MicroRNA-containing microvesicles regulating inflammation in association with atherosclerotic disease

MicroRNAs in extracellular vesicles: A potential role in cancer progression

Intercellular communication, an essential biological process in multicellular organisms, is mediated by direct cell-to-cell contact and cell secretary molecules. Emerging evidence identifies a third mechanism of intercellular communication- the release of extracellular vesicles (EVs). EVs are membrane-enclosed nanosized bodies, released from cells into the extracellular environment, often found in all biofluids. The growing body of research indicates that EVs carry bioactive molecules in the form of proteins, DNA, RNAs, microRNAs (miRNAs), lipids, metabolites, etc., and upon transferring them, alter the phenotypes of the target recipient cells. Interestingly, the abundance of EVs is found to be significantly higher in different diseased conditions, most importantly cancer. In the past few decades, numerous studies have identified EV miRNAs as an important contributor in the pathogenesis of different types of cancer. However, the underlying mechanism behind EV miRNA-associated cancer progression and how it could be used as a targeted therapy remain ill-defined. The present review highlights how EV miRNAs influence essential processes in cancer, such as growth, proliferation, metastasis, angiogenesis, apoptosis, stemness, immune evasion, resistance to therapy, etc. A special emphasis has been given to the potential role of EV miRNAs as cancer biomarkers. The final section of the review delineates the ongoing clinical trials on the role of miRNAs in the progression of different types of cancer. Targeting EV miRNAs could be a potential therapeutic means in the treatment of different forms of cancer alongside conventional therapeutic approaches.

Circulating extracellular microvesicles associated with electronic cigarette use increase endothelial cell inflammation and reduce nitric oxide production

The purpose of this study was to determine the effect of circulating microvesicles isolated from chronic electronic (e-)cigarette users on cultured human umbilical vein endothelial cell (HUVEC) expression of nuclear factor-κB (NF-κB), cellular cytokine release, phosphorylation of endothelial nitric oxide synthase (eNOS) and NO production. The HUVECs were treated with microvesicles isolated via flow cytometry from nine non-tobacco users (five male and four female; 22 ± 2 years of age) and 10 e-cigarette users (six male and four female; 22 ± 2 years of age). Microvesicles from e-cigarette users induced significantly greater release of interleukin-6 (183.4 ± 23.6 vs. 150.6 ± 15.4 pg/mL; P = 0.002) and interleukin-8 (160.0 ± 31.6 vs. 129.4 ± 11.2 pg/mL; P = 0.01), in addition to expression of p-NF-κB p65 (Ser536) (18.8 ± 3.4 vs. 15.6 ± 1.5 a.u.; P = 0.02) from HUVECs compared with microvesicles from non-tobacco users. Nuclear factor-κB p65 was not significantly different between microvesicles from the non-tobacco users and from the e-cigarette users (87.6 ± 8.7 vs. 90.4 ± 24.6 a.u.; P = 0.701). Neither total eNOS (71.4 ± 21.8 vs. 80.4 ± 24.5 a.u.; P = 0.413) nor p-eNOS (Thr495) (229.2 ± 26.5 vs. 222.1 ± 22.7 a.u.; P = 0.542) was significantly different between microvesicle-treated HUVECs from non-tobacco users and e-cigarette users. However, p-eNOS (Ser1177) (28.9 ± 6.2 vs. 45.8 ± 9.0 a.u.; P < 0.001) expression was significantly lower from e-cigarette users compared with non-tobacco users. Nitric oxide production was significantly lower (8.2 ± 0.6 vs. 9.7 ± 0.9 μmol/L; P = 0.001) in HUVECs treated with microvesicles from e-cigarette users compared with microvesicles from non-tobacco users. This study demonstrated increased NF-κB activation and inflammatory cytokine production, in addition to diminished eNOS activity and NO production resulting from e-cigarette use. HIGHLIGHTS: What is the central question of this study? Circulating microvesicles contribute to cardiovascular health and disease via their effects on the vascular endothelium. The impact of electronic (e-)cigarette use on circulating microvesicle phenotype is not well understood. What is the main finding and its importance? Circulating microvesicles from e-cigarette users increase endothelial cell inflammation and impair endothelial nitric oxide production. Endothelial inflammation and diminished nitric oxide bioavailability are central factors underlying endothelial dysfunction and, in turn, cardiovascular disease risk. Deleterious changes in the functional phenotype of circulating microvesicles might contribute to the reported adverse effects of e-cigarette use on cardiovascular health.

Exosomes based strategies for cardiovascular diseases: Opportunities and challenges

Exosomes, as nanoscale extracellular vesicles (EVs), are secreted by all types of cells to facilitate intercellular communication in living organisms. After being taken up by neighboring or distant cells, exosomes can alter the expression levels of target genes in recipient cells and thereby affect their pathophysiological outcomes depending on payloads encapsulated therein. The functions and mechanisms of exosomes in cardiovascular diseases have attracted much attention in recent years and are thought to have cardioprotective and regenerative potential. This review summarizes the biogenesis and molecular contents of exosomes and details the roles played by exosomes released from various cells in the progression and recovery of cardiovascular disease. The review also discusses the current status of traditional exosomes in cardiovascular tissue engineering and regenerative medicine, pointing out several limitations in their application. It emphasizes that some of the existing emerging industrial or bioengineering technologies are promising to compensate for these shortcomings, and the combined application of exosomes and biomaterials provides an opportunity for mutual enhancement of their performance. The integration of exosome-based cell-free diagnostic and therapeutic options will contribute to the further development of cardiovascular regenerative medicine.

Targeted drug delivery of engineered mesenchymal stem/stromal-cell-derived exosomes in cardiovascular disease: recent trends and future perspectives

In recent years, stem cells and their secretomes, notably exosomes, have received considerable attention in biomedical applications. Exosomes are cellular secretomes used for intercellular communication. They perform the function of intercellular messengers by facilitating the transport of proteins, lipids, nucleic acids, and therapeutic substances. Their biocompatibility, minimal immunogenicity, targetability, stability, and engineerable characteristics have additionally led to their application as drug delivery vehicles. The therapeutic efficacy of exosomes can be improved through surface modification employing functional molecules, including aptamers, antibodies, and peptides. Given their potential as targeted delivery vehicles to enhance the efficiency of treatment while minimizing adverse effects, exosomes exhibit considerable promise. Stem cells are considered advantageous sources of exosomes due to their distinctive characteristics, including regenerative and self-renewal capabilities, which make them well-suited for transplantation into injured tissues, hence promoting tissue regeneration. However, there are notable obstacles that need to be addressed, including immune rejection and ethical problems. Exosomes produced from stem cells have been thoroughly studied as a cell-free strategy that avoids many of the difficulties involved with cell-based therapy for tissue regeneration and cancer treatment. This review provides an in-depth summary and analysis of the existing knowledge regarding exosomes, including their engineering and cardiovascular disease (CVD) treatment applications.

Effects of circulating endothelial microvesicles isolated from adults with obesity on endothelial cell inflammation, apoptosis, and nitric oxide production

Circulating endothelial cell-derived microvesicles (EMVs) have been shown to be elevated with obesity and associated with endothelial dysfunction; however, their direct effect on endothelial cells is unknown. The experimental aim of this study was to determine the effect of EMVs isolated from adults with obesity on endothelial cell inflammation, apoptosis, and nitric oxide (NO) production. EMVs (CD144+ microvesicles) were identified, enumerated, and isolated from plasma by flow cytometry from 24 sedentary adults: 12 normal-weight adults [8 M/4 F; age: 55 ± 6 yr; body mass index (BMI): 24.3 ± 0.7 kg/m2; EMV: 144 ± 53 EMVs/µL] and 12 adults with obesity (6 M/6 F; 59 ± 7 yr; BMI: 31.0 ± 1.1 kg/m2; EMV: 245 ± 89 EMVs/µL). Human umbilical vein endothelial cells were cultured and treated with EMVs from either normal-weight adults or adults with obesity. EMVs from obese adults induced significantly higher release of interleukin (IL)-6 (108.2 ± 7.7 vs. 90.9 ± 10.0 pg/mL) and IL-8 (75.4 ± 9.8 vs. 59.5 ± 11.5 pg/mL) from endothelial cells vs. EMVs from normal-weight adults, concordant with greater intracellular expression of phosphorylated NF-κB p65 (Ser536; active NF-κB) [145.0 ± 34.1 vs. 114.5 ± 30.4 arbitrary units (AU)]. Expression of phosphorylated p38-MAPK (15.4 ± 5.7 vs. 9.2 ± 2.5 AU) and active caspase-3 (168.2 ± 65.5 vs. 107.8 ± 40.5 AU), markers of cell apoptosis, was higher in cells treated with obesity-related EMVs. Phosphorylated endothelial nitric oxide synthase (eNOS) (Ser1177) expression (23.5 ± 7.2 vs. 34.7 ± 9.7 AU) and NO production (6.9 ± 1.4 vs. 8.7 ± 0.7 µmol/L) were significantly lower in the cells treated with EMVs from obese adults. These data indicate that circulating EMVs from adults with obesity promote a proinflammatory, proapoptotic, and NO-compromised endothelial phenotype. Circulating EMVs are a potential mediator of obesity-related endothelial dysfunction.NEW & NOTEWORTHY In the present study, we determined the effect of circulating endothelial cell-derived microvesicles (EMVs) isolated from adults with obesity on endothelial cell inflammation, apoptosis, and nitric oxide (NO) production in vitro. Circulating EMVs harvested from adults with obesity promoted a proinflammatory, proapoptotic, and NO-compromised endothelial phenotype. Elevated circulating EMVs in adults with obesity, independent of other cardiometabolic risk factors, are a potential novel systemic mediator of obesity-related endothelial dysfunction and vascular risk.

