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Lorincz D, Drury HR, Smith DW, Lim R, Brichta AM. Aged mice are less susceptible to motion sickness and show decreased efferent vestibular activity compared to young adults. Brain Behav 2023; 13:e3064. [PMID: 37401009 PMCID: PMC10454360 DOI: 10.1002/brb3.3064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 04/13/2023] [Accepted: 05/03/2023] [Indexed: 07/05/2023] Open
Abstract
INTRODUCTION The efferent vestibular system (EVS) is a feedback circuit thought to modulate vestibular afferent activity by inhibiting type II hair cells and exciting calyx-bearing afferents in the peripheral vestibular organs. In a previous study, we suggested EVS activity may contribute to the effects of motion sickness. To determine an association between motion sickness and EVS activity, we examined the effects of provocative motion (PM) on c-Fos expression in brainstem efferent vestibular nucleus (EVN) neurons that are the source of efferent innervation in the peripheral vestibular organs. METHODS c-Fos is an immediate early gene product expressed in stimulated neurons and is a well-established marker of neuronal activation. To study the effects of PM, young adult C57/BL6 wild-type (WT), aged WT, and young adult transgenic Chat-gCaMP6f mice were exposed to PM, and tail temperature (Ttail ) was monitored using infrared imaging. After PM, we used immunohistochemistry to label EVN neurons to determine any changes in c-Fos expression. All tissue was imaged using laser scanning confocal microscopy. RESULTS Infrared recording of Ttail during PM indicated that young adult WT and transgenic mice displayed a typical motion sickness response (tail warming), but not in aged WT mice. Similarly, brainstem EVN neurons showed increased expression of c-Fos protein after PM in young adult WT and transgenic mice but not in aged cohorts. CONCLUSION We present evidence that motion sickness symptoms and increased activation of EVN neurons occur in young adult WT and transgenic mice in response to PM. In contrast, aged WT mice showed no signs of motion sickness and no change in c-Fos expression when exposed to the same provocative stimulus.
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Affiliation(s)
- David Lorincz
- School of Biomedical Sciences and PharmacyThe University of NewcastleCallaghanNew South WalesAustralia
| | - Hannah R. Drury
- School of Biomedical Sciences and PharmacyThe University of NewcastleCallaghanNew South WalesAustralia
| | - Doug W. Smith
- School of Biomedical Sciences and PharmacyThe University of NewcastleCallaghanNew South WalesAustralia
| | - Rebecca Lim
- School of Biomedical Sciences and PharmacyThe University of NewcastleCallaghanNew South WalesAustralia
| | - Alan M. Brichta
- School of Biomedical Sciences and PharmacyThe University of NewcastleCallaghanNew South WalesAustralia
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2
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Bhanukiran K, T A G, Krishnamurthy S, Singh SK, Hemalatha S. Discovery of multi-target directed 3-OH pyrrolidine derivatives through a semisynthetic approach from alkaloid vasicine for the treatment of Alzheimer's disease. Eur J Med Chem 2023; 249:115145. [PMID: 36706620 DOI: 10.1016/j.ejmech.2023.115145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 01/25/2023]
Abstract
Vasicine is a pyrroloquinazoline alkaloid, which has been isolated from the plant Adhatoda vasica. Naturally inspired semi-synthetic transformations were prepared using vasicine as a synthetic precursor to overcome Alzheimer's disease (AD). These semi-synthetic analogs exhibited stable interactions and were well resided at AChE and BChE active sites in in-silico studies. Further, in-vitro experiments were performed to assess the cholinesterase inhibitory activity and reduction of amyloid-beta (Aβ1-42) plaques potency, PAMPA assay permeability, and antioxidant activity, these findings suggested that compound VA10 can be a lead molecule among all the synthesized analogs. The compound VA10 binds towards AChE peripheral anionic site (PAS) property was established through propidium iodide displacement assay. Moreover, VA10 showed no notable cytotoxicity and exhibited neuroprotective nature on Aβ1-42 treated SH-SY5Y cell line. In addition, VA10 was found to be safe in rats, which was confirmed by acute oral toxicity studies. Furthermore, in-vivo studies suggested that compound VA10 (10 mg/kg, p.o) ameliorated the memory and cognition impairment in scopolamine-induced amnesia model and Aβ1-42 induced Alzheimer rat model. Ex-vivo studies of compound VA10 demonstrate improved ACh levels by inhibiting AChE activity in rat brain. Moreover, histopathological observations on rats brain sections indicate VA10 (10 mg/kg, p.o) recovered the neuronal cells at hippocampus region (DG, CA3, and CA1). These positive experimental data from in-silico, in-vitro and in-vivo studies, suggested that compound VA10 can be a lead compound for further preclinical development studies as a naturally derived alkaloid for anti-AD.
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Affiliation(s)
- Kancharla Bhanukiran
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, 221005, India
| | - Gajendra T A
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, 221005, India
| | - Sairam Krishnamurthy
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, 221005, India
| | - Sushil Kumar Singh
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, 221005, India
| | - Siva Hemalatha
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, 221005, India.
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Zhu H, Cong L, Chen Y, Chen S, Chen L, Huang Z, Zhou J, Xiao J, Huang Y, Su D. Efficiency of donepezil in elderly patients undergoing orthopaedic surgery due to underlying post-operative cognitive dysfunction: study protocol for a multicentre randomised controlled trial. Trials 2021; 22:688. [PMID: 34627332 PMCID: PMC8501596 DOI: 10.1186/s13063-021-05648-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 09/20/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Post-operative cognitive dysfunction (POCD) is an overarching term used to describe cognitive impairment identified in the preoperative or post-operative period. After surgical operations, older patients are particularly vulnerable to memory disturbances and other types of cognitive impairment. However, the pathogenesis of POCD remains unclear with no confirmed preventable or treatable strategy available. Our previous study demonstrated that the concentration of choline acetyl transferase in the cerebral spinal fluid was a predictive factor of POCD and that donepezil, which is an acetylcholinesterase inhibitor used in clinical settings for the treatment of Alzheimer's disease, can prevent learning and memory impairment after anaesthesia/surgery in aged mice. This study aimed to determine the critical role of donepezil in preventing cognitive impairment in elderly patients undergoing orthopaedic surgery. METHODS A multicentre, double-blind, placebo-controlled, crossover clinical trial will be performed to assess the efficacy of donepezil in elderly patients undergoing orthopaedic surgery. Participants (n = 360) will receive donepezil (5 mg once daily) or placebo from 1 day prior to surgery until 5 days after surgery. Neuropsychological tests will be measured at 1 day before the operation and 1 week, 1 month, 6 months and 1 year after the operation. DISCUSSION This research project mainly aimed to study the effects of donepezil in elderly patients undergoing orthopaedic surgery due to underlying POCD and to investigate the underlying physiological and neurobiological mechanisms of these effects. The results may provide important implications for the development of effective interfering strategies, specifically regarding cognitive dysfunction therapy using drugs. TRIAL REGISTRATION ClinicalTrials.gov NCT04423276 . Registered on 14 June 2020.
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Affiliation(s)
- Huichen Zhu
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127, China
| | - Lu Cong
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127, China
| | - Yi Chen
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127, China
| | - Shaoyi Chen
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127, China
| | - Lingke Chen
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127, China
| | - Zhenling Huang
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127, China
| | - Jie Zhou
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127, China
| | - Jie Xiao
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127, China
| | - Yonglei Huang
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127, China.
| | - Diansan Su
- Department of Anesthesiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127, China.
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Martinez JL, Zammit MD, West NR, Christian BT, Bhattacharyya A. Basal Forebrain Cholinergic Neurons: Linking Down Syndrome and Alzheimer's Disease. Front Aging Neurosci 2021; 13:703876. [PMID: 34322015 PMCID: PMC8311593 DOI: 10.3389/fnagi.2021.703876] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/17/2021] [Indexed: 12/31/2022] Open
Abstract
Down syndrome (DS, trisomy 21) is characterized by intellectual impairment at birth and Alzheimer’s disease (AD) pathology in middle age. As individuals with DS age, their cognitive functions decline as they develop AD pathology. The susceptibility to degeneration of a subset of neurons, known as basal forebrain cholinergic neurons (BFCNs), in DS and AD is a critical link between cognitive impairment and neurodegeneration in both disorders. BFCNs are the primary source of cholinergic innervation to the cerebral cortex and hippocampus, as well as the amygdala. They play a critical role in the processing of information related to cognitive function and are directly engaged in regulating circuits of attention and memory throughout the lifespan. Given the importance of BFCNs in attention and memory, it is not surprising that these neurons contribute to dysfunctional neuronal circuitry in DS and are vulnerable in adults with DS and AD, where their degeneration leads to memory loss and disturbance in language. BFCNs are thus a relevant cell target for therapeutics for both DS and AD but, despite some success, efforts in this area have waned. There are gaps in our knowledge of BFCN vulnerability that preclude our ability to effectively design interventions. Here, we review the role of BFCN function and degeneration in AD and DS and identify under-studied aspects of BFCN biology. The current gaps in BFCN relevant imaging studies, therapeutics, and human models limit our insight into the mechanistic vulnerability of BFCNs in individuals with DS and AD.
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Affiliation(s)
- Jose L Martinez
- Cellular and Molecular Biology Graduate Program, University of Wisconsin, Madison, WI, United States.,Waisman Center, University of Wisconsin, Madison, WI, United States
| | - Matthew D Zammit
- Waisman Center, University of Wisconsin, Madison, WI, United States.,Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
| | - Nicole R West
- Cellular and Molecular Biology Graduate Program, University of Wisconsin, Madison, WI, United States.,Waisman Center, University of Wisconsin, Madison, WI, United States
| | - Bradley T Christian
- Waisman Center, University of Wisconsin, Madison, WI, United States.,Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States.,Department of Psychiatry, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
| | - Anita Bhattacharyya
- Waisman Center, University of Wisconsin, Madison, WI, United States.,Department of Cellular and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
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Stark SM, Frithsen A, Stark CE. Age-related alterations in functional connectivity along the longitudinal axis of the hippocampus and its subfields. Hippocampus 2021; 31:11-27. [PMID: 32918772 PMCID: PMC8354549 DOI: 10.1002/hipo.23259] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 07/31/2020] [Accepted: 08/07/2020] [Indexed: 12/13/2022]
Abstract
Hippocampal circuit alterations that differentially affect hippocampal subfields are associated with age-related memory decline. Additionally, functional organization along the longitudinal axis of the hippocampus has revealed distinctions between anterior and posterior (A-P) connectivity. Here, we examined the functional connectivity (FC) differences between young and older adults at high-resolution within the medial temporal lobe network (entorhinal, perirhinal, and parahippocampal cortices), allowing us to explore how hippocampal subfield connectivity across the longitudinal axis of the hippocampus changes with age. Overall, we found reliably greater connectivity for younger adults than older adults between the hippocampus and parahippocampal cortex (PHC) and perirhinal cortex (PRC). This drop in functional connectivity was more pronounced in the anterior regions of the hippocampus than the posterior ones, consistent for each of the hippocampal subfields. Further, intra-hippocampal connectivity also reflected an age-related decrease in functional connectivity within the anterior hippocampus in older adults that was offset by an increase in posterior hippocampal functional connectivity. Interestingly, the anterior-posterior dysfunction in older adults between hippocampus and PHC was predictive of lure discrimination performance on the Mnemonic similarity task (MST), suggesting a role in memory performance. While age-related dysfunction within the hippocampal subfields has been well-documented, these results suggest that the age-related dysfunction in hippocampal connectivity across the longitudinal axis may also contribute significantly to memory decline in older adults.
