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Nagarajan R, Lyu J, Kambali M, Wang M, Courtney CD, Christian-Hinman CA, Rudolph U. Genetic Ablation of Dentate Hilar Somatostatin-Positive GABAergic Interneurons is Sufficient to Induce Cognitive Impairment. Mol Neurobiol 2024; 61:567-580. [PMID: 37642935 PMCID: PMC11285310 DOI: 10.1007/s12035-023-03586-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/15/2023] [Indexed: 08/31/2023]
Abstract
Aging is often associated with a decline in cognitive function. A reduction in the number of somatostatin-positive (SOM+) interneurons in the dentate gyrus (DG) has been described in cognitively impaired but not in unimpaired aged rodents. However, it remains unclear whether the reduction in SOM + interneurons in the DG hilus is causal for age-related cognitive dysfunction. We hypothesized that hilar SOM+ interneurons play an essential role in maintaining cognitive function and that a reduction in the number of hilar SOM + interneurons might be sufficient to induce cognitive dysfunction. Hilar SOM+ interneurons were ablated by expressing a diphtheria toxin transgene specifically in these interneurons, which resulted in a reduction in the number of SOM+ /GAD-67+ neurons and dendritic spine density in the DG. C-fos and Iba-1 immunostainings were increased in DG and CA3, but not CA1, and BDNF protein expression in the hippocampus was decreased. Behavioral testing showed a reduced recognition index in the novel object recognition test, decreased alternations in the Y maze test, and longer latencies and path lengths in the learning and reversal learning phases of the Morris water maze. Our results show that partial genetic ablation of SOM+ hilar interneurons is sufficient to increase activity in DG and CA3, as has been described to occur with aging and to induce an impairment of learning and memory functions. Thus, partial ablation of hilar SOM + interneurons may be a significant contributing factor to age-related cognitive dysfunction. These mice may also be useful as a cellularly defined model of hippocampal aging.
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Affiliation(s)
- Rajasekar Nagarajan
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jinrui Lyu
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Maltesh Kambali
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Muxiao Wang
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Connor D Courtney
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Catherine A Christian-Hinman
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Uwe Rudolph
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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Grigoryan G, Harada H, Knobloch-Bollmann HS, Kilias A, Kaufhold D, Kulik A, Eyre MD, Bartos M. Synaptic plasticity at the dentate gyrus granule cell to somatostatin-expressing interneuron synapses supports object location memory. Proc Natl Acad Sci U S A 2023; 120:e2312752120. [PMID: 38091292 PMCID: PMC10742375 DOI: 10.1073/pnas.2312752120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 10/14/2023] [Indexed: 12/18/2023] Open
Abstract
Somatostatin-expressing interneurons (SOMIs) in the mouse dentate gyrus (DG) receive feedforward excitation from granule cell (GC) mossy fiber (MF) synapses and provide feedback lateral inhibition onto GC dendrites to support environment representation in the DG network. Although this microcircuitry has been implicated in memory formation, little is known about activity-dependent plastic changes at MF-SOMI synapses and their influence on behavior. Here, we report that the metabotropic glutamate receptor 1α (mGluR1α) is required for the induction of associative long-term potentiation (LTP) at MF-SOMI synapses. Pharmacological block of mGluR1α, but not mGluR5, prevented synaptic weight changes. LTP at MF-SOMI synapses was postsynaptically induced, required increased intracellular Ca2+, involved G-protein-mediated and Ca2+-dependent (extracellular signal-regulated kinase) ERK1/2 pathways, and the activation of NMDA receptors. Specific knockdown of mGluR1α in DG-SOMIs by small hairpin RNA expression prevented MF-SOMI LTP, reduced SOMI recruitment, and impaired object location memory. Thus, postsynaptic mGluR1α-mediated MF-plasticity at SOMI input synapses critically supports DG-dependent mnemonic functions.
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Affiliation(s)
- Gayane Grigoryan
- Laboratory of Systems & Cellular Neuroscience, Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - Harumi Harada
- Molecular Physiology, Institute for Physiology II, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - H. Sophie Knobloch-Bollmann
- Laboratory of Systems & Cellular Neuroscience, Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - Antje Kilias
- Laboratory of Systems & Cellular Neuroscience, Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - Dorthe Kaufhold
- Laboratory of Systems & Cellular Neuroscience, Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - Akos Kulik
- Molecular Physiology, Institute for Physiology II, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - Mark D. Eyre
- Laboratory of Systems & Cellular Neuroscience, Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - Marlene Bartos
- Laboratory of Systems & Cellular Neuroscience, Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
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3
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McDermott KD, Frechou MA, Jordan JT, Martin SS, Gonçalves JT. Delayed formation of neural representations of space in aged mice. Aging Cell 2023; 22:e13924. [PMID: 37491802 PMCID: PMC10497831 DOI: 10.1111/acel.13924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 05/31/2023] [Accepted: 06/20/2023] [Indexed: 07/27/2023] Open
Abstract
Aging is associated with cognitive deficits, with spatial memory being very susceptible to decline. The hippocampal dentate gyrus (DG) is important for processing spatial information in the brain and is particularly vulnerable to aging, yet its sparse activity has led to difficulties in assessing changes in this area. Using in vivo two-photon calcium imaging, we compared DG neuronal activity and representations of space in young and aged mice walking on an unfamiliar treadmill. We found that calcium activity was significantly higher and less tuned to location in aged mice, resulting in decreased spatial information encoded in the DG. However, with repeated exposure to the same treadmill, both spatial tuning and information levels in aged mice became similar to young mice, while activity remained elevated. Our results show that spatial representations of novel environments are impaired in the aged hippocampus and gradually improve with increased familiarity. Moreover, while the aged DG is hyperexcitable, this does not disrupt neural representations of familiar environments.
