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Caldwell HK, Aulino EA, Rodriguez KM, Witchey SK, Yaw AM. Social Context, Stress, Neuropsychiatric Disorders, and the Vasopressin 1b Receptor. Front Neurosci 2017; 11:567. [PMID: 29085277 PMCID: PMC5650633 DOI: 10.3389/fnins.2017.00567] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 09/27/2017] [Indexed: 01/28/2023] Open
Abstract
The arginine vasopressin 1b receptor (Avpr1b) is involved in the modulation of a variety of behaviors and is an important part of the mammalian hormonal stress axis. The Avpr1b is prominent in hippocampal CA2 pyramidal cells and in the anterior pituitary corticotrophs. Decades of research on this receptor has demonstrated its importance to the modulation of social recognition memory, social forms of aggression, and modulation of the hypothalamic-pituitary-adrenal axis, particularly under conditions of acute stress. Further, work in humans suggests that the Avpr1b may play a role in human neuropsychiatric disorders and its modulation may have therapeutic potential. This paper reviews what is known about the role of the Avpr1b in the context of social behaviors, the stress axis, and human neuropsychiatric disorders. Further, possible mechanisms for how Avpr1b activation within the hippocampus vs. Avpr1b activation within anterior pituitary may interact with one another to affect behavioral output are proposed.
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Affiliation(s)
- Heather K Caldwell
- Laboratory of Neuroendocrinology and Behavior, Department of Biological Sciences Kent State University, Kent, OH, United States.,School of Biomedical Sciences, Kent State University, Kent, OH, United States
| | - Elizabeth A Aulino
- Laboratory of Neuroendocrinology and Behavior, Department of Biological Sciences Kent State University, Kent, OH, United States
| | - Karla M Rodriguez
- School of Biomedical Sciences, Kent State University, Kent, OH, United States
| | - Shannah K Witchey
- Laboratory of Neuroendocrinology and Behavior, Department of Biological Sciences Kent State University, Kent, OH, United States
| | - Alexandra M Yaw
- School of Biomedical Sciences, Kent State University, Kent, OH, United States
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52
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Sun Q, Sotayo A, Cazzulino AS, Snyder AM, Denny CA, Siegelbaum SA. Proximodistal Heterogeneity of Hippocampal CA3 Pyramidal Neuron Intrinsic Properties, Connectivity, and Reactivation during Memory Recall. Neuron 2017; 95:656-672.e3. [PMID: 28772124 DOI: 10.1016/j.neuron.2017.07.012] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 05/25/2017] [Accepted: 07/12/2017] [Indexed: 12/21/2022]
Abstract
The hippocampal CA3 region is classically viewed as a homogeneous autoassociative network critical for associative memory and pattern completion. However, recent evidence has demonstrated a striking heterogeneity along the transverse, or proximodistal, axis of CA3 in spatial encoding and memory. Here we report the presence of striking proximodistal gradients in intrinsic membrane properties and synaptic connectivity for dorsal CA3. A decreasing gradient of mossy fiber synaptic strength along the proximodistal axis is mirrored by an increasing gradient of direct synaptic excitation from entorhinal cortex. Furthermore, we uncovered a nonuniform pattern of reactivation of fear memory traces, with the most robust reactivation during memory retrieval occurring in mid-CA3 (CA3b), the region showing the strongest net recurrent excitation. Our results suggest that heterogeneity in both intrinsic properties and synaptic connectivity may contribute to the distinct spatial encoding and behavioral role of CA3 subregions along the proximodistal axis.
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Affiliation(s)
- Qian Sun
- Department of Neuroscience, Columbia University, New York, NY 10032, USA.
| | - Alaba Sotayo
- Department of Neuroscience, Columbia University, New York, NY 10032, USA
| | - Alejandro S Cazzulino
- Department of Psychiatry, Columbia University, New York, NY 10032, USA; Division of Integrative Neuroscience, New York State Psychiatric Institute (NYSPI)/Research Foundation for Mental Hygiene, Inc. (RFMH), New York, NY 10032, USA
| | - Anna M Snyder
- Department of Neuroscience, Columbia University, New York, NY 10032, USA
| | - Christine A Denny
- Department of Psychiatry, Columbia University, New York, NY 10032, USA; Division of Integrative Neuroscience, New York State Psychiatric Institute (NYSPI)/Research Foundation for Mental Hygiene, Inc. (RFMH), New York, NY 10032, USA
| | - Steven A Siegelbaum
- Department of Neuroscience, Columbia University, New York, NY 10032, USA; Department of Pharmacology, Columbia University, New York, NY 10032, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10032, USA.
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53
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Heterogeneity in Kv2 Channel Expression Shapes Action Potential Characteristics and Firing Patterns in CA1 versus CA2 Hippocampal Pyramidal Neurons. eNeuro 2017; 4:eN-NWR-0267-17. [PMID: 28856240 PMCID: PMC5569380 DOI: 10.1523/eneuro.0267-17.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 08/03/2017] [Accepted: 08/09/2017] [Indexed: 01/07/2023] Open
Abstract
The CA1 region of the hippocampus plays a critical role in spatial and contextual memory, and has well-established circuitry, function and plasticity. In contrast, the properties of the flanking CA2 pyramidal neurons (PNs), important for social memory, and lacking CA1-like plasticity, remain relatively understudied. In particular, little is known regarding the expression of voltage-gated K+ (Kv) channels and the contribution of these channels to the distinct properties of intrinsic excitability, action potential (AP) waveform, firing patterns and neurotransmission between CA1 and CA2 PNs. In the present study, we used multiplex fluorescence immunolabeling of mouse brain sections, and whole-cell recordings in acute mouse brain slices, to define the role of heterogeneous expression of Kv2 family Kv channels in CA1 versus CA2 pyramidal cell excitability. Our results show that the somatodendritic delayed rectifier Kv channel subunits Kv2.1, Kv2.2, and their auxiliary subunit AMIGO-1 have region-specific differences in expression in PNs, with the highest expression levels in CA1, a sharp decrease at the CA1-CA2 boundary, and significantly reduced levels in CA2 neurons. PNs in CA1 exhibit a robust contribution of Guangxitoxin-1E-sensitive Kv2-based delayed rectifier current to AP shape and after-hyperpolarization potential (AHP) relative to that seen in CA2 PNs. Our results indicate that robust Kv2 channel expression confers a distinct pattern of intrinsic excitability to CA1 PNs, potentially contributing to their different roles in hippocampal network function.
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54
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Hamilton DJ, White CM, Rees CL, Wheeler DW, Ascoli GA. Molecular fingerprinting of principal neurons in the rodent hippocampus: A neuroinformatics approach. J Pharm Biomed Anal 2017; 144:269-278. [PMID: 28549853 DOI: 10.1016/j.jpba.2017.03.062] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 03/05/2017] [Accepted: 03/29/2017] [Indexed: 12/17/2022]
Abstract
Neurons are often classified by their morphological and molecular properties. The online knowledge base Hippocampome.org primarily defines neuron types from the rodent hippocampal formation based on their main neurotransmitter (glutamate or GABA) and the spatial distributions of their axons and dendrites. For each neuron type, this open-access resource reports any and all published information regarding the presence or absence of known molecular markers, including calcium-binding proteins, neuropeptides, receptors, channels, transcription factors, and other molecules of biomedical relevance. The resulting chemical profile is relatively sparse: even for the best studied neuron types, the expression or lack thereof of fewer than 70 molecules has been firmly established to date. The mouse genome-wide in situ hybridization mapping of the Allen Brain Atlas provides a wealth of data that, when appropriately analyzed, can substantially augment the molecular marker knowledge in Hippocampome.org. Here we focus on the principal cell layers of dentate gyrus (DG), CA3, CA2, and CA1, which together contain approximately 90% of hippocampal neurons. These four anatomical parcels are densely packed with somata of mostly excitatory projection neurons. Thus, gene expression data for those layers can be justifiably linked to the respective principal neuron types: granule cells in DG and pyramidal cells in CA3, CA2, and CA1. In order to enable consistent interpretation across genes and regions, we screened the whole-genome dataset against known molecular markers of those neuron types. The resulting threshold values allow over 6000 very-high confidence (>99.5%) expressed/not-expressed assignments, expanding the biochemical information content of Hippocampome.org more than five-fold. Many of these newly identified molecular markers are potential pharmacological targets for major neurological and psychiatric conditions. Furthermore, our approach yields reasonable expression/non-expression estimates for every single gene in each of these four neuron types with >90% average confidence, providing a considerably complete genetic characterization of hippocampal principal neurons.
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Affiliation(s)
- D J Hamilton
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, United States.
| | - C M White
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, United States
| | - C L Rees
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, United States
| | - D W Wheeler
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, United States
| | - G A Ascoli
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, United States.
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55
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Hippocampal α-Synuclein in Dementia with Lewy Bodies Contributes to Memory Impairment and Is Consistent with Spread of Pathology. J Neurosci 2016; 37:1675-1684. [PMID: 28039370 DOI: 10.1523/jneurosci.3047-16.2016] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/07/2016] [Accepted: 12/11/2016] [Indexed: 11/21/2022] Open
Abstract
Despite considerable research to uncover them, the anatomic and neuropathologic correlates of memory impairment in dementia with Lewy bodies (DLB) remain unclear. While some studies have implicated Lewy bodies in the neocortex, others have pointed to α-synuclein pathology in the hippocampus. We systematically examined hippocampal Lewy pathology and its distribution in hippocampal subfields in 95 clinically and neuropathologically characterized human cases of DLB, finding that α-synuclein pathology was highest in two hippocampal-related subregions: the CA2 subfield and the entorhinal cortex (EC). While the EC had numerous classic somatic Lewy bodies, CA2 contained mainly Lewy neurites in presumed axon terminals, suggesting the involvement of the EC → CA2 circuitry in the pathogenesis of DLB symptoms. Clinicopathological correlations with measures of verbal and visual memory supported a role for EC Lewy pathology, but not CA2, in causing these memory deficits. Lewy pathology in CA1-the main output region for CA2-correlated best with results from memory testing despite a milder pathology. This result indicates that CA1 may be more functionally relevant than CA2 in the context of memory impairment in DLB. These correlations remained significant after controlling for several factors, including concurrent Alzheimer's pathology (neuritic plaques and neurofibrillary tangles) and the interval between time of testing and time of death. Our data suggest that although hippocampal Lewy pathology in DLB is predominant in CA2 and EC, memory performance correlates most strongly with CA1 burden.SIGNIFICANCE STATEMENT This study provides a detailed neuropathologic analysis of hippocampal Lewy pathology in human patients with autopsy-confirmed dementia with Lewy bodies. The approach-informed by regional molecular markers, concurrent Alzheimer's pathology analysis, and relevant clinical data-helps tease out the relative contribution of Lewy pathology to memory dysfunction in the disease. Levels of Lewy pathology were found to be highest in the hippocampal CA2 subregion and entorhinal cortex, implicating a potentially overlooked circuit in disease pathogenesis. However, correlation with memory performance was strongest with CA1. This unexpected finding suggests that Lewy pathology must reach a critical burden across hippocampal circuitry to contribute to memory dysfunction beyond that related to other factors, notably coexisting Alzheimer's disease tau pathology.
