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Chen Z, Wang S, Meng Z, Ye Y, Shan G, Wang X, Zhao X, Jin Y. Tau protein plays a role in the mechanism of cognitive disorders induced by anesthetic drugs. Front Neurosci 2023; 17:1145318. [PMID: 36937655 PMCID: PMC10015606 DOI: 10.3389/fnins.2023.1145318] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 02/13/2023] [Indexed: 03/08/2023] Open
Abstract
Cognitive disorders are mental health disorders that can affect cognitive ability. Surgery and anesthesia have been proposed to increase the incidence of cognitive dysfunction, including declines in memory, learning, attention and executive function. Tau protein is a microtubule-associated protein located in the axons of neurons and is important for microtubule assembly and stability; its biological function is mainly regulated by phosphorylation. Phosphorylated tau protein has been associated with cognitive dysfunction mediated by disrupting the stability of the microtubule structure. There is an increasing consensus that anesthetic drugs can cause cognitive impairment. Herein, we reviewed the latest literature and compared the relationship between tau protein and cognitive impairment caused by different anesthetics. Our results substantiated that tau protein phosphorylation is essential in cognitive dysfunction caused by anesthetic drugs, and the possible mechanism can be summarized as "anesthetic drugs-kinase/phosphatase-p-Tau-cognitive impairment".
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Ali AB, Islam A, Constanti A. The fate of interneurons, GABA A receptor sub-types and perineuronal nets in Alzheimer's disease. Brain Pathol 2022; 33:e13129. [PMID: 36409151 PMCID: PMC9836378 DOI: 10.1111/bpa.13129] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 10/12/2022] [Indexed: 11/23/2022] Open
Abstract
Alzheimer's disease (AD) is the most common neurological disease, which is associated with gradual memory loss and correlated with synaptic hyperactivity and abnormal oscillatory rhythmic brain activity that precedes phenotypic alterations and is partly responsible for the spread of the disease pathology. Synaptic hyperactivity is thought to be because of alteration in the homeostasis of phasic and tonic synaptic inhibition, which is orchestrated by the GABAA inhibitory system, encompassing subclasses of interneurons and GABAA receptors, which play a vital role in cognitive functions, including learning and memory. Furthermore, the extracellular matrix, the perineuronal nets (PNNs) which often go unnoticed in considerations of AD pathology, encapsulate the inhibitory cells and neurites in critical brain regions and have recently come under the light for their crucial role in synaptic stabilisation and excitatory-inhibitory balance and when disrupted, serve as a potential trigger for AD-associated synaptic imbalance. Therefore, in this review, we summarise the current understanding of the selective vulnerability of distinct interneuron subtypes, their synaptic and extrasynaptic GABAA R subtypes as well as the changes in PNNs in AD, detailing their contribution to the mechanisms of disease development. We aim to highlight how seemingly unique malfunction in each component of the interneuronal GABA inhibitory system can be tied together to result in critical circuit dysfunction, leading to the irreversible symptomatic damage observed in AD.
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Oh SJ, Lee N, Nam KR, Kang KJ, Han SJ, Lee KC, Lee YJ, Choi JY. Amyloid pathology induces dysfunction of systemic neurotransmission in aged APPswe/PS2 mice. Front Neurosci 2022; 16:930613. [PMID: 35992913 PMCID: PMC9389227 DOI: 10.3389/fnins.2022.930613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 07/15/2022] [Indexed: 11/21/2022] Open
Abstract
This study aimed to investigate how amyloid pathology affects the functional aspects of neurotransmitter systems in Alzheimer’s disease. APPswe/PS2 mice (21 months of age) and wild-type (WT) mice underwent positron emission tomography (PET) and magnetic resonance spectroscopy (MRS). First, we obtained 18F-FDG and 18F-florbetaben PET scans to evaluate neuronal integrity and amyloid pathology. Second, 18F-FPEB and 18F-FMZ PET data were acquired to assess the excitatory-inhibitory neurotransmission. Third, to monitor the dopamine system, 18F-fallypride PET was performed. Amyloid PET imaging revealed that radioactivity was higher in the AD group than that in the WT group, which was validated by immunohistochemistry. In the cortical and limbic areas, the AD group showed a 25–27% decrease and 14–35% increase in the glutamatergic and GABAergic systems, respectively. The dopaminergic system in the AD group exhibited a 29% decrease in brain uptake compared with that in the WT group. A reduction in glutamate, N-acetylaspartate, and taurine levels was observed in the AD group using MRS. Our results suggest that dysfunction of the neurotransmitter system is associated with AD pathology. Among the systems, the GABAergic system was prominent, implying that the inhibitory neurotransmission system may be the most vulnerable to AD pathology.
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Affiliation(s)
- Se Jong Oh
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Namhun Lee
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Kyung Rok Nam
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Kyung Jun Kang
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Sang Jin Han
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Kyo Chul Lee
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Yong Jin Lee
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Jae Yong Choi
- Division of Applied RI, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
- Radiological and Medico-Oncological Sciences, University of Science and Technology (UST), Seoul, South Korea
- *Correspondence: Jae Yong Choi,
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Kang Y, Jamison K, Jaywant A, Dams-O’Connor K, Kim N, Karakatsanis NA, Butler T, Schiff ND, Kuceyeski A, Shah SA. Longitudinal alterations in gamma-aminobutyric acid (GABAA) receptor availability over ∼ 1 year following traumatic brain injury. Brain Commun 2022; 4:fcac159. [PMID: 35794871 PMCID: PMC9253887 DOI: 10.1093/braincomms/fcac159] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 03/24/2022] [Accepted: 06/14/2022] [Indexed: 11/25/2022] Open
Abstract
Longitudinal alterations of gamma-aminobutyric acid (GABAA) receptor availability following traumatic brain injury have remained uncharacterized and may reflect changes in neuronal structure and function linked to cognitive recovery. We measured GABAA receptor availability using the tracer [11C]flumazenil in nine adults with traumatic brain injury (3–6 months after injury, subacute scan) and in 20 non-brain-injured individuals. A subset of subjects with traumatic brain injury (n = 7) were scanned at a second chronic time-point, 7–13 months after their first scan; controls (n = 9) were scanned for a second time, 5–11 months after the first scan. After accounting for atrophy in subjects with traumatic brain injury, we find broad decreases in GABAA receptor availability predominantly within the frontal lobes, striatum, and posterior-medial thalami; focal reductions were most pronounced in the right insula and anterior cingulate cortex (p < 0.05). Greater relative increase, compared to controls, in global GABAA receptor availability appeared between subacute and chronic scans. At chronic scan (>1 year post-injury), we find increased pallidal receptor availability compared to controls. Conversely, receptor availability remained depressed across the frontal cortices. Longitudinal improvement in executive attention correlated with increases in receptor availability across bilateral fronto-parietal cortical regions and the anterior-lateral aspects of the thalami. The specific observations of persistent bi-frontal lobe reductions and bilateral pallidal elevation are consistent with the anterior forebrain mesocircuit hypothesis for recovery of consciousness following a wide range of brain injuries; our results provide novel correlative data in support of specific cellular mechanisms underlying persistent cognitive deficits. Collectively, these measurements support the use of [11C]flumazenil to track recovery of large-scale network function following brain injuries and measure response to therapeutics.
