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Morgan GR, Carlyle BC. Interrogation of the human cortical peptidome uncovers cell-type specific signatures of cognitive resilience against Alzheimer's disease. Sci Rep 2024; 14:7161. [PMID: 38531951 DOI: 10.1038/s41598-024-57104-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 03/14/2024] [Indexed: 03/28/2024] Open
Abstract
Alzheimer's disease (AD) is characterised by age-related cognitive decline. Brain accumulation of amyloid-β plaques and tau tangles is required for a neuropathological AD diagnosis, yet up to one-third of AD-pathology positive community-dwelling elderly adults experience no symptoms of cognitive decline during life. Conversely, some exhibit chronic cognitive impairment in absence of measurable neuropathology, prompting interest into cognitive resilience-retained cognition despite significant neuropathology-and cognitive frailty-impaired cognition despite low neuropathology. Synapse loss is widespread within the AD-dementia, but not AD-resilient, brain. Recent evidence points towards critical roles for synaptic proteins, such as neurosecretory VGF, in cognitive resilience. However, VGF and related proteins often signal as peptide derivatives. Here, nontryptic peptidomic mass spectrometry was performed on 102 post-mortem cortical samples from individuals across cognitive and neuropathological spectra. Neuropeptide signalling proteoforms derived from VGF, somatostatin (SST) and protachykinin-1 (TAC1) showed higher abundance in AD-resilient than AD-dementia brain, whereas signalling proteoforms of cholecystokinin (CCK) and chromogranin (CHG) A/B and multiple cytoskeletal molecules were enriched in frail vs control brain. Integrating our data with publicly available single nuclear RNA sequencing (snRNA-seq) showed enrichment of cognition-related genes in defined cell-types with established links to cognitive resilience, including SST interneurons and excitatory intratelencephalic cells.
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Affiliation(s)
- G R Morgan
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, OX1 3QU, UK
| | - B C Carlyle
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, OX1 3QU, UK.
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford, OX1 3QU, UK.
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2
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Rybnicek J, Chen Y, Milic M, Tio ES, McLaurin J, Hohman TJ, De Jager PL, Schneider JA, Wang Y, Bennett DA, Tripathy S, Felsky D, Lambe EK. CHRNA5 links chandelier cells to severity of amyloid pathology in aging and Alzheimer's disease. Transl Psychiatry 2024; 14:83. [PMID: 38331937 PMCID: PMC10853183 DOI: 10.1038/s41398-024-02785-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/09/2024] [Accepted: 01/16/2024] [Indexed: 02/10/2024] Open
Abstract
Changes in high-affinity nicotinic acetylcholine receptors are intricately connected to neuropathology in Alzheimer's Disease (AD). Protective and cognitive-enhancing roles for the nicotinic α5 subunit have been identified, but this gene has not been closely examined in the context of human aging and dementia. Therefore, we investigate the nicotinic α5 gene CHRNA5 and the impact of relevant single nucleotide polymorphisms (SNPs) in prefrontal cortex from 922 individuals with matched genotypic and post-mortem RNA sequencing in the Religious Orders Study and Memory and Aging Project (ROS/MAP). We find that a genotype robustly linked to increased expression of CHRNA5 (rs1979905A2) predicts significantly reduced cortical β-amyloid load. Intriguingly, co-expression analysis suggests CHRNA5 has a distinct cellular expression profile compared to other nicotinic receptor genes. Consistent with this prediction, single nucleus RNA sequencing from 22 individuals reveals CHRNA5 expression is disproportionately elevated in chandelier neurons, a distinct subtype of inhibitory neuron known for its role in excitatory/inhibitory (E/I) balance. We show that chandelier neurons are enriched in amyloid-binding proteins compared to basket cells, the other major subtype of PVALB-positive interneurons. Consistent with the hypothesis that nicotinic receptors in chandelier cells normally protect against β-amyloid, cell-type proportion analysis from 549 individuals reveals these neurons show amyloid-associated vulnerability only in individuals with impaired function/trafficking of nicotinic α5-containing receptors due to homozygosity of the missense CHRNA5 SNP (rs16969968A2). Taken together, these findings suggest that CHRNA5 and its nicotinic α5 subunit exert a neuroprotective role in aging and Alzheimer's disease centered on chandelier interneurons.
