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Maitre M, Jeltsch-David H, Okechukwu NG, Klein C, Patte-Mensah C, Mensah-Nyagan AG. Myelin in Alzheimer's disease: culprit or bystander? Acta Neuropathol Commun 2023; 11:56. [PMID: 37004127 PMCID: PMC10067200 DOI: 10.1186/s40478-023-01554-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/20/2023] [Indexed: 04/03/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder with neuronal and synaptic losses due to the accumulation of toxic amyloid β (Αβ) peptide oligomers, plaques, and tangles containing tau (tubulin-associated unit) protein. While familial AD is caused by specific mutations, the sporadic disease is more common and appears to result from a complex chronic brain neuroinflammation with mitochondriopathies, inducing free radicals' accumulation. In aged brain, mutations in DNA and several unfolded proteins participate in a chronic amyloidosis response with a toxic effect on myelin sheath and axons, leading to cognitive deficits and dementia. Αβ peptides are the most frequent form of toxic amyloid oligomers. Accumulations of misfolded proteins during several years alters different metabolic mechanisms, induce chronic inflammatory and immune responses with toxic consequences on neuronal cells. Myelin composition and architecture may appear to be an early target for the toxic activity of Aβ peptides and others hydrophobic misfolded proteins. In this work, we describe the possible role of early myelin alterations in the genesis of neuronal alterations and the onset of symptomatology. We propose that some pathophysiological and clinical forms of the disease may arise from structural and metabolic disorders in the processes of myelination/demyelination of brain regions where the accumulation of non-functional toxic proteins is important. In these forms, the primacy of the deleterious role of amyloid peptides would be a matter of questioning and the initiating role of neuropathology would be primarily the fact of dysmyelination.
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Affiliation(s)
- Michel Maitre
- Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques, Fédération de Médecine Translationnelle de Strasbourg (FMTS), INSERM U1119, Université de Strasbourg, Bâtiment CRBS de la Faculté de Médecine, 1 rue Eugène Boeckel, Strasbourg, 67000, France.
| | - Hélène Jeltsch-David
- Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques, Fédération de Médecine Translationnelle de Strasbourg (FMTS), INSERM U1119, Université de Strasbourg, Bâtiment CRBS de la Faculté de Médecine, 1 rue Eugène Boeckel, Strasbourg, 67000, France
- Biotechnologie et signalisation cellulaire, UMR 7242 CNRS, Université de Strasbourg, 300 Boulevard Sébastien Brant CS 10413, Illkirch cedex, 67412, France
| | - Nwife Getrude Okechukwu
- Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques, Fédération de Médecine Translationnelle de Strasbourg (FMTS), INSERM U1119, Université de Strasbourg, Bâtiment CRBS de la Faculté de Médecine, 1 rue Eugène Boeckel, Strasbourg, 67000, France
| | - Christian Klein
- Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques, Fédération de Médecine Translationnelle de Strasbourg (FMTS), INSERM U1119, Université de Strasbourg, Bâtiment CRBS de la Faculté de Médecine, 1 rue Eugène Boeckel, Strasbourg, 67000, France
| | - Christine Patte-Mensah
- Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques, Fédération de Médecine Translationnelle de Strasbourg (FMTS), INSERM U1119, Université de Strasbourg, Bâtiment CRBS de la Faculté de Médecine, 1 rue Eugène Boeckel, Strasbourg, 67000, France
| | - Ayikoe-Guy Mensah-Nyagan
- Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques, Fédération de Médecine Translationnelle de Strasbourg (FMTS), INSERM U1119, Université de Strasbourg, Bâtiment CRBS de la Faculté de Médecine, 1 rue Eugène Boeckel, Strasbourg, 67000, France
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2
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Aria H, Rezaei M. Immunogenic cell death inducer peptides: A new approach for cancer therapy, current status and future perspectives. Biomed Pharmacother 2023; 161:114503. [PMID: 36921539 DOI: 10.1016/j.biopha.2023.114503] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 02/23/2023] [Accepted: 03/07/2023] [Indexed: 03/14/2023] Open
Abstract
Immunogenic Cell Death (ICD) is a type of cell death that kills tumor cells by stimulating the adaptive immune response against other tumor cells. ICD depends on the endoplasmic reticulum (ER) stress and the secretion of Damage-Associated Molecular Patterns (DAMP) by the dying tumor cell. DAMPs recruit innate immune cells such as Dendritic Cells (DC), triggering a cancer-specific immune response such as cytotoxic T lymphocytes (CTLs) to eliminate remaining cancer cells. ICD is accompanied by several hallmarks in dying cells, such as surface translocation of ER chaperones, calreticulin (CALR), and extracellular secretion of DAMPs such as high mobility group protein B1 (HMGB1) and adenosine triphosphate (ATP). Therapeutic peptides can kill bacteria and tumor cells thus affecting the immune system. They have high specificity and affinity for their targets, small size, appropriate cell membrane penetration, short half-life, and simple production processes. Peptides are interesting agents for immunomodulation since they may overcome the limitations of other therapeutics. Thus, the development of peptides affecting the TME and active antitumoral immunity has been actively pursued. On the other hand, several peptides have been recently identified to trigger ICD and anti-cancer responses. In the present review, we review previous studies on peptide-induced ICD, their mechanism, their targets, and markers. They include anti-microbial peptides (AMPs), cationic or mitochondrial targeting, checkpoint inhibitors, antiapoptotic inhibitors, and "don't eat me" inhibitor peptides. Also, peptides will be investigated potentially inducing ICD that is divided into ER stressors, ATPase inhibitors, and anti-microbial peptides.
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Affiliation(s)
- Hamid Aria
- Department of Immunology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Marzieh Rezaei
- Department of Immunology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
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3
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Mahan B, Tacail T, Lewis J, Elliott T, Habekost M, Turner S, Chung R, Moynier F. Exploring the K isotope composition of Göttingen minipig brain regions, and implications for Alzheimer's disease. Metallomics 2022; 14:mfac090. [PMID: 36416864 PMCID: PMC9764214 DOI: 10.1093/mtomcs/mfac090] [Citation(s) in RCA: 2] [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: 09/16/2022] [Accepted: 11/18/2022] [Indexed: 11/24/2022]
Abstract
Natural stable metal isotopes have shown utility in differentiation between healthy and diseased brain states (e.g. Alzheimer's disease, AD). While the AD brain accumulates some metals, it purges others, namely K (accompanied by increased serum K, suggesting brain-blood transferal). Here, K isotope compositions of Göttingen minipig brain regions for two AD models at midlife are reported. Results indicate heavy K isotope enrichment where amyloid beta (Aβ) accumulation is observed, and this enrichment correlates with relative K depletion. These results suggest preferential efflux of isotopically light K+ from the brain, a linkage between brain K concentrations and isotope compositions, and linkage to Aβ (previously shown to purge cellular brain K+). Brain K isotope compositions differ from that for serum and brain K is much more abundant than in serum, suggesting that changes in brain K may transfer a measurable K isotope excursion to serum, thereby generating an early AD biomarker.
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Affiliation(s)
- Brandon Mahan
- IsoTropics Geochemistry Lab, Earth and Environmental Science, James Cook University, Townsville, Queensland 4814, Australia
- Thermo Fisher Isotope Development Hub, Department of Earth and Planetary Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
- Department of Biomedical Research, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Theo Tacail
- Bristol Isotope Group, School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK
- Institute of Geosciences, Johannes Gutenberg University, Mainz 55099, Germany
| | - Jamie Lewis
- Bristol Isotope Group, School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK
| | - Tim Elliott
- Bristol Isotope Group, School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK
| | - Mette Habekost
- Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
- Center for Neuroscience, University of Copenhagen Faculty of Health and Medical Sciences, 2200 Copenhagen N, Denmark
| | - Simon Turner
- Thermo Fisher Isotope Development Hub, Department of Earth and Planetary Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Roger Chung
- Thermo Fisher Isotope Development Hub, Department of Earth and Planetary Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
- Department of Biomedical Research, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Frédéric Moynier
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, 75238 Paris, France
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4
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Wang X, Hu M, Xie Q, Geng C, Jin C, Ren W, Fan J, Ma T, Hu B. Amyloid β oligomers disrupt piriform cortical output via a serotonergic pathway. Neurobiol Aging 2022; 121:64-77. [DOI: 10.1016/j.neurobiolaging.2022.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 09/16/2022] [Accepted: 09/17/2022] [Indexed: 12/01/2022]
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Zhao S, Chen F, Wang D, Han W, Zhang Y, Yin Q. NLRP3 inflammasomes are involved in the progression of postoperative cognitive dysfunction: from mechanism to treatment. Neurosurg Rev 2020; 44:1815-1831. [PMID: 32918635 DOI: 10.1007/s10143-020-01387-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/25/2020] [Accepted: 09/03/2020] [Indexed: 12/15/2022]
Abstract
Postoperative cognitive dysfunction (POCD) involves patient memory and learning decline after surgery. POCD not only presents challenges for postoperative nursing and recovery but may also cause permanent brain damage for patients, including children and the aged, with vulnerable central nervous systems. Its occurrence is mainly influenced by surgical trauma, anesthetics, and the health condition of the patient. There is a lack of imaging and experimental diagnosis; therefore, patients can only be diagnosed by clinical observation, which may underestimate the morbidity, resulting in decreased treatment efficacy. Except for symptomatic support therapy, there is a relative lack of effective drugs specific for the treatment of POCD, because the precise mechanism of POCD remains to be determined. One current hypothesis is that postoperative inflammation promotes the progression of POCD. Accumulating research has indicated that overactivation of NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasomes contribute to the POCD progression, suggesting that targeting NLRP3 inflammasomes may be an effective therapy to treat POCD. In this review, we summarize recent studies and systematically describe the pathogenesis, treatment progression, and potential treatment options of targeting NLRP3 inflammasomes in POCD patients.
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Affiliation(s)
- Shuai Zhao
- Department of Anesthesiology, First Hospital of Jilin University, 71 Xinmin Avenue, Changchun, 130021, China
| | - Fan Chen
- Department of Neurosurgery, University of Medicine Greifswald, Greifswald, Germany
| | - Dunwei Wang
- Department of Anesthesiology, First Hospital of Jilin University, 71 Xinmin Avenue, Changchun, 130021, China
| | - Wei Han
- Department of Anesthesiology, First Hospital of Jilin University, 71 Xinmin Avenue, Changchun, 130021, China
| | - Yuan Zhang
- Department of Anesthesiology, First Hospital of Jilin University, 71 Xinmin Avenue, Changchun, 130021, China.
| | - Qiliang Yin
- Department of Oncology, First Hospital of Jilin University, Changchun, China.
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6
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Aceto G, Re A, Mattera A, Leone L, Colussi C, Rinaudo M, Scala F, Gironi K, Barbati SA, Fusco S, Green T, Laezza F, D'Ascenzo M, Grassi C. GSK3β Modulates Timing-Dependent Long-Term Depression Through Direct Phosphorylation of Kv4.2 Channels. Cereb Cortex 2020; 29:1851-1865. [PMID: 29790931 DOI: 10.1093/cercor/bhy042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 01/15/2018] [Accepted: 02/07/2018] [Indexed: 12/31/2022] Open
Abstract
Spike timing-dependent plasticity (STDP) is a form of activity-dependent remodeling of synaptic strength that underlies memory formation. Despite its key role in dictating learning rules in the brain circuits, the molecular mechanisms mediating STDP are still poorly understood. Here, we show that spike timing-dependent long-term depression (tLTD) and A-type K+ currents are modulated by pharmacological agents affecting the levels of active glycogen-synthase kinase 3 (GSK3) and by GSK3β knockdown in layer 2/3 of the mouse somatosensory cortex. Moreover, the blockade of A-type K+ currents mimics the effects of GSK3 up-regulation on tLTD and occludes further changes in synaptic strength. Pharmacological, immunohistochemical and biochemical experiments revealed that GSK3β influence over tLTD induction is mediated by direct phosphorylation at Ser-616 of the Kv4.2 subunit, a molecular determinant of A-type K+ currents. Collectively, these results identify the functional interaction between GSK3β and Kv4.2 channel as a novel mechanism for tLTD modulation providing exciting insight into the understanding of GSK3β role in synaptic plasticity.