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Affiliation(s)
- Y Kang
- Department of Mathematics, Howard University , Washington, DC 20059 , USA
| | - K Jamison
- Department of Radiology, Weill Cornell Medicine , 407 E. 61 St., Rm 208, New York, NY 10065 , USA
| | - A Jaywant
- Department of Rehabilitation Medicine, Weill Cornell Medicine , New York, NY 10065 , USA
- Department of Psychiatry, Weill Cornell Medicine , New York, NY 10065 , USA
| | - K Dams-O’Connor
- Department of Rehabilitation and Human Performance, Icahn School of Medicine at Mount Sinai , New York, NY 10029 , USA
- Department of Neurology, Icahn School of Medicine at Mount Sinai , New York, NY 10029 , USA
| | - N Kim
- Department of Radiology, Weill Cornell Medicine , 407 E. 61 St., Rm 208, New York, NY 10065 , USA
| | - N A Karakatsanis
- Department of Radiology, Weill Cornell Medicine , 407 E. 61 St., Rm 208, New York, NY 10065 , USA
| | - T Butler
- Department of Radiology, Weill Cornell Medicine , 407 E. 61 St., Rm 208, New York, NY 10065 , USA
| | - N D Schiff
- Department of BMRI & Neurology, Weill Cornell Medicine , New York, NY 10065 , USA
| | - A Kuceyeski
- Department of Radiology, Weill Cornell Medicine , 407 E. 61 St., Rm 208, New York, NY 10065 , USA
| | - S A Shah
- Department of Radiology, Weill Cornell Medicine , 407 E. 61 St., Rm 208, New York, NY 10065 , USA
- Department of BMRI & Neurology, Weill Cornell Medicine , New York, NY 10065 , USA
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Capsoni S, Arisi I, Malerba F, D’Onofrio M, Cattaneo A, Cherubini E. Targeting the Cation-Chloride Co-Transporter NKCC1 to Re-Establish GABAergic Inhibition and an Appropriate Excitatory/Inhibitory Balance in Selective Neuronal Circuits: A Novel Approach for the Treatment of Alzheimer's Disease. Brain Sci 2022; 12:brainsci12060783. [PMID: 35741668 PMCID: PMC9221351 DOI: 10.3390/brainsci12060783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 01/27/2023] Open
Abstract
GABA, the main inhibitory neurotransmitter in the adult brain, depolarizes and excites immature neurons because of an initially higher intracellular chloride concentration [Cl-]i due to the delayed expression of the chloride exporter KCC2 at birth. Depolarization-induced calcium rise via NMDA receptors and voltage-dependent calcium channels is instrumental in shaping neuronal circuits and in controlling the excitatory (E)/inhibitory (I) balance in selective brain areas. An E/I imbalance accounts for cognitive impairment observed in several neuropsychiatric disorders. The aim of this review is to summarize recent data on the mechanisms by which alterations of GABAergic signaling alter the E/I balance in cortical and hippocampal neurons in Alzheimer's disease (AD) and the role of cation-chloride co-transporters in this process. In particular, we discuss the NGF and AD relationship and how mice engineered to express recombinant neutralizing anti-NGF antibodies (AD11 mice), which develop a neurodegenerative pathology reminiscent of that observed in AD patients, exhibit a depolarizing action of GABA due to KCC2 impairment. Treating AD and other forms of dementia with bumetanide, a selective KCC2 antagonist, contributes to re-establishing a proper E/I balance in selective brain areas, leading to amelioration of AD symptoms and the slowing down of disease progression.
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Affiliation(s)
- Simona Capsoni
- Bio@SNS Laboratory of Biology, Scuola Normale Superiore, 56126 Pisa, Italy;
- Section of Physiology, Department of Neuroscience and Rehabilitation, University of Ferrara, 44121 Ferrara, Italy
| | - Ivan Arisi
- Fondazione European Brain Research Institute (EBRI) Rita Levi-Montalcini, 00161 Rome, Italy; (I.A.); (F.M.); (M.D.)
| | - Francesca Malerba
- Fondazione European Brain Research Institute (EBRI) Rita Levi-Montalcini, 00161 Rome, Italy; (I.A.); (F.M.); (M.D.)
| | - Mara D’Onofrio
- Fondazione European Brain Research Institute (EBRI) Rita Levi-Montalcini, 00161 Rome, Italy; (I.A.); (F.M.); (M.D.)
| | - Antonino Cattaneo
- Bio@SNS Laboratory of Biology, Scuola Normale Superiore, 56126 Pisa, Italy;
- Fondazione European Brain Research Institute (EBRI) Rita Levi-Montalcini, 00161 Rome, Italy; (I.A.); (F.M.); (M.D.)
- Correspondence: (A.C.); (E.C.); Tel.: +39-050-509320 (A.C.); +39-06-49255255 (E.C.)
| | - Enrico Cherubini
- Fondazione European Brain Research Institute (EBRI) Rita Levi-Montalcini, 00161 Rome, Italy; (I.A.); (F.M.); (M.D.)
- Correspondence: (A.C.); (E.C.); Tel.: +39-050-509320 (A.C.); +39-06-49255255 (E.C.)
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Prominent gamma band activity during visual motion perception in early-stage Alzheimer’s disease. PLoS One 2022; 17:e0266693. [PMID: 35436287 PMCID: PMC9015152 DOI: 10.1371/journal.pone.0266693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 03/24/2022] [Indexed: 11/19/2022] Open
Abstract
Introduction Alzheimer’s disease (AD) affects multiple neural pathways and regions, resulting in various visual impairments such as motion perception. Generally, gamma-band activities during visual motion perception have been thought to reflect ongoing cognitive processes. Nevertheless, few studies have specifically examined induced gamma band activity during visual motion perception in AD patients. Therefore, after performing magnetoencephalography (MEG) recording during apparent motion (AM) stimulation for the left hemi-visual field in patients diagnosed as having AD in the early stage, we compared the results with findings of cognitive performance. Methods Seventeen AD patients in the early stage and 17 controls matched for age, sex, and educational attainment participated in this study. For each participant, memory performance was assessed with the Mini-Mental State Examination (MMSE) and the Wechsler Memory Scale-Revised (WMS-R). For MEG analysis, we examined power changes induced in a higher frequency range (20–100 Hz) after AM stimuli. Results The power of induced gamma band activities was significantly higher in AD patients. The power of induced gamma band activities was associated with higher performance on both MMSE and WMS-R tests for attention and concentration in AD patients. Conclusions Given that neuronal dysfunction in AD is associated with excitotoxic neurodegeneration, and given that subsequent development of compensatory inhibitory mechanisms also contributes to pathology in AD patients, elevated gamma band oscillations might reflect an imbalance of inhibitory and excitatory activity in AD patients. Moreover, positive correlation between induced gamma activity and cognitive performance might signify a compensating mechanism of inhibitory neurons which preserve the pyramidal neuron from excitotoxicity in a posterior association area.
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Key Genes and Biochemical Networks in Various Brain Regions Affected in Alzheimer's Disease. Cells 2022; 11:cells11060987. [PMID: 35326437 PMCID: PMC8946735 DOI: 10.3390/cells11060987] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/02/2022] [Accepted: 03/10/2022] [Indexed: 12/27/2022] Open
Abstract
Alzheimer’s disease (AD) is one of the most complicated progressive neurodegenerative brain disorders, affecting millions of people around the world. Ageing remains one of the strongest risk factors associated with the disease and the increasing trend of the ageing population globally has significantly increased the pressure on healthcare systems worldwide. The pathogenesis of AD is being extensively investigated, yet several unknown key components remain. Therefore, we aimed to extract new knowledge from existing data. Ten gene expression datasets from different brain regions including the hippocampus, cerebellum, entorhinal, frontal and temporal cortices of 820 AD cases and 626 healthy controls were analyzed using the robust rank aggregation (RRA) method. Our results returned 1713 robust differentially expressed genes (DEGs) between five brain regions of AD cases and healthy controls. Subsequent analysis revealed pathways that were altered in each brain region, of which the GABAergic synapse pathway and the retrograde endocannabinoid signaling pathway were shared between all AD affected brain regions except the cerebellum, which is relatively less sensitive to the effects of AD. Furthermore, we obtained common robust DEGs between these two pathways and predicted three miRNAs as potential candidates targeting these genes; hsa-mir-17-5p, hsa-mir-106a-5p and hsa-mir-373-3p. Three transcription factors (TFs) were also identified as the potential upstream regulators of the robust DEGs; ELK-1, GATA1 and GATA2. Our results provide the foundation for further research investigating the role of these pathways in AD pathogenesis, and potential application of these miRNAs and TFs as therapeutic and diagnostic targets.
