1
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Almeida VN. Somatostatin and the pathophysiology of Alzheimer's disease. Ageing Res Rev 2024; 96:102270. [PMID: 38484981 DOI: 10.1016/j.arr.2024.102270] [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] [Received: 07/18/2023] [Revised: 03/09/2024] [Accepted: 03/09/2024] [Indexed: 03/28/2024]
Abstract
Among the central features of Alzheimer's disease (AD) progression are altered levels of the neuropeptide somatostatin (SST), and the colocalisation of SST-positive interneurons (SST-INs) with amyloid-β plaques, leading to cell death. In this theoretical review, I propose a molecular model for the pathogenesis of AD based on SST-IN hypofunction and hyperactivity. Namely, hypofunctional and hyperactive SST-INs struggle to control hyperactivity in medial regions in early stages, leading to axonal Aβ production through excessive presynaptic GABAB inhibition, GABAB1a/APP complex downregulation and internalisation. Concomitantly, excessive SST-14 release accumulates near SST-INs in the form of amyloids, which bind to Aβ to form toxic mixed oligomers. This leads to differential SST-IN death through excitotoxicity, further disinhibition, SST deficits, and increased Aβ release, fibrillation and plaque formation. Aβ plaques, hyperactive networks and SST-IN distributions thereby tightly overlap in the brain. Conversely, chronic stimulation of postsynaptic SST2/4 on gulutamatergic neurons by hyperactive SST-INs promotes intense Mitogen-Activated Protein Kinase (MAPK) p38 activity, leading to somatodendritic p-tau staining and apoptosis/neurodegeneration - in agreement with a near complete overlap between p38 and neurofibrillary tangles. This model is suitable to explain some of the principal risk factors and markers of AD progression, including mitochondrial dysfunction, APOE4 genotype, sex-dependent vulnerability, overactive glial cells, dystrophic neurites, synaptic/spine losses, inter alia. Finally, the model can also shed light on qualitative aspects of AD neuropsychology, especially within the domains of spatial and declarative (episodic, semantic) memory, under an overlying pattern of contextual indiscrimination, ensemble instability, interference and generalisation.
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Affiliation(s)
- Victor N Almeida
- Institute of Psychiatry, Faculty of Medicine, University of São Paulo (USP), Brazil; Faculty of Languages, Federal University of Minas Gerais (UFMG), Brazil.
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2
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Ji X, Peng X, Tang H, Pan H, Wang W, Wu J, Chen J, Wei N. Alzheimer's disease phenotype based upon the carrier status of the apolipoprotein E ɛ4 allele. Brain Pathol 2024; 34:e13208. [PMID: 37646624 PMCID: PMC10711266 DOI: 10.1111/bpa.13208] [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: 12/06/2022] [Accepted: 08/05/2023] [Indexed: 09/01/2023] Open
Abstract
The apolipoprotein E ɛ4 allele (APOE4) is universally acknowledged as the most potent genetic risk factor for Alzheimer's disease (AD). APOE4 promotes the initiation and progression of AD. Although the underlying mechanisms are unclearly understood, differences in lipid-bound affinity among the three APOE isoforms may constitute the basis. The protein APOE4 isoform has a high affinity with triglycerides and cholesterol. A distinction in lipid metabolism extensively impacts neurons, microglia, and astrocytes. APOE4 carriers exhibit phenotypic differences from non-carriers in clinical examinations and respond differently to multiple treatments. Therefore, we hypothesized that phenotypic classification of AD patients according to the status of APOE4 carrier will help specify research and promote its use in diagnosing and treating AD. Recent reviews have mainly evaluated the differences between APOE4 allele carriers and non-carriers from gene to protein structures, clinical features, neuroimaging, pathology, the neural network, and the response to various treatments, and have provided the feasibility of phenotypic group classification based on APOE4 carrier status. This review will facilitate the application of APOE phenomics concept in clinical practice and promote further medical research on AD.
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Affiliation(s)
- Xiao‐Yu Ji
- Department of NeurosurgeryThe First Affiliated Hospital of Shantou University Medical CollegeGuangdongChina
- Brain Function and Disease LaboratoryShantou University Medical CollegeGuangdongChina
| | - Xin‐Yuan Peng
- Department of NeurosurgeryThe First Affiliated Hospital of Shantou University Medical CollegeGuangdongChina
| | - Hai‐Liang Tang
- Fudan University Huashan Hospital, Department of Neurosurgery, State Key Laboratory for Medical NeurobiologyInstitutes of Brain Science, Shanghai Medical College‐Fudan UniversityShanghaiChina
| | - Hui Pan
- Shantou Longhu People's HospitalShantouGuangdongChina
| | - Wei‐Tang Wang
- Department of NeurosurgeryThe First Affiliated Hospital of Shantou University Medical CollegeGuangdongChina
| | - Jie Wu
- Department of NeurosurgeryThe First Affiliated Hospital of Shantou University Medical CollegeGuangdongChina
- Brain Function and Disease LaboratoryShantou University Medical CollegeGuangdongChina
| | - Jian Chen
- Department of NeurosurgeryThe First Affiliated Hospital of Shantou University Medical CollegeGuangdongChina
| | - Nai‐Li Wei
- Department of NeurosurgeryThe First Affiliated Hospital of Shantou University Medical CollegeGuangdongChina
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3
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Tomás AM, Bento-Torres NVO, Jardim NYV, Moraes PM, da Costa VO, Modesto AC, Khayat AS, Bento-Torres J, Picanço-Diniz CW. Risk Polymorphisms of FNDC5, BDNF, and NTRK2 and Poor Education Interact and Aggravate Age-Related Cognitive Decline. Int J Mol Sci 2023; 24:17210. [PMID: 38139046 PMCID: PMC10743741 DOI: 10.3390/ijms242417210] [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: 10/19/2023] [Revised: 11/07/2023] [Accepted: 11/17/2023] [Indexed: 12/24/2023] Open
Abstract
Cognitive abilities tend to decline with aging, with variation between individuals, and many studies seek to identify genetic biomarkers that more accurately anticipate risks related to pathological aging. We investigated the influence of BDNF, NTRK2, and FNDC5 single nucleotide polymorphisms (SNPs) on the cognitive performance of young and older adults with contrasting educational backgrounds. We addressed three questions: (1) Is education associated with reduced age-related cognitive decline? (2) Does the presence of SNPs explain the variation in cognitive performance observed late in life? (3) Is education differentially associated with cognition based on the presence of BDNF, NTRK2, or FNDC5 polymorphisms? We measured the cognitive functions of young and older participants, with lower and higher education, using specific and sensitive tests of the Cambridge Automated Neuropsychological Test Assessment Battery. A three-way ANOVA revealed that SNPs were associated with differential performances in executive functions, episodic memory, sustained attention, mental and motor response speed, and visual recognition memory and that higher educational levels improved the affected cognitive functions. The results revealed that distinct SNPs affect cognition late in life differentially, suggesting their utility as potential biomarkers and emphasizing the importance of cognitive stimulation that advanced education early in life provides.
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Affiliation(s)
- Alessandra Mendonça Tomás
- Neurodegeneration and Infection Research Laboratory, Institute of Biological Science, João de Barros Barreto University Hospital, Federal University of Pará, Belém 66073-000, Brazil; (A.M.T.); (N.Y.V.J.); (P.M.M.); (V.O.d.C.); (J.B.-T.); (C.W.P.-D.)
- Department of Physical Education, Federal University of Pará Application School, Belém 66095-780, Brazil
| | - Natáli Valim Oliver Bento-Torres
- Neurodegeneration and Infection Research Laboratory, Institute of Biological Science, João de Barros Barreto University Hospital, Federal University of Pará, Belém 66073-000, Brazil; (A.M.T.); (N.Y.V.J.); (P.M.M.); (V.O.d.C.); (J.B.-T.); (C.W.P.-D.)
- Graduate Program in Human Movement Sciences, Federal University of Pará, Belém 66095-780, Brazil
| | - Naina Yuki Vieira Jardim
- Neurodegeneration and Infection Research Laboratory, Institute of Biological Science, João de Barros Barreto University Hospital, Federal University of Pará, Belém 66073-000, Brazil; (A.M.T.); (N.Y.V.J.); (P.M.M.); (V.O.d.C.); (J.B.-T.); (C.W.P.-D.)
- Graduate Program in Neuroscience and Cell Biology, Federal University of Pará, Belém 66050-160, Brazil
| | - Patrícia Martins Moraes
- Neurodegeneration and Infection Research Laboratory, Institute of Biological Science, João de Barros Barreto University Hospital, Federal University of Pará, Belém 66073-000, Brazil; (A.M.T.); (N.Y.V.J.); (P.M.M.); (V.O.d.C.); (J.B.-T.); (C.W.P.-D.)
- Graduate Program in Human Movement Sciences, Federal University of Pará, Belém 66095-780, Brazil
| | - Victor Oliveira da Costa
- Neurodegeneration and Infection Research Laboratory, Institute of Biological Science, João de Barros Barreto University Hospital, Federal University of Pará, Belém 66073-000, Brazil; (A.M.T.); (N.Y.V.J.); (P.M.M.); (V.O.d.C.); (J.B.-T.); (C.W.P.-D.)
- Graduate Program in Neuroscience and Cell Biology, Federal University of Pará, Belém 66050-160, Brazil
| | - Antônio Conde Modesto
- Oncology Research Center (NPO), Graduate Program in Oncology and Medical Sciences, Federal University of Pará, Belém 66073-000, Brazil; (A.C.M.); (A.S.K.)
| | - André Salim Khayat
- Oncology Research Center (NPO), Graduate Program in Oncology and Medical Sciences, Federal University of Pará, Belém 66073-000, Brazil; (A.C.M.); (A.S.K.)
| | - João Bento-Torres
- Neurodegeneration and Infection Research Laboratory, Institute of Biological Science, João de Barros Barreto University Hospital, Federal University of Pará, Belém 66073-000, Brazil; (A.M.T.); (N.Y.V.J.); (P.M.M.); (V.O.d.C.); (J.B.-T.); (C.W.P.-D.)
- Graduate Program in Human Movement Sciences, Federal University of Pará, Belém 66095-780, Brazil
| | - Cristovam Wanderley Picanço-Diniz
- Neurodegeneration and Infection Research Laboratory, Institute of Biological Science, João de Barros Barreto University Hospital, Federal University of Pará, Belém 66073-000, Brazil; (A.M.T.); (N.Y.V.J.); (P.M.M.); (V.O.d.C.); (J.B.-T.); (C.W.P.-D.)
- Graduate Program in Neuroscience and Cell Biology, Federal University of Pará, Belém 66050-160, Brazil
- Oncology Research Center (NPO), Graduate Program in Oncology and Medical Sciences, Federal University of Pará, Belém 66073-000, Brazil; (A.C.M.); (A.S.K.)
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4
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Strong CE, Zhang J, Carrasco M, Kundu S, Boutin M, Vishwasrao HD, Liu J, Medina A, Chen YC, Wilson K, Lee EM, Ferrer M. Functional brain region-specific neural spheroids for modeling neurological diseases and therapeutics screening. Commun Biol 2023; 6:1211. [PMID: 38017066 PMCID: PMC10684574 DOI: 10.1038/s42003-023-05582-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 11/14/2023] [Indexed: 11/30/2023] Open
Abstract
3D spheroids have emerged as powerful drug discovery tools given their high-throughput screening (HTS) compatibility. Here, we describe a method for generating functional neural spheroids by cell-aggregation of differentiated human induced pluripotent stem cell (hiPSC)-derived neurons and astrocytes at cell type compositions mimicking specific regions of the human brain. Recordings of intracellular calcium oscillations were used as functional assays, and the utility of this spheroids system was shown through disease modeling, drug testing, and formation of assembloids to model neurocircuitry. As a proof of concept, we generated spheroids incorporating neurons with Alzheimer's disease-associated alleles, as well as opioid use disorder modeling spheroids induced by chronic treatment of a mu-opioid receptor agonist. We reversed baseline functional deficits in each pilot disease model with clinically approved treatments and showed that assembloid activity can be chemogenetically manipulated. Here, we lay the groundwork for brain region-specific neural spheroids as a robust functional assay platform for HTS studies.
