Cellular microparticles: a disseminated storage pool of bioactive vascular effectors

Circulating biosignatures in multiple myeloma and their role in multidrug resistance

A major obstacle to chemotherapeutic success in cancer treatment is the development of drug resistance. This occurs when a tumour fails to reduce in size after treatment or when there is clinical relapse after an initial positive response to treatment. A unique and serious type of resistance is multidrug resistance (MDR). MDR causes the simultaneous cross resistance to unrelated drugs used in chemotherapy. MDR can be acquired through genetic alterations following drug exposure, or as discovered by us, through alternative pathways mediated by the transfer of functional MDR proteins and nucleic acids by extracellular vesicles (M Bebawy V Combes E Lee R Jaiswal J Gong A Bonhoure GE Grau, 23 9 1643 1649, 2009).Multiple myeloma is an incurable cancer of bone marrow plasma cells. Treatment involves high dose combination chemotherapy and patient response is unpredictable and variable due to the presence of multisite clonal tumour infiltrates. This clonal heterogeneity can contribute to the development of MDR. There is currently no approved clinical test for the minimally invasive testing of MDR in myeloma.Extracellular vesicles comprise a group of heterogeneous cell-derived membranous structures which include; exosomes, microparticles (microvesicles), migrasomes and apoptotic bodies. Extracellular vesicles serve an important role in cellular communication through the intercellular transfer of cellular protein, nucleic acid and lipid cargo. Of these, microparticles (MPs) originate from the cell plasma membrane and vary in size from 0.1-1um. We have previously shown that MPs confer MDR through the transfer of resistance proteins and nucleic acids. A test for the early detection of MDR would benefit clinical decision making, improve survival and support rational drug use. This review focuses on microparticles as novel clinical biomarkers for the detection of MDR in Myeloma and discusses their role in the therapeutic management of the disease.

Elevated Levels of Procoagulant Microvesicles and Tissue-Factor Bearing Microvesicles in Malaria Patients

Background

Procoagulant microvesicles (MVs) are submicron membrane fragments released from activated cells and cells undergoing apoptosis. The procoagulant activity of MVs is enhanced in the presence of tissue factor (TF). MVs and TF are active mediators that induce pro-inflammatory response and prothrombotic tendency and have been linked to the severity of several disorders, including malaria infection. The current study aimed to measure the levels of circulating procoagulant MVs and TF-bearing MVs in malaria patients and correlate these levels with other hematological parameters and parasitemia.

Materials and Methods

Levels of MVs and TF-bearing MVs in the plasma of children and adult patients infected with Plasmodium falciparum were measured alongside matched healthy controls.

Results

Patients with Plasmodium falciparum infection had ~3.8 times MVs (p < 0.0001) and ~13.0 times TF-bearing MVs compared to the matched healthy controls. MVs showed inverse significant correlation with platelet count (p = 0.0055), hemoglobin (p = 0.0004) and parasitemia.

Conclusion

Elevated levels of MVs and TF-bearing MVs could be useful biomarkers to evaluate the procoagulant activity, inflammatory response and parasitemia levels in malaria infection, aiding in better management of the disease.

Grafted dinuclear zinc complexes for selective recognition of phosphatidylserine: Application to the capture of extracellular membrane microvesicles

Microvesicles (MVs) are key markers in human body fluids that reflect cellular activation related to diseases as thrombosis. These MVs display phosphatidylserine at the outer leaflet of their plasma membrane as specific recognition moieties. The work reported in this manuscript focuses on the development of an original method where MVs are captured by bimetallic zinc complexes. A set of ligands have been synthetized based on a phenol spacer bearing in para position an amine group appended to a short or a longer alkyl chain (for grafting on surface) and bis(dipicolylamine) arms in ortho position (for zinc coordination). The corresponding dibridged zinc phenoxido and hydroxido complexes have been prepared in acetronitrile in presence of triethylamine and characterized by several spectroscopic techniques. The pH-driven interconversion studies for both complexes in H₂O:DMSO (70:30) evidence that at physiologic pH the main species are mono-bridged by the phenoxido spacer. An X-Ray structure obtained from complex 2 (based on the ligand with the amine group on the short chain) in aqueous medium confirms the presence of a mono-bridged complex. Then, the complexes have been used for interaction studies with short-chain phospholipids. Both have established the selective recognition of the anionic phosphatidylserine model versus zwitterionic phospholipids (in solution by ³¹P NMR and after immobilization on solid support by surface plasmon resonance (SPR)). Moreover, both complexes have also demonstrated their ability to capture MVs isolated from human plasma. These complexes are thus promising candidates for MVs probing by a new approach based on coordination chemistry.

Distinguishing Plasmin-Generating Microvesicles: Tiny Messengers Involved in Fibrinolysis and Proteolysis

A number of stressors and inflammatory mediators (cytokines, proteases, oxidative stress mediators) released during inflammation or ischemia stimulate and activate cells in blood, the vessel wall or tissues. The most well-known functional and phenotypic responses of activated cells are (1) the immediate expression and/or release of stored or newly synthesized bioactive molecules, and (2) membrane blebbing followed by release of microvesicles. An ultimate response, namely the formation of extracellular traps by neutrophils (NETs), is outside the scope of this work. The main objective of this article is to provide an overview on the mechanism of plasminogen reception and activation at the surface of cell-derived microvesicles, new actors in fibrinolysis and proteolysis. The role of microvesicle-bound plasmin in pathological settings involving inflammation, atherosclerosis, angiogenesis, and tumour growth, remains to be investigated. Further studies are necessary to determine if profibrinolytic microvesicles are involved in a finely regulated equilibrium with pro-coagulant microvesicles, which ensures a balanced haemostasis, leading to the maintenance of vascular patency.

Role of Circulating Exosomes in Cerebrovascular Diseases: A Comprehensive Review

Exosomes are lipid bilayer vesicles that contain multiple macromolecules secreted by the parent cells and play a vital role in intercellular communication. In recent years, the function of exosomes in cerebrovascular diseases (CVDs) has been intensively studied. Herein, we briefly review the current understanding of exosomes in CVDs. We discuss their role in the pathophysiology of the diseases and the value of the exosomes for clinical applications as biomarkers and potential therapies.

Extracellular vesicles mediate biological information delivery: A double-edged sword in cardiac remodeling after myocardial infarction

Acute myocardial infarction (AMI) is a severe ischemic disease with high morbidity and mortality worldwide. Maladaptive cardiac remodeling is a series of abnormalities in cardiac structure and function that occurs following myocardial infarction (MI). The pathophysiology of this process can be separated into two distinct phases: the initial inflammatory response, and the subsequent longer-term scar revision that includes the regression of inflammation, neovascularization, and fibrotic scar formation. Extracellular vesicles are nano-sized lipid bilayer vesicles released into the extracellular environment by eukaryotic cells, containing bioinformatic transmitters which are essential mediators of intercellular communication. EVs of different cellular origins play an essential role in cardiac remodeling after myocardial infarction. In this review, we first introduce the pathophysiology of post-infarction cardiac remodeling, as well as the biogenesis, classification, delivery, and functions of EVs. Then, we explore the dual role of these small molecule transmitters delivered by EVs in post-infarction cardiac remodeling, including the double-edged sword of pro-and anti-inflammation, and pro-and anti-fibrosis, which is significant for post-infarction cardiac repair. Finally, we discuss the pharmacological and engineered targeting of EVs for promoting heart repair after MI, thus revealing the potential value of targeted modulation of EVs and its use as a drug delivery vehicle in the therapeutic process of post-infarction cardiac remodeling.

The potential applications of microparticles in the diagnosis, treatment, and prognosis of lung cancer

Microparticles (MPs) are 100–1000 nm heterogeneous submicron membranous vesicles derived from various cell types that express surface proteins and antigenic profiles suggestive of their cellular origin. MPs contain a diverse array of bioactive chemicals and surface receptors, including lipids, nucleic acids, and proteins, which are essential for cell-to-cell communication. The tumour microenvironment (TME) is enriched with MPs that can directly affect tumour progression through their interactions with receptors. Liquid biopsy, a minimally invasive test, is a promising alternative to tissue biopsy for the early screening of lung cancer (LC). The diverse biomolecular information from MPs provides a number of potential biomarkers for LC risk assessment, early detection, diagnosis, prognosis, and surveillance. Remodelling the TME, which profoundly influences immunotherapy and clinical outcomes, is an emerging strategy to improve immunotherapy. Tumour-derived MPs can reverse drug resistance and are ideal candidates for the creation of innovative and effective cancer vaccines. This review described the biogenesis and components of MPs and further summarised their main isolation and quantification methods. More importantly, the review presented the clinical application of MPs as predictive biomarkers in cancer diagnosis and prognosis, their role as therapeutic drug carriers, particularly in anti-tumour drug resistance, and their utility as cancer vaccines. Finally, we discussed current challenges that could impede the clinical use of MPs and determined that further studies on the functional roles of MPs in LC are required.

