Refining Flow Cytometry-based Sorting of Plasma-derived Extracellular Vesicles.

We reported a microfluidic system for sorting of extracellular vesicles (EVs), which can house DNAs, RNAs, lipids, proteins, and metabolites that are important in intercellular communication. Their presence within bodily fluids has demonstrated potential in both clinical diagnostic and therapeutic applications. Furthermore, EVs exhibit distinct subtypes categorized by their sizes, each endowed with unique biophysical properties. Despite several existing techniques for EV isolation and purification, diminished purity and prolonged processing times still hamper clinical utility; comprehensive capture of EVs remains an ongoing pursuit. To address these challenges, we devised an innovative method for automated sorting of nano-scale EVs employing optically-induced dielectrophoresis on an integrated microfluidic chip. With this approach, EVs of three distinct size categories (small: 100-150 nm, medium-sized: 150-225 nm, and large: 225-350 nm) could be isolated at a purity of 86%. This new method has substantial potential in expediting EV research and diagnostics.

Sorting of extracellular vesicles has important applications in early stage diagnostics. Current exosome isolation techniques, however, suffer from being costly, having long processing times, and producing low purities. Recent work has shown that active sorting via acoustic and electric fields are useful techniques for microscale separation activities, where combining these has the potential to take advantage of multiple force mechanisms simultaneously. In this work, we demonstrate an approach using both electrical and acoustic forces to manipulate bioparticles and submicrometer particles for deterministic sorting, where we find that the concurrent application of dielectrophoretic (DEP) and acoustophoretic forces decreases the critical diameter at which particles can be separated. We subsequently utilize this approach to sort subpopulations of extracellular vesicles, specifically exosomes (<200 nm) and microvesicles (>300 nm). Using our combined acoustic/electric approach, we demonstrate exosome purification with more than 95% purity and 81% recovery, well above comparable approaches.

Extracellular vesicles (EVs) are sub-micron-sized membranous spheres secreted by cells. EVs play a functional role as intercellular communicators and are associated with a number of diseases. Research into EVs is an area of growing interest due their many potential uses as therapeutic agents, as diagnostic and theranostic biomarkers, and as regulators of cellular biology. Flow cytometry is a popular method for enumerating and phenotyping EVs, even though the majority of EVs are below the detection sensitivity of most commercially available flow cytometers. Here, we present optimized protocols for EV labeling that increase the signal-to-noise ratio of EVs by removing residual antibody. Protocols for alignment of high-resolution jet-in-air flow cytometers are also provided. Published 2020. U.S. Government. Basic Protocol 1: Bulk EV staining with CFSE protein binding dye Basic Protocol 2: Antigen-specific staining of EV markers with fluorochrome-conjugated antibodies Basic Protocol 3: Astrios EQ instrument setup and sample acquisition Basic Protocol 4: Counting particles and EVs on Astrios EQ with spike-in reference beads.

Methods for the isolation and analysis of extracellular vesicles (EVs) have been extensively explored in the field of life science and in clinical diagnosis in recent years. The separation and efficient recovery of high-purity target EVs from biological samples are important prerequisites in the study of EVs. So far, commonly used methods of EV separation include ultracentrifugation, filtration, solvent precipitation and immunoaffinity capturing. However, these methods suffer from long processing time, EV damage and low enrichment efficiency. The use of acoustophoretic force facilitates the non-contact label-free manipulation of cells based on their size and compressibility but lacks specificity. Additionally, the acoustophoretic force exerted on sub-micron substances is normally weak and insufficient for separation. Here we present a novel immuno-acoustic sorting technology, where biological substances such as EVs, viruses, and biomolecules, can be specifically captured by antibody/receptor coated microparticles through immunoaffinity, and manipulated by an acoustophoretic force exerted on the microparticles. Using immuno-acoustic sorting technology, we successfully separated and purified HER2-positive EVs for further downstream analysis. This method holds great potential in isolating and purifying specific targets such as disease-related EVs from biological fluids and opens new possibilities for the EV-based early diagnosis and prognosis of diseases.

Extracellular vesicles (EVs) are nanovesicles secreted for intercellular communication with endosomal network regulating secretion of small EVs (or exosomes) that play roles in cancer progression. As an essential oncoprotein, Kirsten rat sarcoma virus (KRAS) is tightly regulated by its endosomal trafficking for membrane attachment. However, the crosstalk between KRAS and EVs has been scarcely discussed despite its endocytic association. An overview of the oncogenic role of KRAS focusing on its correlation with cancer-associated EVs should provide important clues for disease prognosis and inspire novel therapeutic approaches for treating KRAS mutant cancers. Therefore, this review summarizes the relevant studies that provide substantial evidence linking KRAS mutation to EVs and discusses the oncogenic implication from the aspects of biogenesis, cargo sorting, and release and uptake of the EVs.

