Infrared spectroscopic characterization of monocytic microvesicles (microparticles) released upon lipopolysaccharide stimulation

Fluorescent, phosphorescent, magnetic resonance contrast and radioactive tracer labelling of extracellular vesicles

This review focusses on the significance of fluorescent, phosphorescent labelling and tracking of extracellular vesicles (EVs) for unravelling their biology, pathophysiology, and potential diagnostic and therapeutic uses. Various labeling strategies, such as lipid membrane, surface protein, luminal, nucleic acid, radionuclide, quantum dot labels, and metal complex-based stains, are evaluated for visualizing and characterizing EVs. Direct labelling with fluorescent lipophilic dyes is simple but generally lacks specificity, while surface protein labelling offers selectivity but may affect EV-cell interactions. Luminal and nucleic acid labelling strategies have their own advantages and challenges. Each labelling approach has strengths and weaknesses, which require a suitable probe and technique based on research goals, but new tetranuclear polypyridylruthenium(II) complexes as phosphorescent probes have strong phosphorescence, selective staining, and stability. Future research should prioritize the design of novel fluorescent probes and labelling platforms that can significantly enhance the efficiency, accuracy, and specificity of EV labeling, while preserving their composition and functionality. It is crucial to reduce false positive signals and explore the potential of multimodal imaging techniques to gain comprehensive insights into EVs.

Advancements in Mid-Infrared spectroscopy of extracellular vesicles

Extracellular vesicles (EVs) are lipid vesicles secreted by all cells into the extracellular space and act as nanosized biological messengers among cells. They carry a specific molecular cargo, composed of lipids, proteins, nucleic acids, and carbohydrates, which reflects the state of their parent cells. Due to their remarkable structural and compositional heterogeneity, characterizing EVs, particularly from a biochemical perspective, presents complex challenges. In this context, mid-infrared (IR) spectroscopy is emerging as a valuable tool, providing researchers with a comprehensive and label-free spectral fingerprint of EVs in terms of their specific molecular content. This review aims to provide an up-to-date critical overview of the major advancements in mid-IR spectroscopy of extracellular vesicles, encompassing both fundamental and applied research achievements. We also systematically emphasize the new possibilities offered by the integration of emerging cutting-edge IR technologies, such as tip-enhanced and surface-enhanced spectroscopy approaches, along with the growing use of machine learning for data analysis and spectral interpretation. Additionally, to assist researchers in navigating this intricate subject, our manuscript includes a wide and detailed collection of the spectral peaks that have been assigned to EV molecular constituents up to now in the literature.

Perillyl alcohol modulates activation, permeability and integrity of human brain endothelial cells induced by Plasmodium falciparum

BACKGROUND

Cerebral malaria (CM) is a severe immunovasculopathy caused for Plasmodium falciparum infection, which is characterised by the sequestration of parasitised red blood cells (pRBCs) in brain microvessels. Previous studies have shown that some terpenes, such as perillyl alcohol (POH), exhibit a marked efficacy in preventing cerebrovascular inflammation, breakdown of the brain-blood barrier (BBB) and brain leucocyte accumulation in experimental CM models.

OBJECTIVE

To analyse the effects of POH on the endothelium using human brain endothelial cell (HBEC) monolayers co-cultured with pRBCs.

METHODOLOGY

The loss of tight junction proteins (TJPs) and features of endothelial activation, such as ICAM-1 and VCAM-1 expression were evaluated by quantitative immunofluorescence. Microvesicle (MV) release by HBEC upon stimulation by P. falciparum was evaluated by flow cytometry. Finally, the capacity of POH to revert P. falciparum-induced HBEC monolayer permeability was examined by monitoring trans-endothelial electrical resistance (TEER).

FINDINGS

POH significantly prevented pRBCs-induced endothelial adhesion molecule (ICAM-1, VCAM-1) upregulation and MV release by HBEC, improved their trans-endothelial resistance, and restored their distribution of TJPs such as VE-cadherin, Occludin, and JAM-A.

CONCLUSIONS

POH is a potent monoterpene that is efficient in preventing P. falciparum-pRBCs-induced changes in HBEC, namely their activation, increased permeability and alterations of integrity, all parameters of relevance to CM pathogenesis.

