Circulating Extracellular Vesicles in Human Disease

Cross-species modeling of muscular dystrophy in Caenorhabditis elegans using patient-derived extracellular vesicles

Reliable disease models are critical for medicine advancement. Here, we established a versatile human disease model system using patient-derived extracellular vesicles (EVs), which transfer a pathology-inducing cargo from a patient to a recipient naïve model organism. As a proof of principle, we applied EVs from the serum of patients with muscular dystrophy to Caenorhabditis elegans and demonstrated their capability to induce a spectrum of muscle pathologies, including lifespan shortening and robust impairment of muscle organization and function. This demonstrates that patient-derived EVs can deliver disease-relevant pathologies between species and can be exploited for establishing novel and personalized models of human disease. Such models can potentially be used for disease diagnosis, prognosis, analyzing treatment responses, drug screening and identification of the disease-transmitting cargo of patient-derived EVs and their cellular targets. This system complements traditional genetic disease models and enables modeling of multifactorial diseases and of those not yet associated with specific genetic mutations.

Advances in the regulation of adipogenesis and lipid metabolism by exosomal ncRNAs and their role in related metabolic diseases

Exosomes are membrane-bound extracellular vesicles released following the fusion of multivesicular bodies (MVBs) with the cell membrane. Exosomes transport diverse molecules, including proteins, lipids, DNA and RNA, and regulate distant intercellular communication. Noncoding RNA (ncRNAs) carried by exosomes regulate cell-cell communication in tissues, including adipose tissue. This review summarizes the action mechanisms of ncRNAs carried by exosomes on adipocyte differentiation and modulation of adipogenesis by exosomal ncRNAs. This study aims to provide valuable insights for developing novel therapeutics.

Identifying high-grade serous ovarian carcinoma-specific extracellular vesicles by polyketone-coated nanowires

Cancer cell-derived extracellular vesicles (EVs) have unique protein profiles, making them promising targets as disease biomarkers. High-grade serous ovarian carcinoma (HGSOC) is the deadly subtype of epithelial ovarian cancer, and we aimed to identify HGSOC-specific membrane proteins. Small EVs (sEVs) and medium/large EVs (m/lEVs) from cell lines or patient serum and ascites were analyzed by LC-MS/MS, revealing that both EV subtypes had unique proteomic characteristics. Multivalidation steps identified FRα, Claudin-3, and TACSTD2 as HGSOC-specific sEV proteins, but m/lEV-associated candidates were not identified. In addition, for using a simple-to-use microfluidic device for EV isolation, polyketone-coated nanowires (pNWs) were developed, which efficiently purify sEVs from biofluids. Multiplexed array assays of sEVs isolated by pNW showed specific detectability in cancer patients and predicted clinical status. In summary, the HGSOC-specific marker detection by pNW are a promising platform as clinical biomarkers, and these insights provide detailed proteomic aspects of diverse EVs in HGSOC patients.

Epicardial adipocytes in the pathogenesis of atrial fibrillation: An update on basic and translational studies

Epicardial adipose tissue (EAT) is an endocrine organ containing a host of cell types and undoubtedly serving a multitude of important physiologic functions. Aging and obesity cause hypertrophy of EAT. There is great interest in the possible connection between EAT and cardiovascular disease, in particular, atrial fibrillation (AF). Increased EAT is independently associated with AF and adverse events after AF ablation (e.g., recurrence of AF, and stroke). In general, the amount of EAT correlates with BMI or visceral adiposity. Yet on a molecular level, there are similarities and differences between epicardial and abdominal visceral adipocytes. In comparison to subcutaneous adipose tissue, both depots are enriched in inflammatory cells and chemokines, even in normal conditions. On the other hand, in comparison to visceral fat, epicardial adipocytes have an increased rate of fatty acid release, decreased size, and increased vascularity. Several studies have described an association between fibrosis of EAT and fibrosis of the underlying atrial myocardium. Others have discovered paracrine factors released from EAT that could possibly mediate this association. In addition to the adjacent atrial cardiomyocytes, EAT contains a robust stromal-vascular fraction and surrounds the ganglionic plexi of the cardiac autonomic nervous system (cANS). The importance of the cANS in the pathogenesis of atrial fibrillation is well known, and it is quite likely that there is feedback between EAT and the cANS. This complex interplay may be crucial to the maintenance of normal sinus rhythm or the development of atrial fibrillation. The extent the adipocyte is a microcosm of metabolic health in the individual patient may determine which is the predominant rhythm.

Alpha-2-macroglobulin as a novel diagnostic biomarker for human bladder cancer in urinary extracellular vesicles

Extracellular vesicles (EVs) derived from urine are promising tools for the diagnosis of urogenital cancers. Urinary EVs (uEVs) are considered potential biomarkers for bladder cancer (BC) because urine is in direct contact with the BC tumor microenvironment and thus reflects the current state of the disease. However, challenges associated with the effective isolation and analysis of uEVs complicate the clinical detection of uEV-associated protein biomarkers. Herein, we identified uEV-derived alpha-2-macroglobulin (a2M) as a novel diagnostic biomarker for BC through comparative analysis of uEVs obtained from patients with BC pre- and post-operation using an antibody array. Furthermore, enzyme-linked immunosorbent assay of uEVs isolated from patients with BC (n=60) and non-cancer control subjects (n=23) validated the significant upregulation of a2M expression in patient uEVs (p<0.0001). There was no significant difference in whole urine a2M levels between patients with BC and controls (p=0.317). We observed that compared to classical differential centrifugation, ExoDisc, a centrifugal microfluidic tangential flow filtration device, was a significantly more effective separation method for uEV protein analysis. We expect that our approach for EV analysis will provide an efficient route for the identification of clinically meaningful uEV-based biomarkers for cancer diagnosis.

Adipose-Derived Extracellular Vesicles: Systemic Messengers and Metabolic Regulators in Health and Disease

Adipose tissue is comprised of a heterogeneous population of cells that co-operate to perform diverse physiological roles including endocrine-related functions. The endocrine role of adipose tissue enables it to communicate nutritional and health cues to other organs, such as the liver, muscle, and brain, in order to regulate appetite and whole body metabolism. Adipose tissue dysfunction, which is often observed in obesity, is associated with changes in the adipose secretome, which can subsequently contribute to disease pathology. Indeed, secreted bioactive factors released from adipose tissue contribute to metabolic homeostasis and likely play a causal role in disease; however, what constitutes the entirety of the adipose tissue secretome is still poorly understood. Recent advances in nanotechnology have advanced this field substantially and have led to the identification of small, secreted particles known as extracellular vesicles (EVs). These small nano-sized lipid envelopes are released by most cell types and are capable of systemically delivering bioactive molecules, such as nucleic acids, proteins, and lipids. EVs interact with target cells to deliver specific cargo that can then elicit effects in various tissues throughout the body. Adipose tissue has recently been shown to secrete EVs that can communicate with the periphery to maintain metabolic homeostasis, or under certain pathological conditions, drive disease. In this review, we discuss the current landscape of adipose tissue-derived EVs, with a focus on their role in the regulation of metabolic homeostasis and disease pathology.

