1
|
Luan M, Xu Y, Zhang X, Li D, Yan M, Hou G, Meng Q, Zhao F, Zhao F. Design and synthesis of novel aza-ursolic acid derivatives: in vitro cytotoxicity and nitric oxide release inhibitory activity. Future Med Chem 2022; 14:535-555. [PMID: 35286228 DOI: 10.4155/fmc-2021-0319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Aim: Inducible nitric oxide synthase (iNOS) is a validated target for anti-inflammatory treatment. Based on the authors' previous work, novel aza-ursolic acid derivatives were designed and synthesized and their inhibitory activities against lipopolysaccharide (LPS)-induced nitric oxide (NO) release from RAW264.7 cells was evaluated. Materials & results: 16 novel derivatives were screened for their in vitro inhibitory activity against NO release using Griess assays and the cytotoxicity was evaluated using MTT assays. The presence of furoxan joined to the A-ring of ursolic acid and N-methylpiperazine groups in the lead compound was identified for anti-inflammatory activity, and compound 21b showed 94.96% inhibition of NO release at 100 μM with an IC50 value of 8.58 μM. Conclusion: Compound 21b has potential anti-inflammatory activity with low cytotoxicity that warrants further preclinical study and evaluation.
Collapse
Affiliation(s)
- Mingzhu Luan
- School of Pharmacy, Key Laboratory of Molecular Pharmacology & Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System & Biotech Drugs in Universities of Shandong, Yantai University, Yantai, 264005, PR China
| | - Yaoyao Xu
- School of Pharmacy, Key Laboratory of Molecular Pharmacology & Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System & Biotech Drugs in Universities of Shandong, Yantai University, Yantai, 264005, PR China
| | - Xiaofan Zhang
- School of Pharmacy, Key Laboratory of Molecular Pharmacology & Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System & Biotech Drugs in Universities of Shandong, Yantai University, Yantai, 264005, PR China
| | - Dalei Li
- School of Pharmacy, Key Laboratory of Molecular Pharmacology & Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System & Biotech Drugs in Universities of Shandong, Yantai University, Yantai, 264005, PR China
| | - Mengjun Yan
- Yantai Raphael Biotechnology Co., Ltd, Yantai, 264043, PR China
| | - Guige Hou
- School of Basic Medical Sciences, Binzhou Medical University, Yantai, 264003, PR China
| | - Qingguo Meng
- School of Pharmacy, Key Laboratory of Molecular Pharmacology & Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System & Biotech Drugs in Universities of Shandong, Yantai University, Yantai, 264005, PR China
| | - Feng Zhao
- School of Pharmacy, Key Laboratory of Molecular Pharmacology & Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System & Biotech Drugs in Universities of Shandong, Yantai University, Yantai, 264005, PR China
| | - Fenglan Zhao
- School of Pharmacy, Key Laboratory of Molecular Pharmacology & Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System & Biotech Drugs in Universities of Shandong, Yantai University, Yantai, 264005, PR China
| |
Collapse
|
2
|
Keller TCS, Lechauve C, Keller AS, Brooks S, Weiss MJ, Columbus L, Ackerman H, Cortese-Krott MM, Isakson BE. The role of globins in cardiovascular physiology. Physiol Rev 2022; 102:859-892. [PMID: 34486392 PMCID: PMC8799389 DOI: 10.1152/physrev.00037.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 12/11/2022] Open
Abstract
Globin proteins exist in every cell type of the vasculature, from erythrocytes to endothelial cells, vascular smooth muscle cells, and peripheral nerve cells. Many globin subtypes are also expressed in muscle tissues (including cardiac and skeletal muscle), in other organ-specific cell types, and in cells of the central nervous system (CNS). The ability of each of these globins to interact with molecular oxygen (O2) and nitric oxide (NO) is preserved across these contexts. Endothelial α-globin is an example of extraerythrocytic globin expression. Other globins, including myoglobin, cytoglobin, and neuroglobin, are observed in other vascular tissues. Myoglobin is observed primarily in skeletal muscle and smooth muscle cells surrounding the aorta or other large arteries. Cytoglobin is found in vascular smooth muscle but can also be expressed in nonvascular cell types, especially in oxidative stress conditions after ischemic insult. Neuroglobin was first observed in neuronal cells, and its expression appears to be restricted mainly to the CNS and the peripheral nervous system. Brain and CNS neurons expressing neuroglobin are positioned close to many arteries within the brain parenchyma and can control smooth muscle contraction and thus tissue perfusion and vascular reactivity. Overall, reactions between NO and globin heme iron contribute to vascular homeostasis by regulating vasodilatory NO signals and scavenging reactive species in cells of the mammalian vascular system. Here, we discuss how globin proteins affect vascular physiology, with a focus on NO biology, and offer perspectives for future study of these functions.
Collapse
Affiliation(s)
- T C Stevenson Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Christophe Lechauve
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Alexander S Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Steven Brooks
- Physiology Unit, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Rockville, Maryland
| | - Mitchell J Weiss
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Linda Columbus
- Department of Chemistry, University of Virginia, Charlottesville, Virginia
| | - Hans Ackerman
- Physiology Unit, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Rockville, Maryland
| | - Miriam M Cortese-Krott
- Myocardial Infarction Research Laboratory, Department of Cardiology, Pulmonology, and Angiology, Medical Faculty, Heinrich Heine University of Düsseldorf, Düsseldorf, Germany
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia
| |
Collapse
|
3
|
Boumezber S, Yelekçi K. Screening of novel and selective inhibitors for neuronal nitric oxide synthase (nNOS) via structure-based drug design techniques. J Biomol Struct Dyn 2022; 41:3607-3629. [PMID: 35322764 DOI: 10.1080/07391102.2022.2054471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
NO, or nitric oxide, is produced by a family of enzymes called nitric oxide synthase (NOS) from L-arginine. NO regulates many physiological functions such as smooth muscle relaxation, immune defense, and memory function. The overproduction of NO by the neuronal isoform of nitric oxide synthase (nNOS) is implicated in neurodegeneration and neuropathic pain, making nNOS inhibition a promising therapeutic approach. Many developed nNOS inhibitors, generally L-arginine mimetics, have some issues in selectivity and bioavailability. According to earlier studies, targeting nNOS has the advantage of decreasing excess NO in the brain while avoiding the negative consequences of inhibiting the two isozymes: endothelial NOS (eNOS) and inducible NOS (iNOS). This study applied structure-based virtual screening, molecular docking, and molecular dynamics simulations to design potent and selective inhibitors against nNOS over related isoforms (eNOS and iNOS) using human X-ray crystal structures of the NOS isoforms. It was discovered that some compounds displayed a very good inhibitory potency for hnNOS and moderate selectivity for the other isozymes, eNOS and iNOS, in addition to good solubility and desirable physiochemical properties. The compounds which showed good stability and selectivity with nNOS, such as ZINC000013485422, can be interesting and informative guidance for designing more potent human nNOS inhibitors.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Sarah Boumezber
- Department of Bioinformatics and Genetics, Faculty of Engineering and Natural Sciences, Kadir Has University, Istanbul, Turkey
| | - Kemal Yelekçi
- Department of Bioinformatics and Genetics, Faculty of Engineering and Natural Sciences, Kadir Has University, Istanbul, Turkey
| |
Collapse
|
4
|
Dao VTV, Elbatreek MH, Fuchß T, Grädler U, Schmidt HHHW, Shah AM, Wallace A, Knowles R. Nitric Oxide Synthase Inhibitors into the Clinic at Last. Handb Exp Pharmacol 2021; 264:169-204. [PMID: 32797331 DOI: 10.1007/164_2020_382] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The 1998 Nobel Prize in Medicine and Physiology for the discovery of nitric oxide, a nitrogen containing reactive oxygen species (also termed reactive nitrogen or reactive nitrogen/oxygen species) stirred great hopes. Clinical applications, however, have so far pertained exclusively to the downstream signaling of cGMP enhancing drugs such as phosphodiesterase inhibitors and soluble guanylate cyclase stimulators. All clinical attempts, so far, to inhibit NOS have failed even though preclinical models were strikingly positive and clinical biomarkers correlated perfectly. This rather casts doubt on our current way of target identification in drug discovery in general and our way of patient stratification based on correlating but not causal biomarkers or symptoms. The opposite, NO donors, nitrite and enhancing NO synthesis by eNOS/NOS3 recoupling in situations of NO deficiency, are rapidly declining in clinical relevance or hold promise but need yet to enter formal therapeutic guidelines, respectively. Nevertheless, NOS inhibition in situations of NO overproduction often jointly with enhanced superoxide (or hydrogen peroxide production) still holds promise, but most likely only in acute conditions such as neurotrauma (Stover et al., J Neurotrauma 31(19):1599-1606, 2014) and stroke (Kleinschnitz et al., J Cereb Blood Flow Metab 1508-1512, 2016; Casas et al., Proc Natl Acad Sci U S A 116(14):7129-7136, 2019). Conversely, in chronic conditions, long-term inhibition of NOS might be too risky because of off-target effects on eNOS/NOS3 in particular for patients with cardiovascular risks or metabolic and renal diseases. Nitric oxide synthases (NOS) and their role in health (green) and disease (red). Only neuronal/type 1 NOS (NOS1) has a high degree of clinical validation and is in late stage development for traumatic brain injury, followed by a phase II safety/efficacy trial in ischemic stroke. The pathophysiology of NOS1 (Kleinschnitz et al., J Cereb Blood Flow Metab 1508-1512, 2016) is likely to be related to parallel superoxide or hydrogen peroxide formation (Kleinschnitz et al., J Cereb Blood Flow Metab 1508-1512, 2016; Casas et al., Proc Natl Acad Sci U S A 114(46):12315-12320, 2017; Casas et al., Proc Natl Acad Sci U S A 116(14):7129-7136, 2019) leading to peroxynitrite and protein nitration, etc. Endothelial/type 3 NOS (NOS3) is considered protective only and its inhibition should be avoided. The preclinical evidence for a role of high-output inducible/type 2 NOS (NOS2) isoform in sepsis, asthma, rheumatic arthritis, etc. was high, but all clinical development trials in these indications were neutral despite target engagement being validated. This casts doubt on the role of NOS2 in humans in health and disease (hence the neutral, black coloring).