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Affiliation(s)
- Caroline E Strong
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Jiajing Zhang
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Martin Carrasco
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Srikanya Kundu
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Molly Boutin
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Harshad D Vishwasrao
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jiamin Liu
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Angelica Medina
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Yu-Chi Chen
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Kelli Wilson
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Emily M Lee
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA.
| | - Marc Ferrer
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA.
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5
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Tang Y, Yan Y, Mao J, Ni J, Qing H. The hippocampus associated GABAergic neural network impairment in early-stage of Alzheimer's disease. Ageing Res Rev 2023; 86:101865. [PMID: 36716975 DOI: 10.1016/j.arr.2023.101865] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/13/2023] [Accepted: 01/25/2023] [Indexed: 01/29/2023]
Abstract
Alzheimer's disease (AD) is the commonest neurodegenerative disease with slow progression. Pieces of evidence suggest that the GABAergic system is impaired in the early stage of AD, leading to hippocampal neuron over-activity and further leading to memory and cognitive impairment in patients with AD. However, the precise impairment mechanism of the GABAergic system on the pathogenesis of AD is still unclear. The impairment of neural networks associated with the GABAergic system is tightly associated with AD. Therefore, we describe the roles played by hippocampus-related GABAergic circuits and their impairments in AD neuropathology. In addition, we give our understand on the process from GABAergic circuit impairment to cognitive and memory impairment, since recent studies on astrocyte in AD plays an important role behind cognition dysfunction caused by GABAergic circuit impairment, which helps better understand the GABAergic system and could open up innovative AD therapy.
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Affiliation(s)
- Yuanhong Tang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Yan Yan
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Jian Mao
- Zhengzhou Tobacco Institute of China National Tobacco Company, Zhengzhou 450001, China
| | - Junjun Ni
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing 100081, China.
| | - Hong Qing
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing 100081, China; Department of Biology, Shenzhen MSU-BIT University, Shenzhen 518172, China.
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6
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Steele OG, Stuart AC, Minkley L, Shaw K, Bonnar O, Anderle S, Penn AC, Rusted J, Serpell L, Hall C, King S. A multi-hit hypothesis for an APOE4-dependent pathophysiological state. Eur J Neurosci 2022; 56:5476-5515. [PMID: 35510513 PMCID: PMC9796338 DOI: 10.1111/ejn.15685] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 03/31/2022] [Accepted: 04/25/2022] [Indexed: 01/01/2023]
Abstract
The APOE gene encoding the Apolipoprotein E protein is the single most significant genetic risk factor for late-onset Alzheimer's disease. The APOE4 genotype confers a significantly increased risk relative to the other two common genotypes APOE3 and APOE2. Intriguingly, APOE4 has been associated with neuropathological and cognitive deficits in the absence of Alzheimer's disease-related amyloid or tau pathology. Here, we review the extensive literature surrounding the impact of APOE genotype on central nervous system dysfunction, focussing on preclinical model systems and comparison of APOE3 and APOE4, given the low global prevalence of APOE2. A multi-hit hypothesis is proposed to explain how APOE4 shifts cerebral physiology towards pathophysiology through interconnected hits. These hits include the following: neurodegeneration, neurovascular dysfunction, neuroinflammation, oxidative stress, endosomal trafficking impairments, lipid and cellular metabolism disruption, impaired calcium homeostasis and altered transcriptional regulation. The hits, individually and in combination, leave the APOE4 brain in a vulnerable state where further cumulative insults will exacerbate degeneration and lead to cognitive deficits in the absence of Alzheimer's disease pathology and also a state in which such pathology may more easily take hold. We conclude that current evidence supports an APOE4 multi-hit hypothesis, which contributes to an APOE4 pathophysiological state. We highlight key areas where further study is required to elucidate the complex interplay between these individual mechanisms and downstream consequences, helping to frame the current landscape of existing APOE-centric literature.
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Affiliation(s)
| | | | - Lucy Minkley
- School of Life SciencesUniversity of SussexBrightonUK
| | - Kira Shaw
- School of Life SciencesUniversity of SussexBrightonUK
| | - Orla Bonnar
- School of Life SciencesUniversity of SussexBrightonUK
| | | | | | | | | | | | - Sarah King
- School of PsychologyUniversity of SussexBrightonUK
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7
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Capsoni S, Arisi I, Malerba F, D’Onofrio M, Cattaneo A, Cherubini E. Targeting the Cation-Chloride Co-Transporter NKCC1 to Re-Establish GABAergic Inhibition and an Appropriate Excitatory/Inhibitory Balance in Selective Neuronal Circuits: A Novel Approach for the Treatment of Alzheimer's Disease. Brain Sci 2022; 12:brainsci12060783. [PMID: 35741668 PMCID: PMC9221351 DOI: 10.3390/brainsci12060783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 01/27/2023] Open
Abstract
GABA, the main inhibitory neurotransmitter in the adult brain, depolarizes and excites immature neurons because of an initially higher intracellular chloride concentration [Cl-]i due to the delayed expression of the chloride exporter KCC2 at birth. Depolarization-induced calcium rise via NMDA receptors and voltage-dependent calcium channels is instrumental in shaping neuronal circuits and in controlling the excitatory (E)/inhibitory (I) balance in selective brain areas. An E/I imbalance accounts for cognitive impairment observed in several neuropsychiatric disorders. The aim of this review is to summarize recent data on the mechanisms by which alterations of GABAergic signaling alter the E/I balance in cortical and hippocampal neurons in Alzheimer's disease (AD) and the role of cation-chloride co-transporters in this process. In particular, we discuss the NGF and AD relationship and how mice engineered to express recombinant neutralizing anti-NGF antibodies (AD11 mice), which develop a neurodegenerative pathology reminiscent of that observed in AD patients, exhibit a depolarizing action of GABA due to KCC2 impairment. Treating AD and other forms of dementia with bumetanide, a selective KCC2 antagonist, contributes to re-establishing a proper E/I balance in selective brain areas, leading to amelioration of AD symptoms and the slowing down of disease progression.
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Affiliation(s)
- Simona Capsoni
- Bio@SNS Laboratory of Biology, Scuola Normale Superiore, 56126 Pisa, Italy;
- Section of Physiology, Department of Neuroscience and Rehabilitation, University of Ferrara, 44121 Ferrara, Italy
| | - Ivan Arisi
- Fondazione European Brain Research Institute (EBRI) Rita Levi-Montalcini, 00161 Rome, Italy; (I.A.); (F.M.); (M.D.)
| | - Francesca Malerba
- Fondazione European Brain Research Institute (EBRI) Rita Levi-Montalcini, 00161 Rome, Italy; (I.A.); (F.M.); (M.D.)
| | - Mara D’Onofrio
- Fondazione European Brain Research Institute (EBRI) Rita Levi-Montalcini, 00161 Rome, Italy; (I.A.); (F.M.); (M.D.)
| | - Antonino Cattaneo
- Bio@SNS Laboratory of Biology, Scuola Normale Superiore, 56126 Pisa, Italy;
- Fondazione European Brain Research Institute (EBRI) Rita Levi-Montalcini, 00161 Rome, Italy; (I.A.); (F.M.); (M.D.)
- Correspondence: (A.C.); (E.C.); Tel.: +39-050-509320 (A.C.); +39-06-49255255 (E.C.)
| | - Enrico Cherubini
- Fondazione European Brain Research Institute (EBRI) Rita Levi-Montalcini, 00161 Rome, Italy; (I.A.); (F.M.); (M.D.)
- Correspondence: (A.C.); (E.C.); Tel.: +39-050-509320 (A.C.); +39-06-49255255 (E.C.)
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8
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Ghit A, Assal D, Al-Shami AS, Hussein DEE. GABA A receptors: structure, function, pharmacology, and related disorders. J Genet Eng Biotechnol 2021; 19:123. [PMID: 34417930 PMCID: PMC8380214 DOI: 10.1186/s43141-021-00224-0] [Citation(s) in RCA: 95] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/08/2021] [Indexed: 02/03/2023]
Abstract
Background γ-Aminobutyric acid sub-type A receptors (GABAARs) are the most prominent inhibitory neurotransmitter receptors in the CNS. They are a family of ligand-gated ion channel with significant physiological and therapeutic implications. Main body GABAARs are heteropentamers formed from a selection of 19 subunits: six α (alpha1-6), three β (beta1-3), three γ (gamma1-3), three ρ (rho1-3), and one each of the δ (delta), ε (epsilon), π (pi), and θ (theta) which result in the production of a considerable number of receptor isoforms. Each isoform exhibits distinct pharmacological and physiological properties. However, the majority of GABAARs are composed of two α subunits, two β subunits, and one γ subunit arranged as γ2β2α1β2α1 counterclockwise around the center. The mature receptor has a central chloride ion channel gated by GABA neurotransmitter and modulated by a variety of different drugs. Changes in GABA synthesis or release may have a significant effect on normal brain function. Furthermore, The molecular interactions and pharmacological effects caused by drugs are extremely complex. This is due to the structural heterogeneity of the receptors, and the existence of multiple allosteric binding sites as well as a wide range of ligands that can bind to them. Notably, dysfunction of the GABAergic system contributes to the development of several diseases. Therefore, understanding the relationship between GABAA receptor deficits and CNS disorders thus has a significant impact on the discovery of disease pathogenesis and drug development. Conclusion To date, few reviews have discussed GABAA receptors in detail. Accordingly, this review aims to summarize the current understanding of the structural, physiological, and pharmacological properties of GABAARs, as well as shedding light on the most common associated disorders.
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Affiliation(s)
- Amr Ghit
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy. .,Department of Biotechnology, Institute of Graduate Studies and Research (IGSR), Alexandria University, Alexandria, Egypt.
| | - Dina Assal
- Department of Biotechnology, American University in Cairo (AUC), Cairo, Egypt
| | - Ahmed S Al-Shami
- Department of Biotechnology, Institute of Graduate Studies and Research (IGSR), Alexandria University, Alexandria, Egypt.,Department of Zoology, Faculty of Science, Alexandria University, Alexandria, Egypt
| | - Diaa Eldin E Hussein
- Animal Health Research Institute (AHRI), Agricultural Research Center (ARC), Port of Alexandria, Alexandria, Egypt
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9
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Higgins-Chen AT, Thrush KL, Levine ME. Aging biomarkers and the brain. Semin Cell Dev Biol 2021; 116:180-193. [PMID: 33509689 PMCID: PMC8292153 DOI: 10.1016/j.semcdb.2021.01.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 12/15/2022]
Abstract
Quantifying biological aging is critical for understanding why aging is the primary driver of morbidity and mortality and for assessing novel therapies to counter pathological aging. In the past decade, many biomarkers relevant to brain aging have been developed using various data types and modeling techniques. Aging involves numerous interconnected processes, and thus many complementary biomarkers are needed, each capturing a different slice of aging biology. Here we present a hierarchical framework highlighting how these biomarkers are related to each other and the underlying biological processes. We review those measures most studied in the context of brain aging: epigenetic clocks, proteomic clocks, and neuroimaging age predictors. Many studies have linked these biomarkers to cognition, mental health, brain structure, and pathology during aging. We also delve into the challenges and complexities in interpreting these biomarkers and suggest areas for further innovation. Ultimately, a robust mechanistic understanding of these biomarkers will be needed to effectively intervene in the aging process to prevent and treat age-related disease.
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Affiliation(s)
- Albert T Higgins-Chen
- Department of Psychiatry, Yale University School of Medicine, 300 George St, Suite 901, New Haven, CT 06511, USA.
| | - Kyra L Thrush
- Program in Computational Biology and Bioinformatics, Yale University, 300 George St, Suite 501, New Haven, CT 06511, USA.
| | - Morgan E Levine
- Department of Pathology, Yale University School of Medicine, 310 Cedar Street, Suite LH 315A, New Haven, CT 06520, USA.
