

Comparison of Methods for Isolation and Characterization of Total and Astrocyte-Enriched Extracellular Vesicles From Human Serum and Plasma

Extracellular vesicles (EV) which play critical roles in intercellular communication, have garnered interest as biomarkers with researchers studying brain-related disease processes due to their ability to be isolated from various biofluids. Astrocytes, a type of glial cell, play a critical role in neuronal regulation and function. As such, EV enriched from astrocytes can be used to interrogate cargo and identify mechanisms by which astrocytes communicate with other cells of the central nervous system or shed light on pathophysiological conditions. This manuscript compared five EV isolation methods (differential ultracentrifugation [dUC], precipitation, precipitation + purification, silicon carbon resin and size exclusion chromatography [SEC]) using small volumes of human plasma and serum with a focus on immunocapture of astrocyte-enriched EV (AEEV), with the excitatory amino acid transporter 1, or GLAST. Methods were evaluated on yield, purity, recovery and downstream application to include immunoassays for tetraspanin, immune and astrocyte markers. Results revealed that whilst precipitation-based methods such as ExoQuick yielded higher EV concentrations, size exclusion (SmartSEC, qEV) provided greater purity, emphasizing a trade-off between yield and purity. This study provides a comprehensive resource for researchers in selecting EV isolation methods tailored to small biobanked clinical samples, with the goal of advancing biomarker discovery in Neuroscience.

Metabolic Profiling of Brain Tissue and Brain-Derived Extracellular Vesicles in Alzheimer's Disease

Alzheimer´s disease (AD) is the most frequent neurodegenerative disorder in the world and is characterised by the loss of memory and other cognitive functions. Metabolic changes associated with AD are important players in the development of the disease. However, the mechanism underlying these changes is still unknown. Extracellular vesicles (EVs) are nano-sized particles that play an important role in regulating pathophysiological processes and are a non-invasive manner to obtain information of the cell that is secreting them. The analysis of brain-derived EVs (bdEVs) will provide new insights in the metabolic processes associated with AD. To characterize bdEVs in AD, we optimised a method to isolate them from tissue of different brain regions, obtaining the highest enrichment in isolations from the temporal cortex. We performed unbiased untargeted metabolomics analysis on post-mortem human temporal cortex tissue and bdEVs from the same region of AD patients and healthy controls. Both, univariate and multivariate statistical analysis were used to determine the metabolites that influence the separation between AD patients and controls. Interestingly, a clear separation between control and AD groups was obtained with bdEVs, which allowed to select 12 relevant features by a validated PLS-DA model. Furthermore, comparison of tissue and bdEVs identified 68 common features. The pathway enrichment analysis of the common metabolites showed that the alanine, aspartate and glutamate pathway and the arginine, phenylalanine, tyrosine pathway were the most significant ones in the separation between the AD patients and controls. The phenylalanine, tyrosine and tryptophan pathway, still had a very high influence in the separation between groups, albeit not significant. Notably, some metabolites were identified for the first time in bdEVs. For example, the N-acetyl aspartic acid (NAA) metabolite present in bdEVs was suitable to differentiate AD patients from healthy controls. Furthermore, the analysis of the hippocampus, midbrain, temporal and entorhinal cortex and their respective bdEVs indicated that the metabolic profiles of different brain areas were distinct and showed some correlation between the metabolome of the tissue and its respective bdEVs. Thus, our study highlights the potential of bdEVs to understand the metabolic fingerprint associated with AD and their potential use as diagnostic and therapeutic targets.