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56
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Witchey SK, Stevenson EL, Caldwell HK. Genotypic differences in intruder-evoked immediate early gene activation in male, but not female, vasopressin 1b receptor knockout mice. BMC Neurosci 2016; 17:75. [PMID: 27881080 PMCID: PMC5122005 DOI: 10.1186/s12868-016-0310-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 11/16/2016] [Indexed: 12/27/2022] Open
Abstract
Background The neuropeptide arginine vasopressin (Avp) modulates social behaviors via its two centrally expressed receptors, the Avp 1a receptor and the Avp 1b receptor (Avpr1b). Recent work suggests that, at least in mice, Avp signaling through Avpr1b within the CA2 region of the hippocampus is critical for normal aggressive behaviors and social recognition memory. However, this brain area is just one part of a larger neural circuit that is likely to be impacted in Avpr1b knockout (−/−) mice. To identify other brain areas that are affected by altered Avpr1b signaling, genotypic differences in immediate early gene activation, i.e. c-FOS and early growth response factor 1 (EGR-1), were quantified using immunocytochemistry following a single exposure to an intruder. Results In females, no genotypic differences in intruder-evoked c-FOS or EGR-1 immunoreactivity were observed in any of the brain areas measured. In males, while there were no intruder-evoked genotypic differences in c-FOS immunoreactivity, genotypic differences were observed in EGR-1 immunoreactivity within the ventral bed nucleus of the stria terminalis and the anterior hypothalamus; with Avpr1b −/− males having less EGR-1 immunoreactivity in these regions than controls. Conclusions These data are the first to identify specific brain areas that may be a part of a neural circuit that includes Avpr1b-expressing cells in the CA2 region of the hippocampus. It is thought that this circuit, when working properly, plays a role in how an animal evaluates its social context. Electronic supplementary material The online version of this article (doi:10.1186/s12868-016-0310-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shannah K Witchey
- Laboratory of Neuroendocrinology and Behavior, Department of Biological Sciences, Kent State University, 256 Cunningham Hall, Kent, OH, 44242, USA
| | - Erica L Stevenson
- Laboratory of Neuroendocrinology and Behavior, Department of Biological Sciences, Kent State University, 256 Cunningham Hall, Kent, OH, 44242, USA.,Laboratory of Neuroendocrinology and Behavior, School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Heather K Caldwell
- Laboratory of Neuroendocrinology and Behavior, Department of Biological Sciences, Kent State University, 256 Cunningham Hall, Kent, OH, 44242, USA. .,Laboratory of Neuroendocrinology and Behavior, School of Biomedical Sciences, Kent State University, Kent, OH, USA.
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57
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Oliva A, Fernández-Ruiz A, Buzsáki G, Berényi A. Spatial coding and physiological properties of hippocampal neurons in the Cornu Ammonis subregions. Hippocampus 2016; 26:1593-1607. [PMID: 27650887 DOI: 10.1002/hipo.22659] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2016] [Indexed: 12/12/2022]
Abstract
It is well-established that the feed-forward connected main hippocampal areas, CA3, CA2, and CA1 work cooperatively during spatial navigation and memory. These areas are similar in terms of the prevalent types of neurons; however, they display different spatial coding and oscillatory dynamics. Understanding the temporal dynamics of these operations requires simultaneous recordings from these regions. However, simultaneous recordings from multiple regions and subregions in behaving animals have become possible only recently. We performed large-scale silicon probe recordings simultaneously spanning across all layers of CA1, CA2, and CA3 regions in rats during spatial navigation and sleep and compared their behavior-dependent spiking, oscillatory dynamics and functional connectivity. The accuracy of place cell spatial coding increased progressively from distal to proximal CA1, suddenly dropped in CA2, and increased again from CA3a toward CA3c. These variations can be attributed in part to the different entorhinal inputs to each subregions, and the differences in theta modulation of CA1, CA2, and CA3 neurons. We also found that neurons in the subregions showed differences in theta modulation, phase precession, state-dependent changes in firing rates and functional connectivity among neurons of these regions. Our results indicate that a combination of intrinsic properties together with distinct intra- and extra-hippocampal inputs may account for the subregion-specific modulation of spiking dynamics and spatial tuning of neurons during behavior. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Azahara Oliva
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary
| | - Antonio Fernández-Ruiz
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary
| | - György Buzsáki
- New York University Neuroscience Institute, New York, New York.,Center for Neural Science, New York University, New York, New York
| | - Antal Berényi
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary.,New York University Neuroscience Institute, New York, New York
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58
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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: 159] [Impact Index Per Article: 19.9] [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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59
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Rodriguez RD, Suemoto CK, Molina M, Nascimento CF, Leite REP, de Lucena Ferretti-Rebustini RE, Farfel JM, Heinsen H, Nitrini R, Ueda K, Pasqualucci CA, Jacob-Filho W, Yaffe K, Grinberg LT. Argyrophilic Grain Disease: Demographics, Clinical, and Neuropathological Features From a Large Autopsy Study. J Neuropathol Exp Neurol 2016; 75:628-35. [PMID: 27283329 DOI: 10.1093/jnen/nlw034] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Argyrophilic grain disease (AGD) is a frequent late-onset, 4-repeat tauopathy reported in Caucasians with high educational attainment. Little is known about AGD in non-Caucasians or in those with low educational attainment. We describe AGD demographics, clinical, and neuropathological features in a multiethnic cohort of 983 subjects ≥50 years of age from São Paulo, Brazil. Clinical data were collected through semistructured interviews with an informant and included in the Informant Questionnaire on Cognitive Decline in the Elderly, the Clinical Dementia Rating, and the Neuropsychiatric Inventory. Neuropathologic assessment relied on internationally accepted criteria. AGD was frequent (15.2%) and was the only neuropathological diagnosis in 8.9% of all cases (mean, 78.9 ± 9.4 years); it rarely occurred as an isolated neuropathological finding. AGD was associated with older age, lower socioeconomic status (SES), and appetite disorders. This is the first study of demographic, clinical, and neuropathological aspects of AGD in different ethnicities and subjects from all socioeconomic strata. The results suggest that prospective studies of AGD patients include levels of hormones related to appetite control as possible antemortem markers. Moreover, understanding the mechanisms behind higher susceptibility to AGD of low SES subjects may disclose novel environmental risk factors for AGD and other neurodegenerative diseases.
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Affiliation(s)
- Roberta Diehl Rodriguez
- From the Discipline of Pathophysiology (RDR, MM, CFN), Behavioral and Cognitive Neurology Unit, Department of Neurology (RDR, RN), Brazilian Brain Bank of the Aging Brain Study Group, LIM-22 (CKS, REPL, REdLF-R, JMF, HH, RN, CAP, WJ-F, LTG), Discipline of Geriatrics, University of São Paulo, São Paulo, Brazil (CKS, REPL, JMF, WJ-F); Medical-Surgical Nursing Department, University of São Paulo School of Nursing, São Paulo, Brazil (REdLF-R); Department of Pathology, University of São Paulo, São Paulo, Brazil (HH, CAP, LTG); Department of Psychiatry, Morphological Brain Research Unit, University of Würzburg, Würzburg, Germany (HH); Department of Neurochemistry, Tokyo Institute of Psychiatry, Setagaya-ku/Tokyo, Japan (KU); Memory and Aging Center, Department of Neurology and Pathology (KY, LTG); and Department of Psychiatry, University of California, San Francisco, California (KY)
| | - Claudia Kimie Suemoto
- From the Discipline of Pathophysiology (RDR, MM, CFN), Behavioral and Cognitive Neurology Unit, Department of Neurology (RDR, RN), Brazilian Brain Bank of the Aging Brain Study Group, LIM-22 (CKS, REPL, REdLF-R, JMF, HH, RN, CAP, WJ-F, LTG), Discipline of Geriatrics, University of São Paulo, São Paulo, Brazil (CKS, REPL, JMF, WJ-F); Medical-Surgical Nursing Department, University of São Paulo School of Nursing, São Paulo, Brazil (REdLF-R); Department of Pathology, University of São Paulo, São Paulo, Brazil (HH, CAP, LTG); Department of Psychiatry, Morphological Brain Research Unit, University of Würzburg, Würzburg, Germany (HH); Department of Neurochemistry, Tokyo Institute of Psychiatry, Setagaya-ku/Tokyo, Japan (KU); Memory and Aging Center, Department of Neurology and Pathology (KY, LTG); and Department of Psychiatry, University of California, San Francisco, California (KY)
| | - Mariana Molina
- From the Discipline of Pathophysiology (RDR, MM, CFN), Behavioral and Cognitive Neurology Unit, Department of Neurology (RDR, RN), Brazilian Brain Bank of the Aging Brain Study Group, LIM-22 (CKS, REPL, REdLF-R, JMF, HH, RN, CAP, WJ-F, LTG), Discipline of Geriatrics, University of São Paulo, São Paulo, Brazil (CKS, REPL, JMF, WJ-F); Medical-Surgical Nursing Department, University of São Paulo School of Nursing, São Paulo, Brazil (REdLF-R); Department of Pathology, University of São Paulo, São Paulo, Brazil (HH, CAP, LTG); Department of Psychiatry, Morphological Brain Research Unit, University of Würzburg, Würzburg, Germany (HH); Department of Neurochemistry, Tokyo Institute of Psychiatry, Setagaya-ku/Tokyo, Japan (KU); Memory and Aging Center, Department of Neurology and Pathology (KY, LTG); and Department of Psychiatry, University of California, San Francisco, California (KY)
