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Khodabandeh Z, Valilo M, Velaei K, Pirpour Tazehkand A. The potential role of nicotine in breast cancer initiation, development, angiogenesis, invasion, metastasis, and resistance to therapy. Breast Cancer 2022; 29:778-789. [PMID: 35583594 DOI: 10.1007/s12282-022-01369-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/27/2022] [Indexed: 01/03/2023]
Abstract
A large body of research studying the relationship between tobacco and cancer has led to the knowledge that smoking cigarettes adversely affects cancer treatment while contributing to the development of various tobacco-related cancers. Nicotine is the main addictive component of tobacco smoke and promotes angiogenesis, proliferation, and epithelial-mesenchymal transition (EMT) while promoting growth and metastasis of tumors. Nicotine generally acts through the induction of the nicotinic acetylcholine receptors (nAChRs), although the contribution of other receptor subunits has also been reported. Nicotine contributes to the pathogenesis of a wide range of cancers including breast cancer through its carcinogens such as (4-methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N-nitrosonornicotine (NNN). Current study aims to review the mechanistic function of nicotine in the initiation, development, angiogenesis, invasion, metastasis, and apoptosis of breast cancer with the main focus on nicotine acetylcholine receptors (nAChRs) and nAChR-mediated signaling pathways as well as on its potential for the development of an effective treatment against breast cancer. Moreover, we will try to demonstrate how nicotine leads to poor treatment response in breast cancer by enhancing the population, proliferation, and self-renewal of cancer stem cells (CSCs) through the activation of α7-nAChR receptors.
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Affiliation(s)
- Zhila Khodabandeh
- Department of Biology, Faculty of Science, Urmia University, Urmia, Iran
| | - Mohammad Valilo
- Department of Clinical Biochemistry and Medical Laboratories, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Kobra Velaei
- Department of Anatomical Sciences, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Abbas Pirpour Tazehkand
- Department of Clinical Biochemistry and Medical Laboratories, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
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2
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Duan F, Zeng C, Liu S, Gong J, Hu J, Li H, Tan H. α1-nAchR-Mediated Signaling Through Lipid Raft Is Required for Nicotine-Induced NLRP3 Inflammasome Activation and Nicotine-Accelerated Atherosclerosis. Front Cell Dev Biol 2021; 9:724699. [PMID: 34490270 PMCID: PMC8416509 DOI: 10.3389/fcell.2021.724699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 07/16/2021] [Indexed: 01/13/2023] Open
Abstract
Background Nicotine exerts direct effects on multiple cell types in the cardiovascular system by associating with its high-affinity nicotinic acetylcholine receptors (nAchRs). Lipid raft is a membrane microdomain that recruits various receptors and signaling molecules for coordinating cellular immune response and many others signaling processes. Here, we aim to identify the essential role of lipid raft in mediating nicotine-triggered inflammatory and nicotine-accelerated atherosclerosis, and to figure out the specific receptor of nicotine-induced Nod-like receptor protein 3 (NLRP3) inflammasome activation in macrophage. Methods and Results ApoE–/– mice were fed with a high-fat diet to build atherosclerosis model. Methyl-β-cyclodextrin was used to interrupt intact lipid raft. We confirmed that nicotine triggered NLRP3 inflammasome activation and induced macrophage migration into atherosclerotic plaque, thus accelerated atherosclerosis in apoE–/– mice fed with a high-fat diet. Mechanically, nicotine increased the expression of α1-nAChR and stimulated the accumulation of α1-nAChR in lipid raft, leading to NLRP3 inflammasome activation in macrophage. Conversely, silencing of α1-nAChR in macrophage sufficiently blocked the pro-inflammasome activation effect of nicotine, indicating that α1-nAChR was the specific receptor for nicotine in triggering NLRP3 inflammasome in macrophage. Furthermore, both the destruction of lipid raft by methyl-β-cyclodextrin and the interference of lipid raft clustering by silencing acid sphingomyelinase reversed nicotine-induced NLRP3 inflammasome activation by reducing the accumulation of α1-nAChR in lipid raft in macrophage, suggesting lipid raft–mediated accumulation of α1-nAChR was the key event in regulating the pro-inflammatory effects of nicotine in macrophage. Importantly, nicotine-induced NLRP3 inflammasome activation and macrophage migration into atherosclerotic plaque were reversed by methyl-β-cyclodextrin, making a significant improvement for atherosclerosis in apoE–/– mice fed with a high-fat diet. Conclusion α1-nAChR-mediated signaling through lipid raft is required for NLRP3 inflammasome activation and pro-atherosclerotic property of nicotine.
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Affiliation(s)
- Fengqi Duan
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Cheng Zeng
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Sijun Liu
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Jianfeng Gong
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Jia Hu
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Hongyu Li
- Laboratory Animal Center, Sun Yat-sen University, Guangzhou, China
| | - Hongmei Tan
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Laboratory Animal Center, Sun Yat-sen University, Guangzhou, China.,The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
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Sarlak S, Lalou C, Amoedo ND, Rossignol R. Metabolic reprogramming by tobacco-specific nitrosamines (TSNAs) in cancer. Semin Cell Dev Biol 2020; 98:154-166. [PMID: 31699542 DOI: 10.1016/j.semcdb.2019.09.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 08/25/2019] [Accepted: 09/02/2019] [Indexed: 12/21/2022]
Abstract
Metabolic reprogramming is a hallmark of cancer and the link between oncogenes activation, tumor supressors inactivation and bioenergetics modulation is well established. However, numerous carcinogenic environmental factors are responsible for early cancer initiation and their impact on metabolic reprogramming just starts to be deciphered. For instance, it was recently shown that UVB irradiation triggers metabolic reprogramming at the pre-cancer stage with implication for skin cancer detection and therapy. These observations foster the need to study the early changes in tissue metabolism following exposure to other carcinogenic events. According to the International Agency for Research on Cancer (IARC), tobacco smoke is a major class I-carcinogenic environmental factor that contains different carcinogens, but little is known on the impact of tobacco smoke on tissue metabolism and its participation to cancer initiation. In particular, tobacco-specific nitrosamines (TSNAs) play a central role in tobacco-smoke mediated cancer initiation. Here we describe the recent advances that have led to a new hypothesis regarding the link between nitrosamines signaling and metabolic reprogramming in cancer.
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Affiliation(s)
- Saharnaz Sarlak
- INSERM U1211, 33000 Bordeaux, France; Bordeaux University, 146 rue Léo Saignat, 33000 Bordeaux, France
| | - Claude Lalou
- INSERM U1211, 33000 Bordeaux, France; Bordeaux University, 146 rue Léo Saignat, 33000 Bordeaux, France
| | - Nivea Dias Amoedo
- CELLOMET, Functional Genomics Center (CGFB), 146 rue Léo Saignat, 33000 Bordeaux, France
| | - Rodrigue Rossignol
- INSERM U1211, 33000 Bordeaux, France; Bordeaux University, 146 rue Léo Saignat, 33000 Bordeaux, France; CELLOMET, Functional Genomics Center (CGFB), 146 rue Léo Saignat, 33000 Bordeaux, France.
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4
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Abstract
The neurotransmitter acetylcholine (ACh) acts as an autocrine growth factor for human lung cancer. Several lines of evidence show that lung cancer cells express all of the proteins required for the uptake of choline (choline transporter 1, choline transporter-like proteins) synthesis of ACh (choline acetyltransferase, carnitine acetyltransferase), transport of ACh (vesicular acetylcholine transport, OCTs, OCTNs) and degradation of ACh (acetylcholinesterase, butyrylcholinesterase). The released ACh binds back to nicotinic (nAChRs) and muscarinic receptors on lung cancer cells to accelerate their proliferation, migration and invasion. Out of all components of the cholinergic pathway, the nAChR-signaling has been studied the most intensely. The reason for this trend is due to genome-wide data studies showing that nicotinic receptor subtypes are involved in lung cancer risk, the relationship between cigarette smoke and lung cancer risk as well as the rising popularity of electronic cigarettes considered by many as a "safe" alternative to smoking. There are a small number of articles which review the contribution of the other cholinergic proteins in the pathophysiology of lung cancer. The primary objective of this review article is to discuss the function of the acetylcholine-signaling proteins in the progression of lung cancer. The investigation of the role of cholinergic network in lung cancer will pave the way to novel molecular targets and drugs in this lethal malignancy.
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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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Lewis JA, Yakel JL, Pandya AA. Levamisole: A Positive Allosteric Modulator for the α3β4 Nicotinic Acetylcholine Receptors Prevents Weight Gain in the CD-1 Mice on a High Fat Diet. Curr Pharm Des 2018; 23:1869-1872. [PMID: 27908269 DOI: 10.2174/1381612822666161201145648] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/01/2016] [Indexed: 11/22/2022]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) regulate the function of multiple neurotransmitter pathways throughout the central nervous system. This includes nAChRs found on the proopiomelanocortin neurons in the hypothalamus. Activation of these nAChRs by nicotine causes a decrease in the consumption of food in rodents. This study tested the effect of subtype selective allosteric modulators for nAChRs on the body weight of CD-1 mice. Levamisole, an allosteric modulator for the α3β4 subtype of nAChRs, prevented weight gain in mice that were fed a high fat diet. PNU-120596 and desformylflustrabromine were observed to be selective PAMs for the α7 and α4β2 nAChR, respectively. Both of these compounds failed to prevent weight gain in the CD-1 mice. These results suggest that the modulation of hypothalamic α3β4 nAChRs is an important factor in regulating food intake, and the PAMs for these receptors need further investigation as potential therapeutic agents for controlling weight gain.
