1
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Palumbo TB, Miwa JM. Lynx1 and the family of endogenous mammalian neurotoxin-like proteins and their roles in modulating nAChR function. Pharmacol Res 2023; 194:106845. [PMID: 37437646 DOI: 10.1016/j.phrs.2023.106845] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 06/28/2023] [Accepted: 06/29/2023] [Indexed: 07/14/2023]
Abstract
The promise of nicotinic receptors as a therapeutic target has yet to be fully realized, despite solid data supporting their involvement in neurological and neuropsychiatric diseases. The reasons for this are likely complex and manifold, having to do with the widespread action of the cholinergic system and the biophysical mechanism of action of nicotinic receptors leading to fast desensitization and down-regulation. Conventional drug development strategies tend to focus on receptor subtype-specific action of candidate therapeutics, although the broad agonist, nicotine, is being explored in the clinic. The potential negative effects of nicotine make the search for alternate strategies warranted. Prototoxins are a promising yet little-explored avenue of nicotinic receptor drug development. Nicotinic receptors in the brain belong to a complex of proteins, including those that bind to the extracellular face of the receptor, as well as chaperones that bind the intracellular domain, etc. Lynx prototoxins have allosteric modularity effects on receptor function and number and have been implicated in complex in vivo processes such as neuroplasticity, learning, and memory. Their mechanism of action and binding specificity on sets of nAChR subtypes present intriguing possibilities for more efficacious and nuanced therapeutic targeting than nicotinic receptor subtypes alone. An allosteric drug may restrict its actions to physiologically relevant time points, which tend to be correlated with salient events which would be encoded into long-term memory storage. Rather than blanketing the brain with a steady and prolonged elevation of agonist, an allosteric nAChR compound could avoid side effects and loss of efficacy over time. This review details the potential strengths and challenges of prototoxin proteins as therapeutic targets, and some of the utility of such therapeutics based on the emerging understanding of cholinergic signaling in a growing number of complex neural processes.
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Affiliation(s)
- Talulla B Palumbo
- Department of Biological Sciences, Lehigh University, 111 Research Dr., Iacocca Hall, B-217, Bethlehem PA, USA.
| | - Julie M Miwa
- Department of Biological Sciences, Lehigh University, 111 Research Dr., Iacocca Hall, B-217, Bethlehem PA, USA.
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2
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Cai W, Li L, Sang S, Pan X, Zhong C. Physiological Roles of β-amyloid in Regulating Synaptic Function: Implications for AD Pathophysiology. Neurosci Bull 2023; 39:1289-1308. [PMID: 36443453 PMCID: PMC10387033 DOI: 10.1007/s12264-022-00985-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 09/02/2022] [Indexed: 11/29/2022] Open
Abstract
The physiological functions of endogenous amyloid-β (Aβ), which plays important role in the pathology of Alzheimer's disease (AD), have not been paid enough attention. Here, we review the multiple physiological effects of Aβ, particularly in regulating synaptic transmission, and the possible mechanisms, in order to decipher the real characters of Aβ under both physiological and pathological conditions. Some worthy studies have shown that the deprivation of endogenous Aβ gives rise to synaptic dysfunction and cognitive deficiency, while the moderate elevation of this peptide enhances long term potentiation and leads to neuronal hyperexcitability. In this review, we provide a new view for understanding the role of Aβ in AD pathophysiology from the perspective of physiological meaning.
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Affiliation(s)
- Wenwen Cai
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Linxi Li
- Basic Medical College, Nanchang University, Nanchang, 330031, China
| | - Shaoming Sang
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Xiaoli Pan
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
| | - Chunjiu Zhong
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science & Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China.
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3
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Nicotine's effect on cognition, a friend or foe? Prog Neuropsychopharmacol Biol Psychiatry 2023; 124:110723. [PMID: 36736944 DOI: 10.1016/j.pnpbp.2023.110723] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 01/27/2023] [Accepted: 01/29/2023] [Indexed: 02/04/2023]
Abstract
Tobacco smoking is a preventable cause of morbidity and mortality throughout the world. Smoking comes in form of absorption of many compounds, among which nicotine is the main psychoactive component of tobacco and its positive and negative reinforcement effects are proposed to be the key mechanism for the initiation and maintenance of smoking. Growing evidence suggests that the cognitive enhancement effects of nicotine may also contribute to the difficulty of quitting smoking, especially in individuals with psychiatric disorders. In this review, we first introduce the beneficial effect of nicotine on cognition including attention, short-term memory and long-term memory. We next summarize the beneficial effect of nicotine on cognition under pathological conditions, including Alzheimer's disease, Parkinson's disease, Schizophrenia, Stress-induced Anxiety, Depression, and drug-induced memory impairment. The possible mechanism underlying nicotine's effect is also explored. Finally, nicotine's detrimental effect on cognition is discussed, including in the prenatal and adolescent periods, and high-dose nicotine- and withdrawal-induced memory impairment is emphasized. Therefore, nicotine serves as both a friend and foe. Nicotine-derived compounds could be a promising strategy to alleviate neurological disease-associated cognitive deficit, however, due to nicotine's detrimental effect, continued educational programs and public awareness campaigns are needed to reduce tobacco use among pregnant women and smoking should be quitted even if it is e-cigarette, especially for the adolescents.
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4
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Terry AV, Jones K, Bertrand D. Nicotinic acetylcholine receptors in neurological and psychiatric diseases. Pharmacol Res 2023; 191:106764. [PMID: 37044234 DOI: 10.1016/j.phrs.2023.106764] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/30/2023] [Accepted: 04/07/2023] [Indexed: 04/14/2023]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels that are widely distributed both pre- and post-synaptically in the mammalian brain. By modulating cation flux across cell membranes, neuronal nAChRs regulate neuronal excitability and the release of a variety of neurotransmitters to influence multiple physiologic and behavioral processes including synaptic plasticity, motor function, attention, learning and memory. Abnormalities of neuronal nAChRs have been implicated in the pathophysiology of neurologic disorders including Alzheimer's disease, Parkinson's disease, epilepsy, and Tourette´s syndrome, as well as psychiatric disorders including schizophrenia, depression, and anxiety. The potential role of nAChRs in a particular illness may be indicated by alterations in the expression of nAChRs in relevant brain regions, genetic variability in the genes encoding for nAChR subunit proteins, and/or clinical or preclinical observations where specific ligands showed a therapeutic effect. Over the past 25 years, extensive preclinical and some early clinical evidence suggested that ligands at nAChRs might have therapeutic potential for neurologic and psychiatric disorders. However, to date the only approved indications for nAChR ligands are smoking cessation and the treatment of dry eye disease. It has been argued that progress in nAChR drug discovery has been limited by translational gaps between the preclinical models and the human disease as well as unresolved questions regarding the pharmacological goal (i.e., agonism, antagonism or receptor desensitization) depending on the disease.
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Affiliation(s)
- Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, Georgia, 30912.
| | - Keri Jones
- Educational Innovation Institute, Medical College of Georgia at Augusta University, Augusta, Georgia, 30912
| | - Daniel Bertrand
- HiQScreen Sàrl, 6, rte de Compois, 1222 Vésenaz, Geneva, Switzerland
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Vilella A, Romoli B, Bodria M, Pons S, Maskos U, Zoli M. Evidence for a protective effect of the loss of α4-containing nicotinic acetylcholine receptors on Aβ-related neuropathology in Tg2576 mice. Front Neurosci 2023; 17:1097857. [PMID: 37113156 PMCID: PMC10126303 DOI: 10.3389/fnins.2023.1097857] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 03/15/2023] [Indexed: 04/29/2023] Open
Abstract
Introduction Loss of cholinergic neurons as well as α4β2* (* = containing) nicotinic acetylcholine receptors (nAChRs) is a prominent feature of Alzheimer's disease (AD). Specifically, amyloid β (Aβ), the principal pathogenic factor of AD, is a high affinity ligand for nAChRs. Yet, the pathophysiological role of nAChRs in AD is not well established. Methods In the present study, we have investigated the effects of the loss of α4* nAChRs on the histological alterations of the Tg2576 mouse model of AD (APPswe) crossing hemizygous APPswe mice with mice carrying the genetic inactivation of α4 nAChR subunit (α4KO). Results A global decrease in Aβ plaque load was observed in the forebrain of APPswe/α4KO mice in comparison with APPswe mice, that was particularly marked in neocortex of 15 month-old mice. At the same age, several alterations in synaptophysin immunoreactivity were observed in cortico-hippocampal regions of APPswe mice that were partially counteracted by α4KO. The analysis of the immunoreactivity of specific astroglia (glial fibrillary acidic protein, GFAP) and microglia (ionized calcium-binding adapter molecule, Iba1) markers showed an increase in the number as well as in the area occupied by these cells in APPswe mice that were partially counteracted by α4KO. Conclusion Overall, the present histological study points to a detrimental role of α4* nAChRs that may be specific for Aβ-related neuropathology.
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Affiliation(s)
- Antonietta Vilella
- Department of Biomedical, Metabolic and Neural Sciences, Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
- *Correspondence: Antonietta Vilella,
| | - Benedetto Romoli
- Department of Biomedical, Metabolic and Neural Sciences, Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
| | - Martina Bodria
- Department of Biomedical, Metabolic and Neural Sciences, Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
| | - Stéphanie Pons
- Institut Pasteur, Université Paris Cité, Neurobiologie Intégrative des Systèmes Cholinergiques, CNRS UMR 3571, Département de Neuroscience, Paris, France
| | - Uwe Maskos
- Institut Pasteur, Université Paris Cité, Neurobiologie Intégrative des Systèmes Cholinergiques, CNRS UMR 3571, Département de Neuroscience, Paris, France
| | - Michele Zoli
- Department of Biomedical, Metabolic and Neural Sciences, Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
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Keeley RJ, Prillaman ME, Scarlata M, Vrana A, Tsai PJ, Gomez JL, Bonaventura J, Lu H, Michaelides M, Stein EA. Adolescent nicotine administration increases nicotinic acetylcholine receptor binding and functional connectivity in specific cortico-striatal-thalamic circuits. Brain Commun 2022; 4:fcac291. [PMID: 36440101 PMCID: PMC9683397 DOI: 10.1093/braincomms/fcac291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 07/05/2022] [Accepted: 11/17/2022] [Indexed: 11/28/2023] Open
Abstract
Nicotine exposure is associated with regional changes in brain nicotinic acetylcholine receptors subtype expression patterns as a function of dose and age at the time of exposure. Moreover, nicotine dependence is associated with changes in brain circuit functional connectivity, but the relationship between such connectivity and concomitant regional distribution changes in nicotinic acetylcholine receptor subtypes following nicotine exposure is not understood. Although smoking typically begins in adolescence, developmental changes in brain circuits and nicotinic acetylcholine receptors following chronic nicotine exposure remain minimally investigated. Here, we combined in vitro nicotinic acetylcholine receptor autoradiography with resting state functional magnetic resonance imaging to measure changes in [3H]nicotine binding and α4ß2 subtype nicotinic acetylcholine receptor binding and circuit connectivity across the brain in adolescent (postnatal Day 33) and adult (postnatal Day 68) rats exposed to 6 weeks of nicotine administration (0, 1.2 and 4.8 mg/kg/day). Chronic nicotine exposure increased nicotinic acetylcholine receptor levels and induced discrete, developmental stage changes in regional nicotinic acetylcholine receptor subtype distribution. These effects were most pronounced in striatal, thalamic and cortical regions when nicotine was administered during adolescence but not in adults. Using these regional receptor changes as seeds, resting state functional magnetic resonance imaging identified dysregulations in cortico-striatal-thalamic-cortical circuits that were also dysregulated following adolescent nicotine exposure. Thus, nicotine-induced increases in cortical, striatal and thalamic nicotinic acetylcholine receptors during adolescence modifies processing and brain circuits within cortico-striatal-thalamic-cortical loops, which are known to be crucial for multisensory integration, action selection and motor output, and may alter the developmental trajectory of the adolescent brain. This unique multimodal study significantly advances our understanding of nicotine dependence and its effects on the adolescent brain.
