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Niere F, Uneri A, McArdle CJ, Deng Z, Egido-Betancourt HX, Cacheaux LP, Namjoshi SV, Taylor WC, Wang X, Barth SH, Reynoldson C, Penaranda J, Stierer MP, Heaney CF, Craft S, Keene CD, Ma T, Raab-Graham KF. Aberrant DJ-1 expression underlies L-type calcium channel hypoactivity in dendrites in tuberous sclerosis complex and Alzheimer's disease. Proc Natl Acad Sci U S A 2023; 120:e2301534120. [PMID: 37903257 PMCID: PMC10636362 DOI: 10.1073/pnas.2301534120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 09/25/2023] [Indexed: 11/01/2023] Open
Abstract
L-type voltage-gated calcium (Ca2+) channels (L-VGCC) dysfunction is implicated in several neurological and psychiatric diseases. While a popular therapeutic target, it is unknown whether molecular mechanisms leading to disrupted L-VGCC across neurodegenerative disorders are conserved. Importantly, L-VGCC integrate synaptic signals to facilitate a plethora of cellular mechanisms; however, mechanisms that regulate L-VGCC channel density and subcellular compartmentalization are understudied. Herein, we report that in disease models with overactive mammalian target of rapamycin complex 1 (mTORC1) signaling (or mTORopathies), deficits in dendritic L-VGCC activity are associated with increased expression of the RNA-binding protein (RBP) Parkinsonism-associated deglycase (DJ-1). DJ-1 binds the mRNA coding for the alpha and auxiliary Ca2+ channel subunits CaV1.2 and α2δ2, and represses their mRNA translation, only in the disease states, specifically preclinical models of tuberous sclerosis complex (TSC) and Alzheimer's disease (AD). In agreement, DJ-1-mediated repression of CaV1.2/α2δ2 protein synthesis in dendrites is exaggerated in mouse models of AD and TSC, resulting in deficits in dendritic L-VGCC calcium activity. Finding of DJ-1-regulated L-VGCC activity in dendrites in TSC and AD provides a unique signaling pathway that can be targeted in clinical mTORopathies.
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Affiliation(s)
- Farr Niere
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
- Department of Biology, North Carolina Agricultural and Technical State University, Greensboro, NC27411
| | - Ayse Uneri
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Colin J. McArdle
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Zhiyong Deng
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Hailey X. Egido-Betancourt
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Luisa P. Cacheaux
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Sanjeev V. Namjoshi
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - William C. Taylor
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Xin Wang
- Department of Internal Medicine, Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Samuel H. Barth
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Cameron Reynoldson
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Juan Penaranda
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Michael P. Stierer
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Chelcie F. Heaney
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Suzanne Craft
- Department of Internal Medicine, Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC27157
- Wake Forest Alzheimer’s Disease Research Center, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - C. Dirk Keene
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA98104
| | - Tao Ma
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
- Department of Internal Medicine, Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Kimberly F. Raab-Graham
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
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Ganbat D, Jeon JK, Lee Y, Kim SS. Exploring the Pathological Effect of Aβ42 Oligomers on Neural Networks in Primary Cortical Neuron Culture. Int J Mol Sci 2023; 24:ijms24076641. [PMID: 37047612 PMCID: PMC10094920 DOI: 10.3390/ijms24076641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 03/29/2023] [Accepted: 03/30/2023] [Indexed: 04/05/2023] Open
Abstract
Alzheimer’s disease (AD) is a multifactorial disorder that affects cognitive functioning, behavior, and neuronal properties. The neuronal dysfunction is primarily responsible for cognitive decline in AD patients, with many causal factors including plaque accumulation of Aβ42. Neural hyperactivity induced by Aβ42 deposition causes abnormalities in neural networks, leading to alterations in synaptic activity and interneuron dysfunction. Even though neuroimaging techniques elucidated the underlying mechanism of neural connectivity, precise understanding at the cellular level is still elusive. Previous multielectrode array studies have examined the neuronal network modulation in in vitro cultures revealing the relevance of ion channels and the chemical modulators in the presence of Aβ42. In this study, we investigated neuronal connectivity and dynamic changes using a high-density multielectrode array, particularly looking at network-wide parameter changes over time. By comparing the neuronal network between normal and Aβ42treated neuronal cultures, it was possible to discover the direct pathological effect of the Aβ42 oligomer altering the network characteristics. The detrimental effects of the Aβ42 oligomer included not only a decline in spike activation but also a qualitative impairment in neural connectivity as well as a disorientation of dispersibility. As a result, this will improve our understanding of how neural networks are modified during AD progression.
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Affiliation(s)
- Dulguun Ganbat
- Department of Pharmacy, Hanyang University, Ansan 15588, Republic of Korea
| | - Jae Kyong Jeon
- Department of Pharmacy, Hanyang University, Ansan 15588, Republic of Korea
| | - Yunjong Lee
- Department of Pharmacology, School of Medicine, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Sang Seong Kim
- Department of Pharmacy, Hanyang University, Ansan 15588, Republic of Korea
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3
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Baltissen D, Bold CS, Rehra L, Banićević M, Fricke J, Just J, Ludewig S, Buchholz CJ, Korte M, Müller UC. APPsα rescues CDK5 and GSK3β dysregulation and restores normal spine density in Tau transgenic mice. Front Cell Neurosci 2023; 17:1106176. [PMID: 36779015 PMCID: PMC9909437 DOI: 10.3389/fncel.2023.1106176] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 01/02/2023] [Indexed: 01/27/2023] Open
Abstract
The Tau protein can be phosphorylated by numerous kinases. In Alzheimer's disease (AD) hyperphosphorylated Tau species accumulate as neurofibrillary tangles that constitute a major hallmark of AD. AD is further characterized by extracellular Aβ plaques, derived from the β-amyloid precursor protein APP. Whereas Aβ is produced by amyloidogenic APP processing, APP processing along the competing non-amyloidogenic pathway results in the secretion of neurotrophic and synaptotrophic APPsα. Recently, we demonstrated that APPsα has therapeutic effects in transgenic AD model mice and rescues Aβ-dependent impairments. Here, we examined the potential of APPsα to regulate two major Tau kinases, GSK3β and CDK5 in THY-Tau22 mice, a widely used mouse model of tauopathy. Immunohistochemistry revealed a dramatic increase in pathologically phosphorylated (AT8 and AT180) or misfolded Tau species (MC1) in the hippocampus of THY-Tau22 mice between 3 and 12 months of age. Using a highly sensitive radioactive kinase assay with recombinant human Tau as a substrate and immunoblotting, we demonstrate an increase in GSK3β and CDK5 activity in the hippocampus of THY-Tau22 mice. Interestingly, AAV-mediated intracranial expression of APPsα in THY-Tau22 mice efficiently restored normal GSK3β and CDK5 activity. Western blot analysis revealed upregulation of the CDK5 regulatory proteins p35 and p25, indicating CDK5 hyperactivation in THY-Tau22 mice. Strikingly, AAV-APPsα rescued p25 upregulation to wild-type levels even at stages of advanced Tau pathology. Sarkosyl fractionation used to study the abundance of soluble and insoluble phospho-Tau species revealed increased soluble AT8-Tau and decreased insoluble AT100-Tau species upon AAV-APPsα injection. Moreover, AAV-APPsα reduced misfolded (MC1) Tau species, particularly in somatodendritic compartments of CA1 pyramidal neurons. Finally, we show that AAV-APPsα upregulated PSD95 expression and rescued deficits in spine density of THY-Tau22 mice. Together our findings suggest that APPsα holds therapeutic potential to mitigate Tau-induced pathology.
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Affiliation(s)
- Danny Baltissen
- Department of Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Charlotte S. Bold
- Department of Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Lena Rehra
- Department of Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Marija Banićević
- Department of Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Justus Fricke
- Department of Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Jennifer Just
- Department of Cellular Neurobiology, Zoological Institute, Technical University of Braunschweig, Braunschweig, Germany
| | - Susann Ludewig
- Department of Cellular Neurobiology, Zoological Institute, Technical University of Braunschweig, Braunschweig, Germany
| | - Christian J. Buchholz
- Department of Molecular Biotechnology and Gene Therapy, Paul-Ehrlich-Institut, Langen, Germany
| | - Martin Korte
- Department of Cellular Neurobiology, Zoological Institute, Technical University of Braunschweig, Braunschweig, Germany,Helmholtz Centre for Infection Research, Neuroinflammation and Neurodegeneration Group, Braunschweig, Germany
| | - Ulrike C. Müller
- Department of Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany,*Correspondence: Ulrike C. Müller,
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Paschou M, Liaropoulou D, Kalaitzaki V, Efthimiopoulos S, Papazafiri P. Knockdown of Amyloid Precursor Protein Increases Ion Channel Expression and Alters Ca 2+ Signaling Pathways. Int J Mol Sci 2023; 24:ijms24032302. [PMID: 36768625 PMCID: PMC9917207 DOI: 10.3390/ijms24032302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 01/27/2023] Open
Abstract
Although the physiological role of the full-length Amyloid Precursor Protein (APP) and its proteolytic fragments remains unclear, they are definitively crucial for normal synaptic function. Herein, we report that the downregulation of APP in SH-SY5Y cells, using short hairpin RNA (shRNA), alters the expression pattern of several ion channels and signaling proteins that are involved in synaptic and Ca2+ signaling. Specifically, the levels of GluR2 and GluR4 subunits of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid glutamate receptors (AMPAR) were significantly increased with APP knockdown. Similarly, the expression of the majority of endoplasmic reticulum (ER) residing proteins, such as the ER Ca2+ channels IP3R (Inositol 1,4,5-triphosphate Receptor) and RyR (Ryanodine Receptor), the Ca2+ pump SERCA2 (Sarco/endoplasmic reticulum Ca2+ ATPase 2) and the ER Ca2+ sensor STIM1 (Stromal Interaction Molecule 1) was upregulated. A shift towards the upregulation of p-AKT, p-PP2A, and p-CaMKIV and the downregulation of p-GSK, p-ERK1/2, p-CaMKII, and p-CREB was observed, interconnecting Ca2+ signal transduction from the plasma membrane and ER to the nucleus. Interestingly, we detected reduced responses to several physiological stimuli, with the most prominent being the ineffectiveness of SH-SY5Y/APP- cells to mobilize Ca2+ from the ER upon carbachol-induced Ca2+ release through IP3Rs and RyRs. Our data further support an emerging yet perplexing role of APP within a functional molecular network of membrane and cytoplasmic proteins implicated in Ca2+ signaling.
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Affiliation(s)
- Maria Paschou
- Division of Animal and Human Physiology, Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece
| | - Danai Liaropoulou
- Division of Animal and Human Physiology, Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece
| | - Vasileia Kalaitzaki
- Division of Animal and Human Physiology, Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece
- Institute of Laboratory Animal Science, University of Zurich, 8952 Schlieren, Switzerland
| | - Spiros Efthimiopoulos
- Division of Animal and Human Physiology, Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece
- Correspondence: (S.E.); (P.P.)
| | - Panagiota Papazafiri
- Division of Animal and Human Physiology, Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece
- Correspondence: (S.E.); (P.P.)
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5
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Li Y, Wang JZ, Deng YM, Wang K, Yang L, Long C. Amyloid-β Protein Precursor Regulates Electrophysiological Properties in the Hippocampus via Altered Kv1.4 Expression and Function in Mice. J Alzheimers Dis 2023; 92:1241-1256. [PMID: 36872774 DOI: 10.3233/jad-220606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
BACKGROUND Amyloid-β protein precursor (AβPP) is enriched in neurons. However, the mechanism underlying AβPP regulation of neuronal activity is poorly understood. Potassium channels are critically involved in neuronal excitability. In hippocampus, A-type potassium channels are highly expressed and involved in determining neuronal spiking. OBJECTIVE We explored hippocampal local field potential (LFP) and spiking in the presence and absence of AβPP, and the potential involvement of an A-type potassium channel. METHODS We used in vivo extracellular recording and whole-cell patch-clamp recording to determine neuronal activity, current density of A-type potassium currents, and western blot to detect changes in related protein levels. RESULTS Abnormal LFP was observed in AβPP-/- mice, including reduced beta and gamma power, and increased epsilon and ripple power. The firing rate of glutamatergic neurons reduced significantly, in line with an increased action potential rheobase. Given that A-type potassium channels regulate neuronal firing, we measured the protein levels and function of two major A-type potassium channels and found that the post-transcriptional level of Kv1.4, but not Kv4.2, was significantly increased in the AβPP-/- mice. This resulted in a marked increase in the peak time of A-type transient outward potassium currents in both glutamatergic and gamma-aminobutyric acid-ergic (GABAergic) neurons. Furthermore, a mechanistic experiment using human embryonic kidney 293 (HEK293) cells revealed that the AβPP deficiency-induced increase in Kv1.4 may not involve protein-protein interaction between AβPP and Kv1.4. CONCLUSION This study suggests that AβPP modulates neuronal firing and oscillatory activity in the hippocampus, and Kv1.4 may be involved in mediating the modulation.
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Affiliation(s)
- Yi Li
- South China Normal University-Panyu Central Hospital Joint Laboratory of Translational Medical Research, Panyu Central Hospital, Guangzhou, China
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Jin-Zhao Wang
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Yue-Ming Deng
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Kun Wang
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Li Yang
- School of Life Sciences, Guangzhou University, Guangzhou, China
| | - Cheng Long
- South China Normal University-Panyu Central Hospital Joint Laboratory of Translational Medical Research, Panyu Central Hospital, Guangzhou, China
- School of Life Sciences, South China Normal University, Guangzhou, China
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6
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Arjun McKinney A, Petrova R, Panagiotakos G. Calcium and activity-dependent signaling in the developing cerebral cortex. Development 2022; 149:276624. [PMID: 36102617 PMCID: PMC9578689 DOI: 10.1242/dev.198853] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Calcium influx can be stimulated by various intra- and extracellular signals to set coordinated gene expression programs into motion. As such, the precise regulation of intracellular calcium represents a nexus between environmental cues and intrinsic genetic programs. Mounting genetic evidence points to a role for the deregulation of intracellular calcium signaling in neuropsychiatric disorders of developmental origin. These findings have prompted renewed enthusiasm for understanding the roles of calcium during normal and dysfunctional prenatal development. In this Review, we describe the fundamental mechanisms through which calcium is spatiotemporally regulated and directs early neurodevelopmental events. We also discuss unanswered questions about intracellular calcium regulation during the emergence of neurodevelopmental disease, and provide evidence that disruption of cell-specific calcium homeostasis and/or redeployment of developmental calcium signaling mechanisms may contribute to adult neurological disorders. We propose that understanding the normal developmental events that build the nervous system will rely on gaining insights into cell type-specific calcium signaling mechanisms. Such an understanding will enable therapeutic strategies targeting calcium-dependent mechanisms to mitigate disease.