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Affiliation(s)
- Jeanne A Lewis
- Department of Bioscience, College of Rural and Community Development, Room 116, Harper Building, 4280, Geist Road, University of Alaska Fairbanks, Fairbanks, AK. 99709-3419. United States
| | - Jerrel L Yakel
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709. United States
| | - Anshul A Pandya
- Room 116, Harper Building, 4280, Geist Road, University of Alaska Fairbanks, Fairbanks, AK. 99709- 3419. United States
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7
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Jie X, Li X, Song JQ, Wang D, Wang JH. Anti-inflammatory and autonomic effects of electroacupuncture in a rat model of diet-induced obesity. Acupunct Med 2018; 36:103-109. [PMID: 29487062 DOI: 10.1136/acupmed-2016-011223] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2017] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To study the effect of electroacupuncture (EA) on the cholinergic anti-inflammatory pathway (CAP) by measurement of vagal activity in rats with high-fat diet (HFD)-induced obesity. METHODS Diet-induced obesity (DIO) was induced in 30 rats by feeding them a HFD for 12 weeks. A further 10 rats fed normal food comprised the lean diet (LD) control group. DIO rats were further subdivided into three groups that received a HFD only (HFD group, n=10), a HFD plus electroacupuncture (HFD+EA group, n=10) or a HFD plus minimal acupuncture (HFD+MA group, n=10). EA and MA treatments were continued for 8 weeks. Heart rate variability (HRV) was used to measure the function of the autonomic nervous system before and after treatment. ELISA was used to determine acetylcholine (ACh) and tumour necrosis factor (TNF)-α levels in the serum. Real-time PCR was used to assess the mRNA expression of α7-subtype nicotinic acetylcholine cholinergic receptors (α7nAChRs) and TNF-α in the mesenteric white adipose tissues (MWAT). RESULTS EA but not MA significantly reduced rats' bodyweight. No difference was found in the low frequency (LF), high frequency (HF) and the balance between LF and HF (LF/HF) components of HRV before treatment. After the EA intervention, HF was elevated and LF/HF was reduced in the HFD+EA group comparedwith the HFD group. TNF-α in the serum and MWAT were increased in the HFD group, but were reduced in the HFD+EA group. Furthermore, EA promoted expression of α7nAChRs and ACh in the MWAT. There was no difference between the HFD and HFD+MA groups for any indices. CONCLUSIONS EA enhanced vagal activity, promoted ACh release and activated α7nAChRs in the MWAT, leading to inhibition of proinflammatory cytokine production.
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Affiliation(s)
- Xiaoyan Jie
- Department of Neurosurgical Intensive Care Unit, Nanyang Second General Hospital, Nanyang, Henan, China
| | - Xu Li
- Department of Medicine, Nanyang Second General Hospital, Nanyang, Henan, China
| | - Jian-Qing Song
- Department of Neurosurgical Intensive Care Unit, Nanyang Second General Hospital, Nanyang, Henan, China
| | - Dan Wang
- Department of Neurosurgical Intensive Care Unit, Nanyang Second General Hospital, Nanyang, Henan, China
| | - Jian-Hua Wang
- Department of Neurosurgical Intensive Care Unit, Nanyang Second General Hospital, Nanyang, Henan, China
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Govind AP, Vallejo YF, Stolz JR, Yan JZ, Swanson GT, Green WN. Selective and regulated trapping of nicotinic receptor weak base ligands and relevance to smoking cessation. eLife 2017; 6. [PMID: 28718768 PMCID: PMC5546804 DOI: 10.7554/elife.25651] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 07/03/2017] [Indexed: 01/11/2023] Open
Abstract
To better understand smoking cessation, we examined the actions of varenicline (Chantix) during long-term nicotine exposure. Varenicline reduced nicotine upregulation of α4β2-type nicotinic receptors (α4β2Rs) in live cells and neurons, but not for membrane preparations. Effects on upregulation depended on intracellular pH homeostasis and were not observed if acidic pH in intracellular compartments was neutralized. Varenicline was trapped as a weak base in acidic compartments and slowly released, blocking 125I-epibatidine binding and desensitizing α4β2Rs. Epibatidine itself was trapped; 125I-epibatidine slow release from acidic vesicles was directly measured and required the presence of α4β2Rs. Nicotine exposure increased epibatidine trapping by increasing the numbers of acidic vesicles containing α4β2Rs. We conclude that varenicline as a smoking cessation agent differs from nicotine through trapping in α4β2R-containing acidic vesicles that is selective and nicotine-regulated. Our results provide a new paradigm for how smoking cessation occurs and suggest how more effective smoking cessation reagents can be designed. DOI:http://dx.doi.org/10.7554/eLife.25651.001 Tobacco continues to be widely used worldwide, primarily via cigarette smoking, and is a leading cause of preventable deaths. Stopping smoking is difficult because the nicotine in tobacco is highly addictive, and so several drugs have been developed to help people break their addiction. Varenicline (also known by the trade name Chantix) is a commonly prescribed anti-smoking drug, but it is not fully understood how it works. Nicotine affects the brain by binding to proteins called nicotinic acetylcholine receptors (nAChRs) that sit on the surface of neurons. This binding releases a number of chemical signals, including some that produce feelings of pleasure. Over time, the receptors become less sensitive to nicotine and produce more “high-affinity” binding sites for nicotine to bind to. This adaptation is one reason why stopping smoking can produce strong feelings of withdrawal. Previously, varenicline was thought to partially activate nAChRs, preventing nicotine from binding to the receptors. However, this can only explain how varenicline counteracts the rapid-acting effects of nicotine, not nicotine’s longer-term effects. Furthermore, it was not known how nAChR signaling responds to long-term exposure to a combination of both drugs (as occurs when people try to quit smoking with the aid of varenicline). Now, Govind et al. reveal how varenicline reverses the effect of long-term nicotine exposure on nAChR signaling. Both varenicline and nicotine accumulate in acidic compartments – called vesicles – inside cells, where they become charged and less able to move through the cell membrane. When the vesicles also contain high-affinity nAChRs, varenicline becomes trapped inside them and is only slowly released. By contrast, nicotine is not trapped because it exits the vesicles more rapidly. Long-term exposure to nicotine greatly increased the number of vesicles that contained high-affinity nAChRs, thereby trapping more varenicline. One consequence of trapping varenicline was that the activity of the nAChRs on the surface of the neuron was diminished, apparently through the slow release of the trapped varenicline from the acidic vesicles. This slow release causes the receptors to enter a “desensitized” state in which they do not signal. Understanding how varenicline counteracts the long-term effects of nicotine on nAChR signaling will help us to design more effective anti-smoking drugs. Govind et al. also found that compounds similar to varenicline become trapped in vesicles, but it is not clear how the degree of trapping of a compound correlates with how effectively it combats nicotine addiction. The results may also help us to understand and treat addictions to other drugs of abuse, such as opioids, amphetamines and cocaine, which have chemical properties that mean they might also be selectively trapped in acidic vesicles. DOI:http://dx.doi.org/10.7554/eLife.25651.002
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Affiliation(s)
- Anitha P Govind
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Yolanda F Vallejo
- National Institute of Dental and Craniofacial Research at the National Institutes of Health, , United States
| | - Jacob R Stolz
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Evanston, United States
| | - Jing-Zhi Yan
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Evanston, United States
| | - Geoffrey T Swanson
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Evanston, United States
| | - William N Green
- Department of Neurobiology, University of Chicago, Chicago, United States.,Marine Biological Laboratory, Woods Hole, United States
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Lee JS, Kim HJ, Ahn CH, Jeon CJ. Expression of Nicotinic Acetylcholine Receptor α4 and β2 Subunits on Direction-Selective Retinal Ganglion Cells in the Rabbit. Acta Histochem Cytochem 2017; 50:29-37. [PMID: 28386148 PMCID: PMC5374101 DOI: 10.1267/ahc.16024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 12/26/2016] [Indexed: 11/22/2022] Open
Abstract
The direction selectivity of the retina is a distinct mechanism that is critical function of eyes for survival. The direction-selective retinal ganglion cells (DS RGCs) strongly respond to a preferred direction, but rarely respond to opposite direction or null directional visual stimuli. The DS RGCs are sensitive to acetylcholine, which is secreted from starburst amacrine cells (SACs) to the DS RGCs. Here, we investigated the existence and distribution of the nicotinic acetylcholine receptor (nAChR) α4 and β2 subunits on the dendritic arbors of the DS RGCs in adult rabbit retina using immunocytochemistry. The DS RGCs were injected with Lucifer yellow to identify their dendritic morphology. The double-labeled images of dendrites and nAChR subunits were visualized for reconstruction using high-resolution confocal microscopy. Although our results revealed that the distributional pattern of the nAChR subunits on the dendritic arbors of the DS RGCs was not asymmetric in the adult rabbit retina, the distribution of nAChR α4 and β2 subunits and molecular profiles of cholinergic inputs to DS RGCs in adult rabbit retina provide anatomical evidence for direction selectivity.
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Affiliation(s)
- Jun-Seok Lee
- Department of Biology, School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, College of Natural Sciences, and Brain Science and Engineering Institute, Kyungpook National University
| | - Hyun-Jin Kim
- Department of Life Sciences, Pohang University of Science and Technology
| | - Chang-Hyun Ahn
- Department of Biology, School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, College of Natural Sciences, and Brain Science and Engineering Institute, Kyungpook National University
| | - Chang-Jin Jeon
- Department of Biology, School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, College of Natural Sciences, and Brain Science and Engineering Institute, Kyungpook National University
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10
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Wu J, Liu Q, Tang P, Mikkelsen JD, Shen J, Whiteaker P, Yakel JL. Heteromeric α7β2 Nicotinic Acetylcholine Receptors in the Brain. Trends Pharmacol Sci 2016; 37:562-574. [PMID: 27179601 DOI: 10.1016/j.tips.2016.03.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 03/27/2016] [Accepted: 03/30/2016] [Indexed: 10/21/2022]
Abstract
The α7 nicotinic acetylcholine receptor (α7 nAChR) is highly expressed in the brain, where it maintains various neuronal functions including (but not limited to) learning and memory. In addition, the protein expression levels of α7 nAChRs are altered in various brain disorders. The classic rule governing α7 nAChR assembly in the mammalian brain was that it was assembled from five α7 subunits to form a homomeric receptor pentamer. However, emerging evidence demonstrates the presence of heteromeric α7 nAChRs in heterologously expressed systems and naturally in brain neurons, where α7 subunits are co-assembled with β2 subunits to form a novel type of α7β2 nAChR. Interestingly, the α7β2 nAChR exhibits distinctive function and pharmacology from traditional homomeric α7 nAChRs. We review recent advances in probing the distribution, function, pharmacology, pathophysiology, and stoichiometry of the heteromeric α7β2 nAChR, which have provided new insights into the understanding of a novel target of cholinergic signaling.