The role of glial cells in multiple sclerosis disease progression

Despite the development of highly effective treatments for relapsing-remitting multiple sclerosis (MS), limited progress has been made in addressing primary progressive or secondary progressive MS, both of which lead to loss of oligodendrocytes and neurons and axons, and to irreversible accumulation of disability. Neuroinflammation is central to all forms of MS. The current effective therapies for relapsing-remitting MS target the peripheral immune system; these treatments, however, have repeatedly failed in progressive MS. Greater understanding of inflammation driven by CNS-resident cells - including astrocytes and microglia - is, therefore, required to identify novel potential therapeutic opportunities. Advances in imaging, biomarker analysis and genomics suggest that microglia and astrocytes have central roles in the progressive disease process. In this Review, we provide an overview of the involvement of astrocytes and microglia at major sites of pathology in progressive MS. We discuss current and future therapeutic approaches to directly target glial cells, either to inhibit pathogenic functions or to restore homeostatic functions lost during the course of the disease. We also discuss how bidirectional communication between astrocytes and microglia needs to be considered, as therapeutic targeting of one is likely to alter the functions of the other.

A simple immunoassay for extracellular vesicle liquid biopsy in microliters of non-processed plasma

BACKGROUND

Extracellular vesicles (EVs), released by most cell types, provide an excellent source of biomarkers in biological fluids. However, in order to perform validation studies and screenings of patient samples, it is still necessary to develop general techniques permitting rapid handling of small amounts of biological samples from large numbers of donors.

RESULTS

Here we describe a method that, using just a few microliters of patient's plasma, identifies tumour markers exposed on EVs. Studying physico-chemical properties of EVs in solution, we demonstrate that they behave as stable colloidal suspensions and therefore, in immunocapture assays, many of them are unable to interact with a stationary functionalised surface. Using flocculation methods, like those used to destabilize colloids, we demonstrate that cationic polymers increase EV ζ-potential, diameter, and sedimentation coefficient and thus, allow a more efficient capture on antibody-coated surfaces by both ELISA and bead-assisted flow cytometry. These findings led to optimization of a protocol in microtiter plates allowing effective immunocapture of EVs, directly in plasma without previous ultracentrifugation or other EV enrichment. The method, easily adaptable to any laboratory, has been validated using plasma from lung cancer patients in which the epithelial cell marker EpCAM has been detected on EVs.

CONCLUSIONS

This optimized high throughput, easy to automate, technology allows screening of large numbers of patients to phenotype tumour markers in circulating EVs, breaking barriers for the validation of proposed EV biomarkers and the discovery of new ones.

Antibiotic prophylaxis as a quality of care indicator: does it help in the fight against surgical site infections following fragility hip fractures?

INTRODUCTION

Fragility hip fractures are associated with increased morbidity, mortality, and costs. To improve patient care, quality indicator programs were introduced. Yet, the efficacy of these programs and specific quality indicators are questioned. We aimed to determine whether defining prophylactic pre-surgical antibiotic treatment as a quality indicator affected hip fracture outcomes.

MATERIALS AND METHODS

A retrospective study comparing consecutive patients, 65 years and older, who were operated for fragility hip fractures between 01/01/2011 and 30/06/2016, before and after the prophylactic pre-surgical antibiotic treatment quality indicator, which was introduced in 01/2014. Primary outcomes were 1-year surgical site infections (SSI). Secondary outcomes were meeting the quality index and mortality rates, either within a hospital or during the first post-operative year.

RESULTS

904 patients, ages 82.5 ± 7.2 years were operated for fragility hip fractures. 403 patients presented before the antibiotic prophylaxis quality indicator, and 501 following its administration. Patients demographics were comparable. In the pre-quality indicator period, documentation of prophylactic antibiotic treatment was lacking. Only 19.6% had a record for antibiotic administration in their surgical records and for merely 10.4% the type of antibiotic was stated. However, in the post-quality indicator period, 97.0% of patients had a registered prophylactic antibiotic regimen in the hour preceding the surgical incision (p  < 0.001). Post-operative SSI rates were equivalent, and as were in-hospital infections, mortality and recurrent hospitalizations CONCLUSIONS: The introduction of the pre-operative antibiotic treatment quality indicator increased the documentation of antibiotic administration yet failed to influence the incidence of post-operative orthopaedic and medical infections in fragility hip fracture patients.

Role of Extracellular Vesicles as Potential Diagnostic and/or Therapeutic Biomarkers in Chronic Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the first cause of death worldwide. In recent years, there has been great interest in the analysis of extracellular vesicles (EVs), including exosomes and microparticles, as potential mediators of biological communication between circulating cells/plasma and cells of the vasculature. Besides their activity as biological effectors, EVs have been also investigated as circulating/systemic biomarkers in different acute and chronic CVDs. In this review, the role of EVs as potential diagnostic and prognostic biomarkers in chronic cardiovascular diseases, including atherosclerosis (mainly, peripheral arterial disease, PAD), aortic stenosis (AS) and aortic aneurysms (AAs), will be described. Mechanistically, we will analyze the implication of EVs in pathological processes associated to cardiovascular remodeling, with special emphasis in their role in vascular and valvular calcification. Specifically, we will focus on the participation of EVs in calcium accumulation in the pathological vascular wall and aortic valves, involving the phenotypic change of vascular smooth muscle cells (SMCs) or valvular interstitial cells (IC) to osteoblast-like cells. The knowledge of the implication of EVs in the pathogenic mechanisms of cardiovascular remodeling is still to be completely deciphered but there are promising results supporting their potential translational application to the diagnosis and therapy of different CVDs.

In Vivo Visualized Tracking of Tumor-Derived Extracellular Vesicles Using CRISPR-Cas9 System

Introduction: Tumor extracellular vesicles (EVs) and their relevance to various processes of tumor growth have been vigorously investigated over the past decade. However, obtaining direct evidence of spontaneous EV transfer in vivo remains challenging. In our previous study, a single-guide RNA (sgRNA): Cas9 ribonucleoprotein complex, which can efficiently delete target genes, was delivered into recipient cells using an engineered EV. Aim: Applying this newly discovered exosomal bio-cargo to track the uptake and distribution of tumor EVs. Methods: Tumor cells of interest were engineered to express and release the sgRNA:Cas9 complex, and a reporter cell/system containing STOP-fluorescent protein (FP) elements was also generated. EV-delivered Cas9 proteins from donor cells were programmed by a pair of sgRNAs to completely delete a blockade sequence and, in turn, recuperated the expression of FP in recipient reporter cells. Thus, fluorescently illuminated cells indicate the uptake of EVs. To improve the efficiency and sensitivity of this tracking system in vivo, we optimized the sgRNA design, which could more efficiently trigger the expression of reporter proteins. Results: We demonstrated the EV-mediated crosstalk between tumor cells, and between tumor cells and normal cells in vitro. In vivo, we showed that intravenously administered EVs can be taken up by the liver. Moreover, we showed that EVs derived from melanoma xenografts in vivo preferentially target the brain and liver. This distribution resembles the manifestation of organotrophic metastasis of melanoma. Conclusion: This study provides an alternative tool to study the distribution and uptake of tumor EVs.

