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Chauhan P, Wadhwa K, Singh G, Gupta S, Iqbal D, Abomughaid MM, Almutary AG, Mishra PC, Nelson VK, Jha NK. Exploring complexities of Alzheimer's disease: New insights into molecular and cellular mechanisms of neurodegeneration and targeted therapeutic interventions. Ageing Res Rev 2024:102548. [PMID: 39419399 DOI: 10.1016/j.arr.2024.102548] [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: 01/26/2024] [Revised: 10/09/2024] [Accepted: 10/11/2024] [Indexed: 10/19/2024]
Abstract
Alzheimer's disease (AD), the common form of dementia globally, is a complex condition including neurodegeneration; shares incompletely known pathogenesis. Signal transduction and biological activities, including cell metabolism, growth, and death are regulated by different signaling pathways including AKT/MAPK, Wnt, Leptin, mTOR, ubiquitin, Sirt1, and insulin. Absolute evidence linking specific molecular pathways with the genesis and/or progression of AD is still lacking. Changes in gut microbiota and blood-brain barrier also cause amyloid β aggregation in AD. The current review reports significant characteristics of various signaling pathways, their relationship with each other, and how they interact in disease genesis and/or progression. Nevertheless, due to the enormous complexity of the brain and numerous chemical linkages between these pathways, the use of signaling pathways as possible targets for drug development against AD is minimal. Currently, there is no permanent cure for AD, and there is no way to stop brain cell loss. This review also aimed to draw attention to the role of a novel group of signaling pathways, which can be collectively dubbed "anti-AD pathways", in multi-target therapy for AD, where cellular metabolic functions are severely impaired. Thus, different hypotheses have been formulated and elaborated to explain the genesis of AD, which can be further explored for drug development too.
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Affiliation(s)
- Payal Chauhan
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, Haryana, 124001, India
| | - Karan Wadhwa
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, Haryana, 124001, India
| | - Govind Singh
- Department of Pharmaceutical Sciences, Maharshi Dayanand University, Rohtak, Haryana, 124001, India.
| | - Saurabh Gupta
- Deparment of Biotechnology, GLA University, Mathura, India
| | - Danish Iqbal
- Department of Health Information Management, College of Applied Medical Sciences, Buraydah Private Colleges, Buraydah 51418, Saudi Arabia
| | - Mosleh Mohammad Abomughaid
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, University of Bisha, Bisha, 61922, Saudi Arabia
| | - Abdulmajeed G Almutary
- Department of Biomedical Sciences, College of Health Sciences, Abu Dhabi University, Abu Dhabi P.O. Box 59911, United Arab Emirates
| | - Prabhu Chandra Mishra
- Department of Biotechnology, School of Engineering and Technology, Sharda University, Greater Noida, India
| | - Vinod Kumar Nelson
- Raghavendra Institute of Pharmaceutical Education and Research, Anantapur, India
| | - Niraj Kumar Jha
- Centre for Global Health Research, Saveetha Medical College, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, India; Centre of Research Impact and Outreach, Chitkara University Institute of Engineering and Technology, Chitkara University, Punjab, India; School of Bioengineering & Biosciences, Lovely Professional University, Phagwara 144411, India.
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2
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Monteiro KLC, de Aquino TM, da Silva-Júnior EF. Natural Compounds as Inhibitors of Aβ Peptide and Tau Aggregation. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2024; 23:1234-1250. [PMID: 38018200 DOI: 10.2174/0118715273273539231114095300] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 10/08/2023] [Accepted: 10/16/2023] [Indexed: 11/30/2023]
Abstract
Neurodegenerative conditions like Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS) encompass disorders characterized by the degeneration of neurons in specific circumstances. The quest for novel agents to influence these diseases, particularly AD, has unearthed various natural compounds displaying multifaceted activities and diverse pharmacological mechanisms. Given the ongoing extensive study of pathways associated with the accumulation of neurofibrillary aggregates and amyloid plaques, this paper aims to comprehensively review around 130 studies exploring natural products. These studies focus on inhibiting the formation of amyloid plaques and tau protein tangles, with the objective of potentially alleviating or delaying AD.
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Affiliation(s)
- Kadja Luana Chagas Monteiro
- Research Group on Therapeutic Strategies - GPET, Laboratory of Synthesis and Research in Medicinal Chemistry - LSPMED, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Maceió, Alagoas, Brazil
| | - Thiago Mendonça de Aquino
- Research Group on Therapeutic Strategies - GPET, Laboratory of Synthesis and Research in Medicinal Chemistry - LSPMED, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Maceió, Alagoas, Brazil
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Boiangiu RS, Brinza I, Honceriu I, Mihasan M, Hritcu L. Insights into Pharmacological Activities of Nicotine and 6-Hydroxy-L-nicotine, a Bacterial Nicotine Derivative: A Systematic Review. Biomolecules 2023; 14:23. [PMID: 38254623 PMCID: PMC10813004 DOI: 10.3390/biom14010023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 12/13/2023] [Accepted: 12/20/2023] [Indexed: 01/24/2024] Open
Abstract
The purported cognitive benefits associated with nicotine and its metabolites in the brain are a matter of debate. In this review, the impact of the pharmacologically active metabolite of a nicotine derivative produced by bacteria named 6-hydroxy-L-nicotine (6HLN) on memory, oxidative stress, and the activity of the cholinergic system in the brain was examined. A search in the PubMed, Science Direct, Web of Science, and Google Scholar databases, limiting entries to those published between 1992 and 2023, was conducted. The search focused specifically on articles about nicotine metabolites, memory, oxidative stress, and cholinergic system activity, as well as enzymes or pathways related to nicotine degradation in bacteria. The preliminary search resulted in 696 articles, and following the application of exclusion criteria, 212 articles were deemed eligible for inclusion. This review focuses on experimental studies supporting nicotine catabolism in bacteria, and the chemical and pharmacological activities of nicotine and its metabolite 6HLN.
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Affiliation(s)
| | | | | | - Marius Mihasan
- BioActive Research Group, Department of Biology, Faculty of Biology, Alexandru Ioan Cuza University of Iasi, 700506 Iasi, Romania; (R.S.B.); (I.B.); (I.H.)
| | - Lucian Hritcu
- BioActive Research Group, Department of Biology, Faculty of Biology, Alexandru Ioan Cuza University of Iasi, 700506 Iasi, Romania; (R.S.B.); (I.B.); (I.H.)