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Affiliation(s)
- Jie Wu
- Department of Physiology, Shantou University Medicine College, Shantou, Guangdong, China; Divisions of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013-4496, USA.
| | - Qiang Liu
- Divisions of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013-4496, USA
| | - Pei Tang
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Jens D Mikkelsen
- Neurobiology Research Unit, University Hospital Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Jianxin Shen
- Department of Physiology, Shantou University Medicine College, Shantou, Guangdong, China
| | - Paul Whiteaker
- Divisions of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013-4496, USA
| | - Jerrel L Yakel
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH)/DHHS, Research Triangle Park, North Carolina 27709, USA
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11
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Synthesis and biological activities of indolizine derivatives as alpha-7 nAChR agonists. Eur J Med Chem 2016; 115:94-108. [PMID: 26994846 DOI: 10.1016/j.ejmech.2016.03.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 12/16/2022]
Abstract
Human α7 nicotinic acetylcholine receptor (nAChR) is a promising therapeutic target for the treatment of schizophrenia accompanied with cognitive impairment. Herein, we report the synthesis and agonistic activities of a series of indolizine derivatives targeting to α7 nAChR. The results show that all synthesized compounds have affinity to α7 nAChR and some give strong agonistic activity, particularly most active agonists show higher potency than control EVP-6124. The docking and structure-activity relationship studies provide insights to develop more potent novel α7 nAChR agonists.
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12
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Melroy-Greif WE, Stitzel JA, Ehringer MA. Nicotinic acetylcholine receptors: upregulation, age-related effects and associations with drug use. GENES, BRAIN, AND BEHAVIOR 2016; 15:89-107. [PMID: 26351737 PMCID: PMC4780670 DOI: 10.1111/gbb.12251] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 09/01/2015] [Accepted: 09/02/2015] [Indexed: 12/16/2022]
Abstract
Nicotinic acetylcholine receptors are ligand-gated ion channels that exogenously bind nicotine. Nicotine produces rewarding effects by interacting with these receptors in the brain's reward system. Unlike other receptors, chronic stimulation by an agonist induces an upregulation of receptor number that is not due to increased gene expression in adults; while upregulation also occurs during development and adolescence there have been some opposing findings regarding a change in corresponding gene expression. These receptors have also been well studied with regard to human genetic associations and, based on evidence suggesting shared genetic liabilities between substance use disorders, numerous studies have pointed to a role for this system in comorbid drug use. This review will focus on upregulation of these receptors in adulthood, adolescence and development, as well as the findings from human genetic association studies which point to different roles for these receptors in risk for initiation and continuation of drug use.
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Affiliation(s)
- Whitney E. Melroy-Greif
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, CA, USA
| | - Jerry A. Stitzel
- Institute for Behavioral Genetics, University of Colorado Boulder, CO, USA
- Department of Integrative Physiology, University of Colorado Boulder, CO, USA
| | - Marissa A. Ehringer
- Institute for Behavioral Genetics, University of Colorado Boulder, CO, USA
- Department of Integrative Physiology, University of Colorado Boulder, CO, USA
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13
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Cooke JP. New Insights Into Tobacco-Induced Vascular Disease: Clinical Ramifications. Methodist Debakey Cardiovasc J 2015; 11:156-9. [PMID: 26634022 DOI: 10.14797/mdcj-11-3-156] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Tobacco smoke contains more than 4,000 compounds. These include phenols, carbonyls, and nitrosamines that may be irritants and carcinogens; particulate matter such as tars; volatiles and gases such as carbon monoxide; and nicotine. Many of these compounds may contribute to the adverse health effects of tobacco. For example, recent findings have shown that the angiogenic and proliferative effects of nicotine are mediated by activation of nicotinic receptors on the vascular cells. Nicotine-induced activation of vascular cells may contribute to pathological neovascularization in cancer, age-related macular degeneration, and atherosclerosis. This review focuses on how nicotine adversely affects cardiovascular health and highlights intriguing new data about nicotine's potent angiogenic and proliferative properties.
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Affiliation(s)
- John P Cooke
- Houston Methodist Research Institute, Houston Methodist Hospital, Houston, Texas
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Liu Q, Kuo YP, Shen J, Lukas RJ, Wu J. Roles of nicotinic acetylcholine receptor β subunit cytoplasmic loops in acute desensitization and single-channel features. Neuroscience 2015; 289:315-23. [PMID: 25536046 DOI: 10.1016/j.neuroscience.2014.12.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 12/12/2014] [Accepted: 12/13/2014] [Indexed: 01/11/2023]
Abstract
To evaluate physiological roles of the large, second cytoplasmic loops (C2) situated between the M3 and M4 transmembrane domains of nicotinic acetylcholine receptor (nAChR) subunits. We have constructed chimeric β2 (β2χ) and β4 (β4χ) subunits in which the "nested" C2 domains (but not the "proximal" sequences of ∼14 residues immediately adjacent to the M3 or M4 domains) of these β subunits were replaced by the corresponding sequence from the serotonin 5-HT3A receptor subunit. We previously reported that heterologously expressed nAChR containing α4 and β2χ subunits displayed a faster whole-cell current decay in its agonist response compared to responses of all-wild-type α4β2-nAChR. This suggests an unexpected, functional role for the C2 domain of the β2 subunit in α4β2-nAChR acute desensitization. Here we report that there also is faster desensitization of α4β4χ-nAChR relative to α4β4-nAChR stably and heterologously expressed in the human SH-EP1 cell-line. In addition, cell-attached, single-channel recording shows that both acetylcholine-activated α4β2χ- and α4β4χ-nAChR have a significantly lower mean open probability, shorter mean open-time, and a longer mean closed-time than their fully wild-type counterparts while not having different conductance amplitudes. These findings reveal microscopic bases for the faster desensitization of α4(∗)-nAChR containing chimeric instead of wild-type β subunits. Our findings also remain consistent with novel and unexpected roles of β subunit-nested C2 domains in modulation of α4(∗)-nAChR function.
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Affiliation(s)
- Q Liu
- Division of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013-4496, United States.
| | - Y-P Kuo
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013-4496, United States
| | - J Shen
- Department of Physiology, Shantou University of Medical College, Shantou, Guangdong, China
| | - R J Lukas
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013-4496, United States
| | - J Wu
- Division of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013-4496, United States; Department of Physiology, Shantou University of Medical College, Shantou, Guangdong, China.
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Shen J, Wu J. Nicotinic Cholinergic Mechanisms in Alzheimer's Disease. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 124:275-92. [PMID: 26472533 DOI: 10.1016/bs.irn.2015.08.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative condition characterized by increased accumulation of Aβ and degeneration of cholinergic signaling between basal forebrain and hippocampus. Nicotinic acetylcholine receptors (nAChRs) are important mediators of cholinergic signaling in modulation of learning and memory function. Accumulating lines of evidence indicate that a nAChR subtype, α7 receptor (α7-nAChR), plays an important role in modulations of excitatory neurotransmitter release, improvement of learning and memory ability, and enhancement of cognitive function. Importantly, the expression and function of α7-nAChRs is altered in the brain of AD animal models and AD patients, suggesting that this nAChR subtype participates in AD pathogenesis and may serve as a novel therapeutic target for AD treatment. However, the mechanisms underlying the role of α7-nAChRs in AD pathogenesis are very complex, and either neuroprotective effects or neurotoxic effects may occur through the α7-nAChRs. These effects depend on the levels of α7-nAChR expression and function, disease stages, or the use of α7-nAChR agonists, antagonists, or allosteric modulators. In this chapter, we summarize recent progresses in the roles of α7-nAChRs played in AD pathogenesis and therapy.
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Affiliation(s)
- Jianxin Shen
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong, China
| | - Jie Wu
- Department of Physiology, Shantou University Medical College, Shantou, Guangdong, China; Divisions of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix Arizona, USA.
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Luo J, Lindstrom J. Antigen-specific immunotherapeutic vaccine for experimental autoimmune myasthenia gravis. THE JOURNAL OF IMMUNOLOGY 2014; 193:5044-55. [PMID: 25288571 DOI: 10.4049/jimmunol.1401392] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Myasthenia gravis (MG) and experimental autoimmune myasthenia gravis (EAMG) are caused by Ab-mediated autoimmune responses to muscle nicotinic acetylcholine receptors (AChRs) that impair neuromuscular transmission, thereby causing muscle weakness. Previously, we discovered that i.p. injection of a therapeutic vaccine consisting of bacterially expressed cytoplasmic domains of human AChR subunits reduced the development of chronic EAMG in rats. In this article, we show that immunization with the therapeutic vaccine in adjuvants does not induce EAMG and, thus, is safe. The potency and efficacy of the therapeutic vaccine were greatly increased by s.c. administration of repeated low doses in IFA. Onset of chronic EAMG could be prevented. Established chronic EAMG could be rapidly reversed, modeling therapy of chronic MG. Therapy reduced pathological Abs assayed by immune precipitation of a main immunogenic region chimera. Successfully treated rats exhibited long-term resistance to reinduction of EAMG, suggesting a lasting cure of MG. A long-term effect of therapy was to change the isotype of the pathogenic Ab response from IgG2b, which fixes complement, to IgG1, which does not. Prevention and reversal of chronic EAMG was not caused by the isotype switch, but the isotype switch may contribute to resistance to reinduction of EAMG. Immunization with AChR cytoplasmic domains in adjuvant is promising as a safe, Ag-specific, potent, effective, rapidly acting, and long-lasting therapeutic approach to MG.
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Affiliation(s)
- Jie Luo
- Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, PA 19104
| | - Jon Lindstrom
- Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, PA 19104
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Xue J, Yang S, Seng S. Mechanisms of Cancer Induction by Tobacco-Specific NNK and NNN. Cancers (Basel) 2014; 6:1138-56. [PMID: 24830349 PMCID: PMC4074821 DOI: 10.3390/cancers6021138] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 04/13/2014] [Accepted: 04/28/2014] [Indexed: 11/17/2022] Open
Abstract
Tobacco use is a major public health problem worldwide. Tobacco-related cancers cause millions of deaths annually. Although several tobacco agents play a role in the development of tumors, the potent effects of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN) are unique. Metabolically activated NNK and NNN induce deleterious mutations in oncogenes and tumor suppression genes by forming DNA adducts, which could be considered as tumor initiation. Meanwhile, the binding of NNK and NNN to the nicotinic acetylcholine receptor promotes tumor growth by enhancing and deregulating cell proliferation, survival, migration, and invasion, thereby creating a microenvironment for tumor growth. These two unique aspects of NNK and NNN synergistically induce cancers in tobacco-exposed individuals. This review will discuss various types of tobacco products and tobacco-related cancers, as well as the molecular mechanisms by which nitrosamines, such as NNK and NNN, induce cancer.
