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Terreros-Roncal J, Flor-García M, Moreno-Jiménez EP, Rodríguez-Moreno CB, Márquez-Valadez B, Gallardo-Caballero M, Rábano A, Llorens-Martín M. Methods to study adult hippocampal neurogenesis in humans and across the phylogeny. Hippocampus 2023; 33:271-306. [PMID: 36259116 PMCID: PMC7614361 DOI: 10.1002/hipo.23474] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/16/2022] [Accepted: 09/25/2022] [Indexed: 11/09/2022]
Abstract
The hippocampus hosts the continuous addition of new neurons throughout life-a phenomenon named adult hippocampal neurogenesis (AHN). Here we revisit the occurrence of AHN in more than 110 mammalian species, including humans, and discuss the further validation of these data by single-cell RNAseq and other alternative techniques. In this regard, our recent studies have addressed the long-standing controversy in the field, namely whether cells positive for AHN markers are present in the adult human dentate gyrus (DG). Here we review how we developed a tightly controlled methodology, based on the use of high-quality brain samples (characterized by short postmortem delays and ≤24 h of fixation in freshly prepared 4% paraformaldehyde), to address human AHN. We review that the detection of AHN markers in samples fixed for 24 h required mild antigen retrieval and chemical elimination of autofluorescence. However, these steps were not necessary for samples subjected to shorter fixation periods. Moreover, the detection of labile epitopes (such as Nestin) in the human hippocampus required the use of mild detergents. The application of this strictly controlled methodology allowed reconstruction of the entire AHN process, thus revealing the presence of neural stem cells, proliferative progenitors, neuroblasts, and immature neurons at distinct stages of differentiation in the human DG. The data reviewed here demonstrate that methodology is of utmost importance when studying AHN by means of distinct techniques across the phylogenetic scale. In this regard, we summarize the major findings made by our group that emphasize that overlooking fundamental technical principles might have consequences for any given research field.
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Affiliation(s)
- Julia Terreros-Roncal
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Miguel Flor-García
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Elena P Moreno-Jiménez
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Carla B Rodríguez-Moreno
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Berenice Márquez-Valadez
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Marta Gallardo-Caballero
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Alberto Rábano
- Neuropathology Department, CIEN Foundation, Madrid, Spain
| | - María Llorens-Martín
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
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Kim TA, Syty MD, Wu K, Ge S. Adult hippocampal neurogenesis and its impairment in Alzheimer's disease. Zool Res 2022; 43:481-496. [PMID: 35503338 PMCID: PMC9113964 DOI: 10.24272/j.issn.2095-8137.2021.479] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/25/2022] [Indexed: 11/07/2022] Open
Abstract
Adult neurogenesis is the creation of new neurons which integrate into the existing neural circuit of the adult brain. Recent evidence suggests that adult hippocampal neurogenesis (AHN) persists throughout life in mammals, including humans. These newborn neurons have been implicated to have a crucial role in brain functions such as learning and memory. Importantly, studies have also found that hippocampal neurogenesis is impaired in neurodegenerative and neuropsychiatric diseases. Alzheimer's disease (AD) is one of the most common forms of dementia affecting millions of people. Cognitive dysfunction is a common symptom of AD patients and progressive memory loss has been attributed to the degeneration of the hippocampus. Therefore, there has been growing interest in identifying how hippocampal neurogenesis is affected in AD. However, the link between cognitive decline and changes in hippocampal neurogenesis in AD is poorly understood. In this review, we summarized the recent literature on AHN and its impairments in AD.
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Affiliation(s)
- Thomas A Kim
- Department of Neurobiology & Behavior, SUNY at Stony Brook, Stony Brook, NY 11794, USA
- Medical Scientist Training Program (MSTP), Renaissance School of Medicine at SUNY, Stony Brook, Stony Brook, NY 11794, USA
| | - Michelle D Syty
- Department of Neurobiology & Behavior, SUNY at Stony Brook, Stony Brook, NY 11794, USA
| | - Kaitlyn Wu
- Department of Neurobiology & Behavior, SUNY at Stony Brook, Stony Brook, NY 11794, USA
| | - Shaoyu Ge
- Department of Neurobiology & Behavior, SUNY at Stony Brook, Stony Brook, NY 11794, USA. E-mail:
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Jung HY, Kim W, Hahn KR, Nam SM, Yi SS, Kwon HJ, Kang MS, Choi JH, Kim DW, Yoon YS, Hwang IK. Spatial and temporal changes in the PGE2 EP2 receptor in mice hippocampi during postnatal development and its relationship with cyclooxygenase-2. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2021; 24:908-913. [PMID: 34712420 PMCID: PMC8528246 DOI: 10.22038/ijbms.2021.56286.12556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 06/30/2021] [Indexed: 11/06/2022]
Abstract
Objective(s): Prostaglandin E2 E-prostanoid 2 receptor (PGE2 EP2), downstream of cyclooxygenase-2 (COX-2), plays an important role in inflammatory responses, but there are some reports about synaptic functions of COX-2 and PGE2 EP2 in the hippocampus. Materials and Methods: C57BL/6J mice were sacrificed at postnatal days (P) 1, 7, 14, 28, and 56 for immunohistochemical staining for EP2 and doublecortin as well as western blot for EP2. In addition, COX-2 knockout and its wild-type mice were euthanized for immunohistochemical staining for EP2. Results: EP2 immunoreactivity was observed in the majority of the cells in the dentate gyrus at P1 and P7, while at P14, it was detected in the outer granule cell layer and was confined to its subgranular zone at P28 and P56. EP2 protein levels in the hippocampal homogenates were also highest at P7 and lowest at P56. EP2 immunoreactivity was partially colocalized, with doublecortin (DCX)-immunoreactive neuroblasts appearing in the mid-zone of the granule cell layer at P14 and in the subgranular zone of the dentate gyrus at P28. Co-localization of EP2 and DCX was significantly decreased in the dentate gyrus in the P28 group compared with that in the P14 group. In COX-2 knockout mice, EP2 immunoreactivity was significantly decreased in the hippocampal CA1 region (P=0.000165) and dentate gyrus (P=0.00898). Conclusion: EP2 decreases with age, which is expressed in DCX-immunoreactive neuroblasts in the dentate gyrus. This suggests that EP2 is closely linked to structural lamination and adult neurogenesis in the dentate gyrus.
