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Pfitzer J, Pinky PD, Perman S, Redmon E, Cmelak L, Suppiramaniam V, Coric V, Qureshi IA, Gramlich MW, Reed MN. Troriluzole rescues glutamatergic deficits, amyloid and tau pathology, and synaptic and memory impairments in 3xTg-AD mice. J Neurochem 2024. [PMID: 39214859 DOI: 10.1111/jnc.16215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Revised: 07/18/2024] [Accepted: 08/15/2024] [Indexed: 09/04/2024]
Abstract
Alzheimer's disease (AD) is a neurodegenerative condition in which clinical symptoms are highly correlated with the loss of glutamatergic synapses. While later stages of AD are associated with markedly decreased glutamate levels due to neuronal loss, in the early stages, pathological accumulation of glutamate and hyperactivity contribute to AD pathology and cognitive dysfunction. There is increasing awareness that presynaptic dysfunction, particularly synaptic vesicle (SV) alterations, play a key role in mediating this early-stage hyperactivity. In the current study, we sought to determine whether the 3xTg mouse model of AD that exhibits both beta-amyloid (Aβ) and tau-related pathology would exhibit similar presynaptic changes as previously observed in amyloid or tau models separately. Hippocampal cultures from 3xTg mice were used to determine whether presynaptic vesicular glutamate transporters (VGlut) and glutamate are increased at the synaptic level while controlling for postsynaptic activity. We observed that 3xTg hippocampal cultures exhibited increased VGlut1 associated with an increase in glutamate release, similar to prior observations in cultures from tau mouse models. However, the SV pool size was also increased in 3xTg cultures, an effect not previously observed in tau mouse models but observed in Aβ models, suggesting the changes in pool size may be due to Aβ and not tau. Second, we sought to determine whether treatment with troriluzole, a novel 3rd generation tripeptide prodrug of the glutamate modulator riluzole, could reduce VGlut1 and glutamate release to restore cognitive deficits in 8-month-old 3xTg mice. Treatment with troriluzole reduced VGlut1 expression, decreased basal and evoked glutamate release, and restored cognitive deficits in 3xTg mice. Together, these findings suggest presynaptic alterations are early events in AD that represent potential targets for therapeutic intervention, and these results support the promise of glutamate-modulating drugs such as troriluzole in Alzheimer's disease.
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Affiliation(s)
- Jeremiah Pfitzer
- Department of Drug Discovery and Development, Auburn University, Auburn, Alabama, USA
| | - Priyanka D Pinky
- Department of Drug Discovery and Development, Auburn University, Auburn, Alabama, USA
| | - Savannah Perman
- Department of Drug Discovery and Development, Auburn University, Auburn, Alabama, USA
| | - Emma Redmon
- Department of Drug Discovery and Development, Auburn University, Auburn, Alabama, USA
| | - Luca Cmelak
- Department of Psychological Sciences, Auburn University, Auburn, Alabama, USA
| | - Vishnu Suppiramaniam
- Department of Drug Discovery and Development, Auburn University, Auburn, Alabama, USA
- Center for Neuroscience Initiative, Auburn University, Auburn, Alabama, USA
- Department of Molecular and Cellular Biology, College of Science and Mathematics, Kennesaw State University, Kennesaw, Georgia, USA
| | - Vladimir Coric
- Biohaven Pharmaceuticals Inc., New Haven, Connecticut, USA
| | | | - Michael W Gramlich
- Center for Neuroscience Initiative, Auburn University, Auburn, Alabama, USA
- Department of Physics, Auburn University, Auburn, Alabama, USA
| | - Miranda N Reed
- Department of Drug Discovery and Development, Auburn University, Auburn, Alabama, USA
- Center for Neuroscience Initiative, Auburn University, Auburn, Alabama, USA
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Zouridis IS, Balsamo G, Preston-Ferrer P, Burgalossi A. Anatomical and electrophysiological analysis of the fasciola cinerea of the mouse hippocampus. Hippocampus 2024. [PMID: 39105449 DOI: 10.1002/hipo.23623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 05/20/2024] [Accepted: 07/03/2024] [Indexed: 08/07/2024]
