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Rao S, Liang F, Herring BE. RhoGEF Tiam2 Regulates Glutamatergic Synaptic Transmission in Hippocampal CA1 Pyramidal Neurons. eNeuro 2024; 11:ENEURO.0500-21.2024. [PMID: 38871458 PMCID: PMC11262554 DOI: 10.1523/eneuro.0500-21.2024] [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: 12/03/2021] [Revised: 03/29/2024] [Accepted: 05/23/2024] [Indexed: 06/15/2024] Open
Abstract
Glutamatergic synapses exhibit significant molecular diversity, but circuit-specific mechanisms that underlie synaptic regulation are not well characterized. Prior reports show that Rho-guanine nucleotide exchange factor (RhoGEF) Tiam1 regulates perforant path→dentate gyrus granule neuron synapses. In the present study, we report Tiam1's homolog Tiam2 is implicated in glutamatergic neurotransmission in CA1 pyramidal neurons. We find that Tiam2 regulates evoked excitatory glutamatergic currents via a postsynaptic mechanism mediated by the catalytic Dbl-homology domain. Overall, we present evidence for RhoGEF Tiam2's role in glutamatergic synapse function at Schaffer collateral→CA1 pyramidal neuron synapses.
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Affiliation(s)
- Sadhna Rao
- Department of Biological Sciences, Neurobiology Section, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California 90089
| | - Feng Liang
- Department of Biological Sciences, Neurobiology Section, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California 90089
| | - Bruce E Herring
- Department of Biological Sciences, Neurobiology Section, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California 90089
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2
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Haast RAM, Kashyap S, Ivanov D, Yousif MD, DeKraker J, Poser BA, Khan AR. Insights into hippocampal perfusion using high-resolution, multi-modal 7T MRI. Proc Natl Acad Sci U S A 2024; 121:e2310044121. [PMID: 38446857 PMCID: PMC10945835 DOI: 10.1073/pnas.2310044121] [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: 06/19/2023] [Accepted: 12/26/2023] [Indexed: 03/08/2024] Open
Abstract
We present a comprehensive study on the non-invasive measurement of hippocampal perfusion. Using high-resolution 7 tesla arterial spin labeling (ASL) data, we generated robust perfusion maps and observed significant variations in perfusion among hippocampal subfields, with CA1 exhibiting the lowest perfusion levels. Notably, these perfusion differences were robust and already detectable with 50 perfusion-weighted images per subject, acquired in 5 min. To understand the underlying factors, we examined the influence of image quality metrics, various tissue microstructure and morphometric properties, macrovasculature, and cytoarchitecture. We observed higher perfusion in regions located closer to arteries, demonstrating the influence of vascular proximity on hippocampal perfusion. Moreover, ex vivo cytoarchitectonic features based on neuronal density differences appeared to correlate stronger with hippocampal perfusion than morphometric measures like gray matter thickness. These findings emphasize the interplay between microvasculature, macrovasculature, and metabolic demand in shaping hippocampal perfusion. Our study expands the current understanding of hippocampal physiology and its relevance to neurological disorders. By providing in vivo evidence of perfusion differences between hippocampal subfields, our findings have implications for diagnosis and potential therapeutic interventions. In conclusion, our study provides a valuable resource for extensively characterizing hippocampal perfusion.
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Affiliation(s)
- Roy A. M. Haast
- Centre of Functional and Metabolic Mapping, Robarts Research Institute, Western University, London, ONN6A 3K7, Canada
| | - Sriranga Kashyap
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht6200, The Netherlands
- Krembil Brain Institute, University Health Network, Toronto, ONM5G 2C4, Canada
| | - Dimo Ivanov
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht6200, The Netherlands
| | - Mohamed D. Yousif
- Centre of Functional and Metabolic Mapping, Robarts Research Institute, Western University, London, ONN6A 3K7, Canada
| | - Jordan DeKraker
- Montreal Neurological Institute and Hospital, McGill University, Montreal, QCH3A 0G4, Canada
| | - Benedikt A. Poser
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht6200, The Netherlands
| | - Ali R. Khan
- Centre of Functional and Metabolic Mapping, Robarts Research Institute, Western University, London, ONN6A 3K7, Canada
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3
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Einenkel AM, Salameh A. Selective vulnerability of hippocampal CA1 and CA3 pyramidal cells: What are possible pathomechanisms and should more attention be paid to the CA3 region in future studies? J Neurosci Res 2024; 102:e25276. [PMID: 38284845 DOI: 10.1002/jnr.25276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/22/2023] [Accepted: 10/29/2023] [Indexed: 01/30/2024]
Abstract
Transient ischemia and reperfusion selectively damage neurons in brain, with hippocampal pyramidal cells being particularly vulnerable. Even within hippocampus, heterogeneous susceptibility is evident, with higher vulnerability of CA1 versus CA3 neurons described for several decades. Therefore, numerous studies have focused exclusively on CA1. Pediatric cardiac surgery is increasingly focusing on studies of hippocampal structures, and a negative impact of cardiopulmonary bypass on the hippocampus cannot be denied. Recent studies show a shift in selective vulnerability from neurons of CA1 to CA3. This review shows that cell damage is increased in CA3, sometimes stronger than in CA1, depending on several factors (method, species, age, observation period). Despite a highly variable pattern, several markers illustrate greater damage to CA3 neurons than previously assumed. Nevertheless, the underlying cellular mechanisms have not been fully deciphered to date. The complexity is reflected in possible pathomechanisms discussed here, with numerous factors (NMDA, kainate and AMPA receptors, intrinsic oxidative stress potential and various radicals, AKT isoforms, differences in vascular architecture, ratio of pro- and anti-apoptotic Bcl-2 factors, vulnerability of interneurons, mitochondrial dysregulation) contributing to either enhanced CA1 or CA3 vulnerability. Furthermore, differences in expressed genome, proteome, metabolome, and transcriptome in CA1 and CA3 appear to influence differential behavior after damaging stimuli, thus metabolomics-, transcriptomics-, and proteomics-based analyses represent a viable option to identify pathways of selective vulnerability in hippocampal neurons. These results emphasize that future studies should focus on the CA3 field in addition to CA1, especially with regard to improving therapeutic strategies after ischemic/hypoxic brain injury.
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Affiliation(s)
- Anne-Marie Einenkel
- Clinic for Pediatric Cardiology, University of Leipzig, Heart Centre, Leipzig, Germany
| | - Aida Salameh
- Clinic for Pediatric Cardiology, University of Leipzig, Heart Centre, Leipzig, Germany
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4
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Haast RAM, Kashyap S, Ivanov D, Yousif MD, DeKraker J, Poser BA, Khan AR. Novel insights into hippocampal perfusion using high-resolution, multi-modal 7T MRI. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.19.549533. [PMID: 37503042 PMCID: PMC10370151 DOI: 10.1101/2023.07.19.549533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
We present a comprehensive study on the non-invasive measurement of hippocampal perfusion. Using high-resolution 7 Tesla arterial spin labelling data, we generated robust perfusion maps and observed significant variations in perfusion among hippocampal subfields, with CA1 exhibiting the lowest perfusion levels. Notably, these perfusion differences were robust and detectable even within five minutes and just fifty perfusion-weighted images per subject. To understand the underlying factors, we examined the influence of image quality metrics, various tissue microstructure and morphometry properties, macrovasculature and cytoarchitecture. We observed higher perfusion in regions located closer to arteries, demonstrating the influence of vascular proximity on hippocampal perfusion. Moreover, ex vivo cytoarchitectonic features based on neuronal density differences appeared to correlate stronger with hippocampal perfusion than morphometric measures like gray matter thickness. These findings emphasize the interplay between microvasculature, macrovasculature, and metabolic demand in shaping hippocampal perfusion. Our study expands the current understanding of hippocampal physiology and its relevance to neurological disorders. By providing in vivo evidence of perfusion differences between hippocampal subfields, our findings have implications for diagnosis and potential therapeutic interventions. In conclusion, our study provides a valuable resource for extensively characterising hippocampal perfusion.
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Affiliation(s)
- Roy A M Haast
- Centre of Functional and Metabolic Mapping, Western University, London, Ontario, Canada
| | - Sriranga Kashyap
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
- Krembil Brain Institute, University Health Network, Toronto, Ontario, Canada
| | - Dimo Ivanov
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Mohamed D Yousif
- Centre of Functional and Metabolic Mapping, Western University, London, Ontario, Canada
| | - Jordan DeKraker
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Benedikt A Poser
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Ali R Khan
- Centre of Functional and Metabolic Mapping, Western University, London, Ontario, Canada
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5
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Handwerk CJ, Bland KM, Denzler CJ, Kalinowski AR, Brett CA, Swinehart BD, Rodriguez HV, Cook HN, Vinson EC, Florenz ME, Vidal GS. Simultaneous 3D cellular positioning and apical dendritic morphology of transgenic fluorescent mouse CA3 hippocampal pyramidal neurons. J Neurosci Methods 2023; 388:109823. [PMID: 36809825 PMCID: PMC10006342 DOI: 10.1016/j.jneumeth.2023.109823] [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: 08/12/2022] [Revised: 01/31/2023] [Accepted: 02/17/2023] [Indexed: 02/21/2023]
Abstract
BACKGROUND Pyramidal neurons throughout hippocampal CA3 are diverse in their dendritic morphology, and CA3 is not homogenous in its structure or function. Nonetheless, few structural studies have captured the precise 3D somatic position and the 3D dendritic morphology of CA3 pyramidal neurons simultaneously. NEW METHOD Here, we present a simple approach to reconstruct the apical dendritic morphology of CA3 pyramidal neurons using the transgenic fluorescent Thy1-GFP-M line. The approach simultaneously tracks the dorsoventral, tangential, and radial positions of reconstructed neurons within the hippocampus. It is especially designed for use with transgenic fluorescent mouse lines, which are commonly used in genetic studies of neuronal morphology and development. RESULTS We demonstrate how topographic and morphological data are captured from transgenic fluorescent mouse CA3 pyramidal neurons. COMPARISON WITH EXISTING METHODS There is no need to select and label CA3 pyramidal neurons with the transgenic fluorescent Thy1-GFP-M line. By taking transverse (not coronal) serial sections, we preserve fine dorsoventral, tangential, and radial somatic positioning of 3D-reconstructed neurons. Because CA2 is well defined by PCP4 immunohistochemistry, we use that technique here to to increase precision in defining tangential position along CA3. CONCLUSIONS We developed a method for simultaneously collecting precise somatic positioning as well as 3D morphological data among transgenic fluorescent mouse hippocampal pyramidal neurons. This fluorescent method should be compatible with many other transgenic fluorescent reporter lines and immunohistochemical methods, facilitating the capture of topographic and morphological data from a wide variety of genetic experiments in mouse hippocampus.
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Affiliation(s)
- Christopher J Handwerk
- Department of Biology, James Madison University, MSC 7801, Harrisonburg, VA 22807, United States of America
| | - Katherine M Bland
- Department of Biology, James Madison University, MSC 7801, Harrisonburg, VA 22807, United States of America
| | - Collin J Denzler
- Department of Biology, James Madison University, MSC 7801, Harrisonburg, VA 22807, United States of America
| | - Anna R Kalinowski
- Department of Biology, James Madison University, MSC 7801, Harrisonburg, VA 22807, United States of America
| | - Cooper A Brett
- Department of Biology, James Madison University, MSC 7801, Harrisonburg, VA 22807, United States of America
| | - Brian D Swinehart
- Department of Biology, James Madison University, MSC 7801, Harrisonburg, VA 22807, United States of America
| | - Hilda V Rodriguez
- Department of Biology, James Madison University, MSC 7801, Harrisonburg, VA 22807, United States of America
| | - Hollyn N Cook
- Department of Biology, James Madison University, MSC 7801, Harrisonburg, VA 22807, United States of America
| | - Elizabeth C Vinson
- Department of Biology, James Madison University, MSC 7801, Harrisonburg, VA 22807, United States of America
| | - Madison E Florenz
- Department of Biology, James Madison University, MSC 7801, Harrisonburg, VA 22807, United States of America
| | - George S Vidal
- Department of Biology, James Madison University, MSC 7801, Harrisonburg, VA 22807, United States of America.