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Affiliation(s)
- Hyo Young Jung
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, Daejeon 34134, South Korea
| | - Woosuk Kim
- Department of Anatomy, College of Veterinary Medicine, and Veterinary Science Research Institute, Konkuk University, Seoul 05030, South Korea
| | - Kyu Ri Hahn
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, South Korea
| | - Sung Min Nam
- Department of Anatomy, School of Medicine, Wonkwang University, Iksan 54538, South Korea
| | - Sun Shin Yi
- Department of Biomedical Laboratory Science, College of Medical Sciences, Soonchunhyang University, Asan 31538, South Korea
| | - Hyun Jung Kwon
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung-Wonju National University, Gangneung 25457, South Korea
| | - Min Soo Kang
- Department of Anatomy, College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, South Korea
| | - Jung Hoon Choi
- Department of Anatomy, College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, South Korea
| | - Dae Won Kim
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung-Wonju National University, Gangneung 25457, South Korea
| | - Yeo Sung Yoon
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, South Korea
| | - In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, South Korea
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Cho HK, Kim W, Lee KY, Ahn JO, Choi JH, Hwang IK, Chung JY. Beta-nerve growth factor gene therapy alleviates pyridoxine-induced neuropathic damage by increasing doublecortin and tyrosine kinase A in the dorsal root ganglion. Neural Regen Res 2020; 15:162-168. [PMID: 31535665 PMCID: PMC6862420 DOI: 10.4103/1673-5374.264472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Beta-nerve growth factor (β-NGF) is known to be a major leading cause of neuronal plasticity. To identify the possible action mechanisms of β-NGF gene therapy for sciatic nerve recovery, experimental dogs were randomly divided into control, pyridoxine, and pyridoxine + β-NGF groups. We observed chronological changes of morphology in the dorsal root ganglia in response to pyridoxine toxicity based on cresyl violet staining. The number of large neurons positive for cresyl violet was dramatically decreased after pyridoxine intoxication for 7 days in the dorsal root ganglia and the neuron number was gradually increased after pyridoxine withdrawal. In addition, we also investigated the effects of β-NGF gene therapy on neuronal plasticity in pyridoxine-induced neuropathic dogs. To accomplish this, tyrosine kinase receptor A (TrkA), βIII-tubulin and doublecortin (DCX) immunohistochemical staining was performed at 3 days after the last pyridoxine treatment. TrkA-immunoreactive neurons were dramatically decreased in the pyridoxine group compared to the control group, but strong TrkA immunoreactivity was observed in the small-sized dorsal root ganglia in this group. TrkA immunoreactivity in the dorsal root ganglia was similar between β-NGF and control groups. The numbers of βIII-tubulin- and DCX-immunoreactive cells decreased significantly in the pyridoxine group compared to the control group. However, the reduction of βIII-tubulin- and DCX-immunoreactive cells in the dorsal root ganglia in the β-NGF group was significantly ameliorated than that in the pyridoxine group. These results indicate that β-NGF gene therapy is a powerful treatment of pyridoxine-induced neuropathic damage by increasing the TrkA and DCX levels in the dorsal root ganglia. The experimental protocol was approved by the Institutional Animal Care and Use Committee (IACUC) of Seoul National University, South Korea (approval No. SNU-060623-1, SNU-091009-1) on June 23, 2006 and October 9, 2009, respectively.
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Affiliation(s)
- Hyun-Kee Cho
- Department of Veterinary Internal Medicine and Institute of Veterinary Science, College of Veterinary Medicine, Kangwon National University, Chuncheon, Kangwon-do, South Korea
| | - Woosuk Kim
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, Research Institute for Veterinary Science, Seoul National University, Seoul, South Korea
| | - Kwon-Young Lee
- Department of Anatomy, College of Veterinary Medicine, Kangwon National University, Chuncheon, Kangwon-do, South Korea
| | - Jin-Ok Ahn
- Department of Veterinary Internal Medicine and Institute of Veterinary Science, College of Veterinary Medicine, Kangwon National University, Chuncheon, Kangwon-do, South Korea
| | - Jung Hoon Choi
- Department of Anatomy, College of Veterinary Medicine, Kangwon National University, Chuncheon, Kangwon-do, South Korea
| | - In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, Research Institute for Veterinary Science, Seoul National University, Seoul, South Korea
| | - Jin-Young Chung
- Department of Veterinary Internal Medicine and Institute of Veterinary Science, College of Veterinary Medicine, Kangwon National University, Chuncheon, Kangwon-do, South Korea
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Petrik D, Encinas JM. Perspective: Of Mice and Men - How Widespread Is Adult Neurogenesis? Front Neurosci 2019; 13:923. [PMID: 31555083 PMCID: PMC6727861 DOI: 10.3389/fnins.2019.00923] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/16/2019] [Indexed: 12/16/2022] Open
Abstract
These are exciting times for research on adult hippocampal neurogenesis (AHN). Debate and controversy regarding the existence of generation of new neurons in the adult, and even diseased human brain flourishes as articles against and in favor accumulate. Adult neurogenesis in the human brain is a phenomenon that does not share the qualities of quantum mechanics. The scientific community should agree that human AHN exists or does not, but not both at the same time. In this commentary, we discuss the latest research articles about hAHN and what their findings imply for the neurogenesis field.
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Affiliation(s)
- David Petrik
- School of Biosciences, Cardiff University, Cardiff, United Kingdom.,Institute of Stem Cell Research, Helmholtz Zentrum München, Munich, Germany.,Department of Physiological Genomics, Ludwig Maximilian University of Munich, Munich, Germany
| | - Juan M Encinas
- Laboratory of Neural Stem Cells and Neurogenesis, Achucarro Basque Center for Neuroscience, Leioa, Spain.,IKERBASQUE, The Basque Foundation for Science, Bilbao, Spain.,Department of Neurosciences, University of the Basque Country (UPV/EHU), Leioa, Spain
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6
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Gardini A, Taeymans O, Cherubini GB, de Stefani A, Targett M, Vettorato E. Linear magnetic resonance imaging measurements of the hippocampal formation differ in young versus old dogs. Vet Rec 2019; 185:306. [PMID: 31308154 PMCID: PMC6817983 DOI: 10.1136/vr.105243] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 06/11/2019] [Accepted: 06/23/2019] [Indexed: 12/13/2022]
Abstract
Age-related hippocampal formation (HF) atrophy has been documented on MRI studies using volumetric analysis and visual rating scales. This retrospective cross-sectional study aimed to compare linear MRI measurements of the HF between young (1–3 years) and old (>10 years) non-brachycephalic dogs, with normal brain anatomy and cerebrospinal fluid (CSF) analysis. Right and left hippocampal formation height (HFH), height of the brain (HB) and mean HFH/HB ratio were measured by two observers on a transverse T2 fluid-attenuated inversion recovery sequence containing rostral colliculi and mesencephalic aqueduct.119 MRI studies were enrolled: 75 young and 44 old dogs. Left and right HFH were greater (p<0.0001) in young, while HB was greater in old dogs (p=0.024). Mean HFH/HB ratio was 15.66 per cent and 18.30 per cent in old and young dogs (p<0.0001). No differences were found comparing measurements between epileptic and non-epileptic dogs. Old dogs have a greater HB; this may represent the different study populations or a statistical phenomenon. Ageing affects HF linear measurements. A reduction of mean HFH/HB ratio between 18.30 per cent and 15.66 per cent should be considered a physiological age-related process of the canine lifespan. The use of mean HFH/HB ratio could be considered for quantifying brain atrophy in elderly dogs.
