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Almeida VN. Somatostatin and the pathophysiology of Alzheimer's disease. Ageing Res Rev 2024; 96:102270. [PMID: 38484981 DOI: 10.1016/j.arr.2024.102270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 03/09/2024] [Accepted: 03/09/2024] [Indexed: 03/28/2024]
Abstract
Among the central features of Alzheimer's disease (AD) progression are altered levels of the neuropeptide somatostatin (SST), and the colocalisation of SST-positive interneurons (SST-INs) with amyloid-β plaques, leading to cell death. In this theoretical review, I propose a molecular model for the pathogenesis of AD based on SST-IN hypofunction and hyperactivity. Namely, hypofunctional and hyperactive SST-INs struggle to control hyperactivity in medial regions in early stages, leading to axonal Aβ production through excessive presynaptic GABAB inhibition, GABAB1a/APP complex downregulation and internalisation. Concomitantly, excessive SST-14 release accumulates near SST-INs in the form of amyloids, which bind to Aβ to form toxic mixed oligomers. This leads to differential SST-IN death through excitotoxicity, further disinhibition, SST deficits, and increased Aβ release, fibrillation and plaque formation. Aβ plaques, hyperactive networks and SST-IN distributions thereby tightly overlap in the brain. Conversely, chronic stimulation of postsynaptic SST2/4 on gulutamatergic neurons by hyperactive SST-INs promotes intense Mitogen-Activated Protein Kinase (MAPK) p38 activity, leading to somatodendritic p-tau staining and apoptosis/neurodegeneration - in agreement with a near complete overlap between p38 and neurofibrillary tangles. This model is suitable to explain some of the principal risk factors and markers of AD progression, including mitochondrial dysfunction, APOE4 genotype, sex-dependent vulnerability, overactive glial cells, dystrophic neurites, synaptic/spine losses, inter alia. Finally, the model can also shed light on qualitative aspects of AD neuropsychology, especially within the domains of spatial and declarative (episodic, semantic) memory, under an overlying pattern of contextual indiscrimination, ensemble instability, interference and generalisation.
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Affiliation(s)
- Victor N Almeida
- Institute of Psychiatry, Faculty of Medicine, University of São Paulo (USP), Brazil; Faculty of Languages, Federal University of Minas Gerais (UFMG), Brazil.
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2
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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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3
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Kopel J, Sehar U, Choudhury M, Reddy PH. Alzheimer’s Disease and Alzheimer’s Disease-Related Dementias in African Americans: Focus on Caregivers. Healthcare (Basel) 2023; 11:healthcare11060868. [PMID: 36981525 PMCID: PMC10048201 DOI: 10.3390/healthcare11060868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/10/2023] [Accepted: 03/13/2023] [Indexed: 03/19/2023] Open
Abstract
Alzheimer’s disease (AD) and Alzheimer’s Disease-Related Dementias (ADRD) are chronic illnesses that are highly prevalent in African Americans (AA). AD and ADRD are caused by multiple factors, such as genetic mutations, modifiable and non-modifiable risk factors, and lifestyle. Histopathological, morphological, and cellular studies revealed how multiple cellular changes are implicated in AD and ADRD, including synaptic damage, inflammatory responses, hormonal imbalance, mitochondrial abnormalities, and neuronal loss, in addition to the accumulation of amyloid beta and phosphorylated tau in the brain. The contributions of race, ethnicity, location and socioeconomic status all have a significant impact on the care and support services available to dementia patients. Furthermore, disparities in health care are entangled with social, economic, and environmental variables that perpetuate disadvantages among different groups, particularly African Americans. As such, it remains important to understand how various racial and ethnic groups perceive, access, and experience health care. Considering that the mounting data shows AA may be more susceptible to AD than white people, the demographic transition creates significant hurdles in providing adequate care from family caregivers. Furthermore, there is growing recognition that AD and ADRD pose a significant stress on AA caregivers compared to white people. In this review, we examine the current literature on racial disparities in AD and ADRD, particularly concerning AA caregivers.