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Affiliation(s)
- Jiaping Xue
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA.
| | - Suping Yang
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
| | - Seyha Seng
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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18
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Somm E, Guérardel A, Maouche K, Toulotte A, Veyrat-Durebex C, Rohner-Jeanrenaud F, Maskos U, Hüppi PS, Schwitzgebel VM. Concomitant alpha7 and beta2 nicotinic AChR subunit deficiency leads to impaired energy homeostasis and increased physical activity in mice. Mol Genet Metab 2014; 112:64-72. [PMID: 24685552 DOI: 10.1016/j.ymgme.2014.03.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Revised: 03/12/2014] [Accepted: 03/12/2014] [Indexed: 12/18/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated cation channels well characterized in neuronal signal transmission. Moreover, recent studies have revealed nAChR expression in nonneuronal cell types throughout the body, including tissues involved in metabolism. In the present study, we screen gene expression of nAChR subunits in pancreatic islets and adipose tissues. Mice pancreatic islets present predominant expression of α7 and β2 nAChR subunits but at a lower level than in central structures. Characterization of glucose and energy homeostasis in α7β2nAChR(-/-) mice revealed no major defect in insulin secretion and sensitivity but decreased glycemia apparently unrelated to gluconeogenesis or glycogenolysis. α7β2nAChR(-/-) mice presented an increase in lean and bone body mass and a decrease in fat storage with normal body weight. These observations were associated with elevated spontaneous physical activity in α7β2nAChR(-/-) mice, mainly due to elevation in fine vertical (rearing) activity while their horizontal (ambulatory) activity remained unchanged. In contrast to α7nAChR(-/-) mice presenting glucose intolerance and insulin resistance associated to excessive inflammation of adipose tissue, the present metabolic phenotyping of α7β2nAChR(-/-) mice revealed a metabolic improvement possibly linked to the increase in spontaneous physical activity related to central β2nAChR deficiency.
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Affiliation(s)
- Emmanuel Somm
- Division of Development and Growth, Department of Paediatrics, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
| | - Audrey Guérardel
- Division of Development and Growth, Department of Paediatrics, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Kamel Maouche
- Université Paris-Diderot, Sorbonne-Paris-Cité, Laboratoire B2PE (Biologie et Pathologie du Pancréas Endocrine), Unité BFA (Biologie Fonctionnelle et Adaptative), CNRS UMR 8251, Paris, France
| | - Audrey Toulotte
- Division of Development and Growth, Department of Paediatrics, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Christelle Veyrat-Durebex
- Laboratory of Metabolism, Department of Internal Medicine Specialties, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Françoise Rohner-Jeanrenaud
- Laboratory of Metabolism, Department of Internal Medicine Specialties, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Uwe Maskos
- Département de Neuroscience, Institut Pasteur, Unité Neurobiologie intégrative des systèmes cholinergiques, Paris, France
| | - Petra S Hüppi
- Division of Development and Growth, Department of Paediatrics, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Valérie M Schwitzgebel
- Division of Development and Growth, Department of Paediatrics, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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Nencini A, Castaldo C, Comery TA, Dunlop J, Genesio E, Ghiron C, Haydar S, Maccari L, Micco I, Turlizzi E, Zanaletti R, Zhang J. Design and synthesis of a hybrid series of potent and selective agonists of α7 nicotinic acetylcholine receptor. Eur J Med Chem 2014; 78:401-18. [PMID: 24704613 DOI: 10.1016/j.ejmech.2014.03.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 02/10/2014] [Accepted: 03/11/2014] [Indexed: 11/29/2022]
Abstract
α7 nicotinic acetylcholine receptor agonists are promising therapeutic candidates for the treatment of cognitive impairment. As a follow up of our internal medicinal chemistry program we investigated a novel series of α7 nAChR agonists. Starting from molecular docking studies on two series of molecules recently developed in our laboratories, an alternative scaffold was designed attempting to combine the optimal features of these previously identified urea and pyrazole compounds. Based on our previous SAR knowledge and on predicted drug-like properties, a small library was synthesized in parallel manner, affording compounds with excellent α7 nAChR activity, selectivity and preliminary ADME profile.
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Affiliation(s)
- Arianna Nencini
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy.
| | - Cristiana Castaldo
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Thomas A Comery
- Neuroscience Research Unit, Pfizer, Eastern Point Road, Groton, CT 06340, United States
| | - John Dunlop
- Neuroscience Research Unit, Pfizer, Eastern Point Road, Groton, CT 06340, United States
| | - Eva Genesio
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Chiara Ghiron
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Simon Haydar
- Neuroscience Research Unit, Pfizer, Eastern Point Road, Groton, CT 06340, United States
| | - Laura Maccari
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Iolanda Micco
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Elisa Turlizzi
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Riccardo Zanaletti
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Jean Zhang
- Neuroscience Research Unit, Pfizer, Eastern Point Road, Groton, CT 06340, United States
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20
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Kim HJ, Jeon CJ. Synaptic pattern of nicotinic acetylcholine receptor α7 and β2 subunits on the direction-selective retinal ganglion cells in the postnatal mouse retina. Exp Eye Res 2014; 122:54-64. [PMID: 24631336 DOI: 10.1016/j.exer.2014.02.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 02/18/2014] [Accepted: 02/25/2014] [Indexed: 11/26/2022]
Abstract
Direction-selective retinal ganglion cells (DS RGCs) respond strongly to a stimulus that moves in their preferred direction, but respond weakly or do not respond to a stimulus that moves in the opposite or null direction. DS RGCs are sensitive to acetylcholine, and starburst amacrine cells (SACs) make cholinergic synapses on DS RGCs. We studied the distributions of nicotinic acetylcholine receptor (nAChR) α7 and β2 subunits on the dendritic arbors of DS RGCs to search for anisotropies that contribute to the directional preferences of DS RGCs. The DS RGCs from the retinas of postnatal mice (postnatal day P5, P10, and P15) were injected with Lucifer yellow, and injected cells were identified by their dendritic morphology. The dendrites of the DS RGCs were labeled with antibodies for either the nAChR α7 or β2 subunit as well as postsynaptic density protein-95 (PSD-95), visualized by confocal microscopy, and reconstructed from high-resolution confocal images. The distribution of nAChR subunits on the dendritic arbors in both the ON and OFF layers of the RGCs revealed an asymmetrical pattern on early postnatal day P5. However, the distributions of nAChR subunits on the dendritic arbors were not asymmetric on P10 and P15. Our results therefore provide anatomical and developmental evidence suggesting that the nAChR α7 and β2 subunits may involve in the early direction-selectivity formation of DS RGCs in the mouse retina.
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Affiliation(s)
- Hyun Jin Kim
- Department of Biology, School of Life Sciences, KNU Creative BioResearch Group (BK21 Plus Program), College of Natural Sciences, and Brain Science and Engineering Institute, Kyungpook National University, Daegu 702-701, South Korea; Department of Life Sciences, Pohang University of Science and Technology, Pohang, Kyungpook 790-784, South Korea
| | - Chang Jin Jeon
- Department of Biology, School of Life Sciences, KNU Creative BioResearch Group (BK21 Plus Program), College of Natural Sciences, and Brain Science and Engineering Institute, Kyungpook National University, Daegu 702-701, South Korea.
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21
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Nicotinic Cholinergic Signaling in Adipose Tissue and Pancreatic Islets Biology: Revisited Function and Therapeutic Perspectives. Arch Immunol Ther Exp (Warsz) 2013; 62:87-101. [DOI: 10.1007/s00005-013-0266-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 11/14/2013] [Indexed: 12/14/2022]
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Pandya AA, Yakel JL. Effects of neuronal nicotinic acetylcholine receptor allosteric modulators in animal behavior studies. Biochem Pharmacol 2013; 86:1054-62. [PMID: 23732296 PMCID: PMC3797251 DOI: 10.1016/j.bcp.2013.05.018] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 05/20/2013] [Accepted: 05/21/2013] [Indexed: 12/11/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are ligand-gated cation-conducting transmembrane channels from the cys-loop receptor superfamily. The neuronal subtypes of these receptors (e.g. the α7 and α4β2 subtypes) are involved in neurobehavioral processes such as anxiety, the central processing of pain, food intake, nicotine seeking behavior, and a number of cognitive functions like learning and memory. Neuronal nAChR dysfunction is involved in the pathophysiology of many neurological disorders, and behavioral studies in animals are useful models to assess the effects of compounds that act on these receptors. Allosteric modulators are ligands that bind to the receptors at sites other than the orthosteric site where acetylcholine, the endogenous agonist for the nAChRs, binds. While conventional ligands for the neuronal nAChRs have been studied for their behavioral effects in animals, allosteric modulators for these receptors have only recently gained attention, and research on their behavioral effects is growing rapidly. Here we will discuss the behavioral effects of allosteric modulators of the neuronal nAChRs.
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Affiliation(s)
- Anshul A Pandya
- Chukchi Campus, Department of Bio-science, College of Rural and Community Development, University of Alaska Fairbanks, P.O. Box 297, Kotzebue, AK 99752-0297, USA.
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23
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Pandya AA, Yakel JL. Activation of the α7 nicotinic ACh receptor induces anxiogenic effects in rats which is blocked by a 5-HT₁a receptor antagonist. Neuropharmacology 2013; 70:35-42. [PMID: 23321689 PMCID: PMC3640667 DOI: 10.1016/j.neuropharm.2013.01.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 12/19/2012] [Accepted: 01/06/2013] [Indexed: 12/13/2022]
Abstract
The α7 nicotinic acetylcholine receptor (nAChR) is highly expressed in different regions of the brain and is associated with cognitive function as well as anxiety. Agonists and positive allosteric modulators (PAMs) of the α7 subtype of nAChRs have been shown to improve cognition. Previously nicotine, which activates both α7 and non-α7 subtypes of nAChRs, has been shown to have an anxiogenic effect in behavioral tests. In this study, we compared the effects of the α7-selective agonist (PNU-282987) and PAM (PNU-120596) in a variety of behavioral tests in Sprague Dawley rats to look at their effects on learning and memory as well as anxiety. We found that neither PNU-282987 nor PNU-120596 improved spatial-learning or episodic memory by themselves. However when cognitive impairment was induced in the rats with scopolamine (1 mg/kg), both PNU-120596 and PNU-282987 were able to reverse this memory impairment and restore it back to normal levels. While PNU-120596 reversed the scopolamine-induced cognitive impairment, it did not have any adverse effect on anxiety. PNU-282987 on the other hand displayed an increase in anxiety-like behavior at a higher dose (10 mg/kg) that was significantly reduced by the serotonin 5-HT₁a receptor antagonist WAY-100135. However the α7 receptor antagonist methyllycaconitine was unable to reverse these anxiety-like effects seen with PNU-282987. These results suggest that α7 nAChR PAMs are pharmacologically advantageous over agonists, and should be considered for further development as therapeutic drugs targeting the α7 receptors.