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Affiliation(s)
- Robin J Keeley
- National Institute on Drug Abuse, Intramural Research Program (NIDA-IRP), National Institutes of Health, Baltimore, MD 21224, USA
| | - McKenzie E Prillaman
- National Institute on Drug Abuse, Intramural Research Program (NIDA-IRP), National Institutes of Health, Baltimore, MD 21224, USA
| | - Miranda Scarlata
- National Institute on Drug Abuse, Intramural Research Program (NIDA-IRP), National Institutes of Health, Baltimore, MD 21224, USA
| | - Antonia Vrana
- National Institute on Drug Abuse, Intramural Research Program (NIDA-IRP), National Institutes of Health, Baltimore, MD 21224, USA
| | - Pei-Jung Tsai
- National Institute on Drug Abuse, Intramural Research Program (NIDA-IRP), National Institutes of Health, Baltimore, MD 21224, USA
| | - Juan L Gomez
- National Institute on Drug Abuse, Intramural Research Program (NIDA-IRP), National Institutes of Health, Baltimore, MD 21224, USA
| | - Jordi Bonaventura
- National Institute on Drug Abuse, Intramural Research Program (NIDA-IRP), National Institutes of Health, Baltimore, MD 21224, USA
- Departament de Patologia Terapèutica Experimental, Institut de Neurociènes, Universitat de Barcelona, Gran Via de les Corts Catalanes, 585, 08007 Barcelona, Spain
| | - Hanbing Lu
- National Institute on Drug Abuse, Intramural Research Program (NIDA-IRP), National Institutes of Health, Baltimore, MD 21224, USA
| | - Michael Michaelides
- National Institute on Drug Abuse, Intramural Research Program (NIDA-IRP), National Institutes of Health, Baltimore, MD 21224, USA
| | - Elliot A Stein
- National Institute on Drug Abuse, Intramural Research Program (NIDA-IRP), National Institutes of Health, Baltimore, MD 21224, USA
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7
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Characterization of social behavior in young and middle-aged ChAT-IRES-Cre mouse. PLoS One 2022; 17:e0272141. [PMID: 35925937 PMCID: PMC9352053 DOI: 10.1371/journal.pone.0272141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 07/13/2022] [Indexed: 11/19/2022] Open
Abstract
The cholinergic system is an important modulator of brain processes. It contributes to the regulation of several cognitive functions and emotional states, hence altering behaviors. Previous works showed that cholinergic (nicotinic) receptors of the prefrontal cortex are needed for adapted social behaviors. However, these data were obtained in mutant mice that also present alterations of several neurotransmitter systems, in addition to the cholinergic system. ChAT-IRES-Cre mice, that express the Cre recombinase specifically in cholinergic neurons, are useful tools to investigate the role of the cholinergic circuits in behavior. However, their own behavioral phenotype has not yet been fully characterized, in particular social behavior. In addition, the consequences of aging on the cholinergic system of ChAT-IRES-Cre mice has never been studied, despite the fact that aging is known to compromise the cholinergic system efficiency. The aim of the current study was thus to characterize the social phenotype of ChAT-IRES-Cre mice both at young (2–3 months) and middle (10–11 months) ages. Our results reveal an alteration of the cholinergic system, evidenced by a decrease of ChAT, CHT and VAChT gene expression in the striatum of the mice, that was accompanied by mild social disturbances and a tendency towards anxiety. Aging decreased social dominance, without being amplified by the cholinergic alterations. Altogether, this study shows that ChAT-IRES-Cre mice are useful models for studying the cholinergic system‘s role in social behavior using appropriate modulating technics (optogenetic or DREADD).
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8
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Zhang L, Chen S, Sun Y. Mechanism and Prevention of Spiral Ganglion Neuron Degeneration in the Cochlea. Front Cell Neurosci 2022; 15:814891. [PMID: 35069120 PMCID: PMC8766678 DOI: 10.3389/fncel.2021.814891] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 12/09/2021] [Indexed: 12/14/2022] Open
Abstract
Sensorineural hearing loss (SNHL) is one of the most prevalent sensory deficits in humans, and approximately 360 million people worldwide are affected. The current treatment option for severe to profound hearing loss is cochlear implantation (CI), but its treatment efficacy is related to the survival of spiral ganglion neurons (SGNs). SGNs are the primary sensory neurons, transmitting complex acoustic information from hair cells to second-order sensory neurons in the cochlear nucleus. In mammals, SGNs have very limited regeneration ability, and SGN loss causes irreversible hearing loss. In most cases of SNHL, SGN damage is the dominant pathogenesis, and it could be caused by noise exposure, ototoxic drugs, hereditary defects, presbycusis, etc. Tremendous efforts have been made to identify novel treatments to prevent or reverse the damage to SGNs, including gene therapy and stem cell therapy. This review summarizes the major causes and the corresponding mechanisms of SGN loss and the current protection strategies, especially gene therapy and stem cell therapy, to promote the development of new therapeutic methods.
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Affiliation(s)
- Li Zhang
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Sen Chen
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yu Sun
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Institute of Otorhinolaryngology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- *Correspondence: Yu Sun,
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Ogawa B, Nakanishi Y, Wakamatsu M, Takahashi Y, Shibutani M. Repeated administration of acrylamide for 28 days reduces late-stage progenitor cells and immature granule cells accompanying impaired neurite outgrowth in the adult hippocampal neurogenesis in young-adult rats. J Toxicol Sci 2022; 47:467-482. [DOI: 10.2131/jts.47.467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Bunichiro Ogawa
- Drug Safety and Pharmacokinetics Laboratories, Taisho Pharmaceutical Co., Ltd
| | - Yutaka Nakanishi
- Drug Safety and Pharmacokinetics Laboratories, Taisho Pharmaceutical Co., Ltd
| | - Masaki Wakamatsu
- Drug Safety and Pharmacokinetics Laboratories, Taisho Pharmaceutical Co., Ltd
| | - Yasunori Takahashi
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology
| | - Makoto Shibutani
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology
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10
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Luijerink LLM, Vivekanandarajah A, Waters KA, Machaalani R. The α7 and β2 nicotinic acetylcholine receptor subunits regulate apoptosis in the infant hippocampus, and in sudden infant death syndrome (SIDS). Apoptosis 2021; 25:574-589. [PMID: 32577853 DOI: 10.1007/s10495-020-01618-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Apoptosis is increased in the hippocampus of infants who died of sudden infant death syndrome (SIDS), yet it is not known via which mechanism this has occurred. Following existing support for a role of the α7 and β2 nicotinic acetylcholine receptor (nAChR) subunits in apoptotic regulation, we aimed to determine whether these subunits are altered in the SIDS hippocampus and if they are correlated with cell death markers of active caspase-3 (Casp-3) and TUNEL. Further analyses were run according to the presence of major SIDS risk factors related to hypoxia (bed-sharing and prone sleeping), infection (presence of an upper respiratory tract infection (URTI)), cigarette smoke exposure and gender. Immunohistochemical expression of the markers was studied in 4 regions of the hippocampus (Cornu Ammonis (CA)1, CA2, CA3, CA4) and subiculum amongst 52 infants (aged 1-7 months) who died suddenly and unexpectedly (SUDI) and for whom the cause of death was explained (eSUDI; n = 9), or not and characterised as SIDS I (n = 8) and SIDS II (n = 35) according to the San Diego diagnostic criteria. Results showed that SIDS II infants had widespread increases in TUNEL compared with eSUDI and SIDS I infants, as well as increased α7 and Casp-3 in CA2 compared to eSUDI infants, although these changes were predominant amongst infants who did not bed-share. Cigarette smoke exposure had minimal effects on the markers, while an URTI was associated with changes in all markers (after accounting for bed-sharing). Our findings support the role of nAChRs in regulating apoptosis in the SIDS hippocampus, and highlight the need for separate analysis according to risk factors.
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Affiliation(s)
- L L M Luijerink
- Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Medical Foundation Building K25, Sydney, NSW, 2006, Australia
| | - A Vivekanandarajah
- Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Medical Foundation Building K25, Sydney, NSW, 2006, Australia
| | - K A Waters
- Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Medical Foundation Building K25, Sydney, NSW, 2006, Australia.,The Children's Hospital at Westmead, Westmead, NSW, 2146, Australia
| | - R Machaalani
- Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Medical Foundation Building K25, Sydney, NSW, 2006, Australia. .,The Children's Hospital at Westmead, Westmead, NSW, 2146, Australia.
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11
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Sun P, Liu DG, Ye XM. Nicotinic Acetylcholine Receptor α7 Subunit Is an Essential Regulator of Seizure Susceptibility. Front Neurol 2021; 12:656752. [PMID: 33912128 PMCID: PMC8072353 DOI: 10.3389/fneur.2021.656752] [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: 01/21/2021] [Accepted: 03/12/2021] [Indexed: 01/16/2023] Open
Abstract
A large body of data has confirmed that α7 nicotinic acetylcholine receptors (nAChRs) play a pivotal role in cognition, memory, and other neuropsychiatric diseases, but their effect on seizure susceptibility in C57BL/6 wild-type mice is not fully understood. Here, we showed that decreased activity of α7 nAChRs could increase the excitability of CA1 pyramidal neurons and shorten the onset time of epilepsy in pilocarpine-induced mouse models. However, compared with the control group, there was no apparent effect of increasing the activity of α7 nAChRs. Moreover, the expression of α7 nAChRs is downregulated in human epileptogenic tissues. Taken together, our findings indicate that α7 nAChR is an essential regulator of seizure susceptibility.
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Affiliation(s)
- Peng Sun
- Rehabilitation & Sports Medicine Research Institute of Zhejiang Province, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Da-Gang Liu
- Department of Neurosurgery Medicine, Weihai Central Hospital, Weihai, China
| | - Xiang-Ming Ye
- Rehabilitation & Sports Medicine Research Institute of Zhejiang Province, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
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12
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Implications of Oligomeric Amyloid-Beta (oAβ 42) Signaling through α7β2-Nicotinic Acetylcholine Receptors (nAChRs) on Basal Forebrain Cholinergic Neuronal Intrinsic Excitability and Cognitive Decline. J Neurosci 2020; 41:555-575. [PMID: 33239400 DOI: 10.1523/jneurosci.0876-20.2020] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 11/03/2020] [Accepted: 11/15/2020] [Indexed: 01/08/2023] Open
Abstract
Neuronal and network-level hyperexcitability is commonly associated with increased levels of amyloid-β (Aβ) and contribute to cognitive deficits associated with Alzheimer's disease (AD). However, the mechanistic complexity underlying the selective loss of basal forebrain cholinergic neurons (BFCNs), a well-recognized characteristic of AD, remains poorly understood. In this study, we tested the hypothesis that the oligomeric form of amyloid-β (oAβ42), interacting with α7-containing nicotinic acetylcholine receptor (nAChR) subtypes, leads to subnucleus-specific alterations in BFCN excitability and impaired cognition. We used single-channel electrophysiology to show that oAβ42 activates both homomeric α7- and heteromeric α7β2-nAChR subtypes while preferentially enhancing α7β2-nAChR open-dwell times. Organotypic slice cultures were prepared from male and female ChAT-EGFP mice, and current-clamp recordings obtained from BFCNs chronically exposed to pathophysiologically relevant level of oAβ42 showed enhanced neuronal intrinsic excitability and action potential firing rates. These resulted from a reduction in action potential afterhyperpolarization and alterations in the maximal rates of voltage change during spike depolarization and repolarization. These effects were observed in BFCNs from the medial septum diagonal band and horizontal diagonal band, but not the nucleus basalis. Last, aged male and female APP/PS1 transgenic mice, genetically null for the β2 nAChR subunit gene, showed improved spatial reference memory compared with APP/PS1 aged-matched littermates. Combined, these data provide a molecular mechanism supporting a role for α7β2-nAChR in mediating the effects of oAβ42 on excitability of specific populations of cholinergic neurons and provide a framework for understanding the role of α7β2-nAChR in oAβ42-induced cognitive decline.
