Endothelium-derived Extracellular Vesicles Research Articles

Endothelium-Derived Extracellular Vesicles Expressing Intercellular Adhesion Molecules Reflect Endothelial Permeability and Sepsis Severity.

Currently, clinical indicators for evaluating endothelial permeability in sepsis are unavailable. Endothelium-derived extracellular vesicles (EDEVs) are emerging as biomarkers of endothelial injury. Platelet endothelial cell adhesion molecule (PECAM) and vascular endothelial (VE)-cadherin are constitutively expressed endothelial intercellular adhesion molecules that regulate intercellular adhesion and permeability. Herein, we investigated the possible association between EDEVs expressing intercellular adhesion molecules (PECAM+ or VE-cadherin+ EDEVs) and endothelial permeability and sepsis severity. Human umbilical vein endothelial cells (HUVECs) were stimulated with tumor necrosis factor alpha (TNF-α) directly or after pretreatment with permeability-modifying reagents such as angiopoietin-1, prostacyclin, or vascular endothelial growth factor (VEGF) to alter TNF-α-induced endothelial hyperpermeability. Endothelial permeability was measured using the dextran assay or transendothelial electrical resistance. Additionally, a prospective cross-sectional observational study was conducted to analyze circulating EDEV levels in patients with sepsis. EDEVs were examined in HUVEC culture supernatants or patient plasma (nonsepsis, n = 30; sepsis, n = 30; septic shock, n = 42) using flow cytometry. The Wilcoxon rank-sum test was used for comparisons between 2 groups. Comparisons among 3 or more groups were performed using the Steel-Dwass test. Spearman's test was used for correlation analysis. Statistical significance was set at P < .05. TNF-α stimulation of HUVECs significantly increased EDEV release and endothelial permeability. Pretreatment with angiopoietin-1 or prostacyclin suppressed the TNF-α-induced increase in endothelial permeability and inhibited the release of PECAM+ and VE-cadherin+ EDEVs. In contrast, pretreatment with VEGF increased TNF-α-induced endothelial permeability and the release of PECAM+ and VE-cadherin+ EDEVs. However, pretreatment with permeability-modifying reagents did not affect the release of EDEVs expressing inflammatory stimulus-inducible endothelial adhesion molecules such as E-selectin, intracellular adhesion molecule-1, or vascular cell adhesion molecule-1. The number of PECAM+ EDEVs on admission in the septic-shock group (232 [124, 590]/μL) was significantly higher (P = .043) than that in the sepsis group (138 [77,267]/μL), with an average treatment effect of 98/μL (95% confidence interval [CI], 2-270/μL), and the number of VE-cadherin+ EDEVs in the septic-shock group (173 [76,339]/μL) was also significantly higher (P = .004) than that in the sepsis group (81 [42,159]/μL), with an average treatment effect (ATE) of 79/μL (95% CI, 19-171/μL); these EDEV levels remained elevated until day 5. EDEVs expressing intercellular adhesion molecules (PECAM+ or VE-cadherin+ EDEVs) may reflect increased endothelial permeability and could be valuable diagnostic and prognostic markers for sepsis.

Xenorecognition and costimulation of porcine endothelium-derived extracellular vesicles in initiating human porcine-specific T cell immune responses

Porcine vascular endothelial cells (PECs) form a mechanistic centerpiece of xenograft rejection. Here, we determined that resting PECs release swine leukocyte antigen class I (SLA-I) but not swine leukocyte antigen class-II DR (SLA-DR) expressing extracellular vesicles (EVs) and investigated whether these EVs proficiently initiate xenoreactive T cell responses via direct xenorecognition and costimulation. Human T cells acquired SLA-I+ EVs with or without direct contact to PECs, and these EVs colocalized with T cell receptors. Although interferon gamma-activated PECs released SLA-DR+ EVs, the binding of SLA-DR+ EVs to T cells was sparse. Human T cells demonstrated low levels of proliferation without direct contact to PECs, but marked T cell proliferation was induced following exposure to EVs. EV-induced proliferation proceeded independent of monocytes/macrophages, suggesting that EVs delivered both a T cell receptor signal and costimulation. Costimulation blockade targeting B7, CD40L, or CD11a significantly reduced T cell proliferation to PEC-derived EVs. These findings indicate that endothelial-derived EVs can directly initiate T cell-mediated immune responses, and suggest that inhibiting the release of SLA-I EVs from organ xenografts has the potential to modify the xenograft rejection. We propose a secondary-direct pathway for T cell activation via xenoantigen recognition/costimulation by endothelial-derived EVs.