Collapse
Affiliation(s)
- Vu Thao-Vi Dao
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany
| | - Mahmoud H Elbatreek
- Department of Pharmacology and Personalised Medicine, MeHNS, FHML, Maastricht, The Netherlands.,Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Thomas Fuchß
- Takeda GmbH (former Nycomed/Altana Pharma), Konstanz, Germany
| | - Ulrich Grädler
- Takeda GmbH (former Nycomed/Altana Pharma), Konstanz, Germany
| | - Harald H H W Schmidt
- Department of Pharmacology and Personalised Medicine, MeHNS, FHML, Maastricht, The Netherlands
| | - Ajay M Shah
- King's College London British Heart Foundation Centre, School of Cardiovascular Medicine and Sciences, London, UK
| | - Alan Wallace
- Health and Life Sciences, Coventry University, Coventry, UK
| | - Richard Knowles
- Knowles Consulting Ltd., The Stevenage Bioscience Catalyst, Stevenage, UK.
| |
Collapse
|
5
|
Li J, Zheng H, Feng C. Deciphering mechanism of conformationally controlled electron transfer in nitric oxide synthases. FRONT BIOSCI-LANDMRK 2018; 23:1803-1821. [PMID: 29772530 PMCID: PMC11167721 DOI: 10.2741/4674] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Electron transfer is a fundamental process in life that is very often coupled to catalysis within redox enzymes through a stringent control of protein conformational movements. Mammalian nitric oxide synthase (NOS) proteins are redox flavo-hemoproteins consisting of multiple modular domains. The NOS enzyme is exquisitely regulated in vivo by its partner, the Ca2+ sensing protein calmodulin (CaM), to control production of nitric oxide (NO). The importance of functional domain motion in NOS regulation has been increasingly recognized. The significant size and flexibility of NOS is a tremendous challenge to the mechanistic studies. Herein recent applications of modern biophysical techniques to NOS problems have been critically analyzed. It is important to note that any current biophysical technique alone can only probe partial aspects of the conformational dynamics due to limitations in the technique itself and/or the sample preparations. It is necessary to combine the latest methods to comprehensively quantitate the key conformational aspects (conformational states and distribution, conformational change rates, and domain interacting interfaces) governing the electron transfer. This is to answer long-standing central questions about the NOS isoforms by defining how specific CaM-NOS interactions and regulatory elements underpin the distinct conformational behavior of the NOS isoform, which in turn determine unique electron transfer and NO synthesis properties. This review is not intended as comprehensive, but as a discussion of prospects that promise impact on important questions in the NOS enzymology field.
Collapse
Affiliation(s)
- Jinghui Li
- College of Pharmacy, University of New Mexico, Albuquerque, NM 87131, USA
| | - Huayu Zheng
- College of Pharmacy, University of New Mexico, Albuquerque, NM 87131, USA
| | - Changjian Feng
- University of New Mexico, MSC 09 5360, Albuquerque, NM 87131,
| |
Collapse
|
6
|
Cramer JT, Führing JI, Baruch P, Brütting C, Knölker HJ, Gerardy-Schahn R, Fedorov R. Decoding Allosteric Networks in Biocatalysts: Rational Approach to Therapies and Biotechnologies. ACS Catal 2018. [DOI: 10.1021/acscatal.7b03714] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Johannes T. Cramer
- Institute of Clinical Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
- Institute for Biophysical Chemistry/Research Division for Structural Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Jana I. Führing
- Institute of Clinical Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Petra Baruch
- Institute for Biophysical Chemistry/Research Division for Structural Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Christian Brütting
- Department of Chemistry, Technische Universität Dresden, Bergstrasse 66, 01069 Dresden, Germany
| | - Hans-Joachim Knölker
- Department of Chemistry, Technische Universität Dresden, Bergstrasse 66, 01069 Dresden, Germany
| | - Rita Gerardy-Schahn
- Institute of Clinical Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Roman Fedorov
- Institute for Biophysical Chemistry/Research Division for Structural Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| |
Collapse
|
7
|
Pensa AV, Cinelli MA, Li H, Chreifi G, Mukherjee P, Roman LJ, Martásek P, Poulos TL, Silverman RB. Hydrophilic, Potent, and Selective 7-Substituted 2-Aminoquinolines as Improved Human Neuronal Nitric Oxide Synthase Inhibitors. J Med Chem 2017; 60:7146-7165. [PMID: 28776992 DOI: 10.1021/acs.jmedchem.7b00835] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neuronal nitric oxide synthase (nNOS) is a target for development of antineurodegenerative agents. Most nNOS inhibitors mimic l-arginine and have poor bioavailability. 2-Aminoquinolines showed promise as bioavailable nNOS inhibitors but suffered from low human nNOS inhibition, low selectivity versus human eNOS, and significant binding to other CNS targets. We aimed to improve human nNOS potency and selectivity and reduce off-target binding by (a) truncating the original scaffold or (b) introducing a hydrophilic group to interrupt the lipophilic, promiscuous pharmacophore and promote interaction with human nNOS-specific His342. We synthesized both truncated and polar 2-aminoquinoline derivatives and assayed them against recombinant NOS enzymes. Although aniline and pyridine derivatives interact with His342, benzonitriles conferred the best rat and human nNOS inhibition. Both introduction of a hydrophobic substituent next to the cyano group and aminoquinoline methylation considerably improved isoform selectivity. Most importantly, these modifications preserved Caco-2 permeability and reduced off-target CNS binding.
Collapse
Affiliation(s)
- Anthony V Pensa
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Maris A Cinelli
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Huiying Li
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California , Irvine, California 92697-3900, United States
| | - Georges Chreifi
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California , Irvine, California 92697-3900, United States
| | - Paramita Mukherjee
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Linda J Roman
- Department of Biochemistry, University of Texas Health Science Center , San Antonio, Texas 78384-7760, United States
| | - Pavel Martásek
- Department of Biochemistry, University of Texas Health Science Center , San Antonio, Texas 78384-7760, United States.,Department of Pediatrics and Center for Applied Genomics, First School of Medicine, Charles University and BIOCEV 121 08 Prague, Czech Republic
| | - Thomas L Poulos
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California , Irvine, California 92697-3900, United States
| | - Richard B Silverman
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208-3113, United States
| |
Collapse
|
8
|
Mohammadi A, Abnosi MH, Pakyari R. Low Concentration of Sodium Nitroprusside Promotes Mesenchymal Stem Cell Viability and Proliferation Through Elevation of Metabolic Activity. AVICENNA JOURNAL OF MEDICAL BIOCHEMISTRY 2017. [DOI: 10.15171/ajmb.2017.02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background: Sodium nitroprusside (SNP) releases nitric oxide which has signaling role. Objectives: This study was conducted to understand the role of low concentration of SNP on viability, proliferation and biochemical properties of rat bone marrow mesenchymal stem cells (MSCs). Materials and Methods: MSCs were used to evaluate the viability and morphology in presence of SNP (1 to 100 µM) at 12, 24 and 36 hours. Then 10, 50 and 100 µM of SNP as well as 24 hours were selected for further study. Cell proliferation was investigated by colony forming assay and population doubling number (PDN). Calcium (Ca2+) potassium (K+) and sodium (Na+) level as well as activity of alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) were measured. Results: The MSCs viability increased when treatment with 1 and 10 µM at all the treatment periods while 90 and 100 µM caused significant reduction after 24 and 36 hours. Also 10 µM caused elevation whereas 50 and 100 µM showed reduction of proliferation ability. We observed morphological changes and significant reduction of all the investigated enzymes with 100 µM. Activity of ALT and AST were elevated with 10 µM after 24 hours, whereas LDH and ALP activities were not changed. Na+, K+ and Ca2+ was not changed due to 10 and 50 µM treatments, whereas 100 µM only elevated the level of calcium and sodium ions. Conclusions: Low concentration of SNP caused increase of viability and proliferation due to metabolic activity elevation. But the high concentration of SNP induced cell viability and proliferation reduction caused by metabolic and ionic imbalance as well as infrastructure alteration.
Collapse
Affiliation(s)
- Atefeh Mohammadi
- Department of Biology, Faculty of Sciences, Arak University, Arak, Iran
| | | | - Reza Pakyari
- Department of Biology, Faculty of Sciences, Arak University, Arak, Iran
| |
Collapse
|
9
|
Cinelli MA, Li H, Chreifi G, Poulos TL, Silverman RB. Nitrile in the Hole: Discovery of a Small Auxiliary Pocket in Neuronal Nitric Oxide Synthase Leading to the Development of Potent and Selective 2-Aminoquinoline Inhibitors. J Med Chem 2017; 60:3958-3978. [PMID: 28422508 PMCID: PMC5567828 DOI: 10.1021/acs.jmedchem.7b00259] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Neuronal nitric oxide synthase (nNOS) inhibition is a promising strategy to treat neurodegenerative disorders, but the development of nNOS inhibitors is often hindered by poor pharmacokinetics. We previously developed a class of membrane-permeable 2-aminoquinoline inhibitors and later rearranged the scaffold to decrease off-target binding. However, the resulting compounds had decreased permeability, low human nNOS activity, and low selectivity versus human eNOS. In this study, 5-substituted phenyl ether-linked aminoquinolines and derivatives were synthesized and assayed against purified NOS isoforms. 5-Cyano compounds are especially potent and selective rat and human nNOS inhibitors. Activity and selectivity are mediated by the binding of the cyano group to a new auxiliary pocket in nNOS. Potency was enhanced by methylation of the quinoline and by introduction of simple chiral moieties, resulting in a combination of hydrophobic and auxiliary pocket effects that yielded high (∼500-fold) n/e selectivity. Importantly, the Caco-2 assay also revealed improved membrane permeability over previous compounds.