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6
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Dudek SM, Alexander GM, Farris S. Introduction to the special issue on: A new view of hippocampal area CA2. Hippocampus 2023; 33:127-132. [PMID: 36826426 DOI: 10.1002/hipo.23514] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2023] [Indexed: 02/25/2023]
Affiliation(s)
- Serena M Dudek
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institute of Health, Research Triangle Park, North Carolina, USA
| | - Georgia M Alexander
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institute of Health, Research Triangle Park, North Carolina, USA
| | - Shannon Farris
- Center for Neurobiology Research, Fralin Biomedical Research Institute, Virginia Tech Carilion, Roanoke, Virginia, USA
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7
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Marosi EL, Arszovszki A, Brunner J, Szabadics J. Similar Presynaptic Action Potential-Calcium Influx Coupling in Two Types of Large Mossy Fiber Terminals Innervating CA3 Pyramidal Cells and Hilar Mossy Cells. eNeuro 2023; 10:ENEURO.0017-23.2023. [PMID: 36697256 PMCID: PMC9907395 DOI: 10.1523/eneuro.0017-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 01/16/2023] [Indexed: 01/26/2023] Open
Abstract
Morphologically similar axon boutons form synaptic contacts with diverse types of postsynaptic cells. However, it is less known to what extent the local axonal excitability, presynaptic action potentials (APs), and AP-evoked calcium influx contribute to the functional diversity of synapses and neuronal activity. This is particularly interesting in synapses that contact cell types that show only subtle cellular differences but fulfill completely different physiological functions. Here, we tested these questions in two synapses that are formed by rat hippocampal granule cells (GCs) onto hilar mossy cells (MCs) and CA3 pyramidal cells, which albeit share several morphologic and synaptic properties but contribute to distinct physiological functions. We were interested in the deterministic steps of the action potential-calcium ion influx coupling as these complex modules may underlie the functional segregation between and within the two cell types. Our systematic comparison using direct axonal recordings showed that AP shapes, Ca2+ currents and their plasticity are indistinguishable in synapses onto these two cell types. These suggest that the complete module that couples granule cell activity to synaptic release is shared by hilar mossy cells and CA3 pyramidal cells. Thus, our findings present an outstanding example for the modular composition of distinct cell types, by which cells employ different components only for those functions that are deterministic for their specialized functions, while many of their main properties are shared.
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Affiliation(s)
| | | | - János Brunner
- Institute of Experimental Medicine, Budapest, 1083, Hungary
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8
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Machado JP, Athie MC, Matos AH, Lopes-Cendes I, Vieira A. The transcriptome of rat hippocampal subfields. IBRO Neurosci Rep 2022; 13:322-329. [PMID: 36247526 PMCID: PMC9561749 DOI: 10.1016/j.ibneur.2022.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 11/08/2022] Open
Abstract
The hippocampus comprises several neuronal populations such as CA1, CA2, CA3, and the dentate gyrus (DG), which present different neuronal origins, morphologies, and molecular mechanisms. Laser capture microdissection (LCM) allows selectively collecting samples from target regions and eliminating unwanted cells to obtain more specific results. LCM of hippocampus neuronal populations coupĺed with RNA-seq analysis has the potential to allow the exploration of the molecular machinery unique to each of these subfields. Previous RNA-seq investigation has already provided a molecular blueprint of the hippocampus, however, there is no RNA-seq data specific for each of the rat hippocampal regions. Serial tissue sections covering the hippocampus were produced from frozen brains of adult male Wistar rats, and the hippocampal subfields CA1, CA2, CA3, and DG were identified and isolated by LCM. We found evident segregation of the transcriptomic profile from different regions of the hippocampus and the expression of known, as well as novel, specific marker genes for each region. Gene ontology enrichment analysis of CA1 subfield indicates an enrichment of actin regulation and postsynaptic membrane AMPA receptors genes indispensable for long-term potentiation. CA2 and CA3 transcripts were found associated with the increased metabolic processes. DG expression was enriched for ribosome and spliceosome, both required for protein synthesis and maintenance of cell life. The present findings contribute to a deeper understanding of the differences in the molecular machinery expressed by the rat hippocampal neuronal populations, further exploring underlying mechanisms responsible for each subflied specific functions.
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Affiliation(s)
- João P.D. Machado
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil
| | - Maria C.P. Athie
- Department of Translational Medicine, School of Medical Sciences. University of Campinas (UNICAMP), Campinas, São Paulo, Brazil,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil
| | - Alexandre H.B. Matos
- Department of Translational Medicine, School of Medical Sciences. University of Campinas (UNICAMP), Campinas, São Paulo, Brazil,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil
| | - Iscia Lopes-Cendes
- Department of Translational Medicine, School of Medical Sciences. University of Campinas (UNICAMP), Campinas, São Paulo, Brazil,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil
| | - André.S. Vieira
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil,Correspondence to: Department of Structural and Functional Biology, Institute of Biology, Cidade Universitária “Zeferino Vaz”, University of Campinas, UNICAMP, Rua Monteiro Lobato, 255 - Bloco J - 1 piso - Sl 16, Campinas 13083-862, São Paulo, Brazil.
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9
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Reduction in hippocampal volumes subsequent to heavy cannabis use: a 3-year longitudinal study. Psychiatry Res 2021; 295:113588. [PMID: 33261923 DOI: 10.1016/j.psychres.2020.113588] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 11/18/2020] [Indexed: 11/22/2022]
Abstract
Cannabis exposure is related to neuroanatomical changes in brain regions rich in cannabinoid receptors, such as the hippocampus. However, researchers have not clearly determined whether persistent heavy cannabis use leads to morphological changes in the hippocampus or whether an earlier age of onset of first cannabis use and/or higher doses of cannabis exposure exacerbate these alterations. In this longitudinal study, we investigated whether continued heavy cannabis use in young adults is associated with an altered hippocampal volume. Twenty heavy cannabis users (CBs) and 22 healthy controls (HCs) underwent a comprehensive psychological assessment and a T1 structural scan at baseline and at a 3-year follow-up visit. Volumes of the hippocampus and its subregions were estimated using volBrain software. Except for the cornu ammonis 2 (CA2)/CA3 subregions, age had significant effects on all hippocampal subregions in both the CB and HC groups. The relative right hippocampal volume and absolute and relative right CA1 volumes displayed a greater rate of decrease in CBs compared to HCs. In addition, we explored the relationship between alterations in hippocampal volume and cannabis use characteristics. Changes in the relative right hippocampal volume and the relative right CA1 volume were related to age at first cannabis use but not to age at onset of frequent cannabis use. Alterations in the relative right hippocampal volume and absolute and relative right CA1 volumes were associated with Cannabis Use Disorder Identification Test (CUDIT) scores. Based on these results, heavy cannabis use in early adulthood is a risk factor for a greater rate of decrease in the volume of the right hippocampus (particularly the right CA1).
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10
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Lothmann K, Deitersen J, Zilles K, Amunts K, Herold C. New boundaries and dissociation of the mouse hippocampus along the dorsal-ventral axis based on glutamatergic, GABAergic and catecholaminergic receptor densities. Hippocampus 2020; 31:56-78. [PMID: 32986281 DOI: 10.1002/hipo.23262] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 08/31/2020] [Accepted: 09/05/2020] [Indexed: 02/01/2023]
Abstract
In rodents, gene-expression, neuronal tuning, connectivity and neurogenesis studies have postulated that the dorsal, the intermediate and the ventral hippocampal formation (HF) are distinct entities. These findings are underpinned by behavioral studies showing a dissociable role of dorsal and ventral HF in learning, memory, stress and emotional processing. However, up to now, the molecular basis of such differences in relation to discrete boundaries is largely unknown. Therefore, we analyzed binding site densities for glutamatergic AMPA, NMDA, kainate and mGluR2/3 , GABAergic GABAA (including benzodiazepine binding sites), GABAB , dopaminergic D1/5 and noradrenergic α1 and α2 receptors as key modulators for signal transmission in hippocampal functions, using quantitative in vitro receptor autoradiography along the dorsal-ventral axis of the mouse HF. Beside general different receptor profiles of the dentate gyrus (DG) and Cornu Ammonis fields (CA1, CA2, CA3, CA4/hilus), we detected substantial differences between dorsal, intermediate and ventral subdivisions and individual layers for all investigated receptor types, except GABAB . For example, striking higher densities of α2 receptors were detected in the ventral DG, while the dorsal DG possesses higher numbers of kainate, NMDA, GABAA and D1/5 receptors. CA1 dorsal and intermediate subdivisions showed higher AMPA, NMDA, mGluR2/3 , GABAA , D1/5 receptors, while kainate receptors are higher expressed in ventral CA1, and noradrenergic α1 and α2 receptors in the intermediate region of CA1. CA2 dorsal was distinguished by higher kainate, α1 and α2 receptors in the intermediate region, while CA3 showed a more complex dissociation. Our findings resulted not only in a clear segmentation of the mouse hippocampus along the dorsal-ventral axis, but also provides insights into the neurochemical basis and likely associated physiological processes in hippocampal functions. Therein, the presented data has a high impact for future studies modeling and investigating dorsal, intermediate and ventral hippocampal dysfunction in relation to neurodegenerative diseases or psychiatric disorders.
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Affiliation(s)
- Kimberley Lothmann
- C. & O. Vogt-Institute for Brain Research, Medical Faculty, University Clinic Düsseldof, Heinrich Heine University of Düsseldorf, Düsseldorf, Germany
| | - Jana Deitersen
- C. & O. Vogt-Institute for Brain Research, Medical Faculty, University Clinic Düsseldof, Heinrich Heine University of Düsseldorf, Düsseldorf, Germany
| | - Karl Zilles
- Institute of Neuroscience and Medicine INM-1, Research Centre Jülich, 52425, Jülich, Germany
| | - Katrin Amunts
- C. & O. Vogt-Institute for Brain Research, Medical Faculty, University Clinic Düsseldof, Heinrich Heine University of Düsseldorf, Düsseldorf, Germany.,Institute of Neuroscience and Medicine INM-1, Research Centre Jülich, 52425, Jülich, Germany
| | - Christina Herold
- C. & O. Vogt-Institute for Brain Research, Medical Faculty, University Clinic Düsseldof, Heinrich Heine University of Düsseldorf, Düsseldorf, Germany
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11
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Wang ZT, Zhang C, Wang YJ, Dong Q, Tan L, Yu JT. Selective neuronal vulnerability in Alzheimer's disease. Ageing Res Rev 2020; 62:101114. [PMID: 32569730 DOI: 10.1016/j.arr.2020.101114] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 06/04/2020] [Accepted: 06/09/2020] [Indexed: 12/16/2022]
Abstract
Alzheimer's disease (AD) is defined by a deficiency in specific behavioural and/or cognitive domains, pointing to selective vulnerabilities of specific neurons from different brain regions. These vulnerabilities can be compared across neuron subgroups to identify the most vulnerable neuronal types, regions, and time points for further investigation. Thus, the relevant organizational frameworks for brain subgroups will hold great values for a clear understanding of the progression in AD. Presently, the neuronal vulnerability has yet urgently required to be elucidated as not yet been clearly defined. It is suggested that cell-autonomous and non-cell-autonomous mechanisms can affect the neuronal vulnerability to stressors, and in turn modulates AD progression. This review examines cell-autonomous and non-cell-autonomous mechanisms that contribute to the neuronal vulnerability. Collectively, the cell-autonomous mechanisms seem to be the primary drivers responsible for initiating specific stressor-related neuronal vulnerability with pathological changes in certain brain areas, which then utilize non-cell-autonomous mechanisms and result in subsequent progression of AD. In summary, this article has provided a new perspective on the preventative and therapeutic options for AD.