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Affiliation(s)
- Jonas Rybnicek
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Yuxiao Chen
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Milos Milic
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Earvin S Tio
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - JoAnne McLaurin
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Timothy J Hohman
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Philip L De Jager
- Center for Translational & Computational Neuroimmunology, Department of Neurology and the Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York, NY, USA
| | - Julie A Schneider
- Department of Pathology, Rush University, Chicago, IL, USA
- Department of Neurological Sciences, Rush University, Chicago, IL, USA
| | - Yanling Wang
- Department of Neurological Sciences, Rush University, Chicago, IL, USA
| | - David A Bennett
- Department of Neurological Sciences, Rush University, Chicago, IL, USA
| | - Shreejoy Tripathy
- Department of Physiology, University of Toronto, Toronto, ON, Canada.
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada.
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
| | - Daniel Felsky
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada.
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
| | - Evelyn K Lambe
- Department of Physiology, University of Toronto, Toronto, ON, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
- Department of OBGYN, University of Toronto, Toronto, ON, Canada.
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3
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Nagarajan R, Lyu J, Kambali M, Wang M, Courtney CD, Christian-Hinman CA, Rudolph U. Genetic Ablation of Dentate Hilar Somatostatin-Positive GABAergic Interneurons is Sufficient to Induce Cognitive Impairment. Mol Neurobiol 2024; 61:567-580. [PMID: 37642935 DOI: 10.1007/s12035-023-03586-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/15/2023] [Indexed: 08/31/2023]
Abstract
Aging is often associated with a decline in cognitive function. A reduction in the number of somatostatin-positive (SOM+) interneurons in the dentate gyrus (DG) has been described in cognitively impaired but not in unimpaired aged rodents. However, it remains unclear whether the reduction in SOM + interneurons in the DG hilus is causal for age-related cognitive dysfunction. We hypothesized that hilar SOM+ interneurons play an essential role in maintaining cognitive function and that a reduction in the number of hilar SOM + interneurons might be sufficient to induce cognitive dysfunction. Hilar SOM+ interneurons were ablated by expressing a diphtheria toxin transgene specifically in these interneurons, which resulted in a reduction in the number of SOM+ /GAD-67+ neurons and dendritic spine density in the DG. C-fos and Iba-1 immunostainings were increased in DG and CA3, but not CA1, and BDNF protein expression in the hippocampus was decreased. Behavioral testing showed a reduced recognition index in the novel object recognition test, decreased alternations in the Y maze test, and longer latencies and path lengths in the learning and reversal learning phases of the Morris water maze. Our results show that partial genetic ablation of SOM+ hilar interneurons is sufficient to increase activity in DG and CA3, as has been described to occur with aging and to induce an impairment of learning and memory functions. Thus, partial ablation of hilar SOM + interneurons may be a significant contributing factor to age-related cognitive dysfunction. These mice may also be useful as a cellularly defined model of hippocampal aging.
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Affiliation(s)
- Rajasekar Nagarajan
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jinrui Lyu
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Maltesh Kambali
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Muxiao Wang
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Connor D Courtney
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Catherine A Christian-Hinman
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Uwe Rudolph
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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Hernández-Frausto M, Bilash OM, Masurkar AV, Basu J. Local and long-range GABAergic circuits in hippocampal area CA1 and their link to Alzheimer's disease. Front Neural Circuits 2023; 17:1223891. [PMID: 37841892 PMCID: PMC10570439 DOI: 10.3389/fncir.2023.1223891] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 09/08/2023] [Indexed: 10/17/2023] Open
Abstract
GABAergic inhibitory neurons are the principal source of inhibition in the brain. Traditionally, their role in maintaining the balance of excitation-inhibition has been emphasized. Beyond homeostatic functions, recent circuit mapping and functional manipulation studies have revealed a wide range of specific roles that GABAergic circuits play in dynamically tilting excitation-inhibition coupling across spatio-temporal scales. These span from gating of compartment- and input-specific signaling, gain modulation, shaping input-output functions and synaptic plasticity, to generating signal-to-noise contrast, defining temporal windows for integration and rate codes, as well as organizing neural assemblies, and coordinating inter-regional synchrony. GABAergic circuits are thus instrumental in controlling single-neuron computations and behaviorally-linked network activity. The activity dependent modulation of sensory and mnemonic information processing by GABAergic circuits is pivotal for the formation and maintenance of episodic memories in the hippocampus. Here, we present an overview of the local and long-range GABAergic circuits that modulate the dynamics of excitation-inhibition and disinhibition in the main output area of the hippocampus CA1, which is crucial for episodic memory. Specifically, we link recent findings pertaining to GABAergic neuron molecular markers, electrophysiological properties, and synaptic wiring with their function at the circuit level. Lastly, given that area CA1 is particularly impaired during early stages of Alzheimer's disease, we emphasize how these GABAergic circuits may contribute to and be involved in the pathophysiology.
