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Ding ZM, Neslund EM, Sun D, Tan X. Methoxsalen inhibits the acquisition of nicotine self-administration: attenuation by cotinine replacement in male rats. Nicotine Tob Res 2024:ntae063. [PMID: 38513068 DOI: 10.1093/ntr/ntae063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Indexed: 03/23/2024]
Abstract
INTRODUCTION Cigarette smoking remains the leading preventable cause of disease and death. Nicotine is the primary reinforcing ingredient in cigarettes sustaining addiction. Cotinine is the major metabolite of nicotine that produces a myriad of neurobehavioral effects. Previous studies showed that cotinine supported self-administration in rats and rats with a history of cotinine self-administration exhibited relapse-like drug-seeking behavior, suggesting that cotinine may also be reinforcing. To date, whether cotinine may contribute to nicotine reinforcement remains unknown. Nicotine metabolism is mainly catalyzed by hepatic CYP2B1/2 enzymes in rats and methoxsalen is a potent CYP2B1/2 inhibitor. METHODS The study examined nicotine metabolism, self-administration, and locomotor activity. The hypothesis is that methoxsalen inhibits nicotine self-administration and cotinine replacement attenuates the inhibitory effects of methoxsalen in male rats. RESULTS Methoxsalen decreased plasma cotinine levels following a subcutaneous nicotine injection. Repeated daily methoxsalen treatments reduced the acquisition of nicotine self-administration, leading to fewer nicotine infusions, lower nicotine intake, and lower plasma cotinine levels. However, methoxsalen did not alter the maintenance of nicotine self-administration despite a significant reduction of plasma cotinine levels. Cotinine replacement by mixing cotinine with nicotine for self-administration dose-dependently increased plasma cotinine levels and enhanced the acquisition of self-administration. Neither basal nor nicotine-induced locomotor activity was altered by methoxsalen. CONCLUSIONS These results indicate that methoxsalen inhibition of cotinine formation impaired the acquisition of nicotine self-administration, and cotinine replacement attenuated the inhibitory effects of methoxsalen on the acquisition of self-administration, suggesting that cotinine may contribute to the initial development of nicotine reinforcement. IMPLICATIONS Smoking cessation medications targeting nicotine's effects are only moderately effective, making it imperative to better understand the mechanisms of nicotine misuse. Methoxsalen inhibited nicotine metabolism to cotinine and impaired the acquisition of nicotine self-administration. Cotinine replacement restored plasma cotinine and attenuated the methoxsalen inhibition of nicotine self-administration in rats. These results suggest that (1) the inhibition of nicotine metabolism may be a viable strategy in reducing the development of nicotine reinforcement, (2) methoxsalen may be translationally valuable, and (3) cotinine may be a potential pharmacological target for therapeutic development given its important role in the initial development of nicotine reinforcement.
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Affiliation(s)
- Zheng-Ming Ding
- Department of Anesthesiology & Perioperative Medicine, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
- Department of Pharmacology, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Elizabeth M Neslund
- Department of Anesthesiology & Perioperative Medicine, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Dongxiao Sun
- Department of Pharmacology, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
- Penn State Mass Spectrometry Core Facility, Penn State University College of Medicine, Hershey, PA 17033, USA
| | - Xiaoying Tan
- Department of Anesthesiology & Perioperative Medicine, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
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Ding ZM, Neslund EM, Sun D, Tan X. Methoxsalen inhibited the acquisition of nicotine self-administration: attenuation by cotinine replacement in rats. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.04.543614. [PMID: 37333320 PMCID: PMC10274622 DOI: 10.1101/2023.06.04.543614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Cigarette smoking remains the leading preventable cause of disease and death. Nicotine is the primary reinforcing ingredient in cigarettes sustaining addiction. Cotinine is the major metabolite of nicotine that produces a myriad of neurobehavioral effects. Cotinine supported self-administration and rats with a history of intravenous self-administration of cotinine exhibited relapse-like drug-seeking behavior, suggesting cotinine may also be reinforcing. To date, a potential contribution of cotinine to nicotine reinforcement remains unknown. Nicotine metabolism is mainly catalyzed by hepatic CYP2B1 enzyme in the rat and methoxsalen is a potent CYP2B1 inhibitor. The study tested the hypothesis that methoxsalen inbibits nicotine metabolism and self-administration, and that cotinine replacement attenuates the inhibitory effects of methoxsalen. Acute methoxsalen decreased plasma cotinine levels and increased nicotine levels following subcutaneous nicotine injection. Repeated methoxsalen reduced the acquisition of nicotine self-administration, leading to fewer nicotine infusions, disruption of lever differentiation, smaller total nicotine intake, and lower plasma cotinine levels. On the other hand, methoxsalen did not alter nicotine self-administration during the maintenance phase despite great reduction of plasma cotinine levels. Cotinine replacement by mixing cotinine with nicotine for self-administration dose-dependently increased plasma cotinine levels, counteracted effects of methoxsalen, and enhanced the acquisition of self-administration. Neither basal nor nicotine-induced locomotor activity was altered by methoxsalen. These results indicate that methoxsalen depressed cotinine formation from nicotine and the acquisition of nicotine self-administration, and that replacement of plasma cotinine attenuated the inhibitory effects of methoxsalen, suggesting that cotinine may contribute to the development of nicotine reinforcement.
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Affiliation(s)
- Zheng-Ming Ding
- Department of Anesthesiology & Perioperative Medicine, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
- Department of Pharmacology, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Elizabeth M. Neslund
- Department of Anesthesiology & Perioperative Medicine, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Dongxiao Sun
- Department of Pharmacology, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
- Penn State Mass Spectrometry Core Facility, Penn State University College of Medicine, Hershey, PA 17033, USA
| | - Xiaoying Tan
- Department of Anesthesiology & Perioperative Medicine, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
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Bastianini S, Lo Martire V, Alvente S, Berteotti C, Matteoli G, Rullo L, Stamatakos S, Silvani A, Candeletti S, Romualdi P, Cohen G, Zoccoli G. Early-life nicotine or cotinine exposure produces long-lasting sleep alterations and downregulation of hippocampal corticosteroid receptors in adult mice. Sci Rep 2021; 11:23897. [PMID: 34903845 PMCID: PMC8668915 DOI: 10.1038/s41598-021-03468-5] [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: 07/07/2021] [Accepted: 11/30/2021] [Indexed: 11/24/2022] Open
Abstract
Early-life exposure to environmental toxins like tobacco can permanently re-program body structure and function. Here, we investigated the long-term effects on mouse adult sleep phenotype exerted by early-life exposure to nicotine or to its principal metabolite, cotinine. Moreover, we investigated whether these effects occurred together with a reprogramming of the activity of the hippocampus, a key structure to coordinate the hormonal stress response. Adult male mice born from dams subjected to nicotine (NIC), cotinine (COT) or vehicle (CTRL) treatment in drinking water were implanted with electrodes for sleep recordings. NIC and COT mice spent significantly more time awake than CTRL mice at the transition between the rest (light) and the activity (dark) period. NIC and COT mice showed hippocampal glucocorticoid receptor (GR) downregulation compared to CTRL mice, and NIC mice also showed hippocampal mineralocorticoid receptor downregulation. Hippocampal GR expression significantly and inversely correlated with the amount of wakefulness at the light-to-dark transition, while no changes in DNA methylation were found. We demonstrated that early-life exposure to nicotine (and cotinine) concomitantly entails long-lasting reprogramming of hippocampal activity and sleep phenotype suggesting that the adult sleep phenotype may be modulated by events that occurred during that critical period of life.