Extracellular vesicles: General features and usefulness in diagnosis and therapeutic management of colorectal cancer

In the world, among all type of cancers, colorectal cancer (CRC) is the third most commonly diagnosed in males and the second in females. In most of cases, (RP1) patients’ prognosis limitation with malignant tumors can be attributed to delayed diagnosis of the disease. Identification of patients with early-stage disease leads to more effective therapeutic interventions. Therefore, new screening methods and further innovative treatment approaches are mandatory as they may lead to an increase in progression-free and overall survival rates. For the last decade, the interest in extracellular vesicles (EVs) research has exponentially increased as EVs generation appears to be a universal feature of every cell that is strongly involved in many mechanisms of cell-cell communication either in physiological or pathological situations. EVs can cargo biomolecules, such as lipids, proteins, nucleic acids and generate transmission signal through the intercellular transfer of their content. By this mechanism, tumor cells can recruit and modify the adjacent and systemic microenvironment to support further invasion and dissemination. This review intends to cover the most recent literature on the role of EVs production in colorectal normal and cancer tissues. Specific attention is paid to the use of EVs for early CRC diagnosis, follow-up, and prognosis as EVs have come into the spotlight of research as a high potential source of ‘liquid biopsies’. The use of EVs as new targets or nanovectors as drug delivery systems for CRC therapy is also summarized.

Adipose Tissue Macrophages Modulate Obesity-Associated β Cell Adaptations through Secreted miRNA-Containing Extracellular Vesicles

Obesity induces an adaptive expansion of β cell mass and insulin secretion abnormality. Expansion of adipose tissue macrophages (ATMs) is a hallmark of obesity. Here, we assessed a novel role of ATMs in mediating obesity-induced β cell adaptation through the release of miRNA-containing extracellular vesicles (EVs). In both in vivo and in vitro experiments, we show that ATM EVs derived from obese mice notably suppress insulin secretion and enhance β cell proliferation. We also observed similar phenotypes from human islets after obese ATM EV treatment. Importantly, depletion of miRNAs blunts the effects of obese ATM EVs, as evidenced by minimal effects of obese DicerKO ATM EVs on β cell responses. miR-155 is a highly enriched miRNA within obese ATM EVs and miR-155 overexpressed in β cells impairs insulin secretion and enhances β cell proliferation. In contrast, knockout of miR-155 attenuates the regulation of obese ATM EVs on β cell responses. We further demonstrate that the miR-155-Mafb axis plays a critical role in controlling β cell responses. These studies show a novel mechanism by which ATM-derived EVs act as endocrine vehicles delivering miRNAs and subsequently mediating obesity-associated β cell adaptation and dysfunction.

Flood Control: How Milk-Derived Extracellular Vesicles Can Help to Improve the Intestinal Barrier Function and Break the Gut-Joint Axis in Rheumatoid Arthritis

Many studies provided compelling evidence that extracellular vesicles (EVs) are involved in the regulation of the immune response, acting as both enhancers and dampeners of the immune system, depending on the source and type of vesicle. Research, including ours, has shown anti-inflammatory effects of milk-derived EVs, using human breast milk as well as bovine colostrum and store-bought pasteurized cow milk, in in vitro systems as well as therapeutically in animal models. Although it is not completely elucidated which proteins and miRNAs within the milk-derived EVs contribute to these immunosuppressive capacities, one proposed mechanism of action of the EVs is via the modulation of the crosstalk between the (intestinal) microbiome and their host health. There is increasing awareness that the gut plays an important role in many inflammatory diseases. Enhanced intestinal leakiness, dysbiosis of the gut microbiome, and bowel inflammation are not only associated with intestinal diseases like colitis and Crohn's disease, but also characteristic for systemic inflammatory diseases such as lupus, multiple sclerosis, and rheumatoid arthritis (RA). Strategies to target the gut, and especially its microbiome, are under investigation and hold a promise as a therapeutic intervention for these diseases. The use of milk-derived EVs, either as stand-alone drug or as a drug carrier, is often suggested in recent years. Several research groups have studied the tolerance and safety of using milk-derived EVs in animal models. Due to its composition, milk-derived EVs are highly biocompatible and have limited immunogenicity even cross species. Furthermore, it has been demonstrated that milk-derived EVs, when taken up in the gastro-intestinal tract, stay intact after absorption, indicating excellent stability. These characteristics make milk-derived EVs very suitable as drug carriers, but also by themselves, these EVs already have a substantial immunoregulatory function, and even without loading, these vesicles can act as therapeutics. In this review, we will address the immunomodulating capacity of milk-derived EVs and discuss their potential as therapy for RA patients.

Review criteria

The search terms "extracellular vesicles", "exosomes", "microvesicles", "rheumatoid arthritis", "gut-joint axis", "milk", and "experimental arthritis" were used. English-language full text papers (published between 1980 and 2021) were identified from PubMed and Google Scholar databases. The reference list for each paper was further searched to identify additional relevant articles.

Analysis of Amount, Size, Protein Phenotype and Molecular Content of Circulating Extracellular Vesicles Identifies New Biomarkers in Multiple Myeloma

INTRODUCTION

Extracellular vesicles (EVs) are naturally secreted cellular lipid bilayer particles, which carry a selected molecular content. Owing to their systemic availability and their role in tumor pathogenesis, circulating EVs (cEVs) can be a valuable source of new biomarkers useful for tumor diagnosis, prognostication and monitoring. However, a precise approach for isolation and characterization of cEVs as tumor biomarkers, exportable in a clinical setting, has not been conclusively established.

METHODS

We developed a novel and laboratory-made procedure based on a bench centrifuge step which allows the isolation of serum cEVs suitable for subsequent characterization of their size, amount and phenotype by nanoparticle tracking analysis, microscopy and flow cytometry, and for nucleic acid assessment by digital PCR.

RESULTS

Applied to blood from healthy subjects (HSs) and tumor patients, our approach permitted from a small volume of serum (i) the isolation of a great amount of EVs enriched in small vesicles free from protein contaminants; (ii) a suitable and specific cell origin identification of EVs, and (iii) nucleic acid content assessment. In clonal plasma cell malignancy, like multiple myeloma (MM), our approach allowed us to identify specific MM EVs, and to characterize their size, concentration and microRNA content allowing significant discrimination between MM and HSs. Finally, EV associated biomarkers correlated with MM clinical parameters.

CONCLUSION

Overall, our cEV based procedure can play an important role in malignancy biomarker discovery and then in real-time tumor monitoring using minimal invasive samples. From a practical point of view, it is smart (small sample volume), rapid (two hours), easy (no specific expertise required) and requirements are widely available in clinical laboratories.

