1
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Doyle MR, Sulima A, Rice KC, Collins GT. Influence of Contingent and Noncontingent Drug Histories on the Development of High Levels of MDPV Self-Administration. J Pharmacol Exp Ther 2021; 379:108-116. [PMID: 34413199 DOI: 10.1124/jpet.121.000655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 08/16/2021] [Indexed: 11/22/2022] Open
Abstract
A subset of rats that self-administer 3,4-methylenedioxypyrovalerone (MDPV) develop unusually high levels of drug taking. A history of responding maintained by cocaine, but not food, prevents the development of this high-responder phenotype; however, it is unclear how histories of noncontingent cocaine exposure or self-administering drugs from other pharmacological classes would affect its development. In the current studies, 5 groups of male Sprague-Dawley rats were used to determine whether histories of responding maintained by drugs from different pharmacological classes (e.g., MDPV, cocaine, fentanyl, nicotine, or ketamine) would differentially impact the development of the high-responder phenotype when MDPV was available for self-administration. Two additional groups were used to determine whether noncontingent exposure to cocaine would prevent the development of the high-responder phenotype when MDPV was available for self-administration, and whether noncontingent exposure to MDPV would facilitate the development of the high-responder phenotype when cocaine was available for self-administration. Consistent with previous reports, a history of response-contingent cocaine, and to a lesser extent noncontingent cocaine, prevented the MDPV high-responder phenotype; however, when responding was initially maintained by fentanyl, nicotine, or ketamine, the MDPV high-responder phenotype developed in ∼45% of rats. By manipulating behavioral and pharmacological histories prior to evaluating MDPV self-administration, the current studies provide additional evidence that a history of response-contingent (or noncontingent) cocaine can prevent the transition from well regulated to aberrant drug-taking when responding is maintained by MDPV. Although the mechanism(s) that underlies this novel high-responder phenotype are unknown, elucidation may provide insight into individual differences relating to substance use disorder. SIGNIFICANCE STATEMENT: A subset of outbred Sprague-Dawley rats self-administer high levels of the synthetic cathinone 3,4-methylenedioxypyrovalerone (MDPV). Understanding the behavioral and/or pharmacological factors that can prevent the development of dysregulated MDPV self-administration may provide insight into individual differences in vulnerability to develop a substance use disorder.
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Affiliation(s)
- Michelle R Doyle
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas (M.R.D., G.T.C.); South Texas Veterans Health Care System, San Antonio, Texas (M.R.D., G.T.C.); and Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, NIDA and NIAAA, Bethesda, Maryland (A.S., K.C.R.)
| | - Agnieszka Sulima
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas (M.R.D., G.T.C.); South Texas Veterans Health Care System, San Antonio, Texas (M.R.D., G.T.C.); and Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, NIDA and NIAAA, Bethesda, Maryland (A.S., K.C.R.)
| | - Kenner C Rice
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas (M.R.D., G.T.C.); South Texas Veterans Health Care System, San Antonio, Texas (M.R.D., G.T.C.); and Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, NIDA and NIAAA, Bethesda, Maryland (A.S., K.C.R.)
| | - Gregory T Collins
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas (M.R.D., G.T.C.); South Texas Veterans Health Care System, San Antonio, Texas (M.R.D., G.T.C.); and Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, NIDA and NIAAA, Bethesda, Maryland (A.S., K.C.R.)
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2
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Larrimore KE, Kannan L, Kendle RP, Jamal T, Barcus M, Stefanko K, Kilbourne J, Brimijoin S, Zhan CG, Neisewander J, Mor TS. A plant-derived cocaine hydrolase prevents cocaine overdose lethality and attenuates cocaine-induced drug seeking behavior. Prog Neuropsychopharmacol Biol Psychiatry 2020; 102:109961. [PMID: 32387315 PMCID: PMC7398606 DOI: 10.1016/j.pnpbp.2020.109961] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 05/01/2020] [Accepted: 05/02/2020] [Indexed: 12/21/2022]
Abstract
Cocaine use disorders include short-term and acute pathologies (e.g. overdose) and long-term and chronic disorders (e.g. intractable addiction and post-abstinence relapse). There is currently no available treatment that can effectively reduce morbidity and mortality associated with cocaine overdose or that can effectively prevent relapse in recovering addicts. One recently developed approach to treat these problems is the use of enzymes that rapidly break down the active cocaine molecule into inactive metabolites. In particular, rational design and site-directed mutagenesis transformed human serum recombinant butyrylcholinesterase (BChE) into a highly efficient cocaine hydrolase with drastically improved catalytic efficiency toward (-)-cocaine. A current drawback preventing the clinical application of this promising enzyme-based therapy is the lack of a cost-effective production strategy that is also flexible enough to rapidly scale-up in response to continuous improvements in enzyme design. Plant-based expression systems provide a unique solution as this platform is designed for fast scalability, low cost and the advantage of performing eukaryotic protein modifications such as glycosylation. A Plant-derived form of the Cocaine Super Hydrolase (A199S/F227A/S287G/A328W/Y332G) we designate PCocSH protects mice from cocaine overdose, counters the lethal effects of acute cocaine overdose, and prevents reinstatement of extinguished drug-seeking behavior in mice that underwent place conditioning with cocaine. These results demonstrate that the novel PCocSH enzyme may well serve as an effective therapeutic for cocaine use disorders in a clinical setting.
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Affiliation(s)
| | - Latha Kannan
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA; Center of Immunotherapy, Vaccines, and Virotherapy, Biodesign Institute, Arizona State University, Tempe, AZ 85287-4501, USA.
| | - R Player Kendle
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA.
| | - Tameem Jamal
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA.
| | - Matthew Barcus
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA.
| | - Kathryn Stefanko
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA
| | - Jacquelyn Kilbourne
- Center of Immunotherapy, Vaccines, and Virotherapy, Biodesign Institute, Arizona State University, Tempe, AZ 85287-4501, USA.
| | - Stephen Brimijoin
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.
| | - Chang-Guo Zhan
- Molecular Modeling and Biopharmaceutical Center and Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA.
| | - Janet Neisewander
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA.
| | - Tsafrir S Mor
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA; Center of Immunotherapy, Vaccines, and Virotherapy, Biodesign Institute, Arizona State University, Tempe, AZ 85287-4501, USA.
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3
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Huang H, Fang L, Xue L, Zhang T, Kim K, Hou S, Zheng F, Zhan CG. PEGylation but Not Fc-Fusion Improves in Vivo Residence Time of a Thermostable Mutant of Bacterial Cocaine Esterase. Bioconjug Chem 2019; 30:3021-3027. [PMID: 31661952 DOI: 10.1021/acs.bioconjchem.9b00622] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
It is very popular to fuse a protein drug or drug candidate to the Fc domain of immunoglobulin G (IgG) in order to prolong the in vivo half-life. In this study, we have designed, prepared, and tested an Fc-fused thermostable cocaine esterase (CocE) mutant (known as E196-301, with the T172R/G173Q/L196C/I301C substitutions on CocE) expressed in E. coli. As expected, Fc-fusion does not affect the in vitro enzyme activity and thermal stability of the enzyme and that Fc-E196-301 can favorably bind FcRn with Kd = 386 ± 35 nM. However, Fc-fusion does not prolong the in vivo half-life of E196-301 at all; Fc-E196-301 and E196-301 have essentially the same PK profile (t1/2 = 0.4 ± 0.1 h) in rats. This is the first time demonstrating that Fc-fusion does not prolong in vivo half-life of a protein. This finding is consistent with the mechanistic understanding that E196-301 and Fc-E196-301 are all degraded primarily through rapid proteolysis in the body. The Fc fusion cannot protect E196-301 from the proteolysis in the body. Nevertheless, it has been demonstrated that PEGylation can effectively protect E196-301, as the PEGylated E196-301, i.e., PEG-E196-301, has a significantly prolonged in vivo half-life. It has also been demonstrated that both E196-301 and PEG-E196-301 have dose-dependent in vivo half-lives (e.g., 19.9 ± 6.4 h for the elimination t1/2 of 30 mg/kg PEG-E196-301), as the endogenous proteolytic enzymes responsible for proteolysis of E196-301 (PEGylated or not) are nearly saturated by the high plasma concentration produced by a high dose of E196-301 or PEG-E196-301.