Circulating galectin-3 promotes tumor-endothelium-adhesion by upregulating ICAM-1 in endothelium-derived extracellular vesicles.

The adhesion of tumor cells to vascular endothelial cells is an important process of tumor metastasis. Studies have shown that tumor could educate vascular endothelial cells to promote tumor metastasis through many ways. However, the effect of tumor cells on the functions of vascular endothelial cells-derived extracellular vesicles (H-EVs) and the mechanisms underlying their effects in tumor-endothelium adhesion in metastasis remain mysterious. In this study, we found that H-EVs promoted the adhesion of triple negative breast cancer cell to endothelial cells and cirGal-3 enhanced the adhesion-promoting effects of H-EVs. The underlying mechanism was related to the upregulation of glycolysis in endothelial cells induced by cirGal-3 which led to the increase of the ICAM-1 expression and its transmission to MDA-MB-231 cells by H-EVs. Targeting of cirGal-3 or glycolysis of vascular endothelium in breast cancer therefore represents a promising therapeutic strategy to reduce metastasis.

Brain endothelium-derived extracellular vesicles containing amyloid-beta induce mitochondrial alterations in neural progenitor cells.

Elevated brain deposits of amyloid beta (Aβ40) contribute to neuropathology and cognitive dysfunction in Alzheimer's disease (AD). However, the role of the blood-brain barrier (BBB) as an interface for the transfer of Aβ40 from the periphery into the brain is not well characterized. In addition, a substantial population of neural progenitor cells (NPCs) resides in close proximity to brain capillaries that form the BBB. The aim of this study is to understand the impact of brain endothelium-derived extracellular vesicles (EV) containing Aβ40 on metabolic functions and differentiation of NPCs. Endothelial EVs were derived from an in vitro model of the brain endothelium treated with 100 nM Aβ40 or PBS. We then analyzed the impact of these EVs on mitochondrial morphology and bioenergetic disruption of NPCs. In addition, NPCs were differentiated and neurite development upon exposure to EVs was assessed using the IncuCyte Zoom live cell imaging system. We demonstrate that physiological concentrations of Aβ40 can be transferred to accumulate in NPCs via endothelial EVs. This transfer results in mitochondrial dysfunction, disrupting crista morphology, metabolic rates, fusion and fission dynamics of NPCs, as well as their neurite development. Intercellular transfer of Aβ40 is carried out by brain endothelium-derived EVs, which can affect NPC differentiation and induce mitochondrial dysfunction, leading to aberrant neurogenesis. This has pathological implications because NPCs growing into neurons are incorporated into cerebral structures involved in learning and memory, two common phenotypes affected in AD and related dementias.

Endothelial Extracellular Vesicles: From Keepers of Health to Messengers of Disease.

Endothelium has a rich vesicular network that allows the exchange of macromolecules between blood and parenchymal cells. This feature of endothelial cells, along with their polarized secretory machinery, makes them the second major contributor, after platelets, to the particulate secretome in circulation. Extracellular vesicles (EVs) produced by the endothelial cells mirror the remarkable molecular heterogeneity of their parent cells. Cargo molecules carried by EVs were shown to contribute to the physiological functions of endothelium and may support the plasticity and adaptation of endothelial cells in a paracrine manner. Endothelium-derived vesicles can also contribute to the pathogenesis of cardiovascular disease or can serve as prognostic or diagnostic biomarkers. Finally, endothelium-derived EVs can be used as therapeutic tools to target endothelium for drug delivery or target stromal cells via the endothelial cells. In this review we revisit the recent evidence on the heterogeneity and plasticity of endothelial cells and their EVs. We discuss the role of endothelial EVs in the maintenance of vascular homeostasis along with their contributions to endothelial adaptation and dysfunction. Finally, we evaluate the potential of endothelial EVs as disease biomarkers and their leverage as therapeutic tools.

