The interplay of extracellular vesicles in the pathogenesis of metabolic impairment and type 2 diabetes.

The pathogenesis of type 2 diabetes (T2D) involves dysfunction in multiple organs, including the liver, muscle, adipose tissue, and pancreas, leading to insulin resistance and ß cell failure. Recent studies highlight the significant role of extracellular vesicles (EVs) in mediating inter-organ communication in T2D. This review investigates the role of EVs, focusing on their presence and biological significance in human plasma and tissues affected by T2D. We explore specific EV cargo, such as miRNAs and proteins, which affect insulin signaling and glucose metabolism, emphasizing their potential as biomarkers. By highlighting the diagnostic and therapeutic potential of EVs, we aim to provide new insights into their role in early detection, disease monitoring, and innovative treatment strategies for T2D.

Therapeutic Application of Extracellular Vesicles Derived from Mesenchymal Stem Cells in Domestic Animals.

Recently, the therapeutic potential of extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) has been extensively studied in both human and veterinary medicine. EVs are nano-sized particles containing biological components commonly found in other biological materials. For that reason, EV isolation and characterization are critical to draw precise conclusions during their investigation. Research on EVs within veterinary medicine is still considered in its early phases, yet numerous papers were published in recent years. The conventional adult tissues for deriving MSCs include adipose tissue and bone marrow. Nonetheless, alternative sources such as synovial fluid, endometrium, gingiva, and milk have also been intermittently used. Fetal adnexa are amniotic membrane/fluid, umbilical cord and Wharton's jelly. Cells derived from fetal adnexa exhibit an intermediate state between embryonic and adult cells, demonstrating higher proliferative and differentiative potential and longer telomeres compared to cells from adult tissues. Summarized here are the principal and recent preclinical and clinical studies performed in domestic animals such as horse, cattle, dog and cat. To minimize the use of antibiotics and address the serious issue of antibiotic resistance as a public health concern, they will undoubtedly also be utilized in the future to treat infections in domestic animals. A number of concerns, including large-scale production with standardization of EV separation and characterization techniques, must be resolved for clinical application.

Selective Enrichment of Angiomirs in Extracellular Vesicles Released from Ischemic Skeletal Muscles: Potential Role in Angiogenesis and Neovascularization.

MicroRNAs (miRs) regulate physiological and pathological processes, including ischemia-induced angiogenesis and neovascularization. They can be transferred between cells by extracellular vesicles (EVs). However, the specific miRs that are packaged in EVs released from skeletal muscles, and how this process is modulated by ischemia, remain to be determined. We used a mouse model of hindlimb ischemia and next generation sequencing (NGS) to perform a complete profiling of miR expression and determine the effect of ischemia in skeletal muscles, and in EVs of different sizes (microvesicles (MVs) and exosomes) released from these muscles. Ischemia significantly modulated miR expression in whole muscles and EVs, increasing the levels of several miRs that can have pro-angiogenic effects (angiomiRs). We found that specific angiomiRs are selectively enriched in MVs and/or exosomes in response to ischemia. In silico approaches indicate that these miRs modulate pathways that play key roles in angiogenesis and neovascularization, including HIF1/VEGF signaling, regulation of actin cytoskeleton and focal adhesion, NOTCH, PI3K/AKT, RAS/MAPK, JAK/STAT, TGFb/SMAD signaling and the NO/cGMP/PKG pathway. Thus, we show for the first time that angiomiRs are selectively enriched in MVs and exosomes released from ischemic muscles. These angiomiRs could be targeted in order to improve the angiogenic function of EVs for potential novel therapeutic applications in patients with severe ischemic vascular diseases.

Human mesenchymal stem cells-derived microvesicles increase oligodendrogenesis and neurogenesis of cultured adult neural stem cells.