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Ethiraj J, Palpagama TH, Turner C, van der Werf B, Waldvogel HJ, Faull RLM, Kwakowsky A. The effect of age and sex on the expression of GABA signaling components in the human hippocampus and entorhinal cortex. Sci Rep 2021; 11:21470. [PMID: 34728681 PMCID: PMC8563768 DOI: 10.1038/s41598-021-00792-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 10/14/2021] [Indexed: 12/02/2022] Open
Abstract
Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the nervous system. The GABA signaling system in the brain is comprised of GABA synthesizing enzymes, transporters, GABAA and GABAB receptors (GABAAR and GABABR). Alterations in the expression of these signaling components have been observed in several brain regions throughout aging and between sexes in various animal models. The hippocampus is the memory centre of the brain and is impaired in several age-related disorders. It is composed of two main regions: the Cornu Ammonis (CA1-4) and the Dentate Gyrus (DG), which are interconnected with the Entorhinal Cortex (ECx). The age- and sex-specific changes of GABA signaling components in these regions of the human brain have not been examined. This study is the first to determine the effect of age and sex on the expression of GABA signaling components-GABAAR α1,2,3,5, β1-3, γ2, GABABR R1 and R2 subunits and the GABA synthesizing enzymes GAD 65/67-in the ECx, and the CA1 and DG regions of the human hippocampus using Western blotting. No significant differences were found in GABAAR α1,2,3,5, β1-3, γ2, GABABR R1 and R2 subunit and GAD65/76 expression levels in the ECx, CA1 and DG regions between the younger and older age groups for both sexes. However, we observed a significant negative correlation between age and GABAAR α1subunit level in the CA1 region for females; significant negative correlation between age and GABAAR β1, β3 and γ2 subunit expression in the DG region for males. In females a significant positive correlation was found between age and GABAAR γ2 subunit expression in the ECx and GABABR R2 subunit expression in the CA1 region. The results indicate that age and sex do not affect the expression of GAD 65/67. In conclusion, our results show age- and sex-related GABAA/BR subunit alterations in the ECx and hippocampus that might significantly influence GABAergic neurotransmission and underlie disease susceptibility and progression.
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Affiliation(s)
- Jayarjun Ethiraj
- grid.9654.e0000 0004 0372 3343Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Thulani Hansika Palpagama
- grid.9654.e0000 0004 0372 3343Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Clinton Turner
- grid.9654.e0000 0004 0372 3343Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, School of Medical Sciences, University of Auckland, Auckland, New Zealand ,grid.414055.10000 0000 9027 2851Department of Anatomical Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand
| | - Bert van der Werf
- grid.9654.e0000 0004 0372 3343Department of Epidemiology and Biostatistics, Faculty of Medical and Health Sciences, School of Population Health, University of Auckland, Auckland, New Zealand
| | - Henry John Waldvogel
- grid.9654.e0000 0004 0372 3343Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Richard Lewis Maxwell Faull
- grid.9654.e0000 0004 0372 3343Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Andrea Kwakowsky
- grid.9654.e0000 0004 0372 3343Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, School of Medical Sciences, University of Auckland, Auckland, New Zealand
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Hammoud H, Netsyk O, Tafreshiha AS, Korol SV, Jin Z, Li J, Birnir B. Insulin differentially modulates GABA signalling in hippocampal neurons and, in an age-dependent manner, normalizes GABA-activated currents in the tg-APPSwe mouse model of Alzheimer's disease. Acta Physiol (Oxf) 2021; 232:e13623. [PMID: 33559388 DOI: 10.1111/apha.13623] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/29/2021] [Accepted: 02/03/2021] [Indexed: 02/06/2023]
Abstract
AIM We examined if tonic γ-aminobutyric acid (GABA)-activated currents in primary hippocampal neurons were modulated by insulin in wild-type and tg-APPSwe mice, an Alzheimer's disease (AD) model. METHODS GABA-activated currents were recorded in dentate gyrus (DG) granule cells and CA3 pyramidal neurons in hippocampal brain slices, from 8 to 10 weeks old (young) wild-type mice and in dorsal DG granule cells in adult, 5-6 and 10-12 (aged) months old wild-type and tg-APPSwe mice, in the absence or presence of insulin, by whole-cell patch-clamp electrophysiology. RESULTS In young mice, insulin (1 nmol/L) enhanced the total spontaneous inhibitory postsynaptic current (sIPSCT ) density in both dorsal and ventral DG granule cells. The extrasynaptic current density was only increased by insulin in dorsal CA3 pyramidal neurons. In absence of action potentials, insulin enhanced DG granule cells and dorsal CA3 pyramidal neurons miniature IPSC (mIPSC) frequency, consistent with insulin regulation of presynaptic GABA release. sIPSCT densities in DG granule cells were similar in wild-type and tg-APPSwe mice at 5-6 months but significantly decreased in aged tg-APPSwe mice where insulin normalized currents to wild-type levels. The extrasynaptic current density was increased in tg-APPSwe mice relative to wild-type littermates but, only in aged tg-APPSwe mice did insulin decrease and normalize the current. CONCLUSION Insulin effects on GABA signalling in hippocampal neurons are selective while multifaceted and context-based. Not only is the response to insulin related to cell-type, hippocampal axis-location, age of animals and disease but also to the subtype of neuronal inhibition involved, synaptic or extrasynaptic GABAA receptors-activated currents.
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Affiliation(s)
- Hayma Hammoud
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
| | - Olga Netsyk
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
| | | | - Sergiy V. Korol
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
| | - Zhe Jin
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
| | - Jin‐Ping Li
- Department of Medical Biochemistry and Microbiology Uppsala University Uppsala Sweden
| | - Bryndis Birnir
- Department of Medical Cell Biology Uppsala University Uppsala Sweden
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Richardson K, Wharton SB, Grossi CM, Matthews FE, Fox C, Maidment I, Loke YK, Steel N, Arthur A, Myint PK, Boustani M, Campbell N, Robinson L, Brayne C, Savva GM. Neuropathological Correlates of Cumulative Benzodiazepine and Anticholinergic Drug Use. J Alzheimers Dis 2021; 74:999-1009. [PMID: 32116256 DOI: 10.3233/jad-191199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Benzodiazepines and anticholinergic drugs have been implicated in causing cognitive decline and potentially increasing dementia risk. However, evidence for an association with neuropathology is limited. OBJECTIVE To estimate the correlation between neuropathology at death and prior use of benzodiazepines and anticholinergic drugs. METHODS We categorized 298 brain donors from the population-based Medical Research Council Cognitive Function and Ageing Study, according to their history of benzodiazepine (including Z-drugs) or anticholinergic medication (drugs scoring 3 on the Anticholinergic Cognitive Burden scale) use. We used logistic regression to compare dichotomized neuropathological features for those with and without history of benzodiazepine and anticholinergic drug use before dementia, adjusted for confounders. RESULTS Forty-nine (16%) and 51 (17%) participants reported benzodiazepine and anticholinergic drug use. Alzheimer's disease neuropathologic change was similar whether or not exposed to either drug, for example 46% and 57% had intermediate/high levels among those with and without anticholinergic drug use. Although not significant after multiple testing adjustments, we estimated an odds ratio (OR) of 0.40 (95% confidence interval [95% CI] 0.18-0.87) for anticholinergic use and cortical atrophy. For benzodiazepine use, we estimated ORs of 4.63 (1.11-19.24) and 3.30 (1.02-10.68) for neuronal loss in the nucleus basalis and substantial nigra. There was evidence of neuronal loss in the nucleus basalis with anticholinergic drug use, but the association reduced when adjusted for confounders. CONCLUSIONS We found no evidence that benzodiazepine or anticholinergic drug use is associated with typical pathological features of Alzheimer's disease; however, we cannot rule out effects owing to small numbers.