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Saba K, Patel AB. Riluzole restores memory and brain energy metabolism in AβPP-PS1 mouse model of Alzheimer's disease. Biochem Biophys Res Commun 2022; 610:140-146. [DOI: 10.1016/j.bbrc.2022.04.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 04/11/2022] [Indexed: 11/02/2022]
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5
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Liu Z, Qin G, Mana L, Dong Y, Huang S, Wang Y, Wu Y, Shi J, Tian J, Wang P. GAPT regulates cholinergic dysfunction and oxidative stress in the brains of learning and memory impairment mice induced by scopolamine. Brain Behav 2020; 10:e01602. [PMID: 32174034 PMCID: PMC7218254 DOI: 10.1002/brb3.1602] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 02/19/2020] [Accepted: 02/25/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Cholinergic dysfunction and oxidative stress are the crucial mechanisms of Alzheimer's disease (AD). GAPT, also called GEPT (a combination of several active components extracted from the Chinese herbs ginseng, epimedium, polygala and tuber curcumae) or Jinsiwei, is a patented Chinese herbal compound, has been clinically widely used to improve learning and memory impairment, but whether it can play a neuroprotective role by protecting cholinergic neurons and reducing oxidative stress injury remains unclear. METHODS Male ICR mice were intraperitoneally injected with scopolamine (3 mg/kg) to establish a learning and memory disordered model. An LC-MS method was established to study the chemical compounds and in vivo metabolites of GAPT. After scopolamine injection, a step-down passive-avoidance test (SDPA) and a Y maze test were used to estimate learning ability and cognitive function. In addition, ELISA detected the enzymatic activities of acetylcholinesterase (AChE), acetylcholine (ACh), choline acetyltransferase (ChAT), malondialdehyde (MDA), glutathione peroxidase (GPX), and total superoxide dismutase (T-SOD). The protein expressions of AChE, ChAT, SOD1, and GPX1 were observed by western blot, and the distribution of ChAT, SOD1, and GPX1 was observed by immunohistochemical staining. RESULTS After one-half or 1 month of intragastric administration, GAPT can ameliorate scopolamine-induced behavioral changes in learning and memory impaired mice. It can also decrease the activity of MDA and protein expression level of AChE, increase the activity of Ach, and increase activity and protein expression level of ChAT, SOD, and GPX in scopolamine-treated mice. After one and a half month of intragastric administration of GAPT, echinacoside, salvianolic acid A, ginsenoside Rb1, ginsenoside Rg2, pachymic acid, and beta asarone could be absorbed into mice blood and pass through BBB. CONCLUSIONS GAPT can improve the learning and memory ability of scopolamine-induced mice, and its mechanism may be related to protecting cholinergic neurons and reducing oxidative stress injury.
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Affiliation(s)
- Zhenhong Liu
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China
| | - Gaofeng Qin
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China
| | - Lulu Mana
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China.,Department of Integrative Medicine, School of TCM, Xinjiang Medical University, Urumqi, China
| | - Yunfang Dong
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China.,Zhongkang International Health Physical Examination Center-Qingdao Ruiyuan Hospital of Traditional Chinese Medicine, Qingdao, China
| | - Shuaiyang Huang
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China
| | - Yahan Wang
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China
| | - Yiqiong Wu
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China.,Jiangsu Province Hospital on Integrated Chinese and Western Medicines, Nanjing, China
| | - Jing Shi
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China.,BUCM Neurology Center, Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Jinzhou Tian
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China.,BUCM Neurology Center, Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Pengwen Wang
- Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital, Beijing University of Chinese Medicine (BUCM), Beijing, China
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Edwards III GA, Gamez N, Escobedo Jr. G, Calderon O, Moreno-Gonzalez I. Modifiable Risk Factors for Alzheimer's Disease. Front Aging Neurosci 2019; 11:146. [PMID: 31293412 PMCID: PMC6601685 DOI: 10.3389/fnagi.2019.00146] [Citation(s) in RCA: 131] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 05/31/2019] [Indexed: 01/03/2023] Open
Abstract
Since first described in the early 1900s, Alzheimer's disease (AD) has risen exponentially in prevalence and concern. Research still drives to understand the etiology and pathogenesis of this disease and what risk factors can attribute to AD. With a majority of AD cases being of sporadic origin, the increasing exponential growth of an aged population and a lack of treatment, it is imperative to discover an easy accessible preventative method for AD. Some risk factors can increase the propensity of AD such as aging, sex, and genetics. Moreover, there are also modifiable risk factors-in terms of treatable medical conditions and lifestyle choices-that play a role in developing AD. These risk factors have their own biological mechanisms that may contribute to AD etiology and pathological consequences. In this review article, we will discuss modifiable risk factors and discuss the current literature of how each of these factors interplay into AD development and progression and if strategically analyzed and treated, could aid in protection against this neurodegenerative disease.
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Affiliation(s)
- George A. Edwards III
- The Mitchell Center for Alzheimer’s Disease and Related Brain Disorders, Department of Neurology, The University of Texas Houston Health Science Center at Houston, Houston, TX, United States
| | - Nazaret Gamez
- The Mitchell Center for Alzheimer’s Disease and Related Brain Disorders, Department of Neurology, The University of Texas Houston Health Science Center at Houston, Houston, TX, United States
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Department of Cell Biology, Facultad Ciencias, Universidad de Malaga, Malaga, Spain
| | - Gabriel Escobedo Jr.
- The Mitchell Center for Alzheimer’s Disease and Related Brain Disorders, Department of Neurology, The University of Texas Houston Health Science Center at Houston, Houston, TX, United States
| | - Olivia Calderon
- The Mitchell Center for Alzheimer’s Disease and Related Brain Disorders, Department of Neurology, The University of Texas Houston Health Science Center at Houston, Houston, TX, United States
| | - Ines Moreno-Gonzalez
- The Mitchell Center for Alzheimer’s Disease and Related Brain Disorders, Department of Neurology, The University of Texas Houston Health Science Center at Houston, Houston, TX, United States
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Department of Cell Biology, Facultad Ciencias, Universidad de Malaga, Malaga, Spain
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7
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Andrade S, Ramalho MJ, Loureiro JA, Pereira MDC. Natural Compounds for Alzheimer's Disease Therapy: A Systematic Review of Preclinical and Clinical Studies. Int J Mol Sci 2019; 20:E2313. [PMID: 31083327 PMCID: PMC6539304 DOI: 10.3390/ijms20092313] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/04/2019] [Accepted: 05/07/2019] [Indexed: 12/31/2022] Open
Abstract
Alzheimer's Disease (AD) is a neurodegenerative disorder related with the increase of age and it is the main cause of dementia in the world. AD affects cognitive functions, such as memory, with an intensity that leads to several functional losses. The continuous increase of AD incidence demands for an urgent development of effective therapeutic strategies. Despite the extensive research on this disease, only a few drugs able to delay the progression of the disease are currently available. In the last years, several compounds with pharmacological activities isolated from plants, animals and microorganisms, revealed to have beneficial effects for the treatment of AD, targeting different pathological mechanisms. Thus, a wide range of natural compounds may play a relevant role in the prevention of AD and have proven to be efficient in different preclinical and clinical studies. This work aims to review the natural compounds that until this date were described as having significant benefits for this neurological disease, focusing on studies that present clinical trials.
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Affiliation(s)
- Stephanie Andrade
- LEPABE, Department of Chemical Engineering, Faculty of Engineering of the University of Porto, 4200-465 Porto, Portugal.
| | - Maria João Ramalho
- LEPABE, Department of Chemical Engineering, Faculty of Engineering of the University of Porto, 4200-465 Porto, Portugal.
| | - Joana Angélica Loureiro
- LEPABE, Department of Chemical Engineering, Faculty of Engineering of the University of Porto, 4200-465 Porto, Portugal.
| | - Maria do Carmo Pereira
- LEPABE, Department of Chemical Engineering, Faculty of Engineering of the University of Porto, 4200-465 Porto, Portugal.