Antenna-enhanced mid-infrared detection of extracellular vesicles derived from human cancer cell cultures

BACKGROUND

Extracellular Vesicles (EVs) are sub-micrometer lipid-bound particles released by most cell types. They are considered a promising source of cancer biomarkers for liquid biopsy and personalized medicine due to their specific molecular cargo, which provides biochemical information on the state of parent cells. Despite this potential, EVs translation process in the diagnostic practice is still at its birth, and the development of novel medical devices for their detection and characterization is highly required.

RESULTS

In this study, we demonstrate mid-infrared plasmonic nanoantenna arrays designed to detect, in the liquid and dry phase, the specific vibrational absorption signal of EVs simultaneously with the unspecific refractive index sensing signal. For this purpose, EVs are immobilized on the gold nanoantenna surface by immunocapture, allowing us to select specific EV sub-populations and get rid of contaminants. A wet sample-handling technique relying on hydrophobicity contrast enables effortless reflectance measurements with a Fourier-transform infrared (FTIR) spectro-microscope in the wavelength range between 10 and 3 µm. In a proof-of-principle experiment carried out on EVs released from human colorectal adenocarcinoma (CRC) cells, the protein absorption bands (amide-I and amide-II between 5.9 and 6.4 µm) increase sharply within minutes when the EV solution is introduced in the fluidic chamber, indicating sensitivity to the EV proteins. A refractive index sensing curve is simultaneously provided by our sensor in the form of the redshift of a sharp spectral edge at wavelengths around 5 µm, where no vibrational absorption of organic molecules takes place: this permits to extract of the dynamics of EV capture by antibodies from the overall molecular layer deposition dynamics, which is typically measured by commercial surface plasmon resonance sensors. Additionally, the described metasurface is exploited to compare the spectral response of EVs derived from cancer cells with increasing invasiveness and metastatic potential, suggesting that the average secondary structure content in EVs can be correlated with cell malignancy.

CONCLUSIONS

Thanks to the high protein sensitivity and the possibility to work with small sample volumes-two key features for ultrasensitive detection of extracellular vesicles- our lab-on-chip can positively impact the development of novel laboratory medicine methods for the molecular characterization of EVs.

Microfluidics for detection of exosomes and microRNAs in cancer: State of the art

Exosomes are small extracellular vesicles with sizes ranging from 30-150 nanometers that contain proteins, lipids, mRNAs, microRNAs, and double-stranded DNA derived from the cells of origin. Exosomes can be taken up by target cells, acting as a means of cell-to-cell communication. The discovery of these vesicles in body fluids and their participation in cell communication has led to major breakthroughs in diagnosis, prognosis, and treatment of several conditions (e.g., cancer). However, conventional isolation and evaluation of exosomes and their microRNA content suffers from high cost, lengthy processes, difficult standardization, low purity, and poor yield. The emergence of microfluidics devices with increased efficiency in sieving, trapping, and immunological separation of small volumes could provide improved detection and monitoring of exosomes involved in cancer. Microfluidics techniques hold promise for advances in development of diagnostic and prognostic devices. This review covers ongoing research on microfluidics devices for detection of microRNAs and exosomes as biomarkers and their translation to point-of-care and clinical applications.

Machine Learning-Assisted FTIR Analysis of Circulating Extracellular Vesicles for Cancer Liquid Biopsy

Extracellular vesicles (EVs) are abundantly released into the systemic circulation, where they show remarkable stability and harbor molecular constituents that provide biochemical information about their cells of origin. Due to this characteristic, EVs are attracting increasing attention as a source of circulating biomarkers for cancer liquid biopsy and personalized medicine. Despite this potential, none of the discovered biomarkers has entered the clinical practice so far, and novel approaches for the label-free characterization of EVs are highly demanded. In this regard, Fourier Transform Infrared Spectroscopy (FTIR) has great potential as it provides a quick, reproducible, and informative biomolecular fingerprint of EVs. In this pilot study, we investigated, for the first time in the literature, the capability of FTIR spectroscopy to distinguish between EVs extracted from sera of cancer patients and controls based on their mid-IR spectral response. For this purpose, EV-enriched suspensions were obtained from the serum of patients diagnosed with Hepatocellular Carcinoma (HCC) of nonviral origin and noncancer subjects. Our data point out the presence of statistically significant differences in the integrated intensities of major mid-IR absorption bands, including the carbohydrate and nucleic acids band, the protein amide I and II bands, and the lipid CH stretching band. Additionally, we used Principal Component Analysis combined with Linear Discriminant Analysis (PCA-LDA) for the automated classification of spectral data according to the shape of specific mid-IR spectral signatures. The diagnostic performances of the proposed spectral biomarkers, alone and combined, were evaluated using multivariate logistic regression followed by a Receiving Operator Curve analysis, obtaining large Areas Under the Curve (AUC = 0.91, 95% CI 0.81–1.0). Very interestingly, our analyses suggest that the discussed spectral biomarkers can outperform the classification ability of two widely used circulating HCC markers measured on the same groups of subjects, namely alpha-fetoprotein (AFP), and protein induced by the absence of vitamin K or antagonist-II (PIVKA-II).