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Affiliation(s)
| | - Stephen B Wharton
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Carlota M Grossi
- School of Health Sciences, University of East Anglia, Norwich, UK
| | - Fiona E Matthews
- Institute of Health and Society/Institute for Ageing, Newcastle University, Newcastle, UK
| | - Chris Fox
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - Ian Maidment
- School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Yoon K Loke
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - Nicholas Steel
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - Antony Arthur
- School of Health Sciences, University of East Anglia, Norwich, UK
| | - Phyo Kyaw Myint
- Institute of Applied Health Sciences, University of Aberdeen, Aberdeen, UK
| | - Malaz Boustani
- School of Medicine, Indiana University, Indianapolis, IN, USA
| | - Noll Campbell
- Department of Pharmacy Practice, Purdue University, West Lafayette, IN, USA
| | - Louise Robinson
- Institute of Health and Society/Institute for Ageing, Newcastle University, Newcastle, UK
| | - Carol Brayne
- Cambridge Institute of Public Health, University of Cambridge, Cambridge, UK
| | - George M Savva
- School of Health Sciences, University of East Anglia, Norwich, UK.,Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
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11
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Wu Z, Shou L, Wang J, Huang T, Xu X. The Methylation Pattern for Knee and Hip Osteoarthritis. Front Cell Dev Biol 2020; 8:602024. [PMID: 33240895 PMCID: PMC7677303 DOI: 10.3389/fcell.2020.602024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 10/22/2020] [Indexed: 01/08/2023] Open
Abstract
Osteoarthritis is one of the most prevalent chronic joint diseases for middle-aged and elderly people. But in recent years, the number of young people suffering from the disease increases quickly. It is known that osteoarthritis is a common degenerative disease caused by the combination and interaction of many factors such as natural and environmental factors. DNA methylations reflect the effects of environmental factors. Several researches on DNA methylation at specific genes in OA cartilage indicated the great potential roles of DNA methylation in OA. To systematically investigate the methylation pattern in knee and hip osteoarthritis, we analyzed the methylation profiles in cartilage of 16 OA hip samples, 19 control hip samples and 62 OA knee samples. 12 discriminative methylation sites were identified using advanced minimal Redundancy Maximal Relevance (mRMR) and Incremental Feature Selection (IFS) methods. The SVM classifier of these 12 methylation sites from genes like MEIS1, GABRG3, RXRA, and EN1, can perfectly classify the OA hip samples, control hip samples and OA knee samples evaluated with LOOCV (Leave-One Out-Cross Validation). These 12 methylation sites can not only serve as biomarker, but also provide underlying mechanism of OA.
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Affiliation(s)
- Zhen Wu
- Departmemt of Orthopaedics, Tongde Hospital of Zhejiang Province, Hangzhou, China
| | - Lu Shou
- Departmemt of Pneumology, Tongde Hospital of Zhejiang Province, Hangzhou, China
| | - Jian Wang
- Departmemt of Orthopaedics, Tongde Hospital of Zhejiang Province, Hangzhou, China
| | - Tao Huang
- Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Xinwei Xu
- Departmemt of Orthopaedics, Tongde Hospital of Zhejiang Province, Hangzhou, China
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12
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Impaired Expression of GABA Signaling Components in the Alzheimer's Disease Middle Temporal Gyrus. Int J Mol Sci 2020; 21:ijms21228704. [PMID: 33218044 PMCID: PMC7698927 DOI: 10.3390/ijms21228704] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/13/2020] [Accepted: 11/16/2020] [Indexed: 12/26/2022] Open
Abstract
γ-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter, playing a central role in the regulation of cortical excitability and the maintenance of the excitatory/inhibitory (E/I) balance. Several lines of evidence point to a remodeling of the cerebral GABAergic system in Alzheimer’s disease (AD), with past studies demonstrating alterations in GABA receptor and transporter expression, GABA synthesizing enzyme activity and focal GABA concentrations in post-mortem tissue. AD is a chronic neurodegenerative disorder with a poorly understood etiology and the temporal cortex is one of the earliest regions in the brain to be affected by AD neurodegeneration. Utilizing NanoString nCounter analysis, we demonstrate here the transcriptional downregulation of several GABA signaling components in the post-mortem human middle temporal gyrus (MTG) in AD, including the GABAA receptor α1, α2, α3, α5, β1, β2, β3, δ, γ2, γ3, and θ subunits and the GABAB receptor 2 (GABABR2) subunit. In addition to this, we note the transcriptional upregulation of the betaine-GABA transporter (BGT1) and GABA transporter 2 (GAT2), and the downregulation of the 67 kDa isoform of glutamate decarboxylase (GAD67), the primary GABA synthesizing enzyme. The functional consequences of these changes require further investigation, but such alterations may underlie disruptions to the E/I balance that are believed to contribute to cognitive decline in AD.
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13
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Vinnakota C, Govindpani K, Tate WP, Peppercorn K, Anekal PV, Waldvogel HJ, Faull RLM, Kwakowsky A. An 5 GABAA Receptor Inverse Agonist, 5IA, Attenuates Amyloid Beta-Induced Neuronal Death in Mouse Hippocampal Cultures. Int J Mol Sci 2020; 21:ijms21093284. [PMID: 32384683 PMCID: PMC7247548 DOI: 10.3390/ijms21093284] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 12/30/2022] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder for which no cognition-restoring therapies exist. Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the brain. Increasing evidence suggests a remodeling of the GABAergic system in AD, which might represent an important therapeutic target. An inverse agonist of α5 subunit-containing GABAA receptors (α5GABAARs), 3-(5-Methylisoxazol-3-yl)-6-[(1-methyl-1,2,3-triazol-4-yl)methyloxy]-1,2,4-triazolo[3–a]phthalazine (α5IA) has cognition-enhancing properties. This study aimed to characterize the effects of α5IA on amyloid beta (Aβ1–42)-induced molecular and cellular changes. Mouse primary hippocampal cultures were exposed to either Aβ1-42 alone, or α5IA alone, α5IA with Aβ1–42 or vehicle alone, and changes in cell viability and mRNA expression of several GABAergic signaling components were assessed. Treatment with 100 nM of α5IA reduced Aβ1–42-induced cell loss by 23.8% (p < 0.0001) after 6 h and by 17.3% after 5 days of treatment (p < 0.0001). Furthermore, we observed an Aβ1-42-induced increase in ambient GABA levels, as well as upregulated mRNA expression of the GABAAR α2,α5,β2/3 subunits and the GABABR R1 and R2 subunits. Such changes in GABARs expression could potentially disrupt inhibitory neurotransmission and normal network activity. Treatment with α5IA restored Aβ1-42-induced changes in the expression of α5GABAARs. In summary, this compound might hold neuroprotective potential and represent a new therapeutic avenue for AD.
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Affiliation(s)
- Chitra Vinnakota
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health, Sciences, University of Auckland, Auckland 1023, New Zealand; (C.V.); (K.G.); (H.J.W.); (R.L.M.F.)
| | - Karan Govindpani
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health, Sciences, University of Auckland, Auckland 1023, New Zealand; (C.V.); (K.G.); (H.J.W.); (R.L.M.F.)
| | - Warren Perry Tate
- Department of Biochemistry, University of Otago, Dunedin 9054, New Zealand; (W.P.T.); (K.P.)
| | - Katie Peppercorn
- Department of Biochemistry, University of Otago, Dunedin 9054, New Zealand; (W.P.T.); (K.P.)
| | - Praju Vikas Anekal
- Biomedical Imaging Research Unit, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1023, New Zealand;
| | - Henry John Waldvogel
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health, Sciences, University of Auckland, Auckland 1023, New Zealand; (C.V.); (K.G.); (H.J.W.); (R.L.M.F.)
| | - Richard Lewis Maxwell Faull
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health, Sciences, University of Auckland, Auckland 1023, New Zealand; (C.V.); (K.G.); (H.J.W.); (R.L.M.F.)
| | - Andrea Kwakowsky
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health, Sciences, University of Auckland, Auckland 1023, New Zealand; (C.V.); (K.G.); (H.J.W.); (R.L.M.F.)