| | - Camila Fernandes Nascimento
- From the Discipline of Pathophysiology (RDR, MM, CFN), Behavioral and Cognitive Neurology Unit, Department of Neurology (RDR, RN), Brazilian Brain Bank of the Aging Brain Study Group, LIM-22 (CKS, REPL, REdLF-R, JMF, HH, RN, CAP, WJ-F, LTG), Discipline of Geriatrics, University of São Paulo, São Paulo, Brazil (CKS, REPL, JMF, WJ-F); Medical-Surgical Nursing Department, University of São Paulo School of Nursing, São Paulo, Brazil (REdLF-R); Department of Pathology, University of São Paulo, São Paulo, Brazil (HH, CAP, LTG); Department of Psychiatry, Morphological Brain Research Unit, University of Würzburg, Würzburg, Germany (HH); Department of Neurochemistry, Tokyo Institute of Psychiatry, Setagaya-ku/Tokyo, Japan (KU); Memory and Aging Center, Department of Neurology and Pathology (KY, LTG); and Department of Psychiatry, University of California, San Francisco, California (KY)
| | - Renata Elaine Paraizo Leite
- From the Discipline of Pathophysiology (RDR, MM, CFN), Behavioral and Cognitive Neurology Unit, Department of Neurology (RDR, RN), Brazilian Brain Bank of the Aging Brain Study Group, LIM-22 (CKS, REPL, REdLF-R, JMF, HH, RN, CAP, WJ-F, LTG), Discipline of Geriatrics, University of São Paulo, São Paulo, Brazil (CKS, REPL, JMF, WJ-F); Medical-Surgical Nursing Department, University of São Paulo School of Nursing, São Paulo, Brazil (REdLF-R); Department of Pathology, University of São Paulo, São Paulo, Brazil (HH, CAP, LTG); Department of Psychiatry, Morphological Brain Research Unit, University of Würzburg, Würzburg, Germany (HH); Department of Neurochemistry, Tokyo Institute of Psychiatry, Setagaya-ku/Tokyo, Japan (KU); Memory and Aging Center, Department of Neurology and Pathology (KY, LTG); and Department of Psychiatry, University of California, San Francisco, California (KY)
| | - Renata Eloah de Lucena Ferretti-Rebustini
- From the Discipline of Pathophysiology (RDR, MM, CFN), Behavioral and Cognitive Neurology Unit, Department of Neurology (RDR, RN), Brazilian Brain Bank of the Aging Brain Study Group, LIM-22 (CKS, REPL, REdLF-R, JMF, HH, RN, CAP, WJ-F, LTG), Discipline of Geriatrics, University of São Paulo, São Paulo, Brazil (CKS, REPL, JMF, WJ-F); Medical-Surgical Nursing Department, University of São Paulo School of Nursing, São Paulo, Brazil (REdLF-R); Department of Pathology, University of São Paulo, São Paulo, Brazil (HH, CAP, LTG); Department of Psychiatry, Morphological Brain Research Unit, University of Würzburg, Würzburg, Germany (HH); Department of Neurochemistry, Tokyo Institute of Psychiatry, Setagaya-ku/Tokyo, Japan (KU); Memory and Aging Center, Department of Neurology and Pathology (KY, LTG); and Department of Psychiatry, University of California, San Francisco, California (KY)
| | - José Marcelo Farfel
- From the Discipline of Pathophysiology (RDR, MM, CFN), Behavioral and Cognitive Neurology Unit, Department of Neurology (RDR, RN), Brazilian Brain Bank of the Aging Brain Study Group, LIM-22 (CKS, REPL, REdLF-R, JMF, HH, RN, CAP, WJ-F, LTG), Discipline of Geriatrics, University of São Paulo, São Paulo, Brazil (CKS, REPL, JMF, WJ-F); Medical-Surgical Nursing Department, University of São Paulo School of Nursing, São Paulo, Brazil (REdLF-R); Department of Pathology, University of São Paulo, São Paulo, Brazil (HH, CAP, LTG); Department of Psychiatry, Morphological Brain Research Unit, University of Würzburg, Würzburg, Germany (HH); Department of Neurochemistry, Tokyo Institute of Psychiatry, Setagaya-ku/Tokyo, Japan (KU); Memory and Aging Center, Department of Neurology and Pathology (KY, LTG); and Department of Psychiatry, University of California, San Francisco, California (KY)
| | - Helmut Heinsen
- From the Discipline of Pathophysiology (RDR, MM, CFN), Behavioral and Cognitive Neurology Unit, Department of Neurology (RDR, RN), Brazilian Brain Bank of the Aging Brain Study Group, LIM-22 (CKS, REPL, REdLF-R, JMF, HH, RN, CAP, WJ-F, LTG), Discipline of Geriatrics, University of São Paulo, São Paulo, Brazil (CKS, REPL, JMF, WJ-F); Medical-Surgical Nursing Department, University of São Paulo School of Nursing, São Paulo, Brazil (REdLF-R); Department of Pathology, University of São Paulo, São Paulo, Brazil (HH, CAP, LTG); Department of Psychiatry, Morphological Brain Research Unit, University of Würzburg, Würzburg, Germany (HH); Department of Neurochemistry, Tokyo Institute of Psychiatry, Setagaya-ku/Tokyo, Japan (KU); Memory and Aging Center, Department of Neurology and Pathology (KY, LTG); and Department of Psychiatry, University of California, San Francisco, California (KY)
| | - Ricardo Nitrini
- From the Discipline of Pathophysiology (RDR, MM, CFN), Behavioral and Cognitive Neurology Unit, Department of Neurology (RDR, RN), Brazilian Brain Bank of the Aging Brain Study Group, LIM-22 (CKS, REPL, REdLF-R, JMF, HH, RN, CAP, WJ-F, LTG), Discipline of Geriatrics, University of São Paulo, São Paulo, Brazil (CKS, REPL, JMF, WJ-F); Medical-Surgical Nursing Department, University of São Paulo School of Nursing, São Paulo, Brazil (REdLF-R); Department of Pathology, University of São Paulo, São Paulo, Brazil (HH, CAP, LTG); Department of Psychiatry, Morphological Brain Research Unit, University of Würzburg, Würzburg, Germany (HH); Department of Neurochemistry, Tokyo Institute of Psychiatry, Setagaya-ku/Tokyo, Japan (KU); Memory and Aging Center, Department of Neurology and Pathology (KY, LTG); and Department of Psychiatry, University of California, San Francisco, California (KY)
| | - Kenji Ueda
- From the Discipline of Pathophysiology (RDR, MM, CFN), Behavioral and Cognitive Neurology Unit, Department of Neurology (RDR, RN), Brazilian Brain Bank of the Aging Brain Study Group, LIM-22 (CKS, REPL, REdLF-R, JMF, HH, RN, CAP, WJ-F, LTG), Discipline of Geriatrics, University of São Paulo, São Paulo, Brazil (CKS, REPL, JMF, WJ-F); Medical-Surgical Nursing Department, University of São Paulo School of Nursing, São Paulo, Brazil (REdLF-R); Department of Pathology, University of São Paulo, São Paulo, Brazil (HH, CAP, LTG); Department of Psychiatry, Morphological Brain Research Unit, University of Würzburg, Würzburg, Germany (HH); Department of Neurochemistry, Tokyo Institute of Psychiatry, Setagaya-ku/Tokyo, Japan (KU); Memory and Aging Center, Department of Neurology and Pathology (KY, LTG); and Department of Psychiatry, University of California, San Francisco, California (KY)
| | - Carlos Augusto Pasqualucci
- From the Discipline of Pathophysiology (RDR, MM, CFN), Behavioral and Cognitive Neurology Unit, Department of Neurology (RDR, RN), Brazilian Brain Bank of the Aging Brain Study Group, LIM-22 (CKS, REPL, REdLF-R, JMF, HH, RN, CAP, WJ-F, LTG), Discipline of Geriatrics, University of São Paulo, São Paulo, Brazil (CKS, REPL, JMF, WJ-F); Medical-Surgical Nursing Department, University of São Paulo School of Nursing, São Paulo, Brazil (REdLF-R); Department of Pathology, University of São Paulo, São Paulo, Brazil (HH, CAP, LTG); Department of Psychiatry, Morphological Brain Research Unit, University of Würzburg, Würzburg, Germany (HH); Department of Neurochemistry, Tokyo Institute of Psychiatry, Setagaya-ku/Tokyo, Japan (KU); Memory and Aging Center, Department of Neurology and Pathology (KY, LTG); and Department of Psychiatry, University of California, San Francisco, California (KY)
| | - Wilson Jacob-Filho
- From the Discipline of Pathophysiology (RDR, MM, CFN), Behavioral and Cognitive Neurology Unit, Department of Neurology (RDR, RN), Brazilian Brain Bank of the Aging Brain Study Group, LIM-22 (CKS, REPL, REdLF-R, JMF, HH, RN, CAP, WJ-F, LTG), Discipline of Geriatrics, University of São Paulo, São Paulo, Brazil (CKS, REPL, JMF, WJ-F); Medical-Surgical Nursing Department, University of São Paulo School of Nursing, São Paulo, Brazil (REdLF-R); Department of Pathology, University of São Paulo, São Paulo, Brazil (HH, CAP, LTG); Department of Psychiatry, Morphological Brain Research Unit, University of Würzburg, Würzburg, Germany (HH); Department of Neurochemistry, Tokyo Institute of Psychiatry, Setagaya-ku/Tokyo, Japan (KU); Memory and Aging Center, Department of Neurology and Pathology (KY, LTG); and Department of Psychiatry, University of California, San Francisco, California (KY)
| | - Kristine Yaffe
- From the Discipline of Pathophysiology (RDR, MM, CFN), Behavioral and Cognitive Neurology Unit, Department of Neurology (RDR, RN), Brazilian Brain Bank of the Aging Brain Study Group, LIM-22 (CKS, REPL, REdLF-R, JMF, HH, RN, CAP, WJ-F, LTG), Discipline of Geriatrics, University of São Paulo, São Paulo, Brazil (CKS, REPL, JMF, WJ-F); Medical-Surgical Nursing Department, University of São Paulo School of Nursing, São Paulo, Brazil (REdLF-R); Department of Pathology, University of São Paulo, São Paulo, Brazil (HH, CAP, LTG); Department of Psychiatry, Morphological Brain Research Unit, University of Würzburg, Würzburg, Germany (HH); Department of Neurochemistry, Tokyo Institute of Psychiatry, Setagaya-ku/Tokyo, Japan (KU); Memory and Aging Center, Department of Neurology and Pathology (KY, LTG); and Department of Psychiatry, University of California, San Francisco, California (KY)
| | - Lea Tenenholz Grinberg
- From the Discipline of Pathophysiology (RDR, MM, CFN), Behavioral and Cognitive Neurology Unit, Department of Neurology (RDR, RN), Brazilian Brain Bank of the Aging Brain Study Group, LIM-22 (CKS, REPL, REdLF-R, JMF, HH, RN, CAP, WJ-F, LTG), Discipline of Geriatrics, University of São Paulo, São Paulo, Brazil (CKS, REPL, JMF, WJ-F); Medical-Surgical Nursing Department, University of São Paulo School of Nursing, São Paulo, Brazil (REdLF-R); Department of Pathology, University of São Paulo, São Paulo, Brazil (HH, CAP, LTG); Department of Psychiatry, Morphological Brain Research Unit, University of Würzburg, Würzburg, Germany (HH); Department of Neurochemistry, Tokyo Institute of Psychiatry, Setagaya-ku/Tokyo, Japan (KU); Memory and Aging Center, Department of Neurology and Pathology (KY, LTG); and Department of Psychiatry, University of California, San Francisco, California (KY).
