Extracellular Vesicles Subpopulations Research Articles

PATH-10. UTILIZATION OF TUMOR-DERIVED EXTRACELLULAR VESICLES FOR PATIENT STRATIFICATION AND BIOMARKER DISCOVERY

Abstract Liquid biopsy is poised to play an increasingly important role in clinical decision making by enabling earlier cancer detection, diagnosis, patient stratification, and treatment monitoring. Most approaches rely on detection of cell-free circulating tumor DNA or circulating tumor cells in the peripheral blood of cancer patients. However, there are several limitations to these approaches, including miniscule abundance, unfavorable signal to noise ratios, and limited insight into mechanisms driving disease. Extracellular vesicles (EVs) are an alternative liquid biopsy analyte comprising lipid membrane encapsulated particles carrying diverse protein, nucleic acid, and metabolite cargos. Blood plasma of cancer patients contains EVs derived directly from tumor tissue that serve as rich sources of insight into tumor biology and disease pathology. We have developed a clinically applicable, multi-omic EV subpopulation interrogation pipeline that robustly profiles tumor-derived EVs in biofluids. We have demonstrated the ability of the platform to enrich cancer markers and detect activation of pathways driving oncogenesis across several different cancers, including brain cancer. There is a particularly compelling need for liquid biopsy-based solutions in neuro-oncology. We have applied our EV-omic (EVO) pipeline in combination with machine learning to distinguish adult high-grade gliomas from benign brain tumor and healthy patients, using blood-based EV proteomic and transcriptomic signatures. Marker profiles found to be most important for patient stratification combine markers known to be relevant in tumor tissue along with novel features. Furthermore, IDH status and MGMT methylation metadata derived from matched patient tissue for select cases was used to generate unique blood-based profiles for glioma subtypes. Lastly, we show preliminary longitudinal data demonstrating the utility of EVs to track tumor changes post-surgical resection and post-treatment. This work demonstrates that EV-omics can add significant value in the neuro-oncology space.

A Reproducible Protocol for the Isolation of Malaria-Derived Extracellular Vesicles by Differential Centrifugation

Over the last few decades, malaria-derived extracellular vesicles (EVs) have gained increasing interest due to their role in disease pathophysiology and parasite biology. Unlike other EV research fields, the isolation of malaria EVs is not standardized, hampering inter-study comparisons. Most malaria EV studies isolate vesicles by the “gold-standard” technique of differential (ultra)centrifugation (DC). Here, we describe in detail an optimized and reproducible protocol for the isolation of malaria-derived EVs by DC. The protocol begins with a description of cultivating high-parasitemia, synchronous P. falciparum cultures that are the source of EV-containing conditioned culture media. The isolation protocol generates two EV subtypes, and we provide details of characterizing these distinct subtypes by analyzing human and parasite proteins by Western blot analysis. We identify some of these proteins as suitable markers for malaria EV subpopulations and subtypes.

Tracking the uptake of labelled host-derived extracellular vesicles by the human fungal pathogen Aspergillus fumigatus

Abstract Extracellular vesicles (EVs) have gained attention as facilitators of intercellular as well as interkingdom communication during host-microbe interactions. Recently we showed that upon infection, host polymorphonuclear leukocytes produce antifungal EVs targeting the clinically important fungal pathogen Aspergillus fumigatus; however, the small size of EVs (< 1 µm) complicates their functional analysis. Here, we employed a more tractable, reporter-based system to label host alveolar epithelial cell-derived EVs and enabled their visualisation during in vitro A. fumigatus interaction. Fusion of EV marker proteins (CD63, CD9, and CD81) with a Nanoluciferase (NLuc) and a green fluorescent protein (GFP) facilitated their relative quantification by luminescence and visualization by a fluorescence signal. The use of an NLuc fused with a GFP is advantageous as it allows for quantification and visualisation of EVs simultaneously without additional external manipulation and to distinguish subpopulations of EVs. Using this system, visualisation and tracking of EVs was possible using confocal laser scanning microscopy and advanced imaging analysis. These experiments revealed the propensity of host cell-derived EVs to associate with the fungal cell wall and ultimately colocalize with the cell membrane of A. fumigatus hyphae in large numbers. In conclusion, we have created a series of tools to better define the complex interplay of host-derived EVs with microbial pathogens.