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Affiliation(s)
- Zuo-Teng Wang
- Department of Neurology, Qingdao Municipal Hospital, College of Medicine and Pharmaceutics, Ocean University of China, Qingdao, China
| | - Can Zhang
- Genetics and Aging Research Unit, McCance Center for Brain Health, MassGeneral Institute for Neurodegenerative Diseases (MIND), Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, 02129-2060, USA
| | - Yan-Jiang Wang
- Department of Neurology, Daping Hospital, Third Military Medical University, China
| | - Qiang Dong
- Department of Neurology and Institute of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Lan Tan
- Department of Neurology, Qingdao Municipal Hospital, College of Medicine and Pharmaceutics, Ocean University of China, Qingdao, China; Department of Neurology, Qingdao Municipal Hospital, Qingdao University, Qingdao, China
| | - Jin-Tai Yu
- Department of Neurology and Institute of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
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12
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Hackett MJ, Hollings A, Caine S, Bewer BE, Alaverdashvili M, Takechi R, Mamo JCL, Jones MWM, de Jonge MD, Paterson PG, Pickering IJ, George GN. Elemental characterisation of the pyramidal neuron layer within the rat and mouse hippocampus. Metallomics 2020; 11:151-165. [PMID: 30398510 DOI: 10.1039/c8mt00230d] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A unique combination of sensitivity, resolution, and penetration make X-ray fluorescence imaging (XFI) ideally suited to investigate trace elemental distributions in the biological context. XFI has gained widespread use as an analytical technique in the biological sciences, and in particular enables exciting new avenues of research in the field of neuroscience. In this study, elemental mapping by XFI was applied to characterise the elemental content within neuronal cell layers of hippocampal sub-regions of mice and rats. Although classical histochemical methods for metal detection exist, such approaches are typically limited to qualitative analysis. Specifically, histochemical methods are not uniformly sensitive to all chemical forms of a metal, often displaying variable sensitivity to specific "pools" or chemical forms of a metal. In addition, histochemical methods require fixation and extensive chemical treatment of samples, creating the strong likelihood for metal redistribution, leaching, or contamination. Direct quantitative elemental mapping of total elemental pools, in situ within ex vivo tissue sections, without the need for chemical fixation or addition of staining reagents is not possible with traditional histochemical methods; however, such a capability, which is provided by XFI, can offer an enormous analytical advantage. The results we report herein demonstrate the analytical advantage of XFI elemental mapping for direct, label-free metal quantification, in situ within ex vivo brain tissue sections. Specifically, we definitively characterise for the first time, the abundance of Fe within the pyramidal cell layers of the hippocampus. Localisation of Fe to this cell layer is not reproducibly achieved with classical Perls histochemical Fe stains. The ability of XFI to directly quantify neuronal elemental (P, S, Cl, K, Ca, Fe, Cu, Zn) distributions, revealed unique profiles of Fe and Zn within anatomical sub-regions of the hippocampus i.e., cornu ammonis 1, 2 or 3 (CA1, CA2 or CA3) sub-regions. Interestingly, our study reveals a unique Fe gradient across neuron populations within the non-degenerating and pathology free rat hippocampus, which curiously mirrors the pattern of region-specific vulnerability of the hippocampus that has previously been established to occur in various neurodegenerative diseases.
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Affiliation(s)
- M J Hackett
- Curtin Institute for Functional Molecules and Interfaces, School of Molecular and Life Sciences, Curtin University, GPOBox U1987, Bentley, WA 6845, Australia.
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van der Meer D, Rokicki J, Kaufmann T, Córdova-Palomera A, Moberget T, Alnæs D, Bettella F, Frei O, Doan NT, Sønderby IE, Smeland OB, Agartz I, Bertolino A, Bralten J, Brandt CL, Buitelaar JK, Djurovic S, van Donkelaar M, Dørum ES, Espeseth T, Faraone SV, Fernández G, Fisher SE, Franke B, Haatveit B, Hartman CA, Hoekstra PJ, Håberg AK, Jönsson EG, Kolskår KK, Le Hellard S, Lund MJ, Lundervold AJ, Lundervold A, Melle I, Monereo Sánchez J, Norbom LC, Nordvik JE, Nyberg L, Oosterlaan J, Papalino M, Papassotiropoulos A, Pergola G, de Quervain DJF, Richard G, Sanders AM, Selvaggi P, Shumskaya E, Steen VM, Tønnesen S, Ulrichsen KM, Zwiers MP, Andreassen OA, Westlye LT. Brain scans from 21,297 individuals reveal the genetic architecture of hippocampal subfield volumes. Mol Psychiatry 2020; 25:3053-3065. [PMID: 30279459 PMCID: PMC6445783 DOI: 10.1038/s41380-018-0262-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 08/09/2018] [Accepted: 09/06/2018] [Indexed: 11/09/2022]
Abstract
The hippocampus is a heterogeneous structure, comprising histologically distinguishable subfields. These subfields are differentially involved in memory consolidation, spatial navigation and pattern separation, complex functions often impaired in individuals with brain disorders characterized by reduced hippocampal volume, including Alzheimer's disease (AD) and schizophrenia. Given the structural and functional heterogeneity of the hippocampal formation, we sought to characterize the subfields' genetic architecture. T1-weighted brain scans (n = 21,297, 16 cohorts) were processed with the hippocampal subfields algorithm in FreeSurfer v6.0. We ran a genome-wide association analysis on each subfield, co-varying for whole hippocampal volume. We further calculated the single-nucleotide polymorphism (SNP)-based heritability of 12 subfields, as well as their genetic correlation with each other, with other structural brain features and with AD and schizophrenia. All outcome measures were corrected for age, sex and intracranial volume. We found 15 unique genome-wide significant loci across six subfields, of which eight had not been previously linked to the hippocampus. Top SNPs were mapped to genes associated with neuronal differentiation, locomotor behaviour, schizophrenia and AD. The volumes of all the subfields were estimated to be heritable (h2 from 0.14 to 0.27, all p < 1 × 10-16) and clustered together based on their genetic correlations compared with other structural brain features. There was also evidence of genetic overlap of subicular subfield volumes with schizophrenia. We conclude that hippocampal subfields have partly distinct genetic determinants associated with specific biological processes and traits. Taking into account this specificity may increase our understanding of hippocampal neurobiology and associated pathologies.
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Affiliation(s)
- Dennis van der Meer
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
| | - Jaroslav Rokicki
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway ,grid.5510.10000 0004 1936 8921Department of Psychology, University of Oslo, Oslo, Norway
| | - Tobias Kaufmann
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Aldo Córdova-Palomera
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway ,grid.168010.e0000000419368956Department of Pediatrics, Stanford University School of Medicine, Stanford University, Stanford, USA
| | - Torgeir Moberget
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Dag Alnæs
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Francesco Bettella
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Oleksandr Frei
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Nhat Trung Doan
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Ida E. Sønderby
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Olav B. Smeland
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Ingrid Agartz
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Alessandro Bertolino
- grid.7644.10000 0001 0120 3326Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari Aldo Moro, Bari, Italy ,Azienda Ospedaliero-Universitaria Consorziale Policlinico, Bari, Italy
| | - Janita Bralten
- grid.10417.330000 0004 0444 9382Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands ,grid.5590.90000000122931605Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Christine L. Brandt
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Jan K. Buitelaar
- grid.5590.90000000122931605Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Srdjan Djurovic
- grid.55325.340000 0004 0389 8485Department of Medical Genetics, Oslo University Hospital, Oslo, Norway ,grid.7914.b0000 0004 1936 7443NORMENT, KG Jebsen Centre for Psychosis Research, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Marjolein van Donkelaar
- grid.10417.330000 0004 0444 9382Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands ,grid.5590.90000000122931605Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Erlend S. Dørum
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway ,grid.5510.10000 0004 1936 8921Department of Psychology, University of Oslo, Oslo, Norway ,grid.416731.60000 0004 0612 1014Sunnaas Rehabilitation Hospital HT, Nesodden, Norway
| | - Thomas Espeseth
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway ,grid.5510.10000 0004 1936 8921Department of Psychology, University of Oslo, Oslo, Norway
| | - Stephen V. Faraone
- grid.411023.50000 0000 9159 4457Departments of Psychiatry and of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY USA
| | - Guillén Fernández
- grid.5590.90000000122931605Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Simon E. Fisher
- grid.5590.90000000122931605Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands ,grid.419550.c0000 0004 0501 3839Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, Netherlands
| | - Barbara Franke
- grid.10417.330000 0004 0444 9382Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands ,grid.5590.90000000122931605Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Beathe Haatveit
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway ,grid.5510.10000 0004 1936 8921Department of Psychology, University of Oslo, Oslo, Norway
| | - Catharina A. Hartman
- grid.4494.d0000 0000 9558 4598University of Groningen, University Medical Center Groningen, Interdisciplinary Center Psychopathology and Emotion Regulation, Groningen, The Netherlands
| | - Pieter J. Hoekstra
- grid.4494.d0000 0000 9558 4598University of Groningen, University Medical Center Groningen, Department of Child and Adolescent Psychiatry, Groningen, Netherlands
| | - Asta K. Håberg
- grid.5947.f0000 0001 1516 2393Department of Neuromedicine and Movement Science, NTNU – Norwegian University of Science and Technology, Trondheim, Norway ,grid.52522.320000 0004 0627 3560Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim, Norway
| | - Erik G. Jönsson
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway ,grid.4714.60000 0004 1937 0626Centre for Psychiatric Research, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Knut K. Kolskår
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway ,grid.5510.10000 0004 1936 8921Department of Psychology, University of Oslo, Oslo, Norway ,grid.416731.60000 0004 0612 1014Sunnaas Rehabilitation Hospital HT, Nesodden, Norway
| | - Stephanie Le Hellard
- grid.7914.b0000 0004 1936 7443NORMENT, KG Jebsen Centre for Psychosis Research, Department of Clinical Science, University of Bergen, Bergen, Norway ,grid.412008.f0000 0000 9753 1393Dr. Einar Martens Research Group for Biological Psychiatry, Department of Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Martina J. Lund
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Astri J. Lundervold
- grid.7914.b0000 0004 1936 7443Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
| | - Arvid Lundervold
- grid.7914.b0000 0004 1936 7443Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Ingrid Melle
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Jennifer Monereo Sánchez
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Linn C. Norbom
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway ,grid.5510.10000 0004 1936 8921Department of Psychology, University of Oslo, Oslo, Norway
| | - Jan E. Nordvik
- grid.416731.60000 0004 0612 1014Sunnaas Rehabilitation Hospital HT, Nesodden, Norway
| | - Lars Nyberg
- grid.12650.300000 0001 1034 3451Departments of Radiation Sciences and Integrative Medical Biology, Umeå Center for Functional Brain Imaging (UFB), Umeå University, Umeå, Sweden
| | - Jaap Oosterlaan
- Amsterdam UMC, University of Amsterdam & Vrije Universiteit Amsterdam, Emma Neuroscience Group at Emma Children’s Hospital, department of Pediatrics, Amsterdam Reproduction & Development, Amsterdam, The Netherlands
| | - Marco Papalino
- grid.7644.10000 0001 0120 3326Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari Aldo Moro, Bari, Italy
| | - Andreas Papassotiropoulos
- grid.6612.30000 0004 1937 0642Division of Molecular Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Life Sciences Training Facility, Department Biozentrum, University of Basel, Basel, Switzerland
| | - Giulio Pergola
- grid.7644.10000 0001 0120 3326Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari Aldo Moro, Bari, Italy
| | - Dominique J. F. de Quervain
- grid.6612.30000 0004 1937 0642Division of Cognitive Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
| | - Geneviève Richard
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway ,grid.5510.10000 0004 1936 8921Department of Psychology, University of Oslo, Oslo, Norway ,grid.416731.60000 0004 0612 1014Sunnaas Rehabilitation Hospital HT, Nesodden, Norway
| | - Anne-Marthe Sanders
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway ,grid.5510.10000 0004 1936 8921Department of Psychology, University of Oslo, Oslo, Norway ,grid.416731.60000 0004 0612 1014Sunnaas Rehabilitation Hospital HT, Nesodden, Norway
| | - Pierluigi Selvaggi
- grid.7644.10000 0001 0120 3326Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari Aldo Moro, Bari, Italy ,grid.13097.3c0000 0001 2322 6764Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | - Elena Shumskaya
- grid.10417.330000 0004 0444 9382Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands ,grid.5590.90000000122931605Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Vidar M. Steen
- grid.7914.b0000 0004 1936 7443NORMENT, KG Jebsen Centre for Psychosis Research, Department of Clinical Science, University of Bergen, Bergen, Norway ,grid.412008.f0000 0000 9753 1393Dr. Einar Martens Research Group for Biological Psychiatry, Department of Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Siren Tønnesen
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Kristine M. Ulrichsen
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway ,grid.5510.10000 0004 1936 8921Department of Psychology, University of Oslo, Oslo, Norway ,grid.416731.60000 0004 0612 1014Sunnaas Rehabilitation Hospital HT, Nesodden, Norway
| | - Marcel P. Zwiers
- grid.5590.90000000122931605Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Ole A. Andreassen
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Lars T. Westlye
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway ,grid.5510.10000 0004 1936 8921Department of Psychology, University of Oslo, Oslo, Norway
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14
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Quadri Z, Johnson N, Zamudio F, Miller A, Peters M, Smeltzer S, Hunt JB, Housley SB, Brown B, Kraner S, Norris CM, Nash K, Weeber E, Lee DC, Selenica MLB. Overexpression of human wtTDP-43 causes impairment in hippocampal plasticity and behavioral deficits in CAMKII-tTa transgenic mouse model. Mol Cell Neurosci 2019; 102:103418. [PMID: 31705957 DOI: 10.1016/j.mcn.2019.103418] [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: 05/07/2019] [Revised: 10/23/2019] [Accepted: 10/31/2019] [Indexed: 12/13/2022] Open
Abstract
AIMS The current study utilizes the adeno-associated viral gene transfer system in the CAMKIIα-tTA mouse model to overexpress human wild type TDP-43 (wtTDP-43) and α-synuclein (α-Syn) proteins. The co-existence of these proteins is evident in the pathology of neurodegenerative disorders such as frontotemporal lobar degeneration (FTLD), Parkinson disease (PD), and dementia with Lewy bodies (DLB). METHODS The novel bicistronic recombinant adeno-associated virus (rAAV) serotype 9 drives wtTDP-43 and α-Syn expression in the hippocampus via "TetO" CMV promoter. Behavior, electrophysiology, and biochemical and histological assays were used to validate neuropathology. RESULTS We report that overexpression of wtTDP-43 but not α-Syn contributes to hippocampal CA2-specific pyramidal neuronal loss and overall hippocampal atrophy. Further, we report a reduction of hippocampal long-term potentiation and decline in learning and memory performance of wtTDP-43 expressing mice. Elevated wtTDP-43 levels induced selective degeneration of Purkinje cell protein 4 (PCP-4) positive neurons while both wtTDP-43 and α-Syn expression reduced subsets of the glutamate receptor expression in the hippocampus. CONCLUSIONS Overall, our findings suggest the significant vulnerability of hippocampal neurons toward elevated wtTDP-43 levels possibly via PCP-4 and GluR-dependent calcium signaling pathways. Further, we report that wtTDP-43 expression induced selective CA2 subfield degeneration, contributing to the deterioration of the hippocampal-dependent cognitive phenotype.