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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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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: 276] [Impact Index Per Article: 34.5] [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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62
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Schulman JJ, Wright FA, Han X, Zluhan EJ, Szczesniak LM, Wojcikiewicz RJH. The Stability and Expression Level of Bok Are Governed by Binding to Inositol 1,4,5-Trisphosphate Receptors. J Biol Chem 2016; 291:11820-8. [PMID: 27053113 DOI: 10.1074/jbc.m115.711242] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Indexed: 12/31/2022] Open
Abstract
Bok is a member of the Bcl-2 protein family that governs the intrinsic apoptosis pathway, although the role that Bok plays in this pathway is unclear. We have shown previously in cultured cell lines that Bok interacts strongly with inositol 1,4,5-trisphosphate receptors (IP3Rs), suggesting that it may contribute to the structural integrity or stability of IP3R tetramers. Here we report that Bok is similarly IP3R-assocated in mouse tissues, that essentially all cellular Bok is IP3R bound, that it is the helical nature of the Bok BH4 domain, rather than specific amino acids, that mediates binding to IP3Rs, that Bok is dramatically stabilized by binding to IP3Rs, that unbound Bok is ubiquitinated and degraded by the proteasome, and that binding to IP3Rs limits the pro-apoptotic effect of overexpressed Bok. Agents that stimulate IP3R activity, apoptosis, phosphorylation, and endoplasmic reticulum stress did not trigger the dissociation of mature Bok from IP3Rs or Bok degradation, indicating that the role of proteasome-mediated Bok degradation is to destroy newly synthesized Bok that is not IP3R associated. The existence of this unexpected proteolytic mechanism that is geared toward restricting Bok to that which is bound to IP3Rs, implies that unbound Bok is deleterious to cell viability and helps explain the current uncertainty regarding the cellular role of Bok.
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Affiliation(s)
- Jacqualyn J Schulman
- From the Department of Pharmacology, SUNY Upstate Medical University, Syracuse, New York 13210
| | - Forrest A Wright
- From the Department of Pharmacology, SUNY Upstate Medical University, Syracuse, New York 13210
| | - Xiaobing Han
- From the Department of Pharmacology, SUNY Upstate Medical University, Syracuse, New York 13210
| | - Eric J Zluhan
- From the Department of Pharmacology, SUNY Upstate Medical University, Syracuse, New York 13210
| | - Laura M Szczesniak
- From the Department of Pharmacology, SUNY Upstate Medical University, Syracuse, New York 13210
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63
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Alexander GM, Farris S, Pirone JR, Zheng C, Colgin LL, Dudek SM. Social and novel contexts modify hippocampal CA2 representations of space. Nat Commun 2016; 7:10300. [PMID: 26806606 PMCID: PMC4737730 DOI: 10.1038/ncomms10300] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 11/27/2015] [Indexed: 01/01/2023] Open
Abstract
The hippocampus supports a cognitive map of space and is critical for encoding declarative memory (who, what, when and where). Recent studies have implicated hippocampal subfield CA2 in social and contextual memory but how it does so remains unknown. Here we find that in adult male rats, presentation of a social stimulus (novel or familiar rat) or a novel object induces global remapping of place fields in CA2 with no effect on neuronal firing rate or immediate early gene expression. This remapping did not occur in CA1, suggesting this effect is specific for CA2. Thus, modification of existing spatial representations might be a potential mechanism by which CA2 encodes social and novel contextual information.
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Affiliation(s)
- Georgia M. Alexander
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T.W. Alexander Drive, Mail Drop F2-04, Research Triangle Park, North Carolina 27709, USA
| | - Shannon Farris
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T.W. Alexander Drive, Mail Drop F2-04, Research Triangle Park, North Carolina 27709, USA
| | - Jason R. Pirone
- Social and Scientific Systems, Inc., 1009 Slater Road Suite 120, Durham, North Carolina 27703, USA
| | - Chenguang Zheng
- Center for Learning and Memory, The University of Texas at Austin, 1 University Station Stop C7000, NMS 4.104, Austin, Texas 78712, USA
- Department of Neuroscience, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Laura L. Colgin
- Center for Learning and Memory, The University of Texas at Austin, 1 University Station Stop C7000, NMS 4.104, Austin, Texas 78712, USA
- Department of Neuroscience, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Serena M. Dudek
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T.W. Alexander Drive, Mail Drop F2-04, Research Triangle Park, North Carolina 27709, USA
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64
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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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Basu J, Siegelbaum SA. The Corticohippocampal Circuit, Synaptic Plasticity, and Memory. Cold Spring Harb Perspect Biol 2015; 7:7/11/a021733. [PMID: 26525152 DOI: 10.1101/cshperspect.a021733] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Synaptic plasticity serves as a cellular substrate for information storage in the central nervous system. The entorhinal cortex (EC) and hippocampus are interconnected brain areas supporting basic cognitive functions important for the formation and retrieval of declarative memories. Here, we discuss how information flow in the EC-hippocampal loop is organized through circuit design. We highlight recently identified corticohippocampal and intrahippocampal connections and how these long-range and local microcircuits contribute to learning. This review also describes various forms of activity-dependent mechanisms that change the strength of corticohippocampal synaptic transmission. A key point to emerge from these studies is that patterned activity and interaction of coincident inputs gives rise to associational plasticity and long-term regulation of information flow. Finally, we offer insights about how learning-related synaptic plasticity within the corticohippocampal circuit during sensory experiences may enable adaptive behaviors for encoding spatial, episodic, social, and contextual memories.
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Affiliation(s)
- Jayeeta Basu
- Department of Neuroscience and Physiology, NYU Neuroscience Institute, New York University School of Medicine, New York, New York 10016
| | - Steven A Siegelbaum
- Kavli Institute for Brain Science, Columbia University, New York, New York 10032 Department of Neuroscience, Columbia University, New York, New York 10032 Department of Pharmacology, Columbia University, New York, New York 10032
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66
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Lu L, Igarashi K, Witter M, Moser E, Moser MB. Topography of Place Maps along the CA3-to-CA2 Axis of the Hippocampus. Neuron 2015; 87:1078-92. [DOI: 10.1016/j.neuron.2015.07.007] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 06/23/2015] [Accepted: 07/13/2015] [Indexed: 10/23/2022]
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Lee H, Wang C, Deshmukh SS, Knierim JJ. Neural Population Evidence of Functional Heterogeneity along the CA3 Transverse Axis: Pattern Completion versus Pattern Separation. Neuron 2015; 87:1093-105. [PMID: 26298276 DOI: 10.1016/j.neuron.2015.07.012] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 06/25/2015] [Accepted: 07/17/2015] [Indexed: 10/23/2022]
Abstract
Classical theories of associative memory model CA3 as a homogeneous attractor network because of its strong recurrent circuitry. However, anatomical gradients suggest a functional diversity along the CA3 transverse axis. We examined the neural population coherence along this axis, when the local and global spatial reference frames were put in conflict with each other. Proximal CA3 (near the dentate gyrus), where the recurrent collaterals are the weakest, showed degraded representations, similar to the pattern separation shown by the dentate gyrus. Distal CA3 (near CA2), where the recurrent collaterals are the strongest, maintained coherent representations in the conflict situation, resembling the classic attractor network system. CA2 also maintained coherent representations. This dissociation between proximal and distal CA3 provides strong evidence that the recurrent collateral system underlies the associative network functions of CA3, with a separate role of proximal CA3 in pattern separation.
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Affiliation(s)
- Heekyung Lee
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Cheng Wang
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Sachin S Deshmukh
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA
| | - James J Knierim
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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68
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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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69
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Evans PR, Dudek SM, Hepler JR. Regulator of G Protein Signaling 14: A Molecular Brake on Synaptic Plasticity Linked to Learning and Memory. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 133:169-206. [PMID: 26123307 DOI: 10.1016/bs.pmbts.2015.03.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The regulators of G protein signaling (RGS) proteins are a diverse family of proteins that function as central components of G protein and other signaling pathways. In the brain, regulator of G protein signaling 14 (RGS14) is enriched in neurons in the hippocampus where the mRNA and protein are highly expressed. This brain region plays a major role in processing learning and forming new memories. RGS14 is an unusual RGS protein that acts as a multifunctional scaffolding protein to integrate signaling events and pathways essential for synaptic plasticity, including conventional and unconventional G protein signaling, mitogen-activated protein kinase, and, possibly, calcium signaling pathways. Within the hippocampus of primates and rodents, RGS14 is predominantly found in the enigmatic CA2 subfield. Principal neurons within the CA2 subfield differ from neighboring hippocampal regions in that they lack a capacity for long-term potentiation (LTP) of synaptic transmission, which is widely viewed as the cellular substrate of learning and memory formation. RGS14 was recently identified as a natural suppressor of LTP in hippocampal CA2 neurons as well as forms of learning and memory that depend on the hippocampus. Although CA2 has only recently been studied, compelling recent evidence implicates area CA2 as a critical component of hippocampus circuitry with functional roles in mediating certain types of learning and memory. This review will highlight the known functions of RGS14 in cell signaling and hippocampus physiology, and discuss potential roles for RGS14 in human cognition and disease.
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Affiliation(s)
- Paul R Evans
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, Atlanta, Georgia, USA
| | - Serena M Dudek
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - John R Hepler
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, Atlanta, Georgia, USA.