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Affiliation(s)
- Shauna M. Stark
- Department of Neurobiology and Behavior, University of California Irvine
| | - Amy Frithsen
- Department of Neurobiology and Behavior, University of California Irvine
| | - Craig E.L. Stark
- Department of Neurobiology and Behavior, University of California Irvine
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Fabiani C, Antollini SS. Alzheimer's Disease as a Membrane Disorder: Spatial Cross-Talk Among Beta-Amyloid Peptides, Nicotinic Acetylcholine Receptors and Lipid Rafts. Front Cell Neurosci 2019; 13:309. [PMID: 31379503 PMCID: PMC6657435 DOI: 10.3389/fncel.2019.00309] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 06/25/2019] [Indexed: 12/17/2022] Open
Abstract
Biological membranes show lateral and transverse asymmetric lipid distribution. Cholesterol (Chol) localizes in both hemilayers, but in the external one it is mostly condensed in lipid-ordered microdomains (raft domains), together with saturated phosphatidyl lipids and sphingolipids (including sphingomyelin and glycosphingolipids). Membrane asymmetries induce special membrane biophysical properties and behave as signals for several physiological and/or pathological processes. Alzheimer’s disease (AD) is associated with a perturbation in different membrane properties. Amyloid-β (Aβ) plaques and neurofibrillary tangles of tau protein together with neuroinflammation and neurodegeneration are the most characteristic cellular changes observed in this disease. The extracellular presence of Aβ peptides forming senile plaques, together with soluble oligomeric species of Aβ, are considered the major cause of the synaptic dysfunction of AD. The association between Aβ peptide and membrane lipids has been extensively studied. It has been postulated that Chol content and Chol distribution condition Aβ production and posterior accumulation in membranes and, hence, cell dysfunction. Several lines of evidence suggest that Aβ partitions in the cell membrane accumulate mostly in raft domains, the site where the cleavage of the precursor AβPP by β- and γ- secretase is also thought to occur. The main consequence of the pathogenesis of AD is the disruption of the cholinergic pathways in the cerebral cortex and in the basal forebrain. In parallel, the nicotinic acetylcholine receptor has been extensively linked to membrane properties. Since its transmembrane domain exhibits extensive contacts with the surrounding lipids, the acetylcholine receptor function is conditioned by its lipid microenvironment. The nicotinic acetylcholine receptor is present in high-density clusters in the cell membrane where it localizes mainly in lipid-ordered domains. Perturbations of sphingomyelin or cholesterol composition alter acetylcholine receptor location. Therefore, Aβ processing, Aβ partitioning, and acetylcholine receptor location and function can be manipulated by changes in membrane lipid biophysics. Understanding these mechanisms should provide insights into new therapeutic strategies for prevention and/or treatment of AD. Here, we discuss the implications of lipid-protein interactions at the cell membrane level in AD.
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Affiliation(s)
- Camila Fabiani
- Instituto de Investigaciones Bioquímicas de Bahía Blanca CONICET-UNS, Bahía Blanca, Argentina.,Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - Silvia S Antollini
- Instituto de Investigaciones Bioquímicas de Bahía Blanca CONICET-UNS, Bahía Blanca, Argentina.,Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
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7
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Central cholinergic neuronal degeneration promotes the development of postoperative cognitive dysfunction. J Transl Med 2019; 99:1078-1088. [PMID: 30626892 DOI: 10.1038/s41374-018-0174-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 10/11/2018] [Accepted: 11/07/2018] [Indexed: 02/07/2023] Open
Abstract
Postoperative cognitive dysfunction (POCD) is consistently associated with increased morbidity and mortality. However, its mechanism remains poorly understood. We hypothesized that central cholinergic neuronal degeneration facilitates the development of POCD. The impact of anesthesia/surgery (appendectomy) on learning and memory and the levels of choline acetyltransferase (ChAT), acetylcholinesterase (AChE), vesicular acetylcholine transporter (VAChT), and choline transporter (CHT) in adult and aged mice were measured. Separate cohorts were analyzed after pretreatment with donepezil, an AChE inhibitor, in aged mice or with murine-p75-saporin (mu-p75-sap), a cholinergic-specific immunotoxin, in adult mice. Morris Water Maze was used to measure the learning and memory changes after anesthesia/surgery. Western blot was used to measure the changes in the protein levels of the biomarkers of the central cholinergic system. We found that anesthesia/surgery-induced memory decline and attenuation of central cholinergic biomarkers (ChAT and VAChT) in aged mice but not in adult mice. Donepezil pretreatment reduced central cholinergic impairment in the aged mice and prevented learning and memory declines after anesthesia/surgery. In contrast, when central cholinergic neurons were pre-injured with mu-p75-sap, cognitive dysfunction developed in the adult mice after anesthesia/surgery. These data suggest that central cholinergic neuronal degeneration facilitates the development of POCD.
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8
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Lammers F, Borchers F, Feinkohl I, Hendrikse J, Kant IMJ, Kozma P, Pischon T, Slooter AJC, Spies C, van Montfort SJT, Zacharias N, Zaborszky L, Winterer G. Basal forebrain cholinergic system volume is associated with general cognitive ability in the elderly. Neuropsychologia 2018; 119:145-156. [PMID: 30096414 PMCID: PMC6338214 DOI: 10.1016/j.neuropsychologia.2018.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 08/02/2018] [Accepted: 08/06/2018] [Indexed: 12/30/2022]
Abstract
OBJECTIVE At the present, it is unclear whether association of basal forebrain cholinergic system (BFCS) volume with cognitive performance exists in healthy as well as in cognitively impaired elderly subjects. Whereas one small study reported an association of BFCS volume with general cognitive ability 'g' in healthy ageing, effects on specific cognitive domains have only been found in subjects with cognitive decline. Here we aim to clarify whether an association of BFCS volume and 'g' is present in a larger sample of elderly subjects without obvious symptoms of dementia and whether similar associations can also be observed in specific cognitive domains. METHODS 282 pre-surgical patients from the BioCog study (aged 72.7 ± 4.9 years with a range of 65-87 years, 110 women) with a median MMSE score of 29 points (range 24-30) were investigated. BFCS and brain volume as well as brain parenchymal fraction were assessed in T1-weighted MR images using SPM12 and a probabilistic map of the BFCS. Neuropsychological assessment comprised the CANTAB cognitive battery and paper-and-pencil based tests. For data analysis, generalised linear models and quantile regression were applied. RESULTS Significant associations of BFCS volume with 'g' and several cognitive domains were found, with the strongest association found for 'g'. BFCS volume explained less variance in cognitive performance than brain volume. The association was not confounded by brain parenchymal fraction. Furthermore, the association of BFCS volume and 'g' was similar in high- and low-performers. CONCLUSION Our results extend previous study findings on BFCS volume associations with cognition in elderly subjects. Despite the observed associations of BFCS volume and cognitive performance, this association seems to reflect a more general association of brain volume and cognition. Accordingly, a specific association of BFCS volume and cognition in non-demented elderly subjects is questionable.
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Affiliation(s)
- Florian Lammers
- Department of Anaesthesiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Augustenburger Platz 1, 13353 Berlin, Germany; Pharmaimage Biomarker Solutions GmbH, Robert-Rössle-Straße 10, 13125 Berlin, Germany.
| | - Friedrich Borchers
- Department of Anaesthesiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Insa Feinkohl
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Jeroen Hendrikse
- Department of Radiology and Brain Center Rudolf Magnus, University Medical Centre Utrecht, Utrecht University Heidelberglaan 100, 3584 CX Utrecht, Netherlands
| | - Ilse M J Kant
- Department of Intensive Care Medicine and Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University Heidelberglaan 100, 3584 CX Utrecht, Netherlands
| | - Petra Kozma
- Department of Anaesthesiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Tobias Pischon
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125 Berlin, Germany; Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Germany; MDC/BIH Biobank, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), and Berlin Institute of Health (BIH), Berlin, Germany
| | - Arjen J C Slooter
- Department of Intensive Care Medicine and Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University Heidelberglaan 100, 3584 CX Utrecht, Netherlands
| | - Claudia Spies
- Department of Anaesthesiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Simone J T van Montfort
- Department of Intensive Care Medicine and Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University Heidelberglaan 100, 3584 CX Utrecht, Netherlands
| | - Norman Zacharias
- Department of Anaesthesiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Augustenburger Platz 1, 13353 Berlin, Germany; Pharmaimage Biomarker Solutions GmbH, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Laszlo Zaborszky
- Center for Molecular and Behavioral Neuroscience, Rutgers The State University of New Jersey, 197 University Avenue, Newark, NJ 07102, USA
| | - Georg Winterer
- Department of Anaesthesiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Augustenburger Platz 1, 13353 Berlin, Germany; Pharmaimage Biomarker Solutions GmbH, Robert-Rössle-Straße 10, 13125 Berlin, Germany
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Hunter S, Smailagic N, Brayne C. Dementia Research: Populations, Progress, Problems, and Predictions. J Alzheimers Dis 2018; 64:S119-S143. [DOI: 10.3233/jad-179927] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Sally Hunter
- Institute of Public Health, University of Cambridge, Cambridge, UK
| | - Nadja Smailagic
- Institute of Public Health, University of Cambridge, Cambridge, UK
| | - Carol Brayne
- Institute of Public Health, University of Cambridge, Cambridge, UK
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10
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Ruhal P, Dhingra D. Inosine improves cognitive function and decreases aging-induced oxidative stress and neuroinflammation in aged female rats. Inflammopharmacology 2018; 26:1317-1329. [PMID: 29619603 DOI: 10.1007/s10787-018-0476-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 03/27/2018] [Indexed: 12/12/2022]
Abstract
In the present study, the effect of inosine was evaluated on learning and memory of 18 months old aged female rats. Inosine (50, 100 and 200 mg/kg; i.p.) was administered to separate groups of rats for 15 successive days. Donepezil (1 mg/kg; i.p.), an acetylcholinesterase inhibitor, was used as a standard drug. Behavioral models such as Morris water maze and elevated plus maze were used to evaluate the effect of drugs on learning and memory of rats. After behavioral studies, animals were killed and their brain was isolated and further processed for estimation of various biochemical parameters such as acetylcholinesterase activity, oxidative stress markers, proinflammatory marker and histological examinations. Inosine (100 and 200 mg/kg) significantly improved learning and memory of aged rats. Further, inosine significantly reduced lipid peroxidation and nitrite, and increased the levels of reduced glutathione and superoxide dismutase. However, no significant difference in AChEs activity was observed in inosine-treated rats as compared to aged control rats. TNF-α level was found to be ameliorated in aged rats by inosine. Histopathological evaluation showed that inosine-treated aged rats have less number of pyknotic neurons in hippocampal CA1 region as compared to aged control rats. In conclusion, inosine significantly improved learning and memory of aged female rats possibly through its antioxidant as well as anti-inflammatory effect and improvement of neuronal survival in the hippocampal CA1 region. However, additional studies are required to further explore the downstream signaling pathways involved in the neuroprotective effect of inosine in aged animals.
