Journal of extracellular biology最新文献

The receptor tyrosine kinase (RTK) KIT and its ligand stem cell factor (SCF) are essential for human mast cell (huMC) survival and proliferation. HuMCs expressing oncogenic KIT variants secrete large numbers of extracellular vesicles (EVs). The role KIT plays in regulating EV secretion has not been examined. Here, we investigated the effects of stimulation or inhibition of KIT activity on the secretion of small EVs (sEVs). In huMCs expressing constitutively active KIT, the quantity and quality of secreted sEVs positively correlated with the activity status of KIT. SCF-mediated stimulation of KIT in huMCs or murine MCs, or of transiently expressed KIT in HeLa cells, enhanced the release of sEVs expressing exosome markers. In contrast, ligand-mediated stimulation of the RTK EGFR in HeLa cells did not affect sEV secretion. The release of sEVs induced by either constitutively active or ligand-activated KIT was remarkably decreased when cells were treated with KIT inhibitors, concomitant with reduced exosome markers in sEVs. Similarly, inhibition of oncogenic KIT signalling kinases like PI3K, and MAPK significantly reduced the secretion of sEVs. Thus, activation of KIT and its early signalling cascades stimulate the secretion of exosome-like sEVs in a regulated fashion, which may have implications for KIT-driven functions.

Urinary extracellular vesicles (uEVs) are rich in valuable biomolecule information which are increasingly recognized as potential biomarkers for various diseases. uEV long RNAs are among the critical cargos capable of providing unique transcriptome information of the source cells. However, consensus regarding ideal reference genes for relative long RNAs quantification in uEVs is not available as of date. Here we explored stable reference genes through profiling the long RNA expression by RNA-seq following unsupervised analysis and validation studies. Candidate reference genes were identified using four algorithms: NormFinder, GeNorm, BestKeeper and the Delta Ct method, followed by validation. RNA profile showed uEVs contained abundant long RNAs information and the core transcriptome was related to cellular structures, especially ribosome which functions mainly as translation, protein and RNA binding molecules. Analysis of RNA-seq data identified RPL18A, RPL11, RPL27, RACK1, RPSA, RPL41, H1-2, RPL4, GAPDH, RPS27A as candidate reference genes. RT-qPCR validation revealed that RPL41, RPSA and RPL18A were reliable reference genes for long RNA quantification in uEVs from patients with diabetes mellitus (DM), diabetic nephropathy (DN), IgA nephropathy (IgAN) and prostate cancer (PCA). Interestingly, RPL41 also outperformed traditional reference genes in renal tissues of DN and IgAN, as well as in plasma EVs of several types of cancers. The stable reference genes identified in this study may facilitate development of uEVs as novel biomarkers and increase the accuracy and comparability of biomarker studies.

Cells can communicate via the release and uptake of extracellular vesicles (EVs), which are nano-sized membrane vesicles that can transfer protein and RNA cargo between cells. EVs contain microRNAs and various other types of non-coding RNA, of which Y RNA is among the most abundant types. Studies on how RNAs and their binding proteins are sorted into EVs have mainly focused on comparing intracellular (cytoplasmic) levels of these RNAs to the extracellular levels in EVs. Besides overall transcriptional levels that may regulate sorting of RNAs into EVs, the process may also be driven by local intracellular changes in RNA/RBP concentrations. Changes in extracellular Y RNA have been linked to cancer and cardiovascular diseases. Although the loading of RNA cargo into EVs is generally thought to be influenced by cellular stimuli and regulated by RNA binding proteins (RBP), little is known about Y RNA shuttling into EVs. We previously reported that immune stimulation alters the levels of Y RNA in EVs independently of cytosolic Y RNA levels. This suggests that Y RNA binding proteins, and/or changes in the local Y RNA concentration at EV biogenesis sites, may affect Y RNA incorporation into EVs. Here, we investigated the subcellular distribution of Y RNA and Y RNA binding proteins in activated and non-activated THP1 macrophages. We demonstrate that Y RNA and its main binding protein Ro60 abundantly co-fractionate in organelles involved in EV biogenesis and in EVs. Cellular activation led to an increase in Y RNA concentration at EV biogenesis sites and this correlated with increased EV-associated levels of Y RNA and Ro60. These results suggest that Y RNA incorporation into EVs may be controlled by local intracellular changes in the concentration of Y RNA and their protein binding partners.