The Role of Circulating Biomarkers in Peripheral Arterial Disease

Peripheral arterial disease (PAD) of the lower extremities is a chronic illness predominantly of atherosclerotic aetiology, associated to traditional cardiovascular (CV) risk factors. It is one of the most prevalent CV conditions worldwide in subjects >65 years, estimated to increase greatly with the aging of the population, becoming a severe socioeconomic problem in the future. The narrowing and thrombotic occlusion of the lower limb arteries impairs the walking function as the disease progresses, increasing the risk of CV events (myocardial infarction and stroke), amputation and death. Despite its poor prognosis, PAD patients are scarcely identified until the disease is advanced, highlighting the need for reliable biomarkers for PAD patient stratification, that might also contribute to define more personalized medical treatments. In this review, we will discuss the usefulness of inflammatory molecules, matrix metalloproteinases (MMPs), and cardiac damage markers, as well as novel components of the liquid biopsy, extracellular vesicles (EVs), and non-coding RNAs for lower limb PAD identification, stratification, and outcome assessment. We will also explore the potential of machine learning methods to build prediction models to refine PAD assessment. In this line, the usefulness of multimarker approaches to evaluate this complex multifactorial disease will be also discussed.

Native and Bioengineered Exosomes for Ischemic Stroke Therapy

Exosomes are natural cells-derived vesicles, which are at the forefront toward clinical success for various diseases, including cerebral ischemia. Exosomes mediate cell-to-cell communication in different brain cells during both physiological and pathological conditions. Exosomes are an extensively studied type of extracellular vesicle, which are considered to be the best alternative for stem cell-based therapy. They can be secreted by various cell types and have unique biological properties. Even though native exosomes have potential for ischemic stroke therapy, some undesirable features prevent their success in clinical applications, including a short half-life, poor targeting property, low concentration at the target site, rapid clearance from the lesion region, and inefficient payload. In this review, we highlight exosome trafficking and cellular uptake and survey the latest discoveries in the context of exosome research as the best fit for brain targeting owing to its natural brain-homing abilities. Furthermore, we overview the methods by which researchers have bioengineered exosomes (BioEng-Exo) for stroke therapy. Finally, we summarize studies in which exosomes were bioengineered by a third party for stroke recovery. This review provides up-to-date knowledge about the versatile nature of exosomes with a special focus on BioEng-Exo for ischemic stroke. Standard exosome bioengineering techniques are mandatory for the future and will lead exosomes toward clinical success for stroke therapy.

Circulating Exosomes From Patients With Graves' Disease Induce an Inflammatory Immune Response

Exosomes are extracellular vesicles that can participate in autoimmune diseases. The purpose of this study was to explore whether circulating exosomes are involved in Graves' disease (GD) pathogenesis. In this study, serum exosomes were extracted from 26 healthy controls (HC-EXO), 26 GD patients (GD-EXO), and 7 Graves' ophthalmopathy patients (GO-EXO). For each group, the total protein content was detected, and thyrotropin receptor, insulin-like growth factor 1 receptor (IGF-1R), heat shock protein 60 (HSP60), and cluster of differentiation (CD) 63 expression were analyzed by Western blotting (WB). Healthy volunteer-derived peripheral blood mononuclear cells (PBMCs) and HC-EXO or GD-EXO were cocultured for 24 h, and immunofluorescence was used to observe the locations of the exosomes and toll-like receptor (TLR) 2/3. CD11c+TLR2+ and CD11c+TLR3+ cell percentages were determined by flow cytometry. Myeloid differentiation factor 88 (MyD88), toll/interleukin (IL)-1 receptor domain-containing adaptor inducing interferon-β (TRIF) and p-P65 expression were analyzed by WB. IL-6 and IL-1β supernatant levels were detected using enzyme-linked immunosorbent assay. The results showed that the total protein concentration was similar among GD-EXO, GO-EXO, and HC-EXO. IGF-1R and HSP60 expression was significantly higher in GD-EXO and GO-EXO than in HC-EXO. After coculturing PBMCs with GD-EXO or HC-EXO for 24 h, GD-EXO could bind to TLR2/3. GD-EXO significantly increased CD11c+TLR2+ and CD11c+TLR3+ cell percentages; MyD88, TRIF, and p-P65 protein expression; and IL-6 and IL-1β levels. In conclusion, we first demonstrated that GD-EXO and GO-EXO highly expressed IGF-1R and HSP60. GD-EXO may induce an inflammatory response through the TLR/NF-κB signaling pathway and be involved in the pathogenesis of GD.

Emerging Roles of Urine-Derived Components for the Management of Bladder Cancer: One Man's Trash Is Another Man's Treasure

Simple Summary

Urinary bladder cancer (UBC) is one of the most common and deadly cancers worldwide, with many patients not responding to chemotherapy, or presenting with serious adverse effects after chemotherapy. Yet, current bench side assays provide limited accuracy for predicting therapeutic response to chemotherapeutic drugs. The aim of this review is to demonstrate the potential of urinary-derived extracellular vesicles and UBC-organoids to serve as predictive biomarkers for this cancer. Specifically, molecular subtyping of urine-derived extracellular vesicles has the potential to provide insights into the molecular stratification of the tumor, while urinary organoids will allow for individualized chemotherapy testing in the context of precision medicine.

Abstract

Urinary bladder cancer (UBC) is the most common malignancy of the urinary tract in humans, with an estimated global prevalence of 1.1 million cases over 5 years. Because of its high rates of recurrence and resistance to chemotherapy, UBC is one of the most expensive cancers to treat, resulting in significant health care costs. The development of innovative molecular and cellular tools is necessary to refine patient stratification and help predict response to treatment. Urine is an underused resource of biological components shed from bladder tumors, such as exfoliated cells and extracellular vesicles, that could serve as molecular fingerprints and provide valuable biological insights into tumor phenotype and mechanisms of resistance to chemotherapy. Additionally, characterization of urine-derived extracellular vesicles and cells could be used as reliable biomarkers for prediction of response to neoadjuvant therapy.

Extracellular Vesicles from Airway Secretions: New Insights in Lung Diseases

Lung diseases (LD) are one of the most common causes of death worldwide. Although it is known that chronic airway inflammation and excessive tissue repair are processes associated with LD such as asthma, chronic obstructive pulmonary disease (COPD) or idiopathic pulmonary fibrosis (IPF), their specific pathways remain unclear. Extracellular vesicles (EVs) are heterogeneous nanoscale membrane vesicles with an important role in cell-to-cell communication. EVs are present in general biofluids as plasma or urine but also in secretions of the airway as bronchoalveolar lavage fluid (BALF), induced sputum (IS), nasal lavage (NL) or pharyngeal lavage. Alterations of airway EV cargo could be crucial for understanding LD. Airway EVs have shown a role in the pathogenesis of some LD such as eosinophil increase in asthma, the promotion of lung cancer in vitro models in COPD and as biomarkers to distinguishing IPF in patients with diffuse lung diseases. In addition, they also have a promising future as therapeutics for LD. In this review, we focus on the importance of airway secretions in LD, the pivotal role of EVs from those secretions on their pathophysiology and their potential for biomarker discovery.

