1
|
Sinks MR, Morrison DE, Ramdev RA, Lentzou S, Spritzer MD. Cell proliferation and cell death levels in the dentate gyrus correlate with home range size among adult male meadow voles. Neuroscience 2023:S0306-4522(23)00231-2. [PMID: 37245693 DOI: 10.1016/j.neuroscience.2023.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 05/07/2023] [Accepted: 05/20/2023] [Indexed: 05/30/2023]
Abstract
Neurogenesis occurs throughout adulthood within the dentate gyrus, and evidence indicates that these new neurons play a critical role in both spatial and social memory. However, a vast majority of past research on adult neurogenesis has involved experiments with captive mice and rats, making the generalizability of results to natural settings questionable. We assessed the connection between adult neurogenesis and memory by measuring the home range size of wild-caught, free-ranging meadow voles (Microtus pennsylvanicus). Adult male voles (n = 18) were captured, fitted with radio collars, and released back into their natural habitat, where each vole's home range was assessed using 40 radio-telemetry fixes over the course of 5 evenings. Voles were then recaptured, and brain tissue was collected. Cellular markers of cell proliferation (pHisH3, Ki67), neurogenesis (DCX), and pyknosis were labeled on histological sections and then quantified using either fluorescent or light microscopy. Voles with larger home ranges had significantly higher pHisH3+ cell densities within the granule cell layer and subgranular zone (GCL+SGZ) of the dentate gyrus and higher Ki67+ cell densities in the dorsal GCL+SGZ. Voles with larger ranges also had significantly higher pyknotic cell densities in the entire GCL+SGZ and in the dorsal GCL+SGZ. These results support the hypothesis that cell proliferation and cell death within the hippocampus are involved with spatial memory formation. However, a marker of neurogenesis (DCX+) was not correlated with range size, suggesting that there may be selective cellular turnover in the dentate gyrus when a vole is ranging through its environment.
Collapse
Affiliation(s)
- Mark R Sinks
- Department of Biology, Middlebury College, McCardell Bicentennial Hall, Middlebury, VT 05753, U.S.A.
| | - Daryl E Morrison
- Department of Biology, Middlebury College, McCardell Bicentennial Hall, Middlebury, VT 05753, U.S.A.
| | - Rajan A Ramdev
- Program in Neuroscience, Middlebury College, McCardell Bicentennial Hall, Middlebury, VT 05753, U.S.A.
| | - Stergiani Lentzou
- Program in Neuroscience, Middlebury College, McCardell Bicentennial Hall, Middlebury, VT 05753, U.S.A.
| | - Mark D Spritzer
- Department of Biology, Middlebury College, McCardell Bicentennial Hall, Middlebury, VT 05753, U.S.A; Program in Neuroscience, Middlebury College, McCardell Bicentennial Hall, Middlebury, VT 05753, U.S.A.
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Azeez IA, Awogbindin IO, Olayinka JN, Folarin RO, Adamu AS, Ior LD, Shehu AM, Mukhtar AI, Ajeigbe OF, Emokpae AO, Usende IL, Babatunde BR, Yusha'u Y, Olateju OI, Kamoga R, Benson AIO, Oparaji KC, Owemidu IO, Iliyasu MO, Imam MI, Olopade JO. Neural stem cell research in Africa: current realities and future prospects. Biol Open 2022; 11:280534. [PMID: 36326097 PMCID: PMC9641530 DOI: 10.1242/bio.059574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neural stem cells (NSCs) are immature progenitor cells that are found in developing and adult brains that have the potential of dividing actively and renewing themselves, with a complex form of gene expression. The generation of new brain cells in adult individuals was initially considered impossible, however, the landmark discovery of human neural stem cells in the hippocampus has been followed by further discoveries in other discreet regions of the brain. Investigation into the current state in Africa of the research and use of NSCs shows relatively limited activities on the continent. Information on the African application of NSCs for modelling disease mechanisms, drug discovery, and therapeutics is still limited. The International Brain Research Organization (IBRO)-African Regional Committee (ARC), with support from the Company of Biologists, and the Movement Disorder Society, sponsored the first African Basic School on NSC in Ibadan, Nigeria, with the vision of bringing together young neuroscientists and physicians across different fields in neuroscience to learn from leaders who have applied NSCs in stem cell research, the pathophysiology of neurodegenerative diseases, neuroanatomy, and neurotherapeutics. Twenty early-career researchers in academic institutions at junior and senior faculty cadres were selected from South Africa, Uganda and Nigeria. The students and organizer of the school, who wrote this review on the state of NSCs research in Africa, recommended the following: (1) other African countries can take a cue from South Africa and Nigeria in probing the phenomena of adult neurogenesis in unique animal species on the continent; (2) Africa should leverage the expertise and facilities of South African scientists and international collaborators in scaling up NSC research into these unique species and (3) Centers of Excellence should be established on the continent to serve as research hubs for training postgraduate students, and facilities for African scientists who trained overseas on NSCs.
