Exosome Separation Research Articles

Separation of plasma-derived exosomes into CD3(+) and CD3(-) fractions allows for association of immune cell and tumour cell markers with disease activity in HNSCC patients.

Head and neck squamous cell carcinoma (HNSCC) is a highly immunosuppressive malignancy. Exosomes in HNSCC patients' plasma are enriched in inhibitory cargo and mediate immunosuppression. As these exosomes are products of various cells, the cellular origin of immunoregulatory proteins they carry is unknown. To test whether tumour- or T cell-derived exosomes in patients' plasma are immunosuppressive and impact upon disease activity, we separated CD3(-) from CD3(+) exosomes by immunocapture using anti-CD3 antibodies. The exosome protein cargo was evaluated for immunoregulatory proteins using on-bead flow cytometry. Tumour protein-enriched CD3(-) exosomes were CD44v3(+) . Surprisingly, mean levels of programmed death ligand 1 (PD-L1), cytotoxic T lymphocyte antigen 4 (CTLA-4) and cyclooxygenase-2 (COX-2) were similar in CD3(+) and CD3(-) exosomes, although the latter induced higher (P<0·0025) ex-vivo apoptosis of CD8(+) T cells and greater (P<0·005) conversion of CD4+ T cells to CD4(+) CD39(+) regulatory T cells (Treg ). CD3(+) and CD3(-) exosomes carrying high levels of immunosuppressive proteins were highly effective in mediating these functions. Exosomes of patients with Union for International Cancer Control (UICC) stages III/IV disease had higher levels of PD-L1 and COX-2 than stages I/II patients (P<0·005). Patients with nodal involvement had exosomes with the higher inhibitory protein content than N0 patients (P<0·03). CD3(+) and CD3(-) exosomes of HNSCC patients had higher PD-L1, COX-2 and CD15s levels than healthy donors' exosomes (P<0·009), although levels of immunostimulatory OX40 or OX40L were not different. By isolating CD3(-) /CD44v3-enriched and CD3(+) exosomes from plasma, the cellular origins of immunoregulatory proteins they carry were identified. Association of exosome molecular profiles with disease progression supports the exosome potential as future cancer biomarkers.

Serum Exosomal MiR-92b-5p as a Potential Biomarker for Acute Heart Failure Caused by Dilated Cardiomyopathy

Background/Aims: MicroRNAs (miRNAs) can be used as biomarkers for cardiovascular diseases, especially for heart failure. However, there are few reports on serum exosomal miRNA biomarkers in patients with acute heart failure (AHF) due to Dilated cardiomyopathy (DCM). Methods: We analyzed 3 different serum exosomal miRNAs (exo-miR-92b-5p, exo-miR-192-5p, and exo-miR-320a) in 43 patients with DCM-AHF and 34 healthy volunteers as a control group (CG) by using exosome separation followed by a quantitative reverse-transcript PCR assay. Exosomes were identified by electron microscopy, NaNOZS-90, and western blot analyses (CD63 and Hsp70). Results: Serum exo-miR-92b-5p expression was increased in DCM-AHF patients compared to the CG (Mann–Whitney U-test: P < 0.001). Exo-miR-92b-5p was positively related to age and some ultrasound data (Spearman’s correlation: exo-miR-92b-5p vs. age, r = 0.297, P = 0.014; exo-miR-92b-5p vs. left atrial diameter, r = 0.431, P < 0.001; exo-miR-92b-5p vs. left ventricular diastolic diameter, r = 0.419, P < 0.001; exo-miR-92b-5p vs. left ventricular systolic diameter, r = 0.446, P < 0.001). Exo-miR-92b-5p was also negatively related to other ultrasound data (Spearman’s correlation: exo-miR-92b-5p vs. left ventricular fraction shortening, r = -0.497, P < 0.001; exo-miR-92b-5p vs. left ventricular ejection fraction, r = -0.482, P < 0.001). The discrimination of DCM-AHF patients from the CG by exo-miR-92b-5p was demonstrated by a receiver operating characteristic curve (exo-miR-92b-5p: cutoff value = 0.0023, area under the curve = 0.808, P < 0.001, sensitivity = 62.8%, specificity = 85.3%). Conclusion: Serum exo-miR-92b-5p is a potential biomarker for the diagnosis of DCM-AHF.