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Affiliation(s)
- Stefano Bastianini
- grid.6292.f0000 0004 1757 1758PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna, Piazza di Porta San Donato 2, 40126 Bologna, Italy
| | - Viviana Lo Martire
- grid.6292.f0000 0004 1757 1758PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna, Piazza di Porta San Donato 2, 40126 Bologna, Italy
| | - Sara Alvente
- grid.6292.f0000 0004 1757 1758PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna, Piazza di Porta San Donato 2, 40126 Bologna, Italy
| | - Chiara Berteotti
- grid.6292.f0000 0004 1757 1758PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna, Piazza di Porta San Donato 2, 40126 Bologna, Italy
| | - Gabriele Matteoli
- grid.6292.f0000 0004 1757 1758PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna, Piazza di Porta San Donato 2, 40126 Bologna, Italy
| | - Laura Rullo
- grid.6292.f0000 0004 1757 1758Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Serena Stamatakos
- grid.6292.f0000 0004 1757 1758Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Alessandro Silvani
- grid.6292.f0000 0004 1757 1758PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna, Piazza di Porta San Donato 2, 40126 Bologna, Italy
| | - Sanzio Candeletti
- grid.6292.f0000 0004 1757 1758Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Patrizia Romualdi
- grid.6292.f0000 0004 1757 1758Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Gary Cohen
- grid.4714.60000 0004 1937 0626Department of Women and Child Health, Karolinska Institutet, Stockholm, Sweden ,grid.412703.30000 0004 0587 9093Centre for Sleep Health and Research, Sleep Investigation Laboratory, Royal North Shore Hospital, Sydney, Australia
| | - Giovanna Zoccoli
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna, Piazza di Porta San Donato 2, 40126, Bologna, Italy.
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Tan X, Vrana K, Ding ZM. Cotinine: Pharmacologically Active Metabolite of Nicotine and Neural Mechanisms for Its Actions. Front Behav Neurosci 2021; 15:758252. [PMID: 34744656 PMCID: PMC8568040 DOI: 10.3389/fnbeh.2021.758252] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 09/27/2021] [Indexed: 11/17/2022] Open
Abstract
Tobacco use disorder continues to be a leading public health issue and cause of premature death in the United States. Nicotine is considered as the major tobacco alkaloid causing addiction through its actions on nicotinic acetylcholine receptors (nAChRs). Current pharmacotherapies targeting nicotine's effects produce only modest effectiveness in promoting cessation, highlighting the critical need for a better understanding of mechanisms of nicotine addiction to inform future treatments. There is growing interest in identifying potential contributions of non-nicotine components to tobacco reinforcement. Cotinine is a minor alkaloid, but the major metabolite of nicotine that can act as a weak agonist of nAChRs. Accumulating evidence indicates that cotinine produces diverse effects and may contribute to effects of nicotine. In this review, we summarize findings implicating cotinine as a neuroactive metabolite of nicotine and discuss available evidence regarding potential mechanisms underlying its effects. Preclinical findings reveal that cotinine crosses the blood brain barrier and interacts with both nAChRs and non-nAChRs in the nervous system, and produces neuropharmacological and behavioral effects. Clinical studies suggest that cotinine is psychoactive in humans. However, reviewing evidence regarding mechanisms underlying effects of cotinine provides a mixed picture with a lack of consensus. Therefore, more research is warranted in order to provide better insight into the actions of cotinine and its contribution to tobacco addiction.
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Affiliation(s)
- Xiaoying Tan
- Department of Anesthesiology & Perioperative Medicine, and Pharmacology, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Kent Vrana
- Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Zheng-Ming Ding
- Department of Anesthesiology & Perioperative Medicine, and Pharmacology, Pennsylvania State University College of Medicine, Hershey, PA, United States
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Ding ZM, Gao Y, Sentir AM, Tan X. Self-Administration of Cotinine in Wistar Rats: Comparisons to Nicotine. J Pharmacol Exp Ther 2020; 376:338-347. [PMID: 33361363 DOI: 10.1124/jpet.120.000367] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022] Open
Abstract
Nicotine is the major addictive component in tobacco. Cotinine is the major metabolite of nicotine and a weak agonist for nicotinic acetylcholine receptors (nAChRs). Nicotine supports self-administration in rodents. However, it remains undetermined whether cotinine can be self-administered. This study aimed to characterize cotinine self-administration in rats, to compare effects of cotinine to those of nicotine, and to determine potential involvement of nAChRs in cotinine's effects. Adult Wistar rats were trained to self-administer cotinine or nicotine (0.0075, 0.015, 0.03, or 0.06 mg/kg per infusion) under fixed-ratio (FR) and progressive-ratio (PR) schedules. Blood nicotine and cotinine levels were determined after the last FR session. Effects of mecamylamine, a nonselective nAChR antagonist, and varenicline, a partial agonist for α4β2* nAChRs, on cotinine and nicotine self-administration were determined. Rats readily acquired cotinine self-administration, responded more on active lever, and increased motivation to self-administer cotinine when the reinforcement requirement increased. Blood cotinine levels ranged from 77 to 792 ng/ml. Nicotine induced more infusions at lower doses during FR schedules and greater breakpoints at higher doses during the PR schedule than cotinine. There was no difference in cotinine self-administration between male and female rats. Mecamylamine and varenicline attenuated nicotine but not cotinine self-administration. These results indicate that cotinine was self-administered by rats. These effects of cotinine were less robust than nicotine and exhibited no sex difference. nAChRs appeared to be differentially involved in self-administration of nicotine and cotinine. These results suggest cotinine may play a role in the development of nicotine use and misuse. SIGNIFICANCE STATEMENT: Nicotine addiction is a serious public health problem. Cotinine is the major metabolite of nicotine, but its involvement in nicotine reinforcement remains elusive. Our findings indicate that cotinine, at doses producing clinically relevant blood cotinine levels, supported intravenous self-administration in rats. Cotinine self-administration was less robust than nicotine. Mecamylamine and varenicline attenuated nicotine but not cotinine self-administration. These results suggest cotinine may play a role in the development of nicotine use and misuse.
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Affiliation(s)
- Zheng-Ming Ding
- Department of Anesthesiology and Perioperative Medicine, and Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania (Z.-M.D., X.T.) and Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana (Y.G., A.S.)
| | - Yong Gao
- Department of Anesthesiology and Perioperative Medicine, and Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania (Z.-M.D., X.T.) and Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana (Y.G., A.S.)
| | - Alena M Sentir
- Department of Anesthesiology and Perioperative Medicine, and Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania (Z.-M.D., X.T.) and Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana (Y.G., A.S.)
| | - Xiaoying Tan
- Department of Anesthesiology and Perioperative Medicine, and Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania (Z.-M.D., X.T.) and Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana (Y.G., A.S.)
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Pardo M, Beurel E, Jope RS. Cotinine administration improves impaired cognition in the mouse model of Fragile X syndrome. Eur J Neurosci 2016; 45:490-498. [PMID: 27775852 DOI: 10.1111/ejn.13446] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 10/19/2016] [Accepted: 10/20/2016] [Indexed: 01/15/2023]
Abstract
Cotinine is the major metabolite of nicotine and has displayed some capacity for improving cognition in mouse models following chronic administration. We tested if acute cotinine treatment is capable of improving cognition in the mouse model of Fragile X syndrome, Fmr1-/- knockout mice, and if this is related to inhibition by cotinine treatment of glycogen synthase kinase-3β (GSK3β), which is abnormally active in Fmr1-/- mice. Acute cotinine treatment increased the inhibitory serine-phosphorylation of GSK3β and the activating phosphorylation of AKT, which can mediate serine-phosphorylation of GSK3β, in both wild-type and Fmr1-/- mouse hippocampus. Acute cotinine treatment improved cognitive functions of Fmr1-/- mice in coordinate and categorical spatial processing, novel object recognition, and temporal ordering. However, cotinine failed to restore impaired cognition in GSK3β knockin mice, in which a serine9-to-alanine9 mutation blocks the inhibitory serine phosphorylation of GSK3β, causing GSK3β to be hyperactive. These results indicate that acute cotinine treatment effectively repairs impairments of these four cognitive tasks in Fmr1-/- mice, and suggest that this cognition-enhancing effect of cotinine is linked to its induction of inhibitory serine-phosphorylation of GSK3. Taken together, these results show that nicotinic receptor agonists can act as cognitive enhancers in a mouse model of Fragile X syndrome and highlight the potential role of inhibiting GSK3β in mediating the beneficial effects of cotinine on memory.