Aging and Metabolic Reprogramming of Adipose-Derived Stem Cells Affect Molecular Mechanisms Related to Cardiovascular Diseases

We performed a systematic search of the PubMed database for English-language articles related to the function of adipose-derived stem cells in the pathogenesis of cardiovascular diseases. In preclinical models, adipose-derived stem cells protected arteries and the heart from oxidative stress and inflammation and preserved angiogenesis. However, clinical trials did not reiterate successful treatments with these cells in preclinical models. The low success in patients may be due to aging and metabolic reprogramming associated with the loss of proliferation capacity and increased senescence of stem cells, loss of mitochondrial function, increased oxidative stress and inflammation, and adipogenesis with increased lipid deposition associated with the low potential to induce endothelial cell function and angiogenesis, cardiomyocyte survival, and restore heart function. Then, we identify noncoding RNAs that may be mechanistically related to these dysfunctions of human adipose-derived stem cells. In particular, a decrease in let-7, miR-17-92, miR-21, miR-145, and miR-221 led to the loss of their function with obesity, type 2 diabetes, oxidative stress, and inflammation. An increase in miR-34a, miR-486-5p, and mir-24-3p contributed to the loss of function, with a noteworthy increase in miR-34a with age. In contrast, miR-146a and miR-210 may protect stem cells. However, a systematic analysis of other noncoding RNAs in human adipose-derived stem cells is warranted. Overall, this review gives insight into modes to improve the functionality of human adipose-derived stem cells.

Non-Intrinsic, Systemic Mechanisms of Cellular Senescence

Cellular senescence is believed to contribute to aging and disease through the activity of secreted factors that promote inflammation, remodel the extracellular matrix, and adversely modify the behavior of non-senescent cells. While the markers and properties of senescent cells are still under investigation, it is postulated that cellular senescence manifests in vivo as the consequence of cellular damage that accumulates and becomes exacerbated with time. Yet, the notions that senescence has a solely intrinsic and time-dependent nature are questioned by the rapid induction of senescence in young mice and young cells in vitro by exposure to blood from aged animals. Here, we review some of the research on the systemically present factors that increase with age and may contribute to extrinsically induced senescence or "bystander senescence". These include proteins, reactive oxygen species, lipids, and nucleic acids, which may be present in individual soluble form, in vesicles, and in non-membranous multi-component macromolecules.

Role of lipid signalling in extracellular vesicles-mediated cell-to-cell communication

Lipid signalling plays a crucial role in extracellular vesicle (EV)-mediated cell-to-cell communication. Extracellular vesicles are small membrane-bound structures released by various cell types into the extracellular environment. They include exosomes, microvesicles, and apoptotic bodies. These vesicles contain a variety of bioactive molecules, including proteins, nucleic acids (such as miRNAs and mRNAs), and lipids. Lipids are important components of EVs and are involved in various aspects of their biogenesis, cargo sorting, and functional effects on target cells. In this review, we will discuss how lipid signalling is involved in EV-mediated cell-to-cell communication. In summary, lipid signalling is intricately involved in extracellular vesicle-mediated cell-to-cell communication. The lipid composition of EVs influences their biogenesis, cargo sorting, interactions with target cells, and functional effects on recipient cells. Understanding the role of lipids in EV-mediated communication is essential for deciphering the mechanisms underlying intercellular signalling and developing potential therapeutic strategies based on EVs.

Tumor cell-derived exosomes regulate macrophage polarization: Emerging directions in the study of tumor genesis and development

As an extracellular vesicle, exosomes play an important role in intercellular information transmission, delivering cargos of the parent cell, such as RNA, DNA, proteins, and lipids, activating different signaling pathways in the target cell and regulating inflammation, angiogenesis, and tumor progression. In particular, exosomes secreted by tumor cells can change the function of surrounding cells, creating a microenvironment conducive to tumor growth and metastasis. For example, after macrophages phagocytose exosomes and accept their cargos, they activate macrophage polarization-related signaling pathways and polarize macrophages into M1 or M2 types to exert antitumor or protumor functions. Currently, the study of exosomes affecting the polarization of macrophages has attracted increasing attention. Therefore, this paper reviews relevant studies in this field to better understand the mechanism of exosome-induced macrophage polarization and provide evidence for exploring novel targets for tumor therapy and new diagnostic markers in the future.

Phylogeny and expression of tetraspanin CD9 paralogues in rainbow trout (Oncorhynchus mykiss)

CD9 is a member of the tetraspanin family, which is characterised by a unique domain structure and conserved motifs. In mammals, CD9 is found in tetraspanin-enriched microdomains (TEMs) on the surface of virtually every cell type. CD9 has a wide variety of roles, including functions within the immune system. Here we show the first in-depth analysis of the cd9 gene family in salmonids, showing that this gene has expanded to six paralogues in three groups (cd9a, cd9b, cd9c) through whole genome duplication events. We suggest that through genome duplications, cd9 has undergone subfunctionalisation in the paralogues and that cd9c1 and cd9c2 in particular are involved in antiviral responses in salmonid fish. We show that these paralogues are significantly upregulated in parallel to classic interferon-stimulated genes (ISGs) active in the antiviral response. Expression analysis of cd9 may therefore become an interesting target to assess teleost responses to viruses.

Endothelial-derived extracellular vesicles from obese/hypertensive adults increase factors associated with hypertrophy and fibrosis in cardiomyocytes

Obesity and hypertension, independently and combined, are associated with increased risk of heart failure and heart failure-related morbidity and mortality. Interest in circulating endothelial cell-derived microvesicles (EMVs) has intensified because of their involvement in the development and progression of endothelial dysfunction, atherosclerosis, and cardiomyopathy. The experimental aim of this study was to determine, in vitro, the effects of EMVs isolated from obese/hypertensive adults on key proteins regulating cardiomyocyte hypertrophy [cardiac troponin T (cTnT), α-actinin, nuclear factor-kB (NF-kB)] and fibrosis [transforming growth factor (TGF)-β, collagen1-α1], as well as endothelial nitric oxide synthase (eNOS) expression and nitric oxide (NO) production. EMVs (CD144+ microvesicles) were isolated from plasma by flow cytometry in 12 normal weight/normotensive [8 males/4 females; age: 56 ± 5 yr; body mass index (BMI): 23.3 ± 2.0 kg/m2; blood pressure (BP): 117/74 ± 4/5 mmHg] and 12 obese/hypertensive (8 males/4 females; 57 ± 5 yr; 31.7 ± 1.8 kg/m2; 138/83 ± 8/7 mmHg) adults. Human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were cultured and treated with EMVs from either normal weight/normotensive or obese/hypertensive adults for 24 h. Expression of cTnT (64.1 ± 13.9 vs. 29.5 ± 7.8 AU), α-actinin (66.0 ± 14.7 vs. 36.2 ± 10.3 AU), NF-kB (166.3 ± 13.3 vs. 149.5 ± 8.8 AU), phosphorylated-NF-kB (226.1 ± 25.2 vs. 179.1 ± 25.5 AU), and TGF-β (62.1 ± 13.3 vs. 23.5 ± 8.8 AU) were significantly higher and eNOS activation (16.4 ± 4.3 vs. 24.8 ± 3.7 AU) and nitric oxide production (6.8 ± 1.2 vs. 9.6 ± 1.3 µmol/L) were significantly lower in iPSC-CMs treated with EMVs from obese/hypertensive compared with normal weight/normotensive adults. These data indicate that EMVs from obese/hypertensive adults induce a cardiomyocyte phenotype prone to hypertrophy, fibrosis, and reduced nitric oxide production, central factors associated with heart failure risk and development.NEW & NOTEWORTHY In the present study we determined the effect of endothelial microvesicles (EMVs) isolated from obese/hypertensive adults on mediators of cardiomyocyte hypertrophy [cardiac troponin T (cTnT), α-actinin, nuclear factor-kB (NF-kB)] and fibrosis [transforming growth factor (TGF-β), collagen1-α1] as well as endothelial nitric oxide synthase (eNOS) expression and NO production. EMVs from obese/hypertensive induced significantly higher expression of hypertrophic (cTnT, α-actinin, NF-kB) and fibrotic (TGF-β) proteins as well as significantly lower eNOS activation and NO production in cardiomyocytes than EMVs from normal weight/normotensive adults. EMVs are a potential mediating factor in the increased risk of cardiomyopathy and heart failure with obesity/hypertension.