Mesenchymal stem cells (MSCs) are involved in tissue repair and anti-inflammatory activities and have shown promising therapeutic efficiency in different animal models of neurodegenerative disorders. Microvesicles (MVs), implicated in cellular communication, are secreted from MSCs and play a key role in determining the fate of cell differentiation. Our study examines the effect of human umbilical cord MSC-derived MVs (hUC-MSC MVs) on the proliferation and differentiation potential of adult neural stem cells (NSCs). Results showed that 0.2 µg MSC derived MVs significantly increased the viability of NSCs and their proliferation, as demonstrated by an increase in the number of neurospheres and their derived cells, compared to controls. In addition, all hUC-MSC MVs concentrations (0.1, 0.2 and 0.4 µg) induced the differentiation of NSCs toward precursors (Olig2 + ) and mature oligodendrocytes (MBP+). This increase in mature oligodendrocytes was inversely proportional to the dose of MVs. Moreover, hUC-MSC MVs induced the differentiation of NSCs into neurons (ß-tubulin + ), in a dose-dependent manner, but had no effect on astrocytes (GFAP+). Furthermore, treatment of NSCs with hUC-MSC MVs (0.1 and 0.2 µg) significantly increased the expression levels of the proliferation marker Ki67 gene, compared to controls. Finally, hUC-MSC MVs (0.1 µg) significantly increased the expression level of Sox10 transcripts; but not Pax6 gene, demonstrating an increased NSC ability to differentiate into oligodendrocytes. In conclusion, our study showed that hUC-MSC MVs increased NSC proliferation in vitro and induced NSC differentiation into oligodendrocytes and neurons, but not astrocytes.

Evaluation of circulating microvesicles and their procoagulant activity in patients with COVID-19.

OBJECTIVE: Several pathological conditions trigger the formation of microvesicles (MVs), including infectious diseases such as COVID-19. The shedding of MVs increases the levels of inflammatory factors (e.g., interleukin-6; IL-6) and ultimately leads to an inflammatory cascade response, while also increasing the procoagulant response. The current study aimed to evaluate the level of circulating MVs and their procoagulant activity as well as the serum level of IL-6 in patients with COVID-19 and healthy controls. In this case-control study, 65 patients with COVID-19 and 30 healthy individuals were sampled after obtaining written informed consent. MVs counting was measured using conjugated CD61, CD45, CD235a, and Annexin-V antibodies. Additionally, the procoagulant activity of MVs and the IL-6 level were estimated using enzyme-linked immunosorbent assay (ELISA). RESULTS: The majority of MVs were platelet-derived MVs (PMVs). Patients with COVID-19 had significantly higher levels of MVs, procoagulant MVs, and IL-6 compared to healthy controls (p < 0.001). MVs were significantly correlated with procoagulant MVs, D-Dimer levels, fibrinogen, and IL-6, but not with platelet, lymphocyte, and neutrophil counts. CONCLUSION: Elevated levels of procoagulant MVs and their association with inflammatory and coagulation markers in patients with COVID-19 are suggested as a novel circulatory biomarker to evaluate and predict the procoagulant activity and severity of COVID-19.

Mitochondria-containing extracellular vesicles from mouse vs. human brain endothelial cells for ischemic stroke therapy.

Ischemic stroke-induced mitochondrial dysfunction in the blood-brain barrier-forming brain endothelial cells (BECs) results in long-term neurological dysfunction post-stroke. We previously reported data from a pilot study where intravenous administration of human BEC (hBEC)-derived mitochondria-containing extracellular vesicles (EVs) showed a potential efficacy signal in a mouse middle cerebral artery occlusion (MCAo) model of stroke. We hypothesized that EVs harvested from donor species homologous to the recipient species (e.g., mouse) may improve therapeutic efficacy, and therefore, use of mouse BEC (mBEC)-derived EVs may improve post-stroke outcomes in MCAo mice. We investigated potential differences in the mitochondria transfer of EVs derived from the same species as the recipient cell (mBEC-EVs and recipient mBECs or hBECs-EVs and recipient hBECs) vs. cross-species EVs and recipient cells (mBEC-EVs and recipient hBECs or vice versa). Our results showed that while both hBEC- and mBEC-EVs transferred EV mitochondria, mBEC-EVs outperformed hBEC-EVs in increasing ATP levels and improved recipient mBEC mitochondrial function via increasing oxygen consumption rates. mBEC-EVs significantly reduced brain infarct volume and neurological deficit scores compared to vehicle-injected MCAo mice. The superior therapeutic efficacy of mBEC-EVs in MCAo mice support the continued use of mBEC-EVs to optimize the therapeutic potential of mitochondria-containing EVs in preclinical mouse models.

CD66b+/CD68+ circulating extracellular vesicles, lactate dehydrogenase and neutrophil-to-lymphocyte ratio can differentiate coronavirus disease 2019 severity during and after infection.