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Affiliation(s)
- Zainuddin Quadri
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL, USA; Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, USA
| | - Nicholas Johnson
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL, USA; Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, USA
| | - Frank Zamudio
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL, USA; Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, USA
| | - Abraian Miller
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL, USA; Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, USA
| | - Melinda Peters
- Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, USA; Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Shayna Smeltzer
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL, USA; Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, USA
| | - Jerry B Hunt
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL, USA; Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, USA
| | - Steven B Housley
- Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, USA; Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Breanna Brown
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL, USA; Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, USA
| | - Susan Kraner
- Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Christopher M Norris
- Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Kevin Nash
- Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, USA; Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Edwin Weeber
- Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, USA; Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Daniel C Lee
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL, USA; Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, USA
| | - Maj-Linda B Selenica
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL, USA; Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, USA.
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15
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Mrdjen D, Fox EJ, Bukhari SA, Montine KS, Bendall SC, Montine TJ. The basis of cellular and regional vulnerability in Alzheimer's disease. Acta Neuropathol 2019; 138:729-749. [PMID: 31392412 PMCID: PMC6802290 DOI: 10.1007/s00401-019-02054-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 07/24/2019] [Accepted: 07/31/2019] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) differentially and specifically affects brain regions and neuronal cell types in a predictable pattern. Damage to the brain appears to spread and worsens with time, taking over more regions and activating multiple stressors that can converge to promote vulnerability of certain cell types. At the same time, other cell types and brain regions remain intact in the face of this onslaught of neuropathology. Although neuropathologic descriptions of AD have been extensively expanded and mapped over the last several decades, our understanding of the mechanisms underlying how certain regions and cell populations are specifically vulnerable or resistant has lagged behind. In this review, we detail what is known about the selectivity of local initiation of AD pathology in the hippocampus, its proposed spread via synaptic connections, and the diversity of clinical phenotypes and brain atrophy patterns that may arise from different fibrillar strains of pathologic proteins or genetic predispositions. We summarize accumulated and emerging knowledge of the cellular and molecular basis for neuroanatomic selectivity, consider potential disease-relevant differences between vulnerable and resistant neuronal cell types and isolate molecular markers to identify them.
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Affiliation(s)
- Dunja Mrdjen
- Department of Pathology, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Edward J Fox
- Department of Pathology, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Syed A Bukhari
- Department of Pathology, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Kathleen S Montine
- Department of Pathology, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Sean C Bendall
- Department of Pathology, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Thomas J Montine
- Department of Pathology, School of Medicine, Stanford University, Palo Alto, CA, USA.
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16
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Tiam1 is Critical for Glutamatergic Synapse Structure and Function in the Hippocampus. J Neurosci 2019; 39:9306-9315. [PMID: 31597723 DOI: 10.1523/jneurosci.1566-19.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 10/02/2019] [Accepted: 10/03/2019] [Indexed: 02/06/2023] Open
Abstract
Mounting evidence suggests numerous glutamatergic synapse subtypes exist in the brain, and that these subtypes are likely defined by unique molecular regulatory mechanisms. Recent work has identified substantial divergence of molecular composition between commonly studied Schaffer collateral synapses and perforant path-dentate gyrus (DG) synapses of the hippocampus. However, little is known about the molecular mechanisms that may confer unique properties to perforant path-DG synapses. Here we investigate whether the RhoGEF (Rho guanine-nucleotide exchange factor) protein Tiam1 plays a unique role in the regulation of glutamatergic synapses in dentate granule neurons using a combination of molecular, electrophysiological, and imaging approaches in rat entorhino-hippocampal slices of both sexes. We find that inhibition of Tiam1 function in dentate granule neurons reduces synaptic AMPA receptor function and causes dendritic spines to adopt an elongated filopodia-like morphology. We also find that Tiam1's support of perforant path-DG synapse function is dependent on its GEF domain and identify a potential role for the auto-inhibitory PH domain of Tiam1 in regulating Tiam1 function at these synapses. In marked contrast, reduced Tiam1 expression in CA1 pyramidal neurons produced no effect on glutamatergic synapse development. Together, these data identify a critical role for Tiam1 in the hippocampus and reveal a unique Tiam1-mediated molecular program of glutamatergic synapse regulation in dentate granule neurons.SIGNIFICANCE STATEMENT Several lines of evidence independently point to the molecular diversity of glutamatergic synapses in the brain. Rho guanine-nucleotide exchange factor (RhoGEF) proteins as powerful modulators of glutamatergic synapse function have also become increasingly appreciated in recent years. Here we investigate the synaptic regulatory role of the RhoGEF protein Tiam1, whose expression appears to be remarkably enriched in granule neurons of the dentate gyrus. We find that Tiam1 plays a critical role in the development of glutamatergic perforant path-dentate gyrus synapses, but not in commonly studied in Schaffer collateral-CA1 synapses. Together, these data reveal a unique RhoGEF-mediated molecular program of glutamatergic synapse regulation in dentate granule neurons.
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17
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Sarkar A, Mei A, Paquola ACM, Stern S, Bardy C, Klug JR, Kim S, Neshat N, Kim HJ, Ku M, Shokhirev MN, Adamowicz DH, Marchetto MC, Jappelli R, Erwin JA, Padmanabhan K, Shtrahman M, Jin X, Gage FH. Efficient Generation of CA3 Neurons from Human Pluripotent Stem Cells Enables Modeling of Hippocampal Connectivity In Vitro. Cell Stem Cell 2019; 22:684-697.e9. [PMID: 29727680 DOI: 10.1016/j.stem.2018.04.009] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 12/04/2017] [Accepted: 04/12/2018] [Indexed: 12/27/2022]
Abstract
Despite widespread interest in using human induced pluripotent stem cells (hiPSCs) in neurological disease modeling, a suitable model system to study human neuronal connectivity is lacking. Here, we report a comprehensive and efficient differentiation paradigm for hiPSCs that generate multiple CA3 pyramidal neuron subtypes as detected by single-cell RNA sequencing (RNA-seq). This differentiation paradigm exhibits characteristics of neuronal network maturation, and rabies virus tracing revealed synaptic connections between stem cell-derived dentate gyrus (DG) and CA3 neurons in vitro recapitulating the neuronal connectivity within the hippocampus. Because hippocampal dysfunction has been implicated in schizophrenia, we applied DG and CA3 differentiation paradigms to schizophrenia-patient-derived hiPSCs. We detected reduced activity in DG-CA3 co-culture and deficits in spontaneous and evoked activity in CA3 neurons from schizophrenia-patient-derived hiPSCs. Our approach offers critical insights into the network activity aspects of schizophrenia and may serve as a promising tool for modeling diseases with hippocampal vulnerability. VIDEO ABSTRACT.
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Affiliation(s)
- Anindita Sarkar
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Arianna Mei
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Apua C M Paquola
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; The Lieber Institute for Brain Development, Johns Hopkins School of Medicine, 855 N Wolfe Street, Baltimore, MD 21205, USA
| | - Shani Stern
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Cedric Bardy
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; Laboratory for Human Neurophysiology and Genetics, SAHMRI and College of Medicine and Public Health, Flinders University, Adelaide SA 5000, Australia
| | - Jason R Klug
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Stacy Kim
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Neda Neshat
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Hyung Joon Kim
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; Department of Psychiatry, Mary and Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198-5965, USA
| | - Manching Ku
- Next Generation Sequencing Core, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Maxim N Shokhirev
- Razavi Newman Integrative Genomics and Bioinformatics Core Facility, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - David H Adamowicz
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; Department of Neurosciences, UCSD School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Maria C Marchetto
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Roberto Jappelli
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jennifer A Erwin
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; The Lieber Institute for Brain Development, Johns Hopkins School of Medicine, 855 N Wolfe Street, Baltimore, MD 21205, USA
| | - Krishnan Padmanabhan
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; The Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Box 603, Rochester, NY 14642, USA
| | - Matthew Shtrahman
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; Department of Neurosciences, UCSD School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Xin Jin
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Fred H Gage
- Laboratory of Genetics, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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Tulke S, Haas CA, Häussler U. Expression of brain‐derived neurotrophic factor and structural plasticity in the dentate gyrus and
CA
2 region correlate with epileptiform activity. Epilepsia 2019; 60:1234-1247. [DOI: 10.1111/epi.15540] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 04/17/2019] [Accepted: 04/22/2019] [Indexed: 01/29/2023]
Affiliation(s)
- Susanne Tulke
- Experimental Epilepsy Research Department of Neurosurgery Medical Center - University of Freiburg Faculty of Medicine University of Freiburg Freiburg im Breisgau Germany
- Faculty of Biology University of Freiburg Freiburg im Breisgau Germany
| | - Carola A. Haas
- Experimental Epilepsy Research Department of Neurosurgery Medical Center - University of Freiburg Faculty of Medicine University of Freiburg Freiburg im Breisgau Germany
- BrainLinks‐BrainTools Cluster of Excellence University of Freiburg Freiburg im Breisgau Germany
| | - Ute Häussler
- Experimental Epilepsy Research Department of Neurosurgery Medical Center - University of Freiburg Faculty of Medicine University of Freiburg Freiburg im Breisgau Germany
- BrainLinks‐BrainTools Cluster of Excellence University of Freiburg Freiburg im Breisgau Germany
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19
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Helton TD, Zhao M, Farris S, Dudek SM. Diversity of dendritic morphology and entorhinal cortex synaptic effectiveness in mouse CA2 pyramidal neurons. Hippocampus 2018; 29:78-92. [PMID: 30067288 DOI: 10.1002/hipo.23012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 07/09/2018] [Accepted: 07/11/2018] [Indexed: 11/06/2022]
Abstract
Excitatory synaptic inputs from specific brain regions are often targeted to distinct dendritic arbors on hippocampal pyramidal neurons. Recent work has suggested that CA2 pyramidal neurons respond robustly and preferentially to excitatory input into the stratum lacunosum moleculare (SLM), with a relatively modest response to Schaffer collateral excitatory input into stratum radiatum (SR) in acute mouse hippocampal slices, but the extent to which this difference may be explained by morphology is unknown. In an effort to replicate these findings and to better understand the role of dendritic morphology in shaping responses from proximal and distal synaptic sites, we measured excitatory postsynaptic currents and action potentials in CA2 pyramidal cells in response to SR and SLM stimulation and subsequently analyzed confocal images of the filled cells. We found that, in contrast to previous reports, SR stimulation evoked substantial responses in all recorded CA2 pyramidal cells. Strikingly, however, we found that not all neurons responded to SLM stimulation, and in those neurons that did, responses evoked by SLM and SR were comparable in size and effectiveness in inducing action potentials. In a comprehensive morphometric analysis of CA2 pyramidal cell apical dendrites, we found that the neurons that were unresponsive to SLM stimulation were the same ones that lacked substantial apical dendritic arborization in the SLM. Neurons responsive to both SR and SLM stimulation had roughly equal amounts of dendritic branching in each layer. Remarkably, our study in mouse CA2 generally replicates the work characterizing the diversity of CA2 pyramidal cells in the guinea pig hippocampus. We conclude, then, that like in guinea pig, mouse CA2 pyramidal cells have a diverse apical dendrite morphology that is likely to be reflective of both the amount and source of excitatory input into CA2 from the entorhinal cortex and CA3.
