Ultrastructural and dynamic studies of the endosomal compartment in Down syndrome
Abstract Enlarged early endosomes have been visualized in Alzheimer’s disease (AD) and Down syndrome (DS) using conventional confocal microscopy at a resolution corresponding to endosomal size (hundreds of nm). In order to overtake the diffraction limit, we used super-resolution structured illuminat...
| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2020-06-01
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| Series: | Acta Neuropathologica Communications |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s40478-020-00956-z |
| _version_ | 1819157964603260928 |
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| author | Alexandra Botté Jeanne Lainé Laura Xicota Xavier Heiligenstein Gaëlle Fontaine Amal Kasri Isabelle Rivals Pollyanna Goh Orestis Faklaris Jack-Christophe Cossec Etienne Morel Anne-Sophie Rebillat Dean Nizetic Graça Raposo Marie-Claude Potier |
| author_facet | Alexandra Botté Jeanne Lainé Laura Xicota Xavier Heiligenstein Gaëlle Fontaine Amal Kasri Isabelle Rivals Pollyanna Goh Orestis Faklaris Jack-Christophe Cossec Etienne Morel Anne-Sophie Rebillat Dean Nizetic Graça Raposo Marie-Claude Potier |
| author_sort | Alexandra Botté |
| collection | DOAJ |
| description | Abstract Enlarged early endosomes have been visualized in Alzheimer’s disease (AD) and Down syndrome (DS) using conventional confocal microscopy at a resolution corresponding to endosomal size (hundreds of nm). In order to overtake the diffraction limit, we used super-resolution structured illumination microscopy (SR-SIM) and transmission electron microscopies (TEM) to analyze the early endosomal compartment in DS. By immunofluorescence and confocal microscopy, we confirmed that the volume of Early Endosome Antigen 1 (EEA1)-positive puncta was 13–19% larger in fibroblasts and iPSC-derived neurons from individuals with DS, and in basal forebrain cholinergic neurons (BFCN) of the Ts65Dn mice modelling DS. However, EEA1-positive structures imaged by TEM or SR-SIM after chemical fixation had a normal size but appeared clustered. In order to disentangle these discrepancies, we imaged optimally preserved High Pressure Freezing (HPF)-vitrified DS fibroblasts by TEM and found that early endosomes were 75% denser but remained normal-sized. RNA sequencing of DS and euploid fibroblasts revealed a subgroup of differentially-expressed genes related to cargo sorting at multivesicular bodies (MVBs). We thus studied the dynamics of endocytosis, recycling and MVB-dependent degradation in DS fibroblasts. We found no change in endocytosis, increased recycling and delayed degradation, suggesting a “traffic jam” in the endosomal compartment. Finally, we show that the phosphoinositide PI (3) P, involved in early endosome fusion, is decreased in DS fibroblasts, unveiling a new mechanism for endosomal dysfunctions in DS and a target for pharmacotherapy. |
| first_indexed | 2024-12-22T16:17:08Z |
| format | Article |
| id | doaj.art-26fd67e10b014d1ab8afbad372ac26f6 |
| institution | Directory Open Access Journal |
| issn | 2051-5960 |
| language | English |
| last_indexed | 2024-12-22T16:17:08Z |
| publishDate | 2020-06-01 |
| publisher | BMC |
| record_format | Article |
| series | Acta Neuropathologica Communications |
| spelling | doaj.art-26fd67e10b014d1ab8afbad372ac26f62022-12-21T18:20:21ZengBMCActa Neuropathologica Communications2051-59602020-06-018112210.1186/s40478-020-00956-zUltrastructural and dynamic studies of the endosomal compartment in Down syndromeAlexandra Botté0Jeanne Lainé1Laura Xicota2Xavier Heiligenstein3Gaëlle Fontaine4Amal Kasri5Isabelle Rivals6Pollyanna Goh7Orestis Faklaris8Jack-Christophe Cossec9Etienne Morel10Anne-Sophie Rebillat11Dean Nizetic12Graça Raposo13Marie-Claude Potier14Paris Brain Institute (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-SalpêtrièreParis Brain Institute (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-SalpêtrièreParis Brain Institute (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-SalpêtrièreCryoCapCellParis