Serum-derived extracellular vesicles: Novel biomarkers reflecting the disease severity of COVID-19 patients

Unveiling urinary extracellular vesicle mRNA signature for early diagnosis and prognosis of bladder cancer

Background: Bladder cancer (BC) ranks as one of the most prevalent cancers. Its early diagnosis is clinically essential but remains challenging due to the lack of reliable biomarkers. Extracellular vesicles (EVs) carry abundant biological cargoes from parental cells, rendering them as promising cancer biomarkers. Herein, we revealed that urinary EVs (uEVs) mRNA signature could serve as non-invasive biomarker for the early diagnosis and prognostic assessment for BC. Methods: Transcriptomic sequencing was conducted to reveal the mRNA signature of EVs collected from normal cell line and different grades of BC cell lines. Candidate EV-mRNA biomarkers were further profiled using clinical urine samples (n = 97, including healthy controls, BC patients and post-surgery BC patients) by RT-qPCR. Results: Three mRNAs (SRGN, FLI1, and MACROH2A2) within uEV were identified as potential biomarkers for BC, providing an area under the receiver operating characteristic curve (AUC) of 0.973 for BC diagnosis. Moreover, the uEV-mRNA panel could discriminate early-stage BC patients from healthy controls with an AUC of 0.969. Finally, we found that the uEV-mRNAs were significantly down-regulated in the post-surgery urine samples of BC patients. Conclusions: Given the facile and non-intrusive nature of urine collection, the identified uEV-mRNAs could serve as potential liquid-biopsy biomarkers for the early diagnosis and prognosis of BC.

Proteomics of circulating extracellular vesicles reveals diverse clinical presentations of COVID-19 but fails to identify viral peptides

Extracellular vesicles (EVs) released by virus-infected cells have the potential to encapsulate viral peptides, a characteristic that could facilitate vaccine development. Furthermore, plasma-derived EVs may elucidate pathological changes occurring in distal tissues during viral infections. We hypothesized that molecular characterization of EVs isolated from COVID-19 patients would reveal peptides suitable for vaccine development. Blood samples were collected from three cohorts: severe COVID-19 patients (G1), mild/asymptomatic cases (G2), and SARS-CoV-2-negative healthcare workers (G3). Samples were obtained at two time points: during the initial phase of the pandemic in early 2020 (m0) and eight months later (m8). Clinical data analysis revealed elevated inflammatory markers in G1. Notably, non-vaccinated individuals in G1 exhibited increased levels of neutralizing antibodies at m8, suggesting prolonged exposure to viral antigens. Proteomic profiling of EVs was performed using three distinct methods: immunocapture (targeting CD9), ganglioside-capture (utilizing Siglec-1) and size-exclusion chromatography (SEC). Contrary to our hypothesis, this analysis failed to identify viral peptides. These findings were subsequently validated through Western blot analysis targeting the RBD of the SARS-CoV-2 Spike protein's and comparative studies using samples from experimentally infected Syrian hamsters. Furthermore, analysis of the EV cargo revealed a diverse molecular profile, including components involved in the regulation of viral replication, systemic inflammation, antigen presentation, and stress responses. These findings underscore the potential significance of EVs in the pathogenesis and progression of COVID-19.

Extracellular vesicles containing SARS-CoV-2 proteins are associated with multi-organ dysfunction and worse outcomes in patients with severe COVID-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19) and has been related to more than 7 million deaths globally since 2019. The association of high levels of IL-6 with severe cases led to the early evaluation of the anti-IL6 inhibitor tocilizumab as a potential treatment, which unfortunately failed to improve survival in many trials. Moreover, little is known about the development of COVID-19 sequelae, and biomarkers are needed to understand and anticipate these processes. Because extracellular vesicles (EVs) play an important role in viral infection and immune response, they could potentially serve as predictive and prognostic biomarkers. We isolated EVs from 39 patients with severe COVID-19, from which 29 received tocilizumab and 10 were considered controls. Blood samples, which were collected at hospitalisation before treatment, at Day 7, and Day 15 during follow-up, were assessed by immunoblot for longitudinal expression of spike (S) and nucleocapsid (N) proteins. Dynamic expression was calculated and compared with clinicopathological and experimental variables. Expression of EV S was validated by immunogold and imaging flow-cytometry, revealing an enrichment in CD9+ EVs. As a result, decreasing expression of EV viral proteins was observed in patients treated with tocilizumab. Moreover, higher increase in EV S was observed in patients with lower antibody response, hyperfibrinogenemia, lower respiratory function, higher blood pressure and shorter outcomes. These findings lay the foundation for future studies characterizing the role of EVs in multiorgan assessment and identifying biomarkers in patients with severe COVID-19 and possible long COVID.