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Affiliation(s)
- Arpana Arjun McKinney
- University of California 1 Graduate Program in Developmental and Stem Cell Biology , , San Francisco, CA 94143 , USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California 2 , San Francisco, CA 94143 , USA
- University of California 3 Department of Biochemistry and Biophysics , , San Francisco, CA 94143 , USA
- Kavli Institute for Fundamental Neuroscience, University of California 4 , San Francisco, CA 94143 , USA
| | - Ralitsa Petrova
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California 2 , San Francisco, CA 94143 , USA
- University of California 3 Department of Biochemistry and Biophysics , , San Francisco, CA 94143 , USA
- Kavli Institute for Fundamental Neuroscience, University of California 4 , San Francisco, CA 94143 , USA
| | - Georgia Panagiotakos
- University of California 1 Graduate Program in Developmental and Stem Cell Biology , , San Francisco, CA 94143 , USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California 2 , San Francisco, CA 94143 , USA
- University of California 3 Department of Biochemistry and Biophysics , , San Francisco, CA 94143 , USA
- Kavli Institute for Fundamental Neuroscience, University of California 4 , San Francisco, CA 94143 , USA
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7
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Bold CS, Baltissen D, Ludewig S, Back MK, Just J, Kilian L, Erdinger S, Banicevic M, Rehra L, Almouhanna F, Nigri M, Wolfer DP, Spilger R, Rohr K, Kann O, Buchholz CJ, von Engelhardt J, Korte M, Müller UC. APPsα Rescues Tau-Induced Synaptic Pathology. J Neurosci 2022; 42:5782-5802. [PMID: 35667850 PMCID: PMC9302470 DOI: 10.1523/jneurosci.2200-21.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 04/06/2022] [Accepted: 05/22/2022] [Indexed: 01/22/2023] Open
Abstract
Alzheimer's disease (AD) is histopathologically characterized by Aβ plaques and the accumulation of hyperphosphorylated Tau species, the latter also constituting key hallmarks of primary tauopathies. Whereas Aβ is produced by amyloidogenic APP processing, APP processing along the competing nonamyloidogenic pathway results in the secretion of neurotrophic and synaptotrophic APPsα. Recently, we demonstrated that APPsα has therapeutic effects in transgenic AD model mice and rescues Aβ-dependent impairments. Here, we examined the potential of APPsα to mitigate Tau-induced synaptic deficits in P301S mice (both sexes), a widely used mouse model of tauopathy. Analysis of synaptic plasticity revealed an aberrantly increased LTP in P301S mice that could be normalized by acute application of nanomolar amounts of APPsα to hippocampal slices, indicating a homeostatic function of APPsα on a rapid time scale. Further, AAV-mediated in vivo expression of APPsα restored normal spine density of CA1 neurons even at stages of advanced Tau pathology not only in P301S mice, but also in independent THY-Tau22 mice. Strikingly, when searching for the mechanism underlying aberrantly increased LTP in P301S mice, we identified an early and progressive loss of major GABAergic interneuron subtypes in the hippocampus of P301S mice, which may lead to reduced GABAergic inhibition of principal cells. Interneuron loss was paralleled by deficits in nest building, an innate behavior highly sensitive to hippocampal impairments. Together, our findings indicate that APPsα has therapeutic potential for Tau-mediated synaptic dysfunction and suggest that loss of interneurons leads to disturbed neuronal circuits that compromise synaptic plasticity as well as behavior.SIGNIFICANCE STATEMENT Our findings indicate, for the first time, that APPsα has the potential to rescue Tau-induced spine loss and abnormal synaptic plasticity. Thus, APPsα might have therapeutic potential not only because of its synaptotrophic functions, but also its homeostatic capacity for neuronal network activity. Hence, APPsα is one of the few molecules which has proven therapeutic effects in mice, both for Aβ- and Tau-dependent synaptic impairments and might therefore have therapeutic potential for patients suffering from AD or primary tauopathies. Furthermore, we found in P301S mice a pronounced reduction of inhibitory interneurons as the earliest pathologic event preceding the accumulation of hyperphosphorylated Tau species. This loss of interneurons most likely disturbs neuronal circuits that are important for synaptic plasticity and behavior.
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Affiliation(s)
- Charlotte S Bold
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | - Danny Baltissen
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | - Susann Ludewig
- TU Braunschweig, Zoological Institute, Braunschweig, 38106, Germany
- Helmholtz Centre for Infection Research, Neuroinflammation and Neurodegeneration Group, Braunschweig, 38124, Germany
| | - Michaela K Back
- Institute of Pathophysiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, 55128, Germany
| | - Jennifer Just
- TU Braunschweig, Zoological Institute, Braunschweig, 38106, Germany
| | - Lara Kilian
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | - Susanne Erdinger
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | - Marija Banicevic
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | - Lena Rehra
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | - Fadi Almouhanna
- Institute of Physiology and Pathophysiology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | - Martina Nigri
- Institute of Anatomy, University of Zurich, Zurich, 8057, Switzerland
| | - David P Wolfer
- Institute of Anatomy, University of Zurich, Zurich, 8057, Switzerland
- Institute of Human Movement Sciences and Sport, ETH Zurich, Zurich, Switzerland
| | - Roman Spilger
- BioQuant Center, Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg and DKFZ, Heidelberg, 69120, Germany
| | - Karl Rohr
- BioQuant Center, Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg and DKFZ, Heidelberg, 69120, Germany
| | - Oliver Kann
- Institute of Physiology and Pathophysiology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | | | - Jakob von Engelhardt
- Institute of Pathophysiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, 55128, Germany
| | - Martin Korte
- TU Braunschweig, Zoological Institute, Braunschweig, 38106, Germany
- Helmholtz Centre for Infection Research, Neuroinflammation and Neurodegeneration Group, Braunschweig, 38124, Germany
| | - Ulrike C Müller
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
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8
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Martinsson I, Quintino L, Garcia MG, Konings SC, Torres-Garcia L, Svanbergsson A, Stange O, England R, Deierborg T, Li JY, Lundberg C, Gouras GK. Aβ/Amyloid Precursor Protein-Induced Hyperexcitability and Dysregulation of Homeostatic Synaptic Plasticity in Neuron Models of Alzheimer’s Disease. Front Aging Neurosci 2022; 14:946297. [PMID: 35928998 PMCID: PMC9344931 DOI: 10.3389/fnagi.2022.946297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/16/2022] [Indexed: 11/13/2022] Open
Abstract
Alzheimer’s disease (AD) is increasingly seen as a disease of synapses and diverse evidence has implicated the amyloid-β peptide (Aβ) in synapse damage. The molecular and cellular mechanism(s) by which Aβ and/or its precursor protein, the amyloid precursor protein (APP) can affect synapses remains unclear. Interestingly, early hyperexcitability has been described in human AD and mouse models of AD, which precedes later hypoactivity. Here we show that neurons in culture with either elevated levels of Aβ or with human APP mutated to prevent Aβ generation can both induce hyperactivity as detected by elevated calcium transient frequency and amplitude. Since homeostatic synaptic plasticity (HSP) mechanisms normally maintain a setpoint of activity, we examined whether HSP was altered in AD transgenic neurons. Using methods known to induce HSP, we demonstrate that APP protein levels are regulated by chronic modulation of activity and that AD transgenic neurons have an impaired adaptation of calcium transients to global changes in activity. Further, AD transgenic compared to WT neurons failed to adjust the length of their axon initial segments (AIS), an adaptation known to alter excitability. Thus, we show that both APP and Aβ influence neuronal activity and that mechanisms of HSP are disrupted in primary neuron models of AD.
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Affiliation(s)
- Isak Martinsson
- Experimental Dementia Research Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
- Experimental Neuroinflammation Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
- *Correspondence: Isak Martinsson,
| | - Luis Quintino
- CNS Gene Therapy, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Megg G. Garcia
- Experimental Dementia Research Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
- Experimental Neuroinflammation Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Sabine C. Konings
- Experimental Dementia Research Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Laura Torres-Garcia
- Experimental Dementia Research Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
- Neural Plasticity and Repair, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Alexander Svanbergsson
- Neural Plasticity and Repair, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Oliver Stange
- Experimental Dementia Research Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Rebecca England
- Experimental Dementia Research Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Tomas Deierborg
- Experimental Neuroinflammation Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Jia-Yi Li
- Neural Plasticity and Repair, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Cecilia Lundberg
- CNS Gene Therapy, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Gunnar K. Gouras
- Experimental Dementia Research Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
- Gunnar K. Gouras,
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9
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Cho Y, Bae HG, Okun E, Arumugam TV, Jo DG. Physiology and pharmacology of amyloid precursor protein. Pharmacol Ther 2022; 235:108122. [PMID: 35114285 DOI: 10.1016/j.pharmthera.2022.108122] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/17/2022] [Accepted: 01/25/2022] [Indexed: 02/06/2023]
Abstract
Amyloid precursor protein (APP) is an evolutionarily conserved transmembrane protein and a well-characterized precursor protein of amyloid-beta (Aβ) peptides, which accumulate in the brains of individuals with Alzheimer's disease (AD)-related pathologies. Aβ has been extensively investigated since the amyloid hypothesis in AD was proposed. Besides Aβ, previous studies on APP and its proteolytic cleavage products have suggested their diverse pathological and physiological functions. However, their roles still have not been thoroughly understood. In this review, we extensively discuss the evolutionarily-conserved biology of APP, including its structure and processing pathway, as well as recent findings on the physiological roles of APP and its fragments in the central nervous system and peripheral nervous system. We have also elaborated upon the current status of APP-targeted therapeutic approaches for AD treatment by discussing inhibitors of several proteases participating in APP processing, including α-, β-, and γ-secretases. Finally, we have highlighted the future perspectives pertaining to further research and the potential clinical role of APP.
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Affiliation(s)
- Yoonsuk Cho
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, South Korea
| | - Han-Gyu Bae
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, South Korea
| | - Eitan Okun
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan 5290002, Israel; The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 5290002, Israel; The Pauld Feder Laboratory on Alzheimer's Disease Research, Israel
| | - Thiruma V Arumugam
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, South Korea; School of Life Sciences, La Trobe University, Bundoora, Victoria, Australia.
| | - Dong-Gyu Jo
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, South Korea; Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul 06351, South Korea; Biomedical Institute for Convergence, Sungkyunkwan University, Suwon 16419, South Korea.
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10
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Papazoglou A, Arshaad MI, Henseler C, Daubner J, Broich K, Hescheler J, Ehninger D, Haenisch B, Weiergräber M. Ca v3 T-Type Voltage-Gated Ca 2+ Channels and the Amyloidogenic Environment: Pathophysiology and Implications on Pharmacotherapy and Pharmacovigilance. Int J Mol Sci 2022; 23:ijms23073457. [PMID: 35408817 PMCID: PMC8998330 DOI: 10.3390/ijms23073457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 12/07/2022] Open
Abstract
Voltage-gated Ca2+ channels (VGCCs) were reported to play a crucial role in neurotransmitter release, dendritic resonance phenomena and integration, and the regulation of gene expression. In the septohippocampal system, high- and low-voltage-activated (HVA, LVA) Ca2+ channels were shown to be involved in theta genesis, learning, and memory processes. In particular, HVA Cav2.3 R-type and LVA Cav3 T-type Ca2+ channels are expressed in the medial septum-diagonal band of Broca (MS-DBB), hippocampal interneurons, and pyramidal cells, and ablation of both channels was proven to severely modulate theta activity. Importantly, Cav3 Ca2+ channels contribute to rebound burst firing in septal interneurons. Consequently, functional impairment of T-type Ca2+ channels, e.g., in null mutant mouse models, caused tonic disinhibition of the septohippocampal pathway and subsequent enhancement of hippocampal theta activity. In addition, impairment of GABA A/B receptor transcription, trafficking, and membrane translocation was observed within the septohippocampal system. Given the recent findings that amyloid precursor protein (APP) forms complexes with GABA B receptors (GBRs), it is hypothesized that T-type Ca2+ current reduction, decrease in GABA receptors, and APP destabilization generate complex functional interdependence that can constitute a sophisticated proamyloidogenic environment, which could be of potential relevance in the etiopathogenesis of Alzheimer’s disease (AD). The age-related downregulation of T-type Ca2+ channels in humans goes together with increased Aβ levels that could further inhibit T-type channels and aggravate the proamyloidogenic environment. The mechanistic model presented here sheds new light on recent reports about the potential risks of T-type Ca2+ channel blockers (CCBs) in dementia, as observed upon antiepileptic drug application in the elderly.
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Affiliation(s)
- Anna Papazoglou
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Muhammad Imran Arshaad
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Christina Henseler
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Johanna Daubner
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Karl Broich
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (K.B.); (B.H.)
| | - Jürgen Hescheler
- Faculty of Medicine, Institute of Neurophysiology, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany;
- Center of Physiology and Pathophysiology, Faculty of Medicine, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany
| | - Dan Ehninger
- Translational Biogerontology, German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE), Venusberg-Campus 1/99, 53127 Bonn, Germany;
- German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE), Venusberg-Campus 1/99, 53127 Bonn, Germany
| | - Britta Haenisch
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (K.B.); (B.H.)
- German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE), Venusberg-Campus 1/99, 53127 Bonn, Germany
- Center for Translational Medicine, Medical Faculty, University of Bonn, 53113 Bonn, Germany
| | - Marco Weiergräber
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (K.B.); (B.H.)