Placental extracellular vesicles (EVs) can be found in the maternal circulation throughout gestation, and their concentration, content and bioactivity are associated with pregnancy outcomes, including gestational diabetes mellitus (GDM). However, the effect of changes in the maternal microenvironment on the mechanisms associated with the secretion of EVs from placental cells remains to be fully established. Here, we evaluated the effect of high glucose on proteins associated with the trafficking and release of different populations of EVs from placental cells. BeWo and HTR8/SVneo cells were used as placental models and cultured under 5-mM D-glucose (i.e. control) or 25-mM D-glucose (high glucose). Cell-conditioned media (CCM) and cell lysate were collected after 48 h. Different populations of EVs were isolated from CCM by ultracentrifugation (i.e. pellet 2K-g, pellet 10K-g, and pellet 100K-g) and characterised by Nanoparticle Tracking Analysis. Quantitative proteomic analysis (IDA/SWATH) and multiple reaction monitoring protocols at high resolution (MRM^HR) were developed to quantify 37 proteins related to biogenesis, trafficking/release and recognition/uptake of EVs. High glucose increased the secretion of total EVs across the pellets from BeWo cells, an effect driven mainly by changes in the small EVs concentration in the CCM. Interestingly, no effect of high glucose on HTR8/SVneo cells EVs secretion was observed. High glucose induces changes in proteins associated with vesicle trafficking in BeWo cells, including Heat Shock Protein Family A (Hsp70) Member 9 (HSPA9) and Member 8 (HSPA8). For HTR8/SVneo, altered proteins including prostaglandin F2α receptor regulatory protein (FPRP), RAB5A, RAB35, RAB5B, and RB11B, STAM1 and TSG101. These proteins are associated with the secretion and trafficking of EVs, which could explain in part, changes in the levels of circulating EVs in diabetic pregnancies. Further, we identified that proteins RAB11B, PDCD6IP, STAM, HSPA9, HSPA8, SDCBP, RAB5B, RAB5A, RAB7A and ERAP1 regulate EV release in response to high and low glucose when overexpressed in cells. Interestingly, immunohistochemistry analysis of RAB7A revealed distinct changes in placental tissues obtained from women with normal glucose tolerance (NGT, n = 6) and those with GDM (n = 6), influenced by diet or insulin treatment. High glucose regulation of proteins involved in intercellular dynamics and the trafficking of multivesicular bodies to the plasma membrane in placental cells is relevant in the context of GDM pregnancies.

Extracellular vesicles (EVs) are crucial mediators of cell-to-cell communication in physiological and pathological conditions. Specifically, EVs released from the vasculature into blood were found to be quantitatively and qualitatively different in diseases compared to healthy states. However, our understanding of EVs derived from the lymphatic system is still scarce. In this study, we compared the mRNA and microRNA (miRNA) expression in blood vascular (BEC) and lymphatic (LEC) endothelial cells. After characterization of the EVs by fluorescence-triggered flow cytometry, nanoparticle tracking analysis and cryo-transmission electron microscopy (cryo-TEM) we utilized small RNA-sequencing to characterize miRNA signatures in the EVs and identify cell-type specific miRNAs in BEC and LEC. We found miRNAs specifically enriched in BEC and LEC on the cellular as well as the extracellular vesicle level. Our data provide a solid basis for further functional in vitro and in vivo studies addressing the role of EVs in the blood and lymphatic vasculature.

Extracellular vesicles (EVs) secreted by human-induced pluripotent stem cells (hiPSCs) have great potential as cell-free therapies in various diseases, including prevention of blood–brain barrier senescence and stroke. However, there are still challenges in pre-clinical and clinical use of hiPSC-EVs due to the need for large-scale production of a large quantity. Vertical-Wheel bioreactors (VWBRs) have design features that allow the biomanufacturing of hiPSC-EVs using a scalable aggregate or microcarrier-based culture system under low shear stress. EV secretion by undifferentiated hiPSCs expanded as 3-D aggregates and on Synthemax II microcarriers in VWBRs were investigated. Additionally, two types of EV collection media, mTeSR and HBM, were compared. The hiPSCs were characterized by metabolite and transcriptome analysis as well as EV biogenesis markers. Protein and microRNA cargo were analysed by proteomics and microRNA-seq, respectively. The in vitro functional assays of microglia stimulation and proliferation were conducted. HiPSCs expanded as 3-D aggregates and on microcarriers had comparable cell number, while microcarrier culture had higher glucose consumption, higher glycolysis and lower autophagy gene expression based on mRNA-seq. The microcarrier cultures had at least 17–23 fold higher EV secretion, and EV collection in mTeSR had 2.7–3.7 fold higher yield than HBM medium. Microcarrier culture with mTeSR EV collection had a smaller EV size than other groups, and the cargo was enriched with proteins (proteomics) and miRNAs (microRNA-seq) reducing apoptosis and promoting cell proliferation (e.g. Wnt-related pathways). hiPSC-EVs demonstrated the ability of stimulating proliferation and M2 polarization of microglia in vitro. HiPSC expansion on microcarriers produces much higher yields of EVs than hiPSC aggregates in VWBRs. EV collection in mTeSR increases yield compared to HBM. The biomanufactured EVs from microcarrier culture in mTeSR have exosomal characteristics and are functional in microglia stimulation, which paves the ways for future in vivo anti-aging study.