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Affiliation(s)
- Haifeng Huang
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy , University of Kentucky , Lexington , Kentucky 40536 , United States.,Department of Pharmaceutical Sciences, College of Pharmacy , University of Kentucky , Lexington , Kentucky 40536 , United States
| | - Lei Fang
- Department of Pharmaceutical Sciences, College of Pharmacy , University of Kentucky , Lexington , Kentucky 40536 , United States
| | - Liu Xue
- Department of Pharmaceutical Sciences, College of Pharmacy , University of Kentucky , Lexington , Kentucky 40536 , United States
| | - Ting Zhang
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy , University of Kentucky , Lexington , Kentucky 40536 , United States.,Department of Pharmaceutical Sciences, College of Pharmacy , University of Kentucky , Lexington , Kentucky 40536 , United States
| | - Kyungbo Kim
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy , University of Kentucky , Lexington , Kentucky 40536 , United States.,Department of Pharmaceutical Sciences, College of Pharmacy , University of Kentucky , Lexington , Kentucky 40536 , United States
| | - Shurong Hou
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy , University of Kentucky , Lexington , Kentucky 40536 , United States.,Department of Pharmaceutical Sciences, College of Pharmacy , University of Kentucky , Lexington , Kentucky 40536 , United States
| | - Fang Zheng
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy , University of Kentucky , Lexington , Kentucky 40536 , United States.,Department of Pharmaceutical Sciences, College of Pharmacy , University of Kentucky , Lexington , Kentucky 40536 , United States
| | - Chang-Guo Zhan
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy , University of Kentucky , Lexington , Kentucky 40536 , United States.,Department of Pharmaceutical Sciences, College of Pharmacy , University of Kentucky , Lexington , Kentucky 40536 , United States
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4
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Zheng X, Zhou Z, Zhang T, Jin Z, Chen X, Deng J, Zhan CG, Zheng F. Effectiveness of a Cocaine Hydrolase for Cocaine Toxicity Treatment in Male and Female Rats. AAPS JOURNAL 2017; 20:3. [PMID: 29181644 DOI: 10.1208/s12248-017-0167-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 11/02/2017] [Indexed: 11/30/2022]
Abstract
Development of a truly effective medication for treatment of cocaine abuse has been a grand challenge. There is no FDA-approved therapeutic agent specific for cocaine addiction or overdose. An enzyme therapy using an efficient cocaine-metabolizing enzyme could be a promising treatment strategy for cocaine overdose and addiction. One of our previously designed cocaine hydrolases (CocHs), known as CocH1, was fused with human serum albumin (HSA) to prolong the biological half-life. The fusion protein CocH1-HSA is an investigational new drug (IND) approved by the FDA for clinical trials in cocaine addiction treatment, but not in cocaine overdose/toxicity treatment. In the present study, we aimed to evaluate the pharmacokinetic profile of CocH1-HSA and its effectiveness for cocaine toxicity treatment in male and female rats and demonstrate the clinical potential. The data demonstrate that enzyme CocH1-HSA has very similar pharmacokinetic profile in male and female rats. For both male and female rats, the enzyme can rapidly eliminate cocaine even if the cocaine dose is as high as 180 mg/kg (LD100). Based on the animal data, whenever the enzyme is given to a living subject, the remaining cocaine in the body will be converted rapidly to physiologically inactive metabolites and, thus, reverse the cocaine toxicity and help the subject to recover. So, an enzyme therapy using CocH1-HSA can effectively treat cocaine toxicity and prevent the subject from further damage by cocaine. The data obtained clearly demonstrate the promising clinical potential of CocH1-HSA in cocaine overdose treatment for both genders.
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Affiliation(s)
- Xirong Zheng
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA
| | - Ziyuan Zhou
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA
| | - Ting Zhang
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA
| | - Zhenyu Jin
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA
| | - Xiabin Chen
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA
| | - Jing Deng
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA
| | - Chang-Guo Zhan
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA. .,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA.
| | - Fang Zheng
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA. .,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky, 40536, USA.
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5
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Zhang T, Zheng X, Zhou Z, Chen X, Jin Z, Deng J, Zhan CG, Zheng F. Clinical Potential of an Enzyme-based Novel Therapy for Cocaine Overdose. Sci Rep 2017; 7:15303. [PMID: 29127295 PMCID: PMC5681513 DOI: 10.1038/s41598-017-14105-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 10/02/2017] [Indexed: 12/19/2022] Open
Abstract
It is a grand challenge to develop a truly effective medication for treatment of cocaine overdose. The current available, practical emergence treatment for cocaine overdose includes administration of a benzodiazepine anticonvulsant agent (e.g. diazepam) and/or physical cooling with an aim to relieve the symptoms. The inherent difficulties of antagonizing physiological effects of drugs in the central nervous system have led to exploring protein-based pharmacokinetic approaches using biologics like vaccines, monoclonal antibodies, and enzymes. However, none of the pharmacokinetic agents has demonstrated convincing preclinical evidence of clinical potential for drug overdose treatment without a question mark on the timing used in the animal models. Here we report the use of animal models, including locomotor activity, protection, and rescue experiments in rats, of drug toxicity treatment with clinically relevant timing for the first time. It has been demonstrated that an efficient cocaine-metabolizing enzyme developed in our previous studies can rapidly reverse the cocaine toxicity whenever the enzyme is given to a living rat, demonstrating promising clinical potential of an enzyme-based novel therapy for cocaine overdose as a successful example in comparison with the commonly used diazepam.
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Affiliation(s)
- Ting Zhang
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA
| | - Xirong Zheng
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA
| | - Ziyuan Zhou
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA
| | - Xiabin Chen
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA
| | - Zhenyu Jin
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA
| | - Jing Deng
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA
| | - Chang-Guo Zhan
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA. .,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA.
| | - Fang Zheng
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA. .,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536, USA.
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6
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Zhang Y, Huang X, Han K, Zheng F, Zhan CG. Free energy profiles of cocaine esterase-cocaine binding process by molecular dynamics and potential of mean force simulations. Chem Biol Interact 2016; 259:142-147. [PMID: 27163853 DOI: 10.1016/j.cbi.2016.05.011] [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: 01/09/2016] [Revised: 04/29/2016] [Accepted: 05/05/2016] [Indexed: 11/29/2022]
Abstract
The combined molecular dynamics (MD) and potential of mean force (PMF) simulations have been performed to determine the free energy profile of the CocE)-(+)-cocaine binding process in comparison with that of the corresponding CocE-(-)-cocaine binding process. According to the MD simulations, the equilibrium CocE-(+)-cocaine binding mode is similar to the CocE-(-)-cocaine binding mode. However, based on the simulated free energy profiles, a significant free energy barrier (∼5 kcal/mol) exists in the CocE-(+)-cocaine binding process whereas no obvious free energy barrier exists in the CocE-(-)-cocaine binding process, although the free energy barrier of ∼5 kcal/mol is not high enough to really slow down the CocE-(+)-cocaine binding process. In addition, the obtained free energy profiles also demonstrate that (+)-cocaine and (-)-cocaine have very close binding free energies with CocE, with a negligible difference (∼0.2 kcal/mol), which is qualitatively consistent with the nearly same experimental KM values of the CocE enzyme for (+)-cocaine and (-)-cocaine. The consistency between the computational results and available experimental data suggests that the mechanistic insights obtained from this study are reasonable.
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Affiliation(s)
- Yuxin Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Zhongshan Road 457, Dalian 116023, PR China; Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
| | - Xiaoqin Huang
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
| | - Keli Han
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Zhongshan Road 457, Dalian 116023, PR China
| | - Fang Zheng
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
| | - Chang-Guo Zhan
- Molecular Modeling and Biopharmaceutical Center, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA.
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7
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Abstract
Cocaine abuse is a world-wide public health and social problem without a US Food and Drug Administration-approved medication. An ideal anticocaine medication would accelerate cocaine metabolism, producing biologically inactive metabolites by administration of an efficient cocaine-specific exogenous enzyme. Our recent studies have led to the discovery of the desirable, highly efficient cocaine hydrolases (CocHs) that can efficiently detoxify and inactivate cocaine without affecting normal functions of the CNS. Preclinical and clinical data have demonstrated that these CocHs are safe for use in humans and are effective for accelerating cocaine metabolism. However, the actual therapeutic use of a CocH in cocaine addiction treatment is limited by its short biological half-life (e.g., 8 h or shorter in rats). Here we demonstrate a novel CocH form, a catalytic antibody analog, which is a fragment crystallizable (Fc)-fused CocH dimer (CocH-Fc) constructed by using CocH to replace the Fab region of human IgG1. The CocH-Fc not only has a high catalytic efficiency against cocaine but also, like an antibody, has a considerably longer biological half-life (e.g., ∼107 h in rats). A single dose of CocH-Fc was able to accelerate cocaine metabolism in rats even after 20 d and thus block cocaine-induced hyperactivity and toxicity for a long period. Given the general observation that the biological half-life of a protein drug is significantly longer in humans than in rodents, the CocH-Fc reported in this study could allow dosing once every 2-4 wk, or longer, for treatment of cocaine addiction in humans.