Circulating Thrombomodulin: Release Mechanisms, Measurements, and Levels in Diseases and Medical Procedures

Thrombomodulin (TM) is a type-I transmembrane protein that is mainly expressed on endothelial cells and plays important roles in many biological processes. Circulating TM of different forms are also present in biofluids, such as blood and urine. Soluble TM (sTM), comprised of several domains of TM, is the major circulating TM which is generated by either enzymatic or chemical cleavage of the intact protein under different conditions. Under normal conditions, sTM is present in low concentrations (<10 ng/mL) in the blood but is elevated in several pathological conditions associated with endothelial dysfunction such as cardiovascular, inflammatory, infection, and metabolic diseases. Therefore, sTM level has been examined for monitoring disease development, such as disseminated intravascular coagulation (DIC), sepsis and multiple organ dysfunction syndrome in patients with novel coronavirus disease 2019 (COVID-19) recently. In addition, microvesicles (MVs) that contain membrane TM (MV-TM) have been found to be released from activated cells which also contribute to levels of circulating TM in certain diseases. Several release mechanisms of sTM and MV-TM have been reported, including enzymatic, chemical, and TM mutation mechanisms. Measurements of sTM and MV-TM have been developed and explored as biomarkers in many diseases. In this review, we summarize all these advances in three categories as follows: (1) release mechanisms of circulating TM, (2) methods for measuring circulating TM in biological samples, and (3) correlation of circulating TM with diseases. Altogether, it provides a whole picture of recent advances on circulating TM in health and disease.

Extracellular Vesicles and Hepatocellular Carcinoma: Opportunities and Challenges

The incidence of hepatocellular carcinoma (HCC) is increasing worldwide. Extracellular vesicles (EVs) contain sufficient bioactive substances and are carriers of intercellular information exchange, as well as delivery vehicles for nucleic acids, proteins and drugs. Although EVs show great potential for the treatment of HCC and their role in HCC progression has been extensively studied, there are still many challenges such as time-consuming extraction, difficult storage, easy contamination, and low drug loading rate. We focus on the biogenesis, morphological characteristics, isolation and extraction of EVs and their significance in the progression of HCC, tumor invasion, immune escape and cancer therapy for a review. EVs may be effective biomarkers for molecular diagnosis of HCC and new targets for tumor-targeted therapy.

Ischemic tissue released microvesicles induce monocyte reprogramming and increase tissue repair by a tissue factor-dependent mechanism

AIMS

Despite increasing evidence that monocytes may acquire endothelial features, it remains unclear how monocytes participate in angiogenesis after ischemic damage. We investigated whether ischemic cells can release microvesicles (MVs) and promote neovascularisation in a model of peripheral artery disease (PAD).

METHODS AND RESULTS

To model PAD we used an in vivo experimental model of hind limb ischemia (HLI) in mice. MVs were isolated from the ischemic muscle and from peripheral blood at different times after unilateral femoral artery ligation. MVs were phenotypically characterized to identify cell origin. HLI in mice induced the release of MVs with a much higher content of tissue factor (TF) than non-HLI control mice both in the MVs isolated from the affected limb muscle area and from blood. MVs were mainly released from endothelial cells (ECs) and induced Mo differentiation to endothelial cell-like (ECL) cells. Differentiation to ECL cells encompassed highly strict hierarchycal transcription factor activation, initiated by ETS1 activation. MVs secreted by microvascular ECs overexpressing TF (upTF-EMVs), were injected in the ischemic hind limb in parallel with control EMVs (from random siRNA-treated cells) or EMVs released by silenced TF endothelial cells (siTF-EMVs). In animals treated with upTF-EMVs in the ischemic zone there was a highly significant increase in functional new vessels formation (seen by magnetic resonance angiography), a concomitant increase in the pool of circulating Ly6Clow Mo expressing vascular endothelial cell markers, and a significantly higher number of Mo/Macrophages surrounding and integrating the newly formed collaterals.

CONCLUSION

Ischemia-activated ECs release EMVs rich in TF that induce monocyte differentiation into ECL cells and the formation of new vessels in the ischemic zone. TF by this mechanism of formation of new blood microvessels can contribute to ischemic tissue repair.

TRANSLATIONAL PERSPECTIVE

Neovascularization is the cornerstone of limb preservation in peripheral artery disease. Neovessel formation occurring during postnatal development is usually connected with inflammation. Advanced studies in the field of vascular biology have reported that monocytes can acquire endothelial features under angiogenic stimulation. We report that after ischemia affected endothelial cells release microvesicles rich in tissue factor that act as endogenous triggers by interacting with monocytes in an autocrine fashion, coaxing the cells to differentiate into functional endothelial cells. These differentiated cells have the ability to increase blood flow into ischemic tissue. The present study depicts a new concept in the mechanisms governing vessel formation in ischemic tissue.

Lysosome purinergic receptor P2X4 regulates neoangiogenesis induced by microvesicles from sarcoma patients

The tumor microenvironment modulates cancer growth. Extracellular vesicles (EVs) have been identified as key mediators of intercellular communication, but their role in tumor growth is largely unexplored. Here, we demonstrate that EVs from sarcoma patients promote neoangiogenesis via a purinergic X receptor 4 (P2XR4) -dependent mechanism in vitro and in vivo. Using a proteomic approach, we analyzed the protein content of plasma EVs and identified critical activated pathways in human umbilical vein endothelial cells (HUVECs) and human progenitor hematopoietic cells (CD34+). We then showed that vessel formation was due to rapid mitochondrial activation, intracellular Ca²⁺ mobilization, increased extracellular ATP, and trafficking of the lysosomal P2XR4 to the cell membrane, which is required for cell motility and formation of stable branching vascular networks. Cell membrane translocation of P2XR4 was induced by proteins and chemokines contained in EVs (e.g. Del-1 and SDF-1). Del-1 was found expressed in many EVs from sarcoma tumors and several tumor types. P2XR4 blockade reduced EVs-induced vessels in angioreactors, as well as intratumor vascularization in mouse xenografts. Together, these findings identify P2XR4 as a key mediator of EVs-induced tumor angiogenesis via a signaling mediated by mitochondria-lysosome-sensing response in endothelial cells, and indicate a novel target for therapeutic interventions.

Elucidating the Pivotal Neuroimmunomodulation of Stem Cells in Spinal Cord Injury Repair

Spinal cord injury (SCI) is a distressing incident with abrupt onset of the motor as well as sensory dysfunction, and most often, the injury occurs as result of high-energy or velocity accidents as well as contact sports and falls in the elderly. The key challenges associated with nerve repair are the lack of self-repair as well as neurotrophic factors and primary and secondary neuronal apoptosis, as well as factors that prevent the regeneration of axons locally. Neurons that survive the initial traumatic damage may be lost due to pathogenic activities like neuroinflammation and apoptosis. Implanted stem cells are capable of differentiating into neural cells that replace injured cells as well as offer local neurotrophic factors that aid neuroprotection, immunomodulation, axonal sprouting, axonal regeneration, and remyelination. At the microenvironment of SCI, stem cells are capable of producing growth factors like brain-derived neurotrophic factor and nerve growth factor which triggers neuronal survival as well as axonal regrowth. Although stem cells have proven to be of therapeutic value in SCI, the major disadvantage of some of the cell types is the risk for tumorigenicity due to the contamination of undifferentiated cells prior to transplantation. Local administration of stem cells via either direct cellular injection into the spinal cord parenchyma or intrathecal administration into the subarachnoid space is currently the best transplantation modality for stem cells during SCI.