Detection of Pancreatic Ductal Adenocarcinoma by A qPCR-based Normalizer-free Circulating Extracellular Vesicles RNA Signature

Background: Pancreatic ductal adenocarcinoma (PDAC) is difficult to diagnose and many efforts have been made to evaluate EVs-derived RNAs as biomarkers to predict PDAC. However, lack of robust internal references largely limited their clinical application. Here we proposed an RNA ratio-based, normalizer-free algorithm to quantitate EVs-derived RNAs in PDAC. Methods: Differentially expressed RNAs in the training group were identified using "limma" package. The ratio of any two candidate RNAs in the same sample was calculated and used as a new biomarker. LASSO regression was performed to build prediction models based on those RNA ratios. RNA-seq data of 116 plasma samples and RT-qPCR data of 111 plasma samples were used for internal and external validation, separately. Three algorithms (lasso regression, logistic regression, and SVM) were compared to improve the performance of this RNA signature. Results: We developed an RNA-ratio based prediction model which comprised eight EVs-derived RNAs, including FBXO7, MORF4L1, DDX17, TALDO1, AHNAK, TUBA1B, CD44, and SETD3. This model could well differentiate PDAC patients with a minimal AUC of 0.86 in internal verification using testing group. External validation using RT-qPCR data also exhibited a good classifier ability with an AUC of 0.89 when distinguishing PDAC from healthy controls. Conclusion: We've developed a qPCR-based, normalizer-free circulating EVs RNA classifier, which could well distinguish PDAC patients from noncancerous controls.

Biological insight into the extracellular vesicles in women with and without gestational diabetes

PURPOSE

Gestational diabetes mellitus (GDM) is the most common metabolic disorder in pregnancy, with increasing prevalence worldwide and still unclear pathogenic mechanisms. Extracellular vesicles (EVs) are emerging as potential biomarkers of disease-specific pathways in metabolic disorders, but their potential role in GDM is not fully understood. Therefore, the main aim of this study was to evaluate the link between EVs and hyperglycaemia during pregnancy.

METHODS

We assessed 50 GDM women and 50 controls at the third trimester of pregnancy in whom we collected demographic characteristics and clinical and anthropometric parameters. In addition, the circulating total EVs (tEVs) and their subpopulations were assessed using flow cytometry.

RESULTS

The levels of tEVs and EVs subtypes, expressed as median and interquartile range, were not significantly different between two groups; however, adipocyte-derived EVs (aEVs) concentration, expressed as percentage, was higher in controls than in GDM women (p = 0.045). In addition, a significant correlation was observed between aEVs (%) and third trimester total cholesterol (p = 0.022) within the GDM group. Furthermore, a significant correlation between endothelial-derived EVs (eEVs) and platelet-derived EVs (pEVs) within both groups was found, as well as a significant relation between aEVs and pEVs.

CONCLUSIONS

These data, although preliminary, represent the starting point for further studies to determine the role of circulating EVs in GDM.

MicroRNAs in the Spinal Microglia Serve Critical Roles in Neuropathic Pain

Neuropathic pain (NP) can occur after peripheral nerve injury (PNI), and it can be converted into a maladaptive, detrimental phenotype that causes a long-term state of pain hypersensitivity. In the last decade, the discovery that dysfunctional microglia evoke pain, called "microgliopathic pain," has challenged traditional neuronal views of "pain" and has been extensively explored. Recent studies have shown that microRNAs (miRNAs) can act as activators or inhibitors of spinal microglia in NP conditions. We first briefly review spinal microglial activation in NP. We then comprehensively describe miRNA expression changes and their potential mechanisms in the response of microglia to nerve injury. We summarize the roles of the following two representative miRNAs: miR-124, which reverses NP by keeping microglia quiescent, and miR-155, which promotes NP following microglial activation. Finally, we focused on the therapeutic potential of microglial miRNAs in NP. The findings we summarized may be essential tools for basic research and clinical treatment of NP.

Extracellular Vesicles in Fungi: Past, Present, and Future Perspectives

Extracellular vesicles (EVs) have garnered much interest in the cell biology and biomedical research fields. Many studies have reported the existence of EVs in all types of living cells, including in fifteen different fungal genera. EVs play diverse biological roles, from the regulation of physiological events and response to specific environmental conditions to the mediation of highly complex interkingdom communications. This review will provide a historical perspective on EVs produced by fungi and an overview of the recent discoveries in the field. We will also review the current knowledge about EV biogenesis and cargo, their role in cell-to-cell interactions, and methods of EV analysis. Finally, we will discuss the perspectives of EVs as vehicles for the delivery of biologically active molecules.

Serum piRNA-54265 is a New Biomarker for early detection and clinical surveillance of Human Colorectal Cancer

Background: Our previous study has demonstrated an oncogenic role of PIWI-interacting RNA-54265 (piR-54265) in colorectal cancer (CRC). Here, we investigate whether it can be a blood biomarker for population screening and clinical applications.

Methods: Serum piR-54265 levels were determined by a digital PCR method in 209 cancer-free healthy controls, 725 patients with CRC, 1303 patients with other types of digestive cancer and 192 patients with benign colorectal tumors. A prospective case-control analysis was conducted to assess the predictive value of serum piR-54265 for future CRC diagnosis. Receiver operating characteristic (ROC) curve was constructed to quantify the diagnostic performance of serum piR-54265 levels by assessing its sensitivity, specificity and respective areas under curve (AUC). The odds ratios (ORs) were computed using multivariate logistic regression models.

Results: Serum piR-54265 levels were significantly elevated only in patients with CRC compared with controls and patients with other cancer types. The AUC for recognizing CRC was 0.896 (95% CI, 0.874-0.914), with a sensitivity and specificity being 85.7% and 65.1% at 1500 copies/µL as a cut-off value. The serum piR-54265 levels in patients declined substantially after surgery but increased significantly again when tumor relapses. The prediagnostic serum piR-54265 levels were significantly associated with future CRC diagnosis, with the ORs of 7.23, 2.80, 2.45, and 1.24 for those whose CRC was diagnosed within 1, 2, 3 and >3 years. Serum piR-54265 test is more sensitive than other blood CRC markers.

Conclusion: Serum piR-54265 may serve as a valuable biomarker for CRC screening, early detection and clinical surveillance.