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Affiliation(s)
- Kelsey D. McDermott
- Dominick P. Purpura Department of Neuroscience and Gottesmann Institute for Stem Cell Biology and Regenerative MedicineAlbert Einstein College of MedicineBronxNew YorkUSA
| | - M. Agustina Frechou
- Dominick P. Purpura Department of Neuroscience and Gottesmann Institute for Stem Cell Biology and Regenerative MedicineAlbert Einstein College of MedicineBronxNew YorkUSA
| | - Jake T. Jordan
- Dominick P. Purpura Department of Neuroscience and Gottesmann Institute for Stem Cell Biology and Regenerative MedicineAlbert Einstein College of MedicineBronxNew YorkUSA
| | - Sunaina S. Martin
- Dominick P. Purpura Department of Neuroscience and Gottesmann Institute for Stem Cell Biology and Regenerative MedicineAlbert Einstein College of MedicineBronxNew YorkUSA
| | - J. Tiago Gonçalves
- Dominick P. Purpura Department of Neuroscience and Gottesmann Institute for Stem Cell Biology and Regenerative MedicineAlbert Einstein College of MedicineBronxNew YorkUSA
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Lyu J, Nagarajan R, Kambali M, Wang M, Rudolph U. Selective inhibition of somatostatin-positive dentate hilar interneurons induces age-related cellular changes and cognitive dysfunction. PNAS NEXUS 2023; 2:pgad134. [PMID: 37168673 PMCID: PMC10165806 DOI: 10.1093/pnasnexus/pgad134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/19/2023] [Accepted: 04/04/2023] [Indexed: 05/13/2023]
Abstract
The cellular basis of age-related impairments of hippocampal function is not fully understood. In order to evaluate the role of somatostatin-positive (Sst+) interneurons in the dentate gyrus (DG) hilus in this process, we chemogenetically inhibited Sst+ interneurons in the DG hilus. Chronic chemogenetic inhibition (CCI) of these neurons resulted in increased c-Fos staining in the DG hilus, a decrease in the percentage of GAD67- and of Sst-expressing interneurons in the DG, and increased microglial activation in DG, CA3, and CA1. Total dendritic length and spine density were reduced in DG and CA1, suggesting reduced dendritic complexity. Behaviorally, the recognition index in an object recognition task and the percentage of spontaneous alternations in the Y-maze were decreased, while in both initial and reversal learning in the Morris water maze, the latencies to find the hidden platform were increased, suggesting cognitive dysfunction. Our findings establish a causal role for a reduced function of Sst+ interneurons in the DG hilus for cognitive decline and suggest that this reduced function may contribute to age-related impairments of learning and memory. Furthermore, our CCI mice may represent a cellularly defined model of hippocampal aging.
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Affiliation(s)
- Jinrui Lyu
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802-6178, USA
- Neuroscience Program, College of Liberal Arts and Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61802-6178, USA
| | - Rajasekar Nagarajan
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802-6178, USA
| | - Maltesh Kambali
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802-6178, USA
| | - Muxiao Wang
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802-6178, USA
- Neuroscience Program, College of Liberal Arts and Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61802-6178, USA
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Gramuntell Y, Klimczak P, Coviello S, Perez-Rando M, Nacher J. Effects of Aging on the Structure and Expression of NMDA Receptors of Somatostatin Expressing Neurons in the Mouse Hippocampus. Front Aging Neurosci 2022; 13:782737. [PMID: 35002680 PMCID: PMC8733323 DOI: 10.3389/fnagi.2021.782737] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/23/2021] [Indexed: 11/13/2022] Open
Abstract
Changes in the physiology, neurochemistry and structure of neurons, particularly of their dendritic spines, are thought to be crucial players in age-related cognitive decline. One of the most studied brain structures affected by aging is the hippocampus, known to be involved in different essential cognitive processes. While the aging-associated quantitative changes in dendritic spines of hippocampal pyramidal cells have already been studied, the relationship between aging and the structural dynamics of hippocampal interneurons remains relatively unknown. Spines are not a frequent feature in cortical inhibitory neurons, but these postsynaptic structures are abundant in a subpopulation of somatostatin expressing interneurons, particularly in oriens-lacunosum moleculare (O-LM) cells in the hippocampal CA1. Previous studies from our laboratory have shown that the spines of these interneurons are highly plastic and influenced by NMDA receptor manipulation. Thus, in the present study, we have investigated the impact of aging on this interneuronal subpopulation. The analyses were performed in 3−, 9−, and 16-month-old GIN mice, a strain in which somatostatin positive interneurons express GFP. We studied the changes in the density of dendritic spines, en passant boutons, and the expression of NMDA receptors (GluN1 and GluN2B) using confocal microscopy and image analysis. We observed a significant decrease in dendritic spine density in 9-month-old animals when compared with 3-month-old animals. We also observed a decrease in the expression of the GluN2B subunit in O-LM cells, but not of that of GluN1, during aging. These results will constitute the basis for more advanced studies of the structure and connectivity of interneurons during aging and their contribution to cognitive decline.
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Affiliation(s)
- Yaiza Gramuntell
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain
| | - Patrycja Klimczak
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain.,Spanish National Network for Research in Mental Health, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | - Simona Coviello
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain
| | - Marta Perez-Rando
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain.,Spanish National Network for Research in Mental Health, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain.,Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
| | - Juan Nacher
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain.,Spanish National Network for Research in Mental Health, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain.,Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
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Kotah JM, Hoeijmakers L, Nutma E, Lucassen PJ, Korosi A. Early-life stress does not alter spatial memory performance, hippocampal neurogenesis, neuroinflammation, or telomere length in 20-month-old male mice. Neurobiol Stress 2021; 15:100379. [PMID: 34430678 PMCID: PMC8369064 DOI: 10.1016/j.ynstr.2021.100379] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 08/05/2021] [Accepted: 08/06/2021] [Indexed: 01/03/2023] Open
Abstract
Early-life stress (ES) increases the risk for psychopathology and cognitive decline later in life. Because the neurobiological substrates affected by ES (i.e., cognition, neuroplasticity, and neuroinflammation) are also altered in aging, we set out to investigate if and how ES in the first week of life affects these domains at an advanced age, and how ES modulates the aging trajectory per se. We subjected C57BL/6j mice to an established ES mouse model from postnatal days 2–9. Mice underwent behavioral testing at 19 months of age and were sacrificed at 20 months to investigate their physiology, hippocampal neuroplasticity, neuroinflammation, and telomere length. ES mice, as a group, did not perform differently from controls in the open field or Morris water maze (MWM). Hippocampal neurogenesis and synaptic marker gene expression were not different in ES mice at this age. While we find aging-associated alterations to neuroinflammatory gene expression and telomere length, these were unaffected by ES. When integrating the current data with those from our previously reported 4- and 10-month-old cohorts, we conclude that ES leads to a ‘premature’ shift in the aging trajectory, consisting of early changes that do not further worsen at the advanced age of 20 months. This could be explained e.g. by a ‘floor’ effect in ES-induced impairments, and/or age-induced impairments in control mice. Future studies should help understand how exactly ES affects the overall aging trajectory. Early-life stress (ES) exposure does not worsen water maze learning in aged male mice. ES does not affect brain plasticity markers at 20 months of age. Hippocampal telomere length is reduced by aging but unaffected by ES. ES leads to a premature aging trajectory that does not worsen with aging.