Collapse
Affiliation(s)
- Maris A. Cinelli
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Huiying Li
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California, Irvine, Irvine, California 92697-3900, United States
| | - Georges Chreifi
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California, Irvine, Irvine, California 92697-3900, United States
| | - Thomas L. Poulos
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California, Irvine, Irvine, California 92697-3900, United States
| | - Richard B. Silverman
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| |
Collapse
|
10
|
Poulos TL, Li H. Nitric oxide synthase and structure-based inhibitor design. Nitric Oxide 2016; 63:68-77. [PMID: 27890696 DOI: 10.1016/j.niox.2016.11.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 11/09/2016] [Accepted: 11/21/2016] [Indexed: 11/24/2022]
Abstract
Once it was discovered that the enzyme nitric oxide synthase (NOS) is responsible for the biosynthesis of NO, NOS became a drug target. Particularly important is the over production of NO by neuronal NOS (nNOS) in various neurodegenerative disorders. After the various NOS isoforms were identified, inhibitor development proceeded rapidly. It soon became evident, however, that isoform selectivity presents a major challenge. All 3 human NOS isoforms, nNOS, eNOS (endothelial NOS), and iNOS (inducible NOS) have nearly identical active site structures thus making selective inhibitor design especially difficult. Of particular importance is the avoidance of inhibiting eNOS owing to its vital role in the cardiovascular system. This review summarizes some of the history of NOS inhibitor development and more recent advances in developing isoform selective inhibitors using primarily structure-based approaches.
Collapse
Affiliation(s)
- Thomas L Poulos
- Departments of Molecular Biology & Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California, Irvine, Irvine, CA 92697-3900, USA.
| | - Huiying Li
- Departments of Molecular Biology & Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California, Irvine, Irvine, CA 92697-3900, USA
| |
Collapse
|
11
|
Cui G, Shan L, Chen Y, Zhou H, Wang Y, Lee SMY. A New Danshensu Derivative Protects Against 6-Hydroxydopamine-Induced NeurotoxicityIn VitroandIn Vivo. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2016; 44:1349-1361. [DOI: 10.1142/s0192415x16500750] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We previously reported a novel danshensu derivative ([Formula: see text])-(3,5,6-Trimethylpyrazinyl) methyl-2-acetoxy-3-(3,4-diacetoxyphenyl) propanoate (ADTM), which conferred cardioprotective and anti-thrombotic effects in vitro and in vivo. Here, we examined the neuroprotective actions of ADTM on 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in PC12 cells 1 in vitro and zebrafish in vivo. Pretreatment with ADTM significantly inhibited 6-OHDA-induced cytotoxicity and production of reactive oxygen species (ROS) in PC12 cells through Akt signaling. Moreover, treatment with ADTM also inhibited expression of inducible nitric oxide synthase (iNOS) and production of intracellular nitric oxide (NO), which are associated with inflammation. In addition, ADTM exhibited significant protection against 6-OHDA-induced loss of tyrosine hydroxylase-positive dopaminergic neurons in a zebrafish model. Taken together, our findings suggest that ADTM is also a potential effective therapeutic agent for neurodegenerative conditions such as Parkinson’s disease (PD) through anti-oxidant cytoprotective and anti-inflammatory actions.
Collapse
Affiliation(s)
- Guozhen Cui
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macao, P.R. China
- Zhuhai Key Laboratory of Basic and Applied Research in Chinese Medicine, Department of Bioengineering, Zhuhai Campus of Zunyi Medical College, Zhuhai, P.R. China
| | - Luchen Shan
- Institute of New Drug Research, College of Pharmacy, Jinan University, Guangzhou, P.R. China
| | - Yang Chen
- Zhuhai Key Laboratory of Basic and Applied Research in Chinese Medicine, Department of Bioengineering, Zhuhai Campus of Zunyi Medical College, Zhuhai, P.R. China
| | - Hefeng Zhou
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macao, P.R. China
| | - Yuqiang Wang
- Institute of New Drug Research, College of Pharmacy, Jinan University, Guangzhou, P.R. China
| | - Simon Ming-Yuen Lee
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macao, P.R. China
| |
Collapse
|
12
|
Brezovsky J, Babkova P, Degtjarik O, Fortova A, Gora A, Iermak I, Rezacova P, Dvorak P, Smatanova IK, Prokop Z, Chaloupkova R, Damborsky J. Engineering a de Novo Transport Tunnel. ACS Catal 2016. [DOI: 10.1021/acscatal.6b02081] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Jan Brezovsky
- Loschmidt
Laboratories, Department of Experimental Biology and Research Centre
for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Petra Babkova
- Loschmidt
Laboratories, Department of Experimental Biology and Research Centre
for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Oksana Degtjarik
- Faculty
of Science, University of South Bohemia in Ceske Budejovice, Branisovska 1760, 37005 Ceske Budejovice, Czech Republic
- Center for Nanobiology and Structural Biology ASCR, Zamek 136, 37333 Nove Hrady, Czech Republic
| | - Andrea Fortova
- Loschmidt
Laboratories, Department of Experimental Biology and Research Centre
for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Artur Gora
- Loschmidt
Laboratories, Department of Experimental Biology and Research Centre
for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Iuliia Iermak
- Faculty
of Science, University of South Bohemia in Ceske Budejovice, Branisovska 1760, 37005 Ceske Budejovice, Czech Republic
- Center for Nanobiology and Structural Biology ASCR, Zamek 136, 37333 Nove Hrady, Czech Republic
| | - Pavlina Rezacova
- Institute of Organic Chemistry and Biochemistry ASCR, v.v.i. Flemingovo nam. 2, 166 10 Prague 6, Czech Republic
- Institute of Molecular Genetics of the ASCR, v.v.i. Videnska 1083, 142 20 Prague 4, Czech Republic
| | - Pavel Dvorak
- Loschmidt
Laboratories, Department of Experimental Biology and Research Centre
for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Ivana Kuta Smatanova
- Faculty
of Science, University of South Bohemia in Ceske Budejovice, Branisovska 1760, 37005 Ceske Budejovice, Czech Republic
- Center for Nanobiology and Structural Biology ASCR, Zamek 136, 37333 Nove Hrady, Czech Republic
| | - Zbynek Prokop
- Loschmidt
Laboratories, Department of Experimental Biology and Research Centre
for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Radka Chaloupkova
- Loschmidt
Laboratories, Department of Experimental Biology and Research Centre
for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Jiri Damborsky
- Loschmidt
Laboratories, Department of Experimental Biology and Research Centre
for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| |
Collapse
|
13
|
Cinelli MA, Li H, Pensa AV, Kang S, Roman LJ, Martásek P, Poulos TL, Silverman RB. Phenyl Ether- and Aniline-Containing 2-Aminoquinolines as Potent and Selective Inhibitors of Neuronal Nitric Oxide Synthase. J Med Chem 2015; 58:8694-712. [PMID: 26469213 DOI: 10.1021/acs.jmedchem.5b01330] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Excess nitric oxide (NO) produced by neuronal nitric oxide synthase (nNOS) is implicated in neurodegenerative disorders. As a result, inhibition of nNOS and reduction of NO levels is desirable therapeutically, but many nNOS inhibitors are poorly bioavailable. Promising members of our previously reported 2-aminoquinoline class of nNOS inhibitors, although orally bioavailable and brain-penetrant, suffer from unfavorable off-target binding to other CNS receptors, and they resemble known promiscuous binders. Rearranged phenyl ether- and aniline-linked 2-aminoquinoline derivatives were therefore designed to (a) disrupt the promiscuous binding pharmacophore and diminish off-target interactions and (b) preserve potency, isoform selectivity, and cell permeability. A series of these compounds was synthesized and tested against purified nNOS, endothelial NOS (eNOS), and inducible NOS (iNOS) enzymes. One compound, 20, displayed high potency, selectivity, and good human nNOS inhibition, and retained some permeability in a Caco-2 assay. Most promisingly, CNS receptor counterscreening revealed that this rearranged scaffold significantly reduces off-target binding.
Collapse
Affiliation(s)
- Maris A Cinelli
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Huiying Li
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California , Irvine, California 92697-3900, United States
| | - Anthony V Pensa
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Soosung Kang
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Linda J Roman
- Department of Biochemistry, University of Texas Health Science Center , San Antonio, Texas 78384-7760, United States
| | - Pavel Martásek
- Department of Biochemistry, University of Texas Health Science Center , San Antonio, Texas 78384-7760, United States.,Department of Pediatrics, First Faculty of Medicine, Charles University , Prague, Czech Republic.,BIOCEV , Prague, Czech Republic
| | - Thomas L Poulos
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California , Irvine, California 92697-3900, United States
| | - Richard B Silverman
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| |
Collapse
|
14
|
Kang S, Li H, Tang W, Martásek P, Roman LJ, Poulos TL, Silverman RB. 2-Aminopyridines with a Truncated Side Chain To Improve Human Neuronal Nitric Oxide Synthase Inhibitory Potency and Selectivity. J Med Chem 2015; 58:5548-60. [PMID: 26120733 PMCID: PMC4514563 DOI: 10.1021/acs.jmedchem.5b00573] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have analyzed a recently obtained crystal structure of human neuronal nitric oxide synthase (nNOS) and then designed and synthesized several 2-aminopyridine derivatives containing a truncated side chain to avoid the hydrophobic pocket that differentiates human and rat nNOS in an attempt to explore alternative binding poses along the substrate access channel of human nNOS. Introduction of an N-methylethane-1,2-diamine side chain and conformational constraints such as benzonitrile and pyridine as the middle aromatic linker were sufficient to increase human and rat nNOS binding affinity and inducible and endothelial NOS selectivity. We found that 14b is a potent inhibitor; the binding modes with human and rat nNOS are unexpected, inducing side chain rotamer changes in Gln478 (rat) at the top of the active site. Compound 19c exhibits Ki values of 24 and 55 nM for rat and human nNOS, respectively, with 153-fold iNOS and 1040-fold eNOS selectivity. 19c has 18% oral bioavailability.
Collapse
Affiliation(s)
- Soosung Kang
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
- New Drug Development Center, DGMIF, 80 Cheombok-ro, Dae-gu, Korea
| | - Huiying Li
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California, Irvine, California 92697-3900, United States
| | - Wei Tang
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Pavel Martásek
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78384-7760, United States
| | - Linda J. Roman
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78384-7760, United States
| | - Thomas L. Poulos
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California, Irvine, California 92697-3900, United States
| | - Richard B. Silverman
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| |
Collapse
|
15
|
Mukherjee P, Li H, Sevrioukova I, Chreifi G, Martásek P, Roman LJ, Poulos TL, Silverman RB. Novel 2,4-disubstituted pyrimidines as potent, selective, and cell-permeable inhibitors of neuronal nitric oxide synthase. J Med Chem 2014; 58:1067-88. [PMID: 25489882 PMCID: PMC4329833 DOI: 10.1021/jm501719e] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Selective inhibition of neuronal nitric oxide synthase (nNOS) is an important therapeutic approach to target neurodegenerative disorders. However, the majority of the nNOS inhibitors developed are arginine mimetics and, therefore, suffer from poor bioavailability. We designed a novel strategy to combine a more pharmacokinetically favorable 2-imidazolylpyrimidine head with promising structural components from previous inhibitors. In conjunction with extensive structure-activity studies, several highly potent and selective inhibitors of nNOS were discovered. X-ray crystallographic analysis reveals that these type II inhibitors utilize the same hydrophobic pocket to gain strong inhibitory potency (13), as well as high isoform selectivity. Interestingly, select compounds from this series (9) showed good permeability and low efflux in a Caco-2 assay, suggesting potential oral bioavailability, and exhibited minimal off-target binding to 50 central nervous system receptors. Furthermore, even with heme-coordinating groups in the molecule, modifying other pharmacophoric fragments minimized undesirable inhibition of cytochrome P450s from human liver microsomes.