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Affiliation(s)
- Poonam Ruhal
- Pharmacology Division, Department of Pharmaceutical Sciences, Guru Jambheshwar University of Science and Technology, Hisar, Haryana, 125001, India
| | - Dinesh Dhingra
- Pharmacology Division, Department of Pharmaceutical Sciences, Guru Jambheshwar University of Science and Technology, Hisar, Haryana, 125001, India.
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11
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Farajdokht F, Amani M, Mirzaei Bavil F, Alihemmati A, Mohaddes G, Babri S. Troxerutin protects hippocampal neurons against amyloid beta-induced oxidative stress and apoptosis. EXCLI JOURNAL 2017; 16:1081-1089. [PMID: 29285004 PMCID: PMC5735350 DOI: 10.17179/excli2017-526] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 07/17/2017] [Indexed: 01/19/2023]
Abstract
Alzheimer's disease (AD) is an age-related neurodegenerative disease linked with increased production and/or deposition of amyloid-beta (Aβ) in the brain. The aim of the present study was to investigate the possible neuroprotective effect of troxerutin on an animal model of Alzheimer's disease. Alzheimer model was induced by a single dose intracerebroventricular (ICV) injection of Aβ 1-42 (5 nmol/5 µl). Thereafter, troxerutin (300 mg/kg) was gavaged for 14 days. The hippocampal malondialdehyde (MDA) levels and enzymatic activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and acetylcholinesterase (AChE) were measured using enzyme-linked immunosorbent assay (ELISA) method. In addition, the number of apoptotic cells in the dentate gyrus (DG) was assessed by TUNEL kit. The results showed that ICV microinjection of Aβ 1-42 increased MDA levels, reduced SOD and GPx, and increased AChE activities in the hippocampus. Chronic administration of troxerutin significantly attenuated MDA levels and AChE activity and increased SOD and GPx activities in the hippocampus. Moreover, the number of apoptotic cells was decreased by troxerutin treatment. Taken together, our study demonstrated that troxerutin could increase the resistance of hippocampal neurons against apoptosis, at least in part, by diminishing the activity of AChE and oxidative stress. Therefore, troxerutin may have beneficial effects in the management of Alzheimer's disease.
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Affiliation(s)
- Fereshteh Farajdokht
- Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Amani
- Drug Applied Research Center of Tabriz University of Medical Sciences, Tabriz, Iran
| | - Fariba Mirzaei Bavil
- Drug Applied Research Center of Tabriz University of Medical Sciences, Tabriz, Iran
| | - Alireza Alihemmati
- Drug Applied Research Center of Tabriz University of Medical Sciences, Tabriz, Iran
| | - Gisou Mohaddes
- Drug Applied Research Center of Tabriz University of Medical Sciences, Tabriz, Iran
| | - Shirin Babri
- Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran
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Singh Y, Gupta G, Shrivastava B, Dahiya R, Tiwari J, Ashwathanarayana M, Sharma RK, Agrawal M, Mishra A, Dua K. Calcitonin gene-related peptide (CGRP): A novel target for Alzheimer's disease. CNS Neurosci Ther 2017; 23:457-461. [PMID: 28417590 PMCID: PMC6492742 DOI: 10.1111/cns.12696] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/11/2017] [Accepted: 03/17/2017] [Indexed: 12/22/2022] Open
Abstract
Alzheimer's disease (AD) is leading cause of death among older characterized by neurofibrillary tangles, oxidative stress, progressive neuronal deficits, and increased levels of amyloid-β (Aβ) peptides. Cholinergic treatment could be the best suitable physiological therapy for AD. Calcitonin gene-related peptide (CGRP) is a thirty-seven-amino acid regulatory neuropeptide resulting from different merging of the CGRP gene, which also includes adrenomedullin, amylin, calcitonin, intermedin, and calcitonin receptor-stimulating peptide. It is a proof for a CGRP receptor within nucleus accumbens of brain that is different from either the CGRP1 or CGRP2 receptor in which it demonstrates similar high-affinity binding for salmon calcitonin, CGRP, and amylin, a possession which is not shared by any extra CGRP receptors. Binding of CGRP to its receptor increases activated cAMP-dependent pkA and PI3 kinase, resulting in N-terminal fragments that are shown to exert complex inhibitory as well facilitator actions on nAChRs. Fragments such as CGRP1-4, CGRP1-5, and CGRP1-6 rapidly as well as reversibly improve agonist sensitivity of nAChRs without straight stimulating those receptors and produce the Ca2+ -induced intracellular Ca2+ mobilization. Renin-angiotensin-aldosterone system (RAAS)-activated angiotensin-type (AT4) receptor is also beneficial in AD. It has been suggested that exogenous administration of CGRP inhibits infiltration of macrophages and expression of various inflammatory mediators such as NFkB, IL-1b, TNF-α, iNOS, matrix metalloproteinase (MMP)-9, and cell adhesion molecules like intercellular adhesion molecule (ICAM)-1 which attenuates consequence of inflammation in AD. Donepezil, a ChEI, inhibits acetylcholinesterase and produces angiogenesis and neurogenesis, in the dentate gyrus of the hippocampus of WT mice after donepezil administration. However, none of the results discovered in CGRP-knockout mice and WT mice exposed to practical denervation. Therefore, selective agonists of CGRP receptors may become the potential candidates for treatment of AD.
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Affiliation(s)
- Yogendra Singh
- School of PharmacyJaipur National UniversityJagatpuraJaipurIndia
| | - Gaurav Gupta
- School of PharmacyJaipur National UniversityJagatpuraJaipurIndia
- School of Medicine and Public HealthUniversity of NewcastleNewcastleNSWAustralia
| | | | - Rajiv Dahiya
- Laboratory of Peptide Research and DevelopmentSchool of Pharmacy, The University of the West IndiesSt. Augustine, Trinidad & TobagoWest Indies
| | - Juhi Tiwari
- School of PharmacyJaipur National UniversityJagatpuraJaipurIndia
| | | | | | - Mohit Agrawal
- School of pharmacySuresh Gyan Vihar UniversityJaipurIndia
| | - Anurag Mishra
- School of pharmacySuresh Gyan Vihar UniversityJaipurIndia
| | - Kamal Dua
- Discipline of PharmacyGraduate School of HealthUniversity of Technology SydneySydneyNSWAustralia
- School of Biomedical Sciences and PharmacyUniversity of NewcastleNewcastleNSWAustralia
- School of Pharmaceutical SciencesShoolini UniversitySolanHimachal PradeshIndia
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Serotonin 5-HT 6 Receptor Antagonists in Alzheimer's Disease: Therapeutic Rationale and Current Development Status. CNS Drugs 2017; 31:19-32. [PMID: 27914038 DOI: 10.1007/s40263-016-0399-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia in elderly people. Because of the lack of effective treatments for this illness, research focused on identifying compounds that restore cognition and functional impairments in patients with AD is a very active field. Since its discovery in 1993, the serotonin 5-HT6 receptor has received increasing attention, and a growing number of studies supported 5-HT6 receptor antagonism as a target for improving cognitive dysfunction in AD. This article reviews the rationale behind investigations into the targeting of 5-HT6 receptors as a symptomatic treatment for cognitive and/or behavioral symptoms of AD. In addition to describing the available clinical evidence, this article also describes the purported biochemical and neurochemical mechanisms of action by which 5-HT6 receptor antagonists could influence cognition, and the preclinical data supporting this therapeutic approach to AD. A large number of publications describing the development of ligands for this receptor have come to light and preclinical data indicate the procognitive efficacy of 5-HT6 receptor antagonists. Subsequently, the number of patents protecting 5-HT6 chemical entities has continuously grown. Some of these compounds have successfully undergone phase I clinical studies and have been further evaluated in clinical phase II trials with variable success. Phase II studies have also revealed the potential of combining 5-HT6 receptor antagonism and cholinesterase inhibition. Two of these antagonists, idalopirdine and RVT-101, have been further developed into ongoing phase III clinical trials. Overall, 5-HT6 receptor antagonists can reasonably be regarded as potential drug candidates for the treatment of AD.
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Ahmed T, Zahid S, Mahboob A, Farhat SM. Cholinergic System and Post-translational Modifications: An Insight on the Role in Alzheimer's Disease. Curr Neuropharmacol 2017; 15:480-494. [PMID: 27012953 PMCID: PMC5543671 DOI: 10.2174/1570159x14666160325121145] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 12/02/2015] [Accepted: 03/03/2016] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is the most common form of old age dementia. The formation of amyloid plaques (Aβ), neurofibrillary tangles and loss of basal forebrain cholinergic neurons are the hallmark events in the pathology of AD. LITERATURE REVIEW Cholinergic system is one of the most important neurotransmitter system involved in learning and memory which preferentially degenerates in the initial stages of AD. Activation of cholinergic receptors (muscarinic and nicotinic) activates multiple pathways which result in post translational modifications (PTMs) in multiple proteins which bring changes in nervous system. Cholinergic receptors-mediated PTMs "in-part" substantially affect the biosynthesis, proteolysis, degradation and expression of many proteins and in particular, amyloid precursor protein (APP). APP is subjected to several PTMs (proteolytic processing, glycosylation, sulfation, and phosphorylation) during its course of processing, resulting in Aβ deposition, leading to AD. Aβ also alters the PTMs of tau which is a microtubule associated protein. Therefore, post-translationally modified tau and Aβ collectively aggravate the neuronal loss that leads to cholinergic hypofunction. CONCLUSION Despite the accumulating evidences, the interaction between cholinergic neurotransmission and the physiological significance of PTM events remain speculative and still needs further exploration. This review focuses on the role of cholinergic system and discusses the significance of PTMs in pathological progression of AD and highlights some important future directions.