Coronavirus disease 2019 (COVID-19) has been a major public health burden. We hypothesised that circulating extracellular vesicles (cEVs), key players in health and disease, could trace the cell changes during COVID-19 infection and recovery. Therefore, we studied the temporal trend of cEV and inflammatory marker levels in plasma samples of COVID-19 patients that were collected within 24 h of patient admission (baseline, n = 80) and after hospital discharge at day-90 post-admission (n = 59). Inflammatory markers were measured by standard biochemical methods. cEVs were quantitatively and phenotypically characterized by high-sensitivity nano flow cytometry. In patients recovered from COVID-19 lower levels of inflammatory markers were detected. cEVs from vascular (endothelial cells) and blood (platelets, distinct immune subsets) cells were significantly reduced at day-90 compared to admission levels, a pattern also observed for cEVs from progenitor, perivascular and epithelial cells. The best discriminatory power for COVID-19 severity was found for inflammatory markers lactate dehydrogenase and neutrophil-to-lymphocyte ratio and for granulocyte/macrophage-released CD66b+/CD68+-cEVs. Albeit inflammatory markers were good indicators of systemic inflammatory response and discriminators of COVID-19 remission, they do not completely reveal cell stress and organ damage states. cEVs reaching baseline pre-infection levels at 90 days post-infection in recovered patients discriminate parental cells affected by disease.

Mitochondrial DNA-boosted dendritic cell-based nanovaccination triggers antitumor immunity in lung and pancreatic cancers.

Low migratory dendritic cell (DC) levels pose a challenge in cancer immune surveillance, yet their impact on tumor immune status and immunotherapy responses remains unclear. We present clinical evidence linking reduced migratory DC levels to immune-cold tumor status, resulting in poor patient outcomes. To address this, we develop an autologous DC-based nanovaccination strategy using patient-derived organoid or cancer cell lysate-pulsed cationic nanoparticles (cNPs) to load immunogenic DC-derived microvesicles (cNPcancer cell@MVDC). This approach transforms immune-cold tumors, increases migratory DCs, activates T cells and natural killer cells, reduces tumor growth, and enhances survival in orthotopic pancreatic and lung cancer models, surpassing conventional methods. In vivo imaging reveals superior cNPcancer cell@MVDC accumulation in tumors and lymph nodes, promoting immune cell infiltration. Mechanistically, cNPs enrich mitochondrial DNA, enhancing cGAS-STING-mediated DC activation and migration. Our strategy shifts cold tumors to a hot state, enhancing antitumor immunity for potential personalized cancer treatments.

Ceramide-mediated orchestration of oxidative stress response through filopodia-derived small extracellular vesicles.

Extracellular vesicles (EVs) are shed from the plasma membrane, but the regulation and function of these EVs remain unclear. We found that oxidative stress induced by H2O2 in Hela cells stimulated filopodia formation and the secretion of EVs. EVs were small (150 nm) and labeled for CD44, indicating that they were derived from filopodia. Filopodia-derived small EVs (sEVs) were enriched with the sphingolipid ceramide, consistent with increased ceramide in the plasma membrane of filopodia. Ceramide was colocalized with neutral sphingomyelinase 2 (nSMase2) and acid sphingomyelinase (ASM), two sphingomyelinases generating ceramide at the plasma membrane. Inhibition of nSMase2 and ASM prevented oxidative stress-induced sEV shedding but only nSMase2 inhibition prevented filopodia formation. nSMase2 was S-palmitoylated and interacted with ASM in filopodia to generate ceramide for sEV shedding. sEVs contained nSMase2 and ASM and decreased the level of these two enzymes in oxidatively stressed Hela cells. A novel metabolic labeling technique for EVs showed that oxidative stress induced secretion of fluorescent sEVs labeled with NBD-ceramide. NBD-ceramide-labeled sEVs transported ceramide to mitochondria, ultimately inducing cell death in a proportion of neuronal (N2a) cells. In conclusion, using Hela cells we provide evidence that oxidative stress induces interaction of nSMase2 and ASM at filopodia, which leads to shedding of ceramide-rich sEVs that target mitochondria and propagate cell death.

Deciphering m6A methylation in monocyte-mediated cardiac fibrosis and monocyte-hitchhiked erythrocyte microvesicle biohybrid therapy.