Extracellular vesicles characterization in patients with hypertrophic cardiomyopathy

Abstract Background Hypertrophic cardiomyopathy (HCM) is a genetic disorder, diagnosed according to the presence of phenotypical traits of the myocardium. A specific biomarker which can associate with the severity of HCM is lacking. Extracellular Vesicles (EVs), nanoparticles released by cells into biological fluids, hold promise as accessible diagnostic tools, as their abundance and molecular composition can reflect the severity of cardiac diseases (Rizzuto 2024). We aim at characterising plasma-derived EVs isolated from 28 HCM patients and 18 healthy volunteers (CTR). Methods The whole cohort underwent transthoracic echocardiography, whereas magnetic resonance and exome sequencing was performed on HCM patients. EVs were isolated via ultracentrifugation from plasma of both groups. Quantitative and qualitative assessments of EVs were performed by nanoparticle tracking analysis, transmission electron microscopy, Western blot, targeted (Olink) and untargeted (nLC-MS/MS) proteomics and FACS analysis. Plasma-derived EV subpopulations were characterised according to their cellular origin. Data are expressed as median and interquartile range (25th, 75th). Results Most patients were male (68% HCM and 66% CTR) with a median age of 58 (49-69) years (HCM) and 47 (44-52) (CTR). Among HCM patients, missense mutations in the MYH7 gene were the most identified. The median maximum wall thickness (WTMax) in HCM was 16 mm (15-19) vs 8 mm (7-9) in CTR. The isolated EVs expressed tetraspanins (CD9, CD63 and CD81), Alix and β-integrin and showed an intact phospholipid bilayer of 100 nm in size. EV concentration was reduced in HCM vs CTRL, respectively 2.8*109 EV/ml/cell count (2*109-4*109) and 4.6*10⁹ EV/ml/cell count (3*109-6*109). Among 15 plasma-derived EV subpopulations studied, those released from platelets (CD41a) and activated platelets (CD62P and CD40L) were increased in HCM patients vs CTR by 1.7 fold. Negative associations were found between E/e’, parameter of diastolic function, and cardiomyocyte-derived EVs (r= -0.2658), and between left ventricle ejection fraction and platelet-derived EVs (r=-0.2189); a positive correlation was found between WTMax and EVs derived from activated endothelial cells (r=0.2330). The proteomic analysis of EVs shows an enrichment in proteins related to platelets adhesion and inflammation in HCM patients. Conclusions HCM patients present a peculiar phenotypic pattern of EVs that may associate with diagnostic clinical features of HCM.

Secretion correlation between matrix metalloproteinases and extracellular vesicles revealed by synchronized dynamic monitoring of single cells on a microfluidic chip

Despite growing interest in matrix metalloproteinases (MMPs) as promising therapeutic targets for cancer treatments, cellular trafficking and release of MMPs remain underexplored. To evaluate to what content the MMP secretion is associated with extracellular vesicles (EVs), in this study, we report a droplet microfluidic assay for simultaneous dynamic monitoring of the MMP and EV secretion at the single-cell level. Microdroplets containing single cells were generated in a flow-focusing microchannel and then guided to a microcolumn array for on-chip patterning, incubation and time-lapse microscopy. Utilizing a green fluorescent substrate for MMP activity and a red fluorescent protein reporter for EVs, temporal secretion dynamics of MMPs and EVs from individual cells were recorded respectively. With this dual-reporter system, a strong correlation between MMP and EV secretion was revealed. We further demonstrated that promotion or inhibition of EV release by altering intracellular calcium levels would induce a rise or fall in single-cell MMP secretion, which was masked by population-based experiments. More importantly, the activated release of this EV subpopulation (exosomes) also resulted in a higher correlation coefficient between MMP and EV secretion, and vice versa. Therefore, compared to other EV subpopulations, exosomes should be more closely connected with MMP secretion, and thus may represent a potential target for combination therapy. When in contrast with bulk experiments, single-cell analysis of the secretion correlation between MMPs and EVs not only reveals extensive cellular heterogeneity, but also exhibits a higher resolution.