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Affiliation(s)
- Jonathan Kopel
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Ujala Sehar
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Moumita Choudhury
- Department of Speech, Language and Hearing Sciences, School Health Professions, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - P. Hemachandra Reddy
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Department of Speech, Language and Hearing Sciences, School Health Professions, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Department of Public Health, School of Population and Public Health, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Neurology, Departments of School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Nutritional Sciences Department, College of Human Sciences, Texas Tech University, Lubbock, TX 79409, USA
- Correspondence: ; Tel.: +1-806-743-3194
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Wallace CH, Oliveros G, Serrano PA, Rockwell P, Xie L, Figueiredo-Pereira M. Timapiprant, a prostaglandin D2 receptor antagonist, ameliorates pathology in a rat Alzheimer's model. Life Sci Alliance 2022; 5:e202201555. [PMID: 36167438 PMCID: PMC9515385 DOI: 10.26508/lsa.202201555] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/12/2022] [Accepted: 09/13/2022] [Indexed: 11/24/2022] Open
Abstract
We investigated the relevance of the prostaglandin D2 pathway in Alzheimer's disease, because prostaglandin D2 is a major prostaglandin in the brain. Thus, its contribution to Alzheimer's disease merits attention, given the known impact of the prostaglandin E2 pathway in Alzheimer's disease. We used the TgF344-AD transgenic rat model because it exhibits age-dependent and progressive Alzheimer's disease pathology. Prostaglandin D2 levels in hippocampi of TgF344-AD and wild-type littermates were significantly higher than prostaglandin E2. Prostaglandin D2 signals through DP1 and DP2 receptors. Microglial DP1 receptors were more abundant and neuronal DP2 receptors were fewer in TgF344-AD than in wild-type rats. Expression of the major brain prostaglandin D2 synthase (lipocalin-type PGDS) was the highest among 33 genes involved in the prostaglandin D2 and prostaglandin E2 pathways. We treated a subset of rats (wild-type and TgF344-AD males) with timapiprant, a potent highly selective DP2 antagonist in development for allergic inflammation treatment. Timapiprant significantly mitigated Alzheimer's disease pathology and cognitive deficits in TgF344-AD males. Thus, selective DP2 antagonists have potential as therapeutics to treat Alzheimer's disease.
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Affiliation(s)
- Charles H Wallace
- PhD Program in Biochemistry, The Graduate Center, CUNY, New York, NY, USA
| | - Giovanni Oliveros
- PhD Program in Biochemistry, The Graduate Center, CUNY, New York, NY, USA
| | | | - Patricia Rockwell
- PhD Program in Biochemistry, The Graduate Center, CUNY, New York, NY, USA
- Department of Biological Sciences, Hunter College, New York, NY, USA
| | - Lei Xie
- Department of Computer Science, Hunter College, New York, NY, USA
- Helen and Robert Appel Alzheimer's Disease Research Institute, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, Cornell University, New York, NY, USA
| | - Maria Figueiredo-Pereira
- PhD Program in Biochemistry, The Graduate Center, CUNY, New York, NY, USA
- Department of Biological Sciences, Hunter College, New York, NY, USA
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5
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Kim KR, Kim Y, Jeong HJ, Kang JS, Lee SH, Kim Y, Lee SH, Ho WK. Impaired pattern separation in Tg2576 mice is associated with hyperexcitable dentate gyrus caused by Kv4.1 downregulation. Mol Brain 2021; 14:62. [PMID: 33785038 PMCID: PMC8011083 DOI: 10.1186/s13041-021-00774-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/23/2021] [Indexed: 12/05/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder that causes memory loss. Most AD researches have focused on neurodegeneration mechanisms. Considering that neurodegenerative changes are not reversible, understanding early functional changes before neurodegeneration is critical to develop new strategies for early detection and treatment of AD. We found that Tg2576 mice exhibited impaired pattern separation at the early preclinical stage. Based on previous studies suggesting a critical role of dentate gyrus (DG) in pattern separation, we investigated functional changes in DG of Tg2576 mice. We found that granule cells in DG (DG-GCs) in Tg2576 mice showed increased action potential firing in response to long depolarizations and reduced 4-AP sensitive K+-currents compared to DG-GCs in wild-type (WT) mice. Among Kv4 family channels, Kv4.1 mRNA expression in DG was significantly lower in Tg2576 mice. We confirmed that Kv4.1 protein expression was reduced in Tg2576, and this reduction was restored by antioxidant treatment. Hyperexcitable DG and impaired pattern separation in Tg2576 mice were also recovered by antioxidant treatment. These results highlight the hyperexcitability of DG-GCs as a pathophysiologic mechanism underlying early cognitive deficits in AD and Kv4.1 as a new target for AD pathogenesis in relation to increased oxidative stress.
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Affiliation(s)
- Kyung-Ran Kim
- Department of Physiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Korea
| | - Yoonsub Kim
- Department of Physiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Korea
| | - Hyeon-Ju Jeong
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Jong-Sun Kang
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Sang Hun Lee
- Department of Physiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Korea
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Yujin Kim
- Department of Physiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Suk-Ho Lee
- Department of Physiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Korea
- Department of Brain and Cognitive Science, Seoul National University College of Natural Science, Seoul, Korea
| | - Won-Kyung Ho
- Department of Physiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Korea.
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Korea.
- Department of Brain and Cognitive Science, Seoul National University College of Natural Science, Seoul, Korea.