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10
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Lu MH, Zhao XY, Xu DE, Chen JB, Ji WL, Huang ZP, Pan TT, Xue LL, Wang F, Li QF, Zhang Y, Wang TH, Yanagawa Y, Liu CF, Xu RX, Xia YY, Li S, Ma QH. Transplantation of GABAergic Interneuron Progenitor Attenuates Cognitive Deficits of Alzheimer's Disease Model Mice. J Alzheimers Dis 2021; 75:245-260. [PMID: 32280096 DOI: 10.3233/jad-200010] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Excitatory (E) and inhibitory (I) balance of neural network activity is essential for normal brain function and of particular importance to memory. Disturbance of E/I balance contributes to various neurological disorders. The appearance of neural hyperexcitability in Alzheimer's disease (AD) is even suggested as one of predictors of accelerated cognitive decline. In this study, we found that GAD67+, Parvalbumin+, Calretinin+, and Neuropeptide Y+ interneurons were progressively lost in the brain of APP/PS1 mice. Transplanted embryonic medial ganglionic eminence derived interneuron progenitors (IPs) survived, migrated, and differentiated into GABAergic interneuron subtypes successfully at 2 months after transplantation. Transplantation of IPs hippocampally rescued impaired synaptic plasticity and cognitive deficits of APP/PS1 transgenic mice, concomitant with a suppression of neural hyperexcitability, whereas transplantation of IPs failed to attenuate amyloid-β accumulation, neuroinflammation, and synaptic loss of APP/PS1 transgenic mice. These observations indicate that transplantation of IPs improves learning and memory of APP/PS1 transgenic mice via suppressing neural hyperexcitability. This study highlights a causal contribution of GABAergic dysfunction to AD pathogenesis and the potentiality of IP transplantation in AD therapy.
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Affiliation(s)
- Mei-Hong Lu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, China.,Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, the Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Xiu-Yun Zhao
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, China.,Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, the Second Affiliated Hospital of Soochow University, Suzhou, China
| | - De-En Xu
- Department of Neurology, the Second People's Hospital of Wuxi, Wuxi, Jiangsu Province, China
| | - Ji-Bo Chen
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, China.,Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, the Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Wen-Li Ji
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, China.,Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, the Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Ze-Ping Huang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, China.,Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, the Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Ting-Ting Pan
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, China.,Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, the Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Lu-Lu Xue
- Institute of Neuroscience, Kunming Medical University, Kunming, China
| | - Fen Wang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, China.,Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, the Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Qi-Fa Li
- Department of Physiology, National-Local Joint Engineering Research Center for Drug-Research and Development (R & D) of Neurodegenerative Diseases, Liaoning Provincial Key Laboratory of Cerebral Diseases, Dalian Medical University, Dalian, Liaoning, China
| | - Yue Zhang
- Department of Physiology, National-Local Joint Engineering Research Center for Drug-Research and Development (R & D) of Neurodegenerative Diseases, Liaoning Provincial Key Laboratory of Cerebral Diseases, Dalian Medical University, Dalian, Liaoning, China
| | - Ting-Hua Wang
- Institute of Neuroscience, Kunming Medical University, Kunming, China
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Chun-Feng Liu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, China.,Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, the Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Ru-Xiang Xu
- Department of Neurosurgery, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Yi-Yuan Xia
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, China.,Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, the Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Shao Li
- Department of Physiology, National-Local Joint Engineering Research Center for Drug-Research and Development (R & D) of Neurodegenerative Diseases, Liaoning Provincial Key Laboratory of Cerebral Diseases, Dalian Medical University, Dalian, Liaoning, China
| | - Quan-Hong Ma
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, China.,Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, the Second Affiliated Hospital of Soochow University, Suzhou, China
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11
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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: 89] [Impact Index Per Article: 22.3] [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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12
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Bi D, Wen L, Wu Z, Shen Y. GABAergic dysfunction in excitatory and inhibitory (E/I) imbalance drives the pathogenesis of Alzheimer's disease. Alzheimers Dement 2020; 16:1312-1329. [PMID: 32543726 DOI: 10.1002/alz.12088] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 01/28/2020] [Accepted: 02/10/2020] [Indexed: 12/28/2022]
Abstract
OBJECTIVE To propose a new hypothesis that GABAergic dysfunction in excitatory and inhibitory (E/I) imbalance drives the pathogenesis of Alzheimer's disease (AD). BACKGROUND Synaptic dysfunction and E/I imbalance emerge decades before the appearance of cognitive decline in AD patients, which contribute to neurodegeneration. Initially, E/I imbalance was thought to occur first, due to dysfunction of the glutamatergic and cholinergic systems. However, new evidence has demonstrated that the GABAergic system, the counterpart of E/I balance and the major inhibitory neurotransmitter system in the central nervous system, is altered enormously and that this contributes to E/I imbalance and further AD pathogenesis. NEW HYPOTHESIS Alterations to the GABAergic system, induced by multiple AD pathogenic or risk factors, contribute to E/I imbalance and AD pathogenesis. MAJOR CHALLENGES FOR THE HYPOTHESIS This GABAergic hypothesis accounts for many critical questions and common challenges confronting a new hypothesis of AD pathogenesis. More specifically, it explains why amyloid beta (Aβ), β-secretase (BACE1), apolipoprotein E4 gene (APOE ε4), hyperactive glia cells, contributes to AD pathogenesis and why age and sex are the risk factors of AD. GABAergic dysfunction promotes the spread of Aβ pathology throughout the AD brain and associated cognitive impairments, and the induction of dysfunction induced by these varied risk factors shares this common neurobiology leading to E/I imbalance. In turn, some of these factors exacerbate GABAergic dysfunction and E/I imbalance. Moreover, the GABAergic system modulates various brain functions and thus, the GABAergic hypothesis accounts for nonamnestic manifestations. Furthermore, corrections of E/I balance through manipulation of GABAergic functions have shown positive outcomes in preclinical and clinical studies, suggesting the potential of the GABAergic system as a therapeutic target in AD. LINKAGE TO OTHER MAJOR THEORIES Dysfunction of the GABAergic system is induced by multiple critical signaling pathways, which include the existing major theories of AD pathogenesis, such as the Aβ and neuroinflammation hypotheses. In a new perspective, this GABAergic hypothesis accounts for the E/I imbalance and related excitotoxicity, which contribute to cognitive decline and AD pathogenesis. Therefore, the GABAergic system could be a key target to restore, at least partially, the E/I balance and cognitive function in AD patients.
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Affiliation(s)
- Danlei Bi
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Institute on Aging and Brain Disorders, University of Sciences and Technology of China, Hefei, China.,Neurodegenerative Disease Research Center, University of Science and Technology of China, Hefei, China.,Hefei National Laboratory for Physical Sciences at the Microscale, Neurodegenerative Disorder Research Center, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Lang Wen
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Institute on Aging and Brain Disorders, University of Sciences and Technology of China, Hefei, China.,Neurodegenerative Disease Research Center, University of Science and Technology of China, Hefei, China.,Hefei National Laboratory for Physical Sciences at the Microscale, Neurodegenerative Disorder Research Center, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Zujun Wu
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Institute on Aging and Brain Disorders, University of Sciences and Technology of China, Hefei, China.,Neurodegenerative Disease Research Center, University of Science and Technology of China, Hefei, China.,Hefei National Laboratory for Physical Sciences at the Microscale, Neurodegenerative Disorder Research Center, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yong Shen
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Institute on Aging and Brain Disorders, University of Sciences and Technology of China, Hefei, China.,Neurodegenerative Disease Research Center, University of Science and Technology of China, Hefei, China.,Hefei National Laboratory for Physical Sciences at the Microscale, Neurodegenerative Disorder Research Center, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
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13
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Dal Prà I, Armato U, Chiarini A. Family C G-Protein-Coupled Receptors in Alzheimer's Disease and Therapeutic Implications. Front Pharmacol 2019; 10:1282. [PMID: 31719824 PMCID: PMC6826475 DOI: 10.3389/fphar.2019.01282] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 10/07/2019] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD), particularly its sporadic or late-onset form (SAD/LOAD), is the most prevalent (96–98% of cases) neurodegenerative dementia in aged people. AD’s neuropathology hallmarks are intrabrain accumulation of amyloid-β peptides (Aβs) and of hyperphosphorylated Tau (p-Tau) proteins, diffuse neuroinflammation, and progressive death of neurons and oligodendrocytes. Mounting evidences suggest that family C G-protein-coupled receptors (GPCRs), which include γ-aminobutyric acid B receptors (GABABRs), metabotropic glutamate receptors (mGluR1-8), and the calcium-sensing receptor (CaSR), are involved in many neurotransmitter systems that dysfunction in AD. This review updates the available knowledge about the roles of GPCRs, particularly but not exclusively those expressed by brain astrocytes, in SAD/LOAD onset and progression, taking stock of their respective mechanisms of action and of their potential as anti-AD therapeutic targets. In particular, GABABRs prevent Aβs synthesis and neuronal hyperexcitability and group I mGluRs play important pathogenetic roles in transgenic AD-model animals. Moreover, the specific binding of Aβs to the CaSRs of human cortical astrocytes and neurons cultured in vitro engenders a pathological signaling that crucially promotes the surplus synthesis and release of Aβs and hyperphosphorylated Tau proteins, and also of nitric oxide, vascular endothelial growth factor-A, and proinflammatory agents. Concurrently, Aβs•CaSR signaling hinders the release of soluble (s)APP-α peptide, a neurotrophic agent and GABABR1a agonist. Altogether these effects progressively kill human cortical neurons in vitro and likely also in vivo. Several CaSR’s negative allosteric modulators suppress all the noxious effects elicited by Aβs•CaSR signaling in human cortical astrocytes and neurons thus safeguarding neurons’ viability in vitro and raising hopes about their potential therapeutic benefits in AD patients. Further basic and clinical investigations on these hot topics are needed taking always heed that activation of the several brain family C GPCRs may elicit divergent upshots according to the models studied.
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Affiliation(s)
- Ilaria Dal Prà
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
| | - Ubaldo Armato
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
| | - Anna Chiarini
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
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14
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Sanchez-Mejias E, Nuñez-Diaz C, Sanchez-Varo R, Gomez-Arboledas A, Garcia-Leon JA, Fernandez-Valenzuela JJ, Mejias-Ortega M, Trujillo-Estrada L, Baglietto-Vargas D, Moreno-Gonzalez I, Davila JC, Vitorica J, Gutierrez A. Distinct disease-sensitive GABAergic neurons in the perirhinal cortex of Alzheimer's mice and patients. Brain Pathol 2019; 30:345-363. [PMID: 31491047 PMCID: PMC7064898 DOI: 10.1111/bpa.12785] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 09/02/2019] [Indexed: 12/29/2022] Open
Abstract
Neuronal loss is the best neuropathological substrate that correlates with cortical atrophy and dementia in Alzheimer's disease (AD). Defective GABAergic neuronal functions may lead to cortical network hyperactivity and aberrant neuronal oscillations and in consequence, generate a detrimental alteration in memory processes. In this study, using immunohistochemical and stereological approaches, we report that the two major and non-overlapping groups of inhibitory interneurons (SOM-cells and PV-cells) displayed distinct vulnerability in the perirhinal cortex of APP/PS1 mice and AD patients. SOM-positive neurons were notably sensitive and exhibited a dramatic decrease in the perirhinal cortex of 6-month-old transgenic mice (57% and 61% in areas 36 and 35, respectively) and, most importantly, in AD patients (91% in Braak V-VI cases). In addition, this interneuron degenerative process seems to occur in parallel, and closely related, with the progression of the amyloid pathology. However, the population expressing PV was unaffected in APP/PS1 mice while in AD brains suffered a pronounced and significant loss (69%). As a key component of cortico-hippocampal networks, the perirhinal cortex plays an important role in memory processes, especially in familiarity-based memory recognition. Therefore, disrupted functional connectivity of this cortical region, as a result of the early SOM and PV neurodegeneration, might contribute to the altered brain rhythms and cognitive failures observed in the initial clinical phase of AD patients. Finally, these findings highlight the failure of amyloidogenic AD models to fully recapitulate the selective neuronal degeneration occurring in humans.