Collapse
Affiliation(s)
- Paramita Mukherjee
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208-3113, United States
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Inhibition of i-NOS but not n-NOS protects rat primary cell cultures against MPP+-induced neuronal toxicity. J Neural Transm (Vienna) 2014; 122:779-88. [DOI: 10.1007/s00702-014-1334-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 11/05/2014] [Indexed: 11/26/2022]
|
17
|
Mukherjee P, Cinelli MA, Kang S, Silverman RB. Development of nitric oxide synthase inhibitors for neurodegeneration and neuropathic pain. Chem Soc Rev 2014; 43:6814-38. [PMID: 24549364 PMCID: PMC4138306 DOI: 10.1039/c3cs60467e] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Nitric oxide (NO) is an important signaling molecule in the human body, playing a crucial role in cell and neuronal communication, regulation of blood pressure, and in immune activation. However, overproduction of NO by the neuronal isoform of nitric oxide synthase (nNOS) is one of the fundamental causes underlying neurodegenerative disorders and neuropathic pain. Therefore, developing small molecules for selective inhibition of nNOS over related isoforms (eNOS and iNOS) is therapeutically desirable. The aims of this review focus on the regulation and dysregulation of NO signaling, the role of NO in neurodegeneration and pain, the structure and mechanism of nNOS, and the use of this information to design selective inhibitors of this enzyme. Structure-based drug design, the bioavailability and pharmacokinetics of these inhibitors, and extensive target validation through animal studies are addressed.
Collapse
Affiliation(s)
- Paramita Mukherjee
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA.
| | | | | | | |
Collapse
|
18
|
Huang H, Silverman RB. Recent advances toward improving the bioavailability of neuronal nitric oxide synthase inhibitors. Curr Top Med Chem 2014; 13:803-12. [PMID: 23578024 DOI: 10.2174/1568026611313070003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 11/01/2013] [Accepted: 11/01/2013] [Indexed: 12/20/2022]
Abstract
Overproduction of nitric oxide by neuronal nitric oxide synthase (nNOS) has been highly correlated with numerous neurodegenerative diseases and stroke. Given its role in human diseases, nNOS is an important target for therapy that deserves further attention. During the last decade, a large number of organic scaffolds have been investigated to develop selective nNOS inhibitors, resulting in two principal classes of compounds, 2-aminopyridines and thiophene-2- carboximidamides. The former compounds were investigated in detail by our group, exhibiting great potency and excellent selectivity; however, they suffer from poor bioavailability, which hampers their therapeutic potential. Here we present a review of various strategies adopted by our group to improve the bioavailability of 2-aminopyridine derivatives and describe recent advances in thiophene-2-carboximidamide based nNOS-selective inhibitors, which exhibit promising pharmacological profiles.
Collapse
Affiliation(s)
- He Huang
- Department of Chemistry, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA
| | | |
Collapse
|
19
|
Cinelli MA, Li H, Chreifi G, Martásek P, Roman LJ, Poulos TL, Silverman RB. Simplified 2-aminoquinoline-based scaffold for potent and selective neuronal nitric oxide synthase inhibition. J Med Chem 2014; 57:1513-30. [PMID: 24472039 PMCID: PMC3954451 DOI: 10.1021/jm401838x] [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: 02/03/2023]
Abstract
![]()
Since high levels of nitric oxide
(NO) are implicated in neurodegenerative
disorders, inhibition of the neuronal isoform of nitric oxide synthase
(nNOS) and reduction of NO levels are therapeutically desirable. Nonetheless,
many nNOS inhibitors mimic l-arginine and are poorly bioavailable.
2-Aminoquinoline-based scaffolds were designed with the hope that
they could (a) mimic aminopyridines as potent, isoform-selective arginine
isosteres and (b) possess chemical properties more conducive to oral
bioavailability and CNS penetration. A series of these compounds was
synthesized and assayed against purified nNOS enzymes, endothelial
NOS (eNOS), and inducible NOS (iNOS). Several compounds built on a
7-substituted 2-aminoquinoline core are potent and isoform-selective;
X-ray crystallography indicates that aminoquinolines exert inhibitory
effects by mimicking substrate interactions with the conserved active
site glutamate residue. The most potent and selective compounds, 7 and 15, were tested in a Caco-2 assay and showed
good permeability and low efflux, suggesting high potential for oral
bioavailability.
Collapse
Affiliation(s)
- Maris A Cinelli
- Departments of Chemistry and Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | | | | | | | | | | | | |
Collapse
|
20
|
Feng C, Chen L, Li W, Elmore BO, Fan W, Sun X. Dissecting regulation mechanism of the FMN to heme interdomain electron transfer in nitric oxide synthases. J Inorg Biochem 2013; 130:130-40. [PMID: 24084585 DOI: 10.1016/j.jinorgbio.2013.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 08/12/2013] [Accepted: 09/05/2013] [Indexed: 11/25/2022]
Abstract
Nitric oxide synthase (NOS), a flavo-hemoprotein, is responsible for biosynthesis of nitric oxide (NO) in mammals. Three NOS isoforms, iNOS, eNOS and nNOS (inducible, endothelial, and neuronal NOS), achieve their biological functions by tight control of interdomain electron transfer (IET) process through interdomain interactions. In particular, the FMN-heme IET is essential in coupling electron transfer in the reductase domain with NO synthesis in the heme domain by delivery of electrons required for O2 activation at the catalytic heme site. Emerging evidence indicates that calmodulin (CaM) activates NO synthesis in eNOS and nNOS by a conformational change of the FMN domain from its shielded electron-accepting (input) state to a new electron-donating (output) state, and that CaM is also required for proper alignment of the FMN and heme domains in the three NOS isoforms. In the absence of a structure of full-length NOS, an integrated approach of spectroscopic, rapid kinetic and mutagenesis methods is required to unravel regulation mechanism of the FMN-heme IET process. This is to investigate the roles of the FMN domain motions and the docking between the primary functional FMN and heme domains in regulating NOS activity. The recent developments in this area that are driven by the combined approach are the focuses of this review. A better understanding of the roles of interdomain FMN/heme interactions and CaM binding may serve as a basis for the rational design of new selective modulators of the NOS enzymes.
Collapse
Affiliation(s)
- Changjian Feng
- Department of Pharmaceutical Sciences, University of New Mexico, Albuquerque, NM 87131, USA.
| | | | | | | | | | | |
Collapse
|
21
|
Cui W, Zhang Z, Li W, Hu S, Mak S, Zhang H, Han R, Yuan S, Li S, Sa F, Xu D, Lin Z, Zuo Z, Rong J, Ma EDL, Choi TC, Lee SM, Han Y. The anti-cancer agent SU4312 unexpectedly protects against MPP(+) -induced neurotoxicity via selective and direct inhibition of neuronal NOS. Br J Pharmacol 2013; 168:1201-14. [PMID: 23062100 DOI: 10.1111/bph.12004] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 09/05/2012] [Accepted: 09/18/2012] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE SU4312, a potent and selective inhibitor of VEGF receptor-2 (VEGFR-2), has been designed to treat cancer. Recent studies have suggested that SU4312 can also be useful in treating neurodegenerative disorders. In this study, we assessed neuroprotection by SU4312 against 1-methyl-4-phenylpyridinium ion (MPP(+) )-induced neurotoxicity and further explored the underlying mechanisms. EXPERIMENTAL APPROACH MPP(+) -treated neurons and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated zebrafish were used to study neuroprotection by SU4312. NOS activity was assayed in vitro to examine direct interactions between SU4312 and NOS isoforms. KEY RESULTS SU4312 unexpectedly prevented MPP(+) -induced neuronal apoptosis in vitro and decreased MPTP-induced loss of dopaminergic neurons, reduced expression of mRNA for tyrosine hydroxylase and impaired swimming behaviour in zebrafish. In contrast, PTK787/ZK222584, a well-studied VEGFR-2 inhibitor, failed to prevent neurotoxicity, suggesting that the neuroprotective actions of SU4312 were independent of its anti-angiogenic action. Furthermore, SU4312 exhibited non-competitive inhibition of purified neuronal NOS (nNOS) with an IC(50) value of 19.0 μM but showed little or no effects on inducible and endothelial NOS. Molecular docking simulations suggested an interaction between SU4312 and the haem group within the active centre of nNOS. CONCLUSIONS AND IMPLICATION SU4312 exhibited neuroprotection against MPP(+) at least partly via selective and direct inhibition of nNOS. Because SU4312 could reach the brain in rats, our study also offered a support for further development of SU4312 to treat neurodegenerative disorders, particularly those associated with NO-mediated neurotoxicity.