Plasma Extracellular Vesicles Derived from Pediatric COVID-19 Patients Modulate Monocyte and T Cell Immune Responses Based on Disease Severity

BACKGROUND

The COVID-19 pandemic has caused significant morbidity and mortality globally. The role of plasma-derived extracellular vesicles (EVs) in pediatric COVID-19 patients remains unclear.

METHODS

We isolated EVs from healthy controls (n = 13) and pediatric COVID-19 patients (n = 104) with varying severity during acute and convalescent phases using serial ultracentrifugation. EV effects on healthy PBMCs, naïve CD4+ T cells, and monocytes were assessed through in vitro assays, flow cytometry, and ELISA.

RESULTS

Our findings indicate that COVID-19 severity correlates with diverse immune responses. Severe acute cases exhibited increased cytokine levels, decreased IFNγ levels, and lower CD4+ T cell and monocyte counts, suggesting immunosuppression. EVs from severe acute patients stimulated healthy cells to express higher PDL1, increased Th2 and Treg cells, reduced IFNγ secretion, and altered Th1/Th17 ratios. Patient-derived EVs significantly reduced proinflammatory cytokine production by monocytes (p < .001 for mild, p = .0025 for severe cases) and decreased CD4+ T cell (p = .043) and monocyte (p = .033) populations in stimulated healthy PBMCs.

CONCLUSION

This study reveals the complex relationship between immunological responses and EV-mediated effects, emphasizing the impact of COVID-19 severity. We highlight the potential role of plasma-derived EVs in early-stage immunosuppression in severe COVID-19 patients.

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.

Mechanical property estimation of sarcoma-relevant extracellular vesicles using transmission electron microscopy

Analysis of single extracellular vesicles (EVs) has the potential to yield valuable label-free information on their morphological structure, biomarkers and therapeutic targets, though such analysis is hindered by the lack of reliable and quantitative measurements of the mechanical properties of these compliant nanoscale particles. The technical challenge in mechanical property measurements arises from the existing tools and methods that offer limited throughput, and the reported elastic moduli range over several orders of magnitude. Here, we report on a flow-based method complemented by transmission electron microscopy (TEM) imaging to provide a high throughput, whole EV deformation analysis for estimating the mechanical properties of liposarcoma-derived EVs as a function of their size. Our study includes extracting morphological data of EVs from a large dataset of 432 TEM images, with images containing single to multiple EVs, and implementing the thin-shell deformation theory. We estimated the elastic modulus, E = 0.16 ± 0.02 MPa (mean±SE) for small EVs (sEVs; 30-150 nm) and E = 0.17 ± 0.03 MPa (mean±SE) for large EVs (lEVs; >150 nm). To our knowledge, this is the first report on the mechanical property estimation of LPS-derived EVs and has the potential to establish a relationship between EV size and EV mechanical properties.

Edible Plant-Derived Extracellular Vesicles for Oral mRNA Vaccine Delivery

Nucleic acid delivery through extracellular vesicles (EVs) is a well-preserved evolutionary mechanism in all life kingdoms including eukaryotes, prokaryotes, and plants. EVs naturally allow horizontal transfer of native as well as exogenous functional mRNAs, which once incorporated in EVs are protected from enzymatic degradation. This observation has prompted researchers to investigate whether EVs from different sources, including plants, could be used for vaccine delivery. Several studies using human or bacterial EVs expressing mRNA or recombinant SARS-CoV-2 proteins showed induction of a humoral and cell mediated immune response. Moreover, EV-based vaccines presenting the natural configuration of viral antigens have demonstrated advantages in conferring long-lasting immunization and lower toxicity than synthetic nanoparticles. Edible plant-derived EVs were shown to be an alternative to human EVs for vaccine delivery, especially via oral administration. EVs obtained from orange juice (oEVs) loaded with SARS-CoV-2 mRNAs protected their cargo from enzymatic degradation, were stable at room temperature for one year, and were able to trigger a SARS-CoV-2 immune response in mice. Lyophilized oEVs containing the S1 mRNA administered to rats via gavage induced a specific humoral immune response with generation of blocking antibodies, including IgA and Th1 lymphocyte activation. In conclusion, mRNA-containing oEVs could be used for developing new oral vaccines due to optimal mucosal absorption, resistance to stress conditions, and ability to stimulate a humoral and cellular immune response.