Rationale: Device implantation frequently triggers cardiac remodeling and fibrosis, with monocyte-driven inflammatory responses precipitating arrhythmias. This study investigates the role of m6A modification enzymes METTL3 and METTL14 in these responses and explores a novel therapeutic strategy targeting these modifications to mitigate cardiac remodeling and fibrosis. Methods: Peripheral blood mononuclear cells (PBMCs) were collected from patients with ventricular septal defects (VSD) who developed conduction blocks post-occluder implantation. The expression of METTL3 and METTL14 in PBMCs was measured. METTL3 and METTL14 deficiencies were induced to evaluate their effect on angiotensin II (Ang II)-induced myocardial inflammation and fibrosis. m6A modifications were analyzed using methylated RNA immunoprecipitation followed by quantitative PCR. NF-κB pathway activity and levels of monocyte migration and fibrogenesis markers (CXCR2 and TGF-ß1) were assessed. An erythrocyte microvesicle-based nanomedicine delivery system was developed to target activated monocytes, utilizing the METTL3 inhibitor STM2457. Cardiac function was evaluated via echocardiography. Results: Significant upregulation of METTL3 and METTL14 was observed in PBMCs from patients with VSD occluder implantation-associated persistent conduction block. Deficiencies in METTL3 and METTL14 significantly reduced Ang II-induced myocardial inflammation and fibrosis by decreasing m6A modification on MyD88 and TGF-ß1 mRNAs. This disruption reduced NF-κB pathway activation, lowered CXCR2 and TGF-ß1 levels, attenuated monocyte migration and fibrogenesis, and alleviated cardiac remodeling. The erythrocyte microvesicle-based nanomedicine delivery system effectively targeted inflamed cardiac tissue, reducing inflammation and fibrosis and improving cardiac function. Conclusion: Inhibiting METTL3 and METTL14 in monocytes disrupts the NF-κB feedback loop, decreases monocyte migration and fibrogenesis, and improves cardiac function. Targeting m6A modifications of monocytes with STM2457, delivered via erythrocyte microvesicles, reduces inflammation and fibrosis, offering a promising therapeutic strategy for cardiac remodeling associated with device implantation.

Plasma NOTCH3 and the risk of cardiovascular recurrence in patients with ischemic stroke.

BACKGROUND: Ischemic stroke patients are more prone to developing another cardiovascular event. AIM: This study aims to examine potential biological predispositions to cardiovascular recurrence in patients with ischemic stroke. DESIGN: Human and preclinical studies. METHODS: Quantitative proteomic analysis, animal stroke, atherosclerosis models and circulating endothelial cells (CECs) were employed to examine candidate biomarkers derived from an ischemic stroke cohort in Singapore. RESULTS: Proteomic analysis of pooled microvesicles of "Event" (n = 24) and without "Event" (n = 24) samples identified NOTCH3 as a candidate marker; plasma NOTCH3 were shown to be elevated in "Event" patients compared to those without "Events" and age-matched controls. In a validation cohort comprising 431 prospectively recruited ischemic stroke patients (mean age 59.1 years; median follow-up 3.5 years), men with plasma NOTCH3 (>1600pg/ml) harbored increased risk of cardiovascular recurrence (adjusted hazards ratio 2.29, 95% CI 1.10-4.77); no significant association was observed in women. Chronic renal failure, peripheral artery disease and NT-pro-brain natriuretic peptide were significant predictors of plasma NOTCH3 in men without ischemic stroke (adjusted r2=0.43). Following middle cerebral artery occlusion, NOTCH3 expression in mouse sera increased and peaked at 24 hrs, persisting thereafter for at least 72 hours. In Apoe-/- atherosclerotic mice, NOTCH3 stained the endothelium of defective arterial lining and atherosclerotic plaques. Analysis of CECs isolated from stroke patients revealed increased gene expression of NOTCH3, further supporting endothelial damage underpinning NOTCH3-mediated atherosclerosis. CONCLUSION: Findings from this study suggests that NOTCH3 could be important in cardiovascular recurrence following an ischemic stroke.

Endothelial-derived microvesicles promote pro-migratory cross-talk with smooth muscle cells by a mechanism requiring tissue factor and PAR2 activation.

