Extracellular vesicles (EVs) are gaining increasing amounts of attention due to their potential use in diagnostics and therapy, but the poor reproducibility of the studies that have been conducted on ...these structures hinders their breakthrough into routine practice. We believe that a better understanding of EVs stability and methods to control their integrity are the key to resolving this issue. In this work, erythrocyte EVs (hbEVs) were isolated by centrifugation from suspensions of human erythrocytes that had been aged in vitro. The isolate was characterised by scanning (SEM) and cryo-transmission electron microscopy (cryo-TEM), flow cytometry (FCM), dynamic/static light scattering (LS), protein electrophoresis, and UV-V spectrometry. The hbEVs were exposed to various conditions (pH (4-10), osmolarity (50-1000 mOsm/L), temperature (15-60 °C), and surfactant Triton X-100 (10-500 μM)). Their stability was evaluated by LS by considering the hydrodynamic radius (
), intensity of scattered light (
), and the shape parameter (
). The morphology of the hbEVs that had been stored in phosphate-buffered saline with citrate (PBS-citrate) at 4 °C remained consistent for more than 6 months. A change in the media properties (50-1000 mOsm/L, pH 4-10) had no significant effect on the
(=100-130 nm). At pH values below 6 and above 8, at temperatures above 45 °C, and in the presence of Triton X-100, hbEVs degradation was indicated by a decrease in
of more than 20%. Due to the simple preparation, homogeneous morphology, and stability of hbEVs under a wide range of conditions, they are considered to be a suitable option for EV reference material.
Correction for 'An EPR study of ampullosporin A, a medium-length peptaibiotic, in bicelles and vesicles' by Marco Bortolus
et al.
,
Phys. Chem. Chem. Phys.
, 2016,
18
, 749-760.
Bacteria contribute to human host (patho)physiology through the production of a myriad of biomolecules enclosed in membrane vesicles bacterial extracellular vesicles (BEVs). Recent research revealed ...that BEVs, as a functional output of bacteria, enter the systemic circulation. Here, we highlight the current state of knowledge on the origin, translocation, distribution, function, and excretion or elimination of systemically circulating BEVs and delineate knowledge gaps. Further investigations on the so far occult stages of BEV entry beyond the walls of epithelial and immune barriers will unmask the role of BEVs in health and disease.
Extracellular vesicles (EVs) are small lipid membrane vesicles that are secreted from almost all kinds of cells into the extracellular space. EVs are widely accepted to be involved in various ...cellular processes; in particular, EVs derived from cancer cells have been reported to play important roles in modifying the tumor microenvironment and promoting tumor progression. In addition, EVs derived from cancer cells encapsulate various kinds of tumor-specific molecules, such as proteins and RNAs, which contribute to cancer malignancy. Therefore, the unveiling of the precise mechanism of intercellular communication via EVs in cancer patients will provide a novel strategy for cancer treatment. Furthermore, a focus on the contents of EVs could promote the use of EVs in body fluids as clinically useful diagnostic and prognostic biomarkers. In this review, we summarize the current research knowledge on EVs as biomarkers and therapeutic targets and discuss their potential clinical applications.
Extracellular vesicles (EVs) are blebs of either plasma membrane or intracellular membranes carrying a cargo of proteins, nucleic acids, and lipids. EVs are produced by eukaryotic cells both under ...physiological and pathological conditions. Genetic and environmental factors (diet, stress, etc.) affecting EV cargo, regulating EV release, and consequences on immunity will be covered. EVs are found in virtually all body fluids such as plasma, saliva, amniotic fluid, and breast milk, suggesting key roles in immune development and function at different life stages from in utero to aging. These will be reviewed here. Under pathological conditions, plasma EV levels are increased and exacerbate immune activation and inflammatory reaction. Sources of EV, cells targeted, and consequences on immune function and disease development will be discussed. Both pathogenic and commensal bacteria release EV, which are classified as outer membrane vesicles when released by Gram-negative bacteria or as membrane vesicles when released by Gram-positive bacteria. Bacteria derived EVs can affect host immunity with pathogenic bacteria derived EVs having pro-inflammatory effects of host immune cells while probiotic derived EVs mostly shape the immune response towards tolerance.
All bacteria produce secreted vesicles that carry out a variety of important biological functions. These extracellular vesicles can improve adaptation and survival by relieving bacterial stress and ...eliminating toxic compounds, as well as by facilitating membrane remodeling and ameliorating inhospitable environments. However, vesicle production comes with a price. It is energetically costly and, in the case of colonizing pathogens, it elicits host immune responses, which reduce bacterial viability. This raises an interesting paradox regarding why bacteria produce vesicles and begs the question as to whether the benefits of producing vesicles outweigh their costs. In this review, we discuss the various advantages and disadvantages associated with Gram‐negative and Gram‐positive bacterial vesicle production and offer perspective on the ultimate score. We also highlight questions needed to advance the field in determining the role for vesicles in bacterial survival, interkingdom communication, and virulence.