Kidney Mesenchymal Stem Cell-derived Extracellular Vesicles Engineered to Express Erythropoietin Improve Renal Anemia in Mice with Chronic Kidney Disease

Extracellular vesicles (EVs) shed from kidney mesenchymal stem cells (KMSCs) show protective effects against acute kidney injury and progressive kidney fibrosis via mRNA transfer. Previous studies report improvement of renal anemia following administration of genetically modified MSCs or peritoneal mesothelial cells that secrete erythropoietin (EPO). Here, we determined whether EPO-secreting KMSC-derived EVs (EPO⁽⁺⁾-EVs) can improve renal anemia in mouse models of chronic kidney disease (CKD). The mouse CKD and renal anemia model was induced by electrocoagulation of the right renal cortex and sequential left nephrectomy. At six weeks post-nephrectomy, we observed significantly lower hemoglobin (10.4 ± 0.2 vs. 13.2 ± 0.2 g/dL) and significantly higher blood urea nitrogen and serum creatinine levels in CKD mice relative to controls (60.5 ± 0.5 and 0.37 ± 0.09 mg/dL vs. 19.9 ± 0.5 and 0.12 ± 0.02 mg/dL, respectively). Genetically engineered EPO⁽⁺⁾-KMSCs secreted 71 IU/mL EPO/10⁶ cells/24 h in vitro, and EPO⁽⁺⁾-EVs isolated by differential ultracentrifugation expressed EPO mRNA and horizontally transferred EPO mRNA into target cells in vitro and in vivo. Furthermore, at two weeks post-injection of EPO⁽⁺⁾-KMSCs or EPO⁽⁺⁾-EVs into CKD mice with renal anemia, we observed significant increases in hemoglobin levels (11.7 ± 0.2 and 11.5 ± 0.2 vs. 10.1 ± 0.2 g/dL, respectively) and significantly lower serum creatinine levels at eight weeks in comparison to mice receiving vehicle control (0.30 ± 0.00 and 0.23 ± 0.03 vs. 0.43 ± 0.06 mg/dL, respectively). These results demonstrate that intraperitoneal administration of EPO⁽⁺⁾-EVs significantly increased hemoglobin levels and renal function in CKD mice, suggesting the efficacy of these genetically engineered EVs as a promising novel strategy for the treatment of renal anemia.

TLR4 signaling induces the release of microparticles by tumor cells that regulate inflammatory cytokine IL-6 of macrophages via microRNA let-7b

Tumor cells expressing TLRs is generally recognized to mediate tumor inflammation. However, whether and how tumor TLR signaling pathways negatively regulate tumor inflammation remains unclear. In this report, we find that TLR4 signaling of H22 hepatocarcinoma tumor cells is transduced through MyD88 pathway to actin cytoskeletons, leading to the release of microparticles (MPs), the cellular membrane-derived vesicles. As a result, tumor macrophages take up MPs and acquire MP-contained microRNA let-7b, which attenuates tumor inflammation by targeting proinflammatory cytokine IL-6. Thus, tumor TLR signaling, contrary to the original promoting effect, may play an opposite role in downregulating tumor inflammation through MP pathways.

Activation of PAR2 by tissue factor induces the release of the PTEN from MAGI proteins and regulates PTEN and Akt activities

Tissue factor (TF) signalling has been associated with alterations in Akt activity influencing cellular survival and proliferation. TF is also shown to induce signalling through activation of the protease activated receptor (PAR)2. Seven cell lines were exposed to recombinant-TF (rec-TF), or activated using a PAR2-agonist peptide and the phosphorylation state of PTEN, and the activities of PTEN and Akt measured. Furthermore, by measuring the association of PTEN with MAGI proteins a mechanism for the induction of signalling by TF was proposed. Short term treatment of cells resulted in de-phosphorylation of PTEN, increased lipid-phosphatase activity and reduced Akt kinase activity in most of the cell lines examined. In contrast, continuous exposure to rec-TF up to 14 days, resulted in lower PTEN antigen levels, enhanced Akt activity and increased rate of cell proliferation. To explore the mechanism of activation of PTEN by TF, the association of "membrane-associated guanylate kinase-with inverted configuration" (MAGI)1–3 proteins with PTEN was assessed using the proximity ligation assay and by co-immunoprecipitation. The interaction of PTEN with all three MAGI proteins was transiently reduced following PAR2 activation and explains the changes in PTEN activity. Our data is first to show that PAR2 activation directly, or through exposure of cells to TF releases PTEN from MAGI proteins and is concurrent with increases in PTEN phosphatase activity. However, prolonged exposure to TF results in the reduction in PTEN antigen with concurrent increase in Akt activity which may explain the aberrant cell survival, proliferation and invasion associated with TF during chronic diseases.

High levels of endothelial and platelet microvesicles in patients with type 1 diabetes irrespective of microvascular complications

INTRODUCTION

Patients with type 1 diabetes have high risk of developing microvascular complications, and microangiopathy contributes to premature cardiovascular disease in this population. The role that microvesicles (MVs) may play in the development of microangiopathy in type 1 diabetes remains unclear.

MATERIALS AND METHODS

Plasma levels of endothelial MVs (EMVs) and platelet MVs (PMVs) in 130 patients with type 1 diabetes without microangiopathy, 106 patients with microangiopathy and 100 matched healthy controls were analyzed using flow cytometry. MV expression of procoagulant phosphatidylserine (PS) and proinflammatory high mobility group box-1 protein (HMGB1) was also assessed.

RESULTS

Patients with type 1 diabetes had markedly elevated levels of EMVs and PS+ EMVs as well as PMVs and PS+ PMVs compared to healthy controls (p < .001 for all). Furthermore, HMGB1+ EMVs and HMGB1+ PMVs were significantly increased in patients (p < .001 for all). After adjusting for potential confounders, there were no clear differences between patients with or without microvascular complications for any of the MV parameters.

CONCLUSION

Type 1 diabetes is a prothrombotic and proinflammatory disease state that, regardless of the presence of clinical microangiopathy, is associated with elevated levels of plasma MVs, in particular those of an endothelial origin. We have for the first time demonstrated that patients with type 1 diabetes have higher levels of HMGB1+ MVs. HMGB1 is an alarmin with potent proinflammatory effects that drive endothelial dysfunction, and it would therefore be of interest to further study the role of HMGB1+ MVs in the development of macrovascular complications in type 1 diabetes.

Elevated Microparticles, Thrombin-antithrombin and VEGF Levels in Colorectal Cancer Patients Undergoing Chemotherapy

Hypercoagulable state and neoangiogenesis are common phenomena associated with malignancy. Cancer patients have increased levels of circulating endothelium-derived microparticles (EMPs), which have been hypothesized to be involved in numerous pathophysiological processes. Hemostasis and angiogenesis are also activated in colorectal cancer (CRC) patients. The study aimed to investigate potential influence of chemotherapy on EMPs, thrombin anti-thrombin complex (TAT) and vascular endothelial growth factor (VEGF) levels in CRC patients undergoing chemotherapy. The study group consisted of 18 CRC patients: 8 stage III colon cancer (CC) and 10 stage IV rectal cancer (RC) patients. EMPs, TAT and VEGF levels were assessed before chemotherapy and after the third course. Results were compared with 10 healthy subjects. EMP concentration was measured by flow cytometry, while TAT and VEGF concentrations were assayed employing ELISA. Compared to the control group, CC and RC patients had significantly higher levels of tissue factor (TF)-bearing and non-TF-bearing EMPs before and after three courses of chemotherapy. VEGF concentrations in CRC patients were higher than in the control groups and increased following chemotherapy. TAT levels were elevated in CRC patients before chemotherapy compared to healthy subjects and significantly increased after the third course of chemotherapy. No significant correlation was found either between EMP and TAT levels, or between EMP concentrations and VEGF levels in the study group. CRC patients have increased EMPs, and TAT as well as VEGF levels tend to increase during chemotherapy.

Subventricular zone-derived extracellular vesicles promote functional recovery in rat model of spinal cord injury by inhibition of NLRP3 inflammasome complex formation

Spinal cord injury (SCI) is the destruction of spinal cord motor and sensory resulted from an attack on the spinal cord, which can cause significant physiological damage. The inflammasome is a multiprotein oligomer resulting in inflammation; the NLRP3 inflammasome composed of NLRP3, apoptosis-associated speck-like protein (ASC), procaspase-1, and cleavage of procaspase-1 into caspase-1 initiates the inflammatory response. Subventricular Zone (SVZ) is the origin of neural stem/progenitor cells (NS/PCs) in the adult brain. Extracellular vesicles (EVs) are tiny lipid membrane bilayer vesicles secreted by different types of cells playing an important role in cell-cell communications. The aim of this study was to investigate the effect of intrathecal transplantation of EVs on the NLRP3 inflammasome formation in SCI rats. Male wistar rats were divided into three groups as following: laminectotomy group, SCI group, and EVs group. EVs was isolated from SVZ, and characterized by western blot and DLS, and then injected into the SCI rats. Real-time PCR and western blot were carried out for gene expression and protein level of NLRP3, ASC, and Caspase-1. H&E and cresyl violet staining were performed for histological analyses, as well as BBB test for motor function. The results indicated high level in mRNA and protein level in SCI group in comparison with laminectomy (p < 0.001), and injection of EVs showed a significant reduction in the mRNA and protein levels in EVs group compared to SCI (p < 0.001). H&E and cresyl violet staining showed recovery in neural cells of spinal cord tissue in EVs group in comparison with SCI group. BBB test showed the promotion of motor function in EVs group compared to SCI in 14 days (p < 0.05). We concluded that the injection of EVs could recover the motor function in rats with SCI and rescue the neural cells of spinal cord tissue by suppressing the formation of the NLRP3 inflammasome complex.