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Affiliation(s)
- Touqeer Ahmed
- Neurobiology Laboratory, Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Sector H-12, Islamabad, 44000, Pakistan
| | - Saadia Zahid
- Neurobiology Laboratory, Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Sector H-12, Islamabad, 44000, Pakistan
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15
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Current pharmacotherapy and putative disease-modifying therapy for Alzheimer's disease. Neurol Sci 2016; 37:1403-35. [PMID: 27250365 DOI: 10.1007/s10072-016-2625-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 05/24/2016] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is an age-related neurodegenerative disease of the central nervous system correlated with the progressive loss of cognition and memory. β-Amyloid plaques, neurofibrillary tangles and the deficiency in cholinergic neurotransmission constitute the major hallmarks of the AD. Two major hypotheses have been implicated in the pathogenesis of AD namely the cholinergic hypothesis which ascribed the clinical features of dementia to the deficit cholinergic neurotransmission and the amyloid cascade hypothesis which emphasized on the deposition of insoluble peptides formed due to the faulty cleavage of the amyloid precursor protein. Current pharmacotherapy includes mainly the acetylcholinesterase inhibitors and N-methyl-D-aspartate receptor agonist which offer symptomatic therapy and does not address the underlying cause of the disease. The disease-modifying therapy has garnered a lot of research interest for the development of effective pharmacotherapy for AD. β and γ-Secretase constitute attractive targets that are focussed in the disease-modifying approach. Potentiation of α-secretase also seems to be a promising approach towards the development of an effective anti-Alzheimer therapy. Additionally, the ameliorative agents that prevent aggregation of amyloid peptide and also the ones that modulate inflammation and oxidative damage associated with the disease are focussed upon. Development in the area of the vaccines is in progress to combat the characteristic hallmarks of the disease. Use of cholesterol-lowering agents also is a fruitful strategy for the alleviation of the disease as a close association between the cholesterol and AD has been cited. The present review underlines the major therapeutic strategies for AD with focus on the new developments that are on their way to amend the current therapeutic scenario of the disease.
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Lammers F, Mobascher A, Musso F, Shah NJ, Warbrick T, Zaborszky L, Winterer G. Effects of Ncl. Basalis Meynert volume on the Trail-Making-Test are restricted to the left hemisphere. Brain Behav 2016; 6:e00421. [PMID: 27110442 PMCID: PMC4834944 DOI: 10.1002/brb3.421] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 09/17/2015] [Accepted: 11/03/2015] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Cortical acetylcholine released from cells in the basal forebrain facilitates cue detection and improves attentional performance. Cholinergic fibres to the cortex originate from the CH4 cell group, sometimes referred to as the Nucleus basalis of Meynert and the Nucleus subputaminalis of Ayala. The aim of this work was to investigate the effects of volumes of cholinergic nuclei on attention and executive function. METHODS The volumes of CH4 and CH4p subregions were measured in a subgroup of 38 subjects (33.5 ± 11 years, 20 females) from a population-based cohort study of smokers and never-smokers who have undergone additional MR imaging. To define regions of interest, we applied a DARTEL-based procedure implemented in SPM8 and a validated probabilistic map of the basal forebrain. Attention and executive function were measured with Trail-Making Test (TMT A+B) and Stroop-Task. RESULTS We found a quadratic effect of the left CH4 subregion on performance of the TMT. Extremely small as well as extremely large volumes are associated with poor test performance. CONCLUSIONS Our results indicate that a small CH4 volume predisposes for a hypocholinergic state, whereas an extremely large volume predisposes for a hypercholinergic state. Both extremes have detrimental effects on attention. Comparable nonlinear effects have already been reported in pharmacological studies on the effects cholinergic agonists on attention.
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Affiliation(s)
- Florian Lammers
- Department of Anaesthesiology and Surgical Intensive Care Medicine Charité - University Medicine Berlin Berlin Germany
| | - Arian Mobascher
- Department of Psychiatry University Hospital Mainz Mainz Germany
| | - Francesco Musso
- Department of Psychiatry Heinrich-Heine University Düsseldorf Germany
| | - Nadim Jon Shah
- Institute of Neuroscience & Medicine Research Centre Jülich Jülich Germany; Department of Neurology Faculty of Medicine RWTH Aachen University Aachen Germany
| | - Tracy Warbrick
- Institute of Neuroscience & Medicine Research Centre Jülich Jülich Germany
| | - Laszlo Zaborszky
- Centre for Molecular and Behavioral Neuroscience Rutgers The State University of New Jersey Newark New Jersey 07102
| | - Georg Winterer
- Experimental and Clinical Research Centre (ECRC) Charité - University Medicine Berlin Berlin Germany; Pharmaimage Biomarker Solutions GmbH Biotech Park Berlin-Buch Robert-Rössle-Str. 10 13125 Berlin Germany
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Findlay JA, Hamilton DL, Ashford MLJ. BACE1 activity impairs neuronal glucose oxidation: rescue by beta-hydroxybutyrate and lipoic acid. Front Cell Neurosci 2015; 9:382. [PMID: 26483636 PMCID: PMC4589671 DOI: 10.3389/fncel.2015.00382] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 09/14/2015] [Indexed: 11/13/2022] Open
Abstract
Glucose hypometabolism and impaired mitochondrial function in neurons have been suggested to play early and perhaps causative roles in Alzheimer's disease (AD) pathogenesis. Activity of the aspartic acid protease, beta-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1), responsible for beta amyloid peptide generation, has recently been demonstrated to modify glucose metabolism. We therefore examined, using a human neuroblastoma (SH-SY5Y) cell line, whether increased BACE1 activity is responsible for a reduction in cellular glucose metabolism. Overexpression of active BACE1, but not a protease-dead mutant BACE1, protein in SH-SY5Y cells reduced glucose oxidation and the basal oxygen consumption rate, which was associated with a compensatory increase in glycolysis. Increased BACE1 activity had no effect on the mitochondrial electron transfer process but was found to diminish substrate delivery to the mitochondria by inhibition of key mitochondrial decarboxylation reaction enzymes. This BACE1 activity-dependent deficit in glucose oxidation was alleviated by the presence of beta hydroxybutyrate or α-lipoic acid. Consequently our data indicate that raised cellular BACE1 activity drives reduced glucose oxidation in a human neuronal cell line through impairments in the activity of specific tricarboxylic acid cycle enzymes. Because this bioenergetic deficit is recoverable by neutraceutical compounds we suggest that such agents, perhaps in conjunction with BACE1 inhibitors, may be an effective therapeutic strategy in the early-stage management or treatment of AD.
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Affiliation(s)
- John A Findlay
- Division of Cardiovascular and Diabetes Medicine, School of Medicine, Ninewells Hospital and Medical School, University of Dundee Dundee, UK
| | - David L Hamilton
- Division of Cardiovascular and Diabetes Medicine, School of Medicine, Ninewells Hospital and Medical School, University of Dundee Dundee, UK
| | - Michael L J Ashford
- Division of Cardiovascular and Diabetes Medicine, School of Medicine, Ninewells Hospital and Medical School, University of Dundee Dundee, UK
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Grothe MJ, Heinsen H, Amaro E, Grinberg LT, Teipel SJ. Cognitive Correlates of Basal Forebrain Atrophy and Associated Cortical Hypometabolism in Mild Cognitive Impairment. Cereb Cortex 2015; 26:2411-2426. [PMID: 25840425 DOI: 10.1093/cercor/bhv062] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Degeneration of basal forebrain (BF) cholinergic nuclei is associated with cognitive decline, and this effect is believed to be mediated by neuronal dysfunction in the denervated cortical areas. MRI-based measurements of BF atrophy are increasingly being used as in vivo surrogate markers for cholinergic degeneration, but the functional implications of reductions in BF volume are not well understood. We used high-resolution MRI, fluorodeoxyglucose-positron emission tomography (PET), and neuropsychological test data of 132 subjects with mild cognitive impairment (MCI) and 177 cognitively normal controls to determine associations between BF atrophy, cortical hypometabolism, and cognitive deficits. BF atrophy in MCI correlated with both impaired memory function and attentional control deficits, whereas hippocampus volume was more specifically associated with memory deficits. BF atrophy was also associated with widespread cortical hypometabolism, and path analytic models indicated that hypometabolism in domain-specific cortical networks mediated the association between BF volume and cognitive dysfunction. The presence of cortical amyloid pathology, as assessed using AV45-PET, did not significantly interact with the observed associations. These data underline the potential of multimodal imaging markers to study structure-function-cognition relationships in the living human brain and provide important in vivo evidence for an involvement of the human BF in cortical activity and cognitive function.
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Affiliation(s)
- Michel J Grothe
- German Center for Neurodegenerative Diseases (DZNE), Rostock, Germany
| | - Helmut Heinsen
- Laboratory of Morphological Brain Research, Department of Psychiatry, University of Würzburg, Würzburg, Germany
| | | | - Lea T Grinberg
- Aging Brain Study Group, LIM-22, Department of Pathology, University of Sao Paulo Medical School, Sao Paulo, Brazil.,UCSF Memory and Aging Center, University of California - San Francisco, San Francisco, CA, USA
| | - Stefan J Teipel
- German Center for Neurodegenerative Diseases (DZNE), Rostock, Germany.,Department of Psychosomatic Medicine, University of Rostock, Rostock, Germany
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Iulita MF, Cuello AC. Nerve growth factor metabolic dysfunction in Alzheimer's disease and Down syndrome. Trends Pharmacol Sci 2014; 35:338-48. [PMID: 24962069 DOI: 10.1016/j.tips.2014.04.010] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 04/16/2014] [Accepted: 04/30/2014] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative condition and the most common type of amnestic dementia in the elderly. Individuals with Down syndrome (DS) are at increased risk of developing AD in adulthood as a result of chromosome 21 trisomy and triplication of the amyloid precursor protein (APP) gene. In both conditions, the central nervous system (CNS) basal forebrain cholinergic system progressively degenerates, and such changes contribute to the manifestation of cognitive decline and dementia. Given the strong dependency of these neurons on nerve growth factor (NGF), it was hypothesized that their atrophy was caused by NGF deficits. However, in AD, the synthesis of NGF is not affected at the transcript level and there is a marked increase in its precursor, proNGF. This apparent paradox remained elusive for many years. In this review, we discuss the recent evidence supporting a CNS deficit in the extracellular metabolism of NGF, both in AD and in DS brains. We describe the nature of this trophic disconnection and its implication for the atrophy of basal forebrain cholinergic neurons. We further discuss the potential of NGF pathway markers as diagnostic indicators of a CNS trophic disconnection.
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Affiliation(s)
- M Florencia Iulita
- Department of Pharmacology and Therapeutics, McGill University, Montreal, H3G1Y6, Canada
| | - A Claudio Cuello
- Department of Pharmacology and Therapeutics, McGill University, Montreal, H3G1Y6, Canada; Department of Anatomy and Cell Biology, McGill University, Montreal, H3G1Y6, Canada; Department of Neurology and Neurosurgery, McGill University, Montreal, H3G1Y6, Canada.
