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Ogbonna EN, Terrell JR, Paul A, Farahat AA, Poon GMK, Boykin DW, Wilson WD. Single GC base pair recognition by a heterocyclic diamidine: structures, affinities, and dynamics. RSC Adv 2024; 14:29675-29682. [PMID: 39297050 PMCID: PMC11408989 DOI: 10.1039/d4ra05957c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2024] [Accepted: 09/04/2024] [Indexed: 09/21/2024] Open
Abstract
The recognition of specific genomic arrangements by rationally designed small molecules is fundamental for the expansion of targeted gene expression. Here, we report the first X-ray crystal structures that demonstrate single G (guanine) recognition by a highly selective diamidine (DB2447) in a mixed DNA sequence. The study presents detailed structural information on the mechanism of single G recognition by D2447 and its various interactions in the DNA minor groove. Molecular dynamics and binding studies were used to evaluate the details of our reported structures. The study provides structural insight and resources necessary for understanding single G selection in genomic sequences.
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Affiliation(s)
- Edwin N Ogbonna
- Department of Chemistry and Centre of Diagnostics and Therapeutics, Georgia State University Atlanta GA 30303-3083 USA +1 404-413-5505 +1 404-413-5503
| | - J Ross Terrell
- Department of Chemistry and Centre of Diagnostics and Therapeutics, Georgia State University Atlanta GA 30303-3083 USA +1 404-413-5505 +1 404-413-5503
| | - Ananya Paul
- Department of Chemistry and Centre of Diagnostics and Therapeutics, Georgia State University Atlanta GA 30303-3083 USA +1 404-413-5505 +1 404-413-5503
| | - Abdelbasset A Farahat
- Department of Chemistry and Centre of Diagnostics and Therapeutics, Georgia State University Atlanta GA 30303-3083 USA +1 404-413-5505 +1 404-413-5503
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Mansoura University Mansoura 35516 Egypt
- Master of Pharmaceutical Science Program, California North State University Elk Grove CA 95757 USA
| | - Gregory M K Poon
- Department of Chemistry and Centre of Diagnostics and Therapeutics, Georgia State University Atlanta GA 30303-3083 USA +1 404-413-5505 +1 404-413-5503
| | - David W Boykin
- Department of Chemistry and Centre of Diagnostics and Therapeutics, Georgia State University Atlanta GA 30303-3083 USA +1 404-413-5505 +1 404-413-5503
| | - W David Wilson
- Department of Chemistry and Centre of Diagnostics and Therapeutics, Georgia State University Atlanta GA 30303-3083 USA +1 404-413-5505 +1 404-413-5503
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2
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Ogbonna E, Paul A, Farahat AA, Terrell JR, Mineva E, Ogbonna V, Boykin DW, Wilson WD. X-ray Structure Characterization of the Selective Recognition of AT Base Pair Sequences. ACS BIO & MED CHEM AU 2023; 3:335-348. [PMID: 37599788 PMCID: PMC10436263 DOI: 10.1021/acsbiomedchemau.3c00002] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/23/2023] [Accepted: 03/24/2023] [Indexed: 08/22/2023]
Abstract
The rational design of small molecules that target specific DNA sequences is a promising strategy to modulate gene expression. This report focuses on a diamidinobenzimidazole compound, whose selective binding to the minor groove of AT DNA sequences holds broad significance in the molecular recognition of AT-rich human promoter sequences. The objective of this study is to provide a more detailed and systematized understanding, at an atomic level, of the molecular recognition mechanism of different AT-specific sequences by a rationally designed minor groove binder. The specialized method of X-ray crystallography was utilized to investigate how the sequence-dependent recognition properties in general, A-tract, and alternating AT sequences affect the binding of diamidinobenzimidazole in the DNA minor groove. While general and A-tract AT sequences give a narrower minor groove, the alternating AT sequences intrinsically have a wider minor groove which typically constricts upon binding. A strong and direct hydrogen bond between the N-H of the benzimidazole and an H-bond acceptor atom in the minor groove is essential for DNA recognition in all sequences described. In addition, the diamidine compound specifically utilizes an interfacial water molecule for its DNA binding. DNA complexes of AATT and AAAAAA recognition sites show that the diamidine compound can bind in two possible orientations with a preference for water-assisted hydrogen bonding at either cationic end. The complex structures of AAATTT, ATAT, ATATAT, and AAAA are bound in a singular orientation. Analysis of the helical parameters shows a minor groove expansion of about 1 Å across all the nonalternating DNA complexes. The results from this systematic approach will convey a greater understanding of the specific recognition of a diverse array of AT-rich sequences by small molecules and more insight into the design of small molecules with enhanced specificity to AT and mixed DNA sequences.