Collapse
Affiliation(s)
- Idris A. Azeez
- Department of Veterinary Anatomy, University of Jos 1 , Jos, 930001 Nigeria
| | | | - Juliet N. Olayinka
- Department of Pharmacology and Therapeutics, Afe Babalola University 3 , Ado-Ekiti, 360001 Nigeria
| | - Royhaan O. Folarin
- Department of Anatomy, Olabisi Onabanjo University 4 , Ago-Iwoye, 120107 Nigeria
| | - Abubakar S. Adamu
- Department of Human Anatomy, Ahmadu Bello University 5 , Zaria, 810107 , Nigeria
| | - Lydia D. Ior
- Department of Pharmacology, University of Jos 6 , Jos, 930001 , Nigeria
| | - Asmau M. Shehu
- Department of Human Anatomy, Federal University Dutse 7 , Dutse, 720223 , Nigeria
- School of Anatomical Sciences, University of the Witwatersrand 8 , Johannesburg, Wits 2050 , South Africa
| | - Abubakar I. Mukhtar
- Department of Human Anatomy, Ahmadu Bello University 5 , Zaria, 810107 , Nigeria
| | - Olufunke F. Ajeigbe
- Elizade University, Ilara-Mokin, 340112 9 Department of Physical and Chemical Sciences, Biochemistry Programme , , Nigeria
| | | | - Ifukibot L. Usende
- Department of Veterinary Anatomy, University of Abuja 11 , Abuja, 900105 , Nigeria
| | | | - Yusuf Yusha'u
- Department of Human Physiology, Ahmadu Bello University 12 , Zaria, 810107 , Nigeria
| | - Oladiran I. Olateju
- School of Anatomical Sciences, University of the Witwatersrand 8 , Johannesburg, Wits 2050 , South Africa
| | - Ronald Kamoga
- Department of Pharmacology and Therapeutics, Mbarara University of Science and Technology 13 , Mbarara P.O. Box 1410 , Uganda
| | - Ayoola I. O. Benson
- Department of Human Anatomy, Elizade University, Ilara-Mokin 14 , Abakaliki, 482131 Nigeria
| | - Kenneth C. Oparaji
- Department of Physiology, Alex Ekwueme Federal University Ndufu-Alike 15 , Abakaliki, 482131 , Nigeria
| | - Idowu O. Owemidu
- Department of Physiology, Kogi State University 16 , Anyigba, 272102 , Nigeria
| | - Musa O. Iliyasu
- Department of Anatomy, Kogi State University 17 , Anyigba, 272102 , Nigeria
| | - Maryam I. Imam
- Department of Human Physiology, Ahmadu Bello University 12 , Zaria, 810107 , Nigeria
| | - James O. Olopade
- Department of Veterinary Anatomy, University of Ibadan 18 , Ibadan, 200005 , Nigeria
| |
Collapse
|
4
|
Faykoo-Martinez M, Collins T, Peragine D, Malik M, Javed F, Kolisnyk M, Ziolkowski J, Jeewa I, Cheng AH, Lowden C, Mascarenhas B, Cheng HYM, Holmes MM. Protracted neuronal maturation in a long-lived, highly social rodent. PLoS One 2022; 17:e0273098. [PMID: 36107951 PMCID: PMC9477366 DOI: 10.1371/journal.pone.0273098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 08/02/2022] [Indexed: 11/19/2022] Open
Abstract
Naked mole-rats are a long-lived rodent species (current lifespan >37 years) and an increasingly popular biomedical model. Naked mole-rats exhibit neuroplasticity across their long lifespan. Previous studies have begun to investigate their neurogenic patterns. Here, we test the hypothesis that neuronal maturation is extended in this long-lived rodent. We characterize cell proliferation and neuronal maturation in established rodent neurogenic regions over 12 months following seven days of consecutive BrdU injection. Given that naked mole-rats are eusocial (high reproductive skew where only a few socially-dominant individuals reproduce), we also looked at proliferation in brain regions relevant to the social-decision making network. Finally, we measured co-expression of EdU (newly-born cells), DCX (immature neuron marker), and NeuN (mature neuron marker) to assess the timeline of neuronal maturation in adult naked mole-rats. This work reaffirms the subventricular zone as the main source of adult cell proliferation and suggests conservation of the rostral migratory stream in this species. Our profiling of socially-relevant brain regions suggests that future work which manipulates environmental context can unveil how newly-born cells integrate into circuitry and facilitate adult neuroplasticity. We also find naked mole-rat neuronal maturation sits at the intersection of rodents and long-lived, non-rodent species: while neurons can mature by 3 weeks (rodent-like), most neurons mature at 5 months and hippocampal neurogenic levels are low (like long-lived species). These data establish a timeline for future investigations of longevity- and socially-related manipulations of naked mole-rat adult neurogenesis.
Collapse
Affiliation(s)
| | - Troy Collins
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Diana Peragine
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada
| | - Manahil Malik
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada
| | - Fiza Javed
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada
| | - Matthew Kolisnyk
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada
| | - Justine Ziolkowski
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada
| | - Imaan Jeewa
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada
| | - Arthur H. Cheng
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Christopher Lowden
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Brittany Mascarenhas
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Hai-Ying Mary Cheng
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
| | - Melissa M. Holmes
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
5
|
Bartkowska K, Tepper B, Turlejski K, Djavadian R. Postnatal and Adult Neurogenesis in Mammals, Including Marsupials. Cells 2022; 11:cells11172735. [PMID: 36078144 PMCID: PMC9455070 DOI: 10.3390/cells11172735] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 08/27/2022] [Accepted: 08/29/2022] [Indexed: 12/11/2022] Open
Abstract
In mammals, neurogenesis occurs during both embryonic and postnatal development. In eutherians, most brain structures develop embryonically; conversely, in marsupials, a number of brain structures develop after birth. The exception is the generation of granule cells in the dentate gyrus, olfactory bulb, and cerebellum of eutherian species. The formation of these structures starts during embryogenesis and continues postnatally. In both eutherians and marsupials, neurogenesis continues in the subventricular zone of the lateral ventricle (SVZ) and the dentate gyrus of the hippocampal formation throughout life. The majority of proliferated cells from the SVZ migrate to the olfactory bulb, whereas, in the dentate gyrus, cells reside within this structure after division and differentiation into neurons. A key aim of this review is to evaluate advances in understanding developmental neurogenesis that occurs postnatally in both marsupials and eutherians, with a particular emphasis on the generation of granule cells during the formation of the olfactory bulb, dentate gyrus, and cerebellum. We debate the significance of immature neurons in the piriform cortex of young mammals. We also synthesize the knowledge of adult neurogenesis in the olfactory bulb and the dentate gyrus of marsupials by considering whether adult-born neurons are essential for the functioning of a given area.
Collapse
Affiliation(s)
- Katarzyna Bartkowska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Beata Tepper
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Krzysztof Turlejski
- Faculty of Biology and Environmental Sciences, Cardinal Stefan Wyszynski University in Warsaw, 01-938 Warsaw, Poland
| | - Ruzanna Djavadian
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland
- Correspondence:
| |
Collapse
|
6
|
Yamamura Y, Kawamura Y, Oiwa Y, Oka K, Onishi N, Saya H, Miura K. Isolation and characterization of neural stem/progenitor cells in the subventricular zone of the naked mole-rat brain. Inflamm Regen 2021; 41:31. [PMID: 34719407 PMCID: PMC8559411 DOI: 10.1186/s41232-021-00182-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/18/2021] [Indexed: 12/11/2022] Open
Abstract
Background The naked mole-rat (NMR) is the longest-lived rodent with a maximum lifespan of more than 37 years and shows a negligible senescence phenotype, suggesting that tissue stem cells of NMRs are highly capable of maintaining homeostasis. However, the properties of NMR tissue stem cells, including neural stem cells (NSCs), are largely unclear. Methods Neural stem/progenitor cells (NS/PCs) were isolated from the subventricular zone of the neonate NMR brain (NMR-NS/PCs) and cultured in neurosphere and adherent culture conditions. Expression of NSC markers and markers of neurons, astrocytes, and oligodendrocytes was analyzed by immunocytochemistry. In adherent culture conditions, the proliferation rate and cell cycle of NMR-NS/PCs were assessed and compared with those of NS/PCs from mice (mouse-NS/PCs). The DNA damage response to γ-irradiation was analyzed by immunocytochemistry and reverse transcription-quantitative PCR. Results NMR-NS/PCs expressed several NSC markers and differentiated into neurons, astrocytes, and oligodendrocytes. NMR-NS/PCs proliferated markedly slower than mouse-NS/PCs, and a higher percentage of NMR-NS/PCs than mouse-NS/PCs was in G0/G1 phase. Notably, upon γ-irradiation, NMR-NS/PCs exhibited a faster initiation of the DNA damage response and were less prone to dying than mouse-NS/PCs. Conclusions NMR-NS/PCs were successfully isolated and cultured. The slow proliferation of NMR-NS/PCs and their resistance to DNA damage may help to prevent stem cell exhaustion in the brain during the long lifespan of NMRs. Our findings provide novel insights into the mechanism underlying delayed aging of NMRs. Further analysis of NMR tissue stem cells may lead to the development of new strategies that can prevent aging in humans. Supplementary Information The online version contains supplementary material available at 10.1186/s41232-021-00182-7.