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Choi JHK, Kaur G, Mazzella MJ, Morales-Corraliza J, Levy E, Mathews PM. Early endosomal abnormalities and cholinergic neuron degeneration in amyloid-β protein precursor transgenic mice. J Alzheimers Dis 2013; 34:691-700. [PMID: 23254640 DOI: 10.3233/jad-122143] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Early endosomal changes, a prominent pathology in neurons early in Alzheimer's disease, also occur in neurons and peripheral tissues in Down syndrome. While in Down syndrome models increased amyloid-β protein precursor (AβPP) expression is known to be a necessary contributor on the trisomic background to this early endosomal pathology, increased AβPP alone has yet to be shown to be sufficient to drive early endosomal alterations in neurons. Comparing two AβPP transgenic mouse models, one that contains the AβPP Swedish K670N/M671L double mutation at the β-cleavage site (APP23) and one that has the AβPP London V717I mutation near the γ-cleavage site (APPLd2), we show significantly altered early endosome morphology in fronto-parietal neurons as well as enlargement of early endosomes in basal forebrain cholinergic neurons of the medial septal nucleus in the APP23 model, which has the higher levels of AβPP β-C-terminal fragment (βCTF) accumulation. Early endosomal changes correlate with a marked loss of the cholinergic population, which is consistent with the known dependence of the large projection cholinergic cells on endosome-mediated retrograde neurotrophic transport. Our findings support the idea that increased expression of AβPP and AβPP metabolites in neurons is sufficient to drive early endosomal abnormalities in vivo, and that disruption of the endocytic system is likely to contribute to basal forebrain cholinergic vulnerability.
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Lee YS, Danandeh A, Baratta J, Lin CY, Yu J, Robertson RT. Neurotrophic factors rescue basal forebrain cholinergic neurons and improve performance on a spatial learning test. Exp Neurol 2013; 249:178-86. [PMID: 24017996 DOI: 10.1016/j.expneurol.2013.08.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 08/05/2013] [Accepted: 08/22/2013] [Indexed: 12/25/2022]
Abstract
This study investigated whether animals sustaining experimental damage to the basal forebrain cholinergic system would benefit from treatment with exogenous neurotrophic factors. Specifically, we set out to determine whether neurotrophic factors would rescue damaged cholinergic neurons and improve behavioral performance on a spatial learning and memory task. Adult rats received bilateral injections of either saline (controls) or 192 IgG-saporin to damage basal forebrain cholinergic neurons (BFCNs). Two weeks later, animals received implants of an Alzet mini-pump connected to cannulae implanted bilaterally in the lateral ventricles. Animals received infusions of nerve growth factor (NGF), neurotrophin 3 (NT3), a combination of NGF and NT3, or a saline control over a 4-week period. Compared to saline-treated controls, animals sustaining saporin-induced damage to BFCNs took significantly more trials to learn a delayed match to position task and also performed more poorly on subsequent tests, with increasing delays between test runs. In contrast, animals infused with neurotrophins after saporin treatment performed significantly better than animals receiving saline infusions; no differences were detected for performance scores among animals infused with NGF, NT3, or a combination of NGF and NT3. Studies of ChAT immunnocytochemical labeling of BFCNs revealed a reduction in the numbers of ChAT-positive neurons in septum, nucleus of diagonal band, and nucleus basalis in animals treated with saporin followed by saline infusions, whereas animals treated with infusions of NGF, NT3 or a combination of NGF and NT3 showed only modest reductions in ChAT-positive neurons. Together, these data support the notion that administration of neurotrophic factors can rescue basal forebrain cholinergic neurons and improve learning and memory performance in rats.
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Affiliation(s)
- Yu-Shang Lee
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA, USA; Physical Medicine and Rehabilitation, School of Medicine, University of California, Irvine, CA, USA; Department of Neuroscience, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.
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Greig NH, Reale M, Tata AM. New pharmacological approaches to the cholinergic system: an overview on muscarinic receptor ligands and cholinesterase inhibitors. RECENT PATENTS ON CNS DRUG DISCOVERY 2013; 8:123-41. [PMID: 23597304 PMCID: PMC5831731 DOI: 10.2174/1574889811308020003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 04/13/2013] [Accepted: 04/13/2013] [Indexed: 12/27/2022]
Abstract
The cholinergic system is expressed in neuronal and in non-neuronal tissues. Acetylcholine (ACh), synthesized in and out of the nervous system can locally contribute to modulation of various cell functions (e.g. survival, proliferation). Considering that the cholinergic system and its functions are impaired in a number of disorders, the identification of new pharmacological approaches to regulate cholinergic system components appears of great relevance. The present review focuses on recent pharmacological drugs able to modulate the activity of cholinergic receptors and thereby, cholinergic function, with an emphasis on the muscarinic receptor subtype, and additionally covers the cholinesterases, the main enzymes involved in ACh hydrolysis. The presence and function of muscarinic receptor subtypes both in neuronal and non-neuronal cells has been demonstrated using extensive pharmacological data emerging from studies on transgenic mice. The possible involvement of ACh in different pathologies has been proposed in recent years and is becoming an important area of study. Although the lack of selective muscarinic receptor ligands has for a long time limited the definition of therapeutic treatment based on muscarinic receptors as targets, some muscarinic ligands such as cevimeline (patents US4855290; US5571918) or xanomeline (patent, US5980933) have been developed and used in pre-clinical or in clinical studies for the treatment of nervous system diseases (Alzheimer' and Sjogren's diseases). The present review focuses on the potential implications of muscarinic receptors in different pathologies, including tumors. Moreover, the future use of muscarinic ligands in therapeutic protocols in cancer therapy will be discussed, considering that some muscarinic antagonists currently used in the treatment of genitourinary disease (e.g. darifenacin, patent, US5096890; US6106864) have also been demonstrated to arrest tumor progression in nude mice. The involvement of muscarinic receptors in nociception also is over-viewed. In fact, muscarinic agonists such as vedaclidine, CMI-936 and CMI-1145 have been demonstrated to have analgesic effects in animal models comparable or more pronounced to those produced by morphine or opiates. Likewise, the crucial role of cholinesterases (acetylcholinesterase and butirylcholinesterase) in neural transmission is discussed, as large number of drugs inhibiting cholinesterase activity have become of increasing relevance particularly for the treatment of neurodegenerative disorders. Herein we summarize the current knowledge of the cholinesterase inhibitors with particular attention to recent patents for Alzheimer's disease drugs.
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Affiliation(s)
- Nigel H. Greig
- Drug Design and Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, Baltimore, MD, USA
| | - Marcella Reale
- Department of Experimental and Clinical Sciences, University G. D'Annunzio, Chieti, Italy
| | - Ada Maria Tata
- Dept. of Biology and Biotechnologies Charles Darwin, Sapienza Università di Roma, Research Center of Neurobiology Daniel Bovet, Roma, Italy
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Smith YR, Bowen L, Love TM, Berent-Spillson A, Frey KA, Persad CC, Reame NK, Koeppe RA, Zubieta JK. Early initiation of hormone therapy in menopausal women is associated with increased hippocampal and posterior cingulate cholinergic activity. J Clin Endocrinol Metab 2011; 96:E1761-70. [PMID: 21865354 PMCID: PMC3205894 DOI: 10.1210/jc.2011-0351] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
CONTEXT The role of ovarian hormones in maintaining neuronal integrity and cognitive function is still debated. This study was undertaken to clarify the potential relationship between postmenopausal hormone use and the cholinergic system. OBJECTIVE We hypothesized that early initiated hormone therapy (HT) preserves the cholinergic system and that estrogen therapy (ET) would be associated with higher levels of acetylcholinesterase activity in the posterior cingulate cortex and hippocampus compared to estrogen plus progestin therapy (EPT) or no HT. DESIGN AND SETTING We conducted a cross-sectional study at a university teaching hospital. PATIENTS Fifty postmenopausal women (age, 65.2 ± 0.7 yr) with early long-term HT (n = 34; 13 ET and 21 EPT) or no HT (n = 16) participated in the study. INTERVENTIONS There were no interventions. MAIN OUTCOME MEASURE We measured cholinergic activity (acetylcholinesterase) in the hippocampus and posterior cingulate brain regions as measured by N-[(11)C]methylpiperidin-4-yl propionate and positron emission tomography as a marker of cholinergic function. RESULTS Significant effects of treatment on cholinergic activity measures were obtained in the left hippocampus (F = 3.56; P = 0.04), right hippocampus (F = 3.42; P = 0.04), and posterior cingulate (F = 3.76; P = 0.03). No significant effects were observed in a cortical control region. Post hoc testing identified greater cholinergic activity in the EPT group compared to the no-HT group in the left hippocampus (P = 0.048) and posterior cingulate (P = 0.045), with a nonstatistically significant trend in the right hippocampus (P = 0.073). CONCLUSIONS A differential effect of postmenopausal ET and EPT on cholinergic neuronal integrity was identified in postmenopausal women. The findings are consistent with a preservation of cholinergic neuronal integrity in the EPT group.
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Affiliation(s)
- Yolanda R Smith
- Department of Obstetrics and Gynecology, University of Michigan Health Systems, 1500 East Medical Center Drive, Room L4224 Women's Hospital, Ann Arbor, Michigan 48109-0276, USA.
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Potter PE, Rauschkolb PK, Pandya Y, Sue LI, Sabbagh MN, Walker DG, Beach TG. Pre- and post-synaptic cortical cholinergic deficits are proportional to amyloid plaque presence and density at preclinical stages of Alzheimer's disease. Acta Neuropathol 2011; 122:49-60. [PMID: 21533854 DOI: 10.1007/s00401-011-0831-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 04/19/2011] [Accepted: 04/23/2011] [Indexed: 12/23/2022]
Abstract
Amyloid imaging has identified cognitively normal older people with plaques as a group possibly at increased risk for developing Alzheimer's disease-related dementia. It is important to begin to thoroughly characterize this group so that preventative therapies might be tested. Existing cholinotropic agents are a logical choice for preventative therapy as experimental evidence suggests that they are anti-amyloidogenic and clinical trials have shown that they delay progression of mild cognitive impairment to dementia. A detailed understanding of the status of the cortical cholinergic system in preclinical AD is still lacking, however. For more than 30 years, depletion of the cortical cholinergic system has been known to be one of the characteristic features of AD. Reports to date have suggested that some cholinergic markers are altered prior to cognitive impairment while others may show changes only at later stages of dementia. These studies have generally been limited by relatively small sample sizes, long postmortem intervals and insufficient definition of control and AD subjects by the defining histopathology. We, therefore, examined pre- and post-synaptic elements of the cortical cholinergic system in frontal and parietal cortex in 87 deceased subjects, including non-demented elderly with and without amyloid plaques as well as demented persons with neuropathologically confirmed AD. Choline acetyltransferase (ChAT) activity was used as a presynaptic marker while displacement of (3)H-pirenzepine binding by oxotremorine-M in the presence and absence of GppNHp was used to assess postsynaptic M1 receptor coupling. The results indicate that cortical ChAT activity as well as M1 receptor coupling are both significantly decreased in non-demented elderly subjects with amyloid plaques and are more pronounced in subjects with AD and dementia. These findings confirm that cortical cholinergic dysfunction in AD begins at the preclinical stage of disease and suggest that cholinotropic agents currently used for AD treatment are a logical choice for preventative therapy.