Blood-derived extracellular vesicles (EVs) hold great therapeutic potential. As blood contains mixed EV populations, it is challenging to study EVs originating from different cells separately. Blood cell concentrates manufactured in blood banks offer an excellent non-invasive source of blood cell-specific EV populations. To study blood cell-specific EVs, we isolated EVs from platelet (TREVs) and red blood cell (EryEVs) concentrates and characterized them using nanoparticle tracking analysis, imaging flow cytometry, electron microscopy and western blot analysis and co-cultured them with peripheral blood mononuclear cells (PBMCs). Our aim was to use imaging flow cytometry to investigate EV interaction with PBMCs as well as study their effects on T-lymphocyte populations to better understand their possible biological functions. As a conclusion, TREVs interacted with PBMCs more than EryEVs. Distinctively, TREVs were uptaken into CD11c+ monocytes rapidly and into CD19+ B-lymphocytes in 24 h. EryEVs were not uptaken into CD11c+ monocytes before the 24-h time point, and they were only seen on the surface of lymphocytes. Neither TREVs nor EryEV were uptaken into CD3+ T-lymphocytes and no effect on T-cell populations was detected. We have previously seen similar differences in targeting PC-3 cancer cells. Further studies are needed to address the functional properties of blood cell concentrate-derived EVs. This study demonstrates that imaging flow cytometry can be used to study the distinctive differences in the interaction and uptake of EVs. Considering our current and previous results, EVs present a new valuable component for the future development of blood-derived therapeutics.

Microvesicles (MVs) are a subtype of extracellular vesicles that can transfer biological information over long distances, affecting normal and pathological processes including skin wound healing. However, the diffusion of MVs into tissues can be impeded by the extracellular matrix (ECM). We investigated the diffusion of dermal wound myofibroblast-derived MVs into the ECM by using hydrogels composed of different ECM molecules such as fibrin, type III collagen and type I collagen that are present during the healing process. Fluorescent MVs mixed with hydrogels were employed to detect MV diffusion using fluorometric methods. Our results showed that MVs specifically bound type I collagen and diffused freely out of fibrin and type III collagen. Further analysis using flow cytometry and specific inhibitors revealed that MVs bind to type I collagen via the α2β1 integrin. These data demonstrate that MV transport depends on the composition of the wound environment.

Human milk extracellular vesicles (HM EVs) are proposed to protect against disease development in infants. This protection could in part be facilitated by the bioactive EV cargo of proteins and RNA. Notably, mothers birth infants of different gestational ages with unique needs, wherein the EV cargo of HM may diverge. We collected HM from lactating mothers within two weeks of a term or preterm birth. Following purification of EVs, proteins and mRNA were extracted for proteomics and sequencing analyses, respectively. Over 2000 protein groups were identified, and over 8000 genes were quantified. The total number of proteins and mRNA did not differ significantly between the two conditions, while functional bioinformatics of differentially expressed cargo indicated enrichment in immunoregulatory cargo for preterm HM EVs. In term HM EVs, significantly upregulated cargo was enriched in metabolism-related functions. Based on gene expression signatures from HM-contained single cell sequencing data, we proposed that a larger portion of preterm HM EVs are secreted by immune cells, whereas term HM EVs contain more signatures of lactocyte epithelial cells. Proposed differences in EV cargo could indicate variation in mother's milk based on infants’ gestational age and provide basis for further functional characterisation.

Extracellular vesicles (EVs) contribute to a wide range of pathological processes including cancer progression, yet the molecular mechanisms underlying their biogenesis remain incompletely characterized. The development of tetraspanin-based pHluorin reporters has enabled the real-time analysis of EV release at the plasma membrane. Here, we employed CD81-pHluorin to investigate mechanisms of EV release in ovarian cancer (OC) cells and report a novel role for the Ca²⁺-permeable transient receptor potential (TRP) channel TRPC3 in EV-mediated communication. We found that specific activation of TRPC3 increased Ca²⁺ signalling in SKOV3 cells and stimulated an immediate increase in EV release. Ca²⁺-stimulants histamine and ionomycin likewise induced EV release, and imaging analysis revealed distinct stimulation-dependent temporal and spatial release dynamics. Interestingly, inhibition of TRPC3 attenuated histamine-stimulated Ca²⁺-entry and EV release, indicating that TRPC3 is likely to act downstream of histamine signalling in EV biogenesis. Furthermore, we found that direct activation of TRPC3 as well as the application of EVs derived from TRPC3-activated cells increased SKOV3 proliferation. Our data provides insights into the molecular mechanisms and dynamics underlying EV release in OC cells, proposing a key role for TRPC3 in EV biogenesis.