Abstract 6487: Circulating tumor cells, tumor- and endothelium- derived extracellular vesicles, but not circulating endothelial cells associate with poor prognosis in colorectal cancer

Abstract Elevated tumor-derived EV (tdEV) and Circulating Tumor Cell (CTC) load in patients with metastatic cancer is associated with poor clinical outcome. In this study, we investigated whether endothelium-derived extracellular vesicles (edEVs) can be detected in the blood of metastatic colorectal cancer (mCRC) patients and whether there is an association with prognosis. The open-source ACCEPT software was used to enumerate edEVs, tdEVs and other objects from digitally stored CellSearch® images obtained after Circulating Endothelial Cell (CEC) and CTC enrichment from blood of 395 mCRC patients, before the initiation of a new therapy. Patients had participated in the prospective phase III CAIRO2 study. ACCEPT classified objects, CTC and CEC counts and patient information were used in univariable and multivariable analysis to determine their relation with Progression-Free Survival (PFS) and Overall Survival (OS). edEVs are present in blood of mCRC patients at 5-10 fold higher frequencies than CECs. A significantly shorter PFS and OS was observed for patients with ≥ 3 CTCs/ 7.5 mL, ≥ 40 tdEVs/ 7.5 mL and ≥ 287 edEVs/ 4.0 mL. The Hazard Ratio HR (95% CI) of PFS for increased CTCs, tdEVs and edEVs was 1.4 (1.1-1.9), 2.0 (1.5-2.6) and 1.7 (1.2-2.5), respectively. Similarly, the HR of OS for increased CTCs, tdEVs and edEVs was 2.2 (1.7-3.0), 2.7 (2.0-3.5) and 2.1 (1.5-2.8), respectively. There was no cut-off value for CECs leading to a dichotomization of patients with a significant HR. Both tdEVs and edEVs remained significant predictors of OS in multivariable analysis. edEVs and tdEVs are independent prognostic factors for OS in mCRC patients. Funded by the NWO Applied and Engineering Sciences Cancer-ID project #14190. Citation Format: Afroditi Nanou, Linda Mol, Miriam Koopman, Cornelis J. Punt, Leon W. Terstappen. Circulating tumor cells, tumor- and endothelium- derived extracellular vesicles, but not circulating endothelial cells associate with poor prognosis in colorectal cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6487.

Raman spectral signatures of urinary extracellular vesicles from diabetic patients and hyperglycemic endothelial cells as potential biomarkers in diabetes

Raman spectroscopy was applied to the measurement of urinary and in vitro endothelium-derived extracellular vesicles (EVs) isolated by hydrostatic filtration dialysis (HFD) method. Raman spectra obtained for urinary EVs (UEVs) showed distinct differences in the fingerprint region. In contrast, average Raman spectra of endothelium-derived EVs samples were almost identical. Cluster Analysis of UEVs significantly discriminated diabetic samples from control, moreover endothelium-derived EVs revealed stronger similarity between long hyperglycemia and normoglycemia samples compared to short hyperglycemia. Results obtained from Partial Least Squares analysis corresponded well with integral intensities of selected bands. Our proof-of-concept approach demonstrates the potential for Raman spectroscopy to be used both for identification of EVs molecular signatures in urine samples from patients with type 2 diabetes mellitus and good glycemic control and unsatisfactory glycemic control as well as for in vitro hyperglycemic model. This noninvasive technique may be useful in identifying new biomarkers of diabetes and renal complications.

Endothelial-driven increase in plasma thrombin generation characterising a new hypercoagulable phenotype in acute heart failure

BackgroundSubjects with heart failure (HF) are at higher risk of developing thrombosis. We investigated whether endothelium activation and inflammation induce a prothrombotic biological profile in patients with acute decompensated HF (ADHF) and sinus rhythm. MethodsOur prospective study included 34 ADHF patients, 30 patients with stable chronic HF (CHF) and 30 control inpatients without HF. In vitro thrombin generation and its downregulation by activated protein C (APC) was monitored by calibrated automated thrombography at hospital admission, at the day of discharge and after discharge, following at least six weeks of clinical stability. Circulating endothelium-derived extracellular vesicles (eEVs) were quantified by flow cytometry and nucleosomes by ELISA. ResultsThrombin generation is increased and APC sensitivity is decreased independently of platelets in ADHF at admission compared to controls (p < 0.01). Thrombin generation was also increased in CHF but only in the presence of platelets. Plasma markers of endothelium activation (von Willebrand factor, factor VIII, procoagulant eEVs and circulating nucleosomes) and the ability of plasmas to induce neutrophil extracellular trap formation in control neutrophils are elevated in ADHF at admission compared to controls (p < 0.001). In-hospital prothrombotic changes in ADHF improved significantly at the post-discharge time-point. Circulating nucleosomes were positively correlated with APC sensitivity (p = 0.013) and annexin-V-positive eEVs (p = 0.004). ConclusionsThis proof-of-concept study identified an endothelial-driven hypercoagulable phenotype at the acute phase of decompensated HF contrasting with the platelet-dependent prothrombotic state in CHF. These results highlighted a cross-talk between circulating eEVs and nucleosomes, procoagulant factors and impairment of the APC anticoagulant activity in ADHF.

