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Lenz M, Eichler A, Kruse P, Galanis C, Kleidonas D, Andrieux G, Boerries M, Jedlicka P, Müller U, Deller T, Vlachos A. The Amyloid Precursor Protein Regulates Synaptic Transmission at Medial Perforant Path Synapses. J Neurosci 2023; 43:5290-5304. [PMID: 37369586 PMCID: PMC10359033 DOI: 10.1523/jneurosci.1824-22.2023] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 05/20/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
The perforant path provides the primary cortical excitatory input to the hippocampus. Because of its important role in information processing and coding, entorhinal projections to the dentate gyrus have been studied in considerable detail. Nevertheless, synaptic transmission between individual connected pairs of entorhinal stellate cells and dentate granule cells remains to be characterized. Here, we have used mouse organotypic entorhino-hippocampal tissue cultures of either sex, in which the entorhinal cortex (EC) to dentate granule cell (GC; EC-GC) projection is present, and EC-GC pairs can be studied using whole-cell patch-clamp recordings. By using cultures of wild-type mice, the properties of EC-GC synapses formed by afferents from the lateral and medial entorhinal cortex were compared, and differences in short-term plasticity were identified. As the perforant path is severely affected in Alzheimer's disease, we used tissue cultures of amyloid precursor protein (APP)-deficient mice to examine the role of APP at this synapse. APP deficiency altered excitatory neurotransmission at medial perforant path synapses, which was accompanied by transcriptomic and ultrastructural changes. Moreover, presynaptic but not postsynaptic APP deletion through the local injection of Cre-expressing adeno-associated viruses in conditional APPflox/flox tissue cultures increased the neurotransmission efficacy at perforant path synapses. In summary, these data suggest a physiological role for presynaptic APP at medial perforant path synapses that may be adversely affected under altered APP processing conditions.SIGNIFICANCE STATEMENT The hippocampus receives input from the entorhinal cortex via the perforant path. These projections to hippocampal dentate granule cells are of utmost importance for learning and memory formation. Although there is detailed knowledge about perforant path projections, the functional synaptic properties at the level of individual connected pairs of neurons are not well understood. In this study, we investigated the role of APP in mediating functional properties and transmission rules in individually connected neurons using paired whole-cell patch-clamp recordings and genetic tools in organotypic tissue cultures. Our results show that presynaptic APP expression limits excitatory neurotransmission via the perforant path, which could be compromised in pathologic conditions such as Alzheimer's disease.
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Affiliation(s)
- Maximilian Lenz
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Hannover Medical School, Institute of Neuroanatomy and Cell Biology, 30625 Hannover, Germany
| | - Amelie Eichler
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Pia Kruse
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Christos Galanis
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Dimitrios Kleidonas
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Geoffroy Andrieux
- Institute of Medical Bioinformatics and Systems Medicine, Medical Center, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Melanie Boerries
- Institute of Medical Bioinformatics and Systems Medicine, Medical Center, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- German Cancer Consortium, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Peter Jedlicka
- Interdisciplinary Centre for 3Rs in Animal Research, Faculty of Medicine, Justus-Liebig-University, 35392 Giessen, Germany
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany
- Frankfurt Institute for Advanced Studies, 60438 Frankfurt am Main, Germany
| | - Ulrike Müller
- Institute of Pharmacy and Molecular Biotechnology, Functional Genomics, Ruprecht-Karls University Heidelberg, 69120 Heidelberg, Germany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany
| | - Andreas Vlachos
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Center for Basics in Neuromodulation, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Center BrainLinks-BrainTools, University of Freiburg, 79104 Freiburg, Germany
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Erdinger S, Amrein I, Back M, Ludewig S, Korte M, von Engelhardt J, Wolfer DP, Müller UC. Lack of APLP1 leads to subtle alterations in neuronal morphology but does not affect learning and memory. Front Mol Neurosci 2022; 15:1028836. [DOI: 10.3389/fnmol.2022.1028836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 10/11/2022] [Indexed: 11/13/2022] Open
Abstract
The amyloid precursor protein APP plays a crucial role in Alzheimer pathogenesis. Its physiological functions, however, are only beginning to be unraveled. APP belongs to a small gene family, including besides APP the closely related amyloid precursor-like proteins APLP1 and APLP2, that all constitute synaptic adhesion proteins. While APP and APLP2 are ubiquitously expressed, APLP1 is specific for the nervous system. Previous genetic studies, including combined knockouts of several family members, pointed towards a unique role for APLP1, as only APP/APLP1 double knockouts were viable. We now examined brain and neuronal morphology in APLP1 single knockout (KO) animals, that have to date not been studied in detail. Here, we report that APLP1-KO mice show normal spine density in hippocampal CA1 pyramidal cells and subtle alterations in dendritic complexity. Extracellular field recordings revealed normal basal synaptic transmission and no alterations in synaptic plasticity (LTP). Further, behavioral studies revealed in APLP1-KO mice a small deficit in motor function and reduced diurnal locomotor activity, while learning and memory were not affected by the loss of APLP1. In summary, our study indicates that APP family members serve both distinct and overlapping functions that need to be considered for therapeutic treatments of Alzheimer’s disease.