Collapse
Affiliation(s)
- Yuki Yamamura
- Department of Aging and Longevity Research, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-0811, Japan
| | - Yoshimi Kawamura
- Department of Aging and Longevity Research, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-0811, Japan
| | - Yuki Oiwa
- Department of Aging and Longevity Research, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-0811, Japan
| | - Kaori Oka
- Department of Aging and Longevity Research, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-0811, Japan
| | - Nobuyuki Onishi
- Division of Gene Regulation, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, 160-0016, Japan
| | - Hideyuki Saya
- Division of Gene Regulation, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, 160-0016, Japan
| | - Kyoko Miura
- Department of Aging and Longevity Research, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-0811, Japan. .,Center for Metabolic Regulation of Healthy Aging, Kumamoto University, Kumamoto, 860-8556, Japan.
| |
Collapse
|
7
|
Adult Neural Plasticity in Naked Mole-Rats: Implications of Fossoriality, Longevity and Sociality on the Brain's Capacity for Change. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1319:105-135. [PMID: 34424514 DOI: 10.1007/978-3-030-65943-1_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Naked mole-rats (Heterocephalus glaber) are small African rodents that have many unique behavioral and physiological adaptations well-suited for testing hypotheses about mammalian neural plasticity. In this chapter, we focus on three features of naked mole-rat biology and how they impact neural plasticity in this species: (1) their fossorial lifestyle, (2) their extreme longevity with a lack of demonstrable senescence, and (3) their unusual social structure. Critically, each of these features requires some degree of biological flexibility. First, their fossorial habitat situates them in an environment with characteristics to which the central nervous system is particularly sensitive (e.g., oxygen content, photoperiod, spatial complexity). Second, their long lifespan requires adaptations to combat senescence and declines in neural functioning. Finally, their extreme reproductive skew and sustained ability for release from reproductive suppression indicates remarkable neural sensitivity to the sociosexual environment that is distinct from chronological age. These three features of naked mole-rat life are not mutually exclusive, but they do each offer unique considerations for the possibilities, constraints, and mechanisms associated with adult neural plasticity.
Collapse
|
8
|
Oosthuizen MK. Exploratory behaviour, memory and neurogenesis in the social Damaraland mole-rat ( Fukomys damarensis). J Exp Biol 2020; 223:jeb221093. [PMID: 32532860 DOI: 10.1242/jeb.221093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 06/03/2020] [Indexed: 12/15/2022]
Abstract
Both exploratory behaviour and spatial memory are important for survival in dispersing animals. Exploratory behaviour is triggered by novel environments and having a better spatial memory of the surroundings provides an adaptive advantage to the animals. Spatial challenges can also affect neurogenesis in the hippocampus by increasing cell proliferation and enhancing survival of young neurons. In social Damaraland mole-rat colonies, the social hierarchy is largely based on body size. Individuals with different social statuses in these colonies display different dispersal behaviours and as behavioural differences have been linked to dispersal behaviour, I investigated exploratory behaviour, memory and hippocampal neurogenesis in wild-captured Damaraland mole-rats. Dispersal behaviour gives rise to differential exploratory behaviour in Damaraland mole-rats; they readily explored in a novel environment but resident, worker mole-rats explored more slowly. In the Y-maze, animals entered the escape hole significantly faster by the second day; however, they did not make fewer wrong turns with successive days of the experiment. Female dispersers did not show any improvement in time to reach the escape hole or the number of wrong turns over the 4 day experimental period. Damaraland male and female dispersers employ different dispersal strategies, and this is evident in their approach to the learning task. Females are less motivated to complete the task, leading to a difference in behaviour, and this has important survival implications for the different sexes. Finally, in the context of memory, adult neurogenesis does not seem to be a good marker in mole-rats as it is generally low and has not been investigated thoroughly enough to determine which and how other factors can influence it in these animals.
Collapse
Affiliation(s)
- Maria K Oosthuizen
- Department of Zoology & Entomology, University of Pretoria, Private Bag X20, Pretoria 0028, South Africa
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
| |
Collapse
|
9
|
Popov NA, Skulachev VP. Neotenic Traits in Heterocephalus glaber and Homo sapiens. BIOCHEMISTRY (MOSCOW) 2019; 84:1484-1489. [DOI: 10.1134/s0006297919120071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
|
10
|
González-Maciel A, Romero-Velázquez RM, Alfaro-Rodríguez A, Sanchez Aparicio P, Reynoso-Robles R. Prenatal exposure to oxcarbazepine increases hippocampal apoptosis in rat offspring. J Chem Neuroanat 2019; 103:101729. [PMID: 31794794 DOI: 10.1016/j.jchemneu.2019.101729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 11/29/2019] [Accepted: 11/29/2019] [Indexed: 01/18/2023]
Abstract
This study assessed apoptosis in the offspring of rats exposed to oxcarbazepine (OXC) from day 7 to 15 of gestation. Three groups of pregnant Wistar rats were used: 1) Control, treated with saline solution; 2) treated with 100 mg/kg OXC; 3) treated with 100 mg/kg of carbamazepine (CBZ, as a positive control for apoptosis); the route of administration was intragastric. Apoptosis was detected at three postnatal ages using the TUNEL technique in the CA1, and CA3 regions of the hippocampus and in the dentate gyrus (DG); neurogenesis was assessed in the DG using an antibody against doublecortin. The litter characteristics were recorded. OXC increased apoptosis in all regions (p < 0.01) at the three ages evaluated. Lamination disruption occurred in CA1 and CA3 due to the neuron absence and to ectopic neurons; there were also malformations in the dorsal lamina of the DG in 38% and 25% of the pups born from rats treated with OXC and CBZ respectively. CBZ also increased apoptosis. No clear effect on neurogenesis in the DG was observed. The size of the litter was smaller (p < 0.01) in the experimental groups. Nineteen-day OXC fetuses had low weight (p < 0.01), but 21 and 30 postnatal days old CBZ and OXC pups were overweight (p < 0.01). The results demonstrate that OXC administered during gestation is pro-apoptotic, alters the cytoarchitecture of the hippocampus, reduces litter size, and probably influences postnatal weight. We provide evidence of the proapoptotic effect of CBZ when administered early in gestation.