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Affiliation(s)
- Janssen M Kotah
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, Amsterdam, the Netherlands
| | - Lianne Hoeijmakers
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, Amsterdam, the Netherlands
| | - Erik Nutma
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, Amsterdam, the Netherlands
| | - Paul J Lucassen
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, Amsterdam, the Netherlands
| | - Aniko Korosi
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, Amsterdam, the Netherlands
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Kim B, Im HI. Chronic nicotine impairs sparse motor learning via striatal fast-spiking parvalbumin interneurons. Addict Biol 2021; 26:e12956. [PMID: 32767546 PMCID: PMC8243919 DOI: 10.1111/adb.12956] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 07/09/2020] [Accepted: 07/21/2020] [Indexed: 01/06/2023]
Abstract
Nicotine can diversely affect neural activity and motor learning in animals. However, the impact of chronic nicotine on striatal activity in vivo and motor learning at long-term sparse timescale remains unknown. Here, we demonstrate that chronic nicotine persistently suppresses the activity of striatal fast-spiking parvalbumin interneurons, which mediate nicotine-induced deficit in sparse motor learning. Six weeks of longitudinal in vivo single-unit recording revealed that mice show reduced activity of fast-spiking interneurons in the dorsal striatum during chronic nicotine exposure and withdrawal. The reduced firing of fast-spiking interneurons was accompanied by spike broadening, diminished striatal delta oscillation power, and reduced sample entropy in local field potential. In addition, chronic nicotine withdrawal impaired motor learning with a weekly sparse training regimen but did not affect general locomotion and anxiety-like behavior. Lastly, the excitatory DREADD hM3Dq-mediated activation of striatal fast-spiking parvalbumin interneurons reversed the chronic nicotine withdrawal-induced deficit in sparse motor learning. Taken together, we identified that chronic nicotine withdrawal impairs sparse motor learning via disruption of activity in striatal fast-spiking parvalbumin interneurons. These findings suggest that sparse motor learning paradigm can reveal the subtle effect of nicotine withdrawal on motor function and that striatal fast-spiking parvalbumin interneurons are a neural substrate of nicotine's effect on motor learning.
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Affiliation(s)
- Baeksun Kim
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia (DTC), Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology (UST), Seoul, Republic of Korea
| | - Heh-In Im
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia (DTC), Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology (UST), Seoul, Republic of Korea
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
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8
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Bi D, Wen L, Wu Z, Shen Y. GABAergic dysfunction in excitatory and inhibitory (E/I) imbalance drives the pathogenesis of Alzheimer's disease. Alzheimers Dement 2020; 16:1312-1329. [PMID: 32543726 DOI: 10.1002/alz.12088] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 01/28/2020] [Accepted: 02/10/2020] [Indexed: 12/28/2022]
Abstract
OBJECTIVE To propose a new hypothesis that GABAergic dysfunction in excitatory and inhibitory (E/I) imbalance drives the pathogenesis of Alzheimer's disease (AD). BACKGROUND Synaptic dysfunction and E/I imbalance emerge decades before the appearance of cognitive decline in AD patients, which contribute to neurodegeneration. Initially, E/I imbalance was thought to occur first, due to dysfunction of the glutamatergic and cholinergic systems. However, new evidence has demonstrated that the GABAergic system, the counterpart of E/I balance and the major inhibitory neurotransmitter system in the central nervous system, is altered enormously and that this contributes to E/I imbalance and further AD pathogenesis. NEW HYPOTHESIS Alterations to the GABAergic system, induced by multiple AD pathogenic or risk factors, contribute to E/I imbalance and AD pathogenesis. MAJOR CHALLENGES FOR THE HYPOTHESIS This GABAergic hypothesis accounts for many critical questions and common challenges confronting a new hypothesis of AD pathogenesis. More specifically, it explains why amyloid beta (Aβ), β-secretase (BACE1), apolipoprotein E4 gene (APOE ε4), hyperactive glia cells, contributes to AD pathogenesis and why age and sex are the risk factors of AD. GABAergic dysfunction promotes the spread of Aβ pathology throughout the AD brain and associated cognitive impairments, and the induction of dysfunction induced by these varied risk factors shares this common neurobiology leading to E/I imbalance. In turn, some of these factors exacerbate GABAergic dysfunction and E/I imbalance. Moreover, the GABAergic system modulates various brain functions and thus, the GABAergic hypothesis accounts for nonamnestic manifestations. Furthermore, corrections of E/I balance through manipulation of GABAergic functions have shown positive outcomes in preclinical and clinical studies, suggesting the potential of the GABAergic system as a therapeutic target in AD. LINKAGE TO OTHER MAJOR THEORIES Dysfunction of the GABAergic system is induced by multiple critical signaling pathways, which include the existing major theories of AD pathogenesis, such as the Aβ and neuroinflammation hypotheses. In a new perspective, this GABAergic hypothesis accounts for the E/I imbalance and related excitotoxicity, which contribute to cognitive decline and AD pathogenesis. Therefore, the GABAergic system could be a key target to restore, at least partially, the E/I balance and cognitive function in AD patients.
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Affiliation(s)
- Danlei Bi
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Institute on Aging and Brain Disorders, University of Sciences and Technology of China, Hefei, China.,Neurodegenerative Disease Research Center, University of Science and Technology of China, Hefei, China.,Hefei National Laboratory for Physical Sciences at the Microscale, Neurodegenerative Disorder Research Center, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Lang Wen
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Institute on Aging and Brain Disorders, University of Sciences and Technology of China, Hefei, China.,Neurodegenerative Disease Research Center, University of Science and Technology of China, Hefei, China.,Hefei National Laboratory for Physical Sciences at the Microscale, Neurodegenerative Disorder Research Center, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Zujun Wu
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Institute on Aging and Brain Disorders, University of Sciences and Technology of China, Hefei, China.,Neurodegenerative Disease Research Center, University of Science and Technology of China, Hefei, China.,Hefei National Laboratory for Physical Sciences at the Microscale, Neurodegenerative Disorder Research Center, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yong Shen
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Institute on Aging and Brain Disorders, University of Sciences and Technology of China, Hefei, China.,Neurodegenerative Disease Research Center, University of Science and Technology of China, Hefei, China.,Hefei National Laboratory for Physical Sciences at the Microscale, Neurodegenerative Disorder Research Center, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
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9
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Chen Y, Gao X, Liu Q, Zeng L, Zhang K, Mu K, Zhang D, Zou H, Wu N, Ou J, Wang Q, Mao S. Alpha-asarone improves cognitive function of aged rats by alleviating neuronal excitotoxicity via GABAA receptors. Neuropharmacology 2020; 162:107843. [DOI: 10.1016/j.neuropharm.2019.107843] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 11/03/2019] [Accepted: 11/04/2019] [Indexed: 12/20/2022]
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10