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Affiliation(s)
- Anna Gardini
- Department of Neurology and Neurosurgery, Dick White Referrals, Six Mile Bottom, UK
| | - Olivier Taeymans
- Department of Diagnostic Imaging, Dick White Referrals, Six Mile Bottom, UK
| | | | - Alberta de Stefani
- Department of Neurology and Neurosurgery, Royal Veterinary College, London, UK
| | - Mike Targett
- Department of Neurology and Neurosurgery, University of Nottingham, Loughborough, UK
| | - Enzo Vettorato
- Department of Anaesthesia and Analgesia, Dick White Referrals, Six Mile Bottom, UK
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7
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Jung HY, Yoo DY, Kim JW, Kwon HJ, Lee KY, Choi JH, Kim DW, Chung JY, Yoon YS, Hwang IK. Age-associated alterations in constitutively expressed cyclooxygenase-2 immunoreactivity and protein levels in the hippocampus. Mol Med Rep 2017; 15:4333-4337. [PMID: 28487938 DOI: 10.3892/mmr.2017.6512] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 03/06/2017] [Indexed: 11/06/2022] Open
Abstract
Cyclooxygenase-2 (COX-2) is a known inducible inflammatory mediator. COX-2 is constitutively expressed in the hippocampus and may regulate synaptic plasticity. The present study investigated the age‑associated alterations in white blood cell counts and hippocampal COX‑2 expression in healthy mice using immunohistochemical and western blot analyses at 1 month postnatal (PM1), PM3, PM6, PM12 and PM24. White blood cell counts were significantly decreased in the PM24 group when compared with the PM1 group. In addition, lymphocyte counts were decreased in the PM24 group when compared with all other groups. By contrast, monocyte, neutrophil and eosinophil counts were increased in the PM24 group; however, this did not reach statistical significance. COX‑2 expression was identified in the granule cells of the dentate gyrus and in the pyramidal cells of the hippocampal CA2/3 region. COX‑2 immunoreactivity was maintained until PM18, however, the levels significantly decreased by PM24. These results suggest that, despite alterations in the differential white blood cell counts, the significant decrease in constitutive COX‑2 expression in the hippocampus may be associated with degenerative age-associated alterations in synaptic plasticity in the hippocampus.
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Affiliation(s)
- Hyo Young Jung
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Dae Young Yoo
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Jong Whi Kim
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - Hyun Jung Kwon
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung‑Wonju National University, Gangneung, Gangwon 25457, Republic of Korea
| | - Kwon Young Lee
- Department of Anatomy, College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Jung Hoon Choi
- Department of Anatomy, College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Dae Won Kim
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung‑Wonju National University, Gangneung, Gangwon 25457, Republic of Korea
| | - Jin Young Chung
- Department of Veterinary Internal Medicine and Geriatrics, College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Yeo Sung Yoon
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
| | - In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Republic of Korea
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8
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Youssef SA, Capucchio MT, Rofina JE, Chambers JK, Uchida K, Nakayama H, Head E. Pathology of the Aging Brain in Domestic and Laboratory Animals, and Animal Models of Human Neurodegenerative Diseases. Vet Pathol 2016; 53:327-48. [DOI: 10.1177/0300985815623997] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
According to the WHO, the proportion of people over 60 years is increasing and expected to reach 22% of total world’s population in 2050. In parallel, recent animal demographic studies have shown that the life expectancy of pet dogs and cats is increasing. Brain aging is associated not only with molecular and morphological changes but also leads to different degrees of behavioral and cognitive dysfunction. Common age-related brain lesions in humans include brain atrophy, neuronal loss, amyloid plaques, cerebrovascular amyloid angiopathy, vascular mineralization, neurofibrillary tangles, meningeal osseous metaplasia, and accumulation of lipofuscin. In aging humans, the most common neurodegenerative disorder is Alzheimer’s disease (AD), which progressively impairs cognition, behavior, and quality of life. Pathologic changes comparable to the lesions of AD are described in several other animal species, although their clinical significance and effect on cognitive function are poorly documented. This review describes the commonly reported age-associated neurologic lesions in domestic and laboratory animals and the relationship of these lesions to cognitive dysfunction. Also described are the comparative interspecies similarities and differences to AD and other human neurodegenerative diseases including Parkinson’s disease and progressive supranuclear palsy, and the spontaneous and transgenic animal models of these diseases.
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Affiliation(s)
- S. A. Youssef
- Department of Pathobiology, Dutch Molecular Pathology Center, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - M. T. Capucchio
- Department of Veterinary Sciences, Torino University, Torino, Italy
| | - J. E. Rofina
- Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - J. K. Chambers
- Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - K. Uchida
- Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - H. Nakayama
- Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - E. Head
- Sanders Brown Center on Aging, Pharmacology & Nutritional Sciences, University of Kentucky, Lexington, UK, USA
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9
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Zhang XM, Cai Y, Wang F, Wu J, Mo L, Zhang F, Patrylo PR, Pan A, Ma C, Fu J, Yan XX. Sp8 expression in putative neural progenitor cells in guinea pig and human cerebrum. Dev Neurobiol 2015; 76:939-55. [PMID: 26585436 DOI: 10.1002/dneu.22367] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 10/05/2015] [Accepted: 11/12/2015] [Indexed: 12/19/2022]
Abstract
Neural stem/progenitor cells have been characterized at neurogenic sites in adult mammalian brain with various molecular markers. Here it has been demonstrated that Sp8, a transcription factor typically expressed among mature GABAergic interneurons, also labels putative neural precursors in adult guinea pig and human cerebrum. In guinea pigs, Sp8 immunoreactive (Sp8+) cells were localized largely in the superficial layers of the cortex including layer I, as well as the subventricular zone (SVZ) and subgranular zone (SGZ). Sp8+ cells at the SGZ showed little colocalization with mature and immature neuronal markers, but co-expressed neural stem cell markers including Sox2. Some layer I Sp8+ cells also co-expressed Sox2. The amount of Sp8+ cells in the dentate gyrus was maintained 2 weeks after X-ray irradiation, while that of doublecortin (DCX+) cells was greatly reduced. Mild ischemic insult caused a transient increase of Sp8+ cells in the SGZ and layer I, with the subgranular Sp8+ cells exhibited an increased colabeling for the mitotic marker Ki67 and pulse-chased bromodeoxyuridine (BrdU). Sp8+ cells in the dentate gyrus showed an age-related decline in guinea pigs, in parallel with the loss of DCX+ cells in the same region. In adult humans, Sp8+ cells exhibited comparable morphological features as seen in guinea pigs, with those at the SGZ and some in cortical layer I co-expressed Sox2. Together, these results suggested that Sp8 may label putative neural progenitors in guinea pig and human cerebrum, with the labeled cells in the SGZ appeared largely not mitotically active under normal conditions. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 939-955, 2016.
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Affiliation(s)
- Xue-Mei Zhang
- Department of Neurology, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang, China
| | - Yan Cai
- Department of Anatomy and Neurobiology, Central South University School of Basic Medicine, Changsha, Hunan, China
| | - Fang Wang
- Department of Neurology, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang, China
| | - Jun Wu
- Department of Neurology, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang, China
| | - Lin Mo
- Department of Neurology, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang, China
| | - Feng Zhang
- Department of Radiation Oncology, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang, China
| | - Peter R Patrylo
- Southern Illinois University School of Medicine, Center for Integrated Research in Cognitive and Neural Sciences, Carbondale, Illinois
| | - Aihua Pan
- Department of Anatomy and Neurobiology, Central South University School of Basic Medicine, Changsha, Hunan, China
| | - Chao Ma
- Department of Human Anatomy, Histology & Embryology, Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Jin Fu
- Department of Neurology, The Second Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang, China
| | - Xiao-Xin Yan
- Department of Anatomy and Neurobiology, Central South University School of Basic Medicine, Changsha, Hunan, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Changsha, Hunan, China
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10
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Amrein I. Adult hippocampal neurogenesis in natural populations of mammals. Cold Spring Harb Perspect Biol 2015; 7:7/5/a021295. [PMID: 25934014 DOI: 10.1101/cshperspect.a021295] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This review will discuss adult hippocampal neurogenesis in wild mammals of different taxa and outline similarities with and differences from laboratory animals. It begins with a review of evidence for hippocampal neurogenesis in various mammals, and shows the similar patterns of age-dependent decline in cell proliferation in wild and domesticated mammals. In contrast, the pool of immature neurons that originate from proliferative activity varies between species, implying a selective advantage for mammals that can make use of a large number of these functionally special neurons. Furthermore, rapid adaptation of hippocampal neurogenesis to experimental challenges appears to be a characteristic of laboratory rodents. Wild mammals show species-specific, rather stable hippocampal neurogenesis, which appears related to demands that characterize the niche exploited by a species rather than to acute events in the life of its members. Studies that investigate adult neurogenesis in wild mammals are not numerous, but the findings of neurogenesis under natural conditions can provide new insights, and thereby also address the question to which cognitive demands neurogenesis may respond during selection.