Extracellular Vesicles and Their Role in Lung Infections

Lung infections are one of the most common causes of death and morbidity worldwide. Both bacterial and viral lung infections cause a vast number of infections with varying severities. Extracellular vesicles (EVs) produced by different cells due to infection in the lung have the ability to modify the immune system, leading to either better immune response or worsening of the disease. It has been shown that both bacteria and viruses have the ability to produce their EVs and stimulate the immune system for that. In this review, we investigate topics from EV biogenesis and types of EVs to lung bacterial and viral infections caused by various bacterial species. Mycobacterium tuberculosis, Staphylococcus aureus, and Streptococcus pneumoniae infections are covered intensively in this review. Moreover, various viral lung infections, including SARS-CoV-2 infections, have been depicted extensively. In this review, we focus on eukaryotic-cell-derived EVs as an important component of disease pathogenesis. Finally, this review holds high novelty in its findings and literature review. It represents the first time to cover all different information on immune-cell-derived EVs in both bacterial and viral lung infections.

Genomic communication via circulating extracellular vesicles and long-term health consequences of COVID-19

COVID-19 continues to affect an unprecedented number of people with the emergence of new variants posing a serious challenge to global health. There is an expansion of knowledge in understanding the pathogenesis of Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and the impact of the acute disease on multiple organs. In addition, growing evidence reports that the impact of COVID-19 on different organs persists long after the recovery phase of the disease, leading to long-term consequences of COVID-19. These long-term consequences involve pulmonary as well as extra-pulmonary sequelae of the disease. Noteably, recent research has shown a potential association between COVID-19 and change in the molecular cargo of extracellular vesicles (EVs). EVs are vesicles released by cells and play an important role in cell communication by transfer of bioactive molecules between cells. Emerging evidence shows a strong link between EVs and their molecular cargo, and regulation of metabolism in health and disease. This review focuses on current knowledge about EVs and their potential role in COVID-19 pathogenesis, their current and future implications as tools for biomarker and therapeutic development and their possible effects on long-term impact of COVID-19.

Impact of COVID-19 on pregnant women's health: Consequences in obstetrics two years after the pandemic

The pandemic linked to SARS-CoV-2 has profoundly disrupted the health systems and many studies have led to a better understanding of this virus, which is responsible for severe disease, particularly during pregnancy. Pregnancy is a risk factor for severe COVID-19. Term of pregnancy and vaccination status is the main risk factor in addition to classic comorbidities like general population. COVID-19 during pregnancy is responsible for more maternal death, stillbirth, pre-eclampsia spontaneous and induced prematurity. Vaccination is therefore strongly recommended for pregnant patients. In addition, the COVID-19 pandemic has highlighted a psychological and social dimension that should not be neglected in the management of a pregnant patient. Correlation between immunological changes and clinical impact are described in this review. Many conclusions can now be made and are summarized in this article in order to discuss possible future research.

Clinical Prospect of Mesenchymal Stromal/Stem Cell-Derived Extracellular Vesicles in Kidney Disease: Challenges and the Way Forward

Kidney disease is a growing public health problem worldwide, including both acute and chronic forms. Existing therapies for kidney disease target various pathogenic mechanisms; however, these therapies only slow down the progression of the disease rather than offering a cure. One of the potential and emerging approaches for the treatment of kidney disease is mesenchymal stromal/stem cell (MSC) therapy, shown to have beneficial effects in preclinical studies. In addition, extracellular vesicles (EVs) released by MSCs became a potent cell-free therapy option in various preclinical models of kidney disease due to their regenerative, anti-inflammatory, and immunomodulatory properties. However, there are scarce clinical data available regarding the use of MSC-EVs in kidney pathologies. This review article provides an outline of the renoprotective effects of MSC-EVs in different preclinical models of kidney disease. It offers a comprehensive analysis of possible mechanisms of action of MSC-EVs with an emphasis on kidney disease. Finally, on the journey toward the implementation of MSC-EVs into clinical practice, we highlight the need to establish standardized methods for the characterization of an EV-based product and investigate the adequate dosing, safety, and efficacy of MSC-EVs application, as well as the development of suitable potency assays.

Intrinsic factors behind long-COVID: I. Prevalence of the extracellular vesicles

It can be argued that the severity of COVID-19 has decreased in many countries. This could be a result of the broad coverage of the population by vaccination campaigns, which often reached an almost compulsory status in many places. Furthermore, significant roles were played by the multiple mutations in the body of the virus, which led to the emergence of several new SARS-CoV-2 variants with enhanced infectivity but dramatically reduced pathogenicity. However, the challenges associated with the development of various side effects and their persistence for long periods exceeding 20 months as a result of the SARS-CoV-2 infection, or taking available vaccines against it, are spreading horizontally and vertically in number and repercussions. For example, the World Health Organization announced that there are more than 17 million registered cases of long-COVID (also known as post-COVID syndrome) in the European Union countries alone. Furthermore, by using the PubMed search engine, one can find that more than 10 000 articles have been published focusing exclusively on long-COVID. In light of these enormous and ever-increasing numbers of cases and published articles, most of which are descriptive of the various long-COVID symptoms, the need to know the reasons behind this phenomenon raises several important questions. Is long-COVID caused by the continued presence of the virus or one/several of its components in the recovering individual body for long periods of time, which urges the body to respond in a way that leads to long-COVID development? Or are there some latent and limited reasons related to the recovering patients themselves? Or is it a sum of both? Many observations support a positive answer to the first question, whereas others back the second question but typically without releasing a fundamental reason/signal behind it. Whatever the answer is, it seems that the real reasons behind this widespread phenomenon remain unclear. This report opens a series of articles, in which we will try to shed light on the underlying causes that could be behind the long-COVID phenomenon.

