Explore the vast range of titles available.

The terms microparticles (MPs) and microvesicles (MVs) refer to large extracellular vesicles (EVs) generated from a broad spectrum of cells upon its activation or death by apoptosis. The unique surface antigens of MPs/MVs allow for the identification of their cellular origin as well as its functional characterization. Two basic aspects of MP/MV functions in physiology and pathological conditions are widely considered. Firstly, it has become evident that large EVs have strong procoagulant properties. Secondly, experimental and clinical studies have shown that MPs/MVs play a crucial role in the pathophysiology of inflammation-associated disorders. A cardinal feature of these disorders is an enhanced generation of platelets-, endothelial-, and leukocyte-derived EVs. Nevertheless, anti-inflammatory effects of miscellaneous EV types have also been described, which provided important new insights into the large EV-inflammation axis. Advances in understanding the biology of MPs/MVs have led to the preparation of this review article aimed at discussing the association between large EVs and inflammation, depending on their cellular origin.

Increasing evidence indicates that the ability of cancer cells to convey biological information to recipient cells within the tumor microenvironment (TME) is crucial for tumor progression. Microvesicles (MVs) are heterogenous vesicles formed by budding of the cellular membrane, which are secreted in larger amounts by cancer cells than normal cells. Recently, several reports have also disclosed that MVs function as important mediators of intercellular communication between cancerous and stromal cells within the TME, orchestrating complex pathophysiological processes. Chemokines are a family of small inflammatory cytokines that are able to induce chemotaxis in responsive cells. MVs which selective incorporate chemokines as their molecular cargos may play important regulatory roles in oncogenic processes including tumor proliferation, apoptosis, angiogenesis, metastasis, chemoresistance and immunomodulation, et al. Therefore, it is important to explore the association of MVs and chemokines in TME, identify the potential prognostic marker of tumor, and develop more effective treatment strategies. Here we review the relevant literature regarding the role of MVs and chemokines in TME.

BackgroundAtherosclerotic plaque formation is the underlying cause of heart attack and stroke. Macrophages play a key role in plaque progression. Neutrophils are rarely detected in plaques but have been shown to play an integral role in plaque development. We have previously shown that microvesicles released from stimulated neutrophils are present in plaques and enhance plaque formation. Neutrophil microvesicles (NMV) have been found to modulate macrophage activity in atherosclerosis and are known to contain microRNA that can influence macrophage behaviour. We hypothesise that NMV can interact with macrophages within atherosclerotic plaques and alter macrophage phenotype and function.MethodsTo determine whether NMV can cross the endothelium, human coronary artery endothelial cells (HCAEC) were cultured ± TNF on transwell inserts. NMV were stained with PKH lipophilic membrane dye and added to the upper compartment of the transwells at ratios of 1:10, 1:50, and 1:100 HCAEC: NMV. After 24h NMV in the basal chamber were visualised using fluorescent microscopy and quantified using Fiji. To investigate NMV internalisation by macrophages, M0 human monocyte-derived macrophages (HMDM) were treated at a ratio of 1:100 HMDM:PKH stained NMV for periods of 24, 6 and 1h. Following treatment, NMV internalisation was quantified by flow cytometry and visualised using confocal microscopy. Trypan blue was used to quench surface fluorescence and distinguish between adherent and internalised NMV. Modulation of macrophage polarisation by NMV was assessed by RT- qPCR analysis of CD68, CD86, MRC1 and CD163 expression after 24h.ResultsNMV were able to cross the endothelium in a dose-dependent manner. NMV also interacted with both stimulated and unstimulated HCAECs. NMV interaction with HMDM occurred rapidly with approximately 10% HMDM being identified as PKH+ve after 1h. Internalization of NMVs by HMDMs increased over time with approximately 64% of PKH+ve cells containing NMV after 24h. However, incubation of HMDM with NMVs did not result in any significant changes in polarisation marker expression after 24h.ConclusionsNMV can cross the endothelial monolayer and interact with macrophages. They are internalised by macrophages but are not able to induce changes in polarisation in the absence of other polarising stimuli. Further investigation is underway to elucidate the mechanisms of NMV internalisation and determine whether NMV can act synergistically with cytokines present in the plaque to influence macrophage polarisation.Conflict of InterestNone

Introduction Atherosclerosis is the major underlying cause of heart attack and stroke and, as such, understanding the underlying pathological mechanisms of the disease remains a priority. Whilst neutrophils are the most abundant circulating leukocyte, they are rarely detected within developing plaques. Neutrophil microvesicles (NMVs), large (>0.1µm) extracellular vesicles derived from the plasma membrane, were shown to increase miR-155 in endothelial cells (ECs) at atheroprone sites. This led to exacerbation of plaque formation in a mouse model of atherosclerosis. We hypothesise that NMVs contain other microRNA (miRNA) that may influence atherosclerosis initiation and progression.MethodsNMV were isolated from human peripheral blood neutrophils that were stimulated with 10 ng/mL native (n)LDL, 10 ng/mL oxidised (ox)LDL, or PBS only (unstimulated control). Small RNAs were isolated from NMV using miRNeasy mini kit (Qiagen, Germany) and quantity and quality of isolated RNA determined using NanoPhotometer® N60 spectrophotometer (Geneflow, UK) and a 2100 Bioanalyser (Agilent, UK). Small RNA sequencing analysis was performed using Illumina sequencing platform by Novogen, UK. Sequencing data was processed to obtain the clean reads that aligned to the human reference genome. Data was further processed and visualised using R software.Results757 miRNAs were detected in NMVs. Of these, 527 miRNAs were expressed in all NMV groups, 55 uniquely expressed in NMVs from n/oxLDL stimulated neutrophils and 36 only in unstimulated control NMVs. The most abundant miRNA in all samples was miR-148a-3p, a miRNA previously shown to enhance plaque formation. High levels of miR-155 were also detected in all samples.ConclusionNMVs have been found to contain a high abundance of miRNAs, with some expression dependent on the stimulus used for induction of MV release. Target and pathway analysis of these data are ongoing. miRNA previously shown to play a role in plaque formation were among the most highly abundant within NMV suggesting that NMV delivery of miRNA to atherosclerotic plaques may play an important role in exacerbating plaque formation.Conflict of InterestThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this poster.