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13
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Gamage R, Wagnon I, Rossetti I, Childs R, Niedermayer G, Chesworth R, Gyengesi E. Cholinergic Modulation of Glial Function During Aging and Chronic Neuroinflammation. Front Cell Neurosci 2020; 14:577912. [PMID: 33192323 PMCID: PMC7594524 DOI: 10.3389/fncel.2020.577912] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/07/2020] [Indexed: 12/12/2022] Open
Abstract
Aging is a complex biological process that increases the risk of age-related cognitive degenerative diseases such as dementia, including Alzheimer’s disease (AD), Lewy Body Dementia (LBD), and mild cognitive impairment (MCI). Even non-pathological aging of the brain can involve chronic oxidative and inflammatory stress, which disrupts the communication and balance between the brain and the immune system. There has been an increasingly strong connection found between chronic neuroinflammation and impaired memory, especially in AD. While microglia and astrocytes, the resident immune cells of the central nervous system (CNS), exerting beneficial effects during the acute inflammatory phase, during chronic neuroinflammation they can become more detrimental. Central cholinergic circuits are involved in maintaining normal cognitive function and regulating signaling within the entire cerebral cortex. While neuronal-glial cholinergic signaling is anti-inflammatory and anti-oxidative, central cholinergic neuronal degeneration is implicated in impaired learning, memory sleep regulation, and attention. Although there is evidence of cholinergic involvement in memory, fewer studies have linked the cholinergic anti-inflammatory and anti-oxidant pathways to memory processes during development, normal aging, and disease states. This review will summarize the current knowledge of cholinergic effects on microglia and astroglia, and their role in both anti-inflammatory and anti-oxidant mechanisms, concerning normal aging and chronic neuroinflammation. We provided details on how stimulation of α7 nicotinic acetylcholine (α7nACh) receptors can be neuroprotective by increasing amyloid-β phagocytosis, decreasing inflammation and reducing oxidative stress by promoting the nuclear factor erythroid 2-related factor 2 (Nrf2) pathways and decreasing the release of pro-inflammatory cytokines. There is also evidence for astroglial α7nACh receptor stimulation mediating anti-inflammatory and antioxidant effects by inhibiting the nuclear factor-κB (NF-κB) pathway and activating the Nrf2 pathway respectively. We conclude that targeting cholinergic glial interactions between neurons and glial cells via α7nACh receptors could regulate neuroinflammation and oxidative stress, relevant to the treatment of several neurodegenerative diseases.
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Affiliation(s)
- Rashmi Gamage
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Ingrid Wagnon
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Ilaria Rossetti
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Ryan Childs
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Garry Niedermayer
- School of Science, Western Sydney University, Penrith, NSW, Australia
| | - Rose Chesworth
- School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Erika Gyengesi
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
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14
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Richardson BD, Sottile SY, Caspary DM. Mechanisms of GABAergic and cholinergic neurotransmission in auditory thalamus: Impact of aging. Hear Res 2020; 402:108003. [PMID: 32703637 DOI: 10.1016/j.heares.2020.108003] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 05/15/2020] [Accepted: 05/23/2020] [Indexed: 12/18/2022]
Abstract
Age-related hearing loss is a complex disorder affecting a majority of the elderly population. As people age, speech understanding becomes a challenge especially in complex acoustic settings and negatively impacts the ability to accurately analyze the auditory scene. This is in part due to an inability to focus auditory attention on a particular stimulus source while simultaneously filtering out other sound stimuli. The present review examines the impact of aging on two neurotransmitter systems involved in accurate temporal processing and auditory gating in auditory thalamus (medial geniculate body; MGB), a critical brain region involved in the coding and filtering of auditory information. The inhibitory neurotransmitter GABA and its synaptic receptors (GABAARs) are key to maintaining accurate temporal coding of complex sounds, such as speech, throughout the central auditory system. In the MGB, synaptic and extrasynaptic GABAARs mediate fast phasic and slow tonic inhibition respectively, which in turn regulate MGB neuron excitability, firing modes, and engage thalamocortical oscillations that shape coding and gating of acoustic content. Acoustic coding properties of MGB neurons are further modulated through activation of tegmental cholinergic afferents that project to MGB to potentially modulate attention and help to disambiguate difficult to understand or novel sounds. Acetylcholine is released onto MGB neurons and presynaptic terminals in MGB activating neuronal nicotinic and muscarinic acetylcholine receptors (nAChRs, mAChRs) at a subset of MGB afferents to optimize top-down and bottom-up information flow. Both GABAergic and cholinergic neurotransmission is significantly altered with aging and this review will detail how age-related changes in these circuits within the MGB may impact coding of acoustic stimuli.
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Affiliation(s)
- B D Richardson
- WWAMI Medical Education, University of Idaho, Moscow, ID, 83844, USA; Biological Engineering, University of Idaho, Moscow, ID, 83844, USA
| | - S Y Sottile
- Center for Clinical Research Southern Illinois University - School of Medicine, Springfield, IL, 62702, USA
| | - D M Caspary
- Department of Pharmacology Southern Illinois University - School of Medicine, Springfield, IL, 62702, USA.
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15
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Modulation of cholinergic activity through lynx prototoxins: Implications for cognition and anxiety regulation. Neuropharmacology 2020; 174:108071. [PMID: 32298703 PMCID: PMC7785133 DOI: 10.1016/j.neuropharm.2020.108071] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 03/16/2020] [Accepted: 03/24/2020] [Indexed: 02/08/2023]
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16
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Kynurenine Pathway as a New Target of Cognitive Impairment Induced by Lead Toxicity During the Lactation. Sci Rep 2020; 10:3184. [PMID: 32081969 PMCID: PMC7035386 DOI: 10.1038/s41598-020-60159-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 02/07/2020] [Indexed: 12/31/2022] Open
Abstract
The immature brain is especially vulnerable to lead (Pb2+) toxicity, which is considered an environmental neurotoxin. Pb2+ exposure during development compromises the cognitive and behavioral attributes which persist even later in adulthood, but the mechanisms involved in this effect are still unknown. On the other hand, the kynurenine pathway metabolites are modulators of different receptors and neurotransmitters related to cognition; specifically, high kynurenic acid levels has been involved with cognitive impairment, including deficits in spatial working memory and attention process. The aim of this study was to evaluate the relationship between the neurocognitive impairment induced by Pb2+ toxicity and the kynurenine pathway. The dams were divided in control group and Pb2+ group, which were given tap water or 500 ppm of lead acetate in drinking water ad libitum, respectively, from 0 to 23 postnatal day (PND). The poison was withdrawn, and tap water was given until 60 PND of the progeny. The locomotor activity in open field, redox environment, cellular function, kynurenic acid (KYNA) and 3-hydroxykynurenine (3-HK) levels as well as kynurenine aminotransferase (KAT) and kynurenine monooxygenase (KMO) activities were evaluated at both 23 and 60 PND. Additionally, learning and memory through buried food location test and expression of KAT and KMO, and cellular damage were evaluated at 60 PND. Pb2+ group showed redox environment alterations, cellular dysfunction and KYNA and 3-HK levels increased. No changes were observed in KAT activity. KMO activity increased at 23 PND and decreased at 60 PND. No changes in KAT and KMO expression in control and Pb2+ group were observed, however the number of positive cells expressing KMO and KAT increased in relation to control, which correlated with the loss of neuronal population. Cognitive impairment was observed in Pb2+ group which was correlated with KYNA levels. These results suggest that the increase in KYNA levels could be a mechanism by which Pb2+ induces cognitive impairment in adult mice, hence the modulation of kynurenine pathway represents a potential target to improve behavioural alterations produced by this environmental toxin.
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17
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Lykhmus O, Koval L, Voytenko L, Uspenska K, Komisarenko S, Deryabina O, Shuvalova N, Kordium V, Ustymenko A, Kyryk V, Skok M. Intravenously Injected Mesenchymal Stem Cells Penetrate the Brain and Treat Inflammation-Induced Brain Damage and Memory Impairment in Mice. Front Pharmacol 2019; 10:355. [PMID: 31057400 PMCID: PMC6479176 DOI: 10.3389/fphar.2019.00355] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/21/2019] [Indexed: 12/11/2022] Open
Abstract
Neuroinflammation is regarded as one of the pathogenic factors of Alzheimer disease (AD). Previously, we showed that mice regularly injected with bacterial lipopolysaccharide (LPS) possessed the AD-like symptoms like episodic memory decline, elevated amounts of amyloid beta (Aβ) peptide (1-42), and decreased levels of nicotinic acetylcholine receptors (nAChRs) in the brain. The use of mesenchymal stem cells (MSCs), which can differentiate into multiple cell types, including neurons, is an attractive idea of regenerative medicine, in particular, for neurodegenerative disorders like AD. In the present study, we aimed to investigate whether pathogenic effect of LPS on the brain and behavior of mice can be prevented or treated by injection of MSCs or MSC-produced soluble factors. Fluorescently-labeled MSCs, injected intravenously, were found in the brain blood vessels of LPS-treated mice. Mice co-injected with LPS and MSCs did not demonstrate episodic memory impairment, Aβ (1-42) accumulation, and nAChR decrease in the brain and brain mitochondria. Their mitochondria released less cytochrome c under the effect of Ca2+ compared to mitochondria of LPS-only-treated mice. Moreover, MSCs could reverse the pathogenic symptoms developed 3 weeks after LPS injection. Cultured MSCs produced IL-6 in response to LPS and MSCs effect in vivo was accompanied by additional stimulation of both micro- and macroglia. Xenogeneic (human) MSCs were almost as efficient as allogeneic (mouse) ones and regular injections of human MSC-conditioned medium also produced positive effect. These data allow suggesting MSCs as a potential therapeutic tool to cure neuroinflammation-related cognitive pathology.