Endothelium-derived extracellular vesicles promote splenic monocyte mobilization in myocardial infarction.

Transcriptionally activated monocytes are recruited to the heart after acute myocardial infarction (AMI). After AMI in mice and humans, the number of extracellular vesicles (EVs) increased acutely. In humans, EV number correlated closely with the extent of myocardial injury. We hypothesized that EVs mediate splenic monocyte mobilization and program transcription following AMI. Some plasma EVs bear endothelial cell (EC) integrins, and both proinflammatory stimulation of ECs and AMI significantly increased VCAM-1–positive EV release. Injected EC-EVs localized to the spleen and interacted with, and mobilized, splenic monocytes in otherwise naive, healthy animals. Analysis of human plasma EV-associated miRNA showed 12 markedly enriched miRNAs after AMI; functional enrichment analyses identified 1,869 putative mRNA targets, which regulate relevant cellular functions (e.g., proliferation and cell movement). Furthermore, gene ontology termed positive chemotaxis as the most enriched pathway for the miRNA-mRNA targets. Among the identified EV miRNAs, EC-associated miRNA-126-3p and -5p were highly regulated after AMI. miRNA-126-3p and -5p regulate cell adhesion– and chemotaxis-associated genes, including the negative regulator of cell motility, plexin-B2. EC-EV exposure significantly downregulated plexin-B2 mRNA in monocytes and upregulated motility integrin ITGB2. These findings identify EVs as a possible novel signaling pathway by linking ischemic myocardium with monocyte mobilization and transcriptional activation following AMI.

Mitochondria-regulated formation of endothelium-derived extracellular vesicles shifts the mediator of flow-induced vasodilation.

To examine the effect of endothelium-derived extracellular vesicles (eEVs) on the mediator of flow-induced dilation (FID), composition, formation, and functional effects on the mediator of FID were examined from two different eEV subtypes, one produced from ceramide, while the other was produced from plasminogen-activator inhibitor 1 (PAI-1). Using video microscopy, we measured internal-diameter changes in response to increases in flow in human adipose resistance arteries acutely exposed (30 min) to eEVs derived from cultured endothelial cells exposed to ceramide or PAI-1. FID was significantly impaired following exposure to 500K/ml (K = 1,000) of ceramide-induced eEVs (Cer-eEVs) but unaffected by 250K/ml. FID was reduced in the presence of PEG-catalase following administration of 250K/ml of Cer-eEVs and PAI-1 eEVs, whereas Nω-nitro-l-arginine methyl ester (l-NAME) had no effect. Pathway analysis following protein composition examination using liquid chromatography tandem mass spectrometry (LC-MS/MS) demonstrated that both subtypes were strongly linked to similar biological functions, primarily, mitochondrial dysfunction. Flow cytometry was used to quantify eEVs in the presence or absence of l-phenylalanine-4'-boronic acid (PBA) and mitochondria-targeted [93-boronophenyl)methyl]triphenyl-phosphonium (mito-PBA), cytosolic and mitochondrial-targeted antioxidants, respectively. eEV formation was significantly and dramatically reduced with mito-PBA treatment. In conclusion, eEVs have a biphasic effect, with higher doses impairing and lower doses shifting the mediator of FID from nitric oxide (NO) to hydrogen peroxide (H2O2). Despite differences in protein content, eEVs may alter vascular function in similar directions, regardless of the stimulus used for their formation. Furthermore, mitochondrial ROS production is required for the generation of these vesicles.NEW & NOTEWORTHY The vascular effect of endothelium-derived extracellular vesicles (eEVs) is biphasic, with higher doses decreasing the magnitude of flow-induced dilation (FID) compared with lower doses that shift the mediator of FID from nitric oxide to H2O2 eEVs may cause vascular dysfunction via similar pathways despite being formed from different stimuli, although both require mitochondrial reactive oxygen species for their formation.