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6
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Webb CE, Foster CM, Horn MM, Kennedy KM, Rodrigue KM. Beta-amyloid burden predicts poorer mnemonic discrimination in cognitively normal older adults. Neuroimage 2020; 221:117199. [PMID: 32736001 PMCID: PMC7813158 DOI: 10.1016/j.neuroimage.2020.117199] [Citation(s) in RCA: 8] [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: 04/28/2020] [Revised: 06/29/2020] [Accepted: 07/22/2020] [Indexed: 11/18/2022] Open
Abstract
One of the earliest indicators of Alzheimer's disease pathology is the presence of beta-amyloid (Αβ) protein deposition. Significant amyloid deposition is evident even in older adults who exhibit little or no overt cognitive or memory impairment. Hippocampal-based processes that help distinguish between highly similar memory representations may be the most susceptible to early disease pathology. Amyloid associations with memory have been difficult to establish, possibly because typical memory assessments do not tax hippocampal operations sufficiently. Thus, the present study utilized a spatial mnemonic discrimination task designed to tax hippocampal pattern separation/completion processes in a sample of cognitively normal middle-aged and older adults (53-98 years old) who underwent PET 18F-Florbetapir Αβ scanning. The degree of interference between studied and new information varied, allowing for an examination of mnemonic discrimination as a function of mnemonic similarity. Results indicated that greater beta-amyloid burden was associated with poorer discrimination across decreasing levels of interference, suggesting that even subtle elevation of beta-amyloid in cognitively normal adults is associated with impoverished performance on a hippocampally demanding memory task. The present study demonstrates that degree of amyloid burden negatively impacts the ability of aging adults to accurately distinguish old from increasingly distinct new information, providing novel insight into the cognitive expression of beta-amyloid neuropathology.
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Affiliation(s)
- Christina E Webb
- Center for Vital Longevity, School of Behavioral and Brain Sciences, The University of Texas at Dallas, 1600 Viceroy Dr., Suite 800, Dallas, TX 75235, USA
| | - Chris M Foster
- Center for Vital Longevity, School of Behavioral and Brain Sciences, The University of Texas at Dallas, 1600 Viceroy Dr., Suite 800, Dallas, TX 75235, USA
| | - Marci M Horn
- Center for Vital Longevity, School of Behavioral and Brain Sciences, The University of Texas at Dallas, 1600 Viceroy Dr., Suite 800, Dallas, TX 75235, USA
| | - Kristen M Kennedy
- Center for Vital Longevity, School of Behavioral and Brain Sciences, The University of Texas at Dallas, 1600 Viceroy Dr., Suite 800, Dallas, TX 75235, USA
| | - Karen M Rodrigue
- Center for Vital Longevity, School of Behavioral and Brain Sciences, The University of Texas at Dallas, 1600 Viceroy Dr., Suite 800, Dallas, TX 75235, USA.
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Berg CN, Sinha N, Gluck MA. The Effects of APOE and ABCA7 on Cognitive Function and Alzheimer's Disease Risk in African Americans: A Focused Mini Review. Front Hum Neurosci 2019; 13:387. [PMID: 31749691 PMCID: PMC6848225 DOI: 10.3389/fnhum.2019.00387] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 10/16/2019] [Indexed: 01/12/2023] Open
Abstract
African Americans have double the prevalence of Alzheimer's disease (AD), as compared to European Americans. However, the underlying causes of this health disparity are due to a multitude of environmental, lifestyle, and genetic factors that are not yet fully understood. Here, we review the effects of the two largest genetic risk factors for AD in African Americans: Apolipoprotein E (APOE) and ABCA7. We will describe the direct effects of genetic variation on neural correlates of cognitive function and report the indirect modulating effects of genetic variation on modifiable AD risk factors, such as aerobic fitness. As a means of integrating previous findings, we present a novel schematic diagram to illustrate the many factors that contribute to AD risk and impaired cognitive function in older African Americans. Finally, we discuss areas that require further inquiry, and stress the importance of racially diverse and representative study populations.
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Affiliation(s)
- Chelsie N. Berg
- Center for Molecular and Behavioral Neuroscience, Rutgers University-Newark, Newark, NJ, United States
| | | | - Mark A. Gluck
- Center for Molecular and Behavioral Neuroscience, Rutgers University-Newark, Newark, NJ, United States
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8
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Dong Y, Kalueff AV, Song C. N -methyl- d -aspartate receptor-mediated calcium overload and endoplasmic reticulum stress are involved in interleukin-1beta-induced neuronal apoptosis in rat hippocampus. J Neuroimmunol 2017; 307:7-13. [DOI: 10.1016/j.jneuroim.2017.03.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 02/18/2017] [Accepted: 03/06/2017] [Indexed: 12/13/2022]
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9
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Augustinack JC, van der Kouwe AJW. Postmortem imaging and neuropathologic correlations. HANDBOOK OF CLINICAL NEUROLOGY 2016; 136:1321-39. [PMID: 27430472 DOI: 10.1016/b978-0-444-53486-6.00069-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Postmortem imaging refers to scanning autopsy specimens using magnetic resonance imaging (MRI) or optical imaging. This chapter summarizes postmortem imaging and its usefulness in brain mapping. Standard in vivo MRI has limited resolution due to time constraints and does not deliver cortical boundaries (e.g., Brodmann areas). Postmortem imaging offers a means to obtain ultra-high-resolution images with appropriate contrast for delineating cortical regions. Postmortem imaging provides the ability to validate MRI properties against histologic stained sections. This approach has enabled probabilistic mapping that is based on ex vivo MRI contrast, validated to histology, and subsequently mapped on to an in vivo model. This chapter emphasizes structural imaging, which can be validated with histologic assessment. Postmortem imaging has been applied to neuropathologic studies as well. This chapter includes many ex vivo studies, but focuses on studies of the medial temporal lobe, often involved in neurologic disease. New research using optical imaging is also highlighted.