Collapse
Affiliation(s)
- Wei Cui
- Department of Applied Biology and Chemical Technology, Institute of Modern Medicine, The Hong Kong Polytechnic University, Hong Kong, China
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Nagpal L, Haque MM, Saha A, Mukherjee N, Ghosh A, Ranu BC, Stuehr DJ, Panda K. Mechanism of inducible nitric-oxide synthase dimerization inhibition by novel pyrimidine imidazoles. J Biol Chem 2013; 288:19685-97. [PMID: 23696643 PMCID: PMC3707674 DOI: 10.1074/jbc.m112.446542] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 05/13/2013] [Indexed: 01/19/2023] Open
Abstract
Overproduction of nitric oxide (NO) by inducible nitric-oxide synthase (iNOS) has been etiologically linked to several inflammatory, immunological, and neurodegenerative diseases. As dimerization of NOS is required for its activity, several dimerization inhibitors, including pyrimidine imidazoles, are being evaluated for therapeutic inhibition of iNOS. However, the precise mechanism of their action is still unclear. Here, we examined the mechanism of iNOS inhibition by a pyrimidine imidazole core compound and its derivative (PID), having low cellular toxicity and high affinity for iNOS, using rapid stopped-flow kinetic, gel filtration, and spectrophotometric analysis. PID bound to iNOS heme to generate an irreversible PID-iNOS monomer complex that could not be converted to active dimers by tetrahydrobiopterin (H4B) and l-arginine (Arg). We utilized the iNOS oxygenase domain (iNOSoxy) and two monomeric mutants whose dimerization could be induced (K82AiNOSoxy) or not induced (D92AiNOSoxy) with H4B to elucidate the kinetics of PID binding to the iNOS monomer and dimer. We observed that the apparent PID affinity for the monomer was 11 times higher than the dimer. PID binding rate was also sensitive to H4B and Arg site occupancy. PID could also interact with nascent iNOS monomers in iNOS-synthesizing RAW cells, to prevent their post-translational dimerization, and it also caused irreversible monomerization of active iNOS dimers thereby accomplishing complete physiological inhibition of iNOS. Thus, our study establishes PID as a versatile iNOS inhibitor and therefore a potential in vivo tool for examining the causal role of iNOS in diseases associated with its overexpression as well as therapeutic control of such diseases.
Collapse
Affiliation(s)
- Latika Nagpal
- From the Department of Biotechnology and Guha Center for Genetic Engineering and Biotechnology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700019, India
| | - Mohammad M. Haque
- the Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, and
| | - Amit Saha
- the Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Nirmalya Mukherjee
- the Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Arnab Ghosh
- the Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, and
| | - Brindaban C. Ranu
- the Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Dennis J. Stuehr
- the Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, and
| | - Koustubh Panda
- From the Department of Biotechnology and Guha Center for Genetic Engineering and Biotechnology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700019, India
| |
Collapse
|
23
|
Trippier PC, Labby KJ, Hawker DD, Mataka JJ, Silverman RB. Target- and mechanism-based therapeutics for neurodegenerative diseases: strength in numbers. J Med Chem 2013; 56:3121-47. [PMID: 23458846 PMCID: PMC3637880 DOI: 10.1021/jm3015926] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The development of new therapeutics for the treatment of neurodegenerative pathophysiologies currently stands at a crossroads. This presents an opportunity to transition future drug discovery efforts to target disease modification, an area in which much still remains unknown. In this Perspective we examine recent progress in the areas of neurodegenerative drug discovery, focusing on some of the most common targets and mechanisms: N-methyl-d-aspartic acid (NMDA) receptors, voltage gated calcium channels (VGCCs), neuronal nitric oxide synthase (nNOS), oxidative stress from reactive oxygen species, and protein aggregation. These represent the key players identified in neurodegeneration and are part of a complex, intertwined signaling cascade. The synergistic delivery of two or more compounds directed against these targets, along with the design of small molecules with multiple modes of action, should be explored in pursuit of more effective clinical treatments for neurodegenerative diseases.
Collapse
Affiliation(s)
- Paul C. Trippier
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Kristin Jansen Labby
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Dustin D. Hawker
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Jan J. Mataka
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Richard B. Silverman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA
- Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL, USA
| |
Collapse
|
24
|
Feng C. Mechanism of Nitric Oxide Synthase Regulation: Electron Transfer and Interdomain Interactions. Coord Chem Rev 2012; 256:393-411. [PMID: 22523434 PMCID: PMC3328867 DOI: 10.1016/j.ccr.2011.10.011] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Nitric oxide synthase (NOS), a flavo-hemoprotein, tightly regulates nitric oxide (NO) synthesis and thereby its dual biological activities as a key signaling molecule for vasodilatation and neurotransmission at low concentrations, and also as a defensive cytotoxin at higher concentrations. Three NOS isoforms, iNOS, eNOS and nNOS (inducible, endothelial, and neuronal NOS), achieve their key biological functions by tight regulation of interdomain electron transfer (IET) process via interdomain interactions. In particular, the FMN-heme IET is essential in coupling electron transfer in the reductase domain with NO synthesis in the heme domain by delivery of electrons required for O(2) activation at the catalytic heme site. Compelling evidence indicates that calmodulin (CaM) activates NO synthesis in eNOS and nNOS through a conformational change of the FMN domain from its shielded electron-accepting (input) state to a new electron-donating (output) state, and that CaM is also required for proper alignment of the domains. Another exciting recent development in NOS enzymology is the discovery of importance of the the FMN domain motions in modulating reactivity and structure of the catalytic heme active site (in addition to the primary role of controlling the IET processes). In the absence of a structure of full-length NOS, an integrated approach of spectroscopic (e.g. pulsed EPR, MCD, resonance Raman), rapid kinetics (laser flash photolysis and stopped flow) and mutagenesis methods is critical to unravel the molecular details of the interdomain FMN/heme interactions. This is to investigate the roles of dynamic conformational changes of the FMN domain and the docking between the primary functional FMN and heme domains in regulating NOS activity. The recent developments in understanding of mechanisms of the NOS regulation that are driven by the combined approach are the focuses of this review. An improved understanding of the role of interdomain FMN/heme interaction and CaM binding may serve as the basis for the design of new selective inhibitors of NOS isoforms.
Collapse
Affiliation(s)
- Changjian Feng
- Department of Pharmaceutical Sciences, University of New Mexico, Albuquerque, NM 87131 (USA) , Tel: 505-925-4326
| |
Collapse
|
25
|
Maddaford SP. A medicinal chemistry perspective on structure-based drug design and development. Methods Mol Biol 2012; 841:351-381. [PMID: 22222460 DOI: 10.1007/978-1-61779-520-6_15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The application of X-ray crystallography and molecular modeling can provide valuable insight into the optimization of the molecular interactions of a drug-protein complex to achieve potency and selectivity of a drug candidate. For the successful application of SBDD in a drug development program, the impact of these structural modifications required to improve potency and selectivity must be considered in the context of balancing of a multitude of drug properties and other considerations that include solubility, bioavailability, metabolism, distribution, toxicology, chemical stability, and intellectual property space. The utility of structure-based design from the medicinal chemist's perspective is described in this chapter.
Collapse
|
26
|
Feng C, Fan W, Ghosh DK, Tollin G. Role of an isoform-specific substrate access channel residue in CO ligand accessibilities of neuronal and inducible nitric oxide synthase isoforms. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1814:405-8. [PMID: 21146639 DOI: 10.1016/j.bbapap.2010.11.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 11/22/2010] [Accepted: 11/24/2010] [Indexed: 10/18/2022]
Abstract
The rates of the bimolecular CO rebinding to the oxygenase domains of inducible and neuronal NOS proteins (iNOSoxy and nNOSoxy, respectively) after photolytic dissociation have been determined by laser flash photolysis. The following mutants at the isoform-specific sites (murine iNOSoxy N115L and rat nNOSoxy L337N, L337F) have been constructed to investigate role of the residues in the CO ligand accessibilities of the NOS isoforms. These residues are in the NOS distal substrate access channel. The effect of the (6R)-5,6,7,8-tetrahydrobiopterin (H(4)B) cofactor and l-arginine (Arg) substrate on the rates of CO rebinding have also been assessed. Addition of l-Arg to the iNOSoxy N115L mutant results in much faster CO rebinding rates, compared to the wild type. The results indicate that modifications to the iNOS channel in which the hydrophilic residue N115 is replaced by leucine (to resemble its nNOS cognate) open the channel somewhat, thereby improving access to the axial heme ligand binding position. On the other hand, introduction of a hydrophilic residue (L337N) or a bulky rigid aromatic residue (L337F) in the nNOS isoform does not significantly affect the kinetics profile, suggesting that the geometry of the substrate access pocket is not greatly altered. The bimolecular CO rebinding rate data indicate that the opening of the substrate access channel in the iNOS N115L mutant may be due to more widespread structural alterations induced by the mutation.
Collapse
Affiliation(s)
- Changjian Feng
- College of Pharmacy, University of New Mexico, Albuquerque, NM 87131, USA.
| | | | | | | |
Collapse
|
27
|
Xue F, Li H, Fang J, Roman LJ, Martásek P, Poulos TL, Silverman RB. Peripheral but crucial: a hydrophobic pocket (Tyr(706), Leu(337), and Met(336)) for potent and selective inhibition of neuronal nitric oxide synthase. Bioorg Med Chem Lett 2010; 20:6258-61. [PMID: 20833542 PMCID: PMC2952696 DOI: 10.1016/j.bmcl.2010.08.096] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 08/17/2010] [Accepted: 08/18/2010] [Indexed: 10/19/2022]
Abstract
Selective inhibition of the neuronal isoform of nitric oxide synthase (nNOS) over endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) has become a promising strategy for the discovery of new therapeutic agents for neurodegenerative diseases. However, because of the high sequence homology of different isozymes in the substrate binding pocket, developing inhibitors with both potency and excellent isoform selectivity remains a challenging problem. Herein, we report the evaluation of a recently discovered peripheral hydrophobic pocket (Tyr(706), Leu(337), and Met(336)) that opens up upon inhibitor binding and its potential in designing potent and selective nNOS inhibitors using three compounds, 2a, 2b, and 3. Crystal structure results show that inhibitors 2a and 3 adopted the same binding mode as lead compound 1. We also found that hydrophobic interactions between the 4-methyl group of the aminopyridine ring of these compounds with the side chain of Met(336), as well as the π-π stacking interaction between the pyridinyl motif and the side chain of Tyr(706) are important for the high potency and selectivity of these nNOS inhibitors.