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Affiliation(s)
- Marta Pardo
- Department of Psychiatry and Behavioral Sciences, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA.,Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Eleonore Beurel
- Department of Psychiatry and Behavioral Sciences, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA.,Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Richard S Jope
- Department of Psychiatry and Behavioral Sciences, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA.,Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, USA
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Biochemical, kinetic, and in silico characterization of DING protein purified from probiotic lactic acid bacteria Pediococcus acidilactici NCDC 252. Appl Biochem Biotechnol 2014; 175:1092-110. [PMID: 25367285 DOI: 10.1007/s12010-014-1306-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 10/15/2014] [Indexed: 01/12/2023]
Abstract
DING proteins are intriguing proteins characterized by conserved N-terminal sequence. In spite of unusually high sequence conservation even between distantly related species, DING proteins exhibit outstanding functional diversity. An extracellular caseinolytic alkaline enzyme was purified to homogeneity from a probiotic lactic acid bacteria Pediococcus acidilactici NCDC 252 using a simple procedure involving ammonium sulphate precipitation and gel filtration chromatography. This was purified 45.72-fold with a yield and specific activity of 43.5 % and 250 U/mg, respectively. The calculated molecular weight was 38.7 and 38.9 kDa by MALDI and SDS-PAGE, respectively, and pI was 7.77. The enzyme exhibited optimal activity at pH 8.0 and 40 °C. It was considerably stable up to pH 12. For casein, the enzyme had K m of 20 μM with V max of 26 U/ml. The enzyme was resistant to organic solvents but sensitive to DTNB and EDTA that confirmed it as thiol protein with involvement of metal ions in catalysis. Its tryptic peptide fragments showed 95 % similarity with eukaryotic DING, i.e., human phosphate binding protein (HPBP). Homology-based structure evaluation using HBPB as template revealed both to be structurally conserved and also possessing conserved phosphate binding motifs.
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Grizzell JA, Iarkov A, Holmes R, Mori T, Echeverria V. Cotinine reduces depressive-like behavior, working memory deficits, and synaptic loss associated with chronic stress in mice. Behav Brain Res 2014; 268:55-65. [DOI: 10.1016/j.bbr.2014.03.047] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/28/2014] [Accepted: 03/31/2014] [Indexed: 12/21/2022]
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Moran VE. Cotinine: Beyond that Expected, More than a Biomarker of Tobacco Consumption. Front Pharmacol 2012; 3:173. [PMID: 23087643 PMCID: PMC3467453 DOI: 10.3389/fphar.2012.00173] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 09/10/2012] [Indexed: 12/15/2022] Open
Abstract
A greater incidence of tobacco consumption occurs among individuals with psychiatric conditions including post-traumatic stress disorder (PTSD), bipolar disorder, major depression, and schizophrenia, compared with the general population. Even when still controversial, it has been postulated that smoking is a form of self-medication that reduces psychiatric symptoms among individuals with these disorders. To better understand the component(s) of tobacco-inducing smoking behavior, greater attention has been directed toward nicotine. However, in recent years, new evidence has shown that cotinine, the main metabolite of nicotine, exhibits beneficial effects over psychiatric symptoms and may therefore promote smoking within this population. Some of the behavioral effects of cotinine compared to nicotine are discussed here. Cotinine, which accumulates in the body as a result of tobacco exposure, crosses the blood-brain barrier and has different pharmacological properties compared with nicotine. Cotinine has a longer plasma half-life than nicotine and showed no addictive or cardiovascular effects in humans. In addition, at the preclinical level, cotinine facilitated the extinction of fear memory and anxiety after fear conditioning, improved working memory in a mouse model of Alzheimer’s disease (AD) and in a monkey model of schizophrenia. Altogether, the new evidence suggests that the pharmacological and behavioral effects of cotinine may play a key role in promoting tobacco smoking in individuals that suffer from psychiatric conditions and represents a new potential therapeutic agent against psychiatric conditions such as AD and PTSD.
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Affiliation(s)
- Valentina Echeverria Moran
- Research and Development, Department of Veterans Affairs, Bay Pines VA Healthcare System Bay Pines, FL, USA ; Tampa VA Healthcare System Tampa, FL, USA ; Department of Molecular Medicine, University of South Florida Tampa, FL, USA
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Type II-dependent secretion of a Pseudomonas aeruginosa DING protein. Res Microbiol 2012; 163:457-69. [PMID: 22835944 DOI: 10.1016/j.resmic.2012.07.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 07/16/2012] [Indexed: 11/24/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic bacterial pathogen that uses a wide range of protein secretion systems to interact with its host. Genes encoding the PAO1 Hxc type II secretion system are linked to genes encoding phosphatases (LapA/LapB). Microarray genotyping suggested that Pseudomonas aeruginosa clinical isolates, including urinary tract (JJ692) and blood (X13273) isolates, lacked the lapA/lapB genes. Instead, we show that they carry a gene encoding a protein of the PstS family. This protein, which we call LapC, also has significant similarities with LapA/LapB. LapC belongs to the family of DING proteins and displays the canonical DINGGG motif within its N terminus. DING proteins are members of a prokaryotic phosphate binding protein superfamily. We show that LapC is secreted in an Hxc-dependent manner and is under the control of the PhoB response regulator. The genetic organization hxc-lapC found in JJ692 and X13273 is similar to PA14, which is the most frequent P. aeruginosa genotype. While the role of LapA, LapB and LapC proteins remains unclear in P. aeruginosa pathogenesis, they are likely to be part of a phosphate scavenging or sensing system needed to survive and thrive when low phosphate environments are encountered within the host.
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Echeverria V, Zeitlin R. Cotinine: a potential new therapeutic agent against Alzheimer's disease. CNS Neurosci Ther 2012; 18:517-23. [PMID: 22530628 DOI: 10.1111/j.1755-5949.2012.00317.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Tobacco smoking has been correlated with a lower incidence of Alzheimer's disease (AD). This negative correlation has been attributed to nicotine's properties. However, the undesired side-effects of nicotine and the absence of clear evidence of positive effects of this drug on the cognitive abilities of AD patients have decreased the enthusiasm for its therapeutic use. In this review, we discuss evidence showing that cotinine, the main metabolite of nicotine, has many of the beneficial effects but none of the negative side-effects of its precursor. Cotinine has been shown to be neuroprotective, to improve memory in primates as well as to prevent memory loss, and to lower amyloid-beta (Aβ)) burden in AD mice. In AD, cotinine's positive effect on memory is associated with the inhibition of Aβ aggregation, the stimulation of pro-survival factors such as Akt, and the inhibition of pro-apoptotic factors such as glycogen synthase kinase 3 beta (GSK3β). Because stimulation of the α7 nicotinic acetylcholine receptors (α7nAChRs) positively modulates these factors and memory, the involvement of these receptors in cotinine's effects are discussed. Because of its beneficial effects on brain function, good safety profile, and nonaddictive properties, cotinine may represent a new therapeutic agent against AD.
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Gärtner C, Ziegelhöffer B, Kostelka M, Stepan H, Mohr FW, Dhein S. Knock-down of endothelial connexins impairs angiogenesis. Pharmacol Res 2011; 65:347-57. [PMID: 22154844 DOI: 10.1016/j.phrs.2011.11.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 11/22/2011] [Accepted: 11/22/2011] [Indexed: 02/07/2023]
Abstract
Connexins (Cx) are suggested to play important roles in growth and differentiation. Aim of our study was to investigate the role of endothelial Cx in the angiogenic process. Several parameters of angiogenesis were assessed in 18 h Matrigel in vitro angiogenesis assays with human umbilical vein endothelial cells (HUVEC). Prior to culture on Matrigel cells were treated with nicotine or the gap junction inhibitor palmitoleic acid (PA), or siRNA-knock-down of either Cx37, Cx40 or Cx43 was performed. Changes in Cx expression and their effects on gap-junctional communication were investigated using immunofluorescence microscopy, Western blot and Lucifer Yellow dye transfer. Knock-down of each Cx-isoform significantly reduced the amount of specific Cx protein in HUVEC. Cx-knock-down as well as treatment with PA impaired intercellular communication via gap junctions and diminished significantly the number of capillary branches. Knock-down of Cx43 and Cx40 or treatment with PA reduced complexity pattern in the angiogenesis assay. Nicotine significantly reduced expression of Cx43 and Cx37 as well as average length of capillary branches, number of branches and pattern in the Matrigel assay. We can conclude that connexins are involved in angiogenesis, in particular in branch formation. This can partly explain the changes in angiogenesis seen under nicotine treatment.