- Faculty of Medicine, Institute of Neurophysiology, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany;
- Center of Physiology and Pathophysiology, Faculty of Medicine, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany
- Correspondence: ; Tel.: +49-228-99307-4358
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11
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Walia V, Kaushik D, Mittal V, Kumar K, Verma R, Parashar J, Akter R, Rahman MH, Bhatia S, Al-Harrasi A, Karthika C, Bhattacharya T, Chopra H, Ashraf GM. Delineation of Neuroprotective Effects and Possible Benefits of AntioxidantsTherapy for the Treatment of Alzheimer's Diseases by Targeting Mitochondrial-Derived Reactive Oxygen Species: Bench to Bedside. Mol Neurobiol 2021; 59:657-680. [PMID: 34751889 DOI: 10.1007/s12035-021-02617-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 10/19/2021] [Indexed: 12/25/2022]
Abstract
Alzheimer's disease (AD) is considered the sixth leading cause of death in elderly patients and is characterized by progressive neuronal degeneration and impairment in memory, language, etc. AD is characterized by the deposition of senile plaque, accumulation of fibrils, and neurofibrillary tangles (NFTs) which are responsible for neuronal degeneration. Amyloid-β (Aβ) plays a key role in the process of neuronal degeneration in the case of AD. It has been reported that Aβ is responsible for the production of reactive oxygen species (ROS), depletion of endogenous antioxidants, increase in intracellular Ca2+ which further increases mitochondria dysfunctions, oxidative stress, release of pro-apoptotic factors, neuronal apoptosis, etc. Thus, oxidative stress plays a key role in the pathogenesis of AD. Antioxidants are compounds that have the ability to counteract the oxidative damage conferred by ROS. Therefore, the antioxidant therapy may provide benefits and halt the progress of AD to advance stages by counteracting neuronal degeneration. However, despite the beneficial effects imposed by the antioxidants, the findings from the clinical studies suggested inconsistent results which might be due to poor study design, selection of the wrong antioxidant, inability of the molecule to cross the blood-brain barrier (BBB), treatment in the advanced state of disease, etc. The present review insights into the neuroprotective effects and limitations of the antioxidant therapy for the treatment of AD by targeting mitochondrial-derived ROS. This particular article will certainly help the researchers to search new avenues for the treatment of AD by utilizing mitochondrial-derived ROS-targeted antioxidant therapies.
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Affiliation(s)
- Vaibhav Walia
- SGT College of Pharmacy, SGT University, Gurugram, Haryana, India
| | - Deepak Kaushik
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, 124001, India
| | - Vineet Mittal
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, 124001, India
| | - Kuldeep Kumar
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab, India
- University Institute of Pharmaceutical Sciences (UIPS), Chandigarh University, Gharuan, Mohali, Punjab, India
| | - Ravinder Verma
- Department of Pharmacy, School of Medical and Allied Sciences, G.D. Goenka University, Gurugram, 122103, India
| | - Jatin Parashar
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, 124001, India
| | - Rokeya Akter
- Department of Pharmacy, Jagannath University, Sadarghat, Dhaka, 1100, Bangladesh
| | - Md Habibur Rahman
- Department of Pharmacy, Southeast University, Banani, Dhaka, 1213, Bangladesh.
| | - Saurabh Bhatia
- School of Health Science University of Petroleum and Energy Studies, Dehrandun, Uttarkhand, 248007, India
- Natural & Medical Sciences Research Center, University of Nizwa, 616 Birkat Al Mouz, P.O. Box 33, Nizwa, Oman
| | - Ahmed Al-Harrasi
- Natural & Medical Sciences Research Center, University of Nizwa, 616 Birkat Al Mouz, P.O. Box 33, Nizwa, Oman
| | - Chenmala Karthika
- Department of Pharmaceutics, JSS College of Pharmacy, JSS Academy of Higher Education & Research, The Nilgiris, Ooty, 643001, Tamil Nadu, India
| | - Tanima Bhattacharya
- College of Chemistry & Chemical Engineering, Hubei University, Wuhan, 430062, China
| | - Hitesh Chopra
- Chitkara College of Pharmacy, Chitkara University, Punjab, 140401, India
| | - Ghulam Md Ashraf
- Pre-Clinical Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
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12
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Ludewig S, Herrmann U, Michaelsen-Preusse K, Metzdorf K, Just J, Bold C, Müller UC, Korte M. APPsα rescues impaired Ca 2+ homeostasis in APP- and APLP2-deficient hippocampal neurons. Proc Natl Acad Sci U S A 2021; 118:e2011506118. [PMID: 34172567 PMCID: PMC8256088 DOI: 10.1073/pnas.2011506118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Alterations in Ca2+ homeostasis have been reported in several in vitro and in vivo studies using mice expressing the Alzheimer's disease-associated transgenes, presenilin and the amyloid precursor protein (APP). While intense research focused on amyloid-β-mediated functions on neuronal Ca2+ handling, the physiological role of APP and its close homolog APLP2 is still not fully clarified. We now elucidate a mechanism to show how APP and its homolog APLP2 control neuronal Ca2+ handling and identify especially the ectodomain APPsα as an essential regulator of Ca2+ homeostasis. Importantly, we demonstrate that the loss of APP and APLP2, but not APLP2 alone, impairs Ca2+ handling, the refill of the endoplasmic reticulum Ca2+ stores, and synaptic plasticity due to altered function and expression of the SERCA-ATPase and expression of store-operated Ca2+ channel-associated proteins Stim1 and Stim2. Long-term AAV-mediated expression of APPsα, but not acute application of the recombinant protein, restored physiological Ca2+ homeostasis and synaptic plasticity in APP/APLP2 cDKO cultures. Overall, our analysis reveals an essential role of the APP family and especially of the ectodomain APPsα in Ca2+ homeostasis, thereby highlighting its therapeutic potential.
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Affiliation(s)
- Susann Ludewig
- Department of Cellular Neurobiology Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
- Neuroinflammation and Neurodegeneration, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Ulrike Herrmann
- Department of Cellular Neurobiology Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Kristin Michaelsen-Preusse
- Department of Cellular Neurobiology Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Kristin Metzdorf
- Department of Cellular Neurobiology Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
- Neuroinflammation and Neurodegeneration, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Jennifer Just
- Department of Cellular Neurobiology Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Charlotte Bold
- Department of Functional Genomics, Institute for Pharmacy and Molecular Biotechnology, Heidelberg University, 69120 Heidelberg, Germany
| | - Ulrike C Müller
- Department of Functional Genomics, Institute for Pharmacy and Molecular Biotechnology, Heidelberg University, 69120 Heidelberg, Germany
| | - Martin Korte
- Department of Cellular Neurobiology Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany;
- Neuroinflammation and Neurodegeneration, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
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13
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Cascella R, Cecchi C. Calcium Dyshomeostasis in Alzheimer's Disease Pathogenesis. Int J Mol Sci 2021; 22:ijms22094914. [PMID: 34066371 PMCID: PMC8124842 DOI: 10.3390/ijms22094914] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/26/2021] [Accepted: 04/30/2021] [Indexed: 01/12/2023] Open
Abstract
Alzheimer’s disease (AD) is the most common age-related neurodegenerative disorder that is characterized by amyloid β-protein deposition in senile plaques, neurofibrillary tangles consisting of abnormally phosphorylated tau protein, and neuronal loss leading to cognitive decline and dementia. Despite extensive research, the exact mechanisms underlying AD remain unknown and effective treatment is not available. Many hypotheses have been proposed to explain AD pathophysiology; however, there is general consensus that the abnormal aggregation of the amyloid β peptide (Aβ) is the initial event triggering a pathogenic cascade of degenerating events in cholinergic neurons. The dysregulation of calcium homeostasis has been studied considerably to clarify the mechanisms of neurodegeneration induced by Aβ. Intracellular calcium acts as a second messenger and plays a key role in the regulation of neuronal functions, such as neural growth and differentiation, action potential, and synaptic plasticity. The calcium hypothesis of AD posits that activation of the amyloidogenic pathway affects neuronal Ca2+ homeostasis and the mechanisms responsible for learning and memory. Aβ can disrupt Ca2+ signaling through several mechanisms, by increasing the influx of Ca2+ from the extracellular space and by activating its release from intracellular stores. Here, we review the different molecular mechanisms and receptors involved in calcium dysregulation in AD and possible therapeutic strategies for improving the treatment.
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14
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Hampel H, Vassar R, De Strooper B, Hardy J, Willem M, Singh N, Zhou J, Yan R, Vanmechelen E, De Vos A, Nisticò R, Corbo M, Imbimbo BP, Streffer J, Voytyuk I, Timmers M, Monfared AAT, Irizarry M, Albala B, Koyama A, Watanabe N, Kimura T, Yarenis L, Lista S, Kramer L, Vergallo A. The β-Secretase BACE1 in Alzheimer's Disease. Biol Psychiatry 2021; 89:745-756. [PMID: 32223911 PMCID: PMC7533042 DOI: 10.1016/j.biopsych.2020.02.001] [Citation(s) in RCA: 322] [Impact Index Per Article: 107.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 01/29/2020] [Accepted: 02/05/2020] [Indexed: 01/18/2023]
Abstract
BACE1 (beta-site amyloid precursor protein cleaving enzyme 1) was initially cloned and characterized in 1999. It is required for the generation of all monomeric forms of amyloid-β (Aβ), including Aβ42, which aggregates into bioactive conformational species and likely initiates toxicity in Alzheimer's disease (AD). BACE1 concentrations and rates of activity are increased in AD brains and body fluids, thereby supporting the hypothesis that BACE1 plays a critical role in AD pathophysiology. Therefore, BACE1 is a prime drug target for slowing down Aβ production in early AD. Besides the amyloidogenic pathway, BACE1 has other substrates that may be important for synaptic plasticity and synaptic homeostasis. Indeed, germline and adult conditional BACE1 knockout mice display complex neurological phenotypes. Despite BACE1 inhibitor clinical trials conducted so far being discontinued for futility or safety reasons, BACE1 remains a well-validated therapeutic target for AD. A safe and efficacious compound with high substrate selectivity as well as a more accurate dose regimen, patient population, and disease stage may yet be found. Further research should focus on the role of Aβ and BACE1 in physiological processes and key pathophysiological mechanisms of AD. The functions of BACE1 and the homologue BACE2, as well as the biology of Aβ in neurons and glia, deserve further investigation. Cellular and molecular studies of BACE1 and BACE2 knockout mice coupled with biomarker-based human research will help elucidate the biological functions of these important enzymes and identify their substrates and downstream effects. Such studies will have critical implications for BACE1 inhibition as a therapeutic approach for AD.
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Affiliation(s)
- Harald Hampel
- Neurology Business Group, Eisai Inc., Woodcliff Lake, New Jersey; Sorbonne University, GRC No. 21, Alzheimer Precision Medicine, Pitié-Salpêtrière Hospital, Paris, France.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Andrea Vergallo
- Neurology Business Group, Eisai Inc., Woodcliff Lake, New Jersey; Sorbonne University, GRC No. 21, Alzheimer Precision Medicine, Pitié-Salpêtrière Hospital, Paris, France; Institute of Memory and Alzheimer's Disease, Department of Neurology, Pitié-Salpêtrière Hospital, Paris, France; Brain & Spine Institute, INSERM U 1127, CNRS UMR 7225, Paris, France.
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15
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Feng M, Song Y, Chen SH, Zhang Y, Zhou R. Molecular mechanism of secreted amyloid-β precursor protein in binding and modulating GABA BR1a. Chem Sci 2021; 12:6107-6116. [PMID: 33996007 PMCID: PMC8098695 DOI: 10.1039/d0sc06946a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A recent phenomenal study discovered that the extension domain of secreted amyloid-β precursor protein (sAPP) can bind to the intrinsically disordered sushi 1 domain of the γ-aminobutyric acid type B receptor subunit 1a (GABABR1a) and modulate its synaptic transmission. The work provided an important structural foundation for the modulation of GABABR1a; however, the detailed molecular interaction mechanism, crucial for future drug design, remains elusive. Here, we further investigated the dynamical interactions between sAPP peptides and the natively unstructured sushi 1 domain using all-atom molecular dynamics simulations, for both the 17-residue sAPP peptide (APP 17-mer) and its minimally active 9 residue segment (APP 9-mer). We then explored mutations of the APP 9-mer with rigorous free energy perturbation (FEP) calculations. Our in silico mutagenesis studies revealed key residues (D4, W6, and W7) responsible for the binding with the sushi 1 domain. More importantly, one double mutation based on different vertebrate APP sequences from evolution exhibited a stronger binding (ΔΔG = −1.91 ± 0.66 kcal mol−1), indicating a potentially enhanced GABABR1a modulator. These large-scale simulations may provide new insights into the binding mechanism between sAPP and the sushi 1 domain, which could open new avenues in the development of future GABABR1a-specific therapeutics. A recent phenomenal study discovered that the extension domain of secreted amyloid-β precursor protein (sAPP) can bind to the intrinsically disordered sushi 1 domain of the γ-aminobutyric acid type B receptor subunit 1a (GABABR1a) and modulate its synaptic transmission.![]()
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Affiliation(s)
- Mei Feng
- Institute of Quantitative Biology, Shanghai Institute for Advanced Study, College of Life Sciences, Department of Physics, Zhejiang University Hangzhou 310027 China .,Lanzhou Center for Theoretical Physics, Key Laboratory of Theoretical Physics of Gansu Province, Lanzhou University Lanzhou Gansu 730000 China
| | - Yi Song
- Institute of Quantitative Biology, Shanghai Institute for Advanced Study, College of Life Sciences, Department of Physics, Zhejiang University Hangzhou 310027 China
| | - Serena H Chen
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory Oak Ridge TN 37830 USA
| | - Yuanzhao Zhang
- Center for Applied Mathematics, Cornell University Ithaca NY 14583 USA
| | - Ruhong Zhou
- Institute of Quantitative Biology, Shanghai Institute for Advanced Study, College of Life Sciences, Department of Physics, Zhejiang University Hangzhou 310027 China .,Department of Chemistry, Columbia University New York NY 10027 USA
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16
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Chen M, Chen Y, Huo Q, Wang L, Tan S, Misrani A, Jiang J, Chen J, Chen S, Zhang J, Tabassum S, Wang J, Chen X, Long C, Yang L. Enhancing GABAergic signaling ameliorates aberrant gamma oscillations of olfactory bulb in AD mouse models. Mol Neurodegener 2021; 16:14. [PMID: 33663578 PMCID: PMC7934466 DOI: 10.1186/s13024-021-00434-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 02/16/2021] [Indexed: 12/13/2022] Open
Abstract
Background Before the deposition of amyloid-beta plaques and the onset of learning memory deficits, patients with Alzheimer’s disease (AD) experience olfactory dysfunction, typified by a reduced ability to detect, discriminate, and identify odors. Rodent models of AD, such as the Tg2576 and APP/PS1 mice, also display impaired olfaction, accompanied by aberrant in vivo or in vitro gamma rhythms in the olfactory pathway. However, the mechanistic relationships between the electrophysiological, biochemical and behavioral phenomena remain unclear. Methods To address the above issues in AD models, we conducted in vivo measurement of local field potential (LFP) with a combination of in vitro electro-olfactogram (EOG), whole-cell patch and field recordings to evaluate oscillatory and synaptic function and pharmacological regulation in the olfactory pathway, particularly in the olfactory bulb (OB). Levels of protein involved in excitation and inhibition of the OB were investigated by western blotting and fluorescence staining, while behavioral studies assessed olfaction and memory function. Results LFP measurements demonstrated an increase in gamma oscillations in the OB accompanied by altered olfactory behavior in both APP/PS1 and 3xTg mice at 3–5 months old, i.e. an age before the onset of plaque formation. Fewer olfactory sensory neurons (OSNs) and a reduced EOG contributed to a decrease in the excitatory responses of M/T cells, suggesting a decreased ability of M/T cells to trigger interneuron GABA release indicated by altered paired-pulse ratio (PPR), a presynaptic parameter. Postsynaptically, there was a compensatory increase in levels of GABAAR α1 and β3 subunits and subsequent higher amplitude of inhibitory responses. Strikingly, the GABA uptake inhibitor tiagabine (TGB) ameliorated abnormal gamma oscillations and levels of GABAAR subunits, suggesting a potential therapeutic strategy for early AD symptoms. These findings reveal increased gamma oscillations in the OB as a core indicator prior to onset of AD and uncover mechanisms underlying aberrant gamma activity in the OB. Conclusions This study suggests that the concomitant dysfunction of both olfactory behavior and gamma oscillations have important implications for early AD diagnosis: in particular, awareness of aberrant GABAergic signaling mechanisms might both aid diagnosis and suggest therapeutic strategies for olfactory damage in AD. Supplementary Information The online version contains supplementary material available at 10.1186/s13024-021-00434-7.