Noncoding RNAs Controlling Oxidative Stress in Cancer

Mitochondria in cancer cells tend to overproduce reactive oxygen species (ROS), inducing a vicious cycle between mitochondria, ROS, genomic instability, and cancer development. The first part of this review deals with the role of noncoding RNAs in regulating mitochondrial ROS production and the expression of antioxidants in cancer cells, preventing the increase of ROS in the tumor microenvironment. In addition, cytotoxic T and natural killer cells release high levels of ROS, inducing cell death, while anti-immune regulatory T cells, tumor-associated M2 macrophages, and myeloid-derived suppressor cells, at least at the initial stage of tumor growth, release low levels of ROS supporting tumor growth. Therefore, this review's second part deals with noncoding RNAs' role in regulating the metabolic reprogramming of immune cells about ROS release. Furthermore, the enrichment of noncoding RNAs in microvesicles allows communication between cell types in a tumor and between a tumor and tumor-adjacent tissues. Therefore, the third part illustrates how noncoding RNA-containing microvesicles secreted by mesenchymal stem cells and primary tumor cells may primarily aid the shift of immune cells to a pro-oncogenic phenotype. Conversely, microvesicles released by tumor-adjacent tissues may have the opposite effect. Our review reveals that a specific noncoding RNA may affect oxidative stress by several mechanisms, which may have opposite effects on tumor growth. Furthermore, they may be involved in mechanisms other than regulating oxidative stress, which may level out their effects on oxidative stress and tumor growth. In addition, several noncoding RNAs might share a specific function, making it very unlikely that intervening with only one of these noncoding RNAs will block this particular mechanism. Overall, further validation of the interaction between noncoding RNAs about cancer types and stages of tumor development is warranted.

Advances in the Study of Exosomes as Drug Delivery Systems for Bone-Related Diseases

Bone-related diseases are major problems and heavy burdens faced by modern society. Current clinical approaches for the treatment of these pathological conditions often lead to complications and have limited therapeutic efficacy. In this context, the development of nanotherapeutic platforms, such as extracellular vesicles, can improve the relevant therapeutic effects. In particular, exosomes are nano-sized, lipid bilayer extracellular vesicles secreted by many cells in mammals. Due to their innate capacity to transport materials-including proteins, lipids, and genes-among cells, as well as their innate attraction to target cells, they are considered to be a crucial medium for cell communication and are involved in a number of biological processes. Exosomes have been used as drug delivery vehicles in recent bone tissue engineering studies, in order to regulate bone homeostasis. However, the precise workings of the exosome regulatory network in maintaining bone homeostasis and its potential for treating bone injury remain unclear. To provide a fresh perspective for the study of exosomes in drug delivery and bone-related diseases, in this paper, we review recent studies on the roles of exosomes for drug delivery in bone homeostasis and bone-related diseases, as well as the composition and characteristics of exosomes and their regulatory roles in bone homeostasis and bone-related diseases, aiming to provide new ideas for the therapeutic application of exosomes in the treatment of bone-related diseases.

Impact of the flame retardant 2,2'4,4'-tetrabromodiphenyl ether (PBDE-47) in THP-1 macrophage-like cell function via small extracellular vesicles

2,2'4,4'-tetrabromodiphenyl ether (PBDE-47) is one of the most widespread environmental brominated flame-retardant congeners which has also been detected in animal and human tissues. Several studies have reported the effects of PBDEs on different health issues, including neurobehavioral and developmental disorders, reproductive health, and alterations of thyroid function. Much less is known about its immunotoxicity. The aim of our study was to investigate the effects that treatment of THP-1 macrophage-like cells with PBDE-47 could have on the content of small extracellular vesicles' (sEVs) microRNA (miRNA) cargo and their downstream effects on bystander macrophages. To achieve this, we purified sEVs from PBDE-47 treated M(LPS) THP-1 macrophage-like cells (sEVs^PBDE+LPS) by means of ultra-centrifugation and characterized their miRNA cargo by microarray analysis detecting the modulation of 18 miRNAs. Furthermore, resting THP-1 derived M(0) macrophage-like cells were cultured with sEVs^PBDE+LPS, showing that the treatment reshaped the miRNA profiles of 12 intracellular miRNAs. This dataset was studied in silico, identifying the biological pathways affected by these target genes. This analysis identified 12 pathways all involved in the maturation and polarization of macrophages. Therefore, to evaluate whether sEVs^PBDE+LPS can have some immunomodulatory activity, naïve M(0) THP-1 macrophage-like cells cultured with purified sEVs^PBDE+LPS were studied for IL-6, TNF-α and TGF-β mRNAs expression and immune stained with the HLA-DR, CD80, CCR7, CD38 and CD209 antigens and analyzed by flow cytometry. This analysis showed that the PBDE-47 treatment does not induce the expression of specific M1 and M2 cytokine markers of differentiation and may have impaired the ability to make immunological synapses and present antigens, down-regulating the expression of HLA-DR and CD209 antigens. Overall, our study supports the model that perturbation of miRNA cargo by PBDE-47 treatment contributes to the rewiring of cellular regulatory pathways capable of inducing perturbation of differentiation markers on naïve resting M(0) THP-1 macrophage-like cells.

Prospective Advances of Extracellular Vesicles Investigation in Cardiovascular and Metabolic Research

Extracellular vesicles (EVs) play an important role in cardiovascular and metabolic diseases through intercellular communication. Although there has been extensive research on EVs, there are still some unsolved problems in the technologies of investigation of EVs. In this chapter, we reviewed the current knowledge of EVs functions in cardiovascular and metabolic pathophysiology and EVs as biomarkers and therapeutic agents in cardiovascular and metabolic diseases. We also addressed the challenges in isolation and identification of EVs as well as challenges in visualization and tracking of EVs. By addressing these challenges, we hope to have a more in-depth understanding of the biological functions of EVs.

Exosomes in pathogenesis, diagnosis, and therapy of ischemic stroke

Ischemic stroke is one of the major contributors to death and disability worldwide. Thus, there is an urgent need to develop early brain tissue perfusion therapies following acute stroke and to enhance functional recovery in stroke survivors. The morbidity, therapy, and recovery processes are highly orchestrated interactions involving the brain with other tissues. Exosomes are natural and ideal mediators of intercellular information transfer and recognized as biomarkers for disease diagnosis and prognosis. Changes in exosome contents express throughout the physiological process. Accumulating evidence demonstrates the use of exosomes in exploring unknown cellular and molecular mechanisms of intercellular communication and organ homeostasis and indicates their potential role in ischemic stroke. Inspired by the unique properties of exosomes, this review focuses on the communication, diagnosis, and therapeutic role of various derived exosomes, and their development and challenges for the treatment of cerebral ischemic stroke.

Recent advances in targeted delivery of non-coding RNA-based therapeutics for atherosclerosis

Cardiovascular disease (CVD) has overtaken infectious illnesses as the leading cause of mortality and disability worldwide. The pathology that underpins CVD is atherosclerosis, characterized by chronic inflammation caused by the accumulation of plaques in the arteries. As our knowledge about the microenvironment of blood vessel walls deepens, there is an opportunity to fine-tune treatments to target the mechanisms driving atherosclerosis more directly. The application of non-coding RNAs (ncRNAs) as biomarkers or intervention targets is increasing. Although these ncRNAs play an important role in driving atherosclerosis and vascular dysfunction, the cellular and extracellular environments pose a challenge for targeted transmission and therapeutic regulation of ncRNAs. Specificity, delivery, and tolerance have hampered the clinical translation of ncRNA-based therapeutics. Nanomedicine is an emerging field that uses nanotechnology for targeted drug delivery and advanced imaging. Recently, nanoscale carriers have shown promising results and have introduced new possibilities for nucleic acid targeted drug delivery, particularly for atherosclerosis. In this review, we discuss the latest developments in nanoparticles to aid ncRNA-based drug development, particularly miRNA, and we analyze the current challenges in ncRNA targeted delivery. In particular, we highlight the emergence of various kinds of nanotherapeutic approaches based on ncRNAs, which can improve treatment options for atherosclerosis.

Platelet-derived extracellular vesicles encapsulate microRNA-34c-5p to ameliorate inflammatory response of coronary artery endothelial cells via PODXL-mediated P38 MAPK signaling pathway

BACKGROUND AND AIMS

Low-grade chronic inflammation was reported to serve as a distinctive pathophysiologic feature of coronary artery disease (CAD), the leading cause of death around the world. Herein, the current study aimed to explore whether and how microRNA-34c-5p (miR-34c-5p), a miRNA enriched in extracellular vesicles (EVs) originated from the activated platelet (PLT-EVs), affects the inflammation of human coronary artery endothelial cells (HCAECs).

METHODS AND RESULTS

HCAECs were established as an in vitro cell model using oxidized low-density lipoprotein (ox-LDL). miR-34c-5p, an abundant miRNA in PLT-EVs, can be transferred to HCAECs and target PODXL by binding to its 3'UTR. Gain- and loss-of-function experiments of miR-34c-5p and podocalyxin (PODXL) were performed in ox-LDL-induced HCAECs. Subsequently, HCAECs were subjected to co-culture with PLT-EVs, followed by detection of the expression patterns of key pro-inflammatory factors. Either miR-34c-5p mimic or PLT-EVs harboring miR-34c-5p attenuated the ox-LDL-evoked inflammation in HCAECs by suppressing interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α). By blocking the P38 MAPK signaling pathway, miR-34c-5p-mediated depletion of PODXL contributed to protection against ox-LDL-induced inflammation. In vitro findings were further validated by findings observed in ApoE knock-out mice. Additionally, miR-34c-5p in PLT-EVs showed an athero-protective role in the murine model.

CONCLUSION

Altogether, our findings highlighted that miR-34c-5p in PLT-EVs could alleviate inflammation response in HCAECs by targeting PODXL and inactivation of the P38 MAPK signaling pathway.

