Circulating Extracellular Vesicles in Human Disease

Role of Extracellular Vesicles in the Pathogenesis of Vascular Damage

Extracellular vesicles (EVs) are nanosized membrane-bound structures released by cells that are able to transfer nucleic acids, protein cargos, and metabolites to specific recipient cells, allowing cell-to-cell communications in an endocrine and paracrine manner. Endothelial, leukocyte, and platelet-derived EVs have emerged both as biomarkers and key effectors in the development and progression of different stages of vascular damage, from earliest alteration of endothelial function, to advanced atherosclerotic lesions and cardiovascular calcification. Under pathological conditions, circulating EVs promote endothelial dysfunction by impairing vasorelaxation and instigate vascular inflammation by increasing levels of adhesion molecules, reactive oxygen species, and proinflammatory cytokines. Platelets, endothelial cells, macrophages, and foam cells secrete EVs that regulate macrophage polarization and contribute to atherosclerotic plaque progression. Finally, under pathological stimuli, smooth muscle cells and macrophages secrete EVs that aggregate between collagen fibers and serve as nucleation sites for ectopic mineralization in the vessel wall, leading to formation of micro- and macrocalcification. In this review, we summarize the emerging evidence of the pathological role of EVs in vascular damage, highlighting the major findings from the most recent studies and discussing future perspectives in this research field.

Engineered extracellular vesicles encapsulated Bryostatin-1 as therapy for neuroinflammation

Targeted and effective drug delivery to central nervous system (CNS) lesions is a major challenge in the treatment of multiple sclerosis (MS). Extracellular vesicles (EVs) have great promise as a drug delivery nanosystem given their unique characteristics, including a strong cargo-loading capacity, low immunogenicity, high biocompatibility, inherent stability, high delivery efficiency, ease of manipulation, and blood-brain barrier (BBB) penetration. Clinical applications are, however, limited by their insufficient targeting capability and "dilution effects" upon systemic administration. Neural stem cells (NSCs) provide an abundant source of EVs because of their remarkable capacity for self-renewal. Here, we developed a novel therapeutic strategy for local delivery and treatment using EVPs, which are derived from NSCs with the expression of the CNS lesion targeting ligand-PDGFRα. Furthermore, we used EVPs as a targeting carrier for encapsulating Bryostatin-1 (Bryo-1), a natural compound with remarkable anti-inflammation ability. Our data showed that Bryo-1 delivered by EVPs was more stable and concentrated in the CNS than native Bryo-1. Systemic injection of a low dosage (1 × 10⁸ particles) of EVPs + Bryo-1, versus only EVPs or Bryo-1 administration, significantly ameliorated clinical disease development, decreased the infiltration of pro-inflammatory cells, blocked myelin loss and astrogliosis, protected BBB integrity, and altered microglia pro-inflammatory phenotype in the CNS of EAE mice. Taken as a whole, our study showed that engineered EVs have a CNS targeting capacity, and it provides potentially powerful therapeutic effects for the treatment of various neuroinflammatory diseases.

Extracellular Vesicles as Biomarkers of Acute Graft-vs.-Host Disease After Haploidentical Stem Cell Transplantation and Post-Transplant Cyclophosphamide

Even with high-dose post-transplant cyclophosphamide (PT-Cy) which was initially introduced for graft-versus-host disease (GvHD) prevention in the setting of HLA-haploidentical transplantation, both acute and chronic GvHDs remain a major clinical challenge. Despite improvements in the understanding of the pathogenesis of both acute and chronic GvHDs, reliable biomarkers that predict their onset have yet to be identified. We recently studied the potential correlation between extracellular vesicles (EVs) and the onset of acute (a)GvHD in transplant recipients from related and unrelated donors. In the present study, we further investigated the role of the expression profile of membrane proteins and their microRNA (miRNA) cargo (miRNA100, miRNA155, and miRNA194) in predicting the onset of aGvHD in haploidentical transplant recipients with PT-Cy. Thirty-two consecutive patients were included. We evaluated the expression profile of EVs, by flow cytometry, and their miRNA cargo, by real-time PCR, at baseline, prior, and at different time points following transplant. Using logistic regression and Cox proportional hazard models, a significant association between expression profiles of antigens such as CD146, CD31, CD140a, CD120a, CD26, CD144, and CD30 on EVs, and their miRNA cargo with the onset of aGvHD was observed. Moreover, we also investigated a potential correlation between EV expression profile and cargo with plasma biomarkers (e.g., ST2, sTNFR1, and REG3a) that had been associated with aGVHD previously. This analysis showed that the combination of CD146, sTNFR1, and miR100 or miR194 strongly correlated with the onset of aGvHD (AUROC >0.975). A large prospective multicenter study is currently in progress to validate our findings.

Selective Isolation of Liver-Derived Extracellular Vesicles Redefines Performance of miRNA Biomarkers for Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease. Definitive diagnosis of the progressive form, non-alcoholic steatohepatitis (NASH), requires liver biopsy, which is highly invasive and unsuited to early disease or tracking changes. Inadequate performance of current minimally invasive tools is a critical barrier to managing NAFLD burden. Altered circulating miRNA profiles show potential for minimally invasive tracking of NAFLD. The selective isolation of the circulating extracellular vesicle subset that originates from hepatocytes presents an important opportunity for improving the performance of miRNA biomarkers of liver disease. The expressions of miR-122, -192, and -128-3p were quantified in total cell-free RNA, global EVs, and liver-specific EVs from control, NAFL, and NASH subjects. In ASGR1+ EVs, each miR biomarker trended positively with disease severity and expression was significantly higher in NASH subjects compared with controls. The c-statistic defining the performance of ASGR1+ EV derived miRNAs was invariably >0.78. This trend was not observed in the alternative sources. This study demonstrates the capacity for liver-specific isolation to transform the performance of EV-derived miRNA biomarkers for NAFLD, robustly distinguishing patients with NAFL and NASH.

Isolation of Circulating Extracellular Vesicles by High-Performance Size-Exclusion Chromatography

Circulating extracellular vesicles (EVs) are gaining increased attention as carriers of proteins, nucleic acids, and lipids. Blood contains EVs from different cell sources that constitute an attractive target for biomarker studies. However, there is no consensus on the best approach to isolate EVs from blood. Non-EV proteins and lipoproteins in plasma/serum tend to contaminate isolated EVs and confound functional experiments. Here we describe a single-step, high-performance size-exclusion chromatography procedure for separation of EVs from most lipoproteins and non-EV proteins, and compare it to ultracentrifugation, still the most commonly used method for EV isolation.

Circulating microRNA miR-137 as a stable biomarker for methamphetamine abstinence

OBJECTIVE

Stimulant use instigates abstinence syndrome in humans. miRNAs are a critical component for the pathophysiology of stimulant abstinence. Here we sought to identify a miRNA marker of methamphetamine abstinence in the circulating extracellular vesicles (cEVs).

METHODS

miR-137 in the cEVs was quantified by qPCR in thirty-seven patients under methamphetamine abstinence and thirty-five age-matched healthy controls recruited from 2014 to 2016 from the general adult population in a hospital setting, Seoul, South Korea. Diagnostic power was evaluated by area under curve in the receiver-operating characteristics curve and other multiple statistical parameters.