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Affiliation(s)
- Anshul A Pandya
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, MD F2-08, PO Box 12233, NC 27709, USA.
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Dunlop J, Peri R, Terstappen GC, Bowlby M. Functional screening of α7 nicotinic receptor ligands. Expert Opin Drug Discov 2013; 3:623-8. [PMID: 23506144 DOI: 10.1517/17460441.3.6.623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND The α7 nicotinic acetylcholine receptor, a ligand-gated ion channel, is an attractive drug discovery target in schizophrenia and Alzheimer's disease. OBJECTIVE We have evaluated the various approaches to discovering ligands targeting the α7 nicotinic receptor to define the current paradigm driving drug discovery efforts in this area. METHODS Assays using functional read-outs as a consequence of α7 nicotinic receptor activation have been reviewed. CONCLUSION Functional assays using fluorescence-based optical methods in combination with direct electrophysiological recordings of channel function currently provide an integrated approach to the discovery of α7 nicotinic receptor targeted ligands.
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Affiliation(s)
- John Dunlop
- Neuroscience Discovery Research, Wyeth Research, CN-8000, Princeton, NJ 08543, USA +1 732 274 4193 ; +1 732 274 4755 ;
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25
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Liu Q, Emadi S, Shen JX, Sierks MR, Wu J. Human α4β2 nicotinic acetylcholine receptor as a novel target of oligomeric α-synuclein. PLoS One 2013; 8:e55886. [PMID: 23437071 PMCID: PMC3577813 DOI: 10.1371/journal.pone.0055886] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 01/07/2013] [Indexed: 12/22/2022] Open
Abstract
Cigarette smoking is associated with a decreased incidence of Parkinson disease (PD) through unknown mechanisms. Interestingly, a decrease in the numbers of α4β2 nicotinic acetylcholine receptors (α4β2-nAChRs) in PD patients suggests an α4β2-nAChR-mediated cholinergic deficit in PD. Although oligomeric forms of α-synuclein have been recognized to be toxic and involved in the pathogenesis of PD, their direct effects on nAChR-mediated cholinergic signaling remains undefined. Here, we report for the first time that oligomeric α-synuclein selectively inhibits human α4β2-nAChR-mediated currents in a dose-dependent, non-competitive and use-independent manner. We show that pre-loading cells with guanyl-5'-yl thiophosphate fails to prevent this inhibition, suggesting that the α-synuclein-induced inhibition of α4β2-nAChR function is not mediated by nAChR internalization. By using a pharmacological approach and cultures expressing transfected human nAChRs, we have shown a clear effect of oligomeric α-synuclein on α4β2-nAChRs, but not on α4β4- or α7-nAChRs, suggesting nAChR subunit selectivity of oligomeric α-synuclein-induced inhibition. In addition, by combining the size exclusion chromatography and atomic force microscopy (AFM) analyses, we find that only large (>4 nm) oligomeric α-synuclein aggregates (but not monomeric, small oligomeric or fibrillar α-synuclein aggregates) exhibit the inhibitory effect on human α4β2-nAChRs. Collectively, we have provided direct evidence that α4β2-nAChR is a sensitive target to mediate oligomeric α-synuclein-induced modulation of cholinergic signaling, and our data imply that therapeutic strategies targeted toward α4β2-nAChRs may have potential for developing new treatments for PD.
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Affiliation(s)
- Qiang Liu
- Divisions of Neurology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona, United States of America
| | - Sharareh Emadi
- Department of Chemical Engineering, Arizona State University, Tempe, Arizona, United States of America
| | - Jian-Xin Shen
- Department of Physiology, Shantou University of Medical College, Shantou, People’s Republic of China
| | - Michael R. Sierks
- Department of Chemical Engineering, Arizona State University, Tempe, Arizona, United States of America
| | - Jie Wu
- Divisions of Neurology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona, United States of America
- Department of Physiology, Shantou University of Medical College, Shantou, People’s Republic of China
- Department of Basic Medical Sciences, University of Arizona College of Medicine Phoenix, Arizona, United States of America
- * E-mail:
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26
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Arnold LE, Anand R, Aman M. Varenicline in autistic disorder: hypothesis and case report of single-patient crossover. J Child Adolesc Psychopharmacol 2013; 23:61-4. [PMID: 23350866 DOI: 10.1089/cap.2012.0025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | - Rene Anand
- Department of Pharmacology, Ohio State University, Columbus, Ohio
| | - Michael Aman
- Department of Psychiatry, Ohio State University, Columbus, Ohio
- Department of Psychology, Ohio State University, Columbus, Ohio
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27
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Yamamoto Y, Fukunaga K. Donepezil rescues the medial septum cholinergic neurons via nicotinic ACh receptor stimulation in olfactory bulbectomized mice. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/aad.2013.24021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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28
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Zanaletti R, Bettinetti L, Castaldo C, Cocconcelli G, Comery T, Dunlop J, Gaviraghi G, Ghiron C, Haydar SN, Jow F, Maccari L, Micco I, Nencini A, Scali C, Turlizzi E, Valacchi M. Discovery of a novel alpha-7 nicotinic acetylcholine receptor agonist series and characterization of the potent, selective, and orally efficacious agonist 5-(4-acetyl[1,4]diazepan-1-yl)pentanoic acid [5-(4-methoxyphenyl)-1H-pyrazol-3-yl] amide (SEN15924, WAY-361789). J Med Chem 2012; 55:4806-23. [PMID: 22468936 DOI: 10.1021/jm300247y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Alpha-7 nicotinic acetylcholine receptors (α7 nAChR) are implicated in the modulation of many cognitive functions such as attention, working memory, and episodic memory. For this reason, α7 nAChR agonists represent promising therapeutic candidates for the treatment of cognitive impairment associated with Alzheimer's disease (AD) and schizophrenia. A medicinal chemistry effort, around our previously reported chemical series, permitted the discovery of a novel class of α7 nAChR agonists with improved selectivity, in particular against the α3 receptor subtype and better ADME profile. The exploration of this series led to the identification of 5-(4-acetyl[1,4]diazepan-1-yl)pentanoic acid [5-(4-methoxyphenyl)-1H-pyrazol-3-yl] amide (25, SEN15924, WAY-361789), a novel, full agonist of the α7 nAChR that was evaluated in vitro and in vivo. Compound 25 proved to be potent and selective, and it demonstrated a fair pharmacokinetic profile accompanied by efficacy in rodent behavioral cognition models (novel object recognition and auditory sensory gating).
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Affiliation(s)
- Riccardo Zanaletti
- Siena Biotech SpA , Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy.
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Turcanu D, Kirtok N, Eibl C, Guendisch D, LaGamma E, Nankova B. Nicotinic receptor partial agonists alter catecholamine homeostasis and response to nicotine in PC12 cells. Neurosci Lett 2012; 516:212-6. [DOI: 10.1016/j.neulet.2012.03.088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 02/16/2012] [Accepted: 03/29/2012] [Indexed: 12/22/2022]
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Sitzia F, Brown JT, Randall AD, Dunlop J. Voltage- and Temperature-Dependent Allosteric Modulation of α7 Nicotinic Receptors by PNU120596. Front Pharmacol 2011; 2:81. [PMID: 22207849 PMCID: PMC3246268 DOI: 10.3389/fphar.2011.00081] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Accepted: 11/30/2011] [Indexed: 11/13/2022] Open
Abstract
Alpha7 nicotinic acetylcholine receptors (α7 nAChR) are widely distributed throughout the central nervous system and are found at particularly high levels in the hippocampus and cortex. Several lines of evidence indicate that pharmacological enhancement of α7 nAChRs function could be a potential therapeutic route to alleviate disease-related cognitive deficits. A recent pharmacological approach adopted to increase α7 nAChR activity has been to identify selective positive allosteric modulators (PAMs). α7 nAChR PAMs have been divided into two classes: type I PAMs increase agonist potency with only subtle effects on kinetics, whereas type II agents produce additional dramatic effects on desensitization and deactivation kinetics. Here we report novel observations concerning the pharmacology of the canonical type II PAM, PNU120596. Using patch clamp analysis of acetylcholine (ACh)-mediated currents through recombinant rat α7 nAChR we show that positive allosteric modulation measured in two different ways is greatly attenuated when the temperature is raised to near physiological levels. Furthermore, PNU120596 largely removes the strong inward rectification usually exhibited by α7 nAChR-mediated responses.
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Affiliation(s)
- Fabrio Sitzia
- Pfizer Applied Neurophysiology Group, School of Physiology and Pharmacology, University of Bristol Bristol, UK
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31
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Pandya A, Yakel JL. Allosteric modulators of the α4β2 subtype of neuronal nicotinic acetylcholine receptors. Biochem Pharmacol 2011; 82:952-8. [PMID: 21596025 PMCID: PMC3162104 DOI: 10.1016/j.bcp.2011.04.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 04/28/2011] [Accepted: 04/29/2011] [Indexed: 02/07/2023]
Abstract
Nicotinic acetylcholine receptors are ligand-gated ion conducting transmembrane channels from the Cys-loop receptor super-family. The α4β2 subtype is the predominant heteromeric subtype of nicotinic receptors found in the brain. Allosteric modulators for α4β2 receptors interact at a site other than the orthosteric site where acetylcholine binds. Many compounds which act as allosteric modulators of the α4β2 receptors have been identified, with both positive and negative effects. Such allosteric modulators either increase or decrease the response induced by agonist on the α4β2 receptors. Here we discuss the concept of allosterism as it pertains to the α4β2 receptors and summarize the important features of allosteric modulators for this nicotinic receptor subtype.