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Affiliation(s)
- Pamela E Potter
- Department of Pharmacology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ 85308, USA.
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Papandreou MA, Tsachaki M, Efthimiopoulos S, Cordopatis P, Lamari FN, Margarity M. Memory enhancing effects of saffron in aged mice are correlated with antioxidant protection. Behav Brain Res 2011; 219:197-204. [DOI: 10.1016/j.bbr.2011.01.007] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 12/31/2010] [Accepted: 01/07/2011] [Indexed: 10/18/2022]
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Craig LA, Hong NS, McDonald RJ. Revisiting the cholinergic hypothesis in the development of Alzheimer's disease. Neurosci Biobehav Rev 2011; 35:1397-409. [PMID: 21392524 DOI: 10.1016/j.neubiorev.2011.03.001] [Citation(s) in RCA: 301] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 02/25/2011] [Accepted: 03/01/2011] [Indexed: 12/21/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia affecting the elderly population today; however, there is currently no accurate description of the etiology of this devastating disorder. No single factor has been demonstrated as being causative; however, an alternative co-factors theory suggests that the interaction of multiple risk factors is responsible for AD. We have used this model, in combination with the original cholinergic hypothesis of AD to propose a "new" cholinergic hypothesis that we present in this review. This new version takes into account recent findings from the literature and our reports of removal of medial septum cholinergic projections to the hippocampus reduces both behavioural and anatomical plasticity, resulting in greater cognitive impairment in response to secondary insults (stress, injury, disease, etc.). We will first summarize the experimental results and discuss some potential mechanisms that could explain our results. We will then present our 'new' version of the cholinergic hypothesis and how it relates to the field of AD research today. Finally we will discuss some of the implications for treatment that arise from this model and present directions for future study.
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Affiliation(s)
- Laura A Craig
- Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge; 4401 University Drive, Lethbridge, AB, Canada
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Amadoruge PC, Barnham KJ. Alzheimer's disease and metals: a review of the involvement of cellular membrane receptors in metallosignalling. Int J Alzheimers Dis 2011; 2011:542043. [PMID: 21461392 PMCID: PMC3065006 DOI: 10.4061/2011/542043] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 01/05/2011] [Indexed: 01/12/2023] Open
Abstract
Alzheimer's disease (AD) is a debilitating form of dementia. The hallmark protein associated with the disease is the amyloid beta (Aβ) peptide. Aggregation of Aβ has been shown to depend on interactions with metals. The recent studies now demonstrate that metals also play additional important roles in the disease process. Consequently, there may be benefit from modulating metal homeostasis. However, the role and subcellular location of metals within neurons is not well understood. There is growing evidence to suggest that metals can act at the site of cellular membrane receptors and affect cellular signaling by modulating the signal transduction of those receptors. The glutamatergic and cholinergic receptor systems, both well-known neurotransmitter systems affected in AD, have well-documented metal interactions, as do the tropomyosin-receptor kinase (Trk) family of receptors and the epidermal growth factor (EGF) receptor. In this paper, the metal interactions with these membrane receptor systems will be explored and thus the potential for membrane receptors as an intervention point in AD will be assessed.
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Affiliation(s)
- Pavithra C Amadoruge
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, VIC 3010, Australia
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28
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Pepeu G, Giovannini MG. Cholinesterase inhibitors and memory. Chem Biol Interact 2010; 187:403-8. [DOI: 10.1016/j.cbi.2009.11.018] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 11/17/2009] [Accepted: 11/18/2009] [Indexed: 12/26/2022]
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Sabbagh MN, Farlow MR, Relkin N, Beach TG. Do cholinergic therapies have disease-modifying effects in Alzheimer's disease? Alzheimers Dement 2009; 2:118-25. [PMID: 19595868 DOI: 10.1016/j.jalz.2006.02.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Accepted: 02/08/2006] [Indexed: 10/24/2022]
Abstract
The most widely studied and used therapies for Alzheimer's disease (AD) are based on improving cholinergic function in the central nervous system. The acetylcholine-esterase inhibitors (ChEIs) tacrine, donepezil, rivastigmine, and galantamine are all approved, and the latter three are widely used for the symptomatic treatment of mild to moderate AD. Recent research has found that these drugs may act by a variety of other mechanisms including inhibition of butylcholinesterase, regulation of nicotinic receptors, decreasing amyloid precursor protein (APP) and A beta production, and regulation of tau phosphorylation that may influence disease progression. There is also emerging evidence from clinical trials that the ChEIs may delay cognitive and functional progression. Other cholinergic drugs such as muscarinic agonists have been explored, and although they are not approved, there is robust preclinical evidence for a beneficial, perhaps disease-modifying effect. This review summarizes evidence suggesting that these drugs may do more than improve symptoms; they may delay biological progression of the disease.
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Affiliation(s)
- Marwan N Sabbagh
- Cleo Roberts Center for Clinical Research, Sun Health Research Institute, Sun City, AZ, USA.
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30
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Ellis J, Nathan P, Villemagne V, Mulligan R, Ellis K, Tochon-Danguy H, Chan J, O'keefe G, Bradley J, Savage G, Rowe C. The relationship between nicotinic receptors and cognitive functioning in healthy aging: An in vivo positron emission tomography (PET) study with 2-[18F]fluoro-A-85380. Synapse 2009; 63:752-63. [DOI: 10.1002/syn.20642] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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31
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Niewiadomska G, Baksalerska-Pazera M, Riedel G. The septo-hippocampal system, learning and recovery of function. Prog Neuropsychopharmacol Biol Psychiatry 2009; 33:791-805. [PMID: 19389457 DOI: 10.1016/j.pnpbp.2009.03.039] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2009] [Accepted: 03/30/2009] [Indexed: 12/23/2022]
Abstract
We understand this review as an attempt to summarize recent advances in the understanding of cholinergic function in cognition. Such a role has been highlighted in the 1970s by the discovery that dementia patients have greatly reduced cholinergic activity in cortex and hippocampus. A brief anatomical description of the major cholinergic pathways focuses on the basal forebrain and its projections to cortex and hippocampus. From this distinction, compelling evidence suggests that the basal forebrain --> cortex projection regulates the excitability of principal cortical neurons and is thereby critically involved in attention, stimulus detection and memory function, although the biological conditions for these functions are still debated. Similar uncertainties remain for the septo-hippocampal cholinergic system. Although initial lesions of the septum caused memory deficits reminiscent of hippocampal ablations, recent and more refined neurotoxic lesion studies which spared non-cholinergic cells of the basal forebrain failed to confirm these memory impairments in experimental animals despite a near total loss of cholinergic labeling. Yet, a decline in cholinergic markers in aging and dementia still stands as the most central piece of evidence for a link between the cholinergic system and cognition and appear to provide valuable targets for therapeutic approaches.
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Abstract
BACKGROUND Research in Alzheimer's disease is focused mainly on younger old persons, whereas studies involving very old persons report attenuated relationships between the pathological features of Alzheimer's disease and dementia. METHODS We assessed 456 brains donated to the population-based Medical Research Council Cognitive Function and Ageing Study from persons 69 to 103 years of age at death. We used a standard neuropathological protocol that included measures of the pathological features of Alzheimer's disease, cerebral atrophy, and cerebrovascular disease. Neuropathological variables were dichotomized to represent no burden or a mild burden of pathological lesions as compared with a moderate or severe burden. Logistic regression was used to estimate the effect of age on the relationship between neuropathological features and dementia. RESULTS The difference in the prevalence of moderate and severe Alzheimer's-type pathological changes between persons with and those without dementia decreased with increasing age. The association between neocortical neuritic plaques and dementia was strong at 75 years of age (odds ratio, 8.63; 95% confidence interval [CI], 3.81 to 19.60) and reduced at 95 years of age (odds ratio, 2.48; 95% CI, 0.92 to 4.14), and similar attenuations with advancing age were observed in the association between other pathological changes related to Alzheimer's disease and dementia in all brain areas. In contrast, neocortical cerebral atrophy maintained a relationship with age in persons with dementia at both 75 years of age (odds ratio, 5.11; 95% CI, 1.94 to 13.46) and 95 years of age (odds ratio, 6.10; 95% CI, 2.80 to 13.28) and thus distinguished the cohort with dementia from the cohort without dementia. CONCLUSIONS The association between the pathological features of Alzheimer's disease and dementia is stronger in younger old persons than in older old persons. Age must be taken into account when assessing the likely effect of interventions against dementia on the population.
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Affiliation(s)
- George M Savva
- Department of Public Health and Primary Care, Institute of Public Health, University of Cambridge, Cambridge, United Kingdom
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33
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Craig LA, Hong NS, Kopp J, McDonald RJ. Reduced cholinergic status in hippocampus produces spatial memory deficits when combined with kainic acid induced seizures. Hippocampus 2008; 18:1112-21. [DOI: 10.1002/hipo.20471] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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34
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Selective lesion of medial septal cholinergic neurons followed by a mini-stroke impairs spatial learning in rats. Exp Brain Res 2008; 193:29-42. [DOI: 10.1007/s00221-008-1592-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Accepted: 09/23/2008] [Indexed: 01/25/2023]
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Bennett KM, Hoelting C, Martin CP, Stoll J. Estrogen effects on high-affinity choline uptake in primary cultures of rat basal forebrain. Neurochem Res 2008; 34:205-14. [PMID: 18483854 DOI: 10.1007/s11064-008-9746-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Accepted: 05/07/2008] [Indexed: 10/22/2022]
Abstract
Basal forebrain cholinergic neurons (BFCNs) degenerate in aging and Alzheimer's disease. It has been proposed that estrogen can affect the survival and function of BFCNs. This study characterized primary rat BFCN cultures and investigated the effect of estrogen on high-affinity choline uptake (HACU). BFCNs were identified by immunoreactivity to the vesicular acetylcholine transporter (VAChT) and represented up to 5% of total cells. HACU was measured in living BFCN cultures and differentiated from low-affinity choline uptake by hemicholinium-3 (HC-3) inhibition. A HC-3 concentration curve showed that 0.3 muM HC-3, but not higher concentrations that inhibit LACU, could distinguish the two transport activities. 17-beta-Estradiol treatment increased HACU in some culture preparations that contained non-neuronal cells. Elimination of dividing cells using antimitotic treatments resulted in a lack of estrogen effects on HACU. These results suggest that estrogen may have indirect effects on BFCNs that are mediated through non-neuronal cells.
