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Ischemia-induced upregulation of autophagy preludes dysfunctional lysosomal storage and associated synaptic impairments in neurons
Macroautophagy/autophagy is vital for neuronal homeostasis and functions. Accumulating evidence suggest that autophagy is impaired during cerebral ischemia, contributing to neuronal dysfunction and neurodegeneration. However, the outcomes after transient modification in autophagy machinery are not f...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Taylor & Francis
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8205014/ https://www.ncbi.nlm.nih.gov/pubmed/33111641 http://dx.doi.org/10.1080/15548627.2020.1840796 |
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author | Zhang, Xia Wei, Mengping Fan, Jiahui Yan, Weijie Zha, Xu Song, Huimeng Wan, Rongqi Yin, Yanling Wang, Wei |
author_facet | Zhang, Xia Wei, Mengping Fan, Jiahui Yan, Weijie Zha, Xu Song, Huimeng Wan, Rongqi Yin, Yanling Wang, Wei |
author_sort | Zhang, Xia |
collection | PubMed |
description | Macroautophagy/autophagy is vital for neuronal homeostasis and functions. Accumulating evidence suggest that autophagy is impaired during cerebral ischemia, contributing to neuronal dysfunction and neurodegeneration. However, the outcomes after transient modification in autophagy machinery are not fully understood. This study investigated the effects of ischemic stress on autophagy and synaptic structures using a rat model of oxygen-glucose deprivation (OGD) in hippocampal neurons and a mouse model of middle cerebral artery occlusion (MCAO). Upon acute ischemia, an initial autophagy modification occurred in an upregulation manner. Following, the number of lysosomes increased, as well as lysosomal volume, indicating dysfunctional lysosomal storage. These changes were prevented by inhibiting autophagy via 3-methyladenine (3-MA) treatment or ATG7 (autophagy related 7) knockdown, or were mimicked by rapamycin (RAPA), a known activator of autophagy. This suggests that dysfunctional lysosomal storage is associated with the early burst of autophagy. Dysfunctional lysosomal storage contributed to autophagy dysfunction because the basal level of MTOR-dependent lysosomal biogenesis in the reperfusion was not sufficient to clear undegraded cargoes after transient autophagy upregulation. Further investigation revealed that impairment of synaptic ultra-structures, accompanied by dysfunctional lysosomal storage, may result from a failure in dynamic turnover of synaptic proteins. This indicates a vital role of autophagy-lysosomal machinery in the maintenance of synaptic structures. This study supports previous evidence that dysfunctional lysosomal storage may occur following the upregulation of autophagy in neurons. Appropriate autophagosome-lysosomal functioning is vital for maintenance of neuronal synaptic function and impacts more than the few known synaptic proteins. Abbreviations: 3-MA: 3-methyladenine; ACTB: actin beta; AD: Alzheimer disease; ALR: autophagic lysosome reformation; ATG7: autophagy related 7; CTSB: cathepsin B; CTSD: cathepsin D; DAPI: 4ʹ,6-diamidino-2-phenylindole; DEGs: differentially expressed genes; DMEM: Dulbecco’s modified Eagle’s medium; DMSO: dimethyl sulfoxide; GO: Gene Ontology; HBSS: Hanks’ balanced salt solution; HPCA: hippocalcin; i.c.v: intracerebroventricular; KEGG: kyoto encyclopedia of genes and genomes; LAMP1: lysosomal-associated membrane protein 1; MAP1LC3B/LC3: microtubule-associated protein 1 light chain 3 beta; LSDs: lysosomal storage disorders; MAP2: microtubule-associated protein 2; MCAO: middle cerebral artery occlusion; mCTSB: mature CTSB; mCTSD: mature CTSD; MOI: multiplicity of infection; MTOR: mechanistic target of rapamycin kinase; OGD/R: oxygen-glucose deprivation/reoxygenation; PBS: phosphate-buffered saline; PRKAA/AMPKα: protein kinase AMP-activated catalytic subunit alpha; proCTSD: pro-cathepsin D; RAPA: rapamycin; RNA-seq: RNA sequencing; RPS6KB/p70S6K: ribosomal protein S6 kinase; SDS-PAGE: sodium dodecyl sulfate-polyacrylamide gel electrophoresis; SIM: Structured Illumination Microscopy; SNAP25: synaptosomal-associated protein 25; SQSTM1/p62: sequestosome 1; SYN1: synapsin I; SYT1: synaptotagmin I; TBST: tris-buffered saline Tween-20; TEM: transmission electron microscopy; TFEB: transcription factor EB; tMCAO: transient middle cerebral artery occlusion; TTC: 2,3,5-triphenyltetrazolium chloride; TUBB3: tubulin, beta 3 class III. |
format | Online Article Text |
id | pubmed-8205014 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | Taylor & Francis |
record_format | MEDLINE/PubMed |