Endothelial Extracellular Vesicles Produced by Senescent Cells: Pathophysiological Role in the Cardiovascular Disease Associated with all Types of Diabetes Mellitus

Endothelial senescence-associated with aging or induced prematurely in pathological situations, such as diabetes, is a first step in the development of Cardiovascular Disease (CVDs) and particularly inflammatory cardiovascular diseases. The main mechanism that links endothelial senescence and the progression of CVDs is the production of altered Extracellular Vesicles (EVs) by senescent endothelial cells among them, Microvesicles (MVs). MVs are recognized as intercellular signaling elements that play a key role in regulating tissue homeostasis. However, MVs produced by damage cell conveyed epigenetic signals, mainly involving microRNAs, which induce many of the injured responses in other vascular cells leading to the development of CVDs. Many studies strongly support that the quantification and characterization of the MVs released by senescent endothelial cells may be useful diagnostic tools in patients with CVDs, as well as a future therapeutic target for these diseases. In this review, we summarize the current knowledge linking senescence-associated MVs to the development of CVDs and discuss the roles of these MVs, in particular, in diabetic-associated increases the risk of CVDs.

MicroRNA-421-3p-abundant small extracellular vesicles derived from M2 bone marrow-derived macrophages attenuate apoptosis and promote motor function recovery via inhibition of mTOR in spinal cord injury

Background

Spinal cord injury (SCI) has a very disabling central nervous system impact but currently lacks effective treatment. Bone marrow-derived macrophages (BMDMs) are recruited to the injured area after SCI and participate in the regulation of functional recovery with microglia. Previous studies have shown that M2 microglia-derived small extracellular vesicles (SEVs) have neuroprotective effects, but the effects of M2 BMDM-derived sEVs (M2 BMDM-sEVs) have not been reported in SCI treatment.

Results

In this study, we investigated the role of M2 BMDM-sEVs in vivo and in vitro for SCI treatment and its mechanism. Our results indicated that M2 BMDM-sEVs promoted functional recovery after SCI and reduced neuronal apoptosis in mice. In addition, M2 BMDM-sEVs targeted mammalian target of rapamycin (mTOR) to enhance the autophagy level of neurons and reduce apoptosis. MicroRNA-421-3P (miR-421-3p) can bind to the 3′ untranslated region (3′UTR) of mTOR. MiR-421-3p mimics significantly reduced the activity of luciferase-mTOR 3′UTR constructs and increased autophagy. At the same time, tail vein injection of inhibitors of SEVs (Inh-sEVs), which were prepared by treatment with an miR-421-3p inhibitor, showed diminished protective autophagy of neuronal cells in vivo.

Conclusions

In conclusion, M2 BMDM-sEVs inhibited the mTOR autophagy pathway by transmitting miR-421-3p, which reduced neuronal apoptosis and promoted functional recovery after SCI, suggesting that M2 BMDM-sEVs may be a potential therapy for SCI.

Mesenchymal and Induced Pluripotent Stem Cells-Derived Extracellular Vesicles: The New Frontier for Regenerative Medicine?

Regenerative medicine aims to repair damaged, tissues or organs for the treatment of various diseases, which have been poorly managed with conventional drugs and medical procedures. To date, multimodal regenerative methods include transplant of healthy organs, tissues, or cells, body stimulation to activate a self-healing response in damaged tissues, as well as the combined use of cells and bio-degradable scaffold to obtain functional tissues. Certainly, stem cells are promising tools in regenerative medicine due to their ability to induce de novo tissue formation and/or promote organ repair and regeneration. Currently, several studies have shown that the beneficial stem cell effects, especially for mesenchymal stem cells (MSCs) and induced pluripotent stem cells (iPSCs) in damaged tissue restore are not dependent on their engraftment and differentiation on the injury site, but rather to their paracrine activity. It is now well known that paracrine action of stem cells is due to their ability to release extracellular vesicles (EVs). EVs play a fundamental role in cell-to-cell communication and are directly involved in tissue regeneration. In the present review, we tried to summarize the molecular mechanisms through which MSCs and iPSCs-derived EVs carry out their therapeutic action and their possible application for the treatment of several diseases.

Extracellular microparticles exacerbate oxidative damage to retinal pigment epithelial cells

Oxidative stress-induced retinal pigment epithelial cell (RPE) dysfunction is a primary contributing factor to early dry age-related macular degeneration (AMD). Oxidative injury to the retina may promote extracellular vesicles (EVs) released from RPE. In this study, we investigated the effects of oxidative-induced RPE cell-derived microparticles (RMPs) on RPE cell functions. The oxidative stress induced more RMPs released from RPE cells in vitro and in vivo, and significant more RMPs were released from aged RPE cells than that from younger RPE cells. RMPs were taken up by RPE cells in a time-dependent manner; however, blockage of CD36 attenuated the uptake process. Furthermore, the decrease of RPE cell viability by RMPs treatment was associated with an increased expression of cyclin-dependent kinase inhibitors p15 and p21. RMPs enhanced senescence and interrupted phagocytic activity of RPE cells as well. The present study demonstrated that RMPs produce a strong effect of inducing RPE cell degeneration. This finding further supports the postulate that RMPs exacerbate oxidative stress damage to RPE cells, which may uncover a potentially relevant process in the genesis of dry AMD.

Phosphatidylserine Externalization Results from and Causes Neurite Degeneration in Drosophila

Phagocytic clearance of degenerating dendrites or axons is critical for maintaining tissue homeostasis and preventing neuroinflammation. Externalized phosphatidylserine (PS) has been postulated to be an ‘‘eat-me’’ signal allowing recognition of degenerating neurites by phagocytes. Here we show that in Drosophila, PS is dynamically exposed on degenerating dendrites during developmental pruning and after physical injury, but PS exposure is suppressed when dendrite degeneration is genetically blocked. Ectopic PS exposure via phospholipid flippase knockout and scramblase overexpression induced PS exposure preferentially at distal dendrites and caused distinct modes of neurite loss that differ in larval sensory dendrites and in adult olfactory axons. Surprisingly, extracellular lactadherin that lacks the integrin-interaction domain induced phagocyte-dependent degeneration of PS-exposing dendrites, revealing an unidentified bridging function that potentiates phagocytes. Our findings establish a direct causal relationship between PS exposure and neurite degeneration in vivo.

Using in vivo phosphatidylserine (PS) sensors, Sapar et al. reveal dynamic patterns of PS exposure on degenerating dendrites in Drosophila. Flippase knockout and scramblase overexpression lead to ectopic PS exposure on distal dendrites and context-dependent neurite degeneration. Lactadherin potentiates phagocytes to destruct PS-exposing dendrites, independent of its integrin-interaction domain.

A Protocol for Non-biased Identification of RNAs Transferred Between Heterologous Mammalian Cell Types Using RNA Tagging, Cell Sorting, and Sequencing

Intercellular communication is a major hallmark of multicellular organisms and is responsible for coordinating cell and tissue differentiation, immune responses, synaptic transmission, and both paracrine and endocrine signaling, for example. Small molecules, peptides, and proteins have all been studied extensively as mediators of intercellular communication; however, RNAs have also been shown recently to transfer between cells. In mammalian cells, microRNAs, tRNAs, short noncoding RNAs, mRNA fragments, as well as full-length mRNAs have all been shown to transfer between cells either by exosomes or by membrane nanotubes. We have previously described nanotube-mediated cell-cell transfer of specific mRNAs between heterologous mammalian cell types cultured in vitro. Here, we describe a simple method for the unbiased and quantitative identification of the complete range of transferred mRNAs (i.e., the mRNA transferome) in one population of mammalian cells following co-culture with another population. After co-culture, the individual cell populations are sorted by magnetic bead-mediated cell sorting and the transferred RNAs are then identified by downstream analysis methods, such as RNA sequencing. Application of this technique not only allows for determination of the mRNA transferome, but can also reveal changes in the native transcriptome of a cell population after co-culture. This can indicate the effect that co-culture and intercellular transfer of mRNA have upon cell physiology.