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8
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Fang L, Chow KM, Hou S, Xue L, Chen X, Rodgers D, Zheng F, Zhan CG. Rational design, preparation, and characterization of a therapeutic enzyme mutant with improved stability and function for cocaine detoxification. ACS Chem Biol 2014; 9:1764-72. [PMID: 24919140 PMCID: PMC4136690 DOI: 10.1021/cb500257s] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Cocaine esterase (CocE) is known as the most efficient natural enzyme for cocaine hydrolysis. The major obstacle to the clinical application of wild-type CocE is the thermoinstability with a half-life of only ∼12 min at 37 °C. The previously designed T172R/G173Q mutant (denoted as enzyme E172-173) with an improved in vitro half-life of ∼6 h at 37 °C is currently in clinical trial Phase II for cocaine overdose treatment. Through molecular modeling and dynamics simulation, we designed and characterized a promising new mutant of E172-173 with extra L196C/I301C mutations (denoted as enzyme E196-301) to produce cross-subunit disulfide bonds that stabilize the dimer structure. The cross-subunit disulfide bonds were confirmed by X-ray diffraction. The designed L196C/I301C mutations have not only considerably extended the in vitro half-life at 37 °C to >100 days, but also significantly improved the catalytic efficiency against cocaine by ∼150%. In addition, the thermostable E196-301 can be PEGylated to significantly prolong the residence time in mice. The PEGylated E196-301 can fully protect mice from a lethal dose of cocaine (180 mg/kg, LD100) for at least 3 days, with an average protection time of ∼94h. This is the longest in vivo protection of mice from the lethal dose of cocaine demonstrated within all studies using an exogenous enzyme reported so far. Hence, E196-301 may be developed to become a more valuable therapeutic enzyme for cocaine abuse treatment, and it demonstrates that a general design strategy and protocol to simultaneously improve both the stability and function are feasible for rational protein drug design.
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Affiliation(s)
- Lei Fang
- Molecular
Modeling and Biopharmaceutical Center and Department of Pharmaceutical
Sciences, College of Pharmacy, University
of Kentucky, 789 South
Limestone Street, Lexington, Kentucky 40536, United
States
| | - K. Martin Chow
- Department
of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, 741 South Limestone Street, Lexington, Kentucky 40536, United States
| | - Shurong Hou
- Molecular
Modeling and Biopharmaceutical Center and Department of Pharmaceutical
Sciences, College of Pharmacy, University
of Kentucky, 789 South
Limestone Street, Lexington, Kentucky 40536, United
States
| | - Liu Xue
- Molecular
Modeling and Biopharmaceutical Center and Department of Pharmaceutical
Sciences, College of Pharmacy, University
of Kentucky, 789 South
Limestone Street, Lexington, Kentucky 40536, United
States
| | - Xiabin Chen
- Molecular
Modeling and Biopharmaceutical Center and Department of Pharmaceutical
Sciences, College of Pharmacy, University
of Kentucky, 789 South
Limestone Street, Lexington, Kentucky 40536, United
States
| | - David
W. Rodgers
- Department
of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, 741 South Limestone Street, Lexington, Kentucky 40536, United States
| | - Fang Zheng
- Molecular
Modeling and Biopharmaceutical Center and Department of Pharmaceutical
Sciences, College of Pharmacy, University
of Kentucky, 789 South
Limestone Street, Lexington, Kentucky 40536, United
States
| | - Chang-Guo Zhan
- Molecular
Modeling and Biopharmaceutical Center and Department of Pharmaceutical
Sciences, College of Pharmacy, University
of Kentucky, 789 South
Limestone Street, Lexington, Kentucky 40536, United
States,Tel.: 859-323-3943.
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9
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Abstract
The pharmacokinetic approach to treatment targets the drug molecules themselves, aiming to reduce their concentration at the site of action, thereby reducing or preventing any pharmacodynamic effect. This approach might be useful in the treatment of acute drug toxicity/overdose and in the long-term treatment of addiction. Early clinical trials with anticocaine and antinicotine vaccines have shown reduced drug use and good tolerability. Also showing promise in animal studies are monoclonal antibodies against cocaine, methamphetamine and phencyclidine, as well as the enhancment of cocaine metabolism with genetic variants of human butyrylcholinesterase, using a bacterial esterase or catalytic monoclonal antibodies. Pharmacokinetic treatments offer potential advantages in terms of patient compliance, absence of medication interactions and benefit for patients who cannot take standard medications.
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Affiliation(s)
- David A Gorelick
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA.
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10
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Zhan CG. Novel pharmacological approaches to treatment of drug overdose and addiction. Expert Rev Clin Pharmacol 2014; 2:1-4. [PMID: 21072135 DOI: 10.1586/17512433.2.1.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Chang-Guo Zhan
- University of Kentucky, Department of Pharmaceutical Sciences, College of Pharmacy, 789 South Limestone Street, Lexington, KY 40536, USA TEL: 859-323-3943 FAX: 859-323-3575
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11
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Accelerating cocaine metabolism as an approach to the treatment of cocaine abuse and toxicity. Future Med Chem 2012; 4:163-75. [PMID: 22300096 DOI: 10.4155/fmc.11.181] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
One pharmacokinetic approach to the treatment of cocaine abuse and toxicity involves the development of compounds that can be safely administered to humans and that accelerate the metabolism of cocaine to inactive components. Catalytic antibodies have been developed and shown to accelerate cocaine metabolism, but their catalytic efficiency for cocaine is relatively low. Mutations of human butyrylcholinesterase and a bacterial cocaine esterase found in the soil of coca plants have also been developed. These compounds accelerate cocaine metabolism and antagonize the behavioral and toxic effects of cocaine in animal models. Of these two approaches, the human butyrylcholinesterase mutants show the most immediate promise as they would not be expected to evoke an immune response in humans.
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12
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Bacterial cocaine esterase: a protein-based therapy for cocaine overdose and addiction. Future Med Chem 2012; 4:137-50. [PMID: 22300094 DOI: 10.4155/fmc.11.194] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Cocaine is highly addictive and there are no pharmacotherapeutic drugs available to treat acute cocaine toxicity or chronic abuse. Antagonizing an inhibitor such as cocaine using a small molecule has proven difficult. The alternative approach is to modify cocaine's pharmacokinetic properties by sequestering or hydrolyzing it in serum and limiting access to its sites of action. We took advantage of a bacterial esterase (CocE) that has evolved to hydrolyze cocaine and have developed it as a therapeutic that rapidly and specifically clears cocaine from the subject. Native enzyme was unstable at 37°C, thus limiting CocE's potential. Innovative computational methods based on the protein's structure helped elucidate its mechanism of destabilization. Novel protein engineering methodologies were applied to substantially improve its stability in vitro and in vivo. These improvements rendered CocE as a powerful and efficacious therapeutic to treat cocaine intoxication and lead the way towards developing a therapy for addiction.
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13
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Collins GT, Brim RL, Noon KR, Narasimhan D, Lukacs NW, Sunahara RK, Woods JH, Ko MC. Repeated administration of a mutant cocaine esterase: effects on plasma cocaine levels, cocaine-induced cardiovascular activity, and immune responses in rhesus monkeys. J Pharmacol Exp Ther 2012; 342:205-13. [PMID: 22518021 DOI: 10.1124/jpet.112.194639] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous studies have demonstrated the capacity of a long-acting mutant form of a naturally occurring bacterial double mutant cocaine esterase (DM CocE) to antagonize the reinforcing, discriminative, convulsant, and lethal effects of cocaine in rodents and reverse the increases in mean arterial pressure (MAP) and heart rate (HR) produced by cocaine in rhesus monkeys. This study was aimed at characterizing the immunologic responses to repeated dosing with DM CocE and determining whether the development of anti-CocE antibodies altered the capacity of DM CocE to reduce plasma cocaine levels and ameliorate the cardiovascular effects of cocaine in rhesus monkeys. Under control conditions, intravenous administration of cocaine (3 mg/kg) resulted in a rapid increase in the plasma concentration of cocaine (n = 2) and long-lasting increases in MAP and HR (n = 3). Administration of DM CocE (0.32 mg/kg i.v.) 10 min after cocaine resulted in a rapid hydrolysis of cocaine with plasma levels below detection limits within 5 to 8 min. Elevations in MAP and HR were significantly reduced within 25 and 50 min of DM CocE administration, respectively. Although slight (10-fold) increases in anti-CocE antibodies were observed after the fourth administration of DM CocE, these antibodies did not alter the capacity of DM CocE to reduce plasma cocaine levels or ameliorate cocaine's cardiovascular effects. Anti-CocE titers were transient and generally dissipated within 8 weeks. Together, these results suggest that highly efficient cocaine esterases, such as DM CocE, may provide a novel and effective therapeutic for the treatment of acute cocaine intoxication in humans.