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70
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Role of the vasopressin 1b receptor in rodent aggressive behavior and synaptic plasticity in hippocampal area CA2. Mol Psychiatry 2015; 20:490-9. [PMID: 24863146 PMCID: PMC4562468 DOI: 10.1038/mp.2014.47] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 03/07/2014] [Accepted: 04/16/2014] [Indexed: 01/31/2023]
Abstract
The vasopressin 1b receptor (Avpr1b) is critical for social memory and social aggression in rodents, yet little is known about its specific roles in these behaviors. Some clues to Avpr1b function can be gained from its profile of expression in the brain, which is largely limited to the pyramidal neurons of the CA2 region of the hippocampus, and from experiments showing that inactivation of the gene or antagonism of the receptor leads to a reduction in social aggression. Here we show that partial replacement of the Avpr1b through lentiviral delivery into the dorsal CA2 region restored the probability of socially motivated attack behavior in total Avpr1b knockout mice, without altering anxiety-like behaviors. To further explore the role of the Avpr1b in this hippocampal region, we examined the effects of Avpr1b agonists on pyramidal neurons in mouse and rat hippocampal slices. We found that selective Avpr1b agonists induced significant potentiation of excitatory synaptic responses in CA2, but not in CA1 or in slices from Avpr1b knockout mice. In a way that is mechanistically very similar to synaptic potentiation induced by oxytocin, Avpr1b agonist-induced potentiation of CA2 synapses relies on NMDA (N-methyl-D-aspartic acid) receptor activation, calcium and calcium/calmodulin-dependent protein kinase II activity, but not on cAMP-dependent protein kinase activity or presynaptic mechanisms. Our data indicate that the hippocampal CA2 is important for attacking in response to a male intruder and that the Avpr1b, likely through its role in regulating CA2 synaptic plasticity, is a necessary mediator.
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71
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Shi Y, Ikrar T, Olivas ND, Xu X. Bidirectional global spontaneous network activity precedes the canonical unidirectional circuit organization in the developing hippocampus. J Comp Neurol 2015; 522:2191-208. [PMID: 24357090 PMCID: PMC4293468 DOI: 10.1002/cne.23528] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Revised: 11/22/2013] [Accepted: 12/17/2013] [Indexed: 11/27/2022]
Abstract
Spontaneous network activity is believed to sculpt developing neural circuits. Spontaneous giant depolarizing potentials (GDPs) were first identified with single-cell recordings from rat CA3 pyramidal neurons, but here we identify and characterize a large-scale spontaneous network activity we term global network activation (GNA) in the developing mouse hippocampal slices, which is measured macroscopically by fast voltage-sensitive dye imaging. The initiation and propagation of GNA in the mouse is largely GABA-independent and dominated by glutamatergic transmission via AMPA receptors. Despite the fact that signal propagation in the adult hippocampus is strongly unidirectional through the canonical trisynaptic circuit (dentate gyrus [DG] to CA3 to CA1), spontaneous GNA in the developing hippocampus originates in distal CA3 and propagates both forward to CA1 and backward to DG. Photostimulation-evoked GNA also shows prominent backward propagation in the developing hippocampus from CA3 to DG. Mouse GNA is strongly correlated to electrophysiological recordings of highly localized single-cell and local field potential events. Photostimulation mapping of neural circuitry demonstrates that the enhancement of local circuit connections to excitatory pyramidal neurons occurs over the same time course as GNA and reveals the underlying pathways accounting for GNA backward propagation from CA3 to DG. The disappearance of GNA coincides with a transition to the adult-like unidirectional circuit organization at about 2 weeks of age. Taken together, our findings strongly suggest a critical link between GNA activity and maturation of functional circuit connections in the developing hippocampus.
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Affiliation(s)
- Yulin Shi
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, California, 92697-1275
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Maggi R, Zasso J, Conti L. Neurodevelopmental origin and adult neurogenesis of the neuroendocrine hypothalamus. Front Cell Neurosci 2015; 8:440. [PMID: 25610370 PMCID: PMC4285089 DOI: 10.3389/fncel.2014.00440] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 12/06/2014] [Indexed: 11/13/2022] Open
Abstract
The adult hypothalamus regulates many physiological functions and homeostatic loops, including growth, feeding and reproduction. In mammals, the hypothalamus derives from the ventral diencephalon where two distinct ventricular proliferative zones have been described. Although a set of transcription factors regulating the hypothalamic development has been identified, the exact molecular mechanisms that drive the differentiation of hypothalamic neural precursor cells (NPCs) toward specific neuroendocrine neuronal subtypes is yet not fully disclosed. Neurogenesis has been also reported in the adult hypothalamus at the level of specific niches located in the ventrolateral region of ventricle wall, where NPCs have been identified as radial glia-like tanycytes. Here we review the molecular and cellular systems proposed to support the neurogenic potential of developing and adult hypothalamic NPCs. We also report new insights on the mechanisms by which adult hypothalamic neurogenesis modulates key functions of this brain region. Finally, we discuss how environmental factors may modulate the adult hypothalamic neurogenic cascade.
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Affiliation(s)
- Roberto Maggi
- Laboratory of Developmental Neuroendocrinology, Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano Milano, Italy ; Interuniversity Centre for the Research on the Molecular Bases of Reproductive Diseases (CIRMAR) Milano, Italy
| | - Jacopo Zasso
- Centre for Integrative Biology (CIBIO), Università degli Studi di Trento Povo, Italy
| | - Luciano Conti
- Centre for Integrative Biology (CIBIO), Università degli Studi di Trento Povo, Italy
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73
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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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74
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Stevenson EL, Caldwell HK. Lesions to the CA2 region of the hippocampus impair social memory in mice. Eur J Neurosci 2014; 40:3294-301. [PMID: 25131412 DOI: 10.1111/ejn.12689] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 06/29/2014] [Accepted: 07/11/2014] [Indexed: 12/26/2022]
Abstract
The function of the CA2 region of the hippocampus is poorly understood. Although the CA1 and CA3 regions have been extensively studied, for years the CA2 region has primarily been viewed as a linking area between the two. However, the CA2 region is known to have distinct neurochemical and structural features that are different from the other parts of the hippocampus and in recent years it has been suggested that the CA2 region may play a role in the formation and/or recall of olfactory-based memories needed for normal social behavior. Although this hypothesis has been supported by hippocampal lesion studies that have included the CA2 region, no studies have attempted to specifically lesion the CA2 region of the hippocampus in mice to determine the effects on social recognition memory and olfaction. To fill this knowledge gap, we sought to perform excitotoxic N-methyl-D-aspartate lesions of the CA2 region and determine the effects on social recognition memory. We predicted that lesions of the CA2 region would impair social recognition memory. We then went on to test olfaction in CA2-lesioned mice, as social memory requires a functional olfactory system. Consistent with our prediction, we found that CA2-lesioned animals had impaired social recognition. These findings are significant because they confirmed that the CA2 region of the hippocampus is a part of the neural circuitry that regulates social recognition memory, which may have implications for our understanding of the neural regulation of social behavior across species.
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Affiliation(s)
- Erica L Stevenson
- Laboratory of Neuroendocrinology and Behavior, Department of Biological Sciences and the School of Biomedical Sciences, Kent State University, 121 Cunningham Hall, Kent, OH, 44242, USA
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75
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Renelt M, von Bohlen und Halbach V, von Bohlen und Halbach O. Distribution of PCP4 protein in the forebrain of adult mice. Acta Histochem 2014; 116:1056-61. [PMID: 24954028 DOI: 10.1016/j.acthis.2014.04.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/29/2014] [Accepted: 04/30/2014] [Indexed: 12/15/2022]
Abstract
Purkinje-cell protein 4 (PCP4) is a small calmodulin (CaM)-binding protein that has been discovered to be selectively expressed by cerebellar Purkinje cells in the adult rodent brain. In addition, expression of PCP4 mRNA has been detected in the hippocampus and in the cortex. In order to determine the expression of PCP4 protein in the brain, we performed an immunohistochemical analysis using adult mice. We could demonstrate that PCP4 is expressed in neocortical structures, especially in the deep layers, as well as in other cortical structures and parts of the hippocampal formation. Moreover, PCP4 protein is highly expressed in the olfactory bulb and caudate putamen. PCP4 positive cells were also detected in specific areas of the amygdala, thalamus (especially dorsal lateral geniculate nucleus) and hypothalamus. By performing double-labeling experiments together with NeuN (a neuronal marker), we could demonstrate that PCP4 expressing cells in the brain are of neuronal origin.
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Affiliation(s)
- Maria Renelt
- Institute of Anatomy and Cell Biology, Universitätsmedizin Greifswald, Friedrich-Loeffler-Str. 23c, D-17487 Greifswald, Germany
| | - Viola von Bohlen und Halbach
- Institute of Anatomy and Cell Biology, Universitätsmedizin Greifswald, Friedrich-Loeffler-Str. 23c, D-17487 Greifswald, Germany
| | - Oliver von Bohlen und Halbach
- Institute of Anatomy and Cell Biology, Universitätsmedizin Greifswald, Friedrich-Loeffler-Str. 23c, D-17487 Greifswald, Germany.
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76
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Sugiyama T, Osumi N, Katsuyama Y. A novel cell migratory zone in the developing hippocampal formation. J Comp Neurol 2014; 522:3520-38. [PMID: 24771490 DOI: 10.1002/cne.23621] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/25/2014] [Accepted: 04/25/2014] [Indexed: 11/08/2022]
Abstract
The hippocampal formation (HF) is a unique structure in the mammalian brain and is subdivided into the dentate gyrus, Ammon's horn, and subiculum by their functions and connectivity in the neuronal circuit. Because behaviors of the neural stem cells, neuronal progenitors, and the differentiating neurons are complex during hippocampal morphogenesis, the differentiation of these subdivisions has not been well understood. In this study, we investigated embryonic and postnatal expression of the proteins Prox1, Math2, and Ctip2, which clearly indicate principal cells of the dentate gyrus (Prox1 positive) and Ammon's horn (Math2 and Ctip2 positive). Expression patterns of Prox1 and Math2 were consistent with previously suggested localization of migratory pathways of the dentate granule cells and hippocampal pyramidal cells. Interestingly, we found intermingling of Prox1-expressing cells and Math2-expressing cells in a cell migratory stream, suggesting previously unknown behaviors of differentiating cells of the HF.
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Affiliation(s)
- Taku Sugiyama
- Department of Developmental Neuroscience, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
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77
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Abstract
Contextual learning involves associating cues with an environment and relating them to past experience. Previous data indicate functional specialization within the hippocampal circuit: the dentate gyrus (DG) is crucial for discriminating similar contexts, whereas CA3 is required for associative encoding and recall. Here, we used Arc/H1a catFISH imaging to address the contribution of the largely overlooked CA2 region to contextual learning by comparing ensemble codes across CA3, CA2, and CA1 in mice exposed to familiar, altered, and novel contexts. Further, to manipulate the quality of information arriving in CA2 we used two hippocampal mutant mouse lines, CA3-NR1 KOs and DG-NR1 KOs, that result in hippocampal CA3 neuronal activity that is uncoupled from the animal's sensory environment. Our data reveal largely coherent responses across the CA axis in control mice in purely novel or familiar contexts; however, in the mutant mice subject to these protocols the CA2 response becomes uncoupled from CA1 and CA3. Moreover, we show in wild-type mice that the CA2 ensemble is more sensitive than CA1 and CA3 to small changes in overall context. Our data suggest that CA2 may be tuned to remap in response to any conflict between stored and current experience.