Rivaroxaban, in combination with low-dose aspirin, is associated with a reduction in proinflammatory and prothrombotic circulating vesicle signatures in patients with cardiovascular disease

BackgroundDespite secondary prevention with aspirin, patients with stable cardiovascular disease (CVD) remain at elevated long-term risk of major adverse cardiovascular events. The Cardiovascular Outcomes in People Using Anticoagulant Strategies (COMPASS) double-blind, randomized clinical trial demonstrated that aspirin plus low-dose rivaroxaban (COMPASS regime) significantly decreased the incidence of major adverse cardiovascular events by 24% compared with aspirin alone. However, the mechanisms underlying these potential synergistic/nonantithrombotic effects remain elusive. Extracellular vesicles (EVs) are crucial messengers regulating a myriad of biological/pathological processes and are highly implicated in CVD. ObjectivesWe hypothesized that circulating EV profiles reflect the cardioprotective properties of the COMPASS regime. MethodsA cohort of stable CVD patients (N = 40) who participated in the COMPASS trial and were previously randomized to receive aspirin were prospectively recruited and assigned a revised regimen of open-label aspirin plus rivaroxaban. Blood samples were obtained at baseline (aspirin only) and 6-month follow-up. Plasma EV concentration, size, and origin were analyzed by nanoparticle tracking analysis and flow cytometry. EVs were enriched by ultracentrifugation for proteomic analysis. ResultsThe COMPASS regime fundamentally altered small (<200 nm) and large (200-1000 nm) EV concentration and size compared with aspirin alone. Crucially, levels of platelet-derived and myeloperoxidase-positive EVs became significantly decreased at follow-up. Comparative proteomic characterization further revealed a significant decrease in highly proinflammatory protein expression at follow-up. ConclusionThe observed changes in EV subpopulations, together with the differential protein expression profiles, suggest amelioration of an underlying proinflammatory and prothrombotic state upon dual therapy, which may be of clinical relevance toward understanding the fundamental mechanism underlying the reported superior cardiovascular outcomes associated with this antithrombotic regimen.

Isolation of CD63-positive epididymosomes from human semen and its application in improving sperm function.

Extracellular vesicles (EVs) are highly heterogeneous, and different EV subpopulations from various origins mediate different biological effects. The separation of different subpopulations of EVs from mixtures is critical but challenging. Epididymosomes are secreted by the epididymal epithelium and play a key role in sperm maturation and function. However, limited access to human epididymal tissue and epididymal fluid has hampered further study of epididymosomes and their potential clinical applications. Here, we established a novel strategy based on flow cytometry sorting to isolate human CD63-positive epididymosomes from ejaculate. We identified CD52, a membrane-located protein expressed exclusively in the epididymis, as the sorting marker for human epididymosomes. Then, CD63-positive epididymosomes were isolated from human semen using a flow cytometry sorting instrument and concentrated. Additionally, we observed that isolated CD63-positive epididymosomes improved sperm function more than other CD63-positive seminal EV subpopulations did, demonstrating the successful isolation of a subpopulation of epididymosomes from human semen and their potential application in the clinic.

A critical systematic review of extracellular vesicle clinical trials.