Exosome separation using microfluidic systems: size-based, immunoaffinity-based and dynamic methodologies.

Exosomes, nanovesicles secreted by most types of cells, exist in virtually all bodily fluids. Their rich nucleic acid and protein content make them potentially valuable biomarkers for noninvasive molecular diagnostics. They also show promise, after further development, to serve as a drug delivery system. Unfortunately, existing exosome separation technologies, such as ultracentrifugation and methods incorporating magnetic beads, are time-consuming, laborious and separate only exosomes of low purity. Thus, a more effective separation method is highly desirable. Microfluidic platforms are ideal tools for exosome separation, since they enable fast, cost-efficient, portable and precise processing of nanoparticles and small volumes of liquid samples. Recently, several microfluidic-based exosome separation technologies have been studied. In this article, the advantages of the most recent technologies, as well as their limitations, challenges and potential uses in novel microfluidic exosome separation and collection applications is reviewed. This review outlines the uses of new powerful microfluidic exosome detection tools for biologists and clinicians, as well as exosome separation tools for microfluidic engineers. Current challenges of exosome separation methodologies are also described, in order to highlight areas for future research and development.

On-Chip Liquid Biopsy: Progress in Isolation of Exosomes for Early Diagnosis of Cancer

In contrast to a standard biopsy, the so-called ‘liquid biopsy’offers a rapid, non-invasive, and cost effective alternative for cancer diagnosis. Exosomes, which are secreted by most eukaryotic cells and range in size from 30-150nm, are the enabling biocolloid in this technique as they carry a diverse variety of genetically rich cargo, including proteins, RNA, and DNA. Hence, studying exosomes could potentially provide vital information about undesirable genetic deviations occurring in their cell of origin. Rapid isolation of exosomes from blood, urine or other body fluids remains a key challenge in this growing field.Deterministic lateral displacement (DLD) pillar arrays have proven an effective means to sort, segregate, and enrich micron-size particles, such as parasites and blood cells. Here, we have developed a nanoscale DLD devices, containing gap sizes as small as ∼25nm, with nanoscale sorting resolution of biological particles. This development in nanofluidics and engineering has enabled us to sort colloidal particles at the tens of nanometers scale. Additionally, we have developed predictive computational models to provide key insights into the behavior of particles in these systems. Furthermore, we have successfully demonstrated on-chip, size-based separation of exosomes, indicating the potential of this technology for sorting plasma, urine, serum or circulating tumor-derived exosomes.

Using endogenous ligands for direct superparamagnetic nanoparticle cluster-based body fluid exosome separation

Using endogenous ligands to directly separate exosomes from body fluids facilitates the in vivo clinical translation of exosomes.

Isolation and Identification of miRNAs in exosomes derived from serum of colon cancer patients.

Objective: To isolate exosomes from the serum of colon cancer patients and identify RNAs in the small vesicles.Methods: ExoQuick-TC™ Exosome Precipitation Solution was used for exosome isolation and the shapes of exosomes were observed under a transmission electron microscope. Mass spectrometry was used to identify the classification of miRNAs encapsulated in exosomes, and the expression levels of miRNA-21,-133a, and -181b in exosomes were detected by RT-PCR.Results: Exosomes isolated from serum of colon cancer patients were circular-or oval-shaped and vary in size with a diameter of 40-100 nm. Mass spectrometry shows that the main RNAs in exosomes are small RNAs; the levels of these small RNAs in exosomes are significantly higher compared with fresh serum. There is still a tiny amount of small RNAs in exosome-free serum, but the amounts are significantly lower than that in exosomes. No more RNAs were detected in the repeated freezing and thawing serum, but there were still some RNAs detectable in the exosomes extracted from these serums. MiRNA-21, -133a and -181b can be detected in exosomes, and the level of miRNA-21 is associated with early diagnosis of colon cancer.Conclusion: This study proves that commercial kits for exosome separation are more convenient and time-saving and that mass spectrometry is capable of identifying the miRNAs in exosomes. Compared with direct extraction of miRNAs from the serum, the method of isolating exosomes from the serum firstly and then extracting miRNAs from the exosomes can enhance the stability and integrity of their inner miRNAs. Also, we demonstrate that the exosomal miRNA-21 expression is associated with the early diagnosis of colon cancer.