Extracellular vesicles in vascular remodeling

Vascular remodeling contributes to the development of a variety of vascular diseases including hypertension and atherosclerosis. Phenotypic transformation of vascular cells, oxidative stress, inflammation and vascular calcification are closely associated with vascular remodeling. Extracellular vesicles (EVs) are naturally released from almost all types of cells and can be detected in nearly all body fluids including blood and urine. EVs affect vascular oxidative stress, inflammation, calcification, and lipid plaque formation; and thereby impact vascular remodeling in a variety of cardiovascular diseases. EVs may be used as biomarkers for diagnosis and prognosis, and therapeutic strategies for vascular remodeling and cardiovascular diseases. This review includes a comprehensive analysis of the roles of EVs in the vascular remodeling in vascular diseases, and the prospects of EVs in the diagnosis and treatment of vascular diseases.

Platelet extracellular vesicles and the secretory interactome join forces in health and disease

Extracellular vesicles (EVs) are small membrane-bound vesicles released by cells under various conditions. They are found in the extracellular milieu in all biological fluids. As the concentrations, contents, and origin of EVs can change during inflammation, the assessment of EVs can be used as a proxy of cellular activation. Here, we review the literature regarding EVs, more particularly those released by platelets and their mother cells, the megakaryocytes. Their cargo includes cytokines, growth factors, organelles (mitochondria and proteasomes), nucleic acids (messenger and non-coding RNA), transcription factors, and autoantigens. EVs may thus contribute to intercellular communication by facilitating exchange of material between cells. EVs also interact with other molecules secreted by cells. In autoimmune diseases, EVs are associated with antibodies secreted by B cells. By definition, EVs necessarily comprise a phospholipid moiety, which is thus the target of secreted phospholipases also abundantly expressed in the extracellular milieu. We discuss how platelet-derived EVs, which represent the majority of the circulating EVs, may contribute to immunity through the activity of their cargo or in combination with the secretory interactome.

Role of endothelial cells in vascular calcification

Vascular calcification (VC) is active and regulates extraosseous ossification progress, which is an independent predictor of cardiovascular disease (CVD) morbidity and mortality. Endothelial cells (ECs) line the innermost layer of blood vessels and directly respond to changes in flow shear stress and blood composition. Together with vascular smooth muscle cells, ECs maintain vascular homeostasis. Increased evidence shows that ECs have irreplaceable roles in VC due to their high plasticity. Endothelial progenitor cells, oxidative stress, inflammation, autocrine and paracrine functions, mechanotransduction, endothelial-to-mesenchymal transition (EndMT), and other factors prompt ECs to participate in VC. EndMT is a dedifferentiation process by which ECs lose their cell lineage and acquire other cell lineages; this progress coexists in both embryonic development and CVD. EndMT is regulated by several signaling molecules and transcription factors and ultimately mediates VC via osteogenic differentiation. The specific molecular mechanism of EndMT remains unclear. Can EndMT be reversed to treat VC? To address this and other questions, this study reviews the pathogenesis and research progress of VC, expounds the role of ECs in VC, and focuses on the regulatory factors underlying EndMT, with a view to providing new concepts for VC prevention and treatment.

Mesenchymal Stem Cell-Derived Exosomes and Intervertebral Disc Regeneration: Review

Intervertebral disc degeneration (IVDD) is a common cause of lower back pain (LBP), which burdens individuals and society as a whole. IVDD occurs as a result of aging, mechanical trauma, lifestyle factors, and certain genetic abnormalities, leads to loss of nucleus pulposus, alteration in the composition of the extracellular matrix, excessive oxidative stress, and inflammation in the intervertebral disc. Pharmacological and surgical interventions are considered a boon for the treatment of IVDD, but the effectiveness of those strategies is limited. Mesenchymal stem cells (MSCs) have recently emerged as a possible promising regenerative therapy for IVDD due to their paracrine effect, restoration of the degenerated cells, and capacity for differentiation into disc cells. Recent investigations have shown that the pleiotropic effect of MSCs is not related to differentiation capacity but is mediated by the secretion of soluble paracrine factors. Early studies have demonstrated that MSC-derived exosomes have therapeutic potential for treating IVDD by promoting cell proliferation, tissue regeneration, modulation of the inflammatory response, and reduced apoptosis. This paper highlights the current state of MSC-derived exosomes in the field of treatment of IVDD with further possible future developments, applications, and challenges.

Effect of Extracellular Vesicles From Multiple Cells on Vascular Smooth Muscle Cells in Atherosclerosis

Atherosclerosis (AS)-related diseases are still the main cause of death in clinical patients. The phenotype switching, proliferation, migration, and secretion of vascular smooth muscle cells (VSMCs) have a pivotal role in atherosclerosis. Although numerous research studies have elucidated the role of VSMCs in AS, their potential functional regulations continue to be explored. The formation of AS involves various cells, such as endothelial cells, smooth muscle cells, and macrophages. Therefore, intercellular communication of blood vessels cannot be ignored due to closely connected endothelia, media, and adventitia. Extracellular vesicles (EVs), as the vectors of cell-to-cell communication, can deliver proteins and nucleic acids of parent cells to the recipient cells. EVs have emerged as being central in intercellular communication and play a vital role in the pathophysiologic mechanisms of AS. This review summarizes the effects of extracellular vesicles (EVs) derived from multiple cells (endothelial cells, macrophages, mesenchymal stem cells, etc.) on VSMCs in AS. The key findings of this review are as follows: 1) endothelial cell–derived EVs (EEVs) have anti- or pro-atherogenic effects on VSMCs; 2) macrophage-derived EVs (MEVs) aggravate the proliferation and migration of VSMCs; 3) mesenchymal stem cells can inhibit VSMCs; and 4) the proliferation and migration of VSMCs can be inhibited by the treatment of EVs with atherosclerosis-protective factors and promoted by noxious stimulants. These results suggested that EVs have the same functional properties as treated parent cells, which might provide vital guidance for treating AS.

Microvesicle-Mediated Communication Within the Alveolar Space: Mechanisms of Uptake by Epithelial Cells and Alveolar Macrophages

Intra-alveolar microvesicles (MVs) are important mediators of inter-cellular communication within the alveolar space, and are key components in the pathophysiology of lung inflammation such as acute respiratory distress syndrome (ARDS). Despite the abundance of data detailing the pro-inflammatory effects of MVs, it remains unclear how MVs interact or signal with target cells in the alveolus. Using both in vivo and in vitro alveolar models, we analyzed the dynamics of MV uptake by resident alveolar cells: alveolar macrophages and epithelial cells. Under resting conditions, the overwhelming majority of MVs were taken up by alveolar macrophages. However, following lipopolysaccharide (LPS)-mediated inflammation, epithelial cells internalized significantly more MVs (p<0.01) whilst alveolar macrophage internalization was significantly reduced (p<0.01). We found that alveolar macrophages adopted a pro-inflammatory phenotype after internalizing MVs under resting conditions, but reduction of MV uptake following LPS pre-treatment was associated with loss of inflammatory phenotype. Instead, MVs induced significant epithelial cell inflammation following LPS pre-treatment, when MV internalization was most significant. Using pharmacological inhibitors, we interrogated the mechanisms of MV internalization to identify which endocytic pathways and cell surface receptors are involved. We demonstrated that epithelial cells are exclusively dependent on the clathrin and caveolin dependent endocytotic pathway, whereas alveolar macrophage uptake may involve a significant phagocytic component. Furthermore, alveolar macrophages predominantly engulf MVs via scavenger receptors whilst, epithelial cells internalize MVs via a phosphatidylserine/integrin receptor mediated pathway (specifically alpha V beta III), which can be inhibited with phosphatidylserine-binding protein (i.e. annexin V). In summary, we have undertaken a comprehensive evaluation of MV internalization within the alveolar space. Our results demonstrate that different environmental conditions can modulate MV internalization, with inflammatory stimuli strongly enhancing epithelial cell uptake of MVs and inducing epithelial cell activation. Our data reveal the unique mechanisms by which alveolar macrophages and epithelial cells internalize MVs thereby elucidating how MVs exert their pathophysiological effect during lung inflammation and injury. As MVs are potential novel therapeutic targets in conditions such as ARDS, these data provide crucial insights into the dynamics of MV-target cell interactions and highlight potential avenues for researchers to modulate and inhibit their pro-inflammatory actions within the alveolar space.

Circulating serum microRNAs including senescent miR-31-5p are associated with incident fragility fractures in older postmenopausal women with type 2 diabetes mellitus