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Affiliation(s)
- Ming Chen
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou, 510006, China.,Department of Pharmacology, Key Laboratory of Anti-inflammatory and Immunopharmacology, School of Basic Medical Sciences, Anhui Medical University, Hefei, 230032, China
| | - Yunan Chen
- School of Life Sciences, South China Normal University, Guangzhou, 510631, China.,Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, China
| | - Qingwei Huo
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Lei Wang
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou, 510006, China
| | - Shuyi Tan
- School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Afzal Misrani
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou, 510006, China
| | - Jinxiang Jiang
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou, 510006, China
| | - Jian Chen
- School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Shiyuan Chen
- School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Jiawei Zhang
- Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, China
| | - Sidra Tabassum
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou, 510006, China
| | - Jichen Wang
- School of Psychology and Center for Studies of Psychological Application, South China Normal University, Guangzhou, 510631, China
| | - Xi Chen
- School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Cheng Long
- School of Life Sciences, South China Normal University, Guangzhou, 510631, China.,Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, China
| | - Li Yang
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou, 510006, China.
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17
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Shields LY, Li H, Nguyen K, Kim H, Doric Z, Garcia JH, Gill TM, Haddad D, Vossel K, Calvert M, Nakamura K. Mitochondrial fission is a critical modulator of mutant APP-induced neural toxicity. J Biol Chem 2021; 296:100469. [PMID: 33639169 PMCID: PMC8042169 DOI: 10.1016/j.jbc.2021.100469] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 02/17/2021] [Accepted: 02/23/2021] [Indexed: 11/30/2022] Open
Abstract
Alterations in mitochondrial fission may contribute to the pathophysiology of several neurodegenerative diseases, including Alzheimer's disease (AD). However, we understand very little about the normal functions of fission or how fission disruption may interact with AD-associated proteins to modulate pathogenesis. Here we show that loss of the central mitochondrial fission protein dynamin-related protein 1 (Drp1) in CA1 and other forebrain neurons markedly worsens the learning and memory of mice expressing mutant human amyloid precursor protein (hAPP) in neurons. In cultured neurons, Drp1KO and hAPP converge to produce mitochondrial Ca2+ (mitoCa2+) overload, despite decreasing mitochondria-associated ER membranes (MAMs) and cytosolic Ca2+. This mitoCa2+ overload occurs independently of ATP levels. These findings reveal a potential mechanism by which mitochondrial fission protects against hAPP-driven pathology.
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Affiliation(s)
- Lauren Y Shields
- Gladstone Institute of Neurological Disease, San Francisco, California, USA; Graduate Programs in Neuroscience and Biomedical Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Huihui Li
- Gladstone Institute of Neurological Disease, San Francisco, California, USA
| | - Kevin Nguyen
- Gladstone Institute of Neurological Disease, San Francisco, California, USA
| | - Hwajin Kim
- Gladstone Institute of Neurological Disease, San Francisco, California, USA
| | - Zak Doric
- Gladstone Institute of Neurological Disease, San Francisco, California, USA; Graduate Programs in Neuroscience and Biomedical Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Joseph H Garcia
- Gladstone Institute of Neurological Disease, San Francisco, California, USA
| | - T Michael Gill
- Gladstone Institute of Neurological Disease, San Francisco, California, USA
| | - Dominik Haddad
- Gladstone Institute of Neurological Disease, San Francisco, California, USA
| | - Keith Vossel
- Gladstone Institute of Neurological Disease, San Francisco, California, USA
| | - Meredith Calvert
- Gladstone Institute of Neurological Disease, San Francisco, California, USA
| | - Ken Nakamura
- Gladstone Institute of Neurological Disease, San Francisco, California, USA; Department of Neurology, University of California, San Francisco, San Francisco, California, USA; Graduate Programs in Neuroscience and Biomedical Sciences, University of California, San Francisco, San Francisco, California, USA.
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18
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Fahanik-Babaei J, Baluchnejadmojarad T, Roghani M. Differential Effect of Amyloid Beta1-40 on Short-term and Long-term Plasticity in Dentate Gyrus of a Rat Model of Alzheimer Disease. Basic Clin Neurosci 2021; 11:517-524. [PMID: 33613890 PMCID: PMC7878034 DOI: 10.32598/bcn.9.10.190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 06/10/2018] [Accepted: 07/24/2018] [Indexed: 11/24/2022] Open
Abstract
Introduction: Synaptic plasticity is inappropriately affected by neurodegenerative diseases, including Alzheimer Disease (AD). In this study, we examined the effect of intrahippocampal amyloid-beta (Aβ1-40) on dentate gyrus Long-term Potentiation (LTP) and presynaptic short-term plasticity in a rat model of AD. Methods: The experimental groups in this research included the control with no treatment, sham-operated receiving the vehicle (normal saline), and Aβ-lesioned groups. For modeling AD, aggregated Aβ1-40 (10 μg/2 μl on each side) was injected into the hippocampal CA1. Three weeks later, Population Spike (PS) amplitude and slope ratios were determined at different Inter-pulse Intervals (IPI) of 10, 20, 30, and 50 ms as a valid indicator of the short-term presynaptic facilitation and/or depression. In addition, PS amplitude and slope were taken as an index of long-term synaptic plasticity after application of High-frequency Stimulation (HFS) to induce LTP in the medial perforant-dentate gyrus pathway. Results: No significant differences were noted amongst the experimental groups regarding fEPSP slope and paired-pulse indices as indicators of short-term plasticity. In contrast, fEPSP slope and PS amplitude significantly decreased following the application of HFS in Aβ-injected group. In addition, there was no significant difference between the control and sham-operated groups regarding the mentioned parameters. Conclusion: Findings of this study clearly demonstrated that microinjection of Aβ1-40 into the CA1 could impair LTP in dentate gyrus but could not modify short-term plasticity.
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Affiliation(s)
| | - Tourandokht Baluchnejadmojarad
- Physiology Research Center, Iran University of Medical Sciences, Tehran, Iran.,Department of Physiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mehrdad Roghani
- Neurophysiology Research Center, Shahed University, Tehran, Iran
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19
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Huo Q, Tabassum S, Chen M, Sun M, Deng Y, Zheng X, Li Y, Chen J, Long C, Yang L. Amyloid-β Protein Precursor Deficiency Changes Neuronal Electrical Activity and Levels of Mitochondrial Proteins in the Medial Prefrontal Cortex. J Alzheimers Dis 2021; 81:1469-1482. [PMID: 33935084 DOI: 10.3233/jad-201557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Neuropathological features of Alzheimer's disease are characterized by the deposition of amyloid-β (Aβ) plaques and impairments in synaptic activity and memory. However, we know little about the physiological role of amyloid-β protein precursor (AβPP) from which Aβ derives. OBJECTIVE Evaluate APP deficiency induced alterations in neuronal electrical activity and mitochondrial protein expression. METHODS Utilizing electrophysiological, biochemical, pharmacological, and behavioral tests, we revealed aberrant local field potential (LFP), extracellular neuronal firing and levels of mitochondrial proteins. RESULT We show that APP knockout (APP-/-) leads to increased gamma oscillations in the medial prefrontal cortex (mPFC) at 1-2 months old, which can be restored by baclofen (Bac), a γ-aminobutyric acid type B receptor (GABABR) agonist. A higher dose and longer exposure time is required for Bac to suppress neuronal firing in APP-/- mice than in wild type animals, indicating enhanced GABABR mediated activity in the mPFC of APP-/- mice. In line with increased GABABR function, the glutamine synthetase inhibitor, L-methionine sulfonate, significantly increases GABABR levels in the mPFC of APP-/- mice and this is associated with a significantly lower incidence of death. The results suggest that APP-/- mice developed stronger GABABR mediated inhibition. Using HEK 293 as an expression system, we uncover that AβPP functions to suppress GABABR expression. Furthermore, APP-/- mice show abnormal expression of several mitochondrial proteins. CONCLUSION APP deficiency leads to both abnormal network activity involving defected GABABR and mitochondrial dysfunction, suggesting critical role of AβPP in synaptic and network function.
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Affiliation(s)
- Qingwei Huo
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou, China
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Sidra Tabassum
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou, China
| | - Ming Chen
- Department of Pharmacology, Key Laboratory of Anti-inflammatory and Immunopharmacology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Mengyao Sun
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Yueming Deng
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xingzhi Zheng
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Yi Li
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Jian Chen
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Cheng Long
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Li Yang
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou, China
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20
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Sun BL, Li WW, Wang J, Xu YL, Sun HL, Tian DY, Wang YJ, Yao XQ. Gut Microbiota Alteration and Its Time Course in a Tauopathy Mouse Model. J Alzheimers Dis 2020; 70:399-412. [PMID: 31177213 DOI: 10.3233/jad-181220] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Emerging evidence suggests that gut microbiota dysbiosis plays a role in neurodegenerative disorders. However, whether the composition and diversity of the gut microbiota are altered in tauopathies remains largely unknown. This study was aimed to examine the diversity and composition of the gut microbiota in tauopathies, as well as the correlation with pathological changes in the brain. We collected fecal samples from 32 P301L tau transgenic mice and 32 age- and gender-matched littermate mice at different ages. The 16S ribosomal RNA sequencing technique was used to analyze the microbiota composition in feces. Brain tau pathology levels were measured by immunohistochemistry. The diversity and composition of the gut microbiota significantly changed with aging. At the phylum level, the relative abundance of Bacteroidetes was increased, while Firmicutes were decreased in P301L mice compared with that in Wt mice after 3 months of age. In addition, Actinobacteria was decreased in P301L mice at 3 and 6 months of age, meanwhile Tenericutes was decreased in P301L mice at 10 months of age. Moreover, several specific macrobiota were highly associated with the levels of AT8-tau or pT231-tau protein in the brain. Our findings suggest that gut microbiota changed with aging, as well as in the tauopathy mice model. Modulation of the gut microbiota may be a potential strategy for treatment of tauopathy.
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Affiliation(s)
- Bin-Lu Sun
- Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Wei-Wei Li
- Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Jun Wang
- Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Ya-Li Xu
- Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Hao-Lun Sun
- Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Ding-Yuan Tian
- Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Yan-Jiang Wang
- Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China.,State Key Laboratory of Trauma, Burn and Combined Injury, Third Military Medical University, Chongqing, China.,Centre for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Science, Beijing, China
| | - Xiu-Qing Yao
- Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China
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21
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Harris SS, Wolf F, De Strooper B, Busche MA. Tipping the Scales: Peptide-Dependent Dysregulation of Neural Circuit Dynamics in Alzheimer’s Disease. Neuron 2020; 107:417-435. [DOI: 10.1016/j.neuron.2020.06.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/24/2020] [Accepted: 06/01/2020] [Indexed: 02/07/2023]
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22
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Schrank S, Barrington N, Stutzmann GE. Calcium-Handling Defects and Neurodegenerative Disease. Cold Spring Harb Perspect Biol 2020; 12:a035212. [PMID: 31427373 PMCID: PMC7328457 DOI: 10.1101/cshperspect.a035212] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Calcium signaling is critical to neuronal function and regulates highly diverse processes such as gene transcription, energy production, protein handling, and synaptic structure and function. Because there are many common underlying calcium-mediated pathological features observed across several neurological conditions, it has been proposed that neurodegenerative diseases have an upstream underlying calcium basis in their pathogenesis. With certain diseases such as Alzheimer's, Parkinson's, and Huntington's, specific sources of calcium dysregulation originating from distinct neuronal compartments or channels have been shown to have defined roles in initiating or sustaining disease mechanisms. Herein, we will review the major hallmarks of these diseases, and how they relate to calcium dysregulation. We will then discuss neuronal calcium handling throughout the neuron, with special emphasis on channels involved in neurodegeneration.