This systematic review examines the landscape of extracellular vesicle (EV)-related clinical trials to elucidate the field's trends in clinical applications and EV-related methodologies, with an additional focus on the acknowledgement of EV subpopulations. By analysing data from public reporting repositories, we catalogued 471 EV-related clinical trials to date, with indications for over 200 diseases. Diagnostics and companion diagnostics represented the bulk of EV-related clinical trials with cancer being the most frequent application. EV-related therapeutics trials mainly utilized mesenchymal stromal cell (MSC) EVs and were most frequently used for treatment of respiratory illnesses. Ultracentrifugation and RNA-sequencing were the most common isolation and characterization techniques; however, methodology for each was not frequently reported in study records. Most of the reported characterization relied on bulk characterization of EV isolates, with only 11% utilizing EV subpopulations in their experimental design. While this may be connected to a lack of available techniques suitable for clinical implementation, it also highlights the opportunity for use of EV subpopulations to improve translational efforts. As academic research identifies more chemically distinct subpopulations and technologies for their enrichment, we forecast to more refined EV trials in the near future. This review emphasizes the need for meticulous methodological reporting and consideration of EV subpopulations to enhance the translational success of EV-based interventions, pointing towards a paradigm shift in personalized medicine.

Integrin α6-containing extracellular vesicles promote lymphatic remodelling for pre-metastatic niche formation in lymph nodes via interplay with CD151.

Heterogeneous extracellular vesicles (EVs) from various types of tumours are acknowledged for inducing the formation of pre-metastatic "niches" in draining lymph nodes (LNs) to promote lymphatic metastasis. In order to identify the specific subpopulations of EVs involved, we performed high-resolution proteomic analysis combined with nanoflow cytometry of bladder cancer (BCa) tissue-derived EVs to identify a novel subset of tumour-derived EVs that contain integrin α6 (ITGA6+EVs) and revealed the positive correlation of ITGA6+EVs with the formation of pre-metastatic niche in draining LNs and lymphatic metastasis in multicentre clinical analysis of 820-case BCa patients. BCa-derived ITGA6+EVs induced E-selectin (SELE)-marked lymphatic remodelling pre-metastatic niche and promoted metastasis in draining LNs through delivering cargo circRNA-LIPAR to lymphatic endothelial cells in vivo and in vitro. Mechanistically, LIPAR linked ITGA6 to the switch II domain of RAB5A and sustained RAB5A GTP-bound activated state, thus maintaining the production of ITGA6+EVs loaded with LIPAR through endosomal trafficking. ITGA6+EVs targeted lymphatic vessels through ITGA6-CD151 interplay and released LIPAR to induce SELE overexpression-marked lymphatic remodelling pre-metastatic niche. Importantly, we constructed engineered-ITGA6 EVs to inhibit lymphatic pre-metastatic niche, which suppressed lymphatic metastasis and prolonged survival in preclinical models. Collectively, our study uncovers the mechanism of BCa-derived ITGA6+EVs mediating pre-metastatic niche and provides an engineered-EV-based strategy against BCa lymphatic metastasis.

Landscape of exosomes to modified exosomes: a state of the art in cancer therapy.

Exosomes are a subpopulation of extracellular vesicles (EVs) that naturally originate from endosomes. They play a significant role in cellular communication. Tumor-secreted exosomes play a crucial role in cancer development and significantly contribute to tumorigenesis, angiogenesis, and metastasis by intracellular communication. Tumor-derived exosomes (TEXs) are a promising biomarker source of cancer detection in the early stages. On the other hand, they offer revolutionary cutting-edge approaches to cancer therapeutics. Exosomes offer a cell-free approach to cancer therapeutics, which overcomes immune cell and stem cell therapeutics-based limitations (complication, toxicity, and cost of treatment). There are multiple sources of therapeutic exosomes present (stem cells, immune cells, plant cells, and synthetic and modified exosomes). This article explores the dynamic source of exosomes (plants, mesenchymal stem cells, and immune cells) and their modification (chimeric, hybrid exosomes, exosome-based CRISPR, and drug delivery) based on cancer therapeutic development. This review also highlights exosomes based clinical trials and the challenges and future orientation of exosome research. We hope that this article will inspire researchers to further explore exosome-based cancer therapeutic platforms for precision oncology.