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Affiliation(s)
- Giuseppe Aceto
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Agnese Re
- Institute of Cell Biology and Neurobiology, National Research Council, Rome, Italy
| | - Andrea Mattera
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Lucia Leone
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario A Gemelli, IRCCS, Rome, Italy
| | - Claudia Colussi
- Institute of Cell Biology and Neurobiology, National Research Council, Rome, Italy
| | - Marco Rinaudo
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Federico Scala
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Katia Gironi
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | | | - Salvatore Fusco
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario A Gemelli, IRCCS, Rome, Italy
| | - Thomas Green
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
| | - Fernanda Laezza
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
| | - Marcello D'Ascenzo
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario A Gemelli, IRCCS, Rome, Italy
| | - Claudio Grassi
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario A Gemelli, IRCCS, Rome, Italy
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7
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Chow LWC, Leung YM. The versatile Kv channels in the nervous system: actions beyond action potentials. Cell Mol Life Sci 2020; 77:2473-2482. [PMID: 31894358 PMCID: PMC11104815 DOI: 10.1007/s00018-019-03415-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 11/16/2019] [Accepted: 12/09/2019] [Indexed: 12/22/2022]
Abstract
Voltage-gated K+ (Kv) channel opening repolarizes excitable cells by allowing K+ efflux. Over the last two decades, multiple Kv functions in the nervous system have been found to be unrelated to or beyond the immediate control of excitability, such as shaping action potential contours or regulation of inter-spike frequency. These functions include neuronal exocytosis and neurite formation, neuronal cell death, regulation of astrocyte Ca2+, glial cell and glioma proliferation. Some of these functions have been shown to be independent of K+ conduction, that is, they suggest the non-canonical functions of Kv channels. In this review, we focus on neuronal or glial plasmalemmal Kv channel functions which are unrelated to shaping action potentials or immediate control of excitability. Similar functions in other cell types will be discussed to some extent in appropriate contexts.
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Affiliation(s)
- Louis W C Chow
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau, China
- UNIMED Medical Institute, Hong Kong, China
- Organisation for Oncology and Translational Research, Hong Kong, China
| | - Yuk- Man Leung
- Department of Physiology, China Medical University, Taichung, 40402, Taiwan.
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8
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Vicente MC, Humphrey CM, Gargaglioni LH, Ostrowski TD. Decreased excitability of locus coeruleus neurons during hypercapnia is exaggerated in the streptozotocin-model of Alzheimer's disease. Exp Neurol 2020; 328:113250. [PMID: 32088169 DOI: 10.1016/j.expneurol.2020.113250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 02/04/2020] [Accepted: 02/17/2020] [Indexed: 10/25/2022]
Abstract
The locus coeruleus (LC) is a pontine nucleus important for respiratory control and central chemoreception. It is affected in Alzheimer's disease (AD) and alteration of LC cell function may account for respiratory problems observed in AD patients. In the current study, we tested the electrophysiological properties and CO2/pH sensitivity of LC neurons in a model for AD. Sporadic AD was induced in rats by intracerebroventricular injection of 2 mg/kg streptozotocin (STZ), which induces behavioral and molecular impairments found in AD. LC neurons were recorded using the patch clamp technique and tested for responses to CO2 (10% CO2, pH = 7.0). The majority (~60%) of noradrenergic LC neurons in adult rats were inhibited by CO2 exposure as indicated by a significant decrease in action potential (AP) discharge to step depolarizations. The STZ-AD rat model had a greater sensitivity to CO2 than controls. The increased CO2-sensitivity was demonstrated by a significantly stronger inhibition of activity during hypercapnia that was in part due to hyperpolarization of the resting membrane potential. Reduction of AP discharge in both groups was generally accompanied by lower LC network activity, depolarized AP threshold, increased AP repolarization, and increased current through a subpopulation of voltage-gated K+ channels (KV). The latter was indicated by enhanced transient KV currents particularly in the STZ-AD group. Interestingly, steady-state KV currents were reduced under hypercapnia, a change that would favor enhanced AP discharge. However, the collective response of most LC neurons in adult rats, and particularly those in the STZ-AD group, was inhibited by CO2.
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Affiliation(s)
- Mariane C Vicente
- Department of Physiology, Kirksville College of Osteopathic Medicine, A.T. Still University of Health Sciences, Kirksville, MO, USA; Department of Animal Morphology and Physiology, Sao Paulo State University-UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Chuma M Humphrey
- Department of Biology, Truman State University, Kirksville, MO, USA
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, Sao Paulo State University-UNESP/FCAV at Jaboticabal, SP, Brazil
| | - Tim D Ostrowski
- Department of Physiology, Kirksville College of Osteopathic Medicine, A.T. Still University of Health Sciences, Kirksville, MO, USA.
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Chen M, Chen Y, Wang X, Zhou Y. Quantitative determination of talatisamine and its pharmacokinetics and bioavailability in mouse plasma by UPLC-MS/MS. J Chromatogr B Analyt Technol Biomed Life Sci 2019; 1124:180-187. [PMID: 31207562 DOI: 10.1016/j.jchromb.2019.06.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 05/17/2019] [Accepted: 06/07/2019] [Indexed: 11/17/2022]
Abstract
Talatisamine, as the efficacy ingredient of Aconitum, was known as a novel specific blocker for the delayed rectifier K+ channels in rat hippocampal neurons. In this study, a rapid, selective and reproducible UPLC-MS/MS separation method was established and fully validated for the quantitative determination of talatisamine levels in ICR (Institute of Cancer Research) mouse blood. A total of 24 healthy male ICR mice were divided into four groups that was administered talatisamine via intravenous at a dose of 1 mg/kg and oral administration of three doses (2, 4, 8 mg/kg). All blood samples were protein precipitate by using acetonitrile with an internal standard (IS) deltaline. The effective chromatographic separation was carried out through an UPLC BEH C18 analytical column (2.1 mm × 50 mm, 1.7 μm) with an initial mobile phase that consisted of acetonitrile and 10 mmol/L ammonium acetate aqueous solution (containing 0.1% formic acid) with a gradient elution pumped at a flow rate of 0.4 mL/min. Also, an electrospray ionization (ESI) was applied to quantify the talatisamine in the positive ions mode. The method validation demonstrated good linearity over the range of 1-1000 ng/mL (r2 ≥ 0.9993) for talatisamine in mouse blood with a lower limit of quantification (LLOQ) at 1 ng/mL. The accuracy values of the method were within 89.4% to 113.3%, and the matrix effects were between 103.2% and 106.3%. The mean extraction recoveries for talatisamine obtained from four concentrations of QC blood samples were exceeded 71.7%, and the relative standard deviation (RSD) both of intra- and inter-day precision values for replicate quality control samples did not exceed 15% respectively for all analytes during the assay validation. This method was successfully applied to the evaluation of the pharmacokinetic of talatisamine, regardless of intragastric or intravenous administration in mice. Based on the pharmacokinetics data, the bioavailability of talatisamine in mice was >65.0% after oral administration, exhibiting an excellent oral absorption.
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Affiliation(s)
- Mengchun Chen
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Yijie Chen
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Xianqin Wang
- Analytical and Testing Centre, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China.
| | - Yunfang Zhou
- The Laboratory of Clinical Pharmacy, The People's Hospital of Lishui, Lishui 323000, China.
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Yan W, Zhang M, Yu Y, Yi X, Guo T, Hu H, Sun Q, Chen M, Xiong H, Chen L. Blockade of voltage-gated potassium channels ameliorates diabetes-associated cognitive dysfunction in vivo and in vitro. Exp Neurol 2019; 320:112988. [PMID: 31254519 DOI: 10.1016/j.expneurol.2019.112988] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 03/29/2019] [Accepted: 06/25/2019] [Indexed: 12/12/2022]
Abstract
The voltage-gated potassium (Kv) channel blockers tetraethylammonium (TEA) and 4-aminopyridine (4-AP) have shown beneficial effects on some neurological disorders. But their involvements in diabetes-associated cognitive dysfunction are still unknown. The present study aims to investigate whether the blockade of Kv channels by TEA and 4-AP alleviate cognitive decline in diabetes. In vivo, the effects of TEA and 4-AP (5 mg/kg body weight per day, 1 mg/kg body weight per day intraperitoneal injected for 4 weeks, respectively) were investigated in streptozotocin-induced C57BL/6 diabetic mice. In vitro study, we investigated the effects of TEA and 4-AP on the high glucose (HG) -stimulated primary cortical neurons. The results showed that TEA and 4-AP ameliorated the cognitive decline of diabetic mice in the Morris water maze test, improved the ultrastructure of pancreatic β cells, hippocampal neurons and synapses, decreased oxidative stress, modulated apoptosis-related proteins, and activated phosphatidylinositol 3-kinase (PI3K)/ Protein kinase-B (PKB or Akt) signaling pathway. In the HG-stimulated primary cultured cortical neurons, TEA and 4-AP increased the cell viability, decreased oxidative stress; prevented apoptosis and activated PI3K/Akt signaling pathway. Additionally, the PI3K inhibitor LY294002 partially abolished the effects of TEA and 4-AP. These findings indicate that the blockade of Kv channels by TEA and 4-AP ameliorates the diabetes-associated cognitive dysfunction via PI3K/Akt pathway, suggesting that targeting Kv channels could be a promising strategy for the treatments of cognitive impairments in diabetes.
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Affiliation(s)
- Wenhui Yan
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, Shaanxi, China
| | - Meng Zhang
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, Shaanxi, China
| | - Ye Yu
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, Shaanxi, China
| | - Xinyao Yi
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, Shaanxi, China
| | - Tingli Guo
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, Shaanxi, China
| | - Hao Hu
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, Shaanxi, China
| | - Qiang Sun
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, Shaanxi, China
| | - Mingxia Chen
- Electron Microscopy Room, Xi'an Jiaotong University Health Science Center, Xi'an 710061, Shaanxi, China
| | - Huangui Xiong
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5880, USA.
| | - Lina Chen
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, Shaanxi, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an 710061, Shaanxi, China.
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11
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Genistein Inhibits Aβ 25-35-Induced Neuronal Death with Changes in the Electrophysiological Properties of Voltage-Gated Sodium and Potassium Channels. Cell Mol Neurobiol 2019; 39:809-822. [PMID: 31037516 DOI: 10.1007/s10571-019-00680-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Accepted: 04/25/2019] [Indexed: 01/07/2023]
Abstract
We established a model of Alzheimer's disease in vitro by exposing primary hippocampal neurons of neonatal Wistar rats to the β-Amyloid peptide fragment 25-35, Aβ25-35. We then observed the effects of genistein, a type of soybean isoflavone, on Aβ25-35-incubated hippocampal neuron viability, and the electrophysiological properties of voltage-gated sodium channels (NaV) and potassium channels (KV) in the hippocampal neurons. Aβ25-35 exposure reduced the viability of hippocampal neurons, decreased the peak amplitude of voltage-activated sodium channel currents (INa), and significantly reduced INa at different membrane potentials. Moreover, Aβ25-35 shifted the activation curve toward depolarization, shifted the inactivation curve toward hyperpolarization, and increased the time constant of recovery from inactivation. Aβ25-35 exposure significantly shifted the inactivation curve of transient outward K+ currents (IA) toward hyperpolarization and increased its time constant of recovery from inactivation. In addition, Aβ25-35 significantly decreased the peak density of outward-delayed rectifier potassium channel currents (IDR) and significantly reduced IDR value at different membrane potentials. We found that genistein partially reversed the decrease in hippocampal neuron viability, and the alterations in electrophysiological properties of NaV and KV induced by Aβ25-35. Our results suggest that genistein could inhibit Aβ25-35-induced neuronal damage with changes in the electrophysiological properties of NaV and KV.