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78
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Hitti FL, Siegelbaum SA. The hippocampal CA2 region is essential for social memory. Nature 2014; 508:88-92. [PMID: 24572357 PMCID: PMC4000264 DOI: 10.1038/nature13028] [Citation(s) in RCA: 628] [Impact Index Per Article: 62.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 01/10/2014] [Indexed: 02/08/2023]
Abstract
The hippocampus is critical for encoding declarative memory, our repository of knowledge of who, what, where and when. Mnemonic information is processed in the hippocampus through several parallel routes involving distinct subregions. In the classic trisynaptic pathway, information proceeds from entorhinal cortex (EC) to dentate gyrus to CA3 and then to CA1, the main hippocampal output. Genetic lesions of EC (ref. 3) and hippocampal dentate gyrus (ref. 4), CA3 (ref. 5) and CA1 (ref. 6) regions have revealed their distinct functions in learning and memory. In contrast, little is known about the role of CA2, a relatively small area interposed between CA3 and CA1 that forms the nexus of a powerful disynaptic circuit linking EC input with CA1 output. Here we report a novel transgenic mouse line that enabled us to selectively examine the synaptic connections and behavioural role of the CA2 region in adult mice. Genetically targeted inactivation of CA2 pyramidal neurons caused a pronounced loss of social memory--the ability of an animal to remember a conspecific--with no change in sociability or several other hippocampus-dependent behaviours, including spatial and contextual memory. These behavioural and anatomical results thus reveal CA2 as a critical hub of sociocognitive memory processing.
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Affiliation(s)
- Frederick L Hitti
- Department of Neuroscience, Kavli Institute, College of Physicians and Surgeons, Columbia University 1051 Riverside Drive, New York, New York 10032, USA
| | - Steven A Siegelbaum
- 1] Department of Neuroscience, Kavli Institute, College of Physicians and Surgeons, Columbia University 1051 Riverside Drive, New York, New York 10032, USA [2] Department of Pharmacology, Howard Hughes Medical Institute, College of Physicians and Surgeons, Columbia University 1051 Riverside Drive, New York, New York 10032, USA
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79
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Evans PR, Lee SE, Smith Y, Hepler JR. Postnatal developmental expression of regulator of G protein signaling 14 (RGS14) in the mouse brain. J Comp Neurol 2014; 522:186-203. [PMID: 23817783 PMCID: PMC3883939 DOI: 10.1002/cne.23395] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 04/22/2013] [Accepted: 06/19/2013] [Indexed: 12/13/2022]
Abstract
Regulator of G protein signaling 14 (RGS14) is a multifunctional scaffolding protein that integrates G protein and mitogen-activated protein kinase (MAPK) signaling pathways. In the adult mouse brain, RGS14 mRNA and protein are found almost exclusively in hippocampal CA2 neurons. We have shown that RGS14 is a natural suppressor of CA2 synaptic plasticity and hippocampal-dependent learning and memory. However, the protein distribution and spatiotemporal expression patterns of RGS14 in mouse brain during postnatal development are unknown. Here, using a newly characterized monoclonal anti-RGS14 antibody, we demonstrate that RGS14 protein immunoreactivity is undetectable at birth (P0), with very low mRNA expression in the brain. However, RGS14 protein and mRNA are upregulated during early postnatal development, with protein first detected at P7, and both increasing over time until reaching highest sustained levels throughout adulthood. Our immunoperoxidase data demonstrate that RGS14 protein is expressed in regions outside of hippocampal CA2 during development including the primary olfactory areas, the anterior olfactory nucleus and piriform cortex, and the olfactory associated orbital and entorhinal cortices. RGS14 is also transiently expressed in neocortical layers II/III and V during postnatal development. Finally, we show that RGS14 protein is first detected in the hippocampus at P7, with strongest immunoreactivity in CA2 and fasciola cinerea and sporadic immunoreactivity in CA1; labeling intensity in hippocampus increases until adulthood. These results show that RGS14 mRNA and protein are upregulated throughout postnatal mouse development, and RGS14 protein exhibits a dynamic localization pattern that is enriched in hippocampus and primary olfactory cortex in the adult mouse brain.
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Affiliation(s)
- Paul R Evans
- Department of Pharmacology, Emory University, Atlanta, Georgia, 30322
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80
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Cell type-specific genetic and optogenetic tools reveal hippocampal CA2 circuits. Nat Neurosci 2013; 17:269-79. [PMID: 24336151 PMCID: PMC4004172 DOI: 10.1038/nn.3614] [Citation(s) in RCA: 350] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 11/25/2013] [Indexed: 12/30/2022]
Abstract
The formation and recall of episodic memory requires precise information processing by the entorhinal-hippocampal network. For several decades, the trisynaptic circuit, entorhinal cortex layer II (ECII)→dentate gyrus (DG)→CA3→CA1 and the monosynaptic circuit ECIII→CA1 have been considered the main substrates of the network responsible for learning and memory. Circuits linked to another hippocampal region, CA2, have only recently come to light. Here, by using highly cell type-specific transgenic mouse lines, optogenetics, and patch-clamp recordings, we show that DG cells, long believed not to project to CA2, send functional monosynaptic inputs to CA2 pyramidal cells, through abundant longitudinal projections. CA2 innervates CA1 to complete an alternate trisynaptic circuit but, unlike CA3, projects preferentially to the deep rather than superficial sublayer of CA1. Furthermore, contrary to the current knowledge, ECIII does not project to CA2. These new anatomical results will allow for a deeper understanding of the biology of learning and memory.
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81
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Mouton-Liger F, Sahún I, Collin T, Lopes Pereira P, Masini D, Thomas S, Paly E, Luilier S, Même S, Jouhault Q, Bennaï S, Beloeil JC, Bizot JC, Hérault Y, Dierssen M, Créau N. Developmental molecular and functional cerebellar alterations induced by PCP4/PEP19 overexpression: implications for Down syndrome. Neurobiol Dis 2013; 63:92-106. [PMID: 24291518 DOI: 10.1016/j.nbd.2013.11.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 11/05/2013] [Accepted: 11/19/2013] [Indexed: 11/28/2022] Open
Abstract
PCP4/PEP19 is a modulator of Ca(2+)-CaM signaling. In the brain, it is expressed in a very specific pattern in postmitotic neurons. In particular, Pcp4 is highly expressed in the Purkinje cell, the sole output neuron of the cerebellum. PCP4, located on human chromosome 21, is present in three copies in individuals with Down syndrome (DS). In a previous study using a transgenic mouse model (TgPCP4) to evaluate the consequences of 3 copies of this gene, we found that PCP4 overexpression induces precocious neuronal differentiation during mouse embryogenesis. Here, we report combined analyses of the cerebellum at postnatal stages (P14 and adult) in which we identified age-related molecular, electrophysiological, and behavioral alterations in the TgPCP4 mouse. While Pcp4 overexpression at P14 induces an earlier neuronal maturation, at adult stage it induces increase in cerebellar CaMK2alpha and in cerebellar LTD, as well as learning impairments. We therefore propose that PCP4 contributes significantly to the development of Down syndrome phenotypes through molecular and functional changes.
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Affiliation(s)
- François Mouton-Liger
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, EAC4413 CNRS, Paris, France
| | - Ignasi Sahún
- Cellular and Systems Biology, Systems Biology Programme, Center for Genomic Regulation (CRG); Universitat Pompeu Fabra (UPF); Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER): Dr. Aiguader, 88, 08003 Barcelona, Spain
| | - Thibault Collin
- CNRS UMR8118, Brain Physiology Laboratory, Universite Paris-Descartes, Centre universitaire des Saints-Pères, 45 Rue des Saints-Pères, 75270 Paris Cedex 06, France
| | - Patricia Lopes Pereira
- Transgenese et Archivage Animaux Modèles, TAAM, CNRS, UPS44, 3B rue de la Férollerie, 45071 Orléans, France
| | - Debora Masini
- Cellular and Systems Biology, Systems Biology Programme, Center for Genomic Regulation (CRG); Universitat Pompeu Fabra (UPF); Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER): Dr. Aiguader, 88, 08003 Barcelona, Spain
| | - Sophie Thomas
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, EAC4413 CNRS, Paris, France
| | - Evelyne Paly
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, EAC4413 CNRS, Paris, France
| | - Sabrina Luilier
- Key-Obs SAS, 13 avenue Buffon, 45071 Orléans Cedex 2, France
| | - Sandra Même
- Centre de Biophysique Moléculaire, CNRS UPR 4301, Orléans, France
| | - Quentin Jouhault
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, EAC4413 CNRS, Paris, France
| | - Soumia Bennaï
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, EAC4413 CNRS, Paris, France
| | | | | | - Yann Hérault
- Transgenese et Archivage Animaux Modèles, TAAM, CNRS, UPS44, 3B rue de la Férollerie, 45071 Orléans, France; Institut Clinique de la Souris, ICS, 1 rue Laurent Fries, 67404 Illkirch, France; Institut de Génétique Biologie Moléculaire et Cellulaire, Translational medicine and Neuroscience program, IGBMC, CNRS, INSERM, Université de Strasbourg, UMR7104, UMR964, 1 rue Laurent Fries, 67404 Illkirch, France
| | - Mara Dierssen
- Cellular and Systems Biology, Systems Biology Programme, Center for Genomic Regulation (CRG); Universitat Pompeu Fabra (UPF); Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER): Dr. Aiguader, 88, 08003 Barcelona, Spain
| | - Nicole Créau
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, EAC4413 CNRS, Paris, France.
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82
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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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83
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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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84
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Watakabe A, Hirokawa J, Ichinohe N, Ohsawa S, Kaneko T, Rockland KS, Yamamori T. Area-specific substratification of deep layer neurons in the rat cortex. J Comp Neurol 2013; 520:3553-73. [PMID: 22678985 DOI: 10.1002/cne.23160] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Gene markers are useful tools to identify cell types for fine mapping of neuronal circuits. Here we report area-specific sublamina structure of the rat cerebral cortex using cholecystokinin (cck) and purkinje cell protein4 (pcp4) mRNAs as the markers for excitatory neuron subtypes in layers 5 and 6. We found a segregated expression, especially pronounced in layer 6, where corticothalamic and corticocortical projecting neurons reside. To examine the relationship between gene expression and projection target, we injected retrograde tracers into several thalamic subnuclei, ventral posterior (VP), posterior (PO), mediodorsal (MD), medial and lateral geniculate nuclei (MGN and LGN); as well as into two cortical areas (M1 and V1). This combination of tracer-in situ hybridization (ISH) experiments revealed that corticocortical neurons predominantly express cck and corticothalamic neurons predominantly express pcp4 mRNAs in all areas tested. In general, cck(+) and pcp4(+) cells occupied the upper and lower compartment of layer 6a, respectively. However, the sublaminar distribution and the relative abundance of cck(+) and pcp4(+) cells were quite distinctive across areas. For example, layer 6 of the prelimbic cortex was almost devoid of cck(+) neurons, and was occupied instead by corticothalamic pcp4(+) neurons. In the lateral areas, such as S2, there was an additional layer of cck(+) cells positioned below the pcp4(+) compartment. The claustrum, which has a tight relationship with the cortex, mostly consisted of cck(+)/pcp4(-) cells. In summary, the combination of gene markers and retrograde tracers revealed a distinct sublaminar organization, with conspicuous cross-area variation in the arrangement and relative density of corticothalamic connections.
