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Corso G, Heusermann W, Trojer D, Görgens A, Steib E, Voshol J, Graff A, Genoud C, Lee Y, Hean J, Nordin JZ, Wiklander OPB, El Andaloussi S, Meisner-Kober N. Systematic characterization of extracellular vesicle sorting domains and quantification at the single molecule - single vesicle level by fluorescence correlation spectroscopy and single particle imaging. J Extracell Vesicles 2019; 8:1663043. [PMID: 31579435 PMCID: PMC6758720 DOI: 10.1080/20013078.2019.1663043] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 08/20/2019] [Accepted: 08/21/2019] [Indexed: 02/07/2023] Open
Abstract
Extracellular vesicles (EV) convey biological information by transmitting macromolecules between cells and tissues and are of great promise as pharmaceutical nanocarriers, and as therapeutic per se. Strategies for customizing the EV surface and cargo are being developed to enable their tracking, visualization, loading with pharmaceutical agents and decoration of the surface with tissue targeting ligands. While much progress has been made in the engineering of EVs, an exhaustive comparative analysis of the most commonly exploited EV-associated proteins, as well as a quantification at the molecular level are lacking. Here, we selected 12 EV-related proteins based on MS-proteomics data for comparative quantification of their EV engineering potential. All proteins were expressed with fluorescent protein (FP) tags in EV-producing cells; both parent cells as well as the recovered vesicles were characterized biochemically and biophysically. Using Fluorescence Correlation Spectroscopy (FCS) we quantified the number of FP-tagged molecules per vesicle. We observed different loading efficiencies and specificities for the different proteins into EVs. For the candidates showing the highest loading efficiency in terms of engineering, the molecular levels in the vesicles did not exceed ca 40-60 fluorescent proteins per vesicle upon transient overexpression in the cells. Some of the GFP-tagged EV reporters showed quenched fluorescence and were either non-vesicular, despite co-purification with EVs, or comprised a significant fraction of truncated GFP. The co-expression of each target protein with CD63 was further quantified by widefield and confocal imaging of single vesicles after double transfection of parent cells. In summary, we provide a quantitative comparison for the most commonly used sorting proteins for bioengineering of EVs and introduce a set of biophysical techniques for straightforward quantitative and qualitative characterization of fluorescent EVs to link single vesicle analysis with single molecule quantification.
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Affiliation(s)
- Giulia Corso
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Wolf Heusermann
- Novartis Institutes for Biomedical Research, Basel, Switzerland.,Imaging Core Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - Dominic Trojer
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - André Görgens
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.,Institute for Transfusion Medicine, University Hospital Essen, Essen, Germany
| | - Emmanuelle Steib
- Novartis Institutes for Biomedical Research, Basel, Switzerland.,Department of Cell Biology, Sciences III, University of Geneva, Geneva Switzerland
| | - Johannes Voshol
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Alexandra Graff
- Facility for advanced imaging and microscopy, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Christel Genoud
- Facility for advanced imaging and microscopy, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Yi Lee
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Cancer and Stratified Oncology 5, Astar Genome Institute of Singapore, Singapore
| | - Justin Hean
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Joel Z Nordin
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | | | - Nicole Meisner-Kober
- Novartis Institutes for Biomedical Research, Basel, Switzerland.,Department of Biosciences, University of Salzburg, Salzburg, Austria
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Heusermann W, Hean J, Trojer D, Steib E, von Bueren S, Graff-Meyer A, Genoud C, Martin K, Pizzato N, Voshol J, Morrissey DV, Andaloussi SEL, Wood MJ, Meisner-Kober NC. Exosomes surf on filopodia to enter cells at endocytic hot spots, traffic within endosomes, and are targeted to the ER. J Cell Biol 2017; 213:173-84. [PMID: 27114500 PMCID: PMC5084269 DOI: 10.1083/jcb.201506084] [Citation(s) in RCA: 288] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 03/09/2016] [Indexed: 12/19/2022] Open
Abstract
Exosomes are nanovesicles released by virtually all cells, which act as intercellular messengers by transfer of protein, lipid, and RNA cargo. Their quantitative efficiency, routes of cell uptake, and subcellular fate within recipient cells remain elusive. We quantitatively characterize exosome cell uptake, which saturates with dose and time and reaches near 100% transduction efficiency at picomolar concentrations. Highly reminiscent of pathogenic bacteria and viruses, exosomes are recruited as single vesicles to the cell body by surfing on filopodia as well as filopodia grabbing and pulling motions to reach endocytic hot spots at the filopodial base. After internalization, exosomes shuttle within endocytic vesicles to scan the endoplasmic reticulum before being sorted into the lysosome as their final intracellular destination. Our data quantify and explain the efficiency of exosome internalization by recipient cells, establish a new parallel between exosome and virus host cell interaction, and suggest unanticipated routes of subcellular cargo delivery.
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Affiliation(s)
- Wolf Heusermann
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | - Justin Hean
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, England, UK
| | - Dominic Trojer
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | - Emmanuelle Steib
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | - Stefan von Bueren
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | | | - Christel Genoud
- Friedrich-Miescher Institute for Biomedical Research, CH-4000 Basel, Switzerland
| | - Katrin Martin
- Department of Biomedicine, University of Basel, CH-4058 Basel, Switzerland
| | - Nicolas Pizzato
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | - Johannes Voshol
- Novartis Institutes for Biomedical Research, CH-4000 Basel, Switzerland
| | | | - Samir E L Andaloussi
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, England, UK Department of Laboratory Medicine, Karolinska Institutet, SE-141 86 Huddinge, Sweden
| | - Matthew J Wood
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, England, UK
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Stalder L, Heusermann W, Sokol L, Trojer D, Wirz J, Hean J, Fritzsche A, Aeschimann F, Pfanzagl V, Basselet P, Weiler J, Hintersteiner M, Morrissey DV, Meisner-Kober NC. The rough endoplasmatic reticulum is a central nucleation site of siRNA-mediated RNA silencing. EMBO J 2013; 32:1115-27. [PMID: 23511973 PMCID: PMC3630355 DOI: 10.1038/emboj.2013.52] [Citation(s) in RCA: 168] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 01/31/2013] [Indexed: 12/24/2022] Open
Abstract
Despite progress in mechanistic understanding of the RNA interference (RNAi) pathways, the subcellular sites of RNA silencing remain under debate. Here we show that loading of lipid-transfected siRNAs and endogenous microRNAs (miRNA) into RISC (RNA-induced silencing complexes), encounter of the target mRNA, and Ago2-mediated mRNA slicing in mammalian cells are nucleated at the rough endoplasmic reticulum (rER). Although the major RNAi pathway proteins are found in most subcellular compartments, the miRNA- and siRNA-loaded Ago2 populations co-sediment almost exclusively with the rER membranes, together with the RISC loading complex (RLC) factors Dicer, TAR RNA binding protein (TRBP) and protein activator of the interferon-induced protein kinase (PACT). Fractionation and membrane co-immune precipitations further confirm that siRNA-loaded Ago2 physically associates with the cytosolic side of the rER membrane. Additionally, RLC-associated double-stranded siRNA, diagnostic of RISC loading, and RISC-mediated mRNA cleavage products exclusively co-sediment with rER. Finally, we identify TRBP and PACT as key factors anchoring RISC to ER membranes in an RNA-independent manner. Together, our findings demonstrate that the outer rER membrane is a central nucleation site of siRNA-mediated RNA silencing.
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Affiliation(s)
- Lukas Stalder
- Novartis Institutes for Biomedical Research, NIBR Biologics Center, RNAi Therapeutics, Basel 4000, Switzerland.
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