Brain Institute (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-SalpêtrièreParis Brain Institute (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-SalpêtrièreEquipe de Statistique Appliquée, ESPCI Paris, PSL Research University, UMRS 1158The Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary, University of LondonImagoSeine Imaging Core Facility, Institut Jacques Monod, CNRS UMR7592, Université Paris-Diderot, Sorbonne Paris CitéParis Brain Institute (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-SalpêtrièreInstitut Necker-Enfants Malades (INEM), INSERM U1151 CNRS UMR 8253, Université Paris Descartes-Sorbonne Paris CitéInstitut Jérôme LejeuneThe Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary, University of LondonInstitut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane CompartmentsParis Brain Institute (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-SalpêtrièreAbstract Enlarged early endosomes have been visualized in Alzheimer’s disease (AD) and Down syndrome (DS) using conventional confocal microscopy at a resolution corresponding to endosomal size (hundreds of nm). In order to overtake the diffraction limit, we used super-resolution structured illumination microscopy (SR-SIM) and transmission electron microscopies (TEM) to analyze the early endosomal compartment in DS. By immunofluorescence and confocal microscopy, we confirmed that the volume of Early Endosome Antigen 1 (EEA1)-positive puncta was 13–19% larger in fibroblasts and iPSC-derived neurons from individuals with DS, and in basal forebrain cholinergic neurons (BFCN) of the Ts65Dn mice modelling DS. However, EEA1-positive structures imaged by TEM or SR-SIM after chemical fixation had a normal size but appeared clustered. In order to disentangle these discrepancies, we imaged optimally preserved High Pressure Freezing (HPF)-vitrified DS fibroblasts by TEM and found that early endosomes were 75% denser but remained normal-sized. RNA sequencing of DS and euploid fibroblasts revealed a subgroup of differentially-expressed genes related to cargo sorting at multivesicular bodies (MVBs). We thus studied the dynamics of endocytosis, recycling and MVB-dependent degradation in DS fibroblasts. We found no change in endocytosis, increased recycling and delayed degradation, suggesting a “traffic jam” in the endosomal compartment. Finally, we show that the phosphoinositide PI (3) P, involved in early endosome fusion, is decreased in DS fibroblasts, unveiling a new mechanism for endosomal dysfunctions in DS and a target for pharmacotherapy.http://link.springer.com/article/10.1186/s40478-020-00956-zDown syndromeAlzheimer’s diseaseEarly endosomesEndocytosisElectron microscopySuper-resolution microscopy |
| spellingShingle | Alexandra Botté Jeanne Lainé Laura Xicota Xavier Heiligenstein Gaëlle Fontaine Amal Kasri Isabelle Rivals Pollyanna Goh Orestis Faklaris Jack-Christophe Cossec Etienne Morel Anne-Sophie Rebillat Dean Nizetic Graça Raposo Marie-Claude Potier Ultrastructural and dynamic studies of the endosomal compartment in Down syndrome Acta Neuropathologica Communications Down syndrome Alzheimer’s disease Early endosomes Endocytosis Electron microscopy Super-resolution microscopy |
| title | Ultrastructural and dynamic studies of the endosomal compartment in Down syndrome |
| title_full | Ultrastructural and dynamic studies of the endosomal compartment in Down syndrome |
| title_fullStr | Ultrastructural and dynamic studies of the endosomal compartment in Down syndrome |
| title_full_unstemmed | Ultrastructural and dynamic studies of the endosomal compartment in Down syndrome |
| title_short | Ultrastructural and dynamic studies of the endosomal compartment in Down syndrome |
| title_sort | ultrastructural and dynamic studies of the endosomal compartment in down syndrome |
| topic | Down syndrome Alzheimer’s disease Early endosomes Endocytosis Electron microscopy Super-resolution microscopy |
| url | http://link.springer.com/article/10.1186/s40478-020-00956-z |
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