Abstract
The hippocampus is considered essential for several forms of declarative memory, including spatial and social memory. Despite the extensive research of the classic subfields of the hippocampus, the fasciola cinerea (FC)-a medially located structure within the hippocampal formation-has remained largely unexplored. In the present study, we performed a morpho-functional characterization of principal neurons in the mouse FC. Using in vivo juxtacellular recording of single neurons, we found that FC neurons are distinct from neighboring CA1 pyramidal cells, both morphologically and electrophysiologically. Specifically, FC neurons displayed non-pyramidal morphology and granule cell-like apical dendrites. Compared to neighboring CA1 pyramidal neurons, FC neurons exhibited more regular in vivo firing patterns and a lower tendency to fire spikes at short interspike intervals. Furthermore, tracing experiments revealed that the FC receives inputs from the lateral but not the medial entorhinal cortex and CA3, and it provides a major intra-hippocampal projection to the septal CA2 and sparser inputs to the distal CA1. Overall, our results indicate that the FC is a morphologically and electrophysiologically distinct subfield of the hippocampal formation; given the established role of CA2 in social memory and seizure initiation, the unique efferent intra-hippocampal connectivity of the FC points to possible roles in social cognition and temporal lobe epilepsy.
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Affiliation(s)
- Ioannis S Zouridis
- Institute of Neurobiology, Eberhard Karls University of Tübingen, Tübingen, Germany
- Werner-Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- Graduate Training Centre of Neuroscience-International Max-Planck Research School (IMPRS), Tübingen, Germany
| | - Giuseppe Balsamo
- Institute of Neurobiology, Eberhard Karls University of Tübingen, Tübingen, Germany
- Werner-Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- Graduate Training Centre of Neuroscience-International Max-Planck Research School (IMPRS), Tübingen, Germany
| | - Patricia Preston-Ferrer
- Institute of Neurobiology, Eberhard Karls University of Tübingen, Tübingen, Germany
- Werner-Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Andrea Burgalossi
- Institute of Neurobiology, Eberhard Karls University of Tübingen, Tübingen, Germany
- Werner-Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
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Ohara S, Rannap M, Tsutsui KI, Draguhn A, Egorov AV, Witter MP. Hippocampal-medial entorhinal circuit is differently organized along the dorsoventral axis in rodents. Cell Rep 2023; 42:112001. [PMID: 36680772 DOI: 10.1016/j.celrep.2023.112001] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 10/14/2022] [Accepted: 12/31/2022] [Indexed: 01/21/2023] Open
Abstract
The general understanding of hippocampal circuits is that the hippocampus and the entorhinal cortex (EC) are topographically connected through parallel identical circuits along the dorsoventral axis. Our anterograde tracing and in vitro electrophysiology data, however, show a markedly different dorsoventral organization of the hippocampal projection to the medial EC (MEC). While dorsal hippocampal projections are confined to the dorsal MEC, ventral hippocampal projections innervate both dorsal and ventral MEC. Further, whereas the dorsal hippocampus preferentially targets layer Vb (LVb) neurons, the ventral hippocampus mainly targets cells in layer Va (LVa). This connectivity scheme differs from hippocampal projections to the lateral EC, which are topographically organized along the dorsoventral axis. As LVa neurons project to telencephalic structures, our findings indicate that the ventral hippocampus regulates LVa-mediated entorhinal-neocortical output from both dorsal and ventral MEC. Overall, the marked dorsoventral differences in hippocampal-entorhinal connectivity impose important constraints on signal flow in hippocampal-neocortical circuits.