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Arnaud K, Oliveira Moreira V, Vincent J, Dallerac G, Dubreuil C, Dupont E, Richter M, Müller UC, Rondi-Reig L, Prochiantz A, Di Nardo AA. Choroid plexus APP regulates adult brain proliferation and animal behavior. Life Sci Alliance 2021; 4:4/11/e202000703. [PMID: 34544751 PMCID: PMC8473726 DOI: 10.26508/lsa.202000703] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 09/08/2021] [Accepted: 09/08/2021] [Indexed: 12/02/2022] Open
Abstract
Adult mouse choroid plexus shows elevated APP expression. sAPPα secreted into the CSF modulates neurogenic niche proliferation, whereas choroid plexus expression of fAD APP mutants leads to reduced niche proliferation, deficits in hippocampus synaptic plasticity, and learning defects. Elevated amyloid precursor protein (APP) expression in the choroid plexus suggests an important role for extracellular APP metabolites such as sAPPα in cerebrospinal fluid. Despite widespread App brain expression, we hypothesized that specifically targeting choroid plexus expression could alter animal physiology. Through various genetic and viral approaches in the adult mouse, we show that choroid plexus APP levels significantly impact proliferation in both subventricular zone and hippocampus dentate gyrus neurogenic niches. Given the role of Aβ peptides in Alzheimer disease pathogenesis, we also tested whether favoring the production of Aβ in choroid plexus could negatively affect niche functions. After AAV5-mediated long-term expression of human mutated APP specifically in the choroid plexus of adult wild-type mice, we observe reduced niche proliferation, reduced hippocampus APP expression, behavioral defects in reversal learning, and deficits in hippocampal long-term potentiation. Our findings highlight the unique role played by the choroid plexus in regulating brain function and suggest that targeting APP in choroid plexus may provide a means to improve hippocampus function and alleviate disease-related burdens.
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Affiliation(s)
- Karen Arnaud
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, Centre National de Recherche Scientifique (CNRS) UMR7241, INSERM U1050, Labex MemoLife, PSL Research University, Paris, France
| | - Vanessa Oliveira Moreira
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, Centre National de Recherche Scientifique (CNRS) UMR7241, INSERM U1050, Labex MemoLife, PSL Research University, Paris, France
| | - Jean Vincent
- Neuroscience Paris Seine, Institut de Biologie Paris Seine (IBPS), Sorbonne Université, CNRS, INSERM, Labex BioPsy, ENP Foundation, Sorbonne University, Paris, France
| | - Glenn Dallerac
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, Centre National de Recherche Scientifique (CNRS) UMR7241, INSERM U1050, Labex MemoLife, PSL Research University, Paris, France
| | - Chantal Dubreuil
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, Centre National de Recherche Scientifique (CNRS) UMR7241, INSERM U1050, Labex MemoLife, PSL Research University, Paris, France
| | - Edmond Dupont
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, Centre National de Recherche Scientifique (CNRS) UMR7241, INSERM U1050, Labex MemoLife, PSL Research University, Paris, France
| | - Max Richter
- Ruprecht-Karls University Heidelberg, Institute of Pharmacy and Molecular Biotechnology, Functional Genomics, Heidelberg, Germany
| | - Ulrike C Müller
- Ruprecht-Karls University Heidelberg, Institute of Pharmacy and Molecular Biotechnology, Functional Genomics, Heidelberg, Germany
| | - Laure Rondi-Reig
- Neuroscience Paris Seine, Institut de Biologie Paris Seine (IBPS), Sorbonne Université, CNRS, INSERM, Labex BioPsy, ENP Foundation, Sorbonne University, Paris, France
| | - Alain Prochiantz
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, Centre National de Recherche Scientifique (CNRS) UMR7241, INSERM U1050, Labex MemoLife, PSL Research University, Paris, France
| | - Ariel A Di Nardo
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, Centre National de Recherche Scientifique (CNRS) UMR7241, INSERM U1050, Labex MemoLife, PSL Research University, Paris, France
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Steubler V, Erdinger S, Back MK, Ludewig S, Fässler D, Richter M, Han K, Slomianka L, Amrein I, von Engelhardt J, Wolfer DP, Korte M, Müller UC. Loss of all three APP family members during development impairs synaptic function and plasticity, disrupts learning, and causes an autism-like phenotype. EMBO J 2021; 40:e107471. [PMID: 34008862 PMCID: PMC8204861 DOI: 10.15252/embj.2020107471] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 03/29/2021] [Accepted: 04/01/2021] [Indexed: 12/15/2022] Open
Abstract