- Correspondence: ; Tel.: +64-9923-9346
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14
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Kwakowsky A, Calvo-Flores Guzmán B, Pandya M, Turner C, Waldvogel HJ, Faull RL. GABA A receptor subunit expression changes in the human Alzheimer's disease hippocampus, subiculum, entorhinal cortex and superior temporal gyrus. J Neurochem 2019; 145:374-392. [PMID: 29485232 DOI: 10.1111/jnc.14325] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 01/17/2018] [Accepted: 02/12/2018] [Indexed: 12/14/2022]
Abstract
Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system. GABA type A receptors (GABAA Rs) are severely affected in Alzheimer's disease (AD). However, the distribution and subunit composition of GABAA Rs in the AD brain are not well understood. This is the first comprehensive study to show brain region- and cell layer-specific alterations in the expression of the GABAA R subunits α1-3, α5, β1-3 and γ2 in the human AD hippocampus, entorhinal cortex and superior temporal gyrus. In late-stage AD tissue samples using immunohistochemistry we found significant alteration of all investigated GABAA Rs subunits except for α3 and β1 that were well preserved. The most prominent changes include an increase in GABAA R α1 expression associated with AD in all layers of the CA3 region, in the stratum (str.) granulare and hilus of the dentate gyrus. We found a significant increase in GABAA R α2 expression in the str. oriens of the CA1-3, str. radiatum of the CA2,3 and decrease in the str. pyramidale of the CA1 region in AD cases. In AD there was a significant increase in GABAA R α5 subunit expression in str. pyramidale, str. oriens of the CA1 region and decrease in the superior temporal gyrus. We also found a significant decrease in the GABAA R β3 subunit immunoreactivity in the str. oriens of the CA2, str. granulare and str. moleculare of the dentate gyrus. In conclusion, these findings indicate that the expression of the GABAA R subunits shows brain region- and layer-specific alterations in AD, and these changes could significantly influence and alter GABAA R function in the disease. Cover Image for this issue: doi: 10.1111/jnc.14179.
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Affiliation(s)
- Andrea Kwakowsky
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Beatriz Calvo-Flores Guzmán
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Madhavi Pandya
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Clinton Turner
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.,Department of Anatomical Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand
| | - Henry J Waldvogel
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Richard L Faull
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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15
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Unsupervised excitation: GABAergic dysfunctions in Alzheimer’s disease. Brain Res 2019; 1707:216-226. [DOI: 10.1016/j.brainres.2018.11.042] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 10/31/2018] [Accepted: 11/27/2018] [Indexed: 12/22/2022]
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16
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Wang X, Zhang M, Liu H. LncRNA17A regulates autophagy and apoptosis of SH-SY5Y cell line as an in vitro model for Alzheimer's disease. Biosci Biotechnol Biochem 2019; 83:609-621. [PMID: 30652945 DOI: 10.1080/09168451.2018.1562874] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Considerable evidence suggest that a variety of Long-non-coding RNAs (LncRNAs) are widely implicated in several neurodegenerative disorders. The present study aims to investigate the regulatory effect of LncRNA 17A in an in vitro model of Alzheimer's disease (AD). AD cell model was established by treating the SH-SY5Y cells with amyloid β peptide 1-42, and then the cells were transfected with 17A shRNA and pcDNA-17A. Apoptosis, migration, invasion and ELISA assays were performed to investigate the effect of differentiated 17A expression level on AD cell line. It was determined that 17A-overexpressing promotes autophagy, induces neurodegenration and deactivates GABAB signaling. In conclusion, our results demonstrated that the dysregulation of LncRNA 17A was involved in cellular functions and biological processes of neuroblastoma cells in an AD cell model, shedding light on the diagnostic value and therapeutic potential of LncRNA 17A for AD intervention.
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Affiliation(s)
- Xinhua Wang
- a Department of Neurology , The Fifth Affiliated Hospital of Zhengzhou University , Zhengzhou , Henan Province , China
| | - Min Zhang
- a Department of Neurology , The Fifth Affiliated Hospital of Zhengzhou University , Zhengzhou , Henan Province , China
| | - Hengfang Liu
- a Department of Neurology , The Fifth Affiliated Hospital of Zhengzhou University , Zhengzhou , Henan Province , China
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17
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Reyes-Marin KE, Nuñez A. Seizure susceptibility in the APP/PS1 mouse model of Alzheimer's disease and relationship with amyloid β plaques. Brain Res 2017; 1677:93-100. [PMID: 28963050 DOI: 10.1016/j.brainres.2017.09.026] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 09/21/2017] [Accepted: 09/22/2017] [Indexed: 11/17/2022]
Abstract
Alzheimer's disease is a common age associated neurodegenerative disorder associated with an elevated risk of seizures that may be fundamentally connected to cognitive dysfunction. We used 4-9month-old mice of the APP/PS1 mouse model of Alzheimer's disease to study the presence of epileptiform-like discharges and to establish if the amyloid-β plaques affect their generation. The EEG of the APP/PS1 transgenic mice revealed a higher incidence of epileptiform-like discharges i.e. seizure events (interictal spikes, sharp waves, or polyspikes) than in the controls. Also, APP/PS1 mice showed a lower latency to evoke seizure events than in the control animals when pentylenetetrazole (60mg/kg; i.p.) was injected. Moreover, physostigmine injection (1mg/kg; i.p.) also increased the frequency of spontaneous epileptiform-like discharges in the APP/PS1 mice. We also found a correlation between the frequency of epileptiform-like discharges and the number of amyloid-β plaques. Application of N-(2-chloroethyl)-N-ethyl-bromobenzylamine (50mg/kg) generated amyloid-β plaques in the cortex and seizure activity appeared. Taken together, these data indicate that deposits of amyloid-β plaques may be responsible for the epileptiform-like discharges recorded in the APP/PS1 mice and could be responsible for the elevated risk for seizures of Alzheimer's patients.
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Affiliation(s)
- Karen E Reyes-Marin
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Angel Nuñez
- Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.
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18
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Towards a Better Understanding of GABAergic Remodeling in Alzheimer's Disease. Int J Mol Sci 2017; 18:ijms18081813. [PMID: 28825683 PMCID: PMC5578199 DOI: 10.3390/ijms18081813] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 08/16/2017] [Accepted: 08/17/2017] [Indexed: 12/18/2022] Open
Abstract
γ-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the vertebrate brain. In the past, there has been a major research drive focused on the dysfunction of the glutamatergic and cholinergic neurotransmitter systems in Alzheimer’s disease (AD). However, there is now growing evidence in support of a GABAergic contribution to the pathogenesis of this neurodegenerative disease. Previous studies paint a complex, convoluted and often inconsistent picture of AD-associated GABAergic remodeling. Given the importance of the GABAergic system in neuronal function and homeostasis, in the maintenance of the excitatory/inhibitory balance, and in the processes of learning and memory, such changes in GABAergic function could be an important factor in both early and later stages of AD pathogenesis. Given the limited scope of currently available therapies in modifying the course of the disease, a better understanding of GABAergic remodeling in AD could open up innovative and novel therapeutic opportunities.
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19
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Genome-wide screen for differentially methylated long noncoding RNAs identifies Esrp2 and lncRNA Esrp2-as regulated by enhancer DNA methylation with prognostic relevance for human breast cancer. Oncogene 2017; 36:6446-6461. [PMID: 28759043 PMCID: PMC5701091 DOI: 10.1038/onc.2017.246] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 06/05/2017] [Accepted: 06/08/2017] [Indexed: 12/14/2022]
Abstract
The majority of long noncoding RNAs (lncRNAs) is still poorly characterized with respect to function, interactions with protein-coding genes, and mechanisms that regulate their expression. As for protein-coding RNAs, epigenetic deregulation of lncRNA expression by alterations in DNA methylation might contribute to carcinogenesis. To provide genome-wide information on lncRNAs aberrantly methylated in breast cancer we profiled tumors of the C3(1) SV40TAg mouse model by MCIp-seq (Methylated CpG Immunoprecipitation followed by sequencing). This approach detected 69 lncRNAs differentially methylated between tumor tissue and normal mammary glands, with 26 located in antisense orientation of a protein-coding gene. One of the hypomethylated lncRNAs, 1810019D21Rik (now called Esrp2-antisense (as)) was identified in proximity to the epithelial splicing regulatory protein 2 (Esrp2) that is significantly elevated in C3(1) tumors. ESRPs were shown previously to have a dual role in carcinogenesis. Both gain and loss have been associated with poor prognosis in human cancers, but the mechanisms regulating expression are not known. In-depth analyses indicate that coordinate overexpression of Esrp2 and Esrp2-as inversely correlates with DNA methylation. Luciferase reporter gene assays support co-expression of Esrp2 and the major short Esrp2-as variant from a bidirectional promoter, and transcriptional regulation by methylation of a proximal enhancer. Ultimately, this enhancer-based regulatory mechanism provides a novel explanation for tissue-specific expression differences and upregulation of Esrp2 during carcinogenesis. Knockdown of Esrp2-as reduced Esrp2 protein levels without affecting mRNA expression and resulted in an altered transcriptional profile associated with extracellular matrix (ECM), cell motility and reduced proliferation, whereas overexpression enhanced proliferation. Our findings not only hold true for the murine tumor model, but led to the identification of an unannotated human homolog of Esrp2-as which is significantly upregulated in human breast cancer and associated with poor prognosis.