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Affiliation(s)
- Thomas D Helton
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
| | - Meilan Zhao
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
| | - Shannon Farris
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
| | - Serena M Dudek
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
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20
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Singh Kushwaha S, Patro N, Kumar Patro I. A Sequential Study of Age-Related Lipofuscin Accumulation in Hippocampus and Striate Cortex of Rats. Ann Neurosci 2018; 25:223-233. [PMID: 31000961 DOI: 10.1159/000490908] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 06/14/2018] [Indexed: 12/12/2022] Open
Abstract
Background The age-pigment, lipofuscin that accumulates in cells intrinsically and progressively with age is considered as the hallmark of aging. This accumulation is more prominent in post-mitotic cells like neurons and also appears in glia. Purpose The aim of the present study was to assess the age-associated occurrence and distribution pattern of lipofuscin both in neurons and microglia in various regions of hippocampus and striate cortex. Methods The accumulation pattern of lipofuscin in hippocampus and striate cortex was observed in the female Wistar rats of 6 age groups, that is, 3, 6, 12, 18, 24, and 30 months using the autofluorescent property of lipofuscin and its specific localization in neurons and microglia by dual immunolabeling with NeuN and Iba-1 antibodies respectively. Cytoarchitectural and the morphological age-related changes were observed with cresyl violet staining. Results Lipofuscin pigments accumulate progressively through the normal aging process in hippocampus and striate cortex. However, in hippocampus, lipofuscin accumulates in a region-specific manner with the highest accumulation observed in cornu ammonis (CA) 1 and 3 subregions. Furthermore, the lipofuscin accumulation was also observed in microglia in the senile brains both in the hippocampus and striate cortex. Conclusion The progressive deposition of lipofuscin could result in cellular dysfunction. This encouraged us to forward the idea that microglia not only participate in the removal of the pigment from the neurons but also accumulate these waste products in itself. Such senescent microglia may contribute to age- related neurodegeneration as they lose the neuroprotective potential due to oxidative stress and thus may be unable to effectively phagocytose the age pigment.
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Affiliation(s)
- Sarika Singh Kushwaha
- School of Studies in Neuroscience, Jiwaji University, Gwalior, India.,School of Studies in Zoology, Jiwaji University, Gwalior, India
| | - Nisha Patro
- School of Studies in Neuroscience, Jiwaji University, Gwalior, India
| | - Ishan Kumar Patro
- School of Studies in Neuroscience, Jiwaji University, Gwalior, India.,School of Studies in Zoology, Jiwaji University, Gwalior, India
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21
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Li Y, Chen H, Jiang X, Li X, Lv J, Li M, Peng H, Tsien JZ, Liu T. Transcriptome Architecture of Adult Mouse Brain Revealed by Sparse Coding of Genome-Wide In Situ Hybridization Images. Neuroinformatics 2018; 15:285-295. [PMID: 28608010 DOI: 10.1007/s12021-017-9333-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Highly differentiated brain structures with distinctly different phenotypes are closely correlated with the unique combination of gene expression patterns. Using a genome-wide in situ hybridization image dataset released by Allen Mouse Brain Atlas, we present a data-driven method of dictionary learning and sparse coding. Our results show that sparse coding can elucidate patterns of transcriptome organization of mouse brain. A collection of components obtained from sparse coding display robust region-specific molecular signatures corresponding to the canonical neuroanatomical subdivisions including fiber tracts and ventricular systems. Other components revealed finer anatomical delineation of domains previously considered homogeneous. We also build an open-access informatics portal that contains the detail of each component along with its ontology and expressed genes. This portal allows intuitive visualization, interpretation and explorations of the transcriptome architecture of a mouse brain.
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Affiliation(s)
- Yujie Li
- Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA, USA
| | - Hanbo Chen
- Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA, USA
| | - Xi Jiang
- Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA, USA
| | - Xiang Li
- Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA, USA
| | - Jinglei Lv
- Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA, USA.,School of Automation, Northwestern Polytechnical University, Xi'an, China
| | - Meng Li
- Brain and Behavior Discovery Institute, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | | | - Joe Z Tsien
- Brain and Behavior Discovery Institute, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Tianming Liu
- Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA, USA.
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22
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Poli D, Wheeler BC, DeMarse TB, Brewer GJ. Pattern separation and completion of distinct axonal inputs transmitted via micro-tunnels between co-cultured hippocampal dentate, CA3, CA1 and entorhinal cortex networks. J Neural Eng 2018; 15:046009. [PMID: 29623900 DOI: 10.1088/1741-2552/aabc20] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Functions ascribed to the hippocampal sub-regions for encoding episodic memories include the separation of activity patterns propagated from the entorhinal cortex (EC) into the dentate gyrus (DG) and pattern completion in CA3 region. Since a direct assessment of these functions is lacking at the level of specific axonal inputs, our goal is to directly measure the separation and completion of distinct axonal inputs in engineered pairs of hippocampal sub-regional circuits. APPROACH We co-cultured EC-DG, DG-CA3, CA3-CA1 or CA1-EC neurons in a two-chamber PDMS device over a micro-electrode array (MEA60), inter-connected via distinct axons that grow through the micro-tunnels between the compartments. Taking advantage of the axonal accessibility, we quantified pattern separation and completion of the evoked activity transmitted through the tunnels from source into target well. Since pattern separation can be inferred when inputs are more correlated than outputs, we first compared the correlations among axonal inputs with those of target somata outputs. We then compared, in an analog approach, the distributions of correlation distances between rate patterns of the axonal inputs inside the tunnels with those of the somata outputs evoked in the target well. Finally, in a digital approach, we measured the spatial population distances between binary patterns of the same axonal inputs and somata outputs. MAIN RESULTS We found the strongest separation of the propagated axonal inputs when EC was axonally connected to DG, with a decline in separation to CA3 and to CA1 for both rate and digital approaches. Furthermore, the digital approach showed stronger pattern completion in CA3, then CA1 and EC. SIGNIFICANCE To the best of our knowledge, these are the first direct measures of pattern separation and completion for axonal transmission to the somata target outputs at the rate and digital population levels in each of four stages of the EC-DG-CA3-CA1 circuit.
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Affiliation(s)
- Daniele Poli
- Department of Biomedical Engineering, University of California, Irvine, CA, United States of America. Research Center 'Enrico Piaggio', University of Pisa, Pisa, Italy
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23
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Hippocampal area CA2: properties and contribution to hippocampal function. Cell Tissue Res 2018; 373:525-540. [PMID: 29335778 DOI: 10.1007/s00441-017-2769-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 12/07/2017] [Indexed: 12/30/2022]
Abstract
This review focuses on area CA2 of the hippocampus, as recent results have revealed the unique properties and surprising role of this region in encoding social, temporal and contextual aspects of memory. Originally identified and described by Lorente de No, in 1934, this region of the hippocampus has unique intra-and extra-hippocampal connectivity, sending and receiving input to septal and hypothalamic regions. Recent in vivo studies have indicated that CA2 pyramidal neurons encode spatial information during immobility and play an important role in the generation of sharp-wave ripples. Furthermore, CA2 neurons act to control overall excitability in the hippocampal network and have been found to be consistently altered in psychiatric diseases, indicating that normal function of this region is necessary for normal cognition. With its unique role, area CA2 has a unique molecular profile, interneuron density and composition. Furthermore, this region has an unusual manifestation of synaptic plasticity that does not occur post-synaptically at pyramidal neuron dendrities but through the local network of inhibitory neurons. While much progress has recently been made in understanding the large contribution of area CA2 to social memory formation, much still needs to be learned.
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24
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Linking major depression and the neural substrates of associative processing. COGNITIVE AFFECTIVE & BEHAVIORAL NEUROSCIENCE 2017; 16:1017-1026. [PMID: 27553369 DOI: 10.3758/s13415-016-0449-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
It has been proposed that mood correlates with the breadth of associative thinking. Here we set this hypothesis to the test in healthy and depressed individuals. Generating contextual associations engages a network of cortical regions including the parahippocampal cortex (PHC), retrosplenial complex, and medial prefrontal cortex. The link between mood, associative processing, and its underlying cortical infrastructure provides a promising avenue for elucidating the mechanisms underlying the cognitive impairments in major depressive disorder (MDD). The participants included 15 nonmedicated individuals with acute major depressive episodes and 15 healthy matched controls. In an fMRI experiment, participants viewed images of objects that were either strongly or weakly associated with a specific context (e.g., a beach chair vs. a water bottle) while rating the commonality of each object. Analyses were performed to examine the brain activation and structural differences between the groups. Consistent with our hypothesis, controls showed greater activation of the contextual associations network than did depressed participants. In addition, PHC structural volume was correlated with ruminative tendencies, and the volumes of the hippocampal subfields were significantly smaller in depressed participants. Surprisingly, depressed participants showed increased activity in the entorhinal cortex (ERC), as compared with controls. We integrated these findings within a mechanistic account linking mood and associative thinking and suggest directions for the future.
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25
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Cannabis-related hippocampal volumetric abnormalities specific to subregions in dependent users. Psychopharmacology (Berl) 2017; 234:2149-2157. [PMID: 28424833 DOI: 10.1007/s00213-017-4620-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 03/29/2017] [Indexed: 12/12/2022]
Abstract
RATIONALE Cannabis use is associated with neuroanatomical alterations in the hippocampus. While the hippocampus is composed of multiple subregions, their differential vulnerability to cannabis dependence remains unknown. OBJECTIVES The objective of the study is to investigate gray matter alteration in each of the hippocampal subregions (presubiculum, subiculum, cornu ammonis (CA) subfields CA1-4, and dentate gyrus (DG)) as associated with cannabis use and dependence. METHODS A total of 35 healthy controls (HC), 22 non-dependent (CB-nondep), and 39 dependent (CB-dep) cannabis users were recruited. We investigated group differences in hippocampal subregion volumes between HC, CB-nondep, and CB-dep users. We further explored the association between CB use variables (age of onset of regular use, monthly use, lifetime use) and hippocampal subregions in CB-nondep and CB-dep users separately. RESULTS The CA1, CA2/3, CA4/DG, as well as total hippocampal gray matter were reduced in volume in CB-dep but not in CB-nondep users, relative to HC. The right CA2/3 and CA4/DG volumes were also negatively associated with lifetime cannabis use in CB-dep users. CONCLUSIONS Our results suggest a regionally and dependence-specific influence of cannabis use on the hippocampus. Hippocampal alteration in cannabis users was specific to the CA and DG regions and confined to dependent users.
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26
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Smith AS, Williams Avram SK, Cymerblit-Sabba A, Song J, Young WS. Targeted activation of the hippocampal CA2 area strongly enhances social memory. Mol Psychiatry 2016; 21:1137-44. [PMID: 26728562 PMCID: PMC4935650 DOI: 10.1038/mp.2015.189] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/10/2015] [Accepted: 11/05/2015] [Indexed: 12/28/2022]
Abstract
Social cognition enables individuals to understand others' intentions. Social memory is a necessary component of this process, for without it, subsequent encounters are devoid of any historical information. The CA2 area of the hippocampus, particularly the vasopressin 1b receptor (Avpr1b) expressed there, is necessary for memory formation. We used optogenetics to excite vasopressin terminals, originating from the hypothalamic paraventricular nucleus, in the CA2 of mice. This markedly enhanced their social memory if the stimulation occurred during memory acquisition, but not retrieval. This effect was blocked by an Avpr1b antagonist. Finally, this enhanced memory is resistant to the social distraction of an introduced second mouse, important for socially navigating populations of individuals. Our results indicate the CA2 can increase the salience of social signals. Targeted pharmacotherapy with Avpr1b agonists or deep brain stimulation of the CA2 are potential avenues of treatment for those with declining social memory as in various dementias.
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Affiliation(s)
- Adam S. Smith
- Section on Neural Gene Expression, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Sarah K. Williams Avram
- Section on Neural Gene Expression, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Adi Cymerblit-Sabba
- Section on Neural Gene Expression, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - June Song
- Section on Neural Gene Expression, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - W. Scott Young
- Section on Neural Gene Expression, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
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27
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Bundy JL, Inouye BD, Mercer RS, Nowakowski RS. Fractionation-dependent improvements in proteome resolution in the mouse hippocampus by IEF LC-MS/MS. Electrophoresis 2016; 37:2054-62. [DOI: 10.1002/elps.201600076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 04/03/2016] [Accepted: 04/20/2016] [Indexed: 01/19/2023]
Affiliation(s)
- Joseph L. Bundy
- Department of Biomedical Sciences, College of Medicine; Florida State University; Tallahassee FL USA
| | - Brian D. Inouye
- Department of Biological Science; Florida State University; Tallahassee FL USA
| | - Roger S. Mercer
- Translational Science Laboratory; College of Medicine Florida State University; Tallahassee FL USA
| | - Richard S. Nowakowski
- Department of Biomedical Sciences, College of Medicine; Florida State University; Tallahassee FL USA
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28
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Abstract
Hippocampal area CA2 has several features that distinguish it from CA1 and CA3, including a unique gene expression profile, failure to display long-term potentiation and relative resistance to cell death. A recent increase in interest in the CA2 region, combined with the development of new methods to define and manipulate its neurons, has led to some exciting new discoveries on the properties of CA2 neurons and their role in behaviour. Here, we review these findings and call attention to the idea that the definition of area CA2 ought to be revised in light of gene expression data.