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Huang IY, Hsu YL, Chen CC, Chen MF, Wen ZH, Huang HT, Liu IY. Excavatolide-B Enhances Contextual Memory Retrieval via Repressing the Delayed Rectifier Potassium Current in the Hippocampus. Mar Drugs 2018; 16:md16110405. [PMID: 30366389 PMCID: PMC6266063 DOI: 10.3390/md16110405] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 10/21/2018] [Accepted: 10/22/2018] [Indexed: 12/18/2022] Open
Abstract
Memory retrieval dysfunction is a symptom of schizophrenia, autism spectrum disorder (ASD), and absence epilepsy (AE), as well as an early sign of Alzheimer’s disease. To date, few drugs have been reported to enhance memory retrieval. Here, we found that a coral-derived natural product, excavatolide-B (Exc-B), enhances contextual memory retrieval in both wild-type and Cav3.2−/− mice via repressing the delayed rectifier potassium current, thus lowering the threshold for action potential initiation and enhancing induction of long-term potentiation (LTP). The human CACNA1H gene encodes a T-type calcium channel (Cav3.2), and its mutation is associated with schizophrenia, ASD, and AE, which are all characterized by abnormal memory function. Our previous publication demonstrated that Cav3.2−/− mice exhibit impaired contextual-associated memory retrieval, whilst their retrieval of spatial memory and auditory cued memory remain intact. The effect of Exc-B on enhancing the retrieval of context-associated memory provides a hope for novel drug development.
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Affiliation(s)
- Irene Y Huang
- Department of Molecular Biology and Human Genetics, Tzu Chi University, Hualien 970, Taiwan.
| | - Yu-Luan Hsu
- Department of Molecular Biology and Human Genetics, Tzu Chi University, Hualien 970, Taiwan.
| | - Chien-Chang Chen
- Institute of Biomedical Sciences, Academia Sinica, 128, Academia road, Section 2, Nangang, Taipei 115, Taiwan.
| | - Mei-Fang Chen
- Cardiovascular and Metabolomics Research Center, Department of Medical Research, Buddhist Tzu Chi General Hospital, Hualien 970, Taiwan.
| | - Zhi-Hong Wen
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan.
| | - Hsien-Ting Huang
- Department of Molecular Biology and Human Genetics, Tzu Chi University, Hualien 970, Taiwan.
- Institute of Medical Sciences, Tzu Chi University, Hualien 970, Taiwan.
| | - Ingrid Y Liu
- Department of Molecular Biology and Human Genetics, Tzu Chi University, Hualien 970, Taiwan.
- Institute of Medical Sciences, Tzu Chi University, Hualien 970, Taiwan.
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13
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Paeonol promotes hippocampal synaptic transmission: The role of the Kv2.1 potassium channel. Eur J Pharmacol 2018; 827:227-237. [PMID: 29550337 DOI: 10.1016/j.ejphar.2018.03.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 03/09/2018] [Accepted: 03/14/2018] [Indexed: 12/30/2022]
Abstract
Paeonol is a major constituent of the Chinese herb Moutan cortex radices. Recent studies report that paeonol has neuroprotective effects and improves impaired learning and memory. However, its underlying mechanisms by which paeonol contributes to synaptic transmission remain unclear. In this study, we found that paeonol increased the frequency of miniature excitatory postsynaptic currents (mEPSCs) and spontaneous excitatory postsynaptic currents (sEPSCs), but had no effect on the amplitude in rat hippocampal CA1 neurons. Similarly, the acetylcholinesterase (AChE) inhibitor rivastigmine increased the frequency of mEPSCs, but had no effect upon amplitude in rat hippocampal neurons. Rivastigmine also inhibited the delayed outward K+ currents in rat hippocampal CA1 neurons, but had no effect in nucleus ambiguus (NA) neurons. The Kv2 blocker guangxitoxin-1E increased the frequency of both mEPSCs and sEPSCs of rat hippocampal CA1 neurons, without affecting their amplitude. Our results suggest that paeonol and rivastigmine enhance spontaneous presynaptic transmitter release, which may be associated with the inhibition of the hippocampal Kv2 current and with therapeutic potential in neurotransmitter deficits found in Alzheimer's disease (AD). Moreover, our data also show that paeonol protects against Aβ25-35-induced impairment of long-term potentiation (LTP) in mouse hippocampal neurons. However, guangxitoxin-1E failed to potentiate the evoked field excitatory postsynaptic potentials (fEPSPs), LTP and Aβ25-35-induced impairment of LTP. These results indicate that paeonol may has the potential to improve learning and memory in AD. Interestingly, this effect is not involved in the inhibition of the hippocampal Kv2 current.
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14
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May LM, Anggono V, Gooch HM, Jang SE, Matusica D, Kerbler GM, Meunier FA, Sah P, Coulson EJ. G-Protein-Coupled Inwardly Rectifying Potassium (GIRK) Channel Activation by the p75 Neurotrophin Receptor Is Required for Amyloid β Toxicity. Front Neurosci 2017; 11:455. [PMID: 28848381 PMCID: PMC5550722 DOI: 10.3389/fnins.2017.00455] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 07/26/2017] [Indexed: 02/05/2023] Open
Abstract
Alzheimer's disease is characterized by cognitive decline, neuronal degeneration, and the accumulation of amyloid-beta (Aβ). Although, the neurotoxic Aβ peptide is widely believed to trigger neuronal dysfunction and degeneration in Alzheimer's disease, the mechanism by which this occurs is poorly defined. Here we describe a novel, Aβ-triggered apoptotic pathway in which Aβ treatment leads to the upregulation of G-protein activated inwardly rectifying potassium (GIRK/Kir3) channels, causing potassium efflux from neurons and Aβ-mediated apoptosis. Although, GIRK channel activity is required for Aβ-induced neuronal degeneration, we show that it is not sufficient, with coincident signaling by the p75 neurotrophin receptor (p75NTR) also required for potassium efflux and cell death. Our results identify a novel role for GIRK channels in mediating apoptosis, and provide a previously missing mechanistic link between the excitotoxicity of Aβ and its ability to trigger cell death pathways, such as that mediated by p75NTR. We propose that this death-signaling pathway contributes to the dysfunction of neurons in Alzheimer's disease and is responsible for their eventual degeneration.
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Affiliation(s)
- Linda M May
- Queensland Brain Institute, University of QueenslandBrisbane, QLD, Australia
| | - Victor Anggono
- Queensland Brain Institute, University of QueenslandBrisbane, QLD, Australia.,Clem Jones Centre for Ageing Dementia Research, University of QueenslandBrisbane, QLD, Australia
| | - Helen M Gooch
- Queensland Brain Institute, University of QueenslandBrisbane, QLD, Australia
| | - Se E Jang
- Queensland Brain Institute, University of QueenslandBrisbane, QLD, Australia.,Clem Jones Centre for Ageing Dementia Research, University of QueenslandBrisbane, QLD, Australia
| | - Dusan Matusica
- Queensland Brain Institute, University of QueenslandBrisbane, QLD, Australia.,Centre for Neuroscience, College of Medicine and Public Health, Flinders UniversityAdelaide, SA, Australia
| | - Georg M Kerbler
- Queensland Brain Institute, University of QueenslandBrisbane, QLD, Australia
| | - Frederic A Meunier
- Queensland Brain Institute, University of QueenslandBrisbane, QLD, Australia.,Clem Jones Centre for Ageing Dementia Research, University of QueenslandBrisbane, QLD, Australia
| | - Pankaj Sah
- Queensland Brain Institute, University of QueenslandBrisbane, QLD, Australia
| | - Elizabeth J Coulson
- Queensland Brain Institute, University of QueenslandBrisbane, QLD, Australia.,Clem Jones Centre for Ageing Dementia Research, University of QueenslandBrisbane, QLD, Australia.,School of Biomedical Sciences, University of QueenslandBrisbane, QLD, Australia
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15
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16
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Roberts BR, Doecke JD, Rembach A, Yévenes LF, Fowler CJ, McLean CA, Lind M, Volitakis I, Masters CL, Bush AI, Hare DJ. Rubidium and potassium levels are altered in Alzheimer's disease brain and blood but not in cerebrospinal fluid. Acta Neuropathol Commun 2016; 4:119. [PMID: 27842602 PMCID: PMC5109650 DOI: 10.1186/s40478-016-0390-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 10/29/2016] [Indexed: 12/21/2022] Open
Abstract
Loss of intracellular compartmentalization of potassium is a biochemical feature of Alzheimer's disease indicating a loss of membrane integrity and mitochondrial dysfunction. We examined potassium and rubidium (a biological proxy for potassium) in brain tissue, blood fractions and cerebrospinal fluid from Alzheimer's disease and healthy control subjects to investigate the diagnostic potential of these two metal ions. We found that both potassium and rubidium levels were significantly decreased across all intracellular compartments in the Alzheimer's disease brain. Serum from over 1000 participants in the Australian Imaging, Biomarkers and Lifestyle Flagship Study of Ageing (AIBL), showed minor changes according to disease state. Potassium and rubidium levels in erythrocytes and cerebrospinal fluid were not significantly different according to disease state, and rubidium was slightly decreased in Alzheimer's disease patients compared to healthy controls. Our data provides evidence that contrasts the hypothesized disruption of the blood-brain barrier in Alzheimer's disease, with the systemic decrease in cortical potassium and rubidium levels suggesting influx of ions from the blood is minimal and that the observed changes are more likely indicative of an internal energy crisis within the brain. These findings may be the basis for potential diagnostic imaging studies using radioactive potassium and rubidium tracers.
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Wu KW, Kou ZW, Mo JL, Deng XX, Sun FY. Neurovascular coupling protects neurons against hypoxic injury via inhibition of potassium currents by generation of nitric oxide in direct neuron and endothelium cocultures. Neuroscience 2016; 334:275-282. [PMID: 27531855 DOI: 10.1016/j.neuroscience.2016.08.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/15/2016] [Accepted: 08/07/2016] [Indexed: 12/15/2022]
Abstract
This study examined the effect of neuron-endothelial coupling on the survival of neurons after ischemia and the possible mechanism underlying that effect. Whole-cell patch-clamp experiments were performed on cortical neurons cultured alone or directly cocultured with brain microvascular endothelial cells (BMEC). Propidium iodide (PI) and NeuN staining were performed to examine neuronal death following oxygen and glucose deprivation (OGD). We found that the neuronal transient outward potassium currents (IA) decreased in the coculture system, whereas the outward delayed-rectifier potassium currents (IK) did not. Sodium nitroprusside, a NO donor, enhanced BMEC-induced IA inhibition and nitro-l-arginine methylester, a NOS inhibitor, partially prevented this inhibition. Moreover, the neurons directly cocultured with BMEC showed more resistance to OGD-induced injury compared with the neurons cultured alone, and that neuroprotective effect was abolished by treatment with NS5806, an activator of the IA. These results indicate that vascular endothelial cells assist neurons to prevent hypoxic injury via inhibiting neuronal IA by production of NO in the direct neuron-BMEC coculture system. These results further provide direct evidence of functional coupling between neurons and vascular endothelial cells. This study clearly demonstrates that vascular endothelial cells play beneficial roles in the pathophysiological processes of neurons after hypoxic injury, suggesting that the improvement of neurovascular coupling or functional remodeling may become an important therapeutic target for preventing brain injury.