RNA delivery by extracellular vesicles in mammalian cells and its applications

The term 'extracellular vesicles' refers to a heterogeneous population of vesicular bodies of cellular origin that derive either from the endosomal compartment (exosomes) or as a result of shedding from the plasma membrane (microvesicles, oncosomes and apoptotic bodies). Extracellular vesicles carry a variety of cargo, including RNAs, proteins, lipids and DNA, which can be taken up by other cells, both in the direct vicinity of the source cell and at distant sites in the body via biofluids, and elicit a variety of phenotypic responses. Owing to their unique biology and roles in cell-cell communication, extracellular vesicles have attracted strong interest, which is further enhanced by their potential clinical utility. Because extracellular vesicles derive their cargo from the contents of the cells that produce them, they are attractive sources of biomarkers for a variety of diseases. Furthermore, studies demonstrating phenotypic effects of specific extracellular vesicle-associated cargo on target cells have stoked interest in extracellular vesicles as therapeutic vehicles. There is particularly strong evidence that the RNA cargo of extracellular vesicles can alter recipient cell gene expression and function. During the past decade, extracellular vesicles and their RNA cargo have become better defined, but many aspects of extracellular vesicle biology remain to be elucidated. These include selective cargo loading resulting in substantial differences between the composition of extracellular vesicles and source cells; heterogeneity in extracellular vesicle size and composition; and undefined mechanisms for the uptake of extracellular vesicles into recipient cells and the fates of their cargo. Further progress in unravelling the basic mechanisms of extracellular vesicle biogenesis, transport, and cargo delivery and function is needed for successful clinical implementation. This Review focuses on the current state of knowledge pertaining to packaging, transport and function of RNAs in extracellular vesicles and outlines the progress made thus far towards their clinical applications.

5-FU-Induced Upregulation of Exosomal PD-L1 Causes Immunosuppression in Advanced Gastric Cancer Patients

Although the cytotoxic chemotherapeutic agent 5-fluorouracil (5-FU) is generally considered to directly kill cancer cells and exert immunostimulatory effects in advanced gastric cancer, accumulating evidence indicates that it upregulates the expression of PD-L1, a representative immune checkpoint blockade molecule involved in negative regulation of the immune response. It was reported that exosomes could transfer functional PD-L1 locally and distantly to suppress the antitumor immune response. However, whether 5-FU alters the expression of exosomal PD-L1 and induces immunosuppression in gastric cancer remains unclear. Herein, we found that 5-FU increased gastric cancer-derived exosomal PD-L1. Importantly, compared with baseline levels, circulating exosomal PD-L1 was significantly upregulated in 21 stage III–IV gastric cancer patients after two, four, and six repeated cycles of fluoropyrimidine treatment (P = 0.009, P = 0.047, and P = 0.023, respectively), accompanied by decreased amounts of IFN-γ, TNF-α, IL-2, IL-6, and GM-CSF (P = 0.014, P = 0.004, P = 0.009, P = 0.031, and P = 0.014, respectively). Additionally, circulating exosomal PD-L1 was increased more significantly in clinical non-responders compared with responders (P = 0.018). Furthermore, exosomal PD-L1 induced apoptosis in Jurkat T cells and inhibited T cell activation in PBMCs, which could be partly reversed by nivolumab. These results suggested that 5-FU-induced upregulation of exosomal PD-L1 causes systemic immunosuppression in advanced gastric cancer following multiple cycles of chemotherapy, especially after two cycles.

The Course of Circulating Small Extracellular Vesicles in Patients Undergoing Surgical Aortic Valve Replacement

In the last years, increasing efforts have been devoted to investigating the role of small extracellular vesicles (sEVs) in cardiovascular diseases. These nano-sized particles (30-150 nm), secreted by different cell types, contain signalling molecules that enable participation in intercellular communication processes. In this study, we examined the course of circulating sEVs in patients undergoing surgical aortic valve replacement (SAVR) and correlated them with echocardiographic and standard blood parameters. Peripheral blood samples were collected from 135 patients undergoing SAVR preoperatively and at three follow-up points. Circulating sEVs were precipitated using Exoquick™ exosome isolation reagent and analyzed by nanoparticle tracking analysis (NTA). Our findings indicate that no more than 7 days after SAVR, there was a marked increase of circulating sEVs before returning to initial values after 3 months. Further, shear stress is not a trigger for the formation and release of circulating sEVs. Moreover, we pointed out a correlation between circulating sEVs and erythrocytes as well as LDH and creatinine levels in peripheral blood. Finally, all patients with a moderate prosthesis-patient mismatch as well as with an impaired left ventricular mass regression had lower levels of circulating sEVs 3 months after SAVR compared to their respective status before surgery. We conclude that in patients with aortic valve stenosis (AVS), sEVs may play an important part in mediating cell-cell communication and SAVR may have a crucial and lasting impact on their circulating levels. Besides, lower levels of sEVs portend to be associated with inferior recovery after major surgical interventions. The additional use of circulating sEVs beyond echocardiographic and laboratory parameters could have a prognostic value to estimate adverse outcomes in patients undergoing SAVR.

The mechanisms and treatments for sarcopenia: could exosomes be a perspective research strategy in the future?

The age-related loss of muscle mass and muscle function known as sarcopenia is a primary contributor to the problems faced by the old people. Sarcopenia has been a major public health problem with high prevalence in many countries. The related underlying molecular mechanisms of sarcopenia are not completely understood. This review is focused on the potential mechanisms and current research strategies for sarcopenia with the aim of facilitating the recognition and treatment of age-related sarcopenia. Previous studies suggested that protein synthesis and degradation, autophagy, impaired satellite cell activation, mitochondria dysfunction, and other factors associated with muscle weakness and muscle degeneration may be potential molecular pathophysiology of sarcopenia. Importantly, we also prospectively highlight that exosomes (small vesicles) as carriers can regulate muscle regeneration and protein synthesis according to recent researches. Dietary strategies and exercise represent the interventions that can also alleviate the progression of sarcopenia. At last, building on recent studies pointing to exosomes with the roles in increasing muscle regeneration, mediating the beneficial effects of exercise, and serving as messengers of intercellular communication and as carriers for research strategies of many diseases, we propose that exosomes could be a potential research direction or strategies of sarcopenia in the future.

Recent advances in understanding mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) are among of the most studied cell type for cellular therapy thanks to the ease of isolation, cultivation, and the high ex vivo expansion potential. In 2018, the European Medicines Agency finally granted the first marketing authorization for an MSC product. Despite the numerous promising results in preclinical studies, translation into routine practice still lags behind: therapeutic benefits of MSCs are not as satisfactory in clinical trial settings as they appear to be in preclinical models. The bench-to-bedside-and-back approach and careful evaluation of discrepancies between preclinical and clinical results have provided valuable insights into critical components of MSC manufacturing, their mechanisms of action, and how to evaluate and quality-control them. We sum up these past developments in the introductory section (“Mesenchymal stromal cells: name follows function”). From the huge amount of information, we then selected a few examples to illustrate challenges and opportunities to improve MSCs for clinical purposes. These include tissue origin of MSCs, MSC culture conditions, immune compatibility, and route of application and dosing. Finally, we add some information on MSC mechanisms of action and translation into potency assays and give an outlook on future perspectives raising the question of whether the future clinical product may be cell-based or cell-derived.