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Reduced cognitive performance in aged rats correlates with increased excitation/inhibition ratio in the dentate gyrus in response to lateral entorhinal input. Neurobiol Aging 2019; 82:120-127. [DOI: 10.1016/j.neurobiolaging.2019.07.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 07/16/2019] [Accepted: 07/16/2019] [Indexed: 11/18/2022]
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Hernandez AR, Hernandez CM, Truckenbrod LM, Campos KT, McQuail JA, Bizon JL, Burke SN. Age and Ketogenic Diet Have Dissociable Effects on Synapse-Related Gene Expression Between Hippocampal Subregions. Front Aging Neurosci 2019; 11:239. [PMID: 31607897 PMCID: PMC6755342 DOI: 10.3389/fnagi.2019.00239] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 08/19/2019] [Indexed: 01/01/2023] Open
Abstract
As the number of individuals living beyond the age of 65 is rapidly increasing, so is the need to develop strategies to combat the age-related cognitive decline that may threaten independent living. Although the link between altered neuronal signaling and age-related cognitive impairments is not completely understood, it is evident that declining cognitive abilities are at least partially due to synaptic dysfunction. Aging is accompanied by well-documented changes in both excitatory and inhibitory synaptic signaling across species. Age-related synaptic alterations are not uniform across the brain, however, with different regions showing unique patterns of vulnerability in advanced age. In the hippocampus, increased activity within the CA3 subregion has been observed across species, and this can be reversed with anti-epileptic medication. In contrast to CA3, the dentate gyrus shows reduced activity with age and declining metabolic activity. Ketogenic diets have been shown to decrease seizure incidence and severity in epilepsy, improve metabolic function in diabetes type II, and improve cognitive function in aged rats. This link between neuronal activity and metabolism suggests that metabolic interventions may be able to ameliorate synaptic signaling deficits accompanying advanced age. We therefore investigated the ability of a dietary regimen capable of inducing nutritional ketosis and improving cognition to alter synapse-related gene expression across the dentate gyrus, CA3 and CA1 subregions of the hippocampus. Following 12 weeks of a ketogenic or calorie-matched standard diet, RTq-PCR was used to quantify expression levels of excitatory and inhibitory synaptic signaling genes within CA1, CA3 and dentate gyrus. While there were no age or diet-related changes in CA1 gene expression, expression levels were significantly altered within CA3 by age and within the dentate gyrus by diet for several genes involved in presynaptic glutamate regulation and postsynaptic excitation and plasticity. These data demonstrate subregion-specific alterations in synaptic signaling with age and the potential for a ketogenic diet to alter these processes in dissociable ways across different brain structures that are uniquely vulnerable in older animals.
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Affiliation(s)
- Abbi R. Hernandez
- Department of Neurosciences, University of Florida, Gainesville, FL, United States
| | - Caesar M. Hernandez
- Department of Neurosciences, University of Florida, Gainesville, FL, United States
| | - Leah M. Truckenbrod
- Department of Neurosciences, University of Florida, Gainesville, FL, United States
| | - Keila T. Campos
- Department of Neurosciences, University of Florida, Gainesville, FL, United States
| | - Joseph A. McQuail
- Department of Physiology, Pharmacology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Jennifer L. Bizon
- Department of Neurosciences, University of Florida, Gainesville, FL, United States
| | - Sara N. Burke
- Department of Neurosciences, University of Florida, Gainesville, FL, United States
- Institute on Aging, University of Florida, Gainesville, FL, United States
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12
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GABA A Receptors Are Well Preserved in the Hippocampus of Aged Mice. eNeuro 2019; 6:ENEURO.0496-18.2019. [PMID: 31340951 PMCID: PMC6709233 DOI: 10.1523/eneuro.0496-18.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 07/02/2019] [Accepted: 07/15/2019] [Indexed: 01/04/2023] Open
Abstract
GABA is the primary inhibitory neurotransmitter in the nervous system. GABAA receptors (GABAARs) are pentameric ionotropic channels. Subunit composition of the receptors is associated with the affinity of GABA binding and its downstream inhibitory actions. Fluctuations in subunit expression levels with increasing age have been demonstrated in animal and human studies. However, our knowledge regarding the age-related hippocampal GABAAR expression changes is limited and based on rat studies. This study is the first analysis of the aging-related changes of the GABAAR subunit expression in the CA1, CA2/3, and dentate gyrus regions of the mouse hippocampus. Using Western blotting and immunohistochemistry we found that the GABAergic system is robust, with no significant age-related differences in GABAAR α1, α2, α3, α5, β3, and γ2 subunit expression level differences found between the young (6 months) and old (21 months) age groups in any of the hippocampal regions examined. However, we detected a localized decrease of α2 subunit expression around the soma, proximal dendrites, and in the axon initial segment of pyramidal cells in the CA1 and CA3 regions that is accompanied by a pronounced upregulation of the α2 subunit immunoreactivity in the neuropil of aged mice. In summary, GABAARs are well preserved in the mouse hippocampus during normal aging although GABAARs in the hippocampus are severely affected in age-related neurological disorders, including Alzheimer’s disease.
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Aguado-Llera D, Canelles S, Fernández-Mendívil C, Frago LM, Argente J, Arilla-Ferreiro E, López MG, Barrios V. Improvement in inflammation is associated with the protective effect of Gly-Pro-Glu and cycloprolylglycine against Aβ-induced depletion of the hippocampal somatostatinergic system. Neuropharmacology 2019; 151:112-126. [PMID: 30981749 DOI: 10.1016/j.neuropharm.2019.04.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 04/02/2019] [Accepted: 04/06/2019] [Indexed: 02/08/2023]
Abstract
Glycine-proline-glutamate (GPE) is a cleaved tripeptide of IGF-I that can be processed to cycloprolylglycine (cPG) in the brain. IGF-I protects the hippocampal somatostatinergic system from β-amyloid (Aβ) insult and although neither IGF-I-derived peptides bind to IGF-I receptors, they exert protective actions in several neurological disorders. As their effects on the hippocampal somatostatinergic system remain unknown, the objective of this study was to evaluate if cPG and/or GPE prevent the deleterious effects of Aβ25-35 infusion on this system and whether changes in intracellular-related signaling and interleukin (IL) content are involved in their protective effect. We also determined the effect of cPG or GPE co-administration with Aβ25-35 on IL secretion in glial cultures and the influence of these ILs on signaling activation and somatostatin synthesis in neuronal cultures. cPG or GPE co-administration reduced Aβ-induced cell death and pro-inflammatory ILs, increased IL-4 and partially avoided the reduction of components of the somatostatinergic system affected by Aβ25-35. GPE increased activation of Akt and CREB and reduced GSK3β activation and astrogliosis, whereas cPG increased phosphorylation of extracellular signal-regulated kinases. Both peptides converged in the activation of mTOR and S6 kinase. Co-administration of these peptides with Aβ25-35 to glial cultures increased IL-4 and reduced IL-1β; this release of IL-4 could be responsible for activation of Akt and increased somatostatin in neuronal cultures. Our findings suggest that cPG and GPE exert protective effects against Aβ on the somatostatinergic system by a reduction of the inflammatory environment that may activate different pro-survival pathways in these neurons.