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29
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Cembrowski MS, Wang L, Sugino K, Shields BC, Spruston N. Hipposeq: a comprehensive RNA-seq database of gene expression in hippocampal principal neurons. eLife 2016; 5:e14997. [PMID: 27113915 PMCID: PMC4846374 DOI: 10.7554/elife.14997] [Citation(s) in RCA: 262] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 04/07/2016] [Indexed: 12/18/2022] Open
Abstract
Clarifying gene expression in narrowly defined neuronal populations can provide insight into cellular identity, computation, and functionality. Here, we used next-generation RNA sequencing (RNA-seq) to produce a quantitative, whole genome characterization of gene expression for the major excitatory neuronal classes of the hippocampus; namely, granule cells and mossy cells of the dentate gyrus, and pyramidal cells of areas CA3, CA2, and CA1. Moreover, for the canonical cell classes of the trisynaptic loop, we profiled transcriptomes at both dorsal and ventral poles, producing a cell-class- and region-specific transcriptional description for these populations. This dataset clarifies the transcriptional properties and identities of lesser-known cell classes, and moreover reveals unexpected variation in the trisynaptic loop across the dorsal-ventral axis. We have created a public resource, Hipposeq (http://hipposeq.janelia.org), which provides analysis and visualization of these data and will act as a roadmap relating molecules to cells, circuits, and computation in the hippocampus. DOI:http://dx.doi.org/10.7554/eLife.14997.001 Both mouse and human brains are made up of many millions of cells called neurons that are interconnected to form circuits. These neurons are not all the same, because different classes of neurons express different complements of genes. Neurons that express similar genes tend to look and act alike, whereas neurons that express different genes tend to be dissimilar. Cembrowski et al. have used a technique called next-generation RNA sequencing (RNA-seq) to determine which genes are expressed in groups of neurons that represent the main cell types found in a part of the brain called the hippocampus. This brain region is important for memory, and was chosen because the location and appearance of the main cell types in the hippocampus were already well understood. The approach revealed that the main types of neurons in the mouse hippocampus are all very different from each other in terms of gene expression, and that even neurons of the same type can exhibit large differences across the hippocampus. Cembrowski et al. created a website that will allow other researchers to easily navigate, analyze, and visualize gene expression data in these populations of neurons. Future work could next make use of recent technological advances to analyze gene expression in individual neurons, rather than groups of cells, to provide an even more detailed picture. It is also hoped that understanding the differences in gene expression will guide examination of how the hippocampus contributes to memory and what goes wrong in diseases that affect this region of the brain. DOI:http://dx.doi.org/10.7554/eLife.14997.002
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Affiliation(s)
- Mark S Cembrowski
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Lihua Wang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Ken Sugino
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Brenda C Shields
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Nelson Spruston
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
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Sosa M, Gillespie AK, Frank LM. Neural Activity Patterns Underlying Spatial Coding in the Hippocampus. Curr Top Behav Neurosci 2016; 37:43-100. [PMID: 27885550 DOI: 10.1007/7854_2016_462] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The hippocampus is well known as a central site for memory processing-critical for storing and later retrieving the experiences events of daily life so they can be used to shape future behavior. Much of what we know about the physiology underlying hippocampal function comes from spatial navigation studies in rodents, which have allowed great strides in understanding how the hippocampus represents experience at the cellular level. However, it remains a challenge to reconcile our knowledge of spatial encoding in the hippocampus with its demonstrated role in memory-dependent tasks in both humans and other animals. Moreover, our understanding of how networks of neurons coordinate their activity within and across hippocampal subregions to enable the encoding, consolidation, and retrieval of memories is incomplete. In this chapter, we explore how information may be represented at the cellular level and processed via coordinated patterns of activity throughout the subregions of the hippocampal network.
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Affiliation(s)
- Marielena Sosa
- Kavli Institute for Fundamental Neuroscience and Department of Physiology, University of California, San Francisco, USA
| | | | - Loren M Frank
- Kavli Institute for Fundamental Neuroscience and Department of Physiology, University of California, San Francisco, USA. .,Howard Hughes Medical Institute, Maryland, USA.
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Experience Modulates the Effects of Histone Deacetylase Inhibitors on Gene and Protein Expression in the Hippocampus: Impaired Plasticity in Aging. J Neurosci 2015; 35:11729-42. [PMID: 26290249 DOI: 10.1523/jneurosci.4339-14.2015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
UNLABELLED The therapeutic potential of histone deacetylase inhibitor (HDACi) treatment has attracted considerable attention in the emerging area of cognitive neuroepigenetics. The possibility that ongoing cognitive experience importantly regulates the cell biological effects of HDACi administration, however, has not been systematically examined. In an initial experiment addressing this issue, we tested whether water maze training influences the gene expression response to acute systemic HDACi administration in the young adult rat hippocampus. Training powerfully modulated the response to HDACi treatment, increasing the total number of genes regulated to nearly 3000, including many not typically linked to neural plasticity, compared with <300 following HDACi administration alone. Although water maze training itself also regulated nearly 1800 genes, the specific mRNAs, gene networks, and biological pathways involved were largely distinct when the same experience was provided together with HDACi administration. Next, we tested whether the synaptic protein response to HDACi treatment is similarly dependent on recent cognitive experience, and whether this plasticity is altered in aged rats with memory impairment. Whereas synaptic protein labeling in the young hippocampus was selectively increased when HDACi administration was provided in conjunction with water maze training, combined treatment had no effect on synaptic proteins in the aged hippocampus. Our findings indicate that ongoing experience potently regulates the molecular consequences of HDACi treatment and that the interaction of recent cognitive experience with histone acetylation dynamics is disrupted in the aged hippocampus. SIGNIFICANCE STATEMENT The possibility that interventions targeting epigenetic regulation could be effective in treating a range of neurodegenerative disorders has attracted considerable interest. Here we demonstrate in the rat hippocampus that ongoing experience powerfully modifies the molecular response to one such intervention, histone deacetylase inhibitor (HDACi) administration. A single learning episode dramatically shifts the gene expression profile induced by acute HDACi treatment, yielding a qualitatively distinct hippocampal transcriptome compared with the influence of behavioral training alone. The downstream synaptic protein response to HDACi administration is similarly experience-dependent, and we report that this plasticity is disrupted in the aged hippocampus. The findings highlight that accommodating the modulatory influence of ongoing experience represents a challenge for therapeutic development in the area of cognitive neuroepigenetics.
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Schmidt-Kastner R. Genomic approach to selective vulnerability of the hippocampus in brain ischemia–hypoxia. Neuroscience 2015; 309:259-79. [DOI: 10.1016/j.neuroscience.2015.08.034] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 08/12/2015] [Accepted: 08/17/2015] [Indexed: 01/06/2023]
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Postmortem examination of patient H.M.'s brain based on histological sectioning and digital 3D reconstruction. Nat Commun 2015; 5:3122. [PMID: 24473151 PMCID: PMC3916843 DOI: 10.1038/ncomms4122] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Accepted: 12/16/2013] [Indexed: 02/02/2023] Open
Abstract
Modern scientific knowledge of how memory functions are organized in the human brain originated from the case of Henry G. Molaison (H.M.), an epileptic patient whose amnesia ensued unexpectedly following a bilateral surgical ablation of medial temporal lobe structures, including the hippocampus. The neuroanatomical extent of the 1953 operation could not be assessed definitively during H.M.'s life. Here we describe the results of a procedure designed to reconstruct a microscopic anatomical model of the whole brain and conduct detailed 3D measurements in the medial temporal lobe region. This approach, combined with cellular-level imaging of stained histological slices, demonstrates a significant amount of residual hippocampal tissue with distinctive cytoarchitecture. Our study also reveals diffuse pathology in the deep white matter and a small, circumscribed lesion in the left orbitofrontal cortex. The findings constitute new evidence that may help elucidate the consequences of H.M.'s operation in the context of the brain's overall pathology.
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Mankin EA, Diehl GW, Sparks FT, Leutgeb S, Leutgeb JK. Hippocampal CA2 activity patterns change over time to a larger extent than between spatial contexts. Neuron 2015; 85:190-201. [PMID: 25569350 DOI: 10.1016/j.neuron.2014.12.001] [Citation(s) in RCA: 189] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2014] [Indexed: 11/24/2022]
Abstract
The hippocampal CA2 subregion has a different anatomical connectivity pattern within the entorhino-hippocampal circuit than either the CA1 or CA3 subregion. Yet major differences in the neuronal activity patterns of CA2 compared with the other CA subregions have not been reported. We show that standard spatial and temporal firing patterns of individual hippocampal principal neurons in behaving rats, such as place fields, theta modulation, and phase precession, are also present in CA2, but that the CA2 subregion differs substantially from the other CA subregions in its population coding. CA2 ensembles do not show a persistent code for space or for differences in context. Rather, CA2 activity patterns become progressively dissimilar over time periods of hours to days. The weak coding for a particular context is consistent with recent behavioral evidence that CA2 circuits preferentially support social, emotional, and temporal rather than spatial aspects of memory.
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Affiliation(s)
- Emily A Mankin
- Neurobiology Section and Center for Neural Circuits and Behavior, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Geoffrey W Diehl
- Neurobiology Section and Center for Neural Circuits and Behavior, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Fraser T Sparks
- Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Stefan Leutgeb
- Neurobiology Section and Center for Neural Circuits and Behavior, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jill K Leutgeb
- Neurobiology Section and Center for Neural Circuits and Behavior, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
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Mao LM, Xue B, Jin DZ, Wang JQ. Dynamic increases in AMPA receptor phosphorylation in the rat hippocampus in response to amphetamine. J Neurochem 2015; 133:795-805. [PMID: 25689263 DOI: 10.1111/jnc.13067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/30/2015] [Accepted: 02/04/2015] [Indexed: 01/12/2023]
Abstract
Increasing evidence supports the critical role of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptors in psychostimulant action. These receptors are regulated via a phosphorylation-dependent mechanism in their trafficking, distribution, and function. The hippocampus is a brain structure important for learning and memory and is emerging as a critical site for processing psychostimulant effects. To determine whether the hippocampal pool of AMPA receptors is regulated by stimulants, we investigated and characterized the impact of amphetamine (AMPH) on phosphorylation of AMPA receptors in the adult rat hippocampus in vivo. We found that AMPH markedly increased phosphorylation of AMPA receptor GluA1 subunits at serine 845 (S845) in the hippocampus. The effect of AMPH was dose dependent. A single dose of AMPH induced a rapid and transient increase in S845 phosphorylation. Among different hippocampal subfields, AMPH primarily elevated S845 phosphorylation in the Cornu Ammonis area 1 and dentate gyrus. In contrast to S845, serine 831 phosphorylation of GluA1 and serine 880 phosphorylation of GluA2 were not altered by AMPH. In addition, surface expression of hippocampal GluA1 was up-regulated, while the amount of intracellular GluA1 fraction was concurrently reduced in response to AMPH. GluA2 protein levels in either the surface or intracellular pool were insensitive to AMPH. These data demonstrate that the AMPA receptor in the hippocampus is sensitive to dopamine stimulation. Acute AMPH administration induces dose-, time-, site-, and subunit-dependent phosphorylation of AMPA receptors and facilitates surface trafficking of GluA1 AMPA receptors in hippocampal neurons in vivo. Acute injection of amphetamine increased phosphorylation of α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor GluA1 subunits at a protein kinase A (PKA)-sensitive site (S845) in the rat hippocampus. This increase was dose- and time-dependent and correlated with an increase in surface GluA1 expression. Thus, amphetamine can upregulate GluA1 phosphorylation and surface trafficking of GluA1 in hippocampal neurons in vivo.