The key role of APP for Alzheimer pathogenesis is well established. However, perinatal lethality of germline knockout mice lacking the entire APP family has so far precluded the analysis of its physiological functions for the developing and adult brain. Here, we generated conditional APP/APLP1/APLP2 triple KO (cTKO) mice lacking the APP family in excitatory forebrain neurons from embryonic day 11.5 onwards. NexCre cTKO mice showed altered brain morphology with agenesis of the corpus callosum and disrupted hippocampal lamination. Further, NexCre cTKOs revealed reduced basal synaptic transmission and drastically reduced long-term potentiation that was associated with reduced dendritic length and reduced spine density of pyramidal cells. With regard to behavior, lack of the APP family leads not only to severe impairments in a panel of tests for learning and memory, but also to an autism-like phenotype including repetitive rearing and climbing, impaired social communication, and deficits in social interaction. Together, our study identifies essential functions of the APP family during development, for normal hippocampal function and circuits important for learning and social behavior.
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Affiliation(s)
- Vicky Steubler
- Department of Functional GenomicsInstitute of Pharmacy and Molecular BiotechnologyHeidelberg UniversityHeidelbergGermany
| | - Susanne Erdinger
- Department of Functional GenomicsInstitute of Pharmacy and Molecular BiotechnologyHeidelberg UniversityHeidelbergGermany
| | - Michaela K Back
- Institute of PathophysiologyFocus Program Translational Neuroscience (FTN)University Medical Center of the Johannes Gutenberg University MainzMainzGermany
| | - Susann Ludewig
- Division of Cellular NeurobiologyZoological Institute, TU BraunschweigBraunschweigGermany
- Helmholtz Centre for Infection Research, Neuroinflammation and Neurodegeneration GroupBraunschweigGermany
| | - Dominique Fässler
- Department of Functional GenomicsInstitute of Pharmacy and Molecular BiotechnologyHeidelberg UniversityHeidelbergGermany
| | - Max Richter
- Department of Functional GenomicsInstitute of Pharmacy and Molecular BiotechnologyHeidelberg UniversityHeidelbergGermany
| | - Kang Han
- Department of Functional GenomicsInstitute of Pharmacy and Molecular BiotechnologyHeidelberg UniversityHeidelbergGermany
| | - Lutz Slomianka
- Institute of Anatomy and Zurich Center for Integrative Human PhysiologyUniversity of ZurichZurichSwitzerland
| | - Irmgard Amrein
- Institute of Anatomy and Zurich Center for Integrative Human PhysiologyUniversity of ZurichZurichSwitzerland
| | - Jakob von Engelhardt
- Institute of PathophysiologyFocus Program Translational Neuroscience (FTN)University Medical Center of the Johannes Gutenberg University MainzMainzGermany
| | - David P Wolfer
- Institute of Anatomy and Zurich Center for Integrative Human PhysiologyUniversity of ZurichZurichSwitzerland
- Institute of Human Movement SciencesETH ZurichZurichSwitzerland
| | - Martin Korte
- Division of Cellular NeurobiologyZoological Institute, TU BraunschweigBraunschweigGermany
- Helmholtz Centre for Infection Research, Neuroinflammation and Neurodegeneration GroupBraunschweigGermany
| | - Ulrike C Müller
- Department of Functional GenomicsInstitute of Pharmacy and Molecular BiotechnologyHeidelberg UniversityHeidelbergGermany
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5
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Mallm JP, Windisch P, Biran A, Gal Z, Schumacher S, Glass R, Herold-Mende C, Meshorer E, Barbus M, Rippe K. Glioblastoma initiating cells are sensitive to histone demethylase inhibition due to epigenetic deregulation. Int J Cancer 2019; 146:1281-1292. [PMID: 31456217 DOI: 10.1002/ijc.32649] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 07/11/2019] [Accepted: 07/30/2019] [Indexed: 12/30/2022]
Abstract
Tumor-initiating cells are a subpopulation of cells that have self-renewal capacity to regenerate a tumor. Here, we identify stem cell-like chromatin features in human glioblastoma initiating cells (GICs) and link them to a loss of the repressive histone H3 lysine 9 trimethylation (H3K9me3) mark. Increasing H3K9me3 levels by histone demethylase inhibition led to cell death in GICs but not in their differentiated counterparts. The induction of apoptosis was accompanied by a loss of the activating H3 lysine 9 acetylation (H3K9ac) modification and accumulation of DNA damage and downregulation of DNA damage response genes. Upon knockdown of histone demethylases, KDM4C and KDM7A both differentiation and DNA damage were induced. Thus, the H3K9me3-H3K9ac equilibrium is crucial for GIC viability and represents a chromatin feature that can be exploited to specifically target this tumor subpopulation.