Fragility fractures are an important hallmark of aging and an increasingly recognized complication of Type 2 diabetes (T2D). T2D individuals have been found to exhibit an increased fracture risk despite elevated bone mineral density (BMD) by dual x-ray absorptiometry (DXA). However, BMD and FRAX-scores tend to underestimate fracture risk in T2D. New, reliable biomarkers are therefore needed. MicroRNAs (miRNAs) are secreted into the circulation from cells of various tissues proportional to local disease severity. Serum miRNA-classifiers were recently found to discriminate T2D women with and without prevalent fragility fractures with high specificity and sensitivity (AUC > 0.90). However, the association of circulating miRNAs with incident fractures in T2D has not been examined yet. In 168 T2D postmenopausal women in the AGES-Reykjavik cohort, miRNAs were extracted from baseline serum and a panel of 10 circulating miRNAs known to be involved in diabetic bone disease and aging was quantified by qPCR and Ct-values extracted. Unadjusted and adjusted Cox proportional hazard models assessed the associations between serum miRNAs and incident fragility fracture. Additionally, Receiver operating curve (ROC) analyses were performed. Of the included 168 T2D postmenopausal women who were on average 77.2 ± 5.6 years old, 70 experienced at least one incident fragility fracture during the mean follow-up of 5.8 ± 2.7 years. We found that 3 serum miRNAs were significantly associated with incident diabetic fragility fracture: while low expression of miR-19b-1-5p was associated with significantly lower risk of incident fragility fracture (HR 0.84 (95% CI: 0.71-0.99, p = 0.0323)), low expression of miR-203a and miR-31-5p was each significantly associated with a higher risk of incident fragility fracture per unit increase in Ct-value (miR-203a: HR 1.29 (95% CI: 1.12-1.49), p = 0.0004, miR-31-5p HR 1.27 (95% CI: 1.06-1.52), p = 0.009). Hazard ratios of the latter two miRNAs remained significant after adjustments for age, body mass index (BMI), areal bone mineral density (aBMD), clinical FRAX or FRAXaBMD. Women with miR-203a and miR-31-5p serum levels in the lowest expression quartiles exhibited a 2.4-3.4-fold larger fracture risk than women with miR-31-5p and miR-203a serum expressions in the highest expression quartile (0.002 ≤ p ≤ 0.039). Women with both miR-203a and miR-31-5p serum levels below the median had a significantly increased fracture risk (Unadjusted HR 3.26 (95% CI: 1.57-6.78, p = 0.001) compared to those with both expression levels above the median, stable to adjustments. We next built a diabetic fragility signature consisting of the 3 miRNAs that showed the largest associations with incident fracture (miR-203a, miR-31-5p, miR-19b-1-5p). This 3-miRNA signature showed with an AUC of 0.722 comparable diagnostic accuracy in identifying incident fractures to any of the clinical parameters such as aBMD, Clinical FRAX or FRAXaBMD alone. When the 3 miRNAs were combined with aBMD, this combined 4-feature signature performed with an AUC of 0.756 (95% CI: 0.680, 0.823) significantly better than aBMD alone (AUC 0.666, 95% CI: 0.585, 0.741) (p = 0.009). Our data indicate that specific serum microRNAs including senescent miR-31-5p are associated with incident fragility fracture in older diabetic women and can significantly improve fracture risk prediction in diabetics when combined with aBMD measurements of the femoral neck.

Message in a Bottle: Endothelial Cell Regulation by Extracellular Vesicles

Simple Summary

Elucidating the role of extracellular vesicles (EVs) in the communication mechanisms between cancer and endothelial cells (ECs) within the tumor microenvironment is an exciting challenge. At the same time, due to their ability to convey bioactive molecules, EVs may be potentially relevant from a therapeutic perspective for diverse vascular pathologies.

Abstract

Intercellular communication is a key biological mechanism that is fundamental to maintain tissue homeostasis. Extracellular vesicles (EVs) have emerged as critical regulators of cell–cell communication in both physiological and pathological conditions, due to their ability to shuttle a variety of cell constituents, such as DNA, RNA, lipids, active metabolites, cytosolic, and cell surface proteins. In particular, endothelial cells (ECs) are prominently regulated by EVs released by neighboring cell types. The discovery that cancer cell-derived EVs can control the functions of ECs has prompted the investigation of their roles in tumor angiogenesis and cancer progression. In particular, here, we discuss evidence that supports the roles of exosomes in EC regulation within the tumor microenvironment and in vascular dysfunction leading to atherosclerosis. Moreover, we survey the molecular mechanisms and exosomal cargoes that have been implicated in explanations of these regulatory effects.

Predicted Value of MicroRNAs, Vascular Endothelial Growth Factor, and Intermediate Monocytes in the Left Adverse Ventricular Remodeling in Revascularized ST-Segment Elevation Myocardial Infarction Patients

Background

Primary percutaneous coronary intervention (PPCI) in patients with ST-segment elevation myocardial infarction (STEMI) improves the survival of patients; nevertheless, some patients develop left ventricular adverse remodeling (LVAR) a few months after the intervention. The main objective of this study was to characterize the role of pro-inflammatory cell populations, related cytokines, and microRNAs (miRNAs) released after PPCI as reliable prognostic biomarkers for LVAR in patients with STEMI.

Methods

We evaluated the level of pro-inflammatory subsets, before and after revascularization, 1 and 6 months after PPCI, using flow cytometry. We also performed a miRNA microarray in isolated peripheral blood mononuclear cells (PBMCs) and examined the levels of 27 cytokines in patients’ serum of patients by multiplex ELISA.

Results

We observed that the levels of classical and intermediate monocytes increased 6 h after PPCI in patients who developed LVAR later. Multivariate regression analysis and ROC curves indicated that intermediate monocytes, after PPCI, were the best monocyte subset that correlated with LVAR. Within the 27 evaluated cytokines evaluated, we found that the increase in the level of vascular endothelial growth factor (VEGF) correlated with LVAR. Furthermore, the microarray analysis of PBMCs determined that up to 1,209 miRNAs were differentially expressed 6 h after PPCI in LVAR patients, compared with those who did not develop LVAR. Using RT-qPCR we confirmed a significant increase in miR-16, miR-21-5p, and miR-29a-3p, suggested to modulate the expression of different cytokines, 6 h post-PPCI in LVAR patients. Interestingly, we determined that the combined analysis of the levels of the intermediate monocyte subpopulation, VEGF, and miRNAs gave a better association with LVAR appearance. Similarly, combined ROC analysis provided high accurate specificity and sensibility to identify STEMI patients who will develop LVAR.

Conclusion

Our data suggest that the combined analysis of intermediate monocytes, VEGF, and miRNAs predicts LVAR in STEMI patients.

Construction of an exosome-functionalized graphene oxide based composite bionic smart drug delivery system and its anticancer activity

Graphene oxide has covalently modified by chito oligosaccharides andγ-polyglutamic acid to form GO-CO-γ-PGA, which exhibits excellent performance as a drug delivery carrier, but this carrier did not have the ability to actively target. In this study, the targeting property of breast cancer tumor cell exosomes was exploited to give GO-CO-γ-PGA the ability to target breast tumor cells (MDA-MB-231), and the drug mitoxantrone (MIT) was loaded to finally form EXO-GO-CO-γ-PGA-MIT with an encapsulation efficiency of 73.02%. The pH response of EXO-GO-CO-γ-PGA showed a maximum cumulative release rate of 56.59% (pH 5.0, 120 h) and 6.73% (pH 7.4, 120 h) for MIT at different pH conditions.In vitrocellular assays showed that EXO-GO-CO-γ-PGA-MIT was more potent in killing MDA-MB-231 cells due to its targeting ability and had a significantly higher pro-apoptotic capacity compared to GO-CO-γ-PGA-MIT. The results showed that this bionic nano-intelligent drug delivery system has good drug slow release function and it can increase the local drug concentration of tumor and enhance the pro-apoptotic ability of MIT, so this newly synthesized bionic drug delivery carriers (EXO-GO-CO-γ-PGA-MIT) has potential application in breast cancer treatment.

Mesenchymal Stem Cell-Derived Exosomes as a Novel Strategy for the Treatment of Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) has been reported to be the most prevalent contributor to low back pain, posing a significant strain on the healthcare systems on a global scale. Currently, there are no approved therapies available for the prevention of the progressive degeneration of intervertebral disc (IVD); however, emerging regenerative strategies that aim to restore the normal structure of the disc have been fundamentally promising. In the last decade, mesenchymal stem cells (MSCs) have received a significant deal of interest for the treatment of IVDD due to their differentiation potential, immunoregulatory capabilities, and capability to be cultured and regulated in a favorable environment. Recent investigations show that the pleiotropic impacts of MSCs are regulated by the production of soluble paracrine factors. Exosomes play an important role in regulating such effects. In this review, we have summarized the current treatments for disc degenerative diseases and their limitations and highlighted the therapeutic role and its underlying mechanism of MSC-derived exosomes in IVDD, as well as the possible future developments for exosomes.

Diagnostic and Prognostic Blood Biomarkers in Transient Ischemic Attack and Minor Ischemic Stroke: An Up-To-Date Narrative Review

INTRODUCTION

Early diagnosis and correct risk stratification in patients with transient ischemic attack (TIA) and minor ischemic stroke (MIS) is crucial for the high rate of subsequent disabling stroke. Although highly improved, diagnosis and prognostication of TIA/MIS patients remain still based on clinical and neuroimaging findings, with some inter-rater variability even among trained neurologists.

OBJECTIVES

To provide an up-to-date overview of diagnostic and prognostic blood biomarkers in TIA and MIS patients.

MATERIAL AND METHODS

We performed a bibliographic search on PubMed database with last access on July 10^th 2021. More than 680 articles were screened and we finally included only primary studies on blood biomarkers.

RESULTS

In a narrative fashion, we discussed about blood biomarkers investigated in TIA/MIS patients, including inflammatory, thrombosis, neuronal injury and cardiac analytes, antibodies and microRNAs. Other soluble molecules have been demonstrated to predict the risk of recurrent cerebrovascular events or treatment response in these patients. A rapid point of care assay, combining the determination of different biomarkers, has been developed to improve triage recognition of acute cerebrovascular accidents.

CONCLUSIONS

The implementation of blood biomarkers in the clinical management of TIA/MIS could ameliorate urgent identification, risk stratification and individual treatment choice. Large prospective and longitudinal studies, adopting standardized sampling and analytic procedures, are needed to clarify blood biomarkers kinetic and their relationship with TIA and minor stroke etiology.