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Affiliation(s)
- Jean C Augustinack
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA.
| | - André J W van der Kouwe
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
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10
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Kasten CR, Boehm SL. Identifying the role of pre-and postsynaptic GABA(B) receptors in behavior. Neurosci Biobehav Rev 2015; 57:70-87. [PMID: 26283074 DOI: 10.1016/j.neubiorev.2015.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 06/18/2015] [Accepted: 08/09/2015] [Indexed: 12/15/2022]
Abstract
Although many reviews exist characterizing the molecular differences of GABAB receptor isoforms, there is no current review of the in vivo effects of these isoforms. The current review focuses on whether the GABAB1a and GABAB1b isoforms contribute differentially to behaviors in isoform knockout mice. The roles of these receptors have primarily been characterized in cognitive, anxiety, and depressive phenotypes. Currently, the field supports a role of GABAB1a in memory maintenance and protection against an anhedonic phenotype, whereas GABAB1b appears to be involved in memory formation and a susceptibility to developing an anhedonic phenotype. Although GABAB receptors have been strongly implicated in drug abuse phenotypes, no isoform-specific work has been done in this field. Future directions include developing site-specific isoform knockdown to identify the role of different brain regions in behavior, as well as identifying how these isoforms are involved in development of behavioral phenotypes.
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Affiliation(s)
- Chelsea R Kasten
- Department of Psychology, Indianapolis University Purdue University-Indianapolis, 402N Blackford St LD 124, Indianapolis, IN 46202, United States.
| | - Stephen L Boehm
- Department of Psychology, Indianapolis University Purdue University-Indianapolis, 402N Blackford St LD 124, Indianapolis, IN 46202, United States; Indiana Alcohol Research Center, 545 Barnhill Drive EH 317, Indianapolis, IN, United States.
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11
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Salgado-Puga K, Prado-Alcalá RA, Peña-Ortega F. Amyloid β Enhances Typical Rodent Behavior While It Impairs Contextual Memory Consolidation. Behav Neurol 2015; 2015:526912. [PMID: 26229236 PMCID: PMC4502279 DOI: 10.1155/2015/526912] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 06/04/2015] [Indexed: 01/22/2023] Open
Abstract
Alzheimer's disease (AD) is associated with an early hippocampal dysfunction, which is likely induced by an increase in soluble amyloid beta peptide (Aβ). This hippocampal failure contributes to the initial memory deficits observed both in patients and in AD animal models and possibly to the deterioration in activities of daily living (ADL). One typical rodent behavior that has been proposed as a hippocampus-dependent assessment model of ADL in mice and rats is burrowing. Despite the fact that AD transgenic mice show some evidence of reduced burrowing, it has not been yet determined whether or not Aβ can affect this typical rodent behavior and whether this alteration correlates with the well-known Aβ-induced memory impairment. Thus, the purpose of this study was to test whether or not Aβ affects burrowing while inducing hippocampus-dependent memory impairment. Surprisingly, our results show that intrahippocampal application of Aβ increases burrowing while inducing memory impairment. We consider that this Aβ-induced increase in burrowing might be associated with a mild anxiety state, which was revealed by increased freezing behavior in the open field, and conclude that Aβ-induced hippocampal dysfunction is reflected in the impairment of ADL and memory, through mechanisms yet to be determined.
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Affiliation(s)
- Karla Salgado-Puga
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, 76230 Juriquilla, Querétaro, QRO, Mexico
| | - Roberto A. Prado-Alcalá
- Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, Universidad Nacional Autónoma de México, 76230 Juriquilla, Querétaro, QRO, Mexico
| | - Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, 76230 Juriquilla, Querétaro, QRO, Mexico
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12
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Nenov MN, Tempia F, Denner L, Dineley KT, Laezza F. Impaired firing properties of dentate granule neurons in an Alzheimer's disease animal model are rescued by PPARγ agonism. J Neurophysiol 2014; 113:1712-26. [PMID: 25540218 PMCID: PMC4359997 DOI: 10.1152/jn.00419.2014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Early cognitive impairment in Alzheimer's disease (AD) correlates with medial temporal lobe dysfunction, including two areas essential for memory formation: the entorhinal cortex and dentate gyrus (DG). In the Tg2576 animal model for AD amyloidosis, activation of the peroxisome proliferator-activated receptor-gamma (PPARγ) with rosiglitazone (RSG) ameliorates hippocampus-dependent cognitive impairment and restores aberrant synaptic activity at the entorhinal cortex to DG granule neuron inputs. It is unknown, however, whether intrinsic firing properties of DG granule neurons in these animals are affected by amyloid-β pathology and if they are sensitive to RSG treatment. Here, we report that granule neurons from 9-mo-old wild-type and Tg2576 animals can be segregated into two cell types with distinct firing properties and input resistance that correlate with less mature type I and more mature type II neurons. The DG type I cell population was greater than type II in wild-type littermates. In the Tg2576 animals, the type I and type II cell populations were nearly equal but could be restored to wild-type levels through cognitive enhancement with RSG. Furthermore, Tg2576 cell firing frequency and spike after depolarization were decreased in type I and increased in type II cells, both of which could also be restored to wild-type levels upon RSG treatment. That these parameters were restored by PPARγ activation emphasizes the therapeutic value of RSG against early AD cognitive impairment.