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Affiliation(s)
- Sean Schrank
- Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University, North Chicago, Illinois 60064
- School of Graduate and Postdoctoral Studies, Rosalind Franklin University, North Chicago, Illinois 60064
| | - Nikki Barrington
- Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University, North Chicago, Illinois 60064
- School of Graduate and Postdoctoral Studies, Rosalind Franklin University, North Chicago, Illinois 60064
- Chicago Medical School, Rosalind Franklin University, North Chicago, Illinois 60064
| | - Grace E Stutzmann
- Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University, North Chicago, Illinois 60064
- School of Graduate and Postdoctoral Studies, Rosalind Franklin University, North Chicago, Illinois 60064
- Chicago Medical School, Rosalind Franklin University, North Chicago, Illinois 60064
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23
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Chatzistavraki M, Papazafiri P, Efthimiopoulos S. Amyloid-β Protein Precursor Regulates Depolarization-Induced Calcium-Mediated Synaptic Signaling in Brain Slices. J Alzheimers Dis 2020; 76:1121-1133. [PMID: 32597808 DOI: 10.3233/jad-200290] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Coordinated calcium influx upon neuronal depolarization activates pathways that phosphorylate CaMKII, ERKs, and the transcription factor CREB and, therefore, expression of pro-survival and neuroprotective genes. Recent evidence indicates that amyloid-β protein precursor (AβPP) is trafficked to synapses and promotes their formation. At the synapse, AβPP interacts with synaptic proteins involved in vesicle exocytosis and affects calcium channel function. OBJECTIVE Herein, we examined the role of AβPP in depolarization-induced calcium-mediated signaling using acute cerebral slices from wild-type C57bl/6 mice and AβPP-/- C57bl/6 mice. METHODS Depolarization of acute cerebral slices from wild-type C57bl/6 and AβPP-/- C57bl/6 mice was used to induce synaptic signaling. Protein levels were examined by western blot and calcium dynamics were assessed using primary neuronal cultures. RESULTS In the absence of AβPP, decreased pCaMKII and pERKs levels were observed. This decrease was sensitive to the inhibition of N- and P/Q-type Voltage Gated Calcium Channels (N- and P/Q-VGCCs) by ω-conotoxin GVIA and ω-conotoxin MVIIC, respectively, but not to inhibition of L-type VGCCs by nifedipine. However, the absence of AβPP did not result in a statistically significant decrease of pCREB, which is a known substrate of pERKs. Finally, using calcium imaging, we found that down regulation of AβPP in cortical neurons results in a decreased response to depolarization and altered kinetics of calcium response. CONCLUSION AβPP regulates synaptic activity-mediated neuronal signaling by affecting N- and P/Q-VGCCs.
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Affiliation(s)
- Maria Chatzistavraki
- Department of Biology, Division of Animal and Human Physiology, National and Kapodistrian University of Athens, Panepistimiopolis, Ilisia, Greece
| | - Panagiota Papazafiri
- Department of Biology, Division of Animal and Human Physiology, National and Kapodistrian University of Athens, Panepistimiopolis, Ilisia, Greece
| | - Spiros Efthimiopoulos
- Department of Biology, Division of Animal and Human Physiology, National and Kapodistrian University of Athens, Panepistimiopolis, Ilisia, Greece
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24
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Xu Y, Zhao M, Han Y, Zhang H. GABAergic Inhibitory Interneuron Deficits in Alzheimer's Disease: Implications for Treatment. Front Neurosci 2020; 14:660. [PMID: 32714136 PMCID: PMC7344222 DOI: 10.3389/fnins.2020.00660] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/28/2020] [Indexed: 12/16/2022] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disorder characterized clinically by severe cognitive deficits and pathologically by amyloid plaques, neuronal loss, and neurofibrillary tangles. Abnormal amyloid β-protein (Aβ) deposition in the brain is often thought of as a major initiating factor in AD neuropathology. However, gamma-aminobutyric acid (GABA) inhibitory interneurons are resistant to Aβ deposition, and Aβ decreases synaptic glutamatergic transmission to decrease neural network activity. Furthermore, there is now evidence suggesting that neural network activity is aberrantly increased in AD patients and animal models due to functional deficits in and decreased activity of GABA inhibitory interneurons, contributing to cognitive deficits. Here we describe the roles played by excitatory neurons and GABA inhibitory interneurons in Aβ-induced cognitive deficits and how altered GABA interneurons regulate AD neuropathology. We also comprehensively review recent studies on how GABA interneurons and GABA receptors can be exploited for therapeutic benefit. GABA interneurons are an emerging therapeutic target in AD, with further clinical trials urgently warranted.
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Affiliation(s)
- Yilan Xu
- Neurodegeneration and Neuroregeneration Laboratory, Department of Basic Medicine, School of Medicine, Shaoxing University, Shaoxing, China
| | - Manna Zhao
- Neurodegeneration and Neuroregeneration Laboratory, Department of Basic Medicine, School of Medicine, Shaoxing University, Shaoxing, China
| | - Yuying Han
- Neurodegeneration and Neuroregeneration Laboratory, Department of Basic Medicine, School of Medicine, Shaoxing University, Shaoxing, China
| | - Heng Zhang
- Neurodegeneration and Neuroregeneration Laboratory, Department of Basic Medicine, School of Medicine, Shaoxing University, Shaoxing, China
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25
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Barthet G, Mulle C. Presynaptic failure in Alzheimer's disease. Prog Neurobiol 2020; 194:101801. [PMID: 32428558 DOI: 10.1016/j.pneurobio.2020.101801] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/24/2020] [Accepted: 04/03/2020] [Indexed: 12/14/2022]
Abstract
Synaptic loss is the best correlate of cognitive deficits in Alzheimer's disease (AD). Extensive experimental evidence also indicates alterations of synaptic properties at the early stages of disease progression, before synapse loss and neuronal degeneration. A majority of studies in mouse models of AD have focused on post-synaptic mechanisms, including impairment of long-term plasticity, spine structure and glutamate receptor-mediated transmission. Here we review the literature indicating that the synaptic pathology in AD includes a strong presynaptic component. We describe the evidence indicating presynaptic physiological functions of the major molecular players in AD. These include the amyloid precursor protein (APP) and the two presenilin (PS) paralogs PS1 or PS2, genetically linked to the early-onset form of AD, in addition to tau which accumulates in a pathological form in the AD brain. Three main mechanisms participating in presynaptic functions are highlighted. APP fragments bind to presynaptic receptors (e.g. nAChRs and GABAB receptors), presenilins control Ca2+ homeostasis and Ca2+-sensors, and tau regulates the localization of presynaptic molecules and synaptic vesicles. We then discuss how impairment of these presynaptic physiological functions can explain or forecast the hallmarks of synaptic impairment and associated dysfunction of neuronal circuits in AD. Beyond the physiological roles of the AD-related proteins, studies in AD brains also support preferential presynaptic alteration. This review features presynaptic failure as a strong component of pathological mechanisms in AD.
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Affiliation(s)
- Gael Barthet
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, University of Bordeaux, France
| | - Christophe Mulle
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, University of Bordeaux, France.
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26
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Wang L, Yin YL, Liu XZ, Shen P, Zheng YG, Lan XR, Lu CB, Wang JZ. Current understanding of metal ions in the pathogenesis of Alzheimer's disease. Transl Neurodegener 2020; 9:10. [PMID: 32266063 PMCID: PMC7119290 DOI: 10.1186/s40035-020-00189-z] [Citation(s) in RCA: 199] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 03/11/2020] [Indexed: 02/07/2023] Open
Abstract
Background The homeostasis of metal ions, such as iron, copper, zinc and calcium, in the brain is crucial for maintaining normal physiological functions. Studies have shown that imbalance of these metal ions in the brain is closely related to the onset and progression of Alzheimer's disease (AD), the most common neurodegenerative disorder in the elderly. Main body Erroneous deposition/distribution of the metal ions in different brain regions induces oxidative stress. The metal ions imbalance and oxidative stress together or independently promote amyloid-β (Aβ) overproduction by activating β- or γ-secretases and inhibiting α-secretase, it also causes tau hyperphosphorylation by activating protein kinases, such as glycogen synthase kinase-3β (GSK-3β), cyclin-dependent protein kinase-5 (CDK5), mitogen-activated protein kinases (MAPKs), etc., and inhibiting protein phosphatase 2A (PP2A). The metal ions imbalances can also directly or indirectly disrupt organelles, causing endoplasmic reticulum (ER) stress; mitochondrial and autophagic dysfunctions, which can cause or aggravate Aβ and tau aggregation/accumulation, and impair synaptic functions. Even worse, the metal ions imbalance-induced alterations can reversely exacerbate metal ions misdistribution and deposition. The vicious cycles between metal ions imbalances and Aβ/tau abnormalities will eventually lead to a chronic neurodegeneration and cognitive deficits, such as seen in AD patients. Conclusion The metal ions imbalance induces Aβ and tau pathologies by directly or indirectly affecting multiple cellular/subcellular pathways, and the disrupted homeostasis can reversely aggravate the abnormalities of metal ions transportation/deposition. Therefore, adjusting metal balance by supplementing or chelating the metal ions may be potential in ameliorating AD pathologies, which provides new research directions for AD treatment.
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Affiliation(s)
- Lu Wang
- 1Key Laboratory of Brain Research of Henan Province, Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, 453003 China
| | - Ya-Ling Yin
- 1Key Laboratory of Brain Research of Henan Province, Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, 453003 China
| | - Xin-Zi Liu
- 1Key Laboratory of Brain Research of Henan Province, Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, 453003 China
| | - Peng Shen
- 1Key Laboratory of Brain Research of Henan Province, Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, 453003 China
| | - Yan-Ge Zheng
- 1Key Laboratory of Brain Research of Henan Province, Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, 453003 China
| | - Xin-Rui Lan
- 1Key Laboratory of Brain Research of Henan Province, Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, 453003 China
| | - Cheng-Biao Lu
- 1Key Laboratory of Brain Research of Henan Province, Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, 453003 China
| | - Jian-Zhi Wang
- 2Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 China
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27
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Aberrant mPFC GABAergic synaptic transmission and fear behavior in neuroligin-2 R215H knock-in mice. Brain Res 2020; 1730:146671. [DOI: 10.1016/j.brainres.2020.146671] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 01/10/2020] [Accepted: 01/12/2020] [Indexed: 11/19/2022]
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28
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Rice HC, Marcassa G, Chrysidou I, Horré K, Young-Pearse TL, Müller UC, Saito T, Saido TC, Vassar R, de Wit J, De Strooper B. Contribution of GABAergic interneurons to amyloid-β plaque pathology in an APP knock-in mouse model. Mol Neurodegener 2020; 15:3. [PMID: 31915042 PMCID: PMC6950898 DOI: 10.1186/s13024-019-0356-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 12/30/2019] [Indexed: 12/04/2022] Open
Abstract
The amyloid-β (Aβ) peptide, the primary constituent of amyloid plaques found in Alzheimer's disease (AD) brains, is derived from sequential proteolytic processing of the Amyloid Precursor Protein (APP). However, the contribution of different cell types to Aβ deposition has not yet been examined in an in vivo, non-overexpression system. Here, we show that endogenous APP is highly expressed in a heterogeneous subset of GABAergic interneurons throughout various laminae of the hippocampus, suggesting that these cells may have a profound contribution to AD plaque pathology. We then characterized the laminar distribution of amyloid burden in the hippocampus of an APP knock-in mouse model of AD. To examine the contribution of GABAergic interneurons to plaque pathology, we blocked Aβ production specifically in these cells using a cell type-specific knock-out of BACE1. We found that during early stages of plaque deposition, interneurons contribute to approximately 30% of the total plaque load in the hippocampus. The greatest contribution to plaque load (75%) occurs in the stratum pyramidale of CA1, where plaques in human AD cases are most prevalent and where pyramidal cell bodies and synaptic boutons from perisomatic-targeting interneurons are located. These findings reveal a crucial role of GABAergic interneurons in the pathology of AD. Our study also highlights the necessity of using APP knock-in models to correctly evaluate the cellular contribution to amyloid burden since APP overexpressing transgenic models drive expression in cell types according to the promoter and integration site and not according to physiologically relevant expression mechanisms.
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Affiliation(s)
- Heather C. Rice
- VIB Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Present Address: Department of Biochemistry and Molecular Biology, Oklahoma Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
| | - Gabriele Marcassa
- VIB Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Iordana Chrysidou
- VIB Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Katrien Horré
- VIB Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Tracy L. Young-Pearse
- Department of Neurology, Ann Romney Center for Neurologic Diseases, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA USA
| | - Ulrike C. Müller
- Department of Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Saitama, Japan
- Department of Neurocognitive Science, Nagoya City University Graduate School of Medical Science, Nagoya, Japan
| | - Takaomi C. Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Saitama, Japan
| | - Robert Vassar
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, USA
| | - Joris de Wit
- VIB Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Bart De Strooper
- VIB Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- UK-Dementia Research Institute at University College London, London, UK
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29
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Abstract
The Amyloid Precursor Protein (APP) is infamous for its proposed pivotal role in the pathogenesis of Alzheimer’s disease (AD). Much research on APP focusses on potential contributions to neurodegeneration, mostly based on mouse models with altered expression or mutated forms of APP. However, cumulative evidence from recent years indicates the indispensability of APP and its metabolites for normal brain physiology. APP contributes to the regulation of synaptic transmission, plasticity, and calcium homeostasis. It plays an important role during development and it exerts neuroprotective effects. Of particular importance is the soluble secreted fragment APPsα which mediates many of its physiological actions, often counteracting the effects of the small APP-derived peptide Aβ. Understanding the contribution of APP for normal functions of the nervous system is of high importance, both from a basic science perspective and also as a basis for generating new pathophysiological concepts and therapeutic approaches in AD. In this article, we review the physiological functions of APP and its metabolites, focusing on synaptic transmission, plasticity, calcium signaling, and neuronal network activity.