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Affiliation(s)
- Anshul Pandya
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA.
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32
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Terry AV, Decker MW. Neurobiology of nAChRs and cognition: a mini review of Dr. Jerry J. Buccafusco's contributions over a 25 year career. Biochem Pharmacol 2011; 82:883-90. [PMID: 21684265 PMCID: PMC3162099 DOI: 10.1016/j.bcp.2011.06.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 06/02/2011] [Accepted: 06/02/2011] [Indexed: 12/16/2022]
Abstract
This review highlights some of the many contributions of the late Dr. Jerry J. Buccafusco to the neurobiology of nicotinic acetylcholine receptors (nAChRs) and cognition over a 25 year period. The article is written by two of Dr. Buccafusco's professional colleagues, one from academia and one from the pharmaceutical industry. While Dr. Buccafusco's expertise in the cholinergic field was extensive, his insights into the practical relevance of his work (with a long-term goal of formulating new drug development strategies) were unique, and a great asset to both the basic science community and pharmaceutical companies. In 1988, Dr. Buccafusco's laboratory was the first to report the cognitive enhancing action of low doses of nicotine in non-human primates. Since that time he studied a large number of novel pro-cognitive agents from several pharmacological classes in rodents as well as monkeys. Based on years of observing paradoxical effects of nicotinic ligands in vitro and in vivo, Dr. Buccafusco made the provocative argument that it might be possible to develop new chemical entities (with pro-cognitive actions) that have the ability to desensitize nAChRs without producing an antecedent agonist action. Some of his more recent work focused on development of single molecular entities that act on multiple CNS targets (including nAChRs) to enhance cognition, provide neuroprotection, and/or provide additional therapeutic actions (e.g., antipsychotic effects). Dr. Buccafusco's influence will live on in the work of the numerous graduate students, postdoctoral fellows, and junior faculty that he mentored over the years who now serve in prestigious positions throughout the world.
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Affiliation(s)
- Alvin V Terry
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, GA 30912, United States.
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Pandya A, Yakel JL. Allosteric modulator Desformylflustrabromine relieves the inhibition of α2β2 and α4β2 nicotinic acetylcholine receptors by β-amyloid(1-42) peptide. J Mol Neurosci 2011; 45:42-7. [PMID: 21424792 PMCID: PMC3235685 DOI: 10.1007/s12031-011-9509-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 03/01/2011] [Indexed: 10/18/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are pentameric transmembrane proteins that belong to the cys-loop ligand-gated ion channel family. These receptors are widely expressed in the brain and implicated in the pathophysiology of many neurological conditions, including Alzheimer's disease (AD), where typical symptoms include the loss of cognitive function and dementia. The presence of extracellular neuritic plaques composed of β amyloid (Aβ(1-42)) peptide is a characteristic feature of AD. Desformylflustrabromine (dFBr) is a positive allosteric modulator (PAM) for α4β2 nAChRs since it increases peak ACh responses without inducing a response on its own. Previously, the effect of dFBr on the α2β2 nAChR subtype was not known. The action of dFBr was tested on α2β2 receptors expressed in Xenopus oocytes. It was found that dFBr is also a PAM for the α2β2 receptor. Next we tested whether dFBr had any effect on the previously known block of both the α4β2 and α2β2 receptors by Aβ(1-42). We found that the functional blockade of ACh-induced currents in oocytes expressing α4β2 and α2β2 receptors by Aβ(1-42) was prevented by dFBr. We conclude that dFBr is a positive allosteric modulator for both α4β2 and α2β2 subtypes of nAChRs and that it also relieves the blockade of these receptors by Aβ(1-42). This study demonstrates that PAMs for the non-α7 nAChRs have the potential to develop into clinically applicable drugs for AD and other disorders.
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Affiliation(s)
- Anshul Pandya
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
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González-Mariscal L, Quirós M, Díaz-Coránguez M. ZO proteins and redox-dependent processes. Antioxid Redox Signal 2011; 15:1235-53. [PMID: 21294657 DOI: 10.1089/ars.2011.3913] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
SIGNIFICANCE ZO-1, ZO-2, and ZO-3 are scaffold proteins of the tight junction (TJ) that belong to the MAGUK protein family characterized for exhibiting PDZ, SH3, and GuK domains. ZO proteins are present only in multicellular organisms, being the placozoa the first to have them. ZO proteins associate among themselves and with other integral and adaptor proteins of the TJ, of the ZA and of gap junctions, as with numerous signaling proteins and the actin cytoskeleton. ZO proteins are also present at the nucleus of proliferating cells. RECENT ADVANCES Oxidative stress disassembles the TJs of endothelial and epithelial cells. CRITICAL ISSUES Oxidative stress alters ZO proteins expression and localization, in conditions like hypoxia, bacterial and viral infections, vitamin deficiencies, age-related diseases, diabetes and inflammation, alcohol and tobacco consumption. FUTURE DIRECTIONS Molecules present in the signaling pathways triggered by oxidative stress can be targets for therapeutic intervention.
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Affiliation(s)
- Lorenza González-Mariscal
- Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies (Cinvestav), Mexico DF, México.
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35
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Lakhan SE, Kirchgessner A. Anti-inflammatory effects of nicotine in obesity and ulcerative colitis. J Transl Med 2011; 9:129. [PMID: 21810260 PMCID: PMC3163205 DOI: 10.1186/1479-5876-9-129] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 08/02/2011] [Indexed: 01/03/2023] Open
Abstract
Cigarette smoke is a major risk factor for a number of diseases including lung cancer and respiratory infections. Paradoxically, it also contains nicotine, an anti-inflammatory alkaloid. There is increasing evidence that smokers have a lower incidence of some inflammatory diseases, including ulcerative colitis, and the protective effect involves the activation of a cholinergic anti-inflammatory pathway that requires the α7 nicotinic acetylcholine receptor (α7nAChR) on immune cells. Obesity is characterized by chronic low-grade inflammation, which contributes to insulin resistance. Nicotine significantly improves glucose homeostasis and insulin sensitivity in genetically obese and diet-induced obese mice, which is associated with suppressed adipose tissue inflammation. Inflammation that results in disruption of the epithelial barrier is a hallmark of inflammatory bowel disease, and nicotine is protective in ulcerative colitis. This article summarizes current evidence for the anti-inflammatory effects of nicotine in obesity and ulcerative colitis. Selective agonists for the α7nAChR could represent a promising pharmacological strategy for the treatment of inflammation in obesity and ulcerative colitis. Nevertheless, we should keep in mind that the anti-inflammatory effects of nicotine could be mediated via the expression of several nAChRs on a particular target cell.
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Affiliation(s)
- Shaheen E Lakhan
- Global Neuroscience Initiative Foundation, Los Angeles, CA, USA.
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36
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Wu J, Lukas RJ. Naturally-expressed nicotinic acetylcholine receptor subtypes. Biochem Pharmacol 2011; 82:800-7. [PMID: 21787755 DOI: 10.1016/j.bcp.2011.07.067] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 07/01/2011] [Accepted: 07/05/2011] [Indexed: 12/31/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) warrant attention, as they play many critical roles in brain and body function and have been implicated in a number of neurological and psychiatric disorders, including nicotine dependence. nAChRs are composed as diverse subtypes containing specific combinations of genetically-distinct subunits and that have different functional properties, distributions, and pharmacological profiles. There had been confidence that the rules that define ranges of assembly partners for specific subunits were well-established, especially for the more prominent nAChR subtypes. However, we review here some newer findings indicating that nAChRs having largely the same, major subunits exist as isoforms with unexpectedly different properties. Moreover, we also summarize our own studies indicating that novel nAChR subtypes exist and/or have distributions not heretofore described. Importantly, the nAChRs that exist as new isoforms or subtypes or have interesting distributions require alteration in thinking about their roles in health and disease.
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Affiliation(s)
- Jie Wu
- Division of Neurology, Barrow Neurological Institute, 350 West Thomas Road, Phoenix, AZ 85013, United States.
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37
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The identification of a novel mutation of nicotinic acetylcholine receptor gene CHRNB2 in a Chinese patient: Its possible implication in non-familial nocturnal frontal lobe epilepsy. Epilepsy Res 2011; 95:94-9. [DOI: 10.1016/j.eplepsyres.2011.03.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 02/27/2011] [Accepted: 03/06/2011] [Indexed: 11/21/2022]
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38
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Nicotinic acetylcholine receptor signaling in tumor growth and metastasis. JOURNAL OF ONCOLOGY 2011; 2011:456743. [PMID: 21541211 PMCID: PMC3085312 DOI: 10.1155/2011/456743] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Accepted: 01/28/2011] [Indexed: 12/19/2022]
Abstract
Cigarette smoking is highly correlated with the onset of a variety of human cancers, and continued smoking is known to abrogate the beneficial effects of cancer therapy. While tobacco smoke contains hundreds of molecules that are known carcinogens, nicotine, the main addictive component of tobacco smoke, is not carcinogenic. At the same time, nicotine has been shown to promote cell proliferation, angiogenesis, and epithelial-mesenchymal transition, leading to enhanced tumor growth and metastasis. These effects of nicotine are mediated through the nicotinic acetylcholine receptors that are expressed on a variety of neuronal and nonneuronal cells. Specific signal transduction cascades that emanate from different nAChR subunits or subunit combinations facilitate the proliferative and prosurvival functions of nicotine. Nicotinic acetylcholine receptors appear to stimulate many downstream signaling cascades induced by growth factors and mitogens. It has been suggested that antagonists of nAChR signaling might have antitumor effects and might open new avenues for combating tobacco-related cancer. This paper examines the historical data connecting nicotine tumor progression and the recent efforts to target the nicotinic acetylcholine receptors to combat cancer.