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Affiliation(s)
- Kun-Wei Wu
- Institute of Biomedical Sciences and Department of Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, PR China; Shanghai Key Laboratory of Clinical Geriatric Medicine, Research Center on Aging and Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, PR China
| | - Zeng-Wei Kou
- Shanghai Key Laboratory of Clinical Geriatric Medicine, Research Center on Aging and Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, PR China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, PR China
| | - Jia-Lin Mo
- Shanghai Key Laboratory of Clinical Geriatric Medicine, Research Center on Aging and Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, PR China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, PR China
| | - Xu-Xu Deng
- Shanghai Key Laboratory of Clinical Geriatric Medicine, Research Center on Aging and Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, PR China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, PR China
| | - Feng-Yan Sun
- Institute of Biomedical Sciences and Department of Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, PR China; Shanghai Key Laboratory of Clinical Geriatric Medicine, Research Center on Aging and Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, PR China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, PR China.
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18
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Ramasamy VS, Islam MI, Haque MA, Shin SY, Park IS. β-Amyloid induces nuclear protease-mediated lamin fragmentation independent of caspase activation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1189-99. [PMID: 26876308 DOI: 10.1016/j.bbamcr.2016.02.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 01/18/2016] [Accepted: 02/09/2016] [Indexed: 01/22/2023]
Abstract
β-Amyloid (Aβ), a hallmark peptide of Alzheimer's disease, induces both caspase-dependent apoptosis and non-apoptotic cell death. In this study, we examined caspase-independent non-apoptotic cell death preceding caspase activation in Aβ42-treated cells. We first determined the optimal treatment conditions for inducing cell death without caspase activation and selected a double-treatment method involving the incubation of cells with Aβ42 for 4 and 6 h (4+6 h sample). We observed that levels of lamin A (LA) and lamin B (LB) were reduced in the 4+6 h samples. This reduction was decreased by treatment with suc-AAPF-CMK, an inhibitor of nuclear scaffold (NS) protease, but not by treatment with z-VAD-FMK, a pan-caspase inhibitor. In addition, suc-AAPF-CMK decreased the changes in nuclear morphology observed in cells in the 4+6 h samples, which were different from nuclear fragmentation observed in STS-treated cells. Furthermore, suc-AAPF-CMK inhibited cell death in the 4+6 h samples. LA and LB fragmentation occurred in the isolated nuclei and was also inhibited by suc-AAPF-CMK. Together, these data indicated that the fragmentation of LA and LB in the Aβ42-treated cells was induced by an NS protease, whose identity is not clearly determined yet. A correlation between Aβ42 toxicity and the lamin fragmentation by NS protease suggests that inhibition of the protease could be an effective method for controlling the pathological process of AD.
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Affiliation(s)
- Vijay Sankar Ramasamy
- Department of Bio-Materials Engineering, Chosun University, Gwangju 501-759, Republic of Korea
| | - Md Imamul Islam
- Department of Bio-Materials Engineering, Chosun University, Gwangju 501-759, Republic of Korea
| | - Md Aminul Haque
- Department of Bio-Materials Engineering, Chosun University, Gwangju 501-759, Republic of Korea
| | - Song Yub Shin
- Department of Bio-Materials Engineering, Chosun University, Gwangju 501-759, Republic of Korea; Cellular and Molecular Medicine, Chosun University, Gwangju 501-759, Republic of Korea
| | - Il-Seon Park
- Department of Bio-Materials Engineering, Chosun University, Gwangju 501-759, Republic of Korea; Cellular and Molecular Medicine, Chosun University, Gwangju 501-759, Republic of Korea.
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19
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VEGF attenuated increase of outward delayed-rectifier potassium currents in hippocampal neurons induced by focal ischemia via PI3-K pathway. Neuroscience 2015; 298:94-101. [DOI: 10.1016/j.neuroscience.2015.04.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 04/03/2015] [Accepted: 04/07/2015] [Indexed: 12/14/2022]
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20
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Wang F, Zhang Y, Wang L, Sun P, Luo X, Ishigaki Y, Sugai T, Yamamoto R, Kato N. Improvement of spatial learning by facilitating large-conductance calcium-activated potassium channel with transcranial magnetic stimulation in Alzheimer's disease model mice. Neuropharmacology 2015; 97:210-9. [PMID: 26051398 DOI: 10.1016/j.neuropharm.2015.05.027] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 05/04/2015] [Accepted: 05/26/2015] [Indexed: 01/13/2023]
Abstract
Transcranial magnetic stimulation (TMS) is fragmentarily reported to be beneficial to Alzheimer's patients. Its underlying mechanism was investigated. TMS was applied at 1, 10 or 15 Hz daily for 4 weeks to young Alzheimer's disease model mice (3xTg), in which intracellular soluble amyloid-β is notably accumulated. Hippocampal long-term potentiation (LTP) was tested after behavior. TMS ameliorated spatial learning deficits and enhanced LTP in the same frequency-dependent manner. Activity of the large conductance calcium-activated potassium (Big-K; BK) channels was suppressed in 3xTg mice and recovered by TMS frequency-dependently. These suppression and recovery were accompanied by increase and decrease in cortical excitability, respectively. TMS frequency-dependently enhanced the expression of the activity-dependently expressed scaffold protein Homer1a, which turned out to enhance BK channel activity. Isopimaric acid, an activator of the BK channel, magnified LTP. Amyloid-β lowering was detected after TMS in 3xTg mice. In 3xTg mice with Homer1a knocked out, amyloid-β lowering was not detected, though the TMS effects on BK channel and LTP remained. We concluded that TMS facilitates BK channels both Homer1a-dependently and -independently, thereby enhancing hippocampal LTP and decreasing cortical excitability. Reduced excitability contributed to amyloid-β lowering. A cascade of these correlated processes, triggered by TMS, was likely to improve learning in 3xTg mice.
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Affiliation(s)
- Furong Wang
- Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan; Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yu Zhang
- Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan; Medical College, Qinghai University, Xinin 810016, China
| | - Li Wang
- Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan; China-Japan Friendship Hospital, Beijing 100029, China
| | - Peng Sun
- Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan; Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xianwen Luo
- Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan; Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yasuhito Ishigaki
- Medical Research Institute, Kanazawa Medical University, Ishikawa 920-0293, Japan
| | - Tokio Sugai
- Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan
| | - Ryo Yamamoto
- Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan
| | - Nobuo Kato
- Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan.
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Brain mitochondrial ATP-insensitive large conductance Ca⁺²-activated K⁺ channel properties are altered in a rat model of amyloid-β neurotoxicity. Exp Neurol 2015; 269:8-16. [PMID: 25828534 DOI: 10.1016/j.expneurol.2014.12.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 12/01/2014] [Accepted: 12/20/2014] [Indexed: 12/22/2022]
Abstract
Mitochondrial dysfunction is a hallmark of amyloid-beta (Aβ)-induced neuronal toxicity in Alzheimer's disease (AD). However, the underlying mechanism of how Aβ affects mitochondrial function remains uncertain. Because mitochondrial potassium channels have been involved in several mitochondrial functions including cytoprotection, apoptosis and calcium homeostasis, a study was undertaken to investigate whether the gating behavior of the mitochondrial ATP- and ChTx-insensitive-IbTx-sensitive Ca(2+)-activated potassium channel (mitoBKCa) is altered in a rat model of Aβ neurotoxicity. Aβ1-42 (4 μg/μl) was intracerebroventricularly injected in male Wistar rats (220-250 g). Brain Aβ accumulation was confirmed two weeks later on the basis of an immunohistochemistry staining assay, and physiological impacts measured in passive avoidance task cognitive performance experiments. Brain mitochondrial inner membranes were then extracted and membrane vesicles prepared for channel incorporation into bilayer lipid. Purity of the cell fraction was confirmed by Western blot using specific markers of mitochondria, plasma membrane, endoplasmic reticulum, and Golgi. Our results first provide evidence for differences in mitoBKCa ion permeation properties with channels coming from Aβ vesicle preparations characterized by an inward rectifying I-V curve, in contrast to control mitoBKCa channels which showed a linear I-V relationship under the same ionic conditions (200 mM cis/50mM trans). More importantly the open probability of channels from Aβ vesicles appeared 1.5 to 2.5 smaller compared to controls, the most significant decrease being observed at depolarizing potentials (30 mV to 50 mV). Because BKCa-β4 subunit has been documented to shift the BKCa channel voltage dependence curve, a Western blot analysis was undertaken where expression of mitoBKCa α and β4 subunits was estimated using anti-α and β4 subunit antibodies. Our results indicated a significant increase in mitoBKCa-β4 subunit expression coupled to a decrease in the expression of α subunit. Our results thus demonstrate a modification in the mitoBKCa channel gating properties in membrane preparations coming from a rat model of Aβ neurotoxicity, an effect potentially linked to a change in mitoBKCa-β4 and -α subunits expression or increased ROS production due to an enhanced Aβ mitochondrial accumulation. Our results may provide new insights into the cellular mechanisms underlying mitochondrial dysfunctions in Aβ neurotoxicity.
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22
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Ping Y, Hahm ET, Waro G, Song Q, Vo-Ba DA, Licursi A, Bao H, Ganoe L, Finch K, Tsunoda S. Linking aβ42-induced hyperexcitability to neurodegeneration, learning and motor deficits, and a shorter lifespan in an Alzheimer's model. PLoS Genet 2015; 11:e1005025. [PMID: 25774758 PMCID: PMC4361604 DOI: 10.1371/journal.pgen.1005025] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 01/25/2015] [Indexed: 11/19/2022] Open
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia in the elderly. β-amyloid (Aβ) accumulation in the brain is thought to be a primary event leading to eventual cognitive and motor dysfunction in AD. Aβ has been shown to promote neuronal hyperactivity, which is consistent with enhanced seizure activity in mouse models and AD patients. Little, however, is known about whether, and how, increased excitability contributes to downstream pathologies of AD. Here, we show that overexpression of human Aβ42 in a Drosophila model indeed induces increased neuronal activity. We found that the underlying mechanism involves the selective degradation of the A-type K+ channel, Kv4. An age-dependent loss of Kv4 leads to an increased probability of AP firing. Interestingly, we find that loss of Kv4 alone results in learning and locomotion defects, as well as a shortened lifespan. To test whether the Aβ42-induced increase in neuronal excitability contributes to, or exacerbates, downstream pathologies, we transgenically over-expressed Kv4 to near wild-type levels in Aβ42-expressing animals. We show that restoration of Kv4 attenuated age-dependent learning and locomotor deficits, slowed the onset of neurodegeneration, and partially rescued premature death seen in Aβ42-expressing animals. We conclude that Aβ42-induced hyperactivity plays a critical role in the age-dependent cognitive and motor decline of this Aβ42-Drosophila model, and possibly in AD.