Proteomics of plasma-derived extracellular vesicles reveals S100A8 as a novel biomarker for Alzheimer's disease: A preliminary study

BackgroundInfection and graft-versus-host disease (GvHD) are the major causes for mortality and morbidity of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Plasma-derived extracellular vesicles (EVs) contain disease-related proteins, DNAs and RNAs, and have recently been suggested as potential biomarker candidates for transplantation complications. However, EV isolation from small plasma volumes in clinical biomarker studies using conventional methods is challenging. We therefore investigated if EVs isolated by novel automated acoustic trapping could be developed as potential biomarkers for allo-HSCT complications by performing a clinical proof-of-principle study.ResultsPlasma samples were collected from twenty consecutive patients with high-risk/relapsed hematologic malignancies undergoing allo-HSCT before transplantation and post-transplant up to 12 weeks. EVs were isolated from small plasma sample volumes (150 μl) by an automated, acoustofluidic-based particle trapping device, which utilizes a local λ/2 ultrasonic standing wave in a borosilicate glass capillary to capture plasma EVs among pre-seeded polystyrene microbeads through sound scatter interactions. We found that EVs could be reliably isolated from all plasma samples (n = 173) and that EV numbers increased more than 2-fold in the majority of patients after transplantation. Also, sufficient quantities of RNA for downstream microRNA (miRNA) analysis were obtained from all samples and EV miRNA profiles were found to differ from whole plasma profiles. As a proof of principle, expression of platelet-specific miR-142-3p in EVs was shown to correlate with platelet count kinetics after transplantation as expected. Importantly, we identified plasma EV miRNAs that were consistently positively correlated with infection and GvHD, respectively, as well as miRNAs that were consistently negatively correlated with these complications.ConclusionsThis study demonstrates that acoustic enrichment of EVs in a clinical biomarker study setting is feasible and that downstream analysis of acoustically-enriched EVs presents a promising tool for biomarker development in allo-HSCT. Certainly, these findings warrant further exploration in larger studies, which will have significant implications not only for biomarker studies in transplantation but also for the broad field of EV-based biomarker discovery.

Extracellular vesicles (EVs) are heavily implicated in diverse pathological processes. Due to their small size, distinct biogenesis, and heterogeneous marker expression, isolation and detection of single EV subpopulations are difficult. Here, we develop a λ-DNA- and aptamer-mediated approach allowing for simultaneous size-selective separation and surface protein analysis of individual EVs. Using a machine learning algorithm to EV signature based on their size and marker expression, we demonstrate that the isolated microvesicles are more efficient than exosomes and apoptotic bodies in discriminating breast cell lines and Stage II breast cancer patients with varied immunohistochemical expression of HER2. Our method provides an important tool to assess the EV heterogeneity at the single EV level with potential value in clinical diagnostics.

Trichomonas vaginalis is a common sexually transmitted extracellular parasite that adheres to epithelial cells in the human urogenital tract. Extracellular vesicles (EVs) have been described as important players in the pathogenesis of this parasite as they deliver proteins and RNA into host cells and modulate parasite adherence. EVs are heterogeneous membrane vesicles released from virtually all cell types that collectively represent a new dimension of intercellular communication. The Endosomal Sorting Complex Required for Transport (ESCRT) machinery contributes to several key mechanisms in which it reshapes membranes. Based on this, some components of the ESCRT have been implicated in EVs biogenesis in other cells. Here, we demonstrated that VPS32, a member of ESCRTIII complex, contribute to the biogenesis and cargo sorting of extracellular vesicles in the parasite T. vaginalis. Moreover, we observe that parasites overexpressing VPS32 have a striking increase in adherence to host cells compared to control parasites; demonstrating a key role for this protein in mediating host: parasite interactions. These results provide valuable information on the molecular mechanisms involved in extracellular vesicles biogenesis, cargo-sorting, and parasite pathogenesis.