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Affiliation(s)
- Shinya Ohara
- Laboratory of Systems Neuroscience, Tohoku University Graduate School of Life Sciences, Sendai, Japan; Kavli Institute for Systems Neuroscience, Center for Computational Neuroscience, Egil and Pauline Braathen and Fred Kavli Center for Cortical Microcircuits, NTNU Norwegian University of Science and Technology, Trondheim, Norway; PRESTO, Japan Science and Technology Agency (JST), Tokyo, Japan
| | - Märt Rannap
- Institute of Physiology and Pathophysiology, Medical Faculty, Heidelberg University, Heidelberg, Germany
| | - Ken-Ichiro Tsutsui
- Laboratory of Systems Neuroscience, Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | - Andreas Draguhn
- Institute of Physiology and Pathophysiology, Medical Faculty, Heidelberg University, Heidelberg, Germany
| | - Alexei V Egorov
- Institute of Physiology and Pathophysiology, Medical Faculty, Heidelberg University, Heidelberg, Germany.
| | - Menno P Witter
- Kavli Institute for Systems Neuroscience, Center for Computational Neuroscience, Egil and Pauline Braathen and Fred Kavli Center for Cortical Microcircuits, NTNU Norwegian University of Science and Technology, Trondheim, Norway.
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Structural and Functional Deviations of the Hippocampus in Schizophrenia and Schizophrenia Animal Models. Int J Mol Sci 2022; 23:ijms23105482. [PMID: 35628292 PMCID: PMC9143100 DOI: 10.3390/ijms23105482] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/09/2022] [Accepted: 05/11/2022] [Indexed: 01/04/2023] Open
Abstract
Schizophrenia is a grave neuropsychiatric disease which frequently onsets between the end of adolescence and the beginning of adulthood. It is characterized by a variety of neuropsychiatric abnormalities which are categorized into positive, negative and cognitive symptoms. Most therapeutical strategies address the positive symptoms by antagonizing D2-dopamine-receptors (DR). However, negative and cognitive symptoms persist and highly impair the life quality of patients due to their disabling effects. Interestingly, hippocampal deviations are a hallmark of schizophrenia and can be observed in early as well as advanced phases of the disease progression. These alterations are commonly accompanied by a rise in neuronal activity. Therefore, hippocampal formation plays an important role in the manifestation of schizophrenia. Furthermore, studies with animal models revealed a link between environmental risk factors and morphological as well as electrophysiological abnormalities in the hippocampus. Here, we review recent findings on structural and functional hippocampal abnormalities in schizophrenic patients and in schizophrenia animal models, and we give an overview on current experimental approaches that especially target the hippocampus. A better understanding of hippocampal aberrations in schizophrenia might clarify their impact on the manifestation and on the outcome of this severe disease.
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Meier AM, Wang Q, Ji W, Ganachaud J, Burkhalter A. Modular Network between Postrhinal Visual Cortex, Amygdala, and Entorhinal Cortex. J Neurosci 2021; 41:4809-4825. [PMID: 33849948 PMCID: PMC8260166 DOI: 10.1523/jneurosci.2185-20.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 04/02/2021] [Accepted: 04/07/2021] [Indexed: 11/21/2022] Open
Abstract
The postrhinal area (POR) is a known center for integrating spatial with nonspatial visual information and a possible hub for influencing landmark navigation by affective input from the amygdala. This may involve specific circuits within muscarinic acetylcholine receptor 2 (M2)-positive (M2+) or M2- modules of POR that associate inputs from the thalamus, cortex, and amygdala, and send outputs to the entorhinal cortex. Using anterograde and retrograde labeling with conventional and viral tracers in male and female mice, we found that all higher visual areas of the ventral cortical stream project to the amygdala, while such inputs are absent from primary visual cortex and dorsal stream areas. Unexpectedly for the presumed salt-and-pepper organization of mouse extrastriate cortex, tracing results show that inputs from the dorsal lateral geniculate nucleus and lateral posterior nucleus were spatially clustered in layer 1 (L1) and overlapped with M2+ patches of POR. In contrast, input from the amygdala to L1 of POR terminated in M2- interpatches. Importantly, the amygdalocortical input to M2- interpatches in L1 overlapped preferentially with spatially clustered apical dendrites of POR neurons projecting to amygdala and entorhinal area lateral, medial (ENTm). The results suggest that subnetworks in POR, used to build spatial maps for navigation, do not receive direct thalamocortical M2+ patch-targeting inputs. Instead, they involve local networks of M2- interpatches, which are influenced by affective information from the amygdala and project to ENTm, whose cells respond to visual landmark cues for navigation.SIGNIFICANCE STATEMENT A central purpose of visual object recognition is identifying the salience of objects and approaching or avoiding them. However, it is not currently known how the visual cortex integrates the multiple streams of information, including affective and navigational cues, which are required to accomplish this task. We find that in a higher visual area, the postrhinal cortex, the cortical sheet is divided into interdigitating modules receiving distinct inputs from visual and emotion-related sources. One of these modules is preferentially connected with the amygdala and provides outputs to entorhinal cortex, constituting a processing stream that may assign emotional salience to objects and landmarks for the guidance of goal-directed navigation.
