1
|
de Rond L, Libregts SFWM, Rikkert LG, Hau CM, van der Pol E, Nieuwland R, van Leeuwen TG, Coumans FAW. Refractive index to evaluate staining specificity of extracellular vesicles by flow cytometry. J Extracell Vesicles 2019; 8:1643671. [PMID: 31489142 PMCID: PMC6713200 DOI: 10.1080/20013078.2019.1643671] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [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: 03/15/2019] [Revised: 06/06/2019] [Accepted: 07/11/2019] [Indexed: 12/12/2022] Open
Abstract
Extracellular vesicles (EVs) in plasma are commonly identified by staining with antibodies and generic dyes, but the specificity of antibodies and dyes to stain EVs is often unknown. Previously, we showed that platelet-depleted platelet concentrate contains two populations of particles >200 nm, one population with a refractive index (RI) < 1.42 that included the majority of EVs, and a second population with an RI > 1.42, which was thought to include lipoproteins. In this study, we investigated whether EVs can be distinguished from lipoproteins by the RI and whether the RI can be used to determine the specificity of antibodies and generic dyes used to stain plasma EVs. EVs and lipoproteins present in platelet-depleted platelet concentrate were separated by density gradient centrifugation. The density fractions were analyzed by Western blot and transmission electron microscopy, the RI of particles was determined by Flow-SR. The RI was used to evaluate the staining specificity of an antibody against platelet glycoprotein IIIa (CD61) and the commonly used generic dyes calcein AM, calcein violet, di-8-ANEPPS, and lactadherin in plasma. After density gradient centrifugation, EV-enriched fractions (1.12 to 1.07 g/mL) contained the highest concentration of particles with an RI < 1.42, and the lipoprotein-enriched fractions (1.04 to 1.03 g/mL) contained the highest concentration of particles with an RI > 1.42. Application of the RI showed that CD61-APC had the highest staining specificity for EVs, followed by lactadherin and calcein violet. Di-8-ANEPPS stained mainly lipoproteins and calcein AM stained neither lipoproteins nor EVs. Taken together, the RI can be used to distinguish EVs and lipoproteins, and thus allows evaluation of the specificity of antibodies and generic dyes to stain EVs.
Collapse
Affiliation(s)
- L de Rond
- Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Laboratory Experimental Clinical Chemistry, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Vesicle Observation Center, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - S F W M Libregts
- Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - L G Rikkert
- Laboratory Experimental Clinical Chemistry, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Vesicle Observation Center, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Medical Cell BioPhysics, University of Twente, Enschede, The Netherlands
| | - C M Hau
- Laboratory Experimental Clinical Chemistry, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Vesicle Observation Center, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - E van der Pol
- Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Laboratory Experimental Clinical Chemistry, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Vesicle Observation Center, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - R Nieuwland
- Laboratory Experimental Clinical Chemistry, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Vesicle Observation Center, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - T G van Leeuwen
- Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Vesicle Observation Center, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - F A W Coumans
- Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Laboratory Experimental Clinical Chemistry, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Vesicle Observation Center, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
2
|
Boere J, van de Lest CHA, de Grauw JC, Plomp SGM, Libregts SFWM, Arkesteijn GJA, Malda J, Wauben MHM, van Weeren PR. Extracellular vesicles in synovial fluid from juvenile horses: No age-related changes in the quantitative profile. Vet J 2018; 244:91-93. [PMID: 30825901 DOI: 10.1016/j.tvjl.2018.12.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 09/29/2018] [Accepted: 12/07/2018] [Indexed: 11/19/2022]
Abstract
Extracellular vesicle (EV) concentration, characteristics and function in equine synovial fluid (SF) during normal growth and development has not previously been studied. Isolation of EVs was performed in SF from three healthy foals and two adult horses by differential ultracentrifugation (10,000g and 200,000g); EVs were purified by sucrose density gradient floatation and analysed by high-resolution flow cytometry (FCM), buoyant density and western blotting. Additionally, repeated biomarker analysis of sulphated glycosaminoglycans (GAG), matrix metalloproteinase (MMP), C-terminal crosslinked telopeptide type II collagen (CTX-II), collagenase cleaved neopeptide type II collagen (C2C) was performed in SF from 10 foals and six adult horses. In contrast with the quantitative EV profile, the biomarker profile in SF from juvenile joints was substantially different from that in SF from adult animals. However, there were qualitative differences in the high-resolution FCM scatter plots. Future in-depth functional analyses may reveal differences between juvenile and mature EVs in SF.