&lt;div&gt;Abstract&lt;p&gt;Disease progression following androgen ablation was shown to be associated with upregulation of the glucocorticoid receptor (GR). Longitudinal monitoring of GR expression in circulating extracellular vesicles (EV) may reflect changes in the tumor cell and facilitates detection of acquired resistance. We utilized LNCaP, LREX cells and a patient-derived xenograft, MDA PDX 322-2-6a, for &lt;i&gt;in vitro&lt;/i&gt; and &lt;i&gt;in vivo&lt;/i&gt; experiments. Plasma-derived EVs were isolated from patients with localized high-risk prostate cancer undergoing androgen ablation. The mRNA levels of GR in EVs and their responsive genes were detected by transcriptome analysis, qRT-PCR and the protein levels by Western blot analysis. We detected changes in GR expression at mRNA and protein levels in EVs derived from LNCaP and LREX cells in &lt;i&gt;in vitro&lt;/i&gt; studies. In &lt;i&gt;in vivo&lt;/i&gt; experiments, LNCaP and the PDX MDA 322-2-6a–bearing mice were treated with enzalutamide. GR levels in plasma-derived EVs were increased only in those tumors that did not respond to enzalutamide. Treatment of mice bearing enzalutamide-resistant tumors with a GR inhibitor in combination with enzalutamide led to a transient pause in tumor growth in a subset of tumors and decreased GR levels intracellular and in plasma-derived EVs. In a subgroup of patients with high-risk localized prostate cancer treated with androgen signaling inhibition, GR was found upregulated in matching tissue and plasma EVs. These analyses showed that GR levels in plasma-derived EVs may be used for monitoring the transition of GR expression allowing for early detection of resistance to androgen ablation treatment.&lt;/p&gt;Significance:&lt;p&gt;Longitudinal monitoring of GR expression in plasma-derived EVs from patients with prostate cancer treated with androgen signaling inhibitors facilitates early detection of acquisition of resistance to androgen receptor signaling inhibition in individual patients.&lt;/p&gt;&lt;/div&gt;

&lt;div&gt;Abstract&lt;p&gt;Disease progression following androgen ablation was shown to be associated with upregulation of the glucocorticoid receptor (GR). Longitudinal monitoring of GR expression in circulating extracellular vesicles (EV) may reflect changes in the tumor cell and facilitates detection of acquired resistance. We utilized LNCaP, LREX cells and a patient-derived xenograft, MDA PDX 322-2-6a, for &lt;i&gt;in vitro&lt;/i&gt; and &lt;i&gt;in vivo&lt;/i&gt; experiments. Plasma-derived EVs were isolated from patients with localized high-risk prostate cancer undergoing androgen ablation. The mRNA levels of GR in EVs and their responsive genes were detected by transcriptome analysis, qRT-PCR and the protein levels by Western blot analysis. We detected changes in GR expression at mRNA and protein levels in EVs derived from LNCaP and LREX cells in &lt;i&gt;in vitro&lt;/i&gt; studies. In &lt;i&gt;in vivo&lt;/i&gt; experiments, LNCaP and the PDX MDA 322-2-6a–bearing mice were treated with enzalutamide. GR levels in plasma-derived EVs were increased only in those tumors that did not respond to enzalutamide. Treatment of mice bearing enzalutamide-resistant tumors with a GR inhibitor in combination with enzalutamide led to a transient pause in tumor growth in a subset of tumors and decreased GR levels intracellular and in plasma-derived EVs. In a subgroup of patients with high-risk localized prostate cancer treated with androgen signaling inhibition, GR was found upregulated in matching tissue and plasma EVs. These analyses showed that GR levels in plasma-derived EVs may be used for monitoring the transition of GR expression allowing for early detection of resistance to androgen ablation treatment.&lt;/p&gt;Significance:&lt;p&gt;Longitudinal monitoring of GR expression in plasma-derived EVs from patients with prostate cancer treated with androgen signaling inhibitors facilitates early detection of acquisition of resistance to androgen receptor signaling inhibition in individual patients.&lt;/p&gt;&lt;/div&gt;

ABSTRACTBiological nanoparticles, including viruses and extracellular vesicles (EVs), are of interest to many fields of medicine as biomarkers and mediators of or treatments for disease. However, exosomes and small viruses fall below the detection limits of conventional flow cytometers due to the overlap of particle-associated scattered light signals with the detection of background instrument noise from diffusely scattered light. To identify, sort, and study distinct subsets of EVs and other nanoparticles, as individual particles, we developed nanoscale Fluorescence Analysis and Cytometric Sorting (nanoFACS) methods to maximise information and material that can be obtained with high speed, high resolution flow cytometers. This nanoFACS method requires analysis of the instrument background noise (herein defined as the “reference noise”). With these methods, we demonstrate detection of tumour cell-derived EVs with specific tumour antigens using both fluorescence and scattered light parameters. We further validated the performance of nanoFACS by sorting two distinct HIV strains to >95% purity and confirmed the viability (infectivity) and molecular specificity (specific cell tropism) of biological nanomaterials sorted with nanoFACS. This nanoFACS method provides a unique way to analyse and sort functional EV- and viral-subsets with preservation of vesicular structure, surface protein specificity and RNA cargo activity.