RESULTS

Patients under methamphetamine abstinence exhibited a significant reduction in cEV miR-137. Overall, cEV miR-137 had high potential as a blood-based marker of methamphetamine abstinence. cEV miR-137 retained the diagnostic power irrespective of the duration of methamphetamine abstinence or methamphetamine use. Interestingly, cEV miR-137 interacted with age: Control participants displayed an aging-dependent reduction of cEV miR-137, while methamphetamine-abstinent patients showed an aging-dependent increase in cEV miR-137. Accordingly, cEV miR-137 had variable diagnostic power depending on age, in which cEV miR-137 more effectively discriminated methamphetamine abstinence in the younger population. Duration of methamphetamine use or abstinence, cigarette smoking status, depressive disorder, or antidepressant treatment did not interact with the methamphetamine abstinence-induced reduction of cEV miR-137.

CONCLUSION

Our data collectively demonstrated that miR-137 in the circulating extracellular vesicles held high potential as a stable and accurate diagnostic marker of methamphetamine abstinence syndrome.

Plasma-derived extracellular vesicles from myocardial infarction patients inhibits tumor necrosis factor-alpha induced cardiac cell death

RATIONALE

Extracellular vesicles (EVs) derived exogenously from pluripotent stem cells or endogenously from healthy human serum exert cardioprotective effects after injury. However role of endogenous EVs from myocardial infarction (MI) patients not well understood in this settings.

METHODS AND RESULTS

The EVs from plasma of MI patients with preserved or reduced left ventricular ejection fraction (LVEF) and healthy controls (HC) were purified and characterized by flow cytometry, mass spectrometry (MS) and transmission electron microscopy (TEM). HCM and human cardiac microvascular endothelial cells (hCMVECs), under individual culture or co-culture, were used to study functional effects of EVs upon TNFα stimulation. These effects of EVs on HCM and hCMVECs were observed using cell death assays, western blots and confocal microscopy. Higher concentrations of platelet-, leukocyte-, endothelial- and erythrocyte-derived EVs were found in MI patients, both with preserved and reduced LVEF, compared to HC, and MS data on MI EVs proteome displayed alteration in several proteins. MI EVs protected HCM and hCMVECs against staurosporine-induced apoptosis. Furthermore, MI EVs were observed to abrogate TNFα-triggered HCM and hCMVECs death under both individually cultured and co-cultured conditions. MI EVs failed to inhibit TNFα induced hCMVECs and HCM activation when cultured individually, however co-cultured hCMVECs with HCM supported MI EVs capacity to attenuate TNFα induced cells activation. MI CD41+ EVs but not HC EVs were found to be internalized by HCM directly or migrated through hCMVECs to HCM. MI EVs indirectly restores TNFα mediated drop in mitochondrial membrane potential.

CONCLUSIONS

Endogenous EVs from MI patients, regardless of severity of the MI exert cardioprotective potential upon TNFα-induced cell death. Patient-derived EVs needs to be further explored to elucidate their potential cardioprotective role during MI.

Circulating extracellular vesicles and rheumatoid arthritis: a proteomic analysis

Circulating extracellular vesicles (EVs) are membrane-bound nanoparticles secreted by most cells for intracellular communication and transportation of biomolecules. EVs carry proteins, lipids, nucleic acids, and receptors that are involved in human physiology and pathology. EV cargo is variable and highly related to the type and state of the cellular origin. Three subtypes of EVs have been identified: exosomes, microvesicles, and apoptotic bodies. Exosomes are the smallest and the most well-studied class of EVs that regulate different biological processes and participate in several diseases, such as cancers and autoimmune diseases. Proteomic analysis of exosomes succeeded in profiling numerous types of proteins involved in disease development and prognosis. In rheumatoid arthritis (RA), exosomes revealed a potential function in joint inflammation. These EVs possess a unique function, as they can transfer specific autoantigens and mediators between distant cells. Current proteomic data demonstrated that exosomes could provide beneficial effects against autoimmunity and exert an immunosuppressive action, particularly in RA. Based on these observations, effective therapeutic strategies have been developed for arthritis and other inflammatory disorders.

Tissue-derived extracellular vesicles in cancers and non-cancer diseases: Present and future

Extracellular vesicles (EVs) are lipid‐bilayer membrane structures secreted by most cell types. EVs act as messengers via the horizontal transfer of lipids, proteins, and nucleic acids, and influence various pathophysiological processes in both parent and recipient cells. Compared to EVs obtained from body fluids or cell culture supernatants, EVs isolated directly from tissues possess a number of advantages, including tissue specificity, accurate reflection of tissue microenvironment, etc., thus, attention should be paid to tissue‐derived EVs (Ti‐EVs). Ti‐EVs are present in the interstitium of tissues and play pivotal roles in intercellular communication. Moreover, Ti‐EVs provide an excellent snapshot of interactions among various cell types with a common histological background. Thus, Ti‐EVs may be used to gain insights into the development and progression of diseases. To date, extensive investigations have focused on the role of body fluid‐derived EVs or cell culture‐derived EVs; however, the number of studies on Ti‐EVs remains insufficient. Herein, we summarize the latest advances in Ti‐EVs for cancers and non‐cancer diseases. We propose the future application of Ti‐EVs in basic research and clinical practice. Workflows for Ti‐EV isolation and characterization between cancers and non‐cancer diseases are reviewed and compared. Moreover, we discuss current issues associated with Ti‐EVs and provide potential directions.

An Abnormal Host/Microbiomes Signature of Plasma-Derived Extracellular Vesicles Is Associated to Polycythemia Vera

Polycythemia Vera (PV) is a myeloproliferative neoplasm with increased risk of thrombosis and progression to myelofibrosis. Chronic inflammation is commonly observed in myeloproliferative neoplasms including PV. The inflammatory network includes the extracellular vesicles (EVs), which play a role in cell-cell communication. Recent evidence points to circulating microbial components/microbes as potential players in hemopoiesis regulation. To address the role of EVs in PV, here we investigated phenotype and microbial DNA cargo of circulating EVs through multidimensional analysis. Peripheral blood and feces were collected from PV patients (n=38) and healthy donors (n=30). Circulating megakaryocyte (MK)- and platelet (PLT)-derived EVs were analyzed by flow cytometry. After microbial DNA extraction from feces and isolated EVs, the 16S rDNA V3-V4 region was sequenced. We found that the proportion of circulating MK-derived EVs was significantly decreased in PV patients as compared with the healthy donors. By contrast, the proportion of the PLT-derived EVs was increased. Interestingly, PV was also associated with a microbial DNA signature of the isolated EVs with higher diversity and distinct microbial composition than the healthy counterparts. Of note, increased proportion of isolated lipopolysaccharide-associated EVs has been demonstrated in PV patients. Conversely, the gut microbiome profile failed to identify a distinct layout between PV patients and healthy donors. In conclusion, PV is associated with circulating EVs harbouring abnormal phenotype and dysbiosis signature with a potential role in the (inflammatory) pathogenesis of the disease.