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Affiliation(s)
- Christiane Gärtner
- Department of Cardiac Surgery, Heart Centre Leipzig, University of Leipzig, Struempellstr. 39, 04289 Leipzig, Germany
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Bookland MJ, Darbinian N, Weaver M, Amini S, Khalili K. Growth inhibition of malignant glioblastoma by DING protein. J Neurooncol 2011; 107:247-56. [PMID: 22052333 DOI: 10.1007/s11060-011-0743-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Accepted: 10/20/2011] [Indexed: 11/25/2022]
Abstract
Malignant gliomas are a highly aggressive type of brain tumor with extremely poor prognosis. These tumors are highly invasive and are often surgically incurable and resistant to chemotherapeutics and radiotherapy. Thus, novel therapies that target pathways involved in growth and survival of the tumor cells are required for the treatment of this class of brain tumors. Previous studies revealed that epidermal growth factor receptor and extracellular-signal-regulated kinases (ERKs), which are involved in the induction of cell proliferation, are activated in the most aggressive type of glioma, i.e. glioblastoma multiforme (GBM). In fact, GBMs with increased levels of ERK activity exhibit a more aggressive phenotype than the others with moderate ERK activity, pointing to the importance of ERK and its kinase activity in the development and progression of these tumors. In this study, we have evaluated the effect of p38SJ, a novel member of the DING family of proteins, derived from Hypericum perforatum calluses, on the growth of malignant glioma cell lines, T98G and U-87MG by focusing on cell cycle and signaling pathways controlled by phosphorylation of various regulatory proteins including ERK. p38SJ, which exhibits profound phosphatase activity, shows the capacity to affect the phosphorylation status of several important kinases modulating signaling pathways, and cell growth and proliferation. Our results demonstrate that p38SJ reduces glioma cell viability and arrests cell cycle progression at G0/G1. The observed growth inhibitory effect of p38SJ is likely mediated by the downregulation of several cell cycle gatekeeper proteins, including cyclin E, Cdc2, and E2F-1. These results suggest that p38SJ may serve as a potential candidate for development of a therapeutic agent for the direct treatment of malignant gliomas and/or as a potential radiosensitizer.
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Affiliation(s)
- Markus J Bookland
- Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Room 741 MERB, 3500 North Broad St., Philadelphia, PA 19140, USA
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14
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Hauser SR, Getachew B, Oster SM, Dhaher R, Ding ZM, Bell RL, McBride WJ, Rodd ZA. Nicotine modulates alcohol-seeking and relapse by alcohol-preferring (P) rats in a time-dependent manner. Alcohol Clin Exp Res 2011; 36:43-54. [PMID: 21689122 DOI: 10.1111/j.1530-0277.2011.01579.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Alcohol is frequently co-abused with smoking. In humans, nicotine use can increase alcohol craving and consumption. The objectives of the current study were to assess the acute effects of nicotine on alcohol seeking and relapse at 2 different time points. METHODS Adult female alcohol-preferring (P) rats were trained in 2-lever operant chambers to self-administer 15% ethanol (EtOH) (v/v) and water on a concurrent fixed-ratio 5-fixed-ratio 1 (FR5-FR1) schedule of reinforcement in daily 1-hour sessions. Following 10 weeks of daily 1-hour sessions, rats underwent 7 extinction sessions, followed by 2 weeks in their home cages. Rats were then returned to the operant chambers without EtOH or water being present for 4 sessions (Pavlovian Spontaneous Recovery [PSR]). Rats were then given a week in their home cage before being returned to the operant chambers with access to EtOH and water (relapse). Nicotine (0, 0.1, 0.3, or 1.0 mg/kg) was injected subcutaneously immediately or 4 hours prior to PSR or relapse testing. RESULTS Injections of nicotine immediately prior to testing reduced (5 to 10 responses PSR; 50 to 60 responses relapse), whereas injections of nicotine 4 hours prior to testing increased (up to 150 responses for PSR; up to 400 responses for relapse with 1.0 mg/kg dose) responses on the EtOH lever during PSR and relapse tests. CONCLUSIONS The results of this study demonstrate that acute effects of nicotine on EtOH-seeking and relapse behaviors may be time dependent, with the immediate effects being a result of nicotine possibly acting as a substitute for EtOH, whereas with a delay of 4 hours, priming effects of nicotine alterations in nicotinic receptors, and/or the effects of nicotine's metabolites (i.e., cotinine and nornicotine) may enhance the expression of EtOH-seeking and relapse behaviors.
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Affiliation(s)
- Sheketha R Hauser
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indiana University-Purdue University at Indianapolis, 46202-4887, USA.
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15
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Collombet JM, Elias M, Gotthard G, Four E, Renault F, Joffre A, Baubichon D, Rochu D, Chabrière E. Eukaryotic DING proteins are endogenous: an immunohistological study in mouse tissues. PLoS One 2010; 5:e9099. [PMID: 20161715 PMCID: PMC2817009 DOI: 10.1371/journal.pone.0009099] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 01/20/2010] [Indexed: 11/19/2022] Open
Abstract
Background DING proteins encompass an intriguing protein family first characterized by their conserved N-terminal sequences. Some of these proteins seem to have key roles in various human diseases, e.g., rheumatoid arthritis, atherosclerosis, HIV suppression. Although this protein family seems to be ubiquitous in eukaryotes, their genes are consistently lacking from genomic databases. Such a lack has considerably hampered functional studies and has fostered therefore the hypothesis that DING proteins isolated from eukaryotes were in fact prokaryotic contaminants. Principal Findings In the framework of our study, we have performed a comprehensive immunological detection of DING proteins in mice. We demonstrate that DING proteins are present in all tissues tested as isoforms of various molecular weights (MWs). Their intracellular localization is tissue-dependant, being exclusively nuclear in neurons, but cytoplasmic and nuclear in other tissues. We also provide evidence that germ-free mouse plasma contains as much DING protein as wild-type. Significance Hence, data herein provide a valuable basis for future investigations aimed at eukaryotic DING proteins, revealing that these proteins seem ubiquitous in mouse tissue. Our results strongly suggest that mouse DING proteins are endogenous. Moreover, the determination in this study of the precise cellular localization of DING proteins constitute a precious evidence to understand their molecular involvements in their related human diseases.