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Affiliation(s)
- Jan-Philipp Mallm
- Division of Chromatin Networks, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Paul Windisch
- Division of Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Alva Biran
- Department of Genetics, Institute of Life Sciences, and the Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Zoltan Gal
- Division of Neurosurgical Research, Department of Neurosurgery, University of Heidelberg, Heidelberg, Germany
| | - Sabrina Schumacher
- Division of Chromatin Networks, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Rainer Glass
- Neurosurgical Research, University Hospital, LMU Munich, Munich, Germany
| | - Christel Herold-Mende
- Division of Neurosurgical Research, Department of Neurosurgery, University of Heidelberg, Heidelberg, Germany
| | - Eran Meshorer
- Department of Genetics, Institute of Life Sciences, and the Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Martje Barbus
- Division of Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Karsten Rippe
- Division of Chromatin Networks, German Cancer Research Center (DKFZ), Heidelberg, Germany
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6
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Presenilin-mediated cleavage of APP regulates synaptotagmin-7 and presynaptic plasticity. Nat Commun 2018; 9:4780. [PMID: 30429473 PMCID: PMC6235831 DOI: 10.1038/s41467-018-06813-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 09/19/2018] [Indexed: 11/09/2022] Open
Abstract
Mutations of the intramembrane protease presenilin (PS) or of its main substrate, the amyloid precursor protein (APP), cause early-onset form of Alzheimer disease. PS and APP interact with proteins of the neurotransmitter release machinery without identified functional consequences. Here we report that genetic deletion of PS markedly decreases the presynaptic levels of the Ca2+ sensor synaptotagmin-7 (Syt7) leading to impaired synaptic facilitation and replenishment of synaptic vesicles. The regulation of Syt7 expression by PS occurs post-transcriptionally and depends on γ-secretase proteolytic activity. It requires the substrate APP as revealed by the combined genetic invalidation of APP and PS1, and in particular the APP-Cterminal fragments which interact with Syt7 and accumulate in synaptic terminals under pharmacological or genetic inhibition of γ-secretase. Thus, we uncover a role of PS in presynaptic mechanisms, through APP cleavage and regulation of Syt7, that highlights aberrant synaptic vesicle processing as a possible new pathway in AD. Mutations in presenilin, which cleaves amyloid precursor protein, cause familial Alzheimer’s Disease. Here, the authors show that loss of presenilin leads to loss of synaptotagmin 7, leading to impaired presynaptic release.
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7
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Dugger BN, Perl DP, Carlson GA. Neurodegenerative Disease Transmission and Transgenesis in Mice. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a023549. [PMID: 28193724 DOI: 10.1101/cshperspect.a023549] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Although the discovery of the prion protein (PrP) resulted from its co-purification with scrapie infectivity in Syrian hamsters, work with genetically defined and genetically modified mice proved crucial for understanding the fundamental processes involved not only in prion diseases caused by PrP misfolding, aggregation, and spread but also in other, much more common, neurodegenerative brain diseases. In this review, we focus on methodological and conceptual approaches used to study scrapie and related PrP misfolding diseases in mice and how these approaches have advanced our understanding of related disorders including Alzheimer's and Parkinson's disease.
