Project description:EVs were isolated from primary human aortic endothelial cells (ECs) (+/- IL-1b activation), quantified, and analysed by miRNA transcriptomics and proteomics. Compared to quiescent ECs, activated ECs increased EV release, with miRNA and protein cargo that were related to atherosclerosis pathways. RNA sequencing of EV-treated monocytes and vascular smooth muscle cells (VSMCs) revealed that EVs from activated ECs altered pathways that were pro-inflammatory and atherogenic.
Project description:EVs were isolated from primary human aortic endothelial cells (ECs) (+/- IL-1b activation) grown on transwells, quantified, and analysed by miRNA transcriptomics.
Project description:EVs were isolated from primary human aortic endothelial cells (ECs) (+/- IL-1b activation), quantified, and analysed by miRNA transcriptomics and proteomics.
Project description:BackgroundExtracellular vesicles (EVs) contain bioactive cargo including miRNAs and proteins that are released by cells during cell-cell communication. Endothelial cells (ECs) form the innermost lining of all blood vessels, interfacing with cells in the circulation and vascular wall. It is unknown whether ECs release EVs capable of governing recipient cells within these 2 separate compartments. Given their boundary location, we propose ECs use bidirectional release of distinct EV cargo in quiescent (healthy) and activated (atheroprone) states to communicate with cells within the circulation and blood vessel wall.MethodsEVs were isolated from primary human aortic ECs (plate and transwell grown; ±IL [interleukin]-1β activation), quantified, visualized, and analyzed by miRNA transcriptomics and proteomics. Apical and basolateral EC-EV release was determined by miRNA transfer, total internal reflection fluorescence and electron microscopy. Vascular reprogramming (RNA sequencing) and functional assays were performed on primary human monocytes or smooth muscle cells±EC-EVs.ResultsActivated ECs increased EV release, with miRNA and protein cargo related to atherosclerosis. EV-treated monocytes and smooth muscle cells revealed activated EC-EV altered pathways that were proinflammatory and atherogenic. ECs released more EVs apically, which increased with activation. Apical and basolateral EV cargo contained distinct transcriptomes and proteomes that were altered by EC activation. Notably, activated basolateral EC-EVs displayed greater changes in the EV secretome, with pathways specific to atherosclerosis. In silico analysis determined compartment-specific cargo released by the apical and basolateral surfaces of ECs can reprogram monocytes and smooth muscle cells, respectively, with functional assays and in vivo imaging supporting this concept.ConclusionsDemonstrating that ECs are capable of polarized EV cargo loading and directional EV secretion reveals a novel paradigm for endothelial communication, which may ultimately enhance the design of endothelial-based therapeutics for cardiovascular diseases such as atherosclerosis where ECs are persistently activated.
Project description:Exosomes, important players in cell-cell communication, are small extracellular vesicles of endocytic origin. Although single cells are known to release various kinds of exosomes (referred to as exosomal heterogeneity), very little is known about the mechanisms by which they are produced and released. Here, we established methods of studying exosomal heterogeneity by using polarized epithelial cells and showed that distinct types of small extracellular vesicles (more specifically CD9- and CD63-positive, Annexin I-negative small extracellular vesicles, which we refer to as exosomes herein) are differentially secreted from the apical and basolateral sides of polarized epithelial cells. We also identify GPRC5C (G protein-coupled receptor class C group 5 member C) as an apical-exosome-specific protein. We further demonstrate that basolateral exosome release depends on ceramide, whereas ALIX, an ESCRT (endosomal sorting complexes required for transport)-related protein, not the ESCRT machinery itself, is required for apical exosome release. Thus, two independent machineries, the ALIX–Syntenin1–Syndecan1 machinery (apical side) and the sphingomyelinase-dependent ceramide production machinery (basolateral side), are likely to be responsible for the polarized exosome release from epithelial cells.
Project description:Mycobacterium tuberculosis (Mtb) secretes pathogenicity factors and immunologically active molecules via membrane vesicles. However, nothing is known about the mechanisms involved in mycobacterial vesicle biogenesis. This study investigates molecular determinants of membrane vesicle production in Mtb by analyzing Mtb cells under conditions of high vesicle production: iron limitation and VirR restriction. Ultrastructural analysis showed extensive cell envelope restructuring in association with vesicle release that correlated with downregulation of cell surface lipid biosynthesis and peptidoglycan alterations. Comparative transcriptomics showed common upregulation of the iniBAC operon in association with high vesicle production in Mtb cells. Vesicle production analysis demonstrated that the dynamin-like proteins (DLPs) encoded by this operon, IniA and IniC, are necessary for release of EV by Mtb in culture and in infected macrophages. Isoniazid, a first-line antibiotic, used in tuberculosis treatment, was found to stimulate vesicle release in a DLP-dependent manner. Our results provide a new understanding of the function of mycobacterial DLPs and mechanistic insights into vesicle biogenesis. The findings will enable further understanding of the relevance of Mtb-derived extracellular vesicles in the pathogenesis of tuberculosis and may open new avenues for therapeutic research.
Project description:We report the application of a novel integrated screening strategy to identify lncRNAs that regulate synaptic vesicle release. We identified one of these lncRNAs, which is conserved across mammals, neuron-specific and strictly nuclear. Modulations of this lncRNA influence synaptic vesicle release, presynaptic calcium influx, neurite elongation and neuronal migration. We have characterized the DNA, RNA and protein inteactors of this lncRNA and clarified its involvement in the stabilization of mRNAs for synaptic vesicle proteins.