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Affiliation(s)
- Miroslav N Nenov
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, Texas
| | - Filippo Tempia
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, Texas
| | - Larry Denner
- Department of Internal Medicine, The University of Texas Medical Branch, Galveston, Texas; Center for Addiction Research, The University of Texas Medical Branch, Galveston, Texas; Mitchell Center for Neurodegenerative Diseases, The University of Texas Medical Branch, Galveston, Texas; and
| | - Kelly T Dineley
- Department of Neurology, The University of Texas Medical Branch, Galveston, Texas; Center for Addiction Research, The University of Texas Medical Branch, Galveston, Texas; Mitchell Center for Neurodegenerative Diseases, The University of Texas Medical Branch, Galveston, Texas; and
| | - Fernanda Laezza
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, Texas; Center for Addiction Research, The University of Texas Medical Branch, Galveston, Texas; Mitchell Center for Neurodegenerative Diseases, The University of Texas Medical Branch, Galveston, Texas; and Center for Biomedical Engineering, The University of Texas Medical Branch, Galveston, Texas
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13
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Abstract
Supplemental digital content is available in the text. Understanding the pathophysiologic mechanisms underlying Alzheimer disease relies on knowledge of disease onset and the sequence of development of brain pathologies. We present a comprehensive analysis of early and progressive changes in a mouse model that demonstrates a full spectrum of characteristic Alzheimer disease–like pathologies. This model demonstrates an altered immune redox state reminiscent of the human disease and capitalizes on data indicating critical differences between human and mouse immune responses, particularly in nitric oxide levels produced by immune activation of the NOS2 gene. Using the APPSwDI+/+/mNos2−/− (CVN-AD) mouse strain, we show a sequence of pathologic events leading to neurodegeneration,which include pathologically hyperphosphorylated tau in the perforant pathway at 6 weeks of age progressing to insoluble tau, early appearance of β-amyloid peptides in perivascular deposits around blood vessels in brain regions known to be vulnerable to Alzheimer disease, and progression to damage and overt loss in select vulnerable neuronal populations in these regions. The role of species differences between hNOS2 and mNos2 was supported by generating mice in which the human NOS2 gene replaced mNos2. When crossed with CVN-AD mice, pathologic characteristics of this new strain (APPSwDI+/−/HuNOS2tg+/+/mNos2−/−) mimicked the pathologic phenotypes found in the CVN-AD strain.
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14
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Koh MT, Spiegel AM, Gallagher M. Age-associated changes in hippocampal-dependent cognition in Diversity Outbred mice. Hippocampus 2014; 24:1300-7. [PMID: 24909986 DOI: 10.1002/hipo.22311] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2014] [Indexed: 11/05/2022]
Abstract
Episodic memory impairment due to aging has been linked to hippocampal dysfunction. Evidence exists for alterations in specific circuits within the hippocampal system that are closely coupled to individual differences in the presence and severity of such memory loss. Here, we used the newly developed Diversity Outbred (DO) mouse that was designed to model the genetic diversity in human populations. Young and aged DO mice were tested in a hippocampal-dependent water maze task. Young mice showed higher proficiency and more robust memory compared to the overall performance of aged mice. A substantial number of the older mice, however, performed on par with the normative performance of the younger mice. Stereological quantification of somatostatin-immunoreactive neurons in the dentate hilus showed that high-performing young and unimpaired aged mice had similar numbers of somatostatin-positive interneurons, while aged mice that were impaired in the spatial task had significantly fewer such neurons. These data in the DO model tie loss of hilar inhibitory network integrity to age-related memory impairment, paralleling data in other rodent models.