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Affiliation(s)
- Brittany N Dugger
- Institute for Neurodegenerative Diseases, Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California 94158
| | - Daniel P Perl
- F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
| | - George A Carlson
- Institute for Neurodegenerative Diseases, Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California 94158.,McLaughlin Research Institute of Biomedical Sciences, Great Falls, Montana 59405
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8
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Callahan DG, Taylor WM, Tilearcio M, Cavanaugh T, Selkoe DJ, Young-Pearse TL. Embryonic mosaic deletion of APP results in displaced Reelin-expressing cells in the cerebral cortex. Dev Biol 2017; 424:138-146. [PMID: 28284905 DOI: 10.1016/j.ydbio.2017.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 03/03/2017] [Accepted: 03/07/2017] [Indexed: 02/06/2023]
Abstract
It is widely accepted that amyloid precursor protein (APP) plays a central role in the pathogenesis of Alzheimer's disease. In addition, APP has been proposed to have functions in numerous biological processes including neuronal proliferation, differentiation, migration, axon guidance, and neurite outgrowth, as well as in synapse formation and function. However, germline knockout of APP yields relatively subtle phenotypes, and brain development appears grossly normal. This is thought to be due in part to functional compensation by APP family members and other type I transmembrane proteins. Here, we have generated a conditional mouse knockout for APP that is controlled temporally using CreER and tamoxifen administration. We show that total cortical expression of APP is reduced following tamoxifen administration during embryonic time points critical for cortical lamination, and that this results in displacement of Reelin-positive cells below the cortical plate with a concurrent elevation in Reelin protein levels. These results support a role for APP in cortical lamination and demonstrate the utility of a conditional knockout approach in which APP can be deleted with temporal control in vivo. This new tool should be useful for many different applications in the study of APP function across the mammalian life span.
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Affiliation(s)
- D G Callahan
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - W M Taylor
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - M Tilearcio
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - T Cavanaugh
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - D J Selkoe
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - T L Young-Pearse
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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Heterochromatin Protein 1β (HP1β) has distinct functions and distinct nuclear distribution in pluripotent versus differentiated cells. Genome Biol 2015; 16:213. [PMID: 26415775 PMCID: PMC4587738 DOI: 10.1186/s13059-015-0760-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Accepted: 08/25/2015] [Indexed: 11/22/2022] Open
Abstract
Background Pluripotent embryonic stem cells (ESCs) have the unique ability to differentiate into every cell type and to self-renew. These characteristics correlate with a distinct nuclear architecture, epigenetic signatures enriched for active chromatin marks and hyperdynamic binding of structural chromatin proteins. Recently, several chromatin-related proteins have been shown to regulate ESC pluripotency and/or differentiation, yet the role of the major heterochromatin proteins in pluripotency is unknown. Results Here we identify Heterochromatin Protein 1β (HP1β) as an essential protein for proper differentiation, and, unexpectedly, for the maintenance of pluripotency in ESCs. In pluripotent and differentiated cells HP1β is differentially localized and differentially associated with chromatin. Deletion of HP1β, but not HP1α, in ESCs provokes a loss of the morphological and proliferative characteristics of embryonic pluripotent cells, reduces expression of pluripotency factors and causes aberrant differentiation. However, in differentiated cells, loss of HP1β has the opposite effect, perturbing maintenance of the differentiation state and facilitating reprogramming to an induced pluripotent state. Microscopy, biochemical fractionation and chromatin immunoprecipitation reveal a diffuse nucleoplasmic distribution, weak association with chromatin and high expression levels for HP1β in ESCs. The minor fraction of HP1β that is chromatin-bound in ESCs is enriched within exons, unlike the situation in differentiated cells, where it binds heterochromatic satellite repeats and chromocenters. Conclusions We demonstrate an unexpected duality in the role of HP1β: it is essential in ESCs for maintaining pluripotency, while it is required for proper differentiation in differentiated cells. Thus, HP1β function both depends on, and regulates, the pluripotent state. Electronic supplementary material The online version of this article (doi:10.1186/s13059-015-0760-8) contains supplementary material, which is available to authorized users.
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10
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Weyer SW, Zagrebelsky M, Herrmann U, Hick M, Ganss L, Gobbert J, Gruber M, Altmann C, Korte M, Deller T, Müller UC. Comparative analysis of single and combined APP/APLP knockouts reveals reduced spine density in APP-KO mice that is prevented by APPsα expression. Acta Neuropathol Commun 2014; 2:36. [PMID: 24684730 PMCID: PMC4023627 DOI: 10.1186/2051-5960-2-36] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 03/07/2014] [Indexed: 11/21/2022] Open
Abstract
Synaptic dysfunction and synapse loss are key features of Alzheimer's pathogenesis. Previously, we showed an essential function of APP and APLP2 for synaptic plasticity, learning and memory. Here, we used organotypic hippocampal cultures to investigate the specific role(s) of APP family members and their fragments for dendritic complexity and spine formation of principal neurons within the hippocampus. Whereas CA1 neurons from APLP1-KO or APLP2-KO mice showed normal neuronal morphology and spine density, APP-KO mice revealed a highly reduced dendritic complexity in mid-apical dendrites. Despite unaltered morphology of APLP2-KO neurons, combined APP/APLP2-DKO mutants showed an additional branching defect in proximal apical dendrites, indicating redundancy and a combined function of APP and APLP2 for dendritic architecture. Remarkably, APP-KO neurons showed a pronounced decrease in spine density and reductions in the number of mushroom spines. No further decrease in spine density, however, was detectable in APP/APLP2-DKO mice. Mechanistically, using APPsα-KI mice lacking transmembrane APP and expressing solely the secreted APPsα fragment we demonstrate that APPsα expression alone is sufficient to prevent the defects in spine density observed in APP-KO mice. Collectively, these studies reveal a combined role of APP and APLP2 for dendritic architecture and a unique function of secreted APPs for spine density.