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Affiliation(s)
- Gregory T Collins
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109-0632, USA
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14
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Long-lasting effects of a PEGylated mutant cocaine esterase (CocE) on the reinforcing and discriminative stimulus effects of cocaine in rats. Neuropsychopharmacology 2012; 37:1092-103. [PMID: 21993206 PMCID: PMC3306869 DOI: 10.1038/npp.2011.226] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recent mutagenesis studies have identified a mutant G4C/S10C/T172R/G173Q cocaine esterase (CCRQ CocE) with an in vitro duration of action of >40 days. Although the in vivo duration of CCRQ CocE's action was <24 h, modification of this enzyme with polyethylene glycol (PEG) polymers resulted in a CocE (PEG-CCRQ CocE) capable of preventing cocaine-induced lethality for up to 72 h. The current studies were aimed at providing a detailed characterization of the effectiveness, selectivity, and duration of PEG-CCRQ CocE's actions in cocaine self-administration and discrimination assays in rats. Pretreatment with PEG-CCRQ CocE produced dose-dependent rightward shifts in the dose-response curves for cocaine self-administration and discrimination, with the highest dose of PEG-CCRQ CocE capable of producing an initial shift of cocaine's reinforcing and interoceptive effects of >30-fold to the right, with significant inhibition of these effects observed for up to 72 h. Although PEG-CCRQ CocE also produced slight reductions in the rates of methylphenidate- and food-reinforced responding, these effects were short-lived, lasting <24 h. Finally, when taken together with the finding that PEG-CCRQ CocE failed to alter the cocaine-like interoceptive effects of either methylphenidate or d-amphetamine, these results suggest that PEG-CCRQ CocE possesses a high degree of pharmacologic specificity for cocaine and a prolonged in vivo duration of action. In conclusion, these studies provide strong evidence to support the further development of long-lasting, highly efficient CocEs, such as PEG-CCRQ CocE, as a potential therapeutic option for the treatment of cocaine abuse in humans.
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15
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Huang X, Zhao X, Zheng F, Zhan CG. Cocaine esterase-cocaine binding process and the free energy profiles by molecular dynamics and potential of mean force simulations. J Phys Chem B 2012; 116:3361-8. [PMID: 22385120 DOI: 10.1021/jp2111605] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The combined molecular dynamics (MD) and potential of mean force (PMF) simulations have been performed to determine the free energy profiles for the binding process of (-)-cocaine interacting with wild-type cocaine esterase (CocE) and its mutants (T172R/G173Q and L119A/L169K/G173Q). According to the MD simulations, the general protein-(-)-cocaine binding mode is not affected by the mutations; e.g.. the benzoyl group of (-)-cocaine is always bound in a subsite composed of aromatic residues W151, W166, F261, and F408 and hydrophobic residue L407, while the carbonyl oxygen on the benzoyl group of (-)-cocaine is hydrogen-bonded with the oxyanion-hole residues Y44 and Y118. According to the PMF-calculated free energy profiles for the binding process, the binding free energies for (-)-cocaine with the wild-type, T172R/G173Q, and L119A/L169K/G173Q CocEs are predicted to be -6.4, -6.2, and -5.0 kcal/mol, respectively. The computational predictions are supported by experimental kinetic data, as the calculated binding free energies are in good agreement with the experimentally derived binding free energies, i.e., -7.2, -6.7, and -4.8 kcal/mol for the wild-type, T172R/G173Q, and L119A/L169K/G173Q, respectively. The reasonable agreement between the computational and experimental data suggests that the PMF simulations may be used as a valuable tool in new CocE mutant design that aims to decrease the Michaelis-Menten constant of the enzyme for (-)-cocaine.
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Affiliation(s)
- Xiaoqin Huang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, USA
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16
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Brim RL, Noon KR, Collins GT, Stein A, Nichols J, Narasimhan D, Ko MC, Woods JH, Sunahara RK. The fate of bacterial cocaine esterase (CocE): an in vivo study of CocE-mediated cocaine hydrolysis, CocE pharmacokinetics, and CocE elimination. J Pharmacol Exp Ther 2012; 340:83-95. [PMID: 21990608 PMCID: PMC3251018 DOI: 10.1124/jpet.111.186049] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 10/06/2011] [Indexed: 11/22/2022] Open
Abstract
Cocaine abuse and toxicity remain widespread problems in the United States. Currently cocaine toxicity is treated only symptomatically, because there is no Food and Drug Administration-approved pharmacotherapy for this indication. To address the unmet need, a stabilized mutant of bacterial cocaine esterase [T172R/G173Q-CocE (DM-CocE)], which hydrolyzes cocaine into inactive metabolites and has low immunogenic potential, has been developed and previously tested in animal models of cocaine toxicity. Here, we document the rapid cocaine hydrolysis by low doses of DM-CocE in vitro and in vivo, as well as the pharmacokinetics and distribution of the DM-CocE protein in rats. DM-CocE at 50.5 μg/kg effectively eliminated 4 mg/kg cocaine within 2 min in both male and female rats as measured by mass spectrometry. We expanded on these findings by using a pharmacologically relevant dose of DM-CocE (0.32 mg/kg) in rats and monkeys to hydrolyze convulsant doses of cocaine. DM-CocE reduced cocaine to below detection limits rapidly after injection; however, elimination of DM-CocE resulted in peripheral cocaine redistribution by 30 to 60 min. Elimination of DM-CocE was quantified by using [³⁵S] labeling of the enzyme and was found to have a half-life of 2.1 h in rats. Minor urinary output of DM-CocE was also observed. Immunohistochemistry, Western blotting, and radiography all were used to elucidate the mechanism of DM-CocE elimination, rapid proteolysis, and recycling of amino acids into all tissues. This rapid elimination of DM-CocE is a desirable property of a therapeutic for cocaine toxicity and should reduce the likelihood of immunogenic or adverse reactions as DM-CocE moves toward clinical use.
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Affiliation(s)
- Remy L Brim
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan, USA
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17
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Brim RL, Noon KR, Nichols J, Narasimhan D, Woods JH, Sunahara RK. Evaluation of the hydrolytic activity of a long-acting mutant bacterial cocaine in the presence of commonly co-administered drugs. Drug Alcohol Depend 2011; 119:224-8. [PMID: 21775073 PMCID: PMC3217061 DOI: 10.1016/j.drugalcdep.2011.06.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 05/03/2011] [Accepted: 06/19/2011] [Indexed: 11/19/2022]
Abstract
BACKGROUND Cocaine toxicity is a prevalent problem in the Unites States for which there is currently no FDA-approved pharmacotherapy. We have developed a bacterial cocaine esterase (CocE) towards this indication. A thermostabilized mutant of CocE (DM-CocE) retains the hydrolytic activity of the wild-type esterase, rapidly hydrolyzing cocaine into the inactive metabolites ecgonine methyl ester and benzoic acid, and can prevent cocaine toxicities in rodent and non-human primate models. To advance DM-CocE towards clinical use, we examine here how the hydrolytic activity of DM-CocE is altered by some drugs commonly co-administered with cocaine. METHODS We employed a spectrophotometric cocaine hydrolysis assay to evaluate whether pharmacologically relevant doses of alcohol, nicotine, morphine, phencyclidine, ketamine, methamphetamine, naltrexone, naloxone, or midazolam would alter the Michaelis-Menten kinetics of DM-CocE for cocaine. Mass spectrometry was used to evaluate interaction with diazepam as this drug interferes with the absorbance spectra of cocaine critical for the spectrophotometric assay. RESULTS Alcohol, nicotine, morphine, phencyclidine, ketamine, methamphetamine, naltrexone, naloxone, and midazolam did not alter cocaine hydrolysis by DM-CocE. However, diazepam significantly slowed DM-CocE cocaine hydrolysis at very high concentrations, most likely through interaction of the phenyl ring of the benzodiazepine with the active site of DM-CocE. CONCLUSIONS DM-CocE does not display significant drug interactions, with the exception of diazepam, which may warrant further study as DM-CocE progresses towards a clinically used pharmacotherapy for cocaine toxicity. Alternate benzodiazepines, e.g., midazolam could be used to avoid this potential interaction.
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Affiliation(s)
- Remy L Brim
- University of Michigan, Department of Pharmacology, USA
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18
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Collins GT, Zaks ME, Cunningham AR, St. Clair C, Nichols J, Narasimhan D, Ko MC, Sunahara RK, Woods JH. Effects of a long-acting mutant bacterial cocaine esterase on acute cocaine toxicity in rats. Drug Alcohol Depend 2011; 118:158-65. [PMID: 21481548 PMCID: PMC3150623 DOI: 10.1016/j.drugalcdep.2011.03.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 03/16/2011] [Accepted: 03/17/2011] [Indexed: 10/18/2022]
Abstract
BACKGROUND A longer acting, double mutant bacterial cocaine esterase (CocE T172R/G173Q; DM CocE) has been shown to protect mice from cocaine-induced lethality, inhibit the reinforcing effects of cocaine in rats, and reverse cocaine's cardiovascular effects in rhesus monkeys. The current studies evaluated the effectiveness of DM CocE to protect against, and reverse cocaine's cardiovascular, convulsant, and lethal effects in male and female rats. METHODS Pretreatment studies were used to determine the effectiveness and in vivo duration of action for DM CocE to protect rats against the occurrence of cardiovascular changes, convulsion and lethality associated with acute cocaine toxicity. Posttreatment studies were used to evaluate the capacity of DM CocE to rescue rats from the cardiovascular and lethal effects of large doses of cocaine. In addition, male and female rats were studied to determine if there were any potential effects of sex on the capacity of DM CocE to protect against, or reverse acute cocaine toxicity in rats. RESULTS Pretreatment with DM CocE dose-dependently protected rats against cocaine-induced cardiovascular changes, convulsion and lethality, with higher doses active for up to 4h, and shifting cocaine-induced lethality at least 10-fold to the right. In addition to dose-dependently recovering rats from an otherwise lethal dose of cocaine, post-treatment with DM CocE also reversed the cardiovascular effects of cocaine. There were no sex-related differences in the effectiveness of DM CocE to protect against, or reverse acute cocaine toxicity. CONCLUSIONS Together, these results support the development of DM CocE for the treatment of acute cocaine toxicity.