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Affiliation(s)
- Katie M Bennett
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, School of Pharmacy, 1300 S Coulter, Amarillo, TX 79106, USA
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36
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Schindowski K, Belarbi K, Buée L. Neurotrophic factors in Alzheimer's disease: role of axonal transport. GENES BRAIN AND BEHAVIOR 2008; 7 Suppl 1:43-56. [PMID: 18184369 PMCID: PMC2228393 DOI: 10.1111/j.1601-183x.2007.00378.x] [Citation(s) in RCA: 232] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Neurotrophic factors (NTF) are small, versatile proteins that maintain survival and function to specific neuronal populations. In general, the axonal transport of NTF is important as not all of them are synthesized at the site of its action. Nerve growth factor (NGF), for instance, is produced in the neocortex and the hippocampus and then retrogradely transported to the cholinergic neurons of the basal forebrain. Neurodegenerative dementias like Alzheimer’s disease (AD) are linked to deficits in axonal transport. Furthermore, they are also associated with imbalanced distribution and dysregulation of NTF. In particular, brain-derived neurotrophic factor (BDNF) plays a crucial role in cognition, learning and memory formation by modulating synaptic plasticity and is, therefore, a critical molecule in dementia and neurodegenerative diseases. Here, we review the changes of NTF expression and distribution (NGF, BDNF, neurotrophin-3, neurotrophin-4/5 and fibroblast growth factor-2) and their receptors [tropomyosin-related kinase (Trk)A, TrkB, TrkC and p75NTR] in AD and AD models. In addition, we focus on the interaction with neuropathological hallmarks Tau/neurofibrillary tangle and amyloid-β (Abeta)/amyloid plaque pathology and their influence on axonal transport processes in order to unify AD-specific cholinergic degeneration and Tau and Abeta misfolding through NTF pathophysiology.
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Affiliation(s)
- K Schindowski
- Institut National de la Santé et de la Research Médicale U837, Université Lille 2, Lille Cedex, France.
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37
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Abstract
BACKGROUND In consultation-liaison settings, neuropsychiatrists are commonly asked to assess patients with hallucinatory syndromes and to differentiate 'functional' from 'organic' psychotic presentations. METHODS The occurrence and management of visual hallucinations (VH) in healthy individuals, lesion states, neurodegenerative disorders, intoxication/withdrawal states and delirium are reviewed. RESULTS The presence of VH has been shown to predict a secondary rather than primary psychotic illness and an understanding of the neurobiology of the visual system - including how and where underlying neurotransmitter systems interact in visual processing and how perturbations can result in VH - allows for appropriate clinical assessment and management.
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Affiliation(s)
- Mark Walterfang
- 1Melbourne Neuropsychiatry Centre, University of Melbourne, Parkville, Victoria, Australia
| | - Ramon Mocellin
- 1Melbourne Neuropsychiatry Centre, University of Melbourne, Parkville, Victoria, Australia
| | - Dennis Velakoulis
- 1Melbourne Neuropsychiatry Centre, University of Melbourne, Parkville, Victoria, Australia
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Liang WS, Dunckley T, Beach TG, Grover A, Mastroeni D, Walker DG, Caselli RJ, Kukull WA, McKeel D, Morris JC, Hulette C, Schmechel D, Alexander GE, Reiman EM, Rogers J, Stephan DA. Gene expression profiles in anatomically and functionally distinct regions of the normal aged human brain. Physiol Genomics 2006; 28:311-22. [PMID: 17077275 PMCID: PMC2259385 DOI: 10.1152/physiolgenomics.00208.2006] [Citation(s) in RCA: 213] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this article, we have characterized and compared gene expression profiles from laser capture microdissected neurons in six functionally and anatomically distinct regions from clinically and histopathologically normal aged human brains. These regions, which are also known to be differentially vulnerable to the histopathological and metabolic features of Alzheimer's disease (AD), include the entorhinal cortex and hippocampus (limbic and paralimbic areas vulnerable to early neurofibrillary tangle pathology in AD), posterior cingulate cortex (a paralimbic area vulnerable to early metabolic abnormalities in AD), temporal and prefrontal cortex (unimodal and heteromodal sensory association areas vulnerable to early neuritic plaque pathology in AD), and primary visual cortex (a primary sensory area relatively spared in early AD). These neuronal profiles will provide valuable reference information for future studies of the brain, in normal aging, AD and other neurological and psychiatric disorders.
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Affiliation(s)
- Winnie S Liang
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, AZ 85004, USA
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Wilson IA, Gallagher M, Eichenbaum H, Tanila H. Neurocognitive aging: prior memories hinder new hippocampal encoding. Trends Neurosci 2006; 29:662-70. [PMID: 17046075 PMCID: PMC2614702 DOI: 10.1016/j.tins.2006.10.002] [Citation(s) in RCA: 235] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Revised: 07/26/2006] [Accepted: 10/04/2006] [Indexed: 02/07/2023]
Abstract
Normal aging is often accompanied by impairments in forming new memories, and studies of aging rodents have revealed structural and functional changes to the hippocampus that might point to the mechanisms behind such memory loss. In this article, we synthesize recent neurobiological and neurophysiological findings into a model of the information-processing circuit of the aging hippocampus. The key point of the model is that small concurrent changes during aging strengthen the auto-associative network of the CA3 subregion at the cost of processing new information coming in from the entorhinal cortex. As a result of such reorganization in aged memory-impaired individuals, information that is already stored would become the dominant pattern of the hippocampus to the detriment of the ability to encode new information.
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Affiliation(s)
- Iain A Wilson
- Department of Neuroscience and Neurology, University of Kuopio, Kuopio 70211, Finland.
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Borchelt DR, Wong PC, Sisodia SS, Price DL. Transgenic mouse models of Alzheimer's disease and amyotrophic lateral sclerosis. Brain Pathol 2006; 8:735-57. [PMID: 9804381 PMCID: PMC8098285 DOI: 10.1111/j.1750-3639.1998.tb00198.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Over the past several years, there has been enormous progress in generating transgenic mice that model aspects of human neurodegenerative diseases. These studies build upon the efforts of molecular geneticists who have identified a number of genes that, when mutated, cause familial forms of these diseases. In this review, we focus on the mutations that cause familial forms of Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS), and transgenic mouse models that develop clinical and pathological abnormalities resembling those occurring in the human diseases.
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Affiliation(s)
- D R Borchelt
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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Zhang HY, Watson ML, Gallagher M, Nicolle MM. Muscarinic receptor-mediated GTP-Eu binding in the hippocampus and prefrontal cortex is correlated with spatial memory impairment in aged rats. Neurobiol Aging 2006; 28:619-26. [PMID: 16600436 DOI: 10.1016/j.neurobiolaging.2006.02.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 02/23/2006] [Accepted: 02/28/2006] [Indexed: 10/24/2022]
Abstract
The present study examined muscarinic receptor/G-protein coupling in the hippocampus and the prefrontal cortex of young and aged Long-Evans rats characterized for spatial learning ability in the Morris water maze. In a highly sensitive time-resolved fluorometry GTP-Eu binding assay, muscarinic-mediated GTP-Eu binding was severely blunted in hippocampus (-32%) and prefrontal cortex (-34%) as a consequence of aging. Furthermore, the magnitude of decreased muscarinic-mediated GTP-Eu binding was significantly correlated with the severity of spatial learning impairment in hippocampus and prefrontal cortex of aged rats and was specifically decreased in the subset of aged rats that were spatial learning impaired when compared to the aged unimpaired and the young rats. Western blot data indicated a preservation of the membrane-bound M1 receptor and the Galphaq/11 protein in both brain regions. These data demonstrate that muscarinic signaling is severely impaired as a consequence of normal aging in a manner that is closely associated with age-related cognitive decline.
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Affiliation(s)
- Hai-Yan Zhang
- Roena Kulynych Center for Memory and Cognition Research, Department of Internal Medicine/Gerontology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1083, USA
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Sahin HA, Emre M, Ziabreva I, Perry E, Celasun B, Perry R. The distribution pattern of pathology and cholinergic deficits in amygdaloid complex in Alzheimer's disease and dementia with Lewy bodies. Acta Neuropathol 2006; 111:115-25. [PMID: 16468020 DOI: 10.1007/s00401-005-0003-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Revised: 09/23/2005] [Accepted: 09/23/2005] [Indexed: 11/28/2022]
Abstract
We studied the distribution pattern of pathology and cholinergic deficits in the subnuclei of the amygdaloid complex (AC) in five patients with Alzheimer's disease (AD), eight with dementia with Lewy bodies (DLB) and five normal controls. In controls, the basal nucleus contained the highest choline acetyltransferase activity; the activity in the lateral and central nuclei and those in the cortical, medial and accessory basal nuclei were comparable. In AD, there was a significant decrease in choline acetyltransferase activity in the accessory basal and lateral nuclei, in DLB a significant decrease was observed in the accessory basal, lateral and cortical nuclei. Compared to controls the hyperphosphorylated tau-pathology burden was significantly higher in the basal, central and medial nuclei in AD and in the central, cortical, lateral and medial nuclei in DLB. The amyloid plaque burden was significantly higher in the accessory basal, basal, lateral and cortical nuclei in AD and in all nuclei in DLB. The alpha-synuclein burden was significantly higher in all nuclei in both AD and DLB. Compared to AD alpha-synuclein burden was higher in all nuclei in DLB. There were no correlations between the distribution pattern of hyperphosphorylated tau-pathology, amyloid plaques and alpha-synuclein-positive structures, and choline acetyltransferase activity, except the lateral nucleus in DLB. In conclusion we found no relationship between the pattern of cholinergic deficits and the distribution pattern of lesions in the AC of patients with AD or DLB. Cholinergic deficits were more prominent in the nuclei of basolateral (BL) group in AD, whereas the nuclei of both BL and corticomedial groups were involved in DLB, which may be due to the involvement of both basal forebrain and brainstem cholinergic nuclei in the latter.
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Affiliation(s)
- Huseyin A Sahin
- Department of Neurology, Ondokuz Mayis University, Faculty of Medicine, Kurupelit, 55139, Samsun, Turkey.
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Bosboom JLW, Wolters EC. Psychotic symptoms in Parkinson’s disease: pathophysiology and management. Expert Opin Drug Saf 2005. [DOI: 10.1517/14740338.3.3.209] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Van Dam D, Marescau B, Engelborghs S, Cremers T, Mulder J, Staufenbiel M, De Deyn PP. Analysis of cholinergic markers, biogenic amines, and amino acids in the CNS of two APP overexpression mouse models. Neurochem Int 2005; 46:409-22. [PMID: 15737439 DOI: 10.1016/j.neuint.2004.11.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2004] [Revised: 11/17/2004] [Accepted: 11/18/2004] [Indexed: 10/25/2022]
Abstract
Two transgenic mouse models expressing mutated human amyloid precursor protein and previously found to display cognitive and behavioural alterations, reminiscent of Alzheimer patients' symptomatology, were scrutinised for putative brain region-specific changes in neurochemical parameters. Brains of NSE-hAPP751m-57, APP23 and wild-type mice were microdissected to perform brain region-specific neurochemical analyses. Impairment of cholinergic transmission, the prominent neurochemical deficit in Alzheimer brain, was examined; acetylcholinesterase and choline acetyltransferase activity levels were determined as markers of the cholinergic system. Since Alzheimer neurodegeneration is not restricted to the cholinergic system, brain levels of biogenic amines and metabolites, and amino acidergic neurotransmitters and systemic amino acids were analysed as well. Cholinergic dysfunction, reflected in reduced enzymatic activity in the basal forebrain nuclei, was restricted to the APP23 model, which also exhibited more outspoken and more widespread changes in other neurotransmitter systems. Significant changes in compounds of the noradrenergic and serotonergic system were observed, as well as alterations in levels of the inhibitory neurotransmitter glycine and systemic amino acids. These observations were clearly in occurrence with the more pronounced histopathological and behavioural phenotype of the APP23 model. As transgenic models often do not represent an end-stage of the disease, some discrepancies with results from post-mortem human Alzheimer brain analyses were apparent; in particular, no significant alterations in excitatory amino acid levels were detected. Our findings of brain region-specific alterations in compound levels indicate disturbed neurotransmission pathways, and greatly add to the validity of APP23 mice as a model for Alzheimer's disease. Transgenic mouse models may be employed as a tool to study early-stage neurochemical changes, which are often not accessible in Alzheimer brain.