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Affiliation(s)
- Andrew M Meier
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
| | - Quanxin Wang
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
| | - Weiqing Ji
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
| | - Jehan Ganachaud
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
| | - Andreas Burkhalter
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110
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Rapid brain structure and tumour margin detection on whole frozen tissue sections by fast multiphotometric mid-infrared scanning. Sci Rep 2021; 11:11307. [PMID: 34050224 PMCID: PMC8163866 DOI: 10.1038/s41598-021-90777-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 05/17/2021] [Indexed: 01/31/2023] Open
Abstract
Frozen section analysis is a frequently used method for examination of tissue samples, especially for tumour detection. In the majority of cases, the aim is to identify characteristic tissue morphologies or tumour margins. Depending on the type of tissue, a high number of misdiagnoses are associated with this process. In this work, a fast spectroscopic measurement device and workflow was developed that significantly improves the speed of whole frozen tissue section analyses and provides sufficient information to visualize tissue structures and tumour margins, dependent on their lipid and protein molecular vibrations. That optical and non-destructive method is based on selected wavenumbers in the mid-infrared (MIR) range. We present a measuring system that substantially outperforms a commercially available Fourier Transform Infrared (FT-IR) Imaging system, since it enables acquisition of reduced spectral information at a scan field of 1 cm2 in 3 s, with a spatial resolution of 20 µm. This allows fast visualization of segmented structure areas with little computational effort. For the first time, this multiphotometric MIR system is applied to biomedical tissue sections. We are referencing our novel MIR scanner on cryopreserved murine sagittal and coronal brain sections, especially focusing on the hippocampus, and show its usability for rapid identification of primary hepatocellular carcinoma (HCC) in mouse liver.
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Hahn JD, Swanson LW, Bowman I, Foster NN, Zingg B, Bienkowski MS, Hintiryan H, Dong HW. An open access mouse brain flatmap and upgraded rat and human brain flatmaps based on current reference atlases. J Comp Neurol 2020; 529:576-594. [PMID: 32511750 DOI: 10.1002/cne.24966] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 12/11/2022]
Abstract
Here we present a flatmap of the mouse central nervous system (CNS) (brain) and substantially enhanced flatmaps of the rat and human brain. Also included are enhanced representations of nervous system white matter tracts, ganglia, and nerves, and an enhanced series of 10 flatmaps showing different stages of rat brain development. The adult mouse and rat brain flatmaps provide layered diagrammatic representation of CNS divisions, according to their arrangement in corresponding reference atlases: Brain Maps 4.0 (BM4, rat) (Swanson, The Journal of Comparative Neurology, 2018, 526, 935-943), and the first version of the Allen Reference Atlas (mouse) (Dong, The Allen reference atlas, (book + CD-ROM): A digital color brain atlas of the C57BL/6J male mouse, 2007). To facilitate comparative analysis, both flatmaps are scaled equally, and the divisional hierarchy of gray matter follows a topographic arrangement used in BM4. Also included with the mouse and rat brain flatmaps are cerebral cortex atlas level contours based on the reference atlases, and direct graphical and tabular comparison of regional parcellation. To encourage use of the brain flatmaps, they were designed and organized, with supporting reference tables, for ease-of-use and to be amenable to computational applications. We demonstrate how they can be adapted to represent novel parcellations resulting from experimental data, and we provide a proof-of-concept for how they could form the basis of a web-based graphical data viewer and analysis platform. The mouse, rat, and human brain flatmap vector graphics files (Adobe Reader/Acrobat viewable and Adobe Illustrator editable) and supporting tables are provided open access; they constitute a broadly applicable neuroscience toolbox resource for researchers seeking to map and perform comparative analysis of brain data.