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19
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Narasimhan D, Collins GT, Nance MR, Nichols J, Edwald E, Chan J, Ko MC, Woods JH, Tesmer JJG, Sunahara RK. Subunit stabilization and polyethylene glycolation of cocaine esterase improves in vivo residence time. Mol Pharmacol 2011; 80:1056-65. [PMID: 21890748 DOI: 10.1124/mol.111.074997] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
No small-molecule therapeutic is available to treat cocaine addiction, but enzyme-based therapy to accelerate cocaine hydrolysis in serum has gained momentum. Bacterial cocaine esterase (CocE) is the fastest known native enzyme that hydrolyzes cocaine. However, its lability at 37°C has limited its therapeutic potential. Cross-linking subunits through disulfide bridging is commonly used to stabilize multimeric enzymes. Herein we use structural methods to guide the introduction of two cysteine residues within dimer interface of CocE to facilitate intermolecular disulfide bond formation. The disulfide-crosslinked enzyme displays improved thermostability, particularly when combined with previously described mutations that enhance stability (T172R-G173Q). The newly modified enzyme yielded an extremely stable form of CocE (CCRQ-CocE) that retained greater than 90% of its activity after 41 days at 37°C, representing an improvement of more than 4700-fold over the wild-type enzyme. CCRQ-CocE could also be modified by polyethylene glycol (PEG) polymers, which improved its in vivo residence time from 24 to 72 h, as measured by a cocaine lethality assay, by self-administration in rodents, and by measurement of inhibition of cocaine-induced cardiovascular effects in rhesus monkeys. PEG-CCRQ elicited negligible immune response in rodents. Subunit stabilization and PEGylation has thus produced a potential protein therapeutic with markedly higher stability both in vitro and in vivo.
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Affiliation(s)
- Diwahar Narasimhan
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
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20
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Recent progress in protein drug design and discovery with a focus on novel approaches to the development of anti-cocaine medications. Future Med Chem 2011; 1:515-28. [PMID: 20161378 DOI: 10.4155/fmc.09.20] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Cocaine is highly addictive and no anti-cocaine medication is currently available. Accelerating cocaine metabolism, producing biologically inactive metabolites, is recognized as an ideal anti-cocaine medication strategy, especially for the treatment of acute cocaine toxicity. However, currently known wild-type enzymes have either too low a catalytic efficiency against the abused cocaine, in other words (-)-cocaine, or the in vivo half-life is too short. Novel computational strategies and design approaches have been developed recently to design and discover thermostable or high-activity mutants of enzymes based on detailed structures and catalytic/inactivation mechanisms. The structure- and mechanism-based computational design efforts have led to the discovery of high-activity mutants of butyrylcholinesterase and thermostable mutants of cocaine esterase as promising anti-cocaine therapeutics. The structure- and mechanism-based computational strategies and design approaches may be used to design high-activity and/or thermostable mutants of many other proteins that have clear therapeutic potentials and to design completely new therapeutic enzymes.
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21
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Huang X, Gao D, Zhan CG. Computational design of a thermostable mutant of cocaine esterase via molecular dynamics simulations. Org Biomol Chem 2011; 9:4138-43. [PMID: 21373712 PMCID: PMC4365906 DOI: 10.1039/c0ob00972e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cocaine esterase (CocE) has been known as the most efficient native enzyme for metabolizing naturally occurring cocaine. A major obstacle to the clinical application of CocE is the thermoinstability of native CocE with a half-life of only ∼11 min at physiological temperature (37 °C). It is highly desirable to develop a thermostable mutant of CocE for therapeutic treatment of cocaine overdose and addiction. To establish a structure-thermostability relationship, we carried out molecular dynamics (MD) simulations at 400 K on wild-type CocE and previously known thermostable mutants, demonstrating that the thermostability of the active form of the enzyme correlates with the fluctuation (characterized as the root-mean square deviation and root-mean square fluctuation of atomic positions) of the catalytic residues (Y44, S117, Y118, H287, and D259) in the simulated enzyme. In light of the structure-thermostability correlation, further computational modelling including MD simulations at 400 K predicted that the active site structure of the L169K mutant should be more thermostable. The prediction has been confirmed by wet experimental tests showing that the active form of the L169K mutant had a half-life of 570 min at 37 °C, which is significantly longer than those of the wild-type and previously known thermostable mutants. The encouraging outcome suggests that the high-temperature MD simulations and the structure-thermostability relationship may be considered as a valuable tool for the computational design of thermostable mutants of an enzyme.
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Affiliation(s)
- Xiaoqin Huang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536
| | - Daquan Gao
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536
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22
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Liu J, Zhao X, Yang W, Zhan CG. Reaction mechanism for cocaine esterase-catalyzed hydrolyses of (+)- and (-)-cocaine: unexpected common rate-determining step. J Phys Chem B 2011; 115:5017-25. [PMID: 21486046 PMCID: PMC3087188 DOI: 10.1021/jp200975v] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
First-principles quantum mechanical/molecular mechanical free energy calculations have been performed to examine the catalytic mechanism for cocaine esterase (CocE)-catalyzed hydrolysis of (+)-cocaine in comparison with CocE-catalyzed hydrolysis of (-)-cocaine. It has been shown that the acylation of (+)-cocaine consists of nucleophilic attack of the hydroxyl group of Ser117 on the carbonyl carbon of (+)-cocaine benzoyl ester and the dissociation of (+)-cocaine benzoyl ester. The first reaction step of deacylation of (+)-cocaine, which is identical to that of (-)-cocaine, is rate-determining, indicating that CocE-catalyzed hydrolyses of (+)- and (-)-cocaine have a common rate-determining step. The computational results predict that the catalytic rate constant of CocE against (+)-cocaine should be the same as that of CocE against (-)-cocaine, in contrast with the remarkable difference between human butyrylcholinesterase-catalyzed hydrolyses of (+)- and (-)-cocaine. The prediction has been confirmed by experimental kinetic analysis on CocE-catalyzed hydrolysis of (+)-cocaine in comparison with CocE-catalyzed hydrolysis of (-)-cocaine. The determined common rate-determining step indicates that rational design of a high-activity mutant of CocE should be focused on the first reaction step of the deacylation. Furthermore, the obtained mechanistic insights into the detailed differences in the acylation between the (+)- and (-)-cocaine hydrolyses provide indirect clues for rational design of amino acid mutations that could more favorably stabilize the rate-determining transition state in the deacylation and, thus, improve the catalytic activity of CocE. This study provides a valuable mechanistic base for rational design of an improved esterase for therapeutic treatment of cocaine abuse.
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Affiliation(s)
| | | | - Wenchao Yang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536
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23
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Collins GT, Carey KA, Narasimhan D, Nichols J, Berlin AA, Lukacs NW, Sunahara RK, Woods JH, Ko MC. Amelioration of the cardiovascular effects of cocaine in rhesus monkeys by a long-acting mutant form of cocaine esterase. Neuropsychopharmacology 2011; 36:1047-59. [PMID: 21289605 PMCID: PMC3076304 DOI: 10.1038/npp.2010.242] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A long-acting mutant form of a naturally occurring bacterial cocaine esterase (T172R/G173Q CocE; double mutant CocE (DM CocE)) has previously been shown to antagonize the reinforcing, convulsant, and lethal effects of cocaine in rodents. However, the effectiveness and therapeutic characteristics of DM CocE in nonhuman primates, in a more clinically relevant context, are unknown. The current studies were aimed at (1) characterizing the cardiovascular effects of cocaine in freely moving rhesus monkeys, (2) evaluating the capacity of DM CocE to ameliorate these cocaine-induced cardiovascular effects when administered 10 min after cocaine, and (3) assessing the immunological responses of monkeys to DM CocE following repeated administration. Intravenous administration of cocaine produced dose-dependent increases in mean arterial pressure (MAP) and heart rate (HR) that persisted throughout the 2-h observation period following a dose of 3.2 mg/kg cocaine. Cocaine failed to produce reliable changes in electrocardiograph (ECG) parameters, body temperature, and locomotor activity. DM CocE produced a rapid and dose-dependent amelioration of the cardiovascular effects, with saline-like MAP measures restored within 5-10 min, and saline-like HR measures restored within 20-40 min of DM CocE administration. Although administration of DM CocE produced increases in anti-CocE antibodies, they did not appear to have a neutralizing effect on the capacity of DM CocE to reverse the cardiovascular effects of cocaine. In conclusion, these findings in monkeys provide strong evidence to suggest that highly efficient cocaine esterases, such as DM CocE, can provide a potential therapeutic option for treatment of acute cocaine intoxication in humans.