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Affiliation(s)
- Edwin
N. Ogbonna
- Department
of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303-3083, United States
| | - Ananya Paul
- Department
of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303-3083, United States
| | - Abdelbasset A. Farahat
- Department
of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303-3083, United States
- Department
of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
- Master
of Pharmaceutical Sciences Program, California
North State University, 9700 W Taron Dr., Elk Grove, California 95757, United States
| | - J. Ross Terrell
- Department
of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303-3083, United States
| | - Ekaterina Mineva
- Department
of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303-3083, United States
| | - Victor Ogbonna
- Department
of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303-3083, United States
| | - David W Boykin
- Department
of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303-3083, United States
| | - W. David Wilson
- Department
of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303-3083, United States
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3
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Koester DC, Marx VM, Williams S, Jiricek J, Dauphinais M, René O, Miller SL, Zhang L, Patra D, Chen YL, Cheung H, Gable J, Lakshminarayana SB, Osborne C, Galarneau JR, Kulkarni U, Richmond W, Bretz A, Xiao L, Supek F, Wiesmann C, Honnappa S, Be C, Mäser P, Kaiser M, Ritchie R, Barrett MP, Diagana TT, Sarko C, Rao SPS. Discovery of Novel Quinoline-Based Proteasome Inhibitors for Human African Trypanosomiasis (HAT). J Med Chem 2022; 65:11776-11787. [PMID: 35993839 PMCID: PMC9469205 DOI: 10.1021/acs.jmedchem.2c00791] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Human African Trypanosomiasis (HAT) is a vector-borne disease caused by kinetoplastid parasites of the Trypanosoma genus. The disease proceeds in two stages, with a hemolymphatic blood stage and a meningo-encephalic brain stage. In the latter stage, the parasite causes irreversible damage to the brain leading to sleep cycle disruption and is fatal if untreated. An orally bioavailable treatment is highly desirable. In this study, we present a brain-penetrant, parasite-selective 20S proteasome inhibitor that was rapidly optimized from an HTS singleton hit to drug candidate compound 7 that showed cure in a stage II mouse efficacy model. Here, we describe hit expansion and lead optimization campaign guided by cryo-electron microscopy and an in silico model to predict the brain-to-plasma partition coefficient Kp as an important parameter to prioritize compounds for synthesis. The model combined with in vitro and in vivo experiments allowed us to advance compounds with favorable unbound brain-to-plasma ratios (Kp,uu) to cure a CNS disease such as HAT.
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Affiliation(s)
- Dennis C. Koester
- Global
Discovery Chemistry, Novartis Institutes
for Biomedical Research, Emeryville, California 94608, United States
| | - Vanessa M. Marx
- Global
Discovery Chemistry, Novartis Institutes
for Biomedical Research, Emeryville, California 94608, United States
| | - Sarah Williams
- Global
Discovery Chemistry, Novartis Institutes
for Biomedical Research, Emeryville, California 94608, United States
| | - Jan Jiricek
- Global
Discovery Chemistry, Novartis Institutes
for Biomedical Research, Emeryville, California 94608, United States
| | - Maxime Dauphinais
- Global
Discovery Chemistry, Novartis Institutes
for Biomedical Research, Emeryville, California 94608, United States
| | - Olivier René
- Global
Discovery Chemistry, Novartis Institutes
for Biomedical Research, Emeryville, California 94608, United States
| | - Sarah L. Miller
- Global
Discovery Chemistry, Novartis Institutes
for Biomedical Research, Emeryville, California 94608, United States
| | - Lei Zhang
- Global
Discovery Chemistry, Novartis Institutes
for Biomedical Research, Emeryville, California 94608, United States
| | - Debjani Patra
- Novartis
Institutes for Tropical Diseases, Emeryville, California 94608, United States
| | - Yen-Liang Chen
- Lead
Discovery, Novartis Institutes for Tropical
Diseases, Emeryville, California 94608, United States
| | - Harry Cheung
- Lead
Discovery, Novartis Institutes for Tropical
Diseases, Emeryville, California 94608, United States
| | - Jonathan Gable