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Affiliation(s)
- Melissa Hernández-Frausto
- Neuroscience Institute, New York University Langone Health, New York, NY, United States
- Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, NY, United States
| | - Olesia M. Bilash
- Neuroscience Institute, New York University Langone Health, New York, NY, United States
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Arjun V. Masurkar
- Neuroscience Institute, New York University Langone Health, New York, NY, United States
- Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, NY, United States
- Center for Cognitive Neurology, Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
| | - Jayeeta Basu
- Neuroscience Institute, New York University Langone Health, New York, NY, United States
- Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, NY, United States
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY, United States
- Center for Neural Science, New York University, New York, NY, United States
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5
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Zhang NK, Zhang SK, Zhang LI, Tao HW, Zhang GW. Sensory processing deficits and related cortical pathological changes in Alzheimer's disease. Front Aging Neurosci 2023; 15:1213379. [PMID: 37649717 PMCID: PMC10464619 DOI: 10.3389/fnagi.2023.1213379] [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: 04/27/2023] [Accepted: 07/24/2023] [Indexed: 09/01/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder primarily affecting cognitive functions. However, sensory deficits in AD start to draw attention due to their high prevalence and early onsets which suggest that they could potentially serve as diagnostic biomarkers and even contribute to the disease progression. This literature review examines the sensory deficits and cortical pathological changes observed in visual, auditory, olfactory, and somatosensory systems in AD patients, as well as in various AD animal models. Sensory deficits may emerge at the early stages of AD, or even precede the cognitive decline, which is accompanied by cortical pathological changes including amyloid-beta deposition, tauopathy, gliosis, and alterations in neuronal excitability, synaptic inputs, and functional plasticity. Notably, these changes are more pronounced in sensory association areas and superficial cortical layers, which may explain the relative preservation of basic sensory functions but early display of deficits of higher sensory functions. We propose that sensory impairment and the progression of AD may establish a cyclical relationship that mutually perpetuates each condition. This review highlights the significance of sensory deficits with or without cortical pathological changes in AD and emphasizes the need for further research to develop reliable early detection and intervention through sensory systems.
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Affiliation(s)
- Nicole K. Zhang
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Selena K. Zhang
- Biomedical Engineering Program, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, United States
| | - Li I. Zhang
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
- Department of Physiology & Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Huizhong W. Tao
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
- Department of Physiology & Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Guang-Wei Zhang
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
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6
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Green GS, Fujita M, Yang HS, Taga M, McCabe C, Cain A, White CC, Schmidtner AK, Zeng L, Wang Y, Regev A, Menon V, Bennett DA, Habib N, De Jager PL. Cellular dynamics across aged human brains uncover a multicellular cascade leading to Alzheimer's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.07.531493. [PMID: 36945609 PMCID: PMC10028913 DOI: 10.1101/2023.03.07.531493] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Alzheimer's Disease (AD) is a progressive neurodegenerative disease seen with advancing age. Recent studies have revealed diverse AD-associated cell states, yet when and how they impact the causal chain leading to AD remains unknown. To reconstruct the dynamics of the brain's cellular environment along the disease cascade and to distinguish between AD and aging effects, we built a comprehensive cell atlas of the aged prefrontal cortex from 1.64 million single-nucleus RNA-seq profiles. We associated glial, vascular and neuronal subpopulations with AD-related traits for 424 aging individuals, and aligned them along the disease cascade using causal modeling. We identified two distinct lipid-associated microglial subpopulations, one contributed to amyloid-β proteinopathy while the other mediated the effect of amyloid-β in accelerating tau proteinopathy, as well as an astrocyte subpopulation that mediated the effect of tau on cognitive decline. To model the coordinated dynamics of the entire cellular environment we devised the BEYOND methodology which uncovered two distinct trajectories of brain aging that are defined by distinct sequences of changes in cellular communities. Older individuals are engaged in one of two possible trajectories, each associated with progressive changes in specific cellular communities that end with: (1) AD dementia or (2) alternative brain aging. Thus, we provide a cellular foundation for a new perspective of AD pathophysiology that could inform the development of new therapeutic interventions targeting cellular communities, while designing a different clinical management for those individuals on the path to AD or to alternative brain aging.