Plasma-Derived Extracellular Vesicles Circular RNAs Serve as Biomarkers for Breast Cancer Diagnosis

Breast cancer is the second cause of cancer-associated death among women and seriously endangers women's health. Therefore, early identification of breast cancer would be beneficial to women's health. At present, circular RNA (circRNA) not only exists in the extracellular vesicles (EVs) in plasma, but also presents distinct patterns under different physiological and pathological conditions. Therefore, we assume that circRNA could be used for early diagnosis of breast cancer. Here, we developed classifiers for breast cancer diagnosis that relied on 259 samples, including 144 breast cancer patients and 115 controls. In the discovery stage, we compared the genome-wide long RNA profiles of EVs in patients with breast cancer (n=14) and benign breast (n=6). To further verify its potential in early diagnosis of breast cancer, we prospectively collected plasma samples from 259 individuals before treatment, including 144 breast cancer patients and 115 controls. Finally, we developed and verified the predictive classifies based on their circRNA expression profiles of plasma EVs by using multiple machine learning models. By comparing their circRNA profiles, we found 439 circRNAs with significantly different levels between cancer patients and controls. Considering the cost and practicability of the test, we selected 20 candidate circRNAs with elevated levels and detected their levels by quantitative real-time polymerase chain reaction. In the training cohort, we found that BC_ExoC, a nine-circRNA combined classifier with SVM model, achieved the largest AUC of 0.83 [95% CI 0.77-0.88]. In the validation cohort, the predictive efficacy of the classifier achieved 0.80 [0.71-0.89]. Our work reveals the application prospect of circRNAs in plasma EVs as non-invasive liquid biopsies in the diagnosis and management of breast cancer.

Circulating Microvesicle-Associated Inducible Nitric Oxide Synthase Is a Novel Therapeutic Target to Treat Sepsis: Current Status and Future Considerations

To determine whether mitigating the harmful effects of circulating microvesicle-associated inducible nitric oxide (MV-A iNOS) in vivo increases the survival of challenged mice in three different mouse models of sepsis, the ability of anti-MV-A iNOS monoclonal antibodies (mAbs) to rescue challenged mice was assessed using three different mouse models of sepsis. The vivarium of a research laboratory Balb/c mice were challenged with an LD₈₀ dose of either lipopolysaccharide (LPS/endotoxin), TNFα, or MV-A iNOS and then treated at various times after the challenge with saline as control or with an anti-MV-A iNOS mAb as a potential immunotherapeutic to treat sepsis. Each group of mice was checked daily for survivors, and Kaplan–Meier survival curves were constructed. Five different murine anti-MV-A iNOS mAbs from our panel of 24 murine anti-MV-A iNOS mAbs were found to rescue some of the challenged mice. All five murine mAbs were used to genetically engineer humanized anti-MV-A iNOS mAbs by inserting the murine complementarity-determining regions (CDRs) into a human IgG_1,kappa scaffold and expressing the humanized mAbs in CHO cells. Three humanized anti-MV-A iNOS mAbs were effective at rescuing mice from sepsis in three different animal models of sepsis. The effectiveness of the treatment was both time- and dose-dependent. Humanized anti-MV-A iNOS rHJ mAb could rescue up to 80% of the challenged animals if administered early and at a high dose. Our conclusions are that MV-A iNOS is a novel therapeutic target to treat sepsis; anti-MV-A iNOS mAbs can mitigate the harmful effects of MV-A iNOS; the neutralizing mAb’s efficacy is both time- and dose-dependent; and a specifically targeted immunotherapeutic for MV-A iNOS could potentially save tens of thousands of lives annually and could result in improved antibiotic stewardship.

Diagnostic Impact of Radiological Findings and Extracellular Vesicles: Are We Close to Radiovesicolomics?

Simple Summary

Over the years, diagnostic tests such as in radiology and flow cytometry have become more and more powerful in the constant struggle against different pathologies, some of which are life-threatening. The possibility of using these “weapons” in a conjugated manner could result in higher healing and prevention rates, and a decrease in late diagnosis diseases. Different correlations among pathologies, extracellular vesicles (EVs), and radiological findings were recently demonstrated by many authors. Together with the increasing importance of “omics” sciences, and artificial intelligence in this new century, the perspective of a new research field called “radiovesicolomics” could be the missing link, enabling a different approach to disease diagnosis and treatment.

Abstract

Currently, several pathologies have corresponding and specific diagnostic and therapeutic branches of interest focused on early and correct detection, as well as the best therapeutic approach. Radiology never ceases to develop newer technologies in order to give patients a clear, safe, early, and precise diagnosis; furthermore, in the last few years diagnostic imaging panoramas have been extended to the field of artificial intelligence (AI) and machine learning. On the other hand, clinical and laboratory tests, like flow cytometry and the techniques found in the “omics” sciences, aim to detect microscopic elements, like extracellular vesicles, with the highest specificity and sensibility for disease detection. If these scientific branches started to cooperate, playing a conjugated role in pathology diagnosis, what could be the results? Our review seeks to give a quick overview of recent state of the art research which investigates correlations between extracellular vesicles and the known radiological features useful for diagnosis.

Vasodilator Dysfunction in Human Obesity: Established and Emerging Mechanisms

ABSTRACT

Human obesity is associated with insulin resistance and often results in a number of metabolic abnormalities and cardiovascular complications. Over the past decades, substantial advances in the understanding of the cellular and molecular pathophysiological pathways underlying the obesity-related vascular dysfunction have facilitated better identification of several players participating in this abnormality. However, the complex interplay between the disparate mechanisms involved has not yet been fully elucidated. Moreover, in medical practice, the clinical syndromes stemming from obesity-related vascular dysfunction still carry a substantial burden of morbidity and mortality; thus, early identification and personalized clinical management seem of the essence. Here, we will initially describe the alterations of intravascular homeostatic mechanisms occurring in arteries of obese patients. Then, we will briefly enumerate those recognized causative factors of obesity-related vasodilator dysfunction, such as vascular insulin resistance, lipotoxicity, visceral adipose tissue expansion, and perivascular adipose tissue abnormalities; next, we will discuss in greater detail some emerging pathophysiological mechanisms, including skeletal muscle inflammation, signals from gut microbiome, and the role of extracellular vesicles and microRNAs. Finally, it will touch on some gaps in knowledge, as well as some current acquisitions for specific treatment regimens, such as glucagon-like peptide-1 enhancers and sodium-glucose transporter2 inhibitors, that could arrest or slow the progression of this abnormality full of unwanted consequences.

The impact of obesity on adipocyte-derived extracellular vesicles

Recently, the emerging roles of adipocyte-derived extracellular vesicles (EVs) linking obesity and its comorbidities have been recognized. In obese subjects, adipocytes are having hypertrophic growth and are under stressed. The dysfunction adipocytes dysregulate the assembly of the biological components in the EVs including exosomes. This article critically reviews the current findings on the impact of obesity on the exosomal cargo contents that induce the pathophysiological changes. Besides, this review also summarizes the understanding on how obesity affects the biogenesis of adipocyte-derived exosomes and the exosome secretion. Furthermore, the differences of the exosomal contents in different adipose depots, and the impact of obesity on the exosomes that are derived from the stromal vascular fraction such as the adipose tissue macrophages and adipocyte-derived stem cells will also be discussed. The current development and potential application of exosome-based therapy will be summarized. This review provides crucial information for the design of novel exosome-based therapy for the treatment of obesity and its comorbidities.

Promising diagnostic biomarkers of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis: From clinical proteomics to microbiome

Fatty liver has been present in the lives of patients and physicians for almost two centuries. Vast knowledge has been generated regarding its etiology and consequences, although a long path seeking novel and innovative diagnostic biomarkers for nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) is still envisioned. On the one hand, proteomics and lipidomics have emerged as potential noninvasive resources for NAFLD diagnosis. In contrast, metabolomics has been able to distinguish between NAFLD and NASH, even detecting degrees of fibrosis. On the other hand, genetic and epigenetic markers have been useful in monitoring disease progression, eventually functioning as target therapies. Other markers involved in immune dysregulation, oxidative stress, and inflammation are involved in the instauration and evolution of the disease. Finally, the fascinating gut microbiome is significantly involved in NAFLD and NASH. This review presents state-of-the-art biomarkers related to NAFLD and NASH and new promises that could eventually be positioned as diagnostic resources for this disease. As is evident, despite great advances in studying these biomarkers, there is still a long path before they translate into clinical benefits.