Introduction: Microvesicles (MV) released by endothelial cells (EC) following injury or inflammation contain tissue factor (TF) and mediate communication with the underlying smooth muscle cells (SMC). Ser253-phosphorylated TF co-localizes with filamin A at the leading edge of migrating SMC. In this study, the influence of endothelial-derived TF-MV, on human coronary artery SMC (HCASMC) migration was examined. Methods and Results: MV derived from human coronary artery EC (HCAEC) expressing TFWt accelerated HCASMC migration, but was lower with cytoplasmic domain-deleted TF. Furthermore, incubation with TFAsp253-MV, or expression of TFAsp253 in HCASMC, reduced cell migration. Blocking TF-factor VIIa (TF-fVIIa) procoagulant/protease activity, or inhibiting PAR2 signaling on HCASMC, abolished the accelerated migration. Incubation with fVIIa alone increased HCASMC migration, but was significantly enhanced on supplementation with TF. Neither recombinant TF alone, factor Xa, nor PAR2-activating peptide (SLIGKV) influenced cell migration. In other experiments, HCASMC were transfected with peptides corresponding to the cytoplasmic domain of TF prior to stimulation with TF-fVIIa. Cell migration was suppressed only when the peptides were phosphorylated at position of Ser253. Expression of mutant forms of filamin A in HCASMC indicated that the enhancement of migration by TF but not by PDGF-BB, was dependent on the presence of repeat-24 within filamin A. Incubation of HCASMC with TFWt-MV significantly reduced the levels of Smoothelin-B protein, and upregulated FAK expression. Discussion: In conclusion, Ser253-phosphorylated TF and fVIIa released as MV-cargo by EC, act in conjunction with PAR2 on SMC to promote migration and may be crucial for normal arterial homeostasis as well as, during development of vascular disease.

Extracellular vesicles at the crossroad between cancer progression and immunotherapy: focus on dendritic cells.

Extracellular vesicles (EVs) are nanosized heat-stable vesicles released by virtually all cells in the body, including tumor cells and tumor-infiltrating dendritic cells (DCs). By carrying molecules from originating cells, EVs work as cell-to-cell communicators in both homeostasis and cancer but may also represent valuable therapeutic and diagnostic tools. This review focuses on the role of tumor-derived EVs (TEVs) in the modulation of DC functions and on the therapeutic potential of both tumor- and DC-derived EVs in the context of immunotherapy and DC-based vaccine design. TEVs were originally characterized for their capability to transfer tumor antigens to DCs but are currently regarded as mainly immunosuppressive because of the expression of DC-inhibiting molecules such as PD-L1, HLA-G, PGE2 and others. However, TEVs may still represent a privileged system to deliver antigenic material to DCs upon appropriate engineering to reduce their immunosuppressive cargo or increase immunogenicity. DC-derived EVs are more promising than tumor-derived EVs since they expose antigen-loaded MHC, costimulatory molecules and NK cell-activating ligands in the absence of an immunosuppressive cargo. Moreover, DC-derived EVs possess several advantages as compared to cell-based drugs such as a higher antigen/MHC concentration and ease of manipulation and a lower sensitivity to immunosuppressive microenvironments. Preclinical models showed that DC-derived EVs efficiently activate tumor-specific NK and T cell responses either directly or indirectly by transferring antigens to tumor-infiltrating DCs. By contrast, however, phase I and II trials showed a limited clinical efficacy of EV-based anticancer vaccines. We discuss that the future of EV-based therapy depends on our capability to overcome major challenges such as a still incomplete understanding of their biology and pharmacokinetic and the lack of standardized methods for high-throughput isolation and purification. Despite this, EVs remain in the limelight as candidates for cancer immunotherapy which may outmatch cell-based strategies in the fullness of their time.

Efficacy of stem cells versus microvesicles in ameliorating chronic renal injury in rats (histological and biochemical study).