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7
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Somatostatin slows Aβ plaque deposition in aged APP NL-F/NL-F mice by blocking Aβ aggregation. Sci Rep 2023; 13:2337. [PMID: 36759538 PMCID: PMC9911728 DOI: 10.1038/s41598-023-29559-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
The neuroendocrine peptide somatostatin (SST) has long been thought of as influencing the deposition of the amyloid β peptide (Aβ) in Alzheimer's disease (AD). Missing have been in vivo data in a relevant Aβ amyloidosis model. Here we crossed AppNL-F/NL-F mice with Sst-deficient mice to assess if and how the presence of Sst influences pathological hallmarks of Aβ amyloidosis. We found that Sst had no influence on whole brain neprilysin transcript, protein or activity levels, an observation that cannot be accounted for by a compensatory upregulation of the Sst paralog, cortistatin (Cort), that we observed in 15-month-old Sst-deficient mice. Sst-deficiency led to a subtle but significant increase in the density of cortical Aβ amyloid plaques. Follow-on western blot analyses of whole brain extracts indicated that Sst interferes with early steps of Aβ assembly that manifest in the appearance of SDS-stable smears of 55-150 kDa in Sst null brain samples. As expected, no effect of Sst on tau steady-state levels or its phosphorylation were observed. Results from this study are easier reconciled with an emerging body of data that point toward Sst affecting Aβ amyloid plaque formation through direct interference with Aβ aggregation rather than through its effects on neprilysin expression.
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8
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Almeida VN, Radanovic M. Semantic processing and neurobiology in Alzheimer's disease and Mild Cognitive Impairment. Neuropsychologia 2022; 174:108337. [DOI: 10.1016/j.neuropsychologia.2022.108337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/17/2022] [Accepted: 07/17/2022] [Indexed: 11/28/2022]
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9
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Li H, Zhao J, Lai L, Xia Y, Wan C, Wei S, Liang J, Chen Y, Xu N. Loss of SST and PV Positive Interneurons in the Ventral Hippocampus Results in Anxiety-like Behavior in 5xFAD Mice. Neurobiol Aging 2022; 117:165-178. [DOI: 10.1016/j.neurobiolaging.2022.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 05/13/2022] [Accepted: 05/28/2022] [Indexed: 10/18/2022]
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Somatostatin and Somatostatin-Containing Interneurons—From Plasticity to Pathology. Biomolecules 2022; 12:biom12020312. [PMID: 35204812 PMCID: PMC8869243 DOI: 10.3390/biom12020312] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/27/2022] [Accepted: 02/11/2022] [Indexed: 01/27/2023] Open
Abstract
Despite the obvious differences in the pathophysiology of distinct neuropsychiatric diseases or neurodegenerative disorders, some of them share some general but pivotal mechanisms, one of which is the disruption of excitation/inhibition balance. Such an imbalance can be generated by changes in the inhibitory system, very often mediated by somatostatin-containing interneurons (SOM-INs). In physiology, this group of inhibitory interneurons, as well as somatostatin itself, profoundly shapes the brain activity, thus influencing the behavior and plasticity; however, the changes in the number, density and activity of SOM-INs or levels of somatostatin are found throughout many neuropsychiatric and neurological conditions, both in patients and animal models. Here, we (1) briefly describe the brain somatostatinergic system, characterizing the neuropeptide somatostatin itself, its receptors and functions, as well the physiology and circuitry of SOM-INs; and (2) summarize the effects of the activity of somatostatin and SOM-INs in both physiological brain processes and pathological brain conditions, focusing primarily on learning-induced plasticity and encompassing selected neuropsychological and neurodegenerative disorders, respectively. The presented data indicate the somatostatinergic-system-mediated inhibition as a substantial factor in the mechanisms of neuroplasticity, often disrupted in a plethora of brain pathologies.
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11
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Neurophysiological basis of the N400 deflection, from Mismatch Negativity to Semantic Prediction Potentials and late positive components. Int J Psychophysiol 2021; 166:134-150. [PMID: 34097935 DOI: 10.1016/j.ijpsycho.2021.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/20/2021] [Accepted: 06/02/2021] [Indexed: 11/21/2022]
Abstract
The first theoretical model on the neurophysiological basis of the N400: the deflection reflects layer I dendritic plateaus on a preparatory state of synaptic integration that precedes layer V somatic burst firing for conscious identification of the higher-order features of the stimulus (a late positive shift). Plateaus ensue from apical disinhibition by vasoactive intestinal polypeptide-positive interneurons (VIPs) through suppression of Martinotti cells, opening the gates for glutamatergic feedback to trigger dendritic regenerative potentials. Cholinergic transients contribute to these dynamics directly, holding a central role in the N400 deflection. The stereotypical timing of the (frontal) glutamatergic feedback and the accompanying cholinergic transients account for the enigmatic "invariability" of the peak latency in the face of a gamut of different stimuli and paradigms. The theoretical postulations presented here may bring about unprecedented level of detail for the N400 deflection to be used in the study of schizophrenia, Alzheimer's disease and other higher-order pathologies. The substrates of a late positive component, the Mismatch Negativity and the Semantic Prediction Potentials are also surveyed.