Recent advances in optical label-free characterization of extracellular vesicles

Extracellular vesicles (EVs) are complex biological nanoparticles endogenously secreted by all eukaryotic cells. EVs carry a specific molecular cargo of proteins, lipids, and nucleic acids derived from cells of origin and play a significant role in the physiology and pathology of cells, organs, and organisms. Upon release, they may be found in different body fluids that can be easily accessed via noninvasive methodologies. Due to the unique information encoded in their molecular cargo, they may reflect the state of the parent cell and therefore EVs are recognized as a rich source of biomarkers for early diagnostics involving liquid biopsy. However, body fluids contain a mixture of EVs released by different types of healthy and diseased cells, making the detection of the EVs of interest very challenging. Recent research efforts have been focused on the detection and characterization of diagnostically relevant subpopulations of EVs, with emphasis on label-free methods that simplify sample preparation and are free of interfering signals. Therefore, in this paper, we review the recent progress of the label-free optical methods employed for the detection, counting, and morphological and chemical characterization of EVs. We will first briefly discuss the biology and functions of EVs, and then introduce different optical label-free techniques for rapid, precise, and nondestructive characterization of EVs such as nanoparticle tracking analysis, dynamic light scattering, atomic force microscopy, surface plasmon resonance spectroscopy, Raman spectroscopy, and SERS spectroscopy. In the end, we will discuss their applications in the detection of neurodegenerative diseases and cancer and provide an outlook on the future impact and challenges of these technologies to the field of liquid biopsy via EVs.

Storage conditions determine the characteristics of red blood cell derived extracellular vesicles

Extracellular vesicles (EVs) are released during the storage of red blood cell (RBC) concentrates and might play adverse or beneficial roles throughout the utilization of blood products (transfusion). Knowledge of EV release associated factors and mechanism amends blood product management. In the present work the impact of storage time and medium (blood preserving additive vs isotonic phosphate buffer) on the composition, size, and concentration of EVs was studied using attenuated total reflection infrared (ATR-IR) spectroscopy, microfluidic resistive pulse sensing (MRPS) and freeze-fraction combined transmission electron micrography (FF-TEM). The spectroscopic protein-to-lipid ratio based on amide and the C-H stretching band intensity ratio indicated the formation of various vesicle subpopulations depending on storage conditions. After short storage, nanoparticles with high relative protein content were detected. Spectral analysis also suggested differences in lipid and protein composition, too. The fingerprint region (from 1300 to 1000 cm^-1) of the IR spectra furnishes additional information about the biomolecular composition of RBC-derived EVs (REVs) such as adenosine triphosphate (ATP), lactose, glucose, and oxidized hemoglobin. The difference between the vesicle subpopulations reveals the complexity of the REV formation mechanism. IR spectroscopy, as a quick, cost-effective, and label-free technique provides valuable novel biochemical insight and might be used complementary to traditional omics approaches on EVs.

Extracellular vesicles: Potential impact on cardiovascular diseases

Extracellular vesicles (EVs) have received considerable attention in biological and clinical research due to their ability to mediate cell-to-cell communication. Based on their size and secretory origin, EVs are categorized as exosomes, microvesicles, and apoptotic bodies. Increasing number of studies highlight the contribution of EVs in the regulation of a wide range of normal cellular physiological processes, including waste scavenging, cellular stress reduction, intercellular communication, immune regulation, and cellular homeostasis modulation. Altered circulating EV level, expression pattern, or content in plasma of patients with cardiovascular disease (CVD) may serve as diagnostic and prognostic biomarkers in diverse cardiovascular pathologies. Due to their inherent characteristics and physiological functions, EVs, in turn, have become potential candidates as therapeutic agents. In this review, we discuss the evolving understanding of the role of EVs in CVD, summarize the current knowledge of EV-mediated regulatory mechanisms, and highlight potential strategies for the diagnosis and therapy of CVD. We also attempt to look into the future that may advance our understanding of the role of EVs in the pathogenesis of CVD and provide novel insights into the field of translational medicine.