Collapse
Affiliation(s)
- A González-Maciel
- Laboratory of Cell and Tissue Morphology, Instituto Nacional de Pediatría, Secretaría de Salud, Insurgentes Sur No. 3700-C, Mexico City, C. P. 04530, Mexico.
| | - R M Romero-Velázquez
- Laboratory of Cell and Tissue Morphology, Instituto Nacional de Pediatría, Secretaría de Salud, Insurgentes Sur No. 3700-C, Mexico City, C. P. 04530, Mexico.
| | - A Alfaro-Rodríguez
- Division of Neurosciences, Instituto Nacional de Rehabilitación, "Luis Guillermo Ibarra Ibarra", Secretaría de Salud, Col. Arenal de Guadalupe, Mexico City, C.P. 14389, Mexico.
| | - P Sanchez Aparicio
- Faculty of Veterinary Medicine, Department of Pharmacology, Universidad Autónoma del Estado de México, Mexico
| | - R Reynoso-Robles
- Laboratory of Cell and Tissue Morphology, Instituto Nacional de Pediatría, Secretaría de Salud, Insurgentes Sur No. 3700-C, Mexico City, C. P. 04530, Mexico.
| |
Collapse
|
11
|
Dollas A, Oelschläger HHA, Begall S, Burda H, Malkemper EP. Brain atlas of the African mole-rat Fukomys anselli. J Comp Neurol 2019; 527:1885-1900. [PMID: 30697737 PMCID: PMC6593805 DOI: 10.1002/cne.24647] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 12/21/2018] [Accepted: 12/26/2018] [Indexed: 11/06/2022]
Abstract
African mole-rats are subterranean rodents that spend their whole life in underground burrow systems. They show a range of morphological and physiological adaptations to their ecotope, for instance severely reduced eyes and specialized somatosensory, olfactory, and auditory systems. These adaptations are also reflected in the accessory sensory pathways in the brain that process the input coming from the sensory organs. So far, a brain atlas was available only for the naked mole-rat (Heterocephalus glaber). The Ansell's mole-rat (Fukomys anselli) has been the subject of many investigations in various disciplines (ethology, sensory physiology, and anatomy) including magnetic orientation. It is therefore surprising that an atlas of the brain of this species was not available so far. Here, we present a comprehensive atlas of the Ansell's mole-rat brain based on Nissl and Klüver-Barrera stained sections. We identify and label 375 brain regions and discuss selected differences from the brain of the closely related naked mole-rat as well as from epigeic mammals (rat), with a particular focus on the auditory brainstem. This atlas can serve as a reference for future neuroanatomical investigations of subterranean mammals.
Collapse
Affiliation(s)
- Alexa Dollas
- Department of General Zoology, Faculty of BiologyUniversity of Duisburg‐EssenEssenGermany
| | - Helmut H. A. Oelschläger
- Department of Anatomy III (Dr. Senckenbergische Anatomie), Medical FacultyJohann Wolfgang Goethe UniversityFrankfurtGermany
| | - Sabine Begall
- Department of General Zoology, Faculty of BiologyUniversity of Duisburg‐EssenEssenGermany
- Department of Game Management and Wildlife BiologyFaculty of Forestry and Wood Sciences, Czech University of Life SciencesPraha 6Czech Republic
| | - Hynek Burda
- Department of General Zoology, Faculty of BiologyUniversity of Duisburg‐EssenEssenGermany
- Department of Game Management and Wildlife BiologyFaculty of Forestry and Wood Sciences, Czech University of Life SciencesPraha 6Czech Republic
| | - Erich Pascal Malkemper
- Department of General Zoology, Faculty of BiologyUniversity of Duisburg‐EssenEssenGermany
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC), Campus‐Vienna‐Biocenter 1Vienna 1030Austria
| |
Collapse
|
12
|
Oppenheim RW. Adult Hippocampal Neurogenesis in Mammals (and Humans): The Death of a Central Dogma in Neuroscience and its Replacement by a New Dogma. Dev Neurobiol 2019; 79:268-280. [DOI: 10.1002/dneu.22674] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 03/12/2019] [Accepted: 03/12/2019] [Indexed: 01/31/2023]
Affiliation(s)
- Ronald W. Oppenheim
- Department of Neurobiology and Anatomy, The Neuroscience Program Wake Forest School of Medicine Medical Center Blvd. Winston‐Salem NC 27157‐1010
| |
Collapse
|
13
|
Cameron S, Lopez A, Glabman R, Abrams E, Johnson S, Field C, Gulland FMD, Buckmaster PS. Proportional loss of parvalbumin-immunoreactive synaptic boutons and granule cells from the hippocampus of sea lions with temporal lobe epilepsy. J Comp Neurol 2019; 527:2341-2355. [PMID: 30861128 DOI: 10.1002/cne.24680] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/18/2019] [Accepted: 03/02/2019] [Indexed: 01/10/2023]
Abstract
One in 26 people develop epilepsy and in these temporal lobe epilepsy (TLE) is common. Many patients display a pattern of neuron loss called hippocampal sclerosis. Seizures usually start in the hippocampus but underlying mechanisms remain unclear. One possibility is insufficient inhibition of dentate granule cells. Normally parvalbumin-immunoreactive (PV) interneurons strongly inhibit granule cells. Humans with TLE display loss of PV interneurons in the dentate gyrus but questions persist. To address this, we evaluated PV interneuron and bouton numbers in California sea lions (Zalophus californianus) that naturally develop TLE after exposure to domoic acid, a neurotoxin that enters the marine food chain during harmful algal blooms. Sclerotic hippocampi were identified by the loss of Nissl-stained hilar neurons. Stereological methods were used to estimate the number of granule cells and PV interneurons per dentate gyrus. Sclerotic hippocampi contained fewer granule cells, fewer PV interneurons, and fewer PV synaptic boutons, and the ratio of granule cells to PV interneurons was higher than in controls. To test whether fewer boutons was attributable to loss versus reduced immunoreactivity, expression of synaptotagmin-2 (syt2) was evaluated. Syt2 is also expressed in boutons of PV interneurons. Sclerotic hippocampi displayed proportional losses of syt2-immunoreactive boutons, PV boutons, and granule cells. There was no significant difference in the average numbers of PV- or syt2-positive boutons per granule cell between control and sclerotic hippocampi. These findings do not address functionality of surviving synapses but suggest reduced granule cell inhibition in TLE is not attributable to anatomical loss of PV boutons.