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Affiliation(s)
- Irmgard Amrein
- Institute of Anatomy, University of Zürich-Irchel, CH-8057 Zürich, Switzerland
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11
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Takamori Y, Wakabayashi T, Mori T, Kosaka J, Yamada H. Organization and cellular arrangement of two neurogenic regions in the adult ferret (Mustela putorius furo) brain. J Comp Neurol 2014; 522:1818-38. [PMID: 24214369 DOI: 10.1002/cne.23503] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 10/29/2013] [Accepted: 11/01/2013] [Indexed: 01/03/2023]
Abstract
In the adult mammalian brain, two neurogenic regions have been characterized, the subventricular zone (SVZ) of the lateral ventricle (LV) and the subgranular zone (SGZ) of the dentate gyrus (DG). Despite remarkable knowledge of rodents, the detailed arrangement of neurogenic regions in most mammals is poorly understood. In this study, we used immunohistochemistry and cell type-specific antibodies to investigate the organization of two germinal regions in the adult ferret, which belongs to the order Carnivora and is widely used as a model animal with a gyrencephalic brain. From the SVZ to the olfactory bulb, doublecortin-positive cells tended to organize in chain-like clusters, which are surrounded by a meshwork of astrocytes. This structure is homologous to the rostral migratory stream (RMS) described in other species. Different from rodents, the horizontal limb of the RMS emerges directly from the LV, and the anterior region of the LV extends rostrally and reached the olfactory bulb. In the DG, glial fibrillary acidic protein-positive cells with long radial processes as well as doublecortin-positive cells are oriented in the SGZ. In both regions, doublecortin-positive cells showed characteristic morphology and were positive for polysialylated-neural cell adhesion molecule, beta-III tubulin, and lamin B1 (intense staining). Proliferating cells were detected in both regions using antibodies against proliferating cell nuclear antigen and phospho-histone H3. These observations demonstrate that the two neurogenic regions in ferrets have a similar cellular composition as those of other mammalian species despite anatomical differences in the brain.
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Affiliation(s)
- Yasuharu Takamori
- Department of Anatomy and Cell Science, Kansai Medical University, Osaka, 573-1010, Japan
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12
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Olude AM, Olopade JO, Ihunwo AO. Adult neurogenesis in the African giant rat (Cricetomysgambianus, waterhouse). Metab Brain Dis 2014; 29:857-66. [PMID: 24577632 DOI: 10.1007/s11011-014-9512-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 02/13/2014] [Indexed: 12/17/2022]
Abstract
African giant rats (AGR) are large nocturnal rodents with well-developed olfactory abilities uniquely linked to cognition. The post natal proliferation of neurons (adult neurogenesis), is thought to play an important role in spatial memory and learning. Eighteen brains of the African giant rats (Cricetomys gambianus, Waterhouse) belonging to three age groups (neonates n = 6, juveniles n = 6 and adults n = 6) were examined by immunohistochemistry, using antibodies for proliferating cells (Ki-67), and immature neurons (Doublecortin, DCX). Mean brain weights were 0.40 ± 0.00 g; 4.48 ± 0.43 g and 5.48 ± 0.56 g for neonate, juvenile and adult brains respectively. Our results show positive cell proliferation in the subventricular (SVZ) zone of the lateral ventricle and in the dentate gyrus (DG) of the hippocampus but at low levels in adults compared to juveniles. Estimate of the mean total proliferative Ki-67 positive cells in the SVZ and DG in the neonates was 21145 ± 8395, and 11800 ± 1230; brains from juvenile AGRs, 45530 ± 13950 and 12480 ± 7860 and from adult brains, (6880 ± 340 and 1130 ± 150) respectively. Juvenile AGR in particular, stained positively in potential sites such as the piriform and somatosensory cortices, striatum and cerebellum. This intensity of the proliferating cells within the dentate gyrus in the juvenile and adult brains could be associated with a role in the cognitive functions of landmine detection and tuberculosis diagnosis after olfactory training of the African giant rat. The juvenile rats are proposed as the most suited for experimental research and olfactory training.
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Affiliation(s)
- Ayo Mathew Olude
- School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, South Africa
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13
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Adeosun SO, Hou X, Zheng B, Stockmeier C, Ou X, Paul I, Mosley T, Weisgraber K, Wang JM. Cognitive deficits and disruption of neurogenesis in a mouse model of apolipoprotein E4 domain interaction. J Biol Chem 2013; 289:2946-59. [PMID: 24324264 DOI: 10.1074/jbc.m113.497909] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apolipoprotein E4 (apoE4) allele is the major genetic risk factor for sporadic Alzheimer disease (AD) due to the higher prevalence and earlier onset of AD in apoE4 carriers. Accumulating data suggest that the interaction between the N- and the C-terminal domains in the protein may be the main pathologic feature of apoE4. To test this hypothesis, we used Arg-61 mice, a model of apoE4 domain interaction, by introducing the domain interaction feature of human apoE4 into native mouse apoE. We carried out hippocampus-dependent learning and memory tests and related cellular and molecular assays on 12- and 3-month-old Arg-61 and age-matched background C57BL/6J mice. Learning and memory task performance were impaired in Arg-61 mice at both old and young ages compared with C57BL/6J mice. Surprisingly, young Arg-61 mice had more mitotic doublecortin-positive cells in the subgranular zone; mRNA levels of brain-derived neurotrophic factor (BDNF) and TrkB were also higher in 3-month-old Arg-61 hippocampus compared with C57BL/6J mice. These early-age neurotrophic and neurogenic (proliferative) effects in the Arg-61 mouse may be an inadequate compensatory but eventually detrimental attempt by the system to "repair" itself. This is supported by the higher cleaved caspase-3 levels in the young animals that not only persisted, but increased in old age, and the lower levels of doublecortin at old age in the hippocampus of Arg-61 mice. These results are consistent with human apoE4-dependent cognitive and neuro-pathologic changes, supporting the principal role of domain interaction in the pathologic effect of apoE4. Domain interaction is, therefore, a viable therapeutic/prophylactic target for cognitive impairment and AD in apoE4 subjects.