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Affiliation(s)
- Sascha W Weyer
- Department of Bioinformatics and Functional Genomics, Ruprecht-Karls University Heidelberg, Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 364, Heidelberg D-69120, Germany
| | - Marta Zagrebelsky
- TU Braunschweig, Zoological Institute, Cellular Neurobiology, Spielmannstr. 7, Braunschweig D-38106, Germany
| | - Ulrike Herrmann
- TU Braunschweig, Zoological Institute, Cellular Neurobiology, Spielmannstr. 7, Braunschweig D-38106, Germany
| | - Meike Hick
- Department of Bioinformatics and Functional Genomics, Ruprecht-Karls University Heidelberg, Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 364, Heidelberg D-69120, Germany
| | - Lennard Ganss
- Department of Bioinformatics and Functional Genomics, Ruprecht-Karls University Heidelberg, Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 364, Heidelberg D-69120, Germany
- Present address: Department of Applied Tumor Biology, Ruprecht-Karls University Heidelberg, Institute of Pathology, University of Heidelberg, Heidelberg D-69120, Germany
| | - Julia Gobbert
- Department of Bioinformatics and Functional Genomics, Ruprecht-Karls University Heidelberg, Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 364, Heidelberg D-69120, Germany
| | - Morna Gruber
- Goethe University Frankfurt, Institute of Clinical Neuroanatomy, Neuroscience Center, Theodor-Stern-Kai 7, Frankfurt am Main D-60596, Germany
| | - Christine Altmann
- Goethe University Frankfurt, Institute of Clinical Neuroanatomy, Neuroscience Center, Theodor-Stern-Kai 7, Frankfurt am Main D-60596, Germany
| | - Martin Korte
- TU Braunschweig, Zoological Institute, Cellular Neurobiology, Spielmannstr. 7, Braunschweig D-38106, Germany
| | - Thomas Deller
- Goethe University Frankfurt, Institute of Clinical Neuroanatomy, Neuroscience Center, Theodor-Stern-Kai 7, Frankfurt am Main D-60596, Germany
| | - Ulrike C Müller
- Department of Bioinformatics and Functional Genomics, Ruprecht-Karls University Heidelberg, Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 364, Heidelberg D-69120, Germany
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Abstract
Biochemical and genetic evidence establishes a central role of the amyloid precursor protein (APP) in Alzheimer disease (AD) pathogenesis. Biochemically, deposition of the β-amyloid (Aβ) peptides produced from proteolytic processing of APP forms the defining pathological hallmark of AD; genetically, both point mutations and duplications of wild-type APP are linked to a subset of early onset of familial AD (FAD) and cerebral amyloid angiopathy. As such, the biological functions of APP and its processing products have been the subject of intense investigation, and the past 20+ years of research have met with both excitement and challenges. This article will review the current understanding of the physiological functions of APP in the context of APP family members.
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Affiliation(s)
- Ulrike C Müller
- Institute for Pharmacy and Molecular Biotechnology, University of Heidelberg, D-69120 Heidelberg, Germany.
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Dysregulation of hypoxia-inducible factor by presenilin/γ-secretase loss-of-function mutations. J Neurosci 2013; 33:1915-26. [PMID: 23365231 DOI: 10.1523/jneurosci.3402-12.2013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Presenilin (PSEN) 1 and 2 are the catalytic components of the γ-secretase complex, which cleaves a variety of proteins, including the amyloid precursor protein (APP). Proteolysis of APP leads to the formation of the APP intracellular domain (AICD) and amyloid β that is crucially involved in the pathogenesis of Alzheimer's disease. Prolyl-4-hydroxylase-domain (PHD) proteins regulate the hypoxia-inducible factors (HIFs), the master regulators of the hypoxic response. We previously identified the FK506 binding protein 38 (FKBP38) as a negative regulator of PHD2. Genetic ablation of PSEN1/2 has been shown to increase FKBP38 protein levels. Therefore, we investigated the role of PSEN1/2 in the oxygen sensing pathway using a variety of genetically modified cell and mouse lines. Increased FKBP38 protein levels and decreased PHD2 protein levels were found in PSEN1/2-deficient mouse embryonic fibroblasts and in the cortex of forebrain-specific PSEN1/2 conditional double knock-out mice. Hypoxic HIF-1α protein accumulation and transcriptional activity were decreased, despite reduced PHD2 protein levels. Proteolytic γ-secretase function of PSEN1/2 was needed for proper HIF activation. Intriguingly, PSEN1/2 mutations identified in Alzheimer patients differentially affected the hypoxic response, involving the generation of AICD. Together, our results suggest a direct role for PSEN in the regulation of the oxygen sensing pathway via the APP/AICD cleavage cascade.