New Multiscale Characterization Methodology for Effective Determination of Isolation-Structure-Function Relationship of Extracellular Vesicles

Extracellular vesicles (EVs) have been lauded as next-generation medicines, but very few EV-based therapeutics have progressed to clinical use. Limited clinical translation is largely due to technical barriers that hamper our ability to mass produce EVs, i.e., to isolate, purify, and characterize them effectively. Technical limitations in comprehensive characterization of EVs lead to unpredicted biological effects of EVs. Here, using a range of optical and non-optical techniques, we showed that the differences in molecular composition of EVs isolated using two isolation methods correlated with the differences in their biological function. Our results demonstrated that the isolation method determines the composition of isolated EVs at single and sub-population levels. Besides the composition, we measured for the first time the dry mass and predicted sedimentation of EVs. These parameters were likely to contribute to the biological and functional effects of EVs on single cell and cell cultures. We anticipate that our new multiscale characterization approach, which goes beyond traditional experimental methodology, will support fundamental understanding of EVs as well as elucidate the functional effects of EVs in in vitro and in vivo studies. Our findings and methodology will be pivotal for developing optimal isolation methods and establishing EVs as mainstream therapeutics and diagnostics. This innovative approach is applicable to a wide range of sectors including biopharma and biotechnology as well as to regulatory agencies.

Recent Advances in the Label-Free Characterization of Exosomes for Cancer Liquid Biopsy: From Scattering and Spectroscopy to Nanoindentation and Nanodevices

Exosomes (EXOs) are nano-sized vesicles secreted by most cell types. They are abundant in bio-fluids and harbor specific molecular constituents from their parental cells. Due to these characteristics, EXOs have a great potential in cancer diagnostics for liquid biopsy and personalized medicine. Despite this unique potential, EXOs are not yet widely applied in clinical settings, with two main factors hindering their translational process in diagnostics. Firstly, conventional extraction methods are time-consuming, require large sample volumes and expensive equipment, and often do not provide high-purity samples. Secondly, characterization methods have some limitations, because they are often qualitative, need extensive labeling or complex sampling procedures that can induce artifacts. In this context, novel label-free approaches are rapidly emerging, and are holding potential to revolutionize EXO diagnostics. These methods include the use of nanodevices for EXO purification, and vibrational spectroscopies, scattering, and nanoindentation for characterization. In this progress report, we summarize recent key advances in label-free techniques for EXO purification and characterization. We point out that these methods contribute to reducing costs and processing times, provide complementary information compared to the conventional characterization techniques, and enhance flexibility, thus favoring the discovery of novel and unexplored EXO-based biomarkers. In this process, the impact of nanotechnology is systematically highlighted, showing how the effectiveness of these techniques can be enhanced using nanomaterials, such as plasmonic nanoparticles and nanostructured surfaces, which enable the exploitation of advanced physical phenomena occurring at the nanoscale level.

Extracellular-Vesicle-Based Coatings Enhance Bioactivity of Titanium Implants-SurfEV

Extracellular vesicles (EVs) are nanoparticles released by cells that contain a multitude of biomolecules, which act synergistically to signal multiple cell types. EVs are ideal candidates for promoting tissue growth and regeneration. The tissue regenerative potential of EVs raises the tantalizing possibility that immobilizing EVs on implant surfaces could potentially generate highly bioactive and cell-instructive surfaces that would enhance implant integration into the body. Such surfaces could address a critical limitation of current implants, which do not promote bone tissue formation or bond bone. Here, we developed bioactive titanium surface coatings (SurfEV) using two types of EVs: secreted by decidual mesenchymal stem cells (DEVs) and isolated from fermented papaya fluid (PEVs). For each EV type, we determined the size, morphology, and molecular composition. High concentrations of DEVs enhanced cell proliferation, wound closure, and migration distance of osteoblasts. In contrast, the cell proliferation and wound closure decreased with increasing concentration of PEVs. DEVs enhanced Ca/P deposition on the titanium surface, which suggests improvement in bone bonding ability of the implant (i.e., osteointegration). EVs also increased production of Ca and P by osteoblasts and promoted the deposition of mineral phase, which suggests EVs play key roles in cell mineralization. We also found that DEVs stimulated the secretion of secondary EVs observed by the presence of protruding structures on the cell membrane. We concluded that, by functionalizing implant surfaces with specialized EVs, we will be able to enhance implant osteointegration by improving hydroxyapatite formation directly at the surface and potentially circumvent aseptic loosening of implants.