Impact of the Main Cardiovascular Risk Factors on Plasma Extracellular Vesicles and Their Influence on the Heart's Vulnerability to Ischemia-Reperfusion Injury

The majority of cardiovascular deaths are associated with acute coronary syndrome, especially ST-elevation myocardial infarction. Therapeutic reperfusion alone can contribute up to 40 percent of total infarct size following coronary artery occlusion, which is called ischemia-reperfusion injury (IRI). Its size depends on many factors, including the main risk factors of cardiovascular mortality, such as age, sex, systolic blood pressure, smoking, and total cholesterol level as well as obesity, diabetes, and physical effort. Extracellular vesicles (EVs) are membrane-coated particles released by every type of cell, which can carry content that affects the functioning of other tissues. Their role is essential in the communication between healthy and dysfunctional cells. In this article, data on the variability of the content of EVs in patients with the most prevalent cardiovascular risk factors is presented, and their influence on IRI is discussed.

Targeting central nervous system extracellular vesicles enhanced triiodothyronine remyelination effect on experimental autoimmune encephalomyelitis

The lack of targeted and high-efficiency drug delivery to the central nervous system (CNS) nidus is the main problem in the treatment of demyelinating disease. Extracellular vesicles (EVs) possess great promise as a drug delivery vector given their advanced features. However, clinical applications are limited because of their inadequate targeting ability and the “dilution effects” after systemic administration. Neural stem cells (NSCs) supply a plentiful source of EVs on account of their extraordinary capacity for self-renewal. Here, we have developed a novel therapeutic system using EVs from modified NSCs with high expressed ligand PDGF-A (EVPs) and achieve local delivery. It has been demonstrated that EVPs greatly enhance the target capability on oligodendrocyte lineage. Moreover, EVPs are used for embedding triiodothyronine (T3), a thyroid hormone that is critical for oligodendrocyte development but has serious side effects when systemically administered. Our results demonstrated that systemic injection of EVPs + T3, versus EVPs or T3 administration individually, markedly alleviated disease development, enhanced oligodendrocyte survival, inhibited myelin damage, and promoted myelin regeneration in the lesions of experimental autoimmune encephalomyelitis mice. Taken together, our findings showed that engineered EVPs possess a remarkable CNS lesion targeting potential that offers a potent therapeutic strategy for CNS demyelinating diseases as well as neuroinflammation.

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NSC-derived EV-PDGFA dramatically increased targeting efficiency to the lineage of OLGs and the demyelinated area in the CNS.

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EVPs-T3 exert the therapeutic ability in the lesion suppressed the disease development and protected myelin loss.

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EVPs-T3 increased numbers of OLGs in the lesion and TEM data evidenced that EVPs-T3 promotes myelin regeneration in vivo.

Extracellular vesicles: Potential impact on cardiovascular diseases

Extracellular vesicles (EVs) have received considerable attention in biological and clinical research due to their ability to mediate cell-to-cell communication. Based on their size and secretory origin, EVs are categorized as exosomes, microvesicles, and apoptotic bodies. Increasing number of studies highlight the contribution of EVs in the regulation of a wide range of normal cellular physiological processes, including waste scavenging, cellular stress reduction, intercellular communication, immune regulation, and cellular homeostasis modulation. Altered circulating EV level, expression pattern, or content in plasma of patients with cardiovascular disease (CVD) may serve as diagnostic and prognostic biomarkers in diverse cardiovascular pathologies. Due to their inherent characteristics and physiological functions, EVs, in turn, have become potential candidates as therapeutic agents. In this review, we discuss the evolving understanding of the role of EVs in CVD, summarize the current knowledge of EV-mediated regulatory mechanisms, and highlight potential strategies for the diagnosis and therapy of CVD. We also attempt to look into the future that may advance our understanding of the role of EVs in the pathogenesis of CVD and provide novel insights into the field of translational medicine.

Characterization of Marine Organism Extracellular Matrix-Anchored Extracellular Vesicles and Their Biological Effect on the Alleviation of Pro-Inflammatory Cytokines

Representative marine materials such as biopolymers and bioceramics contain bioactive properties and are applied in regenerative medicine and tissue engineering. The marine organism-derived extracellular matrix (ECM), which consists of structural and functional molecules, has been studied as a biomaterial. It has been used to reconstruct tissues and improve biological functions. However, research on marine-derived extracellular vesicles (EVs) among marine functional materials is limited. Recent studies on marine-derived EVs were limited to eco-system studies using bacteria-released EVs. We aimed to expand the range of representative marine organisms such as fish, crustaceans, and echinoderms; establish the extraction process; and study the bioactivity capability of marine EVs. Results confirmed that marine organism ECM-anchored EVs (mEVs) have a similar morphology and cargos to those of EVs in land animals. To investigate physiological effects, lipopolysaccharide (LPS)-infected macrophages were treated with EVs derived from sea cucumber, fish, and shrimp. A comparison of the expression levels of inflammatory cytokine genes revealed that all types of mEVs alleviated pro-inflammatory cytokines, although to different degrees. Among them, the sea cucumber-derived EVs showed the strongest suppression ability. This study showed that research on EVs derived from various types of marine animals can lead to the development of high value-added therapeutics from discarded marine wastes.

Macrophagic Extracellular Vesicle CXCL2 Recruits and Activates the Neutrophil CXCR2/PKC/NOX4 Axis in Sepsis

Sepsis is a life-threatening organ dysfunction caused by a dysfunctional host response to infection. Neutrophils play a protective role by releasing antibacterial proteins or by phagocytizing bacteria. However, excess neutrophils can induce tissue damage. Recently, a novel intercellular communication pathway involving extracellular vesicles (EVs) has garnered considerable attention. However, whether EVs secreted by macrophages mediate neutrophil recruitment to infected sites has yet to be studied. In this study, we assessed the chemotactic effect of EVs isolated from mouse Raw264.7 macrophages on mouse neutrophils and found that CXCL2 was highly expressed in these EVs. By regulating CXCL2 in Raw264.7 macrophages, we found that CXCL2 on macrophage EVs recruited neutrophils in vitro and in vivo. The CXCL2 EVs activated the CXCR2/PKC/NOX4 pathway and induced tissue damage. This study provides information regarding the mechanisms underlying neutrophil recruitment to tissues and proposes innovative strategies and targets for the treatment of sepsis.

MicroRNA in extracellular vesicles regulates inflammation through macrophages under hypoxia

Extracellular vesicle (EV), critical mediators of cell-cell communication, allow cells to exchange proteins, lipids, and genetic material and therefore profoundly affect the general homeostasis. A hypoxic environment can affect the biogenesis and secrete of EVs, and the cargoes carried can participate in a variety of physiological and pathological processes. In hypoxia-induced inflammation, microRNA(miRNA) in EV participates in transcriptional regulation through various pathways to promote or reduce the inflammatory response. Meanwhile, as an important factor of immune response, the polarization of macrophages is closely linked to miRNAs, which will eventually affect the inflammatory state. In this review, we outline the possible molecular mechanism of EV changes under hypoxia, focusing on the signaling pathways of several microRNAs involved in inflammation regulation and describing the process and mechanism of EV-miRNAs regulating macrophage polarization in hypoxic diseases.