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Affiliation(s)
- David Aguado-Llera
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación Sanitaria La Princesa, Madrid, Spain
| | - Sandra Canelles
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación Sanitaria La Princesa, Madrid, Spain; CIBER Fisiopatología Obesidad y Nutrición (CB06/03), Instituto de Salud Carlos III, Madrid, Spain
| | - Cristina Fernández-Mendívil
- Department of Pharmacology and Therapeutics and Institute Teófilo Hernando for Drug Discovery, Universidad Autónoma de Madrid, Madrid, Spain
| | - Laura M Frago
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación Sanitaria La Princesa, Madrid, Spain; CIBER Fisiopatología Obesidad y Nutrición (CB06/03), Instituto de Salud Carlos III, Madrid, Spain; Department of Pediatrics, Universidad Autónoma de Madrid, Madrid, Spain
| | - Jesús Argente
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación Sanitaria La Princesa, Madrid, Spain; CIBER Fisiopatología Obesidad y Nutrición (CB06/03), Instituto de Salud Carlos III, Madrid, Spain; Department of Pediatrics, Universidad Autónoma de Madrid, Madrid, Spain; IMDEA Food Institute, CEI UAM + CSIC, Madrid, Spain
| | | | - Manuela G López
- Department of Pharmacology and Therapeutics and Institute Teófilo Hernando for Drug Discovery, Universidad Autónoma de Madrid, Madrid, Spain
| | - Vicente Barrios
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación Sanitaria La Princesa, Madrid, Spain; CIBER Fisiopatología Obesidad y Nutrición (CB06/03), Instituto de Salud Carlos III, Madrid, Spain.
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14
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Johnson SA, Turner SM, Lubke KN, Cooper TL, Fertal KE, Bizon JL, Maurer AP, Burke SN. Experience-Dependent Effects of Muscimol-Induced Hippocampal Excitation on Mnemonic Discrimination. Front Syst Neurosci 2019; 12:72. [PMID: 30687032 PMCID: PMC6335355 DOI: 10.3389/fnsys.2018.00072] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 12/21/2018] [Indexed: 12/12/2022] Open
Abstract
Memory requires similar episodes with overlapping features to be represented distinctly, a process that is disrupted in many clinical conditions as well as normal aging. Data from humans have linked this ability to activity in hippocampal CA3 and dentate gyrus (DG). While animal models have shown the perirhinal cortex is critical for disambiguating similar stimuli, hippocampal activity has not been causally linked to discrimination abilities. The goal of the current study was to determine how disrupting CA3/DG activity would impact performance on a rodent mnemonic discrimination task. Rats were surgically implanted with bilateral guide cannulae targeting dorsal CA3/DG. In Experiment 1, the effect of intra-hippocampal muscimol on target-lure discrimination was assessed within subjects in randomized blocks. Muscimol initially impaired discrimination across all levels of target-lure similarity, but performance improved on subsequent test blocks irrespective of stimulus similarity and infusion condition. To clarify these results, Experiment 2 examined whether prior experience with objects influenced the effect of muscimol on target-lure discrimination. Rats that received vehicle infusions in a first test block, followed by muscimol in a second block, did not show discrimination impairments for target-lure pairs of any similarity. In contrast, rats that received muscimol infusions in the first test block were impaired across all levels of target-lure similarity. Following discrimination tests, rats from Experiment 2 were trained on a spatial alternation task. Muscimol infusions increased the number of spatial errors made, relative to vehicle infusions, confirming that muscimol remained effective in disrupting behavioral performance. At the conclusion of behavioral experiments, fluorescence in situ hybridization for the immediate-early genes Arc and Homer1a was used to determine the proportion of neurons active following muscimol infusion. Contrary to expectations, muscimol increased neural activity in DG. An additional experiment was carried out to quantify neural activity in naïve rats that received an intra-hippocampal infusion of vehicle or muscimol. Results confirmed that muscimol led to DG excitation, likely through its actions on interneuron populations in hilar and molecular layers of DG and consequent disinhibition of principal cells. Taken together, our results suggest disruption of coordinated neural activity across the hippocampus impairs mnemonic discrimination when lure stimuli are novel.
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Affiliation(s)
- Sarah A Johnson
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Sean M Turner
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, United States
| | - Katelyn N Lubke
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Tara L Cooper
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Kaeli E Fertal
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Jennifer L Bizon
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Andrew P Maurer
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States.,Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Sara N Burke
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States.,Institute on Aging, University of Florida, Gainesville, FL, United States
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15
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Branch A, Monasterio A, Blair G, Knierim JJ, Gallagher M, Haberman RP. Aged rats with preserved memory dynamically recruit hippocampal inhibition in a local/global cue mismatch environment. Neurobiol Aging 2019; 76:151-161. [PMID: 30716540 DOI: 10.1016/j.neurobiolaging.2018.12.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 12/14/2018] [Accepted: 12/27/2018] [Indexed: 10/27/2022]
Abstract
Similar to elderly humans, aged outbred Long-Evans rats exhibit individual differences in memory abilities, including a subset of aged rats that maintain memory function on par with young adults. Such individuals provide a basis for investigating mechanisms of resilience to age-related decline. The present study examined hippocampal gene expression in young adults and aged rats with preserved memory function under behavioral task conditions well established for assessing information processing central to the formation of episodic memory. Although behavioral measures and hippocampal gene induction associated with neural activity and synaptic plasticity were similar across age groups, a marker for inhibitory interneuron function in the hippocampal formation was distinctively increased only in aged rats but not in young adults. Because heightened hippocampal neural activity is associated with age-related memory impairment across species, including rats, monkeys, and humans, this finding may represent an adaptive homeostatic adjustment necessary to maintain neural plasticity and memory function in aging.
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Affiliation(s)
- Audrey Branch
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Amy Monasterio
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Grace Blair
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - James J Knierim
- Department of Neuroscience and Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Michela Gallagher
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Rebecca P Haberman
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA.
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16
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Prévôt TD, Viollet C, Epelbaum J, Dominguez G, Béracochéa D, Guillou JL. sst 2-receptor gene deletion exacerbates chronic stress-induced deficits: Consequences for emotional and cognitive ageing. Prog Neuropsychopharmacol Biol Psychiatry 2018; 86:390-400. [PMID: 29409919 DOI: 10.1016/j.pnpbp.2018.01.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 01/17/2018] [Accepted: 01/30/2018] [Indexed: 02/07/2023]
Abstract
This study investigated whether sst2 gene deletion interacts with age and chronic stress exposure to produce exacerbated emotional and cognitive ageing. Middle-aged (10-12 month) sst2 knockout (sst2KO) and wild-type (WT) mice underwent an unpredictable chronic mild stress (UCMS) procedure for 6 weeks or no stress for control groups. This was followed by a battery of tests to assess emotional and cognitive functions and neuroendocrine status (CORT level). A re-evaluation was performed 6 months later (i.e. with 18-month-old mice). UCMS reproduced neuroendocrine and behavioral features of stress-related disorders such as elevated circulating CORT levels, physical deteriorations, increased anxiety- and depressive-like behaviors and working memory impairments. sst2KO mice displayed behavioral alterations which were similar to stressed WT and exhibited exacerbated changes following UCMS exposure. The evaluations performed in the older mice showed significant long-term effects of UCMS exposure. Old sst2KO mice previously exposed to UCMS exhibited spatial learning and memory accuracy impairments and high levels of anxiety-like behaviors which drastically added to the effects of normal ageing. Spatial abilities and emotionality scores (mean z-scores) measured both at the UCMS outcome and 6 months later were correlated with the initially measured CORT levels in middle-age. The present findings indicate that the deletion of the sst2 receptor gene produces chronic hypercorticosteronemia and exacerbates sensitivity to stressors which over time, have consequences on ageing brain function processes.