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8
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Alkadhi KA. Neuroprotective Effects of Nicotine on Hippocampal Long-Term Potentiation in Brain Disorders. J Pharmacol Exp Ther 2018; 366:498-508. [DOI: 10.1124/jpet.118.247841] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
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9
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Ferreira-Vieira TH, Guimaraes IM, Silva FR, Ribeiro FM. Alzheimer's disease: Targeting the Cholinergic System. Curr Neuropharmacol 2016; 14:101-15. [PMID: 26813123 PMCID: PMC4787279 DOI: 10.2174/1570159x13666150716165726] [Citation(s) in RCA: 895] [Impact Index Per Article: 111.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 07/01/2015] [Accepted: 07/14/2015] [Indexed: 12/16/2022] Open
Abstract
Acetylcholine (ACh) has a crucial role in the peripheral and central nervous
systems. The enzyme choline acetyltransferase (ChAT) is responsible for
synthesizing ACh from acetyl-CoA and choline in the cytoplasm and the vesicular
acetylcholine transporter (VAChT) uptakes the neurotransmitter into synaptic
vesicles. Following depolarization, ACh undergoes exocytosis reaching the
synaptic cleft, where it can bind its receptors, including muscarinic and
nicotinic receptors. ACh present at the synaptic cleft is promptly hydrolyzed by
the enzyme acetylcholinesterase (AChE), forming acetate and choline, which is
recycled into the presynaptic nerve terminal by the high-affinity choline
transporter (CHT1). Cholinergic neurons located in the basal forebrain,
including the neurons that form the nucleus basalis of Meynert, are severely
lost in Alzheimer’s disease (AD). AD is the most ordinary cause of dementia
affecting 25 million people worldwide. The hallmarks of the disease are the
accumulation of neurofibrillary tangles and amyloid plaques. However, there is
no real correlation between levels of cortical plaques and AD-related cognitive
impairment. Nevertheless, synaptic loss is the principal correlate of disease
progression and loss of cholinergic neurons contributes to memory and attention
deficits. Thus, drugs that act on the cholinergic system represent a promising
option to treat AD patients.
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Affiliation(s)
| | | | | | - Fabiola M Ribeiro
- Departamento de Bioquimica e Imunologia, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
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Chung JK, Nakajima S, Plitman E, Iwata Y, Uy D, Gerretsen P, Caravaggio F, Chakravarty MM, Graff-Guerrero A. Β-Amyloid Burden is Not Associated with Cognitive Impairment in Schizophrenia: A Systematic Review. Am J Geriatr Psychiatry 2016; 24:923-39. [PMID: 27526990 PMCID: PMC5026886 DOI: 10.1016/j.jagp.2016.03.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 01/28/2016] [Accepted: 03/30/2016] [Indexed: 12/31/2022]
Abstract
Current literature suggests that the pathology of schizophrenia (SCZ) has developmental origins. However, the neurodevelopmental theory of SCZ cannot solely explain progressive neurodegenerative processes in the illness. There is evidence of accelerated cognitive decline and increased risk of dementia in elderly patients with SCZ. Investigating β-amyloid (Aβ), we conducted a systematic review focusing on Aβ in patients with SCZ. An OVID literature search using PsychINFO, Medline, and Embase databases was conducted, looking for studies that compared Aβ levels between patients with SCZ and either elderly control subjects, patients with Alzheimer disease (AD), or patients with other psychiatric illnesses. Among 14 identified studies, 11 compared Aβ between SCZ and elderly control subjects, 7 between SCZ and AD, and 3 between SCZ and other psychiatric illnesses. As a result, no evidence was found suggesting that Aβ levels differ in patients with SCZ from elderly control subjects or patients with other psychiatric illnesses. All seven studies reported lower cortical Aβ in patients with SCZ than patients with AD. Furthermore, three of the four studies, which investigated the relationship between Aβ and cognitive impairment in SCZ, observed no association between two factors. The limitations of the included studies are small sample sizes, the inclusion of cerebrospinal fluid Aβ or postmortem plaques rather than cortical Aβ assessment in vivo, and the investigation of different brain regions. In conclusion, Aβ deposition is not associated with cognitive decline in late-life SCZ. Future studies should investigate other neurodegenerative indicators in SCZ to better understand the pathophysiologic mechanisms underlying this illness.
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Affiliation(s)
- Jun Ku Chung
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Multimodal Imaging Group - Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada
| | - Shinichiro Nakajima
- Multimodal Imaging Group - Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada,Department of Psychiatry, University of Toronto, Toronto, Canada,Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo, Japan,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Canada
| | - Eric Plitman
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Multimodal Imaging Group - Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada
| | - Yusuke Iwata
- Multimodal Imaging Group - Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada,Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo, Japan
| | - Danielle Uy
- Multimodal Imaging Group - Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada
| | - Philip Gerretsen
- Multimodal Imaging Group - Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada,Department of Psychiatry, University of Toronto, Toronto, Canada,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Canada
| | - Fernando Caravaggio
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Multimodal Imaging Group - Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Canada
| | - M. Mallar Chakravarty
- Cerebral Imaging Centre, Douglas Mental Health Institute, McGill University, Montreal, Quebec, Canada,Department of Psychiatry and Biomedical Engineering, McGill University, Montreal, Quebec, Canada
| | - Ariel Graff-Guerrero
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Multimodal Imaging Group-Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo, Japan.
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11
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Shen J, Wu J. Nicotinic Cholinergic Mechanisms in Alzheimer's Disease. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 124:275-92. [PMID: 26472533 DOI: 10.1016/bs.irn.2015.08.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative condition characterized by increased accumulation of Aβ and degeneration of cholinergic signaling between basal forebrain and hippocampus. Nicotinic acetylcholine receptors (nAChRs) are important mediators of cholinergic signaling in modulation of learning and memory function. Accumulating lines of evidence indicate that a nAChR subtype, α7 receptor (α7-nAChR), plays an important role in modulations of excitatory neurotransmitter release, improvement of learning and memory ability, and enhancement of cognitive function. Importantly, the expression and function of α7-nAChRs is altered in the brain of AD animal models and AD patients, suggesting that this nAChR subtype participates in AD pathogenesis and may serve as a novel therapeutic target for AD treatment. However, the mechanisms underlying the role of α7-nAChRs in AD pathogenesis are very complex, and either neuroprotective effects or neurotoxic effects may occur through the α7-nAChRs. These effects depend on the levels of α7-nAChR expression and function, disease stages, or the use of α7-nAChR agonists, antagonists, or allosteric modulators. In this chapter, we summarize recent progresses in the roles of α7-nAChRs played in AD pathogenesis and therapy.
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Affiliation(s)
- Jianxin Shen
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong, China
| | - Jie Wu
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong, China; Divisions of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix Arizona, USA.
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12
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Grothe MJ, Ewers M, Krause B, Heinsen H, Teipel SJ. Basal forebrain atrophy and cortical amyloid deposition in nondemented elderly subjects. Alzheimers Dement 2014; 10:S344-53. [PMID: 24418052 PMCID: PMC4092050 DOI: 10.1016/j.jalz.2013.09.011] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 08/09/2013] [Accepted: 09/04/2013] [Indexed: 02/05/2023]
Abstract
BACKGROUND Both neurodegeneration of the cholinergic basal forebrain (BF) and deposition of β-amyloid are early events in the course of Alzheimer's disease (AD). Associations between increased amyloid pathology and cholinergic atrophy have been described in autopsy studies. METHODS We used structural MRI and AV45-PET amyloid imaging data of 225 cognitively normal or mildly impaired elderly subjects from the Alzheimer's Disease Neuroimaging Initiative to assess in vivo associations between BF atrophy and cortical amyloid deposition. Associations were examined using region-of-interest (ROI) and voxel-based approaches with reference to cytoarchitectonic mappings of the cholinergic BF nuclei. RESULTS ROI- and voxel-based approaches yielded complementary evidence for an association between BF volume and cortical amyloid deposition in presymptomatic and predementia stages of AD, irrespective of age, gender, and APOE genotype. CONCLUSIONS The observed correlations between BF atrophy and cortical amyloid load likely reflect associations between cholinergic degeneration and amyloid pathology as reported in neuropathologic examination studies.