Collapse
Affiliation(s)
- Fengtian Xue
- Department of Chemistry, Department of Biochemistry, Molecular Biology, and Cell Biology, Center for Molecular Innovation and Drug Discovery, and Chemistry of Life Processes Institute, Northwestern University, 2145 Sheridan Road, Evanston, Illinois, 60208-3113, , 847-491-5653
| | - Huiying Li
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Chemistry, and Chemistry, University of California, Irvine, California 92697-3900, , 949-824-7020
| | - Jianguo Fang
- Department of Chemistry, Department of Biochemistry, Molecular Biology, and Cell Biology, Center for Molecular Innovation and Drug Discovery, and Chemistry of Life Processes Institute, Northwestern University, 2145 Sheridan Road, Evanston, Illinois, 60208-3113, , 847-491-5653
| | - Linda J. Roman
- Department of Biochemistry, The University of Texas Health Science Center, San Antonio, Texas 78384-7760
| | - Pavel Martásek
- Department of Biochemistry, The University of Texas Health Science Center, San Antonio, Texas 78384-7760
| | - Thomas L. Poulos
- Departments of Molecular Biology and Biochemistry, Pharmaceutical Chemistry, and Chemistry, University of California, Irvine, California 92697-3900, , 949-824-7020
| | - Richard B. Silverman
- Department of Chemistry, Department of Biochemistry, Molecular Biology, and Cell Biology, Center for Molecular Innovation and Drug Discovery, and Chemistry of Life Processes Institute, Northwestern University, 2145 Sheridan Road, Evanston, Illinois, 60208-3113, , 847-491-5653
| |
Collapse
|
28
|
Salerno JC, Ghosh DK. Space, time and nitric oxide - neuronal nitric oxide synthase generates signal pulses. FEBS J 2009; 276:6677-88. [DOI: 10.1111/j.1742-4658.2009.07382.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
29
|
Fang J, Ji H, Lawton GR, Xue F, Roman LJ, Silverman RB. L337H mutant of rat neuronal nitric oxide synthase resembles human neuronal nitric oxide synthase toward inhibitors. J Med Chem 2009; 52:4533-7. [PMID: 19537690 DOI: 10.1021/jm900380j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A common dichotomy exists in inhibitor design: should the compounds be designed to block the enzymes of animals in the preclinical studies or to inhibit the human enzyme? We report that a single mutation of Leu-337 in rat neuronal nitric oxide synthase (nNOS) to His makes the enzyme resemble human nNOS more than rat nNOS. We expect that the approach used in this study can unite the dichotomy and speed up the process of inhibitor design and development.
Collapse
Affiliation(s)
- Jianguo Fang
- Department of Chemistry, Center for Molecular Innovation and Drug Discovery, Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208-3113, USA
| | | | | | | | | | | |
Collapse
|
30
|
Pavlova M, Klvana M, Prokop Z, Chaloupkova R, Banas P, Otyepka M, Wade RC, Tsuda M, Nagata Y, Damborsky J. Redesigning dehalogenase access tunnels as a strategy for degrading an anthropogenic substrate. Nat Chem Biol 2009; 5:727-33. [PMID: 19701186 DOI: 10.1038/nchembio.205] [Citation(s) in RCA: 212] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Accepted: 05/28/2009] [Indexed: 01/17/2023]
Abstract
Engineering enzymes to degrade anthropogenic compounds efficiently is challenging. We obtained Rhodococcus rhodochrous haloalkane dehalogenase mutants with up to 32-fold higher activity than wild type toward the toxic, recalcitrant anthropogenic compound 1,2,3-trichloropropane (TCP) using a new strategy. We identified key residues in access tunnels connecting the buried active site with bulk solvent by rational design and randomized them by directed evolution. The most active mutant has large aromatic residues at two out of three randomized positions and two positions modified by site-directed mutagenesis. These changes apparently enhance activity with TCP by decreasing accessibility of the active site for water molecules, thereby promoting activated complex formation. Kinetic analyses confirmed that the mutations improved carbon-halogen bond cleavage and shifted the rate-limiting step to the release of products. Engineering access tunnels by combining computer-assisted protein design with directed evolution may be a valuable strategy for refining catalytic properties of enzymes with buried active sites.
Collapse
Affiliation(s)
- Martina Pavlova
- Loschmidt Laboratories, Institute of Experimental Biology and National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Fang J, Silverman RB. A cellular model for screening neuronal nitric oxide synthase inhibitors. Anal Biochem 2009; 390:74-8. [PMID: 19362065 PMCID: PMC2688442 DOI: 10.1016/j.ab.2009.04.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 03/27/2009] [Accepted: 04/03/2009] [Indexed: 11/26/2022]
Abstract
Nitric oxide synthase (NOS) inhibitors are potential drug candidates because it has been well demonstrated that excessive production of nitric oxide critically contributes to a range of diseases. Most inhibitors have been screened in vitro using recombinant enzymes, leading to the discovery of a variety of potent compounds. To make inhibition studies more physiologically relevant and bridge the gap between the in vitro assay and in vivo studies, we report here a cellular model for screening NOS inhibitors. Stable transformants were generated by overexpressing rat neuronal NOS in HEK 293T cells. The enzyme was activated by introducing calcium ions into cells, and its activity was assayed by determining the amount of nitrite that was formed in culture medium using the Griess reagent. We tested a few NOS inhibitors with this assay and found that the method is sensitive, versatile, and easy to use. The cell-based assay provides more information than in vitro assays regarding the bioavailability of NOS inhibitors, and it is suitable for high-throughput screening.
Collapse
Affiliation(s)
- Jianguo Fang
- Department of Chemistry, Northwestern University, Evanston, IL 60208-3113, USA
| | | |
Collapse
|
32
|
Pavelka A, Chovancova E, Damborsky J. HotSpot Wizard: a web server for identification of hot spots in protein engineering. Nucleic Acids Res 2009; 37:W376-83. [PMID: 19465397 PMCID: PMC2703904 DOI: 10.1093/nar/gkp410] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
HotSpot Wizard is a web server for automatic identification of 'hot spots' for engineering of substrate specificity, activity or enantioselectivity of enzymes and for annotation of protein structures. The web server implements the protein engineering protocol, which targets evolutionarily variable amino acid positions located in the active site or lining the access tunnels. The 'hot spots' for mutagenesis are selected through the integration of structural, functional and evolutionary information obtained from: (i) the databases RCSB PDB, UniProt, PDBSWS, Catalytic Site Atlas and nr NCBI and (ii) the tools CASTp, CAVER, BLAST, CD-HIT, MUSCLE and Rate4Site. The protein structure and e-mail address are the only obligatory inputs for the calculation. In the output, HotSpot Wizard lists annotated residues ordered by estimated mutability. The results of the analysis are mapped on the enzyme structure and visualized in the web browser using Jmol. The HotSpot Wizard server should be useful for protein engineers interested in exploring the structure of their favourite protein and for the design of mutations in site-directed mutagenesis and focused directed evolution experiments. HotSpot Wizard is available at http://loschmidt.chemi.muni.cz/hotspotwizard/.
Collapse
Affiliation(s)
- Antonin Pavelka
- Loschmidt Laboratories, Institute of Experimental Biology and National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5/A4, 625 00 Brno, Czech Republic
| | | | | |
Collapse
|
33
|
Design of Benzene-1,2-diamines as selective inducible nitric oxide synthase inhibitors: a combined de novo design and docking analysis. J Mol Model 2008; 14:215-24. [DOI: 10.1007/s00894-007-0263-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2007] [Accepted: 12/04/2007] [Indexed: 10/22/2022]
|
34
|
Levesque MC, Ghosh DK, Beasley BE, Chen Y, Volkheimer AD, O'Loughlin CW, Gockerman JP, Moore JO, Weinberg JB. CLL cell apoptosis induced by nitric oxide synthase inhibitors: correlation with lipid solubility and NOS1 dissociation constant. Leuk Res 2008; 32:1061-70. [PMID: 18180035 DOI: 10.1016/j.leukres.2007.11.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Revised: 09/10/2007] [Accepted: 11/15/2007] [Indexed: 11/29/2022]
Abstract
Nitric oxide synthase (NOS) inhibitors induce chronic lymphocytic leukemia (CLL) cell apoptosis and have potential as CLL therapeutics. We determined the half-maximal concentration (ED(50)) of 22 NOS inhibitors that induced CLL cell death in vitro. There was a direct correlation of the NOS1 (but not NOS2) dissociation constant (K(d)) and the hydrophobicity partitioning coefficient of each NOS inhibitor and its ED(50). NOS inhibitors that bound tightly to CLL cell NOS1 and were hydrophobic potently induced CLL cell death. CLL cell RNA and protein analyses confirmed CLL cell NOS1 expression. Our studies permit the rational selection of NOS inhibitors for testing as CLL therapeutics.
Collapse
Affiliation(s)
- Marc C Levesque
- Department of Medicine, Division of Rheumatology and Clinical Immunology, Duke University and Durham VA Medical Centers, Durham, NC 27710, United States.
| | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Le Bourdonnec B, Leister LK, Ajello CA, Cassel JA, Seida PR, O'Hare H, Gu M, Chu GH, Tuthill PA, DeHaven RN, Dolle RE. Discovery of a series of aminopiperidines as novel iNOS inhibitors. Bioorg Med Chem Lett 2007; 18:336-43. [PMID: 18024030 DOI: 10.1016/j.bmcl.2007.10.073] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 10/19/2007] [Accepted: 10/20/2007] [Indexed: 11/24/2022]
Abstract
Nitric oxide (NO), a mediator of various physiological and pathophysiological processes, is synthesized by three isozymes of nitric oxide synthase (NOS). Potential candidate clinical drugs should be devoid of inhibitory activity against endothelial NOS (eNOS), since eNOS plays an important role in maintaining normal blood pressure and flow. A new series of aminopiperidines as potent inhibitors of iNOS were identified from a HTS lead. From this study, we identified compound 33 as a potent iNOS inhibitor, with >25-fold selectivity over eNOS and 16-fold selectivity over nNOS.