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Affiliation(s)
- Elisabeth Sanchez-Mejias
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Cristina Nuñez-Diaz
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Raquel Sanchez-Varo
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Angela Gomez-Arboledas
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Juan Antonio Garcia-Leon
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Juan Jose Fernandez-Valenzuela
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Marina Mejias-Ortega
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Laura Trujillo-Estrada
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - David Baglietto-Vargas
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Ines Moreno-Gonzalez
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Jose Carlos Davila
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Javier Vitorica
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Dpto. Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Sevilla, Spain.,Instituto de Biomedicina de Sevilla (IBIS)-Hospital Universitario Virgen del Rocio/CSIC/Universidad de Sevilla, Sevilla, Spain
| | - Antonia Gutierrez
- Dpto. Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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15
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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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16
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Tzioras M, Davies C, Newman A, Jackson R, Spires‐Jones T. Invited Review: APOE at the interface of inflammation, neurodegeneration and pathological protein spread in Alzheimer's disease. Neuropathol Appl Neurobiol 2019; 45:327-346. [PMID: 30394574 PMCID: PMC6563457 DOI: 10.1111/nan.12529] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 10/27/2018] [Indexed: 12/13/2022]
Abstract
Despite more than a century of research, the aetiology of sporadic Alzheimer's disease (AD) remains unclear and finding disease modifying treatments for AD presents one of the biggest medical challenges of our time. AD pathology is characterized by deposits of aggregated amyloid beta (Aβ) in amyloid plaques and aggregated tau in neurofibrillary tangles. These aggregates begin in distinct brain regions and spread throughout the brain in stereotypical patterns. Neurodegeneration, comprising loss of synapses and neurons, occurs in brain regions with high tangle pathology, and an inflammatory response of glial cells appears in brain regions with pathological aggregates. Inheriting an apolipoprotein E ε4 (APOE4) allele strongly increases the risk of developing AD for reasons that are not yet entirely clear. Substantial amounts of evidence support a role for APOE in modulating the aggregation and clearance of Aβ, and data have been accumulating recently implicating APOE4 in exacerbating neurodegeneration, tau pathology and inflammation. We hypothesize that APOE4 influences all the pathological hallmarks of AD and may sit at the interface between neurodegeneration, inflammation and the spread of pathologies through the brain. Here, we conducted a systematic search of the literature and review evidence supporting a role for APOE4 in neurodegeneration and inflammation. While there is no direct evidence yet for APOE4 influencing the spread of pathology, we postulate that this may be found in future based on the literature reviewed here. In conclusion, this review highlights the importance of understanding the role of APOE in multiple important pathological mechanisms in AD.
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Affiliation(s)
- M. Tzioras
- UK Dementia Research Institute and Centre for Discovery Brain SciencesThe University of EdinburghEdinburghUK
| | - C. Davies
- UK Dementia Research Institute and Centre for Discovery Brain SciencesThe University of EdinburghEdinburghUK
| | - A. Newman
- UK Dementia Research Institute and Centre for Discovery Brain SciencesThe University of EdinburghEdinburghUK
| | - R. Jackson
- UK Dementia Research Institute and Centre for Discovery Brain SciencesThe University of EdinburghEdinburghUK
- Massachusetts General Hospital and Harvard Medical SchoolCharlestownMAUSA
| | - T. Spires‐Jones
- UK Dementia Research Institute and Centre for Discovery Brain SciencesThe University of EdinburghEdinburghUK
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17
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Duron E, Vidal JS, Grousselle D, Gabelle A, Lehmann S, Pasquier F, Bombois S, Buée L, Allinquant B, Schraen-Maschke S, Baret C, Rigaud AS, Hanon O, Epelbaum J. Somatostatin and Neuropeptide Y in Cerebrospinal Fluid: Correlations With Amyloid Peptides Aβ 1-42 and Tau Proteins in Elderly Patients With Mild Cognitive Impairment. Front Aging Neurosci 2018; 10:297. [PMID: 30327597 PMCID: PMC6174237 DOI: 10.3389/fnagi.2018.00297] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 09/10/2018] [Indexed: 12/23/2022] Open
Abstract
A combination of low cerebrospinal fluid (CSF) Amyloid β1–42 (Aβ1–42) and high Total-Tau (T-Tau) and Phosphorylated-Tau (P-Tau) occurs at a prodromal stage of Alzheimer’s disease (AD) and recent findings suggest that network abnormalities and interneurons dysfunction contribute to cognitive deficits. Somatostatin (SOM) and Neuropeptide Y (NPY) are two neuropeptides which are expressed in GABAergic interneurons with different fates in AD the former only being markedly affected. The aim of this study was to analyze CSF SOM, NPY and CSF Aβ1–42; T-Tau, P-Tau relationships in 43 elderly mild cognitively impairment (MCI) participants from the Biomarker of AmyLoïd pepTide and AlZheimer’s disease Risk (BALTAZAR) cohort. In these samples, CSF SOM and CSF Aβ1–42 on the one hand, and CSF NPY and CSF T-Tau and P-Tau on the other hand are positively correlated. CSF SOM and NPY concentrations should be further investigated to determine if they can stand for early AD biomarkers. Clinical Trial Registration: www.ClinicalTrials.gov, identifier #NCT01315639.
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Affiliation(s)
- Emmanuelle Duron
- AP-HP, Hôpital Broca, Service de Gériatrie, Paris, France.,Université Sorbonne Paris Cité, UMR-S894, INSERM Université Paris Descartes, Centre de Psychiatrie et Neuroscience, Paris, France.,APHP, Hôpital Paul Brousse, Service de Gériatrie du Dr Karoubi, Villejuif, France.,Université Paris-Sud 11, Centre de Recherche en Épidemiologie et Santé des Population- Depression et Antidépresseurs, INSERM UMR-1178, Le Kremlin-Bicêtre, France
| | - Jean-Sébastien Vidal
- AP-HP, Hôpital Broca, Service de Gériatrie, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Dominique Grousselle
- Université Sorbonne Paris Cité, UMR-S894, INSERM Université Paris Descartes, Centre de Psychiatrie et Neuroscience, Paris, France
| | - Audrey Gabelle
- Memory Research and Resources Center, Gui de Chauliac Hospital, University of Montpellier, Montpellier, France
| | - Sylvain Lehmann
- Laboratoire de Biochimie Protéomique Clinique, CHU Montpellier, University of Montpellier, INSERM, Montpellier, France
| | - Florence Pasquier
- University of Lille, INSERM 1171, CHU, Centre Mémoire (CMRR) Distalz, Lille, France
| | | | - Luc Buée
- University of Lille, INSERM 1171, CHU, Centre Mémoire (CMRR) Distalz, Lille, France
| | - Bernadette Allinquant
- Université Sorbonne Paris Cité, UMR-S894, INSERM Université Paris Descartes, Centre de Psychiatrie et Neuroscience, Paris, France
| | | | - Christiane Baret
- UF de Neurobiologie, Centre Biologie Pathologie du CHU-Lille, Lille, France
| | - Anne-Sophie Rigaud
- AP-HP, Hôpital Broca, Service de Gériatrie, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Olivier Hanon
- AP-HP, Hôpital Broca, Service de Gériatrie, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Jacques Epelbaum
- Université Sorbonne Paris Cité, UMR-S894, INSERM Université Paris Descartes, Centre de Psychiatrie et Neuroscience, Paris, France.,MECADEV UMR 7179 CNRS, Muséum National d'Histoire Naturelle, Paris, France
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18
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Duron E, Vidal JS, Grousselle D, Gabelle A, Lehmann S, Pasquier F, Bombois S, Buée L, Allinquant B, Schraen-Maschke S, Baret C, Rigaud AS, Hanon O, Epelbaum J. Somatostatin and Neuropeptide Y in Cerebrospinal Fluid: Correlations With Amyloid Peptides Aβ1–42 and Tau Proteins in Elderly Patients With Mild Cognitive Impairment. Front Aging Neurosci 2018. [DOI: 10.3389/fnagi.2018.00297
expr 920238904 + 834128533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
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19
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Moderate decline in select synaptic markers in the prefrontal cortex (BA9) of patients with Alzheimer's disease at various cognitive stages. Sci Rep 2018; 8:938. [PMID: 29343737 PMCID: PMC5772053 DOI: 10.1038/s41598-018-19154-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 12/22/2017] [Indexed: 01/28/2023] Open
Abstract
Synaptic loss, plaques and neurofibrillary tangles are viewed as hallmarks of Alzheimer's disease (AD). This study investigated synaptic markers in neocortical Brodmann area 9 (BA9) samples from 171 subjects with and without AD at different levels of cognitive impairment. The expression levels of vesicular glutamate transporters (VGLUT1&2), glutamate uptake site (EAAT2), post-synaptic density protein of 95 kD (PSD95), vesicular GABA/glycine transporter (VIAAT), somatostatin (som), synaptophysin and choline acetyl transferase (ChAT) were evaluated. VGLUT2 and EAAT2 were unaffected by dementia. The VGLUT1, PSD95, VIAAT, som, ChAT and synaptophysin expression levels significantly decreased as dementia progressed. The maximal decrease varied between 12% (synaptophysin) and 42% (som). VGLUT1 was more strongly correlated with dementia than all of the other markers (polyserial correlation = -0.41). Principal component analysis using these markers was unable to differentiate the CDR groups from one another. Therefore, the status of the major synaptic markers in BA9 does not seem to be linked to the cognitive status of AD patients. The findings of this study suggest that the loss of synaptic markers in BA9 is a late event that is only weakly related to AD dementia.
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Sex- and age-specific modulation of brain GABA levels in a mouse model of Alzheimer's disease. Neurobiol Aging 2017; 62:168-179. [PMID: 29154037 DOI: 10.1016/j.neurobiolaging.2017.10.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 10/05/2017] [Accepted: 10/16/2017] [Indexed: 01/12/2023]
Abstract
Age and sex are risk factors of Alzheimer's disease (AD). Among the neurotransmitter systems, gamma-aminobutyric acid (GABA) has been implicated in AD pathogenesis but the relevance of sex-specific GABAergic dysfunction during AD progression remains unknown. In the present study, we utilized state-of-the-art high-resolution magic angle spinning nuclear magnetic resonance to systematically monitor the brain region-, age-, and sex-specific modulation of GABA levels in wild-type and Tg2576 mice with amyloid pathology. In addition, we followed the possible role of reactive astrocytes in sex-specific GABA modulation. In female Tg2576 mice, hippocampal GABA levels were significantly elevated, along with higher number of reactive astrocytes and amyloid deposition. The elevated GABA was found to be produced via the monoamine oxidase-B route from putrescine in reactive astrocytes, more substantially in female than male mice, thus suggesting a role of astrocytes in memory impairment and sex-related differences in AD. Our results paint a coherent model of memory impairment in AD and signify that dynamic changes in regional GABA may be at the root of marked sex disparities observed in AD.
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NMDAR hypofunction and somatostatin-expressing GABAergic interneurons and receptors: A newly identified correlation and its effects in schizophrenia. SCHIZOPHRENIA RESEARCH-COGNITION 2017; 8:1-6. [PMID: 28740825 PMCID: PMC5514309 DOI: 10.1016/j.scog.2017.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 02/21/2017] [Accepted: 02/22/2017] [Indexed: 12/20/2022]
Abstract
This review investigates the association between N-methyl-d-Aspartate receptor (NMDAR) hypofunction and somatostatin-expressing GABAergic interneurons (SST +) and how it contributes to the cognitive deficits observed in schizophrenia (SZ). This is based on evidence that NMDAR antagonists caused symptoms resembling SZ in healthy individuals. NMDAR hypofunction in GABAergic interneurons results in the modulation of the cortical network oscillation, particularly in the gamma range (30–80 Hz). These gamma-band oscillation (GBO) abnormalities were found to lead to the cognitive deficits observed in the disorder. Postmortem mRNA studies have shown that SST decreased more significantly than any other biomarker in schizophrenic subjects. The functional role of Somatostatin (SST) in the aetiology of SZ can be studied through its receptors. Genetic knockout studies in animal models in Huntington's disease (HD) have shown that a specific SST receptor, SSTR2, is increased along with the increased NMDAR activity, with opposing patterns observed in SZ. A direct correlation between SSTR and NMDAR is hence inferred in this review with the hope of finding a potential new therapeutic target for the treatment of SZ and related neurological conditions.