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Affiliation(s)
- Yong Ping
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Eu-Teum Hahm
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Girma Waro
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Qian Song
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Dai-An Vo-Ba
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Ashley Licursi
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Han Bao
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Logan Ganoe
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Kelly Finch
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Susan Tsunoda
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail:
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23
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Peers C, Boyle JP. Oxidative modulation of K+ channels in the central nervous system in neurodegenerative diseases and aging. Antioxid Redox Signal 2015; 22:505-21. [PMID: 25333910 DOI: 10.1089/ars.2014.6007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
SIGNIFICANCE Oxidative stress and damage are well-established components of neurodegenerative diseases, contributing to neuronal death during disease progression. Here, we consider key K(+) channels as target proteins that can undergo oxidative modulation, describe what is understood about how this influences disease progression, and consider regulation of these channels by gasotransmitters as a means of cellular protection. RECENT ADVANCES Oxidative regulation of the delayed rectifier Kv2.1 and the Ca(2+)- and voltage-sensitive BK channel are established, but recent studies contest how their redox sensitivity contributes to altered excitability, progression of neurodegenerative diseases, and healthy aging. CRITICAL ISSUES Both Kv2.1 and BK channels have recently been established as target proteins for regulation by the gasotransmitters carbon monoxide and hydrogen sulfide. Establishing the molecular basis of such regulation, and exactly how this influences excitability and vulnerability to apoptotic cell death will determine whether such regulation can be exploited for therapeutic benefit. FUTURE DIRECTIONS Developing a more comprehensive picture of the oxidative modulation of K(+) channels (and, indeed, other ion channels) within the central nervous system in health and disease will enable us to better understand processes associated with healthy aging as well as distinct processes underlying progression of neurodegenerative diseases. Advances in the growing understanding of how gasotransmitters can regulate ion channels, including redox-sensitive K(+) channels, are a research priority for this field, and will establish their usefulness in design of future approaches for the treatment of such diseases.
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Affiliation(s)
- Chris Peers
- Division of Cardiovascular and Diabetes Research, Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), Faculty of Medicine and Health, University of Leeds , Leeds, United Kingdom
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Dopamine D1 and D5 receptors modulate spike timing-dependent plasticity at medial perforant path to dentate granule cell synapses. J Neurosci 2015; 34:15888-97. [PMID: 25429131 DOI: 10.1523/jneurosci.2400-14.2014] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although evidence suggests that DA modulates hippocampal function, the mechanisms underlying that dopaminergic modulation are largely unknown. Using perforated-patch electrophysiological techniques to maintain the intracellular milieu, we investigated how the activation of D1-type DA receptors regulates spike timing-dependent plasticity (STDP) of the medial perforant path (mPP) synapse onto dentate granule cells. When D1-type receptors were inhibited, a relatively mild STDP protocol induced LTP only within a very narrow timing window between presynaptic stimulation and postsynaptic response. The stimulus protocol produced timing-dependent LTP (tLTP) only when the presynaptic stimulation was followed 30 ms later by depolarization-induced postsynaptic action potentials. That is, the time between presynaptic stimulation and postsynaptic response was 30 ms (Δt = +30 ms). When D1-type receptors were activated, however, the same mild STDP protocol induced tLTP over a much broader timing window: tLTP was induced when -30 ms ≤ Δt ≤ +30 ms. The result indicated that D1-type receptor activation enabled synaptic potentiation even when postsynaptic activity preceded presynaptic stimulation within this Δt range. Results with null mice lacking the Kv4.2 potassium channel and with the potassium channel inhibitor, 4-aminopyridine, suggested that D1-type receptors enhanced tLTP induction by suppressing the transient IA-type K(+) current. Results obtained with antagonists and DA receptor knock-out mice indicated that endogenous activity of both D1 and D5 receptors modulated plasticity in the mPP. The DA D5 receptors appeared particularly important in regulating plasticity of the mPP onto the dentate granule cells.
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Heme oxygenase-1 protects against Alzheimer's amyloid-β(1-42)-induced toxicity via carbon monoxide production. Cell Death Dis 2014; 5:e1569. [PMID: 25501830 PMCID: PMC4454163 DOI: 10.1038/cddis.2014.529] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 11/04/2014] [Accepted: 11/04/2014] [Indexed: 12/16/2022]
Abstract
Heme oxygenase-1 (HO-1), an inducible enzyme up-regulated in Alzheimer's disease, catabolises heme to biliverdin, Fe2+ and carbon monoxide (CO). CO can protect neurones from oxidative stress-induced apoptosis by inhibiting Kv2.1 channels, which mediates cellular K+ efflux as an early step in the apoptotic cascade. Since apoptosis contributes to the neuronal loss associated with amyloid β peptide (Aβ) toxicity in AD, we investigated the protective effects of HO-1 and CO against Aβ1-42 toxicity in SH-SY5Y cells, employing cells stably transfected with empty vector or expressing the cellular prion protein, PrPc, and rat primary hippocampal neurons. Aβ1-42 (containing protofibrils) caused a concentration-dependent decrease in cell viability, attributable at least in part to induction of apoptosis, with the PrPc-expressing cells showing greater susceptibility to Aβ1-42 toxicity. Pharmacological induction or genetic over-expression of HO-1 significantly ameliorated the effects of Aβ1-42. The CO-donor CORM-2 protected cells against Aβ1-42 toxicity in a concentration-dependent manner. Electrophysiological studies revealed no differences in the outward current pre- and post-Aβ1-42 treatment suggesting that K+ channel activity is unaffected in these cells. Instead, Aβ toxicity was reduced by the L-type Ca2+ channel blocker nifedipine, and by the CaMKKII inhibitor, STO-609. Aβ also activated the downstream kinase, AMP-dependent protein kinase (AMPK). CO prevented this activation of AMPK. Our findings indicate that HO-1 protects against Aβ toxicity via production of CO. Protection does not arise from inhibition of apoptosis-associated K+ efflux, but rather by inhibition of AMPK activation, which has been recently implicated in the toxic effects of Aβ. These data provide a novel, beneficial effect of CO which adds to its growing potential as a therapeutic agent.
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Notoginsenoside R1 increases neuronal excitability and ameliorates synaptic and memory dysfunction following amyloid elevation. Sci Rep 2014; 4:6352. [PMID: 25213453 PMCID: PMC4161968 DOI: 10.1038/srep06352] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 08/26/2014] [Indexed: 11/17/2022] Open
Abstract
Neurodegeneration and synaptic dysfunction observed in Alzheimer's disease (AD) have been associated with progressive decrease in neuronal activity. Here, we investigated the effects of Notoginsenoside R1 (NTR1), a major saponin isolated from Panax notoginseng, on neuronal excitability and assessed the beneficial effects of NTR1 on synaptic and memory deficits under the Aβ-enriched conditions in vivo and in vitro. We assessed the effects of NTR1 on neuronal excitability, membrane ion channel activity, and synaptic plasticity in acute hippocampal slices by combining electrophysiological extracellular and intracellular recording techniques. We found that NTR1 increased the membrane excitability of CA1 pyramidal neurons in hippocampal slices by lowering the spike threshold possibly through a mechanism involving in the inhibition of voltage-gated K+ currents. In addition, NTR1 reversed Aβ1-42 oligomers-induced impairments in long term potentiation (LTP). Reducing spontaneous firing activity with 10 nM tetrodotoxin (TTX) abolished the protective effect of NTR1 against Aβ-induced LTP impairment. Finally, oral administration of NTR1 improved the learning performance of the APP/PS1 mouse model of AD. Our work reveals a novel mechanism involving in modulation of cell strength, which contributes to the protective effects of NTR1 against Aβ neurotoxicity.
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Tan MS, Tan L, Jiang T, Zhu XC, Wang HF, Jia CD, Yu JT. Amyloid-β induces NLRP1-dependent neuronal pyroptosis in models of Alzheimer's disease. Cell Death Dis 2014; 5:e1382. [PMID: 25144717 PMCID: PMC4454321 DOI: 10.1038/cddis.2014.348] [Citation(s) in RCA: 219] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 07/10/2014] [Accepted: 07/21/2014] [Indexed: 12/24/2022]
Abstract
Increasing evidence has shown the aberrant expression of inflammasome-related proteins in Alzheimer's disease (AD) brain; these proteins, including NLRP1 inflammasome, are implicated in the execution of inflammatory response and pyroptotic death. Although current data are associated NLRP1 genetic variants with AD, the involvement of NLRP1 inflammasome in AD pathogenesis is still unknown. Using APPswe/PS1dE9 transgenic mice, we found that cerebral NLRP1 levels were upregulated. Our in vitro studies further showed that increased NLRP1-mediated caspase-1-dependent ‘pyroptosis' in cultured cortical neurons in response to amyloid-β. Moreover, we employed direct in vivo infusion of non-viral small-interfering RNA to knockdown NLRP1 or caspase-1 in APPswe/PS1dE9 brain, and discovered that these NLRP1 or caspase-1 deficiency mice resulted in significantly reduced neuronal pyroptosis and reversed cognitive impairments. Taken together, our findings indicate an important role for NLRP1/caspase-1 signaling in AD progression, and point to the modulation of NLRP1 inflammasome as a promising strategy for AD therapy.
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Affiliation(s)
- M-S Tan
- Department of Neurology, Qingdao Municipal Hospital, College of Medicine and Pharmaceutics, Ocean University of China, Qingdao, China
| | - L Tan
- 1] Department of Neurology, Qingdao Municipal Hospital, College of Medicine and Pharmaceutics, Ocean University of China, Qingdao, China [2] Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China [3] Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao, China
| | - T Jiang
- Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao, China
| | - X-C Zhu
- Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao, China
| | - H-F Wang
- Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao, China
| | - C-D Jia
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - J-T Yu
- 1] Department of Neurology, Qingdao Municipal Hospital, College of Medicine and Pharmaceutics, Ocean University of China, Qingdao, China [2] Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China [3] Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao, China [4] Department of Neurology, Memory and Aging Center, University of California, San Francisco, CA, USA
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Effects of SKF83959 on the excitability of hippocampal CA1 pyramidal neurons: a modeling study. Acta Pharmacol Sin 2014; 35:738-51. [PMID: 24858313 DOI: 10.1038/aps.2014.23] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 03/03/2014] [Indexed: 12/31/2022] Open
Abstract
AIM 3-Methyl-6-chloro-7,8-hydroxy-1-(3-methylphenyl)-2,3,4,5-tetrahydro-1H-3-benzazepine (SKF83959) have been shown to affect several types of voltage-dependent channels in hippocampal pyramidal neurons. The aim of this study was to determine how modulation of a individual type of the channels by SKF83959 contributes to the overall excitability of CA1 pyramidal neurons during either direct current injections or synaptic activation. METHODS Rat hippocampal slices were prepared. The kinetics of voltage-dependent Na(+) channels and neuronal excitability and depolarization block in CA1 pyramidal neurons were examined using whole-cell recording. A realistic mathematical model of hippocampal CA1 pyramidal neuron was used to simulate the effects of SKF83959 on neuronal excitability. RESULTS SKF83959 (50 μmol/L) shifted the inactivation curve of Na(+) current by 10.3 mV but had no effect on the activation curve in CA1 pyramidal neurons. The effects of SKF83959 on passive membrane properties, including a decreased input resistance and depolarized resting potential, predicted by our simulations were in agreement with the experimental data. The simulations showed that decreased excitability of the soma by SKF83959 (examined with current injection at the soma) was only observed when the membrane potential was compensated to the control levels, whereas the decreased dendritic excitability (examined with current injection at the dendrite) was found even without membrane potential compensation, which led to a decreased number of action potentials initiated at the soma. Moreover, SKF83959 significantly facilitated depolarization block in CA1 pyramidal neurons. SKF83959 decreased EPSP temporal summation and, of physiologically greater relevance, the synaptic-driven firing frequency. CONCLUSION SKF83959 decreased the excitability of CA1 pyramidal neurons even though the drug caused the membrane potential depolarization. The results may reveal a partial mechanism for the drug's anti-Parkinsonian effects and may also suggest that SKF83959 has a potential antiepileptic effect.