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Teif VB, Vainshtein Y, Caudron-Herger M, Mallm JP, Marth C, Höfer T, Rippe K. Genome-wide nucleosome positioning during embryonic stem cell development. Nat Struct Mol Biol 2012; 19:1185-92. [PMID: 23085715 DOI: 10.1038/nsmb.2419] [Citation(s) in RCA: 187] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 09/19/2012] [Indexed: 01/13/2023]
Abstract
We determined genome-wide nucleosome occupancies in mouse embryonic stem cells and their neural progenitor and embryonic fibroblast counterparts to assess features associated with nucleosome positioning during lineage commitment. Cell-type- and protein-specific binding preferences of transcription factors to sites with either low (Myc, Klf4 and Zfx) or high (Nanog, Oct4 and Sox2) nucleosome occupancy as well as complex patterns for CTCF were identified. Nucleosome-depleted regions around transcription start and transcription termination sites were broad and more pronounced for active genes, with distinct patterns for promoters classified according to CpG content or histone methylation marks. Throughout the genome, nucleosome occupancy was correlated with certain histone methylation or acetylation modifications. In addition, the average nucleosome repeat length increased during differentiation by 5-7 base pairs, with local variations for specific regions. Our results reveal regulatory mechanisms of cell differentiation that involve nucleosome repositioning.
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Affiliation(s)
- Vladimir B Teif
- Research Group Genome Organization and Function, Deutsches Krebsforschungszentrum, Heidelberg, Germany.
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14
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Lazarov O, Demars MP. All in the Family: How the APPs Regulate Neurogenesis. Front Neurosci 2012; 6:81. [PMID: 22675290 PMCID: PMC3366480 DOI: 10.3389/fnins.2012.00081] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 05/14/2012] [Indexed: 12/23/2022] Open
Abstract
Recent intriguing evidence suggests that metabolites of amyloid precursor protein (APP), mutated in familial forms of Alzheimer’s disease (AD), play critical roles in developmental and postnatal neurogenesis. Of note is soluble APPα (sAPPα) that regulates neural progenitor cell proliferation. The APP family encompasses a group of ubiquitously expressed and evolutionarily conserved, type I transmembrane glycoproteins, whose functions have yet to be fully elucidated. APP can undergo proteolytic cleavage by mutually exclusive pathways. The subtle structural differences between metabolites generated in the different pathways, as well as their equilibrium, may be crucial for neuronal function. The implications of this new body of evidence are significant. Miscleavage of APP would readily impact developmental and postnatal neurogenesis, which might contribute to cognitive deficits characterizing Alzheimer’s disease. This review will discuss the implications of the role of the APP family in neurogenesis for neuronal development, cognitive function, and brain disorders that compromise learning and memory, such as AD.
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Affiliation(s)
- Orly Lazarov
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago Chicago, IL, USA
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15
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Functional consequences of the lack of amyloid precursor protein in the mouse dentate gyrus in vivo. Exp Brain Res 2011; 217:441-7. [PMID: 22076403 DOI: 10.1007/s00221-011-2911-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 10/07/2011] [Indexed: 01/15/2023]
Abstract
The amyloid precursor protein (APP) plays a crucial role in the pathogenesis of Alzheimer's disease. Here, we studied whether the lack of APP affects the synaptic properties in the dentate gyrus by measuring granule cell field potentials evoked by perforant path stimulation in anesthetized 9-11-month-old APP-deficient mice in vivo. We found decreased paired-pulse facilitation, indicating altered presynaptic short-term plasticity in the APP-deficient dentate gyrus. In contrast, excitatory synaptic strength and granule cell firing were unchanged in APP knockout mice. Likewise, long-term potentiation (LTP) induced by a theta-burst stimulation protocol was not impaired in the absence of APP. These findings suggest that the deletion of APP may affect presynaptic plasticity of synaptic transmission at the perforant path-granule cell synapse but leaves synaptic efficacy intact and LTP preserved, possibly due to functional redundancy within the APP gene family.