Comparative Analysis of Platelet-Derived Extracellular Vesicles Using Flow Cytometry and Nanoparticle Tracking Analysis

Growing interest in extracellular vesicles (EVs) has prompted the advancements of protocols for improved EV characterization. As a high-throughput, multi-parameter, and single particle technique, flow cytometry is widely used for EV characterization. The comparison of data on EV concentration, however, is hindered by the lack of standardization between different protocols and instruments. Here, we quantified EV counts of platelet-derived EVs, using two flow cytometers (Gallios and CytoFLEX LX) and nanoparticle tracking analysis (NTA). Phosphatidylserine-exposing EVs were identified by labelling with lactadherin (LA). Calibration with silica-based fluorescent beads showed detection limits of 300 nm and 150 nm for Gallios and CytoFLEX LX, respectively. Accordingly, CytoFLEX LX yielded 40-fold higher EV counts and 13-fold higher counts of LA⁺CD41⁺ EVs compared to Gallios. NTA in fluorescence mode (F-NTA) demonstrated that only 9.5% of all vesicles detected in scatter mode exposed phosphatidylserine, resulting in good agreement of LA⁺ EVs for CytoFLEX LX and F-NTA. Since certain functional characteristics, such as the exposure of pro-coagulant phosphatidylserine, are not equally displayed across the entire EV size range, our study highlights the necessity of indicating the size range of EVs detected with a given approach along with the EV concentration to support the comparability between different studies.

Positively charged gold-silver nanostar enabled molecular characterization of cancer associated extracellular vesicles

Direct surface-enhanced Raman scattering (SERS) has contributed to characterizing extracellular vesicles (EVs) by providing molecular signatures. However, little work has been carried out to understand the heterogeneity of EVs created by different methods or from different biological sources. Herein, we pioneered the use of positively charged gold-silver nanostars to explore the SERS profiles of different EVs. The physical features of EVs from cancer cells including the size, concentration, morphology and surface potential have been characterized via nanoparticle tracking analysis, transmission electron microscopy and zeta potential analysis. The results show that negatively charged EVs are attracted to positively charged gold-silver nanostar surfaces via electrostatic forces resulting in SERS spectra showing characteristic vibrational modes of the different components of EVs (i.e. proteins, lipids and nucleic acids). SERS data were complemented by other spectroscopic techniques including atomic force microscopy-infrared spectroscopy, UV-visible absorbance spectroscopy and fluorescence spectroscopy providing a more complete molecular picture of EVs. SERS signatures of EVs from different origins, batches, and isolation approaches were compared and analyzed. A statistical method (principal component analysis-linear discriminant analysis) was utilized to differentiate EV subtypes. Consequently, a desirable discrimination outcome for blind samples was obtained. This study provides novel insights to deepen our understanding of EV heterogeneity.

Fourier Transform Infrared Spectroscopy as a useful tool for the automated classification of cancer cell-derived exosomes obtained under different culture conditions

Exosomes possess great potential as cancer biomarkers in personalized medicine due to their easy accessibility and capability of representing their parental cells. To boost the translational process of exosomes in diagnostics, the development of novel and effective strategies for their label-free and automated characterization is highly desirable. In this context, Fourier Transform Infrared Spectroscopy (FTIR) has great potential as it provides direct access to specific biomolecular bands that give compositional information on exosomes in terms of their protein, lipid and genetic content. Here, we used FTIR spectroscopy in the mid-Infrared (mid-IR) range to study exosomes released from human colorectal adenocarcinoma HT-29 cancer cells cultured in different media. To this purpose, cells were studied in well-fed condition of growth, with 10% of exosome-depleted FBS (EVd-FBS), and under serum starvation with 0.5% EVd-FBS. Our data show the presence of statistically significant differences in the shape of the Amide I and II bands in the two conditions. Based on these differences, we showed the possibility to automatically classify cancer cell-derived exosomes using Principal Component Analysis combined with Linear Discriminant Analysis (PCA-LDA); we tested the effectiveness of the classifier with a cross-validation approach, obtaining very high accuracy, precision, and recall. Aside from classification purposes, our FTIR data provide hints on the underlying cellular mechanisms responsible for the compositional differences in exosomes, suggesting a possible role of starvation-induced autophagy.