Collapse
Affiliation(s)
- Starr Cameron
- Department of Comparative Medicine, Stanford University, Stanford, California
| | - Ariana Lopez
- Department of Comparative Medicine, Stanford University, Stanford, California.,College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina
| | - Raisa Glabman
- Department of Comparative Medicine, Stanford University, Stanford, California.,School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Emily Abrams
- Department of Comparative Medicine, Stanford University, Stanford, California
| | | | - Cara Field
- The Marine Mammal Center, Sausalito, California
| | | | - Paul S Buckmaster
- Department of Comparative Medicine, Stanford University, Stanford, California.,Department of Neurology & Neurological Sciences, Stanford University, Stanford, California
| |
Collapse
|
14
|
Watson C, Binks D. Elongation of the CA1 field of the septal hippocampus in ungulates. J Comp Neurol 2019; 527:818-832. [PMID: 30393922 DOI: 10.1002/cne.24573] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 10/24/2018] [Accepted: 10/24/2018] [Indexed: 11/06/2022]
Abstract
It is widely assumed that the hippocampal formation seen in laboratory rodents and in primates is typical of that seen in other mammals. We have tested this assumption by examining sections of brains of 56 mammals from 20 mammalian orders from images on the brainmuseum.org website. We found wide variation in the form of the hippocampal formation, the most extreme examples of which are seen in ungulates, which possess an unusual elongation of the distal CA1 of the septal hippocampus. This phenomenon has not previously been reported. In individual coronal sections of the brains of seven artiodactyl ungulates, the pyramidal layer of CA1 is four times as long as CA2 + CA3. In a perissodactyl ungulate (Burchell's zebra) the distal end of CA1 is so large that it forms a number of folds. A similar but less pronounced CA1 elongation was seen in the brains of 14 carnivores. A modest elongation of CA1 is also present in some other placental mammals, notably the elephant shrew, hyrax, capybara, beaver, and rabbit. The elongation was not present in brains of primates, marsupials, or monotremes. The distal part of CA1 has been shown to play a role in object integration into the spatial map. We hypothesize that the distal CA1 enlargement could serve to enhance the ability to integrate objects into spatial navigation, which would be an advantage for migrating herds of ungulates. We suggest that the remarkable elongation of Q5 CA1 represents a major evolutionary specialization in the ungulates.
Collapse
Affiliation(s)
- Charles Watson
- School of Biological Sciences, The University of Western Australia, Perth, Australia.,Neuroscience Research Australia, Sydney, Australia
| | - Daniel Binks
- School of Biological Sciences, The University of Western Australia, Perth, Australia.,Perron Institute of Neurological and Translational Science
| |
Collapse
|
15
|
Sociality does not drive the evolution of large brains in eusocial African mole-rats. Sci Rep 2018; 8:9203. [PMID: 29907782 PMCID: PMC6003933 DOI: 10.1038/s41598-018-26062-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 05/02/2018] [Indexed: 11/15/2022] Open
Abstract
The social brain hypothesis (SBH) posits that the demands imposed on individuals by living in cohesive social groups exert a selection pressure favouring the evolution of large brains and complex cognitive abilities. Using volumetry and the isotropic fractionator to determine the size of and numbers of neurons in specific brain regions, here we test this hypothesis in African mole-rats (Bathyergidae). These subterranean rodents exhibit a broad spectrum of social complexity, ranging from strictly solitary through to eusocial cooperative breeders, but feature similar ecologies and life history traits. We found no positive association between sociality and neuroanatomical correlates of information-processing capacity. Solitary species are larger, tend to have greater absolute brain size and have more neurons in the forebrain than social species. The neocortex ratio and neuronal counts correlate negatively with social group size. These results are clearly inconsistent with the SBH and show that the challenges coupled with sociality in this group of rodents do not require brain enlargement or fundamental reorganization. These findings suggest that group living or pair bonding per se does not select strongly for brain enlargement unless coupled with Machiavellian interactions affecting individual fitness.
Collapse
|
16
|
Oosthuizen MK. From Mice to Mole-Rats: Species-Specific Modulation of Adult Hippocampal Neurogenesis. Front Neurosci 2017; 11:602. [PMID: 29163007 PMCID: PMC5670158 DOI: 10.3389/fnins.2017.00602] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 10/16/2017] [Indexed: 11/23/2022] Open
Abstract
Rodent populations living in their natural environments have very diverse ecological and life history profiles that may differ substantially from that of conventional laboratory rodents. Free-living rodents show species-specific neurogenesis that are dependent on their unique biology and ecology. This perspective aims to illustrate the benefit of studying wild rodent species in conjunction with laboratory rodents. African mole-rats are discussed in terms of habitat complexity, social structures, and longevity. African mole-rats are a group of subterranean rodents, endemic to Africa, that show major differences in both intrinsic and extrinsic traits compared to the classical rodent models. Mole-rats exhibit a spectrum of sociality within a single family, ranging from solitary to eusocial. This continuum of sociality provides a platform for comparative testing of hypotheses. Indeed, species differences are apparent both in learning ability and hippocampal neurogenesis. In addition, social mole-rat species display a reproductive division of labor that also results in differential hippocampal neurogenesis, independent of age, offering further scope for comparison. In conclusion, it is evident that neurogenesis studies on conventional laboratory rodents are not necessarily representative, specifically because of a lack of diversity in life histories, uniform habitats, and low genetic variability. The observed level of adult neurogenesis in the dentate gyrus is the result of an intricate balance between many contributing factors, which appear to be specific to distinct groups of animals. The ultimate understanding of the functional and adaptive role of adult neurogenesis will involve research on both laboratory animals and natural rodent populations.