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Brus M, Keller M, Lévy F. Temporal features of adult neurogenesis: differences and similarities across mammalian species. Front Neurosci 2013; 7:135. [PMID: 23935563 PMCID: PMC3732872 DOI: 10.3389/fnins.2013.00135] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 07/13/2013] [Indexed: 01/01/2023] Open
Abstract
Production of new neurons continues throughout life in most invertebrates and vertebrates like crustaceans, fishes, reptiles, birds, and mammals including humans. Most studies have been carried out on rodent models and demonstrated that adult neurogenesis is located mainly in two structures, the dentate gyrus (DG) of the hippocampus and the sub-ventricular zone (SVZ). If adult neurogenesis is well preserved throughout evolution, yet there are however some features which differ between species. The present review proposes to target similarities and differences in the mechanism of mammalian adult neurogenesis by comparing selected species including humans. We will highlight the cellular composition and morphological organization of the SVZ in primates which differs from that of rodents and may be of functional relevance. We will particularly focus on the dynamic of neuronal maturation in rodents, primates, and humans but also in sheep which appears to be an interesting model due to its similarities with the primate brain.
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Affiliation(s)
- Maïna Brus
- INRA, UMR 85, Physiologie de la Reproduction et des Comportements Nouzilly, France ; CNRS, UMR 7247 Nouzilly, France ; Université de Tours Tours, France ; Haras Nationaux Nouzilly, France ; Laboratory of Behavioral Neuroendocrinology, GIGA Neurosciences, University of Liège Liège, Belgium
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15
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Head E. A canine model of human aging and Alzheimer's disease. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1384-9. [PMID: 23528711 DOI: 10.1016/j.bbadis.2013.03.016] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 03/15/2013] [Accepted: 03/17/2013] [Indexed: 12/22/2022]
Abstract
The aged dog naturally develops cognitive decline in many different domains (including learning and memory) but also exhibits human-like individual variability in the aging process. The neurobiological basis for cognitive dysfunction may be related to structural changes that reflect neurodegeneration. Molecular cascades that contribute to degeneration in the aging dog brain include the progressive accumulation of beta-amyloid (Aβ) in diffuse plaques and in the cerebral vasculature. In addition, neuronal dysfunction occurs as a consequence of mitochondrial dysfunction and cumulative oxidative damage. In combination, the aged dog captures key features of human aging, making them particularly useful for the development of preventive or therapeutic interventions to improve aged brain function. These interventions can then be translated into human clinical trials. This article is part of a Special Issue entitled: Animal Models of Disease.
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Affiliation(s)
- Elizabeth Head
- Department of Molecular and Biomedical Pharmacology, University of Kentucky, Lexington, KY 40536, USA.
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16
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Wohlsein P, Deschl U, Baumgärtner W. Nonlesions, unusual cell types, and postmortem artifacts in the central nervous system of domestic animals. Vet Pathol 2012; 50:122-43. [PMID: 22692622 DOI: 10.1177/0300985812450719] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In the central nervous system (CNS) of domestic animals, numerous specialized normal structures, unusual cell types, findings of uncertain or no significance, artifacts, and various postmortem alterations can be observed. They may cause confusion for inexperienced pathologists and those not specialized in neuropathology, leading to misinterpretations and wrong diagnoses. Alternatively, changes may mask underlying neuropathological processes. "Specialized structures" comprising the hippocampus and the circumventricular organs, including the vascular organ of the lamina terminalis, subfornical organ, subcommissural organ, pineal gland, median eminence/neurohypophyseal complex, choroid plexus, and area postrema, are displayed. Unusual cell types, including cerebellar external germinal cells, CNS progenitor cells, and Kolmer cells, are presented. In addition, some newly recognized cell types as of yet incompletely understood significance and functionality, such as synantocytes and aldynoglia, are introduced and described. Unusual reactive astrocytes in cats, central chromatolysis, neuronal vacuolation, spheroids, spongiosis, satellitosis, melanosis, neuromelanin, lipofuscin, polyglucosan bodies, and psammoma bodies may represent incidental findings of uncertain or no significance and should not be confused with significant microscopic changes. Auto- and heterolysis as well as handling and histotechnological processing may cause postmortem morphological changes of the CNS, including vacuolization, cerebellar conglutination, dark neurons, Buscaino bodies, freezing, and shrinkage artifacts, all of which have to be differentiated from genuine lesions. Postmortem invasion of micro-organisms should not be confused with intravital infections. Awareness of these different changes and their recognition are a prerequisite for identifying genuine lesions and may help to formulate a professional morphological and etiological diagnosis.
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Affiliation(s)
- P Wohlsein
- Department of Pathology, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany.
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17
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Yoo DY, Kim W, Lee CH, Shin BN, Nam SM, Choi JH, Won MH, Yoon YS, Hwang IK. Melatonin improves D-galactose-induced aging effects on behavior, neurogenesis, and lipid peroxidation in the mouse dentate gyrus via increasing pCREB expression. J Pineal Res 2012; 52:21-8. [PMID: 21718363 DOI: 10.1111/j.1600-079x.2011.00912.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Melatonin (N-acetyl-5-methoxytryptamine) has multiple functions. In this study, we investigated the effects of melatonin on memory, cell proliferation, and neuroblast differentiation in the dentate gyrus of a mouse model of D-galactose-induced aging. D-galactose was subcutaneously administered to 7-wk-old mice for 10 wk, and age-matched mice were used as controls. Seven weeks after D-galactose administration, vehicle (water) or melatonin (6 mg/L in water) was administered ad libitum to the mice for 3 wk. The administration of D-galactose significantly increased the escape latency compared with that in the control mice on days 1-3. In addition, cells in the subgranular zone and in the granule cell layer of the dentate gyrus showed severe damage (cytoplasmic condensation) in the D-galactose-treated mice. However, melatonin supplementation to these mice for 3 wk significantly ameliorated the D-galactose-induced increase in escape latency and neuronal damage compared with the vehicle-treated group. The administration of melatonin also significantly restored the D-galactose-induced reduction of proliferating cells (Ki67-positive cells) and differentiating neuroblasts (doublecortin-positive neuroblasts) in the dentate gyrus. Furthermore, the administration of melatonin significantly increased Ser133-phosphorylated cyclic AMP response element binding protein in the dentate gyrus. The administration of melatonin significantly reduced D-galactose-induced lipid peroxidation in the dentate gyrus. These results suggest that melatonin may be helpful in reducing age-related phenomena in the brain.