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Affiliation(s)
- Ming Teng Koh
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, Maryland
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15
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Spiegel AM, Koh MT, Vogt NM, Rapp PR, Gallagher M. Hilar interneuron vulnerability distinguishes aged rats with memory impairment. J Comp Neurol 2014; 521:3508-23. [PMID: 23749483 DOI: 10.1002/cne.23367] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 04/30/2013] [Accepted: 05/23/2013] [Indexed: 01/24/2023]
Abstract
Hippocampal interneuron populations are reportedly vulnerable to normal aging. The relationship between interneuron network integrity and age-related memory impairment, however, has not been tested directly. That question was addressed in the present study using a well-characterized model in which outbred, aged, male Long-Evans rats exhibit a spectrum of individual differences in hippocampal-dependent memory. Selected interneuron populations in the hippocampus were visualized for stereological quantification with a panel of immunocytochemical markers, including glutamic acid decarboxylase-67 (GAD67), somatostatin, and neuropeptide Y. The overall pattern of results was that, although the numbers of GAD67- and somatostatin-positive interneurons declined with age across multiple fields of the hippocampus, alterations specifically related to the cognitive outcome of aging were observed exclusively in the hilus of the dentate gyrus. Because the total number of NeuN-immunoreactive hilar neurons was unaffected, the decline observed with other markers likely reflects a loss of target protein rather than neuron death. In support of that interpretation, treatment with the atypical antiepileptic levetiracetam at a low dose shown previously to improve behavioral performance fully restored hilar SOM expression in aged, memory-impaired rats. Age-related decreases in GAD67- and somatostatin-immunoreactive neuron number beyond the hilus were regionally selective and spared the CA1 field of the hippocampus entirely. Together these findings confirm the vulnerability of hippocampal interneurons to normal aging and highlight that the integrity of a specific subpopulation in the hilus is coupled with age-related memory impairment.
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Affiliation(s)
- Amy M Spiegel
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, Maryland, 21218
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16
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Liu H, Yang L, Zhao Y, Zeng G, Wu Y, Chen Y, Zhang J, Zeng Q. Estrogen is a novel regulator of Tnfaip1 in mouse hippocampus. Int J Mol Med 2014; 34:219-27. [PMID: 24737445 DOI: 10.3892/ijmm.2014.1742] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 02/26/2014] [Indexed: 11/06/2022] Open
Abstract
Tumor necrosis factor‑induced protein 1 (Tnfaip1), also known as B12, has been previously identified as a tumor necrosis factor-α (TNF-α)-inducible protein and is involved in the cytokinesis signaling pathway, DNA synthesis, innate immunity, cell apoptosis, Alzheimer's disease (AD) and type 2 diabetic nephropathy. However, little is known regarding the expression of Tnfaip1 in various tissues or its accurate role in these physiological functions. The focus of this study was on Tnfaip1 expression in different tissues, with a high expression in mouse hippocampus being identified. The age- and gender‑related expression of Tnfaip1 in hippocampus was also investigated. The distribution of Tnfaip1 was mapped using fluorescent immunostaining. Although immunoactivity was found in the CA1, CA3 and DG subregions of the hippocampus in E17.5 and P6 mice, strong staining was only detected in the CA3 subregion in adult mice. These data suggested that Tnfaip1 expression in hippocampus may be regulated by estrogen. Further study showed that the expression of Tnfaip1 in the hippocampus was significantly increased in ovariecto-mized mice compared to Sham mice. In cultured primary hippocampal cells, Tnfaip1 showed different expression levels in different treatments of estrogen or estrogen receptor antagonists. Additional experiments demonstrated the existence of a binding site of ERβ in the Tnfaip1 promoter region, and that ERβ was able to upregulate Tnfaip1 expression. Our study identified a new regulatory factor and a primary regulatory mechanism of Tnfaip1 expression in hippocampus. Since both hippocampus and estrogen are crucial in AD, the results also showed a potential association between Tnfaip1 and hippocampal-related diseases, such as AD, which may be affected by the estrogen level.
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Affiliation(s)
- Hui Liu
- Department of Life Science, Hunan Agricultural University, Changsha, Hunan 410128, P.R. China
| | - Liping Yang
- Department of Enviromental Science, Changsha Environmental Protection College, Changsha, Hunan 410004, P.R. China
| | - Yingchun Zhao
- Department of Biostatistics and Bioinformatics, Tulane University, New Orleans, LA 70112, USA
| | - Guihua Zeng
- Department of Enviromental Science, Changsha Environmental Protection College, Changsha, Hunan 410004, P.R. China
| | - Yaosong Wu
- Laboratory of Molecular Biology, Henan University of Traditional Chinese Medicine, Zhengzhou, Henan 410208, P.R. China
| | - Yulong Chen
- Laboratory of Molecular Biology, Henan University of Traditional Chinese Medicine, Zhengzhou, Henan 410208, P.R. China
| | - Jian Zhang
- Key Laboratory of Protein Chemistry and Developmental Biology, Ministry of Education of China, Department of Biochemistry and Molecular Biology, College of Life Science, Hunan Normal University, Changsha, Hunan 410081, P.R. China
| | - Qingru Zeng
- Department of Life Science, Hunan Agricultural University, Changsha, Hunan 410128, P.R. China
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17
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Maruszak A, Thuret S. Why looking at the whole hippocampus is not enough-a critical role for anteroposterior axis, subfield and activation analyses to enhance predictive value of hippocampal changes for Alzheimer's disease diagnosis. Front Cell Neurosci 2014; 8:95. [PMID: 24744700 PMCID: PMC3978283 DOI: 10.3389/fncel.2014.00095] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Accepted: 03/13/2014] [Indexed: 01/06/2023] Open
Abstract
The hippocampus is one of the earliest affected brain regions in Alzheimer's disease (AD) and its dysfunction is believed to underlie the core feature of the disease-memory impairment. Given that hippocampal volume is one of the best AD biomarkers, our review focuses on distinct subfields within the hippocampus, pinpointing regions that might enhance the predictive value of current diagnostic methods. Our review presents how changes in hippocampal volume, shape, symmetry and activation are reflected by cognitive impairment and how they are linked with neurogenesis alterations. Moreover, we revisit the functional differentiation along the anteroposterior longitudinal axis of the hippocampus and discuss its relevance for AD diagnosis. Finally, we indicate that apart from hippocampal subfield volumetry, the characteristic pattern of hippocampal hyperactivation associated with seizures and neurogenesis changes is another promising candidate for an early AD biomarker that could become also a target for early interventions.