Collapse
Affiliation(s)
- Maria K Oosthuizen
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| |
Collapse
|
17
|
Skulachev VP, Holtze S, Vyssokikh MY, Bakeeva LE, Skulachev MV, Markov AV, Hildebrandt TB, Sadovnichii VA. Neoteny, Prolongation of Youth: From Naked Mole Rats to “Naked Apes” (Humans). Physiol Rev 2017; 97:699-720. [DOI: 10.1152/physrev.00040.2015] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
It has been suggested that highly social mammals, such as naked mole rats and humans, are long-lived due to neoteny (the prolongation of youth). In both species, aging cannot operate as a mechanism facilitating natural selection because the pressure of this selection is strongly reduced due to 1) a specific social structure where only the “queen” and her “husband(s)” are involved in reproduction (naked mole rats) or 2) substituting fast technological progress for slow biological evolution (humans). Lists of numerous traits of youth that do not disappear with age in naked mole rats and humans are presented and discussed. A high resistance of naked mole rats to cancer, diabetes, cardiovascular and brain diseases, and many infections explains why their mortality rate is very low and almost age-independent and why their lifespan is more than 30 years, versus 3 years in mice. In young humans, curves of mortality versus age start at extremely low values. However, in the elderly, human mortality strongly increases. High mortality rates in other primates are observed at much younger ages than in humans. The inhibition of the aging process in humans by specific drugs seems to be a promising approach to prolong our healthspan. This might be a way to retard aging, which is already partially accomplished via the natural physiological phenomenon neoteny.
Collapse
Affiliation(s)
- Vladimir P. Skulachev
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, Russia; Lomonosov Moscow State University, Institute of Mitoengineering, Moscow, Russia; Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany; Lomonosov Moscow State University, Biological Faculty, Moscow, Russia; Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow, Russia
| | - Susanne Holtze
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, Russia; Lomonosov Moscow State University, Institute of Mitoengineering, Moscow, Russia; Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany; Lomonosov Moscow State University, Biological Faculty, Moscow, Russia; Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow, Russia
| | - Mikhail Y. Vyssokikh
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, Russia; Lomonosov Moscow State University, Institute of Mitoengineering, Moscow, Russia; Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany; Lomonosov Moscow State University, Biological Faculty, Moscow, Russia; Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow, Russia
| | - Lora E. Bakeeva
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, Russia; Lomonosov Moscow State University, Institute of Mitoengineering, Moscow, Russia; Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany; Lomonosov Moscow State University, Biological Faculty, Moscow, Russia; Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow, Russia
| | - Maxim V. Skulachev
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, Russia; Lomonosov Moscow State University, Institute of Mitoengineering, Moscow, Russia; Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany; Lomonosov Moscow State University, Biological Faculty, Moscow, Russia; Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow, Russia
| | - Alexander V. Markov
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, Russia; Lomonosov Moscow State University, Institute of Mitoengineering, Moscow, Russia; Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany; Lomonosov Moscow State University, Biological Faculty, Moscow, Russia; Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow, Russia
| | - Thomas B. Hildebrandt
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, Russia; Lomonosov Moscow State University, Institute of Mitoengineering, Moscow, Russia; Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany; Lomonosov Moscow State University, Biological Faculty, Moscow, Russia; Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow, Russia
| | - Viktor A. Sadovnichii
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, Russia; Lomonosov Moscow State University, Institute of Mitoengineering, Moscow, Russia; Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany; Lomonosov Moscow State University, Biological Faculty, Moscow, Russia; Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow, Russia
| |
Collapse
|
18
|
Orr ME, Garbarino VR, Salinas A, Buffenstein R. Extended Postnatal Brain Development in the Longest-Lived Rodent: Prolonged Maintenance of Neotenous Traits in the Naked Mole-Rat Brain. Front Neurosci 2016; 10:504. [PMID: 27877105 PMCID: PMC5099538 DOI: 10.3389/fnins.2016.00504] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 10/21/2016] [Indexed: 11/24/2022] Open
Abstract
The naked mole-rat (NMR) is the longest-lived rodent with a maximum lifespan >31 years. Intriguingly, fully-grown naked mole-rats (NMRs) exhibit many traits typical of neonatal rodents. However, little is known about NMR growth and maturation, and we question whether sustained neotenous features when compared to mice, reflect an extended developmental period, commensurate with their exceptionally long life. We tracked development from birth to 3 years of age in the slowest maturing organ, the brain, by measuring mass, neural stem cell proliferation, axonal, and dendritic maturation, synaptogenesis and myelination. NMR brain maturation was compared to data from similar sized rodents, mice, and to that of long-lived mammals, humans, and non-human primates. We found that at birth, NMR brains are significantly more developed than mice, and rather are more similar to those of newborn primates, with clearly laminated hippocampi and myelinated white matter tracts. Despite this more mature brain at birth than mice, postnatal NMR brain maturation occurs at a far slower rate than mice, taking four-times longer than required for mice to fully complete brain development. At 4 months of age, NMR brains reach 90% of adult size with stable neuronal cytostructural protein expression whereas myelin protein expression does not plateau until 9 months of age in NMRs, and synaptic protein expression continues to change throughout the first 3 years of life. Intriguingly, NMR axonal composition is more similar to humans than mice whereby NMRs maintain expression of three-repeat (3R) tau even after brain growth is complete; mice experience an abrupt downregulation of 3R tau by postnatal day 8 which continues to diminish through 6 weeks of age. We have identified key ages in NMR cerebral development and suggest that the long-lived NMR may provide neurobiologists an exceptional model to study brain developmental processes that are compressed in common short-lived laboratory animal models.
Collapse
Affiliation(s)
- Miranda E Orr
- Department of Physiology, University of Texas Health Science Center at San AntonioSan Antonio, TX, USA; The Barshop Institute for Longevity, Aging Studies, University of Texas Health Science Center at San AntonioSan Antonio, TX, USA
| | - Valentina R Garbarino
- Department of Physiology, University of Texas Health Science Center at San Antonio San Antonio, TX, USA
| | - Angelica Salinas
- Department of Physiology, University of Texas Health Science Center at San Antonio San Antonio, TX, USA
| | - Rochelle Buffenstein
- Department of Physiology, University of Texas Health Science Center at San AntonioSan Antonio, TX, USA; The Barshop Institute for Longevity, Aging Studies, University of Texas Health Science Center at San AntonioSan Antonio, TX, USA; Calico Life Sciences LLCSouth San Francisco, CA, USA
| |
Collapse
|
19
|
LaDage LD. Factors That Modulate Neurogenesis: A Top-Down Approach. BRAIN, BEHAVIOR AND EVOLUTION 2016; 87:184-190. [PMID: 27560485 DOI: 10.1159/000446906] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although hippocampal neurogenesis in the adult brain has been conserved across the vertebrate lineage, laboratory studies have primarily examined this phenomenon in rodent models. This approach has been successful in elucidating important factors and mechanisms that can modulate rates of hippocampal neurogenesis, including hormones, environmental complexity, learning and memory, motor stimulation, and stress. However, recent studies have found that neurobiological research on neurogenesis in rodents may not easily translate to, or explain, neurogenesis patterns in nonrodent systems, particularly in species examined in the field. This review examines some of the evolutionary and ecological variables that may also modulate neurogenesis patterns. This 'top-down' and more naturalistic approach, which incorporates ecology and natural history, particularly of nonmodel species, may allow for a more comprehensive understanding of the functional significance of neurogenesis.