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Affiliation(s)
- Akiya Watakabe
- Division of Brain Biology, National Institute for Basic Biology, Graduate University for Advanced Studies, Okazaki, Japan.
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85
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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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86
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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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87
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Ren A, Zhang H, Xie Z, Ma X, Ji W, He DZZ, Yuan W, Ding YQ, Zhang XH, Zhang WJ. Regulation of hippocampus-dependent memory by the zinc finger protein Zbtb20 in mature CA1 neurons. J Physiol 2012; 590:4917-32. [PMID: 22777671 DOI: 10.1113/jphysiol.2012.234187] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The mammalian hippocampus harbours neural circuitry that is crucial for associative learning and memory. The mechanisms that underlie the development and regulation of this complex circuitry are not fully understood. Our previous study established an essential role for the zinc finger protein Zbtb20 in the specification of CA1 field identity in the developing hippocampus. Here, we show that conditionally deleting Zbtb20 specifically in mature CA1 pyramidal neurons impaired hippocampus-dependent memory formation, without affecting hippocampal architecture or the survival, identity and basal excitatory synaptic activity of CA1 pyramidal neurons. We demonstrate that mature CA1-specific Zbtb20 knockout mice exhibited reductions in long-term potentiation (LTP) and NMDA receptor (NMDAR)-mediated excitatory post-synaptic currents. Furthermore, we show that activity-induced phosphorylation of ERK and CREB is impaired in the hippocampal CA1 of Zbtb20 mutant mice. Collectively, these results indicate that Zbtb20 in mature CA1 plays an important role in LTP and memory by regulating NMDAR activity, and activation of ERK and CREB.
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Affiliation(s)
- Anjing Ren
- Department of Pathophysiology, Second Military Medical University, Shanghai 200433, China
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88
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Stevenson EL, Caldwell HK. The vasopressin 1b receptor and the neural regulation of social behavior. Horm Behav 2012; 61:277-82. [PMID: 22178035 PMCID: PMC3310934 DOI: 10.1016/j.yhbeh.2011.11.009] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 11/25/2011] [Accepted: 11/28/2011] [Indexed: 12/24/2022]
Abstract
To date, much of the work in rodents implicating vasopressin (Avp) in the regulation of social behavior has focused on its action via the Avp 1a receptor (Avpr1a). However, there is mounting evidence that the Avp 1b receptor (Avpr1b) also plays a significant role in Avp's modulation of social behavior. The Avpr1b is heavily expressed on the anterior pituitary cortiocotrophs where it acts as an important modulator of the endocrine stress response. In the brain, the Avpr1b is prominent in the CA2 region of the hippocampus, but can also be found in areas such as the paraventricular nucleus of the hypothalamus and the olfactory bulb. Studies that have employed genetic knockouts or pharmacological manipulation of the Avpr1b point to the importance of central Avpr1b in the modulation of social behavior. However, there continues to be a knowledge gap in our understanding of where in the brain this is occurring, as well as how and if the central actions of Avp acting via the Avpr1b interact with the stress axis. In this review we focus on the genetic and pharmacological studies that have implicated the Avpr1b in the neural regulation of social behaviors, including social forms of aggressive behavior, social memory, and social motivation. This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior.
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Affiliation(s)
- Erica L Stevenson
- Laboratory of Neuroendocrinology and Behavior, Department of Biological Sciences and School of Biomedical Sciences, Kent State University, Kent, OH 44242,, USA
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89
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Shinohara Y, Hosoya A, Yahagi K, Ferecskó AS, Yaguchi K, Sík A, Itakura M, Takahashi M, Hirase H. Hippocampal CA3 and CA2 have distinct bilateral innervation patterns to CA1 in rodents. Eur J Neurosci 2012; 35:702-10. [DOI: 10.1111/j.1460-9568.2012.07993.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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90
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Piskorowski RA, Chevaleyre V. Synaptic integration by different dendritic compartments of hippocampal CA1 and CA2 pyramidal neurons. Cell Mol Life Sci 2012; 69:75-88. [PMID: 21796451 PMCID: PMC11115016 DOI: 10.1007/s00018-011-0769-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 06/13/2011] [Accepted: 07/05/2011] [Indexed: 01/18/2023]
Abstract
Pyramidal neurons have a complex dendritic arbor containing tens of thousands of synapses. In order for the somatic/axonal membrane potential to reach action potential threshold, concurrent activation of multiple excitatory synapses is required. Frequently, instead of a simple algebraic summation of synaptic potentials in the soma, different dendritic compartments contribute to the integration of multiple inputs, thus endowing the neuron with a powerful computational ability. Most pyramidal neurons share common functional properties. However, different and sometimes contrasting dendritic integration rules are also observed. In this review, we focus on the dendritic integration of two neighboring pyramidal neurons in the hippocampus: the well-characterized CA1 and the much less understood CA2. The available data reveal that the dendritic integration of these neurons is markedly different even though they are targeted by common inputs at similar locations along their dendrites. This contrasting dendritic integration results in different routing of information flow and generates different corticohippocampal loops.
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Affiliation(s)
- Rebecca A. Piskorowski
- Université Paris Descartes, Sorbonne Paris Cité, IFR 95, CNRS UMR8118, Equipe ATIP, 45 rue des Saints-Pères, 75006 Paris, France
| | - Vivien Chevaleyre
- Université Paris Descartes, Sorbonne Paris Cité, IFR 95, CNRS UMR8118, Equipe ATIP, 45 rue des Saints-Pères, 75006 Paris, France
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91
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Slomianka L, Amrein I, Knuesel I, Sørensen JC, Wolfer DP. Hippocampal pyramidal cells: the reemergence of cortical lamination. Brain Struct Funct 2011; 216:301-17. [PMID: 21597968 PMCID: PMC3197924 DOI: 10.1007/s00429-011-0322-0] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 04/26/2011] [Indexed: 12/16/2022]
Abstract
The increasing resolution of tract-tracing studies has led to the definition of segments along the transverse axis of the hippocampal pyramidal cell layer, which may represent functionally defined elements. This review will summarize evidence for a morphological and functional differentiation of pyramidal cells along the radial (deep to superficial) axis of the cell layer. In many species, deep and superficial sublayers can be identified histologically throughout large parts of the septotemporal extent of the hippocampus. Neurons in these sublayers are generated during different periods of development. During development, deep and superficial cells express genes (Sox5, SatB2) that also specify the phenotypes of superficial and deep cells in the neocortex. Deep and superficial cells differ neurochemically (e.g. calbindin and zinc) and in their adult gene expression patterns. These markers also distinguish sublayers in the septal hippocampus, where they are not readily apparent histologically in rat or mouse. Deep and superficial pyramidal cells differ in septal, striatal, and neocortical efferent connections. Distributions of deep and superficial pyramidal cell dendrites and studies in reeler or sparsely GFP-expressing mice indicate that this also applies to afferent pathways. Histological, neurochemical, and connective differences between deep and superficial neurons may correlate with (patho-) physiological phenomena specific to pyramidal cells at different radial locations. We feel that an appreciation of radial subdivisions in the pyramidal cell layer reminiscent of lamination in other cortical areas may be critical in the interpretation of studies of hippocampal anatomy and function.
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Affiliation(s)
- Lutz Slomianka
- Institute of Anatomy, University of Zürich, 8057 Zürich, Switzerland.
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92
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Updating hippocampal representations: CA2 joins the circuit. Trends Neurosci 2011; 34:526-35. [DOI: 10.1016/j.tins.2011.07.007] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 06/13/2011] [Accepted: 07/25/2011] [Indexed: 12/20/2022]
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93
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Vellano CP, Lee SE, Dudek SM, Hepler JR. RGS14 at the interface of hippocampal signaling and synaptic plasticity. Trends Pharmacol Sci 2011; 32:666-74. [PMID: 21906825 DOI: 10.1016/j.tips.2011.07.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 06/28/2011] [Accepted: 07/07/2011] [Indexed: 11/29/2022]
Abstract
Learning and memory are encoded within the brain as biochemical and physical changes at synapses that alter synaptic transmission, a process known as synaptic plasticity. Although much is known about factors that positively regulate synaptic plasticity, very little is known about factors that negatively regulate this process. Recently, the signaling protein RGS14 (Regulator of G protein Signaling 14) was identified as a natural suppressor of hippocampal-based learning and memory as well as synaptic plasticity within CA2 hippocampal neurons. RGS14 is a multifunctional scaffolding protein that integrates unconventional G protein and mitogen-activated protein (MAP) kinase signaling pathways that are themselves key regulators of synaptic plasticity, learning, and memory. Here, we highlight the known roles for RGS14 in brain physiology and unconventional G protein signaling pathways, and propose molecular models to describe how RGS14 may integrate these diverse signaling pathways to modulate synaptic plasticity in CA2 hippocampal neurons.
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Affiliation(s)
- Christopher P Vellano
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, Atlanta, GA 30322, USA.
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94
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Richards K, Watson C, Buckley RF, Kurniawan ND, Yang Z, Keller MD, Beare R, Bartlett PF, Egan GF, Galloway GJ, Paxinos G, Petrou S, Reutens DC. Segmentation of the mouse hippocampal formation in magnetic resonance images. Neuroimage 2011; 58:732-40. [PMID: 21704710 DOI: 10.1016/j.neuroimage.2011.06.025] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 05/29/2011] [Accepted: 06/09/2011] [Indexed: 10/18/2022] Open
Abstract
The hippocampal formation plays an important role in cognition, spatial navigation, learning, and memory. High resolution magnetic resonance (MR) imaging makes it possible to study in vivo changes in the hippocampus over time and is useful for comparing hippocampal volume and structure in wild type and mutant mice. Such comparisons demand a reliable way to segment the hippocampal formation. We have developed a method for the systematic segmentation of the hippocampal formation using the perfusion-fixed C57BL/6 mouse brain for application in longitudinal and comparative studies. Our aim was to develop a guide for segmenting over 40 structures in an adult mouse brain using 30 μm isotropic resolution images acquired with a 16.4 T MR imaging system and combined using super-resolution reconstruction.