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Yang X, Yang Q, Wang X, Luo C, Wan Y, Li J, Liu K, Zhou M, Zhang C. MicroRNA expression profile and functional analysis reveal that miR-206 is a critical novel gene for the expression of BDNF induced by ketamine. Neuromolecular Med 2014. [PMID: 24839168 DOI: 10.1007/12017-014-8312-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Depression is a major social and health concern, and ketamine exerts a quick, remarkable and persistent anti-depressive effect. microRNAs (miRNAs) show remarkable potential in the treatment of clinical depression. Here, we determined the expression profile of miRNAs in the hippocampus of rats treated with ketamine (15 mg/kg). The results suggest that multiple miRNAs were aberrantly expressed in rat hippocampus after ketamine injection (18 miRNAs were significantly reduced, while 22 miRNAs were significantly increased). Among them, miR-206 was down-regulated in ketamine-treated rats. In both cultured neuronal cells in vitro and hippocampus in vivo, we identified that the brain-derived neurotrophic factor (BDNF) was a direct target gene of miR-206. Via this target gene, miR-206 strongly modulated the expression of BDNF. Moreover, overexpression of miR-206 significantly attenuated ketamine-induced up-regulation of BDNF. The results indicated that miRNA-206 was involved in novel therapeutic targets for the anti-depressive effect of ketamine.
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Affiliation(s)
- Xiaolin Yang
- Department of Anesthesiology, Affiliated Hospital of Luzhou Medical College, Luzhou, 646000, Sichuan Province, China
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Yang X, Yang Q, Wang X, Luo C, Wan Y, Li J, Liu K, Zhou M, Zhang C. MicroRNA expression profile and functional analysis reveal that miR-206 is a critical novel gene for the expression of BDNF induced by ketamine. Neuromolecular Med 2014; 16:594-605. [PMID: 24839168 DOI: 10.1007/s12017-014-8312-z] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 05/06/2014] [Indexed: 01/12/2023]
Abstract
Depression is a major social and health concern, and ketamine exerts a quick, remarkable and persistent anti-depressive effect. microRNAs (miRNAs) show remarkable potential in the treatment of clinical depression. Here, we determined the expression profile of miRNAs in the hippocampus of rats treated with ketamine (15 mg/kg). The results suggest that multiple miRNAs were aberrantly expressed in rat hippocampus after ketamine injection (18 miRNAs were significantly reduced, while 22 miRNAs were significantly increased). Among them, miR-206 was down-regulated in ketamine-treated rats. In both cultured neuronal cells in vitro and hippocampus in vivo, we identified that the brain-derived neurotrophic factor (BDNF) was a direct target gene of miR-206. Via this target gene, miR-206 strongly modulated the expression of BDNF. Moreover, overexpression of miR-206 significantly attenuated ketamine-induced up-regulation of BDNF. The results indicated that miRNA-206 was involved in novel therapeutic targets for the anti-depressive effect of ketamine.
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Affiliation(s)
- Xiaolin Yang
- Department of Anesthesiology, Affiliated Hospital of Luzhou Medical College, Luzhou, 646000, Sichuan Province, China
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McCord MC, Aizenman E. The role of intracellular zinc release in aging, oxidative stress, and Alzheimer's disease. Front Aging Neurosci 2014; 6:77. [PMID: 24860495 PMCID: PMC4028997 DOI: 10.3389/fnagi.2014.00077] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 04/02/2014] [Indexed: 01/26/2023] Open
Abstract
Brain aging is marked by structural, chemical, and genetic changes leading to cognitive decline and impaired neural functioning. Further, aging itself is also a risk factor for a number of neurodegenerative disorders, most notably Alzheimer’s disease (AD). Many of the pathological changes associated with aging and aging-related disorders have been attributed in part to increased and unregulated production of reactive oxygen species (ROS) in the brain. ROS are produced as a physiological byproduct of various cellular processes, and are normally detoxified by enzymes and antioxidants to help maintain neuronal homeostasis. However, cellular injury can cause excessive ROS production, triggering a state of oxidative stress that can lead to neuronal cell death. ROS and intracellular zinc are intimately related, as ROS production can lead to oxidation of proteins that normally bind the metal, thereby causing the liberation of zinc in cytoplasmic compartments. Similarly, not only can zinc impair mitochondrial function, leading to excess ROS production, but it can also activate a variety of extra-mitochondrial ROS-generating signaling cascades. As such, numerous accounts of oxidative neuronal injury by ROS-producing sources appear to also require zinc. We suggest that zinc deregulation is a common, perhaps ubiquitous component of injurious oxidative processes in neurons. This review summarizes current findings on zinc dyshomeostasis-driven signaling cascades in oxidative stress and age-related neurodegeneration, with a focus on AD, in order to highlight the critical role of the intracellular liberation of the metal during oxidative neuronal injury.
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Affiliation(s)
- Meghan C McCord
- Department of Neurobiology, University of Pittsburgh School of Medicine Pittsburgh, PA, USA
| | - Elias Aizenman
- Department of Neurobiology, University of Pittsburgh School of Medicine Pittsburgh, PA, USA
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Oligomeric amyloid β induces IL-1β processing via production of ROS: implication in Alzheimer's disease. Cell Death Dis 2013; 4:e975. [PMID: 24357806 PMCID: PMC3877570 DOI: 10.1038/cddis.2013.503] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 10/29/2013] [Accepted: 11/12/2013] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD) is a chronic neurodegenerative disease characterized by progressive neuronal loss and cognitive decline. Oligomeric amyloid β (oAβ) is involved in the pathogenesis of AD by affecting synaptic plasticity and inhibiting long-term potentiation. Although several lines of evidence suggests that microglia, the resident immune cells in the central nervous system (CNS), are neurotoxic in the development of AD, the mechanism whether or how oAβ induces microglial neurotoxicity remains unknown. Here, we show that oAβ promotes the processing of pro-interleukin (IL)-1β into mature IL-1β in microglia, which then enhances microglial neurotoxicity. The processing is induced by an increase in activity of caspase-1 and NOD-like receptor family, pyrin domain containing 3 (NLRP3) via mitochondrial reactive oxygen species (ROS) and partially via NADPH oxidase-induced ROS. The caspase-1 inhibitor Z-YVAD-FMK inhibits the processing of IL-1β, and attenuates microglial neurotoxicity. Our results indicate that microglia can be activated by oAβ to induce neuroinflammation through processing of IL-1β, a pro-inflammatory cytokine, in AD.
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Neuroinflammation and copper in Alzheimer's disease. Int J Alzheimers Dis 2013; 2013:145345. [PMID: 24369524 PMCID: PMC3863554 DOI: 10.1155/2013/145345] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 10/22/2013] [Indexed: 02/06/2023] Open
Abstract
Inflammation is the innate immune response to infection or tissue damage. Initiation of proinflammatory cascades in the central nervous system (CNS) occurs through recognition of danger associated molecular patterns by cognate immune receptors expressed on inflammatory cells and leads to rapid responses to remove the danger stimulus. The presence of activated microglia and astrocytes in the vicinity of amyloid plaques in the brains of Alzheimer's disease (AD) patients and mouse models implicates inflammation as a contributor to AD pathogenesis. Activated microglia play a critical role in amyloid clearance, but chronic deregulation of CNS inflammatory pathways results in secretion of neurotoxic mediators that ultimately contribute to neurodegeneration in AD. Copper (Cu) homeostasis is profoundly affected in AD, and accumulated extracellular Cu drives Aβ aggregation, while intracellular Cu deficiency limits bioavailable Cu required for CNS functions. This review presents an overview of inflammatory events that occur in AD in response to Aβ and highlights recent advances on the role of Cu in modulation of beneficial and detrimental inflammatory responses in AD.
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Shah NH, Aizenman E. Voltage-gated potassium channels at the crossroads of neuronal function, ischemic tolerance, and neurodegeneration. Transl Stroke Res 2013; 5:38-58. [PMID: 24323720 DOI: 10.1007/s12975-013-0297-7] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/14/2013] [Accepted: 10/14/2013] [Indexed: 11/29/2022]
Abstract
Voltage-gated potassium (Kv) channels are widely expressed in the central and peripheral nervous system and are crucial mediators of neuronal excitability. Importantly, these channels also actively participate in cellular and molecular signaling pathways that regulate the life and death of neurons. Injury-mediated increased K(+) efflux through Kv2.1 channels promotes neuronal apoptosis, contributing to widespread neuronal loss in neurodegenerative disorders such as Alzheimer's disease and stroke. In contrast, some forms of neuronal activity can dramatically alter Kv2.1 channel phosphorylation levels and influence their localization. These changes are normally accompanied by modifications in channel voltage dependence, which may be neuroprotective within the context of ischemic injury. Kv1 and Kv7 channel dysfunction leads to neuronal hyperexcitability that critically contributes to the pathophysiology of human clinical disorders such as episodic ataxia and epilepsy. This review summarizes the neurotoxic, neuroprotective, and neuroregulatory roles of Kv channels and highlights the consequences of Kv channel dysfunction on neuronal physiology. The studies described in this review thus underscore the importance of normal Kv channel function in neurons and emphasize the therapeutic potential of targeting Kv channels in the treatment of a wide range of neurological diseases.
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Affiliation(s)
- Niyathi Hegde Shah
- Department of Neurobiology, University of Pittsburgh School of Medicine, 3500 Terrace Street, E1456 BST, Pittsburgh, PA, 15261, USA,
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α-helical structures drive early stages of self-assembly of amyloidogenic amyloid polypeptide aggregate formation in membranes. Sci Rep 2013; 3:2781. [PMID: 24071712 PMCID: PMC3784961 DOI: 10.1038/srep02781] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 09/03/2013] [Indexed: 12/17/2022] Open
Abstract
The human islet amyloid polypeptide (hIAPP) is the primary component in the toxic islet amyloid deposits in type-2 diabetes. hIAPP self-assembles to aggregates that permeabilize membranes and constitutes amyloid plaques. Uncovering the mechanisms of amyloid self-assembly is the key to understanding amyloid toxicity and treatment. Although structurally similar, hIAPP's rat counterpart, the rat islet amyloid polypeptide (rIAPP), is non-toxic. It has been a puzzle why these peptides behave so differently. We combined multiscale modelling and theory to explain the drastically different dynamics of hIAPP and rIAPP: The differences stem from electrostatic dipolar interactions. hIAPP forms pentameric aggregates with the hydrophobic residues facing the membrane core and stabilizing water-conducting pores. We give predictions for pore sizes, the number of hIAPP peptides, and aggregate morphology. We show the importance of curvature-induced stress at the early stages of hIAPP assembly and the α-helical structures over β-sheets. This agrees with recent fluorescence spectroscopy experiments.