ENDOTHELIAL CELLS REPROGRAM MONOCYTE RESPONSES THROUGH TRANSFER OF ANTI-INFLAMMATORY MICRORNAS

High concentrations of circulating extracellular vesicles (EVs) are present in the blood, and their levels and contents are altered in several disease states, including cardiovascular disease. However, the function of circulating EVs − especially the microRNAs that they contain − are poorly understood. We sought to determine the effect of secreted vesicles produced by quiescent endothelial cells (ECs) on monocyte inflammatory responses, and to assess whether transfer of microRNAs occurs between these cells. We observed that monocytes co-cultured (but not in contact) with ECs were refractory to inflammatory activation. Further characterization revealed that endothelium-derived extracellular vesicles (EC-EVs) could suppress monocyte activation, suggesting that ECs secrete anti-inflammatory vesicles that affect monocyte phenotype. Monocytes treated with EC-EVs displayed enhanced immunomodulatory responses and diminished pro-inflammatory responses. EVs isolated from mouse circulation also suppressed monocyte activation. Importantly, injection of EC-EVs in vivo repressed monocyte/macrophage activation in response to lipopolysaccharide treatment, confirming our in vitro findings. We found that several microRNAs were elevated in EC-EV-treated monocytes. In particular, miR-10a was transferred to monocytes from EC-EVs and could repress inflammatory signaling through the targeting of several components of the NF-κB pathway, including IRAK4. ECs secrete anti-inflammatory microRNA-containing vesicles that can modulate monocyte activation. Our findings suggest that altered EV secretion and/or microRNA content may affect vascular inflammation in the setting of cardiovascular disease.

Endothelial cells suppress monocyte activation through secretion of extracellular vesicles containing antiinflammatory microRNAs

AbstractThe blood contains high concentrations of circulating extracellular vesicles (EVs), and their levels and contents are altered in several disease states, including cardiovascular disease. However, the function of circulating EVs, especially the microRNAs (miRNAs) that they contain, are poorly understood. We sought to determine the effect of secreted vesicles produced by quiescent endothelial cells (ECs) on monocyte inflammatory responses and to assess whether transfer of microRNAs occurs between these cells. We observed that monocytic cells cocultured (but not in contact) with ECs were refractory to inflammatory activation. Further characterization revealed that endothelium-derived EVs (EC-EVs) suppressed monocyte activation by enhancing immunomodulatory responses and diminishing proinflammatory responses. EVs isolated from mouse plasma also suppressed monocyte activation. Importantly, injection of EC-EVs in vivo repressed monocyte/macrophage activation, confirming our in vitro findings. We found that several antiinflammatory microRNAs were elevated in EC-EV–treated monocytes. In particular, miR-10a was transferred to monocytic cells from EC-EVs and could repress inflammatory signaling through the targeting of several components of the NF-κB pathway, including IRAK4. Our findings reveal that ECs secrete EVs that can modulate monocyte activation and suggest that altered EV secretion and/or microRNA content may affect vascular inflammation in the setting of cardiovascular disease.

Induction of pulmonary hypertensive changes by extracellular vesicles from monocrotaline-treated mice

Circulating endothelium-derived extracellular vesicles (EV) levels are altered in pulmonary arterial hypertension (PAH) but whether they are biomarkers of cellular injury or participants in disease pathogenesis is unknown. Previously, we found that lung-derived EVs (LEVs) induce bone marrow-derived progenitor cells to express lung-specific mRNA and protein. In this study, we sought to determine whether LEV or plasma-derived EV (PEV) alter pulmonary vascular endothelial or marrow progenitor cell phenotype to induce pulmonary vascular remodelling. LEV, PEV isolated from monocrotaline (MCT-EV)- or vehicle-treated mice (vehicle-EV) were injected into healthy mice. Right ventricular (RV) hypertrophy and pulmonary vascular remodelling were assessed by RV-to-body weight (RV/BW) and blood vessel wall thickness-to-diameter (WT/D) ratios. RV/BW, WT/D ratios were elevated in MCT- vs. vehicle-injected mice (1.99 ± 0.09 vs. 1.04 ± 0.09 mg/g; 0.159 ± 0.002 vs. 0.062 ± 0.009%). RV/BW, WT/D ratios were higher in mice injected with MCT-EV vs. mice injected with vehicle-EV (1.63 ± 0.09 vs. 1.08 ± 0.09 mg/g; 0.113 ± 0.02 vs. 0.056 ± 0.01%). Lineage-depleted bone marrow cells incubated with MCT-EV and marrow cells isolated from mice infused with MCT-EV had greater expression of endothelial progenitor cell mRNAs and mRNAs abnormally expressed in PAH than cells incubated with vehicle-EV or isolated from vehicle-EV infused mice. MCT-EV induced an apoptosis-resistant phenotype in murine pulmonary endothelial cells and lineage-depleted bone marrow cells incubated with MCT-EV induced pulmonary hypertension when injected into healthy mice. EV from MCT-injured mice contribute to the development of MCT-induced pulmonary hypertension. This effect may be mediated directly by EV on the pulmonary vasculature or by differentiation of bone marrow cells to endothelial progenitor cells that induce pulmonary vascular remodelling.