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Affiliation(s)
- Thomas Damien Prévôt
- Université de Bordeaux, Pessac, France; Centre National de la Recherche Scientifique, UMR 5287, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, Pessac, France
| | - Cécile Viollet
- Inserm, UMR 894, Center for Psychiatry & Neuroscience, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Jacques Epelbaum
- Inserm, UMR 894, Center for Psychiatry & Neuroscience, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; UMR 7179 CNRS MNHN - MECADEV, 91800 Brunoy, France
| | - Gaëlle Dominguez
- Centre National de la Recherche Scientifique, UMR 5287, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, Pessac, France
| | - Daniel Béracochéa
- Université de Bordeaux, Pessac, France; Centre National de la Recherche Scientifique, UMR 5287, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, Pessac, France
| | - Jean-Louis Guillou
- Université de Bordeaux, Pessac, France; Centre National de la Recherche Scientifique, UMR 5287, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, Pessac, France.
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17
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Tran T, Gallagher M, Kirkwood A. Enhanced postsynaptic inhibitory strength in hippocampal principal cells in high-performing aged rats. Neurobiol Aging 2018; 70:92-101. [PMID: 30007169 DOI: 10.1016/j.neurobiolaging.2018.06.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 05/28/2018] [Accepted: 06/03/2018] [Indexed: 11/20/2022]
Abstract
Hyperactivity within the hippocampal formation, frequently observed in aged individuals, is thought to be a potential contributing mechanism to the memory decline often associated with aging. Consequently, we evaluated the postsynaptic strength of excitatory and inhibitory synapses in the granule cells of the dentate gyrus and CA1 pyramidal cells of a rat model of aging, in which each individual was behaviorally characterized as aged impaired (AI) or aged unimpaired (AU, with performance comparable to young (Y) individuals). In hippocampal slices of these 3 aged groups (Y, AI, AU), we found that compared to the young, the miniature excitatory and inhibitory currents (mEPSCs and mIPSCs) were larger in amplitude in the granule cells of the AU group and smaller in the AI group. In contrast, in CA1 cells, neither the mEPSCs nor the mIPSCs were affected by age, whereas the extrasynaptic conductance responsible for tonic inhibition was selectively enhanced in CA1 cells of AU individuals. Tonic inhibition conductance was not affected by age in the granule cells. These results support the notion that upregulation of synaptic inhibition could be a necessary condition for the maintenance of performance during aging. These findings also underscore the notions that successful aging requires adaptive upregulation, not merely the preservation of youthful functionality, and that age effects are not homogeneous across hippocampal subfields.
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Affiliation(s)
- Trinh Tran
- Mind/Brain Institute and Department of Neurosciences, Johns Hopkins University, 3400 N. Charles St, Baltimore, MD 21218, USA
| | - Michela Gallagher
- Department of Psychological and Brain Sciences, Johns Hopkins University, 3400 N. Charles St, Baltimore, MD 21218, USA.
| | - Alfredo Kirkwood
- Mind/Brain Institute and Department of Neurosciences, Johns Hopkins University, 3400 N. Charles St, Baltimore, MD 21218, USA.
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18
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Hoeijmakers L, Amelianchik A, Verhaag F, Kotah J, Lucassen PJ, Korosi A. Early-Life Stress Does Not Aggravate Spatial Memory or the Process of Hippocampal Neurogenesis in Adult and Middle-Aged APP/PS1 Mice. Front Aging Neurosci 2018; 10:61. [PMID: 29563870 PMCID: PMC5845884 DOI: 10.3389/fnagi.2018.00061] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 02/20/2018] [Indexed: 01/13/2023] Open
Abstract
Life-time experiences are thought to influence the risk to develop the neurodegenerative disorder Alzheimer’s disease (AD). In particular, early-life stress (ES) may modulate the onset and progression of AD. There is recent evidence by our group and others that AD-related neuropathological progression and the associated neuroimmune responses are modulated by ES in the classic APPswe/PS1dE9 mouse model for AD. We here extend our previous study on ES mediated modulation of neuropathology and neuroinflammation and address in the same cohort of mice whether ES accelerates and/or aggravates AD-induced cognitive decline and alterations in the process of adult hippocampal neurogenesis (AHN), a form of brain plasticity. Chronic ES was induced by limiting bedding and nesting material during the first postnatal week and is known to induce cognitive deficits by 4 months in wild type (WT) mice. The onset of cognitive decline in APP/PS1 mice generally starts around 6 months of age. We here tested mice at ages 2–4 months to study acceleration and at ages 8–10 months for aggravation of the APP/PS1 phenotype. ES-exposed WT and APP/PS1 mice were able to perform the object recognition (ORT) and location tasks (OLT) at 2 months of age. Interestingly, at 3 months, ES induced impairments in the performance of the OLT in WT, but not in APP/PS1 mice. APP/PS1 mice exhibited alterations in hippocampal cell proliferation and differentiation, but ES exposure did not further change this. At 9 months, APP/PS1 mice exhibited impaired performance in the Morris Water Maze (MWM) task, as well as reductions in markers of the AHN process, which were not further modulated by ES exposure. In addition, we observed a so far unreported hyperactivity in ES-exposed mice at 8 months of age, which hampered assessment of cognitive functions in the ORT and OLT. In conclusion, while ES has been reported to modulate AD neuropathology and neuroinflammation before, it failed to accelerate or aggravate the decline in cognition or the process of AHN in APP/PS1 mice at ages 2–4 and 8–10 months. Future studies are needed to unravel how ES might affect the vulnerability to develop AD.