Host- and Microbiota-Derived Extracellular Vesicles, Immune Function, and Disease Development

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.

Extracellular vesicles and microvascular pathology: Decoding the active dialogue

Extracellular vesicles (EV) are a heterogeneous collection of membrane-surrounded structures released from all studied cells, under both physiological and pathological conditions. These nano-size vesicles carry complex cargoes including different classes of proteins, lipids and nucleic acids and are known to act as a communication and signalling vesicles in various cellular process. In addition to their role in development and progression of pathological disorders which make them potentially great biomarkers, EV have beneficial effects, as they take part in homeostasis. In this review we have analysed the evidence for the role of microvesicles and exosomes secreted from other cells on microvascular endothelium (EV uptake) as well as the role of endothelial-derived vesicles on their neighbouring and distant cells (EV release).

None of us is the same as all of us: resolving the heterogeneity of extracellular vesicles using single-vesicle, nanoscale characterization with resonance enhanced atomic force microscope infrared spectroscopy (AFM-IR)

Extracellular vesicles (EVs) are highly specialized, nanoscale messengers that deliver biological signals and in doing so mediate intercellular communication. Increasing evidence shows that within populations of EVs, important properties including morphology, membrane composition, and content vary substantially. This heterogeneity arises in response to the nature, state, and environmental conditions of the cell source. However, currently there are no effective approaches, which unequivocally discriminate differences between individual EVs, which critically hampers progress in this emerging scientific area. Measuring EV heterogeneity is paramount to our understanding of how EVs influence the physiological and pathological functions of their target cells. Moreover, understanding EV heterogeneity is essential for their application as diagnostics and therapeutics. We propose an innovative approach using resonance enhanced atomic force microscope infrared spectroscopy (AFM-IR) to identify the nanoscale structural composition of EVs, as demonstrated and validated using EVs derived from two types of placenta stem cells. The particular strength of this approach is that it is a label-free and ultra-high sensitivity technique that has the power to measure individual EV heterogeneity. New insights gained by this method into EV heterogeneity will have a profound impact not only on our basic understanding of EV biology but also on disease diagnostics and the emerging area of EV-therapies.

Extracellular vesicles and their content in bioactive lipid mediators: more than a sack of microRNA

Extracellular vesicles (EVs), such as exosomes and microvesicles, are small membrane-bound vesicles released by cells under various conditions. In a multitude of physiological and pathological conditions, EVs contribute to intercellular communication by facilitating exchange of material between cells. Rapidly growing interest is aimed at better understanding EV function and their use as biomarkers. The vast EV cargo includes cytokines, growth factors, organelles, nucleic acids (messenger and micro RNA), and transcription factors. A large proportion of research dedicated to EVs is focused on their microRNA cargo; however, much less is known about other EV constituents, in particular, eicosanoids. These potent bioactive lipid mediators, derived from arachidonic acid, are shuttled in EVs along with the enzymes in charge of their synthesis. In the extracellular milieu, EVs also interact with secreted phospholipases to generate eicosanoids, which then regulate the transfer of cargo into a cellular recipient. Eicosanoids are useful as biomarkers and contribute to a variety of biological functions, including modulation of distal immune responses. Here, we review the reported roles of eicosanoids conveyed by EVs and describe their potential as biomarkers.

Extracellular vesicles as mediators of immunopathology in infectious diseases

In the last decades, extracellular vesicles have emerged as important elements in cell-cell communication and as key players in disease pathogenesis via transmission of their cargo between different cells. Various works have described different subpopulations of these membrane structures, based on their cell of origin, biogenesis, size, biophysical properties and cargo. In addition to their pathophysiological role in the development and progression of different diseases including infectious diseases, neurodegenerative disorders and cancer, extracellular vesicles are now recognized for their potential as novel therapeutic targets and intelligent drug delivery system. Here, we have reviewed the most recent data on different subtypes of extracellular vesicles, focusing on microvesicles and exosomes and their subpopulations, their involvement in immune-mediated pathogenesis of various infectious diseases and their role as potential therapeutic targets.