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Affiliation(s)
- Aleksandra Maruszak
- Centre for the Cellular Basis of Behaviour, Department of Neuroscience, Institute of Psychiatry, King’s College LondonLondon, UK
| | - Sandrine Thuret
- Centre for the Cellular Basis of Behaviour, Department of Neuroscience, Institute of Psychiatry, King’s College LondonLondon, UK
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18
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Wilke SA, Raam T, Antonios JK, Bushong EA, Koo EH, Ellisman MH, Ghosh A. Specific disruption of hippocampal mossy fiber synapses in a mouse model of familial Alzheimer's disease. PLoS One 2014; 9:e84349. [PMID: 24454724 PMCID: PMC3890281 DOI: 10.1371/journal.pone.0084349] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Accepted: 11/14/2013] [Indexed: 02/02/2023] Open
Abstract
The earliest stages of Alzheimer's disease (AD) are characterized by deficits in memory and cognition indicating hippocampal pathology. While it is now recognized that synapse dysfunction precedes the hallmark pathological findings of AD, it is unclear if specific hippocampal synapses are particularly vulnerable. Since the mossy fiber (MF) synapse between dentate gyrus (DG) and CA3 regions underlies critical functions disrupted in AD, we utilized serial block-face electron microscopy (SBEM) to analyze MF microcircuitry in a mouse model of familial Alzheimer's disease (FAD). FAD mutant MF terminal complexes were severely disrupted compared to control - they were smaller, contacted fewer postsynaptic spines and had greater numbers of presynaptic filopodial processes. Multi-headed CA3 dendritic spines in the FAD mutant condition were reduced in complexity and had significantly smaller sites of synaptic contact. Significantly, there was no change in the volume of classical dendritic spines at neighboring inputs to CA3 neurons suggesting input-specific defects in the early course of AD related pathology. These data indicate a specific vulnerability of the DG-CA3 network in AD pathogenesis and demonstrate the utility of SBEM to assess circuit specific alterations in mouse models of human disease.
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Affiliation(s)
- Scott A. Wilke
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Tara Raam
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Joseph K. Antonios
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Eric A. Bushong
- National Center for Microscopy and Imaging Research, University of California San Diego, La Jolla, California, United States of America
| | - Edward H. Koo
- Department of Neurosciences, University of California San Diego, La Jolla, California, United States of America
| | - Mark H. Ellisman
- National Center for Microscopy and Imaging Research, University of California San Diego, La Jolla, California, United States of America
| | - Anirvan Ghosh
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
- Neuroscience Discovery and Translational Area, pRED, F. Hoffmann-La Roche, Basel, Switzerland
- * E-mail:
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19
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Honey RC, Iordanova MD, Good M. Associative structures in animal learning: dissociating elemental and configural processes. Neurobiol Learn Mem 2013; 108:96-103. [PMID: 23769767 DOI: 10.1016/j.nlm.2013.06.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 05/31/2013] [Accepted: 06/04/2013] [Indexed: 11/18/2022]
Abstract
The central concern of associative learning theory is to provide an account of behavioral adaptation that is parsimonious in addressing three key questions: (1) under what conditions does learning occur, (2) what are the associative structures involved, and (3) how do these affect behavior? The principle focus here is on the second question, concerning associative structures, but we will have cause to touch on the others in passing. This question is one that has exercised theorists since Pavlov's descriptions of the conditioning process, where he identifies the shared significance of the study of conditioned reflexes for psychologists and neuroscientists alike.