Collapse
Affiliation(s)
- Bertrand Le Bourdonnec
- Department of Chemistry, Adolor Corporation, 700 Pennsylvania Drive, Exton, PA 19341, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Martin NI, Woodward JJ, Winter MB, Beeson WT, Marletta MA. Design and Synthesis of C5 Methylated l-Arginine Analogues as Active Site Probes for Nitric Oxide Synthase. J Am Chem Soc 2007; 129:12563-70. [PMID: 17892291 DOI: 10.1021/ja0746159] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The role of nitric oxide (NO) as a biological signaling molecule is well established. NO is produced by the nitric oxide synthases (NOSs, EC 1.14.13.39), a class of heme proteins capable of converting l-arginine to NO and l-citrulline. Despite the large body of knowledge associated with the NOSs, mechanistic details relating to the unique oxidative chemistry performed by these enzymes remain to be fully elucidated. Furthermore, a number of disease states are associated with either the over- or underproduction of NO, making the NOS pathway an attractive target for the development of therapeutics. For these reasons, molecular tools capable of providing mechanistic insights into the production of NO and/or the inhibition of the NOSs remain of interest. We report here the stereospecific synthesis and testing of a number of new l-arginine analogues bearing a minimal substitution, methylation at position 5 of the amino acid side chain (such analogues have not been previously reported). The synthetic approach employed a modified photolysis procedure whereby irradiation of the appropriate diacylperoxide precursors at 254 nm gave access to the required unnatural amino acids in good yields. A heme domain construct of the inducible NOS isoform (iNOSheme) was used to assess the binding of each compound to the enzyme active site. The compounds were also investigated as either inhibitors of, or alternate substrates for, the inducible NOS isoform. The results obtained provide new insight into the steric and stereochemical tolerance of the enzyme active site. These findings also further support the role of a conserved active site water molecule previously proposed to be necessary for NOS catalysis.
Collapse
Affiliation(s)
- Nathaniel I Martin
- Departments of Chemistry, Molecular and Cellular Biology, and Division of Physical Sciences, Lawrence Berkeley National Laboratory, University of California, Berkeley, Berkeley, California 94720-1460, USA
| | | | | | | | | |
Collapse
|
37
|
Aparna V, Desiraju GR, Gopalakrishnan B. Insights into ligand selectivity in nitric oxide synthase isoforms: A molecular dynamics study. J Mol Graph Model 2007; 26:457-70. [PMID: 17350298 DOI: 10.1016/j.jmgm.2007.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Revised: 02/12/2007] [Accepted: 02/12/2007] [Indexed: 11/20/2022]
Abstract
Molecular dynamics (MD) simulations were carried out for inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) isoforms complexed with substrate (L-arginine) and the iNOS specific inhibitor GW 273629, 2 for a time period of 1.2ns. The simulations were compared both within and across the isoforms. iNOS specificity of inhibitor 2 is attributed to water mediated interactions and cooperative hydrogen bond networks. Juxtaposition of the carboxylic and ammonium groups in the substrate and inhibitor serve as a modulating key in binding to the isoforms. Based on these investigations, molecules 3 and 4 were rationally designed to attain specificity among the isoforms. The capability of the designed ligands was theoretically tested through MD simulations to envisage binding patterns with both isoforms. A detailed analysis of the molecular recognition pattern shows molecule 4 to be more selective to iNOS when compared to eNOS.
Collapse
Affiliation(s)
- V Aparna
- School of Chemistry, University of Hyderabad, Hyderabad 500046, India
| | | | | |
Collapse
|
38
|
Seo J, Igarashi J, Li H, Martásek P, Roman LJ, Poulos TL, Silverman RB. Structure-based design and synthesis of N(omega)-nitro-L-arginine-containing peptidomimetics as selective inhibitors of neuronal nitric oxide synthase. Displacement of the heme structural water. J Med Chem 2007; 50:2089-99. [PMID: 17425297 PMCID: PMC2562355 DOI: 10.1021/jm061305c] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The neuronal isoform of nitric oxide synthase (nNOS), the enzyme responsible for the production of nitric oxide in the central nervous system, represents an attractive target for the treatment of various neurodegenerative disorders. X-ray crystal structures of complexes of nNOS with two nNOS-selective inhibitors, (4S)-N-{4-amino-5-[(2-aminoethylamino]pentyl}-N'-nitroguanidine (1) and 4-N-(Nomega-nitro-l-argininyl)-trans-4-amino-l-proline amide (2), led to the discovery of a conserved structural water molecule that was hydrogen bonded between the two heme propionates and the inhibitors (Figure 2). On the basis of this observation, we hypothesized that by attaching a hydrogen bond donor group to the amide nitrogen of 2 or to the secondary amine nitrogen of 1, the inhibitor molecules could displace the structural water molecule and obtain a direct interaction with the heme cofactor. To test this hypothesis, peptidomimetic analogues 3-5, which have either an N-hydroxyl (3 and 5) or N-amino (4) donor group, were designed and synthesized. X-ray crystal structures of nNOS with inhibitors 3 and 5 bound verified that the N-hydroxyl group had, indeed, displaced the structural water molecule and provided a direct interaction with the heme propionate moiety (Figures 5 and 6). Surprisingly, in vitro activity assay results indicated that the addition of a hydroxyl group (3) only increased the potency slightly against the neuronal isoform over the parent compound (1). Rationalizations for the small increase in potency are consistent with other changes in the crystal structures.
Collapse
Affiliation(s)
- Jiwon Seo
- Department of Chemistry, Department of Biochemistry, Molecular Biology, and Cell Biology, and the Center for Drug Discovery and Chemical Biology, Northwestern University, Evanston, Illinois 60208-3113 USA
| | - Jotato Igarashi
- Departments of Molecular Biology and Biochemistry, Physiology and Biophysics, and Chemistry and Program in Macromolecular Structure, University of California, Irvine, California 92697-3900 USA
| | - Huiying Li
- Departments of Molecular Biology and Biochemistry, Physiology and Biophysics, and Chemistry and Program in Macromolecular Structure, University of California, Irvine, California 92697-3900 USA
| | - Pavel Martásek
- Department of Biochemistry, The University of Texas Health Science Center, San Antonio, Texas 78384-7760 USA
| | - Linda J. Roman
- Department of Biochemistry, The University of Texas Health Science Center, San Antonio, Texas 78384-7760 USA
| | - Thomas L. Poulos
- Departments of Molecular Biology and Biochemistry, Physiology and Biophysics, and Chemistry and Program in Macromolecular Structure, University of California, Irvine, California 92697-3900 USA
| | - Richard B. Silverman
- Department of Chemistry, Department of Biochemistry, Molecular Biology, and Cell Biology, and the Center for Drug Discovery and Chemical Biology, Northwestern University, Evanston, Illinois 60208-3113 USA
| |
Collapse
|
39
|
Feng C, Tollin G, Hazzard JT, Nahm NJ, Guillemette JG, Salerno JC, Ghosh DK. Direct measurement by laser flash photolysis of intraprotein electron transfer in a rat neuronal nitric oxide synthase. J Am Chem Soc 2007; 129:5621-9. [PMID: 17425311 DOI: 10.1021/ja068685b] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Intraprotein interdomain electron transfer (IET) from flavin mononucleotide (FMN) to heme is essential in nitric oxide (NO) synthesis by NO synthase (NOS). Our previous laser flash photolysis studies have provided a direct determination of the kinetics of IET between the FMN and heme domains in truncated oxyFMN constructs of rat neuronal NOS (nNOS) and murine inducible NOS (iNOS), in which only the oxygenase and FMN domains along with the calmodulin (CaM) binding site are present [Feng, C. J.; Tollin, G.; Holliday, M. A.; Thomas, C.; Salerno, J. C.; Enemark, J. H.; Ghosh, D. K. Biochemistry 2006, 45, 6354-6362. Feng, C. J.; Thomas, C.; Holliday, M. A.; Tollin, G.; Salerno, J. C.; Ghosh, D. K.; Enemark, J. H. J. Am. Chem. Soc. 2006, 128, 3808-3811]. Here, we report the kinetics of IET between the FMN and heme domains in a rat nNOS holoenzyme in the presence and absence of added CaM using laser flash photolysis of CO dissociation in comparative studies on partially reduced NOS and a single domain NOS oxygenase construct. The IET rate constant in the presence of CaM is 36 s-1, whereas no IET was observed in the absence of CaM. The kinetics reported here are about an order of magnitude slower than the kinetics in a rat nNOS oxyFMN construct with added CaM (262 s-1). We attribute the slower IET between FMN and heme in the holoenzyme to the additional step of dissociation of the FMN domain from the reductase complex before reassociation with the oxygenase domain to form the electron-transfer competent output state complex. This work provides the first direct measurement of CaM-controlled electron transfer between catalytically significant redox couples of FMN and heme in a nNOS holoenzyme.
Collapse
Affiliation(s)
- Changjian Feng
- College of Pharmacy, University of New Mexico, Albuquerque, New Mexico 87131, USA.
| | | | | | | | | | | | | |
Collapse
|
40
|
Li W, Xue J, Niu C, Fu H, Lam CSC, Luo J, Chan HHN, Xue H, Kan KKW, Lee NTK, Li C, Pang Y, Li M, Tsim KWK, Jiang H, Chen K, Li X, Han Y. Synergistic neuroprotection by bis(7)-tacrine via concurrent blockade of N-methyl-D-aspartate receptors and neuronal nitric-oxide synthase. Mol Pharmacol 2007; 71:1258-67. [PMID: 17299028 DOI: 10.1124/mol.106.029108] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The excessive activation of the N-methyl-D-aspartate receptor (NMDAR)/nitric oxide (NO) pathway has been proposed to be involved in the neuropathology of various neurodegenerative disorders. In this study, NO was found to mediate glutamate-induced excitotoxicity in primary cultured neurons. Compared with the NO synthase (NOS) inhibitor, N(G)-monomethyl-L-arginine (L-NMMA), and the NMDAR antagonist memantine, bis(7)-tacrine was found to be more potent in reducing NO-mediated excitotoxicity and the release of NO caused by glutamate. Moreover, like L-NMMA but not like 5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801) and memantine, bis(7)-tacrine showed greater neuroprotection and inhibition on NO release when neurons were pretreated for a prolonged time between 0 and 24 h and remained quite potent even when neurons were post-treated 1 h after the glutamate challenge. Bis(7)-tacrine was additionally found to be as moderately potent as memantine in competing with [(3)H]MK-801, inhibiting NMDA-evoked currents and reducing glutamate-triggered calcium influx, which eventually reduced neuronal NOS activity. More importantly, at neuroprotective concentrations, bis(7)-tacrine substantially reversed the overactivation of neuronal NOS caused by glutamate without interfering with the basal activity of NOS. Furthermore, in vitro pattern analysis demonstrated that bis(7)-tacrine competitively inhibited both purified neuronal and inducible NOS with IC(50) values at 2.9 and 9.3 microM but not endothelial NOS. This result was further supported by molecular docking simulations that showed hydrophobic interactions between bis(7)-tacrine and three NOS isozymes. Taken together, these results strongly suggest that the substantial neuroprotection against glutamate by bis(7)-tacrine might be mediated synergistically through the moderate blockade of NMDAR and selective inhibition of neuronal NOS.