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Affiliation(s)
- Debby Van Dam
- Laboratory of Neurochemistry and Behaviour, Born-Bunge Institute, Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium
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Corcoran JPT, So PL, Maden M. Disruption of the retinoid signalling pathway causes a deposition of amyloid beta in the adult rat brain. Eur J Neurosci 2004; 20:896-902. [PMID: 15305858 DOI: 10.1111/j.1460-9568.2004.03563.x] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have disrupted the retinoid signalling pathway in adult rats by a dietary deficiency of vitamin A. After 1 year of this dietary deficiency, there was a deposition of amyloid beta in the cerebral blood vessels. There is a downregulation of retinoic acid receptor alpha in the forebrain neurons of the retinoid-deficient rats and a loss of choline acetyl transferase expression, which precedes amyloid beta deposition. In neocortex of pathology samples of patients with Alzheimer's disease, the same retinoic acid receptor alpha deficit in the surviving neurons was observed. We have identified the retinoid-synthesizing enzymes involved in this process, retinaldehyde dehydrogenase-2 and class IV alcohol dehydrogenase, only the former is downregulated in patients with Alzheimer's disease. This suggests that retinoids are important for the maintenance of the adult nervous system and their loss may in part play a role in Alzheimer's disease.
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Affiliation(s)
- Jonathan P T Corcoran
- MRC Centre for Developmental Neurobiology, New Hunt's House, King's College London, Guy's Campus, London SE1 1UL, UK.
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Laplante F, Sibley DR, Quirion R. Reduction in acetylcholine release in the hippocampus of dopamine D5 receptor-deficient mice. Neuropsychopharmacology 2004; 29:1620-7. [PMID: 15100705 DOI: 10.1038/sj.npp.1300467] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Activation of the dopamine D1-like receptor stimulates acetylcholine (ACh) release in the hippocampus, apparently through the molecularly defined d5 receptor. In the present study, we used a transgenic mouse completely deprived of functional d5 receptor (d5-/-) to confirm the role and elucidate the possible function of the d5 receptor subtype on hippocampal cholinergic neurotransmission. ACh release was measured using in vivo microdialysis in the mouse dorsal hippocampus of 4 months old homozygous (d5-/-), heterozygous (d5+/-), and the wild-type (d5+/+) littermates. Using the no net flux technique, a significant reduction in basal hippocampal ACh level was found in the d5-/- compared to d5+/- and d5+/+ mice. Moreover, the administration of SKF 38393, a D1-like receptor agonist, systemically (2.0 and 10.0 mg/kg ip), or locally through the dialysis probe (10 and 50 microM), produced a dose-dependent enhancement of ACh release in the d5+/+, a moderate stimulation in the d5+/- but had no effect in the d5-/- mice. Quantitative receptor autoradiography revealed significant increases in M1-like but not in M2-like muscarinic receptor binding sites in the hippocampal formation. These results confirm and extend the role of the d5 receptor in the modulation of hippocampal ACh release and provide evidence for long-term alteration of hippocampal cholinergic neurotransmission resulting from the absence of the d5 receptors including chronically reduced ACh release and change in M1-like receptor levels.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Acetylcholine/metabolism
- Animals
- Autoradiography
- Dopamine Agonists/pharmacology
- Extracellular Space/metabolism
- Hippocampus/anatomy & histology
- Hippocampus/drug effects
- Hippocampus/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microdialysis
- Receptor, Muscarinic M1/metabolism
- Receptors, Dopamine D1/drug effects
- Receptors, Dopamine D1/genetics
- Receptors, Dopamine D1/physiology
- Receptors, Dopamine D5
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Garcia-Alloza M, Hirst WD, Chen CPLH, Lasheras B, Francis PT, Ramírez MJ. Differential involvement of 5-HT(1B/1D) and 5-HT6 receptors in cognitive and non-cognitive symptoms in Alzheimer's disease. Neuropsychopharmacology 2004; 29:410-6. [PMID: 14571255 DOI: 10.1038/sj.npp.1300330] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Growing evidence suggests that a compromised serotonergic system plays an important role in the pathophysiology of Alzheimer's disease (AD). We assessed the expression of 5-HT(1B/1D) and 5-HT(6) receptors and cholinacetyltransferase (ChAT) activity in post-mortem frontal and temporal cortex from AD patients who had been prospectively assessed for cognitive function using the Mini-Mental State Examination (MMSE) and behavioral changes using the Present Behavioral Examination (PBE). 5-HT(1B/1D) and 5-HT(6) receptor densities were significantly reduced in both cortical areas. 5-HT(1B/1D) receptor density was correlated to MMSE decline in the frontal cortex, supporting its implication in memory impairment. The best predictor for lowered 5-HT(6) receptor density in the temporal cortex was the PBE measure of overactivity. The 5-HT(6)/ChAT ratio was related to aggression both in the frontal and temporal cortex. Therefore, antagonists acting at 5-HT(6) receptors could be useful in the treatment of non-cognitive symptoms associated to AD.
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Affiliation(s)
- M Garcia-Alloza
- Department of Pharmacology, School of Medicine, University of Navarra, Pamplona, Spain
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Foley AG, Murphy KJ, Hirst WD, Gallagher HC, Hagan JJ, Upton N, Walsh FS, Regan CM. The 5-HT(6) receptor antagonist SB-271046 reverses scopolamine-disrupted consolidation of a passive avoidance task and ameliorates spatial task deficits in aged rats. Neuropsychopharmacology 2004; 29:93-100. [PMID: 14571256 DOI: 10.1038/sj.npp.1300332] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The highly potent and selective 5-HT(6) receptor antagonist SB-271046 [5-chloro-N-(4-methoxy-3-piperazin-1-yl-phenyl)-3-methyl-2-benzothiophenesulfonamide] has previously been demonstrated to improve retention significantly in a spatial water maze paradigm in adult rats. However, SB-271046 did not have any effect on task acquisition. As these apparently contradictory findings may be reconciled by a prime influence of SB-271046 on memory consolidation, the ability of this compound to reverse the discrete temporal action of a cholinergic antagonist in the 6-h period following passive avoidance training was investigated. SB-271046, given orally, by gavage, 30 min prior to training Wistar rats in a step-through, light-dark passive avoidance task, was found to reverse significantly the amnesia produced by administering scopolamine (0.8 mg/kg, intraperitoneal) in the 6-h post-training period. The effect was dose-dependent over a range of 3-20 mg/kg. Further, we investigated the cognition-enhancing effects of chronic SB-271046 administration (10 or 20 mg/kg/day; 40 days) on the acquisition and consolidation of a water maze spatial learning task in a population of 20-month-old Wistar rats with age-related learning deficits. Drug treatment progressively and significantly decreased platform swim angle and escape latencies over the five sequential trials on four consecutive daily sessions compared to vehicle-treated controls. SB-271046 also improved task recall as measured by significant increases in the searching of the target quadrant on post-training days 1 and 3, when the animals would have been substantially drug-free. This significant improvement of task recall suggests SB-271046, in addition to inducing symptomatic cognition-enhancing actions, also attenuates age-related decline in neural function.
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Affiliation(s)
- Andrew G Foley
- Department of Pharmacology, Conway Institute, University College Dublin, Belfield, Ireland
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Hu L, Wong TP, Côté SL, Bell KFS, Cuello AC. The impact of Aβ-plaques on cortical cholinergic and non-cholinergic presynaptic boutons in alzheimer's disease-like transgenic mice. Neuroscience 2003; 121:421-32. [PMID: 14522000 DOI: 10.1016/s0306-4522(03)00394-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A previous study in our laboratory, involving early stage, amyloid pathology in 8-month-old transgenic mice, demonstrated a selective loss of cholinergic terminals in the cerebral and hippocampal cortices of doubly transgenic (APP(K670N,M671L)+PSl(M146L)) mice, an up-regulation in the single mutant APP(K670N,M671L) mice and no detectable change in the PSl(M146L) transgenics [J Neurosci 19 (1999) 2706]. The present study investigates the impact of amyloid plaques on synaptophysin and vesicular acetylcholine transporter (VAChT) immunoreactive bouton numbers in the frontal cortex of the three transgenic mouse models previously described. When compared as a whole, the frontal cortices of transgenic and control mice show no observable differences in the densities of synaptophysin-immunoreactive boutons. An individual comparison of layer V of the frontal cortex, however, shows a significant increase in density in transgenic models. Analysis of the cholinergic system alone shows significant alterations in the VAChT-immunoreactive bouton densities as evidenced by an increased density in the single (APP(K670N,M671L)) transgenics and a decreased density in the doubly transgenics (APP(K670N,M671L)+PSl(M146L)). In investigating the impact of plaque proximity on bouton density at early stages of the amyloid pathology in our doubly (APP(K670N,M671L)+PSl(M146L)) transgenic mouse line, we observed that plaque proximity reduced cholinergic pre-synaptic bouton density by 40%, and yet increased synaptophysin-immunoreactive pre-synaptic bouton density by 9.5%. Distance from plaques (up to 60 microm) seemed to have no effect on bouton density; however a significant inverse relationship was visible between plaque size and cholinergic pre-synaptic bouton density. Finally, the number of cholinergic dystrophic neurites surrounding the truly amyloid, Thioflavin-S(+) plaque core, was disproportionately large with respect to the incidence of cholinergic boutons within the total pre-synaptic bouton population. Confocal and electron microscopic observations confirmed the preferential infiltration of dystrophic cholinergic boutons into fibrillar amyloid aggregates. We therefore hypothesize that extracellular Abeta aggregation preferentially affects cholinergic terminations prior to progression onto other neurotransmitter systems. This is supported by the observable presence of non-cholinergic sprouting, which may be representative of impending neuritic degeneration.
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Affiliation(s)
- L Hu
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Quebec, Montreal, Canada H3G 1Y6
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