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Affiliation(s)
- Olena Lykhmus
- Laboratory of Cell Receptors Immunology, Palladin Institute of Biochemistry NAS, Kyiv, Ukraine
| | - Lyudmyla Koval
- Laboratory of Cell Receptors Immunology, Palladin Institute of Biochemistry NAS, Kyiv, Ukraine
| | - Larysa Voytenko
- Laboratory of Cell Receptors Immunology, Palladin Institute of Biochemistry NAS, Kyiv, Ukraine
| | - Kateryna Uspenska
- Laboratory of Cell Receptors Immunology, Palladin Institute of Biochemistry NAS, Kyiv, Ukraine
| | - Serhiy Komisarenko
- Laboratory of Cell Receptors Immunology, Palladin Institute of Biochemistry NAS, Kyiv, Ukraine
| | - Olena Deryabina
- Department of Gene Technologies, State Institute of Genetic and Regenerative Medicine NAMS, Kyiv, Ukraine
| | - Nadia Shuvalova
- Department of Gene Technologies, State Institute of Genetic and Regenerative Medicine NAMS, Kyiv, Ukraine
| | - Vitalii Kordium
- Department of Gene Technologies, State Institute of Genetic and Regenerative Medicine NAMS, Kyiv, Ukraine.,Department of Cell Regulatory Mechanisms, Institute of Molecular Biology and Genetics NAS, Kyiv, Ukraine
| | - Alina Ustymenko
- Department of Gene Technologies, State Institute of Genetic and Regenerative Medicine NAMS, Kyiv, Ukraine
| | - Vitalii Kyryk
- Department of Gene Technologies, State Institute of Genetic and Regenerative Medicine NAMS, Kyiv, Ukraine
| | - Maryna Skok
- Laboratory of Cell Receptors Immunology, Palladin Institute of Biochemistry NAS, Kyiv, Ukraine
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18
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RETRACTED: Nicotinic acetylcholine receptor α7 subunit maybe a risk factor of seizure susceptibility. Neurosci Lett 2019; 704:15-20. [PMID: 30946925 DOI: 10.1016/j.neulet.2019.03.053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 03/03/2019] [Accepted: 03/30/2019] [Indexed: 01/16/2023]
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19
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Vivekanandarajah A, Waters KA, Machaalani R. Cigarette smoke exposure effects on the brainstem expression of nicotinic acetylcholine receptors (nAChRs), and on cardiac, respiratory and sleep physiologies. Respir Physiol Neurobiol 2018; 259:1-15. [PMID: 30031221 DOI: 10.1016/j.resp.2018.07.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/16/2018] [Accepted: 07/17/2018] [Indexed: 12/15/2022]
Abstract
Cigarette smoking during pregnancy is the largest modifiable risk factor for adverse outcomes in the infant. Investigations have focused on the psychoactive component of cigarettes, nicotine. One proposed mechanism leading to adverse effects is the interaction between nicotine and its nicotinic acetylcholine receptors (nAChRs). Much data has been generated over the past three decades on the effects of cigarette smoke exposure (CSE) on the expression of the nAChRs in the brainstem and physiological parameters related to cardiac, respiration and sleep, in the offspring of smoking mothers and animal models of nicotine exposure. This review summarises this data and discusses the main findings, highlighting that findings in animal models closely correlate with those from human studies, and that the major brainstem sites where the expression level for the nAChRs are consistently affected include those that play vital roles in cardiorespiration (hypoglossal nucleus, dorsal motor nucleus of the vagus, nucleus of the solitary tract), chemosensation (nucleus of the solitary tract, arcuate nucleus) and arousal (rostral mesopontine sites such as the locus coeruleus and nucleus pontis oralis). These findings provide evidence for the adverse effects of CSE during and after pregnancy to the infant and the need to continue with the health campaign advising against CSE.
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Affiliation(s)
- Arunnjah Vivekanandarajah
- SIDS and Sleep Apnea Laboratory, Sydney Medical School, Medical Foundation Building K25, University of Sydney, NSW 2006, Australia.
| | - Karen A Waters
- SIDS and Sleep Apnea Laboratory, Sydney Medical School, Medical Foundation Building K25, University of Sydney, NSW 2006, Australia; Discipline of Paediatrics and Child Health, Children's Hospital Westmead, NSW, Australia
| | - Rita Machaalani
- SIDS and Sleep Apnea Laboratory, Sydney Medical School, Medical Foundation Building K25, University of Sydney, NSW 2006, Australia; Discipline of Paediatrics and Child Health, Children's Hospital Westmead, NSW, Australia
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20
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Relevance of Alternative Routes of Kynurenic Acid Production in the Brain. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:5272741. [PMID: 29977455 PMCID: PMC5994304 DOI: 10.1155/2018/5272741] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/24/2018] [Indexed: 01/24/2023]
Abstract
The catabolism of tryptophan has gained great importance in recent years due to the fact that the metabolites produced during this process, with neuroactive and redox properties, are involved in physiological and pathological events. One of these metabolites is kynurenic acid (KYNA), which is considered as a neuromodulator since it can interact with NMDA, nicotinic, and GPR35 receptors among others, modulating the release of neurotransmitters as glutamate, dopamine, and acetylcholine. Kynureninate production is attributed to kynurenine aminotransferases. However, in some physiological and pathological conditions, its high production cannot be explained just with kynurenine aminotransferases. This review focuses on the alternative mechanism whereby KYNA can be produced, either from D-amino acids or by means of other enzymes as D-amino acid oxidase or by the participation of free radicals. It is important to mention that an increase in KYNA levels in processes as brain development, aging, neurodegenerative diseases, and psychiatric disorders, which share common factors as oxidative stress, inflammation, immune response activation, and participation of gut microbiota that can also be related with the alternative routes of KYNA production, has been observed.
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21
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Kolisnyk B, Al-Onaizi M, Soreq L, Barbash S, Bekenstein U, Haberman N, Hanin G, Kish MT, Souza da Silva J, Fahnestock M, Ule J, Soreq H, Prado VF, Prado MAM. Cholinergic Surveillance over Hippocampal RNA Metabolism and Alzheimer's-Like Pathology. Cereb Cortex 2018; 27:3553-3567. [PMID: 27312991 DOI: 10.1093/cercor/bhw177] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The relationship between long-term cholinergic dysfunction and risk of developing dementia is poorly understood. Here we used mice with deletion of the vesicular acetylcholine transporter (VAChT) in the forebrain to model cholinergic abnormalities observed in dementia. Whole-genome RNA sequencing of hippocampal samples revealed that cholinergic failure causes changes in RNA metabolism. Remarkably, key transcripts related to Alzheimer's disease are affected. BACE1, for instance, shows abnormal splicing caused by decreased expression of the splicing regulator hnRNPA2/B1. Resulting BACE1 overexpression leads to increased APP processing and accumulation of soluble Aβ1-42. This is accompanied by age-related increases in GSK3 activation, tau hyperphosphorylation, caspase-3 activation, decreased synaptic markers, increased neuronal death, and deteriorating cognition. Pharmacological inhibition of GSK3 hyperactivation reversed deficits in synaptic markers and tau hyperphosphorylation induced by cholinergic dysfunction, indicating a key role for GSK3 in some of these pathological changes. Interestingly, in human brains there was a high correlation between decreased levels of VAChT and hnRNPA2/B1 levels with increased tau hyperphosphorylation. These results suggest that changes in RNA processing caused by cholinergic loss can facilitate Alzheimer's-like pathology in mice, providing a mechanism by which decreased cholinergic tone may increase risk of dementia.
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Affiliation(s)
| | - Mohammed Al-Onaizi
- Robarts Research Institute.,Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A5K8
| | - Lilach Soreq
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Shahar Barbash
- The Edmond and Lily Safra Center for Brain Science and The Silberman Institute of Life Sciences, The Edmond J Safra Campus, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Uriya Bekenstein
- The Edmond and Lily Safra Center for Brain Science and The Silberman Institute of Life Sciences, The Edmond J Safra Campus, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Nejc Haberman
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Geula Hanin
- The Edmond and Lily Safra Center for Brain Science and The Silberman Institute of Life Sciences, The Edmond J Safra Campus, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Maxine T Kish
- Robarts Research Institute.,Department of Physiology and Pharmacology
| | | | - Margaret Fahnestock
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, CanadaL8S 4K1
| | - Jernej Ule
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Hermona Soreq
- The Edmond and Lily Safra Center for Brain Science and The Silberman Institute of Life Sciences, The Edmond J Safra Campus, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Vania F Prado
- Robarts Research Institute.,Graduate Program in Neuroscience.,Department of Physiology and Pharmacology.,Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A5K8
| | - Marco A M Prado
- Robarts Research Institute.,Graduate Program in Neuroscience.,Department of Physiology and Pharmacology.,Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A5K8
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22
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Al-Onaizi MA, Parfitt GM, Kolisnyk B, Law CSH, Guzman MS, Barros DM, Leung LS, Prado MAM, Prado VF. Regulation of Cognitive Processing by Hippocampal Cholinergic Tone. Cereb Cortex 2018; 27:1615-1628. [PMID: 26803167 DOI: 10.1093/cercor/bhv349] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cholinergic dysfunction has been associated with cognitive abnormalities in a variety of neurodegenerative and neuropsychiatric diseases. Here we tested how information processing is regulated by cholinergic tone in genetically modified mice targeting the vesicular acetylcholine transporter (VAChT), a protein required for acetylcholine release. We measured long-term potentiation of Schaffer collateral-CA1 synapses in vivo and assessed information processing by using a mouse touchscreen version of paired associates learning task (PAL). Acquisition of information in the mouse PAL task correlated to levels of hippocampal VAChT, suggesting a critical role for cholinergic tone. Accordingly, synaptic plasticity in the hippocampus in vivo was disturbed, but not completely abolished, by decreased hippocampal cholinergic signaling. Disrupted forebrain cholinergic signaling also affected working memory, a result reproduced by selectively decreasing VAChT in the hippocampus. In contrast, spatial memory was relatively preserved, whereas reversal spatial memory was sensitive to decreased hippocampal cholinergic signaling. This work provides a refined roadmap of how synaptically secreted acetylcholine influences distinct behaviors and suggests that distinct forms of cognitive processing may be regulated in different ways by cholinergic activity.
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Affiliation(s)
| | - Gustavo M Parfitt
- Robarts Research Institute.,Programa de Pós-graduação em Ciências Fisiológicas, Fisiologia Animal Comparada, Laboratório de Neurociências (FURG), Brazil
| | | | - Clayton S H Law
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, CanadaN6A5K8
| | - Monica S Guzman
- Robarts Research Institute.,Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A5K8
| | - Daniela Martí Barros
- Programa de Pós-graduação em Ciências Fisiológicas, Fisiologia Animal Comparada, Laboratório de Neurociências (FURG), Brazil
| | - L Stan Leung
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, CanadaN6A5K8
| | - Marco A M Prado
- Robarts Research Institute.,Department of Anatomy and Cell Biology.,Graduate Program in Neuroscience and.,Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A5K8
| | - Vania F Prado
- Robarts Research Institute.,Department of Anatomy and Cell Biology.,Graduate Program in Neuroscience and.,Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A5K8
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23
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Sottile SY, Ling L, Cox BC, Caspary DM. Impact of ageing on postsynaptic neuronal nicotinic neurotransmission in auditory thalamus. J Physiol 2017; 595:5375-5385. [PMID: 28585699 PMCID: PMC5538226 DOI: 10.1113/jp274467] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 05/24/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Neuronal nicotinic acetylcholine receptors (nAChRs) play a fundamental role in the attentional circuitry throughout the mammalian CNS. In the present study, we report a novel finding that ageing negatively impacts nAChR efficacy in auditory thalamus, and this is probably the result of a loss of nAChR density (Bmax ) and changes in the subunit composition of nAChRs. Our data support the hypothesis that age-related maladaptive changes involving nAChRs within thalamocortical circuits partially underpin the difficulty that elderly adults experience with respect to attending to speech and other salient acoustic signals. ABSTRACT The flow of auditory information through the medial geniculate body (MGB) is regulated, in part, by cholinergic projections from the pontomesencephalic tegmentum. The functional significance of these projections is not fully established, although they have been strongly implicated in the allocation of auditory attention. Using in vitro slice recordings, we have analysed postsynaptic function and pharmacology of neuronal nicotinic ACh receptors (nAChRs) in young adult and the aged rat MGB. We find that ACh produces significant excitatory postsynaptic actions on young MGB neurons, probably mediated by β2-containing heteromeric nAChRs. Radioligand binding studies show a significant age-related loss of heteromeric nAChR receptor number, which supports patch clamp data showing an age-related loss in ACh efficacy in evoking postsynaptic responses. Use of the β2-selective nAChR antagonist, dihydro-β-erythroidine, suggests that loss of cholinergic efficacy may also be the result of an age-related subunit switch from high affinity β2-containing nAChRs to low affinity β4-containing nAChRs, in addition to the loss of total nAChR number. This age-related nAChR dysfunction may partially underpin the attentional deficits that contribute to the loss of speech understanding in the elderly.