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Affiliation(s)
- Lianne Hoeijmakers
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Anna Amelianchik
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Fleur Verhaag
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Janssen Kotah
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Paul J Lucassen
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - A Korosi
- Brain Plasticity Group, Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
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Zhao JL, Zhao YY, Zhu WJ. A high-fat, high-protein diet attenuates the negative impact of casein-induced chronic inflammation on testicular steroidogenesis and sperm parameters in adult mice. Gen Comp Endocrinol 2017; 252:48-59. [PMID: 28743557 DOI: 10.1016/j.ygcen.2017.07.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 06/30/2017] [Accepted: 07/16/2017] [Indexed: 12/16/2022]
Abstract
The interaction between obesity and chronic inflammation has been studied. Diet-induced obesity or chronic inflammation could reduce the testicular functions of males. However, the mechanism underlying the reproductive effects of fattening foods in males with or without chronic inflammation still needs further discussion. This study was aimed to investigate the effects of high-fat, high-protein diet on testicular steroidogenesis and sperm parameters in adult mice under physiological and chronic inflammatory conditions. Because casein can trigger a non-infectious systemic inflammatory response, we used casein injection to induce chronic inflammation in male adult Kunming mice. Twenty-four mice were randomly and equally divided into four groups: (i) normal diet+saline (Control); (ii) normal diet+casein (ND+CS); (iii) high-fat, high-protein diet+saline (HFPD+SI); (iv) high-fat, high-protein diet+casein (HFPD+CS). After 8weeks, there was a significant increase in body weight for groups HFPD+SI and HFPD+CS and a decrease in group ND+CS compared with the control. The serum levels of tumor necrosis factor alpha (TNF-α), interleukin-10 (IL-10) and lipid profiles were increased markedly in groups ND+CS, HFPD+SI and HFPD+CS compared with the control. A remarkable reduction of serum adiponectin level occurred in group HFPD+CS compared with group ND+CS. Sperm parameters (sperm count, viability and abnormality) were also adversely affected in groups ND+CS and HFPD+SI. Groups ND+CS and HFPD+SI showed severe pathological changes in testicular tissues. Semiquantitative RT-PCR, Western blot and immunohistochemical staining also showed significant reductions in both testicular mRNA and protein levels of steroidogenic acute regulatory (StAR) and cytochrome P450scc (CYP11A1) in groups HFPD+SI and HFPD+CS compared with the control, whereas testicular mRNA and protein levels of 3β-hydroxysteroid dehydrogenase (3β-HSD) in groups HFPD+SI and HFPD+CS significantly increased. The mRNA and protein levels of the StAR and 3β-HSD in group HFPD+CS were both higher than those of in group ND+CS. These results indicated that Kunming male mice with high-fat, high-protein diet and casein injection for 8weeks can be used to establish a diet-induced obesity and chronic systemic inflammation. The sperm parameters in groups ND+CS and HFPD+SI decreased accompanied by pathological changes of testicular tissue. This resultant effect of reduced serum testosterone levels was associated with the overproduction of TNF-α and IL-10 and down-regulation of StAR and CYP11A1. Under the same casein-induced chronic inflammation condition, the mice with high-fat, high-protein diet had better testicular steroidogenesis activity and sperm parameters compared with the mice in normal diet, indicating that the mice with casein-induced inflammatory injury consuming a high-fat, high-protein diet gained weight normally, reduced serum adiponectin level and increased testosterone production by an upregulation of 3β-HSD expression. High-fat, high-protein diet attenuated the negative impact of casein-induced chronic inflammation on testicular steroidogenesis and sperm parameters.
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Affiliation(s)
- Jing-Lu Zhao
- Department of Developmental and Regenerative Biology, College of Life Science and Technology, Jinan University, Guangdong, Guangzhou 510632, China
| | - Yu-Yun Zhao
- College of Chemical and Biological Engineering, Hunan University of Science and Engineering, Hunan, Yongzhou 425199, China
| | - Wei-Jie Zhu
- Department of Developmental and Regenerative Biology, College of Life Science and Technology, Jinan University, Guangdong, Guangzhou 510632, China.
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20
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Kõks S, Dogan S, Tuna BG, González-Navarro H, Potter P, Vandenbroucke RE. Mouse models of ageing and their relevance to disease. Mech Ageing Dev 2016; 160:41-53. [PMID: 27717883 DOI: 10.1016/j.mad.2016.10.001] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 09/26/2016] [Accepted: 10/03/2016] [Indexed: 12/28/2022]
Abstract
Ageing is a process that gradually increases the organism's vulnerability to death. It affects different biological pathways, and the underlying cellular mechanisms are complex. In view of the growing disease burden of ageing populations, increasing efforts are being invested in understanding the pathways and mechanisms of ageing. We review some mouse models commonly used in studies on ageing, highlight the advantages and disadvantages of the different strategies, and discuss their relevance to disease susceptibility. In addition to addressing the genetics and phenotypic analysis of mice, we discuss examples of models of delayed or accelerated ageing and their modulation by caloric restriction.
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Affiliation(s)
- Sulev Kõks
- University of Tartu, Tartu, Estonia and Estonian University of Life Sciences, Tartu, Estonia.
| | - Soner Dogan
- Yeditepe University, School of Medicine, Department of Medical Biology, Istanbul, Turkey.
| | - Bilge Guvenc Tuna
- Yeditepe University, School of Medicine, Department of Biophysics, Istanbul, Turkey.
| | - Herminia González-Navarro
- Institute of Health Research-INCLIVA, 46010 Valencia, Spain and CIBER de Diabetes y Enfermedades Metabólicas (CIBERDEM), 28029 Madrid, Spain.
| | - Paul Potter
- Mammalian Genetics Unit, MRC Harwell, Oxfordshire, UK.
| | - Roosmarijn E Vandenbroucke
- Inflammation Research Center, VIB, Ghent, Belgium, Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
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21
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Exercise prevents high-fat diet-induced impairment of flexible memory expression in the water maze and modulates adult hippocampal neurogenesis in mice. Neurobiol Learn Mem 2016; 131:26-35. [DOI: 10.1016/j.nlm.2016.03.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 02/21/2016] [Accepted: 03/02/2016] [Indexed: 02/05/2023]
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22
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Neurocognitive Aging and the Hippocampus across Species. Trends Neurosci 2015; 38:800-812. [PMID: 26607684 DOI: 10.1016/j.tins.2015.10.003] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 09/27/2015] [Accepted: 10/18/2015] [Indexed: 11/23/2022]
Abstract
There is extensive evidence that aging is associated with impairments in episodic memory. Many of these changes have been ascribed to neurobiological alterations to the hippocampal network and its input pathways. A cross-species consensus is beginning to emerge suggesting that subtle synaptic and functional changes within this network may underlie the majority of age-related memory impairments. In this review we survey convergent data from animal and human studies that have contributed significantly to our understanding of the brain-behavior relationships in this network, particularly in the aging brain. We utilize a cognitive as well as a neurobiological perspective and synthesize data across approaches and species to reach a more detailed understanding of age-related alterations in hippocampal memory function.