spelling | pubmed-82050142021-06-24 Ischemia-induced upregulation of autophagy preludes dysfunctional lysosomal storage and associated synaptic impairments in neurons Zhang, Xia Wei, Mengping Fan, Jiahui Yan, Weijie Zha, Xu Song, Huimeng Wan, Rongqi Yin, Yanling Wang, Wei Autophagy Research Paper Macroautophagy/autophagy is vital for neuronal homeostasis and functions. Accumulating evidence suggest that autophagy is impaired during cerebral ischemia, contributing to neuronal dysfunction and neurodegeneration. However, the outcomes after transient modification in autophagy machinery are not fully understood. This study investigated the effects of ischemic stress on autophagy and synaptic structures using a rat model of oxygen-glucose deprivation (OGD) in hippocampal neurons and a mouse model of middle cerebral artery occlusion (MCAO). Upon acute ischemia, an initial autophagy modification occurred in an upregulation manner. Following, the number of lysosomes increased, as well as lysosomal volume, indicating dysfunctional lysosomal storage. These changes were prevented by inhibiting autophagy via 3-methyladenine (3-MA) treatment or ATG7 (autophagy related 7) knockdown, or were mimicked by rapamycin (RAPA), a known activator of autophagy. This suggests that dysfunctional lysosomal storage is associated with the early burst of autophagy. Dysfunctional lysosomal storage contributed to autophagy dysfunction because the basal level of MTOR-dependent lysosomal biogenesis in the reperfusion was not sufficient to clear undegraded cargoes after transient autophagy upregulation. Further investigation revealed that impairment of synaptic ultra-structures, accompanied by dysfunctional lysosomal storage, may result from a failure in dynamic turnover of synaptic proteins. This indicates a vital role of autophagy-lysosomal machinery in the maintenance of synaptic structures. This study supports previous evidence that dysfunctional lysosomal storage may occur following the upregulation of autophagy in neurons. Appropriate autophagosome-lysosomal functioning is vital for maintenance of neuronal synaptic function and impacts more than the few known synaptic proteins. Abbreviations: 3-MA: 3-methyladenine; ACTB: actin beta; AD: Alzheimer disease; ALR: autophagic lysosome reformation; ATG7: autophagy related 7; CTSB: cathepsin B; CTSD: cathepsin D; DAPI: 4ʹ,6-diamidino-2-phenylindole; DEGs: differentially expressed genes; DMEM: Dulbecco’s modified Eagle’s medium; DMSO: dimethyl sulfoxide; GO: Gene Ontology; HBSS: Hanks’ balanced salt solution; HPCA: hippocalcin; i.c.v: intracerebroventricular; KEGG: kyoto encyclopedia of genes and genomes; LAMP1: lysosomal-associated membrane protein 1; MAP1LC3B/LC3: microtubule-associated protein 1 light chain 3 beta; LSDs: lysosomal storage disorders; MAP2: microtubule-associated protein 2; MCAO: middle cerebral artery occlusion; mCTSB: mature CTSB; mCTSD: mature CTSD; MOI: multiplicity of infection; MTOR: mechanistic target of rapamycin kinase; OGD/R: oxygen-glucose deprivation/reoxygenation; PBS: phosphate-buffered saline; PRKAA/AMPKα: protein kinase AMP-activated catalytic subunit alpha; proCTSD: pro-cathepsin D; RAPA: rapamycin; RNA-seq: RNA sequencing; RPS6KB/p70S6K: ribosomal protein S6 kinase; SDS-PAGE: sodium dodecyl sulfate-polyacrylamide gel electrophoresis; SIM: Structured Illumination Microscopy; SNAP25: synaptosomal-associated protein 25; SQSTM1/p62: sequestosome 1; SYN1: synapsin I; SYT1: synaptotagmin I; TBST: tris-buffered saline Tween-20; TEM: transmission electron microscopy; TFEB: transcription factor EB; tMCAO: transient middle cerebral artery occlusion; TTC: 2,3,5-triphenyltetrazolium chloride; TUBB3: tubulin, beta 3 class III. Taylor & Francis 2020-11-12 /pmc/articles/PMC8205014/ /pubmed/33111641 http://dx.doi.org/10.1080/15548627.2020.1840796 Text en © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. https://creativecommons.org/licenses/by-nc-nd/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-nc-nd/4.0/ (https://creativecommons.org/licenses/by-nc-nd/4.0/) ), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way. |
spellingShingle | Research Paper Zhang, Xia Wei, Mengping Fan, Jiahui Yan, Weijie Zha, Xu Song, Huimeng Wan, Rongqi Yin, Yanling Wang, Wei Ischemia-induced upregulation of autophagy preludes dysfunctional lysosomal storage and associated synaptic impairments in neurons |
title | Ischemia-induced upregulation of autophagy preludes dysfunctional lysosomal storage and associated synaptic impairments in neurons |
title_full | Ischemia-induced upregulation of autophagy preludes dysfunctional lysosomal storage and associated synaptic impairments in neurons |
title_fullStr | Ischemia-induced upregulation of autophagy preludes dysfunctional lysosomal storage and associated synaptic impairments in neurons |
title_full_unstemmed | Ischemia-induced upregulation of autophagy preludes dysfunctional lysosomal storage and associated synaptic impairments in neurons |
title_short | Ischemia-induced upregulation of autophagy preludes dysfunctional lysosomal storage and associated synaptic impairments in neurons |
title_sort | ischemia-induced upregulation of autophagy preludes dysfunctional lysosomal storage and associated synaptic impairments in neurons |
topic | Research Paper |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8205014/ https://www.ncbi.nlm.nih.gov/pubmed/33111641 http://dx.doi.org/10.1080/15548627.2020.1840796 |
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