A Specific Host/Microbial Signature of Plasma-Derived Extracellular Vesicles Is Associated to Thrombosis and Marrow Fibrosis in Polycythemia Vera

Simple Summary

Patients with polycythemia vera, a myeloproliferative neoplasm, are at increased risk of thrombosis and progression to myelofibrosis. However, no disease-specific risk factors have been identified so far. Extracellular vesicles, released from a broad variety of cells, are receiving increasing attention for their effects on cell-to-cell communication. In addition, they play a role in cancer and thrombosis. Interestingly, circulating microbial components/microbes have been recently indicated as potential modifiers of inflammation and coagulation. Here, we identified a signature of thrombosis history and marrow fibrosis by analyzing the phenotype and the microbial DNA cargo of the circulating extracellular vesicles after isolation from the plasma of patients with polycythemia vera. These data may support the role of extracellular vesicles as liquid biomarkers of aggressive disease, thus contributing to refining the prognosis of polycythemia vera.

Abstract

Polycythemia vera is a myeloproliferative neoplasm with increased risk of thrombosis and progression to myelofibrosis. However, no disease-specific risk factors have been identified so far. Circulating extracellular vesicles (EVs) are mostly of megakaryocyte (MK-EVs) and platelet (PLT-EVs) origin and, along with phosphatidylethanolamine (PE)-EVs, play a role in cancer and thrombosis. Interestingly, circulating microbial components/microbes have been recently indicated as potential modifiers of inflammation and coagulation. Here, we investigated phenotype and microbial DNA cargo of EVs after isolation from the plasma of 38 patients with polycythemia vera. Increased proportion of MK-EVs and reduced proportion of PLT-EVs identify patients with thrombosis history. Interestingly, EVs from patients with thrombosis history were depleted in Staphylococcus DNA but enriched in DNA from Actinobacteria members as well as Anaerococcus. In addition, patients with thrombosis history had also lower levels of lipopolysaccharide-associated EVs. In regard to fibrosis, along with increased proportion of PE-EVs, the EVs of patients with marrow fibrosis were enriched in DNA from Collinsella and Flavobacterium. Here, we identified a polycythemia-vera-specific host/microbial EV-based signature associated to thrombosis history and marrow fibrosis. These data may contribute to refining PV prognosis and to identifying novel druggable targets.

Friends and foes: Extracellular vesicles in aging and rejuvenation

Extracellular vesicles (EVs) are released by many different cell types throughout the body and play a role in a diverse range of biological processes. EVs circulating in blood as well as in other body fluids undergo dramatic alterations over an organism's lifespan that are only beginning to be elucidated. The exact nature of these changes is an area of active and intense investigation, but lacks clear consensus due to the substantial heterogeneity in EV subpopulations and insufficiencies in current technologies. Nonetheless, emerging evidence suggests that EVs regulate systemic aging as well as the pathophysiology of age-related diseases. Here, we review the current literature investigating EVs and aging with an emphasis on consequences for the maintenance of human healthspan. Intriguingly, the biological utility of EVs both in vitro and in vivo and across contexts depends on the states of the source cells or tissues. As such, EVs secreted by cells in an aged or pathological state may impose detrimental consequences on recipient cells, while EVs secreted by youthful or healthy cells may promote functional improvement. Thus, it is critical to understand both functions of EVs and tip the balance toward their beneficial effects as an antiaging intervention.

Erythrocyte flow through the interendothelial slits of the splenic venous sinus

The flow patterns of red blood cells through the spleen are intimately linked to clearance of senescent RBCs, with clearance principally occurring within the open flow through the red pulp and slits of the venous sinus system that exists in humans, rats, and dogs. Passage through interendothelial slits (IESs) of the sinus has been shown by MacDonald et al. (Microvasc Res 33:118-134, 1987) to be mediated by the caliber, i.e., slit opening width, of these slits. IES caliber within a given slit of a given sinus section has been shown to operate in an asynchronous manner. Here, we describe a model and simulation results that demonstrate how the supporting forces exerted on the sinus by the reticular meshwork of the red pulp, combined with asymmetrical contractility of stress fibers within the endothelial cells comprising the sinus, describe this vital and intriguing behavior. These results shed light on the function of the sinus slits in species such as humans, rats, and dogs that possess sinusoidal sinuses. Instead of assuming a passive mechanical filtering mechanism of the IESs, our proposed model provides a mechanically consistent explanation for the dynamically modulated IES opening/filtering mechanism observed in vivo. The overall perspective provided is also consistent with the view that IES passage serves as a self-protective mechanism in RBC vesiculation and inclusion removal.

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.

Extracellular Vesicles: Emerging Therapeutics in Cutaneous Lesions

Extracellular vesicles (EVs), as nanoscale membranous vesicles containing DNAs, RNAs, lipids and proteins, have emerged as promising diagnostic and therapeutic agents for skin diseases. Here, we summarize the basic physiology of the skin and the biological characteristic of EVs. Further, we describe the applications of EVs in the treatment of dermatological conditions such as skin infection, inflammatory skin diseases, skin repair and rejuvenation and skin cancer. In particular, plant-derived EVs and clinical trials are discussed. In addition, challenges and perspectives related to the preclinical and clinical applications of EVs are highlighted.

Serum-Derived Neuronal Exosomal miRNAs as Biomarkers of Acute Severe Stress

Stress is the physical and psychological tension felt by an individual while adapting to difficult situations. Stress is known to alter the expression of stress hormones and cause neuroinflammation in the brain. In this study, miRNAs in serum-derived neuronal exosomes (nEVs) were analyzed to determine whether differentially expressed miRNAs could be used as biomarkers of acute stress. Specifically, acute severe stress was induced in Sprague-Dawley rats via electric foot-shock treatment. In this acute severe-stress model, time-dependent changes in the expression levels of stress hormones and neuroinflammation-related markers were analyzed. In addition, nEVs were isolated from the serum of control mice and stressed mice at various time points to determine when brain damage was most prominent; this was found to be 7 days after foot shock. Next-generation sequencing was performed to compare neuronal exosomal miRNA at day 7 with the neuronal exosomal miRNA of the control group. From this analysis, 13 upregulated and 11 downregulated miRNAs were detected. These results show that specific miRNAs are differentially expressed in nEVs from an acute severe-stress animal model. Thus, this study provides novel insights into potential stress-related biomarkers.

Neutrophil-to-hepatocyte communication via LDLR-dependent miR-223-enriched extracellular vesicle transfer ameliorates nonalcoholic steatohepatitis

Neutrophil infiltration around lipotoxic hepatocytes is a hallmark of nonalcoholic steatohepatitis (NASH); however, how these 2 types of cells communicate remains obscure. We have previously demonstrated that neutrophil-specific microRNA-223 (miR-223) is elevated in hepatocytes to limit NASH progression in obese mice. Here, we demonstrated that this elevation of miR-223 in hepatocytes was due to preferential uptake of miR-223-enriched extracellular vesicles (EVs) derived from neutrophils as well other types of cells, albeit to a lesser extent. This selective uptake was dependent on the expression of low-density lipoprotein receptor (LDLR) on hepatocytes and apolipoprotein E (APOE) on neutrophil-derived EVs, which was enhanced by free fatty acids. Once internalized by hepatocytes, the EV-derived miR-223 acted to inhibit hepatic inflammatory and fibrogenic gene expression. In the absence of this LDLR- and APOE-dependent uptake of miR-223-enriched EVs, the progression of steatosis to NASH was accelerated. In contrast, augmentation of this transfer by treatment with an inhibitor of proprotein convertase subtilisin/kexin type 9, a drug used to lower blood cholesterol by upregulating LDLR, ameliorated NASH in mice. This specific role of LDLR and APOE in the selective control of miR-223-enriched EV transfer from neutrophils to hepatocytes may serve as a potential therapeutic target for NASH.