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Affiliation(s)
- Michel J Grothe
- German Center for Neurodegenerative Diseases (DZNE), Rostock, Germany.
| | - Michael Ewers
- Institute for Stroke and Dementia Research, Klinikum Grosshadern, Ludwig-Maximilians University, Munich, Germany
| | - Bernd Krause
- Department of Nuclear Medicine, University of Rostock, Rostock, Germany
| | - Helmut Heinsen
- Laboratory of Morphological Brain Research, Department of Psychiatry, University of Würzburg, Würtzburg, Germany
| | - Stefan J Teipel
- German Center for Neurodegenerative Diseases (DZNE), Rostock, Germany; Department of Psychosomatic Medicine, University of Rostock, Rostock, Germany
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13
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Ma L, Turner D, Zhang J, Wang Q, Wang M, Shen J, Zhang S, Wu J. Deficits of synaptic functions in hippocampal slices prepared from aged mice null α7 nicotinic acetylcholine receptors. Neurosci Lett 2014; 570:97-101. [DOI: 10.1016/j.neulet.2014.04.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 04/10/2014] [Accepted: 04/16/2014] [Indexed: 01/24/2023]
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14
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Durazzo TC, Mattsson N, Weiner MW. Smoking and increased Alzheimer's disease risk: a review of potential mechanisms. Alzheimers Dement 2014; 10:S122-45. [PMID: 24924665 PMCID: PMC4098701 DOI: 10.1016/j.jalz.2014.04.009] [Citation(s) in RCA: 251] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Cigarette smoking has been linked with both increased and decreased risk for Alzheimer's disease (AD). This is relevant for the US military because the prevalence of smoking in the military is approximately 11% higher than in civilians. METHODS A systematic review of published studies on the association between smoking and increased risk for AD and preclinical and human literature on the relationships between smoking, nicotine exposure, and AD-related neuropathology was conducted. Original data from comparisons of smoking and never-smoking cognitively normal elders on in vivo amyloid imaging are also presented. RESULTS Overall, literature indicates that former/active smoking is related to a significantly increased risk for AD. Cigarette smoke/smoking is associated with AD neuropathology in preclinical models and humans. Smoking-related cerebral oxidative stress is a potential mechanism promoting AD pathology and increased risk for AD. CONCLUSIONS A reduction in the incidence of smoking will likely reduce the future prevalence of AD.
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Affiliation(s)
- Timothy C Durazzo
- Center for Imaging of Neurodegenerative Diseases (CIND), San Francisco VA Medical Center, San Francisco, CA, USA; Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA.
| | - Niklas Mattsson
- Center for Imaging of Neurodegenerative Diseases (CIND), San Francisco VA Medical Center, San Francisco, CA, USA; Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Michael W Weiner
- Center for Imaging of Neurodegenerative Diseases (CIND), San Francisco VA Medical Center, San Francisco, CA, USA; Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; Department of Psychiatry, University of California, San Francisco, San Francisco, CA, USA; Department of Medicine, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
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15
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Verhoeff NPLG. Acetylcholinergic neurotransmission and the β-amyloid cascade: implications for Alzheimer’s disease. Expert Rev Neurother 2014; 5:277-84. [PMID: 15853497 DOI: 10.1586/14737175.5.2.277] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Alzheimer's disease is characterized by both decreases in acetylcholinergic neurotransmission and increases in beta-amyloid accumulation. Currently, available clinical psychopharmacologic treatment is focused on increasing acetylcholinergic neurotransmission, whereas no clinical treatments to directly reduce beta-amyloid accumulation are available. Cholinesterase inhibitors improve cognition, certain neuropsychiatric symptoms and functional impairment in patients with mild-to-moderate Alzheimer's disease, and it is believed that this is mainly symptomatic treatment. However, this review discusses various levels of interaction between acetylcholinergic neurotransmission and the beta-amyloid cascade, which suggest that some specific acetylcholinergic treatments may reduce beta-amyloid accumulation, and therefore may slow disease progression over the long term. Various suggestions are made on how such potential disease-modifying effects could be studied in the future.
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16
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Moreno-Gonzalez I, Estrada LD, Sanchez-Mejias E, Soto C. Smoking exacerbates amyloid pathology in a mouse model of Alzheimer's disease. Nat Commun 2013; 4:1495. [PMID: 23422663 DOI: 10.1038/ncomms2494] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 01/15/2013] [Indexed: 12/18/2022] Open
Abstract
Several epidemiological studies have shown that cigarette smoking might alter the incidence of Alzheimer's disease. However, inconsistent results have been reported regarding the risk of Alzheimer's disease among smokers. Previous studies in experimental animal models have reported that administration of some cigarette components (for example, nicotine) alters amyloid-β aggregation, providing a possible link. However, extrapolation of these findings towards the in vivo scenario is not straightforward as smoke inhalation involves a number of other components. Here, we analysed the effect of smoking under more relevant conditions. We exposed transgenic mouse models of Alzheimer's disease to cigarette smoke and analysed the neuropathological alterations in comparison with animals not subjected to smoke inhalation. Our results showed that smoking increases the severity of some abnormalities typical of Alzheimer's disease, including amyloidogenesis, neuroinflammation and tau phosphorylation. Our findings suggest that cigarette smoking may increase Alzheimer's disease onset and exacerbate its features and thus, may constitute an important environmental risk factor for Alzheimer's disease.
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Affiliation(s)
- Ines Moreno-Gonzalez
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas Medical School at Houston, Houston, Texas, USA
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17
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Liu Q, Huang Y, Shen J, Steffensen S, Wu J. Functional α7β2 nicotinic acetylcholine receptors expressed in hippocampal interneurons exhibit high sensitivity to pathological level of amyloid β peptides. BMC Neurosci 2012; 13:155. [PMID: 23272676 PMCID: PMC3573893 DOI: 10.1186/1471-2202-13-155] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 12/18/2012] [Indexed: 11/10/2022] Open
Abstract
Background β-amyloid (Aβ) accumulation is described as a hallmark of Alzheimer’s disease (AD). Aβ perturbs a number of synaptic components including nicotinic acetylcholine receptors containing α7 subunits (α7-nAChRs), which are abundantly expressed in the hippocampus and found on GABAergic interneurons. We have previously demonstrated the existence of a novel, heteromeric α7β2-nAChR in basal forebrain cholinergic neurons that exhibits high sensitivity to acute Aβ exposure. To extend our previous work, we evaluated the expression and pharmacology of α7β2-nAChRs in hippocampal interneurons and their sensitivity to Aβ. Results GABAergic interneurons in the CA1 subregion of the hippocampus expressed functional α7β2-nAChRs, which were characterized by relatively slow whole-cell current kinetics, pharmacological sensitivity to dihydro-β-erythroidine (DHβE), a nAChR β2* subunit selective blocker, and α7 and β2 subunit interaction using immunoprecipitation assay. In addition, α7β2-nAChRs were sensitive to 1 nM oligomeric Aβ. Similar effects were observed in identified hippocampal interneurons prepared from GFP-GAD mice. Conclusion These findings suggest that Aβ modulation of cholinergic signaling in hippocampal GABAergic interneurons via α7β2-nAChRs could be an early and critical event in Aβ-induced functional abnormalities of hippocampal function, which may be relevant to learning and memory deficits in AD.