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Affiliation(s)
| | | | - Brandon C. Cox
- Department of Pharmacology
- Department of Surgery, Division of OtolaryngologySouthern Illinois University School of MedicineSpringfieldILUSA
| | - Donald M. Caspary
- Department of Pharmacology
- Department of Surgery, Division of OtolaryngologySouthern Illinois University School of MedicineSpringfieldILUSA
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24
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Wang ZJ, Deba F, Mohamed TS, Chiara DC, Ramos K, Hamouda AK. Unraveling amino acid residues critical for allosteric potentiation of (α4)3(β2)2-type nicotinic acetylcholine receptor responses. J Biol Chem 2017; 292:9988-10001. [PMID: 28446611 DOI: 10.1074/jbc.m116.771246] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 04/20/2017] [Indexed: 01/29/2023] Open
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) are promising drug targets to manage several neurological disorders and nicotine addiction. Growing evidence indicates that positive allosteric modulators of nAChRs improve pharmacological specificity by binding to unique sites present only in a subpopulation of nAChRs. Furthermore, nAChR positive allosteric modulators such as NS9283 and CMPI have been shown to potentiate responses of (α4)3(β2)2 but not (α4)2(β2)3 nAChR isoforms. This selective potentiation underlines that the α4:α4 interface, which is present only in the (α4)3(β2)2 nAChR, is an important and promising drug target. In this report we used site-directed mutagenesis to substitute specific amino acid residues and computational analyses to elucidate CMPI's binding mode at the α4:α4 subunit extracellular interface and identified a unique set of amino acid residues that determined its affinity. We found that amino acid residues α4Gly-41, α4Lys-64, and α4Thr-66 were critical for (α4)3(β2)2 nAChR potentiation by CMPI, but not by NS9283, whereas amino acid substitution at α4His-116, a known determinant of NS9283 and of agonist binding at the α4:α4 subunit interface, did not reduce CMPI potentiation. In contrast, substitutions at α4Gln-124 and α4Thr-126 reduced potentiation by CMPI and NS9283, indicating that their binding sites partially overlap. These results delineate the role of amino acid residues contributing to the α4:α4 subunit extracellular interface in nAChR potentiation. These findings also provide structural information that will facilitate the structure-based design of novel therapeutics that target selectively the (α4)3(β2)2 nAChR.
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Affiliation(s)
- Ze-Jun Wang
- From the Department of Pharmaceutical Sciences, Texas A&M Health Sciences Center, Kingsville, Texas 78363
| | - Farah Deba
- From the Department of Pharmaceutical Sciences, Texas A&M Health Sciences Center, Kingsville, Texas 78363
| | - Tasnim S Mohamed
- From the Department of Pharmaceutical Sciences, Texas A&M Health Sciences Center, Kingsville, Texas 78363
| | - David C Chiara
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Kara Ramos
- From the Department of Pharmaceutical Sciences, Texas A&M Health Sciences Center, Kingsville, Texas 78363
| | - Ayman K Hamouda
- From the Department of Pharmaceutical Sciences, Texas A&M Health Sciences Center, Kingsville, Texas 78363, .,Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Sciences Center, Bryan, Texas 77807, and
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25
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Pfisterer U, Khodosevich K. Neuronal survival in the brain: neuron type-specific mechanisms. Cell Death Dis 2017; 8:e2643. [PMID: 28252642 PMCID: PMC5386560 DOI: 10.1038/cddis.2017.64] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 01/24/2017] [Accepted: 01/31/2017] [Indexed: 12/19/2022]
Abstract
Neurogenic regions of mammalian brain produce many more neurons that will eventually survive and reach a mature stage. Developmental cell death affects both embryonically produced immature neurons and those immature neurons that are generated in regions of adult neurogenesis. Removal of substantial numbers of neurons that are not yet completely integrated into the local circuits helps to ensure that maturation and homeostatic function of neuronal networks in the brain proceed correctly. External signals from brain microenvironment together with intrinsic signaling pathways determine whether a particular neuron will die. To accommodate this signaling, immature neurons in the brain express a number of transmembrane factors as well as intracellular signaling molecules that will regulate the cell survival/death decision, and many of these factors cease being expressed upon neuronal maturation. Furthermore, pro-survival factors and intracellular responses depend on the type of neuron and region of the brain. Thus, in addition to some common neuronal pro-survival signaling, different types of neurons possess a variety of 'neuron type-specific' pro-survival constituents that might help them to adapt for survival in a certain brain region. This review focuses on how immature neurons survive during normal and impaired brain development, both in the embryonic/neonatal brain and in brain regions associated with adult neurogenesis, and emphasizes neuron type-specific mechanisms that help to survive for various types of immature neurons. Importantly, we mainly focus on in vivo data to describe neuronal survival specifically in the brain, without extrapolating data obtained in the PNS or spinal cord, and thus emphasize the influence of the complex brain environment on neuronal survival during development.
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Affiliation(s)
- Ulrich Pfisterer
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - Konstantin Khodosevich
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
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26
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Wang L, Almeida LEF, Nettleton M, Khaibullina A, Albani S, Kamimura S, Nouraie M, Quezado ZMN. Altered nocifensive behavior in animal models of autism spectrum disorder: The role of the nicotinic cholinergic system. Neuropharmacology 2016; 111:323-334. [PMID: 27638450 PMCID: PMC5075237 DOI: 10.1016/j.neuropharm.2016.09.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 08/21/2016] [Accepted: 09/12/2016] [Indexed: 02/05/2023]
Abstract
Caretakers and clinicians alike have long recognized that individuals with autism spectrum disorder (ASD) can have altered sensory processing, which can contribute to its core symptoms. However, the pathobiology of sensory alterations in ASD is poorly understood. Here we examined nocifensive behavior in ASD mouse models, the BTBR T+Itpr3tf/J (BTBR) and the fragile-X mental retardation-1 knockout (Fmr1-KO) mice. We also examined the effects of nicotine on nocifensive behavior given that nicotine, a nicotinic cholinergic receptor (nAChR) agonist that has antinociceptive effects, was shown to improve social deficits and decrease repetitive behaviors in BTBR mice. Compared to respective controls, both BTBR and Fmr1-KO had hyporesponsiveness to noxious thermal stimuli and electrical stimulation of C-sensory fibers, normal responsiveness to electrical stimulation of Aβ- and Aδ-fiber, and hyperresponsiveness to visceral pain after acetic acid intraperitoneal injection. In BTBR, nicotine at lower doses increased, whereas at higher doses, it decreased hotplate latency compared to vehicle. In a significantly different effect pattern, in control mice, nicotine had antinociceptive effects to noxious heat only at the high dose. Interestingly, these nocifensive behavior alterations and differential responses to nicotine antinociceptive effects in BTBR mice were associated with significant downregulation of α3, α4, α5, α7, β2, β3, and β4 nAChR subunits in several cerebral regions both, during embryonic development and adulthood. Taken together, these findings further implicate nAChRs in behaviors alterations in the BTBR model and lend support to the hypothesis that nAChRs may be a target for treatment of behavior deficits and sensory dysfunction in ASD.
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Affiliation(s)
- Li Wang
- The Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's Research Institute, Division of Anesthesiology, Pain and Perioperative Medicine, Children's National Health System, School of Medicine and Health Sciences, George Washington University, Washington, DC, 20010, USA
| | - Luis E F Almeida
- The Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's Research Institute, Division of Anesthesiology, Pain and Perioperative Medicine, Children's National Health System, School of Medicine and Health Sciences, George Washington University, Washington, DC, 20010, USA
| | - Margaret Nettleton
- The Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's Research Institute, Division of Anesthesiology, Pain and Perioperative Medicine, Children's National Health System, School of Medicine and Health Sciences, George Washington University, Washington, DC, 20010, USA
| | - Alfia Khaibullina
- The Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's Research Institute, Division of Anesthesiology, Pain and Perioperative Medicine, Children's National Health System, School of Medicine and Health Sciences, George Washington University, Washington, DC, 20010, USA
| | - Sarah Albani
- The Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's Research Institute, Division of Anesthesiology, Pain and Perioperative Medicine, Children's National Health System, School of Medicine and Health Sciences, George Washington University, Washington, DC, 20010, USA
| | - Sayuri Kamimura
- The Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's Research Institute, Division of Anesthesiology, Pain and Perioperative Medicine, Children's National Health System, School of Medicine and Health Sciences, George Washington University, Washington, DC, 20010, USA
| | - Mehdi Nouraie
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Zenaide M N Quezado
- The Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's Research Institute, Division of Anesthesiology, Pain and Perioperative Medicine, Children's National Health System, School of Medicine and Health Sciences, George Washington University, Washington, DC, 20010, USA; Center for Neuroscience Research, Children's Research Institute, Children's National Health System, School of Medicine and Health Sciences, George Washington University, Washington, DC, 20010, USA.
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Lombardo S, Catteau J, Besson M, Maskos U. A role for β2* nicotinic receptors in a model of local amyloid pathology induced in dentate gyrus. Neurobiol Aging 2016; 46:221-34. [DOI: 10.1016/j.neurobiolaging.2016.06.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 05/22/2016] [Accepted: 06/09/2016] [Indexed: 12/22/2022]
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Kleeman E, Nakauchi S, Su H, Dang R, Wood MA, Sumikawa K. Impaired function of α2-containing nicotinic acetylcholine receptors on oriens-lacunosum moleculare cells causes hippocampus-dependent memory impairments. Neurobiol Learn Mem 2016; 136:13-20. [PMID: 27660076 DOI: 10.1016/j.nlm.2016.09.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 09/14/2016] [Accepted: 09/18/2016] [Indexed: 01/22/2023]
Abstract
Children of mothers who smoked during pregnancy are at significantly greater risk for cognitive impairments including memory deficits, but the mechanisms underlying this effect remain to be understood. In rodent models of smoking during pregnancy, early postnatal nicotine exposure results in impaired long-term hippocampus-dependent memory, functional loss of α2-containing nicotinic acetylcholine receptors (α2∗ nAChRs) in oriens-lacunosum moleculare (OLM) cells, increased CA1 network excitation, and unexpected facilitation of long-term potentiation (LTP) at Schaffer collateral-CA1 synapses. Here we demonstrate that α2 knockout mice show the same pattern of memory impairment as previously observed in wild-type mice exposed to early postnatal nicotine. However, α2 knockout mice and α2 knockout mice exposed to early postnatal nicotine did not share all of the anomalies in hippocampal function observed in wild-type mice treated with nicotine during development. Unlike nicotine-treated wild-type mice, α2 knockout mice and nicotine-exposed α2 knockout mice did not demonstrate increased CA1 network excitation following Schaffer collateral stimulation and facilitated LTP, indicating that the effects are likely adaptive changes caused by activation of α2∗ nAChRs during nicotine exposure and are unlikely related to the associated memory impairment. Thus, the functional loss of α2∗ nAChRs in OLM cells likely plays a critical role in mediating this developmental-nicotine-induced hippocampal memory deficit.