Association of Circulating, Inflammatory-Response Exosomal mRNAs With Acute Myocardial Infarction

Background: Although many cardiovascular disease studies have focused on the microRNAs of circulating exosomes, the profile and the potential clinical diagnostic value of plasma exosomal long RNAs (exoLRs) are unknown for acute myocardial infarction (AMI).

Methods: In this study, the exoLR profile of 10 AMI patients, eight stable coronary artery disease (CAD) patients, and 10 healthy individuals was assessed by RNA sequencing. Bioinformatic approaches were used to investigate the characteristics and potential clinical value of exoLRs.

Results: Exosomal mRNAs comprised the majority of total exoLRs. Immune cell types analyzed by CIBERSORT showed that neutrophils and monocytes were significantly enriched in AMI patients, consistent with clinical baseline values. Biological process enrichment analysis and co-expression network analysis demonstrated neutrophil activation processes to be enriched in AMI patients. Furthermore, two exosomal mRNAs, ALPL and CXCR2, were identified as AMI biomarkers that may be useful for evaluation of the acute inflammatory response mediated by neutrophils.

Conclusions: ExoLRs were assessed in AMI patients and found to be associated with the acute inflammatory response mediated by neutrophils. Exosomal mRNAs, ALPL and CXCR2, were identified as potentially useful biomarkers for the study of AMI.

The biological significance and clinical utility of emerging blood biomarkers for traumatic brain injury

HUIBREGTSE, M.E, Bazarian, J.J., Shultz, S.R., and Kawata K. The biological significance and clinical utility of emerging blood biomarkers for traumatic brain injury. NEUROSCI BIOBEHAV REV XX (130) 433-447, 2021.- Blood biomarkers can serve as objective measures to gauge traumatic brain injury (TBI) severity, identify patients at risk for adverse outcomes, and predict recovery duration, yet the clinical use of blood biomarkers for TBI is limited to a select few and only to rule out the need for CT scanning. The biomarkers often examined in neurotrauma research are proteomic markers, which can reflect a range of pathological processes such as cellular damage, astrogliosis, or neuroinflammation. However, proteomic blood biomarkers are vulnerable to degradation, resulting in short half-lives. Emerging biomarkers for TBI may reflect the complex genetic and neurometabolic alterations that occur following TBI that are not captured by proteomics, are less vulnerable to degradation, and are comprised of microRNA, extracellular vesicles, and neurometabolites. Therefore, this review aims to summarize our understanding of how biomarkers for brain injury escape the brain parenchymal space and appear in the bloodstream, update recent research findings in several proteomic biomarkers, and characterize biological significance and examine clinical utility of microRNA, extracellular vesicles, and neurometabolites.

Recent advances in dielectrophoresis toward biomarker detection: A summary of studies published between 2014 and 2021

Dielectrophoresis is a well-understood phenomenon that has been widely utilized in biomedical applications. Recent advancements in miniaturization have contributed to the development of dielectrophoretic-based devices for a wide variety of biomedical applications. In particular, the integration of dielectrophoresis with microfluidics, fluorescence, and electrical impedance has produced devices and techniques that are attractive for screening and diagnosing diseases. This review article summarizes the recent utility of dielectrophoresis in assays of biomarker detection. Common screening and diagnostic biomarkers, such as cellular, protein, and nucleic acid, are discussed. Finally, the potential use of recent developments in machine learning approaches toward improving biomarker detection performance is discussed. This review article will be useful for researchers interested in the recent utility of dielectrophoresis in the detection of biomarkers and for those developing new devices to address current gaps in dielectrophoretic biomarker detection.

Extracellular vesicles package dsDNA to aggravate Crohn's disease by activating the STING pathway

Crohn's disease (CD) is an intestinal immune-dysfunctional disease. Extracellular vesicles (EVs) are membrane-enclosed particles full of functional molecules, e.g., nuclear acids. Recently, EVs have been shown to participate in the development of CD by realizing intercellular communication among intestinal cells. However, the role of EVs carrying double-strand DNA (dsDNA) shed from sites of intestinal inflammation in CD has not been investigated. Here we isolated EVs from the plasma or colon lavage of murine colitis and CD patients. The level of exosomal dsDNA, including mtDNA and nDNA, significantly increased in murine colitis and active human CD, and was positively correlated with the disease activity. Moreover, the activation of the STING pathway was verified in CD. EVs from the plasma of active human CD triggered STING activation in macrophages in vitro. EVs from LPS-damaged colon epithelial cells were also shown to raise inflammation in macrophages via activating the STING pathway, but the effect disappeared after the removal of exosomal dsDNA. These findings were further confirmed in STING-deficient mice and macrophages. STING deficiency significantly ameliorated colitis. Besides, potential therapeutic effects of GW4869, an inhibitor of EVs release were assessed. The application of GW4869 successfully ameliorated murine colitis by inhibiting STING activation. In conclusion, exosomal dsDNA was found to promote intestinal inflammation via activating the STING pathway in macrophages and act as a potential mechanistic biomarker and therapeutic target of CD.

Overexpression of miR-223 Promotes Tolerogenic Properties of Dendritic Cells Involved in Heart Transplantation Tolerance by Targeting Irak1

Dendritic cells (DCs) are key mediators of transplant rejection. Numerous factors have been identified that regulate transplant immunopathology by modulating the function of DCs. Among these, microRNAs (miRNAs), small non-coding RNA molecules, have received much attention. The miRNA miR-223 is very highly expressed and tightly regulated in hematopoietic cells. It plays an important role in modulating the immune response by regulating neutrophils and macrophages, and its dysregulation contributes to multiple types of immune diseases. However, the role of miR-223 in immune rejection is unclear. Here, we observed expression of miR-223 in patients and mice who had undergone heart transplantation and found that it increased in the serum of both, and also in DCs from the spleens of recipient mice, although it was unchanged in splenic T cells. We also found that miR-223 expression decreased in lipopolysaccharide-stimulated DCs. Increasing the level of miR-223 in DCs promoted polarization of DCs toward a tolerogenic phenotype, which indicates that miR-223 can attenuate activation and maturation of DCs. MiR-223 effectively induced regulatory T cells (Tregs) by inhibiting the function of antigen-presenting DCs. In addition, we identified Irak1 as a miR-223 target gene and an essential regulator of DC maturation. In mouse allogeneic heterotopic heart transplantation models, grafts survived longer and suffered less immune cell infiltration in mice with miR-223-overexpressing immature (im)DCs. In the miR-223-overexpressing imDC recipients, T cells from spleen differentiated into Tregs, and the level of IL-10 in heart grafts was markedly higher than that in the control group. In conclusion, miR-223 regulates the function of DCs via Irak1, differentiation of T cells into Tregs, and secretion of IL-10, thereby suppressing allogeneic heart graft rejection.