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39
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Lee J, Cooke JP. The role of nicotine in the pathogenesis of atherosclerosis. Atherosclerosis 2011; 215:281-3. [PMID: 21345436 DOI: 10.1016/j.atherosclerosis.2011.01.003] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Accepted: 01/04/2011] [Indexed: 10/18/2022]
Affiliation(s)
- Jieun Lee
- School of Medicine, Stanford Cardiovascular Institute, Stanford, CA 94305-5406, USA
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40
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Dasgupta P, Rizwani W, Pillai S, Davis R, Banerjee S, Hug K, Lloyd M, Coppola D, Haura E, Chellappan SP. ARRB1-mediated regulation of E2F target genes in nicotine-induced growth of lung tumors. J Natl Cancer Inst 2011; 103:317-33. [PMID: 21212384 DOI: 10.1093/jnci/djq541] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Nicotine induces the proliferation of non-small cell lung cancer (NSCLC) cells via nicotinic acetylcholine receptors and the arrestin, β1 (ARRB1) protein. However, whether ARRB1 translocates to the nucleus upon nicotinic acetylcholine receptor activation and how it regulates growth of human NSCLCs are not known. METHODS We investigated nuclear localization of ARRB1 in human NSCLC cell lines (A549 and H1650), normal lung cell lines (NHBE and SAEC), and lung cancer tissue microarray. A549 cells were transfected with ARRB1-specific short hairpin RNA (A549-sh) to knockdown ARRB1 expression, or with empty vector (A549-EV), to examine the role of ARRB1 in the mitogenic and antiapoptotic effects of nicotine, binding of ARRB1 to E2F transcription factors, and the role of ARRB1 in nicotine-induced expression of E2F-regulated survival and proliferative genes cell division cycle 6 homolog (CDC6), thymidylate synthetase (TYMS), and baculoviral IAP repeat-containing 5 (BIRC5). Real-time polymerase chain reaction was performed for quantitative analysis of mRNA expression. Chromatin immunoprecipitation assays were performed on A549 cells and fresh-frozen human NSCLC tumors (n = 8) to examine the binding of ARRB1, E1A binding protein (EP300), and acetylated histone 3 (Ac-H3) on the E2F-regulated genes. All statistical tests were two-sided. RESULTS Nicotine induced the nuclear translocation of ARRB1 in NSCLC and normal lung cells, and lung tumor tissues from smokers showed an increased nuclear localization. The mitogenic and antiapoptotic effects of nicotine were reduced in A549-sh cells. Nuclear ARRB1 bound to E2F transcription factors in normal lung cells, NSCLC cells, and tumors. Nicotine treatment induced a statistically significant increased expression of E2F-regulated genes in A549-EV but not in A549-sh cells; the maximum difference being observed in BIRC5 (A549-EV vs A549-sh, mean fold-increase in mRNA level upon nicotine treatment = 20.7-fold, 95% confidence interval = 19.2- to 22.2-fold, vs mean = 0.8-fold, 95% confidence interval= 0.78- to 0.82-fold, P < .001). Furthermore, nicotine induced the binding of ARRB1, EP300, and Ac-H3 on E2F-regulated genes. CONCLUSION Nicotine induced the nuclear translocation of ARRB1 and showed increased expression of proliferative and survival genes, thereby contributing to the growth and progression of NSCLCs.
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Affiliation(s)
- Piyali Dasgupta
- Department of Oncologic Sciences, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA
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Dragomir A, Akay YM, Akay M. Modeling carbachol-induced hippocampal network synchronization using hidden Markov models. J Neural Eng 2010; 7:056012. [PMID: 20841638 DOI: 10.1088/1741-2560/7/5/056012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In this work we studied the neural state transitions undergone by the hippocampal neural network using a hidden Markov model (HMM) framework. We first employed a measure based on the Lempel-Ziv (LZ) estimator to characterize the changes in the hippocampal oscillation patterns in terms of their complexity. These oscillations correspond to different modes of hippocampal network synchronization induced by the cholinergic agonist carbachol in the CA1 region of mice hippocampus. HMMs are then used to model the dynamics of the LZ-derived complexity signals as first-order Markov chains. Consequently, the signals corresponding to our oscillation recordings can be segmented into a sequence of statistically discriminated hidden states. The segmentation is used for detecting transitions in neural synchronization modes in data recorded from wild-type and triple transgenic mice models (3xTG) of Alzheimer's disease (AD). Our data suggest that transition from low-frequency (delta range) continuous oscillation mode into high-frequency (theta range) oscillation, exhibiting repeated burst-type patterns, occurs always through a mode resembling a mixture of the two patterns, continuous with burst. The relatively random patterns of oscillation during this mode may reflect the fact that the neuronal network undergoes re-organization. Further insight into the time durations of these modes (retrieved via the HMM segmentation of the LZ-derived signals) reveals that the mixed mode lasts significantly longer (p < 10(-4)) in 3xTG AD mice. These findings, coupled with the documented cholinergic neurotransmission deficits in the 3xTG mice model, may be highly relevant for the case of AD.
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Affiliation(s)
- Andrei Dragomir
- Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, Houston, TX, USA
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42
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Ghiron C, Haydar SN, Aschmies S, Bothmann H, Castaldo C, Cocconcelli G, Comery TA, Di L, Dunlop J, Lock T, Kramer A, Kowal D, Jow F, Grauer S, Harrison B, La Rosa S, Maccari L, Marquis KL, Micco I, Nencini A, Quinn J, Robichaud AJ, Roncarati R, Scali C, Terstappen GC, Turlizzi E, Valacchi M, Varrone M, Zanaletti R, Zanelli U. Novel Alpha-7 Nicotinic Acetylcholine Receptor Agonists Containing a Urea Moiety: Identification and Characterization of the Potent, Selective, and Orally Efficacious Agonist 1-[6-(4-Fluorophenyl)pyridin-3-yl]-3-(4-piperidin-1-ylbutyl) Urea (SEN34625/WYE-103914). J Med Chem 2010; 53:4379-89. [DOI: 10.1021/jm901692q] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chiara Ghiron
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Simon N. Haydar
- Chemical Sciences and Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, New Jersey 08543-8000
| | - Suzan Aschmies
- Chemical Sciences and Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, New Jersey 08543-8000
| | - Hendrick Bothmann
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Cristiana Castaldo
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | | | - Thomas A. Comery
- Chemical Sciences and Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, New Jersey 08543-8000
| | - Li Di
- Chemical Sciences and Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, New Jersey 08543-8000
| | - John Dunlop
- Chemical Sciences and Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, New Jersey 08543-8000
| | - Tim Lock
- Chemical Sciences and Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, New Jersey 08543-8000
| | - Angela Kramer
- Chemical Sciences and Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, New Jersey 08543-8000
| | - Dianne Kowal
- Chemical Sciences and Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, New Jersey 08543-8000
| | - Flora Jow
- Chemical Sciences and Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, New Jersey 08543-8000
| | - Steve Grauer
- Chemical Sciences and Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, New Jersey 08543-8000
| | - Boyd Harrison
- Chemical Sciences and Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, New Jersey 08543-8000
| | - Salvatore La Rosa
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Laura Maccari
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Karen L. Marquis
- Chemical Sciences and Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, New Jersey 08543-8000
| | - Iolanda Micco
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Arianna Nencini
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Joanna Quinn
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Albert J. Robichaud
- Chemical Sciences and Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, New Jersey 08543-8000
| | - Renza Roncarati
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Carla Scali
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Georg C. Terstappen
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Elisa Turlizzi
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Michela Valacchi
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Maurizio Varrone
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Riccardo Zanaletti
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
| | - Ugo Zanelli
- Siena Biotech SpA, Strada del Petriccio e Belriguardo 35, 53100 Siena, Italy
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Main immunogenic region structure promotes binding of conformation-dependent myasthenia gravis autoantibodies, nicotinic acetylcholine receptor conformation maturation, and agonist sensitivity. J Neurosci 2009; 29:13898-908. [PMID: 19890000 DOI: 10.1523/jneurosci.2833-09.2009] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The main immunogenic region (MIR) is a conformation-dependent region at the extracellular apex of alpha1 subunits of muscle nicotinic acetylcholine receptor (AChR) that is the target of half or more of the autoantibodies to muscle AChRs in human myasthenia gravis and rat experimental autoimmune myasthenia gravis. By making chimeras of human alpha1 subunits with alpha7 subunits, both MIR epitopes recognized by rat mAbs and by the patient-derived human mAb 637 to the MIR were determined to consist of two discontiguous sequences, which are adjacent only in the native conformation. The MIR, including loop alpha1 67-76 in combination with the N-terminal alpha helix alpha1 1-14, conferred high-affinity binding for most rat mAbs to the MIR. However, an additional sequence corresponding to alpha1 15-32 was required for high-affinity binding of human mAb 637. A water soluble chimera of Aplysia acetylcholine binding protein with the same alpha1 MIR sequences substituted was recognized by a majority of human, feline, and canine myasthenia gravis sera. The presence of the alpha1 MIR sequences in alpha1/alpha7 chimeras greatly promoted AChR expression and significantly altered the sensitivity to activation. This reveals a structural and functional, as well as antigenic, significance of the MIR.
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Davis R, Rizwani W, Banerjee S, Kovacs M, Haura E, Coppola D, Chellappan S. Nicotine promotes tumor growth and metastasis in mouse models of lung cancer. PLoS One 2009; 4:e7524. [PMID: 19841737 PMCID: PMC2759510 DOI: 10.1371/journal.pone.0007524] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Accepted: 08/25/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Nicotine is the major addictive component of tobacco smoke. Although nicotine is generally thought to have limited ability to initiate cancer, it can induce cell proliferation and angiogenesis in a variety of systems. These properties might enable nicotine to facilitate the growth of tumors already initiated. Here we show that nicotine significantly promotes the progression and metastasis of tumors in mouse models of lung cancer. This effect was observed when nicotine was administered through intraperitoneal injections, or through over-the-counter transdermal patches. METHODS AND FINDINGS In the present study, Line1 mouse adenocarcinoma cells were implanted subcutaneously into syngenic BALB/c mice. Nicotine administration either by intraperitoneal (i.p.) injection or transdermal patches caused a remarkable increase in the size of implanted Line1 tumors. Once the tumors were surgically removed, nicotine treated mice had a markedly higher tumor recurrence (59.7%) as compared to the vehicle treated mice (19.5%). Nicotine also increased metastasis of dorsally implanted Line1 tumors to the lungs by 9 folds. These studies on transplanted tumors were extended to a mouse model where the tumors were induced by the tobacco carcinogen, NNK. Lung tumors were initiated in A/J mice by i.p. injection of NNK; administration of 1 mg/kg nicotine three times a week led to an increase in the size and the number of tumors formed in the lungs. In addition, nicotine significantly reduced the expression of epithelial markers, E-Cadherin and beta-Catenin as well as the tight junction protein ZO-1; these tumors also showed an increased expression of the alpha(7) nAChR subunit. We believe that exposure to nicotine either by tobacco smoke or nicotine supplements might facilitate increased tumor growth and metastasis. CONCLUSIONS Our earlier results indicated that nicotine could induce invasion and epithelial-mesenchymal transition (EMT) in cultured lung, breast and pancreatic cancer cells. This study demonstrates for the first time that administration of nicotine either by i.p. injection or through over-the-counter dermal patches can promote tumor growth and metastasis in immunocompetent mice. These results suggest that while nicotine has only limited capacity to initiate tumor formation, it can facilitate the progression and metastasis of tumors pre-initiated by tobacco carcinogens.