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Affiliation(s)
- Dae Young Yoo
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul, South Korea
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18
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Yoo DY, Kim W, Kim IH, Nam SM, Chung JY, Choi JH, Yoon YS, Won MH, Hwang IK. Combination effects of sodium butyrate and pyridoxine treatment on cell proliferation and neuroblast differentiation in the dentate gyrus of D-galactose-induced aging model mice. Neurochem Res 2011; 37:223-31. [PMID: 21984169 DOI: 10.1007/s11064-011-0597-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 09/08/2011] [Indexed: 02/06/2023]
Abstract
We previously reported that sodium butyrate (SB), a histone deacetylase inhibitor, robustly increased pyridoxine-induced cell proliferation and neuroblast differentiation in the dentate gyrus of the adult mouse. In this study, we investigated the effects of treatment with SB combined with pyridoxine on cell proliferation and neuroblast differentiation in the dentate gyrus of a mouse model of aging induced by D: -galactose (D: -gal). D: -gal was administered to 20-week-old male mice (D: -gal mice) for 10 weeks to induce changes that resemble natural aging in animals. Seven weeks after D: -gal (100 mg/kg) treatment, vehicle (physiological saline; D: -gal-vehicle mice) and SB (300 mg/kg) combined with pyridoxine (Pyr; 350 mg/kg) were administered to the mice (D: -gal-Pyr-SB mice) for 3 weeks. Escape latency under water maze in the D: -gal mice was longer than that in the control mice. In the D: -gal-Pyr-SB mice, escape latency was similar to that in the control mice. In the D: -gal mice, many cells in the granule cell layer of the dentate gyrus showed pyknosis and condensation of the cytoplasm. However, in the D: -gal-Pyr-SB mice, such cellular changes were rarely found. Furthermore, the D: -gal mice showed a great reduction in cell proliferation (Ki67-positive cells) and neuroblast differentiation (doublecortin-positive neuroblasts) in the dentate gyrus compared to control mice. However, in the D: -gal-Pyr-SB mice, cell proliferation and neuroblast differentiation were markedly increased in the dentate gyrus. Furthermore, the administration of pyridoxine with sodium butyrate significantly increased Ser133-phosphorylated cyclic AMP response element binding protein in the dentate gyrus. These results indicate that the combination treatment of Pyr with SB in D: -gal mice ameliorated the D: -gal-induced reduction in cell proliferation, neuroblast differentiation, and memory deficits.
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Affiliation(s)
- Dae Young Yoo
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, South Korea
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19
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Petrik D, Lagace DC, Eisch AJ. The neurogenesis hypothesis of affective and anxiety disorders: are we mistaking the scaffolding for the building? Neuropharmacology 2011; 62:21-34. [PMID: 21945290 DOI: 10.1016/j.neuropharm.2011.09.003] [Citation(s) in RCA: 179] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 09/03/2011] [Accepted: 09/06/2011] [Indexed: 01/22/2023]
Abstract
Hypotheses are scaffoldings erected in front of a building and then dismantled when the building is finished. They are indispensable for the workman; but you mustn't mistake the scaffolding for the building. Johann Wolfgang von Goethe. The neurogenesis hypothesis of affective disorders - in its simplest form - postulates that the generation of neurons in the postnatal hippocampal dentate gyrus is involved in the etiology and treatment efficacy of major depressive disorder (MDD). The hypothesis was established in the 1990s but was built on a broad foundation of earlier research on the hippocampus, serotonin and MDD. It has gone through several growth phases fueled by discoveries both correlative and causative in nature. Recently, the hypothesis has also been broadened to also include potential relevance for anxiety disorders, like post-traumatic stress disorder (PTSD). As any hypothesis should be, it has been tested and challenged, sometimes vigorously. Here we review the current standing of the neurogenesis hypothesis of affective and anxiety disorders, noting in particular how a central postulate - that decreased neurogenesis results in depression or anxiety - has, in general, been rejected. We also review the controversies on whether treatments for these disorders, like antidepressants, rely on intact neurogenesis for their efficacy, and the existence of neurogenesis-dependent and -independent effects of antidepressants. In addition, we review the implications that the hypothesis has for the response to stress, PTSD, and the neurobiology of resilience, and highlight our own work showing that adult-generated neurons are functionally important for the behavioral response to social stress. We conclude by emphasizing how advancements in transgenic mouse technology, rodent behavioral analyses, and our understanding of the neurogenesis process will allow us to refine our conclusions and perform ever more specific experiments. Such scrutiny is critical, since if we "mistake the scaffolding for the building" we could overlook opportunities for translational impact in the clinic. This article is part of a special Issue entitled 'Anxiety and Depression'.
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Affiliation(s)
- David Petrik
- Department of Psychiatry, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9070, USA
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20
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Head E. Neurobiology of the aging dog. AGE (DORDRECHT, NETHERLANDS) 2011; 33:485-496. [PMID: 20845082 PMCID: PMC3168593 DOI: 10.1007/s11357-010-9183-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Accepted: 09/02/2010] [Indexed: 05/29/2023]
Abstract
Aged canines naturally accumulate several types of neuropathology that may have links to cognitive decline. On a gross level, significant cortical atrophy occurs with age along with an increase in ventricular volume based on magnetic resonance imaging studies. Microscopically, there is evidence of select neuron loss and reduced neurogenesis in the hippocampus of aged dogs, an area critical for intact learning and memory. The cause of neuronal loss and dysfunction may be related to the progressive accumulation of toxic proteins, oxidative damage, cerebrovascular pathology, and changes in gene expression. For example, aged dogs naturally accumulate human-type beta-amyloid peptide, a protein critically involved with the development of Alzheimer's disease in humans. Further, oxidative damage to proteins, DNA/RNA and lipids occurs with age in dogs. Although less well explored in the aged canine brain, neuron loss, and cerebrovascular pathology observed with age are similar to human brain aging and may also be linked to cognitive decline. Interestingly, the prefrontal cortex appears to be particularly vulnerable early in the aging process in dogs and this may be reflected in dysfunction in specific cognitive domains with age.
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Affiliation(s)
- Elizabeth Head
- Sanders-Brown Center on Aging, Department of Molecular and Biomedical Pharmacology, University of Kentucky, 800 South Limestone Street, Lexington, KY 40536, USA.
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21
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Schoenfeld TJ, Gould E. Stress, stress hormones, and adult neurogenesis. Exp Neurol 2011; 233:12-21. [PMID: 21281629 DOI: 10.1016/j.expneurol.2011.01.008] [Citation(s) in RCA: 263] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 01/18/2011] [Accepted: 01/24/2011] [Indexed: 01/17/2023]
Abstract
The dentate gyrus of the hippocampus continues to produce new neurons throughout adulthood. Adult neurogenesis has been linked to hippocampal function, including learning and memory, anxiety regulation and feedback of the stress response. It is thus not surprising that stress, which affects hippocampal function, also alters the production and survival of new neurons. Glucocorticoids, along with other neurochemicals, have been implicated in stress-induced impairment of adult neurogenesis. Paradoxically, increases in corticosterone levels are sometimes associated with enhanced adult neurogenesis in the dentate gyrus. In these circumstances, the factors that buffer against the suppressive influence of elevated glucocorticoids remain unknown; their discovery may provide clues to reversing pathological processes arising from chronic exposure to aversive stress.
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Affiliation(s)
- Timothy J Schoenfeld
- Department of Psychology, Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA
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22
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Comparison of ionized calcium-binding adapter molecule 1-immunoreactive microglia in the spinal cord between young adult and aged dogs. Neurochem Res 2010; 35:620-7. [PMID: 20012688 DOI: 10.1007/s11064-009-0108-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Microglia are main form of active immune defense, and they are constantly moving and analyzing the CNS for damaged neurons and infectious agents. In this study, we compared microglia in the spinal cord of the young adult (1-2 years old) and aged (10-12 years old) German Shepherd dogs via immunohistochemistry and western blot analysis for ionized calcium-binding adapter molecule 1 (Iba-1), a microglial marker. In addition, we also observed the interferon-gamma (IFN-gamma), a pro-inflammatory cytokine, and interleukin-1beta (IL-1beta), produced by activated microglia/macrophage, protein levels in these groups. At first, we found that neuronal nuclei (NeuN, a neuronal marker)-immunoreactive neurons were distributed throughout the grey mate of the spinal cord, and there were no significant differences between the adult and aged groups. Most of Iba-1-immunoreactive microglia were morphologically ramified microglia (resting form) in the adult group, while some Iba-1-immunoreactive microglia were morphologically activated microglia in the aged group. In western blot analysis, Iba-1, IFN-gamma and IL-1beta expression were increased in the aged group. This result may be associated with age-dependent changes in the spinal cord.