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Affiliation(s)
- Jean-Marc Collombet
- Département de Toxicologie, Institut de Recherche Biomédicale des Armées, Centre de Recherche du Service de Santé des Armées, La Tronche, France
| | - Mikael Elias
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique-Aix Marseille Université, Marseille, France
| | - Guillaume Gotthard
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique-Aix Marseille Université, Marseille, France
| | - Elise Four
- Département de Toxicologie, Institut de Recherche Biomédicale des Armées, Centre de Recherche du Service de Santé des Armées, La Tronche, France
| | - Frédérique Renault
- Département de Toxicologie, Institut de Recherche Biomédicale des Armées, Centre de Recherche du Service de Santé des Armées, La Tronche, France
| | - Aurélie Joffre
- Service de Microscopie et d'Imagerie Médicale, Institut de Recherche Biomédicale des Armées, Centre de Recherche du Service de Santé des Armées, La Tronche, France
| | - Dominique Baubichon
- Département de Toxicologie, Institut de Recherche Biomédicale des Armées, Centre de Recherche du Service de Santé des Armées, La Tronche, France
| | - Daniel Rochu
- Département de Toxicologie, Institut de Recherche Biomédicale des Armées, Centre de Recherche du Service de Santé des Armées, La Tronche, France
| | - Eric Chabrière
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique-Aix Marseille Université, Marseille, France
- * E-mail:
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16
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Amini S, Merabova N, Khalili K, Darbinian N. p38SJ, a novel DINGG protein protects neuronal cells from alcohol induced injury and death. J Cell Physiol 2009; 221:499-504. [PMID: 19739100 DOI: 10.1002/jcp.21903] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Ethanol induces neuronal cell injury and death by dysregulating several signaling events that are controlled, in part, by activation of MAPK/ERK1/2 and/or inactivation of its corresponding phosphatase, PP1. Recently, we have purified a novel protein of 38 kDa in size, p38SJ, from a callus culture of Hypericum perforatum, which belongs to an emerging DINGG family of proteins with phosphate binding activity. Here, we show that treatment of neuronal cells with p38SJ protects cells against injury induced by exposure to ethanol. Furthermore, pre-treatment of neuronal cells with p38SJ diminishes the level of the pro-apoptotic protein Bax and some events associated with apoptosis such as caspase 3 cleavage. In addition, by inducing stress, alcohol can elevate production of reactive oxygen species (ROS) that leads to a decrease in the activity of superoxide dismutase (SOD). Our results showed that p38SJ restores the activity of SOD in the ethanol treated neuronal cells. These observations provide a novel biological tool for developing new approaches for preventing neuronal cell death induced by ethanol and possibly treatment of neurological disorders associated with alcohol abuse.
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Affiliation(s)
- Shohreh Amini
- Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Philadelphia, Pennsylvania 19122, USA.
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17
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Darbinian N, Czernik M, Darbinyan A, Elias M, Chabriere E, Bonasu S, Khalili K, Amini S. Evidence for phosphatase activity of p27SJ and its impact on the cell cycle. J Cell Biochem 2009; 107:400-7. [PMID: 19343785 DOI: 10.1002/jcb.22135] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
p27SJ, a novel protein isolated from St John's wort (Hypericum perforatum), belongs to an emerging family of DING proteins that are related to a prokaryotic phosphate-binding protein superfamily. Here we demonstrate that p27SJ exhibits phosphatase activity and that its expression in cells decreases the level of phosphorylated Erk1/2, a key protein of several signaling pathways. Treatment of p27SJ-expressing cells with phosphatase inhibitors including okadaic acid, maintained Erk1/2 in its phosphorylated form, suggesting that dephosphorylation of Erk1/2 is mediated by p27SJ. Further, expression of p27SJ affects Erk1/2 downstream regulatory targets such as STAT3 and CREB. Moreover, the level of expression of cyclin A that associates with active ERK1/2 and is regulated by CREB, was modestly reduced in p27SJ-expressing cells. Accordingly, results from in vitro kinase assays revealed a noticeable decrease in the activity of cyclin A in cells expressing p27SJ. Cell cycle analysis demonstrated dysregulation at S and G2/M phases in cells expressing p27SJ, supporting the notion that a decline in cyclin A activity by p27SJ has a biological impact on cell growth. These observations provide evidence that p27SJ alters the state of Erk1/2 phosphorylation, and impacts several biological events associated with cell growth and function.
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Affiliation(s)
- Nune Darbinian
- Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Philadelphia, Pennsylvania 19122, USA
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18
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Lesner A, Shilpi R, Ivanova A, Gawinowicz MA, Lesniak J, Nikolov D, Simm M. Identification of X-DING-CD4, a new member of human DING protein family that is secreted by HIV-1 resistant CD4(+) T cells and has anti-viral activity. Biochem Biophys Res Commun 2009; 389:284-9. [PMID: 19720052 DOI: 10.1016/j.bbrc.2009.08.140] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Accepted: 08/25/2009] [Indexed: 10/20/2022]
Abstract
We reported previously the anti-viral activity named HRF (HIV-1 Resistance Factor) secreted by HIV-1 resistant cells. This work describes the identification of HRF from cell culture supernatant of HRF-producing cells (HRF(+) cells). Employing the proteomics and cell based activity assay we recovered ten peptides sharing 80-93% sequence homology with other eukaryotic DING proteins; discrete amino acid characteristics found in our material suggested that HRF is a new member of DING proteins family and consequently we designated it as X-DING-CD4 (extracellular DING from CD4(+) T cells). The presence of X-DING-CD4 in the extracellular compartment of HRF(+) but not control HRF(-) cells was confirmed by specific anti-X-DING-CD4 antibody. Similar as the un-fractionated HRF(+) cell culture supernatant, the purified X-DING-CD4 blocked transcription of HIV-1 LTR-promoted expression of luciferase gene and replication of HIV-1 in MAGI cells. The X-DING-CD4 -mediated anti-viral activity in MAGI cells could be blocked by specific antibody.
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Affiliation(s)
- Adam Lesner
- Protein Chemistry Laboratory, St. Luke's/Roosevelt Institute for Health Sciences, Columbia University, New York, NY 10019, USA
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19
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Berna A, Bernier F, Chabrière E, Elias M, Scott K, Suh A. For whom the bell tolls? DING proteins in health and disease. Cell Mol Life Sci 2009; 66:2205-18. [PMID: 19290474 PMCID: PMC11115607 DOI: 10.1007/s00018-009-0006-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Revised: 02/09/2009] [Accepted: 02/13/2009] [Indexed: 11/29/2022]
Abstract
DING proteins, identified mainly by their eponymous N-terminal sequences, are ubiquitous in living organisms. Amongst bacteria, they are common in pseudomonads, and have been characterised with respect to genetics and structure. They form part of a wider family of phosphate-binding proteins, with emerging roles in phosphate acquisition and pathogenicity. Many DING proteins have been isolated in eukaryotes, in which they have been associated with very diverse biological activities, often in the context of possible signalling roles. Disease states in which DING proteins have been implicated include rheumatoid arthritis, lithiasis, atherosclerosis, some tumours and tumour-associated cachexia, and bacterial and viral adherence. Complete genetic and structural characterisation of eukaryotic DING genes and proteins is still lacking, though the phosphate-binding site seems to be conserved. Whether as bacterial proteins related to bacterial pathogenicity, or as eukaryotic components of biochemical signalling systems, DING proteins require further study.
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Affiliation(s)
- Anne Berna
- Institut de Biologie Moléculaire des Plantes du CNRS, Institut de Botanique, Université de Strasbourg, 28 rue Goethe, Strasbourg Cedex, France.
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20
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Berna A, Scott K, Chabrière E, Bernier F. The DING family of proteins: ubiquitous in eukaryotes, but where are the genes? Bioessays 2009; 31:570-80. [PMID: 19360767 DOI: 10.1002/bies.200800174] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PstS and DING proteins are members of a superfamily of secreted, high-affinity phosphate-binding proteins. Whereas microbial PstS have a well-defined role in phosphate ABC transporters, the physiological function of DING proteins, named after their DINGGG N termini, still needs to be determined. PstS and DING proteins co-exist in some Pseudomonas strains, to which they confer a highly adhesive and virulent phenotype. More than 30 DING proteins have now been purified, mostly from eukaryotes. They are often associated with infections or with dysregulation of cell proliferation. Consequently, eukaryotic DING proteins could also be involved in cell-cell communication or adherence. The ubiquitous presence in eukaryotes of proteins structurally and functionally related to bacterial virulence factors is intriguing, as is the absence of eukaryotic genes encoding DING proteins in databases. DING proteins in eukaryotes could originate from unidentified commensal or symbiotic bacteria and could contribute to essential functions. Alternatively, DING proteins could be encoded by eukaryotic genes sharing special features that prevent their cloning. Both hypotheses are discussed.