The potential diagnostic power of CD138+ microparticles from the plasma analysis for multiple myeloma clinical monitoring

Multiple myeloma (MM) is malignant tumor with abnormal proliferation of bone marrow plasma cells. The existing clinical tools used to determine treatment response and tumor relapse are limited in sensitivity. We investigated the CD138+ microparticles (MPs) of MM patients to find out whether MPs could provide a novel means to monitor the malignant cells in MM patients. Our study showed that the levels of MPs were significantly elevated in MM patients. The MP counts in peripheral blood from new diagnosed MM patients were significantly higher than patients in CR and HD. Consist with the total MPs, the number of the PC-derived MPs (CD138+) increased in BM from MM patients compared with CR and HD. The ratio of the PC-derived MPs (CD138+) in BM increased in MM patients compared with CR and HD. The correlation test revealed that the CD138+ MPs in BM and PB were all positively correlated with the plasmacyte ratio in bone marrow (BMPC) and the β₂ -MG. New diagnosed MM patients and controls were compared, and ROC curves were used to identify cutoff points with optimal sensitivity and specificity concerning the ratios and counts of CD138+ MPs in BM and PB. The AUC of the CD138+ MP counts in BM was 0.767, and in PB was 0.680. The AUC of the CD138+ MP ratios in BM was 0.714, and in PB was 0.666. According to this, the counts of CD138+ MPs in BM showed to be a powerful marker of diagnosis. We demonstrated that CD138+ MPs from the plasma provide support for a potential monitoring biomarker of MM.

Extracellular vesicles derived from pancreatic cancer cells BXPC3 or breast cancer cells MCF7 induce a permanent procoagulant shift to endothelial cells

The endothelium could be a potential target of cancer cell derived extracellular vesicles (CaCe-dEV). We investigated in vitro the effect of CaCe-dEV on the hemostatic balance of endothelial cells. Extracellular vesicles released from pancreas adenocarcinoma cells (BXPC3) or human breast cancer cells (MCF7) were isolated by differential centrifugation. Human umbilical vein endothelial cells (HUVEC) were cultured for 72 h in the presence or absence of CaCe-dEV. Subsequently, they were washed and re-cultivated over three cycles to get daughter cell generations (DG) which were not exposed to CaCe-dEV. Thrombin generation of normal platelet poor plasma (PPP) added in wells carrying HUVEC was assessed by the Calibrated Automated Thrombogram®. Tissue factor activity (TFa) and procoagulant phospholipid clotting time were assessed. Some traces of TFa were displayed by non-exposed HUVEC (0.18 ± 0.03 pM) and their EVs (1.2 ± 1.0 pM). Non-exposed HUVEC did not induce any detectable thrombin generation. BXPC3-dEV displayed significantly higher TFa as compared to MCF7-dEV (45 ± 5 pM versus 4.6 ± 2.3pM respectively; p < 0.05). HUVEC exposed to CaCe-dEV enhanced thrombin generation. BXPC3-dEV induced significantly higher thrombin generation as compared to those exposed to MCF7-dEV. The procoagulant properties of HUVEC, acquired upon exposure to CaCe-dEV were transferred to DG. In conclusion, CaCe-dEV lead to a procoagulant shift of endothelial cells which, upon exposure, display TFa and enhance thrombin generation which is transferred to DG of HUVEC. The potency of CaCe-dEV to induce procoagulant shift of HUVEC depends on the histological type of the cancer cells. The procoagulant shift of endothelial cells which is transferable to DG could be an additional mechanism - together with cancer-induced blood hypercoagulability - in the pathogenesis of cancer associated thrombosis.

Microparticles and autophagy: a new frontier in the understanding of atherosclerosis in rheumatoid arthritis

Microparticles (MPs) are small membrane vesicles released by many cell types under physiological and pathological conditions. In the last years, these particles were considered as inert cell debris, but recently many studies have demonstrated they could have a role in intercellular communication. Increased levels of MPs have been reported in various pathological conditions including infections, malignancies, and autoimmune diseases, such as rheumatoid arthritis (RA). RA is an autoimmune systemic inflammatory disease characterized by chronic synovial inflammation, resulting in cartilage and bone damage with accelerated atherosclerosis increasing mortality. According to the literature data, also MPs could have a role in endothelial dysfunction, contributing to atherosclerosis in RA patients. Moreover many researchers have shown that a dysregulated autophagy seems to be involved in endothelial dysfunction. Autophagy is a reparative process by which cytoplasmic components are sequestered in double-membrane vesicles and degraded on fusion with lysosomal compartments. It has been shown in many works that basal autophagy is essential to proper vascular function. Taking into account these considerations, we hypothesized that in RA patients MPs could contribute to atherosclerosis process by dysregulation of endothelial autophagy process.

Bone marrow mesenchymal stem cell-derived exosomes attenuate D-GaIN/LPS-induced hepatocyte apoptosis by activating autophagy in vitro

Background

Acute liver failure is an inflammation-mediated hepatocyte injury. Mesenchymal stem cell (MSC) transplantation is currently considered to be an effective treatment strategy for acute liver failure. Exosomes are an important paracrine factor that can be used as a direct therapeutic agent. However, the use of bone marrow mesenchymal stem cell-derived exosomes (BMSC-Exos) in the treatment of acute liver failure has not been reported.

Purpose

Here, we established a model of hepatocyte injury and apoptosis induced by D-galactosamine and lipopolysaccharide (D-GalN/LPS) to study the protective effect of BMSC-Exos on hepatocyte apoptosis, and further explored its protective mechanism.

Methods

BMSC-Exos was identified by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and Western blot. Laser confocal microscopy was used to observe the uptake of Dil-Exos by hepatocytes. D-GalN/LPS-induced primary hepatocytes were pretreated with BMSC-Exos in vitro, and then the cells were harvested. The apoptosis of hepatocytes was observed by TUNEL staining, flow cytometry and Western blot. Electron microscopy and mRFP-GFP-LC3 and Western blot was used to observe autophagy.

Results

BMSC-Exos increased the expression of autophagy marker proteins LC3 and Beclin-1 and promoted the formation of autophagosomes. After BMSC-Exos treatment, the expression levels of the proapoptotic proteins Bax and cleaved caspase-3 were significantly decreased, while the expression level of the anti-apoptotic protein Bcl-2 was upregulated. However, when the autophagy inhibitor 3MA was present, the effect of BMSC-Exos on inhibiting apoptosis was significantly reversed.

Conclusions

Our results showed for the first time that BMSC-Exos had the potential to reduce hepatocyte apoptosis after acute liver failure. In particular, we found that BMSC-Exos attenuated hepatocyte apoptosis by promoting autophagy. 

The Ratio of Factor VIIa:Tissue Factor Content within Microvesicles Determines the Differential Influence on Endothelial Cells

Tissue factor (TF)-positive microvesicles from various sources can promote cellular proliferation or alternatively induce apoptosis, but the determining factors are unknown. In this study the hypothesis that the ratio of fVIIa:TF within microvesicles determines this outcome was examined. Microvesicles were isolated from HepG2, BxPC-3, 786-O, MDA-MB-231, and MCF-7 cell lines and microvesicle-associated fVIIa and TF antigen and activity levels were measured. Human coronary artery endothelial cells (HCAECs) were incubated with these purified microvesicles, or with combinations of fVIIa-recombinant TF, and cell proliferation/apoptosis was measured. Additionally, by expressing mCherry-PAR2 on HCAEC surface, PAR2 activation was quantified. Finally, the activation of PAR2 on HCAEC or the activities of TF and fVIIa in microvesicles were blocked prior to addition of microvesicles to cells. The purified microvesicles exhibited a range of fVIIa:TF ratios with HepG2 and 786-O cells having the highest (54:1) and lowest (10:1) ratios, respectively. The reversal from proapoptotic to proliferative was estimated to occur at a fVIIa:TF molar ratio of 15:1, but HCAEC could not be rescued at higher TF concentrations. The purified microvesicles induced HCAEC proliferation or apoptosis according to this ruling. Blocking PAR2 activation on HCAEC, or inhibiting fVIIa or TF-procoagulant function on microvesicles prevented the influence on HCAEC. Finally, incubation of HCAEC with recombinant TF resulted in increased surface exposure of fVII. The induction of cell proliferation or apoptosis by TF-positive microvesicles is dependent on the ratio of fVIIa:TF and involves the activation of PAR2. At lower TF concentrations, fVIIa can counteract the proapoptotic stimulus and induce proliferation.