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Affiliation(s)
- Joel D Hahn
- Department of Biological Sciences, University of Southern California, California, Los Angeles, USA.,Center for Integrated Connectomics (CIC), Keck School of Medicine of University of Southern California, University of Southern California Stevens Neuroimaging and Informatics Institute, Los Angeles, California, USA
| | - Larry W Swanson
- Department of Biological Sciences, University of Southern California, California, Los Angeles, USA
| | - Ian Bowman
- Center for Integrated Connectomics (CIC), Keck School of Medicine of University of Southern California, University of Southern California Stevens Neuroimaging and Informatics Institute, Los Angeles, California, USA
| | - Nicholas N Foster
- Center for Integrated Connectomics (CIC), Keck School of Medicine of University of Southern California, University of Southern California Stevens Neuroimaging and Informatics Institute, Los Angeles, California, USA
| | - Brian Zingg
- Center for Integrated Connectomics (CIC), Keck School of Medicine of University of Southern California, University of Southern California Stevens Neuroimaging and Informatics Institute, Los Angeles, California, USA
| | - Michael S Bienkowski
- Center for Integrated Connectomics (CIC), Keck School of Medicine of University of Southern California, University of Southern California Stevens Neuroimaging and Informatics Institute, Los Angeles, California, USA
| | - Houri Hintiryan
- Center for Integrated Connectomics (CIC), Keck School of Medicine of University of Southern California, University of Southern California Stevens Neuroimaging and Informatics Institute, Los Angeles, California, USA
| | - Hong-Wei Dong
- Center for Integrated Connectomics (CIC), Keck School of Medicine of University of Southern California, University of Southern California Stevens Neuroimaging and Informatics Institute, Los Angeles, California, USA.,Department of Neurology, Keck School of Medicine of University of Southern California, Los Angeles, California, USA.,Department of Physiology and Neuroscience, and Zilkha Neurogenetic Institute, Keck School of Medicine of University of Southern California, Los Angeles, California, USA
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Structural Correlates of CA2 and CA3 Pyramidal Cell Activity in Freely-Moving Mice. J Neurosci 2020; 40:5797-5806. [PMID: 32554511 DOI: 10.1523/jneurosci.0099-20.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 05/03/2020] [Accepted: 05/05/2020] [Indexed: 12/19/2022] Open
Abstract
Plasticity within hippocampal circuits is essential for memory functions. The hippocampal CA2/CA3 region is thought to be able to rapidly store incoming information by plastic modifications of synaptic weights within its recurrent network. High-frequency spike-bursts are believed to be essential for this process, by serving as triggers for synaptic plasticity. Given the diversity of CA2/CA3 pyramidal neurons, it is currently unknown whether and how burst activity, assessed in vivo during natural behavior, relates to principal cell heterogeneity. To explore this issue, we juxtacellularly recorded the activity of single CA2/CA3 neurons from freely-moving male mice, exploring a familiar environment. In line with previous work, we found that spatial and temporal activity patterns of pyramidal neurons correlated with their topographical position. Morphometric analysis revealed that neurons with a higher proportion of distal dendritic length displayed a higher tendency to fire spike-bursts. We propose that the dendritic architecture of pyramidal neurons might determine burst-firing by setting the relative amount of distal excitatory inputs from the entorhinal cortex.SIGNIFICANCE STATEMENT High-frequency spike-bursts are thought to serve fundamental computational roles within neural circuits. Within hippocampal circuits, spike-bursts are believed to serve as potent instructive signals, which increase the efficiency of information transfer and induce rapid modifications of synaptic efficacies. In the present study, by juxtacellularly recording and labeling single CA2/CA3 neurons in freely-moving mice, we explored whether and how burst propensity relates to pyramidal cell heterogeneity. We provide evidence that, within the CA2/CA3 region, neurons with higher proportion of distal dendritic length display a higher tendency to fire spike-bursts. Thus, the relative amount of entorhinal inputs, arriving onto the distal dendrites, might determine the burst propensity of individual CA2/CA3 neurons in vivo during natural behavior.
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