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12
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Reid HMO, Chen-Mack N, Snowden T, Christie BR. Understanding Changes in Hippocampal Interneurons Subtypes in the Pathogenesis of Alzheimer's Disease: A Systematic Review. Brain Connect 2021; 11:159-179. [PMID: 33559520 DOI: 10.1089/brain.2020.0879] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Background: It is becoming increasingly recognized that there is significant interneuron degeneration in Alzheimer's disease. As the hippocampus is integral for learning and memory, we performed a systematic review of primary literature focused on the relationship between Alzheimer's and hippocampal interneurons. In this study, we summarize the experimental work performed to date and identify opportunities for future experiments. Objectives: This PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses)-style systematic review seeks to summarize the findings of all accessible research focused on cholecystokinin (CCK), neuropeptide Y (NPY), parvalbumin (PV), and somatostatin (SOM) interneurons in the hippocampal formation. Results: One thousand five hundred ninety-three articles were pulled from PubMed, PsycInfo, and Web of Science, based on three blocks of search terms. There were 45 articles that met all the predetermined inclusion/exclusion criteria. There is strong evidence that PV interneurons are affected early in the disease by toxic amyloid beta (Aβ) fragments; SOM interneurons are affected indirectly while the SOM neuropeptide may act to slowly worsen toxic Aβ fragment accumulation, whereas NPY- and CCK-positive interneurons are affected later in the progression of the disease. Conclusions: Fewer studies have been performed on NPY and CCK interneurons, and there is room for further investigations regarding the role of PV interneurons in Alzheimer's to help resolve contradictory findings. This review found that PV interneurons are affected early in the disease, but only in Alzheimer's precursor protein but not tau models. NPY and CCK interneurons were found to be affected later in the disease, and SOM interneurons vary greatly. Future studies may consider reporting immunohistochemical studies inclusive of either cell location or morphology-as well as marker to give a more robust picture of the disease.
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Affiliation(s)
- Hannah M O Reid
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - Nathan Chen-Mack
- Island Medical Program and Department of Cellular and Physiological Sciences, University of British Columbia, Victoria, British Columbia, Canada
| | - Taylor Snowden
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - Brian R Christie
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada
- Island Medical Program and Department of Cellular and Physiological Sciences, University of British Columbia, Victoria, British Columbia, Canada
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13
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Preoperative Chronic and Acute Pain Affects Postoperative Cognitive Function Mediated by Neurotransmitters. J Mol Neurosci 2020; 71:515-526. [PMID: 32901371 DOI: 10.1007/s12031-020-01673-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 07/20/2020] [Indexed: 02/08/2023]
Abstract
The effective prevention of postoperative cognitive dysfunction (POCD) needs to be explored, and the effect of preoperative pain on POCD remains unclear. We established a chronic pain model induced by chronic constriction injury (CCI) and models of acute pain and anxiety without pain in mice that were subsequently subjected to partial hepatectomy surgery. Morris water maze (MWM) tests were performed to evaluate the learning and memory abilities of the mice. ELISA was used to measure IL-1β, IL-6, and TNF-α in serum, and HPLC-MS was used to detect neurotransmitters in the prefrontal cortices and hippocampi of the mice. The results indicated that chronic pain induced by CCI might have significantly impaired the learning and memory abilities of mice, while acute pain and anxiety without pain only affected the memory abilities of mice. Perioperative acute pain increased the level of IL-1β in serum, and CCI might have increased the level of IL-6. CCI and acute pain increased dopamine (DA) levels in the cortex, similar to anxiety. Like anxiety, CCI increased 5-hydroxytryptamine (5-HT) levels in the prefrontal cortex and hippocampus. Acute pain led to a decrease in the acetylcholine (ACH) level in the hippocampus. Our results suggest that acute pain and CCI-induced chronic pain might aggravate postoperative cognitive dysfunction via neurotransmitters and by changing the levels of inflammatory factors such as IL-1β and IL-6.
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