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Affiliation(s)
- Qiang Liu
- Divisions of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013-4496, USA
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18
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Alkadhi KA. Chronic stress and Alzheimer's disease-like pathogenesis in a rat model: prevention by nicotine. Curr Neuropharmacol 2012; 9:587-97. [PMID: 22654719 PMCID: PMC3263455 DOI: 10.2174/157015911798376307] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 02/10/2011] [Accepted: 06/10/2011] [Indexed: 01/08/2023] Open
Abstract
Environmental factors including chronic stress may play a critical role in the manifestation of Alzheimer's disease (AD).This review summarizes our studies of the aggravation of the impaired cognitive ability and its cellular and molecular correlates by chronic psychosocial stress and prevention by nicotine in an Aβ rat model of AD. We utilized three approaches: learning and memory tests in the radial arm water maze, electrophysiological recordings of the cellular correlates of memory, long-term potentiation (LTP) and long-term depression (LTD), in anesthetized rats, and immunoblot analysis of synaptic plasticity- and cognition-related signaling molecules. The Aβ rat model, representing the sporadic form of established AD, was induced by continuous i.c.v. infusion of a pathogenic dose of Aβ peptides via a 14- day osmotic pump. In this AD model, chronic stress intensified cognitive deficits, accentuated the disruption of signaling molecules levels and produced greater depression of LTP than what was seen with Aβ infusion alone. Chronic treatment with nicotine was highly efficient in preventing the effects of Aβ infusion and the exacerbating impact of chronic stress. Possible mechanisms for the effect of chronic stress are discussed.
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Affiliation(s)
- Karim A Alkadhi
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204, USA
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19
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Elevation of BACE in an Aβ rat model of Alzheimer's disease: exacerbation by chronic stress and prevention by nicotine. Int J Neuropsychopharmacol 2012; 15:223-33. [PMID: 21356140 DOI: 10.1017/s1461145711000162] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In Alzheimer's disease (AD), progressive accumulation of β-amyloid (Aβ) peptides impairs nicotinic acetylcholine receptor (nAChR) function by a mechanism that may involve α7 and α4β2-nAChR subtypes. Additionally, the beta-site amyloid precursor protein (APP)-cleaving enzyme (BACE), the rate-limiting enzyme in the pathogenic Aβ production pathway, is expressed at high levels in hippocampal and cortical regions of AD brains. We measured hippocampal area CA1 protein levels of BACE and α7- and α4β2-nAChR subunits using an Aβ rat model of AD (14-d osmotic pump i.c.v. infusion of 300 pmol/d Aβ peptides) in the presence and absence of chronic stress and/or chronic nicotine treatment. There was a significant increase in the levels of BACE in Aβ-infused rats, which were markedly intensified by chronic (4-6 wk) stress, but were normalized in Aβ rats chronically treated with nicotine (1 mg/kg b.i.d.). The levels of the three subunits α7, α4 and β2 were significantly decreased in Aβ rats, but these were also normalized in Aβ rats chronically treated with nicotine. Chronic stress did not further aggravate the reduction of nAChRs in Aβ-infused rats. The increased BACE levels and decreased nAChR levels, which are established hallmarks of AD, provide additional support for the validity of the Aβ i.c.v.-infused rat as a model of AD.
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20
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Scerri C, Stewart CA, Balfour DJK, Breen KC. Nicotine modifies in vivo and in vitro rat hippocampal amyloid precursor protein processing in young but not old rats. Neurosci Lett 2012; 514:22-6. [PMID: 22381398 DOI: 10.1016/j.neulet.2012.02.042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 02/08/2012] [Accepted: 02/13/2012] [Indexed: 11/30/2022]
Abstract
Previous studies have shown that administration of nicotine modifies the expression and secretion of amyloid precursor protein (APP) in various cell lines. The present study investigated the extent to which chronic subcutaneous nicotine administration influences APP levels and processing in cerebral cortex, striatum and hippocampus of young and old rat brains. The results showed that constant nicotine infusion (0.25 or 4.00mg/kg/day) increased the levels of particulate APP (APPp) but not secreted APP (APPs) in the hippocampus of young rats in vivo. This response to nicotine was not observed in the striatum or cerebral cortex of young rats or in any of the brain regions examined in old animals. Subsequent in vitro analysis demonstrated that nicotine enhanced the release of APPs from hippocampal slice preparations and that this increase was attenuated by mecamylamine, a non-selective nicotinic acetylcholine receptor (nAChR) antagonist. The in vitro effect of nicotine on APPs was age-related, being only detected from hippocampal slices derived from the young but not the older animals. These results suggest that nicotine modulates APP expression and secretion in the hippocampus and that the responses observed to the drug are age-dependent being only detected in younger rats.
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Affiliation(s)
- Charles Scerri
- Division of Neuroscience, Medical Research Institute, University of Dundee, Ninewells Hospital & Medical School, Dundee DD1 9SY, UK.
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21
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Srivareerat M, Tran TT, Salim S, Aleisa AM, Alkadhi KA. Chronic nicotine restores normal Aβ levels and prevents short-term memory and E-LTP impairment in Aβ rat model of Alzheimer's disease. Neurobiol Aging 2009; 32:834-44. [PMID: 19464074 DOI: 10.1016/j.neurobiolaging.2009.04.015] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Revised: 04/15/2009] [Accepted: 04/19/2009] [Indexed: 11/19/2022]
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disorder characterized by increased deposition of beta-amyloid (Aβ) peptides and progressive cholinergic dysfunction in regions of the brain involved in learning and memory processing. In AD, progressive accumulation of Aβ peptide impairs nicotinic acetylcholine receptor (nAChR) function by an unknown mechanism believed to involve α(7)- and α(4)β(2)-nAChR blockade. The three approaches of the current study evaluated the effects of chronic nicotine treatment in the prevention of Aβ-induced impairment of learning and short-term memory. Rat AD model was induced by 14-day i.c.v. osmotic pump infusion of a 1:1 mixture of 300 pmol/day Aβ(1-40)/Aβ(1-42) or Aβ(40-1) (inactive peptide, control). The effect of nicotine (2 mg/(kg day)) on Aβ-induced spatial learning and memory impairments was assessed by evaluation of performance in the radial arm water maze (RAWM), in vivo electrophysiological recordings of early-phase long-term potentiation (E-LTP) in urethane-anesthetized rats, and immunoblot analysis to determine changes in the levels of beta-site amyloid precursor protein (APP)-cleaving enzyme (BACE), Aβ and memory-related proteins. The results indicate that 6 weeks of nicotine treatment reduced the levels of Aβ(1-40) and BACE1 peptides in hippocampal area CA1 and prevented Aβ-induced impairment of learning and short-term memory. Chronic nicotine also prevented the Aβ-induced inhibition of basal synaptic transmission and LTP in hippocampal area CA1. Furthermore, chronic nicotine treatment prevented the Aβ-induced reduction of α(7)- and α(4)-nAChR. These effects of nicotine may be due, at least in part, to upregulation of brain derived neurotropic factor (BDNF).