Why do bacteria produce vesicles? They facilitate nutrient acquisition, survival, and adaptation, but also elicit antagonistic host responses. Close examination reveals how vesicle production yields a net positive for bacteria.
Bacterial extracellular vesicles (bEVs) are nano-sized, lipid membrane-delimited particles filled with bacteria-derived components. They have important roles in the physiology and pathogenesis of ...bacteria, and in bacteria–bacteria and bacteria–host interactions. Interestingly, recent advances in biotechnology have made it possible to engineer the bEV surface and decorate it with diverse biomolecules and nanoparticles (NPs). bEVs have been the focus of significant interest in a range of biomedical fields and are being evaluated as vaccines, cancer immunotherapy agents, and drug delivery vehicles. However, significant hurdles in terms of their safety, efficacy, and mass production need to be addressed to enable their full clinical potential. Here, we review recent advances and remaining obstacles regarding the use of bEVs in different biomedical applications and discuss paths toward clinical translation.
Bacterial extracellular vesicles (bEVs) are released by Gram-negative and specific Gram-positive bacteria and have a role in bacteria–bacteria and bacteria–host interactions.The functional versatility of bEVs, their nonreplicative nature, intrinsic cell-targeting properties, and ability to overcome natural barriers endow them with promising potential for different biomedical applications.Standardized and efficient separation of bEVs from matrices containing contaminants, such as EVs and lipoproteins, remains a challenge.Techniques for isolating and analyzing bEV subtypes are needed.Both natural and modified bEVs are under development for various biomedical applications, including for vaccination, cancer immunotherapy, and drug delivery, and as antibacterial agents and diagnostics.Clinical use of bEVs to replace, or to combine with, traditional drugs and therapies may improve therapeutic outcomes.
The therapeutic potential of extracellular vesicles from eukaryotes has gained strong interest in recent years. However, research into the therapeutic application of their bacterial counterparts, ...known as bacterial membrane vesicles, is only just beginning to be appreciated. Membrane vesicles (MVs) from both Gram-positive and Gram-negative bacteria offer significant advantages in therapeutic development, including large-scale, cost effective production and ease of molecular manipulation to display foreign antigens. The nanoparticle size of MVs enables their dissemination through numerous tissue types, and their natural immunogenicity and self-adjuvanting capability can be harnessed to induce both cell-mediated and humoral immunity in vaccine design. Moreover, the ability to target MVs to specific tissues through the display of surface receptors raises their potential use as targeted MV-based anti-cancer therapy. This review discusses recent advances in MV research with particular emphasis on exciting new possibilities for the application of MVs in therapeutic design.
In the past decade, cell-to-cell communication mediated by exosomes has attracted growing attention from biomedical scientists and physicians, leading to several recent publications in top-tier ...journals. Exosomes are generally defined as secreted membrane vesicles, or extracellular vesicles (EVs), corresponding to the intraluminal vesicles of late endosomal compartments, which are secreted upon fusion of multi-vesicular endosomes with the cell's plasma membrane. Cells, however, were shown to release other types of EVs, for instance, by direct budding off their plasma membrane. Some of these EVs share with exosomes major biophysical and biochemical characteristics, such as size, density and membrane orientation, which impose difficulties in their efficient separation. Despite frequent claims in the literature, whether exosomes really display more important patho/physiological functions, or are endowed with higher potential as diagnostic or therapeutic tools than other EVs, is not yet convincingly demonstrated. In this opinion article, we describe reasons for this lack of precision knowledge in the current stage of the EV field, we review recently described approaches to overcome these caveats, and we propose ways to improve our knowledge on the respective functions of distinct EVs, which will be crucial for future development of well-designed EV-based clinical applications.
This article is part of the discussion meeting issue ‘Extracellular vesicles and the tumour microenvironment’.
α-Synuclein (αS) is a presynaptic disordered protein whose aberrant aggregation is associated with Parkinson's disease. The functional role of αS is still debated, although it has been involved in ...the regulation of neurotransmitter release via the interaction with synaptic vesicles (SVs). We report here a detailed characterisation of the conformational properties of αS bound to the inner and outer leaflets of the presynaptic plasma membrane (PM), using small unilamellar vesicles. Our results suggest that αS preferentially binds the inner PM leaflet. On the basis of these studies we characterise in vitro a mechanism by which αS stabilises, in a concentration-dependent manner, the docking of SVs on the PM by establishing a dynamic link between the two membranes. The study then provides evidence that changes in the lipid composition of the PM, typically associated with neurodegenerative diseases, alter the modes of binding of αS, specifically in a segment of the sequence overlapping with the non-amyloid component region. Taken together, these results reveal how lipid composition modulates the interaction of αS with the PM and underlie its functional and pathological behaviours in vitro.
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