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Affiliation(s)
- Elise Kleeman
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697-4550, USA
| | - Sakura Nakauchi
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697-4550, USA
| | - Hailing Su
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697-4550, USA
| | - Richard Dang
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697-4550, USA
| | - Marcelo A Wood
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697-4550, USA
| | - Katumi Sumikawa
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697-4550, USA.
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Grasing K. A threshold model for opposing actions of acetylcholine on reward behavior: Molecular mechanisms and implications for treatment of substance abuse disorders. Behav Brain Res 2016; 312:148-62. [PMID: 27316344 DOI: 10.1016/j.bbr.2016.06.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 06/11/2016] [Accepted: 06/13/2016] [Indexed: 12/26/2022]
Abstract
The cholinergic system plays important roles in both learning and addiction. Medications that modify cholinergic tone can have pronounced effects on behaviors reinforced by natural and drug reinforcers. Importantly, enhancing the action of acetylcholine (ACh) in the nucleus accumbens and ventral tegmental area (VTA) dopamine system can either augment or diminish these behaviors. A threshold model is presented that can explain these seemingly contradictory results. Relatively low levels of ACh rise above a lower threshold, facilitating behaviors supported by drugs or natural reinforcers. Further increases in cholinergic tone that rise above a second upper threshold oppose the same behaviors. Accordingly, cholinesterase inhibitors, or agonists for nicotinic or muscarinic receptors, each have the potential to produce biphasic effects on reward behaviors. Pretreatment with either nicotinic or muscarinic antagonists can block drug- or food- reinforced behavior by maintaining cholinergic tone below its lower threshold. Potential threshold mediators include desensitization of nicotinic receptors and biphasic effects of ACh on the firing of medium spiny neurons. Nicotinic receptors with high- and low- affinity appear to play greater roles in reward enhancement and inhibition, respectively. Cholinergic inhibition of natural and drug rewards may serve as mediators of previously described opponent processes. Future studies should evaluate cholinergic agents across a broader range of doses, and include a variety of reinforced behaviors.
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Affiliation(s)
- Kenneth Grasing
- From the Substance Abuse Research Laboratory, 151, Kansas City Veterans Affairs Medical Center, 4801 Linwood Boulevard, Kansas City, MO 64128, United States; From the Division of Clinical Pharmacology, Department of Medicine, University of Kansas School of Medicine, Kansas City, KS 66160, United States.
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Konsolaki E, Tsakanikas P, Polissidis AV, Stamatakis A, Skaliora I. Early Signs of Pathological Cognitive Aging in Mice Lacking High-Affinity Nicotinic Receptors. Front Aging Neurosci 2016; 8:91. [PMID: 27199738 PMCID: PMC4846665 DOI: 10.3389/fnagi.2016.00091] [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] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/11/2016] [Indexed: 01/29/2023] Open
Abstract
In order to address pathological cognitive decline effectively, it is critical to adopt early preventive measures in individuals considered at risk. It is therefore essential to develop approaches that identify such individuals before the onset of irreversible dementia. A deficient cholinergic system has been consistently implicated as one of the main factors associated with a heightened vulnerability to the aging process. In the present study we used mice lacking high affinity nicotinic receptors (β2-/-), which have been proposed as an animal model of accelerated/premature cognitive aging. Our aim was to identify behavioral signs that could serve as indicators or predictors of impending cognitive decline. We used test batteries in order to assess cognitive functions and additional tasks to investigate spontaneous behaviors, such as species-specific activities and exploration/locomotion in a novel environment. Our data confirm the hypothesis that β2-/- animals exhibit age-related cognitive impairments in spatial learning. In addition, they document age-related deficits in other areas, such as recognition memory, burrowing and nesting building, thereby extending the validity of this animal model for the study of pathological aging. Finally, our data reveal deficits in spontaneous behavior and habituation processes that precede the onset of cognitive decline and could therefore be useful as a non-invasive behavioral screen for identifying animals at risk. To our knowledge, this is the first study to perform an extensive behavioral assessment of an animal model of premature cognitive aging, and our results suggest that β2-nAChR dependent cognitive deterioration progressively evolves from initial subtle behavioral changes to global dementia due to the combined effect of the neuropathology and aging.
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Affiliation(s)
- Eleni Konsolaki
- Neurophysiology Laboratory, Center for Basic Research, Biomedical Research Foundation of the Academy of AthensAthens, Greece; Psychology Department, DEREE-The American College of GreeceAthens, Greece
| | - Panagiotis Tsakanikas
- Neurophysiology Laboratory, Center for Basic Research, Biomedical Research Foundation of the Academy of Athens Athens, Greece
| | - Alexia V Polissidis
- Neurophysiology Laboratory, Center for Basic Research, Biomedical Research Foundation of the Academy of Athens Athens, Greece
| | - Antonios Stamatakis
- Biology-Biochemistry Lab, School of Health Sciences, University of Athens Athens, Greece
| | - Irini Skaliora
- Neurophysiology Laboratory, Center for Basic Research, Biomedical Research Foundation of the Academy of Athens Athens, Greece
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Abstract
UNLABELLED Nicotinic acetylcholine receptors (nAChRs) play an important role in the modulation of many cognitive functions but their role in integrated network activity remains unclear. This is at least partly because of the complexity of the cholinergic circuitry and the difficulty in comparing results from in vivo studies obtained under diverse experimental conditions and types of anesthetics. Hence the role of nAChRs in the synchronization of cortical activity during slow-wave sleep is still controversial, with some studies showing they are involved in ACh-dependent EEG desynchronization, and others suggesting that this effect is mediated exclusively by muscarinic receptors. Here we use an in vitro model of endogenous network activity, in the form of recurring self-maintained depolarized states (Up states), which allows us to examine the role of high-affinity nAChRs on network dynamics in a simpler form of the cortical microcircuit. We find that mice lacking nAChRs containing the β2-subunit (β2-nAChRs) have longer and more frequent Up states, and that this difference is eliminated when β2-nAChRs in wild-type mice are blocked. We further show that endogenously released ACh can modulate Up/Down states through the activation of both β2- and α7-containing nAChRs, but through distinct mechanisms: α7-nAChRs affect only the termination of spontaneous Up states, while β2-nAChRs also regulate their generation. Finally we provide evidence that the effects of β2-subunit-containing, but not α7-subunit-containing nAChRs, are mediated through GABAB receptors. To our knowledge this is the first study documenting direct nicotinic modulation of Up/Down state activity. SIGNIFICANCE STATEMENT Through our experiments we were able to uncover a clear and previously disputed effect of nicotinic signaling in synchronized activity of neuronal networks of the cortex. We show that both high-affinity receptors (containing the β2-subunit, β2-nAChRs) and low-affinity receptors (containing the α7-subunit, α7-nAChRs) can regulate cortical network function exhibited in the form of Up/Down states. We further show that the effects of β2-nAChRs, but not α7-nAChRs, are mediated through the activation of GABAB receptors. These results suggest a possible synthesis of seemingly contradictory results in the literature and could be valuable for informing computational models of cortical function and for guiding the search for therapeutic interventions.
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Peng P, Wang Z, Jiang T, Chu S, Wang S, Xiao D. Brain-volume changes in young and middle-aged smokers: a DARTEL-based voxel-based morphometry study. CLINICAL RESPIRATORY JOURNAL 2015; 11:621-631. [PMID: 26404024 DOI: 10.1111/crj.12393] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 08/26/2015] [Accepted: 09/21/2015] [Indexed: 01/23/2023]
Affiliation(s)
- Peng Peng
- Department of Radiology; Beijing Friendship Hospital, Capital Medical University; Beijing China
| | - Zhenchang Wang
- Department of Radiology; Beijing Friendship Hospital, Capital Medical University; Beijing China
| | - Tao Jiang
- Department of Radiology; Beijing Chao-yang Hospital, Capital Medical University; Beijing China
| | - Shuilian Chu
- Clinical Research Center, Beijing Chao-yang Hospital, Capital Medical University; Beijing China
| | - Shuangkun Wang
- Department of Radiology; Beijing Chao-yang Hospital, Capital Medical University; Beijing China
| | - Dan Xiao
- Tobacco Medicine and Tobacco Cessation Center, China-Japan Friendship Hospital; Beijing China
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Featherstone RE, Siegel SJ. The Role of Nicotine in Schizophrenia. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 124:23-78. [PMID: 26472525 DOI: 10.1016/bs.irn.2015.07.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Schizophrenia is associated with by severe disruptions in thought, cognition, emotion, and behavior. Patients show a marked increase in rates of smoking and nicotine dependence relative to nonaffected individuals, a finding commonly ascribed to the potential ameliorative effects of nicotine on symptom severity and cognitive impairment. Indeed, many studies have demonstrated improvement in patients following the administration of nicotine. Such findings have led to an increased emphasis on the development of therapeutic agents to target the nicotinic system as well as increasing the impetus to understand the genetic basis for nicotinic dysfunction in schizophrenia. The goal of this review article is to provide a critical summary of evidence for the role of the nicotinic system in schizophrenia. The first part will review the role of nicotine in normalization of primary dysfunctions and endophenotypical changes found in schizophrenia. The second part will provide a summary of genetic evidence linking polymorphisms in nicotinic receptor genes to smoking and schizophrenia. The third part will summarize attempts to treat schizophrenia using agents specifically targeting nicotinic and nicotinic receptor subtypes. Although currently available antipsychotic treatments are generally able to manage some aspects of schizophrenia (e.g., positive symptoms) they fail to address several other critically effected aspects of the disease. As such, the search for novel mechanisms to treat this disease is necessary.
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Affiliation(s)
- Robert E Featherstone
- Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
| | - Steven J Siegel
- Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Nosjean A, Cressant A, de Chaumont F, Olivo-Marin JC, Chauveau F, Granon S. Acute stress in adulthood impoverishes social choices and triggers aggressiveness in preclinical models. Front Behav Neurosci 2015; 8:447. [PMID: 25610381 PMCID: PMC4285129 DOI: 10.3389/fnbeh.2014.00447] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 12/10/2014] [Indexed: 11/13/2022] Open
Abstract
Adult C57BL/6J mice are known to exhibit high level of social flexibility while mice lacking the β2 subunit of nicotinic receptors (β2(-/-) mice) present social rigidity. We asked ourselves what would be the consequences of a restraint acute stress (45 min) on social interactions in adult mice of both genotypes, hence the contribution of neuronal nicotinic receptors in this process. We therefore dissected social interaction complexity of stressed and not stressed dyads of mice in a social interaction task. We also measured plasma corticosterone levels in our experimental conditions. We showed that a single stress exposure occurring in adulthood reduced and disorganized social interaction complexity in both C57BL/6J and β2(-/-) mice. These stress-induced maladaptive social interactions involved alteration of distinct social categories and strategies in both genotypes, suggesting a dissociable impact of stress depending on the functioning of the cholinergic nicotinic system. In both genotypes, social behaviors under stress were coupled to aggressive reactions with no plasma corticosterone changes. Thus, aggressiveness appeared a general response independent of nicotinic function. We demonstrate here that a single stress exposure occurring in adulthood is sufficient to impoverish social interactions: stress impaired social flexibility in C57BL/6J mice whereas it reinforced β2(-/-) mice behavioral rigidity.