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Affiliation(s)
- Marisa Srivareerat
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204, United States
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22
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Buckingham SD, Jones AK, Brown LA, Sattelle DB. Nicotinic acetylcholine receptor signalling: roles in Alzheimer's disease and amyloid neuroprotection. Pharmacol Rev 2009; 61:39-61. [PMID: 19293145 DOI: 10.1124/pr.108.000562] [Citation(s) in RCA: 208] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Alzheimer's disease (AD), the major contributor to dementia in the elderly, involves accumulation in the brain of extracellular plaques containing the beta-amyloid protein (Abeta) and intracellular neurofibrillary tangles of hyperphosphorylated tau protein. AD is also characterized by a loss of neurons, particularly those expressing nicotinic acetylcholine receptors (nAChRs), thereby leading to a reduction in nAChR numbers. The Abeta(1-42) protein, which is toxic to neurons, is critical to the onset and progression of AD. The discovery of new drug therapies for AD is likely to be accelerated by an improved understanding of the mechanisms whereby Abeta causes neuronal death. We examine the evidence for a role in Abeta(1-42) toxicity of nAChRs; paradoxically, nAChRs can also protect neurons when activated by nicotinic ligands. Abeta peptides and nicotine differentially activate several intracellular signaling pathways, including the phosphatidylinositol 3-kinase/v-akt murine thymoma viral oncogene homolog pathway, the extracellular signal-regulated kinase/mitogen-activated protein kinase, and JAK-2/STAT-3 pathways. These pathways control cell death or survival and the secretion of Abeta peptides. We propose that understanding the differential activation of these pathways by nicotine and/or Abeta(1-42) may offer the prospect of new routes to therapy for AD.
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Affiliation(s)
- Steven D Buckingham
- Medical Research Council Functional Genomics Unit, Department of Physiology Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, UK, OX1 3QX
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23
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Nicotinic receptor agonists and antagonists increase sAPPα secretion and decrease Aβ levels in vitro. Neurochem Int 2009; 54:237-44. [DOI: 10.1016/j.neuint.2008.12.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 11/19/2008] [Accepted: 12/02/2008] [Indexed: 02/01/2023]
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24
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Liu Q, Huang Y, Xue F, Simard A, DeChon J, Li G, Zhang J, Lucero L, Wang M, Sierks M, Hu G, Chang Y, Lukas RJ, Wu J. A novel nicotinic acetylcholine receptor subtype in basal forebrain cholinergic neurons with high sensitivity to amyloid peptides. J Neurosci 2009; 29:918-29. [PMID: 19176801 PMCID: PMC2857410 DOI: 10.1523/jneurosci.3952-08.2009] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 12/02/2008] [Accepted: 12/16/2008] [Indexed: 11/21/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) containing alpha7 subunits are thought to assemble as homomers. alpha7-nAChR function has been implicated in learning and memory, and alterations of alpha7-nAChR have been found in patients with Alzheimer's disease (AD). Here we report findings consistent with a novel, naturally occurring nAChR subtype in rodent, basal forebrain cholinergic neurons. In these cells, alpha7 subunits are coexpressed, colocalize, and coassemble with beta2 subunit(s). Compared with homomeric alpha7-nAChRs from ventral tegmental area neurons, functional, presumably heteromeric alpha7beta2-nAChRs on cholinergic neurons freshly dissociated from medial septum/diagonal band (MS/DB) exhibit relatively slow kinetics of whole-cell current responses to nicotinic agonists and are more sensitive to the beta2 subunit-containing nAChR-selective antagonist, dihydro-beta-erythroidine (DHbetaE). Interestingly, presumed, heteromeric alpha7beta2-nAChRs are highly sensitive to functional inhibition by pathologically relevant concentrations of oligomeric, but not monomeric or fibrillar, forms of amyloid beta(1-42) (Abeta(1-42)). Slow whole-cell current kinetics, sensitivity to DHbetaE, and specific antagonism by oligomeric Abeta(1-42) also are characteristics of heteromeric alpha7beta2-nAChRs, but not of homomeric alpha7-nAChRs, heterologously expressed in Xenopus oocytes. Moreover, choline-induced currents have faster kinetics and less sensitivity to Abeta when elicited from MS/DB neurons derived from nAChR beta2 subunit knock-out mice rather than from wild-type mice. The presence of novel, functional, heteromeric alpha7beta2-nAChRs on basal forebrain cholinergic neurons and their high sensitivity to blockade by low concentrations of oligomeric Abeta(1-42) suggests possible mechanisms for deficits in cholinergic signaling that could occur early in the etiopathogenesis of AD and might be targeted by disease therapies.
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MESH Headings
- Acetylcholine/metabolism
- Acetylcholine/pharmacology
- Amyloid beta-Peptides/pharmacology
- Animals
- Animals, Newborn
- Cells, Cultured
- Choline O-Acetyltransferase/metabolism
- Cholinergic Agents/pharmacology
- Dose-Response Relationship, Drug
- Immunoprecipitation/methods
- Membrane Potentials/drug effects
- Membrane Potentials/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Neurons/drug effects
- Neurons/metabolism
- Oocytes
- Patch-Clamp Techniques/methods
- Peptide Fragments/pharmacology
- Prosencephalon/cytology
- Protein Subunits/genetics
- Protein Subunits/metabolism
- Rats
- Rats, Wistar
- Receptors, Nicotinic/chemistry
- Receptors, Nicotinic/deficiency
- Receptors, Nicotinic/genetics
- Receptors, Nicotinic/metabolism
- Xenopus laevis
- alpha7 Nicotinic Acetylcholine Receptor
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Affiliation(s)
| | - Yao Huang
- Department of Obstetrics and Gynecology, St. Joseph's Hospital and Medical Center, Phoenix, Arizona 85004
| | - Fenqin Xue
- Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona 85013-4496
| | - Alain Simard
- Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona 85013-4496
| | | | | | - Jianliang Zhang
- Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona 85013-4496
| | - Linda Lucero
- Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona 85013-4496
| | - Min Wang
- Department of Chemical Engineering, Arizona State University, Tempe, Arizona 85281, and
| | - Michael Sierks
- Department of Chemical Engineering, Arizona State University, Tempe, Arizona 85281, and
| | - Gang Hu
- Department of Pharmacology, Nanjing Medical University, Nanjing 210029, People's Republic of China
| | - Yongchang Chang
- Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona 85013-4496
| | - Ronald J. Lukas
- Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona 85013-4496
| | - Jie Wu
- Divisions of Neurology and
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Sabri O, Kendziorra K, Wolf H, Gertz HJ, Brust P. Acetylcholine receptors in dementia and mild cognitive impairment. Eur J Nucl Med Mol Imaging 2008; 35 Suppl 1:S30-45. [PMID: 18228017 DOI: 10.1007/s00259-007-0701-1] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE To clarify whether changes in the cholinergic transmission occur early in the course of Alzheimer's disease (AD), we carried out positron emission tomography (PET) with the radioligand 2-[(18)F]F-A-85380, which is supposed to be specific for alpha4beta2 nicotinic acetylcholine receptors (nAChRs). METHOD We included patients with moderate to severe AD and patients with amnestic mild cognitive impairment (MCI), presumed to present preclinical AD. RESULTS Both patients with AD and MCI showed significant reductions in alpha4beta2 nAChRs in brain regions typically affected by AD pathology. These findings indicate that a reduction in alpha4beta2 nAChRs occurs during early symptomatic stages of AD. The alpha4beta2 nAChR availability in these regions correlated with the severity of cognitive impairment, indicating a stage sensitivity of the alpha4beta2 nAChR status. CONCLUSION Together, our results provide evidence for the potential of 2-[(18)]F-A-85380 nAChR PET in the diagnosis of patients at risk for AD. Because of the extraordinary long acquisition time with 2-[(18)F]F-A-85380, we developed the new alpha4beta2 nAChR-specific radioligands (+)- and (-)-[(18)F]norchloro-fluoro-homoepibatidine (NCFHEB) and evaluated them preclinically. (-)-[(18)F]NCFHEB shows twofold higher brain uptake and significantly shorter acquisition times. Therefore, (-)-[(18)F]NCFHEB should be a suitable radioligand for larger clinical investigations.