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Affiliation(s)
- Dimitri Hefter
- Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany.,RG Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Susann Ludewig
- Helmholtz Centre for Infection Research, Neuroinflammation and Neurodegeneration Group, Braunschweig, Germany.,Cellular Neurobiology, Zoological Institute, Technical University Braunschweig, Braunschweig, Germany
| | - Andreas Draguhn
- Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany
| | - Martin Korte
- Helmholtz Centre for Infection Research, Neuroinflammation and Neurodegeneration Group, Braunschweig, Germany.,Cellular Neurobiology, Zoological Institute, Technical University Braunschweig, Braunschweig, Germany
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30
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Jiang J, Zheng Y, Chen Y, Zahra A, Long C, Yang L. Exposure to prenatal antidepressant alters medial prefrontal-striatal synchronization in mice. Brain Res 2019; 1717:27-34. [DOI: 10.1016/j.brainres.2019.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 03/21/2019] [Accepted: 04/11/2019] [Indexed: 11/28/2022]
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31
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Vico Varela E, Etter G, Williams S. Excitatory-inhibitory imbalance in Alzheimer's disease and therapeutic significance. Neurobiol Dis 2019; 127:605-615. [DOI: 10.1016/j.nbd.2019.04.010] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 04/08/2019] [Accepted: 04/12/2019] [Indexed: 11/29/2022] Open
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32
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Tang BL. Amyloid Precursor Protein (APP) and GABAergic Neurotransmission. Cells 2019; 8:E550. [PMID: 31174368 PMCID: PMC6627941 DOI: 10.3390/cells8060550] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 05/25/2019] [Accepted: 06/06/2019] [Indexed: 12/16/2022] Open
Abstract
The amyloid precursor protein (APP) is the parent polypeptide from which amyloid-beta (Aβ) peptides, key etiological agents of Alzheimer's disease (AD), are generated by sequential proteolytic processing involving β- and γ-secretases. APP mutations underlie familial, early-onset AD, and the involvement of APP in AD pathology has been extensively studied. However, APP has important physiological roles in the mammalian brain, particularly its modulation of synaptic functions and neuronal survival. Recent works have now shown that APP could directly modulate γ-aminobutyric acid (GABA) neurotransmission in two broad ways. Firstly, APP is shown to interact with and modulate the levels and activity of the neuron-specific Potassium-Chloride (K+-Cl-) cotransporter KCC2/SLC12A5. The latter is key to the maintenance of neuronal chloride (Cl-) levels and the GABA reversal potential (EGABA), and is therefore important for postsynaptic GABAergic inhibition through the ionotropic GABAA receptors. Secondly, APP binds to the sushi domain of metabotropic GABAB receptor 1a (GABABR1a). In this regard, APP complexes and is co-transported with GABAB receptor dimers bearing GABABR1a to the axonal presynaptic plasma membrane. On the other hand, secreted (s)APP generated by secretase cleavages could act as a GABABR1a-binding ligand that modulates presynaptic vesicle release. The discovery of these novel roles and activities of APP in GABAergic neurotransmission underlies the physiological importance of APP in postnatal brain function.
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Affiliation(s)
- Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117597, Singapore.
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33
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Carter CJ. Autism genes and the leukocyte transcriptome in autistic toddlers relate to pathogen interactomes, infection and the immune system. A role for excess neurotrophic sAPPα and reduced antimicrobial Aβ. Neurochem Int 2019; 126:36-58. [PMID: 30862493 DOI: 10.1016/j.neuint.2019.03.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 02/22/2019] [Accepted: 03/06/2019] [Indexed: 12/20/2022]
Abstract
Prenatal and early childhood infections have been implicated in autism. Many autism susceptibility genes (206 Autworks genes) are localised in the immune system and are related to immune/infection pathways. They are enriched in the host/pathogen interactomes of 18 separate microbes (bacteria/viruses and fungi) and to the genes regulated by bacterial toxins, mycotoxins and Toll-like receptor ligands. This enrichment was also observed for misregulated genes from a microarray study of leukocytes from autistic toddlers. The upregulated genes from this leukocyte study also matched the expression profiles in response to numerous infectious agents from the Broad Institute molecular signatures database. They also matched genes related to sudden infant death syndrome and autism comorbid conditions (autoimmune disease, systemic lupus erythematosus, diabetes, epilepsy and cardiomyopathy) as well as to estrogen and thyrotropin responses and to those upregulated by different types of stressors including oxidative stress, hypoxia, endoplasmic reticulum stress, ultraviolet radiation or 2,4-dinitrofluorobenzene, a hapten used to develop allergic skin reactions in animal models. The oxidative/integrated stress response is also upregulated in the autism brain and may contribute to myelination problems. There was also a marked similarity between the expression signatures of autism and Alzheimer's disease, and 44 shared autism/Alzheimer's disease genes are almost exclusively expressed in the blood-brain barrier. However, in contrast to Alzheimer's disease, levels of the antimicrobial peptide beta-amyloid are decreased and the levels of the neurotrophic/myelinotrophic soluble APP alpha are increased in autism, together with an increased activity of α-secretase. sAPPα induces an increase in glutamatergic and a decrease in GABA-ergic synapses creating and excitatory/inhibitory imbalance that has also been observed in autism. A literature survey showed that multiple autism genes converge on APP processing and that many are able to increase sAPPalpha at the expense of beta-amyloid production. A genetically programmed tilt of this axis towards an overproduction of neurotrophic/gliotrophic sAPPalpha and underproduction of antimicrobial beta-amyloid may explain the brain overgrowth and myelination dysfunction, as well as the involvement of pathogens in autism.
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Affiliation(s)
- C J Carter
- PolygenicPathways, 41C Marina, Saint Leonard's on Sea, TN38 0BU, East Sussex, UK.
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34
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Rice HC, de Malmazet D, Schreurs A, Frere S, Van Molle I, Volkov AN, Creemers E, Vertkin I, Nys J, Ranaivoson FM, Comoletti D, Savas JN, Remaut H, Balschun D, Wierda KD, Slutsky I, Farrow K, De Strooper B, de Wit J. Secreted amyloid-β precursor protein functions as a GABA BR1a ligand to modulate synaptic transmission. Science 2019; 363:eaao4827. [PMID: 30630900 PMCID: PMC6366617 DOI: 10.1126/science.aao4827] [Citation(s) in RCA: 186] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/30/2018] [Accepted: 11/14/2018] [Indexed: 12/16/2022]
Abstract
Amyloid-β precursor protein (APP) is central to the pathogenesis of Alzheimer's disease, yet its physiological function remains unresolved. Accumulating evidence suggests that APP has a synaptic function mediated by an unidentified receptor for secreted APP (sAPP). Here we show that the sAPP extension domain directly bound the sushi 1 domain specific to the γ-aminobutyric acid type B receptor subunit 1a (GABABR1a). sAPP-GABABR1a binding suppressed synaptic transmission and enhanced short-term facilitation in mouse hippocampal synapses via inhibition of synaptic vesicle release. A 17-amino acid peptide corresponding to the GABABR1a binding region within APP suppressed in vivo spontaneous neuronal activity in the hippocampus of anesthetized Thy1-GCaMP6s mice. Our findings identify GABABR1a as a synaptic receptor for sAPP and reveal a physiological role for sAPP in regulating GABABR1a function to modulate synaptic transmission.
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Affiliation(s)
- Heather C Rice
- VIB Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Daniel de Malmazet
- Neuro-Electronics Research Flanders, Leuven, Belgium
- Department of Biology, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - An Schreurs
- Brain & Cognition, KU Leuven, Leuven, Belgium
| | - Samuel Frere
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Inge Van Molle
- VIB-VUB Structural Biology Research Center, Brussels, Belgium
| | - Alexander N Volkov
- VIB-VUB Structural Biology Research Center, Brussels, Belgium
- Jean Jeener NMR Centre, VUB, Brussels, Belgium
| | - Eline Creemers
- VIB Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Irena Vertkin
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Julie Nys
- VIB Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Fanomezana M Ranaivoson
- Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers University, NJ, USA
| | - Davide Comoletti
- Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers University, NJ, USA
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, NJ, USA
| | - Jeffrey N Savas
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Han Remaut
- VIB-VUB Structural Biology Research Center, Brussels, Belgium
| | | | - Keimpe D Wierda
- VIB Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Inna Slutsky
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Karl Farrow
- Neuro-Electronics Research Flanders, Leuven, Belgium
- Department of Biology, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- VIB, Leuven, Belgium
- imec, Leuven, Belgium
| | - Bart De Strooper
- VIB Center for Brain & Disease Research, Leuven, Belgium.
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- UK-Dementia Research Institute at University College London, UK
| | - Joris de Wit
- VIB Center for Brain & Disease Research, Leuven, Belgium.
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
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35
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Tropea D, Hardingham N, Millar K, Fox K. Mechanisms underlying the role of DISC1 in synaptic plasticity. J Physiol 2018; 596:2747-2771. [PMID: 30008190 PMCID: PMC6046077 DOI: 10.1113/jp274330] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 02/02/2018] [Indexed: 12/11/2022] Open
Abstract
Disrupted in schizophrenia 1 (DISC1) is an important hub protein, forming multimeric complexes by self-association and interacting with a large number of synaptic and cytoskeletal molecules. The synaptic location of DISC1 in the adult brain suggests a role in synaptic plasticity, and indeed, a number of studies have discovered synaptic plasticity impairments in a variety of different DISC1 mutants. This review explores the possibility that DISC1 is an important molecule for organizing proteins involved in synaptic plasticity and examines why mutations in DISC1 impair plasticity. It concentrates on DISC1's role in interacting with synaptic proteins, controlling dendritic structure and cellular trafficking of mRNA, synaptic vesicles and mitochondria. N-terminal directed mutations appear to impair synaptic plasticity through interactions with phosphodiesterase 4B (PDE4B) and hence protein kinase A (PKA)/GluA1 and PKA/cAMP response element-binding protein (CREB) signalling pathways, and affect spine structure through interactions with kalirin 7 (Kal-7) and Rac1. C-terminal directed mutations also impair plasticity possibly through altered interactions with lissencephaly protein 1 (LIS1) and nuclear distribution protein nudE-like 1 (NDEL1), thereby affecting developmental processes such as dendritic structure and spine maturation. Many of the same molecules involved in DISC1's cytoskeletal interactions are also involved in intracellular trafficking, raising the possibility that impairments in intracellular trafficking affect cytoskeletal development and vice versa. While the multiplicity of DISC1 protein interactions makes it difficult to pinpoint a single causal signalling pathway, we suggest that the immediate-term effects of N-terminal influences on GluA1, Rac1 and CREB, coupled with the developmental effects of C-terminal influences on trafficking and the cytoskeleton make up the two main branches of DISC1's effect on synaptic plasticity and dendritic spine stability.
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Affiliation(s)
- Daniela Tropea
- Neurospychiatric GeneticsTrinity Center for Health Sciences and Trinity College Institute of Neuroscience (TCIN)Trinity College DublinDublinIreland
| | - Neil Hardingham
- School of BiosciencesMuseum AvenueCardiff UniversityCardiffUK
| | - Kirsty Millar
- Centre for Genomic & Experimental MedicineMRC Institute of Genetics & Molecular MedicineWestern General HospitalUniversity of EdinburghCrewe RoadEdinburghUK
| | - Kevin Fox
- School of BiosciencesMuseum AvenueCardiff UniversityCardiffUK
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36
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Huo Q, Chen M, He Q, Zhang J, Li B, Jin K, Chen X, Long C, Yang L. Prefrontal Cortical GABAergic Dysfunction Contributes to Aberrant UP-State Duration in APP Knockout Mice. Cereb Cortex 2018; 27:4060-4072. [PMID: 27552836 DOI: 10.1093/cercor/bhw218] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 06/24/2016] [Indexed: 01/07/2023] Open
Abstract
Genetic and biochemical studies have focused on the role of amyloid β protein in the pathogenesis of Alzheimer's disease. In comparison, the physiological roles of its precursor protein, amyloid precursor protein (APP), in synaptic and network activity is less well studied. Using an APP knockout (APP-/-) mouse model, we show that the duration of UP state, which is a key feature of cortical synaptic integration occurring predominantly during slow-wave sleep, is significantly increased in the prefrontal cortex (PFC) in the absence of APP. This was accompanied by a specific reduction in the glutamine synthetase and tissue GABA content and sequential upregulation in the levels of GABABR expression. Pharmacological reinforcement of GABA signaling by application of either a GABA uptake inhibitor or an agonist of GABABR rescued the abnormality of UP-state duration and the former rescues altered GABABR expression as well. In addition to revealing an essential role of APP in the regulation of PFC network function, this study evidences the viability of GABA signaling pathway and its receptors, especially GABABRs, as a target for the treatment of aberrant neural network activity and thus information processing.
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Affiliation(s)
- Qingwei Huo
- School of Psychology South China Normal University, Guangzhou 510631, China.,School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Ming Chen
- School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Quansheng He
- School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Jiajia Zhang
- School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Bo Li
- School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Kai Jin
- School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Xi Chen
- School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Cheng Long
- School of Life Sciences, South China Normal University, Guangzhou 510631, China.,Brain Science Institute, South China Normal University, Guangzhou 510631, China
| | - Li Yang
- School of Psychology South China Normal University, Guangzhou 510631, China.,Brain Science Institute, South China Normal University, Guangzhou 510631, China.,Center for Studies of Psychological Application, South China Normal University, Guangzhou 510631, China.,Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou 510631, China
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37
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Human Brain-Derived Aβ Oligomers Bind to Synapses and Disrupt Synaptic Activity in a Manner That Requires APP. J Neurosci 2017; 37:11947-11966. [PMID: 29101243 DOI: 10.1523/jneurosci.2009-17.2017] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 09/19/2017] [Accepted: 09/29/2017] [Indexed: 12/20/2022] Open
Abstract
Compelling genetic evidence links the amyloid precursor protein (APP) to Alzheimer's disease (AD) and several theories have been advanced to explain the relationship. A leading hypothesis proposes that a small amphipathic fragment of APP, the amyloid β-protein (Aβ), self-associates to form soluble aggregates that impair synaptic and network activity. Here, we used the most disease-relevant form of Aβ, protein isolated from AD brain. Using this material, we show that the synaptotoxic effects of Aβ depend on expression of APP and that the Aβ-mediated impairment of synaptic plasticity is accompanied by presynaptic effects that disrupt the excitatory/inhibitory (E/I) balance. The net increase in the E/I ratio and inhibition of plasticity are associated with Aβ localizing to synapses and binding of soluble Aβ aggregates to synapses requires the expression of APP. Our findings indicate a role for APP in AD pathogenesis beyond the generation of Aβ and suggest modulation of APP expression as a therapy for AD.SIGNIFICANCE STATEMENT Here, we report on the plasticity-disrupting effects of amyloid β-protein (Aβ) isolated from Alzheimer's disease (AD) brain and the requirement of amyloid precursor protein (APP) for these effects. We show that Aβ-containing AD brain extracts block hippocampal LTP, augment glutamate release probability, and disrupt the excitatory/inhibitory balance. These effects are associated with Aβ localizing to synapses and genetic ablation of APP prevents both Aβ binding and Aβ-mediated synaptic dysfunctions. Our results emphasize the importance of APP in AD and should stimulate new studies to elucidate APP-related targets suitable for pharmacological manipulation.