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20
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Li Y, Sun H, Chen Z, Xu H, Bu G, Zheng H. Implications of GABAergic Neurotransmission in Alzheimer's Disease. Front Aging Neurosci 2016; 8:31. [PMID: 26941642 PMCID: PMC4763334 DOI: 10.3389/fnagi.2016.00031] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/08/2016] [Indexed: 01/02/2023] Open
Abstract
Alzheimer's disease (AD) is characterized pathologically by the deposition of β-amyloid peptides (Aβ) and the accumulation of neurofibrillary tangles (NFTs) composed of hyper-phosphorylated tau. Regardless of the pathological hallmarks, synaptic dysfunction is widely accepted as a causal event in AD. Of the two major types of synapses in the central nervous system (CNS): glutamatergic and GABAergic, which provide excitatory and inhibitory outputs respectively, abundant data implicate an impaired glutamatergic system during disease progression. However, emerging evidence supports the notion that disrupted default neuronal network underlies impaired memory, and that alterations of GABAergic circuits, either plays a primary role or as a compensatory response to excitotoxicity, may also contribute to AD by disrupting the overall network function. The goal of this review is to provide an overview of the involvement of Aβ, tau and apolipoprotein E4 (apoE4), the major genetic risk factor in late-onset AD (LOAD), in GABAergic neurotransmission and the potential of modulating the GABAergic function as AD therapy.
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Affiliation(s)
- Yanfang Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, China
| | - Hao Sun
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, China
| | - Zhicai Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, China
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen UniversityXiamen, China; Neurodegenerative Disease Research Program, Sanford-Burnham Medical Research InstituteLa Jolla, CA, USA
| | - Guojun Bu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen UniversityXiamen, China; Department of Neuroscience, Mayo ClinicJacksonville, FL, USA
| | - Hui Zheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen UniversityXiamen, China; The Interdepartmental Program of Translational Biology and Molecular Medicine, Huffington Center on Aging, Baylor College of MedicineHouston, TX, USA
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21
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Prager EM, Bergstrom HC, Wynn GH, Braga MFM. The basolateral amygdala γ-aminobutyric acidergic system in health and disease. J Neurosci Res 2015; 94:548-67. [PMID: 26586374 DOI: 10.1002/jnr.23690] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/01/2015] [Accepted: 10/18/2015] [Indexed: 01/13/2023]
Abstract
The brain comprises an excitatory/inhibitory neuronal network that maintains a finely tuned balance of activity critical for normal functioning. Excitatory activity in the basolateral amygdala (BLA), a brain region that plays a central role in emotion and motivational processing, is tightly regulated by a relatively small population of γ-aminobutyric acid (GABA) inhibitory neurons. Disruption in GABAergic inhibition in the BLA can occur when there is a loss of local GABAergic interneurons, an alteration in GABAA receptor activation, or a dysregulation of mechanisms that modulate BLA GABAergic inhibition. Disruptions in GABAergic control of the BLA emerge during development, in aging populations, or after trauma, ultimately resulting in hyperexcitability. BLA hyperexcitability manifests behaviorally as an increase in anxiety, emotional dysregulation, or development of seizure activity. This Review discusses the anatomy, development, and physiology of the GABAergic system in the BLA and circuits that modulate GABAergic inhibition, including the dopaminergic, serotonergic, noradrenergic, and cholinergic systems. We highlight how alterations in various neurotransmitter receptors, including the acid-sensing ion channel 1a, cannabinoid receptor 1, and glutamate receptor subtypes, expressed on BLA interneurons, modulate GABAergic transmission and how defects of these systems affect inhibitory tonus within the BLA. Finally, we discuss alterations in the BLA GABAergic system in neurodevelopmental (autism/fragile X syndrome) and neurodegenerative (Alzheimer's disease) diseases and after the development of epilepsy, anxiety, and traumatic brain injury. A more complete understanding of the intrinsic excitatory/inhibitory circuit balance of the amygdala and how imbalances in inhibitory control contribute to excessive BLA excitability will guide the development of novel therapeutic approaches in neuropsychiatric diseases.
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Affiliation(s)
- Eric M Prager
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services, University of the Health Sciences, Bethesda, Maryland
| | | | - Gary H Wynn
- Center for the Study of Traumatic Stress, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Program in Neuroscience, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Maria F M Braga
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services, University of the Health Sciences, Bethesda, Maryland.,Center for the Study of Traumatic Stress, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Program in Neuroscience, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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22
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Vulnerability of calbindin, calretinin and parvalbumin in a transgenic/knock-in APPswe/PS1dE9 mouse model of Alzheimer disease together with disruption of hippocampal neurogenesis. Exp Gerontol 2015; 69:176-88. [DOI: 10.1016/j.exger.2015.06.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 06/16/2015] [Accepted: 06/18/2015] [Indexed: 11/19/2022]
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23
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Mizukami K, Akatsu H, Abrahamson EE, Mi Z, Ikonomovic MD. Immunohistochemical analysis of hippocampal butyrylcholinesterase: Implications for regional vulnerability in Alzheimer's disease. Neuropathology 2015; 36:135-45. [PMID: 26293308 DOI: 10.1111/neup.12241] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 07/27/2015] [Accepted: 07/27/2015] [Indexed: 11/28/2022]
Abstract
Studies of acetylcholine degrading enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in Alzheimer's disease (AD) have suggested their potential role in the development of fibrillar amyloid-β (Aβ) plaques (amyloid plaques). A recent genome-wide association study analysis identified a novel association between genetic variations in the BCHE locus and amyloid burden. We studied BChE immunoreactivity in hippocampal tissue sections from AD and control cases, and examined its relationship with amyloid plaques, neurofibrillary tangles (NFT), dystrophic neurites (DN) and neuropil threads (NT). Compared to controls, AD cases had greater BChE immunoreactivity in hippocampal neurons and neuropils in CA2/3, but not in the CA1, CA4 and dentate gyrus. The majority of amyloid plaques (> 80%, using a pan-amyloid marker X-34) contained discrete neuritic clusters which were dual-labeled with antibodies against BChE and phosphorylated tau (clone AT8). There was no association between overall regional BChE immunoreaction intensity and amyloid plaque burden. In contrast to previous reports, BChE was localized in only a fraction (~10%) of classic NFT (positive for X-34). A similar proportion of BChE-immunoreactive pyramidal cells were AT8 immunoreactive. Greater NFT and DN loads were associated with greater BChE immunoreaction intensity in CA2/3, but not in CA1, CA4 and dentate gyrus. Our results demonstrate that in AD hippocampus, BChE accumulates in neurons and plaque-associated neuritic clusters, but only in a small proportion of NFT. The association between greater neurofibrillary pathology burden and markedly increased BChE immunoreactivity, observed selectively in CA2/3 region, could reflect a novel compensatory mechanism. Since CA2/3 is generally considered more resistant to AD pathology, BChE upregulation could impact the cholinergic modulation of glutamate neurotransmission to prevent/reduce neuronal excitotoxicity in AD hippocampus.