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Affiliation(s)
- Anne Berna
- Institut de Biologie Moléculaire des Plantes du CNRS, Université Louis Pasteur, Institut de Botanique, Strasbourg Cedex, France
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21
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Hatton W, Silvestre V, Robins RJ, Mathé-Allainmat M, Lebreton J. Synthesis of four racemic nicotine isotopomers doubly labelled with stable isotope. J Labelled Comp Radiopharm 2009. [DOI: 10.1002/jlcr.1578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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22
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Creation of a bi-directional protein transduction system for suppression of HIV-1 expression by p27SJ. Antiviral Res 2007; 79:136-41. [PMID: 18378326 DOI: 10.1016/j.antiviral.2007.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Revised: 11/16/2007] [Accepted: 11/19/2007] [Indexed: 11/24/2022]
Abstract
p27SJ is a novel protein from a callus culture of St. John's wort that modulates transcription of the HIV-1 promoter in several mammalian cells [Darbinian-Sarkissian, N., Darbinyan, A., Otte, J., Radhakrishnan, S., Sawaya, B.E., Arzumanyan, A., Chipitsyna, G., Popov, Y., Rappaport, J., Amini, S., Khalili, K., 2006. p27(SJ), a novel protein from St. John's wort, that suppresses expression of HIV-1 genome. Gene Ther. 13, 288-295]. Here, we armed p27SJ with signals from Ig-kappa light chain that allow its efficient excretion from the cells, and from HIV-1 Tat that facilitates its uptake by other cells for its utilization by a protein transduction method. We demonstrate that treatment of cells containing the HIV-1 LTR with conditioned media from cells expressing the armed p27SJ ((exc)p27SJ(upt)) results in suppression of the viral activation by the C/EBPbeta transcription factor. Once imported into the cells, (exc)p27SJ(upt) impacts the nuclear localization of C/EBPbeta and by retaining the protein in the cytoplasm affects its DNA binding and hence transcriptional activity. The armed p27SJ also inhibits Tat-induced activation of the LTR and decreases the level of viral replication in promonocytic cells including U-937 and T-lymphocytic cells. Our observations introduce a new bi-directional protein transduction system with a broad spectrum of applications for manufacturing therapeutic peptides by a specific group of cells called donor, and delivery to the target cells named recipient. Furthermore, our results support the utility of soluble p27SJ in suppressing transcription and replication of HIV-1 by interfering with the function of cellular proteins such as C/EBPbeta and viral activators including Tat.
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23
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Diemer H, Elias M, Renault F, Rochu D, Contreras-Martel C, Schaeffer C, Van Dorsselaer A, Chabriere E. Tandem use of X-ray crystallography and mass spectrometry to obtain ab initio the complete and exact amino acids sequence of HPBP, a human 38-kDa apolipoprotein. Proteins 2007; 71:1708-20. [DOI: 10.1002/prot.21866] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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24
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Moniot S, Elias M, Kim D, Scott K, Chabriere E. Crystallization, diffraction data collection and preliminary crystallographic analysis of DING protein from Pseudomonas fluorescens. Acta Crystallogr Sect F Struct Biol Cryst Commun 2007; 63:590-2. [PMID: 17620718 PMCID: PMC2335140 DOI: 10.1107/s1744309107028102] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Accepted: 06/07/2007] [Indexed: 11/11/2022]
Abstract
PfluDING is a phosphate-binding protein expressed in Pseudomonas fluorescens. This protein is clearly distinct from the bacterial ABC transporter soluble phosphate-binding protein PstS and is more homologous to eukaryotic DING proteins. Interestingly, bacterial DING proteins have only been detected in certain Pseudomonas species. Although DING proteins seem to be ubiquitous in eukaryotes, they are systematically absent from eukaryotic genomic databases and thus are still quite mysterious and poorly characterized. PfluDING displays mitogenic activity towards human cells and binds various ligands such as inorganic phosphate, pyrophosphate, nucleotide triphosphates and cotinine. Here, the crystallization of PfluDING is reported in a monoclinic space group (P2(1)), with typical unit-cell parameters a = 36.7, b = 123.7, c = 40.8 A, alpha = 90, beta = 116.7, gamma = 90 degrees. Preliminary crystallographic analysis reveals good diffraction quality for these crystals and a 1.43 A resolution data set has been collected.
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Affiliation(s)
- Sebastien Moniot
- Laboratoire de Cristallographie et Modélisation des Matériaux Minéraux et Biologiques, CNRS–Université Henri Poincaré, 54506 Vandoeuvre-lès-Nancy, France
| | - Mikael Elias
- Laboratoire de Cristallographie et Modélisation des Matériaux Minéraux et Biologiques, CNRS–Université Henri Poincaré, 54506 Vandoeuvre-lès-Nancy, France
| | - Donghyo Kim
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Ken Scott
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Eric Chabriere
- Laboratoire de Cristallographie et Modélisation des Matériaux Minéraux et Biologiques, CNRS–Université Henri Poincaré, 54506 Vandoeuvre-lès-Nancy, France
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25
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Morales R, Berna A, Carpentier P, Contreras-Martel C, Renault F, Nicodeme M, Chesne-Seck ML, Bernier F, Dupuy J, Schaeffer C, Diemer H, Van-Dorsselaer A, Fontecilla-Camps JC, Masson P, Rochu D, Chabrière E. Découverte et structure cristallographique d’une apolipoprotéine humaine. ANNALES PHARMACEUTIQUES FRANÇAISES 2007; 65:98-107. [PMID: 17404543 DOI: 10.1016/s0003-4509(07)90023-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We report the serendipitous discovery of a human plasma phosphate binding protein (HPBP). This 38 kDa protein is co-purified with paraoxonase (PON1). The association between HPON1 and HPBP is modulated by phosphate and calcium concentrations. The HPBP X-ray structure solved at 1.9 A resolution is similar to the prokaryotic phosphate solute-binding proteins (SBPs) associated with ATP binding cassette transmembrane transporters, though phosphate-SBPs have never been characterized or predicted from nucleic acid databases in eukaryotes. However, HPBP belongs to the family of ubiquitous eukaryotic proteins named DING, meaning that phosphate-SBPs are also widespread in eukaryotes. The absence of complete genes for eukaryotic phosphate-SBP from databases is intriguing, but the astonishing 90% sequence conservation of genes between evolutionary distant species suggests that the corresponding proteins play an important function. HPBP is the first identified transporter capable of binding phosphate ions in human plasma. Thus it is thought to become a new predictor and a potential therapeutic agent for phosphate-related diseases such as atherosclerosis.
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Affiliation(s)
- R Morales
- Laboratoire de cristallogenèse et cristallographie des Protéines, Institut de Biologie Structurale J.-P. Ebel, F 38027 Grenoble
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26
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Berna A, Bernier F, Chabrière E, Perera T, Scott K. DING proteins; novel members of a prokaryotic phosphate-binding protein superfamily which extends into the eukaryotic kingdom. Int J Biochem Cell Biol 2007; 40:170-5. [PMID: 17368078 DOI: 10.1016/j.biocel.2007.02.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2006] [Revised: 02/04/2007] [Accepted: 02/05/2007] [Indexed: 10/23/2022]
Abstract
PstS proteins are the cell-bound phosphate-binding elements of the ubiquitous bacterial ABC phosphate uptake mechanisms. Primary and tertiary structures, characteristic of pstS proteins, are conserved in proteins, which are expressed in secretory operons and induced by phosphate deprivation, in Pseudomonas species. There are two subsets of these proteins; AP proteins, which are alkaline phosphatases, and DING proteins, named for their N-terminal sequence, which are phosphate-binding proteins. Both form elements of a proposed phosphate-scavenging system in pseudomonads. DING proteins have also been isolated from many eukaryotic sources, and are associated with both normal and pathological functions in mammals. Their phosphate-binding function suggests a role in biomineralization, but the ability to bind other ligands may be related to signal transduction in eukaryotes. Though it has been claimed that all such proteins may originate from pseudomonads, many eukaryotic DING proteins have unique features which are incompatible with a bacterial origin.