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Affiliation(s)
- Anne Nosjean
- Centre de Neuroscience Paris Sud, Université Paris Sud 11 and Centre National de la Recherche Scientifique UMR 8195 Orsay, France
| | - Arnaud Cressant
- Centre de Neuroscience Paris Sud, Université Paris Sud 11 and Centre National de la Recherche Scientifique UMR 8195 Orsay, France
| | - Fabrice de Chaumont
- Unité d'Analyse d'Images Quantitative, Institut Pasteur, Centre National de la Recherche Scientifique URA 2582 Paris, France
| | - Jean-Christophe Olivo-Marin
- Unité d'Analyse d'Images Quantitative, Institut Pasteur, Centre National de la Recherche Scientifique URA 2582 Paris, France
| | - Frédéric Chauveau
- Institut de Recherche Biomédicale des Armées, NCO, Unité NPS Brétigny-sur-Orge, France
| | - Sylvie Granon
- Centre de Neuroscience Paris Sud, Université Paris Sud 11 and Centre National de la Recherche Scientifique UMR 8195 Orsay, France
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Grupe M, Grunnet M, Bastlund JF, Jensen AA. Targeting α4β2 Nicotinic Acetylcholine Receptors in Central Nervous System Disorders: Perspectives on Positive Allosteric Modulation as a Therapeutic Approach. Basic Clin Pharmacol Toxicol 2014; 116:187-200. [DOI: 10.1111/bcpt.12361] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 11/24/2014] [Indexed: 12/11/2022]
Affiliation(s)
- Morten Grupe
- Synaptic Transmission; H. Lundbeck A/S; Valby Denmark
| | - Morten Grunnet
- Synaptic Transmission; H. Lundbeck A/S; Valby Denmark
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | | | - Anders A. Jensen
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
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36
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Lombardo S, Maskos U. Role of the nicotinic acetylcholine receptor in Alzheimer's disease pathology and treatment. Neuropharmacology 2014; 96:255-62. [PMID: 25514383 DOI: 10.1016/j.neuropharm.2014.11.018] [Citation(s) in RCA: 174] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 11/11/2014] [Accepted: 11/24/2014] [Indexed: 11/26/2022]
Abstract
Alzheimer's Disease (AD) is the major form of senile dementia, characterized by neuronal loss, extracellular deposits, and neurofibrillary tangles. It is accompanied by a loss of cholinergic tone, and acetylcholine (ACh) levels in the brain, which were hypothesized to be responsible for the cognitive decline observed in AD. Current medication is restricted to enhancing cholinergic signalling for symptomatic treatment of AD patients. The nicotinic acetylcholine receptor family (nAChR) and the muscarinic acetylcholine receptor family (mAChR) are the target of ACh in the brain. Both families of receptors are affected in AD. It was demonstrated that amyloid beta (Aβ) interacts with nAChRs. Here we discuss how Aβ activates or inhibits nAChRs, and how this interaction contributes to AD pathology. We will discuss the potential role of nAChRs as therapeutic targets. This article is part of the Special Issue entitled 'The Nicotinic Acetylcholine Receptor: From Molecular Biology to Cognition'.
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Affiliation(s)
- Sylvia Lombardo
- Département de Neuroscience, Institut Pasteur, Unité Neurobiologie Intégrative des Systèmes Cholinergiques, Paris Cedex 15, France; CNRS, UMR 3571, Paris, France.
| | - Uwe Maskos
- Département de Neuroscience, Institut Pasteur, Unité Neurobiologie Intégrative des Systèmes Cholinergiques, Paris Cedex 15, France; CNRS, UMR 3571, Paris, France
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Abstract
There have been a number of attempts to study PET radioligands for imaging nicotinic acetylcholine receptors (nAChRs) in the human brain, and the most successful tracers found are radioligands for imaging α4β2-nAChRs, which is the main cerebral nAChRs subtype. C-Nicotine and 2-[F]FA have been applied in many studies in humans. However, neither is entirely ideal and efforts have been made to develop radioligands with optimized imaging properties. Only a few reports have been published on radioligands for α7-nAChRs imaging, another important cerebral nAChRs subtype. This paper will review the development of PET radioligands for imaging cerebral nAChRs.
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Kobayashi A, Parker RL, Wright AP, Brahem H, Ku P, Oliver KM, Walz A, Lester HA, Miwa JM. Lynx1 supports neuronal health in the mouse dorsal striatum during aging: an ultrastructural investigation. J Mol Neurosci 2014; 53:525-36. [PMID: 25027556 DOI: 10.1007/s12031-014-0352-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 06/09/2014] [Indexed: 10/25/2022]
Abstract
Nicotinic acetylcholine receptors have been shown to participate in neuroprotection in the aging brain. Lynx protein modulators dampen the activity of the cholinergic system through direct interaction with nicotinic receptors. Although lynx1 null mutant mice exhibit augmented learning and plasticity, they also exhibit macroscopic vacuolation in the dorsal striatum as they age, detectable at the optical microscope level. Despite the relevance of the lynx1 gene to brain function, little is known about the cellular ultrastructure of these age-related changes. In this study, we assessed degeneration in the dorsal striatum in 1-, 3-, 7-, and 13-month-old mice, using optical and transmission electron microscopy. We observed a loss of nerve fibers, a breakdown in nerve fiber bundles, and a loss of neuronal nuclei in the 13-month-old lynx1 null striatum. At higher magnification, these nerve fibers displayed intracellular vacuoles and disordered myelin sheaths. Few or none of these morphological alterations were present in younger lynx1 null mutant mice or in heterozygous lynx1 null mutant mice at any age. These data indicate that neuronal health can be maintained by titrating lynx1 dosage and that the lynx1 gene may participate in a trade-off between neuroprotection and augmented learning.
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Affiliation(s)
- Atsuko Kobayashi
- Biology Division, California Institute of Technology, MC156-29, 1200 E. California Blvd., Pasadena, CA, 91125, USA
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Perinatal hypoxia-ischemia reduces α 7 nicotinic receptor expression and selective α 7 nicotinic receptor stimulation suppresses inflammation and promotes microglial Mox phenotype. BIOMED RESEARCH INTERNATIONAL 2014; 2014:718769. [PMID: 24757672 PMCID: PMC3976804 DOI: 10.1155/2014/718769] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 01/30/2014] [Accepted: 01/30/2014] [Indexed: 11/17/2022]
Abstract
Inflammation plays a central role in neonatal brain injury. During brain inflammation the resident macrophages of the brain, the microglia cells, are rapidly activated. In the periphery, α7 nicotinic acetylcholine receptors (α7R) present on macrophages can regulate inflammation by suppressing cytokine release. In the current study we investigated α7R expression in neonatal mice after hypoxia-ischemia (HI). We further examined possible anti-inflammatory role of α7R stimulation in vitro and microglia polarization after α7R agonist treatment. Real-time PCR analysis showed a 33% reduction in α7R expression 72 h after HI. Stimulation of primary microglial cells with LPS in combination with increasing doses of the selective α7R agonist AR-R 17779 significantly attenuated TNFα release and increased α7R transcript in microglial cells. Gene expression of M1 markers CD86 and iNOS, as well as M2 marker CD206 was not influenced by LPS and/or α7R agonist treatment. Further, Mox markers heme oxygenase (Hmox1) and sulforedoxin-1 (Srx1) were significantly increased, suggesting a polarization towards the Mox phenotype after α7R stimulation. Thus, our data suggest a role for the α7R also in the neonatal brain and support the anti-inflammatory role of α7R in microglia, suggesting that α7R stimulation could enhance the polarization towards a reparative Mox phenotype.
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40
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Konsolaki E, Skaliora I. Premature Aging Phenotype in Mice Lacking High-Affinity Nicotinic Receptors: Region-Specific Changes in Layer V Pyramidal Cell Morphology. Cereb Cortex 2014; 25:2138-48. [PMID: 24554727 DOI: 10.1093/cercor/bhu019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The mechanisms by which aging leads to alterations in brain structure and cognitive deficits are unclear. Α deficient cholinergic system has been implicated as one of the main factors that could confer a heightened vulnerability to the aging process, and mice lacking high-affinity nicotinic receptors (β2(-/-)) have been proposed as an animal model of accelerated cognitive aging. To date, however, age-related changes in neuronal microanatomy have not been studied in these mice. In the present study, we examine the neuronal structure of yellow fluorescent protein (YFP(+)) layer V neurons in 2 cytoarchitectonically distinct cortical regions in wild-type (WT) and β2(-/-) animals. We find that (1) substantial morphological differences exist between YFP(+) cells of the anterior cingulate cortex (ACC) and primary visual cortex (V1), in both genotypes; (2) in WT animals, ACC cells are more susceptible to aging compared with cells in V1; and (3) β2 deletion is associated with a regionally and temporally specific increase in vulnerability to aging. ACC cells exhibit a prematurely aged phenotype already at 4-6 months, whereas V1 cells are spared in adulthood but strongly affected in old animals. Collectively, our data reveal region-specific synergistic effects of aging and genotype and suggest distinct vulnerabilities in V1 and ACC neurons.
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Affiliation(s)
- Eleni Konsolaki
- Neurophysiology Laboratory, Division of Developmental Biology, Biomedical Research Foundation of the Academy of Athens, Athens 115 27, Greece
| | - Irini Skaliora
- Neurophysiology Laboratory, Division of Developmental Biology, Biomedical Research Foundation of the Academy of Athens, Athens 115 27, Greece
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Tang X, Zhu X, Ding B, Walton JP, Frisina RD, Su J. Age-related hearing loss: GABA, nicotinic acetylcholine and NMDA receptor expression changes in spiral ganglion neurons of the mouse. Neuroscience 2013; 259:184-93. [PMID: 24316061 DOI: 10.1016/j.neuroscience.2013.11.058] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 11/13/2013] [Accepted: 11/26/2013] [Indexed: 11/26/2022]
Abstract
Age-related hearing loss - presbycusis - is the number one communication disorder and most prevalent neurodegenerative condition of our aged population. Although speech understanding in background noise is quite difficult for those with presbycusis, there are currently no biomedical treatments to prevent, delay or reverse this condition. A better understanding of the cochlear mechanisms underlying presbycusis will help lead to future treatments. Objectives of the present study were to investigate GABAA receptor subunit α1, nicotinic acetylcholine (nACh) receptor subunit β2, and N-methyl-d-aspartate (NMDA) receptor subunit NR1 mRNA and protein expression changes in spiral ganglion neurons (SGN) of the CBA/CaJ mouse cochlea, that occur in age-related hearing loss, utilizing quantitative immunohistochemistry and semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) techniques. We found that auditory brainstem response (ABR) thresholds shifted over 40dB from 3 to 48kHz in old mice compared to young adults. DPOAE thresholds also shifted over 40dB from 6 to 49kHz in old mice, and their amplitudes were significantly decreased or absent in the same frequency range. SGN density decreased with age in basal, middle and apical turns, and SGN density of the basal turn declined the most. A positive correlation was observed between SGN density and ABR wave 1amplitude. mRNA and protein expression of GABAAR α1 and AChR β2 decreased with age in SGNs in the old mouse cochlea. mRNA and protein expression of NMDAR NR1 increased with age in SGNs of the old mice. These findings demonstrate that there are functionally-relevant age-related changes of GABAAR, nAChR, NMDAR expression in CBA mouse SGNs reflecting their degeneration, which may be related to functional changes in cochlear synaptic transmission with age, suggesting biological mechanisms for peripheral age-related hearing loss.