Comparison of Lung Tissue-Derived Extracellular Vesicles Using Multiple Dissociation Methods for Profiling Protein Biomarkers.

Extracellular vesicles (EVs) operate as chemical messengers that facilitate intercellular communication. Emerging evidence has demonstrated that lung tissue-derived EVs play pivotal roles in pulmonary physiological processes and have potential as biomarkers and therapeutics for lung diseases. Multiple methods have been proposed for the isolation of lung tissue-derived EVs. However, the effects of different tissue pre-treatments on lung EV isolation and subsequent disease biomarker discovery have not yet been comprehensively investigated. In this study, we compared the physical characteristics, recovery yields, and protein compositions of EVs isolated from lung tissues using three methods based on different tissue dissociation principles. Methodologically, the beneficial roles of blood perfusion and gentle meshing were emphasized based on their impact on EV yield and purity. These results demonstrate that different methods enrich distinct subpopulations of EVs that exhibit significant differences in their protein cargo and surface properties. These disparities directly affect the diagnostic detection of marker proteins related to lung diseases, including lung tumors, asthma, and pulmonary fibrosis. Collectively, these findings highlight the variations in EV characteristics resulting from the applied approaches and offer compelling suggestions for guiding researchers in selecting a suitable isolation method based on downstream functional studies and clinical applications.

Isolation and characterization of bone mesenchymal cell small extracellular vesicles using a novel mouse model.

Extracellular vesicles (EVs) are key mediators of cell-cell communication and are involved in transferring specific biomolecular cargo to recipient cells to regulate their physiological functions. A major challenge in the understanding of EV function in vivo is the difficulty ascertaining the origin of the EV particles. The recent development of the "Snorkel-tag", which includes EV-membrane-targeted CD81 fused to a series of extra-vesicular protein tags, can be used to mark EVs originating from a specific source for subsequent isolation and characterization. We developed an in vivo mouse model, termed "CAGS-Snorkel", which expresses the Snorkel-tag under the control of the Cre-lox system, and crossed this mouse with either Prx1-Cre (mesenchymal progenitors) or Ocn-Cre (osteoblasts/osteocytes) and isolated Snorkel-tagged EVs from the mouse bone marrow plasma using a magnetic bead affinity column. miRNA-sequencing was performed on the isolated EVs, and although similar profiles were observed, a few key miRNAs involved in bone metabolism (miR-106b-5p, miRs-19b-3p and miRs-219a-5p) were enriched in the Ocn-derived relative to the Prx1-derived EV subpopulations. To characterize the effects of these small EVs on a bone cell target, cultured mouse bone marrow stromal cells (mBMSCs) were treated with Prx1 or Ocn EVs, and mRNA-sequencing was performed. Pathways involved in ossification, bone development and extracellular matrix interactions were regulated by both EV subpopulations, whereas a few pathways including advanced glycation end-products (AGE) signaling, were uniquely regulated in the Ocn EV subpopulation, underlying important biological effects of specific EV subpopulations within the bone marrow microenvironment. These data demonstrate that EV isolation in vivo using the CAGS-Snorkel mouse model is a useful tool in characterizing the cargo and understanding the biology of tissue-specific EVs. Moreover, while bone mesenchymal cell populations share a common EV secretory profile, we uncover key differences based on the stage of osteoblastic differentiation that may have important biological consequences.

Orthogonal analysis reveals inconsistencies in cargo loading of extracellular vesicles.