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Aydin D, Weyer SW, Müller UC. Functions of the APP gene family in the nervous system: insights from mouse models. Exp Brain Res 2011; 217:423-34. [PMID: 21931985 DOI: 10.1007/s00221-011-2861-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 08/30/2011] [Indexed: 09/02/2023]
Abstract
The amyloid precursor protein (APP) plays a key role in the pathogenesis of Alzheimer's disease (AD), as proteolytical cleavage of APP gives rise to the β-amyloid peptide which is deposited in the brains of Alzheimer patients. During the past years, intense research efforts have been directed at elucidating the physiological function(s) of APP and the question of whether a perturbation of these functions contributes to AD pathogenesis. Indeed, a growing body of evidence has accumulated supporting a role of APP and the two closely related homologues APLP1 and APLP2 in various aspects of nervous system development and function, in particular, for synapse formation and function. This review summarizes recent insights into the in vivo role of the APP gene family from mice lacking individual or combinations of APP family members, with particular emphasis on recently generated knockin mice to examine the in vivo relevance of distinct functional domains.
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Affiliation(s)
- Dorothee Aydin
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
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Abstract
The amyloid precursor protein (APP) has been under intensive study in recent years, mainly due to its critical role in the pathogenesis of Alzheimer's disease (AD). β-Amyloid (Aβ) peptides generated from APP proteolytic cleavage can aggregate, leading to plaque formation in human AD brains. Point mutations of APP affecting Aβ production are found to be causal for hereditary early onset familial AD. It is very likely that elucidating the physiological properties of APP will greatly facilitate the understanding of its role in AD pathogenesis. A number of APP loss- and gain-of-function models have been established in model organisms including Caenorhabditis elegans, Drosophila, zebrafish and mouse. These in vivo models provide us valuable insights into APP physiological functions. In addition, several knock-in mouse models expressing mutant APP at a physiological level are available to allow us to study AD pathogenesis without APP overexpression. This article will review the current physiological and pathophysiological animal models of APP.
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Aydin D, Filippov MA, Tschäpe JA, Gretz N, Prinz M, Eils R, Brors B, Müller UC. Comparative transcriptome profiling of amyloid precursor protein family members in the adult cortex. BMC Genomics 2011; 12:160. [PMID: 21435241 PMCID: PMC3080314 DOI: 10.1186/1471-2164-12-160] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 03/24/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The β-amyloid precursor protein (APP) and the related β-amyloid precursor-like proteins (APLPs) undergo complex proteolytic processing giving rise to several fragments. Whereas it is well established that Aβ accumulation is a central trigger for Alzheimer's disease, the physiological role of APP family members and their diverse proteolytic products is still largely unknown. The secreted APPsα ectodomain has been shown to be involved in neuroprotection and synaptic plasticity. The γ-secretase-generated APP intracellular domain (AICD) functions as a transcriptional regulator in heterologous reporter assays although its role for endogenous gene regulation has remained controversial. RESULTS To gain further insight into the molecular changes associated with knockout phenotypes and to elucidate the physiological functions of APP family members including their proposed role as transcriptional regulators, we performed DNA microarray transcriptome profiling of prefrontal cortex of adult wild-type (WT), APP knockout (APP-/-), APLP2 knockout (APLP2-/-) and APPsα knockin mice (APPα/α) expressing solely the secreted APPsα ectodomain. Biological pathways affected by the lack of APP family members included neurogenesis, transcription, and kinase activity. Comparative analysis of transcriptome changes between mutant and wild-type mice, followed by qPCR validation, identified co-regulated gene sets. Interestingly, these included heat shock proteins and plasticity-related genes that were both down-regulated in knockout cortices. In contrast, we failed to detect significant differences in expression of previously proposed AICD target genes including Bace1, Kai1, Gsk3b, p53, Tip60, and Vglut2. Only Egfr was slightly up-regulated in APLP2-/- mice. Comparison of APP-/- and APPα/α with wild-type mice revealed a high proportion of co-regulated genes indicating an important role of the C-terminus for cellular signaling. Finally, comparison of APLP2-/- on different genetic backgrounds revealed that background-related transcriptome changes may dominate over changes due to the knockout of a single gene. CONCLUSION Shared transcriptome profiles corroborated closely related physiological functions of APP family members in the adult central nervous system. As expression of proposed AICD target genes was not altered in adult cortex, this may indicate that these genes are not affected by lack of APP under resting conditions or only in a small subset of cells.
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Affiliation(s)
- Dorothee Aydin
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, D-69120 Heidelberg, Germany
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