Exosomes: Potential Disease Biomarkers and New Therapeutic Targets

Exosomes are extracellular vesicles released by cells, both constitutively and after cell activation, and are present in different types of biological fluid. Exosomes are involved in the pathogenesis of diseases, such as cancer, neurodegenerative diseases, pregnancy disorders and cardiovascular diseases, and have emerged as potential non-invasive biomarkers for the detection, prognosis and therapeutics of a myriad of diseases. In this review, we describe recent advances related to the regulatory mechanisms of exosome biogenesis, release and molecular composition, as well as their role in health and disease, and their potential use as disease biomarkers and therapeutic targets. In addition, the advantages and disadvantages of their main isolation methods, characterization and cargo analysis, as well as the experimental methods used for exosome-mediated drug delivery, are discussed. Finally, we present potential perspectives for the use of exosomes in future clinical practice.

Extracellular Vesicles in Acute Kidney Injury and Clinical Applications

Acute kidney injury (AKI)––the sudden loss of kidney function due to tissue damage and subsequent progression to chronic kidney disease––has high morbidity and mortality rates and is a serious worldwide clinical problem. Current AKI diagnosis, which relies on measuring serum creatinine levels and urine output, cannot sensitively and promptly report on the state of damage. To address the shortcomings of these traditional diagnosis tools, several molecular biomarkers have been developed to facilitate the identification and ensuing monitoring of AKI. Nanosized membrane-bound extracellular vesicles (EVs) in body fluids have emerged as excellent sources for discovering such biomarkers. Besides this diagnostic purpose, EVs are also being extensively exploited to deliver therapeutic macromolecules to damaged kidney cells to ameliorate AKI. Consequently, many successful AKI biomarker findings and therapeutic applications based on EVs have been made. Here, we review our understanding of how EVs can help with the early identification and accurate monitoring of AKI and be used therapeutically. We will further discuss where current EV-based AKI diagnosis and therapeutic applications fall short and where future innovations could lead us.

Exosomes: Structure, Biogenesis, Types and Application in Diagnosis and Gene and Drug Delivery

In recent times, several approaches for targeted gene therapy (GT) had been studied. However, the emergence of extracellular vesicles (EVs) as a shuttle carrying genetic information between cells has gained a lot of interest in scientific communities. Owing to their higher capabilities in dealing with short sequences of nucleic acid (mRNA, miRNA), proteins, recombinant proteins, exosomes, the most popular form of EVs are viewed as reliable biological therapeutic conveyers. They have natural access through every biological membrane and can be employed for site-specific and efficient drug delivery without eliciting any immune responses hence, qualifying as an ideal delivery vehicle. Also, there are many research studies conducted in the last few decades on using exosome-mediated gene therapy into developing an effective therapy with the concept of a higher degree of precision in gene isolation, purification and delivery mechanism loading, delivery and targeting protocols. This review discusses several facets that contribute towards developing an efficient therapeutic regime for gene therapy, highlighting limitations and drawbacks associated with current GT and suggested therapeutic regimes.

Increased concentrations of myeloperoxidase in serum and serum extracellular vesicles are associated with type 2 diabetes mellitus

BACKGROUND

Inflammatory response plays a critical role in the initiation and progression of type 2 diabetes mellitus (T2DM). Myeloperoxidase (MPO), a leukocyte-derived protagonist, exerts its proinflammatory properties in many complications. We explored the associations between serum extracellular vesicle (EV)-derived MPO as well as serum MPO and T2DM.

METHODS

We performed a cross-sectional study in 151 individuals, including 93 patients with T2DM and 58 non-T2DM controls. The concentrations of serum EV-derived MPO and serum MPO were measured by Luminex Assay.

RESULTS

Our data showed that serum EV-derived MPO concentrations and serum MPO concentrations were significantly higher in T2DM patients compared with non-T2DM subjects. In addition, multivariate logistic regression analysis revealed that serum EV-derived MPO as well as serum MPO was independently associated with the presence of T2DM even after adjusting for confounding factors (OR = 1.836 /1 ng EV-derived MPO, 95% CI = 1.395-2.417, P < 0.001; OR = 4.135 /10 ng serum MPO, 95% CI = 2.285-7.483, P < 0.001). Furthermore, serum MPO showed marginally higher discriminatory accuracy than serum EV-derived MPO in screening T2DM (AUC = 0.858; AUC = 0.779).

CONCLUSION

Increased concentrations of the inflammatory marker MPO either in serum or in serum EVs were independently associated with T2DM.

Role of extracellular vesicle derived biomarkers in drug metabolism and disposition

Extracellular vesicles (EVs) are small, non-replicating, lipid encapsulated particles that contain a myriad of protein and nucleic acid cargo derived from their tissue of origin. The potential role of EV derived biomarkers to the study of drug metabolism and disposition (DMD) has gained attention in recent years. The key trait that makes EVs an attractive biomarker source is their capacity to provide comparable insights to solid organ biopsy through an appreciably less invasive collection procedure. Blood-derived EVs exist as a heterogenous milieu of biologically distinct particles originating from different sources through different biogenesis pathways. Furthermore, blood (plasma and serum) contains an array of vesicular and non-vesicular contaminants such as apoptotic bodies, plasma proteins and lipoproteins that are routinely co-isolated with EVs albeit to a different extent depending on the isolation technique. The following mini-review summarises current studies reporting DMD biomarkers and addresses elements of EV isolation and quantification relevant to the application of EV derived DMD biomarkers. Evidence based best practice guidance aligned to Minimum Information for the Study of Extracellular Vesicles (MISEV) and EV Track reporting standards are summarised in the context of DMD studies. Significance Statement Extracellular vesicle (EV) derived protein and nucleic acid cargo represent a potentially game changing source of novel DMD biomarkers with the capacity to define within- and between- individual variability in drug exposure irrespective of aetiology. However, robust translation of EV-derived biomarkers requires the generation of transparent reproducible evidence. This review outlines the critical elements of data generation and reporting relevant to achieving this evidence in a drug metabolism and disposition context.

Emerging Nano-Carrier Strategies for Brain Tumor Drug Delivery and Considerations for Clinical Translation

Treatment of brain tumors is challenging since the blood–brain tumor barrier prevents chemotherapy drugs from reaching the tumor site in sufficient concentrations. Nanomedicines have great potential for therapy of brain disorders but are still uncommon in clinical use despite decades of research and development. Here, we provide an update on nano-carrier strategies for improving brain drug delivery for treatment of brain tumors, focusing on liposomes, extracellular vesicles and biomimetic strategies as the most clinically feasible strategies. Finally, we describe the obstacles in translation of these technologies including pre-clinical models, analytical methods and regulatory issues.

Platelet, Red Cell, and Endothelial Activation and Injury During Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) can be lifesaving but suffers from high rates of bleeding and repeated transfusions. Current monitoring of blood cell damage during ECMO is limited to platelet counts, hematocrit, and plasma hemoglobin levels. Extracelluar vesicles (EV) are small cell fragments released when cells are activated/injured. The objective was to evaluate flow cytometric measurements of EV during ECMO as an indication of platelet, red cell, and endothelial activation/injury. Samples were collected from 55 patients (1 day to 19 years) during 58 ECMO runs. ECMO activated or injured blood cells, but the extent was highly variable and patient dependent. On average platelet activation was increased sevenfold during ECMO with up to 60-fold increased activation during the first 24 hours in some patients. EV associated with platelet and red-cell injury were increased eightfold on average but up to 200-fold in patients with disseminated intravascular coagulation, severe hemolysis, or massive transfusion. Approximately 9% of ECMO patients showed a red-cell and endothelial activation pattern that was associated with poor prognosis. Extracellular vesicles with autofluorescence similar to bilirubin appeared to come from monocytes processing hemoglobin. ECMO is associated with a highly variable, sustained increase in platelet, red-cell, and endothelial activation and injury that is a combination of circuit and transfusion related events, the patients underlying condition and possibly genetic influences on blood cell activation and injury. Extracellular vesicle measurements may improve our understanding of cellular activation and injury during ECMO as we work to improve the biocompatibility of these systems.