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23
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Brust V, Schindler PM, Lewejohann L. Lifetime development of behavioural phenotype in the house mouse (Mus musculus). Front Zool 2015; 12 Suppl 1:S17. [PMID: 26816516 PMCID: PMC4722345 DOI: 10.1186/1742-9994-12-s1-s17] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
With each trajectory taken during the ontogeny of an individual, the number of optional behavioural phenotypes that can be expressed across its life span is reduced. The initial range of phenotypic plasticity is largely determined by the genetic material/composition of the gametes whereas interacting with the given environment shapes individuals to adapt to/cope with specific demands. In mammalian species, the phenotype is shaped as the foetus grows, depending on the environment in the uterus, which in turn depends on the outer environment the mother experiences during pregnancy. After birth, a complex interaction between innate constitution and environmental conditions shapes individual lifetime trajectories, bringing about a wide range of diversity among individual subjects. In laboratory mice inbreeding has been systematically induced in order to reduce the genetic variability between experimental subjects. In addition, within most laboratories conducting behavioural phenotyping with mice, breeding and housing conditions are highly standardised. Despite such standardisation efforts a considerable amount of variability persists in the behaviour of mice. There is good evidence that phenotypic variation is not merely random but might involve individual specific behavioural patterns consistent over time. In order to understand the mechanisms and the possible adaptive value of the maintenance of individuality we review the emergence of behavioural phenotypes over the course of the life of (laboratory) mice. We present a literature review summarizing developmental stages of behavioural development of mice along with three illustrative case studies. We conclude that the accumulation of environmental differences and experiences lead to a “mouse individuality” that becomes increasingly stable over the lifetime.
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Affiliation(s)
- Vera Brust
- Behavioral Biology, University of Osnabrueck, Barbarastrasse 11, 49076 Osnabrueck, Germany
| | - Philipp M Schindler
- Behavioral Biology, University of Osnabrueck, Barbarastrasse 11, 49076 Osnabrueck, Germany
| | - Lars Lewejohann
- Behavioral Biology, University of Osnabrueck, Barbarastrasse 11, 49076 Osnabrueck, Germany
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Lucas SJ, Armstrong DL. Protein phosphatase modulation of somatostatin receptor signaling in the mouse hippocampus. Neuropharmacology 2015. [PMID: 26196943 DOI: 10.1016/j.neuropharm.2015.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Many inhibitory interneurones in the hippocampus release the neuropeptide somatostatin (SST) which inhibits neuronal excitability through Gi/Go-coupled receptors. To investigate the signaling pathways underlying the SST inhibition of neuronal excitability in the hippocampus, we performed perforated patch-clamp recordings from CA1 pyramidal neurones in acute brain slices from P14-P18 mice. Bath application of 1 μM SST reversibly reduces the frequency of action potential firing in response to depolarising current steps, and is associated with neuronal hyperpolarisation and a reduction in membrane resistance. This effect is mediated by potassium channels with KCNK-like pharmacology. In addition, in slices that have been cultured in vitro for seven days or more, SST also produces a hyperpolarisation independent reduction in action potential firing, which can be also observed in acute slices when the Ser/Thr protein phosphatases PP2A and PP4 are inhibited selectively with fostriecin. This hyperpolarisation independent effect of SST appears to be mediated by G-protein-activated inwardly rectifying K+ (GIRK) channels. Knockdown of protein phosphatase 5, by Cre recombinase mediated deletion of the floxed Ppp5c gene, blocks the hyperpolarisation independent effect of SST, and reduces the hyperpolarisation dependent effect in a manner consistent with increased SST receptor desensitisation. Thus, reversible protein phosphorylation provides a mechanism to enhance or diminish the inhibitory effect of SST, which could allow system level regulation of circuit excitability in the hippocampus.
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Affiliation(s)
- Sarah J Lucas
- Lab. Neurobiology, National Institute of Environmental Health Sciences, NIH, Durham, NC, 27709, USA.
| | - David L Armstrong
- Lab. Neurobiology, National Institute of Environmental Health Sciences, NIH, Durham, NC, 27709, USA
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Tong LM, Fong H, Huang Y. Stem cell therapy for Alzheimer's disease and related disorders: current status and future perspectives. Exp Mol Med 2015; 47:e151. [PMID: 25766620 PMCID: PMC4351411 DOI: 10.1038/emm.2014.124] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 11/19/2014] [Indexed: 12/31/2022] Open
Abstract
Underlying cognitive declines in Alzheimer's disease (AD) are the result of neuron and neuronal process losses due to a wide range of factors. To date, all efforts to develop therapies that target specific AD-related pathways have failed in late-stage human trials. As a result, an emerging consensus in the field is that treatment of AD patients with currently available drug candidates might come too late, likely as a result of significant neuronal loss in the brain. In this regard, cell-replacement therapies, such as human embryonic stem cell- or induced pluripotent stem cell-derived neural cells, hold potential for treating AD patients. With the advent of stem cell technologies and the ability to transform these cells into different types of central nervous system neurons and glial cells, some success in stem cell therapy has been reported in animal models of AD. However, many more steps remain before stem cell therapies will be clinically feasible for AD and related disorders in humans. In this review, we will discuss current research advances in AD pathogenesis and stem cell technologies; additionally, the potential challenges and strategies for using cell-based therapies for AD and related disorders will be discussed.
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Affiliation(s)
- Leslie M Tong
- Gladstone Institute of Neurological Disease, University of California, San Francisco, CA, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, CA, USA
| | - Helen Fong
- Gladstone Institute of Neurological Disease, University of California, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, CA, USA
| | - Yadong Huang
- Gladstone Institute of Neurological Disease, University of California, San Francisco, CA, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, CA, USA
- Department of Pathology, University of California, San Francisco, CA, USA
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Apolipoprotein E4 produced in GABAergic interneurons causes learning and memory deficits in mice. J Neurosci 2015; 34:14069-78. [PMID: 25319703 DOI: 10.1523/jneurosci.2281-14.2014] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Apolipoprotein (apo) E4 is expressed in many types of brain cells, is associated with age-dependent decline of learning and memory in humans, and is the major genetic risk factor for AD. To determine whether the detrimental effects of apoE4 depend on its cellular sources, we generated human apoE knock-in mouse models in which the human APOE gene is conditionally deleted in astrocytes, neurons, or GABAergic interneurons. Here we report that deletion of apoE4 in astrocytes does not protect aged mice from apoE4-induced GABAergic interneuron loss and learning and memory deficits. In contrast, deletion of apoE4 in neurons does protect aged mice from both deficits. Furthermore, deletion of apoE4 in GABAergic interneurons is sufficient to gain similar protection. This study demonstrates a detrimental effect of endogenously produced apoE4 on GABAergic interneurons that leads to learning and memory deficits in mice and provides a novel target for drug development for AD related to apoE4.
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Prenderville JA, Kennedy PJ, Dinan TG, Cryan JF. Adding fuel to the fire: the impact of stress on the ageing brain. Trends Neurosci 2015; 38:13-25. [DOI: 10.1016/j.tins.2014.11.001] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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