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Affiliation(s)
- Gregory T Collins
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Kathy A Carey
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Diwahar Narasimhan
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Joseph Nichols
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Aaron A Berlin
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Nicholas W Lukacs
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Roger K Sunahara
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - James H Woods
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Mei-Chuan Ko
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA,Department of Pharmacology, University of Michigan Medical School, 1301 MSRB III, 1150 West Medical Center Drive, Ann Arbor, MI 48109-0632, USA. Tel: +1 734 647 3119, Fax: +1 734 764 7118, E-mail:
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Morin A, Meiler J, Mizoue LS. Computational design of protein-ligand interfaces: potential in therapeutic development. Trends Biotechnol 2011; 29:159-66. [PMID: 21295366 DOI: 10.1016/j.tibtech.2011.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2010] [Revised: 12/22/2010] [Accepted: 01/05/2011] [Indexed: 01/16/2023]
Abstract
Computational design of protein-ligand interfaces finds optimal amino acid sequences within a small-molecule binding site of a protein for tight binding of a specific small molecule. It requires a search algorithm that can rapidly sample the vast sequence and conformational space, and a scoring function that can identify low energy designs. This review focuses on recent advances in computational design methods and their application to protein-small molecule binding sites. Strategies for increasing affinity, altering specificity, creating broad-spectrum binding, and building novel enzymes from scratch are described. Future prospects for applications in drug development are discussed, including limitations that will need to be overcome to achieve computational design of protein therapeutics with novel modes of action.
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Affiliation(s)
- Andrew Morin
- Departments of Chemistry, Pharmacology, and Biomedical Informatics, Vanderbilt University, 7330 Stevenson Center, Station B 351822, Nashville, TN 37235, USA
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25
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Xue L, Ko MC, Tong M, Yang W, Hou S, Fang L, Liu J, Zheng F, Woods JH, Tai HH, Zhan CG. Design, preparation, and characterization of high-activity mutants of human butyrylcholinesterase specific for detoxification of cocaine. Mol Pharmacol 2011; 79:290-7. [PMID: 20971807 PMCID: PMC3033707 DOI: 10.1124/mol.110.068494] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2010] [Accepted: 10/22/2010] [Indexed: 11/22/2022] Open
Abstract
Cocaine is a widely abused drug without a U.S. Food and Drug Administration-approved medication. There is a recognized, promising anticocaine medication to accelerate cocaine metabolism, producing biologically inactive metabolites via a route similar to the primary cocaine-metabolizing pathway [i.e., cocaine hydrolysis catalyzed by butyrylcholinesterase (BChE) in plasma]. An ideal, therapeutically valuable mutant of human BChE should have not only a significantly improved catalytic activity against (-)-cocaine but also certain selectivity for (-)-cocaine over neurotransmitter acetylcholine (ACh), such that one would not expect systemic administration of the BChE mutant to interrupt cholinergic transmission. The present study accounting for the mutation-caused changes of the catalytic activities of BChE against both (-)-cocaine and ACh by means of molecular modeling and site-directed mutagenesis has led to identification of three BChE mutants that have not only a considerably improved catalytic efficiency against (-)-cocaine but also the desirable selectivity for (-)-cocaine over ACh. Two representative BChE mutants have been confirmed to be potent in actual protection of mice from acute toxicity (convulsion and lethality) of a lethal dose of cocaine (180 mg/kg). Pretreatment with the BChE mutant (i.e., 1 min before cocaine administration) dose-dependently protected mice against cocaine-induced convulsions and lethality. In particular, all mice pretreated with the mutant (e.g., 0.02 mg or more of A199S/F227A/S287G/A328W/E441D BChE) survived. The in vivo data reveal the primary factor (i.e., the relative catalytic efficiency), determining the efficacy in practical protection of mice from the acute cocaine toxicity and future direction for further improving the efficacy of the enzyme in the cocaine overdose treatment.
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Affiliation(s)
- Liu Xue
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street Lexington, KY 40536, USA
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26
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Abstract
“Recent progress in the study of cocaine-metabolizing enzymes demonstrates that enzyme-therapy approaches using appropriately designed enzymes show promise for the treatment of drug overdose and addiction.”
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Affiliation(s)
- Fang Zheng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536, USA
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27
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Narasimhan D, Nance MR, Gao D, Ko MC, Macdonald J, Tamburi P, Yoon D, Landry DM, Woods JH, Zhan CG, Tesmer JJ, Sunahara RK. Structural analysis of thermostabilizing mutations of cocaine esterase. Protein Eng Des Sel 2010; 23:537-47. [PMID: 20436035 PMCID: PMC2920302 DOI: 10.1093/protein/gzq025] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2009] [Revised: 02/22/2010] [Accepted: 03/18/2010] [Indexed: 11/14/2022] Open
Abstract
Cocaine is considered to be the most addictive of all substances of abuse and mediates its effects by inhibiting monoamine transporters, primarily the dopamine transporters. There are currently no small molecules that can be used to combat its toxic and addictive properties, in part because of the difficulty of developing compounds that inhibit cocaine binding without having intrinsic effects on dopamine transport. Most of the effective cocaine inhibitors also display addictive properties. We have recently reported the use of cocaine esterase (CocE) to accelerate the removal of systemic cocaine and to prevent cocaine-induced lethality. However, wild-type CocE is relatively unstable at physiological temperatures (tau(1/2) approximately 13 min at 37 degrees C), presenting challenges for its development as a viable therapeutic agent. We applied computational approaches to predict mutations to stabilize CocE and showed that several of these have increased stability both in vitro and in vivo, with the most efficacious mutant (T172R/G173Q) extending half-life up to 370 min. Here we present novel X-ray crystallographic data on these mutants that provide a plausible model for the observed enhanced stability. We also more extensively characterize the previously reported variants and report on a new stabilizing mutant, L169K. The improved stability of these engineered CocE enzymes will have a profound influence on the use of this protein to combat cocaine-induced toxicity and addiction in humans.
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Affiliation(s)
| | - Mark R. Nance
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Daquan Gao
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
| | | | | | | | | | | | | | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
| | - John J.G. Tesmer
- Department of Pharmacology and
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
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28
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Brim RL, Nance MR, Youngstrom DW, Narasimhan D, Zhan CG, Tesmer JJG, Sunahara RK, Woods JH. A thermally stable form of bacterial cocaine esterase: a potential therapeutic agent for treatment of cocaine abuse. Mol Pharmacol 2010; 77:593-600. [PMID: 20086035 DOI: 10.1124/mol.109.060806] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Rhodococcal cocaine esterase (CocE) is an attractive potential treatment for both cocaine overdose and cocaine addiction. CocE directly degrades cocaine into inactive products, whereas traditional small-molecule approaches require blockade of the inhibitory action of cocaine on a diverse array of monoamine transporters and ion channels. The usefulness of wild-type (wt) cocaine esterase is hampered by its inactivation at 37 degrees C. Herein, we characterize the most thermostable form of this enzyme to date, CocE-L169K/G173Q. In vitro kinetic analyses reveal that CocE-L169K/G173Q displays a half-life of 2.9 days at 37 degrees C, which represents a 340-fold improvement over wt and is 15-fold greater than previously reported mutants. Crystallographic analyses of CocE-L169K/G173Q, determined at 1.6-A resolution, suggest that stabilization involves enhanced domain-domain interactions involving van der Waals interactions and hydrogen bonding. In vivo rodent studies reveal that intravenous pretreatment with CocE-L169K/G173Q in mice provides protection from cocaine-induced lethality for longer time periods before cocaine administration than wt CocE. Furthermore, intravenous administration (pretreatment) of CocE-L169K/G173Q prevents self-administration of cocaine in a time-dependent manner. Termination of the in vivo effects of CoCE seems to be dependent on, but not proportional to, its clearance from plasma as its half-life is approximately 2.3 h and similar to that of wt CocE (2.2 h). Taken together these data suggest that CocE-L169K/G173Q possesses many of the properties of a biological therapeutic for treating cocaine abuse but requires additional development to improve its serum half-life.