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38
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Liu A, Zhang Y, Han L, He G, Xie W, Zhou Z, Jia Z. Regulation of Neurotransmitter Release by Amyloid Precursor Protein Through Synapsin Phosphorylation. Neurochem Res 2017; 44:683-691. [PMID: 29052089 DOI: 10.1007/s11064-017-2418-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 10/01/2017] [Accepted: 10/09/2017] [Indexed: 12/19/2022]
Abstract
Abnormal processing of amyloid precursor protein (APP) and aggregation of the Aβ peptide are known to play a key role in the pathogenesis of Alzheimer disease, but the function of endogenous APP under normal physiological conditions remains poorly understood. In this study, we investigated presynaptic changes in APP knockout (KO) mice. We demonstrate that both sucrose-induced neurotransmission and synaptic depletion in response to high frequency stimulation are significantly enhanced in APP KO compared to wild type littermates. In addition, the level of phosphorylated forms of synapsins, but not total synapsins, is elevated in the KO mice. Furthermore, we show that the inhibition of L-type calcium channels normalizes phosphorylated synapsins and slows down the high frequency induced synaptic depletion in APP KO mice. These results suggest a new mechanism by which APP regulates synaptic vesicle dynamics through synapsin-dependent phosphorylation.
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Affiliation(s)
- An Liu
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing, 210096, China
| | - Ying Zhang
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing, 210096, China
| | - Lifang Han
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing, 210096, China
| | - Guiqin He
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing, 210096, China
| | - Wei Xie
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing, 210096, China
| | - Zikai Zhou
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing, 210096, China
| | - Zhengping Jia
- Neurosciences & Mental Health, the Hospital for Sick Children, 555 University Ave., Toronto, ON, M5G 1X8, Canada. .,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
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Feng Y, Tang B, Chen M, Yang L. Whole-cell Currents Induced by Puff Application of GABA in Brain Slices. J Vis Exp 2017. [PMID: 29053689 DOI: 10.3791/56387] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Pharmacological administration is commonly used when conducting whole-cell patch-clamp recording in brain slices. One of the best methods of drug application during electrophysiological recording is the puff technique, which can be used to study the effect of pharmacological reagents on neuronal activities in brain slices. The greatest advantage of puff application is that the drug concentration around the recording site increases rapidly, thus preventing desensitization of membrane receptors. Successful use of puff application involves careful attention to the following elements: the concentration of the drug, the parameters of the puff micropipette, the distance between the tip of a puff micropipette and the neuron recorded, and the duration and pressure driving the puff (pounds per square inch, psi). This article describes a step-by-step procedure for recording whole-cell currents induced by puffing gamma-aminobutyric acid (GABA) onto a neuron of a prefrontal cortical slice. Notably, the same procedure can be applied with minor modifications to other brain areas such as the hippocampus and the striatum, and to different preparations, such as cell cultures.
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Affiliation(s)
- Yangjian Feng
- School of Psychology, South China Normal University; School of Life Sciences, South China Normal University
| | - Binliang Tang
- School of Psychology, South China Normal University; School of Life Sciences, South China Normal University
| | - Ming Chen
- School of Life Sciences, South China Normal University
| | - Li Yang
- School of Psychology, South China Normal University; Brain Science Institute, South China Normal University; Center for Studies of Psychological Application, South China Normal University; Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University;
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40
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Zhang J, Hao C, Jiang J, Feng Y, Chen X, Zheng Y, Liu J, Zhang Z, Long C, Yang L. The mechanisms underlying olfactory deficits in apolipoprotein E-deficient mice: focus on olfactory epithelium and olfactory bulb. Neurobiol Aging 2017; 62:20-33. [PMID: 29107844 DOI: 10.1016/j.neurobiolaging.2017.09.036] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 09/20/2017] [Accepted: 09/30/2017] [Indexed: 01/09/2023]
Abstract
Apolipoprotein E (ApoE) is highly expressed in the central nervous system including the olfactory epithelium (OE) and olfactory bulb (OB). ApoE induction is beneficial for Alzheimer's disease (AD) treatment, whereas ApoE deficiency results in impaired olfaction, but the timing and underlying molecular and cellular mechanisms of these effects remain unclear. Uncovering the mechanisms underlying olfactory dysfunction in ApoE-deficient mice might provide a potential avenue for the early diagnosis of AD. We used an ApoE knockout (ApoE-/-) mouse model and a cookie-finding test to reveal an olfactory deficit in 3- to 5-month-old, but not 1- to 2-month-old, ApoE-/- mice. Electrophysiological experiments indicated a significant decline in the electroolfactogram (EOG) amplitude, which was associated with an increase in rise time in ApoE-/- mice. Knockout mice also exhibited compromised olfactory adaptation, as well as a reduced number of mature olfactory sensory neurons in the OE. Local field potential recording in the OB showed that gamma oscillation power was enhanced, which might be attributed to an increase in GABAergic inhibition mediated by parvalbumin-expressing (PV) interneurons. This study demonstrates the critical involvement of ApoE in olfactory information processing in the OE and OB. ApoE deficiency results in olfaction deficits in mice as young as 3 months old, which has implications for AD pathogenesis.
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Affiliation(s)
- Jiajia Zhang
- School of Life Sciences, Guangzhou University, Guangzhou, China; School of Life Sciences and Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, China
| | - Caiyuan Hao
- School of Life Sciences and Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, China
| | - Jinxiang Jiang
- School of Psychology, South China Normal University, Guangzhou, China
| | - Yangjian Feng
- School of Life Sciences and Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, China
| | - Xi Chen
- School of Life Sciences and Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, China
| | - Ying Zheng
- School of Life Sciences and Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, China
| | - Jiawei Liu
- School of Life Sciences and Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, China
| | - Zhilin Zhang
- School of Life Sciences and Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, China
| | - Cheng Long
- School of Life Sciences and Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, China
| | - Li Yang
- School of Life Sciences, Guangzhou University, Guangzhou, China.
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41
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Amyloid Precursor Protein Protects Neuronal Network Function after Hypoxia via Control of Voltage-Gated Calcium Channels. J Neurosci 2017; 36:8356-71. [PMID: 27511009 DOI: 10.1523/jneurosci.4130-15.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 06/19/2016] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED Acute cerebral ischemia and chronic neurovascular diseases share various common mechanisms with neurodegenerative diseases, such as disturbed cellular calcium and energy homeostasis and accumulation of toxic metabolites. A link between these conditions may be constituted by amyloid precursor protein (APP), which plays a pivotal role in the pathogenesis of Alzheimer's disease, but has also been associated with the response to acute hypoxia and regulation of calcium homeostasis. We therefore studied hypoxia-induced loss of function and recovery upon reoxygenation in hippocampal slices of mice lacking APP (APP(-/-)) or selectively expressing its soluble extracellular domain (APPsα-KI). Transient hypoxia disrupted electrical activity at the network and cellular level. In mice lacking APP, these impairments were significantly more severe, showing increased rise of intracellular calcium, faster loss of function, and higher incidence of spreading depression. Likewise, functional recovery upon reoxygenation was much slower and less complete than in controls. Most of these deficits were rescued by selective expression of the soluble extracellular fragment APPsα, or by pharmacological block of L-type calcium channels. We conclude that APP supports neuronal resistance toward acute hypoxia. This effect is mediated by the secreted APPsα-domain and involves L-type calcium channels. SIGNIFICANCE STATEMENT Amyloid precursor protein (APP) is involved in the pathophysiology of Alzheimer's disease, but its normal function in the brain remains elusive. Here, we describe a neuroprotective role of the protein in acute hypoxia. Functional recovery of mouse hippocampal networks after transient reduction of oxygen supply was strongly impaired in animals lacking APP. Most protective effects are mediated by the soluble extracellular fragment APPsα and involve L-type calcium channels. Thus, APP contributes to calcium homeostasis in situations of metabolic stress. This finding may shed light on the physiological function of APP and may be important for understanding mechanisms of neurodegenerative diseases.
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42
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Not just amyloid: physiological functions of the amyloid precursor protein family. Nat Rev Neurosci 2017; 18:281-298. [PMID: 28360418 DOI: 10.1038/nrn.2017.29] [Citation(s) in RCA: 387] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyloid precursor protein (APP) gives rise to the amyloid-β peptide and thus has a key role in the pathogenesis of Alzheimer disease. By contrast, the physiological functions of APP and the closely related APP-like proteins (APLPs) remain less well understood. Studying these physiological functions has been challenging and has required a careful long-term strategy, including the analysis of different App-knockout and Aplp-knockout mice. In this Review, we summarize these findings, focusing on the in vivo roles of APP family members and their processing products for CNS development, synapse formation and function, brain injury and neuroprotection, as well as ageing. In addition, we discuss the implications of APP physiology for therapeutic approaches.
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Doshina A, Gourgue F, Onizuka M, Opsomer R, Wang P, Ando K, Tasiaux B, Dewachter I, Kienlen-Campard P, Brion JP, Gailly P, Octave JN, Pierrot N. Cortical cells reveal APP as a new player in the regulation of GABAergic neurotransmission. Sci Rep 2017; 7:370. [PMID: 28337033 PMCID: PMC5428293 DOI: 10.1038/s41598-017-00325-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 02/21/2017] [Indexed: 12/30/2022] Open
Abstract
The amyloid precursor protein (APP) modulates synaptic activity, resulting from the fine tuning of excitatory and inhibitory neurotransmission. GABAergic inhibitory neurotransmission is affected by modifications in intracellular chloride concentrations regulated by Na+-K+-2Cl- cotransporter 1 (NKCC1) and neuronal K+-Cl- cotransporter 2 (KCC2), allowing entrance and efflux of chloride, respectively. Modifications in NKCC1 and KCC2 expression during maturation of cortical cells induce a shift in GABAergic signaling. Here, we demonstrated that APP affects this GABA shift. Expression of APP in cortical cells decreased the expression of KCC2, without modifying NKCC1, eliciting a less inhibitory GABA response. Downregulation of KCC2 expression by APP was independent of the APP intracellular domain, but correlated with decreased expression of upstream stimulating factor 1 (USF1), a potent regulator of Slc12a5 gene expression (encoding KCC2). KCC2 was also downregulated in vivo following APP expression in neonatal mouse brain. These results argue for a key role of APP in the regulation of GABAergic neurotransmission.
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Affiliation(s)
- Anna Doshina
- Institute of Neuroscience, Université catholique de Louvain, 1200, Brussels, Belgium
| | - Florian Gourgue
- Institute of Neuroscience, Université catholique de Louvain, 1200, Brussels, Belgium
| | - Michiho Onizuka
- Institute of Neuroscience, Université catholique de Louvain, 1200, Brussels, Belgium
| | - Remi Opsomer
- Institute of Neuroscience, Université catholique de Louvain, 1200, Brussels, Belgium
| | - Peng Wang
- Institute of Neuroscience, Université catholique de Louvain, 1200, Brussels, Belgium
| | - Kunie Ando
- Laboratory of Histology and Neuropathology, Université libre de Bruxelles, 1070, Brussels, Belgium
| | - Bernadette Tasiaux
- Institute of Neuroscience, Université catholique de Louvain, 1200, Brussels, Belgium
| | - Ilse Dewachter
- Institute of Neuroscience, Université catholique de Louvain, 1200, Brussels, Belgium
| | | | - Jean-Pierre Brion
- Laboratory of Histology and Neuropathology, Université libre de Bruxelles, 1070, Brussels, Belgium
| | - Philippe Gailly
- Institute of Neuroscience, Université catholique de Louvain, 1200, Brussels, Belgium
| | - Jean-Noël Octave
- Institute of Neuroscience, Université catholique de Louvain, 1200, Brussels, Belgium.
| | - Nathalie Pierrot
- Institute of Neuroscience, Université catholique de Louvain, 1200, Brussels, Belgium
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Weingarten J, Weingarten M, Wegner M, Volknandt W. APP-A Novel Player within the Presynaptic Active Zone Proteome. Front Mol Neurosci 2017; 10:43. [PMID: 28265241 PMCID: PMC5316543 DOI: 10.3389/fnmol.2017.00043] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 02/07/2017] [Indexed: 11/13/2022] Open
Abstract
The amyloid precursor protein (APP) was discovered in the 1980s as the precursor protein of the amyloid A4 peptide. The amyloid A4 peptide, also known as A-beta (Aβ), is the main constituent of senile plaques implicated in Alzheimer's disease (AD). In association with the amyloid deposits, increasing impairments in learning and memory as well as the degeneration of neurons especially in the hippocampus formation are hallmarks of the pathogenesis of AD. Within the last decades much effort has been expended into understanding the pathogenesis of AD. However, little is known about the physiological role of APP within the central nervous system (CNS). Allocating APP to the proteome of the highly dynamic presynaptic active zone (PAZ) identified APP as a novel player within this neuronal communication and signaling network. The analysis of the hippocampal PAZ proteome derived from APP-mutant mice demonstrates that APP is tightly embedded in the underlying protein network. Strikingly, APP deletion accounts for major dysregulation within the PAZ proteome network. Ca2+-homeostasis, neurotransmitter release and mitochondrial function are affected and resemble the outcome during the pathogenesis of AD. The observed changes in protein abundance that occur in the absence of APP as well as in AD suggest that APP is a structural and functional regulator within the hippocampal PAZ proteome. Within this review article, we intend to introduce APP as an important player within the hippocampal PAZ proteome and to outline the impact of APP deletion on individual PAZ proteome subcommunities.
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Affiliation(s)
- Jens Weingarten
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Goethe University Frankfurt am Main, Germany
| | - Melanie Weingarten
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Goethe University Frankfurt am Main, Germany
| | - Martin Wegner
- Department of Molecular Bioinformatics, Goethe University Frankfurt am Main, Germany
| | - Walter Volknandt
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Goethe University Frankfurt am Main, Germany
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Hefter D, Draguhn A. APP as a Protective Factor in Acute Neuronal Insults. Front Mol Neurosci 2017; 10:22. [PMID: 28210211 PMCID: PMC5288400 DOI: 10.3389/fnmol.2017.00022] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 01/16/2017] [Indexed: 12/25/2022] Open
Abstract
Despite its key role in the molecular pathology of Alzheimer’s disease (AD), the physiological function of amyloid precursor protein (APP) is unknown. Increasing evidence, however, points towards a neuroprotective role of this membrane protein in situations of metabolic stress. A key observation is the up-regulation of APP following acute (stroke, cardiac arrest) or chronic (cerebrovascular disease) hypoxic-ischemic conditions. While this mechanism may increase the risk or severity of AD, APP by itself or its soluble extracellular fragment APPsα can promote neuronal survival. Indeed, different animal models of acute hypoxia-ischemia, traumatic brain injury (TBI) and excitotoxicity have revealed protective effects of APP or APPsα. The underlying mechanisms involve APP-mediated regulation of calcium homeostasis via NMDA receptors (NMDAR), voltage-gated calcium channels (VGCC) or internal calcium stores. In addition, APP affects the expression of survival- or apoptosis-related genes as well as neurotrophic factors. In this review, we summarize the current understanding of the neuroprotective role of APP and APPsα and possible implications for future research and new therapeutic strategies.