Since extracellular vesicles (EVs) have emerged as a promising drug delivery system, diverse methods have been used to load them with active pharmaceutical ingredients (API) in preclinical and clinical studies. However, there is yet to be an engineered EV formulation approved for human use, a barrier driven in part by the intrinsic heterogeneity of EVs. API loading is rarely assessed in the context of single vesicle measurements of physicochemical properties but is likely administered in a heterogeneous fashion to the detriment of a consistent product. Here, we applied a suite of single-particle resolution methods to determine the loading of rhodamine 6G (R6G) surrogate cargo mimicking hydrophilic small molecule drugs across four common API loading methods: sonication, electroporation, freeze-thaw cycling and passive incubation. Loading efficiencies and alterations in the physical properties of EVs were assessed, as well as co-localization with common EV-associated tetraspanins (i.e., CD63, CD81 and CD9) for insight into EV subpopulations. Sonication had the highest loading efficiency, yet significantly decreased particle yield, while electroporation led to the greatest number of loaded API particles, albeit at a lower efficiency. Moreover, results were often inconsistent between repeated runs within a given method, demonstrating the difficulty in developing a rigorous loading method that consistently loaded EVs across their heterogeneous subpopulations. This work highlights the significance of how chosen quantification metrics can impact apparent conclusions and the importance of single-particle characterization of EV loading.

Simultaneous detection of membrane protein and mRNA at single extracellular vesicle level by droplet microfluidics for cancer diagnosis

IntroductionSimultaneous detection of proteins and mRNA within a single extracellular vesicle (EV) enables comprehensive analysis of specific EVs subpopulations, significantly advancing cancer diagnostics. However, developing a sensitive and user-friendly approach for simultaneously detecting multidimensional biomarkers in single EV is still challenging. ObjectivesTo facilitate the analysis of multidimensional biomarkers in EVs and boost its clinical application, we present a versatile droplet digital system facilitating the concurrent detection of membrane proteins and mRNA at the single EV level with high sensitivity and specificity. MethodsThe antibody-DNA conjugates were firstly prepared for EVs protein biomarkers recognition and signal transformation. Coupling with the assembled triplex droplet digital PCR system, a versatile droplet digital analysis assay for simultaneous detection of membrane protein and mRNA at a single EV level was developed. ResultsOur new droplet digital system displayed high sensitivity and specificity. Additionally, its clinical application was validated in a breast cancer cohort. As expected, this assay has demonstrated superior performance in distinguishing breast cancer from healthy individuals and benign controls through combined detection of EVs protein and mRNA markers compared to any single kind marker detections, especially for patients with breast cancer at early stage (AUC=0.9229). ConclusionConsequently, this study proposes a promising strategy for accurately identifying and analyzing specific EV subgroups through the co-detection of proteins and mRNA at the single EV level, holding significant potential for future clinical applications.

Exploring novel circulating biomarkers for liver cancer through extracellular vesicle characterization with infrared spectroscopy and plasmonics

BackgroundHepatocellular carcinoma (HCC) is the most common form of liver cancer, with cirrhosis being a major risk factor. Traditional blood markers like alpha-fetoprotein (AFP) demonstrate limited efficacy in distinguishing between HCC and cirrhosis, underscoring the need for more effective diagnostic methodologies. In this context, extracellular vesicles (EVs) have emerged as promising candidates; however, their practical diagnostic application is restricted by the current lack of label-free methods to accurately profile their molecular content. To address this gap, our study explores the potential of mid-infrared (mid-IR) spectroscopy, both alone and in combination with plasmonic nanostructures, to detect and characterize circulating EVs. ResultsEVs were extracted from HCC and cirrhotic patients. Mid-IR spectroscopy in the Attenuated Total Reflection (ATR) mode was utilized to identify potential signatures for patient classification, highlighting significant changes in the Amide I-II region (1475-1700 cm−1). This signature demonstrated diagnostic performance comparable to AFP and surpassed it when the two markers were combined. Further investigations utilized a plasmonic metasurface suitable for ultrasensitive spectroscopy within this spectral range. This device consists of two sets of parallel rod-shaped gold nanoantennas (NAs); the longer NAs produced an intense near-field amplification in the Amide I-II bands, while the shorter NAs were utilized to provide a sharp reflectivity edge at 1800–2200 cm−1 for EV mass-sensing. A clinically relevant subpopulation of EVs was targeted by conjugating NAs with an antibody specific to Epithelial Cell Adhesion Molecule (EpCAM). This methodology enabled the detection of variations in the quantity of EpCAM-presenting EVs and revealed changes in the Amide I-II lineshape. SignificanceThe presented results can positively impact the development of novel laboratory methods for the label-free characterization of EVs, based on the combination between mid-IR spectroscopy and plasmonics. Additionally, data obtained by using HCC and cirrhotic subjects as a model system, suggest that this approach could be adapted for monitoring these conditions.