Chronic exposure to heavy metals as aluminum chloride (AlCl3) could result in severe health hazards such as chronic renal injury. The present study aimed to evaluate the therapeutic potential of adipose tissue-derived stem cells (ASCs) in comparison to their microvesicles (MV) in AlCl3-induced chronic renal injury. Forty-eight adult male Wistar rats were divided into four groups: Control group, AlCl3-treated group, AlCl3/ASC-treated group, and AlCl3/MV-treated group. Biochemical studies included estimation of serum urea and creatinine levels, oxidative biomarkers assay, antioxidant biomarkers, serum cytokines (IL-1ß, IL-8, IL-10, and IL-33), real time-PCR analysis of renal tissue MALT1, TNF-α, IL-6, and serum miR-150-5p expression levels. Histopathological studies included light and electron microscopes examination of renal tissue, Mallory trichrome stain for fibrosis, Periodic acid Schiff (PAS) stain for histochemical detection of carbohydrates, and immunohistochemical detection of Caspase-3 as apoptosis marker, IL-1B as a proinflammatory cytokine and CD40 as a marker of MVs. AlCl3 significantly deteriorated kidney function, enhanced renal MDA and TOS, and serum cytokines concentrations while decreased the antioxidant parameters (SOD, GSH, and TAC). Moreover, serum IL-10, TNF-α, miR-150-5p, and renal MALT1 expression values were significantly higher than other groups. Kidney sections showed marked histopathological damage in both renal cortex and medulla in addition to enhanced apoptosis and increased inflammatory cytokines immunoexpression than other groups. Both ASCs and MVs administration ameliorated the previous parameters levels with more improvement was detected in MVs-treated group. In conclusion: ASCs-derived MVs have a promising ameliorating effect on chronic kidney disease.

Food-derived vesicles as immunomodulatory drivers: Current knowledge, gaps, and perspectives.

Extracellular vesicles (EVs) are lipid-bound membrane vesicles released from cells, containing active compounds, which can be found in different foods. In this review, the role of food-derived vesicles (FDVs) as immunomodulatory drivers is summarized, with a focus on sources, isolation techniques and yields, as well as bioavailability and potential health implications. In addition, gaps and perspectives detected in this research field have been highlighted. FDVs have been efficiently extracted from different sources, and differential ultracentrifugation seems to be the most adequate isolation technique, with yields ranging from 108 to 1014 EV particles/mL. Animal studies show promising results in how these FDVs might regulate different pathways related to inflammation. Further investigation on the production of stable components in a cost-effective way, as well as human studies demonstrating safety and health-promoting properties, since scarce information has been reported until now, in the context of modulating the immune system are needed.

Effect of human bone marrow mesenchymal stem cell-derived microvesicles on the apoptosis of the multiple myeloma cell line U266.

BACKGROUND: Microvesicles are membraned particles produced by different types of cells recently investigated for anticancer purposes. The current study aimed to investigate the effects of human bone marrow mesenchymal stem cell-derived microvesicles (BMSC-MVs) on the multiple myeloma cell line U266. BMSC-MVs were isolated from BMSCs via ultracentrifugation and characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS). U266 cells were treated with 15, 30, 60, and 120 µg/mL BMSC-MVs for three and seven days and the effects of treatment in terms of viability, cytotoxicity, and DNA damage were investigated via the MTT assay, lactate dehydrogenase (LDH) assay, and 8­hydroxy-2'-deoxyguanosine (8­OHdG) measurement, respectively. Moreover, the apoptosis rate of the U266 cells treated with 60 µg/mL BMSC-MVs was also assessed seven days following treatment via flow cytometry. Ultimately, the expression level of BCL2, BAX, and CCND1 by the U266 cells was examined seven days following treatment with 60 µg/mL BMSC-MVs using qRT-PCR. RESULTS: BMSC-MVs had an average size of ~ 410 nm. According to the MTT and LDH assays, BMSC-MV treatment reduced the U266 cell viability and mediated cytotoxic effects against them, respectively. Moreover, elevated 8­OHdG levels following BMSC-MV treatment demonstrated a dose-dependent increase of DNA damage in the treated cells. BMSC-MV-treated U266 cells also exhibited an increased apoptosis rate after seven days of treatment. The expression level of BCL2 and CCND1 decreased in the treated cells whereas the BAX expression demonstrated an incremental pattern. CONCLUSIONS: Our findings accentuate the therapeutic benefit of BMSC-MVs against the multiple myeloma cell line U266 and demonstrate how microvesicles could be of therapeutic advantage. Future in vivo studies could further corroborate these findings.

ELISA-based detection of immunoglobulins against extracellular vesicles in blood plasma.

Extracellular vesicles (EVs) are intensively investigated for their therapeutic potential and application as drug delivery vehicle. A broad perception of favourable safety profiles and low immunogenicity make EVs an attractive alternative to synthetic nanoparticles. We recently showed that repeated intravenous administration of human cell-derived EVs into pig-tailed macaques unexpectedly elicited antibody responses after three or more injections. This coincided with decreasing EV circulation time, and may thus hamper successful EV-mediated cargo delivery into tissues. Here, we share the custom ELISA protocol that we used to measure such antibody responses. This protocol may help other researchers evaluate immune responses to EV-based therapies in preclinical studies.