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Affiliation(s)
- Li-Min Mao
- Department of Basic Medical Science, School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Bing Xue
- Department of Basic Medical Science, School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Dao-Zhong Jin
- Department of Basic Medical Science, School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - John Q Wang
- Department of Basic Medical Science, School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA.,Department of Anesthesiology, School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA.,Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
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San Antonio A, Liban K, Ikrar T, Tsyganovskiy E, Xu X. Distinct physiological and developmental properties of hippocampal CA2 subfield revealed by using anti-Purkinje cell protein 4 (PCP4) immunostaining. J Comp Neurol 2014; 522:1333-54. [PMID: 24166578 PMCID: PMC4001794 DOI: 10.1002/cne.23486] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 10/14/2013] [Accepted: 10/15/2013] [Indexed: 12/04/2022]
Abstract
The hippocampal CA2 subfield was initially identified by Lorente de Nó as an anatomically distinct region based on its cytoarchitectural features. Although there is an enormous body of literature on other hippocampal subfields (CA1 and CA3), relatively little is known about the physiological and developmental properties of CA2. Here we report identification of the CA2 region in the mouse by immunostaining with a Purkinje cell protein 4 (PCP4) antibody, which effectively delineates CA3/CA2 and CA2/CA1 borders and agrees well with previous cytoarchitectural definitions of CA2. The PCP4 immunostaining–delineated CA2 neurons have distinguishable differences in cell morphology, physiology, and synaptic circuit connections compared with distal CA3 and proximal CA1 regions. The average somatic sizes of excitatory cells differ across CA1–3, with the smallest to largest somatic size being CA1<CA2<CA3. CA2 excitatory cells have dense dendritic spines, but do not have thorny excrescences associated with bordering CA3 neurons. Photostimulation functional circuit mapping shows that CA2 excitatory neurons receives extensive synaptic input from CA3, but no detectable input from the dentate gyrus. CA2 excitatory cells also differ significantly from CA3 cells in intrinsic electrophysiological parameters, such as membrane capacitance and spiking rates. Although CA2 neurons differ from CA1 neurons for PCP4 and other marker expressions, these neurons have less distinct neurophysiological and morphological properties. Developmental examination revealed that PCP4 immunostaining first appears at postnatal day 4–5 and becomes successively more refined around CA2 until reaching adult form by postnatal day 21. J. Comp. Neurol. J. Comp. Neurol. 522:1333–1354, 2014. © 2013 Wiley Periodicals, Inc.
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Affiliation(s)
- Andrew San Antonio
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, California, 92697-1275
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Masser DR, Bixler GV, Brucklacher RM, Yan H, Giles CB, Wren JD, Sonntag WE, Freeman WM. Hippocampal subregions exhibit both distinct and shared transcriptomic responses to aging and nonneurodegenerative cognitive decline. J Gerontol A Biol Sci Med Sci 2014; 69:1311-24. [PMID: 24994846 DOI: 10.1093/gerona/glu091] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Impairment of hippocampal-dependent spatial learning and memory with aging affects a large segment of the aged population. Hippocampal subregions (CA1, CA3, and DG) have been previously reported to express both common and specific morphological, functional, and gene/protein alterations with aging and cognitive decline. To comprehensively assess gene expression with aging and cognitive decline, transcriptomic analysis of CA1, CA3, and DG was conducted using Adult (12M) and Aged (26M) F344xBN rats behaviorally characterized by Morris water maze performance. Each subregion demonstrated a specific pattern of responses with aging and with cognitive performance. The CA1 and CA3 demonstrating the greatest degree of shared gene expression changes. Analysis of the pathways, processes, and regulators of these transcriptomic changes also exhibit a similar pattern of commonalities and differences across subregions. Gene expression changes between Aged cognitively Intact and Aged cognitively Impaired rats often showed an inversion of the changes between Adult and Aged rats. This failure to adapt rather than an exacerbation of the aging phenotype questions a conventional view that cognitive decline is exaggerated aging. These results are a resource for investigators studying cognitive decline and also demonstrate the need to individually examine hippocampal subregions in molecular analyses of aging and cognitive decline.
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Affiliation(s)
- Dustin R Masser
- Department of Physiology and Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center
| | - Georgina V Bixler
- Genome Sciences Facility, Penn State College of Medicine, Hershey, Pennsylvania
| | | | - Han Yan
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center
| | - Cory B Giles
- Arthritis & Clinical Immunology Program, Oklahoma Medicine Research Foundation
| | - Jonathan D Wren
- Arthritis & Clinical Immunology Program, Oklahoma Medicine Research Foundation
| | - William E Sonntag
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center
| | - Willard M Freeman
- Department of Physiology and Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center.
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Gordon BA, Blazey T, Benzinger TLS, Head D. Effects of aging and Alzheimer's disease along the longitudinal axis of the hippocampus. J Alzheimers Dis 2014; 37:41-50. [PMID: 23780659 DOI: 10.3233/jad-130011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The hippocampus is often treated as a uniform structure, but possesses differential projections to surrounding cortex along its longitudinal axis. This heterogeneity could create varied susceptibility to pathological influences, potentially leading to non-uniform volumetric associations with advancing age and Alzheimer's disease (AD). Previous examinations of aging and AD effects on hippocampal subdivisions have produced highly discrepant findings. To clarify these inconsistencies, we examined the hippocampal head, body, and tail in a large sample of 292 cognitively normal, 37 very mildly demented, and 18 mildly demented individuals, divided into two independent samples. As often done in the literature, we characterized qualitative patterns across these regions, but extended these results by explicitly testing for quantitative differences. In each sample of cognitively normal individuals, the head and body demonstrated greater age effects than the tail. In each sample contrasting AD and cognitively normal individuals, all three regions showed significant volume reductions, with the greatest effect on the head. When examining increasing severity of dementia, the hippocampal head showed progressive volume loss, while the body and tail did not. The patterns of results examining both aging and AD were relatively consistent across the independent samples. These results indicate that there is an anterior-to-posterior gradient of loss within the hippocampus with both advancing age and AD.
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Affiliation(s)
- Brian A Gordon
- Department of Psychology, Washington University in St. Louis, St. Louis, MO 63130-4899, USA.
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Brewer GJ, Boehler MD, Leondopulos S, Pan L, Alagapan S, DeMarse TB, Wheeler BC. Toward a self-wired active reconstruction of the hippocampal trisynaptic loop: DG-CA3. Front Neural Circuits 2013; 7:165. [PMID: 24155693 PMCID: PMC3800815 DOI: 10.3389/fncir.2013.00165] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 09/23/2013] [Indexed: 01/08/2023] Open
Abstract
The mammalian hippocampus functions to encode and retrieve memories by transiently changing synaptic strengths, yet encoding in individual subregions for transmission between regions remains poorly understood. Toward the goal of better understanding the coding in the trisynaptic pathway from the dentate gyrus (DG) to the CA3 and CA1, we report a novel microfabricated device that divides a micro-electrode array into two compartments of separate hippocampal network subregions connected by axons that grow through 3 × 10 × 400 μm tunnels. Gene expression by qPCR demonstrated selective enrichment of separate DG, CA3, and CA1 subregions. Reconnection of DG to CA3 altered burst dynamics associated with marked enrichment of GAD67 in DG and GFAP in CA3. Surprisingly, DG axon spike propagation was preferentially unidirectional to the CA3 region at 0.5 m/s with little reverse transmission. Therefore, select hippocampal subregions intrinsically self-wire in anatomically appropriate patterns and maintain their distinct subregion phenotype without external inputs.
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Affiliation(s)
- Gregory J Brewer
- Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine Springfield, IL, USA ; Department of Neurology, Southern Illinois University School of Medicine Springfield, IL, USA
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Cui Z, Gerfen CR, Young WS. Hypothalamic and other connections with dorsal CA2 area of the mouse hippocampus. J Comp Neurol 2013; 521:1844-66. [PMID: 23172108 DOI: 10.1002/cne.23263] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 06/22/2012] [Accepted: 11/06/2012] [Indexed: 11/08/2022]
Abstract
The CA2 area is an important, although relatively unexplored, component of the hippocampus. We used various tracers to provide a comprehensive analysis of CA2 connections in C57BL/6J mice. Using various adeno-associated viruses that express fluorescent proteins, we found a vasopressinergic projection from the paraventricular nuclei of the hypothalamus (PVN) to the CA2 as well as a projection from pyramidal neurons of the CA2 to the supramammillary nuclei. These projections were confirmed by retrograde tracing. As expected, we observed CA2 afferent projections from neurons in ipsilateral entorhinal cortical layer II as well as from bilateral dorsal CA2 and CA3 using retrograde tracers. Additionally, we saw CA2 neuronal input from bilateral medial septal nuclei, vertical and horizontal limbs of the nucleus of diagonal band of Broca, supramammillary nuclei (SUM), and median raphe nucleus. Dorsal CA2 injections of adeno-associated virus expressing green fluorescent protein revealed axonal projections primarily to dorsal CA1, CA2, and CA3 bilaterally. No projection was detected to the entorhinal cortex from the dorsal CA2. These results are consistent with recent observations that the dorsal CA2 forms disynaptic connections with the entorhinal cortex to influence dynamic memory processing. Mouse dorsal CA2 neurons send bilateral projections to the medial and lateral septal nuclei, vertical and horizontal limbs of the diagonal band of Broca, and SUM. Novel connections from the PVN and to the SUM suggest important regulatory roles for CA2 in mediating social and emotional input for memory processing.
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Affiliation(s)
- Zhenzhong Cui
- Section on Neural Gene Expression, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892, USA
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41
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Kou ZZ, Qu J, Zhang DL, Li H, Li YQ. Noise-induced hearing loss is correlated with alterations in the expression of GABAB receptors and PKC gamma in the murine cochlear nucleus complex. Front Neuroanat 2013; 7:25. [PMID: 23908607 PMCID: PMC3726868 DOI: 10.3389/fnana.2013.00025] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Accepted: 07/11/2013] [Indexed: 01/08/2023] Open
Abstract
Noise overexposure may induce permanent noise-induced hearing loss (NIHL). The cochlear nucleus complex (CNC) is the entry point for sensory information in the central auditory system. Impairments in gamma-aminobutyric acid (GABA)—mediated synaptic transmission in the CNC have been implicated in the pathogenesis of auditory disorders. However, the role of protein kinase C (PKC) signaling pathway in GABAergic inhibition in the CNC in NIHL remains elusive. Thus, we investigated the alterations of glutamic acid decarboxylase 67 (GAD67, the chemical marker for GABA-containing neurons), PKC γ subunit (PKCγ) and GABAB receptor (GABABR) expression in the CNC using transgenic GAD67-green fluorescent protein (GFP) knock-in mice, BALB/c mice and C57 mice. Immunohistochemical results indicate that the GFP-labeled GABAergic neurons were distributed in the molecular layer (ML) and fusiform cell layer (FCL) of the dorsal cochlear nucleus (DCN). We found that 69.91% of the GFP-positive neurons in the DCN were immunopositive for both PKCγ and GABABR1. The GAD67-positive terminals made contacts with PKCγ/GABABR1 colocalized neurons. Then we measured the changes of auditory thresholds in mice after noise exposure for 2 weeks, and detected the GAD67, PKCγ, and GABABR expression at mRNA and protein levels in the CNC. With noise over-exposure, there was a reduction in GABABR accompanied by an increase in PKCγ expression, but no significant change in GAD67 expression. In summary, our results demonstrate that alterations in the expression of PKCγ and GABABRs may be involved in impairments in GABAergic inhibition within the CNC and the development of NIHL.
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Affiliation(s)
- Zhen-Zhen Kou
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
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Daulatzai MA. Neurotoxic Saboteurs: Straws that Break the Hippo’s (Hippocampus) Back Drive Cognitive Impairment and Alzheimer’s Disease. Neurotox Res 2013; 24:407-59. [DOI: 10.1007/s12640-013-9407-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 06/06/2013] [Accepted: 06/17/2013] [Indexed: 12/29/2022]
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Laeremans A, Nys J, Luyten W, D'Hooge R, Paulussen M, Arckens L. AMIGO2 mRNA expression in hippocampal CA2 and CA3a. Brain Struct Funct 2013; 218:123-30. [PMID: 22314660 DOI: 10.1007/s00429-012-0387-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Accepted: 01/17/2012] [Indexed: 10/14/2022]
Abstract
AMIGO2, or amphoterin-induced gene and ORF (open reading frame) 2, belongs to the leucine-rich repeats and immunoglobulin superfamilies. The protein is a downstream target of calcium-dependent survival signals and, therefore, promotes neuronal survival. Here, we describe the mRNA distribution pattern of AMIGO2 throughout the mouse brain with special emphasis on the hippocampus. In the Ammon's horn, a detailed comparison between the subregional mRNA expression patterns of AMIGO2 and Pcp4 (Purkinje cell protein 4)--a known molecular marker of hippocampal CA2 (Cornu Ammonis 2)--revealed a prominent AMIGO2 mRNA expression level in both the CA2 and the CA3a (Cornu Ammonis 3a) subregion of the dorsal and ventral hippocampus. Since this CA2/CA3a region is particularly resistant to neuronal injury and neurotoxicity [Stanfield and Cowan (Brain Res 309(2):299–307 1984); Sloviter (J Comp Neurol 280(2):183–196 1989); Leranth and Ribak (Exp Brain Res 85(1):129–136 1991); Young and Dragunow (Exp Neurol 133(2):125–137 1995); Ochiishi et al. (Neurosci 93(3):955–967 1999)], we suggest that the expression pattern of AMIGO2 indeed fits with its involvement in neuroprotection.