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Affiliation(s)
- Osama Sabri
- Department of Nuclear Medicine, University of Leipzig, Stephanstrasse 11, Leipzig, Germany.
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26
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Cholinergic and glutamatergic alterations beginning at the early stages of Alzheimer disease: participation of the phospholipase A2 enzyme. Psychopharmacology (Berl) 2008; 198:1-27. [PMID: 18392810 DOI: 10.1007/s00213-008-1092-0] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Accepted: 01/28/2008] [Indexed: 12/14/2022]
Abstract
RATIONALE Alzheimer disease (AD), a progressive neurodegenerative disorder, is the leading cause of dementia in the elderly. A combination of cholinergic and glutamatergic dysfunction appears to underlie the symptomatology of AD, and thus, treatment strategies should address impairments in both systems. Evidence suggests the involvement of phospholipase A(2) (PLA(2)) enzyme in memory impairment and neurodegeneration in AD via actions on both cholinergic and glutamatergic systems. OBJECTIVES To review cholinergic and glutamatergic alterations underlying cognitive impairment and neuropathology in AD and attempt to link PLA(2) with such alterations. METHODS Medline databases were searched (no date restrictions) for published articles with links among the terms Alzheimer disease (mild, moderate, severe), mild cognitive impairment, choline acetyltransferase, acetylcholinesterase, NGF, NGF receptor, muscarinic receptor, nicotinic receptor, NMDA, AMPA, metabotropic glutamate receptor, atrophy, glucose metabolism, phospholipid metabolism, sphingolipid, membrane fluidity, phospholipase A(2), arachidonic acid, attention, memory, long-term potentiation, beta-amyloid, tau, inflammation, and reactive species. Reference lists of the identified articles were checked to identify additional studies of interest. RESULTS Overall, results suggest the hypothesis that persistent inhibition of cPLA(2) and iPLA(2) isoforms at early stages of AD may play a central role in memory deficits and beta-amyloid production through down-regulation of cholinergic and glutamate receptors. As the disease progresses, beta-amyloid induced up-regulation of cPLA(2) and sPLA(2) isoforms may play critical roles in inflammation and oxidative stress, thus participating in the neurodegenerative process. CONCLUSION Activation and inhibition of specific PLA(2) isoforms at different stages of AD could be of therapeutic importance and delay cognitive dysfunction and neurodegeneration.
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27
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Chen G, Chen P, Tan H, Ma D, Dou F, Feng J, Yan Z. Regulation of the NMDA receptor-mediated synaptic response by acetylcholinesterase inhibitors and its impairment in an animal model of Alzheimer's disease. Neurobiol Aging 2007; 29:1795-804. [PMID: 17555845 PMCID: PMC2613405 DOI: 10.1016/j.neurobiolaging.2007.04.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Revised: 03/30/2007] [Accepted: 04/30/2007] [Indexed: 10/23/2022]
Abstract
The cholinergic system is crucial for cognitive processes and the deficient acetylcholine (ACh) function has been implicated in Alzheimer's disease (AD). Inhibitors of acetylcholinesterase (AChE), which act to enhance cholinergic function by prolonging the action of endogenously released ACh, have been used as the major therapy of AD. To understand the functional roles of cholinergic enhancement in prefrontal cortex (PFC), a key brain region for cognition, we examined the impact of AChE inhibitors in PFC neurons on synaptic responses mediated by the NMDA receptor (NMDAR), an important player in learning and memory. We found that AChE inhibitors produced a strong and persistent reduction of the amplitude of NMDA receptor-mediated excitatory postsynaptic current (NMDAR-EPSC). This effect was mainly mediated by nicotinic ACh receptors, and through a Ca(2+)-dependent mechanism. Inhibition of extracellular signal-regulated kinases (ERK) abolished the regulation of NMDAR function by AChE inhibitors, suggesting the involvement of ERK. In the transgenic mouse model of AD overexpressing mutant beta-amyloid precursor protein (APP), the effect of AChE inhibitors on NMDAR-EPSC was significantly impaired, which was associated with their diminished effect on ERK activation. Taken together, these results suggest that one of the key targets of endogenous ACh involved in cognition is the NMDAR-mediated transmission. Loss of the regulation of synaptic NMDAR responses by endogenous ACh may contribute to the cognitive deficiency in AD.
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Affiliation(s)
- Guojun Chen
- Dept. of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, NY
| | - Paul Chen
- Dept. of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, NY
| | - Huibing Tan
- Dept. of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, NY
| | - Da Ma
- Dept. Genetics and Development Biology, Southeast University Medical School, Nanjing, China
| | - Fei Dou
- Dept. Genetics and Development Biology, Southeast University Medical School, Nanjing, China
| | - Jian Feng
- Dept. of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, NY
- New York State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY
| | - Zhen Yan
- Dept. of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, NY
- New York State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY
- Correspondence should be addressed to Zhen Yan, Ph.D., Department of Physiology and Biophysics, State University of New York at Buffalo, 124 Sherman Hall, Buffalo, NY, 14214, USA. . Tel: 716-829-3058. Fax: 716-829-2699
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28
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Schliebs R, Arendt T. The significance of the cholinergic system in the brain during aging and in Alzheimer's disease. J Neural Transm (Vienna) 2006; 113:1625-44. [PMID: 17039298 DOI: 10.1007/s00702-006-0579-2] [Citation(s) in RCA: 374] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Accepted: 09/27/2006] [Indexed: 12/11/2022]
Abstract
Acetylcholine is widely distributed in the nervous system and has been implicated to play a critical role in cerebral cortical development, cortical activity, controlling cerebral blood flow and sleep-wake cycle as well as in modulating cognitive performances and learning and memory processes. Cholinergic neurons of the basal forebrain complex have been described to undergo moderate degenerative changes during aging, resulting in cholinergic hypofunction that has been related to the progressing memory deficits with aging. Basal forebrain cholinergic cell loss is also a consistent feature of Alzheimer's disease, which has been suggested to cause, at least partly, the cognitive deficits observed, and has led to the formulation of the cholinergic hypotheses of geriatric memory dysfunction. Impaired cortical cholinergic neurotransmission may also contribute to beta-amyloid plaque pathology and increase phosphorylation of tau protein the main component of neurofibrillar tangles in Alzheimer's disease. Understanding the molecular mechanisms underlying the interrelationship between cortical cholinergic dysfunction, beta-amyloid formation and deposition, and tau pathology in Alzheimer's disease, would allow to derive potential treatment strategies to pharmacologically intervene in the disease-causing signaling cascade.