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Affiliation(s)
- Rebecca Davis
- Department of Oncologic Sciences, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, United States of America
| | - Wasia Rizwani
- Department of Oncologic Sciences, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, United States of America
| | - Sarmistha Banerjee
- Department of Oncologic Sciences, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, United States of America
| | - Michelle Kovacs
- Department of Oncologic Sciences, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, United States of America
| | - Eric Haura
- Department of Oncologic Sciences, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, United States of America
| | - Domenico Coppola
- Department of Oncologic Sciences, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, United States of America
| | - Srikumar Chellappan
- Department of Oncologic Sciences, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, United States of America
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Mukherjee J, Kuryatov A, Moss SJ, Lindstrom JM, Anand R. Mutations of cytosolic loop residues impair assembly and maturation of alpha7 nicotinic acetylcholine receptors. J Neurochem 2009; 110:1885-94. [PMID: 19627445 DOI: 10.1111/j.1471-4159.2009.06285.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Mechanisms that regulate early events in the biogenesis of the alpha7 nicotinic acetylcholine receptor (alpha7 AChR) are not well understood. Data presented here show that single amino acid mutations in the cytoplasmic loop of the alpha7 AChR, between position 335 and 343, abolish or attenuate expression of mature pentameric alpha7 AChRs in both human embryonic kidney tsA201 (HEK) and neuronal SH-SY5Y cells. Although the number of mature alpha7 AChRs is increased significantly in the presence of the chaperone protein resistant to inhibitors of cholineesterase-3 in HEK cells, sucrose gradient sedimentation reveals that the vast majority of alpha7 subunits are aggregated or improperly assembled. Transfection of alpha7 AChRs in SH-SY5Y cells, which endogenously express the alpha7 AChR, results in a much larger fraction of subunits assembled into mature AChRs. Thus, efficient assembly of alpha7 AChRs is influenced by several regions of the large cytoplasmic domain, as well perhaps by other parts of its structure, and requires as yet unknown factors not required by other AChR subtypes.
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Affiliation(s)
- Jayanta Mukherjee
- Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA, USA
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Paleari L, Cesario A, Fini M, Russo P. alpha7-Nicotinic receptor antagonists at the beginning of a clinical era for NSCLC and Mesothelioma? Drug Discov Today 2009; 14:822-36. [PMID: 19616116 DOI: 10.1016/j.drudis.2009.06.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 06/25/2009] [Accepted: 06/26/2009] [Indexed: 11/26/2022]
Abstract
Of the human solid cancers, Non-Small Cell Lung Cancer (NSCLC) and Malignant Pleural Mesothelioma (MPM) display a natural history supporting the concept that they develop from multiple preneoplastic pathways. Recently, new evidence suggested that nicotinic Acetylcholine Receptors (nAChRs) play a significant role in lung cancer predisposition and natural history. This review is based on some translational research aimed at evaluating the potential therapeutic effect of nAChR antagonists on NSCLC and MPM. The background and rationale of this approach are based on the experimental observations that: (a) NSCLC and MPM cells express nAChRs and (b) the activation of these receptors by agonists, namely nicotine, inhibits apoptosis, whereas receptor antagonists have a pro-apoptotic effect.
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Affiliation(s)
- Laura Paleari
- Lung Cancer Unit, National Cancer Research Institute, Genoa, Italy.
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Turner M, Eidemiller S, Martin B, Narver A, Marshall J, Zemp L, Cornell KA, McIntosh JM, McDougal OM. Structural basis for alpha-conotoxin potency and selectivity. Bioorg Med Chem 2009; 17:5894-9. [PMID: 19628399 DOI: 10.1016/j.bmc.2009.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 07/02/2009] [Accepted: 07/03/2009] [Indexed: 10/20/2022]
Abstract
Parkinson's disease is a debilitating movement disorder characterized by altered levels of alpha(6)beta(2) * ( * indicates the possible presence of additional subunits) nicotinic acetylcholine receptors (nAChRs) localized on presynaptic striatal catecholaminergic neurons. alpha-Conotoxin MII (alpha-CTx MII) is a highly useful ligand to probe alpha(6)beta(2) nAChRs structure and function, but it does not discriminate among closely related alpha(6) * nAChR subtypes. Modification of the alpha-CTx MII primary sequence led to the identification of alpha-CTx MII[E11A], an analog with 500-5300-fold discrimination between alpha(6) * subtypes found in both human and non-human primates. alpha-CTx MII[E11A] binds most strongly (femtomolar dissociation constant) to the high affinity alpha(6) nAChR, a subtype that is selectively lost in Parkinson's disease. Here, we present the three-dimensional solution structure for alpha-CTx MII[E11A] as determined by two-dimensional (1)H NMR spectroscopy to 0.13+/-0.09A backbone and 0.45+/-0.08A heavy atom root-mean-square deviation from mean structure. Structural comparisons suggest that the increased hydrophobic area of alpha-CTx MII[E11A] relative to other members of the alpha-CTx family may be responsible for its exceptionally high affinity for alpha6alpha4beta2 * nAChR as well as discrimination between alpha(6)beta(2) and alpha(3)beta(2) containing nAChRs. This finding may enable the rational design of novel peptide analogs that demonstrate enhanced specificity for alpha(6) * nAChR subunit interfaces and provide a means to better understand nAChR structural determinants that modulate brain dopamine levels and the pathophysiology of Parkinson's disease.
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Affiliation(s)
- Matt Turner
- Department of Chemistry and Biochemistry, Boise State University, ID 83725-1520, USA
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Akay M, Wang K, Akay YM, Dragomir A, Wu J. Nonlinear dynamical analysis of carbachol induced hippocampal oscillations in mice. Acta Pharmacol Sin 2009; 30:859-67. [PMID: 19498425 DOI: 10.1038/aps.2009.66] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
AIM Hippocampal neuronal network and synaptic impairment underlie learning and memory deficit in Alzheimer's disease (AD) patients and animal models. In this paper, we analyzed the dynamics and complexity of hippocampal neuronal network synchronization induced by acute exposure to carbachol, a nicotinic and muscarinic receptor co-agonist, using the nonlinear dynamical model based on the Lempel-Ziv estimator. We compared the dynamics of hippocampal oscillations between wild-type (WT) and triple-transgenic (3xTg) mice, as an AD animal model. We also compared these dynamic alterations between different age groups (5 and 10 months). We hypothesize that there is an impairment of complexity of CCh-induced hippocampal oscillations in 3xTg AD mice compared to WT mice, and that this impairment is age-dependent. METHODS To test this hypothesis, we used electrophysiological recordings (field potential) in hippocampal slices. RESULTS Acute exposure to 100 micromol/L CCh induced field potential oscillations in hippocampal CA1 region, which exhibited three distinct patterns: (1) continuous neural firing, (2) repeated burst neural firing and (3) the mixed (continuous and burst) pattern in both WT and 3xTg AD mice. Based on Lempel-Ziv estimator, pattern (2) was significantly lower than patterns (1) and (3) in 3xTg AD mice compared to WT mice (P<0.001), and also in 10-month old WT mice compared to those in 5-month old WT mice (P<0.01). CONCLUSION These results suggest that the burst pattern (theta oscillation) of hippocampal network is selectively impaired in 3xTg AD mouse model, which may reflect a learning and memory deficit in the AD patients.
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Haydar SN, Ghiron C, Bettinetti L, Bothmann H, Comery TA, Dunlop J, La Rosa S, Micco I, Pollastrini M, Quinn J, Roncarati R, Scali C, Valacchi M, Varrone M, Zanaletti R. SAR and biological evaluation of SEN12333/WAY-317538: Novel alpha 7 nicotinic acetylcholine receptor agonist. Bioorg Med Chem 2009; 17:5247-58. [PMID: 19515567 DOI: 10.1016/j.bmc.2009.05.040] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 05/08/2009] [Accepted: 05/14/2009] [Indexed: 10/20/2022]
Abstract
Alpha 7 nicotinic acetylcholine receptor (alpha(7) nAChR) agonists are promising therapeutic candidates for the treatment of cognitive impairment associated with a variety of disorders including Alzheimer's disease and schizophrenia. Alpha 7 nAChRs are expressed in brain regions associated with cognitive function, regulate cholinergic neurotransmission and have been shown to be down regulated in both schizophrenia and Alzheimer's disease. Herein we report a novel, potent small molecule agonist of the alpha 7 nAChR, SEN12333/WAY-317538. This compound is a selective agonist of the alpha(7) nAChR with excellent in vitro and in vivo profiles, excellent brain penetration and oral bioavailability, and demonstrates in vivo efficacy in multiple behavioural cognition models. The SAR and biological evaluation of this series of compounds are discussed.
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Affiliation(s)
- Simon N Haydar
- Chemical Sciences and Neuroscience Discovery Research, Wyeth Research, CN 8000, Princeton, NJ 08543-8000, USA.
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Cooke JP, Ghebremariam YT. Endothelial nicotinic acetylcholine receptors and angiogenesis. Trends Cardiovasc Med 2009; 18:247-53. [PMID: 19232953 DOI: 10.1016/j.tcm.2008.11.007] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Revised: 11/18/2008] [Accepted: 11/20/2008] [Indexed: 10/21/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) were first described in non-excitable cells just more than a decade ago. The nAChRs on endothelial cells modulate key angiogenic processes, including endothelial cell survival, proliferation, and migration. The receptors may be stimulated by endogenous agonists such as acetylcholine, or exogenous chemicals such as nicotine, to activate physiologic angiogenesis (such as in wound healing) or pathologic angiogenesis (such as retinal neovascularization or tumor angiogenesis). The endothelial nAChRs may represent a target for therapeutic modulation of disorders characterized by insufficient or pathologic angiogenesis.
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Affiliation(s)
- John P Cooke
- Division of Cardiovascular Medicine, Stanford University, Stanford, CA 94305, USA.
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