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23
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Cannabinoids attenuate the effects of aging upon neuroinflammation and neurogenesis. Neurobiol Dis 2009; 34:300-7. [DOI: 10.1016/j.nbd.2009.01.014] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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Ghi P, Di Brisco F, Dallorto D, Osella MC, Orsetti M. Age-related modifications of egr1 expression and ubiquitin-proteasome components in pet dog hippocampus. Mech Ageing Dev 2009; 130:320-7. [PMID: 19428450 DOI: 10.1016/j.mad.2009.01.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Revised: 01/20/2009] [Accepted: 01/23/2009] [Indexed: 11/17/2022]
Abstract
In this paper we examined the impact of age on cognitive functions and the age-related modifications of egr1 expression, an inducible transcription factor with a confirmed role in synaptic plasticity and regulation of the proteasome activity, on pet dogs. Additionally, we examined the age-related changes of some elements of the ubiquitin-proteasome system, which is the apparatus that prevents the intracellular accumulation of abnormal proteins. The results of behavioral analysis revealed that old/senior dogs (9-16-year-old) had impaired cognitive performance compared to young/middle-aged dogs (2-8-year-old) in the Reversal Learning task. Taken togheter, the results (age-related decline of Psmd4, Psmb8, CHIP, and egr1 expression; increase of Psmb9 and Hsp90 expression) suggest that the activity of the ubiquitin-proteasome system in the dog hippocampus is a multi-step process, in which abnormal proteins destined for degradation are recognized and destroyed, and shows an age-related decline. The consequent failure of the "protein quality control system" might have detrimental effects on cell physiology and lead to a progressive impairment of cognitive functions.
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Affiliation(s)
- Piera Ghi
- Dipartimento di Anatomia, Farmacologia e Medicina Legale, Università degli Studi di Torino, C.so Raffaello 33, 10125 Torino, Italy.
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25
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HWANG IK, YOO KY, PARK OK, CHOI JH, LEE CH, WON MH. Comparison of Density and Morphology of Neuroblasts in the Dentate Gyrus among Variously Aged Dogs, German Shepherds. J Vet Med Sci 2009; 71:211-5. [DOI: 10.1292/jvms.71.211] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- In Koo HWANG
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and BK21 Program for Veterinary Science, Seoul National University
| | - Ki-Yeon YOO
- Department of Anatomy and Neurobiology, College of Medicine, Hallym University
| | - Ok Kyu PARK
- Department of Anatomy and Neurobiology, College of Medicine, Hallym University
| | - Jung Hoon CHOI
- Department of Anatomy and Neurobiology, College of Medicine, Hallym University
| | - Choong Hyun LEE
- Department of Anatomy and Neurobiology, College of Medicine, Hallym University
| | - Moo-Ho WON
- Department of Anatomy and Neurobiology, College of Medicine, Hallym University
- Institute of Neurodegeneration and Neuroregeneration, Hallym University
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Hwang IK, Yoon YS, Choi JH, Yoo KY, Yi SS, Chung DW, Kim HJ, Kim CS, DO SG, Seong JK, Lee IS, Won MH. Doublecortin-immunoreactive neuronal precursors in the dentate gyrus of spontaneously hypertensive rats at various age stages: comparison with Sprague-Dawley rats. J Vet Med Sci 2008; 70:373-7. [PMID: 18460832 DOI: 10.1292/jvms.70.373] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Spontaneously hypertensive rats (SHRs) are widely accepted in medical research because this model has been used for studies in neurodegenerative diseases such as vascular dementia and stroke. In the present study, we observed newly generated neuronal precursors using doublecortin (DCX, a marker of neural proliferation and differentiation) in the subgranular zone of the dentate gyrus in SHRs compared to Sprague-Dawley rats (SDRs) at various age stages. DCX immunoreactivity, immunoreactive cell numbers and its protein level in the dentate gyrus of the SHRs were higher than those in the SDRs at postnatal month 1 (PM 1). At PM 8, DCX immunoreactivity, immunoreactive cell numbers and protein levels in both groups were markedly decreased compared to those at PM 1; however, they were higher than those in the SDRs. They were decreased in the both groups with age: DCX immunoreactive cells in the SDRs were few at PM 12. Our results indicate that newly generated neuronal precursors are more abundant in SHRs than in SDRs during their life.
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Affiliation(s)
- In Koo Hwang
- Department of Anatomy, College of Veterinary Medicine and School of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
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27
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Darmopil S, Petanjek Z, Mohammed AH, Bogdanović N. Environmental enrichment alters dentate granule cell morphology in oldest-old rat. J Cell Mol Med 2008; 13:1845-1856. [PMID: 19175692 DOI: 10.1111/j.1582-4934.2008.00560.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The hippocampus of aged rats shows marked age-related morphological changes that could cause memory deficits. Experimental evidence has established that environmental enrichment attenuates memory deficits in aged rats. We therefore studied whether environmental enrichment produces morphological changes on the dentate granule cells of aged rats. Fifteen male Sprague-Dawley rats, 24 months of age, were randomly distributed in two groups that were housed under standard (n = 7) or enriched (n = 8) environmental conditions for 26 days. Quantitative data of dendritic morphology from dentate gyrus granule cells were obtained on Golgi-Cox stained sections. Environmental enrichment significantly increased the complexity and size of dendritic tree (total number of segments increased by 61% and length by 116%), and spine density (88% increase). There were large interindividual differences within the enriched group, indicating differential individual responses to environmental stimulation. Previous studies in young animals have shown changes produced by environmental enrichment in the morphology of dentate gyrus granule cells. The results of the present study show that environmental enrichment can also produce changes in dentate granule cell morphology in the senescent brain. In conclusion, the hippocampus retains its neuroplastic capacity during aging, and enriched environmental housing conditions can attenuate age-related dendritic regression and synaptic loss, thus preserving memory functions.