In sickness and in health: The functional role of extracellular vesicles in physiology and pathology in vivo: Part II: Pathology: Part II: Pathology

It is clear from Part I of this series that extracellular vesicles (EVs) play a critical role in maintaining the homeostasis of most, if not all, normal physiological systems. However, the majority of our knowledge about EV signalling has come from studying them in disease. Indeed, EVs have consistently been associated with propagating disease pathophysiology. The analysis of EVs in biofluids, obtained in the clinic, has been an essential of the work to improve our understanding of their role in disease. However, to interfere with EV signalling for therapeutic gain, a more fundamental understanding of the mechanisms by which they contribute to pathogenic processes is required. Only by discovering how the EV populations in different biofluids change-size, number, and physicochemical composition-in clinical samples, may we then begin to unravel their functional roles in translational models in vitro and in vivo, which can then feedback to the clinic. In Part II of this review series, the functional role of EVs in pathology and disease will be discussed, with a focus on in vivo evidence and their potential to be used as both biomarkers and points of therapeutic intervention.

Profiling oxylipins released from human platelets activated through the GPVI collagen receptor

In addition to haemostasis, platelets are involved in pathological processes, often driven by material released upon activation. Interaction between collagen and glycoprotein VI (GPVI) is a primary platelet stimulus that liberates arachidonic acid and linoleic acid from membrane phospholipids. These are oxidised by cyclooxygenase-1 (COX-1) and 12-lipoxygenase (12-LOX) to eicosanoids and other oxylipins with various biological properties. Using liquid chromatography-tandem mass spectrometry we found that GPVI-stimulated platelets released significant levels of ten oxylipins; the well documented TxA2 and 12-HETE, PGD₂ and PGE_2, as well as 8-, 9-, 11-, and 15-HETE, 9- and 13-HODE.¹ Levels of oxylipins released from washed platelets mirrored those from platelets stimulated in the presence of plasma, indicating generation from intracellular, rather than exogenous AA/LA. Inhibition of COX-1 with aspirin, as expected, completely abolished production of TxA₂ and PGD/E₂, but also significantly inhibited the release of 11-HETE (89 ± 3%) and 9-HODE (74 ± 6%), and reduced 15-HETE and 13-HODE by ∼33 %. Inhibition of 12-LOX by either esculetin or ML355 inhibited the release of all oxylipins apart from 15-HETE. These findings suggest routes to modify the production of bioactive molecules released by activated platelets.

Diagnostic and Prognostic Significance of serum miR-18a-5p in Patients with Atherosclerosis

Atherosclerosis (AS) is a common vascular disease with great harm. The current study examined the expression pattern of miR-18a-5p in AS patients, and explored its clinical values. 110 AS patients and 68 healthy controls were collected clinically, and the expression pattern of miR-18a-5p in the serum of AS patients was detected using qRT-PCR. All AS patients were followed up for five years to record the adverse cardiovascular events. ROC and Kaplan-Meier (K-M) curve were plotted to assess the diagnostic ability. The multiple Cox regression analysis was performed for independent influencing factors analysis. MiR-18a-5p was at high expression in AS patients, and showed positive correlation with the CIMT value (r = 0.789, P < .001). ROC curve suggested the high diagnostic value of serum miR-18a-5p for AS, with the AUC of 0.894. The diagnostic specificity and sensitivity were 86.8% and 79.1%, respectively. K-M plot demonstrated that cases with high miR-18a-5p levels were more likely to suffer from cardiovascular events, and it is an independent influence factor for the poor clinical outcome. Serum miR-18a-5p serves as a promising biomarker for AS diagnosis, and is related to the occurrence of adverse cardiovascular events.

Exosomes provide unappreciated carrier effects that assist transfers of their miRNAs to targeted cells; I. They are 'The Elephant in the Room'

Extracellular vesicles (EV), such as exosomes, are emerging biologic entities that mediate important newly recognized functional effects. Exosomes are intracellular endosome-originating, cell-secreted, small nano-size EV. They can transfer cargo molecules like miRNAs to act intracellularly in targeted acceptor cells, to then mediate epigenetic functional alterations. Exosomes among EV, are universal nanoparticles of life that are present across all species. Some critics mistakenly hold exosomes to concepts and standards of cells, whereas they are subcellular nanospheres that are a million times smaller, have neither nuclei nor mitochondria, are far less complex and currently cannot be studied deeply and elegantly by many and diverse technologies developed for cells over many years. There are important concerns about the seeming impossibility of biologically significant exosome transfers of very small amounts of miRNAs resulting in altered targeted cell functions. These hesitations are based on current canonical concepts developed for non-physiological application of miRNAs alone, or artificial non-quantitative genetic expression. Not considered is that the natural physiologic intercellular transit via exosomes can contribute numerous augmenting carrier effects to functional miRNA transfers. Some of these are particularly stimulated complex extracellular and intracellular physiologic processes activated in the exosome acceptor cells that can crucially influence the intracellular effects of the transferred miRNAs. These can lead to molecular chemical changes altering DNA expression for mediating functional changes of the targeted cells. Such exosome mediated molecular transfers of epigenetic functional alterations, are the most exciting and life-altering property that these nano EV bring to virtually all of biology and medicine. .Abbreviations: Ab, Antibody Ag Antigen; APC, Antigen presenting cells; CS, contact sensitivity; DC, Dendritic cells; DTH, Delayed-type hypersensitivity; EV, extracellular vesicles; EV, Extracellular vesicle; FLC, Free light chains of antibodies; GI, gastrointestinal; IP, Intraperitoneal administration; IV, intravenous administration; OMV, Outer membrane vesicles released by bacteria; PE, Phos-phatidylethanolamine; PO, oral administration.

Roles of Microvesicles in Tumor Progression and Clinical Applications

Microvesicles are extracellular vesicles with diameter ranging from 100 to 1000 nm that are secreted by tumor cells or other cells in the tumor microenvironment. A growing number of studies demonstrate that tumor-derived microvesicles are involved in tumor initiation and progression, as well as drug resistance. In addition, tumor-derived microvesicles carry a variety of immunogenic molecules and inhibit tumor response to immunotherapy; therefore, they can be exploited for use in tumor vaccines. Moreover, because of their high stability, tumor-derived microvesicles extracted from body fluids can be used as biomarkers for cancer diagnosis or assessment of prognosis. Tumor-derived microvesicles can also be deployed to reverse drug resistance of tumor regenerative cells, or to deliver chemotherapeutic drugs and oncolytic adenovirus for the treatment of cancer patients. This review summarizes the general characteristics of tumor-derived microvesicles, focusing on their biological characteristics, their involvement in tumor progression, and their clinical applications.

Therapeutic effects of mesenchymal stem cells-derived extracellular vesicles' miRNAs on retinal regeneration: a review

Extracellular vesicles (EVs), which consist of microvesicles and exosomes, are secreted from all cells to transform vital information in the form of lipids, proteins, mRNAs and small RNAs such as microRNAs (miRNAs). Many studies demonstrated that EVs' miRNAs have effects on target cells. Numerous people suffer from the blindness caused by retinal degenerations. The death of retinal neurons is irreversible and creates permanent damage to the retina. In the absence of acceptable cures for retinal degenerative diseases, stem cells and their paracrine agents including EVs have become a promising therapeutic approach. Several studies showed that the therapeutic effects of stem cells are due to the miRNAs of their EVs. Considering the effects of microRNAs in retinal cells development and function and studies which provide the possible roles of mesenchymal stem cells-derived EVs miRNA content on retinal diseases, we focused on the similarities between these two groups of miRNAs that could be helpful for promoting new therapeutic techniques for retinal degenerative diseases.

Exosome-eluting stents for vascular healing after ischaemic injury

Drug-eluting stents implanted after ischaemic injury reduce the proliferation of endothelial cells and vascular smooth muscle cells and thus neointimal hyperplasia. However, the eluted drug also slows down the re-endothelialization process, delays arterial healing and can increase the risk of late restenosis. Here we show that stents releasing exosomes derived from mesenchymal stem cells in the presence of reactive oxygen species enhance vascular healing in rats with renal ischaemia-reperfusion injury, promoting endothelial cell tube formation and proliferation, and impairing the migration of smooth muscle cells. Compared with drug-eluting stents and bare-metal stents, the exosome-coated stents accelerated re-endothelialization and decreased in-stent restenosis 28 days after implantation. We also show that exosome-eluting stents implanted in the abdominal aorta of rats with unilateral hindlimb ischaemia regulated macrophage polarization, reduced local vascular and systemic inflammation, and promoted muscle tissue repair.

Functional and Cognitive Decline Is Associated With Increased Endothelial Cell Inflammation and Platelet Activation: Liquid Biopsy of Microvesicles in Community- Dwelling Octogenarians

Increased life expectancy is usually associated with comorbidities, such as cardio and cerebrovascular disease causing impaired functionality. A common underlying cause of these comorbidities is vascular inflammation and injury. Elevated levels of circulating microvesicles (cMV), as a product of a hemostatic and inflammatory cell activation, could be direct mapping of an imbalanced hemostasis. In this manuscript, we aimed to investigate by liquid biopsy whether successful aging can be discriminated by cMV levels and phenotype. To this purpose, we included 135 community-dwelling octogenarians in a cross-sectional study. Successful aging was defined as good functional (Barthel Index > 90 points, and Lawton index score > 7/4 points for women and men, respectively) and cognitive status (Spanish version of the Mini-Mental State Examination -MEC- > 24 points) and no need for institutionalization. Total, annexin V positive (AV⁺), and AV^– cMV from different cell origins from the vascular compartment were phenotypically characterized and quantified from fasting plasma samples by flow cytometry. Successful aging was associated with lower plasma concentrations of total and AV⁺ CD141⁺/CD41⁺-CD61⁺, and PAC1⁺/AV⁺, CD141⁺/AV⁺, and CD36⁺/AV^– cMV. From these phenotypes, ROC curve analyses revealed that CD141⁺/AV⁺ and CD141⁺/CD41⁺-CD61⁺/AV⁺ endothelial- and platelet-derived cMV discriminate successful and non-successful aging with an AUC (95%CI) of 0.655 (0.551, 0.758), P = 0.005, and 0.638 (0.535, 0.741), P = 0.013, respectively. In conclusion, successful aging is associated with low levels of cMV released by endothelial cells and platelets, indicating lower endothelial cell inflammation and platelet activation. Our results contribute to the understanding of the link between unsuccessful aging, cognitive decline and vascular cell inflammatory disturbances.