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.

Characterization of Circulating Extracellular Vesicle Surface Antigens in Patients With Primary Aldosteronism

[Figure: see text].

Epigenetic modifications and the development of kidney graft fibrosis

PURPOSE OF REVIEW

To outline recent discoveries in epigenetic regulatory mechanisms that have potential implications in the development of renal fibrosis following kidney transplantation.

RECENT FINDINGS

The characterization of renal fibrosis following kidney transplantation has shown TGFβ/Smad signaling to play a major role in the progression to chronic allograft dysfunction. The onset of unregulated proinflammatory pathways are only exacerbated by the decline in regulatory mechanisms lost with progressive patient age and comorbidities such as hypertension and diabetes. However, significant developments in the recognition of epigenetic regulatory markers upstream of aberrant TGFβ-signaling has significant clinical potential to provide therapeutic targets for the treatment of renal fibrosis. In addition, discoveries in extracellular vesicles and the characterization of their cargo has laid new framework for the potential to evaluate patient outcomes independent of invasive biopsies.

SUMMARY

The current review summarizes the main findings in epigenetic machinery specific to the development of renal fibrosis and highlights therapeutic options that have significant potential to translate into clinical practice.

Identification of Plexin D1 on circulating extracellular vesicles as a potential biomarker of polymyositis and dermatomyositis

OBJECTIVES

We aimed to identify disease-specific surface proteins on extracellular vesicles (EVs) as novel serum biomarkers of polymyositis and dermatomyositis (PM/DM).

METHODS

We performed liquid chromatography-tandem mass spectrometry (LC/MS) on purified EVs from sera of 10 PM/DM, 23 patients with other autoimmune diseases and 10 healthy controls (HC). We identified membrane proteins preferentially present in EVs of PM/DM patients by bioinformatics and biostatistical analyses. We developed EV sandwich ELISA for directly detecting serum EVs expressing disease-specific membrane proteins and evaluated their clinical utility using sera of 54 PM/DM, 24 rheumatoid arthritis (RA), 20 systemic lupus erythematosus (SLE), 13 systemic sclerosis, 25 Duchenne and Becker muscular dystrophy (DMD/BMD) patients, and 36 HC.

RESULTS

LC/MS analysis identified 1,220 proteins in serum EVs. Of these, Plexin D1 was enriched in those from PM/DM patients relative to HC or patients without PM/DM. Using a specific EV sandwich ELISA, we found that levels of Plexin D1-positive EVs (Plexin D1+ EVs) in serum were significantly greater in PM/DM patients than in HC, RA or SLE, or DMD/BMD patients. Serum levels of Plexin D1+ EVs were greater in those PM/DM patients with muscle pain or weakness. Serum levels of Plexin D1+ EVs were significantly correlated with levels of aldolase (rs=0.481), white blood cells (rs=0.381), neutrophils (rs=0.450), and platelets (rs=0.408) in PM/DM patients. Finally, serum levels of Plexin D1+ EVs decreased significantly in patients with PM/DM in clinical remission after treatment.

CONCLUSION

We have identified levels of circulating Plexin D1+ EVs as a novel serum biomarker for PM/DM.

Extracellular Vesicles in the Cornea: Insights from Other Tissues

Extracellular vesicles (EVs) are phospholipid bilayer-bound particles secreted by cells that have been found to be important in mediating cell-cell communication, signal transduction, and extracellular matrix remodeling. Their role in both physiological and pathological processes has been established in different tissues throughout the human body. The human cornea functions as a transparent and refractive barrier that protects the intraocular elements from the external environment. Injury, infection, or disease may cause the loss of corneal clarity by altering extracellular matrix organization within the stroma that may lead to detrimental effects on visual acuity. Over the years, numerous studies have identified many of the growth factors (e.g., transforming growth factor-β1, thrombospondin-1, and platelet-derived growth factor) important in corneal wound healing and scarring. However, the functional role of bound factors encapsulated in EVs in the context of corneal biology is less defined. In this review, we describe the discovery and characterization of EVs in the cornea. We focus on EV-matrix interactions, potential functions during corneal wound healing, and the bioactivity of mesenchymal stem cell-derived EVs. We also discuss the development of EVs as stable, drug-loaded therapeutics for ocular applications.

Exosomes in atrial fibrillation: therapeutic potential and role as clinical biomarkers

Atrial fibrillation (AF), the most common cardiac arrhythmia, is a global epidemic. AF can cause heart failure and myocardial infarction and increase the risk of stroke, disability, and thromboembolic events. AF is becoming increasingly ubiquitous and is associated with increased morbidity and mortality at higher ages, resulting in an increasing threat to human health as well as substantial medical and social costs. Currently, treatment strategies for AF focus on controlling heart rate and rhythm with medications to restore and maintain sinus rhythm, but this approach has limitations. Catheter ablation is not entirely satisfactory and does not address the issues underlying AF. Research exploring the mechanisms causing AF is urgently needed for improved prevention, diagnosis, and treatment of AF. Exosomes are small vesicles (30-150 nm) released by cells that transmit information between cells. MicroRNAs in exosomes play an important role in the pathogenesis of AF and are established as a biomarker for AF. In this review, a summary of the role of exosomes in AF is presented. The role of exosomes and microRNAs in AF occurrence, their therapeutic potential, and their potential role as clinical biomarkers is considered. A better understanding of exosomes has the potential to improve the prognosis of AF patients worldwide, reducing the global medical burden of this disease.

A Small Vimentin-Binding Molecule Blocks Cancer Exosome Release and Reduces Cancer Cell Mobility

Vimentin is an intermediate filament protein with diverse roles in health and disease far beyond its structural functions. Exosomes or small extracellular vesicles (sEVs) are key mediators for intercellular communication, contributing to tissue homeostasis and the progression of various diseases, especially the metastasis of cancers. In this study, we evaluated a novel vimentin-binding compound (R491) for its anti-cancer activities and its roles in cancer exosome release. The compound R491 induced a rapid and reversible intracellular vacuolization in various types of cancer cells. This phenotype did not result in an inhibition of cancer cell growth, which was consistent with our finding from a protein array that R491 did not reduce levels of major oncoproteins in cancer cells. Morphological and quantitative analyses on the intracellular vacuoles and extracellular exosomes revealed that in response to R491 treatment, the exosomes released from the cells were significantly reduced, while the exosomes retained as intra-luminal vesicles inside the cells were subsequently degraded. Vim^+/− cells had lower amounts of vimentin and accordingly, lower amounts of both the retained and the released exosomes than Vim^+/+ cells had, while the vimentin-binding compound R491 inhibited only the release of exosomes. Further functional tests showed that R491 significantly reduced the migration and invasion of cancer cells in vitro and decreased the amount of exosome in the blood in mice. Our study suggests that vimentin promotes exosome release, and small-molecule compounds that target vimentin are able to both block cancer exosome release and reduce cancer cell motility, and therefore could have potential applications for inhibiting cancer invasive growth.