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Affiliation(s)
- Anne Berna
- Institut de Biologie Moléculaire des Plantes du C.N.R.S., Université Louis Pasteur, Institut de Botanique, 28 rue Goethe, 67083 Strasbourg Cedex, France.
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27
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Morales R, Berna A, Carpentier P, Contreras-Martel C, Renault F, Nicodeme M, Chesne-Seck ML, Bernier F, Dupuy J, Schaeffer C, Diemer H, Van-Dorsselaer A, Fontecilla-Camps JC, Masson P, Rochu D, Chabriere E. Serendipitous discovery and X-ray structure of a human phosphate binding apolipoprotein. Structure 2006; 14:601-9. [PMID: 16531243 DOI: 10.1016/j.str.2005.12.012] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Revised: 11/09/2005] [Accepted: 12/20/2005] [Indexed: 11/23/2022]
Abstract
We report the serendipitous discovery of a human plasma phosphate binding protein (HPBP). This 38 kDa protein is copurified with the enzyme paraoxonase. Its X-ray structure is similar to the prokaryotic phosphate solute binding proteins (SBPs) associated with ATP binding cassette transmembrane transporters, though phosphate-SBPs have never been characterized or predicted from nucleic acid databases in eukaryotes. However, HPBP belongs to the family of ubiquitous eukaryotic proteins named DING, meaning that phosphate-SBPs are also widespread in eukaryotes. The systematic absence of complete genes for eukaryotic phosphate-SBP from databases is intriguing, but the astonishing 90% sequence conservation between genes belonging to evolutionary distant species suggests that the corresponding proteins play an important function. HPBP is the only known transporter capable of binding phosphate ions in human plasma and may become a new predictor of or a potential therapeutic agent for phosphate-related diseases such as atherosclerosis.
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Affiliation(s)
- Renaud Morales
- Laboratoire de Cristallogenèse et Cristallographie des Protéines, Institut de Biologie Structurale JP EBEL, 38027 Grenoble, France
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28
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Lewis AP, Crowther D. DING proteins are from Pseudomonas. FEMS Microbiol Lett 2005; 252:215-22. [PMID: 16185819 DOI: 10.1016/j.femsle.2005.08.047] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Revised: 08/30/2005] [Accepted: 08/30/2005] [Indexed: 11/20/2022] Open
Abstract
DING proteins have been described as animal and plant proteins with potential biomineralisation, receptor or signalling roles that have been characterised by an N-terminal DINGGG-sequence. However, these sequences have only ever been identified as either N-terminal peptides or partial cDNA sequences, and have yet to be detected in any of the many genomic animal and plant genomes now available. Microbial relatives of the DING proteins have been described, which appear to be periplasmic phosphate-binding proteins. Recently, full-length Pseudomonas aeruginosa UCBPP-PA14 and Hypericum perforatum genes have been sequenced that show high homology to the published DING protein N-terminal sequences, and small peptides previously identified in conjunction with the peptide sequencing of DING proteins can also be mapped to regions across these full-length sequences. Searching with these sequences identifies other plant and animal cDNA fragments in the public nucleotide databases, and, additionally, an unordered rat genomic contig that contains a DING-like sequence on a small fragment. Analysing the codon usage of these DNA sequences identifies all of these sequences as of Pseudomonas origin, suggesting that DING proteins do not exist in eukaryotes, but instead are potentially due to microbial contamination or infection.
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Affiliation(s)
- Alan P Lewis
- Bioinformatics Discovery and Analysis, GlaxoSmithKline Medicines Research Centre, Stevenage, UK.
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Scott K, Wu L. Functional properties of a recombinant bacterial DING protein: comparison with a homologous human protein. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1744:234-44. [PMID: 15950753 DOI: 10.1016/j.bbamcr.2005.02.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2004] [Revised: 01/28/2005] [Accepted: 02/15/2005] [Indexed: 11/20/2022]
Abstract
DING proteins are highly-conserved proteins with poorly-defined cell-signalling roles in mammals. Conserved homologues are also commonplace in plants, though not as yet functionally characterized. Poor availability of the proteins, and a lack of genetic structure, hamper progress in elucidating the roles of these eukaryotic DING proteins, but highly-homologous hypothetical DING proteins have recently been identified in Pseudomonas genomes. We have cloned and expressed a DING protein from P. fluorescens SWB25 in Escherichia coli. The recombinant protein, and its natural human homologue, act as phosphate-binding proteins, as predicted by structural homologies with other bacterial proteins. The recombinant protein also displays other functional similarities with mammalian DING proteins, in that, like the human version, it acts as a mitogen for cultured human cells, and can bind cotinine, known to be a binding ligand for a rat neuronal DING protein.
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Affiliation(s)
- Ken Scott
- School of Biological Sciences, University of Auckland, New Zealand.
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Abstract
The weak estrogen-like properties of isoflavonoids were discovered over 50 y ago. In recent years, the overall effects of the isoflavones in soy on human health have been the subject of lively debate largely based on their presumed estrogenic properties. Missing from our knowledge base is the systematic identification of the cellular and biochemical targets of isoflavones and the mechanisms that they influence. Because of the benign effects of isoflavones on cellular integrity, a concentration of the isoflavones can be reached in cell culture models where almost any process can be modulated. Modern systems biology approaches and high dimensional analysis techniques offer new ways to better understand the function of how cells and integrated biological mechanisms respond to compounds such as isoflavones. Data from experiments using DNA microarray analysis for examining the effects of genistein in the developing rat uterus indicate that genistein alters the expression of 6-8 times as many genes as does a physiological estrogen such as 17 beta-estradiol. Although these new approaches are exciting, their incipient high dimensionality places considerable strain on the quality of experimental design and meaningful statistical interpretation of the resulting data. In another approach using affinity chromatography methods, DING, a novel genistein-binding protein of yet unknown function, was isolated from human breast cancer MCF-7 cells. Its function remains to be established.
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Affiliation(s)
- Stephen Barnes
- Department of Pharmacology & Toxicology, Center for Nutrient-Gene Interaction, University of Alabama at Birmingham, and Purdue University-University of Alabama at Birmingham Botanicals Center for Age-Related Disease, 35294, USA.
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Kumar V, Yu S, Farell G, Toback FG, Lieske JC. Renal epithelial cells constitutively produce a protein that blocks adhesion of crystals to their surface. Am J Physiol Renal Physiol 2004; 287:F373-83. [PMID: 15100100 DOI: 10.1152/ajprenal.00418.2003] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Attachment of newly formed crystals to renal tubular epithelial cells appears to be a critical step in the development of kidney stones. The present study was undertaken to identify autocrine factors released from renal epithelial cells into the culture medium that inhibit adhesion of calcium oxalate crystals to the cell surface. A 39-kDa glycoprotein that is constitutively secreted by renal cells was purified by gel filtration chromatography. Amino acid microsequencing revealed that it is novel and not structurally related to known inhibitors of calcium oxalate crystallization. Hence, it was named crystal adhesion inhibitor, or CAI. Immunoreactive CAI was detected in diverse rat tissues, including kidney, heart, pancreas, liver, and testis. Immunohistochemistry revealed that CAI is present in the renal cell cytosol and is also on the plasma membrane. Importantly, CAI is present in normal human urine, from which it can be purified using calcium oxalate monohydrate crystal affinity chromatography. CAI could be an important defense against crystal attachment to tubular cells and the subsequent development of renal stones in vivo.