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Sanchez-Mut JV, Heyn H, Vidal E, Delgado-Morales R, Moran S, Sayols S, Sandoval J, Ferrer I, Esteller M, Gräff J. Whole genome grey and white matter DNA methylation profiles in dorsolateral prefrontal cortex. Synapse 2017; 71. [PMID: 28105729 DOI: 10.1002/syn.21959] [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: 09/30/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 12/11/2022]
Abstract
The brain's neocortex is anatomically organized into grey and white matter, which are mainly composed by neuronal and glial cells, respectively. The neocortex can be further divided in different Brodmann areas according to their cytoarchitectural organization, which are associated with distinct cortical functions. There is increasing evidence that brain development and function are governed by epigenetic processes, yet their contribution to the functional organization of the neocortex remains incompletely understood. Herein, we determined the DNA methylation patterns of grey and white matter of dorsolateral prefrontal cortex (Brodmann area 9), an important region for higher cognitive skills that is particularly affected in various neurological diseases. For avoiding interindividual differences, we analyzed white and grey matter from the same donor using whole genome bisulfite sequencing, and for validating their biological significance, we used Infinium HumanMethylation450 BeadChip and pyrosequencing in ten and twenty independent samples, respectively. The combination of these analysis indicated robust grey-white matter differences in DNA methylation. What is more, cell type-specific markers were enriched among the most differentially methylated genes. Interestingly, we also found an outstanding number of grey-white matter differentially methylated genes that have previously been associated with Alzheimer's, Parkinson's, and Huntington's disease, as well as Multiple and Amyotrophic lateral sclerosis. The data presented here thus constitute an important resource for future studies not only to gain insight into brain regional as well as grey and white matter differences, but also to unmask epigenetic alterations that might underlie neurological and neurodegenerative diseases.
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Affiliation(s)
- Jose Vicente Sanchez-Mut
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Brain Mind Institute, Lausanne, CH-1015, Switzerland
| | - Holger Heyn
- Single Cell Genomics Unit, Centre Nacional d'Anàlisi Genòmica, Barcelona, Catalonia, E-08028, Spain
| | - Enrique Vidal
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona E-08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Raúl Delgado-Morales
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program, Institut d'Investigació Biomedica de Bellvitge, Barcelona, E-08908, Spain.,Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Universiteitssingel 50, Maastricht, MD 6200, The Netherlands
| | - Sebastian Moran
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program, Institut d'Investigació Biomedica de Bellvitge, Barcelona, E-08908, Spain
| | - Sergi Sayols
- Bioinformatics Core Facility, Institute of Molecular Biology, Mainz, D-55128, Germany
| | - Juan Sandoval
- Biomarkers and Precision Medicine Unit, Health Research Institute La Fe, Valencia, 46026, Spain
| | - Isidre Ferrer
- Institute of Neuropathology, Bellvitge University Hospital, University of Barcelona, Centre for Biomedical Research on Neurodegenerative Diseases (CIBERNED), E-08908 Hospitalet de Llobregat, Spain
| | - Manel Esteller
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program, Institut d'Investigació Biomedica de Bellvitge, Barcelona, E-08908, Spain
| | - Johannes Gräff
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Brain Mind Institute, Lausanne, CH-1015, Switzerland
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Viollet C, Simon A, Tolle V, Labarthe A, Grouselle D, Loe-Mie Y, Simonneau M, Martel G, Epelbaum J. Somatostatin-IRES-Cre Mice: Between Knockout and Wild-Type? Front Endocrinol (Lausanne) 2017; 8:131. [PMID: 28674519 PMCID: PMC5474965 DOI: 10.3389/fendo.2017.00131] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/29/2017] [Indexed: 01/24/2023] Open
Abstract
The neuropeptide somatostatin (SOM) is widely expressed in rodent brain and somatostatin-IRES-Cre (SOM-cre) mouse strains are increasingly used to unravel the physiology of SOM-containing neurons. However, while knock-in targeting strategy greatly improves Cre-Lox system accuracy, recent reports have shown that genomic insertion of Cre construct per se can markedly affect physiological function. We show that Cre transgene insertion into the 3'UTR of the somatostatin gene leads to the selective and massive depletion of endogenous SOM in all tested brain regions. It also strongly impacts SOM-related neuroendocrine responses in a similar manner to what has been reported for SST KO mice: increased corticosterone levels after 30-min restraint stress, decreased amplitude and regularity of ultradian growth hormone secretory patterns accompanied by changes in sexually dimorphic liver gene expression (serpina1, Cyp2b9, Cyp2a4, Cyp2d9, and Cyp7b1). In addition to demonstrating the need for examination of the consequences of Cre transgenesis, these results also reveal how this SOM-cre strain may be a useful tool in studying the functional consequences of moderate to low SOM levels as reported in neurological and psychiatric disorders.
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Affiliation(s)
- Cécile Viollet
- INSERM U894, Centre de Psychiatrie et Neurosciences, Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
- *Correspondence: Cécile Viollet, ; Jacques Epelbaum,
| | - Axelle Simon
- INSERM U894, Centre de Psychiatrie et Neurosciences, Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
| | - Virginie Tolle
- INSERM U894, Centre de Psychiatrie et Neurosciences, Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
| | - Alexandra Labarthe
- INSERM U894, Centre de Psychiatrie et Neurosciences, Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
| | - Dominique Grouselle
- INSERM U894, Centre de Psychiatrie et Neurosciences, Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
| | - Yann Loe-Mie
- INSERM U894, Centre de Psychiatrie et Neurosciences, Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
| | - Michel Simonneau
- INSERM U894, Centre de Psychiatrie et Neurosciences, Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Paris-Saclay, Université Paris-Saclay, Orsay, France
| | - Guillaume Martel
- INSERM U894, Centre de Psychiatrie et Neurosciences, Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
| | - Jacques Epelbaum
- INSERM U894, Centre de Psychiatrie et Neurosciences, Université Paris-Descartes, Sorbonne Paris-Cité, Paris, France
- MECADEV UMR 7179 CNRS, Muséum National d’Histoire Naturelle, Brunoy, France
- *Correspondence: Cécile Viollet, ; Jacques Epelbaum,
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Chohan MO, Moore H. Interneuron Progenitor Transplantation to Treat CNS Dysfunction. Front Neural Circuits 2016; 10:64. [PMID: 27582692 PMCID: PMC4987325 DOI: 10.3389/fncir.2016.00064] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 08/02/2016] [Indexed: 11/13/2022] Open
Abstract
Due to the inadequacy of endogenous repair mechanisms diseases of the nervous system remain a major challenge to scientists and clinicians. Stem cell based therapy is an exciting and viable strategy that has been shown to ameliorate or even reverse symptoms of CNS dysfunction in preclinical animal models. Of particular importance has been the use of GABAergic interneuron progenitors as a therapeutic strategy. Born in the neurogenic niches of the ventral telencephalon, interneuron progenitors retain their unique capacity to disperse, integrate and induce plasticity in adult host circuitries following transplantation. Here we discuss the potential of interneuron based transplantation strategies as it relates to CNS disease therapeutics. We also discuss mechanisms underlying their therapeutic efficacy and some of the challenges that face the field.
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Affiliation(s)
- Muhammad O Chohan
- Department of Integrative Neuroscience, New York State Psychiatric Institute, New YorkNY, USA; Department of Psychiatry, Columbia University, New YorkNY, USA
| | - Holly Moore
- Department of Integrative Neuroscience, New York State Psychiatric Institute, New YorkNY, USA; Department of Psychiatry, Columbia University, New YorkNY, USA
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Modulation of Irisin and Physical Activity on Executive Functions in Obesity and Morbid obesity. Sci Rep 2016; 6:30820. [PMID: 27476477 PMCID: PMC4967861 DOI: 10.1038/srep30820] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 07/06/2016] [Indexed: 02/08/2023] Open
Abstract
Whether the executive profile is different between obesity (OB) and morbid obesity (MO) remains unclear. Recent evidence suggests that physical activity (PA) can act as a cognitive enhancer. Irisin is a recently discovered hormone associated with some of the positive effects of PA. The objective of the study was to investigate the executive profile in OB and MO, and to explore the role of PA and irisin. 114 participants were included (21 OB, 44 MO and 49 healthy controls-HC) in the study and assessed with the Wisconsin Card Sorting Test, Stroop Color and Word Test, and Iowa Gambling Task. All participants were female, aged between 18 and 60 years. Results showed a similar dysfunctional profile on decision making in OB and MO compared with HC. Thus, no specific neuropsychological profiles between OB and MO can be clearly observed in our sample. However, a negative correlation was found between irisin and executive functioning. These results demonstrate a specific executive profile in OB and a relevant and negative modulation of irisin on executive functioning. Although irisin might be a promising target for the treatment of obesity, its effects on cognition might be considered when thinking about its therapeutic use.
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Enhancing GABA Signaling during Middle Adulthood Prevents Age-Dependent GABAergic Interneuron Decline and Learning and Memory Deficits in ApoE4 Mice. J Neurosci 2016; 36:2316-22. [PMID: 26888940 DOI: 10.1523/jneurosci.3815-15.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED Apolipoprotein E4 (apoE4) is the major genetic risk factor for Alzheimer's disease (AD). However, the underlying mechanisms are still poorly understood. We previously reported that female apoE4 knock-in (KI) mice had an age-dependent decline in hilar GABAergic interneurons that correlated with the extent of learning and memory deficits, as determined by Morris water maze (MWM), in aged mice. Enhancing GABA signaling by treating aged apoE4-KI mice with the GABAA receptor potentiator pentobarbital (PB) for 4 weeks before and during MWM rescued the learning and memory deficits. Here, we report that withdrawal of PB treatment for 2 weeks before MWM abolished the rescue in aged apoE4-KI mice, suggesting the importance of continuously enhancing GABA signaling in the rescue. However, treating apoE4-KI mice during middle adulthood (9-11 months of age) with PB for 6 weeks prevented age-dependent hilar GABAergic interneuron decline and learning and memory deficits, when examined at 16 month of age. These data imply that increasing inhibitory tone after substantial GABAergic interneuron loss may be an effective symptomatic, but not a disease-modifying, treatment for AD related to apoE4, whereas a similar intervention before substantial interneuron loss could be a disease-modifying therapeutic. SIGNIFICANCE STATEMENT We previously reported that female apoE4-KI mice had an age-dependent decline in hilar GABAergic interneurons that correlated with the extent of cognitive deficits in aged mice. The current study demonstrates that enhancing GABA signaling by treating aged apoE4-KI mice with a GABAA receptor potentiator pentobarbital (PB) before and during behavioral tests rescued the cognitive deficits; but withdrawal of PB treatment for 2 weeks before the tests abolished the rescue, suggesting the importance of continuously enhancing GABA signaling. However, treating apoE4-KI mice during middle adulthood with PB for a short period of time prevented age-dependent hilar GABAergic interneuron decline and cognitive deficits late in life, suggesting early intervention by enhancing GABA signaling as a potential strategy to prevent AD related to apoE4.
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Li Y, Sun H, Chen Z, Xu H, Bu G, Zheng H. Implications of GABAergic Neurotransmission in Alzheimer's Disease. Front Aging Neurosci 2016; 8:31. [PMID: 26941642 PMCID: PMC4763334 DOI: 10.3389/fnagi.2016.00031] [Citation(s) in RCA: 158] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/08/2016] [Indexed: 01/02/2023] Open
Abstract
Alzheimer's disease (AD) is characterized pathologically by the deposition of β-amyloid peptides (Aβ) and the accumulation of neurofibrillary tangles (NFTs) composed of hyper-phosphorylated tau. Regardless of the pathological hallmarks, synaptic dysfunction is widely accepted as a causal event in AD. Of the two major types of synapses in the central nervous system (CNS): glutamatergic and GABAergic, which provide excitatory and inhibitory outputs respectively, abundant data implicate an impaired glutamatergic system during disease progression. However, emerging evidence supports the notion that disrupted default neuronal network underlies impaired memory, and that alterations of GABAergic circuits, either plays a primary role or as a compensatory response to excitotoxicity, may also contribute to AD by disrupting the overall network function. The goal of this review is to provide an overview of the involvement of Aβ, tau and apolipoprotein E4 (apoE4), the major genetic risk factor in late-onset AD (LOAD), in GABAergic neurotransmission and the potential of modulating the GABAergic function as AD therapy.