Surface Glycans of Microvesicles Derived from Endothelial Cells, as Probed Using Plant Lectins.

Glycans of MVs are proposed to be candidates for mediating targeting specificity or at least promoting it. In contrast to exosomes, glycomic studies of MVs are largely absent. We studied the glycoprofile of endothelial cell-derived MVs using 21 plant lectins, and the results show the dominance of oligolactosamines and their α2-6-sialylated forms as N-glycans and low levels of α2-3-sialylated glycans. The low levels of α2-3-sialosides could not be explained by the action of extracellular glycosidases. Additionally, the level of some Man-containing glycans was also decreased in MVs. Spatial masking as the causative relationship between these low level glycans (as glycosphingolipids) by integral proteins or proteoglycans (thus, their lack of interaction with lectins) seems unlikely. The results suggest that integral proteins do not pass randomly into MVs, but instead only some types, differing in terms of their specific glycosylation, are integrated into MVs.

Assessment of brain-derived extracellular vesicle enrichment for blood biomarker analysis in age-related neurodegenerative diseases: An international overview.

INTRODUCTION: Brain-derived extracellular vesicles (BEVs) in blood allows for minimally-invasive investigations of central nervous system (CNS) -specific markers of age-related neurodegenerative diseases (NDDs). Polymer-based EV- and immunoprecipitation (IP)-based BEV-enrichment protocols from blood have gained popularity. We systematically investigated protocol consistency across studies, and determined CNS-specificity of proteins associated with these protocols. METHODS: NDD articles investigating BEVs in blood using polymer-based and/or IP-based BEV enrichment protocols were systematically identified, and protocols compared. Proteins used for BEV-enrichment and/or post-enrichment were assessed for CNS- and brain-cell-type-specificity, extracellular domains (ECD+), and presence in EV-databases. RESULTS: A total of 82.1% of studies used polymer-based (ExoQuick) EV-enrichment, and 92.3% used L1CAM for IP-based BEV-enrichment. Centrifugation times differed across studies. A total of 26.8% of 82 proteins systematically identified were CNS-specific: 50% ECD+, 77.3% were listed in EV-databases. CONCLUSIONS: We identified protocol steps requiring standardization, and recommend additional CNS-specific proteins that can be used for BEV-enrichment or as BEV-biomarkers. HIGHLIGHTS: Across NDDs, we identified protocols commonly used for EV/BEV enrichment from blood. We identified protocol steps showing variability that require harmonization. We assessed CNS-specificity of proteins used for BEV-enrichment or found in BEV cargo. CNS-specific EV proteins with ECD+ or without were identified. We recommend evaluation of blood-BEV enrichment using these additional ECD+ proteins.

Evidence of Lysosomal ß-Hexosaminidase Enzymatic Activity Associated with Extracellular Vesicles: Potential Applications for the Correction of Sandhoff Disease.

Extracellular vesicles (EVs) can be isolated from biological fluids and cell culture medium. Their nanometric dimension, relative stability, and biocompatibility have raised considerable interest for their therapeutic use as delivery vehicles of macromolecules, namely nucleic acids and proteins. Deficiency in lysosomal enzymes and associated proteins is at the basis of a group of genetic diseases known as lysosomal storage disorders (LSDs), characterized by the accumulation of undigested substrates into lysosomes. Among them, GM2 gangliosidoses are due to a deficiency in the activity of lysosomal enzyme ß-hexosaminidase, leading to the accumulation of the GM2 ganglioside and severe neurological symptoms. Current therapeutic approaches, including enzyme replacement therapy (ERT), have proven unable to significantly treat these conditions. Here, we provide evidence that the lysosomal ß-hexosaminidase enzyme is associated with EVs released by HEK cells and that the EV-associated activity can be increased by overexpressing the α-subunit of ß-hexosaminidase. The delivery of EVs to ß-hexosaminidase-deficient fibroblasts results in a partial cross-correction of the enzymatic defect. Overall findings indicate that EVs could be a source of ß-hexosaminidase that is potentially exploitable for developing therapeutic approaches for currently untreatable LSDs.