Collapse
Affiliation(s)
- Wenming Li
- Department of Biochemistry, Hong Kong University of Science and Technology, Hong Kong, China
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Feng C, Thomas C, Holliday MA, Tollin G, Salerno JC, Ghosh DK, Enemark JH. Direct measurement by laser flash photolysis of intramolecular electron transfer in a two-domain construct of murine inducible nitric oxide synthase. J Am Chem Soc 2006; 128:3808-11. [PMID: 16536556 DOI: 10.1021/ja0578606] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Intersubunit intramolecular electron transfer (IET) from FMN to heme is essential in the delivery of electrons required for O2 activation in the heme domain and the subsequent nitric oxide (NO) synthesis by NO synthase (NOS). Previous crystal structures and functional studies primarily concerned an enzyme conformation that serves as the input state for reduction of FMN by electrons from NADPH and FAD in the reductase domain. To favor formation of the output state for the subsequent IET from FMN to heme in the oxygenase domain, a novel truncated two-domain oxyFMN construct murine inducible nitric oxide synthase (iNOS), in which only the FMN and heme domains were present, was designed and expressed. The kinetics of the IET between the FMN and heme domains in this construct was directly determined using laser flash photolysis of CO dissociation in comparative studies on partially reduced oxyFMN and single domain heme oxygenase constructs.
Collapse
Affiliation(s)
- Changjian Feng
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721, USA
| | | | | | | | | | | | | |
Collapse
|
42
|
Ghosh DK, Holliday MA, Thomas C, Weinberg JB, Smith SME, Salerno JC. Nitric-oxide Synthase Output State. J Biol Chem 2006; 281:14173-83. [PMID: 16461329 DOI: 10.1074/jbc.m509937200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian nitric-oxide synthases are large modular enzymes that evolved from independently expressed ancestors. Calmodulin-controlled isoforms are signal generators; calmodulin activates electron transfer from NADPH through three reductase domains to an oxygenase domain. Structures of the reductase unit and its homologs show FMN and FAD in contact but too isolated from the protein surface to permit exit of reducing equivalents. To study states in which FMN/heme electron transfer is feasible, we designed and produced constructs including only oxygenase and FMN binding domains, eliminating strong internal reductase complex interactions. Constructs for all mammalian isoforms were expressed and purified as dimers. All synthesize NO with peroxide as the electron donor at rates comparable with corresponding oxygenase constructs. All bind cofactors nearly stoichiometrically and have native catalytic sites by spectroscopic criteria. Modest differences in electrochemistry versus independently expressed heme and FMN binding domains suggest interdomain interactions. These interactions can be convincingly demonstrated via calmodulin-induced shifts in high spin ferriheme EPR spectra and through mutual broadening of heme and FMNH. radical signals in inducible nitric-oxide synthase constructs. Blue neutral FMN semiquinone can be readily observed; potentials of one electron couple (in inducible nitric-oxide synthase oxygenase FMN, FMN oxidized/semiquinone couple = +70 mV, FMN semiquinone/hydroquinone couple = -180 mV, and heme = -180 mV) indicate that FMN is capable of serving as a one electron heme reductant. The construct will serve as the basis for future studies of the output state for NADPH derived reducing equivalents.
Collapse
Affiliation(s)
- Dipak K Ghosh
- Department of Medicine, Duke University and Veterans Affairs Medical Center, Durham, North Carolina 27705, USA.
| | | | | | | | | | | |
Collapse
|
43
|
Li W, Lee NTK, Fu H, Kan KKW, Pang Y, Li M, Tsim KWK, Li X, Han Y. Neuroprotection via inhibition of nitric oxide synthase by bis(7)-tacrine. Neuroreport 2006; 17:471-4. [PMID: 16543809 DOI: 10.1097/01.wnr.0000209014.09094.72] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Here we report that bis(7)-tacrine, a novel acetylcholinesterase inhibitor, exerts neuroprotective effects by inhibition of nitric oxide synthase. In cortical neurons at 12 days in vitro, bis(7)-tacrine concentration-dependently reduced cell death induced by glutamate, beta-amyloid and L-arginine, but not by nitric sodium nitroprusside. N-monomethyl-L-arginine, a nitric oxide synthase inhibitor, also prevented the former three types but not the last type of the cytotoxicity; however, nitric oxide scavengers blocked all of these insults, indicating that nitric oxide mediated these neuronal injuries. Furthermore, with nitric oxide synthase activity assays, it was found that bis(7)-tacrine not only suppressed the activation of nitric oxide synthase caused by glutamate in cortical neurons, but also directly inhibited the activity of nitric oxide synthase in vitro.
Collapse
Affiliation(s)
- Wenming Li
- Department of Biochemistry, Hong Kong University of Science and Technology, Hong Kong, China
| | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Lefebvre RA, Dick JMC, Guérin S, Malbert CH. Influence of the selective neuronal NO synthase inhibitor ARL 17477 on nitrergic neurotransmission in porcine stomach. Eur J Pharmacol 2005; 525:143-9. [PMID: 16257402 DOI: 10.1016/j.ejphar.2005.09.053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Revised: 09/12/2005] [Accepted: 09/27/2005] [Indexed: 10/25/2022]
Abstract
Selective neuronal NOS (nNOS) inhibitors have been developed for possible application in cerebral ischemia and neurodegenerative disorders. To investigate the degree of interference with peripheral nNOS, the influence of the selective nNOS inhibitor ARL 17477 was studied on electrically induced nitrergic relaxations in pig gastric fundus strips and on gastric fundic compliance in conscious pig. Circular muscle strips of porcine gastric fundus were electrically stimulated (10 s trains at 4 Hz, 0.1 ms and 40 V). ARL 17477 inhibited the electrically induced relaxations in a concentration-dependent way (3x10(-6) M-10(-4) M). The inhibitory effect of ARL 17477 developed more progressively than that of N(G)-nitro-L-arginine methyl ester (L-NAME; 3x10(-4) M). In conscious pigs, instrumented with a fundic cannula, L-NAME (20 mg/kg i.v.) significantly increased mean arterial blood pressure and decreased fundic compliance in the fasted state (71+/-13 ml/mm Hg versus 185+/-37 ml/mm Hg after saline; P<0.05). ARL 17477 (3 mg/kg, i.v.) did not influence blood pressure but influenced gastric fundic volume-pressure curves in a similar way as L-NAME. Plasma concentration analysis of ARL 17477 indicated a half-life of less than 30 min in pig. ARL 17477 thus inhibits the effect of nitrergic neurons in the pig gastric fundus in vitro, leading to inhibited gastric compliance in the conscious pig. The study indicates that selective nNOS inhibitors, applied for cerebral disorders, might also interfere with neuronal nitrergic regulation of gastrointestinal motility.
Collapse
Affiliation(s)
- Romain A Lefebvre
- Heymans Institute of Pharmacology, Faculty of Medicine and Health Sciences, Ghent University, De Pintelaan 185, B-9000 Gent, Belgium.
| | | | | | | |
Collapse
|
45
|
Tseng HY, Wu SH, Huang WH, Wang SF, Yang YN, Mahindroo N, Hsu T, Jiaang WT, Lee SJ. Benzothiazolium compounds: novel classes of inhibitors that suppress the nitric oxide production in RAW264.7 cells stimulated by LPS/IFNgamma. Bioorg Med Chem Lett 2005; 15:2027-32. [PMID: 15808462 DOI: 10.1016/j.bmcl.2005.02.063] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2005] [Revised: 01/31/2005] [Accepted: 02/18/2005] [Indexed: 11/22/2022]
Abstract
A series of benzothiazolium compounds were identified as novel classes of inhibitors of nitric oxide production in a cell culture system. They exhibited approximately 1600 folds potency with IC(50) at approximately 50nM to several microM as compared to IC(50) 88.4microM of l-NMMA, a known inhibitor of nitric oxide synthase. The mechanistic studies suggest that decreased iNOS protein synthesis and mRNA transcription, at least in part, were related to the inhibitory activity of effective benzothiazolium compounds. The correlation of in vivo and in vitro activities using mouse paw edema model was also demonstrated.
Collapse
Affiliation(s)
- Huan-Yi Tseng
- Division of Biotechnology and Pharmaceutical Researches, National Health Research Institutes, 35, Keyan Road, Zhunan Town, Miaoli County, Taiwan, ROC
| | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Arakaki TL, Pezza JA, Cronin MA, Hopkins CE, Zimmer DB, Tolan DR, Allen KN. Structure of human brain fructose 1,6-(bis)phosphate aldolase: linking isozyme structure with function. Protein Sci 2004; 13:3077-84. [PMID: 15537755 PMCID: PMC2287316 DOI: 10.1110/ps.04915904] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Fructose-1,6-(bis)phosphate aldolase is a ubiquitous enzyme that catalyzes the reversible aldol cleavage of fructose-1,6-(bis)phosphate and fructose 1-phosphate to dihydroxyacetone phosphate and either glyceral-dehyde-3-phosphate or glyceraldehyde, respectively. Vertebrate aldolases exist as three isozymes with different tissue distributions and kinetics: aldolase A (muscle and red blood cell), aldolase B (liver, kidney, and small intestine), and aldolase C (brain and neuronal tissue). The structures of human aldolases A and B are known and herein we report the first structure of the human aldolase C, solved by X-ray crystallography at 3.0 A resolution. Structural differences between the isozymes were expected to account for isozyme-specific activity. However, the structures of isozymes A, B, and C are the same in their overall fold and active site structure. The subtle changes observed in active site residues Arg42, Lys146, and Arg303 are insufficient to completely account for the tissue-specific isozymic differences. Consequently, the structural analysis has been extended to the isozyme-specific residues (ISRs), those residues conserved among paralogs. A complete analysis of the ISRs in the context of this structure demonstrates that in several cases an amino acid residue that is conserved among aldolase C orthologs prevents an interaction that occurs in paralogs. In addition, the structure confirms the clustering of ISRs into discrete patches on the surface and reveals the existence in aldolase C of a patch of electronegative residues localized near the C terminus. Together, these structural changes highlight the differences required for the tissue and kinetic specificity among aldolase isozymes.
Collapse
Affiliation(s)
- Tracy L Arakaki
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts 02118-2394, USA
| | | | | | | | | | | | | |
Collapse
|