Established a therapeutic response prediction model in metastatic gastric cancer by liquid biopsy

AbstractThis study by Okuno et al. successfully identified eight exo‐miRNAs through exosome‐based discovery and established an exo‐miRNA‐based liquid biopsy assay for predicting therapeutic response in metastatic gastric cancer (mGC). Exosomes, a subpopulation of extracellular vesicles originating from endosomes, play a crucial role in this context. Liquid biopsy, analyzing blood for circulating tumor cells, extracellular vesicles, or cell‐free nucleic acid, has revolutionized cancer diagnosis and monitoring. It significantly contributes to early detection, staging, and relapse detection in various cancers. Numerous studies have highlighted the clinical significance of miRNA and lncRNA within extracellular vesicles. The authors developed a response‐prediction model for chemo‐responsiveness in mGC patients. This study's model predicts responses robustly, demonstrating its potential efficacy in clinical practice. It offers a non‐invasive and accessible method for therapeutic response prediction, crucial for precision medicine in mGC. Successful translation of these findings into clinical applications promises substantial benefits for patient care.

Extracellular vesicles from primary human macrophages stimulated with VIP or PACAP mediate anti-SARS-CoV-2 activities in monocytes through NF-κB signaling pathway

Infection by SARS-CoV-2 is associated with uncontrolled inflammatory response during COVID-19 severe disease, in which monocytes are one of the main sources of pro-inflammatory mediators leading to acute respiratory distress syndrome. Extracellular vesicles (EVs) from different cells play important roles during SARS-CoV-2 infection, but investigations describing the involvement of EVs from primary human monocyte-derived macrophages (MDM) on the regulation of this infection are not available. Here, we describe the effects of EVs released by MDM stimulated with the neuropeptides VIP and PACAP on SARS-CoV-2-infected monocytes. MDM-derived EVs were isolated by differential centrifugation of medium collected from cells cultured for 24 h in serum-reduced conditions. Based on morphological properties, we distinguished two subpopulations of MDM-EVs, namely large (LEV) and small EVs (SEV). We found that MDM-derived EVs stimulated with the neuropeptides inhibited SARS-CoV-2 RNA synthesis/replication in monocytes, protected these cells from virus-induced cytopathic effects and reduced the production of pro-inflammatory mediators. In addition, EVs derived from VIP- and PACAP-treated MDM prevented the SARS-CoV-2-induced NF-κB activation. Overall, our findings suggest that MDM-EVs are endowed with immunoregulatory properties that might contribute to the antiviral and anti-inflammatory responses in SARS-CoV-2-infected monocytes and expand our knowledge of EV effects during COVID-19 pathogenesis.