Isolation of Exosomes from the Plasma of HIV-1 Positive Individuals

Exosomes are small vesicles ranging in size from 30 nm to 100 nm that are released both constitutively and upon stimulation from a variety of cell types. They are found in a number of biological fluids and are known to carry a variety of proteins, lipids, and nucleic acid molecules. Originally thought to be little more than reservoirs for cellular debris, the roles of exosomes regulating biological processes and in diseases are increasingly appreciated. Several methods have been described for isolating exosomes from cellular culture media and biological fluids. Due to their small size and low density, differential ultracentrifugation and/or ultrafiltration are the most commonly used techniques for exosome isolation. However, plasma of HIV-1 infected individuals contains both exosomes and HIV viral particles, which are similar in size and density. Thus, efficient separation of exosomes from HIV viral particles in human plasma has been a challenge. To address this limitation, we developed a procedure modified from Cantin et. al., 2008 for purification of exosomes from HIV particles in human plasma. Iodixanol velocity gradients were used to separate exosomes from HIV-1 particles in the plasma of HIV-1 positive individuals. Virus particles were identified by p24 ELISA. Exosomes were identified on the basis of exosome markers acetylcholinesterase (AChE), and the CD9, CD63, and CD45 antigens. Our gradient procedure yielded exosome preparations free of virus particles. The efficient purification of exosomes from human plasma enabled us to examine the content of plasma-derived exosomes and to investigate their immune modulatory potential and other biological functions.

Isolation of Exosomes from the Plasma of HIV-1 Positive Individuals

Exosomes are small vesicles ranging in size from 30 nm to 100 nm that are released both constitutively and upon stimulation from a variety of cell types. They are found in a number of biological fluids and are known to carry a variety of proteins, lipids, and nucleic acid molecules. Originally thought to be little more than reservoirs for cellular debris, the roles of exosomes regulating biological processes and in diseases are increasingly appreciated. Several methods have been described for isolating exosomes from cellular culture media and biological fluids. Due to their small size and low density, differential ultracentrifugation and/or ultrafiltration are the most commonly used techniques for exosome isolation. However, plasma of HIV-1 infected individuals contains both exosomes and HIV viral particles, which are similar in size and density. Thus, efficient separation of exosomes from HIV viral particles in human plasma has been a challenge. To address this limitation, we developed a procedure modified from Cantin et. al., 2008 for purification of exosomes from HIV particles in human plasma. Iodixanol velocity gradients were used to separate exosomes from HIV-1 particles in the plasma of HIV-1 positive individuals. Virus particles were identified by p24 ELISA. Exosomes were identified on the basis of exosome markers acetylcholinesterase (AChE), and the CD9, CD63, and CD45 antigens. Our gradient procedure yielded exosome preparations free of virus particles. The efficient purification of exosomes from human plasma enabled us to examine the content of plasma-derived exosomes and to investigate their immune modulatory potential and other biological functions.

Urine Proteome Biomarkers in Kidney Diseases. I. Limits, Perspectives, and First Focus on Normal Urine.

Urine proteome is a potential source of information in renal diseases, and it is considered a natural area of investigation for biomarkers. Technology developments have markedly increased the power analysis on urinary proteins, and it is time to confront methodologies and results of major studies on the topics. This is a first part of a series of reviews that will focus on the urine proteome as a site for detecting biomarkers of renal diseases; the theme of the first review concerns methodological aspects applied to normal urine. Main issues are techniques for urine pretreatment, separation of exosomes, use of combinatorial peptide ligand libraries, mass spectrometry approaches, and analysis of data sets. Available studies show important differences, suggesting a major confounding effect of the technologies utilized for analysis. The objective is to obtain consensus about which approaches should be utilized for studying urine proteome in renal diseases.

A review of exosome separation techniques and characterization of B16-F10 mouse melanoma exosomes with AF4-UV-MALS-DLS-TEM.