- Lead
Discovery, Novartis Institutes for Tropical
Diseases, Emeryville, California 94608, United States
| | - Suresh B. Lakshminarayana
- Pharmacokinetic
Sciences, Novartis Institutes for Tropical
Diseases, Emeryville, California 94608, United States
| | - Colin Osborne
- Pharmacokinetic
Sciences, Pharmacology and Comparative Medicine, Novartis Institutes for Tropical Diseases, Emeryville, California 94608, United States
| | - Jean-Rene Galarneau
- Preclinical
Safety, Novartis Institutes for Biomedical
Research, Cambridge, Massachusetts 02139, United States
| | - Upendra Kulkarni
- Chemical
and Pharmaceutical Profiling, Novartis Institutes
for Biomedical Research, Cambridge, Massachusetts 02139, United States
| | - Wendy Richmond
- Global
Discovery Chemistry, Novartis Institutes
for Biomedical Research, San Diego, California 92121, United States
| | - Angela Bretz
- Global
Discovery Chemistry, Novartis Institutes
for Biomedical Research, San Diego, California 92121, United States
| | - Linda Xiao
- Pharmacology, Novartis Institutes for Tropical Diseases, Emeryville, California 94608, United States
| | - Frantisek Supek
- Novartis
Institutes for Biomedical Research, San Diego, California 92121, United States
| | | | - Srinivas Honnappa
- Novartis
Institutes for Biomedical Research, 4056 Basel, Switzerland
| | - Celine Be
- Novartis
Institutes for Biomedical Research, 4056 Basel, Switzerland
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Kreuzstrasse 2, 4123 Allschwil, Switzerland
- University
of Basel, CH 4000 Basel, Switzerland
| | - Marcel Kaiser
- Swiss Tropical and Public Health Institute, Kreuzstrasse 2, 4123 Allschwil, Switzerland
- University
of Basel, CH 4000 Basel, Switzerland
| | - Ryan Ritchie
- University of Glasgow, University Place, Glasgow G12 8TA, U.K
| | | | - Thierry T. Diagana
- Novartis
Institutes for Tropical Diseases, Emeryville, California 94608, United States
| | - Christopher Sarko
- Global
Discovery Chemistry, Novartis Institutes
for Biomedical Research, Emeryville, California 94608, United States
| | - Srinivasa P. S. Rao
- Novartis
Institutes for Tropical Diseases, Emeryville, California 94608, United States
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4
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Periferakis A, Caruntu A, Periferakis AT, Scheau AE, Badarau IA, Caruntu C, Scheau C. Availability, Toxicology and Medical Significance of Antimony. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19084669. [PMID: 35457536 PMCID: PMC9030621 DOI: 10.3390/ijerph19084669] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/04/2022] [Accepted: 04/10/2022] [Indexed: 01/01/2023]
Abstract
Antimony has been known and used since ancient times, but its applications have increased significantly during the last two centuries. Aside from its few medical applications, it also has industrial applications, acting as a flame retardant and a catalyst. Geologically, native antimony is rare, and it is mostly found in sulfide ores. The main ore minerals of antimony are antimonite and jamesonite. The extensive mining and use of antimony have led to its introduction into the biosphere, where it can be hazardous, depending on its bioavailability and absorption. Detailed studies exist both from active and abandoned mining sites, and from urban settings, which document the environmental impact of antimony pollution and its impact on human physiology. Despite its evident and pronounced toxicity, it has also been used in some drugs, initially tartar emetics and subsequently antimonials. The latter are used to treat tropical diseases and their therapeutic potential for leishmaniasis means that they will not be soon phased out, despite the fact the antimonial resistance is beginning to be documented. The mechanisms by which antimony is introduced into human cells and subsequently excreted are still the subject of research; their elucidation will enable us to better understand antimony toxicity and, hopefully, to improve the nature and delivery method of antimonial drugs.
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Affiliation(s)
- Argyrios Periferakis
- Department of Physiology, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania; (A.P.); (A.-T.P.); (I.A.B.); (C.C.)
- Akadimia of Ancient Greek and Traditional Chinese Medicine, 16675 Athens, Greece
| | - Ana Caruntu
- Department of Oral and Maxillofacial Surgery, The “Carol Davila” Central Military Emergency Hospital, 010825 Bucharest, