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Peixoto DO, Bittencourt RR, Gasparotto J, Kessler FGC, Brum PO, Somensi N, Girardi CS, Dos Santos da Silva L, Outeiro TF, Moreira JCF, Gelain DP. Increased alpha-synuclein and neuroinflammation in the substantia nigra triggered by systemic inflammation are reversed by targeted inhibition of the receptor for advanced glycation end products (RAGE). J Neurochem 2024; 168:1587-1607. [PMID: 37661637 DOI: 10.1111/jnc.15956] [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: 03/16/2023] [Revised: 07/18/2023] [Accepted: 08/17/2023] [Indexed: 09/05/2023]
Abstract
The receptor for advanced glycation end products (RAGE) is a protein of the immunoglobulin superfamily capable of regulating inflammation. Considering the role of this receptor in the initiation and establishment of neuroinflammation, and the limited understanding of the function of RAGE in the maintenance of this condition, this study describes the effects of RAGE inhibition in the brain, through an intranasal treatment with the antagonist FPS-ZM1, in an animal model of chronic neuroinflammation induced by acute intraperitoneal injection of lipopolysaccharide (LPS). Seventy days after LPS administration (2 mg/kg, i.p.), Wistar rats received, intranasally, 1.2 mg of FPS-ZM1 over 14 days. On days 88 and 89, the animals were submitted to the open-field test and were killed on day 90 after the intraperitoneal injection of LPS. Our results indicate that blockade of encephalic RAGE attenuates LPS-induced chronic neuroinflammation in different brain regions. Furthermore, we found that intranasal FPS-ZM1 administration reduced levels of gliosis markers, RAGE ligands, and α-synuclein in the substantia nigra pars compacta. Additionally, the treatment also reversed the increase in S100 calcium-binding protein B (RAGE ligand) in the cerebrospinal fluid and the cognitive-behavioral deficits promoted by LPS-less time spent in the central zone of the open-field arena (more time in the lateral zones), decreased total distance traveled, and increased number of freezing episodes. In summary, our study demonstrates the prominent role of RAGE in the maintenance of a chronic neuroinflammatory state triggered by a single episode of systemic inflammation and also points to possible future RAGE-based therapeutic approaches to treat conditions in which chronic neuroinflammation and increased α-synuclein levels could play a relevant role, such as in Parkinson's disease.
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Affiliation(s)
- Daniel Oppermann Peixoto
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (ICBS-UFRGS), Porto Alegre, Brazil
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (UMH-CSIC), Sant Joan d'Alacant, Alicante, Spain
| | - Reykla Ramon Bittencourt
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (ICBS-UFRGS), Porto Alegre, Brazil
| | - Juciano Gasparotto
- Instituto de Ciências Biomédicas, Universidade Federal de Alfenas (ICB-UNIFAL), Alfenas, Brazil
| | - Flávio Gabriel Carazza Kessler
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (ICBS-UFRGS), Porto Alegre, Brazil
| | | | - Nauana Somensi
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (ICBS-UFRGS), Porto Alegre, Brazil
| | - Carolina Saibro Girardi
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (ICBS-UFRGS), Porto Alegre, Brazil
| | - Lucas Dos Santos da Silva
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (ICBS-UFRGS), Porto Alegre, Brazil
| | - Tiago Fleming Outeiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
- Max Planck Institute for Natural Sciences, Göttingen, Germany
- Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Framlington Place, Newcastle Upon Tyne, UK
- Scientific Employee with an Honorary Contract at Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Göttingen, Germany
| | - José Cláudio Fonseca Moreira
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (ICBS-UFRGS), Porto Alegre, Brazil
| | - Daniel Pens Gelain
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (ICBS-UFRGS), Porto Alegre, Brazil
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2
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Beckman D, Diniz GB, Ott S, Hobson B, Chaudhari AJ, Muller S, Chu Y, Takano A, Schwarz AJ, Yeh CL, McQuade P, Chakrabarty P, Kanaan NM, Quinton MS, Simen AA, Kordower JH, Morrison JH. Temporal progression of tau pathology and neuroinflammation in a rhesus monkey model of Alzheimer's disease. Alzheimers Dement 2024. [PMID: 39030748 DOI: 10.1002/alz.13868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 03/11/2024] [Accepted: 04/08/2024] [Indexed: 07/22/2024]
Abstract
INTRODUCTION The understanding of the pathological events in Alzheimer's disease (AD) has advanced dramatically, but the successful translation from rodent models into efficient human therapies is still problematic. METHODS To examine how tau pathology can develop in the primate brain, we injected 12 macaques with a dual tau mutation (P301L/S320F) into the entorhinal cortex (ERC). An investigation was performed using high-resolution microscopy, magnetic resonance imaging (MRI), positron emission tomography (PET), and fluid biomarkers to determine the temporal progression of the pathology 3 and 6 months after the injection. RESULTS Using quantitative microscopy targeting markers for neurodegeneration and neuroinflammation, as well as fluid and imaging biomarkers, we detailed the progression of misfolded tau spreading and the consequential inflammatory response induced by glial cells. DISCUSSION By combining the analysis of several in vivo biomarkers with extensive brain microscopy analysis, we described the initial steps of misfolded tau spreading and neuroinflammation in a monkey model highly translatable to AD patients. HIGHLIGHTS Dual tau mutation delivery in the entorhinal cortex induces progressive tau pathology in rhesus macaques. Exogenous human 4R-tau coaptates monkey 3R-tau during transneuronal spread, in a prion-like manner. Neuroinflammatory response is coordinated by microglia and astrocytes in response to tau pathology, with microglia targeting early tau pathology, while astrocytes engaged later in the progression, coincident with neuronal death. Monthly collection of CSF and plasma revealed a profile of changes in several AD core biomarkers, reflective of neurodegeneration and neuroinflammation as early as 1 month after injection.
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Affiliation(s)
- Danielle Beckman
- California National Primate Research Center, University of California Davis, Davis, California, USA
| | - Giovanne B Diniz
- California National Primate Research Center, University of California Davis, Davis, California, USA
| | - Sean Ott
- California National Primate Research Center, University of California Davis, Davis, California, USA
| | - Brad Hobson
- California National Primate Research Center, University of California Davis, Davis, California, USA
- Department of Radiology, School of Medicine, University of California Davis, Sacramento, California, USA
| | - Abhijit J Chaudhari
- California National Primate Research Center, University of California Davis, Davis, California, USA
- Department of Radiology, School of Medicine, University of California Davis, Sacramento, California, USA
| | - Scott Muller
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University, Tempe, Arizona, USA
| | - Yaping Chu
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University, Tempe, Arizona, USA
| | - Akihiro Takano
- Takeda Development Center Americas, Inc., Lexington, Massachusetts, USA
| | - Adam J Schwarz
- Takeda Development Center Americas, Inc., Lexington, Massachusetts, USA
| | - Chien-Lin Yeh
- Takeda Development Center Americas, Inc., Lexington, Massachusetts, USA
| | - Paul McQuade
- Takeda Development Center Americas, Inc., Lexington, Massachusetts, USA
| | - Paramita Chakrabarty
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida, USA
| | - Nicholas M Kanaan
- Department of Translational Neuroscience, College of Human Medicine, Michigan State University, Grand Rapids, Michigan, USA
| | - Maria S Quinton
- Takeda Development Center Americas, Inc., Lexington, Massachusetts, USA
| | - Arthur A Simen
- Takeda Development Center Americas, Inc., Lexington, Massachusetts, USA
| | - Jeffrey H Kordower
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University, Tempe, Arizona, USA
- Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois, USA
| | - John H Morrison
- California National Primate Research Center, University of California Davis, Davis, California, USA
- Department of Neurology, School of Medicine, University of California Davis, Sacramento, California, USA
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3
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Huang HZ, Ai WQ, Wei N, Zhu LS, Liu ZQ, Zhou CW, Deng MF, Zhang WT, Zhang JC, Yang CQ, Hu YZ, Han ZT, Zhang HH, Jia JJ, Wang J, Liu FF, Li K, Xu Q, Yuan M, Man H, Guo Z, Lu Y, Shu K, Zhu LQ, Liu D. Senktide blocks aberrant RTN3 interactome to retard memory decline and tau pathology in social isolated Alzheimer's disease mice. Protein Cell 2024; 15:261-284. [PMID: 38011644 PMCID: PMC10984625 DOI: 10.1093/procel/pwad056] [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] [Accepted: 11/06/2023] [Indexed: 11/29/2023] Open
Abstract
Sporadic or late-onset Alzheimer's disease (LOAD) accounts for more than 95% of Alzheimer's disease (AD) cases without any family history. Although genome-wide association studies have identified associated risk genes and loci for LOAD, numerous studies suggest that many adverse environmental factors, such as social isolation, are associated with an increased risk of dementia. However, the underlying mechanisms of social isolation in AD progression remain elusive. In the current study, we found that 7 days of social isolation could trigger pattern separation impairments and presynaptic abnormalities of the mossy fibre-CA3 circuit in AD mice. We also revealed that social isolation disrupted histone acetylation and resulted in the downregulation of 2 dentate gyrus (DG)-enriched miRNAs, which simultaneously target reticulon 3 (RTN3), an endoplasmic reticulum protein that aggregates in presynaptic regions to disturb the formation of functional mossy fibre boutons (MFBs) by recruiting multiple mitochondrial and vesicle-related proteins. Interestingly, the aggregation of RTN3 also recruits the PP2A B subunits to suppress PP2A activity and induce tau hyperphosphorylation, which, in turn, further elevates RTN3 and forms a vicious cycle. Finally, using an artificial intelligence-assisted molecular docking approach, we determined that senktide, a selective agonist of neurokinin3 receptors (NK3R), could reduce the binding of RTN3 with its partners. Moreover, application of senktide in vivo effectively restored DG circuit disorders in socially isolated AD mice. Taken together, our findings not only demonstrate the epigenetic regulatory mechanism underlying mossy fibre synaptic disorders orchestrated by social isolation and tau pathology but also reveal a novel potential therapeutic strategy for AD.
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Affiliation(s)
- He-Zhou Huang
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Wen-Qing Ai
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Na Wei
- Department of Pathology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450002, China
- Department of Pathology, School of Basic Medicine, Zhengzhou University, Zhengzhou 450002, China
| | - Ling-Shuang Zhu
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhi-Qiang Liu
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Chao-Wen Zhou
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Man-Fei Deng
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Wen-Tao Zhang
- The Second Affiliated Hospital, Department of Neurology, Hengyang Medical School, University of South China, Hengyang 421001, China
| | - Jia-Chen Zhang
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Chun-Qing Yang
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ya-Zhuo Hu
- Beijing Key Laboratory of Aging and Geriatrics, National Clinical Research Center for Geriatric Disease, Institute of Geriatrics, Chinese PLA General Hospital and Chinese PLA Medical Academy, Beijing 100853, China
| | - Zhi-Tao Han
- Beijing Key Laboratory of Aging and Geriatrics, National Clinical Research Center for Geriatric Disease, Institute of Geriatrics, Chinese PLA General Hospital and Chinese PLA Medical Academy, Beijing 100853, China
| | - Hong-Hong Zhang
- Beijing Key Laboratory of Aging and Geriatrics, National Clinical Research Center for Geriatric Disease, Institute of Geriatrics, Chinese PLA General Hospital and Chinese PLA Medical Academy, Beijing 100853, China
| | - Jian-Jun Jia
- Beijing Key Laboratory of Aging and Geriatrics, National Clinical Research Center for Geriatric Disease, Institute of Geriatrics, Chinese PLA General Hospital and Chinese PLA Medical Academy, Beijing 100853, China
| | - Jing Wang
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Fang-Fang Liu
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ke Li
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Qi Xu
- Department of Neurology, Union Hospital, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Mei Yuan
- The Second Affiliated Hospital, Department of Neurology, Hengyang Medical School, University of South China, Hengyang 421001, China
| | - Hengye Man
- Department of Biology, Boston University, Boston, MA 02215, USA
| | - Ziyuan Guo
- Center for Stem Cell and Organoid Medicine (CuSTOM), Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Youming Lu
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Kai Shu
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ling-Qiang Zhu
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Dan Liu
- Department of Medical Genetics, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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4
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Goodarzi G, Tehrani SS, Fana SE, Moradi-Sardareh H, Panahi G, Maniati M, Meshkani R. Crosstalk between Alzheimer's disease and diabetes: a focus on anti-diabetic drugs. Metab Brain Dis 2023; 38:1769-1800. [PMID: 37335453 DOI: 10.1007/s11011-023-01225-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 04/26/2023] [Indexed: 06/21/2023]
Abstract
Alzheimer's disease (AD) and Type 2 diabetes mellitus (T2DM) are two of the most common age-related diseases. There is accumulating evidence of an overlap in the pathophysiological mechanisms of these two diseases. Studies have demonstrated insulin pathway alternation may interact with amyloid-β protein deposition and tau protein phosphorylation, two essential factors in AD. So attention to the use of anti-diabetic drugs in AD treatment has increased in recent years. In vitro, in vivo, and clinical studies have evaluated possible neuroprotective effects of anti-diabetic different medicines in AD, with some promising results. Here we review the evidence on the therapeutic potential of insulin, metformin, Glucagon-like peptide-1 receptor agonist (GLP1R), thiazolidinediones (TZDs), Dipeptidyl Peptidase IV (DPP IV) Inhibitors, Sulfonylureas, Sodium-glucose Cotransporter-2 (SGLT2) Inhibitors, Alpha-glucosidase inhibitors, and Amylin analog against AD. Given that many questions remain unanswered, further studies are required to confirm the positive effects of anti-diabetic drugs in AD treatment. So to date, no particular anti-diabetic drugs can be recommended to treat AD.
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Affiliation(s)
- Golnaz Goodarzi
- Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Student Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Department of Pathobiology and Laboratory Sciences, School of Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Sadra Samavarchi Tehrani
- Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Student Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Saeed Ebrahimi Fana
- Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Student Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Ghodratollah Panahi
- Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmood Maniati
- English Department, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Reza Meshkani
- Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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5
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Chaudry O, Ndukwe K, Xie L, Figueiredo-Pereira M, Serrano P, Rockwell P. Females exhibit higher GluA2 levels and outperform males in active place avoidance despite increased amyloid plaques in TgF344-Alzheimer's rats. Sci Rep 2022; 12:19129. [PMID: 36352024 PMCID: PMC9646806 DOI: 10.1038/s41598-022-23801-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 11/05/2022] [Indexed: 11/11/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease that is most prevalent in females. While estrogen provides neuroprotection in females, sex mediated differences in the development of AD pathology are not fully elucidated. Therefore, comparing events between sexes in early-stage AD pathology may reveal more effective therapeutic targets of intervention. To address sex differences, we analyzed early-stage 9-month male and female TgF344-AD (Tg-AD) rats, an AD model carrying the APPswe and Presenilin 1 (PS1ΔE9) mutations that develops progressive age-dependent AD pathology similar to humans. Tg-AD females significantly outperformed Tg-AD males in the active place avoidance (aPAT) test that assesses hippocampal-dependent spatial learning and memory. However, comparisons between Tg-AD male or female rats and their WT counterparts showed significant deficits for female but not male rats. Nevertheless, Tg-AD females experienced significantly less hippocampal neuronal loss with higher GluA2 subunit levels than Tg-AD males. Unexpectedly, Tg-AD females displayed higher levels of hippocampal amyloid plaques than Tg-AD males. Thus, we propose that GluA2 may provide a neuroprotective function for Tg-AD females in our rat model by mitigating cognitive impairment independently of amyloid plaques. Elucidating this protective mechanism in AD could lead to new targets for early intervention.
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Affiliation(s)
- Osama Chaudry
- Department of Biological Sciences, Hunter College CUNY, New York, NY, USA
| | - Kelechi Ndukwe
- Department of Biological Sciences, Hunter College CUNY, New York, NY, USA
- PhD Program in Neuroscience, The Graduate Center CUNY, New York, NY, USA
| | - Lei Xie
- Department of Computer Sciences, Hunter College CUNY, New York, NY, USA
| | | | - Peter Serrano
- Department of Psychology, Hunter College CUNY, New York, NY, USA
| | - Patricia Rockwell
- Department of Biological Sciences, Hunter College CUNY, New York, NY, USA.
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6
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McLane VD, Lark ARS, Nass SR, Knapp PE, Hauser KF. HIV-1 Tat reduces apical dendritic spine density throughout the trisynaptic pathway in the hippocampus of male transgenic mice. Neurosci Lett 2022; 782:136688. [PMID: 35595189 DOI: 10.1016/j.neulet.2022.136688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 05/10/2022] [Accepted: 05/16/2022] [Indexed: 12/01/2022]
Abstract
Nearly one-third of persons infected with HIV-1 (PWH) develop HIV-associated neurocognitive disorders (HAND), which can be exacerbated by exposure to opioids. The impact of opioids on HIV-induced alterations in neuronal plasticity is less well understood. Both morphine exposure and HIV have been shown to disrupt synaptic growth and stability in the hippocampus suggesting a potential site of convergence for their deleterious effects. In the present study, we examined the density of dendritic spines in CA1 and CA3 pyramidal neurons, and granule neurons within the dentate gyrus representing the hippocampal trisynaptic pathway after short-term exposure to the HIV transactivator of transcription (Tat) protein and morphine. We exposed inducible male, HIV-1 Tat transgenic mice to escalating doses of morphine (10-40 mg/kg, b.i.d.) and examined synaptodendritic structure in Golgi-impregnated hippocampal neurons. HIV-1 Tat, but not morphine, systematically reduced the density of apical, but not basilar, dendrites of CA1 and CA3 pyramidal neurons, and granule neuronal apical dendrites, suggesting the coordinated loss of specific synaptic interconnections throughout the hippocampal trisynaptic pathway.
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Affiliation(s)
- Virginia D McLane
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA, USA
| | - Arianna R S Lark
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA, USA.
| | - Sara R Nass
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA, USA.
| | - Pamela E Knapp
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA, USA; Department of Anatomy & Neurobiology, Virginia Commonwealth University, Richmond, VA, USA; Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA, USA.
| | - Kurt F Hauser
- Department of Pharmacology & Toxicology, Virginia Commonwealth University, Richmond, VA, USA; Department of Anatomy & Neurobiology, Virginia Commonwealth University, Richmond, VA, USA; Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA, USA.
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7
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Analysis of the Effect of Neuroprotectors That Reduce the Level of Degeneration of Neurons in the Rat Hippocampus Caused by Administration of Beta-Amyloid Peptide Aβ 25-35. Bull Exp Biol Med 2022; 172:441-446. [PMID: 35175471 DOI: 10.1007/s10517-022-05410-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Indexed: 10/19/2022]
Abstract
Deposition of beta-amyloid peptide in the brain observed in Alzheimer's disease contributes to the development of cognitive deficits. We studied the abilities of different neuroprotectors to prevent or reduce degeneration of hippocampal neurons in rat brain 14 and 45 days after single intrahippocampal injection of beta-amyloid peptide 25-35 (Aβ25-35). Cytological analysis of the neurons of the hippocampal CA1 and CA3 fields showed predominant damage to CA1 neurons in 14 days and CA3 neurons in 45 days after Aβ25-35 administration. Single preliminary administrations of neuroprotectors fullerene C60FWS (antioxidant), neuromedin (nonselective inhibitor of acetylcholinesterase), and AM404 (activator of the endocannabinoid system) largely prevented neurodegeneration of neurons. Fullerene produced the most pronounced protective effect, which can be explained by its ability to prevent aggregation of proteins and destroy Aβ25-35 fibrils. The combined use of these neuroprotectors can provide the basis for the development of new approaches to prevention and treatment of Alzheimer's disease.
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8
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Xu L, Zhou Y, Hu L, Jiang H, Dong Y, Shen H, Lou Z, Yang S, Ji Y, Ruan L, Zhang X. Deficits in N-Methyl-D-Aspartate Receptor Function and Synaptic Plasticity in Hippocampal CA1 in APP/PS1 Mouse Model of Alzheimer's Disease. Front Aging Neurosci 2021; 13:772980. [PMID: 34916926 PMCID: PMC8669806 DOI: 10.3389/fnagi.2021.772980] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 10/29/2021] [Indexed: 12/24/2022] Open
Abstract
The N-methyl-D-aspartate receptor is a critical molecule for synaptic plasticity and cognitive function. Impaired synaptic plasticity is thought to contribute to the cognitive impairment associated with Alzheimer’s disease (AD). However, the neuropathophysiological alterations of N-methyl-D-aspartate receptor (NMDAR) function and synaptic plasticity in hippocampal CA1 in transgenic rodent models of AD are still unclear. In the present study, APP/PS1 mice were utilized as a transgenic model of AD, which exhibited progressive cognitive impairment including defective working memory, recognition memory, and spatial memory starting at 6 months of age and more severe by 8 months of age. We found an impaired long-term potentiation (LTP) and reduced NMDAR-mediated spontaneous excitatory postsynaptic currents (sEPSCs) in the hippocampal CA1 of APP/PS1 mice with 8 months of age. Golgi staining revealed that dendrites of pyramidal neurons had shorter length, fewer intersections, and lower spine density in APP/PS1 mice compared to control mice. Further, the reduced expression levels of NMDAR subunits, PSD95 and SNAP25 were observed in the hippocampus of APP/PS1 mice. These results suggest that NMDAR dysfunction, impaired synaptic plasticity, and disrupted neuronal morphology constitute an important part of the neuropathophysiological alterations associated with cognitive impairment in APP/PS1 mice.
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Affiliation(s)
- Le Xu
- Zhejiang Key Laboratory of Pathophysiology, Department of Pharmacology, School of Medicine, Ningbo University, Ningbo, China.,Department of Psychosomatic Medicine, Ningbo First Hospital, Ningbo Hospital of Zhejiang University, Ningbo, China
| | - Yiying Zhou
- Zhejiang Key Laboratory of Pathophysiology, Department of Pharmacology, School of Medicine, Ningbo University, Ningbo, China.,Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, China
| | - Linbo Hu
- Zhejiang Key Laboratory of Pathophysiology, Department of Pharmacology, School of Medicine, Ningbo University, Ningbo, China
| | - Hongde Jiang
- Zhejiang Key Laboratory of Pathophysiology, Department of Pharmacology, School of Medicine, Ningbo University, Ningbo, China
| | - Yibei Dong
- Zhejiang Key Laboratory of Pathophysiology, Department of Pharmacology, School of Medicine, Ningbo University, Ningbo, China
| | - Haowei Shen
- Zhejiang Key Laboratory of Pathophysiology, Department of Pharmacology, School of Medicine, Ningbo University, Ningbo, China.,Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, China
| | - Zhongze Lou
- Department of Psychosomatic Medicine, Ningbo First Hospital, Ningbo Hospital of Zhejiang University, Ningbo, China.,Central Laboratory of the Medical Research Center, Ningbo First Hospital, Ningbo Hospital of Zhejiang University, Ningbo, China
| | - Siyu Yang
- Zhejiang Key Laboratory of Pathophysiology, Department of Pharmacology, School of Medicine, Ningbo University, Ningbo, China
| | - Yunxin Ji
- Department of Psychosomatic Medicine, Ningbo First Hospital, Ningbo Hospital of Zhejiang University, Ningbo, China
| | - Liemin Ruan
- Department of Psychosomatic Medicine, Ningbo First Hospital, Ningbo Hospital of Zhejiang University, Ningbo, China
| | - Xiaoqin Zhang
- Zhejiang Key Laboratory of Pathophysiology, Department of Pharmacology, School of Medicine, Ningbo University, Ningbo, China.,Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, China
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Ramadan WS, Alkarim S. Ellagic Acid Modulates the Amyloid Precursor Protein Gene via Superoxide Dismutase Regulation in the Entorhinal Cortex in an Experimental Alzheimer's Model. Cells 2021; 10:3511. [PMID: 34944019 PMCID: PMC8700605 DOI: 10.3390/cells10123511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/04/2021] [Accepted: 12/08/2021] [Indexed: 12/12/2022] Open
Abstract
Patients suffering from Alzheimer's disease (AD) are still increasing worldwide. The development of (AD) is related to oxidative stress and genetic factors. This study investigated the therapeutic effects of ellagic acid (EA) on the entorhinal cortex (ERC), which plays a major role in episodic memory, in the brains of an AD rat model. AD was induced using AlCl3 (50 mg/kg orally for 4 weeks). Rats were divided into four groups: control, AD model, EA (treated with 50 mg/kg EA orally for 4 weeks), and ADEA (AD rats treated with EA after AlCl3 was stopped) groups. All rats were investigated for episodic memory using the novel object recognition test (NORT), antioxidant serum biomarkers, lipid peroxidation, histopathology of the ERC, and quantitative PCR for the superoxide dismutase (SOD) gene. EA therapy in AD rats significantly increased the discrimination index for NORT and the levels of SOD, glutathione, and total antioxidant capacity. Lipid peroxidation products were decreased, and the neurofibrillary tangles and neuritic plaques in the ERC sections were reduced after EA administration. The decrease in ERC thickness in the AD group, caused by caspase-3-mediated apoptosis and neurotoxicity due to amyloid precursor protein, was modulated by the increased SOD mRNA expression. Adjustment of the ERC antioxidant environment and decreased oxidative stress under EA administration enhanced SOD expression, resulting in the modulation of amyloid precursor protein toxicity and caspase-3-mediated apoptosis, thereby restoring episodic memory.
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Affiliation(s)
- Wafaa S. Ramadan
- Department of Anatomy, Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Saleh Alkarim
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
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10
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Alfaro-Ruiz R, Martín-Belmonte A, Aguado C, Hernández F, Moreno-Martínez AE, Ávila J, Luján R. The Expression and Localisation of G-Protein-Coupled Inwardly Rectifying Potassium (GIRK) Channels Is Differentially Altered in the Hippocampus of Two Mouse Models of Alzheimer's Disease. Int J Mol Sci 2021; 22:ijms222011106. [PMID: 34681766 PMCID: PMC8541655 DOI: 10.3390/ijms222011106] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 12/31/2022] Open
Abstract
G protein-gated inwardly rectifying K+ (GIRK) channels are the main targets controlling excitability and synaptic plasticity on hippocampal neurons. Consequently, dysfunction of GIRK-mediated signalling has been implicated in the pathophysiology of Alzheimer´s disease (AD). Here, we provide a quantitative description on the expression and localisation patterns of GIRK2 in two transgenic mice models of AD (P301S and APP/PS1 mice), combining histoblots and immunoelectron microscopic approaches. The histoblot technique revealed differences in the expression of GIRK2 in the two transgenic mice models. The expression of GIRK2 was significantly reduced in the hippocampus of P301S mice in a laminar-specific manner at 10 months of age but was unaltered in APP/PS1 mice at 12 months compared to age-matched wild type mice. Ultrastructural approaches using the pre-embedding immunogold technique, demonstrated that the subcellular localisation of GIRK2 was significantly reduced along the neuronal surface of CA1 pyramidal cells, but increased in its frequency at cytoplasmic sites, in both P301S and APP/PS1 mice. We also found a decrease in plasma membrane GIRK2 channels in axon terminals contacting dendritic spines of CA1 pyramidal cells in P301S and APP/PS1 mice. These data demonstrate for the first time a redistribution of GIRK channels from the plasma membrane to intracellular sites in different compartments of CA1 pyramidal cells. Altogether, the pre- and post-synaptic reduction of GIRK2 channels suggest that GIRK-mediated alteration of the excitability in pyramidal cells could contribute to the cognitive dysfunctions as described in the two AD animal models.
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Affiliation(s)
- Rocío Alfaro-Ruiz
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/Almansa 14, 02008 Albacete, Spain; (R.A.-R.); (A.M.-B.); (C.A.); (A.E.M.-M.)
| | - Alejandro Martín-Belmonte
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/Almansa 14, 02008 Albacete, Spain; (R.A.-R.); (A.M.-B.); (C.A.); (A.E.M.-M.)
| | - Carolina Aguado
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/Almansa 14, 02008 Albacete, Spain; (R.A.-R.); (A.M.-B.); (C.A.); (A.E.M.-M.)
| | - Félix Hernández
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, ISCIII, 28049 Madrid, Spain; (F.H.); (J.Á.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, 28049 Madrid, Spain
| | - Ana Esther Moreno-Martínez
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/Almansa 14, 02008 Albacete, Spain; (R.A.-R.); (A.M.-B.); (C.A.); (A.E.M.-M.)
| | - Jesús Ávila
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, ISCIII, 28049 Madrid, Spain; (F.H.); (J.Á.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, 28049 Madrid, Spain
| | - Rafael Luján
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/Almansa 14, 02008 Albacete, Spain; (R.A.-R.); (A.M.-B.); (C.A.); (A.E.M.-M.)
- Correspondence: ; Tel.: +34-967-599200 (ext. 2196)
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11
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Somatostatin and Astroglial Involvement in the Human Limbic System in Alzheimer's Disease. Int J Mol Sci 2021; 22:ijms22168434. [PMID: 34445147 PMCID: PMC8395127 DOI: 10.3390/ijms22168434] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 07/28/2021] [Accepted: 08/04/2021] [Indexed: 11/16/2022] Open
Abstract
Alzheimer's disease (AD) is the most prevalent neurodegenerative disease in the elderly. Progressive accumulation of insoluble isoforms of amyloid-β peptide (Aβ) and tau protein are the major neuropathologic hallmarks, and the loss of cholinergic pathways underlies cognitive deficits in patients. Recently, glial involvement has gained interest regarding its effect on preservation and impairment of brain integrity. The limbic system, including temporal lobe regions and the olfactory bulb, is particularly affected in the early stages. In the early 1980s, the reduced expression of the somatostatin neuropeptide was described in AD. However, over the last three decades, research on somatostatin in Alzheimer's disease has been scarce in humans. Therefore, the aim of this study was to stereologically quantify the expression of somatostatin in the human hippocampus and olfactory bulb and analyze its spatial distribution with respect to that of Aβ and au neuropathologic proteins and astroglia. The results indicate that somatostatin-expressing cells are reduced by 50% in the hippocampus but are preserved in the olfactory bulb. Interestingly, the coexpression of somatostatin with the Aβ peptide is very common but not with the tau protein. Finally, the coexpression of somatostatin with astrocytes is rare, although their spatial distribution is very similar. Altogether, we can conclude that somatostatin expression is highly reduced in the human hippocampus, but not the olfactory bulb, and may play a role in Alzheimer's disease pathogenesis.
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12
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The Density of Group I mGlu 5 Receptors Is Reduced along the Neuronal Surface of Hippocampal Cells in a Mouse Model of Alzheimer's Disease. Int J Mol Sci 2021; 22:ijms22115867. [PMID: 34070808 PMCID: PMC8199018 DOI: 10.3390/ijms22115867] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/21/2021] [Accepted: 05/26/2021] [Indexed: 11/17/2022] Open
Abstract
Metabotropic glutamate receptor subtype 5 (mGlu5) is implicated in the pathophysiology of Alzheimer’s disease (AD). However, its alteration at the subcellular level in neurons is still unexplored. Here, we provide a quantitative description on the expression and localisation patterns of mGlu5 in the APP/PS1 model of AD at 12 months of age, combining immunoblots, histoblots and high-resolution immunoelectron microscopic approaches. Immunoblots revealed that the total amount of mGlu5 protein in the hippocampus, in addition to downstream molecules, i.e., Gq/11 and PLCβ1, was similar in both APP/PS1 mice and age-matched wild type mice. Histoblots revealed that mGlu5 expression in the brain and its laminar expression in the hippocampus was also unaltered. However, the ultrastructural techniques of SDS-FRL and pre-embedding immunogold demonstrated that the subcellular localisation of mGlu5 was significantly reduced along the neuronal surface of hippocampal principal cells, including CA1 pyramidal cells and DG granule cells, in APP/PS1 mice at 12 months of age. The decrease in the surface localisation of mGlu5 was accompanied by an increase in its frequency at intracellular sites in the two neuronal populations. Together, these data demonstrate, for the first time, a loss of mGlu5 at the plasma membrane and accumulation at intracellular sites in different principal cells of the hippocampus in APP/PS1 mice, suggesting an alteration of the excitability and synaptic transmission that could contribute to the cognitive dysfunctions in this AD animal model. Further studies are required to elucidate the specificity of mGlu5-associated molecules and downstream signalling pathways in the progression of the pathology.
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13
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Domínguez-Álvaro M, Montero-Crespo M, Blazquez-Llorca L, Plaza-Alonso S, Cano-Astorga N, DeFelipe J, Alonso-Nanclares L. 3D Analysis of the Synaptic Organization in the Entorhinal Cortex in Alzheimer's Disease. eNeuro 2021; 8:ENEURO.0504-20.2021. [PMID: 34039651 PMCID: PMC8225407 DOI: 10.1523/eneuro.0504-20.2021] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 03/26/2021] [Accepted: 04/16/2021] [Indexed: 01/01/2023] Open
Abstract
The entorhinal cortex (EC) is especially vulnerable in the early stages of Alzheimer's disease (AD). In particular, cognitive deficits have been linked to alterations in the upper layers of EC. In the present report, we examined Layers II and III from eight human brain autopsies (four subjects with no recorded neurologic alterations and four AD cases). We used stereological methods to assess cortical atrophy of the EC and possible changes in the volume occupied by different cortical elements (neuronal and glial cell bodies; blood vessels; and neuropil). We performed 3D ultrastructural analyses of synapses using focused ion beam/scanning electron microscopy (FIB/SEM) to examine possible alterations related to AD. At the light microscope level, we found a significantly lower volume fraction occupied by neuronal bodies in Layer III and a higher volume fraction occupied by glial cell bodies in Layer II in AD cases. At the ultrastructural level, we observed that (1) there was a significantly lower synaptic density in both layers in AD cases; (2) synapses were larger and more complex in Layer II in AD cases; and (3) there was a greater proportion of small and simple synapses in Layer III in AD cases than in control individuals. These structural differences may play a role in the anatomic basis for the impairment of cognitive functions in AD.
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Affiliation(s)
- M Domínguez-Álvaro
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid 28223, Spain
| | - M Montero-Crespo
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid 28223, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid 28002, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III 28031, Madrid, Spain
| | - L Blazquez-Llorca
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid 28223, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III 28031, Madrid, Spain
- Sección Departamental de Anatomía y Embriología (Veterinaria), Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid 28040, Spain
| | - S Plaza-Alonso
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid 28223, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid 28002, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III 28031, Madrid, Spain
| | - N Cano-Astorga
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid 28223, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid 28002, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III 28031, Madrid, Spain
| | - J DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid 28223, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid 28002, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III 28031, Madrid, Spain
| | - L Alonso-Nanclares
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid 28223, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid 28002, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III 28031, Madrid, Spain
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14
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Hanna R, Flamier A, Barabino A, Bernier G. G-quadruplexes originating from evolutionary conserved L1 elements interfere with neuronal gene expression in Alzheimer's disease. Nat Commun 2021; 12:1828. [PMID: 33758195 PMCID: PMC7987966 DOI: 10.1038/s41467-021-22129-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 03/03/2021] [Indexed: 02/06/2023] Open
Abstract
DNA sequences containing consecutive guanines organized in 4-interspaced tandem repeats can form stable single-stranded secondary structures, called G-quadruplexes (G4). Herein, we report that the Polycomb group protein BMI1 is enriched at heterochromatin regions containing putative G4 DNA sequences, and that G4 structures accumulate in cells with reduced BMI1 expression and/or relaxed chromatin, including sporadic Alzheimer's disease (AD) neurons. In AD neurons, G4 structures preferentially accumulate in lamina-associated domains, and this is rescued by re-establishing chromatin compaction. ChIP-seq analyses reveal that G4 peaks correspond to evolutionary conserved Long Interspersed Element-1 (L1) sequences predicted to be transcriptionally active. Hence, G4 structures co-localize with RNAPII, and inhibition of transcription can reverse the G4 phenotype without affecting chromatin's state, thus uncoupling both components. Intragenic G4 structures affecting splicing events are furthermore associated with reduced neuronal gene expression in AD. Active L1 sequences are thus at the origin of most G4 structures observed in human neurons.
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Affiliation(s)
- Roy Hanna
- Stem Cell and Developmental Biology Laboratory, Hôpital Maisonneuve-Rosemont, Montreal, QC, Canada
| | - Anthony Flamier
- Stem Cell and Developmental Biology Laboratory, Hôpital Maisonneuve-Rosemont, Montreal, QC, Canada
- Whitehead Institute of Biomedical Research, Cambridge, MA, USA
| | - Andrea Barabino
- Stem Cell and Developmental Biology Laboratory, Hôpital Maisonneuve-Rosemont, Montreal, QC, Canada
| | - Gilbert Bernier
- Stem Cell and Developmental Biology Laboratory, Hôpital Maisonneuve-Rosemont, Montreal, QC, Canada.
- Department of Neurosciences, University of Montreal, Montreal, QC, Canada.
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15
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Amani M, Lauterborn JC, Le AA, Cox BM, Wang W, Quintanilla J, Cox CD, Gall CM, Lynch G. Rapid Aging in the Perforant Path Projections to the Rodent Dentate Gyrus. J Neurosci 2021; 41:2301-2312. [PMID: 33514675 PMCID: PMC8018768 DOI: 10.1523/jneurosci.2376-20.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 01/04/2021] [Accepted: 01/16/2021] [Indexed: 12/15/2022] Open
Abstract
Why layers II/III of entorhinal cortex (EC) deteriorate in advance of other regions during the earliest stages of Alzheimer's disease is poorly understood. Failure of retrograde trophic support from synapses to cell bodies is a common cause of neuronal atrophy, and we accordingly tested for early-life deterioration in projections of rodent layer II EC neurons. Using electrophysiology and quantitative imaging, changes in EC terminals during young adulthood were evaluated in male rats and mice. Field excitatory postsynaptic potentials, input/output curves, and frequency following capacity by lateral perforant path (LPP) projections from lateral EC to dentate gyrus were unchanged from 3 to 8-10 months of age. In contrast, the unusual presynaptic form of long-term potentiation (LTP) expressed by the LPP was profoundly impaired by 8 months in rats and mice. This impairment was accompanied by a reduction in the spine to terminal endocannabinoid signaling needed for LPP-LTP induction and was offset by an agent that enhances signaling. There was a pronounced age-related increase in synaptophysin within LPP terminals, an effect suggestive of incipient pathology. Relatedly, presynaptic levels of TrkB-receptors mediating retrograde trophic signaling-were reduced in the LPP terminal field. LTP and TrkB content were also reduced in the medial perforant path of 8- to 10-month-old rats. As predicted, performance on an LPP-dependent episodic memory task declined by late adulthood. We propose that memory-related synaptic plasticity in EC projections is unusually sensitive to aging, which predisposes EC neurons to pathogenesis later in life.SIGNIFICANCE STATEMENT Neurons within human superficial entorhinal cortex are particularly vulnerable to effects of aging and Alzheimer's disease, although why this is the case is not understood. Here we report that perforant path projections from layer II entorhinal cortex to the dentate gyrus exhibit rapid aging in rodents, including reduced synaptic plasticity and abnormal protein content by 8-10 months of age. Moreover, there was a substantial decline in the performance of an episodic memory task that depends on entorhinal cortical projections at the same ages. Overall, the results suggest that the loss of plasticity and related trophic signaling predispose the entorhinal neurons to functional decline in relatively young adulthood.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Gary Lynch
- Departments of Anatomy & Neurobiology
- Psychiatry & Human Behavior, University of California, Irvine, Irvine, California 92697
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16
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Nuñez A, Buño W. The Theta Rhythm of the Hippocampus: From Neuronal and Circuit Mechanisms to Behavior. Front Cell Neurosci 2021; 15:649262. [PMID: 33746716 PMCID: PMC7970048 DOI: 10.3389/fncel.2021.649262] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 01/28/2021] [Indexed: 11/17/2022] Open
Abstract
This review focuses on the neuronal and circuit mechanisms involved in the generation of the theta (θ) rhythm and of its participation in behavior. Data have accumulated indicating that θ arises from interactions between medial septum-diagonal band of Broca (MS-DbB) and intra-hippocampal circuits. The intrinsic properties of MS-DbB and hippocampal neurons have also been shown to play a key role in θ generation. A growing number of studies suggest that θ may represent a timing mechanism to temporally organize movement sequences, memory encoding, or planned trajectories for spatial navigation. To accomplish those functions, θ and gamma (γ) oscillations interact during the awake state and REM sleep, which are considered to be critical for learning and memory processes. Further, we discuss that the loss of this interaction is at the base of various neurophatological conditions.
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Affiliation(s)
- Angel Nuñez
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autonoma de Madrid, Madrid, Spain
| | - Washington Buño
- Instituto Cajal, Consejo Superior de Investigaciones Cientificas, Madrid, Spain
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17
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Montero-Crespo M, Domínguez-Álvaro M, Alonso-Nanclares L, DeFelipe J, Blazquez-Llorca L. Three-dimensional analysis of synaptic organization in the hippocampal CA1 field in Alzheimer's disease. Brain 2021; 144:553-573. [PMID: 33324984 PMCID: PMC8240746 DOI: 10.1093/brain/awaa406] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 09/07/2020] [Accepted: 09/20/2020] [Indexed: 02/06/2023] Open
Abstract
Alzheimer's disease is the most common form of dementia, characterized by a persistent and progressive impairment of cognitive functions. Alzheimer's disease is typically associated with extracellular deposits of amyloid-β peptide and accumulation of abnormally phosphorylated tau protein inside neurons (amyloid-β and neurofibrillary pathologies). It has been proposed that these pathologies cause neuronal degeneration and synaptic alterations, which are thought to constitute the major neurobiological basis of cognitive dysfunction in Alzheimer's disease. The hippocampal formation is especially vulnerable in the early stages of Alzheimer's disease. However, the vast majority of electron microscopy studies have been performed in animal models. In the present study, we performed an extensive 3D study of the neuropil to investigate the synaptic organization in the stratum pyramidale and radiatum in the CA1 field of Alzheimer's disease cases with different stages of the disease, using focused ion beam/scanning electron microscopy (FIB/SEM). In cases with early stages of Alzheimer's disease, the synapse morphology looks normal and we observed no significant differences between control and Alzheimer's disease cases regarding the synaptic density, the ratio of excitatory and inhibitory synapses, or the spatial distribution of synapses. However, differences in the distribution of postsynaptic targets and synaptic shapes were found. Furthermore, a lower proportion of larger excitatory synapses in both strata were found in Alzheimer's disease cases. Individuals in late stages of the disease suffered the most severe synaptic alterations, including a decrease in synaptic density and morphological alterations of the remaining synapses. Since Alzheimer's disease cases show cortical atrophy, our data indicate a reduction in the total number (but not the density) of synapses at early stages of the disease, with this reduction being much more accentuated in subjects with late stages of Alzheimer's disease. The observed synaptic alterations may represent a structural basis for the progressive learning and memory dysfunctions seen in Alzheimer's disease cases.
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Affiliation(s)
- Marta Montero-Crespo
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Av. Doctor Arce, 37, 28002 Madrid, Spain
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Pozuelo de Alarcón, Madrid, Spain
| | - Marta Domínguez-Álvaro
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Pozuelo de Alarcón, Madrid, Spain
| | - Lidia Alonso-Nanclares
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Av. Doctor Arce, 37, 28002 Madrid, Spain
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Pozuelo de Alarcón, Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, c/Valderrebollo, 5, 28031 Madrid, Spain
| | - Javier DeFelipe
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Av. Doctor Arce, 37, 28002 Madrid, Spain
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Pozuelo de Alarcón, Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, c/Valderrebollo, 5, 28031 Madrid, Spain
| | - Lidia Blazquez-Llorca
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Pozuelo de Alarcón, Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, c/Valderrebollo, 5, 28031 Madrid, Spain
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), c/Juan del Rosal, 10, 28040 Madrid, Spain
- Sección Departamental de Anatomía y Embriología (Veterinaria), Facultad de Veterinaria, Universidad Complutense de Madrid, Av. Puerta de Hierro, s/n, 28040 Madrid, Spain
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18
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Garad M, Edelmann E, Leßmann V. Impairment of Spike-Timing-Dependent Plasticity at Schaffer Collateral-CA1 Synapses in Adult APP/PS1 Mice Depends on Proximity of Aβ Plaques. Int J Mol Sci 2021; 22:1378. [PMID: 33573114 PMCID: PMC7866519 DOI: 10.3390/ijms22031378] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/24/2021] [Accepted: 01/25/2021] [Indexed: 12/16/2022] Open
Abstract
Alzheimer's disease (AD) is a multifaceted neurodegenerative disorder characterized by progressive and irreversible cognitive decline, with no disease-modifying therapy until today. Spike timing-dependent plasticity (STDP) is a Hebbian form of synaptic plasticity, and a strong candidate to underlie learning and memory at the single neuron level. Although several studies reported impaired long-term potentiation (LTP) in the hippocampus in AD mouse models, the impact of amyloid-β (Aβ) pathology on STDP in the hippocampus is not known. Using whole cell patch clamp recordings in CA1 pyramidal neurons of acute transversal hippocampal slices, we investigated timing-dependent (t-) LTP induced by STDP paradigms at Schaffer collateral (SC)-CA1 synapses in slices of 6-month-old adult APP/PS1 AD model mice. Our results show that t-LTP can be induced even in fully developed adult mice with different and even low repeat STDP paradigms. Further, adult APP/PS1 mice displayed intact t-LTP induced by 1 presynaptic EPSP paired with 4 postsynaptic APs (6× 1:4) or 1 presynaptic EPSP paired with 1 postsynaptic AP (100× 1:1) STDP paradigms when the position of Aβ plaques relative to recorded CA1 neurons in the slice were not considered. However, when Aβ plaques were live stained with the fluorescent dye methoxy-X04, we observed that in CA1 neurons with their somata <200 µm away from the border of the nearest Aβ plaque, t-LTP induced by 6× 1:4 stimulation was significantly impaired, while t-LTP was unaltered in CA1 neurons >200 µm away from plaques. Treatment of APP/PS1 mice with the anti-inflammatory drug fingolimod that we previously showed to alleviate synaptic deficits in this AD mouse model did not rescue the impaired t-LTP. Our data reveal that overexpression of APP and PS1 mutations in AD model mice disrupts t-LTP in an Aβ plaque distance-dependent manner, but cannot be improved by fingolimod (FTY720) that has been shown to rescue conventional LTP in CA1 of APP/PS1 mice.
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Affiliation(s)
- Machhindra Garad
- Institute of Physiology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany; (M.G.); (E.E.)
| | - Elke Edelmann
- Institute of Physiology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany; (M.G.); (E.E.)
- Center for Behavioral Brain Sciences (CBBS), 39120 Magdeburg, Germany
| | - Volkmar Leßmann
- Institute of Physiology, Medical Faculty, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany; (M.G.); (E.E.)
- Center for Behavioral Brain Sciences (CBBS), 39120 Magdeburg, Germany
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19
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Olajide OJ, Suvanto ME, Chapman CA. Molecular mechanisms of neurodegeneration in the entorhinal cortex that underlie its selective vulnerability during the pathogenesis of Alzheimer's disease. Biol Open 2021; 10:bio056796. [PMID: 33495355 PMCID: PMC7860115 DOI: 10.1242/bio.056796] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The entorhinal cortex (EC) is a vital component of the medial temporal lobe, and its contributions to cognitive processes and memory formation are supported through its extensive interconnections with the hippocampal formation. During the pathogenesis of Alzheimer's disease (AD), many of the earliest degenerative changes are seen within the EC. Neurodegeneration in the EC and hippocampus during AD has been clearly linked to impairments in memory and cognitive function, and a growing body of evidence indicates that molecular and functional neurodegeneration within the EC may play a primary role in cognitive decline in the early phases of AD. Defining the mechanisms underlying molecular neurodegeneration in the EC is crucial to determining its contributions to the pathogenesis of AD. Surprisingly few studies have focused on understanding the mechanisms of molecular neurodegeneration and selective vulnerability within the EC. However, there have been advancements indicating that early dysregulation of cellular and molecular signaling pathways in the EC involve neurodegenerative cascades including oxidative stress, neuroinflammation, glia activation, stress kinases activation, and neuronal loss. Dysfunction within the EC can impact the function of the hippocampus, which relies on entorhinal inputs, and further degeneration within the hippocampus can compound this effect, leading to severe cognitive disruption. This review assesses the molecular and cellular mechanisms underlying early degeneration in the EC during AD. These mechanisms may underlie the selective vulnerability of neuronal subpopulations in this brain region to the disease development and contribute both directly and indirectly to cognitive loss.This paper has an associated Future Leader to Watch interview with the first author of the article.
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Affiliation(s)
- Olayemi Joseph Olajide
- Division of Neurobiology, Department of Anatomy, University of Ilorin, Ilorin, Nigeria, PMB 1515
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, Québec, Canada H4B 1R6
| | - Marcus E Suvanto
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, Québec, Canada H4B 1R6
| | - Clifton Andrew Chapman
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, Québec, Canada H4B 1R6
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20
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Ammassari-Teule M. Early-Occurring Dendritic Spines Alterations in Mouse Models of Alzheimer's Disease Inform on Primary Causes of Neurodegeneration. Front Synaptic Neurosci 2020; 12:566615. [PMID: 33013348 PMCID: PMC7511703 DOI: 10.3389/fnsyn.2020.566615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/17/2020] [Indexed: 01/04/2023] Open
Abstract
The consensus that synaptic failure is the earliest cause of cognitive deterioration in Alzheimer’s disease (AD) has initially led to investigate structural (dendritic spines) and physiological (LTP) synaptic dysfunctions in mouse models of AD with established cognitive alterations. The challenge is now to track down ultra-early alterations in spines to uncover causes rather than disease’s symptoms. This review article pinpoints dysregulations of the postsynaptic density (PSD) protein network which alter the morphology and function of spines in pre- and early- symptomatic hAPP mouse models of AD, and, hence, inform on primary causes of neurodegeneration.
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Affiliation(s)
- Martine Ammassari-Teule
- Institute of Biochemistry and Cell Biology, CNR-National Research Council, Rome, Italy.,Laboratory of Psychobiology, IRCCS Santa Lucia Foundation, Rome, Italy
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21
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Kawahara N, Mizutani A, Matsubara S, Takeda Y, Kobayashi H. GSK-3β mediates the effects of HNF-1β overexpression in ovarian clear cell carcinoma. Exp Ther Med 2020; 20:122. [PMID: 33005248 PMCID: PMC7523276 DOI: 10.3892/etm.2020.9250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 02/13/2020] [Indexed: 12/13/2022] Open
Abstract
Deubiquitinase USP28 is a target gene of the transcription factor HNF1 homeobox β (HNF-1β), which promotes the survival of ovarian clear cell carcinoma (OCCC) cell lines. However, the pharmacological inhibition of HNF-1β can cause several adverse effects as it is abundantly expressed in numerous organ systems, including the kidney, liver, pancreas and digestive tract. Therefore, small interfering RNA (siRNA) screening was performed in the current study to identify other potential downstream targets of the HNF-1β-mediated pathway. The results revealed that glycogen synthase kinase-3β (GSK-3β) may be a potential downstream target affecting cell viability. To further clarify the effects of GSK-3β, two human OCCC cell lines, TOV-21G (HNF-1β overexpressing line) and ES2 (HNF-1β negative) were transfected with siRNA targeting GSK-3β or control vectors. Loss-of-function studies using RNAi-mediated gene silencing indicated that HNF-1β facilitated GSK-3β expression, resulting in the loss of phosphorylated nuclear factor-κB (p-NFκB) and the reduction of TOV-21G cell proliferation. The cell proliferation assay also revealed that GSK-3β inhibitors rescued the effects of HNF-1β silencing on cell viability in a dose-dependent manner. Furthermore, the GSK-3β inhibitor, AR-A014418, effectively inhibited tumor cell proliferation in a xenograft mouse model. In conclusion and to the best of our knowledge, the current study was the first to determine that GSK-3β is a target gene of HNF-1β. In addition, the results of the present study revealed the novel HNF-1β-GSK-3β-p-NFκB pathway, occurring in response to DNA damage. Targeting this pathway may therefore represent a putative, novel, anticancer strategy in patients with OCCC.
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Affiliation(s)
- Naoki Kawahara
- Department of Obstetrics and Gynecology, Nara Medical University, Kashihara, Nara 634-8522, Japan
| | - Ayano Mizutani
- Department of Obstetrics and Gynecology, Nara Medical University, Kashihara, Nara 634-8522, Japan
| | - Sho Matsubara
- Department of Obstetrics and Gynecology, Nara Medical University, Kashihara, Nara 634-8522, Japan
| | - Yoshinori Takeda
- Department of Obstetrics and Gynecology, Nara Medical University, Kashihara, Nara 634-8522, Japan
| | - Hiroshi Kobayashi
- Department of Obstetrics and Gynecology, Nara Medical University, Kashihara, Nara 634-8522, Japan
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22
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Density of GABA B Receptors Is Reduced in Granule Cells of the Hippocampus in a Mouse Model of Alzheimer's Disease. Int J Mol Sci 2020; 21:ijms21072459. [PMID: 32252271 PMCID: PMC7177735 DOI: 10.3390/ijms21072459] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/27/2020] [Accepted: 03/31/2020] [Indexed: 12/22/2022] Open
Abstract
Metabotropic γ-aminobutyric acid (GABAB) receptors contribute to the control of network activity and information processing in hippocampal circuits by regulating neuronal excitability and synaptic transmission. The dysfunction in the dentate gyrus (DG) has been implicated in Alzheimer´s disease (AD). Given the involvement of GABAB receptors in AD, to determine their subcellular localisation and possible alteration in granule cells of the DG in a mouse model of AD at 12 months of age, we used high-resolution immunoelectron microscopic analysis. Immunohistochemistry at the light microscopic level showed that the regional and cellular expression pattern of GABAB1 was similar in an AD model mouse expressing mutated human amyloid precursor protein and presenilin1 (APP/PS1) and in age-matched wild type mice. High-resolution immunoelectron microscopy revealed a distance-dependent gradient of immunolabelling for GABAB receptors, increasing from proximal to distal dendrites in both wild type and APP/PS1 mice. However, the overall density of GABAB receptors at the neuronal surface of these postsynaptic compartments of granule cells was significantly reduced in APP/PS1 mice. Parallel to this reduction in surface receptors, we found a significant increase in GABAB1 at cytoplasmic sites. GABAB receptors were also detected at presynaptic sites in the molecular layer of the DG. We also found a decrease in plasma membrane GABAB receptors in axon terminals contacting dendritic spines of granule cells, which was more pronounced in the outer than in the inner molecular layer. Altogether, our data showing post- and presynaptic reduction in surface GABAB receptors in the DG suggest the alteration of the GABAB-mediated modulation of excitability and synaptic transmission in granule cells, which may contribute to the cognitive dysfunctions in the APP/PS1 model of AD.
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23
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Fukawa A, Aizawa T, Yamakawa H, Eguchi Yairi I. Identifying Core Regions for Path Integration on Medial Entorhinal Cortex of Hippocampal Formation. Brain Sci 2020; 10:brainsci10010028. [PMID: 31948100 PMCID: PMC7016820 DOI: 10.3390/brainsci10010028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 12/31/2019] [Indexed: 12/31/2022] Open
Abstract
Path integration is one of the functions that support the self-localization ability of animals. Path integration outputs position information after an animal’s movement when initial-position and movement information is input. The core region responsible for this function has been identified as the medial entorhinal cortex (MEC), which is part of the hippocampal formation that constitutes the limbic system. However, a more specific core region has not yet been identified. This research aims to clarify the detailed structure at the cell-firing level in the core region responsible for path integration from fragmentarily accumulated experimental and theoretical findings by reviewing 77 papers. This research draws a novel diagram that describes the MEC, the hippocampus, and their surrounding regions by focusing on the MEC’s input/output (I/O) information. The diagram was created by summarizing the results of exhaustively scrutinizing the papers that are relative to the I/O relationship, the connection relationship, and cell position and firing pattern. From additional investigations, we show function information related to path integration, such as I/O information and the relationship between multiple functions. Furthermore, we constructed an algorithmic hypothesis on I/O information and path-integration calculation method from the diagram and the information of functions related to path integration. The algorithmic hypothesis is composed of regions related to path integration, the I/O relations between them, the calculation performed there, and the information representations (cell-firing pattern) in them. Results of examining the hypothesis confirmed that the core region responsible for path integration was either stellate cells in layer II or pyramidal cells in layer III of the MEC.
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Affiliation(s)
- Ayako Fukawa
- Graduate School of Science and Engineering, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan;
- Correspondence: ; Tel.: +81-3-3238-3300
| | - Takahiro Aizawa
- Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;
| | - Hiroshi Yamakawa
- The Whole Brain Architecture Initiative, a Specified Nonprofit Organization, Nishikoiwa 2-19-21, Edogawa-ku, Tokyo 133-0057, Japan;
- Dwango Co., Ltd., KABUKIZA TOWER, 4-12-15 Ginza, Chuo-ku, Tokyo 104-0061, Japan
| | - Ikuko Eguchi Yairi
- Graduate School of Science and Engineering, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan;
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24
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Pluta R, Ułamek-Kozioł M, Kocki J, Bogucki J, Januszewski S, Bogucka-Kocka A, Czuczwar SJ. Expression of the Tau Protein and Amyloid Protein Precursor Processing Genes in the CA3 Area of the Hippocampus in the Ischemic Model of Alzheimer's Disease in the Rat. Mol Neurobiol 2020; 57:1281-1290. [PMID: 31713815 PMCID: PMC7031177 DOI: 10.1007/s12035-019-01799-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 09/22/2019] [Indexed: 01/07/2023]
Abstract
Understanding the mechanisms underlying the selective susceptibility to ischemia of the CA3 region is very important to explain the neuropathology of memory loss after brain ischemia. We used a rat model to study changes in gene expression of the amyloid protein precursor and its cleaving enzymes and tau protein in the hippocampal CA3 sector, after transient 10-min global brain ischemia with survival times of 2, 7, and 30 days. The expression of the α-secretase gene was below control values at all times studied. But, the expression of the β-secretase gene was below the control values at 2-7 days after ischemia and the maximal increase in its expression was observed on day 30. Expression of the presenilin 1 gene was significantly elevated above the control values at 2-7 days after ischemia and decreased below the control values at day 30. Expression of the presenilin 2 gene showed an opposite trend to the expression of presenilin 1. Expression of the amyloid protein precursor gene after ischemia was at all times above the control values with a huge significant overexpression on day 7. Additionally, the expression of the tau protein gene was below the control values 2 days after ischemia, but the significant increase in its expression was observed on days 7-30. Data show that brain ischemia activates neuronal changes and death in the CA3 region of the hippocampus in a manner dependent on amyloid and tau protein, thus determining a new and important way to regulate the survival and/or death of ischemic neurons.
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Affiliation(s)
- Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5 Str, 02-106 Warsaw, Poland
| | - Marzena Ułamek-Kozioł
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5 Str, 02-106 Warsaw, Poland ,First Department of Neurology, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Janusz Kocki
- Department of Clinical Genetics, Medical University of Lublin, Lublin, Poland
| | - Jacek Bogucki
- Department of Clinical Genetics, Medical University of Lublin, Lublin, Poland
| | - Sławomir Januszewski
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5 Str, 02-106 Warsaw, Poland
| | - Anna Bogucka-Kocka
- Department of Biology and Genetics, Medical University of Lublin, Lublin, Poland
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25
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Furcila D, Domínguez-Álvaro M, DeFelipe J, Alonso-Nanclares L. Subregional Density of Neurons, Neurofibrillary Tangles and Amyloid Plaques in the Hippocampus of Patients With Alzheimer's Disease. Front Neuroanat 2019; 13:99. [PMID: 31920568 PMCID: PMC6930895 DOI: 10.3389/fnana.2019.00099] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 11/28/2019] [Indexed: 12/19/2022] Open
Abstract
A variety of anatomical alterations have been reported in the hippocampal formation of patients with Alzheimer's Disease (AD) and these alterations have been correlated with cognitive symptoms in the early stages of the disease. Major hallmarks in AD are the presence of paired helical filaments of tau protein (PHFTau) within neurons, also known as neurofibrillary tangles (NFTs), and aggregates of amyloid-β protein (Aβ) which form plaques in the extracellular space. Nevertheless, how the density of plaques and NFTs relate to the severity of cell loss and cognitive decline is not yet clear. The aim of the present study was to further examine the possible relationship of both Aβ plaques and NFTs with neuronal loss in several hippocampal fields (DG, CA3, CA1, and subiculum) of 11 demented AD patients. For this purpose, using stereological techniques, we compared neuronal densities (Nissl-stained, and immunoreactive neurons for NeuN) with: (i) numbers of neurons immunostained for two isoforms of PHFTau (PHFTau-AT8 and PHFTau-pS396); and (ii) number of Aβ plaques. We found that CA1 showed the highest number of NFTs and Aβ plaques, whereas DG and CA3 displayed the lowest number of these markers. Furthermore, AD patients showed a variable neuronal loss in CA1 due to tangle-related cell death, which seems to correlate with the presence of extracellular tangles.
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Affiliation(s)
- Diana Furcila
- Cajal Laboratory of Cortical Circuits, Centre for Biomedical Technology (CTB), Universidad Politécnica de Madrid, Madrid, Spain.,Network Biomedical Research Center on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Marta Domínguez-Álvaro
- Cajal Laboratory of Cortical Circuits, Centre for Biomedical Technology (CTB), Universidad Politécnica de Madrid, Madrid, Spain
| | - Javier DeFelipe
- Cajal Laboratory of Cortical Circuits, Centre for Biomedical Technology (CTB), Universidad Politécnica de Madrid, Madrid, Spain.,Network Biomedical Research Center on Neurodegenerative Diseases (CIBERNED), Madrid, Spain.,Cajal Institute (CSIC), Madrid, Spain
| | - Lidia Alonso-Nanclares
- Cajal Laboratory of Cortical Circuits, Centre for Biomedical Technology (CTB), Universidad Politécnica de Madrid, Madrid, Spain.,Network Biomedical Research Center on Neurodegenerative Diseases (CIBERNED), Madrid, Spain.,Cajal Institute (CSIC), Madrid, Spain
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26
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Martín-Belmonte A, Aguado C, Alfaro-Ruíz R, Moreno-Martínez AE, de la Ossa L, Martínez-Hernández J, Buisson A, Früh S, Bettler B, Shigemoto R, Fukazawa Y, Luján R. Reduction in the neuronal surface of post and presynaptic GABA B receptors in the hippocampus in a mouse model of Alzheimer's disease. Brain Pathol 2019; 30:554-575. [PMID: 31729777 PMCID: PMC7317930 DOI: 10.1111/bpa.12802] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 11/04/2019] [Indexed: 12/25/2022] Open
Abstract
The hippocampus plays key roles in learning and memory and is a main target of Alzheimer's disease (AD), which causes progressive memory impairments. Despite numerous investigations about the processes required for the normal hippocampal functions, the neurotransmitter receptors involved in the synaptic deficits by which AD disables the hippocampus are not yet characterized. By combining histoblots, western blots, immunohistochemistry and high-resolution immunoelectron microscopic methods for GABAB receptors, this study provides a quantitative description of the expression and the subcellular localization of GABAB1 in the hippocampus in a mouse model of AD at 1, 6 and 12 months of age. Western blots and histoblots showed that the total amount of protein and the laminar expression pattern of GABAB1 were similar in APP/PS1 mice and in age-matched wild-type mice. In contrast, immunoelectron microscopic techniques showed that the subcellular localization of GABAB1 subunit did not change significantly in APP/PS1 mice at 1 month of age, was significantly reduced in the stratum lacunosum-moleculare of CA1 pyramidal cells at 6 months of age and significantly reduced at the membrane surface of CA1 pyramidal cells at 12 months of age. This reduction of plasma membrane GABAB1 was paralleled by a significant increase of the subunit at the intracellular sites. We further observed a decrease of membrane-targeted GABAB receptors in axon terminals contacting CA1 pyramidal cells. Our data demonstrate compartment- and age-dependent reduction of plasma membrane-targeted GABAB receptors in the CA1 region of the hippocampus, suggesting that this decrease might be enough to alter the GABAB -mediated synaptic transmission taking place in AD.
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Affiliation(s)
- Alejandro Martín-Belmonte
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, 02008, Albacete, Spain
| | - Carolina Aguado
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, 02008, Albacete, Spain
| | - Rocío Alfaro-Ruíz
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, 02008, Albacete, Spain
| | - Ana Esther Moreno-Martínez
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, 02008, Albacete, Spain
| | - Luis de la Ossa
- Departamento de Sistemas Informáticos, Escuela Superior de Ingeniería Informática, Universidad de Castilla-La Mancha, 02071, Albacete, Spain
| | - José Martínez-Hernández
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, 02008, Albacete, Spain
| | - Alain Buisson
- Grenoble Institut des Neurosciences, Université Grenoble Alpes, BP 170, Grenoble, France
| | - Simon Früh
- Department of Biomedicine, Institute of Physiology, University of Basel, Basel, Switzerland
| | - Bernhard Bettler
- Department of Biomedicine, Institute of Physiology, University of Basel, Basel, Switzerland
| | - Ryuichi Shigemoto
- Institute of Science and Technology (IST Austria), Am Campus 1, A-3400, Klosterneuburg, Austria
| | - Yugo Fukazawa
- Division of Brain Structure and Function, Faculty of Medical Science, University of Fukui, Fukui, Japan.,Life Science Innovation Center, University of Fukui, Fukui, Japan.,Research Center for Child Mental Development, Faculty of Medical Science, University of Fukui, Fukui, Japan
| | - Rafael Luján
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, 02008, Albacete, Spain
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27
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Selesnick S, Piccinini G. Quantum-like behavior without quantum physics III : Logic and memory. J Biol Phys 2019; 45:335-366. [PMID: 31617032 DOI: 10.1007/s10867-019-09532-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Accepted: 08/28/2019] [Indexed: 01/13/2023] Open
Abstract
We employ some of the machinery developed in previous work to investigate the inferential and memory functions of quantum-like neural networks. We set up a logical apparatus to implement this in the form of a Gentzen sequent calculus which codifies some of the combinatory rules for the state spaces of the neuronal networks introduced earlier. We discuss memory storage in this context and along the way find formal proof that synchronicity promotes binding and storage. These results lead to an algorithmic fragment in calculus that simulates the memory function known as pattern completion. This claim is tested by noting that the failure of certain steps in the algorithm leads to memory deficits essentially identical to those found in such pathologies as Alzheimer's dementia, schizophrenia, and certain forms of autism. Moreover, a specific "power-of-two" wiring architecture and computational logic, which have been postulated and observed across many brain circuits, emerge spontaneously from our model. We draw conclusions concerning the possible nature of such mental processes qua computations.
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Affiliation(s)
- Stephen Selesnick
- Department of Mathematics and Computer Science, University of Missouri - St. Louis, St. Louis, MO, 63121, USA.
| | - Gualtiero Piccinini
- Department of Philosophy, Center for Neurodynamics, University of Missouri - St. Louis, St. Louis, MO, 63121, USA
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28
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3D Electron Microscopy Study of Synaptic Organization of the Normal Human Transentorhinal Cortex and Its Possible Alterations in Alzheimer's Disease. eNeuro 2019; 6:ENEURO.0140-19.2019. [PMID: 31217195 PMCID: PMC6620390 DOI: 10.1523/eneuro.0140-19.2019] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 05/23/2019] [Accepted: 05/27/2019] [Indexed: 01/10/2023] Open
Abstract
The transentorhinal cortex (TEC) is an obliquely oriented cortex located in the medial temporal lobe and, together with the entorhinal cortex, is one of the first affected areas in Alzheimer’s disease (AD). One of the most widely accepted hypotheses is that synaptopathy (synaptic alterations and loss) represents the major structural correlate of the cognitive decline observed in AD. However, very few electron microscope (EM) studies are available; the most common method to estimate synaptic density indirectly is by counting, at the light microscopic level, immunoreactive puncta using synaptic markers. To investigate synaptic morphology and possible alterations related to AD, a detailed three-dimensional (3D) ultrastructural analysis using focused ion beam/scanning EM (FIB/SEM) was performed in the neuropil of Layer II of the TEC in human brain samples from non-demented subjects and AD patients. Evaluation of the proportion and shape of asymmetric synapses (AS) and symmetric synapses (SS) targeting spines or dendritic shafts was performed using 3D reconstructions of every synapse. The 3D analysis of 4722 synapses revealed that the preferable targets were spine heads for AS and dendritic shafts for SS, both in control and AD cases. However, in AD patients, we observed a reduction in the percentage of synapses targeting spine heads. Regarding the shape of synapses, in both control cases and AD samples, the vast majority of synapses had a macular shape, followed by perforated or horseshoe-shaped synapses, with fragmented synapses being the least frequent type. Moreover, comparisons showed an increased number of fragmented AS in AD patients.
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Circuit-specific control of the medial entorhinal inputs to the dentate gyrus by atypical presynaptic NMDARs activated by astrocytes. Proc Natl Acad Sci U S A 2019; 116:13602-13610. [PMID: 31152131 PMCID: PMC6612919 DOI: 10.1073/pnas.1816013116] [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] [Indexed: 11/18/2022] Open
Abstract
Here, we investigated the properties of presynaptic N-methyl-d-aspartate receptors (pre-NMDARs) at corticohippocampal excitatory connections between perforant path (PP) afferents and dentate granule cells (GCs), a circuit involved in memory encoding and centrally affected in Alzheimer's disease and temporal lobe epilepsy. These receptors were previously reported to increase PP release probability in response to gliotransmitters released from astrocytes. Their activation occurred even under conditions of elevated Mg2+ and lack of action potential firing in the axons, although how this could be accomplished was unclear. We now report that these pre-NMDARs contain the GluN3a subunit conferring them low Mg2+ sensitivity. GluN3a-containing NMDARs at PP-GC synapses are preponderantly presynaptic vs. postsynaptic and persist beyond the developmental period. Moreover, they are expressed selectively at medial-not lateral-PP axons and act to functionally enhance release probability specifically of the medial perforant path (MPP) input to GC dendrites. By controlling release probability, GluN3a-containing pre-NMDARs also control the dynamic range for long-term potentiation (LTP) at MPP-GC synapses, an effect requiring Ca2+ signaling in astrocytes. Consistent with the functional observations, GluN3a subunits in MPP terminals are localized at sites away from the presynaptic release sites, often facing astrocytes, in line with a primary role for astrocytic inputs in their activation. Overall, GluN3A-containing pre-NMDARs emerge as atypical modulators of dendritic computations in the MPP-GC memory circuit.
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Computer Model of Synapse Loss During an Alzheimer's Disease-Like Pathology in Hippocampal Subregions DG, CA3 and CA1-The Way to Chaos and Information Transfer. ENTROPY 2019; 21:e21040408. [PMID: 33267122 PMCID: PMC7514896 DOI: 10.3390/e21040408] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 04/14/2019] [Accepted: 04/16/2019] [Indexed: 01/26/2023]
Abstract
The aim of the study was to compare the computer model of synaptic breakdown in an Alzheimer’s disease-like pathology in the dentate gyrus (DG), CA3 and CA1 regions of the hippocampus with a control model using neuronal parameters and methods describing the complexity of the system, such as the correlative dimension, Shannon entropy and positive maximal Lyapunov exponent. The model of synaptic breakdown (from 13% to 50%) in the hippocampus modeling the dynamics of an Alzheimer’s disease-like pathology was simulated. Modeling consisted in turning off one after the other EC2 connections and connections from the dentate gyrus on the CA3 pyramidal neurons. The pathological model of synaptic disintegration was compared to a control. The larger synaptic breakdown was associated with a statistically significant decrease in the number of spikes (R = −0.79, P < 0.001), spikes per burst (R = −0.76, P < 0.001) and burst duration (R = −0.83, P < 0.001) and an increase in the inter-burst interval (R = 0.85, P < 0.001) in DG-CA3-CA1. The positive maximal Lyapunov exponent in the control model was negative, but in the pathological model had a positive value of DG-CA3-CA1. A statistically significant decrease of Shannon entropy with the direction of information flow DG->CA3->CA1 (R = −0.79, P < 0.001) in the pathological model and a statistically significant increase with greater synaptic breakdown (R = 0.24, P < 0.05) of the CA3-CA1 region was obtained. The reduction of entropy transfer for DG->CA3 at the level of synaptic breakdown of 35% was 35%, compared with the control. Entropy transfer for CA3->CA1 at the level of synaptic breakdown of 35% increased to 95% relative to the control. The synaptic breakdown model in an Alzheimer’s disease-like pathology in DG-CA3-CA1 exhibits chaotic features as opposed to the control. Synaptic breakdown in which an increase of Shannon entropy is observed indicates an irreversible process of Alzheimer’s disease. The increase in synapse loss resulted in decreased information flow and entropy transfer in DG->CA3, and at the same time a strong increase in CA3->CA1.
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Joy T, Rao MS, Madhyastha S. N-Acetyl Cysteine Supplement Minimize Tau Expression and Neuronal Loss in Animal Model of Alzheimer's Disease. Brain Sci 2018; 8:E185. [PMID: 30314380 PMCID: PMC6210309 DOI: 10.3390/brainsci8100185] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 10/01/2018] [Accepted: 10/06/2018] [Indexed: 12/27/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of neurofibrillary tangles (NFT), deposition of beta amyloid plaques, and consequent neuronal loss in the brain tissue. Oxidative stress to the neurons is often attributed to AD, but its link to NFT and β-amyloid protein (BAP) still remains unclear. In an animal model of AD, we boosted the oxidative defense by N-Acetyl cysteine (NAC), a precursor of glutathione, a powerful antioxidant and free radical scavenger, to understand the link between oxidative stress and NFT. In mimicking AD, intracerebroventricular (ICV) colchicine, a microtubule disrupting agent also known to cause oxidative stress was administered to the rats. The animal groups consisted of an age-matched control, sham operated, AD, and NAC treated in AD models of rats. Cognitive function was evaluated in a passive avoidance test; neuronal degeneration was quantified using Nissl staining. NFT in the form of abnormal tau expression in different regions of the brain were evaluated through immunohistochemistry using rabbit anti-tau antibody. ICV has resulted in significant cognitive and neuronal loss in medial prefrontal cortex (MFC) and all the regions of the hippocampus. It has also resulted in increased accumulation of intraneuronal tau in the hippocampus and MFC. NAC treatment in AD model rats has reversed the cognitive loss and neuronal degeneration. The intraneuronal tau expression also minimized with NAC treatment in AD model rats. Thus, our findings suggest that an antioxidant supplement during the progression of AD is likely to prevent neuronal degeneration by minimizing the neurofibrillary degeneration in the form of tau accumulation.
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Affiliation(s)
- Teresa Joy
- Department of Anatomy, Kasturba Medical College, Mangalore 576104, India.
- Manipal Academy of Higher Education, Mangalore 576104, India.
| | - Muddanna S Rao
- Department of Anatomy, Faculty of Medicine, Kuwait University, Kuwait City 13110, Kuwait.
| | - Sampath Madhyastha
- Department of Anatomy, Faculty of Medicine, Kuwait University, Kuwait City 13110, Kuwait.
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Galloway CR, Ravipati K, Singh S, Lebois EP, Cohen RM, Levey AI, Manns JR. Hippocampal place cell dysfunction and the effects of muscarinic M 1 receptor agonism in a rat model of Alzheimer's disease. Hippocampus 2018; 28:568-585. [PMID: 29742799 DOI: 10.1002/hipo.22961] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 04/02/2018] [Accepted: 05/06/2018] [Indexed: 11/09/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease that disproportionately impacts memory and the hippocampus. However, it is unclear how AD pathology influences the activity of surviving neurons in the hippocampus to contribute to the memory symptoms in AD. One well-understood connection between spatial memory and neuronal activity in healthy brains is the activity of place cells, neurons in the hippocampus that fire preferentially in a specific location of a given environment (the place field of the place cell). In the present study, place cells were recorded from the hippocampus in a recently-developed rat model of AD (Tg-F344 AD) at an age (12-20 months) at which the AD rats showed marked spatial memory deficits. Place cells in the CA2 and CA3 pyramidal regions of the hippocampus in AD rats showed sharply reduced spatial fidelity relative to wild-type (WT) rats. In contrast, spiking activity of place cells recorded in region CA1 in AD rats showed good spatial fidelity that was similar to CA1 place cells in WT rats. Oral administration of the M1 muscarinic acetylcholine receptor agonist VU0364572 impacted place cell firing rates in CA1 and CA2/3 hippocampal regions, but did not improve the spatial fidelity of CA2/3 hippocampal place cells in AD rats. The results indicated that, to the extent the spatial memory impairment in AD rats was attributable to hippocampal dysfunction, the memory impairment was more attributable to dysfunction in hippocampal regions CA2 and CA3 rather than CA1.
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Affiliation(s)
| | - Kaushik Ravipati
- Neuroscience and Behavioral Biology Program, Emory University, Atlanta, Georgia
| | - Suyashi Singh
- Neuroscience and Behavioral Biology Program, Emory University, Atlanta, Georgia
| | - Evan P Lebois
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts
| | - Robert M Cohen
- Department of Psychiatry, Emory University, Atlanta, Georgia
| | - Allan I Levey
- Department of Neurology, Emory University, Atlanta, Georgia
| | - Joseph R Manns
- Department of Psychology, Emory University, Atlanta, Georgia
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Domínguez-Álvaro M, Montero-Crespo M, Blazquez-Llorca L, Insausti R, DeFelipe J, Alonso-Nanclares L. Three-dimensional analysis of synapses in the transentorhinal cortex of Alzheimer's disease patients. Acta Neuropathol Commun 2018; 6:20. [PMID: 29499755 PMCID: PMC5834884 DOI: 10.1186/s40478-018-0520-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 02/17/2018] [Indexed: 12/11/2022] Open
Abstract
Synaptic dysfunction or loss in early stages of Alzheimer’s disease (AD) is thought to be a major structural correlate of cognitive dysfunction. Early loss of episodic memory, which occurs at the early stage of AD, is closely associated with the progressive degeneration of medial temporal lobe (MTL) structures of which the transentorhinal cortex (TEC) is the first affected area. However, no ultrastructural studies have been performed in this region in human brain samples from AD patients. In the present study, we have performed a detailed three-dimensional (3D) ultrastructural analysis using focused ion beam/scanning electron microscopy (FIB/SEM) to investigate possible synaptic alterations in the TEC of patients with AD. Surprisingly, the analysis of the density, morphological features and spatial distribution of synapses in the neuropil showed no significant differences between AD and control samples. However, light microscopy studies showed that cortical thickness of the TEC was severely reduced in AD samples, but there were no changes in the volume occupied by neuronal and glial cell bodies, blood vessels, and neuropil. Thus, the present results indicate that there is a dramatic loss of absolute number of synapses, while the morphology of synaptic junctions and synaptic spatial distribution are maintained. How these changes affect cognitive impairment in AD remains to be elucidated.
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Masurkar AV. Towards a circuit-level understanding of hippocampal CA1 dysfunction in Alzheimer's disease across anatomical axes. JOURNAL OF ALZHEIMER'S DISEASE & PARKINSONISM 2018; 8:412. [PMID: 29928558 PMCID: PMC6005196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The hippocampus has been a primary region of study with regards to synaptic and functional changes in Alzheimer’s disease (AD) due to its involvement in early stages, specifically area CA1. However, most work in this area has treated CA1 as a homogeneous structure comprised of uniform neural circuits. Yet, there is a plethora of evidence that CA1 varies in its structure and function across anatomical axes. Here I review the heterogeneity of the functional and circuit architecture of hippocampal area CA1 across three primary anatomical axes. I also summarize evidence that AD differentially affects these subregions, as well as hypotheses as to why this may occur.
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Affiliation(s)
- Arjun V Masurkar
- Center for Cognitive Neurology, Department of Neurology, Department of Neuroscience & Physiology, NYU School of Medicine
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35
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Furcila D, DeFelipe J, Alonso-Nanclares L. A Study of Amyloid-β and Phosphotau in Plaques and Neurons in the Hippocampus of Alzheimer's Disease Patients. J Alzheimers Dis 2018; 64:417-435. [PMID: 29914033 PMCID: PMC6027945 DOI: 10.3233/jad-180173] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2018] [Indexed: 12/11/2022]
Abstract
The main pathological hallmarks in Alzheimer's disease (AD) are the presence of extracellular amyloid plaques, primarily consisting of amyloid-β (Aβ) peptide, and the accumulation of paired helical filaments of hyperphosphorylated tau protein (PHF-Tau) within neurons. Since CA1 is one of the most affected regions in AD, mainly at early stages, we have performed a detailed analysis of the CA1 region from 11 AD patients (demented and clinically similar; Braak stages IV-VI) to better understand the possible relationship between the presence and distribution of different neurochemical types of Aβ plaques and PHF-Tau immunoreactive (- ir) neurons. Hence, we have examined hippocampal sections in confocal microscopy images from double and triple-immunostained sections, to study labeled plaques and PHF-Tau-ir neurons using specific software tools. There are four main findings in the present study. First, the pyramidal layer of proximal CA1 (close to CA2) contains the smallest number of both plaques and PHF-Tau-ir neurons. Second, a large proportion of Aβ-ir plaques were also characterized by the presence of PHF-Tau-ir. Third, all plaques containing one of the two PHF-Tau isoforms also express the other isoform, that is, if a plaque contains PHFpS396, it also contains PHFAT8, and vice versa. Fourth, the coexpression study of both PHF-Tau isoforms in CA1 neurons revealed that most of the labeled neurons express only PHFpS396. Our findings further support the idea that AD is not a unique entity even within the same neuropathological stage, since the microanatomical/neurochemical changes that occur in the hippocampus greatly vary from one patient to another.
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Affiliation(s)
- Diana Furcila
- Laboratorio Cajal de Circuitos Corticales (CTB), Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales (CTB), Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal (CSIC), Madrid, Spain
| | - Lidia Alonso-Nanclares
- Laboratorio Cajal de Circuitos Corticales (CTB), Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal (CSIC), Madrid, Spain
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36
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Bolós M, Pallas-Bazarra N, Terreros-Roncal J, Perea JR, Jurado-Arjona J, Ávila J, Llorens-Martín M. Soluble Tau has devastating effects on the structural plasticity of hippocampal granule neurons. Transl Psychiatry 2017; 7:1267. [PMID: 29217824 PMCID: PMC5802513 DOI: 10.1038/s41398-017-0013-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/03/2017] [Accepted: 07/30/2017] [Indexed: 12/26/2022] Open
Abstract
Tau is a neuronal microtubule-associated protein with countless physiological functions. Although the detrimental effects of insoluble aggregated Tau have been widely studied, recent evidence supports the notion that soluble Tau (composed mostly of monomers and dimers) is also toxic for neurons. Here we evaluated the long-term impact of a single stereotaxic injection of human soluble Tau on hippocampal granule neurons in mice. At the ultrastructural level, soluble Tau reduced the number of afferent synapses and caused a dramatic depletion of synaptic vesicles both in afferent and efferent synapses. Furthermore, the use of an RFP-expressing retrovirus revealed that soluble Tau altered the morphology of newborn granule neurons and reduced their afferent (dendritic spines) and efferent (mossy fiber terminals) connectivity. Finally, soluble Tau caused specific impairment of behavioral pattern separation capacity. Our results thus demonstrate for the first time that soluble Tau causes long-term detrimental effects on the morphology and connectivity of newborn granule neurons and that these effects correlate with impaired behavioral pattern separation skills. These data might be relevant for the field of neurodegenerative disorders, since they contribute to reinforcing the pathological roles played by distinct Tau species in vivo.
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Affiliation(s)
- M Bolós
- grid.465524.4Department of Molecular Neuropathology, Centro de Biología Molecular “Severo Ochoa”, CBMSO, CSICUAM, Madrid, Spain ,0000 0004 1762 4012grid.418264.dNetwork Center for Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - N Pallas-Bazarra
- grid.465524.4Department of Molecular Neuropathology, Centro de Biología Molecular “Severo Ochoa”, CBMSO, CSICUAM, Madrid, Spain ,0000 0004 1762 4012grid.418264.dNetwork Center for Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - J Terreros-Roncal
- grid.465524.4Department of Molecular Neuropathology, Centro de Biología Molecular “Severo Ochoa”, CBMSO, CSICUAM, Madrid, Spain ,0000 0004 1762 4012grid.418264.dNetwork Center for Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - JR Perea
- grid.465524.4Department of Molecular Neuropathology, Centro de Biología Molecular “Severo Ochoa”, CBMSO, CSICUAM, Madrid, Spain ,0000 0004 1762 4012grid.418264.dNetwork Center for Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - J Jurado-Arjona
- grid.465524.4Department of Molecular Neuropathology, Centro de Biología Molecular “Severo Ochoa”, CBMSO, CSICUAM, Madrid, Spain ,0000 0004 1762 4012grid.418264.dNetwork Center for Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - J Ávila
- grid.465524.4Department of Molecular Neuropathology, Centro de Biología Molecular “Severo Ochoa”, CBMSO, CSICUAM, Madrid, Spain ,0000 0004 1762 4012grid.418264.dNetwork Center for Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - M Llorens-Martín
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa", CBMSO, CSICUAM, Madrid, Spain. .,Network Center for Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain. .,Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain.
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37
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Smith LA, McMahon LL. Deficits in synaptic function occur at medial perforant path-dentate granule cell synapses prior to Schaffer collateral-CA1 pyramidal cell synapses in the novel TgF344-Alzheimer's Disease Rat Model. Neurobiol Dis 2017; 110:166-179. [PMID: 29199135 DOI: 10.1016/j.nbd.2017.11.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 11/21/2017] [Accepted: 11/29/2017] [Indexed: 12/23/2022] Open
Abstract
Alzheimer's disease (AD) pathology begins decades prior to onset of clinical symptoms, and the entorhinal cortex and hippocampus are among the first and most extensively impacted brain regions. The TgF344-AD rat model, which more fully recapitulates human AD pathology in an age-dependent manner, is a next generation preclinical rodent model for understanding pathophysiological processes underlying the earliest stages of AD (Cohen et al., 2013). Whether synaptic alterations occur in hippocampus prior to reported learning and memory deficit is not known. Furthermore, it is not known if specific hippocampal synapses are differentially affected by progressing AD pathology, or if synaptic deficits begin to appear at the same age in males and females in this preclinical model. Here, we investigated the time-course of synaptic changes in basal transmission, paired-pulse ratio, as an indirect measure of presynaptic release probability, long-term potentiation (LTP), and dendritic spine density at two hippocampal synapses in male and ovariectomized female TgF344-AD rats and wildtype littermates, prior to reported behavioral deficits. Decreased basal synaptic transmission begins at medial perforant path-dentate granule cell (MPP-DGC) synapses prior to Schaffer-collateral-CA1 (CA3-CA1) synapses, in the absence of a change in paired-pulse ratio (PPR) or dendritic spine density. N-methyl-d-aspartate receptor (NMDAR)-dependent LTP magnitude is unaffected at CA3-CA1 synapses at 6, 9, and 12months of age, but is significantly increased at MPP-DGC synapses in TgF344-AD rats at 6months only. Sex differences were only observed at CA3-CA1 synapses where the decrease in basal transmission occurs at a younger age in males versus females. These are the first studies to define presymptomatic alterations in hippocampal synaptic transmission in the TgF344-AD rat model. The time course of altered synaptic transmission mimics the spread of pathology through hippocampus in human AD and provides support for this model as a valuable preclinical tool in elucidating pathological mechanisms of early synapse dysfunction in AD.
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Affiliation(s)
- Lindsey A Smith
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, USA
| | - Lori L McMahon
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, USA.
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38
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Billeh YN, Schaub MT. Feedforward architectures driven by inhibitory interactions. J Comput Neurosci 2017; 44:63-74. [PMID: 29139049 DOI: 10.1007/s10827-017-0669-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 10/10/2017] [Accepted: 10/17/2017] [Indexed: 11/25/2022]
Abstract
Directed information transmission is paramount for many social, physical, and biological systems. For neural systems, scientists have studied this problem under the paradigm of feedforward networks for decades. In most models of feedforward networks, activity is exclusively driven by excitatory neurons and the wiring patterns between them, while inhibitory neurons play only a stabilizing role for the network dynamics. Motivated by recent experimental discoveries of hippocampal circuitry, cortical circuitry, and the diversity of inhibitory neurons throughout the brain, here we illustrate that one can construct such networks even if the connectivity between the excitatory units in the system remains random. This is achieved by endowing inhibitory nodes with a more active role in the network. Our findings demonstrate that apparent feedforward activity can be caused by a much broader network-architectural basis than often assumed.
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Affiliation(s)
- Yazan N Billeh
- Computation and Neural Systems Program, California Institute of Technology, Pasadena, CA, USA.
- Allen Institute for Brain Science, Seattle, WA, USA.
| | - Michael T Schaub
- ICTEAM, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
- Institute for Data, Systems, and Society, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Engineering Science, University of Oxford, Oxford, UK.
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Inhibition of glycogen synthase kinase-3 by BTA-EG 4 reduces tau abnormalities in an organotypic brain slice culture model of Alzheimer's disease. Sci Rep 2017; 7:7434. [PMID: 28785087 PMCID: PMC5547074 DOI: 10.1038/s41598-017-07906-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/29/2017] [Indexed: 11/08/2022] Open
Abstract
Organotypic brain slice culture models provide an alternative to early stage in vivo studies as an integrated tissue system that can recapitulate key disease features, thereby providing an excellent platform for drug screening. We recently described a novel organotypic 3xTg-AD mouse brain slice culture model with key Alzheimer’s disease-like changes. We now highlight the potential of this model for testing disease-modifying agents and show that results obtained following in vivo treatment are replicated in brain slice cultures from 3xTg-AD mice. Moreover, we describe novel effects of the amyloid-binding tetra (ethylene glycol) derivative of benzothiazole aniline, BTA-EG4, on tau. BTA-EG4 significantly reduced tau phosphorylation in the absence of any changes in the amounts of amyloid precursor protein, amyloid-β or synaptic proteins. The reduction in tau phosphorylation was associated with inactivation of the Alzheimer’s disease-relevant major tau kinase, GSK-3. These findings highlight the utility of 3xTg-AD brain slice cultures as a rapid and reliable in vitro method for drug screening prior to in vivo testing. Furthermore, we demonstrate novel tau-directed effects of BTA-EG4 that are likely related to the ability of this agent to inactivate GSK-3. Our findings support the further exploration of BTA-EG4 as a candidate therapeutic for Alzheimer’s disease.
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40
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Sell GL, Schaffer TB, Margolis SS. Reducing expression of synapse-restricting protein Ephexin5 ameliorates Alzheimer's-like impairment in mice. J Clin Invest 2017; 127:1646-1650. [PMID: 28346227 PMCID: PMC5409082 DOI: 10.1172/jci85504] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 01/24/2017] [Indexed: 11/17/2022] Open
Abstract
Accumulation of amyloid-β (Aβ) protein may cause synapse degeneration and cognitive impairment in Alzheimer's disease (AD) by reactivating expression of the developmental synapse repressor protein Ephexin5 (also known as ARHGEF15). Here, we have reported that Aβ is sufficient to acutely promote the production of Ephexin5 in mature hippocampal neurons and in mice expressing human amyloid precursor protein (hAPP mice), a model for familial AD that produces high brain levels of Aβ. Ephexin5 expression was highly elevated in the hippocampi of human AD patients, indicating its potential relevance to AD. We also observed elevated Ephexin5 expression in the hippocampi of hAPP mice. Removal of Ephexin5 expression eliminated hippocampal dendritic spine loss and rescued AD-associated behavioral deficits in the hAPP mice. Furthermore, selective reduction of Ephexin5 expression using shRNA in the dentate gyrus of presymptomatic adolescent hAPP mice was sufficient to protect these mice from developing cognitive impairment. Thus, pathological elevation of Ephexin5 expression critically drives Aβ-induced memory impairment, and strategies aimed at reducing Ephexin5 levels may represent an effective approach to treating AD.
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Affiliation(s)
- Gabrielle L. Sell
- Department of Biological Chemistry and
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | | - Seth S. Margolis
- Department of Biological Chemistry and
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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41
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Protective Effect of 17β-Estradiol Upon Hippocampal Spine Density and Cognitive Function in an Animal Model of Vascular Dementia. Sci Rep 2017; 7:42660. [PMID: 28205591 PMCID: PMC5311994 DOI: 10.1038/srep42660] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 01/12/2017] [Indexed: 12/14/2022] Open
Abstract
The current study examined whether the steroid hormone, 17β-estradiol (E2) can exert long-lasting beneficial effects upon axonal health, synaptic plasticity, dementia-related amyloid-beta (Aβ) protein expression, and hippocampal-dependent cognitive function in an animal model of chronic cerebral hypoperfusion and vascular dementia (VaD). Chronic cerebral hypoperfusion and VaD was induced by bilateral common carotid artery occlusion (BCCAO) in adult male Sprague Dawley rats. Low dose E2 administered for the first 3-months after BCCAO exerted long-lasting beneficial effects, including significant neuroprotection of hippocampal CA1 neurons and preservation of hippocampal-dependent cognitive function when examined at 6-months after BCCAO. E2 treatment also prevented BCCAO-induced damage to hippocampal myelin sheaths and oligodendrocytes, enhanced expression of the synaptic proteins synaptophysin and PSD95 in the hippocampus, and prevented BCCAO-induced loss of total and mushroom dendritic spines in the hippocampal CA1 region. Furthermore, E2-treatment also reduced BCCAO induction of dementia-related proteins expression such as p-tau (PHF1), total ubiquitin, and Aβ1-42, when examined at 6 m after BCCAO. Taken as a whole, the results suggest that low-dose E2 replacement might be a potentially promising therapeutic modality to attenuate or block negative neurological consequences of chronic cerebral hypoperfusion and VaD.