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Affiliation(s)
- Yanfang Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, China
| | - Hao Sun
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, China
| | - Zhicai Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, China
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen UniversityXiamen, China; Neurodegenerative Disease Research Program, Sanford-Burnham Medical Research InstituteLa Jolla, CA, USA
| | - Guojun Bu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen UniversityXiamen, China; Department of Neuroscience, Mayo ClinicJacksonville, FL, USA
| | - Hui Zheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen UniversityXiamen, China; The Interdepartmental Program of Translational Biology and Molecular Medicine, Huffington Center on Aging, Baylor College of MedicineHouston, TX, USA
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28
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Potential of GABA-ergic cell therapy for schizophrenia, neuropathic pain, and Alzheimer's and Parkinson's diseases. Brain Res 2015; 1638:74-87. [PMID: 26423935 DOI: 10.1016/j.brainres.2015.09.019] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 08/26/2015] [Accepted: 09/08/2015] [Indexed: 12/17/2022]
Abstract
Several neurological and psychiatric disorders present hyperexcitability of neurons in specific regions of the brain or spinal cord, partly because of some loss and/or dysfunction of gamma-amino butyric acid positive (GABA-ergic) inhibitory interneurons. Strategies that enhance inhibitory neurotransmission in the affected brain regions may therefore ease several or most deficits linked to these disorders. This perception has incited a huge interest in testing the efficacy of GABA-ergic interneuron cell grafting into regions of the brain or spinal cord exhibiting hyperexcitability, dearth of GABA-ergic interneurons or impaired inhibitory neurotransmission, using preclinical models of neurological and psychiatric disorders. Interneuron progenitors from the embryonic ventral telencephalon capable of differentiating into diverse subclasses of interneurons have particularly received much consideration because of their ability for dispersion, migration and integration with the host neural circuitry after grafting. The goal of this review is to discuss the premise, scope and advancement of GABA-ergic cell therapy for easing neurological deficits in preclinical models of schizophrenia, chronic neuropathic pain, Alzheimer's disease and Parkinson's disease. As grafting studies in these prototypes have so far utilized either primary cells from the embryonic medial and lateral ganglionic eminences or neural progenitor cells expanded from these eminences as donor material, the proficiency of these cell types is highlighted. Moreover, future studies that are essential prior to considering the possible clinical application of these cells for the above neurological conditions are proposed. Particularly, the need for grafting studies utilizing medial ganglionic eminence-like progenitors generated from human pluripotent stem cells via directed differentiation approaches or somatic cells through direct reprogramming methods are emphasized. This article is part of a Special Issue entitled SI: PSC and the brain.
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Tong LM, Fong H, Huang Y. Stem cell therapy for Alzheimer's disease and related disorders: current status and future perspectives. Exp Mol Med 2015; 47:e151. [PMID: 25766620 PMCID: PMC4351411 DOI: 10.1038/emm.2014.124] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 11/19/2014] [Indexed: 12/31/2022] Open
Abstract
Underlying cognitive declines in Alzheimer's disease (AD) are the result of neuron and neuronal process losses due to a wide range of factors. To date, all efforts to develop therapies that target specific AD-related pathways have failed in late-stage human trials. As a result, an emerging consensus in the field is that treatment of AD patients with currently available drug candidates might come too late, likely as a result of significant neuronal loss in the brain. In this regard, cell-replacement therapies, such as human embryonic stem cell- or induced pluripotent stem cell-derived neural cells, hold potential for treating AD patients. With the advent of stem cell technologies and the ability to transform these cells into different types of central nervous system neurons and glial cells, some success in stem cell therapy has been reported in animal models of AD. However, many more steps remain before stem cell therapies will be clinically feasible for AD and related disorders in humans. In this review, we will discuss current research advances in AD pathogenesis and stem cell technologies; additionally, the potential challenges and strategies for using cell-based therapies for AD and related disorders will be discussed.
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Affiliation(s)
- Leslie M Tong
- Gladstone Institute of Neurological Disease, University of California, San Francisco, CA, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, CA, USA
| | - Helen Fong
- Gladstone Institute of Neurological Disease, University of California, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, CA, USA
| | - Yadong Huang
- Gladstone Institute of Neurological Disease, University of California, San Francisco, CA, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, CA, USA
- Department of Pathology, University of California, San Francisco, CA, USA
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Apolipoprotein E4 produced in GABAergic interneurons causes learning and memory deficits in mice. J Neurosci 2015; 34:14069-78. [PMID: 25319703 DOI: 10.1523/jneurosci.2281-14.2014] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Apolipoprotein (apo) E4 is expressed in many types of brain cells, is associated with age-dependent decline of learning and memory in humans, and is the major genetic risk factor for AD. To determine whether the detrimental effects of apoE4 depend on its cellular sources, we generated human apoE knock-in mouse models in which the human APOE gene is conditionally deleted in astrocytes, neurons, or GABAergic interneurons. Here we report that deletion of apoE4 in astrocytes does not protect aged mice from apoE4-induced GABAergic interneuron loss and learning and memory deficits. In contrast, deletion of apoE4 in neurons does protect aged mice from both deficits. Furthermore, deletion of apoE4 in GABAergic interneurons is sufficient to gain similar protection. This study demonstrates a detrimental effect of endogenously produced apoE4 on GABAergic interneurons that leads to learning and memory deficits in mice and provides a novel target for drug development for AD related to apoE4.
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31
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Huang Y, Mahley RW. Apolipoprotein E: structure and function in lipid metabolism, neurobiology, and Alzheimer's diseases. Neurobiol Dis 2014; 72 Pt A:3-12. [PMID: 25173806 PMCID: PMC4253862 DOI: 10.1016/j.nbd.2014.08.025] [Citation(s) in RCA: 441] [Impact Index Per Article: 44.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 08/06/2014] [Accepted: 08/20/2014] [Indexed: 12/01/2022] Open
Abstract
Apolipoprotein (apo) E is a multifunctional protein with central roles in lipid metabolism, neurobiology, and neurodegenerative diseases. It has three major isoforms (apoE2, apoE3, and apoE4) with different effects on lipid and neuronal homeostasis. A major function of apoE is to mediate the binding of lipoproteins or lipid complexes in the plasma or interstitial fluids to specific cell-surface receptors. These receptors internalize apoE-containing lipoprotein particles; thus, apoE participates in the distribution/redistribution of lipids among various tissues and cells of the body. In addition, intracellular apoE may modulate various cellular processes physiologically or pathophysiologically, including cytoskeletal assembly and stability, mitochondrial integrity and function, and dendritic morphology and function. Elucidation of the functional domains within this protein and of the three-dimensional structure of the major isoforms of apoE has contributed significantly to our understanding of its physiological and pathophysiological roles at a molecular level. It is likely that apoE, with its multiple cellular origins and multiple structural and biophysical properties, is involved widely in processes of lipid metabolism and neurobiology, possibly encompassing a variety of disorders of neuronal repair, remodeling, and degeneration by interacting with different factors through various pathways.
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Affiliation(s)
- Yadong Huang
- Gladstone Institute of Neurological Disease, University of California, San Francisco 94158, USA; Gladstone Institute of Cardiovascular Disease, University of California, San Francisco 94158, USA; Department of Neurology, University of California, San Francisco 94158, USA; Department of Pathology, University of California, San Francisco 94158, USA.
| | - Robert W Mahley
- Gladstone Institute of Neurological Disease, University of California, San Francisco 94158, USA; Gladstone Institute of Cardiovascular Disease, University of California, San Francisco 94158, USA; Department of Pathology, University of California, San Francisco 94158, USA; Department of Medicine, University of California, San Francisco 94158, USA
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32
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Martel G, Simon A, Nocera S, Kalainathan S, Pidoux L, Blum D, Leclère-Turbant S, Diaz J, Geny D, Moyse E, Videau C, Buée L, Epelbaum J, Viollet C. Aging, but not tau pathology, impacts olfactory performances and somatostatin systems in THY-Tau22 mice. Neurobiol Aging 2014; 36:1013-28. [PMID: 25433460 DOI: 10.1016/j.neurobiolaging.2014.10.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 10/01/2014] [Accepted: 10/24/2014] [Indexed: 11/15/2022]
Abstract
Somatostatin (SOM) cortical levels decline in Alzheimer's disease (AD) in correlation with cognitive impairment severity, the latter being closely related to the presence of neurofibrillary tangles. Impaired olfaction is another hallmark of AD tightly related to tau pathology in the olfactory pathways. Recent studies showed that SOM modulates olfactory processing, suggesting that alterations in SOM levels participate to olfactory deficits in AD. Herein, we first observed that human olfactory peduncle and cortex are enriched in SOM cells and fibers, in aged postmortem brains. Then, the possible link between SOM alterations and olfactory deficits was evaluated by exploring the impact of age and tau hyperphosphorylation on olfactory SOM networks and behavioral performances in THY-Tau22 mice, a tauopathy transgenic model. Distinct molecular repertoires of SOM peptide and receptors were associated to sensory or cortical olfactory processing structures. Aging mainly affected SOM neurotransmission in piriform and entorhinal cortex in wild-type mice, although olfactory performances decreased. However, no further olfactory impairment was evidenced in THY-Tau22 mice until 12 months although tau pathology early affected olfactory cortical structures. Thus, tau hyperphosphorylation per se has a limited impact on olfactory performances in THY-Tau22 mice.
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Affiliation(s)
- Guillaume Martel
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Axelle Simon
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Sonia Nocera
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Sahana Kalainathan
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Ludivine Pidoux
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - David Blum
- Inserm, UMR837, Jean-Pierre Aubert Research Centre, IMPRT, F-59000, Lille, France; Université de Lille, UDSL, F-59000, Lille, France
| | | | - Jorge Diaz
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - David Geny
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Emmanuel Moyse
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Catherine Videau
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Luc Buée
- Inserm, UMR837, Jean-Pierre Aubert Research Centre, IMPRT, F-59000, Lille, France; Université de Lille, UDSL, F-59000, Lille, France
| | - Jacques Epelbaum
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France
| | - Cécile Viollet
- Inserm, UMR894, Center for Psychiatry & Neuroscience, 75014, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006, Paris, France.
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Inhibitory interneuron progenitor transplantation restores normal learning and memory in ApoE4 knock-in mice without or with Aβ accumulation. J Neurosci 2014; 34:9506-15. [PMID: 25031394 DOI: 10.1523/jneurosci.0693-14.2014] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Excitatory and inhibitory balance of neuronal network activity is essential for normal brain function and may be of particular importance to memory. Apolipoprotein (apo) E4 and amyloid-β (Aβ) peptides, two major players in Alzheimer's disease (AD), cause inhibitory interneuron impairments and aberrant neuronal activity in the hippocampal dentate gyrus in AD-related mouse models and humans, leading to learning and memory deficits. To determine whether replacing the lost or impaired interneurons rescues neuronal signaling and behavioral deficits, we transplanted embryonic interneuron progenitors into the hippocampal hilus of aged apoE4 knock-in mice without or with Aβ accumulation. In both conditions, the transplanted cells developed into mature interneurons, functionally integrated into the hippocampal circuitry, and restored normal learning and memory. Thus, restricted hilar transplantation of inhibitory interneurons restores normal cognitive function in two widely used AD-related mouse models, highlighting the importance of interneuron impairments in AD pathogenesis and the potential of cell replacement therapy for AD. More broadly, it demonstrates that excitatory and inhibitory balance are crucial for learning and memory, and suggests an avenue for investigating the processes of learning and memory and their alterations in healthy aging and diseases.