The release of extracellular vesicles (EVs), including exosomes and microvesicles, is a phenomenon shared by many cell types as a means of communicating with other cells and also potentially removing cell contents. The cargo of EVs includes the proteins, lipids, nucleic acids, and membrane receptors of the cells from which they originate. EVs released into the extracellular space can enter body fluids and potentially reach distant tissues. Once taken up by neighboring and/or distal cells, EVs can transfer functional cargo that may alter the status of recipient cells, thereby contributing to both physiological and pathological processes. In this article, we will focus on EV composition, mechanisms of uptake, and their biological effects on recipient cells. We will also discuss established and recently developed methods used to study EVs, including isolation, quantification, labeling and imaging protocols, as well as RNA analysis.

Extracellular vesicles (EVs), including exosomes, microvesicles, and apoptotic bodies, are nanosized membrane vesicles derived from most cell types. Carrying diverse biomolecules from their parent cells, EVs are important mediators of intercellular communication and thus play significant roles in physiological and pathological processes. Owing to their natural biogenesis process, EVs are generated with high biocompatibility, enhanced stability, and limited immunogenicity, which provide multiple advantages as drug delivery systems (DDSs) over traditional synthetic delivery vehicles. EVs have been reported to be used for the delivery of siRNAs, miRNAs, protein, small molecule drugs, nanoparticles, and CRISPR/Cas9 in the treatment of various diseases. As a natural drug delivery vectors, EVs can penetrate into the tissues and be bioengineered to enhance the targetability. Although EVs' characteristics make them ideal for drug delivery, EV-based drug delivery remains challenging, due to lack of standardized isolation and purification methods, limited drug loading efficiency, and insufficient clinical grade production. In this review, we summarized the current knowledge on the application of EVs as DDS from the perspective of different cell origin and weighted the advantages and bottlenecks of EV-based DDS.

The many functions of extracellular vesicles (EVs) like exosomes and microvesicles released from healthy cells have been well characterized, particularly in relation to their roles in immune modulation. Apoptotic bodies, a major class of EV released as a product of apoptotic cell disassembly, and other types of EVs released from dying cells are also becoming recognized as key players in this emerging field. There is now increasing evidence to suggest that EVs produced during apoptosis have important immune regulatory roles, a concept relevant across different disease settings including autoimmunity, cancer, and infection. Therefore, this review focuses on how the formation of EVs during apoptosis could be a key mechanism of immune modulation by dying cells.

Exosomes are nanosized membrane vesicles released by fusion of an organelle of the endocytic pathway, the multivesicular body, with the plasma membrane. This process was discovered more than 30 years ago, and during these years, exosomes have gone from being considered as cellular waste disposal to mediate a novel mechanism of cell-to-cell communication. The exponential interest in exosomes experienced during recent years is due to their important roles in health and disease and to their potential clinical application in therapy and diagnosis. However, important aspects of the biology of exosomes remain unknown. To explore the use of exosomes in the clinic, it is essential that the basic molecular mechanisms behind the transport and function of these vesicles are better understood. We have here summarized what is presently known about how exosomes are formed and released by cells. Moreover, other cellular processes related to exosome biogenesis and release, such as autophagy and lysosomal exocytosis are presented. Finally, methodological aspects related to exosome release studies are discussed.

Extracellular vesicles (EVs) are membranous vesicles secreted by both prokaryotic and eukaryotic cells and play a vital role in intercellular communication. EVs are classified into several subtypes based on their origin, physical characteristics, and biomolecular makeup. Exosomes, a subtype of EVs, are released by the fusion of multivesicular bodies (MVB) with the plasma membrane of the cell. Several methods have been described in literature to isolate exosomes from biofluids including blood, urine, milk, and cell culture media, among others. While differential ultracentrifugation (dUC) has been widely used to isolate exosomes, other techniques including ultrafiltration, precipitating agents such as poly-ethylene glycol (PEG), immunoaffinity capture, microfluidics, and size-exclusion chromatography (SEC) have emerged as credible alternatives with pros and cons associated with each. In this review, we provide a summary of commonly used exosomal isolation techniques with a focus on SEC as an ideal methodology. We evaluate the efficacy of SEC to isolate exosomes from an array of biological fluids, with a particular focus on its application to adipose tissue-derived exosomes. We argue that exosomes isolated via SEC are relatively pure and functional, and that this methodology is reproducible, scalable, inexpensive, and does not require specialized equipment or user expertise. However, it must be noted that while SEC is a good candidate method to isolate exosomes, direct comparative studies are required to support this conclusion.