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Affiliation(s)
- Remy L Brim
- Department of Pharmacology, University of Michigan Medical School, 1301 Medical Sciences Research Building III, 1150 W Medical Center Drive, Ann Arbor, MI 48109-0600, USA
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29
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Wood SK, Narasimhan D, Cooper Z, Sunahara RK, Woods JH. Prevention and reversal by cocaine esterase of cocaine-induced cardiovascular effects in rats. Drug Alcohol Depend 2010; 106:219-29. [PMID: 19800183 PMCID: PMC3349347 DOI: 10.1016/j.drugalcdep.2009.09.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 09/02/2009] [Accepted: 09/02/2009] [Indexed: 11/25/2022]
Abstract
The present study is the first to utilize bacterial cocaine esterase (CocE) to increase elimination of a lethal dose of cocaine and evaluate its cardioprotective effects. Rats received one of 5 treatments: CocE 1 min after saline; CocE 1 min after a lethal i.p. dose of cocaine; saline 1 min after a lethal i.p. dose of cocaine; CocE immediately after observing a cocaine-induced convulsion; and CocE 1 min after observing a cocaine-induced convulsion. Measures were taken of ECG, blood pressure, and cardiac troponin I (cTnI). The specificity of CocE against cocaine was determined by evaluating its actions against the cocaine analogue, WIN-35,065-2, which lacks an ester attack point for CocE. In addition, CocE's effects were compared with those of midazolam, a benzodiazepine often used to manage cocaine overdose. Whereas CocE alone had negligible cardiovascular effects, it blocked or reversed cocaine-induced QRS complex widening, increased QTc interval, ST elevation, bradycardia, and hypertension. When administered 1 min after cocaine, CocE inhibited myocardial damage; however, administered 1 min after a cocaine-induced convulsion (approximately 40s before cocaine-induced death), CocE did not block cTnI release, but did restore cardiac function. Midazolam blocked convulsions, but exhibited inadequate protection against cocaine-induced cardiotoxicity. The majority of rats given cocaine plus midazolam died. CocE did not prevent the lethal cardiovascular effects of WIN-35,065-2. In all likelihood, CocE rapidly and specifically reduced the body burden of cocaine and inhibited or reversed the cardiovascular consequences of high-dose cocaine. These results support CocE as a potential therapeutic avenue in cocaine overdose.
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Affiliation(s)
| | | | | | | | - James H. Woods
- Corresponding author at: Department of Pharmacology, The University of Michigan Medical School, 1301 Medical Science Research Building III, 1150 W. Medical Center Dr., Ann Arbor, MI 48109-0632, USA. Tel.: +1 734 764 9133; fax: +1 734 764 7118. (J.H. Woods).
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30
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PEGylation of bacterial cocaine esterase for protection against protease digestion and immunogenicity. J Control Release 2009; 142:174-9. [PMID: 19857534 DOI: 10.1016/j.jconrel.2009.10.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 09/15/2009] [Accepted: 10/13/2009] [Indexed: 11/20/2022]
Abstract
Enhancing cocaine metabolism by administration of cocaine esterase (CocE) has been considered as a promising treatment strategy for cocaine overdose and addiction, as CocE is the most efficient native enzyme yet identified for metabolizing the naturally occurring cocaine. A major obstacle to the clinical application of CocE, however, lies in its thermo-instability, rapid degradation by circulating proteases, and potential immunogenicity. PEGylation, namely by modifying a protein or peptide compound via attachment of polyethylene glycol (PEG) chains, has been proven to overcome such problems and was therefore exploited in this CocE investigation. The PEG-CocE conjugates prepared in this study showed a purity of greater than 93.5%. Attachment of PEG to CocE apparently inhibited the binding of anti-CocE antibodies to the conjugate, as demonstrated by the enzyme-linked immunosorbent assay (ELISA) assay. In addition, PEGylation yielded protection to CocE against thermal degradation and protease digestion. Furthermore, preliminary in vivo results suggested that, similarly to native CocE, the PEG-CocE conjugates were able to protect animals from cocaine-induced toxic effects. Overall, this study provides evidence that the PEGylation may serve as a tool to prolong CocE functionality in the circulation and reduce its potential immunogenicity.
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31
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Collins GT, Brim RL, Narasimhan D, Ko MC, Sunahara RK, Zhan CG, Woods JH. Cocaine esterase prevents cocaine-induced toxicity and the ongoing intravenous self-administration of cocaine in rats. J Pharmacol Exp Ther 2009; 331:445-55. [PMID: 19710369 DOI: 10.1124/jpet.108.150029] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cocaine esterase (CocE) is a naturally occurring bacterial enzyme, is a very efficient protein catalyst for the hydrolysis of cocaine, and has previously been shown to protect rodents from the lethal effects of cocaine. The current studies were aimed at evaluating the capacity of a longer acting mutant form (CocE T172R/G173Q; DM CocE) of CocE to protect against the lethal effects of cocaine, and alter ongoing intravenous cocaine self-administration in rats. A dose-response analysis revealed a dose-dependent suppression of cocaine-reinforced responding with 1.0 mg of CocE T172R/G173Q producing saline-like rates of responding. The effects of 1.0 mg of CocE T172R/G173Q on cocaine-reinforced responding were then compared with responding when saline was available for injection, whereas the selectivity of CocE T172R/G173Q's effects was assessed by evaluating the effects of 1.0 mg of CocE T172R/G173Q on (-)-2beta-carbomethoxy-3beta-phenyltropane (WIN-35065-2)- and food-reinforced responding. Although 1.0 mg of CocE T172R/G173Q suppressed responding maintained by 0.1 mg/kg/injection cocaine, a significant increase in responding was observed when responding was maintained by 1.0 mg/kg/injection cocaine, resulting in a 10-fold rightward shift in the dose-response curve for cocaine self-administration at a dose that did not significantly alter responding maintained by either WIN-35065-2 or food. These findings demonstrate that a long-acting form of CocE is effective at abruptly reducing the ongoing self-administration of low doses of cocaine, and provides a robust antagonism of cocaine's reinforcing effects. Furthermore, these studies provide strong evidence for the potential usefulness of a suitable, stable, and long-acting form of CocE as a pharmacotherapy for cocaine abuse in humans.
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Affiliation(s)
- Gregory T Collins
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0632, USA
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32
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Liu J, Hamza A, Zhan CG. Fundamental reaction mechanism and free energy profile for (-)-cocaine hydrolysis catalyzed by cocaine esterase. J Am Chem Soc 2009; 131:11964-75. [PMID: 19642701 PMCID: PMC2738781 DOI: 10.1021/ja903990p] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The fundamental reaction mechanism of cocaine esterase (CocE)-catalyzed hydrolysis of (-)-cocaine and the corresponding free energy profile have been studied by performing pseudobond first-principles quantum mechanical/molecular mechanical free energy (QM/MM-FE) calculations. On the basis of the QM/MM-FE results, the entire hydrolysis reaction consists of four reaction steps, including the nucleophilic attack on the carbonyl carbon of (-)-cocaine benzoyl ester by the hydroxyl group of Ser117, dissociation of (-)-cocaine benzoyl ester, nucleophilic attack on the carbonyl carbon of (-)-cocaine benzoyl ester by water, and finally dissociation between the (-)-cocaine benzoyl group and Ser117 of CocE. The third reaction step involving the nucleophilic attack of a water molecule was found to be rate-determining, which is remarkably different from (-)-cocaine hydrolysis catalyzed by wild-type butyrylcholinesterase (BChE; where the formation of the prereactive BChE-(-)-cocaine complex is rate-determining) or its mutants containing Tyr332Gly or Tyr332Ala mutation (where the first chemical reaction step is rate-determining). Besides, the role of Asp259 in the catalytic triad of CocE does not follow the general concept of the "charge-relay system" for all serine esterases. The free energy barrier calculated for the rate-determining step of CocE-catalyzed hydrolysis of (-)-cocaine is 17.9 kcal/mol, which is in good agreement with the experimentally derived activation free energy of 16.2 kcal/mol. In the present study, where many sodium ions are present, the effects of counterions are found to be significant in determining the free energy barrier. The finding of the significant effects of counterions on the free energy barrier may also be valuable in guiding future mechanistic studies on other charged enzymes.
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Affiliation(s)
- Junjun Liu
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536
| | - Adel Hamza
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536
| | - Chang-Guo Zhan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, KY 40536
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33
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Gao Y, Brimijoin S. Lasting reduction of cocaine action in neostriatum--a hydrolase gene therapy approach. J Pharmacol Exp Ther 2009; 330:449-57. [PMID: 19478136 DOI: 10.1124/jpet.109.152231] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We previously found that a quadruple mutant cocaine hydrolase derived from human butyrylcholinesterase [termed cocaine esterase (CocE)] can suppress or reverse cocaine toxicity and abolish drug-primed reinstatement in rats. Here, we examined whether gene transfer of CocE reduces cocaine actions in brain reward centers. Early experiments used a standard, early region 1-deleted adenoviral vector, which, after intravenous delivery of 10(10) plaque-forming units, caused plasma cocaine hydrolase activity to rise 25,000-fold between day 4 and day 7. During this period, under a protocol that typically induces FosB expression in the caudate nucleus, these rats and unprotected controls given only empty vector or saline were subjected to repeated twice-daily injections of cocaine (30 mg/kg i.p.). Immunohistochemistry of the neostriatum on day 7 showed many FosB-reactive nuclei in unprotected rats but few if any in rats pretreated with active vector, which resembled rats never exposed to cocaine. Western blots confirmed this result. In contrast there was a more localized protection against cocaine-elicited FosB induction when hydrolase vector was injected directly into the ventral striatum, which generated high transgene expression in many neurons of the target area. Similar results were obtained with systemic and local injection of a more efficient helper-dependent adenoviral vector, which transduced high levels of hydrolase for at least 2 months, with lesser expression continued up to 1 year. Behavioral tests are now warranted to determine whether such effects can reduce drug-seeking behavior and lower the probability of relapse.