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20
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Jain S, Yoon SY, Zhu L, Brodbeck J, Dai J, Walker D, Huang Y. Arf4 determines dentate gyrus-mediated pattern separation by regulating dendritic spine development. PLoS One 2012; 7:e46340. [PMID: 23050017 PMCID: PMC3457985 DOI: 10.1371/journal.pone.0046340] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Accepted: 08/29/2012] [Indexed: 11/18/2022] Open
Abstract
The ability to distinguish between similar experiences is a critical feature of episodic memory and is primarily regulated by the dentate gyrus (DG) region of the hippocampus. However, the molecular mechanisms underlying such pattern separation tasks are poorly understood. We report a novel role for the small GTPase ADP ribosylation factor 4 (Arf4) in controlling pattern separation by regulating dendritic spine development. Arf4(+/-) mice at 4-5 months of age display severe impairments in a pattern separation task, as well as significant dendritic spine loss and smaller miniature excitatory post-synaptic currents (mEPSCs) in granule cells of the DG. Arf4 knockdown also decreases spine density in primary neurons, whereas Arf4 overexpression promotes spine development. A constitutively active form of Arf4, Arf4-Q71L, promotes spine density to an even greater extent than wildtype Arf4, whereas the inactive Arf4-T31N mutant does not increase spine density relative to controls. Arf4's effects on spine development are regulated by ASAP1, a GTPase-activating protein that modulates Arf4 GTPase activity. ASAP1 overexpression decreases spine density, and this effect is partially rescued by concomitant overexpression of wildtype Arf4 or Arf4-Q71L. In addition, Arf4 overexpression rescues spine loss in primary neurons from an Alzheimer's disease-related apolipoprotein (apo) E4 mouse model. Our findings suggest that Arf4 is a critical modulator of DG-mediated pattern separation by regulating dendritic spine development.
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Affiliation(s)
- Sachi Jain
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, California, United States of America
| | - Seo Yeon Yoon
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
| | - Lei Zhu
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
| | - Jens Brodbeck
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
| | - Jessica Dai
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
| | - David Walker
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Gladstone Institute of Cardiovascular Disease, San Francisco, California, United States of America
| | - Yadong Huang
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Gladstone Institute of Cardiovascular Disease, San Francisco, California, United States of America
- Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, California, United States of America
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
- Department of Pathology, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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21
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Takuma K, Mizoguchi H, Funatsu Y, Kitahara Y, Ibi D, Kamei H, Matsuda T, Koike K, Inoue M, Nagai T, Yamada K. Placental extract improves hippocampal neuronal loss and fear memory impairment resulting from chronic restraint stress in ovariectomized mice. J Pharmacol Sci 2012; 120:89-97. [PMID: 22971911 PMCID: PMC7128920 DOI: 10.1254/jphs.12115fp] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
We have recently found that combination of ovariectomy (OVX) and chronic restraint stress causes cognitive dysfunction and reduces hippocampal CA3 neurons in female rats and mice and that estrogen replacement and chronic treatment with Ginkgo biloba extract EGb 761 suppress the OVX/stress-induced behavioral and morphological changes. In this study, we examined the effect of placental extract on the memory impairment and neuromorphological change in OVX/stress-subjected mice. Female Slc:ICR strain mice were randomly divided into four groups: vehicle-treated OVX, porcine placental extract (120 and 2160 mg/kg)-treated OVX, and sham-operated control groups. Two weeks after surgical operation, OVX mice underwent restraint stress for 21 days (6 h/day), and all animals were then subjected to a contextual fear conditioning test followed by morphological examination by Nissl staining. Placental extract was orally administered once daily until the behavioral analysis was carried out. Chronic treatment with both doses of placental extract improved the OVX/stress-induced fear memory impairment and Nissl-positive cell loss of the hippocampal CA3 region, although it did not affect the loss of bone mineral density and increase in body weight after OVX. These results have important implications for the neuroprotective and cognition-enhancing effects of placental extract in postmenopausal women.
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Affiliation(s)
- Kazuhiro Takuma
- Laboratory of Neuropsychopharmacology, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan
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22
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Abstract
Alzheimer's disease (AD) and epilepsy are separated in the medical community, but seizures occur in some patients with AD, and AD is a risk factor for epilepsy. Furthermore, memory impairment is common in patients with epilepsy. The relationship between AD and epilepsy remains an important question because ideas for therapeutic approaches could be shared between AD and epilepsy research laboratories if AD and epilepsy were related. Here we focus on one of the many types of epilepsy, temporal lobe epilepsy (TLE), because patients with TLE often exhibit memory impairment, depression and other comorbidities that occur in AD. Moreover, the seizures that occur in patients with AD may be nonconvulsive, which occur in patients with TLE. Here we first compare neuropathology in TLE and AD with an emphasis on the hippocampus, which is central to both AD and TLE research. Then we compare animal models of AD pathology with animal models of TLE. Although many aspects of the comparisons are still controversial, there is one conclusion that we suggest is clear: some animal models of TLE could be used to help address questions in AD research, and some animal models of AD pathology are bona fide animal models of epilepsy.
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Affiliation(s)
- Helen E Scharfman
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA and Departments of Child & Adolescent Psychiatry, Physiology & Neuroscience, and Psychiatry, New York University Langone Medical Center, 550 First Avenue, New York, NY 10016, USA Tel.: +1 845 398 5427 Fax: +1 845 398 5422
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