Functional and transcriptomic analysis of extracellular vesicles identifies calprotectin as a new prognostic marker in peripheral arterial disease (PAD)

Peripheral arterial disease (PAD) is associated with a high risk of cardiovascular events and death and is postulated to be a critical socioeconomic cost in the future. Extracellular vesicles (EVs) have emerged as potential candidates for new biomarker discovery related to their protein and nucleic acid cargo. In search of new prognostic and therapeutic targets in PAD, we determined the prothrombotic activity, the cellular origin and the transcriptomic profile of circulating EVs. This prospective study included control and PAD patients. Coagulation time (Procoag-PPL kit), EVs cellular origin and phosphatidylserine exposure were determined by flow cytometry in platelet-free plasma (n = 45 PAD). Transcriptomic profiles of medium/large EVs were generated using the MARS-Seq RNA-Seq protocol (n = 12/group). The serum concentration of the differentially expressed gene S100A9, in serum calprotectin (S100A8/A9), was validated by ELISA in control (n = 100) and PAD patients (n = 317). S100A9 was also determined in EVs and tissues of human atherosclerotic plaques (n = 3). Circulating EVs of PAD patients were mainly of platelet origin, predominantly Annexin V positive and were associated with the procoagulant activity of platelet-free plasma. Transcriptomic analysis of EVs identified 15 differentially expressed genes. Among them, serum calprotectin was elevated in PAD patients (p < 0.05) and associated with increased amputation risk before and after covariate adjustment (mean follow-up 3.6 years, p < 0.01). The combination of calprotectin with hs-CRP in the multivariate analysis further improved risk stratification (p < 0.01). Furthermore, S100A9 was also expressed in femoral plaque derived EVs and tissues. In summary, we found that PAD patients release EVs, mainly of platelet origin, highly positive for AnnexinV and rich in transcripts related to platelet biology and immune responses. Amputation risk prediction improved with calprotectin and was significantly higher when combined with hs-CRP. Our results suggest that EVs can be a promising component of liquid biopsy to identify the molecular signature of PAD patients.

The Level of Circulating Microparticles in Patients with Coronary Heart Disease: a Systematic Review and Meta-Analysis

BACKGROUND/AIMS

To assess the correlation between microparticles (MPs) and subgroups of coronary heart disease (CHD), including stable angina (SA), unstable angina (UA), and myocardial infarction (MI).

METHODS

A literature search was carried out systematically to identify available case-control studies. The level of MPs was compared and MPs' merged standardized mean differences (SMDs) were pooled for the meta-analysis.

RESULTS

Six studies met the inclusion criteria and were used for systematic review and meta-analysis. The level of MPs was higher in patients with CHD than that in the NS (normal subjects) group (SMD 2.28; 95% confidence interval (CI) 1.70-2.85; P = 0.000), and was also significantly different in subgroups of CHD (UA vs SA: SMD 2.35, 95% CI 1.56-3.14, P = 0.000; MI vs SA: SMD 3.08, 95% CI 2.07-4.09, P = 0.000; MI vs UA: SMD 0.83, 95% CI 0.41-1.26, P = 0.000). The similar results were also found in subgroups analyses of CD31⁺CD42^- endothelium-derived microparticles (EMPs) and CD144⁺EMPs.

CONCLUSION

The level of MPs, especially CD31⁺CD42^-EMPs and CD144⁺EMPs, had an increasing trend with the degree of CHD: NS<SA<UA<MI, suggesting that MPs might be a potential biomarker to identify SA, UA, and MI.

Increased Plasmatic Levels of PSA-Expressing Exosomes Distinguish Prostate Cancer Patients from Benign Prostatic Hyperplasia: A Prospective Study

Prostate Specific Antigen (PSA) fails to discriminate between benign prostatic hyperplasia (BPH) and Prostate Cancer (PCa), resulting in large numbers of unnecessary biopsies and missed cancer diagnoses. Nanovesicles called exosomes are directly detectable in patient plasma and here we explore the potential use of plasmatic exosomes expressing PSA (Exo-PSA) in distinguishing healthy individuals, BPH, and PCa. Exosomes were obtained from plasma samples of 80 PCa, 80 BPH, and 80 healthy donors (CTR). Nanoparticle Tracking Analysis (NTA), immunocapture-based ELISA (IC-ELISA), and nanoscale flow-cytometry (NSFC), were exploited to detect and characterize plasmatic exosomes. Statistical analysis showed that plasmatic exosomes expressing both CD81 and PSA were significantly higher in PCa as compared to both BPH and CTR, reaching 100% specificity and sensitivity in distinguishing PCa patients from healthy individuals. IC-ELISA, NSFC, and Exo-PSA consensus score (EXOMIX) showed 98% to 100% specificity and sensitivity for BPH-PCa discrimination. This study outperforms the conventional PSA test with a minimally invasive widely exploitable approach.

HIV-1-infected cell-derived exosomes promote the growth and progression of cervical cancer

Background: Women infected with HIV are more likely to have aggressive cervical cancer, and patients with HIV infection are often more severely ill than those without HIV infection. However, the underlying mechanism for the progression of cervical cancer is not yet fully understood and requires further research.

Methods: Exosomes were isolated from cell culture supernatants using differential ultracentrifugation. Confirmation of exosome isolation was based upon identification by electron microscopy and NanoSight particle tracking analysis of the purified fraction. The function of exosomes derived from HIV-infected T-cells in cervical cancer was determined by CCK8 and Transwell invasion assays.

Results: Exosomal miR-155-5p derived from HIV-infected T-cells promotes the proliferation, migration and invasion of cervical cancer cells. Furthermore, we found that HIV-infected T-cells secrete exosomal miR-155-5p that directly targets ARID2 degradation, leading to activation of the NF-κB signaling pathway. MiR-155-5p promotes cervical cancer progression by secreting proinflammatory cytokines, including IL-6 and IL-8.

Conclusions: In conclusion, we demonstrate that intercellular crosstalk between HIV-infected T-cells and cervical cancer is mediated by exosomes from HIV-infected T-cells that contribute to the malignant progression of cervical cancer, providing potential targets for the prevention and treatment of HIV-associated cervical cancer.

Micro-RNAs Are Related to Epicardial Adipose Tissue in Participants With Atrial Fibrillation: Data From the MiRhythm Study

Introduction: Epicardial adipose tissue (EAT) has been linked to incidence and recurrence of atrial fibrillation (AF), but the underlying mechanisms that mediate this association remain unclear. Circulating microRNAs (miRNAs) contribute to the regulation of gene expression in cardiovascular diseases, including AF. Thus, we sought to test the hypothesis that circulating miRNAs relate to burden of EAT.

Methods: We examined the plasma miRNA profiles of 91 participants from the miRhythm study, an ongoing study examining associations between miRNA and AF. We quantified plasma expression of 86 unique miRNAs commonly expressed in cardiomyocytes using quantitative reverse transcriptase polymerase chain reaction (qPCR). From computed tomography, we used validated methods to quantify the EAT area surrounding the left atrium (LA) and indexed it to body surface area (BSA) to calculate indexed LA EAT (iLAEAT). Participants were divided into tertiles of iLAEAT to identify associations with unique miRNAs. We performed logistic regression analyses adjusting for factors associated with AF to examine relations between iLAEAT and miRNA. We performed further bioinformatics analysis of miRNA predicted target genes to identify potential molecular pathways are regulated by the miRNAs.