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Affiliation(s)
- Kay Richards
- The Australian Mouse Brain Mapping Consortium, The University of Queensland, Queensland, Brisbane, Australia
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95
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Matà S, Ambrosini S, Mello T, Lolli F, Minciacchi D. Anti-myelin associated glycoprotein antibodies recognize HNK-1 epitope on CNS. J Neuroimmunol 2011; 236:99-105. [PMID: 21621858 DOI: 10.1016/j.jneuroim.2011.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2011] [Revised: 05/04/2011] [Accepted: 05/06/2011] [Indexed: 11/18/2022]
Abstract
Antibodies to myelin-associated glycoprotein (MAG) are associated with demyelinating polyneuropathy and are specific for the HNK-1 epitope. To test if anti-MAG IgM recognize HNK-1 on CNS, sera from 20 patients and 238 controls were tested on rat slices by indirect immunofluorescence (IIF). IgM from anti-MAG positive patients, but not from control sera, stained rat brain with perineuronal or neuropil pattern, depending on the CNS region. IIF titers significantly correlated with ELISA anti-MAG titers. The staining of patients' sera were inhibited by mouse anti-HNK-1 monoclonal antibody. Our results demonstrate that anti-MAG IgM recognizes HNK-1 outside the peripheral nerve myelin carriers.
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Affiliation(s)
- Sabrina Matà
- Department of Neurological and Psychiatric Sciences, University of Firenze, Italy.
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96
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Huang KP, Huang FL. Calcium-Sensitive Translocation of Calmodulin and Neurogranin between Soma and Dendrites of Mouse Hippocampal CA1 Neurons. ACS Chem Neurosci 2011; 2:223-230. [PMID: 21516261 PMCID: PMC3080107 DOI: 10.1021/cn200003f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Accepted: 02/22/2011] [Indexed: 12/14/2022] Open
Abstract
Calmodulin (CaM) and neurogranin (Ng) are two abundant neuronal proteins whose interactions are implicated in the regulation of synaptic responses and plasticity. We employed the "low-calcium" model of epilepsy in hippocampal slices to investigate the mobilization of these two proteins in CA1 pyramidal neurons. Perfusion of mouse hippocampal slices with Ca(2+)-free artificial CSF (ACSF) caused a suppression of synaptic transmission and generation of epileptic activity; these responses could be reversed by normal Ca(2+)-containing ACSF. Fluorescence immunochemical staining of control hippocampal slices bathed in normal ACSF revealed that CaM and Ng were more concentrated in soma than in dendrites; especially for CaM, it was concentrated in the nucleus. Perfusion of hippocampal slices with Ca(2+)-free ACSF caused translocation of these two proteins from soma to dendrites, and this trafficking was also reversed by Ca(2+)-containing buffer. A reduction of ∼15 and 40 nM intracellular Ca(2+), [Ca(2+)](i), caused half-maximum translocation of Ng and CaM, respectively. Hippocampal CA1 pyramidal neurons were the most responsive to this Ca(2+)-sensitive translocation as compared to those from other areas of the hippocampus. These results illustrated the unique feature of hippocampal CA1 pyramidal neurons in sequestering high concentrations of CaM and Ng in soma and releasing them to distal dendrites at reducing level of [Ca(2+)](i).
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Affiliation(s)
- Kuo-Ping Huang
- Program of Developmental Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Freesia L. Huang
- Program of Developmental Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, United States
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97
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Kjonigsen LJ, Leergaard TB, Witter MP, Bjaalie JG. Digital atlas of anatomical subdivisions and boundaries of the rat hippocampal region. Front Neuroinform 2011; 5:2. [PMID: 21519393 PMCID: PMC3078752 DOI: 10.3389/fninf.2011.00002] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 03/26/2011] [Indexed: 11/30/2022] Open
Abstract
The rat hippocampal region is frequently studied in relation to learning and memory processes and brain diseases. The region is complex, consisting of multiple subdivisions that are challenging to delineate anatomically. Published atlases of the rat brain typically lack the underlying histological criteria necessary to identify boundaries, and textbooks descriptions of the region are often inadequately illustrated and thus difficult to relate to experimental data. An overview of both anatomical features and criteria used to delineate boundaries is required to assign location to experimental material from the hippocampal region. To address this issue, we have developed a web-based atlas application in which images of histological sections are integrated with new and up-to-date criteria for subdividing the rat hippocampus formation, fasciola, and associated parahippocampal regions. The atlas application consists of an interactive image viewer with high-resolution images of an extensive series of sections stained for NeuN, calbindin, and parvalbumin, and an index of structures with detailed descriptions of the criteria used to define the boundaries. Images can be inspected with a graphical overlay of selected subregions. Bi-directional links between images and the index of structures are provided. In summary, we provide a novel content-rich digital atlas resource facilitating identification of morphological features relevant for delineating the anatomical subdivisions of the rat hippocampal region. The atlas application is available at http://www.rbwb.org.
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Affiliation(s)
- Lisa J Kjonigsen
- Centre for Molecular Biology and Neuroscience, Institute of Basic Medical Sciences, University of Oslo Oslo, Norway
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98
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Perrin RJ, Craig-Schapiro R, Malone JP, Shah AR, Gilmore P, Davis AE, Roe CM, Peskind ER, Li G, Galasko DR, Clark CM, Quinn JF, Kaye JA, Morris JC, Holtzman DM, Townsend RR, Fagan AM. Identification and validation of novel cerebrospinal fluid biomarkers for staging early Alzheimer's disease. PLoS One 2011; 6:e16032. [PMID: 21264269 PMCID: PMC3020224 DOI: 10.1371/journal.pone.0016032] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 12/03/2010] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Ideally, disease modifying therapies for Alzheimer disease (AD) will be applied during the 'preclinical' stage (pathology present with cognition intact) before severe neuronal damage occurs, or upon recognizing very mild cognitive impairment. Developing and judiciously administering such therapies will require biomarker panels to identify early AD pathology, classify disease stage, monitor pathological progression, and predict cognitive decline. To discover such biomarkers, we measured AD-associated changes in the cerebrospinal fluid (CSF) proteome. METHODS AND FINDINGS CSF samples from individuals with mild AD (Clinical Dementia Rating [CDR] 1) (n = 24) and cognitively normal controls (CDR 0) (n = 24) were subjected to two-dimensional difference-in-gel electrophoresis. Within 119 differentially-abundant gel features, mass spectrometry (LC-MS/MS) identified 47 proteins. For validation, eleven proteins were re-evaluated by enzyme-linked immunosorbent assays (ELISA). Six of these assays (NrCAM, YKL-40, chromogranin A, carnosinase I, transthyretin, cystatin C) distinguished CDR 1 and CDR 0 groups and were subsequently applied (with tau, p-tau181 and Aβ42 ELISAs) to a larger independent cohort (n = 292) that included individuals with very mild dementia (CDR 0.5). Receiver-operating characteristic curve analyses using stepwise logistic regression yielded optimal biomarker combinations to distinguish CDR 0 from CDR>0 (tau, YKL-40, NrCAM) and CDR 1 from CDR<1 (tau, chromogranin A, carnosinase I) with areas under the curve of 0.90 (0.85-0.94 95% confidence interval [CI]) and 0.88 (0.81-0.94 CI), respectively. CONCLUSIONS Four novel CSF biomarkers for AD (NrCAM, YKL-40, chromogranin A, carnosinase I) can improve the diagnostic accuracy of Aβ42 and tau. Together, these six markers describe six clinicopathological stages from cognitive normalcy to mild dementia, including stages defined by increased risk of cognitive decline. Such a panel might improve clinical trial efficiency by guiding subject enrollment and monitoring disease progression. Further studies will be required to validate this panel and evaluate its potential for distinguishing AD from other dementing conditions.
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Affiliation(s)
- Richard J Perrin
- Division of Neuropathology, Washington University School of Medicine, St. Louis, Missouri, United States of America.
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99
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Guerreiro-Diniz C, de Melo Paz RB, Hamad MHS, Filho CS, Martins AAV, Neves HB, de Souza Cunha ED, Alves GC, de Sousa LA, Dias IA, Trévia N, de Sousa AA, Passos A, Lins N, Torres Neto JB, da Costa Vasconcelos PF, Picanço-Diniz CW. Hippocampus and dentate gyrus of the Cebus monkey: Architectonic and stereological study. J Chem Neuroanat 2010; 40:148-59. [DOI: 10.1016/j.jchemneu.2010.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 06/06/2010] [Accepted: 06/07/2010] [Indexed: 01/26/2023]
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100
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Mercer A, Eastlake K, Trigg HL, Thomson AM. Local circuitry involving parvalbumin-positive basket cells in the CA2 region of the hippocampus. Hippocampus 2010; 22:43-56. [PMID: 20882544 DOI: 10.1002/hipo.20841] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2010] [Indexed: 11/07/2022]
Abstract
There is a growing recognition that the CA2 region of the hippocampus has its own distinctive properties, inputs, and pathologies. The dendritic and axonal patterns of some interneurons in this region are also strikingly different from those described previously in CA1 and CA3. The local circuitry in this region, however, had yet to be studied in detail. Accordingly, using dual intracellular recordings and biocytin-filling, excitatory and inhibitory connections involving CA2 parvalbumin-positive basket cells were characterized for the first time. CA2 basket cells targeted neighboring pyramidal cells and received excitatory inputs from them. CA2 basket cells that resembled those in CA1 with a fast spiking behavior and dendritic tree confined to the region of origin received depressing excitatory postsynaptic potentials (EPSPs). In contrast, unlike CA1 basket cells but like CA1 Oriens-Lacunosum Moleculare (OLM) cells, the majority of CA2 basket cells had horizontally oriented dendrites in Stratum Oriens (SO), which extended into all three CA subfields, had an adapting firing pattern, presented a "sag" in their voltage responses to hyperpolarizing current injection, and received facilitating EPSPs. The expression of I(h) did not influence the EPSP time courses and paired pulse ratios (PPR). Estimates of the probability of release (p) for the depressing and facilitating EPSPs were correlated with the PPR. Connections with low probabilities of release had higher PPR. Quantal amplitude (q) for the facilitating connections was larger than q at depressing inputs onto fast spiking basket cells.
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Affiliation(s)
- Audrey Mercer
- Department of Pharmacology, School of Pharmacy, University of London, London WC1N 1AX, United Kingdom.
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