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Affiliation(s)
- Yang Gao
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota 55905, USA
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34
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Effects of cocaine esterase following its repeated administration with cocaine in mice. Drug Alcohol Depend 2009; 101:202-9. [PMID: 19217723 PMCID: PMC2693214 DOI: 10.1016/j.drugalcdep.2009.01.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 12/29/2008] [Accepted: 01/15/2009] [Indexed: 11/21/2022]
Abstract
BACKGROUND A bacterial cocaine esterase (CocE) produces robust protection and reversal of cocaine toxicity. The aim of this study was to investigate how effectiveness of CocE was changed following its repeated administration together with cocaine. METHODS Cocaine toxicity was quantified by measuring the occurrence of convulsions and lethality in mice. Immunologic responses of CocE were determined using ELISA. In the protection experiment, i.v. CocE 0.3mg was given 1min before a lethal dose of i.p. cocaine 180mg/kg. In the rescue experiment, i.v. CocE 0.3mg was given 1min after the occurrence of convulsions elicited by i.p. cocaine 100mg/kg. In both treatment paradigms, four trials were conducted in the same animals with a 2-week interval. RESULTS CocE retained its effectiveness to protect or rescue mice during the first two trials and these mice did not show an immune response. In contrast, CocE's effectiveness was gradually reduced in the last two trials, accompanied by 10- and 100-fold increases in anti-CocE antibody titers. Nevertheless, effectiveness of CocE could be partially recovered by increasing the dose of CocE. In addition, escalating the dose of CocE from the minimum effective dose for repeated administration could also retain CocE's effectiveness longer and slow the production of anti-CocE antibodies. CONCLUSIONS These results indicate that CocE is a weak antigen and it can maintain its protective and rescuing ability initially against cocaine-induced toxicity. Decreased effectiveness of CocE following repeated use can be partially improved by adjusting the dose and frequency of CocE treatment.
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35
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Jutkiewicz EM, Baladi MG, Cooper ZD, Narasimhan D, Sunahara RK, Woods JH. A bacterial cocaine esterase protects against cocaine-induced epileptogenic activity and lethality. Ann Emerg Med 2008; 54:409-20. [PMID: 19013687 DOI: 10.1016/j.annemergmed.2008.09.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Revised: 09/12/2008] [Accepted: 09/23/2008] [Indexed: 10/21/2022]
Abstract
STUDY OBJECTIVE Cocaine toxicity results in cardiovascular complications, seizures, and death and accounts for approximately 20% of drug-related emergency department visits every year. Presently, there are no treatments to eliminate the toxic effects of cocaine. The present study hypothesizes that a bacterial cocaine esterase with high catalytic efficiency would provide rapid and robust protection from cocaine-induced convulsions, epileptogenic activity, and lethality. METHODS Cocaine-induced paroxysmal activity and convulsions were evaluated in rats surgically implanted with radiotelemetry devices (N=6 per treatment group). Cocaine esterase was administered 1 minute after a lethal dose of cocaine or after cocaine-induced convulsions to determine the ability of the enzyme to prevent or reverse, respectively, the effects of cocaine. RESULTS The cocaine esterase prevented all cocaine-induced electroencephalographic changes and lethality. This effect was specific for cocaine because the esterase did not prevent convulsions and death induced by a cocaine analog, (-)-2beta-carbomethoxy-3beta-phenyltropane. The esterase prevented lethality even after cocaine-induced convulsions occurred. In contrast, the short-acting benzodiazepine, midazolam, prevented cocaine-induced convulsions but not the lethal effects of cocaine. CONCLUSION The data showed that cocaine esterase successfully degraded circulating cocaine to prevent lethality and that cocaine-induced convulsions alone are not responsible for the lethal effects of cocaine in this model. Therefore, further investigation into the use of cocaine esterase for treating cocaine overdose and its toxic effects is warranted.
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Affiliation(s)
- Emily M Jutkiewicz
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109-0632, USA.
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36
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Gao D, Narasimhan DL, Macdonald J, Brim R, Ko MC, Landry DW, Woods JH, Sunahara RK, Zhan CG. Thermostable variants of cocaine esterase for long-time protection against cocaine toxicity. Mol Pharmacol 2008; 75:318-23. [PMID: 18987161 DOI: 10.1124/mol.108.049486] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Enhancing cocaine metabolism by administration of cocaine esterase (CocE) has been recognized as a promising treatment strategy for cocaine overdose and addiction, because CocE is the most efficient native enzyme for metabolizing the naturally occurring cocaine yet identified. A major obstacle to the clinical application of CocE is the thermoinstability of native CocE with a half-life of only a few minutes at physiological temperature (37 degrees C). Here we report thermostable variants of CocE developed through rational design using a novel computational approach followed by in vitro and in vivo studies. This integrated computational-experimental effort has yielded a CocE variant with a approximately 30-fold increase in plasma half-life both in vitro and in vivo. The novel design strategy can be used to develop thermostable mutants of any protein.
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Affiliation(s)
- Daquan Gao
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536, USA
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37
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A cocaine hydrolase engineered from human butyrylcholinesterase selectively blocks cocaine toxicity and reinstatement of drug seeking in rats. Neuropsychopharmacology 2008; 33:2715-25. [PMID: 18199998 PMCID: PMC2562914 DOI: 10.1038/sj.npp.1301666] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Successive rational mutations of human butyrylcholinesterase (BChE) followed by fusion to human serum albumin have yielded an efficient hydrolase that offers realistic options for therapy of cocaine overdose and abuse. This albumin-BChE prevented seizures in rats given a normally lethal cocaine injection (100 mg/kg, i.p.), lowered brain cocaine levels even when administered after the drug, and provided rescue after convulsions commenced. Moreover, it selectively blocked cocaine-induced reinstatement of drug seeking in rats that had previously self-administered cocaine. The enzyme treatment was well tolerated and may be worth exploring for clinical application in humans.
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38
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Zheng F, Yang W, Ko MC, Liu J, Cho H, Gao D, Tong M, Tai HH, Woods JH, Zhan CG. Most efficient cocaine hydrolase designed by virtual screening of transition states. J Am Chem Soc 2008; 130:12148-55. [PMID: 18710224 DOI: 10.1021/ja803646t] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cocaine is recognized as the most reinforcing of all drugs of abuse. There is no anticocaine medication available. The disastrous medical and social consequences of cocaine addiction have made the development of an anticocaine medication a high priority. It has been recognized that an ideal anticocaine medication is one that accelerates cocaine metabolism producing biologically inactive metabolites via a route similar to the primary cocaine-metabolizing pathway, i.e., cocaine hydrolysis catalyzed by plasma enzyme butyrylcholinesterase (BChE). However, wild-type BChE has a low catalytic efficiency against the abused cocaine. Design of a high-activity enzyme mutant is extremely challenging, particularly when the chemical reaction process is rate-determining for the enzymatic reaction. Here we report the design and discovery of a high-activity mutant of human BChE by using a novel, systematic computational design approach based on transition-state simulations and activation energy calculations. The novel computational design approach has led to discovery of the most efficient cocaine hydrolase, i.e., a human BChE mutant with an approximately 2000-fold improved catalytic efficiency, promising for therapeutic treatment of cocaine overdose and addiction as an exogenous enzyme in human. The encouraging discovery resulted from the computational design not only provides a promising anticocaine medication but also demonstrates that the novel, generally applicable computational design approach is promising for rational enzyme redesign and drug discovery.
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Affiliation(s)
- Fang Zheng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, Kentucky 40536, USA
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39
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Gao Y, LaFleur D, Shah R, Zhao Q, Singh M, Brimijoin S. An albumin-butyrylcholinesterase for cocaine toxicity and addiction: catalytic and pharmacokinetic properties. Chem Biol Interact 2008; 175:83-7. [PMID: 18514640 DOI: 10.1016/j.cbi.2008.04.024] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 03/31/2008] [Accepted: 04/02/2008] [Indexed: 11/30/2022]
Abstract
Butyrylcholinesterase (BChE, EC 3.1.1.8) is important in human cocaine metabolism despite its limited ability to hydrolyze this drug. Efforts to improve the catalytic efficiency of this enzyme have led to a quadruple mutant cocaine hydrolase, "CocH", that in animal models of addiction appears promising for treatment of overdose and relapse. We incorporated the CocH mutations into a BChE-albumin fusion protein, "Albu-CocH", and evaluated the pharmacokinetics of the enzyme after i.v. injection in rats. As assessed from the time course of cocaine hydrolyzing activity in plasma, Albu-CocH redistributed into extracellular fluid (16% of estimated total body water) with a t(1/2) of 0.66h and it underwent elimination with a t(1/2) of 8h. These results indicate that the enzyme has ample stability for short-term applications and may be suitable for longer-term treatment as well. Present data also confirm the markedly enhanced power of Albu-CocH for cocaine hydrolysis and they support the view that Albu-CocH might prove valuable in treating phenomena associated with cocaine abuse.
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Affiliation(s)
- Yang Gao
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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