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Affiliation(s)
- Sanja Darmopil
- Department for Neurobiology, Caring Science and Society, Division of Clinical Geriatrics, Karolinska Institutet Science Park, Novum Research Park, Stockholm, Sweden.,Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Šalata, Zagreb, Croatia
| | - Zdravko Petanjek
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Šalata, Zagreb, Croatia.,Department of Anatomy, School of Medicine, University of Zagreb, Šalata, Zagreb, Croatia
| | - Abdul H Mohammed
- Department for Neurobiology, Caring Science and Society, Division of Clinical Geriatrics, Karolinska Institutet Science Park, Novum Research Park, Stockholm, Sweden.,School of Social Sciences, Växjö University, Växjö, Sweden
| | - Nenad Bogdanović
- Department for Neurobiology, Caring Science and Society, Division of Clinical Geriatrics, Karolinska Institutet Science Park, Novum Research Park, Stockholm, Sweden.,Wyeth Pharmaceutical, Global Medical Team - Neuroscience, Maidenhead, London, UK
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28
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Strain-specific differences in cell proliferation and differentiation in the dentate gyrus of C57BL/6N and C3H/HeN mice fed a high fat diet. Brain Res 2008; 1241:1-6. [PMID: 18761331 DOI: 10.1016/j.brainres.2008.08.024] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 07/22/2008] [Accepted: 08/05/2008] [Indexed: 11/23/2022]
Abstract
The authors investigated strain-specific cell proliferation and differentiation differences in the dentate gyri of C57BL/6N (susceptible strain to obesity) and C3H/HeN (resistant strain to obesity) mice. In addition, the influences of a high fat diet (HD) on neuronal differentiation in C57BL/6N and C3H/HeN mice fed a low-fat diet (LD) or HD for 4 or 12 weeks were investigated. Body weight and body weight gains were significantly higher in HD-fed C57BL/6N and C3H/HeN mice than in LD-fed C57BL/6N and C3H/HeN mice. In particular, body weight gains were significantly higher in C57BL/6N mice than in C3H/HeN mice. In both of HD- and LD-fed C57BL/6N and C3H/HeN mice for 4 weeks, some Ki67 and many DCX immunoreactive cells were detected in the subgranular zone of the dentate gyrus. In HD-fed C57BL/6N and C3H/HeN mice, the number of Ki67 immunoreactive cells and DCX immunoreactivities in the dentate gyri were significantly lower than in LD-fed C57BL/6N and C3H/HeN mice. However, the number of Ki67 immunoreactive cells and DCX immunoreactivities in HD-fed C57BL/6N mice were significantly lower than in HD-fed C3H/HeN mice. These results suggest that C57BL/6N mice are more vulnerable to HD induced obesity than C3H/HeN mice. In addition, the feeding of HD was found to exacerbate reduced cell proliferation and differentiation in the dentate gyri of C57BL/6N mice as compared with that in C3H/HeN mice.
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Hwang IK, Yoo KY, Yi SS, Kwon YG, Ahn YK, Seong JK, Lee IS, Yoon YS, Won MH. Age-related differentiation in newly generated DCX immunoreactive neurons in the subgranular zone of the gerbil dentate gyrus. Neurochem Res 2007; 33:867-72. [PMID: 17987384 DOI: 10.1007/s11064-007-9528-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Accepted: 10/05/2007] [Indexed: 01/17/2023]
Abstract
In the present study, we investigated age-related changes of newborn neurons in the gerbil dentate gyrus using doublecortin (DCX), a marker of neuronal progenitors which differentiate into neurons in the brain. In the postnatal month 1 (PM 1) group, DCX immunoreactivity was detected in the subgranular zone of the dentate gyrus, but DCX immunoreactive neurons did not have fully developed processes. Thereafter, DCX immunoreactivity and its protein levels in the dentate gyrus were found to decrease with age. Between PM 3 and PM 18, DCX immunoreactive neuronal progenitors showed well-developed processes which projected to the granular layer of the dentate gyrus, but at PM 24, a few DCX immunoreactive neuronal progenitors were detected in the subgranular zone of the dentate gyrus. DCX protein level in the dentate gyrus at PM 1 was high, thereafter levels of DCX were decreased with time. The authors suggest that a decrease of DCX immunoreactivity and its protein level with age may be associated with aging processes in the hippocampal dentate gyrus.
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Affiliation(s)
- In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and BK21 Program for Veterinary Science, Seoul National University, Seoul 151-742, South Korea
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30
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Choi JH, Hwang IK, Lee CH, Chung DW, Yoo KY, Li H, Won MH, Seong JK, Yoon YS, Lee IS. Immunoreactivities and levels of mineralocorticoid and glucocorticoid receptors in the hippocampal CA1 region and dentate gyrus of adult and aged dogs. Neurochem Res 2007; 33:562-8. [PMID: 17985238 DOI: 10.1007/s11064-007-9479-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Accepted: 08/15/2007] [Indexed: 11/29/2022]
Abstract
Corticosteroids are important factors in the maintenance of homeostasis in the brain. They are regulated via the interaction with two corticosteroid receptor systems-the mineralocorticoid (MR) and glucocorticoid receptor (GR). In the present study, we observed age-related changes in serum cortisol levels, and immunoreactivities and protein levels of MR and GR in the hippocampal CA1 region and dentate gyrus. The serum cortisol levels were significantly high (about twofold) in the aged group compared to that in the adult group. In the adult dog (2-3 years old), MR and GR immunoreactivity was detected in neurons in the pyramidal layer of the CA1 region, and in the granular and multiform layers of the dentate gyrus. In the aged dog (10-12 years old), MR immunoreactivity in the CA1 region was significantly decreased, especially, in the dentate multiform layer. In contrast, GR immunoreactivity in the aged dog was slightly decreased in the CA1 region and dentate gyrus. In the Western blot analysis, MR protein level in the aged dog was significantly lower compared to that of the adult dog; GR protein level in the aged dog was not significantly decreased. This result indicates that the reduction of MR immunoreactivity and protein level in the hippocampus of the aged dog may be associated with neural dysfunction in the aged hippocampus.
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Affiliation(s)
- Jung Hoon Choi
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, South Korea
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31
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Hwang IK, Yi SS, Kim YN, Kim IY, Lee IS, Yoon YS, Seong JK. Reduced hippocampal cell differentiation in the subgranular zone of the dentate gyrus in a rat model of type II diabetes. Neurochem Res 2007; 33:394-400. [PMID: 17712629 DOI: 10.1007/s11064-007-9440-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Accepted: 07/09/2007] [Indexed: 11/30/2022]
Abstract
It has recently been reported that diabetes mellitus is strongly associated with neurodegenerative and functional disorders of the central nervous system. In the present study, we investigated the changes in proliferating neurons in the dentate gyrus of type II diabetic rats using doublecortin (DCX), a marker of progenitors differentiating into neurons. At 4 weeks after birth, there were no differences in the blood glucose levels of Zucker diabetic fatty (ZDF) rats or Zucker lean control (ZLC) rats. DCX-immunoreactive neurons were detectable in the subgranular zone of the dentate gyrus in both the ZDF and ZLC rats; however, DCX immunoreactivity was higher in the ZLC rats than in the ZDF rats. At 12 weeks after birth, the blood glucose level was significantly increased by 400 mg/dl in the ZDF rats, but the blood glucose level in the ZLC rats was only slightly increased by 152.3 mg/dl. DCX immunoreactivity was significantly decreased in 12-week-old rats in comparison to 4-week-old rats. Some DCX-immunoreactive neurons were detectable in the subgranular zone of the dentate gyrus in the ZLC rats. However, only a few DCX-immunoreactive neurons were observed in the ZDF rats, and the DCX-immunoreactive neurons in the ZDF rats did not show fully developed processes. These results suggest that DCX-immunoreactive neurons were significantly decreased in an age-dependent manner and that DCX-immunoreactive neurons were also reduced in diabetic rats. In addition, the reduction in DCX-immunoreactive neurons in age matched rats may be associated with type II diabetes.
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Affiliation(s)
- In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and BK21 Program for Veterinary Science, Seoul National University, Seoul 151-742, South Korea
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