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Leung L, Andrews-Zwilling Y, Yoon SY, Jain S, Ring K, Dai J, Wang MM, Tong L, Walker D, Huang Y. Apolipoprotein E4 causes age- and sex-dependent impairments of hilar GABAergic interneurons and learning and memory deficits in mice. PLoS One 2012; 7:e53569. [PMID: 23300939 PMCID: PMC3534053 DOI: 10.1371/journal.pone.0053569] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Accepted: 12/03/2012] [Indexed: 11/25/2022] Open
Abstract
Apolipoprotein (apo) E4 is the major genetic risk factor for Alzheimer's disease (AD). ApoE4 has sex-dependent effects, whereby the risk of developing AD is higher in apoE4-expressing females than males. However, the mechanism underlying the sex difference, in relation to apoE4, is unknown. Previous findings indicate that apoE4 causes age-dependent impairments of hilar GABAergic interneurons in female mice, leading to learning and memory deficits. Here, we investigate whether the detrimental effects of apoE4 on hilar GABAergic interneurons are sex-dependent using apoE knock-in (KI) mice across different ages. We found that in female apoE-KI mice, there was an age-dependent depletion of hilar GABAergic interneurons, whereby GAD67- or somatostatin-positive–but not NPY- or parvalbumin-positive–interneuron loss was exacerbated by apoE4. Loss of these neuronal populations was correlated with the severity of spatial learning deficits at 16 months of age in female apoE4-KI mice; however, this effect was not observed in female apoE3-KI mice. In contrast, we found an increase in the numbers of hilar GABAergic interneurons with advancing age in male apoE-KI mice, regardless of apoE genotype. Moreover, male apoE-KI mice showed a consistent ratio of hilar inhibitory GABAergic interneurons to excitatory mossy cells approximating 1.5 that is independent of apoE genotype and age, whereas female apoE-KI mice exhibited an age-dependent decrease in this ratio, which was exacerbated by apoE4. Interestingly, there are no apoE genotype effects on GABAergic interneurons in the CA1 and CA3 subregions of the hippocampus as well as the entorhinal and auditory cortexes. These findings suggest that the sex-dependent effects of apoE4 on developing AD is in part attributable to inherent sex-based differences in the numbers of hilar GABAergic interneurons, which is further modulated by apoE genotype.
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Affiliation(s)
- Laura Leung
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
| | - Yaisa Andrews-Zwilling
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
| | - Seo Yeon Yoon
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
| | - Sachi Jain
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, California, United States of America
| | - Karen Ring
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, California, United States of America
| | - Jessica Dai
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
| | - Max Mu Wang
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
| | - Leslie Tong
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, California, United States of America
| | - David Walker
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Gladstone Institute of Cardiovascular Disease, San Francisco, California, United States of America
| | - Yadong Huang
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Gladstone Institute of Cardiovascular Disease, San Francisco, California, United States of America
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
- Department of Pathology, University of California San Francisco, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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Andrews-Zwilling Y, Gillespie AK, Kravitz AV, Nelson AB, Devidze N, Lo I, Yoon SY, Bien-Ly N, Ring K, Zwilling D, Potter GB, Rubenstein JLR, Kreitzer AC, Huang Y. Hilar GABAergic interneuron activity controls spatial learning and memory retrieval. PLoS One 2012; 7:e40555. [PMID: 22792368 PMCID: PMC3390383 DOI: 10.1371/journal.pone.0040555] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 06/08/2012] [Indexed: 11/25/2022] Open
Abstract
Background Although extensive research has demonstrated the importance of excitatory granule neurons in the dentate gyrus of the hippocampus in normal learning and memory and in the pathogenesis of amnesia in Alzheimer's disease (AD), the role of hilar GABAergic inhibitory interneurons, which control the granule neuron activity, remains unclear. Methodology and Principal Findings We explored the function of hilar GABAergic interneurons in spatial learning and memory by inhibiting their activity through Cre-dependent viral expression of enhanced halorhodopsin (eNpHR3.0)—a light-driven chloride pump. Hilar GABAergic interneuron-specific expression of eNpHR3.0 was achieved by bilaterally injecting adeno-associated virus containing a double-floxed inverted open-reading frame encoding eNpHR3.0 into the hilus of the dentate gyrus of mice expressing Cre recombinase under the control of an enhancer specific for GABAergic interneurons. In vitro and in vivo illumination with a yellow laser elicited inhibition of hilar GABAergic interneurons and consequent activation of dentate granule neurons, without affecting pyramidal neurons in the CA3 and CA1 regions of the hippocampus. We found that optogenetic inhibition of hilar GABAergic interneuron activity impaired spatial learning and memory retrieval, without affecting memory retention, as determined in the Morris water maze test. Importantly, optogenetic inhibition of hilar GABAergic interneuron activity did not alter short-term working memory, motor coordination, or exploratory activity. Conclusions and Significance Our findings establish a critical role for hilar GABAergic interneuron activity in controlling spatial learning and memory retrieval and provide evidence for the potential contribution of GABAergic interneuron impairment to the pathogenesis of amnesia in AD.
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Affiliation(s)
- Yaisa Andrews-Zwilling
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
| | - Anna K. Gillespie
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, California, United States of America
| | - Alexxai V. Kravitz
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
| | - Alexandra B. Nelson
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
| | - Nino Devidze
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
| | - Iris Lo
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
| | - Seo Yeon Yoon
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
| | - Nga Bien-Ly
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, California, United States of America
| | - Karen Ring
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, California, United States of America
| | - Daniel Zwilling
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
| | - Gregory B. Potter
- Department of Psychiatry, University of California San Francisco, San Francisco, California, United States of America
| | - John L. R. Rubenstein
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, California, United States of America
- Department of Psychiatry, University of California San Francisco, San Francisco, California, United States of America
| | - Anatol C. Kreitzer
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, California, United States of America
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
- Department of Physiology, University of California San Francisco, San Francisco, California, United States of America
| | - Yadong Huang
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Gladstone Institute of Cardiovascular Disease, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, California, United States of America
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
- Department of Pathology, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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Probst G, Xu YZ. Small-molecule BACE1 inhibitors: a patent literature review (2006 - 2011). Expert Opin Ther Pat 2012; 22:511-40. [PMID: 22512789 DOI: 10.1517/13543776.2012.681302] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Alzheimer's disease is a devastating neurodegenerative disorder for which no disease-modifying therapy exists. The amyloid hypothesis, which implicates Aβ as the toxin initiating a biological cascade leading to neurodegeneration, is the most prominent theory concerning the underlying cause of the disease. BACE1 is one of two aspartyl proteinases that generate Aβ, thus inhibition of BACE1 has the potential to ameliorate the progression of Alzheimer's disease by abating the production of Aβ. AREAS COVERED This review chronicles small-molecule BACE1 inhibitors as described in the patent literature between 2006 and 2011 and their potential use as disease-modifying treatments for Alzheimer's disease. Over the past half a dozen years, numerous BACE1 inhibitors have been published in the patent applications, but often these contain a paltry amount of pertinent biological data (e.g. potency, selectivity, and efficacy). Fortunately, numerous relevant publications containing important data have appeared in the journal literature during this period. The goal in this effort was to create an amalgam of the two records to add value to this review. EXPERT OPINION The pharmaceutical industry has made tremendous progress in the development of small-molecule BACE1 inhibitors that lower Aβ in the central nervous system. Assuming the amyloid hypothesis is veracious, we anticipate a disease-modifying therapy to combat Alzheimer's disease is near.
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Affiliation(s)
- Gary Probst
- Elan Pharmaceuticals, Molecular Design, 180 Oyster Point Boulevard, South San Francisco, CA 94080, USA.
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Kleiber ML, Laufer BI, Wright E, Diehl EJ, Singh SM. Long-term alterations to the brain transcriptome in a maternal voluntary consumption model of fetal alcohol spectrum disorders. Brain Res 2012; 1458:18-33. [PMID: 22560501 DOI: 10.1016/j.brainres.2012.04.016] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 03/29/2012] [Accepted: 04/09/2012] [Indexed: 12/16/2022]
Abstract
Many women continue to consume low to moderate quantities of alcohol during pregnancy, which can result in the variable neurobehavioural effects in the absence of physiological abnormalities that characterize fetal alcohol spectrum disorders (FASD). Previously, we reported that a mouse model for FASD based on voluntary maternal ethanol consumption throughout gestation resulted in offspring that showed mild developmental delay, anxiety-related traits, and deficits in spatial learning. Here, we extend this model by evaluating the gene expression changes that occur in the adult brain of C57BL/6J mice prenatally exposed to ethanol via maternal preference drinking. The results of two independent expression array experiments indicate that ethanol induces subtle but consistent changes to global gene expression. Gene enrichment analysis showed over-represented gene ontology classifications of cellular, embryonic, and nervous system development. Molecular network analysis supported these classifications, with significant networks related to cellular and tissue development, free radical scavenging, and small molecule metabolism. Further, a number of genes identified have previously been implicated in FASD-relevant neurobehavioural phenotypes such as cognitive function (Ache, Bcl2, Cul4b, Dkc1, Ebp, Lcat, Nsdh1, Sstr3), anxiety (Bcl2), attention deficit hyperactivity disorder (Nsdh1), and mood disorders (Bcl2, Otx2, Sstr3). The results suggest a complex residual "footprint" of neurodevelopmental ethanol exposure that may provide a new perspective for identifying mechanisms that underlie the life-long persistence of FASD-related cognitive and behavioural alterations, including potential targets for treatment.
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Affiliation(s)
- Morgan L Kleiber
- Molecular Genetics Unit, Department of Biology, University of Western Ontario, London, Ontario, Canada N6A 5B7
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Abstract
There are still no effective treatments to prevent, halt, or reverse Alzheimer's disease, but research advances over the past three decades could change this gloomy picture. Genetic studies demonstrate that the disease has multiple causes. Interdisciplinary approaches combining biochemistry, molecular and cell biology, and transgenic modeling have revealed some of its molecular mechanisms. Progress in chemistry, radiology, and systems biology is beginning to provide useful biomarkers, and the emergence of personalized medicine is poised to transform pharmaceutical development and clinical trials. However, investigative and drug development efforts should be diversified to fully address the multifactoriality of the disease.
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Affiliation(s)
- Yadong Huang
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
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Martel G, Dutar P, Epelbaum J, Viollet C. Somatostatinergic systems: an update on brain functions in normal and pathological aging. Front Endocrinol (Lausanne) 2012; 3:154. [PMID: 23230430 PMCID: PMC3515867 DOI: 10.3389/fendo.2012.00154] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 11/20/2012] [Indexed: 11/29/2022] Open
Abstract
Somatostatin is highly expressed in mammalian brain and is involved in many brain functions such as motor activity, sleep, sensory, and cognitive processes. Five somatostatin receptors have been described: sst(1), sst(2) (A and B), sst(3), sst(4), and sst(5), all belonging to the G-protein-coupled receptor family. During the recent years, numerous studies contributed to clarify the role of somatostatin systems, especially long-range somatostatinergic interneurons, in several functions they have been previously involved in. New advances have also been made on the alterations of somatostatinergic systems in several brain diseases and on the potential therapeutic target they represent in these pathologies.
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Affiliation(s)
| | | | | | - Cécile Viollet
- *Correspondence: Cécile Viollet, Inserm UMR894 - Center for Psychiatry and Neuroscience, Université Paris Descartes, Sorbonne Paris Cité, 2 ter rue d’Alésia, 75014 Paris, France. e-mail:
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Feng DD, Yang SK, Loudes C, Simon A, Al-Sarraf T, Culler M, Alvear-Perez R, Llorens-Cortes C, Chen C, Epelbaum J, Gardette R. Ghrelin and obestatin modulate growth hormone-releasing hormone release and synaptic inputs onto growth hormone-releasing hormone neurons. Eur J Neurosci 2011; 34:732-44. [DOI: 10.1111/j.1460-9568.2011.07787.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Apolipoprotein E4 causes age- and Tau-dependent impairment of GABAergic interneurons, leading to learning and memory deficits in mice. J Neurosci 2010; 30:13707-17. [PMID: 20943911 DOI: 10.1523/jneurosci.4040-10.2010] [Citation(s) in RCA: 234] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Apolipoprotein E4 (apoE4) is the major genetic risk factor for Alzheimer's disease. However, the underlying mechanisms are unclear. We found that female apoE4 knock-in (KI) mice had an age-dependent decrease in hilar GABAergic interneurons that correlated with the extent of learning and memory deficits, as determined in the Morris water maze, in aged mice. Treating apoE4-KI mice with daily peritoneal injections of the GABA(A) receptor potentiator pentobarbital at 20 mg/kg for 4 weeks rescued the learning and memory deficits. In neurotoxic apoE4 fragment transgenic mice, hilar GABAergic interneuron loss was even more pronounced and also correlated with the extent of learning and memory deficits. Neurodegeneration and tauopathy occurred earliest in hilar interneurons in apoE4 fragment transgenic mice; eliminating endogenous Tau prevented hilar GABAergic interneuron loss and the learning and memory deficits. The GABA(A) receptor antagonist picrotoxin abolished this rescue, while pentobarbital rescued learning deficits in the presence of endogenous Tau. Thus, apoE4 causes age- and Tau-dependent impairment of hilar GABAergic interneurons, leading to learning and memory deficits in mice. Consequently, reducing Tau and enhancing GABA signaling are potential strategies to treat or prevent apoE4-related Alzheimer's disease.