Lipids are a major component of cells that can influence multiple cellular functions. Our group previously found that the breast cancer cells could dramatically change their lipid profile during their progression. Thus, we hypothesized that the lipid profile of extracellular vesicles (EVs) could be used as a biomarker for breast cancer (BC) since the lipid profiles of breast cancer cells can be reflected in that of EVs secreted from cancer cells. In the present study, we optimized a method to isolate EVs from human plasma samples that could be used for the comprehensive lipid analysis. We then explored specific lipid profiles in plasma-derived EVs that could discriminate BC and healthy individuals, tumor subtypes and stages. Plasma-derived EVs from breast cancer (n = 105), benign (n = 11), and healthy individuals (n = 43) were used for lipid analysis. The results showed that the change in proportion of the lipids in the EVs could well discriminate stages and subtypes of BC. The proportion of major phospholipids, phosphatidylethanolamines, phosphatidylserines, phosphatidylcholines (PCs) and phosphatidylinositols (PIs) showed different patterns at different stages. Importantly, PI (18:0/20:3), which we previously identified as a lipid biomarker of disease progression expressed in the primary breast cancer tissue, showed a similar trend in the plasma-derived EVs. This finding supports our initial hypothesis. Besides the phospholipids, sphingomyelins were found to be higher in stage IV. With regard to tumor subtypes, PCs and ceramides were enriched in HER2-positive subtype, while lysoPCs and polyunsaturated triglycerides were enriched in triple negative subtype. Furthermore, a BC diagnostic model consisting of three lipids was successfully established and the model showed good performance in discriminating between healthy individuals and BC in the two independent data sets (the area under the ROC curve was estimated around 0.759 to 0.804). In conclusion, profiling of lipids in plasma-derived EVs has the potential to be used as a liquid biopsy that can diagnose BC, and its stages and subtypes. Further validation and improvement in EV isolation technique would be needed to achieve sufficient performance sufficient for clinical application. Citation Format: Masahiro Kawashima. Liquid biopsy based on the lipid profiles in plasma-derived extracellular vesicles which can be utilized for breast cancer diagnosis [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C004.

Introduction: Although genetic and transcriptomic analysis of tumor tissue can provide useful information for prognosis and treatment decision making, 5-20% of advanced-stage lung cancer patients cannot be biopsied, or the amount of tumor tissue is insufficient for successful analysis. In addition, repeated sampling is often not possible. Liquid biopsies have shown potential to be used as minimally invasive, safe and sensitive alternative for tissue biopsies, but lack of standardized protocols is hampering implementation in the clinic. The nCounter platform could provide the solution for this problem, with an easy-to-use technical workflow and straightforward data analysis. Extracellular vesicles (EVs) are mediators of intercellular communication and may play a role in early cancer development. Therefore, RNA found within EVs can be used as a biomarker for cancer development and progression. In addition, the lipid bilayer of EVs makes their cargo particularly stable and allows the use of biobank stored samples. Methods: EVs were isolated from 600 μL plasma of 19 cancer patients and 10 healthy donors, using the miRCURY® Exosome Serum/Plasma Kit (Qiagen), and total RNA was extracted using TRI Reagent® (MRC Inc) or the automated QIAsymphony® System (Qiagen) with the DSP Virus/Pathogen Kit, after RNAse A (Sigma-Aldrich) treatment to remove plasma cell-free RNA. The Human Immune V2 panel (NanoString Technologies), including 600 mRNA targets, was used to analyze EV-derived mRNA after a pre-amplification (pre-amp) step with the Low RNA Input Amplification Kit. In addition, the Human V3 miRNA panel (NanoString Technologies), including 800 miRNA targets, was used to analyze the same EV samples without pre-amp. Results: Total amount of RNA isolated from EVs was found to be significantly higher using TRI Reagent®, versus automated RNA isolation. In addition, the conditions for the pre-amp step were tested and optimized. A pre-amp of 10 cycles for the mRNA panel was shown to be sufficient to detect mRNA targets in EVs without saturation, and the NanoString retrotranscription (RT) enzyme outperformed the other RT enzyme tested. In addition, supernatant collected during EV isolation was also analyzed, and results showed that the RNA targets were derived from within the EVs. On average, 337 mRNA targets were detected within the EVs, while 157 miRNA targets were detected in the same samples without pre-amp, with no significant differences between cancer patients and healthy donors. Interestingly, most differentially expressed (DE) mRNAs were shown to be lower expressed in cancer patients, while most DE miRNAs were found to be higher expressed in cancer patients. Conclusion: Our results demonstrate that the nCounter NanoString platform can be used for miRNA and mRNA detection in plasma-derived EVs from cancer patients and healthy donors. Further studies will focus on specific mRNA and miRNA expression differences between these two cohorts. Citation Format: Jillian Wilhelmina Bracht, Ana Gimenez-Capitan, Chung-Ying Huang, Carlos Pedraz-Valdunciel, Joselyn Valarezo, Sarah Warren, Rafael Rosell, Miguel Angel Molina-Vila. miRNA and mRNA detection in plasma-derived extracellular vesicles (EVs) using the nCounter NanoString platform [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 760.

The influence of radiation-induced bystander effect in osteoblasts mediated by plasma-derived extracellular vesicles (EVs)