Plant-Derived Extracellular Vesicles as a Delivery Platform for RNA-Based Vaccine: Feasibility Study of an Oral and Intranasal SARS-CoV-2 Vaccine

Plant-derived extracellular vesicles (EVs) may represent a platform for the delivery of RNA-based vaccines, exploiting their natural membrane envelope to protect and deliver nucleic acids. Here, EVs extracted from orange (Citrus sinensis) juice (oEVs) were investigated as carriers for oral and intranasal SARS-CoV-2 mRNA vaccine. oEVs were efficiently loaded with different mRNA molecules (coding N, subunit 1 and full S proteins) and the mRNA was protected from degrading stress (including RNase and simulated gastric fluid), delivered to target cells and translated into protein. APC cells stimulated with oEVs loaded with mRNAs induced T lymphocyte activation in vitro. The immunization of mice with oEVs loaded with S1 mRNA via different routes of administration including intramuscular, oral and intranasal stimulated a humoral immune response with production of specific IgM and IgG blocking antibodies and a T cell immune response, as suggested by IFN-γ production by spleen lymphocytes stimulated with S peptide. Oral and intranasal administration also triggered the production of specific IgA, the mucosal barrier in the adaptive immune response. In conclusion, plant-derived EVs represent a useful platform for mRNA-based vaccines administered not only parentally but also orally and intranasally.

Extracellular vesicle proteomics and phosphoproteomics identify pathways for increased risk in patients hospitalized with COVID-19 and type 2 diabetes mellitus

Recent studies suggest that extracellular vesicles (EVs) play a role in the pathogenesis of SARS-CoV-2 infection and the severity of COVID-19. However, their role in the interaction between COVID-19 and type 2 diabetes (T2D) has not been addressed. Here, we characterized the circulating EV proteomic and phosphoproteomic landscape in patients with and without T2D hospitalized with COVID-19 or non-COVID-19 acute respiratory illness (RSP). We detected differentially expressed protein and phosphoprotein signatures that effectively characterized the study groups. The trio of immunomodulatory and coagulation proteins C1QA, C1QB, and C1QC appeared to be a central cluster in both the COVID-19 and T2D functional networks. PKCβ appeared to be retained in cells by being diverted from EV pathways and contribute to the COVID-19 and T2D interaction via a PKC/BTK/TEC axis. EV-shuttled CASP3 and ROCK1 appeared to be coregulated and likely contribute to disease interactions in patients with COVID-19 and T2D. Predicted activation of AMPK, MAPK, and SYK appeared to also play important roles driving disease interaction. These results suggest that activated cellular kinases (i.e., PKC, AMPK, MAPK, and SYK) and multiple EV-shuttled kinases (i.e., PKCβ, BTK, TEC, MAP2K2, and ROCK1) may play key roles in severe COVID-19, particularly in patients with comorbid diabetes.

Isolation of native EVs from primary biofluids-Free-flow electrophoresis as a novel approach to purify ascites-derived EVs

Although extracellular vesicles (EVs) have been extensively characterized, efficient purification methods, especially from primary biofluids, remain challenging. Here we introduce free-flow electrophoresis (FFE) as a novel approach for purifying EVs from primary biofluids, in particular from the peritoneal fluid (ascites) of ovarian cancer patients. FFE represents a versatile, fast, matrix-free approach for separating different analytes with inherent differences in charge density and/or isoelectric point (pI). Using a series of buffered media with different pH values allowed us to collect 96 fractions of ascites samples. To characterize the composition of the individual fractions, we used state-of-the-art methods such as nanoflow and imaging flow cytometry (nFCM and iFCM) in addition to classical approaches. Of note, tetraspanin-positive events measured using nFCM were enriched in a small number of distinct fractions. This observation was corroborated by Western blot analysis and electron microscopy, demonstrating only minor contamination with soluble proteins and lipid particles. In addition, these gently purified EVs remain functional. Thus, FFE represents a new, efficient and fast method for separating native and highly purified EVs from complicated primary samples.