Tumor and cancer stem cells‐derived exosomes interplay: A secret of cancer complications

AbstractCancer stem cells (CSCs) are a small subset of tumor cells, efficient in self‐renewal within the tumor and also play a vital role in cancer resistance and metastasis. Recent cancer research has focused on exosomes, a tiny subpopulation of extracellular vesicles (EVs), known for their role in intercellular communication, and significantly contributing to tumor development and metastasis (Tumor derived exosomes‐TEXs). These exosomes complicate cancer treatment by promoting tumor and CSC formation and developing drug and therapeutic resistance. This article explores how tumor‐derived exosomes impact CSC survival, proliferation, and resistance to therapies, leading to tumor recurrence. In a tumor microenvironment (TME), exosomes facilitate tumor growth and metastasis. Targeting exosomes could disrupt CSC communication and improve cancer treatment efficacy. Current studies highlight the role of CSCs exosomes in cancer progression and therapeutic resistance. Understanding CSCs exosome‐based cell‐to‐cell communication in tumor opens a new horizon in cancer therapeutics development.

Investigation of on-line electrokinetic enrichment strategies for capillary electrophoresis of extracellular vesicles

This work explores strategies for electrokinetic preconcentration of extracellular vesicles (EVs) that are potential source of biomarkers for different diseases. The first approach that led to successful preconcentration of EVs is based on large volume sample stacking (LVSS), allowing an enrichment factor of 7 for CE of EVs with long-end injection (using a capillary with an effective length of 50 cm). Attempts were also made to perform multiple cycles of LVSS, field amplified sample stacking (FASS) and field amplified sample injection (FASI), to improve EVs preconcentration performance. The focus was then put on development of capillary isotachophoresis under high ionic strengths (IS) for electrokinetic enrichment of slow migrating EVs having heterogeneous mobilities. This approach relies on the use of extremely high concentrations of the terminating electrolyte (TE) to slow down the mobility of TE co-ions, rendering them slower than those of EVs. The limit of detection for intact EVs using the developed ITP-UV method reached 8.3 × 108 EVs/mL, allowing an enrichment of 25 folds and a linear calibration up to 4 × 1010 EVs/mL. The ITP-UV and ITP-LIF approaches were applied to provide the electrokinetic signature of EVs of bovine milk and human plasma as well as to visualize more specifically intravesicular fluorescently labelled EVs. The investigation of these strategies shredded light into the challenges still encountered with electrokinetic preconcentration and separation of heterogeneous EVs sub-populations which are discussed herein based on our results and other attempts reported in the literature.

Tetranuclear Polypyridylruthenium(II) Complexes as Selective Nucleic Acid Stains for Flow Cytometric Analysis of Monocytic and Epithelial Lung Carcinoma Large Extracellular Vesicles.

Selective staining of extracellular vesicles (EVs) is a major challenge for diagnostic and therapeutic applications. Herein, the EV labeling properties of a new class of tetranuclear polypyridylruthenium(II) complexes, Rubb7-TNL and Rubb7-TL, as phosphorescent stains are described. These new stains have many advantages over standard stains to detect and characterize EVs, including: high specificity for EV staining versus cell staining; high phosphorescence yields; photostability; and a lack of leaching from EVs until incorporation with target cells. As an example of their utility, large EVs released from control (basal) or lipopolysaccharide (LPS)-stimulated THP-1 monocytic leukemia cells were studied as a model of immune system EVs released during bacterial infection. Key findings from EV staining combined with flow cytometry were as follows: (i) LPS-stimulated THP-1 cells generated significantly larger and more numerous large EVs, as compared with those from unstimulated cells; (ii) EVs retained native EV physical properties after staining; and (iii) the new stains selectively differentiated intact large EVs from artificial liposomes, which are models of cell membrane fragments or other lipid-containing debris, as well as distinguished two distinct subpopulations of monocytic EVs within the same experiment, as a result of biochemical differences between unstimulated and LPS-stimulated monocytes. Comparatively, the staining patterns of A549 epithelial lung carcinoma-derived EVs closely resembled those of THP-1 cell line-derived EVs, which highlighted similarities in their selective staining despite their distinct cellular origins. This is consistent with the hypothesis that these new phosphorescent stains target RNA within the EVs.