Neural stem cell-derived small extracellular vesicles attenuate apoptosis and neuroinflammation after traumatic spinal cord injury by activating autophagy

Spinal cord injury (SCI) can cause severe irreversible motor dysfunction and even death. Neural stem cell (NSC) transplantation can promote functional recovery after acute SCI in experimental animals, but numerous issues, including low-transplanted cell survival rate, cell de-differentiation, and tumor formation need to be resolved before routine clinical application is feasible. Recent studies have shown that transplanted stem cells facilitate regeneration through release of paracrine factors. Small extracellular vesicles (sEVs), the smallest known membrane-bound nanovesicles, are involved in complex intercellular communication systems and are an important vehicle for paracrine delivery of therapeutic agents. However, the application of NSC-derived small extracellular vesicles (NSC-sEVs) to SCI treatment has not been reported. We demonstrate that NSC-sEVs can significantly reduce the extent of SCI, improve functional recovery, and reduce neuronal apoptosis, microglia activation, and neuroinflammation in rats. Furthermore, our study suggests that NSC-sEVs can regulate apoptosis and inflammatory processes by inducing autophagy. In brief, NSC-sEVs increased the expression of the autophagy marker proteins LC3B and beclin-1, and promoted autophagosome formation. Following NSC-sEV infusion, the SCI area was significantly reduced, and the expression levels of the proapoptotic protein Bax, the apoptosis effector cleaved caspase-3, and the pro-inflammatory cytokines TNF-α, IL-1β, and IL-6 were significantly reduced, whereas the expression level of the anti-apoptotic protein Bcl-2 was upregulated. In the presence of the autophagy inhibitor 3MA, however, these inhibitory effects of NSC-sEVs on apoptosis and neuroinflammation were significantly reversed. Our results show for the first time that NSC-sEV treatment has the potential to reduce neuronal apoptosis, inhibit neuroinflammation, and promote functional recovery in SCI model rats at an early stage by promoting autophagy.

Exo-circRNAs: a new paradigm for anticancer therapy

CircRNAs, as new members of long noncoding RNAs, have been the focus of recent investigation. CircRNAs feature a closed continuous loop structure without 5′-3′ polarity or a poly A tail. Many studies have reported the potential application of circRNAs in the clinic as new biomarkers and therapeutic targets in different diseases, especially for cancer. Additionally, the exosomes are important vehicles in cell-to-cell communication. And exo-circRNAs are circRNAs in exosomes which can be detected to provide additional evidence for conventional diagnostic methods and can be applied to suppress the malignant progress in cancer. In this review, we describe the biogenesis, characteristics, and functions of circRNAs and exosomes. Specifically, we present a comprehensive update of the promising role of exo-circRNAs in anticancer therapy.

TNFα expressed on the surface of microparticles modulates endothelial cell fate in rheumatoid arthritis

Background

Rheumatoid arthritis (RA) is associated with a high prevalence of atherosclerosis. Recently increased levels of microparticles (MPs) have been reported in patients with RA. MPs could represent a link between autoimmunity and endothelial dysfunction by expressing tumor necrosis factor alpha (TNFα), a key cytokine involved in the pathogenesis of RA, altering endothelial apoptosis and autophagy. The aim of this study was to investigate TNFα expression on MPs and its relationship with endothelial cell fate.

Methods

MPs were purified from peripheral blood from 20 healthy controls (HC) and from 20 patients with RA, before (time (T)0) and after (T4) 4-month treatment with etanercept (ETA). Surface expression of TNFα was performed by flow cytometry analysis. EA.hy926 cells, an immortalized endothelial cell line, were treated with RA-MPs purified at T0 and at T4 and also, with RA-MPs in vitro treated with ETA. Apoptosis and autophagy were then evaluated.

Results

RA-MPs purified at T0 expressed TNFα on their surface and this expression significantly decreased at T4. Moreover, at T0 RA-MPs, significantly increased both apoptosis and autophagy levels on endothelial cells, in a dose-dependent manner. RA-MPs did not significantly change these parameters after 4 months of in vivo treatment with ETA.

Conclusions

Our data demonstrate that MPs isolated from patients with RA exert a pathological effect on endothelial cells by TNFα expressed on their surface. In vivo and in vitro treatment with ETA modulates this effect, suggesting anti-TNF therapy protects against endothelial damage in patients with RA.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1768-8) contains supplementary material, which is available to authorized users.

New Insights Into Immune Cell-Derived Extracellular Vesicles in Multiple Sclerosis

Extracellular vesicles (EVs) are small vesicles including microvesicles and exosomes which differ in their distinct size, density, biogenesis, and content. Until recently, EVs were considered as simply scrap products. Nowadays, they are engendering huge interest and their shedding plays a well-recognized role in intercellular communication, not only participating in many physiological processes, but also suspected of being involved in the pathogenesis of many diseases. The present review aims to summarize the latest updates on immune cell-derived EVs, focusing on the current status of knowledge in Multiple Sclerosis. Significant progress has been made on their physical and biological characterization even though many aspects remain unclear and need to be addressed. However, it is worth further investigating in order to deepen the knowledge of this unexplored and fascinating field that could lead to intriguing findings in the evaluation of EVs as biomarkers in monitoring the course of diseases and the response to treatments.

Relationship between cardiovascular diseases and circulating cell-free nucleic acids in human plasma

Cardiovascular diseases (CVDs) are the main cause of human morbidity and mortality worldwide. Early diagnosis could improve the efficiency of treatments. New biomarkers are needed for the identification of high-risk populations in order to make accurate diagnosis and therapy monitoring. Circulating cell-free nucleic acids (cf-NAs) offer a promising new noninvasive tool. These have a role in the regulation of normal physiological functions and in the development of pathological alterations. There is extended research on the clinical application and utilization of cell-free genomic DNA, mtDNA, mRNA, miRNA and long noncoding RNA in CVDs. These molecules could serve as components of new generation therapeutics. Our review focuses on the role of cf-NAs in the pathogenesis of CVDs and we are discussing also possible diagnostic applications and therapeutic implications.

Sensitive and Specific Detection of Platelet-Derived and Tissue Factor-Positive Extracellular Vesicles in Plasma Using Solid-Phase Proximity Ligation Assay

Extracellular vesicles (EVs) derived from blood cells are promising biomarkers for various diseases. However, they are difficult to measure accurately in plasma due to their small size. Here, we demonstrate that platelet-derived EVs in plasma can be measured using solid-phase proximity ligation assay with high sensitivity and specificity using very small sample volume of biological materials. The results correlate well with high-sensitivity flow cytometry with the difference that the smallest EVs are detected. Briefly, the EVs are first captured on a solid phase, using lactadherin binding, and detection requires recognition with two antibodies followed by qPCR. The assay, using cholera toxin subunit-B or lactadherin as capture agents, also allowed detection of the more rare population of tissue factor (TF)-positive EVs at a concentration similar to sensitive TF activity assays. Thus, this assay can detect different types of EVs with high specificity and sensitivity, and has the potential to be an attractive alternative to flow cytometric analysis of preclinical and clinical samples. Improved techniques for measuring EVs in plasma will hopefully contribute to the understanding of their role in several diseases.

Coagulation parameters following equine herpesvirus type 1 infection in horses

BACKGROUND

Equine herpesvirus type 1 (EHV-1) is the cause of respiratory disease, abortion storms, and outbreaks of herpesvirus myeloencephalopathy (EHM). Infection of the spinal cord is characterised by multifocal regions of virally infected vascular endothelium, associated with vasculitis, thrombosis and haemorrhage that result in ischaemia and organ dysfunction. However, the mechanism of thrombosis in affected horses is unknown.

OBJECTIVES

To evaluate tissue factor (TF) procoagulant activity and thrombin-antithrombin complex (TAT) levels in horses following infection with EHV-1.

STUDY DESIGN

In vitro and in vivo studies following experimental EHV-1 infection.

METHODS

Horses were infected with EHV-1 and levels of peripheral blood mononuclear cell (PBMC)-associated TF activity; plasma and cerebrospinal fluid (CSF)-derived microvesicle (MV)-associated TF activity and TAT complexes in plasma were examined.

RESULTS

EHV-1 infection increased PBMC TF procoagulant activity in vitro and in vivo. In infected horses, this increase was observed during the acute infection and was most marked at the onset and end of viraemia. However, no significant differences were observed between the horses that showed signs of EHM and the horses that did not develop EHM. Significant changes in MV-associated TF procoagulant activity and TAT complexes were not observed in infected horses.