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Affiliation(s)
- Katsuyoshi Mizukami
- Faculty of Health and Sport Sciences, Tsukuba, Japan.,Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Hiroyasu Akatsu
- Department of Community-based Medicine, Nagoya City University Graduate School of Medicine, Nagoya, Japan.,Choju Medical Institute, Fukushimura Hospital, Toyohashi, Japan
| | - Eric E Abrahamson
- Departments of Neurology, University of Pittsburgh, Pittsburgh, USA.,Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, USA
| | - Zhiping Mi
- Departments of Neurology, University of Pittsburgh, Pittsburgh, USA
| | - Milos D Ikonomovic
- Departments of Neurology, University of Pittsburgh, Pittsburgh, USA.,Psychiatry, University of Pittsburgh, Pittsburgh, USA.,Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, USA
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24
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Nava-Mesa MO, Jiménez-Díaz L, Yajeya J, Navarro-Lopez JD. GABAergic neurotransmission and new strategies of neuromodulation to compensate synaptic dysfunction in early stages of Alzheimer's disease. Front Cell Neurosci 2014; 8:167. [PMID: 24987334 PMCID: PMC4070063 DOI: 10.3389/fncel.2014.00167] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 06/02/2014] [Indexed: 01/06/2023] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by cognitive decline, brain atrophy due to neuronal and synapse loss, and formation of two pathological lesions: extracellular amyloid plaques, composed largely of amyloid-beta peptide (Aβ), and neurofibrillary tangles formed by intracellular aggregates of hyperphosphorylated tau protein. Lesions mainly accumulate in brain regions that modulate cognitive functions such as the hippocampus, septum or amygdala. These brain structures have dense reciprocal glutamatergic, cholinergic, and GABAergic connections and their relationships directly affect learning and memory processes, so they have been proposed as highly susceptible regions to suffer damage by Aβ during AD course. Last findings support the emerging concept that soluble Aβ peptides, inducing an initial stage of synaptic dysfunction which probably starts 20–30 years before the clinical onset of AD, can perturb the excitatory–inhibitory balance of neural circuitries. In turn, neurotransmission imbalance will result in altered network activity that might be responsible of cognitive deficits in AD. Therefore, Aβ interactions on neurotransmission systems in memory-related brain regions such as amygdaloid complex, medial septum or hippocampus are critical in cognitive functions and appear as a pivotal target for drug design to improve learning and dysfunctions that manifest with age. Since treatments based on glutamatergic and cholinergic pharmacology in AD have shown limited success, therapies combining modulators of different neurotransmission systems including recent findings regarding the GABAergic system, emerge as a more useful tool for the treatment, and overall prevention, of this dementia. In this review, focused on inhibitory systems, we will analyze pharmacological strategies to compensate neurotransmission imbalance that might be considered as potential therapeutic interventions in AD.
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Affiliation(s)
| | - Lydia Jiménez-Díaz
- Neurophysiology and Behavior Lab, Centro Regional de Investigaciones Biomédicas, School of Medicine of Ciudad Real, University of Castilla-La Mancha Ciudad Real, Spain
| | - Javier Yajeya
- Department of Physiology and Pharmacology, University of Salamanca Salamanca, Spain
| | - Juan D Navarro-Lopez
- Neurophysiology and Behavior Lab, Centro Regional de Investigaciones Biomédicas, School of Medicine of Ciudad Real, University of Castilla-La Mancha Ciudad Real, Spain
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Giannopoulos PF, Joshi YB, Chu J, Praticò D. The 12-15-lipoxygenase is a modulator of Alzheimer's-related tau pathology in vivo. Aging Cell 2013; 12:1082-90. [PMID: 23862663 DOI: 10.1111/acel.12136] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2013] [Indexed: 01/14/2023] Open
Abstract
12/15-lipoxygenase (12-15LO) is a lipid-peroxidizing enzyme widely expressed in the central nervous system where it has been involved in the neurobiology of Alzheimer's disease (AD) because it modulates amyloid beta (Aβ) and APP processing. However, its biological effect on tau protein is unknown. We investigated the effect of 12-15LO on tau levels and metabolism in vivo and in vitro and the mechanism involved by using genetic and pharmacologic approaches. While no significant differences were observed in the levels of total tau for both groups, compared with controls, Tg2576 mice overexpressing 12-15LO had elevated levels of phosphorylated tau at two specific epitopes, Ser 202/Thr 205 and Ser 396. In vitro and in vivo studies show that 12-15LO modulates tau metabolism specifically via the cdk5 kinase pathway. Associated with these changes were biochemical markers of synaptic pathology. Finally, 12-15LO-dependent alteration of tau metabolism was independent from an effect on Aβ. Our findings reveal a novel pathway by which 12-15LO modulates endogenous tau metabolism making this protein an appealing pharmacologic target for treatment of AD and related tauopathies.
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Affiliation(s)
- Phillip F. Giannopoulos
- Center for Translational Medicine and Department of Pharmacology; Temple University School of Medicine; Philadelphia PA 19140 USA
| | - Yash B. Joshi
- Center for Translational Medicine and Department of Pharmacology; Temple University School of Medicine; Philadelphia PA 19140 USA
| | - Jin Chu
- Center for Translational Medicine and Department of Pharmacology; Temple University School of Medicine; Philadelphia PA 19140 USA
| | - Domenico Praticò
- Center for Translational Medicine and Department of Pharmacology; Temple University School of Medicine; Philadelphia PA 19140 USA
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Chu J, Li JG, Ceballos-Diaz C, Golde T, Praticò D. The influence of 5-lipoxygenase on Alzheimer's disease-related tau pathology: in vivo and in vitro evidence. Biol Psychiatry 2013; 74:321-8. [PMID: 23352590 PMCID: PMC3726558 DOI: 10.1016/j.biopsych.2012.12.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 12/18/2012] [Accepted: 12/18/2012] [Indexed: 01/15/2023]
Abstract
BACKGROUND Intracellular deposition of tau protein is a hallmark lesion of Alzheimer's disease. Although it is known this event is secondary to excessive tau phosphorylation, the mechanisms involved remain unknown. We previously reported that the enzyme 5-Lipoxygenase (5LO) acts as a modulator of Aβ peptides formation in vivo, and here we investigate its influence on tau protein. METHODS Tg2576 mice overexpressing neuronal 5LO were generated and its contribution to endogenous tau levels and metabolism investigated. RESULTS Although no differences were noted in the levels of total tau for both groups, compared with controls, Tg2576 mice overexpressing 5LO had a significant increase in the phosphorylation state of tau at S396 and S396/S404, as recognized by the antibodies PHF-13 and PHF-1, respectively. By contrast, no phosphorylation changes were observed in other tau epitopes. This increase was associated with a significant elevation in cyclin dependent kinase-5 but not other kinases that have been involved in tau phosphorylation. Additionally, mice overexpressing 5LO had biochemical evidence of altered synaptic integrity because they manifested a reduction in PSD-95, synaptophysin and MAP2. CONCLUSIONS This study demonstrates a new role for 5LO in regulating endogenous tau metabolism in the central nervous system and supports the hypothesis that its pharmacologic inhibition could be beneficial for Alzheimer's disease-related tau neuropathology.
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Affiliation(s)
- Jin Chu
- Centre for Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania, USA
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Mizukami K, Abrahamson EE, Mi Z, Ishikawa M, Watanabe K, Kinoshita S, Asada T, Ikonomovic MD. Immunohistochemical analysis of ubiquilin-1 in the human hippocampus: association with neurofibrillary tangle pathology. Neuropathology 2013; 34:11-8. [PMID: 23869942 DOI: 10.1111/neup.12055] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 06/23/2013] [Accepted: 06/24/2013] [Indexed: 12/28/2022]
Abstract
This post mortem immunohistochemical study examined the localization and distribution of ubiquilin-1 (UBL), a shuttle protein which interacts with ubiquitin and the proteasome, in the hippocampus from Alzheimer's disease (AD) dementia cases, and age-matched cases without dementia. In Braak stages 0-I-II cases, UBL immunoreactivity was detected in a dense fiber network in the neuropil, and in the cell cytoplasm and nucleoplasm of neurons in Cornu Ammonis (CA) fields and dentate gyrus granular neurons. In Braak stages III-IV and V-VI cases, UBL immunoreactivity was reduced in the neuropil and in the cytoplasm of the majority of CA1 neurons; some CA1 pyramidal neurons and the majority of CA2/3 pyramidal, CA4 multipolar, and dentate granular neurons had markedly increased UBL immunoreactivity in the nucleoplasm. Dual immunofluorescence analysis of UBL and antibody clone AT8 revealed co-localization most frequently in CA1 pyramidal neurons in Braak stage III-IV and V-VI cases. Further processing using the pan-amyloid marker X-34 revealed prominent UBL/X-34 dual labeling of extracellular NFT confined to the CA1/subiculum in Braak stage V-VI cases. Our results demonstrate that in AD hippocampus, early NFT changes are associated with neuronal up-regulation of UBL in nucleoplasm, or its translocation from the cytoplasm to the nucleus. The perseverance of UBL changes in CA2/3, CA4 and dentate gyrus, generally considered as more resistant to NFT pathology, but not in the CA1, may mark a compensatory, potentially protective response to increased tau phosphorylation in hippocampal neurons; the failure of such a response may contribute to neuronal degeneration in end-stage AD.