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Affiliation(s)
- X Tang
- Department of Otolaryngology Head and Neck Surgery, First Affiliated Hospital, Guangxi Medical University, 6 Shuangyong Road, Nanning, Guangxi, 530021, China; Department Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, United States; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33620, United States.
| | - X Zhu
- Department Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, United States; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33620, United States.
| | - B Ding
- Department Communication Sciences & Disorders, University of South Florida, Tampa, FL 33620, United States; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33620, United States.
| | - J P Walton
- Department Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, United States; Department Communication Sciences & Disorders, University of South Florida, Tampa, FL 33620, United States; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33620, United States.
| | - R D Frisina
- Department Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, United States; Department Communication Sciences & Disorders, University of South Florida, Tampa, FL 33620, United States; Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33620, United States.
| | - J Su
- Department of Otolaryngology Head and Neck Surgery, First Affiliated Hospital, Guangxi Medical University, 6 Shuangyong Road, Nanning, Guangxi, 530021, China.
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Okada H, Ouchi Y, Ogawa M, Futatsubashi M, Saito Y, Yoshikawa E, Terada T, Oboshi Y, Tsukada H, Ueki T, Watanabe M, Yamashita T, Magata Y. Alterations in α4β2 nicotinic receptors in cognitive decline in Alzheimer’s aetiopathology. Brain 2013; 136:3004-17. [DOI: 10.1093/brain/awt195] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Inestrosa NC, Godoy JA, Vargas JY, Arrazola MS, Rios JA, Carvajal FJ, Serrano FG, Farias GG. Nicotine prevents synaptic impairment induced by amyloid-β oligomers through α7-nicotinic acetylcholine receptor activation. Neuromolecular Med 2013; 15:549-69. [PMID: 23842742 DOI: 10.1007/s12017-013-8242-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 06/26/2013] [Indexed: 11/30/2022]
Abstract
An emerging view on Alzheimer disease's (AD) pathogenesis considers amyloid-β (Aβ) oligomers as a key factor in synaptic impairment and rodent spatial memory decline. Alterations in the α7-nicotinic acetylcholine receptor (α7-nAChR) have been implicated in AD pathology. Herein, we report that nicotine, an unselective α7-nAChR agonist, protects from morphological and synaptic impairments induced by Aβ oligomers. Interestingly, nicotine prevents both early postsynaptic impairment and late presynaptic damage induced by Aβ oligomers through the α7-nAChR/phosphatidylinositol-3-kinase (PI3K) signaling pathway. On the other hand, a cross-talk between α7-nAChR and the Wnt/β-catenin signaling pathway was revealed by the following facts: (1) nicotine stabilizes β-catenin, in a concentration-dependent manner; (2) nicotine prevents Aβ-induced loss of β-catenin through the α7-nAChR; and (3) activation of canonical Wnt/β-catenin signaling induces α7-nAChR expression. Analysis of the α7-nAChR promoter indicates that this receptor is a new Wnt target gene. Taken together, these results demonstrate that nicotine prevents memory deficits and synaptic impairment induced by Aβ oligomers. In addition, nicotine improves memory in young APP/PS1 transgenic mice before extensive amyloid deposition and senile plaque development, and also in old mice where senile plaques have already formed. Activation of the α7-nAChR/PI3K signaling pathway and its cross-talk with the Wnt signaling pathway might well be therapeutic targets for potential AD treatments.
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Affiliation(s)
- Nibaldo C Inestrosa
- Centro de Envejecimiento y Regeneración (CARE), Pontificia Universidad Católica de Chile, PO Box 114-D, Santiago, Chile.
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Drenan RM, Lester HA. Insights into the neurobiology of the nicotinic cholinergic system and nicotine addiction from mice expressing nicotinic receptors harboring gain-of-function mutations. Pharmacol Rev 2012; 64:869-79. [PMID: 22885704 DOI: 10.1124/pr.111.004671] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are ligand-gated, cation-selective ion channels expressed throughout the brain. Although these channels have been investigated for several decades, it is still challenging 1) to identify the important nAChR subunits in cholinergic transmission and nicotine dependence and 2) to develop nAChR subtype-specific ligands. To overcome these challenges, we and others have studied mice expressing mutant, gain-of-function nAChR subunits. In this review, we discuss this research approach and the results it has yielded to date. Gain-of-function mutations, including those in nAChR subunits, provide an approach that is complementary to loss-of-function studies such as gene knockouts; the former allows one to answer questions of sufficiency and the latter addresses questions of necessity. Mutant mice expressing gain-of-function nAChR subunits are commonly produced using traditional gene targeting in embryonic stem cells, but novel approaches such as bacterial artificial chromosome transgenesis have yielded important insights as well. α7 nAChRs were the first nAChRs to be targeted with a gain-of-function mutation, followed by a pair of α4 nAChR gain-of-function mutant mice. These α4 nAChR gain-of-function mice (α4 L9'S mice, followed by α4 L9'A mice) provided an important system to probe α4 nAChR function in vivo, particularly in the dopamine reward system. α6 nAChR gain-of-function mice provided the first robust system allowing specific manipulation of this receptor subtype. Other targeted mutations in various nAChR subunits have also been produced and have yielded important insights into nicotinic cholinergic biology. As nAChR research advances and more details associated with nAChR expression and function emerge, we expect that existing and new mouse lines expressing gain-of-function nAChR subunits will continue to provide new insights.
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Affiliation(s)
- Ryan M Drenan
- Purdue University, Department of Medicinal Chemistry and Molecular Pharmacology, West Lafayette, IN 47907, USA.
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Plasticity of prefrontal attention circuitry: upregulated muscarinic excitability in response to decreased nicotinic signaling following deletion of α5 or β2 subunits. J Neurosci 2012; 31:16458-63. [PMID: 22072695 DOI: 10.1523/jneurosci.3600-11.2011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Attention depends on cholinergic stimulation of nicotinic and muscarinic acetylcholine receptors in the medial prefrontal cortex. Pyramidal neurons in layer VI of this region express cholinergic receptors of both families and play an important role in attention through their feedback projections to the thalamus. Here, we investigate how nicotinic and muscarinic cholinergic receptors affect the excitability of these neurons using whole-cell recordings in acute brain slices of prefrontal cortex. Since attention deficits have been documented in both rodents and humans having genetic abnormalities in nicotinic receptors, we focus in particular on how the cholinergic excitation of layer VI neurons is altered by genetic deletion of either of two key nicotinic receptor subunits, the accessory α5 subunit or the ligand-binding β2 subunit. We find that the cholinergic excitation of layer VI neurons is dominated by nicotinic receptors in wild-type mice and that the reduction or loss of this nicotinic stimulation is accompanied by a surprising degree of plasticity in excitatory muscarinic receptors. These findings suggest that disrupting nicotinic receptors fundamentally alters the mechanisms and timing of excitation in prefrontal attentional circuitry.
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Muscarinic and nicotinic acetylcholine receptor agonists and allosteric modulators for the treatment of schizophrenia. Neuropsychopharmacology 2012; 37:16-42. [PMID: 21956443 PMCID: PMC3238081 DOI: 10.1038/npp.2011.199] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Muscarinic and nicotinic acetylcholine (ACh) receptors (mAChRs and nAChRs) are emerging as important targets for the development of novel treatments for the symptoms associated with schizophrenia. Preclinical and early proof-of-concept clinical studies have provided strong evidence that activators of specific mAChR (M(1) and M(4)) and nAChR (α(7) and α(2)β(4)) subtypes are effective in animal models of antipsychotic-like activity and/or cognitive enhancement, and in the treatment of positive and cognitive symptoms in patients with schizophrenia. While early attempts to develop selective mAChR and nAChR agonists provided important preliminary findings, these compounds have ultimately failed in clinical development due to a lack of true subtype selectivity and subsequent dose-limiting adverse effects. In recent years, there have been major advances in the discovery of highly selective activators for the different mAChR and nAChR subtypes with suitable properties for optimization as potential candidates for clinical trials. One novel strategy has been to identify ligands that activate a specific receptor subtype through actions at sites that are distinct from the highly conserved ACh-binding site, termed allosteric sites. These allosteric activators, both allosteric agonists and positive allosteric modulators, of mAChR and nAChR subtypes demonstrate unique mechanisms of action and high selectivity in vivo, and may provide innovative treatment strategies for schizophrenia.
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Huang PS, Son JH, Abbott L, Winzer-Serhan U. Regulated expression of neuronal SIRT1 and related genes by aging and neuronal β2-containing nicotinic cholinergic receptors. Neuroscience 2011; 196:189-202. [DOI: 10.1016/j.neuroscience.2011.09.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Revised: 09/02/2011] [Accepted: 09/02/2011] [Indexed: 02/07/2023]
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Yalcin I, Charlet A, Cordero-Erausquin M, Tessier LH, Picciotto MR, Schlichter R, Poisbeau P, Freund-Mercier MJ, Barrot M. Nociceptive thresholds are controlled through spinal β2-subunit-containing nicotinic acetylcholine receptors. Pain 2011; 152:2131-2137. [DOI: 10.1016/j.pain.2011.05.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 04/08/2011] [Accepted: 05/08/2011] [Indexed: 11/29/2022]
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Bourgeois JP, Meas-Yeadid V, Lesourd AM, Faure P, Pons S, Maskos U, Changeux JP, Olivo-Marin JC, Granon S. Modulation of the Mouse Prefrontal Cortex Activation by Neuronal Nicotinic Receptors during Novelty Exploration but not by Exploration of a Familiar Environment. Cereb Cortex 2011; 22:1007-15. [DOI: 10.1093/cercor/bhr159] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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50
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Serreau P, Chabout J, Suarez SV, Naudé J, Granon S. Beta2-containing neuronal nicotinic receptors as major actors in the flexible choice between conflicting motivations. Behav Brain Res 2011; 225:151-9. [PMID: 21784105 DOI: 10.1016/j.bbr.2011.07.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 07/06/2011] [Accepted: 07/10/2011] [Indexed: 10/17/2022]
Abstract
Beside a critical role in nicotine addiction, the role of nicotinic receptors in cognitive or emotional processes remains difficult to elucidate, mostly because of a lack of specificity of compounds and because they up or down regulate easily. Using knockout mice may be one key to elucidate the role of nicotinic receptors stimulated by their endogenous ligand acetylcholine. We and others have previously explored the behaviour of mice knockout for the beta2-subunit containing nicotinic receptor - β2*nAChRs - β2(-/-) mice. These mice exhibit a particular kind of hyperactive locomotion, with profound deficits in cognitive and social interaction tasks, only when they have to show flexible choices. We wonder here whether the latter is due to a lack of motor control - i.e. motor impulsivity, a lack of estimation of reward value - i.e. cognitive impulsivity, and/or a lack of appropriate ranking or choice between different motivations. We designed behavioural tasks allowing the study of these distinct processes in mice. Our current results highlight the important role of β2*nAChRs in flexible behaviours in conflicting situations, such as social contact, spatial exploration and food consumption. They also show that the cognitive deficits exhibited by β2(-/-) mice cannot be explained by impaired inhibitory behaviours. Although social cognition is considerably enriched in humans as compared to rodents, we provide here novel data for the neurobiology of flexible social behaviours that could ultimately be useful for humans. Indeed, the ability to show flexible behaviours and to display adapted social interactions is profoundly impaired in a myriad of psychiatric disorders.
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Affiliation(s)
- P Serreau
- Neurobiologie Intégrative des Systèmes Cholinergiques, Département Neurosciences, Institut Pasteur and CNRS URA 2182, 25 Rue du Docteur Roux, 75015 Paris, France
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