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36
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Guo L, Xing Y, Pan R, Jiang M, Gong Z, Lin L, Wang J, Xiong G, Dong J. Curcumin protects microglia and primary rat cortical neurons against HIV-1 gp120-mediated inflammation and apoptosis. PLoS One 2013; 8:e70565. [PMID: 23936448 PMCID: PMC3735595 DOI: 10.1371/journal.pone.0070565] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 06/24/2013] [Indexed: 12/18/2022] Open
Abstract
Curcumin is a molecule found in turmeric root that has anti-inflammatory, antioxidant, and anti-tumor properties and has been widely used as both an herbal drug and a food additive to treat or prevent neurodegenerative diseases. To explore whether curcumin is able to ameliorate HIV-1-associated neurotoxicity, we treated a murine microglial cell line (N9) and primary rat cortical neurons with curcumin in the presence or absence of neurotoxic HIV-1 gp120 (V3 loop) protein. We found that HIV-1 gp120 profoundly induced N9 cells to produce reactive oxygen species (ROS), tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1). HIV-1 gp120 also induced apoptosis of primary rat cortical neurons. Curcumin exerted a powerful inhibitory effect against HIV-1 gp120-induced neuronal damage, reducing the production of ROS, TNF-α and MCP-1 by N9 cells and inhibiting apoptosis of primary rat cortical neurons. Curcumin may exert its biological activities through inhibition of the delayed rectification and transient outward potassium (K(+)) current, as curcumin effectively reduced HIV-1 gp120-mediated elevation of the delayed rectification and transient outward K(+) channel current in neurons. We conclude that HIV-1 gp120 increases ROS, TNF-α and MCP-1 production in microglia, and induces cortical neuron apoptosis by affecting the delayed rectification and transient outward K(+) channel current. Curcumin reduces production of ROS and inflammatory mediators in HIV-1-gp120-stimulated microglia, and protects cortical neurons against HIV-1-mediated apoptosis, most likely through inhibition of HIV-1 gp120-induced elevation of the delayed rectification and transient outward K(+) current.
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Affiliation(s)
- Luyan Guo
- Department of Gynaecology and Obstetrics, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
- Department of Pathophysiology, Key Laboratory of the State Administration of Traditional Chinese Medicine, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Institute of Brain Research, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Guangdong-Hongkong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, Guangdong Province, China
| | - Yanyan Xing
- Department of Pathophysiology, Key Laboratory of the State Administration of Traditional Chinese Medicine, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Institute of Brain Research, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Guangdong-Hongkong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, Guangdong Province, China
| | - Rui Pan
- Department of Orthopedics, the First Affiliated Hospital, Medical College of Jinan University, Guangzhou, Guangdong Province, China
| | - Mingliang Jiang
- Department of Pathophysiology, Key Laboratory of the State Administration of Traditional Chinese Medicine, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Institute of Brain Research, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Guangdong-Hongkong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, Guangdong Province, China
| | - Zheng Gong
- Department of Pathophysiology, Key Laboratory of the State Administration of Traditional Chinese Medicine, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Institute of Brain Research, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Guangdong-Hongkong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, Guangdong Province, China
| | - Liqing Lin
- Department of Pathophysiology, Key Laboratory of the State Administration of Traditional Chinese Medicine, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Institute of Brain Research, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Guangdong-Hongkong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, Guangdong Province, China
| | - Junbing Wang
- Department of Pathophysiology, Key Laboratory of the State Administration of Traditional Chinese Medicine, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Institute of Brain Research, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Guangdong-Hongkong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, Guangdong Province, China
| | - Guoyin Xiong
- Department of Pathophysiology, Key Laboratory of the State Administration of Traditional Chinese Medicine, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Institute of Brain Research, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Guangdong-Hongkong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, Guangdong Province, China
| | - Jun Dong
- Department of Pathophysiology, Key Laboratory of the State Administration of Traditional Chinese Medicine, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Institute of Brain Research, Medical College of Jinan University, Guangzhou, Guangdong Province, China
- Guangdong-Hongkong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, Guangdong Province, China
- * E-mail:
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Chen M, Sun HY, Hu P, Wang CF, Li BX, Li SJ, Li JJ, Tan HY, Gao TM. Activation of BKCa Channels Mediates Hippocampal Neuronal Death After Reoxygenation and Reperfusion. Mol Neurobiol 2013; 48:794-807. [DOI: 10.1007/s12035-013-8467-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 04/26/2013] [Indexed: 11/29/2022]
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Martín V, Vale C, Bondu S, Thomas OP, Vieytes MR, Botana LM. Differential effects of crambescins and crambescidin 816 in voltage-gated sodium, potassium and calcium channels in neurons. Chem Res Toxicol 2013; 26:169-78. [PMID: 23270282 DOI: 10.1021/tx3004483] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Crambescins and crambescidins are two families of guanidine alkaloids from the marine sponge Crambe crambe. Although very little information about their biological effect has been reported, it is known that crambescidin 816 (Cramb816) blocks calcium channels in a neuroblastoma X glioma cell line. Taking this into account, and the fact that ion channels are frequent targets for natural toxins, we examined the effect of Cramb816 and three compounds from the crambescin family, norcrambescin A2 (NcrambA2), crambescin A2 (CrambA2), and crambescin C1 (CrambC1), in the main voltage-dependent ion channels in neurons: sodium, potassium, and calcium channels. Electrophysiological recordings of voltage gated sodium, potassium, and calcium currents, in the presence of these guanidine alkaloids, were performed in cortical neurons from embryonic mice. Different effects were discovered: crambescins inhibited K(+) currents with the following potency: NcrambA2 > CrambC1 > CrambA2, while Cramb816 lacked an effect. Only CrambC1 and Cramb816 partially blocked Na(+) total current. However, Cramb816 partially blocked Ca(2+) , while NcrambA2 did not. Since the blocking effect of Cramb816 on calcium currents has not been previously reported in detail, we further pharmacologically isolated the two main fractions of HVA Ca(2+) channels in neurons and investigated the Cramb816 effect on them. Here, we revealed that Cav1 or L-type calcium channels are the main target for Cramb816. These two families of guanidine alkaloids clearly showed a structure-activity relationship with the crambescins acting on voltage-gated potassium channels, while Cramb816 blocks the voltage-gated calcium channel Cav1 with higher potency than nifedipine. The novel evidence that Cramb816 partially blocked CaV and NaV channels in neurons suggests that this compound might be involved in decreasing the neurotransmitter release and synaptic transmission in the central nervous system. The findings presented here provide the first detailed approach on the different effects of crambescin and crambescidin compounds in voltage-gated sodium, potassium, and calcium channels in neurons and thus provide a basis for future studies.
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Affiliation(s)
- Víctor Martín
- Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela , Lugo, Spain
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Abstract
SIGNIFICANCE Evidence of the ability of the gasotransmitter hydrogen sulfide (H(2)S) to serve as a regulator of many physiological functions, including control of blood pressure, regulation of cardiac function, protection of neurons, and cardiomyocytes against apoptosis, and in pain sensation is accumulating. However, the mechanisms accounting for its many actions are not yet well understood. RECENT ADVANCES Following the pioneering studies of the regulation of N-methyl-d-aspartate receptors and ATP-sensitive K(+) channels by H(2)S, data continue to emerge indicating that H(2)S modulates other ion channel types. This article reviews the numerous, yet diverse, types of ion channels now reported to be regulated by H(2)S. CRITICAL ISSUES Currently, a critical issue within this field is to determine the mechanisms by which H(2)S regulates ion channels, as well as other target proteins. Mechanisms to account for regulation include direct channel protein sulfhydration, channel redox modulation, effects mediated by interactions with other gasotransmitters (carbon monoxide and nitric oxide), and indirect effects, such as modulation of channel-regulating kinases. Through such modulation of ion channels, novel roles for H(2)S are emerging as important factors in both physiological and pathological processes. FUTURE DIRECTIONS Increasing current awareness and understanding of the roles and mechanisms of action of ion channel regulation by H(2)S will open opportunities for therapeutic intervention with clear clinical benefits, and inform future therapies. In addition, more sensitive methods for detecting relevant physiological concentrations of H(2)S will allow for clarification of specific ion channel regulation with reference to physiological or pathophysiological settings.
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Affiliation(s)
- Chris Peers
- Division of Cardiovascular and Neuronal Remodelling, Faculty of Medicine and Health, Leeds Institute for Genetics Health and Therapeutics, University of Leeds, Leeds, United Kingdom.
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Abuhassan K, Coyle D, Maguire L. Employing neuronal networks to investigate the pathophysiological basis of abnormal cortical oscillations in Alzheimer's disease. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:2065-8. [PMID: 22254743 DOI: 10.1109/iembs.2011.6090382] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
This paper describes an investigation into the pathophysiological causes of abnormal cortical oscillations in Alzheimer's disease (AD) using two heterogeneous neuronal network models. The effect of excitatory circuit disruption on the beta band power (13-30 Hz) using a conductance-based network model of 200 neurons is assessed. Then, the neural correlates of abnormal cortical oscillations in different frequency bands based on a larger network model of 1000 neurons consisting of different types of cortical neurons is also analyzed. The results show that, despite the heterogeneity of the network models, the beta band power is significantly affected by excitatory neural and synaptic loss. Secondly, the results of modeling a functional impairment in the excitatory circuit shows that beta band power exhibits the most decrease compared with other bands. Previous biological experiments on different types of cultural excitatory neurons show that cortical neuronal death is mediated by dysfunctional ionic behavior that might specifically contribute to the pathogenesis of p-amyloid peptide (Ap)-induced neuronal death in AD. Our study also shows that beta band power was the first affected component when the modeled excitatory circuit begins to lose neurons and synapses. Alpha (8-12 Hz), gamma (30-50 Hz) and Full frequency (1-70 Hz) band power are affected in a later stage when more severe synaptic loss occurs.
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Affiliation(s)
- Kamal Abuhassan
- Intelligent Systems Research Centre, University of Ulster, UK.
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Wang Y, Song M, Hou L, Yu Z, Chen H. The newly identified K+ channel blocker talatisamine attenuates beta-amyloid oligomers induced neurotoxicity in cultured cortical neurons. Neurosci Lett 2012; 518:122-7. [DOI: 10.1016/j.neulet.2012.04.067] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 04/24/2012] [Accepted: 04/26/2012] [Indexed: 01/09/2023]
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Alonso E, Fuwa H, Vale C, Suga Y, Goto T, Konno Y, Sasaki M, LaFerla FM, Vieytes MR, Giménez-Llort L, Botana LM. Design and synthesis of skeletal analogues of gambierol: attenuation of amyloid-β and tau pathology with voltage-gated potassium channel and N-methyl-D-aspartate receptor implications. J Am Chem Soc 2012; 134:7467-79. [PMID: 22475455 DOI: 10.1021/ja300565t] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Gambierol is a potent neurotoxin that belongs to the family of marine polycyclic ether natural products and primarily targets voltage-gated potassium channels (K(v) channels) in excitable membranes. Previous work in the chemistry of marine polycyclic ethers has suggested the critical importance of the full length of polycyclic ether skeleton for potent biological activity. Although we have previously investigated structure-activity relationships (SARs) of the peripheral functionalities of gambierol, it remained unclear whether the whole polycyclic ether skeleton is needed for its cellular activity. In this work, we designed and synthesized two truncated skeletal analogues of gambierol comprising the EFGH- and BCDEFGH-rings of the parent compound, both of which surprisingly showed similar potency to gambierol on voltage-gated potassium channels (K(v)) inhibition. Moreover, we examined the effect of these compounds in an in vitro model of Alzheimer's disease (AD) obtained from triple transgenic (3xTg-AD) mice, which expresses amyloid beta (Aβ) accumulation and tau hyperphosphorylation. In vitro preincubation of the cells with the compounds resulted in significant inhibition of K(+) currents, a reduction in the extra- and intracellular levels of Aβ, and a decrease in the levels of hyperphosphorylated tau. In addition, pretreatment with these compounds reduced the steady-state level of the N-methyl-D-aspartate (NMDA) receptor subunit 2A without affecting the 2B subunit. The involvement of glutamate receptors was further suggested by the blockage of the effect of gambierol on tau hyperphosphorylation by glutamate receptor antagonists. The present study constitutes the first discovery of skeletally simplified, designed polycyclic ethers with potent cellular activity and demonstrates the utility of gambierol and its synthetic analogues as chemical probes for understanding the function of K(v) channels as well as the molecular mechanism of Aβ metabolism modulated by NMDA receptors.