Collapse
Affiliation(s)
- Lara D LaDage
- Division of Mathematics and Natural Sciences, Penn State University Altoona, Altoona, Pa., USA
| |
Collapse
|
20
|
Trading new neurons for status: Adult hippocampal neurogenesis in eusocial Damaraland mole-rats. Neuroscience 2016; 324:227-37. [DOI: 10.1016/j.neuroscience.2016.03.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 02/19/2016] [Accepted: 03/07/2016] [Indexed: 11/21/2022]
|
21
|
Sobrero R, Fernández-Aburto P, Ly-Prieto Á, Delgado SE, Mpodozis J, Ebensperger LA. Effects of Habitat and Social Complexity on Brain Size, Brain Asymmetry and Dentate Gyrus Morphology in Two Octodontid Rodents. BRAIN, BEHAVIOR AND EVOLUTION 2016; 87:51-64. [DOI: 10.1159/000444741] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 02/17/2016] [Indexed: 11/19/2022]
Abstract
Navigational and social challenges due to habitat conditions and sociality are known to influence dentate gyrus (DG) morphology, yet the relative importance of these factors remains unclear. Thus, we studied three natural populations of O. lunatus (Los Molles) and Octodon degus (El Salitre and Rinconada), two caviomorph species that differ in the extent of sociality and with contrasting vegetation cover of habitat used. The brains and DG of male and female breeding degus with simultaneous information on their physical and social environments were examined. The extent of sociality was quantified from total group size and range area overlap. O. degus at El Salitre was more social than at Rinconada and than O. lunatus from Los Molles. The use of transects to quantify cover of vegetation (and other physical objects in the habitat) and measures of the spatial behavior of animals indicated animal navigation based on unique cues or global landmarks is more cognitively challenging to O. lunatus. During lactation, female O. lunatus had larger brains than males. Relative DG volume was similar across sexes and populations. The right hemisphere of male and female O. lunatus had more cells than the left hemisphere, with DG directional asymmetry not found in O. degus. Degu population differences in brain size and DG cell number seemed more responsive to differences in habitat than to differences in sociality. Yet, large-sized O. degus (but not O. lunatus) that ranged over larger areas and were members of larger social groups had more DG cells per hemisphere. Thus, within-population variation in DG cell number by hemisphere was consistent with a joint influence of habitat and sociality in O. degus at El Salitre.
Collapse
|
22
|
van Dijk RM, Huang SH, Slomianka L, Amrein I. Taxonomic Separation of Hippocampal Networks: Principal Cell Populations and Adult Neurogenesis. Front Neuroanat 2016; 10:22. [PMID: 27013984 PMCID: PMC4783399 DOI: 10.3389/fnana.2016.00022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 02/23/2016] [Indexed: 11/13/2022] Open
Abstract
While many differences in hippocampal anatomy have been described between species, it is typically not clear if they are specific to a particular species and related to functional requirements or if they are shared by species of larger taxonomic units. Without such information, it is difficult to infer how anatomical differences may impact on hippocampal function, because multiple taxonomic levels need to be considered to associate behavioral and anatomical changes. To provide information on anatomical changes within and across taxonomic ranks, we present a quantitative assessment of hippocampal principal cell populations in 20 species or strain groups, with emphasis on rodents, the taxonomic group that provides most animals used in laboratory research. Of special interest is the importance of adult hippocampal neurogenesis (AHN) in species-specific adaptations relative to other cell populations. Correspondence analysis of cell numbers shows that across taxonomic units, phylogenetically related species cluster together, sharing similar proportions of principal cell populations. CA3 and hilus are strong separators that place rodent species into a tight cluster based on their relatively large CA3 and small hilus while non-rodent species (including humans and non-human primates) are placed on the opposite side of the spectrum. Hilus and CA3 are also separators within rodents, with a very large CA3 and rather small hilar cell populations separating mole-rats from other rodents that, in turn, are separated from each other by smaller changes in the proportions of CA1 and granule cells. When adult neurogenesis is included, the relatively small populations of young neurons, proliferating cells and hilar neurons become main drivers of taxonomic separation within rodents. The observations provide challenges to the computational modeling of hippocampal function, suggest differences in the organization of hippocampal information streams in rodent and non-rodent species, and support emerging concepts of functional and structural interactions between CA3 and the dentate gyrus.
Collapse
Affiliation(s)
- R Maarten van Dijk
- Functional Neuroanatomy, Institute of Anatomy, University of ZürichZurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH ZurichZürich, Switzerland; Department of Health Sciences and Technology, Institute of Human Movement Sciences and Sport, ETH ZurichZürich, Switzerland
| | - Shih-Hui Huang
- Functional Neuroanatomy, Institute of Anatomy, University of ZürichZurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH ZurichZürich, Switzerland; Department of Health Sciences and Technology, Institute of Human Movement Sciences and Sport, ETH ZurichZürich, Switzerland
| | - Lutz Slomianka
- Functional Neuroanatomy, Institute of Anatomy, University of Zürich Zurich, Switzerland
| | - Irmgard Amrein
- Functional Neuroanatomy, Institute of Anatomy, University of ZürichZurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH ZurichZürich, Switzerland
| |
Collapse
|
23
|
Amrein I, Nosswitz M, Slomianka L, van Dijk RM, Engler S, Klaus F, Raineteau O, Azim K. Septo-temporal distribution and lineage progression of hippocampal neurogenesis in a primate (Callithrix jacchus) in comparison to mice. Front Neuroanat 2015; 9:85. [PMID: 26175670 PMCID: PMC4484228 DOI: 10.3389/fnana.2015.00085] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 06/11/2015] [Indexed: 12/17/2022] Open
Abstract
Adult born neurons in the hippocampus show species-specific differences in their numbers, the pace of their maturation and their spatial distribution. Here, we present quantitative data on adult hippocampal neurogenesis in a New World primate, the common marmoset (Callithrix jacchus) that demonstrate parts of the lineage progression and age-related changes. Proliferation was largely (∼70%) restricted to stem cells or early progenitor cells, whilst the remainder of the cycling pool could be assigned almost exclusively to Tbr2+ intermediate precursor cells in both neonate and adult animals (20–122 months). Proliferating DCX+ neuroblasts were virtually absent in adults, although rare MCM2+/DCX+ co-expression revealed a small, persisting proliferative potential. Co-expression of DCX with calretinin was very limited in marmosets, suggesting that these markers label distinct maturational stages. In adult marmosets, numbers of MCM2+, Ki67+, and significantly Tbr2+, DCX+, and CR+ cells declined with age. The distributions of granule cells, proliferating cells and DCX+ young neurons along the hippocampal longitudinal axis were equal in marmosets and mice. In both species, a gradient along the hippocampal septo-temporal axis was apparent for DCX+ and resident granule cells. Both cell numbers are higher septally than temporally, whilst proliferating cells were evenly distributed along this axis. Relative to resident granule cells, however, the ratio of proliferating cells and DCX+ neurons remained constant in the septal, middle, and temporal hippocampus. In marmosets, the extended phase of the maturation of young neurons that characterizes primate hippocampal neurogenesis was due to the extension in a large CR+/DCX- cell population. This clear dissociation between DCX+ and CR+ young neurons has not been reported for other species and may therefore represent a key primate-specific feature of adult hippocampal neurogenesis.