MAIN LIMITATIONS

A small number of horses typically exhibit clinical EHM following experimental infection.

CONCLUSIONS

The results indicate that EHV-1 infection increases PBMC-associated TF procoagulant activity in vivo and in vitro. Additional in vivo studies are needed to better understand the role of TF-dependent coagulation during EHM pathogenesis in horses.

Dexamethasone-Activated MSCs Release MVs for Stimulating Osteogenic Response

The extracellular microvesicles (MVs) are attracting much attention because they are found to be the key paracrine mediator participating in tissue regeneration. Dexamethasone (DXM) is widely accepted as an important regulator in tailoring the differentiation potential of mesenchymal stem cells (MSCs). However, the effect of DXM on the paracrine signaling of MSCs remains unknown. To this point, we aimed to explore the role of DXM in regulating the paracrine activity of MSCs through evaluating the release and function of MSC-MVs, based on their physicochemical characteristics and support on osteogenic response. Results showed that DXM had no evident impact on the release of MSC-MVs but played a pivotal role in regulating the function of MSC-MVs. MVs obtained from the DXM-stimulated MSCs (DXM-MVs) increased MC3T3 cell proliferation and migration and upregulated Runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), and osteopontin (OPN) expression. The repair efficiency of DXM-MVs for femur defects was further investigated in an established rat model. It was found that DXM-MVs accelerated the healing process of bone formation in the defect area. Thus, we conclude that using DXM as stimuli to obtain functional MSCs-MVs could become a valuable tool for promoting bone regeneration.

Microparticles of healthy origins improve endothelial progenitor cell dysfunction via microRNA transfer in an atherosclerotic hamster model

AIM

In this study, we aimed: (i) to obtain and functionally characterize the cultures of late endothelial progenitor cells (EPCs) from the animal blood; (ii) to investigate the potential beneficial effects of circulating microparticles (MPs) of healthy origins on EPC dysfunctionality in atherosclerosis as well as involved mechanisms.

METHODS

Late EPCs were obtained and expanded in culture from peripheral blood isolated from two animal groups: hypertensive-hyperlipidaemic (HH) and control (C) hamsters. In parallel experiments, late EPC cultures from HH were incubated with MPs from C group.

RESULTS

The results showed that late EPCs display endothelial cell phenotype: (i) have ability to uptake 1,1-dioctadecyl-3,3,3,3 tetramethylindocarbocyanine-labelled acetylated low-density lipoprotein and Ulex europaeus agglutinin lectin-1; (ii) express CD34, CD133, KDR, CD144, vWF, Tie-2. Late EPCs from HH exhibited different morphological and functional characteristics compared to control: (i) are smaller and irregular in shape; (ii) present decreased endothelial surface marker expression; (iii) display reduced proliferation, migration and adhesion; (iv) lose ability to organize themselves into tubular structures and integrate into vascular network; (v) have diminished function of inward rectifier potassium channels. The incubation of late EPCs with MPs improved EPC functionality by miR-10a, miR-21, miR-126, miR-146a, miR-223 transfer and IGF-1 expression activation; the kinetic study of MP incorporation into EPCs demonstrated MP uptake by EPCs followed by the miRNA transfer.

CONCLUSION

The data reveal that late EPCs from atherosclerotic model exhibit distinctive features and are dysfunctional, and their function recovery can be supported by MP ability to transfer miRNAs. These findings bring a new light on the vascular repair in atherosclerosis.

Atorvastatin reduces thrombin generation and expression of tissue factor, P-selectin and GPIIIa on platelet-derived microparticles in patients with peripheral arterial occlusive disease

We investigated the effects of statin treatment on platelet-derived microparticles (PMPs) and thrombin generation in atherothrombotic disease. Nineteen patients with peripheral arterial occlusive disease were randomised to eight weeks of treatment with atorvastatin or placebo in a cross-over fashion. Expression of GPIIIa (CD61), P-selectin (CD62P), tissue factor (TF, CD142) and phosphatidylserine (PS; annexin-V or lactadherin binding) was assessed on PMPs. Thrombin generation in vivo was assessed by measurement of prothrombin fragment 1+2 in plasma (F1+2) and ex vivo by using the calibrated automated thrombogram (CAT). During atorvastatin treatment, expression of TF, P-selectin and GPIIIa was significantly reduced vs. placebo (p<0.001 for all). No effect on annexin-V or lactadherin binding was seen. Thrombin generation was significantly reduced during atorvastatin as assessed by both the CAT assay (p<0.001) and by measurements of F1+2 (p<0.01). Subsequent in vitro experiments showed that when TF on microparticles (MPs) was blocked by antibodies, the initiation of thrombin generation was slightly but significantly delayed. Blocking PS on MPs using annexin-V or lactadherin resulted in almost complete inhibition of thrombin generation. In conclusion, atorvastatin reduces thrombin generation and expression of TF, GPIIIa and P-selectin on PMPs in patients with peripheral vascular disease. Microparticle-bound TF slightly enhances initiation of thrombin generation whereas negatively charged surfaces provided by MPs or lipoproteins could reinforce thrombin generation. Statins may inhibit initiation of thrombin generation partly through a microparticle dependent mechanism but the main effect is probably through reduction of lipoprotein levels.

Pharmacological modulation of procoagulant microparticles improves haemodynamic dysfunction during septic shock in rats

Circulating microparticles play a pro-inflammatory and procoagulant detrimental role in the vascular dysfunction of septic shock. It was the objective of this study to investigate mechanisms by which a pharmacological modulation of microparticles could affect vascular dysfunction in a rat model of septic shock. Septic or sham rats were treated by activated protein C (aPC) and resuscitated during 4 hours. Their microparticles were harvested and inoculated to another set of healthy recipient rats. Haemodynamic parameters were monitored, circulating total procoagulant microparticles assessed by prothrombinase assay, and their cell origin characterised. Mesenteric resistance arteries, aorta and heart were harvested for western blotting analysis. We found that a) the amount and phenotype of circulating microparticles were altered in septic rats with an enhanced endothelial, leucocyte and platelet contribution; b) aPC treatment significantly reduced the generation of leucocyte microparticles and norepinephrine requirements to reach the mean arterial pressure target in septic rats; c) Microparticles from untreated septic rats, but not from aPC-treated ones, significantly reduced the healthy recipients’ mean arterial pressure; d) Microparticle thromboxane content and aPC activity were significantly increased in aPC-treated septic rats. In inoculated naïve recipients, microparticles from aPC-treated septic rats prompted reduced NF-κB and cyclooxygenase-2 arterial activation, blunted the generation of pro-inflammatory iNOS and secondarily increased platelet and endothelial microparticles. In conclusion, in this septic shock model, increased circulating levels of procoagulant microparticles led to negative haemodynamic outcomes. Pharmacological treatment by aPC modified the cell origin and levels of circulating microparticles, thereby limiting vascular inflammation and favouring haemodynamic improvement.

Liraglutide mitigates TNF-α induced pro-atherogenic changes and microvesicle release in HUVEC from diabetic women

BACKGROUND

To evaluate whether exposure to GLP-1 receptor agonist Liraglutide could modulate pro-atherogenic alterations previously observed in endothelial cells obtained by women affected by gestational diabetes (GD), thus exposed in vivo to hyperglycemia, oxidative stress, and inflammation and to evaluate endothelial microvesicle (EMV) release, a new reliable biomarker of vascular stress/damage.

METHODS

We studied Liraglutide effects and its plausible molecular mechanisms on monocyte cell adhesion and adhesion molecule expression and membrane exposure in control (C-) human umbilical vein endothelial cells (HUVEC) as well as in HUVEC of women affected by GD exposed in vitro to TNF-α. In the same model, we also investigated Liraglutide effects on EMV release.

RESULTS

In response to TNF-α, endothelial monocyte adhesion and VCAM-1 and ICAM-1 expression and exposure on plasma membrane was greater in GD-HUVEC than C-HUVEC. This was the case also for EMV release. In GD-HUVEC, Liraglutide exposure significantly reduced TNF-α induced endothelial monocyte adhesion as well as VCAM-1 and ICAM-1 expression and exposure on plasma membrane. In the same cells, Liraglutide exposure also reduced MAPK/NF-kB activation, peroxynitrite levels, and EMV release.