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42
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Waworuntu RV, Hanania T, Boikess SR, Rex CS, Berg BM. Early life diet containing prebiotics and bioactive whey protein fractions increased dendritic spine density of rat hippocampal neurons. Int J Dev Neurosci 2016; 55:28-33. [DOI: 10.1016/j.ijdevneu.2016.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 09/02/2016] [Accepted: 09/03/2016] [Indexed: 01/15/2023] Open
Affiliation(s)
| | | | | | | | - Brian M. Berg
- Mead Johnson Pediatric Nutrition InstituteEvansvilleINUnited States
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Hansen HH, Fabricius K, Barkholt P, Niehoff ML, Morley JE, Jelsing J, Pyke C, Knudsen LB, Farr SA, Vrang N. The GLP-1 Receptor Agonist Liraglutide Improves Memory Function and Increases Hippocampal CA1 Neuronal Numbers in a Senescence-Accelerated Mouse Model of Alzheimer's Disease. J Alzheimers Dis 2016; 46:877-88. [PMID: 25869785 PMCID: PMC4878312 DOI: 10.3233/jad-143090] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Recent studies indicate that glucagon-like peptide 1 (GLP-1) receptor agonists, currently used in the management of type 2 diabetes, exhibit neurotrophic and neuroprotective effects in amyloid-β (Aβ) toxicity models of Alzheimer’s disease (AD). We investigated the potential pro-cognitive and neuroprotective effects of the once-daily GLP-1 receptor agonist liraglutide in senescence-accelerated mouse prone 8 (SAMP8) mice, a model of age-related sporadic AD not dominated by amyloid plaques. Six-month-old SAMP8 mice received liraglutide (100 or 500 μg/kg/day, s.c.) or vehicle once daily for 4 months. Vehicle-dosed age-matched 50% back-crossed as well as untreated young (4-month-old) SAMP8 mice were used as control groups for normal memory function. Vehicle-dosed 10-month-old SAMP8 mice showed significant learning and memory retention deficits in an active-avoidance T-maze, as compared to both control groups. Also, 10-month-old SAMP8 mice displayed no immunohistological signatures of amyloid-β plaques or hyperphosphorylated tau, indicating the onset of cognitive deficits prior to deposition of amyloid plaques and neurofibrillary tangles in this AD model. Liraglutide significantly increased memory retention and total hippocampal CA1 pyramidal neuron numbers in SAMP8 mice, as compared to age-matched vehicle-dosed SAMP8 mice. In conclusion, liraglutide delayed or partially halted the progressive decline in memory function associated with hippocampal neuronal loss in a mouse model of pathological aging with characteristics of neurobehavioral and neuropathological impairments observed in early-stage sporadic AD.
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Affiliation(s)
| | | | | | | | - John E Morley
- St. Louis University, Division of Geriatrics, St. Louis, MO, USA.,St. Louis University School of Medicine, Division of Endocrinology, St. Louis University, St. Louis, MO, USA
| | | | - Charles Pyke
- Diabetes Research, Novo Nordisk A/S, Maaloev, Denmark
| | | | - Susan A Farr
- St. Louis University, Division of Geriatrics, St. Louis, MO, USA.,Research and Development, Veterans Affairs Medical Center, St. Louis, MO, USA
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Tian JY, Chen WW, Cui J, Wang H, Chao C, Lu ZY, Bi YY. Effect of Lycium bararum polysaccharides on methylmercury-induced abnormal differentiation of hippocampal stem cells. Exp Ther Med 2016; 12:683-689. [PMID: 27446261 PMCID: PMC4950050 DOI: 10.3892/etm.2016.3415] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 02/04/2016] [Indexed: 12/19/2022] Open
Abstract
The aim of the present study was to observe the effects of a general extract of Lycium bararum polysaccharides (LBPs) on methylmercury (MeHg)-induced damage in hippocampus neural stem cells (hNSCs). The hippocampal tissues of embryonic day 16 Sprague-Dawley rats were extracted for the isolation, purification and cloning of hNSCs. Following passage and proliferation for 10 days, the cells were allocated at random into the following groups: Control, LBPs, MeHg and MeHg + LBPs. MTT and microtubule-associated protein 2 (MAP-2)/glial fibrillary acidic protein/Hoechst immunofluorescence tests were performed to detect the differentiation and growth of hNSCs in the various groups. The differentiation rate of MeHg-treated hNSCs and the perimeter of MAP-2-positive neurons were 3.632±0.63% and 62.36±5.58 µm, respectively, significantly lower compared with the control group values of 6.500±0.81% and 166±8.16 µm (P<0.05). Furthermore, the differentiation rate and the perimeter of MAP-2-positive neurons in LBPs groups cells was 7.75±0.59% and 253.3±11.21 µm, respectively, significantly higher compared with the control group (P<0.05). The same parameters in the MeHg + LBPs group were 5.92±0.98% and 111.9±6.07 µm, respectively, significantly higher than the MeHg group (P<0.05). The astrocyte differentiation rates in the MeHg and MeHg + LBPs group were 41.19±2.14 and 34.58±1.70, respectively (P<0.05). These results suggest that LBPs may promote the generation and development of new neurons and inhibit the MeHg-induced abnormal differentiation of astrocytes. Thus, LBPs may be considered to be a potential new treatment for MeHg-induced neurotoxicity in hNSCs.
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Affiliation(s)
- Jian-Ying Tian
- Department of Health, Labor Health and Environment, School of Public Health, Wuhan University, Wuhan, Hubei 430072, P.R. China; Department of Anatomy, Basic Medical School, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Wei-Wei Chen
- Department of Health, Labor Health and Environment, School of Public Health, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - Jing Cui
- Department of Health, Labor Health and Environment, School of Public Health, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - Hao Wang
- Department of Health, Labor Health and Environment, School of Public Health, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - Ci Chao
- Department of Health, Labor Health and Environment, School of Public Health, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - Zhi-Yan Lu
- Department of Health, Labor Health and Environment, School of Public Health, Wuhan University, Wuhan, Hubei 430072, P.R. China
| | - Yong-Yi Bi
- Department of Health, Labor Health and Environment, School of Public Health, Wuhan University, Wuhan, Hubei 430072, P.R. China
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Pandey MK, DeGrado TR. Glycogen Synthase Kinase-3 (GSK-3)-Targeted Therapy and Imaging. Am J Cancer Res 2016; 6:571-93. [PMID: 26941849 PMCID: PMC4775866 DOI: 10.7150/thno.14334] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 01/27/2016] [Indexed: 12/11/2022] Open
Abstract
Glycogen synthase kinase-3 (GSK-3) is associated with various key biological processes, including glucose regulation, apoptosis, protein synthesis, cell signaling, cellular transport, gene transcription, proliferation, and intracellular communication. Accordingly, GSK-3 has been implicated in a wide variety of diseases and specifically targeted for both therapeutic and imaging applications by a large number of academic laboratories and pharmaceutical companies. Here, we review the structure, function, expression levels, and ligand-binding properties of GSK-3 and its connection to various diseases. A selected list of highly potent GSK-3 inhibitors, with IC50 <20 nM for adenosine triphosphate (ATP)-competitive inhibitors and IC50 <5 μM for non-ATP-competitive inhibitors, were analyzed for structure activity relationships. Furthermore, ubiquitous expression of GSK-3 and its possible impact on therapy and imaging are also highlighted. Finally, a rational perspective and possible route to selective and effective GSK-3 inhibitors is discussed.
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Li T, Yu Y, Cai H. Effects of brain-derived neurotrophic factor-pretreated neuron stem cell transplantation on Alzheimer's disease model mice. Int J Clin Exp Med 2015; 8:21947-21955. [PMID: 26885166 PMCID: PMC4724012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/07/2015] [Indexed: 06/05/2023]
Abstract
Alzheimer's disease (AD) is a common case of dementia and its possible therapies, such as neuron stem cell (NSC) transplantation therapy, have been studied for years. In order to improve NSC transplantation effects, we were inspired to pretreat NSC using brain-derived neurotrophic factor (BDNF) before transplantation. The AD mouse model was constructed and effects of BDNF+NSC transplant group and traditional NSC transplant group were compared using the four indicators: conditions of learning and memory ability recovery tested by Morris Water Maze (MWM), number of basal forebrain cholinergic neurons, expression of synaptophysin, and number of acetylcholinesterase (ACHE)-positive fibers detected by chemical staining. Results showed all the four indicators were significantly lower in the AD model group than the control group (P < 0.05). Traditional NSC transplantation could improve these indicators to some extent but still possessed significant differences from the control group (P < 0.05). Especially, the BDNF+NSC transplant group showed significant improvements in the four indicators when compared with the AD model group (P < 0.05). Taken these data together, BDNF pretreatment improved the NSC transplantation effects, showing advantages over the traditional NSC transplantation. Our study could facilitate the application of stem cell transplantation therapy to AD treatment.
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Affiliation(s)
- Tong Li
- Department of Emergency, The First Affiliated Hospital, Zhejiang UniversityHangzhou 310003, Zhejiang, China
| | - Ying Yu
- Department of Intensive Care Unit, The First Affiliated Hospital, Zhejiang UniversityHangzhou 310003, Zhejiang, China
| | - Hongliu Cai
- Department of Intensive Care Unit, The First Affiliated Hospital, Zhejiang UniversityHangzhou 310003, Zhejiang, China
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Navarro D, Alvarado M, Navarrete F, Giner M, Obregon MJ, Manzanares J, Berbel P. Gestational and early postnatal hypothyroidism alters VGluT1 and VGAT bouton distribution in the neocortex and hippocampus, and behavior in rats. Front Neuroanat 2015; 9:9. [PMID: 25741243 PMCID: PMC4330898 DOI: 10.3389/fnana.2015.00009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 01/17/2015] [Indexed: 12/20/2022] Open
Abstract
Thyroid hormones are fundamental for the expression of genes involved in the development of the CNS and their deficiency is associated with a wide spectrum of neurological diseases including mental retardation, attention deficit-hyperactivity disorder and autism spectrum disorders. We examined in rat whether developmental and early postnatal hypothyroidism affects the distribution of vesicular glutamate transporter-1 (VGluT1; glutamatergic) and vesicular inhibitory amino acid transporter (VGAT; GABAergic) immunoreactive (ir) boutons in the hippocampus and somatosensory cortex, and the behavior of the pups. Hypothyroidism was induced by adding 0.02% methimazole (MMI) and 1% KClO4 to the drinking water starting at embryonic day 10 (E10; developmental hypothyroidism) and E21 (early postnatal hypothyroidism) until day of sacrifice at postnatal day 50. Behavior was studied using the acoustic prepulse inhibition (somatosensory attention) and the elevated plus-maze (anxiety-like assessment) tests. The distribution, density and size of VGluT1-ir and VGAT-ir boutons in the hippocampus and somatosensory cortex was abnormal in MMI pups and these changes correlate with behavioral changes, as prepulse inhibition of the startle response amplitude was reduced, and the percentage of time spent in open arms increased. In conclusion, both developmental and early postnatal hypothyroidism significantly decreases the ratio of GABAergic to glutamatergic boutons in dentate gyrus leading to an abnormal flow of information to the hippocampus and infragranular layers of the somatosensory cortex, and alter behavior in rats. Our data show cytoarchitectonic alterations in the basic excitatory hippocampal loop, and in local inhibitory circuits of the somatosensory cortex and hippocampus that might contribute to the delayed neurocognitive outcome observed in thyroid hormone deficient children born in iodine deficient areas, or suffering from congenital hypothyroidism.
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Affiliation(s)
- Daniela Navarro
- Departamento de Histología y Anatomía, Facultad de Medicina, Universidad Miguel HernándezAlicante, Spain
| | - Mayvi Alvarado
- Departamento de Histología y Anatomía, Facultad de Medicina, Universidad Miguel HernándezAlicante, Spain
- Instituto de Neuroetología, Universidad VeracruzanaXalapa, Veracruz, México
| | - Francisco Navarrete
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández and Consejo Superior de Investigaciones CientíficasAlicante, Spain
| | - Manuel Giner
- Departamento de Histología y Anatomía, Facultad de Medicina, Universidad Miguel HernándezAlicante, Spain
| | - Maria Jesus Obregon
- Instituto de investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de MadridMadrid, Spain
| | - Jorge Manzanares
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández and Consejo Superior de Investigaciones CientíficasAlicante, Spain
| | - Pere Berbel
- Departamento de Histología y Anatomía, Facultad de Medicina, Universidad Miguel HernándezAlicante, Spain
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Goggin SL, Caldwell KK, Cunningham LA, Allan AM. Prenatal alcohol exposure alters p35, CDK5 and GSK3β in the medial frontal cortex and hippocampus of adolescent mice. Toxicol Rep 2014; 1:544-553. [PMID: 25243109 PMCID: PMC4166584 DOI: 10.1016/j.toxrep.2014.08.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Fetal alcohol spectrum disorders (FASDs) are the number one cause of preventable mental retardation. An estimated 2-5% of children are diagnosed as having a FASD. While it is known that children prenatally exposed to alcohol experience cognitive deficits and a higher incidence of psychiatric illness later in life, the pathways underlying these abnormalities remain uncertain. GSK3β and CDK5 are protein kinases that are converging points for a vast number of signaling cascades, including those controlling cellular processes critical to learning and memory. We investigated whether levels of GSK3β and CDK5 are affected by moderate prenatal alcohol exposure (PAE), specifically in the hippocampus and medial frontal cortex of the adolescent mouse. In the present work we utilized immunoblotting techniques to demonstrate that moderate PAE increased hippocampal p35 and β-catenin, and decreased total levels of GSK3β, while increasing GSK3β Ser9 and Tyr216 phosphorylation. Interestingly, different alterations were seen in the medial frontal cortex where p35 and CDK5 were decreased and increased total GSK3β was accompanied by reduced Tyr216 of the enzyme. These results suggest that kinase dysregulation during adolescence might be an important contributing factor to the effects of PAE on hippocampal and medial frontal cortical functioning; and by extension, that global modulation of these kinases may produce differing effects depending on brain region.
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Affiliation(s)
- Samantha L Goggin
- Department of Neuroscience, University of New Mexico School of Medicine, Albuquerque, NM 87131, United States
| | - Kevin K Caldwell
- Department of Neuroscience, University of New Mexico School of Medicine, Albuquerque, NM 87131, United States
| | - Lee Anna Cunningham
- Department of Neuroscience, University of New Mexico School of Medicine, Albuquerque, NM 87131, United States
| | - Andrea M Allan
- Department of Neuroscience, University of New Mexico School of Medicine, Albuquerque, NM 87131, United States
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