Exosomes participate in cancer metastasis, but studying them presents unique challenges as a result of their small size and purification difficulties. Asymmetrical field flow fractionation with in-line ultraviolet absorbance, dynamic light scattering, and multi-angle light scattering was applied to the size separation and characterization of non-labeled B16-F10 exosomes from an aggressive mouse melanoma cell culture line. Fractions were collected and further analyzed using batch mode dynamic light scattering, transmission electron microscopy and compared with known size standards. Fractogram peak positions and computed radii show good agreement between samples and across fractions. Ultraviolet absorbance fractograms in combination with transmission electron micrographs were able to resolve subtle heterogeneity of vesicle retention times between separate batches of B16-F10 exosomes collected several weeks apart. Further, asymmetrical field flow fractionation also effectively separated B16-F10 exosomes into vesicle subpopulations by size. Overall, the flow field flow fractionation instrument combined with multiple detectors was able to rapidly characterize and separate exosomes to a degree not previously demonstrated. These approaches have the potential to facilitate a greater understanding of exosome function by subtype, as well as ultimately allow for "label-free" isolation of large scale clinical exosomes for the purpose of developing future exosome-based diagnostics and therapeutics.

Miniaturized asymmetrical flow field‐flow fractionation: Application to biological vesicles

Asymmetrical flow field-flow fractionation (AFlFFF) has been carried out in a miniaturized channel by reducing the channel dimensions. Performance of the miniaturized AFlFFF (mAFlFFF) channel was evaluated with standard proteins and polystyrene latex spheres from nanometer to micrometer size. By reducing the channel dimension, proteins or particulate materials can be separated within a few minutes without a significant loss in resolution. The mAFlFFF channel was applied for the separation of exosomes harvested from immortalized human mesenchymal stem cell line. It shows a potential to fractionate exosome vesicles according to sizes which can be useful for proteomic studies in relation to immunotherapeutic applications.

Platelet-derived exosomes from septic shock patients induce myocardial dysfunction

IntroductionMechanisms underlying inotropic failure in septic shock are incompletely understood. We previously identified the presence of exosomes in the plasma of septic shock patients. These exosomes are released mainly by platelets, produce superoxide, and induce apoptosis in vascular cells by a redox-dependent pathway. We hypothesized that circulating platelet-derived exosomes could contribute to inotropic dysfunction of sepsis.MethodsWe collected blood samples from 55 patients with septic shock and 12 healthy volunteers for exosome separation. Exosomes from septic patients and healthy individuals were investigated concerning their myocardial depressant effect in isolated heart and papillary muscle preparations.ResultsExosomes from the plasma of septic patients significantly decreased positive and negative derivatives of left ventricular pressure in isolated rabbit hearts or developed tension and its first positive derivative in papillary muscles. Exosomes from healthy individuals decreased these variables non-significantly. In hearts from rabbits previously exposed to endotoxin, septic exosomes decreased positive and negative derivatives of ventricular pressure. This negative inotropic effect was fully reversible upon withdrawal of exosomes. Nitric oxide (NO) production from exosomes derived from septic shock patients was demonstrated by fluorescence. Also, there was an increase in myocardial nitrate content after exposure to septic exosomes.ConclusionCirculating platelet-derived exosomes from septic patients induced myocardial dysfunction in isolated heart and papillary muscle preparations, a phenomenon enhanced by previous in vivo exposure to lipopolysaccharide. The generation of NO by septic exosomes and the increased myocardial nitrate content after incubation with exosomes from septic patients suggest an NO-dependent mechanism that may contribute to myocardial dysfunction of sepsis.

Molecular characterization of a carbamoyl-phosphate synthetase II (CPS II) gene from Leishmania mexicana

Magnetic materials have been widely used in bioseparation in recent years due to their good biocompatibility, magnetic properties, and high binding capacity. In this review, we provide a brief introduction on the preparation and bioseparation applications of magnetic materials including the synthesis and surface modification of magnetic nanoparticles as well as the preparation and applications of magnetic nanocomposites in the separation of proteins, peptides, cells, exosomes and blood. The current limitations and remaining challenges in the fabrication process of magnetic materials for bioseparation will be also detailed.