CONCLUSIONS

TNF-α induced pro-atherogenic alterations are amplified in endothelial cells chronically exposed to hyperglycemia in vivo. Liraglutide mitigates TNF-α effects and reduces cell stress/damage indicators, such as endothelial microvesicle (EMV) release. These results foster the notion that Liraglutide could exert a protective effect against hyperglycemia and inflammation triggered endothelial dysfunction.

High glucose increases the formation and pro-oxidative activity of endothelial microparticles

AIMS/HYPOTHESIS

Individuals with diabetes exhibit increases in circulating endothelial microparticles (eMPs, also referred to as endothelial microvesicles), which are associated with endothelial dysfunction and a heightened risk of cardiovascular complications. We have shown that eMPs are markers and mediators of vascular injury although their role in diabetes is unclear. We hypothesised that the composition and biological activity of eMPs are altered in response to high glucose exposure. We assessed the effects of high glucose on eMP formation, composition and signalling in cultured HUVECs.

METHODS

eMPs were isolated from the media of HUVECs cultured under conditions of normal glucose (eMP^NG), high glucose (eMP^HG) or osmotic control of L-glucose (eMP^LG). eMP size, concentration and surface charge were assessed by nanoparticle tracking analysis and flow cytometry. eMP protein composition was assessed by liquid chromatography-tandem mass spectrometry, and eMP-mediated effects on coagulation, reactive oxygen species (ROS) production and vessel function were assessed.

RESULTS

Exposure of HUVECs to high glucose for 24 h caused a threefold increase in eMP formation, increased mean particle size (269 ± 18 nm vs 226 ± 11 nm) and decreased surface charge. Compared with eMP^NG or eMP^LG, eMP^HG possessed approximately threefold greater pro-coagulant activity, stimulated HUVEC ROS production to a greater extent (~250% of eMP^NG) and were more potent inhibitors of endothelial-dependent relaxation. Proteomic analysis of eMPs identified 1212 independent proteins of which 68 were exclusively found in eMP^HG. Gene ontology analysis revealed that eMP^HG-exclusive proteins were associated with signalling pathways related to blood coagulation, cell signalling and immune cell activation.

CONCLUSIONS/INTERPRETATION

Our results indicate that elevated glucose is a potent stimulus for eMP formation that also alters their molecular composition leading to increased bioactivity. Such effects may contribute to progressive endothelial injury and subsequent cardiovascular complications in diabetes.

The Usefulness of Platelet-derived Microparticle as Biomarker of Antiplatelet Therapy in Kawasaki Disease

Little is known about platelet dynamics and the effect of antiplatelet therapy in Kawasaki disease (KD). This study sought to define platelet activation dynamics in KD patients by assaying platelet-derived microparticles (PDMPs). We measured plasma PDMPs levels in 46 patients with KD using an enzyme-linked immunosorbent assay (ELISA). Blood samples were collected before, at 2-5 days, and 9-15 days after intravenous immunoglobulin (IVIG) infusion, 2 months and 4-5 months after the onset of KD. We measured PDMP levels in 23 febrile and 10 afebrile control patients. In the acute phase of KD patients, PDMP levels increased significantly after IVIG treatment (12.04 ± 5.58 nmol before IVIG infusion vs. 19.81 ± 13.21 nmol at 2-5 days after IVIG infusion, P = 0.006). PDMP levels were negatively correlated with age and positively correlated with procalcitonin levels in the acute phase of KD. No significant difference was found in PDMP levels between KD patients with and without coronary artery lesion (CAL). Elevated PDMP levels after IVIG therapy significantly decreased below the pre-IVIG level in subacute phase (19.81 ± 13.21 nmol at 2-5 days after IVIG infusion vs. 8.33 ± 2.02 nmol at 9-15 days after IVIG infusion, P < 0.001), and PDMP levels stayed below the pre-IVIG level in the convalescent phase, during which antiplatelet therapy was given. However, PDMP levels rebounded after discontinuing aspirin in 17 patients. In conclusion, enhanced platelet activation was noted before treatment of KD and peaked immediately after IVIG treatment. Recurrent rising of PDMP levels was observed after discontinuing aspirin, although there were no significant differences between the PDMP levels at 2 months after the onset of KD and those at 4-5 months after the onset of the disease.

Effects of Mesenchymal Stem Cell Derivatives on Hematopoiesis and Hematopoietic Stem Cells

Hematopoiesis is a balance among quiescence, self-renewal, proliferation, and differentiation, which is believed to be firmly adjusted through interactions between hematopoietic stem and progenitor cells (HSPCs) with the microenvironment. This microenvironment is derived from a common progenitor of mesenchymal origin and its signals should be capable of regulating the cellular memory of transcriptional situation and lead to an exchange of stem cell genes expression. Mesenchymal stem cells (MSCs) have self-renewal and differentiation capacity into tissues of mesodermal origin, and these cells can support hematopoiesis through release various molecules that play a crucial role in migration, homing, self-renewal, proliferation, and differentiation of HSPCs. Studies on the effects of MSCs on HSPC differentiation can develop modern solutions in the treatment of patients with hematologic disorders for more effective Bone Marrow (BM) transplantation in the near future. However, considerable challenges remain on realization of how paracrine mechanisms of MSCs act on the target tissues, and how to design a therapeutic regimen with various paracrine factors in order to achieve optimal results for tissue conservation and regeneration. The aim of this review is to characterize and consider the related aspects of the ability of MSCs secretome in protection of hematopoiesis.

The roles of non-coding RNAs in cardiac regenerative medicine

The emergence of non-coding RNAs (ncRNAs) has challenged the central dogma of molecular biology that dictates that the decryption of genetic information starts from transcription of DNA to RNA, with subsequent translation into a protein. Large numbers of ncRNAs with biological significance have now been identified, suggesting that ncRNAs are important in their own right and their roles extend far beyond what was originally envisaged. ncRNAs do not only regulate gene expression, but are also involved in chromatin architecture and structural conformation. Several studies have pointed out that ncRNAs participate in heart disease; however, the functions of ncRNAs still remain unclear. ncRNAs are involved in cellular fate, differentiation, proliferation and tissue regeneration, hinting at their potential therapeutic applications. Here, we review the current understanding of both the biological functions and molecular mechanisms of ncRNAs in heart disease and describe some of the ncRNAs that have potential heart regeneration effects.

Microvesicles in vascular homeostasis and diseases. Position Paper of the European Society of Cardiology (ESC) Working Group on Atherosclerosis and Vascular Biology

Microvesicles are members of the family of extracellular vesicles shed from the plasma membrane of activated or apoptotic cells. Microvesicles were initially characterised by their pro-coagulant activity and described as "microparticles". There is mounting evidence revealing a role for microvesicles in intercellular communication, with particular relevance to hemostasis and vascular biology. Coupled with this, the potential of microvesicles as meaningful biomarkers is under intense investigation. This Position Paper will summarise the current knowledge on the mechanisms of formation and composition of microvesicles of endothelial, platelet, red blood cell and leukocyte origin. This paper will also review and discuss the different methods used for their analysis and quantification, will underline the potential biological roles of these vesicles with respect to vascular homeostasis and thrombosis and define important themes for future research.

Role of monocyte tissue factor on patients with non-small cell lung cancer

BACKGROUND

To examine the expression of D-dimer, fibrinogen (FIB), leukocyte, C-reactive protein (CRP) and tissue factor (TF) released from monocyte in non-small cell lung cancer (NSCLC) patients with or without venous thromboembolism (VTE) and analyse the correlation, to explore the possible mechanisms.

METHODS

Seventy-two patients confirmed the diagnosis of lung cancer, among whom 10 with VTE were enrolled into the study from November 2012 to January 2014 in the First Affiliated Hospital of Fujian Medical University and 30 healthy subjects were also enrolled as the control group. Ficoll and Percoll density gradient centrifugation separated of peripheral blood monocyte. Monocyte TF mRNA expression was detected using reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

There were significant differences in different stages of the cancer (P < .05) and no significance among the histopathologic types (P > .05) for the expression of monocyte TF mRNA in NSCLC patients, its expression was significantly higher in cancer with lymph node metastasis than those without lymph node metastasis (P < .01). Meanwhile, in NSCLC patients with VTE, the expression of monocyte TF mRNA was significantly higher than that in patients without VTE (P < .01). Difference of the survival curves between the low monocyte TF mRNA expression and the high monocyte TF mRNA expression was significant (Log-rank x2 = 4.923, P < .05).

CONCLUSIONS

Monocyte TF may be a relevant source of TF-mediated thrombogenicity in NSCLC patients and may be associated with prognosis in NSCLC.