Circulating miRNAs as Auxiliary Diagnostic Biomarkers for Multiple Myeloma: A Systematic Review, Meta-Analysis, and Recommendations

Multiple myeloma (MM) is a hematologic malignancy characterized by aberrant expansion of monoclonal plasma cells with high mortality and severe complications due to the lack of early diagnosis and timely treatment. Circulating miRNAs have shown potential in the diagnosis of MM with inconsistent results, which remains to be fully assessed. Here we updated a meta-analysis with relative studies and essays published in English before Jan 31, 2021. After steps of screening, 32 studies from 11 articles that included a total of 627 MM patients and 314 healthy controls were collected. All data were analyzed by REVMAN 5.3 and Stata MP 16, and the quality of included literatures was estimated by Diagnostic Accuracy Study 2 (QUADAS-2). The pooled area under the curve (AUC) shown in summary receiver operating characteristic (SROC) analyses of circulating miRNAs was 0.87 (95%CI, 0.81–0.89), and the sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were 0.79, 0.86, 5, 0.27, 22, respectively. Meta-regression and subgroup analysis exhibited that “miRNA cluster”, patient “detailed stage or Ig isotype” accounted for a considerable proportion of heterogeneity, revealing the importance of study design and patient inclusion in diagnostic trials; thus standardized recommendations were proposed for further studies. In addition, the performance of the circulating miRNAs included in MM prognosis and treatment response prediction was summarized, indicating that they could serve as valuable biomarkers, which would expand their clinical application greatly.

The Multifaceted Role of Extracellular Vesicles in Glioblastoma: microRNA Nanocarriers for Disease Progression and Gene Therapy

Glioblastoma (GB) is the most aggressive form of brain cancer in adults, characterized by poor survival rates and lack of effective therapies. MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression post-transcriptionally through specific pairing with target messenger RNAs (mRNAs). Extracellular vesicles (EVs), a heterogeneous group of cell-derived vesicles, transport miRNAs, mRNAs and intracellular proteins, and have been shown to promote horizontal malignancy into adjacent tissue, as well as resistance to conventional therapies. Furthermore, GB-derived EVs have distinct miRNA contents and are able to penetrate the blood-brain barrier. Numerous studies have attempted to identify EV-associated miRNA biomarkers in serum/plasma and cerebrospinal fluid, but their collective findings fail to identify reliable biomarkers that can be applied in clinical settings. However, EVs carrying specific miRNAs or miRNA inhibitors have great potential as therapeutic nanotools in GB, and several studies have investigated this possibility on in vitro and in vivo models. In this review, we discuss the role of EVs and their miRNA content in GB progression and resistance to therapy, with emphasis on their potential as diagnostic, prognostic and disease monitoring biomarkers and as nanocarriers for gene therapy.

MicroRNAs as monitoring markers for right-sided heart failure and congestive hepatopathy

The last decades showed a worrying increase in the evolution of cardiovascular diseases towards different stages of heart failure (HF), as a stigma of the western lifestyle. MicroRNAs (miRNAs), non-coding RNAs, which are approximately 22-nucleotide long, were shown to regulate gene expression at the post-transcriptional level and play a role in the pathogenesis and progression of HF. miRNAs research is of high interest nowadays, as these molecules display mechanisms of action that can influence the course of evolution of common chronic diseases, including HF. The potential of post-transcriptional regulation by miRNAs concerning the diagnosis, management, and therapy for HF represents a new promising approach in the accurate assessment of cardiovascular diseases. This review aims to assess the current knowledge of miRNAs in cardiovascular diseases, especially right-sided heart failure and hepatomegaly. Moreover, attention is focused on their role as potential molecular biomarkers and more promising aspects involving miRNAs as future therapeutic targets in the pathophysiology of HF.

Circulating Extracellular Vesicles Carry Immune Regulatory miRNAs and Regulate Vaccine Efficacy and Local Inflammatory Response After Vaccination

Vaccination is the best prophylaxis for the prevention of infectious diseases, including coronavirus disease 2019. However, the efficacy of vaccines and onset of adverse reactions vary among individuals. Circulating extracellular vesicles (EVs) regulate the immune responses after vaccination by delivering microRNAs (miRNAs) to myeloid and lymphoid cells. Among these, miR-192 levels in serum EVs increase with aging, in an IL-6-dependent manner, reducing excessive IL-6 expression in aged mice, creating a negative feedback loop. Excessive IL-6 expression reduces vaccination efficacy in aged mice, while EV miR-192 improves efficacy in these aged mice as well, making this miRNA an interesting focus of study. miR-21 levels in serum EVs also increase with aging, and regulates the expression of IL-12 required for Th1 responses; therefore, EV miR-21 is expected to regulate vaccine efficacy. miR-451a, another important miRNA, is abundant in serum EVs and controls the expression of cytokines, such as type I interferon and IL-6. However, levels differ among individuals and correlate with local inflammatory symptoms experienced after a seasonal flu vaccination. These findings suggest the importance of EV miRNAs as a tool to improve vaccine efficacy and also as biomarkers to predict the immune response and adverse reactions after vaccinations.

GPC5 suppresses lung cancer progression and metastasis via intracellular CTDSP1/AhR/ARNT signaling axis and extracellular exosome secretion

Lung cancer is the leading cause of cancer-related death worldwide. Glypican-5 (GPC5) is a member of heparan sulfate proteoglycans, and its biological importance in initiation and progression of lung cancer remains controversial. In the present study, we revealed that GPC5 transcriptionally enhanced the expression of CTDSP1 (miR-26b host gene) via AhR-ARNT pathway, and such up-regulation of CTDSP1 intracellularly contributed to the inhibited proliferation of lung cancer cells. Moreover, exosomes derived from GPC5-overexpressing human lung cancer cells (GPC5-OE-derived exosomes) had an extracellular repressive effect on human lymphatic endothelial cells (hLECs), leading to decreased tube formation and migration. Comparison between GPC5-WT- and GPC5-OE-derived exosomes showed that miR-26b (embedded within introns of CTDSP1 gene) was significantly up-regulated in GPC5-OE-derived exosomes and critical to the influence on hLECs. On the mechanism, we demonstrated that miR-26b transferred into hLECs directly targeted to PTK2 3'-UTR and led to PTK2 down-regulation, resulting in defects in tube formation and migration of hLECs. By uncovering the regulation network among GPC5, miR-26b, miR-26b host gene (CTDSP1), and target gene (PTK2), our findings demonstrated that GPC5 functioned as a tumor suppressor in human lung cancer.

Adipose Extracellular Vesicles: Messengers From and to Macrophages in Regulating Immunometabolic Homeostasis or Disorders

Adipose tissue is comprised of heterogenous cell populations that regulate both energy metabolism and immune reactions. Macrophages play critical roles in regulating immunometabolic homeostasis or disorders through cooperation with adipocytes, adipose tissue-derived stem cells (ADSCs) or other cells in adipose tissue. Extracellular vesicles (EVs) are recently recognized as efficient messengers for intercellular communication. Emerging evidences have demonstrated that adipose EVs are actively involved in the mutual interactions of macrophages, adipocytes and ADSCs, which produce considerable influences on immunometabolism under healthy or obese conditions. Here, we will elaborate the production and the characteristics of adipose EVs that are related to macrophages under different metabolic demands or stresses, whilst discuss the roles of these EVs in regulating local or systemic immunometabolic homeostasis or disorders in the context of adipocyte-macrophage dialogue and ADSC-macrophage interaction. Particularly, we provide a profile of dynamic adipose microenvironments based on macrophages. Adipose EVs act as the messengers between ADSCs and macrophages to maintain the balance of metabolism and immunity, while drive a vicious cycle between hypertrophic adipocytes and inflammatory macrophages to cause immunometabolic imbalance. This review may provide valuable information about the physio- or pathological roles of adipose EVs and the application of adipose EVs in the diagnosis and treatment of metabolic diseases.