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Affiliation(s)
- Eva Alonso
- Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, Lugo, Spain
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Abuhassan K, Coyle D, Maguire LP. Investigating the neural correlates of pathological cortical networks in Alzheimer's disease using heterogeneous neuronal models. IEEE Trans Biomed Eng 2011; 59:890-6. [PMID: 22207633 DOI: 10.1109/tbme.2011.2181843] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This paper describes an investigation into the pathophysiological causes of abnormal cortical oscillations in Alzheimer's disease (AD) using two heterogeneous neuronal network models. The effect of excitatory circuit disruption on the beta band power (13-30 Hz) using a conductance-based network model of 200 neurons is assessed. Then, the neural correlates of abnormal cortical oscillations in different frequency bands based on a larger network model of 1000 neurons consisting of different types of cortical neurons are also analyzed. EEG studies in AD patients have shown that beta band power (13-30 Hz) decreased in the early stages of the disease with a parallel increase in theta band power (4-7 Hz). This abnormal change progresses with the later stages of the disease but with decreased power spectra in other fast frequency bands plus an increase in delta band power (1-3 Hz). Our results show that, despite the heterogeneity of the network models, the beta band power is significantly affected by excitatory neural and synaptic loss. Second, the results of modeling a functional impairment in the excitatory circuit shows that beta band power exhibits the most decrease compared with other bands. Previous biological experiments on different types of cultural excitatory neurons show that cortical neuronal death is mediated by dysfunctional ionic behavior that might specifically contribute to the pathogenesis of β-amyloid-peptide-induced neuronal death in AD. Our study also shows that beta band power was the first affected component when the modeled excitatory circuit begins to lose neurons and synapses.
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Affiliation(s)
- Kamal Abuhassan
- Intelligent Systems Research Centre, University of Ulster, Derry, UK.
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Duan JJ, Wang Q, Deng CY, Kuang SJ, Chen RZ, Tao L. Effects of carvedilol on delayed rectifier and transient inactivating potassium currents in rat hippocampal CA1 neurons. Clin Exp Pharmacol Physiol 2011; 37:996-1003. [PMID: 20626758 DOI: 10.1111/j.1440-1681.2010.05427.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
1. The aims of the present study were to investigate the mechanism(s) underlying the protective effect of carvedilol against neural damage. 2. The transient inactivating potassium current (I(A) ) and the delayed rectifier potassium current (I(K) ) in rat hippocampal CA1 pyramidal neurons were recorded using whole-cell patch-clamp techniques. 3. Carvedilol (0.1-3 μmol/L) significantly inhibited I(K) with an IC(50) of 1.3 μmol/L and the inhibition was voltage independent. Over the same concentration range, carvedilol had no effect on the amplitude of I(A). At 1 μmol/L, carvedilol did not significantly change the steady state activation curves of I(A) and I(K), but did negatively shift their steady state inactivation curves. Recovery from inactivation was slowed for both I(A) and I(K). The inhibitory effect of carvedilol on I(K) was not affected by the adrenoceptor agonists phenylephrine and prazosin or the adrenoceptor antagonist isoproterenol, but propranolol was able to shift the dose-response curve of carvedilol for I(K) to the right. 4. Because I(K) is the main pathway for loss of intracellular potassium from depolarized neurons, selective obstruction of I(K) by carvedilol could be useful for neuroprotection.
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Affiliation(s)
- Jing-Jing Duan
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
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Zou X, Coyle D, Wong-Lin K, Maguire L. Computational study of hippocampal-septal theta rhythm changes due to β-amyloid-altered ionic channels. PLoS One 2011; 6:e21579. [PMID: 21720560 PMCID: PMC3123375 DOI: 10.1371/journal.pone.0021579] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 06/02/2011] [Indexed: 01/04/2023] Open
Abstract
Electroencephagraphy (EEG) of many dementia patients has been characterized by an increase in low frequency field potential oscillations. One of the characteristics of early stage Alzheimer's disease (AD) is an increase in theta band power (4-7 Hz). However, the mechanism(s) underlying the changes in theta oscillations are still unclear. To address this issue, we investigate the theta band power changes associated with β-Amyloid (Aβ) peptide (one of the main markers of AD) using a computational model, and by mediating the toxicity of hippocampal pyramidal neurons. We use an established biophysical hippocampal CA1-medial septum network model to evaluate four ionic channels in pyramidal neurons, which were demonstrated to be affected by Aβ. They are the L-type Ca²⁺ channel, delayed rectifying K⁺ channel, A-type fast-inactivating K⁺ channel and large-conductance Ca²⁺-activated K⁺ channel. Our simulation results demonstrate that only the Aβ inhibited A-type fast-inactivating K⁺ channel can induce an increase in hippocampo-septal theta band power, while the other channels do not affect theta rhythm. We further deduce that this increased theta band power is due to enhanced synchrony of the pyramidal neurons. Our research may elucidate potential biomarkers and therapeutics for AD. Further investigation will be helpful for better understanding of AD-induced theta rhythm abnormalities and associated cognitive deficits.
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Affiliation(s)
- Xin Zou
- Intelligent Systems Research Centre, University of Ulster Magee Campus, Derry, Northern Ireland, United Kingdom.
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Ray S, Howells C, Eaton ED, Butler CW, Shabala L, Adlard PA, West AK, Bennett WR, Guillemin GJ, Chung RS. Tg2576 cortical neurons that express human Ab are susceptible to extracellular Aβ-induced, K+ efflux dependent neurodegeneration. PLoS One 2011; 6:e19026. [PMID: 21556141 PMCID: PMC3083396 DOI: 10.1371/journal.pone.0019026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Accepted: 03/13/2011] [Indexed: 11/25/2022] Open
Abstract
Background One of the key pathological features of AD is the formation of insoluble amyloid plaques. The major constituent of these extracellular plaques is the beta-amyloid peptide (Aβ), although Aβ is also found to accumulate intraneuronally in AD. Due to the slowly progressive nature of the disease, it is likely that neurons are exposed to sublethal concentrations of both intracellular and extracellular Aβ for extended periods of time. Results In this study, we report that daily exposure to a sublethal concentration of Aβ1-40 (1 µM) for six days induces substantial apoptosis of cortical neurons cultured from Tg2576 mice (which express substantial but sublethal levels of intracellular Aβ). Notably, untreated Tg2576 neurons of similar age did not display any signs of apoptosis, indicating that the level of intracellular Aβ present in these neurons was not the cause of toxicity. Furthermore, wildtype neurons did not become apoptotic under the same chronic Aβ1-40 treatment. We found that this apoptosis was linked to Tg2576 neurons being unable to maintain K+ homeostasis following Aβ treatment. Furthermore, blocking K+ efflux protected Tg2576 neurons from Aβ-induced neurotoxicity. Interestingly, chronic exposure to 1 µM Aβ1-40 caused the generation of axonal swellings in Tg2576 neurons that contained dense concentrations of hyperphosphorylated tau. These were not observed in wildtype neurons under the same treatment conditions. Conclusions Our data suggest that when neurons are chronically exposed to sublethal levels of both intra- and extra-cellular Aβ, this causes a K+-dependent neurodegeneration that has pathological characteristics similar to AD.
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Affiliation(s)
- Shannon Ray
- NeuroRepair Group, Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia
| | - Claire Howells
- NeuroRepair Group, Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia
| | - Emma D. Eaton
- NeuroRepair Group, Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia
| | - Chris W. Butler
- NeuroRepair Group, Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia
| | - Lana Shabala
- NeuroRepair Group, Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia
| | - Paul A. Adlard
- Synaptic Neurobiology Lab, Mental Health Research Institute, Melbourne, Victoria, Australia
| | - Adrian K. West
- NeuroRepair Group, Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia
| | - William R. Bennett
- NeuroRepair Group, Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia
| | - Gilles J. Guillemin
- Neuroinflammation Group, University of New South Wales, Sydney, New South Wales, Australia
| | - Roger S. Chung
- NeuroRepair Group, Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia
- * E-mail:
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Ziyatdinova S, Gurevicius K, Kutchiashvili N, Bolkvadze T, Nissinen J, Tanila H, Pitkänen A. Spontaneous epileptiform discharges in a mouse model of Alzheimer's disease are suppressed by antiepileptic drugs that block sodium channels. Epilepsy Res 2011; 94:75-85. [DOI: 10.1016/j.eplepsyres.2011.01.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 01/03/2011] [Accepted: 01/08/2011] [Indexed: 11/30/2022]
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Yuan H, Wang WP, Feng N, Wang L, Wang XL. Donepezil attenuated oxygen-glucose deprivation insult by blocking Kv2.1 potassium channels. Eur J Pharmacol 2011; 657:76-83. [PMID: 21300054 DOI: 10.1016/j.ejphar.2011.01.054] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 01/06/2011] [Accepted: 01/25/2011] [Indexed: 10/18/2022]
Abstract
Excessive K(+) efflux via activated voltage-gated K(+) channels (Kv channels) and the consequent intracellular K(+) depletion during and after ischemia/hypoxia induced long-lasting membrane depolarization promotes neuronal apoptosis. Although it has been suggested as an important potassium channel subtype in oxidative stress induced neuron apoptosis, whether Kv2.1 mediates ischemic apoptosis remains undefined. In the present study, the role of Kv2.1 played in hypoxia/anoxia induced cell apoptosis and correlated protective effect of donepezil were evaluated. Kv2.1 transfected HEK293 cell line (Kv2.1/HEK293) was used to study oxygen-glucose deprivation (OGD) induced cell apoptosis. We found Kv2.1 transfection increased the vulnerability of HEK293 cells to OGD insult, blocking Kv2.1 potassium channel by tetraethylammonium (TEA, 10mM) could attenuated OGD induced Kv2.1/HEK293 cell apoptosis significantly. OGD slightly reduced Kv2.1 currents without affecting channel kinetic activity. However, the membrane potential of Kv2.1/HEK293 cells depolarized to around 0mV after OGD treatment, a potential which could activated Kv2.1 persistently. Donepezil blocked Kv2.1 currents in a dose-dependent manner (IC(50)=7.59μM). Under OGD condition, donepezil (30μM) effectively inhibited Kv2.1 currents by accelerating channel inactivation and decreased Kv2.1/HEK293 cell apoptosis rate. In conclusion, our study revealed both the conducting role of Kv2.1 in OGD induced cell apoptosis and the importance of Kv2.1 as a target for neuronal protection. In addition, besides anti-acetylcholinesterase activity, Kv2.1 blockade capability of donepezil may attribute to its neuroprotective effects against ischemic apoptosis.
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Affiliation(s)
- Hui Yuan
- Department of pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, No.1 Xiannongtan Street, Xuanwu District,Beijing 100050, China
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Troy CM, Akpan N, Jean YY. Regulation of Caspases in the Nervous System. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 99:265-305. [DOI: 10.1016/b978-0-12-385504-6.00007-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
This review focuses on recent developments in the use of natural products as therapeutics for Alzheimer's disease. The compounds span a diverse array of structural classes and are organized according to their mechanism of action, with the focus primarily on the major hypotheses. Overall, the review discusses more than 180 compounds and summarizes 400 references.
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Affiliation(s)
- Philip Williams
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
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