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Affiliation(s)
- Vivek Kumar
- Division of Nephrology, Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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Belenky M, Prasain J, Kim H, Barnes S. DING, a genistein target in human breast cancer: a protein without a gene. J Nutr 2003; 133:2497S-2501S. [PMID: 12840230 DOI: 10.1093/jn/133.7.2497s] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Because most noncancer cells are tolerant to high micromolar concentrations of genistein (GEN), inhibitory or stimulatory effects of GEN have been claimed for a wide variety of biochemical targets that lead to a plethora of potential mechanisms. However, because GEN is present in tissues in the nanomol-per-liter range, most of these mechanisms are unlikely to be relevant in vivo. To better identify proteins that are targets of GEN, we used a GEN-agarose-affinity phase. Cytosols from human breast cancer MCF-7 cells were fractionated over a Sephadex diethylaminoethyl column, and nonabsorbed proteins in the flow-through were affinity absorbed onto a 2-carboxygenistein-agarose column. After proteins were washed with 100 mmol NaCl/L to remove weakly bound proteins, affinity elution was conducted with 1 mmol 2-carboxygenistein/L. Using this method, a p38 protein was recovered from MCF-7 cells. N-terminal chemical sequencing of the first 30 residues of the protein revealed a peptide sequence similar to those that have been discovered in human tissues (a T-cell attractant protein from synovial fluid from patients with osteoarthritis and an analogous human skin fibroblast protein using a hirudin-affinity column) as well as a cotonine-binding protein from rat brain and related proteins in plants. In each case, the corresponding gene has not been found. In conclusion, although much of the human genome has been sequenced, novel proteins that are not described by genome data remain to be found. The DING protein (N-terminal amino acid sequence Asp-Ile-Asn-Gly) that binds to genistein with high affinity is one of these. Its biological role, however, remains to be defined.
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Affiliation(s)
- Michael Belenky
- Department of Biochemistry and Molecular Genetics and Pharmacology and Toxicology, University of Alabama at Birmingham, AL 35294, USA
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Buccafusco JJ, Terry AV. The potential role of cotinine in the cognitive and neuroprotective actions of nicotine. Life Sci 2003; 72:2931-42. [PMID: 12706481 DOI: 10.1016/s0024-3205(03)00226-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Cotinine is a primary metabolite of nicotine that has been suggested in many studies in animals and in humans to exert measurable effects on aspects of on-going behavior or on cognitive function. Much of the interest in cotinine derives from its long pharmacological half-life (15-19 hours) relative to nicotine (2-3 hours). Despite decades of study focusing on nicotine as the predominant behaviorally active component of tobacco, there continue to be aspects of the pharmacology of the drug that have yet to be explained. For example, nicotine can evoke a protracted behavioral response, i.e., in great excess of the presence of the drug in the plasma. Also, there is often a striking differential between the potency for nicotine-induced behavioral responses in humans and animals, and its potency as a cholinergic agonist, neurochemically. One possibility that may explain one or more of these properties of nicotine is the presence of a long-lived bioactive metabolite or breakdown product of nicotine such as cotinine. Preliminary data in support of this hypothesis are consistent with the ability of cotinine to improve performance accuracy on delayed matching task by macaque monkeys, and in reversing apomorphine-induced deficits in prepulse inhibition of acoustic startle in rats. The drug also was shown to be as potent as nicotine in the ability to act as a cytoprotective agent in cells that express a neuronal cholinergic phenotype. This new appreciation for the role of cotinine in nicotine's actions, and as a pharmacological agent in its own right, particularly in aspects of cognitive function and for neuroprotection, ultimately may be applied towards the treatment of Alzheimer's disease and related disorders, and for various psychiatric syndromes.
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Affiliation(s)
- Jerry J Buccafusco
- Alzheimer's Research Center, Medical College of Georgia, Augusta, GA 30912, USA.
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Hatsukami DK, Jensen J, Brauer LH, Mooney M, Schulte S, Sofuoglu M, Pentel PR. Lack of effect of 5HT3 antagonist in mediating subjective and behavioral responses to cotinine. Pharmacol Biochem Behav 2003; 75:1-7. [PMID: 12759107 DOI: 10.1016/s0091-3057(03)00035-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previous studies have shown that cotinine, a metabolite of nicotine, may antagonize some of the therapeutic effects of nicotine. The mechanisms underlying cotinine's effects are unclear, but cotinine has been observed to increase serotonin levels in the brain. Thus, it is possible that blocking serotonin effects may antagonize the actions of cotinine, thereby reducing its impact on responses to nicotine. This study determined whether granisetron, a 5HT(3) receptor antagonist, would enhance the efficacy of the nicotine patch. Subjects were randomly assigned to one of the three granisetron conditions (N=43 for 2 mg/day; N=43 for 1 mg/day; N=42 for 0 mg/day) and asked to take the assigned medication daily during 15 days of tobacco abstinence. Because we were interested in interactions between cotinine and serotonin, all groups were also treated with a 21-mg nicotine patch. Assessments of withdrawal symptoms were made for 1 week during baseline smoking and several times during the experimental period. There was a near but nonsignificant difference among groups on a measure of tobacco withdrawal and no significant differences on global measures of drug effects or physiological measures. The data do not strongly support the hypothesis that 5HT(3) agonism is the mechanism by which cotinine offsets the effects of nicotine.
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Affiliation(s)
- Dorothy K Hatsukami
- Tobacco Use Research Center, University of Minnesota, 2701 University Avenue, #201, Minneapolis, MN 55414, USA.
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Abbruscato TJ, Lopez SP, Mark KS, Hawkins BT, Davis TP. Nicotine and cotinine modulate cerebral microvascular permeability and protein expression of ZO-1 through nicotinic acetylcholine receptors expressed on brain endothelial cells. J Pharm Sci 2002; 91:2525-38. [PMID: 12434396 DOI: 10.1002/jps.10256] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The blood-brain barrier (BBB) adapts to a variety of pathological processes. Little is known about the effects of nicotine exposure on BBB function and the ability to adapt to stroke conditions. We have demonstrated, using a well-characterized in vitro BBB model, bovine brain microvessel endothelial cells (BBMEC) model, that nicotine and its major metabolite, cotinine, modulate BBB integrity by opening the paracellular route of solute entry into the brain. Additionally, nicotine and cotinine together increase the permeability change observed after 6 h of hypoxia/aglycemia, an in vitro model of stroke. This has important implications for how the BBB initially adapts to stroke in an environment that is previously exposed to nicotine. Nicotine and cotinine exposure also resulted in reduced ZO-1 immunoreactivity (tight junctional protein) that occurred in a time-dependent manner. Interestingly, attenuation of bovine brain microvessel endothelial cell (BBMEC) ZO-1 protein expression was reversed using 10 nM BGT, an alpha7 nicotinic acetycholine receptor (nAChR) antagonist, suggesting that the effects of nicotine on BBMEC protein expression of ZO-1 protein are mediated by nAChR expressed on brain endothelial cells. In addition to alpha7, we found that BBMEC also contain positive immunoreactivity for the alpha3, alpha5, beta2, beta3 nAChR subunit. Both alpha7 and beta2 nAChR subunit protein levels decreased with prior nicotine and cotinine exposure. These data provide evidence that nicotine and cotinine alter BBB permeability and tight junctional protein expression of ZO-1, thereby altering the BBB response to stroke conditions. These changes in brain endothelial cell paracellular permeability are believed to be associated with nicotine binding to nAChRs present at the BBB.
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Affiliation(s)
- Thomas J Abbruscato
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, School of Pharmacy, 1300 Coulter, Amarillo, Texas 79106, USA.
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Abstract
DING proteins have a characteristic DINGGG- or closely related N-terminal sequence. One is found in human synovial fluid, and may be associated with rheumatoid arthritis. Other examples have receptor or signalling roles in various human and animal cells, or are involved in biomineralisation, and several of them bind to phytochemicals. As plant DING proteins have recently been discovered, we hypothesise that the DING protein-phytochemical association may represent one aspect of a ubiquitous receptor-linked signalling system. Several microbial proteins related to DING proteins have phosphatase activity, which may relate to biomineralisation in eukaryotic systems. Plant DING proteins and their microbial relatives may elicit allergic responses leading to arthritic disease.
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Affiliation(s)
- Anne Berna
- IBMP-Institut de Botanique, Strasbourg, France
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