Collapse
Affiliation(s)
- J Boere
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584CM Utrecht, The Netherlands
| | - C H A van de Lest
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584CM Utrecht, The Netherlands; Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 2, 3584CM Utrecht, The Netherlands
| | - J C de Grauw
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584CM Utrecht, The Netherlands
| | - S G M Plomp
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584CM Utrecht, The Netherlands
| | - S F W M Libregts
- Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 2, 3584CM Utrecht, The Netherlands
| | - G J A Arkesteijn
- Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 2, 3584CM Utrecht, The Netherlands; Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584CM Utrecht, The Netherlands
| | - J Malda
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584CM Utrecht, The Netherlands; Department of Orthopaedics, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - M H M Wauben
- Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 2, 3584CM Utrecht, The Netherlands
| | - P R van Weeren
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584CM Utrecht, The Netherlands.
| |
Collapse
|
3
|
Libregts SFWM, Arkesteijn GJA, Németh A, Nolte-'t Hoen ENM, Wauben MHM. Flow cytometric analysis of extracellular vesicle subsets in plasma: impact of swarm by particles of non-interest. J Thromb Haemost 2018; 16:1423-1436. [PMID: 29781099 DOI: 10.1111/jth.14154] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Indexed: 12/16/2022]
Abstract
Essentials Extracellular vesicles (EVs) in biological fluids are promising biomarkers for disease. Fluorescence-based flow cytometric analysis is suitable to detect low abundant EV subsets. Particles of non-interest can induce false-positive light scatter and fluorescent signals. Interference of particles of non-interest can be monitored by analyzing serial dilutions. SUMMARY Background Extracellular vesicles (EVs) in plasma are increasingly being recognized as potential biomarkers. EV analysis for diagnostic purposes should be robust and should allow analysis of EV subsets with a wide range of abundance and in a large number of patient samples. Flow cytometry offers possibilities to meet these criteria, as it allows multiparameter analysis of individual EVs. However, analysis of plasma EVs is challenging, because of their size and heterogeneity, and the presence of other submicrometer-sized particles in plasma that could interfere with EV analysis. Objectives To explore whether fluorescence-based flow cytometric analysis of EV subsets is suitable when the EVs of interest are present in low abundance in a background of non-labeled or differently labeled EVs and particles. Methods Fluorescently labeled EVs of interest were spiked at different ratios in full plasma, purified plasma components, or (non-)fluorescent polystyrene beads, and subsequently analyzed by flow cytometry with fluorescence threshold triggering. Results We found that light scatter detection of low-abundance or rare EV subsets during fluorescence threshold triggering was severely affected by particles of non-interest, owing to coincidence and swarming. Importantly, we show that interfering particles labeled with different fluorophores induced false-positive fluorescent signals on the particles of interest. These unwanted effects could only be discerned and controlled by performing serial dilutions and analyzing light scatter and fluorescence parameters. Conclusions We demonstrate how particles of non-interest in plasma can impact on the light scatter and fluorescence detection of low-abundance EVs of interest during fluorescence-based flow cytometric analysis, and provide a means to prevent erroneous data interpretation.
Collapse
Affiliation(s)
- S F W M Libregts
- Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - G J A Arkesteijn
- Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - A Németh
- Department of Genetics, Cell- and Immunobiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - E N M Nolte-'t Hoen
- Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - M H M Wauben
- Department of Biochemistry & Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| |
Collapse
|