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Fleisher-Berkovich S, Filipovich-Rimon T, Ben-Shmuel S, Hülsmann C, Kummer MP, Heneka MT. Distinct modulation of microglial amyloid β phagocytosis and migration by neuropeptides (i). J Neuroinflammation 2010; 7:61. [PMID: 20937084 PMCID: PMC2964654 DOI: 10.1186/1742-2094-7-61] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 10/11/2010] [Indexed: 01/04/2023] Open
Abstract
Microglial activation plays an integral role in the development and course of neurodegeneration. Although neuropeptides such as bradykinin (BK), somatostatin (SST), and endothelin (ET) are known to be important mediators of inflammation in the periphery, evidence of a similar function in brain is scarce. Using immunocytochemistry, we demonstrate the expression of receptors for BK (B1, B2 subtypes), ET (ETA, ETB subtypes) and SST (SST 2, 3, 4 subtypes) in primary microglia and microglial cell lines. Exposure of BV2 and N9, as well as primary microglial cells to BK or SST increased Aβ uptake in a concentration-dependent manner, whereas endothelin decreased Aβ uptake. This was caused by increased phagocytosis of Aβ since the rate of intracellular Aβ degradation remained unaffected. All neuropeptides increased chemotactic activity of microglia. In addition, BK reduced Aβ-induced expression of proinflammatory genes including iNOS and COX-2. ET decreased the Aβ-induced expression of monocyte chemoattractant protein 1 and interleukin-6. These results suggest that neuropeptides play an important role in chemotaxis and Aβ clearance and modulate the brain's response to neuroinflammatory processes.
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Affiliation(s)
- Sigal Fleisher-Berkovich
- Division of Clinical Neurosciences, Dept. of Neurology, University of Bonn Medical Center, Bonn, Germany
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Watson GS, Baker LD, Cholerton BA, Rhoads KW, Merriam GR, Schellenberg GD, Asthana S, Cherrier M, Craft S. Effects of insulin and octreotide on memory and growth hormone in Alzheimer's disease. J Alzheimers Dis 2010; 18:595-602. [PMID: 19625744 DOI: 10.3233/jad-2009-1165] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Both insulin alone and the somatostatin analogue octreotide alone facilitate memory in patients with Alzheimer's disease (AD). Since octreotide inhibits endogenous insulin secretion, the cognitive effects of insulin and octreotide may not be independent. This study tested the individual and interactive effects of insulin and octreotide on memory and plasma growth hormone (GH) levels in older adults. Participants were 16 memory-impaired (AD = 7, amnestic mild cognitive impairment = 9; apolipoprotein E [APOE] epsilon4- [no epsilon4 alleles] = 9, epsilon4+ [1-2 epsilon4 alleles] = 7), and 19 cognitively-intact older adults (APOE epsilon4- = 17, epsilon4+ = 1). On separate days, fasting participants received counterbalanced infusions of: 1) insulin (1 mU.kg(-1).min(-1)) and dextrose to maintain euglycemia; 2) octreotide (150 microg/h); 3) insulin, dextrose, and octreotide; or 4) saline. Story recall was the principal endpoint. Insulin alone facilitated delayed recall for epsilon4- patients, relative to epsilon4+ patients (P = 0.0012). Furthermore, epsilon4- patients with higher Mattis Dementia Rating Scale (DRS) scores had greater octreotide-induced memory facilitation (P = 0.0298). For healthy adults, octreotide facilitated memory (P = 0.0122). Unexpectedly, hyperinsulinemia with euglycemia increased GH levels in healthy controls (P = 0.0299). Thus, insulin and octreotide appear to regulate memory in older adults. APOE epsilon4 genotype modulates responses to insulin and octreotide. Finally, insulin may regulate GH levels during euglycemia.
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Affiliation(s)
- G Stennis Watson
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Healthcare System, Seattle, WA, USA
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Somatostatin, Alzheimer's disease and cognition: An old story coming of age? Prog Neurobiol 2009; 89:153-61. [DOI: 10.1016/j.pneurobio.2009.07.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Revised: 04/27/2009] [Accepted: 07/02/2009] [Indexed: 12/21/2022]
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Neprilysin and Insulin-Degrading Enzyme Levels Are Increased in Alzheimer Disease in Relation to Disease Severity. J Neuropathol Exp Neurol 2009; 68:902-14. [DOI: 10.1097/nen.0b013e3181afe475] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Expression of somatostatin and somatostatin receptor subtypes in Apolipoprotein D (ApoD) knockout mouse brain: An immunohistochemical analysis. J Chem Neuroanat 2009; 38:20-33. [PMID: 19465111 DOI: 10.1016/j.jchemneu.2009.05.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 04/30/2009] [Accepted: 05/12/2009] [Indexed: 01/08/2023]
Abstract
Apolipoprotein D (ApoD) is widely distributed in central and peripheral nervous system. ApoD expression has been shown to increase in several neurodegenerative and neuropsychiatric disorders, as well as during regeneration in the nervous system. Like ApoD, in the central nervous system somatostatin (SST) is widely present and functions as neurotransmitter and neuromodulator. The biological effects of SST are mediated via binding to five high-affinity G-protein coupled receptors termed SSTR1-5. Mice lacking ApoD exhibit reduced SST labeling in cortex and hippocampus and increased expression in striatum and amygdala without any noticeable changes in substantia nigra. Changes in SSTRs expressions have been described in several neurodegenerative disorders including Alzheimer's, Parkinson's and Huntington's diseases. In the present study, using SSTR1-5 receptor-specific antibodies, we mapped their distribution in wild type (wt) and ApoD knockout (ApoD(-/-)) mouse brain. SSTR1-5 expression was observed both as membrane and cytoplasmic protein and display regions and receptor specific differences between wt and ApoD(-/-) mice brains. In cortex and hippocampus, SSTR subtypes like immunoreactivity are decreased in ApoD(-/-) mice brain. Unlike cortex and hippocampus, in the striatum of ApoD(-/-) mice, projection neurons showed increased SSTR immunoreactivity, as compared to wt. Higher SSTR subtypes immunoreactivity is seen in substantia nigra pars compacta (SNpc) whereas lower in substantia nigra pars reticulata (SNpr) of ApoD(-/-) mice brains as compared to wt. Whereas, amygdala displayed SSTR subtypes changes in different nuclei of ApoD(-/-) mice in comparison to wt mice brain. Taken together, our results describe receptor and region specific changes in SST and SSTR subtypes expression in ApoD(-/-) mice brain, which may be linked to specific neurological disorders.
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Miners JS, Baig S, Palmer J, Palmer LE, Kehoe PG, Love S. Abeta-degrading enzymes in Alzheimer's disease. Brain Pathol 2008; 18:240-52. [PMID: 18363935 DOI: 10.1111/j.1750-3639.2008.00132.x] [Citation(s) in RCA: 280] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
In Alzheimer's disease (AD) Abeta accumulates because of imbalance between the production of Abeta and its removal from the brain. There is increasing evidence that in most sporadic forms of AD, the accumulation of Abeta is partly, if not in some cases solely, because of defects in its removal--mediated through a combination of diffusion along perivascular extracellular matrix, transport across vessel walls into the blood stream and enzymatic degradation. Multiple enzymes within the central nervous system (CNS) are capable of degrading Abeta. Most are produced by neurons or glia, but some are expressed in the cerebral vasculature, where reduced Abeta-degrading activity may contribute to the development of cerebral amyloid angiopathy (CAA). Neprilysin and insulin-degrading enzyme (IDE), which have been most extensively studied, are expressed both neuronally and within the vasculature. The levels of both of these enzymes are reduced in AD although the correlation with enzyme activity is still not entirely clear. Other enzymes shown capable of degrading Abetain vitro or in animal studies include plasmin; endothelin-converting enzymes ECE-1 and -2; matrix metalloproteinases MMP-2, -3 and -9; and angiotensin-converting enzyme (ACE). The levels of plasmin and plasminogen activators (uPA and tPA) and ECE-2 are reported to be reduced in AD. Reductions in neprilysin, IDE and plasmin in AD have been associated with possession of APOEepsilon4. We found no change in the level or activity of MMP-2, -3 or -9 in AD. The level and activity of ACE are increased, the level being directly related to Abeta plaque load. Up-regulation of some Abeta-degrading enzymes may initially compensate for declining activity of others, but as age, genetic factors and diseases such as hypertension and diabetes diminish the effectiveness of other Abeta-clearance pathways, reductions in the activity of particular Abeta-degrading enzymes may become critical, leading to the development of AD and CAA.
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Affiliation(s)
- James Scott Miners
- Dementia Research Group, University of Bristol Institute of Clinical Neurosciences, Frenchay Hospital, Bristol, UK
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Viollet C, Lepousez G, Loudes C, Videau C, Simon A, Epelbaum J. Somatostatinergic systems in brain: networks and functions. Mol Cell Endocrinol 2008; 286:75-87. [PMID: 17997029 DOI: 10.1016/j.mce.2007.09.007] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 09/10/2007] [Accepted: 09/19/2007] [Indexed: 12/21/2022]
Abstract
Somatostatin is abundantly expressed in mammalian brain. The peptide binds with high affinity to six somatostatin receptors, sst1, sst2A and B, sst3 to 5, all belonging to the G-protein-coupled receptor family. Recent advances in the neuroanatomy of somatostatin neurons and cellular distribution of sst receptors shed light on their functional roles in the neuronal network. Beside their initially described neuroendocrine role, somatostatin systems subserve neuromodulatory roles in the brain, influencing motor activity, sleep, sensory processes and cognitive functions, and are altered in brain diseases like affective disorders, epilepsia and Alzheimer's disease.
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Vepsäläinen S, Helisalmi S, Koivisto AM, Tapaninen T, Hiltunen M, Soininen H. Somatostatin genetic variants modify the risk for Alzheimer's disease among Finnish patients. J Neurol 2007; 254:1504-8. [PMID: 17987251 DOI: 10.1007/s00415-007-0539-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 01/22/2007] [Accepted: 02/05/2007] [Indexed: 10/22/2022]
Abstract
The levels of somatostatin are consistently decreased in the brain and cerebrospinal fluid of Alzheimer's disease (AD) patients. The somatostatin gene is located on chromosome 3q27.3 close to an association region identified in late-onset AD patients originating from Finland. Since somatostatin is a good candidate on both positional and functional grounds, we studied whether single nucleotide polymorphisms (SNPs) in the somatostatin gene were associated with AD in the Finnish population. We genotyped three SNPs within this gene in Finnish AD patients (n = 424) and non-demented controls (n = 466). AD patients were compared with non-demented control subjects using single-locus and haplotype approaches. In the whole study group, the age, sex and APOE adjusted OR for the risk of AD in C-allele carriers of the SNP rs4988 514 was 1.42 (p <0.05). Interestingly, in APOE epsilon4-allele carriers, the age and sex adjusted OR for the risk of AD in C-allele carriers of the rs4988 514 increased to 2.05 (p <0.01). Additionally, SNP rs4988514 may interact with the APOE epsilon4-allele to increase the risk of AD. Assessment of individual haplotype distributions revealed a 2-fold overrepresentation of the TCG haplotype of SNPs rs3864101, rs4988 514 and rs7624 906 in the AD APOE epsilon4-allele group (p <0.01). Conversely, a major haplotype TTG was significantly underrepresented among all the AD patients as well as APOE epsilon4-allele carrying AD patients. Thus the major haplotype TTG of somatostatin may have a protective effect against AD. This first genetic association study between somatostatin and AD indicates that genetic variations in the somatostatin gene may modify the risk for AD among Finnish AD subjects.
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Affiliation(s)
- Saila Vepsäläinen
- Department of Neurology, University Hospital and University of Kuopio, 70211, Kuopio, Finland.
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