Results: The mean age of the participants was 59 ± 9, 35% were women, and 97% were Caucasian. Participants in the highest tertile of iLAEAT were more likely to have hypertension, heart failure, and thick posterior walls. In regression analyses, we found that miRNAs 155-5p (p < 0.001) and 302a-3p (p < 0.001) were significantly associated with iLAEAT in patients with AF. The predicted targets of the miRNAs identified were implicated in the regulation of cardiac hypertrophy, adipogenesis, interleukin-8 (IL-8), and nerve growth factor (NGF) signaling.

Conclusion: miRNA as well as EAT have previously been linked to AF. Our finding that iLAEAT and miRNAs 155-5p and 302a-3p are associated suggest a possible direct link to between these entities in the development and maintenance of AF. Further research is needed to study causal relationships between these biomarkers.

Differences in the cargos and functions of exosomes derived from six cardiac cell types: a systematic review

Exosomes are bilayer membrane vesicles with cargos that contain a variety of surface proteins, markers, lipids, nucleic acids, and noncoding RNAs. Exosomes from different cardiac cells participate in the processes of cell migration, proliferation, apoptosis, hypertrophy, and regeneration, as well as angiogenesis and enhanced cardiac function, which accelerate cardiac repair. In this article, we mainly focused on the exosomes from six main types of cardiac cells, i.e., fibroblasts, cardiomyocytes, endothelial cells, cardiac progenitor cells, adipocytes, and cardiac telocytes. This may be the first article to describe the commonalities and differences in regard to the function and underlying mechanisms of exosomes among six cardiac cell types in cardiovascular disease.

Exosome-enriched fractions from MS B cells induce oligodendrocyte death

Objective

To identify whether factors toxic to oligodendrocytes (OLs), released by B cells from patients with MS, are found in extracellular microvesicles enriched in exosomes.

Methods

Conditioned medium (Sup) was obtained from cultures of blood B cells of patients with MS and normal controls (NCs). Exosome-enriched (Ex-En) fractions were prepared by solvent precipitation from Sup containing bovine serum and from serum-free Sup by ultracentrifugation (UC) or immunoprecipitation (IP) with antibodies to CD9. Ex-En fractions were diluted 1:4 with OL culture medium and screened for toxic effects on cultured rat OLs as measured by trypan blue uptake. Proteomic analysis was performed on Sup fractions.

Results

MS B cell–derived Ex-En fractions prepared from Sup by solvent extraction, UC, or IP induced OL death, whereas corresponding Ex-En fractions from NC showed little toxicity. Proteomic analysis of Sup demonstrated enrichment of proteins characteristic of exosomes from both NC and MS B-cell Sup. Ontology enrichment analysis suggested differences in the types and cargo of exosomes from MS Sup compared with NC, with proteins related to cell surface, extracellular plasma membrane, and gliogenesis enriched in MS.

Conclusions

Much of the in vitro toxicity of Sup from B cells of patients with relapsing-remitting MS is found in Ex-En fractions, as confirmed by 3 methods. Proteomic analysis of B-cell Sup indicates multiple differences between MS and NC.

Emerging roles and therapeutic value of exosomes in cancer metastasis

Exosomes are cell-derived vesicles of 30 to 150 nm that contain diverse proteins, nucleic acids, and lipids. These vesicles facilitate effective intercellular communication and trigger profound environmental changes. In recent years, many studies have identified diverse roles for exosomes in tumor metastasis, a major cause of cancer-related deaths; furthermore, circulating tumor-derived exosomes can drive the initiation and progression of metastasis and determine the specific target organs affected. Fortunately, our growing understanding of exosomes and relevant modification technology have provided new ideas for potential treatment of tumor metastases. Here we review recent advances concerning the role of exosomes in metastasis, focusing on their regulatory mechanisms and therapeutic targeting in advanced cancer.

The role of donor-derived exosomes in lung allograft rejection

Lung transplant recipients (LTxRs) with acute or chronic rejection release circulating exosomes that mostly originate from donor lung tissue and express mismatched human leucocyte antigens (HLA) and lung-associated self-antigens (SAgs), Collagen-V and K alpha 1 Tubulin. During lung transplant (LTx), donor lungs often undergo injuries that increase the antigenicity of the transplanted organ. 30% of LTxRs also have pre-transplant antibodies (Abs) to HLA and lung SAgs, which may induce conditions that increase the risk of chronic lung allograft dysfunction (CLAD). Post-transplant, some recipients experience de novo development of Abs to mismatched donor HLA (donor-specific antibody [DSA]) and Abs to lung SAgs, which have been implicated in CLAD pathogenesis. Because most LTxRs who develop DSA also develop Abs to SAgs, some have suggested a synergistic relationship between alloimmunity and autoimmunity in CLAD immunopathogenesis. These processes likely occur from stress-induced exosome release. Exosomes carry allo-antigens, lung SAgs, several micro RNAs, proteasome, co-stimulatory molecules, and pro-inflammatory transcription factors-resulting in efficient antigen presentation by direct, semidirect, and indirect pathways, leading to immune responses to both allo-antigens and lung-associated SAgs. This review summarizes recent findings on the role of exosomes, and processes triggering immune responses to allo-antigens and lung SAgs that ultimately culminate in CLAD.

An update on extracellular vesicles in multiple myeloma: a focus on their role in cell-to-cell cross-talk and as potential liquid biopsy biomarkers

INTRODUCTION

Multiple myeloma (MM) is characterized by a clonal proliferation of neoplastic plasma cells (PCs) in bone marrow (BM) and the interplay between MM PCs and the BM microenvironment, which plays a relevant role in its pathogenesis. In this important cross-talk, extracellular vesicles (EVs) are active. EVs, including small and medium/large EVs, are lipid bi-layer particles released in circulation by normal and neoplastic cells. A selected cargo of lipids, proteins, and nucleic acids is loaded into EVs, and delivered locally and to distant sites, thus influencing the physiology of recipient cells. In the 'liquid biopsy' context, EVs can be isolated from human biofluids proving to be powerful markers in cancer. Areas covered: Here, we summarize the recent advances on EVs in MM field. Expert commentary: EVs from MM PCs: i) enhance malignant cell proliferation and aggressiveness through an autocrine loop; ii) are able to transfer drug resistance in sensitive-drug cells; iii) stimulate angiogenesis; iv) increase the activity of osteoclasts; v) have immunosuppressive effects. In addition, EVs from MM stromal cells also promote MM cell proliferation and drug resistance. Finally, we underline the importance of EVs as MM potential biomarkers in 'cancer liquid biopsy' and as a potential new therapeutic target.