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Affiliation(s)
- Annelies Laeremans
- Laboratory of Neuroplasticity and Neuroproteomics, University of Leuven, Naamsestraat 59, Box 2467, 3000 Leuven, Belgium
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VanGuilder Starkey HD, Sonntag WE, Freeman WM. Increased hippocampal NgR1 signaling machinery in aged rats with deficits of spatial cognition. Eur J Neurosci 2013; 37:1643-58. [PMID: 23438185 DOI: 10.1111/ejn.12165] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 01/18/2013] [Accepted: 01/21/2013] [Indexed: 01/31/2023]
Abstract
Myelin-associated inhibitor/NgR1 signaling has important roles in modulation of synaptic plasticity, with demonstrated effects on cognitive function. We have previously demonstrated that NgR1 and its ligands are upregulated in the hippocampus of aged rats with impaired spatial learning and memory, but it is unknown whether increased expression of these proteins indicates a potential increase in pathway signaling because NgR1 requires co-receptors for signal transduction through RhoA. Two co-receptor complexes have been identified to date, comprised of NgR1 and LINGO-1, and either p75 or TROY. In this study, we assessed the expression of LINGO-1, p75 and TROY, and the downstream effector RhoA in mature adult (12 months) and aged (26 months) male Fischer 344/Brown Norway hybrid rats classified as cognitively impaired or cognitively intact by Morris water maze testing. The hippocampal distribution of NgR1 and its co-receptors was assessed to determine whether receptor/co-receptor interaction, and therefore signaling through this pathway, is possible. Protein expression of LINGO-1, p75, TROY and RhoA was significantly elevated in cognitively impaired, but not intact, aged rats compared with mature adults, and expression levels correlated significantly with water maze performance. Co-localization of NgR1 with LINGO-1, p75 and TROY was observed in hippocampal neurons of aged, cognitively impaired rats. Further, expression profiles of NgR1 pathway components were demonstrated to classify rats as cognitively intact or cognitively impaired with high accuracy. Together, this suggests that hippocampal induction of this pathway is a conserved phenomenon in cognitive decline that may impair learning and memory by suppressing neuronal plasticity.
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Affiliation(s)
- Heather D VanGuilder Starkey
- Department of Pharmacology, R130 Hershey Center for Applied Research, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA
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Koike M, Shibata M, Ezaki J, Peters C, Saftig P, Kominami E, Uchiyama Y. Differences in expression patterns of cathepsin C/dipeptidyl peptidase I in normal, pathological and aged mouse central nervous system. Eur J Neurosci 2012; 37:816-30. [PMID: 23279039 DOI: 10.1111/ejn.12096] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 11/05/2012] [Accepted: 11/16/2012] [Indexed: 12/18/2022]
Abstract
Cathepsin C (CC) (EC 3.4.14.1, dipeptidyl peptidase I) is a lysosomal cysteine protease that is required for the activation of several granule-associated serine proteases in vivo. CC has been shown to be constitutively expressed in various tissues, but the enzyme is hardly detectable in central nervous system (CNS) tissues. In the present study, we investigated the regional and cellular distribution of CC in normal, aging and pathological mouse brains. Immunoblotting failed to detect CC protein in whole brain tissues of normal mice, as previously described. However, low proteolytic activity of CC was detected in a brain region-dependent manner, and granular immunohistochemical signals were found in neuronal perikarya of particular brain regions, including the accessory olfactory bulb, the septum, CA2 of the hippocampus, a part of the cerebral cortex, the medial geniculate, and the inferior colliculus. In aged mice, the number of CC-positive neurons increased to some extent. The protein level of CC and its proteolytic activity showed significant increases in particular brain regions of mouse models with pathological conditions--the thalamus in cathepsin D-deficient mice, the hippocampus of ipsilateral brain hemispheres after hypoxic-ischemic brain injury, and peri-damaged portions of brains after penetrating injury. In such pathological conditions, the majority of the cells that were strongly immunopositive for CC were activated microglia. These lines of evidence suggest that CC is involved in normal neuronal function in certain brain regions, and also participates in inflammatory processes accompanying pathogenesis in the CNS.
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Affiliation(s)
- Masato Koike
- Department of Cell Biology and Neuroscience, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
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Evans SJ, Watson SJ, Akil H. Evaluation of sensitivity, performance and reproducibility of microarray technology in neuronal tissue. Integr Comp Biol 2012; 43:780-5. [PMID: 21680476 DOI: 10.1093/icb/43.6.780] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Microarray technology is a powerful technique that allows the simultaneous study of thousands of gene transcripts. During the past two years there has been an explosion of publications describing experiments utilizing microarray technology that range from original research findings from biological paradigms to mathematically modeled systems. However, neuroscientists using microarray technology face significant challenges due to high tissue complexity, low abundance transcripts, and small magnitude changes in transcript levels that have significant biological impact. This manuscript describes a series of studies designed to address issues regarding microarray sensitivity, ability of microarrays to detect subtle changes, and reproducibility of microarray experiments, all in the context of neuronal tissue. From the presentation of these studies, the authors argue that although microarray technology is limited with regards to sensitivity, the outcome of these experiments, if approached with appropriate skepticism, can be fruitful in the generation of hypotheses and seeding of future experiments.
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Affiliation(s)
- S J Evans
- Mental Health Research Institute, University of Michigan, Ann Arbor, Michigan 48109
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Caruana DA, Alexander GM, Dudek SM. New insights into the regulation of synaptic plasticity from an unexpected place: hippocampal area CA2. Learn Mem 2012; 19:391-400. [PMID: 22904370 DOI: 10.1101/lm.025304.111] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The search for molecules that restrict synaptic plasticity in the brain has focused primarily on sensory systems during early postnatal development, as critical periods for inducing plasticity in sensory regions are easily defined. The recent discovery that Schaffer collateral inputs to hippocampal area CA2 do not readily support canonical activity-dependent long-term potentiation (LTP) serves as a reminder that the capacity for synaptic modification is also regulated anatomically across different brain regions. Hippocampal CA2 shares features with other similarly "LTP-resistant" brain areas in that many of the genes linked to synaptic function and the associated proteins known to restrict synaptic plasticity are expressed there. Add to this a rich complement of receptors and signaling molecules permissive for induction of atypical forms of synaptic potentiation, and area CA2 becomes an ideal model system for studying specific modulators of brain plasticity. Additionally, recent evidence suggests that hippocampal CA2 is instrumental for certain forms of learning, memory, and social behavior, but the links between CA2-enriched molecules and putative CA2-dependent behaviors are only just beginning to be made. In this review, we offer a detailed look at what is currently known about the synaptic plasticity in this important, yet largely overlooked component of the hippocampus and consider how the study of CA2 may provide clues to understanding the molecular signals critical to the modulation of synaptic function in different brain regions and across different stages of development.
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Affiliation(s)
- Douglas A Caruana
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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Götz J, Matamales M, Götz NN, Ittner LM, Eckert A. Alzheimer's disease models and functional genomics-How many needles are there in the haystack? Front Physiol 2012; 3:320. [PMID: 22934069 PMCID: PMC3429089 DOI: 10.3389/fphys.2012.00320] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 07/23/2012] [Indexed: 11/25/2022] Open
Abstract
Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD) are complex human brain disorders that affect an increasing number of people worldwide. With the identification first of the proteins that aggregate in AD and FTLD brains and subsequently of pathogenic gene mutations that cause their formation in the familial cases, the foundation was laid for the generation of animal models. These recapitulate essential aspects of the human conditions; expression of mutant forms of the amyloid-β protein-encoding APP gene in mice reproduces amyloid-β (Aβ) plaque formation in AD, while that of mutant forms of the tau-encoding microtubule-associated protein tau (MAPT) gene reproduces tau-containing neurofibrillary tangle formation, a lesion that is also prevalent in FTLD-Tau. The mouse models have been complemented by those in lower species such as C. elegans or Drosophila, highlighting the crucial role for Aβ and tau in human neurodegenerative disease. In this review, we will introduce selected AD/FTLD models and discuss how they were instrumental, by identifying deregulated mRNAs, miRNAs and proteins, in dissecting pathogenic mechanisms in neurodegenerative disease. We will discuss some recent examples, which includes miRNA species that are specifically deregulated by Aβ, mitochondrial proteins that are targets of both Aβ and tau, and the nuclear splicing factor SFPQ that accumulates in the cytoplasm in a tau-dependent manner. These examples illustrate how a functional genomics approach followed by a careful validation in experimental models and human tissue leads to a deeper understanding of the pathogenesis of AD and FTLD and ultimately, may help in finding a cure.
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Affiliation(s)
- Jürgen Götz
- Centre for Ageing Dementia Research, Queensland Brain Institute, The University of QueenslandSt Lucia, QLD, Australia
| | - Miriam Matamales
- Centre for Ageing Dementia Research, Queensland Brain Institute, The University of QueenslandSt Lucia, QLD, Australia
| | - Naeman N. Götz
- Centre for Ageing Dementia Research, Queensland Brain Institute, The University of QueenslandSt Lucia, QLD, Australia
| | - Lars M. Ittner
- Alzheimer's and Parkinson's Disease Laboratory, Brain and Mind Research Institute, University of SydneyCamperdown, NSW, Australia
| | - Anne Eckert
- Neurobiology Laboratory, Psychiatric University Clinics Basel, University of BaselBasel, Switzerland
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Morrens J, Van Den Broeck W, Kempermann G. Glial cells in adult neurogenesis. Glia 2011; 60:159-74. [PMID: 22076934 DOI: 10.1002/glia.21247] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 08/30/2011] [Indexed: 01/17/2023]
Abstract
Adult neurogenesis is an exceptional feature of the adult brain and in an intriguing way bridges between neuronal and glial neurobiology. Essentially, all classes of glial cells are directly or indirectly linked to this process. Cells with astrocytic features, for example, serve as radial glia-like stem cells in the two neurogenic regions of the adult brain, the hippocampal dentate gyrus and the subventricular zone of the lateral ventricles, producing new neurons, create a microenvironment permissive for neurogenesis, and are themselves generated alongside the new neurons in an associated but independently regulated process. Oligodendrocytes are generated from precursor cells intermingled with those generating neurons in an independent lineage. NG2 cells have certain precursor cell properties and are found throughout the brain parenchyma. They respond to extrinsic stimuli and injury but do not generate neurons even though they can express some preneuronal markers. Microglia have positive and negative regulatory effects as constituents of the "neurogenic niche". Ependymal cells play incompletely understood roles in adult neurogenesis, but under certain conditions might exert (back-up) precursor cell functions. Glial contributions to adult neurogenesis can be direct or indirect and are mediated by mechanisms ranging from gap-junctional to paracrine and endocrine. As the two neurogenic regions differ between each other and both from the non-neurogenic rest of the brain, the question arises in how far regionalization of both the glia-like precursor cells as well as of the glial cells determines site-specific "neurogenic permissiveness." In any case, however, "neurogenesis" appears to be an essentially glial achievement.
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Affiliation(s)
- Joachim Morrens
- Department of Morphology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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A pathophysiological framework of hippocampal dysfunction in ageing and disease. Nat Rev Neurosci 2011; 12:585-601. [PMID: 21897434 DOI: 10.1038/nrn3085] [Citation(s) in RCA: 673] [Impact Index Per Article: 51.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The hippocampal formation has been implicated in a growing number of disorders, from Alzheimer's disease and cognitive ageing to schizophrenia and depression. How can the hippocampal formation, a complex circuit that spans the temporal lobes, be involved in a range of such phenotypically diverse and mechanistically distinct disorders? Recent neuroimaging findings indicate that these disorders differentially target distinct subregions of the hippocampal circuit. In addition, some disorders are associated with hippocampal hypometabolism, whereas others show evidence of hypermetabolism. Interpreted in the context of the functional and molecular organization of the hippocampal circuit, these observations give rise to a unified pathophysiological framework of hippocampal dysfunction.
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