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Affiliation(s)
- Dimitri Hefter
- Institute of Physiology and Pathophysiology, Heidelberg UniversityHeidelberg, Germany; Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg UniversityMannheim, Germany
| | - Andreas Draguhn
- Institute of Physiology and Pathophysiology, Heidelberg University Heidelberg, Germany
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Ludewig S, Korte M. Novel Insights into the Physiological Function of the APP (Gene) Family and Its Proteolytic Fragments in Synaptic Plasticity. Front Mol Neurosci 2017; 9:161. [PMID: 28163673 PMCID: PMC5247455 DOI: 10.3389/fnmol.2016.00161] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/14/2016] [Indexed: 12/31/2022] Open
Abstract
The amyloid precursor protein (APP) is well known to be involved in the pathophysiology of Alzheimer's disease (AD) via its cleavage product amyloid ß (Aß). However, the physiological role of APP, its various proteolytic products and the amyloid precursor-like proteins 1 and 2 (APLP1/2) are still not fully clarified. Interestingly, it has been shown that learning and memory processes represented by functional and structural changes at synapses are altered in different APP and APLP1/2 mouse mutants. In addition, APP and its fragments are implicated in regulating synaptic strength further reinforcing their modulatory role at the synapse. While APLP2 and APP are functionally redundant, the exclusively CNS expressed APLP1, might have individual roles within the synaptic network. The proteolytic product of non-amyloidogenic APP processing, APPsα, emerged as a neurotrophic peptide that facilitates long-term potentiation (LTP) and restores impairments occurring with age. Interestingly, the newly discovered η-secretase cleavage product, An-α acts in the opposite direction, namely decreasing LTP. In this review we summarize recent findings with emphasis on the physiological role of the APP gene family and its proteolytic products on synaptic function and plasticity, especially during processes of hippocampal LTP. Therefore, we focus on literature that provide electrophysiological data by using different mutant mouse strains either lacking full-length or parts of the APP proteins or that utilized secretase inhibitors as well as secreted APP fragments.
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Affiliation(s)
- Susann Ludewig
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig Braunschweig, Germany
| | - Martin Korte
- Division of Cellular Neurobiology, Zoological Institute, TU BraunschweigBraunschweig, Germany; Helmholtz Centre for Infection Research, AG NINDBraunschweig, Germany
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Laßek M, Weingarten J, Wegner M, Neupärtl M, Array TN, Harde E, Beckert B, Golghalyani V, Ackermann J, Koch I, Müller UC, Karas M, Acker-Palmer A, Volknandt W. APP Deletion Accounts for Age-Dependent Changes in the Bioenergetic Metabolism and in Hyperphosphorylated CaMKII at Stimulated Hippocampal Presynaptic Active Zones. Front Synaptic Neurosci 2017; 9:1. [PMID: 28163681 PMCID: PMC5247443 DOI: 10.3389/fnsyn.2017.00001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 01/05/2017] [Indexed: 11/13/2022] Open
Abstract
Synaptic release sites are characterized by exocytosis-competent synaptic vesicles tightly anchored to the presynaptic active zone (PAZ) whose proteome orchestrates the fast signaling events involved in synaptic vesicle cycle and plasticity. Allocation of the amyloid precursor protein (APP) to the PAZ proteome implicated a functional impact of APP in neuronal communication. In this study, we combined state-of-the-art proteomics, electrophysiology and bioinformatics to address protein abundance and functional changes at the native hippocampal PAZ in young and old APP-KO mice. We evaluated if APP deletion has an impact on the metabolic activity of presynaptic mitochondria. Furthermore, we quantified differences in the phosphorylation status after long-term-potentiation (LTP) induction at the purified native PAZ. We observed an increase in the phosphorylation of the signaling enzyme calmodulin-dependent kinase II (CaMKII) only in old APP-KO mice. During aging APP deletion is accompanied by a severe decrease in metabolic activity and hyperphosphorylation of CaMKII. This attributes an essential functional role to APP at hippocampal PAZ and putative molecular mechanisms underlying the age-dependent impairments in learning and memory in APP-KO mice.
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Affiliation(s)
- Melanie Laßek
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Johann Wolfgang Goethe-Universität Frankfurt, Germany
| | - Jens Weingarten
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Johann Wolfgang Goethe-Universität Frankfurt, Germany
| | - Martin Wegner
- Molecular Bioinformatics, Johann Wolfgang Goethe-Universität Frankfurt, Germany
| | - Moritz Neupärtl
- Institute of Pharmaceutical Chemistry, Johann Wolfgang Goethe-Universität Frankfurt, Germany
| | | | - Eva Harde
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Johann Wolfgang Goethe-UniversitätFrankfurt, Germany; Max Planck Institute for Brain ResearchFrankfurt, Germany
| | - Benedikt Beckert
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Johann Wolfgang Goethe-Universität Frankfurt, Germany
| | - Vahid Golghalyani
- Institute of Pharmaceutical Chemistry, Johann Wolfgang Goethe-Universität Frankfurt, Germany
| | - Jörg Ackermann
- Molecular Bioinformatics, Johann Wolfgang Goethe-Universität Frankfurt, Germany
| | - Ina Koch
- Molecular Bioinformatics, Johann Wolfgang Goethe-Universität Frankfurt, Germany
| | - Ulrike C Müller
- Department of Pharmacy and Molecular Biotechnology, University Heidelberg Heidelberg, Germany
| | - Michael Karas
- Institute of Pharmaceutical Chemistry, Johann Wolfgang Goethe-Universität Frankfurt, Germany
| | - Amparo Acker-Palmer
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Johann Wolfgang Goethe-UniversitätFrankfurt, Germany; Max Planck Institute for Brain ResearchFrankfurt, Germany
| | - Walter Volknandt
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Johann Wolfgang Goethe-Universität Frankfurt, Germany
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Chen M, Wang J, Jiang J, Zheng X, Justice NJ, Wang K, Ran X, Li Y, Huo Q, Zhang J, Li H, Lu N, Wang Y, Zheng H, Long C, Yang L. APP modulates KCC2 expression and function in hippocampal GABAergic inhibition. eLife 2017; 6. [PMID: 28054918 PMCID: PMC5224924 DOI: 10.7554/elife.20142] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 12/16/2016] [Indexed: 12/14/2022] Open
Abstract
Amyloid precursor protein (APP) is enriched at the synapse, but its synaptic function is still poorly understood. We previously showed that GABAergic short-term plasticity is impaired in App knock-out (App-/-) animals, but the precise mechanism by which APP regulates GABAergic synaptic transmission has remained elusive. Using electrophysiological, biochemical, moleculobiological, and pharmacological analysis, here we show that APP can physically interact with KCC2, a neuron-specific K+-Cl- cotransporter that is essential for Cl- homeostasis and fast GABAergic inhibition. APP deficiency results in significant reductions in both total and membrane KCC2 levels, leading to a depolarizing shift in the GABA reversal potential (EGABA). Simultaneous measurement of presynaptic action potentials and inhibitory postsynaptic currents (IPSCs) in hippocampal neurons reveals impaired unitary IPSC amplitudes attributable to a reduction in α1 subunit levels of GABAAR. Importantly, restoration of normal KCC2 expression and function in App-/- mice rescues EGABA, GABAAR α1 levels and GABAAR mediated phasic inhibition. We show that APP functions to limit tyrosine-phosphorylation and ubiquitination and thus subsequent degradation of KCC2, providing a mechanism by which APP influences KCC2 abundance. Together, these experiments elucidate a novel molecular pathway in which APP regulates, via protein-protein interaction with KCC2, GABAAR mediated inhibition in the hippocampus. DOI:http://dx.doi.org/10.7554/eLife.20142.001 Alzheimer’s disease is the most common form of dementia. One of the hallmarks of the disease is the formation of sticky protein clumps called amyloid plaques in the brain. These plaques are formed from specific fragments of a protein called APP. The intact form of APP is essential for synapses (the junctions across which neurons transmit signals) to form and work correctly. The hippocampus is one of the first brain regions to be affected in Alzheimer’s disease and is important for forming memories and emotions. In the hippocampus, GABAA receptors at synapses normally tightly regulate synaptic signaling by reducing the ability of the receiving neuron to respond, but this inhibition is disrupted in Alzheimer’s disease. Studies suggest that APP can affect how GABAA receptors transmit signals, but it is not known how it does so. One possibility is that APP regulates a protein called KCC2 that helps to maintain the inhibitory effect of GABAA receptors. To investigate this, Chen et al. genetically modified mice to lack the gene that produces APP. These mice had a lower level of KCC2 in their hippocampus than normal mice, and their GABAA receptors were less able to inhibit synaptic signaling. Further experiments demonstrated that APP physically interacts with KCC2 and maintains normal levels of the protein by preventing it from being chemically modified and degraded. Chen et al. also showed that treating mice that lack APP with specific compounds can restore KCC2 activity and return the behavior of synaptic GABAA receptors to normal. Future studies in mice (and eventually people) that exhibit symptoms of Alzheimer's disease will help to determine whether KCC2 is important in the development of the disease. If so, modifying the levels of the KCC2 protein in the brain could potentially help to slow down memory loss in Alzheimer’s disease. DOI:http://dx.doi.org/10.7554/eLife.20142.002
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Affiliation(s)
- Ming Chen
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Jinzhao Wang
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Jinxiang Jiang
- School of Psychology and Center for Studies of Psychological Application, South China Normal University, Guangzhou, China.,Brain Science Institute, South China Normal University, Guangzhou, China
| | - Xingzhi Zheng
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Nicholas J Justice
- Institute of Molecular Medicine, University of Texas Health Sciences Center, Houston, United States
| | - Kun Wang
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xiangqian Ran
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Yi Li
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Qingwei Huo
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Jiajia Zhang
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Hongmei Li
- Huffington Center on Aging, Baylor College of Medicine, Houston, United States
| | - Nannan Lu
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Ying Wang
- School of Life Sciences, South China Normal University, Guangzhou, China
| | - Hui Zheng
- Huffington Center on Aging, Baylor College of Medicine, Houston, United States
| | - Cheng Long
- School of Life Sciences, South China Normal University, Guangzhou, China.,Brain Science Institute, South China Normal University, Guangzhou, China
| | - Li Yang
- School of Psychology and Center for Studies of Psychological Application, South China Normal University, Guangzhou, China.,Brain Science Institute, South China Normal University, Guangzhou, China.,Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou, China
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Mojabi FS, Fahimi A, Moghadam S, Moghadam S, Windy McNerneny M, Ponnusamy R, Kleschevnikov A, Mobley WC, Salehi A. GABAergic hyperinnervation of dentate granule cells in the Ts65Dn mouse model of down syndrome: Exploring the role of App. Hippocampus 2016; 26:1641-1654. [PMID: 27701794 DOI: 10.1002/hipo.22664] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2016] [Indexed: 12/20/2022]
Abstract
It has been suggested that increased GABAergic innervation in the hippocampus plays a significant role in cognitive dysfunction in Down syndrome (DS). Bolstering this notion, are studies linking hyper-innervation of the dentate gyrus (DG) by GABAergic terminals to failure in LTP induction in the Ts65Dn mouse model of DS. Here, we used extensive morphometrical methods to assess the status of GABAergic interneurons in the DG of young and old Ts65Dn mice and their 2N controls. We detected an age-dependent increase in GABAergic innervation of dentate granule cells (DGCs) in Ts65Dn mice. The primary source of GABAergic terminals to DGCs somata is basket cells (BCs). For this reason, we assessed the status of these cells and found a significant increase in the number of BCs in Ts65Dn mice compared with controls. Then we aimed to identify the gene/s whose overexpression could be linked to increased number of BCs in Ts65Dn and found that deleting the third copy of App gene in Ts65Dn mice led to normalization of the number of BCs in these mice. Our data suggest that App overexpression plays a major role in the pathophysiology of GABAergic hyperinnervation of the DG in Ts65Dn mice. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Fatemeh S Mojabi
- VA Palo Alto Health Care System, Palo Alto, California.,Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, California
| | - Atoossa Fahimi
- VA Palo Alto Health Care System, Palo Alto, California.,Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, California
| | | | | | - M Windy McNerneny
- VA Palo Alto Health Care System, Palo Alto, California.,Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, California
| | | | | | - William C Mobley
- Department of Neurosciences, University of California, San Diego, California
| | - Ahmad Salehi
- VA Palo Alto Health Care System, Palo Alto, California.,Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, California
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Expression of Phenotypic Astrocyte Marker Is Increased in a Transgenic Mouse Model of Alzheimer's Disease versus Age-Matched Controls: A Presymptomatic Stage Study. Int J Alzheimers Dis 2016; 2016:5696241. [PMID: 27672476 PMCID: PMC5031839 DOI: 10.1155/2016/5696241] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 08/03/2016] [Accepted: 08/14/2016] [Indexed: 12/29/2022] Open
Abstract
Recent mouse studies of the presymptomatic stage of Alzheimer's disease (AD) have suggested that proinflammatory changes, such as glial activation and cytokine induction, may occur already at this early stage through unknown mechanisms. Because TNFα contributes to increased Aβ production from the Aβ precursor protein (APP), we assessed a putative correlation between APP/Aβ and TNFα during the presymptomatic stage as well as early astrocyte activation in the hippocampus of 3-month-old APPswe/PS1dE9 mice. While Western blots revealed significant APP expression, Aβ was not detectable by Western blot or ELISA attesting that 3-month-old, APPswe/PS1dE9 mice are at a presymptomatic stage of AD-like pathology. Western blots were also used to show increased GFAP expression in transgenic mice that positively correlated with both TNFα and APP, which were also mutually correlated. Subregional immunohistochemical quantification of phenotypic (GFAP) and functional (TSPO) markers of astrocyte activation indicated a selective and significant increase in GFAP-immunoreactive (IR) cells in the dentate gyrus of APPswe/PS1dE9 mice. Our data suggest that subtle morphological and phenotypic alterations, compatible with the engagement of astrocyte along the activation pathway, occur in the hippocampus already at the presymptomatic stage of AD.
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