Emerging role of exosomes in arterial and renal calcification

Exosomes are small, cell-derived vesicles of 30-100 nm that participate in cell-to-cell communication. They are released by many cells, such as dendritic cells (DC), lymphocytes, platelets, epithelial cells, endothelial cells (EC), and are found in most body fluids, including blood, saliva, urine, and breast milk. The exosomes released from cells within the cardiovascular system may contain either inhibitors of calcification in normal physiological conditions or promoters in the pathological environment [atherosclerosis (AS), and Chronic Kidney Disease (CKD)]. The exosomes of the vascular smooth muscle cells (VSMCs) are novel players in vascular repair processes and calcification. Several studies have shown that the cytoplasmic contents of exosomes are rich in a variety of proteins, nucleic acids, and lipids. Currently, exosomal micro RNAs and proteins are increasingly being recognized as biomarkers for the diagnosis of several diseases, including those of kidney and liver, as well as different types of cancer. In this review, we summarize recent advances in the role of exosomes in vascular calcification and their potential applications as diagnostic markers as well as a brief overview of the role of stem cell-derived exosomes in cardiovascular diseases.

miR-106a-363 cluster in extracellular vesicles promotes endogenous myocardial repair via Notch3 pathway in ischemic heart injury

Endogenous capability of the post-mitotic human heart holds great promise to restore the injured myocardium. Recent evidence indicates that the extracellular vesicles (EVs) regulate cardiac homeostasis and regeneration. Here, we investigated the molecular mechanism of EVs for self-repair. We isolated EVs from human iPSC-derived cardiomyocytes (iCMs), which were exposed to hypoxic (hEVs) and normoxic conditions (nEVs), and examined their roles in in vitro and in vivo models of cardiac injury. hEV treatment significantly improved the viability of hypoxic iCMs in vitro and cardiac function of severely injured murine myocardium in vivo. Microarray analysis of the EVs revealed significantly enriched expression of the miR-106a-363 cluster (miR cluster) in hEVs vs. nEVs. This miR cluster preserved survival and contractility of hypoxia-injured iCMs and maintained murine left-ventricular (LV) chamber size, improved LV ejection fraction, and reduced myocardial fibrosis of the injured myocardium. RNA-Seq analysis identified Jag1-Notch3-Hes1 as a target intracellular pathway of the miR cluster. Moreover, the study found that the cell cycle activator and cytokinesis genes were significantly up-regulated in the iCMs treated with miR cluster and Notch3 siRNA. Together, these results suggested that the miR cluster in the EVs stimulated cardiomyocyte cell cycle re-entry by repressing Notch3 to induce cell proliferation and augment myocardial self-repair. The miR cluster may represent an effective therapeutic approach for ischemic cardiomyopathy.

Functional repertoire of EV-associated miRNA profiles after lipoprotein depletion via ultracentrifugation and size exclusion chromatography from autologous blood products

Cartilage breakdown, inflammation and pain are hallmark symptoms of osteoarthritis, and autologous blood products such as citrate-anticoagulated platelet-rich plasma (CPRP) or hyperacute serum (hypACT) have been developed as a regenerative approach to rebuild cartilage, inhibit inflammation and reduce pain. However, mechanisms of action of these blood derivatives are still not fully understood, in part due to the large number of components present in these medical products. In addition, the discovery of extracellular vesicles (EVs) and their involvement in intercellular communication mediated by cargo molecules like microRNAs (miRNAs) opened up a whole new level of complexity in understanding blood products. In this study we focused on the development of an isolation protocol for EVs from CPRP and hypACT that can also deplete lipoproteins, which are often co-isolated in EV research due to shared physical properties. Several isolation methods were compared in terms of particle yield from CPRP and hypACT. To gain insights into the functional repertoire conveyed via EV-associated miRNAs, we performed functional enrichment analysis and identified NFκB signaling strongly targeted by CPRP EV miRNAs, whereas hypACT EV miRNAs affect IL6- and TGFβ/SMAD signaling.

Global REACH 2018: dysfunctional extracellular microvesicles in Andean highlander males with excessive erythrocytosis

High altitude-related excessive erythrocytosis (EE) is associated with increased cardiovascular risk. The experimental aim of this study was to determine the effects of microvesicles isolated from Andean highlanders with EE on endothelial cell inflammation, oxidative stress, apoptosis, and nitric oxide (NO) production. Twenty-six male residents of Cerro de Pasco, Peru (4,340 m), were studied: 12 highlanders without EE (age: 40 ± 4 yr; BMI: 26.4 ± 1.7; Hb: 17.4 ± 0.5 g/dL, Spo₂: 86.9 ± 1.0%) and 14 highlanders with EE (43 ± 4 yr; 26.2 ± 0.9; 24.4 ± 0.4 g/dL; 79.7 ± 1.6%). Microvesicles were isolated, enumerated, and collected from plasma by flow cytometry. Human umbilical vein endothelial cells were cultured and treated with microvesicles from highlanders without and with EE. Microvesicles from highlanders with EE induced significantly higher release of interleukin (IL)-6 (89.8 ± 2.7 vs. 77.1 ± 1.9 pg/mL) and IL-8 (62.0 ± 2.7 vs. 53.3 ± 2.2 pg/mL) compared with microvesicles from healthy highlanders. Although intracellular expression of total NF-κB p65 (65.3 ± 6.0 vs. 74.9 ± 7.8.9 AU) was not significantly affected in cells treated with microvesicles from highlanders without versus with EE, microvesicles from highlanders with EE resulted in an ∼25% higher (P < 0.05) expression of p-NF-κB p65 (173.6 ± 14.3 vs. 132.8 ± 12.2 AU). Cell reactive oxygen species production was significantly higher (76.4.7 ± 5.4 vs. 56.7 ± 1.7% of control) and endothelial nitric oxide synthase (p-eNOS) activation (231.3 ± 15.5 vs. 286.6 ± 23.0 AU) and NO production (8.3 ± 0.6 vs. 10.7 ± 0.7 μM/L) were significantly lower in cells treated with microvesicles from highlanders with versus without EE. Cell apoptotic susceptibility was not significantly affected by EE-related microvesicles. Circulating microvesicles from Andean highlanders with EE increased endothelial cell inflammation and oxidative stress and reduced NO production.NEW & NOTEWORTHY In this study, we determined the effects of microvesicles isolated from Andean highlanders with excessive erythrocytosis (EE) on endothelial cell inflammation, oxidative stress, apoptosis, and NO production. Microvesicles from highlanders with EE induced a dysfunctional response from endothelial cells characterized by increased cytokine release and expression of active nuclear factor-κB and reduced nitric oxide production. Andean highlanders with EE exhibit dysfunctional circulating extracellular microvesicles that induce a proinflammatory, proatherogenic endothelial phenotype.

Disturbed Blood Flow Acutely Increases Endothelial Microparticles and Decreases Flow Mediated Dilation in Patients With Heart Failure With Reduced Ejection Fraction

Introduction

Disturbed blood flow, characterized by high retrograde and oscillatory shear rate (SR), is associated with a proatherogenic phenotype. The impact of disturbed blood flow in patients with heart failure with reduced ejection fraction (HFrEF) remains unknown. We tested the hypothesis that acute elevation to retrograde and oscillatory SR provoked by local circulatory occlusion would increase endothelial microparticles (EMPs) and decrease brachial artery flow-mediated dilation (FMD) in patients with HFrEF.

Methods

Eighteen patients with HFrEF aged 55 ± 2 years, with left ventricular ejection fraction (LVEF) 26 ± 1%, and 14 control subjects aged 49 ± 2 years with LVEF 65 ± 1 randomly underwent experimental and control sessions. Brachial artery FMD (Doppler) was evaluated before and after 30 min of disturbed forearm blood flow provoked by pneumatic cuff (Hokanson) inflation to 75 mm Hg. Venous blood samples were collected at rest, after 15 and 30 min of disturbed blood flow to assess circulating EMP levels (CD42b−/CD31+; flow cytometry).

Results

At rest, FMD was lower in patients with HFrEF compared with control subjects (P < 0.001), but blood flow patterns and EMPs had no differences (P > 0.05). The cuff inflation provoked a greater retrograde SR both groups (P < 0.0001). EMPs responses to disturbed blood flow significantly increased in patients with HFrEF (P = 0.03). No changes in EMPs were found in control subjects (P > 0.05). Disturbed blood flow decreased FMD both groups. No changes occurred in control condition.

Conclusion

Collectively, our findings suggest that disturbed blood flow acutely decreases FMD and increases EMP levels in patients with HFrEF, which may indicate that this set of patients are vulnerable to blood flow disturbances.

Circulating extracellular vesicles from patients with acute chest syndrome disrupt adherens junctions between endothelial cells

BACKGROUND

Small cell-derived extracellular vesicles (EVs) can affect endothelial function. We previously found that patients with sickle cell disease (SCD) have greater numbers of circulating EVs than subjects without the disease, and the EVs differentially disrupt endothelial integrity in vitro. Because endothelial disruption is a critical component of acute chest syndrome (ACS), we hypothesized that EVs isolated during ACS would induce greater endothelial damage than those isolated at baseline.

METHODS

Nine pediatric subjects had plasma isolated at baseline and during ACS from which EVs were isolated. Cultured microvascular endothelial cells were treated with EVs and then studied by immunofluorescence microscopy to localize VE-cadherin and F-actin.

RESULTS

The EVs had a diameter of 95 nm. They contained CD63 and flotillin-1, which were increased in SCD patients (5-13-fold compared to control) and further increased between baseline and ACS (24-57%). The EVs contained hemoglobin, glycophorin A, and ferritin. Treatment with baseline EVs caused modest separation of endothelial cells, while ACS EVs caused substantial disruptions of the endothelial cell monolayers. EVs from subjects with ACS also caused a 50% decrease in protein levels of VE-cadherin.

CONCLUSIONS

These results suggest that circulating EVs can modulate endothelial integrity contributing to the development of ACS in SCD patients by altering cadherin-containing intercellular junctions.

IMPACT

Sickle cell disease patients have circulating extracellular vesicles (EVs) that modulate endothelial integrity by altering cadherin-containing intercellular junctions. Disruption is more severe by EVs obtained during acute chest syndrome (ACS). These results expand our knowledge of the pathophysiology of acute chest syndrome and the vasculopathies of sickle cell disease.