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Affiliation(s)
- R Schliebs
- Department of Neurochemistry, Paul Flechsig Institute for Brain Research, University of Leipzig, Leipzig, Germany.
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Gutala R, Wang J, Hwang YY, Haq R, Li MD. Nicotine modulates expression of amyloid precursor protein and amyloid precursor-like protein 2 in mouse brain and in SH-SY5Y neuroblastoma cells. Brain Res 2006; 1093:12-9. [PMID: 16707114 DOI: 10.1016/j.brainres.2006.03.100] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Revised: 03/13/2006] [Accepted: 03/22/2006] [Indexed: 12/22/2022]
Abstract
Epidemiological studies indicate that tobacco smoking can be protective against neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). The objective of the present study was to examine the changes in gene expression induced by chronic oral nicotine administration (100 mug/ml in 2% saccharin for 14 days), with special emphasis on amyloid precursor protein (APP) and its homologue, amyloid precursor-like protein 2 (APLP2), in different brain regions of C57BL/6 mice using a pathway-focused microarray. Our results revealed that nicotine stimulated mRNA expression of APP in the amygdala (64%; P = 0.003) and hippocampus (32%; P = 0.034) and of APLP2 in the amygdala (39%; P = 0.002). These results were verified by quantitative real-time RT-PCR except that expression of APLP2 was also significantly upregulated by nicotine in the hippocampus. In addition, in vitro nicotine treatment of SH-SY5Y neuroblastoma cells resulted in a significant increase in expression of APP protein, soluble APP, and APLP2, whereas co-treatment with mecamylamine (an antagonist of nicotinic acetylcholine receptors) attenuated the stimulating effect of nicotine on APP and APLP2 expression. These findings suggest that nicotine treatment facilitates the increase in the expression of mRNA and protein of the APP and APLP2 genes in rat brain and SH-SY5Y neuroblastoma cells.
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Affiliation(s)
- Ramana Gutala
- Department of Psychiatric Medicine, Section of Neurobiology, University of Virginia, 1670 Discovery Drive, Suite 110, Charlottesville, VA 22911, USA
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Schliebs R. Basal forebrain cholinergic dysfunction in Alzheimer's disease--interrelationship with beta-amyloid, inflammation and neurotrophin signaling. Neurochem Res 2006; 30:895-908. [PMID: 16187224 DOI: 10.1007/s11064-005-6962-9] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2005] [Indexed: 12/21/2022]
Abstract
Alzheimer's disease, the most common neurodegenerative disorder of senile dementia, is characterized by two major morpho-pathological hallmarks. Deposition of extracellular neuritic, beta-amyloid peptide-containing plaques (senile plaques) in cerebral cortical regions of Alzheimer patients is accompanied by the presence of intracellular neurofibrillary tangles in cerebral pyramidal neurons. Basal forebrain cholinergic dysfunction is also a consistent feature of Alzheimer's disease, which has been suggested to cause, at least partly, the cognitive deficits observed in patients with Alzheimer's disease. Impaired cortical cholinergic neurotransmission may also contribute to beta-amyloid plaque pathology in Alzheimer's disease by affecting expression and processing of the beta-amyloid precursor protein (APP). Vice versa, low level of soluble beta-amyloid has been observed to inhibit cholinergic synaptic function. Deposition of beta-amyloid plaques in Alzheimer's disease is also accompanied by a significant plaque-associated glial up-regulation of interleukin-1, which has been attributed to affect expression and metabolism of APP and to interfere with cholinergic transmission. Understanding the molecular mechanisms underlying the interrelationship between cortical cholinergic dysfunction, beta-amyloid formation and deposition, as well as local inflammatory upregulation, would allow to derive potential treatment strategies to pharmacologically intervene in the disease-causing signaling cascade.
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Affiliation(s)
- Reinhard Schliebs
- Paul Flechsig Institute for Brain Research, Department of Neurochemistry, University of Leipzig, Jahnallee 59, D-04109 Leipzig, Germany.
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Abstract
The prevalence of dementia is growing in developed countries where elderly patients are increasing in numbers. Neurotransmission modulation is one approach to the treatment of dementia. Cholinergic precursors, anticholinesterases, nicotine receptor agonists and muscarinic M(2) receptor antagonists are agents that enhance cholinergic neurotransmission and that depend on having some intact cholinergic innervation to be effective in the treatment of dementia. The cholinergic precursor choline alfoscerate may be emerging as a potential useful drug in the treatment of dementia, with few adverse effects. Of the anticholinesterases, donepezil, in addition to having a similar efficacy to tacrine in mild-to-moderate Alzheimer's disease (AD), appears to have major advantages; its use is associated with lower drop-out rates in clinical trials, a lower incidence of cholinergic-like side effects and no liver toxicity. Rivastigmine is efficacious in the treatment in dementia with Lewy bodies, a condition in which the other anticholinesterases have not been tested extensively to date. Galantamine is an anticholinesterase and also acts as an allosteric potentiating modulator at nicotinic receptors to increase the release of acetylcholine. Pooled data from clinical trials of patients with mild-to-moderate AD suggest that the benefits and safety profile of galantamine are similar to those of the anticholinesterases. Selective nicotine receptor agonists are being developed that enhance cognitive performance without influencing autonomic and skeletal muscle function, but these have not yet entered clinical trial for dementia. Unlike the cholinergic enhancers, the M(1) receptor agonists do not depend upon intact cholinergic nerves but on intact M(1) receptors for their action, which are mainly preserved in AD and dementia with Lewy bodies. The M(1) receptor-selective agonists developed to date have shown limited efficacy in clinical trials and have a high incidence of side effects. A major recent advancement in the treatment of dementia is memantine, a non-competitive antagonist at NMDA receptors. Memantine is beneficial in the treatment of severe and moderate-to-severe AD and may also be of some benefit in the treatment of mild-to-moderate vascular dementia. Drugs that modulate 5-HT, somatostatin and noradrenergic neurotransmission are also being considered for the treatment of dementia.
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Affiliation(s)
- Sheila A Doggrell
- School of Biomedical Sciences, the University of Queensland, QLD 4072, Australia
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Francis PT, Nordberg A, Arnold SE. A preclinical view of cholinesterase inhibitors in neuroprotection: do they provide more than symptomatic benefits in Alzheimer's disease? Trends Pharmacol Sci 2005; 26:104-11. [PMID: 15681028 DOI: 10.1016/j.tips.2004.12.010] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The prevalence of Alzheimer's disease (AD), a neurodegenerative condition whose greatest risk factor is old age, is expected to rise dramatically during the next five decades, along with the trend for increased longevity. Early diagnosis and intervention with therapies that halt or slow disease progress are likely to represent an important component of effective treatment. Although much progress has been made in this area, there are currently no clinically approved interventions for AD that are classed as disease modifying or neuroprotective. Cholinesterase inhibitors are a drug class used for the symptomatic treatment of AD. Recent evidence from preclinical studies indicates that these agents can attenuate neuronal damage and death from cytotoxic insults, and therefore might affect AD pathogenesis. The mechanisms by which these actions are mediated might or might not be directly related to their primary mode of action.
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Affiliation(s)
- Paul T Francis
- Wolfson Centre for Age-Related Diseases, Guy's Campus, St Thomas Street, Kings College London, London SE1 1UL, UK.
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