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Affiliation(s)
- Katsuyoshi Mizukami
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tokyo, Japan
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Repetitive Mild Traumatic Brain Injury Augments Tau Pathology and Glial Activation in Aged hTau Mice. J Neuropathol Exp Neurol 2013; 72:137-51. [DOI: 10.1097/nen.0b013e3182814cdf] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Pascual B, Prieto E, Arbizu J, Marti-Climent JM, Peñuelas I, Quincoces G, Zarauza R, Pappatà S, Masdeu JC. Decreased carbon-11-flumazenil binding in early Alzheimer's disease. ACTA ACUST UNITED AC 2012; 135:2817-25. [PMID: 22961552 DOI: 10.1093/brain/aws210] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Neuronal loss in Alzheimer's disease, a better correlate of cognitive impairment than amyloid deposition, is currently gauged by the degree of regional atrophy. However, functional markers, such as GABA(A) receptor density, a marker of neuronal integrity, could be more sensitive. In post-mortem hippocampus, GABA(A) messenger RNA expression is reduced even in mild cognitive impairment. We measured whole-brain GABA(A) binding potential in vivo using [(11)C]-flumazenil positron emission tomography and compared GABA(A) binding with metabolic and volumetric measurements. For this purpose, we studied 12 subjects, six patients with early Alzheimer's disease and six healthy controls, with [(11)C]-flumazenil and [(18)F]-fluorodeoxyglucose positron emission tomography, as well as with high-resolution magnetic resonance imaging. Data were evaluated with both voxel-based parametric methods and volume of interest methods. We found that in early Alzheimer's disease, with voxel-based analysis, [(11)C]-flumazenil binding was decreased in infero-medial temporal cortex, retrosplenial cortex and posterior perisylvian regions. Inter-group differences reached corrected significance when using an arterial input function. Metabolism measured with positron emission tomography and volumetric measurements obtained with magnetic resonance imaging showed changes in regions affected in early Alzheimer's disease, but, unlike with [(11)C]-flumazenil binding and probably due to sample size, the voxel-based findings failed to reach corrected significance in any region of the brain. With volume of interest analysis, hippocampi and posterior cingulate gyrus showed decreased [(11)C]-flumazenil binding. In addition, [(11)C]-flumazenil hippocampal binding correlated with memory performance. Remarkably, [(11)C]-flumazenil binding was decreased precisely in the regions showing the greatest degree of neuronal loss in post-mortem studies of early Alzheimer's disease. From these data, we conclude that [(11)C]-flumazenil binding could be a useful marker of neuronal loss in early Alzheimer's disease.
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Affiliation(s)
- Belen Pascual
- Neuroscience Division, Centre for Applied Medical Research, University of Navarra, Pamplona, 31008, Spain.
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Loss of functional GABA(A) receptors in the Alzheimer diseased brain. Proc Natl Acad Sci U S A 2012; 109:10071-6. [PMID: 22691495 DOI: 10.1073/pnas.1204606109] [Citation(s) in RCA: 181] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The cholinergic and glutamatergic neurotransmission systems are known to be severely disrupted in Alzheimer's disease (AD). GABAergic neurotransmission, in contrast, is generally thought to be well preserved. Evidence from animal models and human postmortem tissue suggest GABAergic remodeling in the AD brain. Nevertheless, there is no information on changes, if any, in the electrophysiological properties of human native GABA receptors as a consequence of AD. To gain such information, we have microtransplanted cell membranes, isolated from temporal cortices of control and AD brains, into Xenopus oocytes, and recorded the electrophysiological activity of the transplanted GABA receptors. We found an age-dependent reduction of GABA currents in the AD brain. This reduction was larger when the AD membranes were obtained from younger subjects. We also found that GABA currents from AD brains have a faster rate of desensitization than those from non-AD brains. Furthermore, GABA receptors from AD brains were slightly, but significantly, less sensitive to GABA than receptors from non-AD brains. The reduction of GABA currents in AD was associated with reductions of mRNA and protein of the principal GABA receptor subunits normally present in the temporal cortex. Pairwise analysis of the transcripts within control and AD groups and analyses of the proportion of GABA receptor subunits revealed down-regulation of α1 and γ2 subunits in AD. In contrast, the proportions of α2, β1, and γ1 transcripts were up-regulated in the AD brains. Our data support a functional remodeling of GABAergic neurotransmission in the human AD brain.
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Rissman RA, Mobley WC. Implications for treatment: GABAA receptors in aging, Down syndrome and Alzheimer's disease. J Neurochem 2011; 117:613-22. [PMID: 21388375 DOI: 10.1111/j.1471-4159.2011.07237.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In addition to progressive dementia, Alzheimer's disease (AD) is characterized by increased incidence of seizure activity. Although originally discounted as a secondary process occurring as a result of neurodegeneration, more recent data suggest that alterations in excitatory-inhibitory (E/I) balance occur in AD and may be a primary mechanism contributing AD cognitive decline. In this study, we discuss relevant research and reports on the GABA(A) receptor in developmental disorders, such as Down syndrome, in healthy aging, and highlight documented aberrations in the GABAergic system in AD. Stressing the importance of understanding the subunit composition of individual GABA(A) receptors, investigations demonstrate alterations of particular GABA(A) receptor subunits in AD, but overall sparing of the GABAergic system. In this study, we review experimental data on the GABAergic system in the pathobiology of AD and discuss relevant therapeutic implications. When developing AD therapeutics that modulate GABA it is important to consider how E/I balance impacts AD pathogenesis and the relationship between seizure activity and cognitive decline.
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Affiliation(s)
- Robert A Rissman
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093-0624, USA.
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Age-dependent impairment of cognitive and synaptic function in the htau mouse model of tau pathology. J Neurosci 2009; 29:10741-9. [PMID: 19710325 DOI: 10.1523/jneurosci.1065-09.2009] [Citation(s) in RCA: 244] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A hallmark feature of Alzheimer's disease pathology is the presence of neurofibrillary tangles (NFTs), which are intracellular aggregates of conformationally abnormal and hyperphosphorylated tau. The presence of NFTs in the forebrain is associated with impairments of cognitive function, supporting a central role for tau in dementia. The significance of the accumulation of NFTs for neuronal and cognitive function is still obscure. It is possible that NFTs disrupt synaptic transmission and plasticity, leading to memory deficits and cognitive malfunction. To elucidate the relationship between the development of tau pathology and synaptic and cognitive functions, we performed behavioral tests and electrophysiological experiments in the htau mouse. Here we report age-dependent cognitive and physiological impairments in htau mice that preceded neurodegeneration. Twelve-month-old htau mice with moderate tau pathology, but not 4-month-old mice with early-stage tau pathology, presented cognitive deficits in an object recognition memory task in which the visual recognition memory of a novel object was disrupted. Moreover, only 12-month-old htau mice exhibit spatial memory deficits, as indicated by the impaired performance in the Morris water maze. In addition, we report that basal synaptic transmission and induction of long-term potentiation with high-frequency stimulation, but not theta burst stimulation, is perturbed in hippocampal CA1 region of old but not young htau mice. Our results suggest that tau pathology may underlie an age-dependent learning impairment through disruption of synaptic function.
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