Collapse
Affiliation(s)
- Irmgard Amrein
- Functional Neuroanatomy, Institute of Anatomy, University of Zürich Zürich, Switzerland ; Neuroscience Center Zurich, University of Zürich and ETH Zürich Zürich, Switzerland
| | - Michael Nosswitz
- Functional Neuroanatomy, Institute of Anatomy, University of Zürich Zürich, Switzerland
| | - Lutz Slomianka
- Functional Neuroanatomy, Institute of Anatomy, University of Zürich Zürich, Switzerland
| | - R Maarten van Dijk
- Functional Neuroanatomy, Institute of Anatomy, University of Zürich Zürich, Switzerland ; Institute of Human Movement Sciences and Sport, Department of Health Sciences and Technology, ETH Zürich Zürich, Switzerland
| | - Stefanie Engler
- Functional Neuroanatomy, Institute of Anatomy, University of Zürich Zürich, Switzerland
| | - Fabienne Klaus
- Functional Neuroanatomy, Institute of Anatomy, University of Zürich Zürich, Switzerland
| | - Olivier Raineteau
- Inserm U846, Stem Cell and Brain Research Institute, Bron France ; Université de Lyon, Bron France
| | - Kasum Azim
- Neuroscience Center Zurich, University of Zürich and ETH Zürich Zürich, Switzerland
| |
Collapse
|
24
|
Protracted brain development in a rodent model of extreme longevity. Sci Rep 2015; 5:11592. [PMID: 26118676 PMCID: PMC4484490 DOI: 10.1038/srep11592] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 05/27/2015] [Indexed: 12/11/2022] Open
Abstract
Extreme longevity requires the continuous and large-scale adaptation of organ systems to delay senescence. Naked mole rats are the longest-living rodents, whose nervous system likely undergoes life-long adaptive reorganization. Nevertheless, neither the cellular organization of their cerebral cortex nor indices of structural neuronal plasticity along extreme time-scales have been established. We find that adult neurogenesis and neuronal migration are not unusual in naked mole rat brains. Instead, we show the prolonged expression of structural plasticity markers, many recognized as being developmentally controlled, and multi-year-long postnatal neuromorphogenesis and spatial synapse refinement in hippocampal and olfactory structures of the naked mole rat brain. Neurophysiological studies on identified hippocampal neurons demonstrated that morphological differentiation is disconnected from the control of excitability in all neuronal contingents regardless of their ability to self-renew. Overall, we conclude that naked mole rats show an extremely protracted period of brain maturation that may permit plasticity and resilience to neurodegenerative processes over their decades-long life span. This conclusion is consistent with the hypothesis that naked mole rats are neotenous, with retention of juvenile characteristics to permit survival in a hypoxic environment, with extreme longevity a consequence of greatly retarded development.
Collapse
|
25
|
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.
Collapse
Affiliation(s)
- Irmgard Amrein
- Institute of Anatomy, University of Zürich-Irchel, CH-8057 Zürich, Switzerland
| |
Collapse
|
26
|
Huang S, Slomianka L, Farmer AJ, Kharlamova AV, Gulevich RG, Herbeck YE, Trut LN, Wolfer DP, Amrein I. Selection for tameness, a key behavioral trait of domestication, increases adult hippocampal neurogenesis in foxes. Hippocampus 2015; 25:963-75. [DOI: 10.1002/hipo.22420] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2015] [Indexed: 01/31/2023]
Affiliation(s)
- Shihhui Huang
- Department of Health Sciences and Technology; Institute of Human Movement Sciences and Sport; ETH Zurich Zürich Switzerland
- Division of Functional Neuroanatomy; Institute of Anatomy, Functional Neuroanatomy, University of Zurich; Zürich Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich; Zürich Switzerland
| | - Lutz Slomianka
- Division of Functional Neuroanatomy; Institute of Anatomy, Functional Neuroanatomy, University of Zurich; Zürich Switzerland
| | | | - Anastasiya V. Kharlamova
- Division of Siberian; Institute of Cytology and Genetics of the Russian Academy of Sciences; Novosibirsk Russia
| | - Rimma G. Gulevich
- Division of Siberian; Institute of Cytology and Genetics of the Russian Academy of Sciences; Novosibirsk Russia
| | - Yury E. Herbeck
- Division of Siberian; Institute of Cytology and Genetics of the Russian Academy of Sciences; Novosibirsk Russia
| | - Lyudmila N. Trut
- Division of Siberian; Institute of Cytology and Genetics of the Russian Academy of Sciences; Novosibirsk Russia
| | - David P. Wolfer
- Department of Health Sciences and Technology; Institute of Human Movement Sciences and Sport; ETH Zurich Zürich Switzerland
- Division of Functional Neuroanatomy; Institute of Anatomy, Functional Neuroanatomy, University of Zurich; Zürich Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich; Zürich Switzerland
- Zurich Center for Integrative Human Physiology ZIHP; University of Zurich; Zurich Switzerland
| | - Irmgard Amrein
- Division of Functional Neuroanatomy; Institute of Anatomy, Functional Neuroanatomy, University of Zurich; Zürich Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich; Zürich Switzerland
| |
Collapse
|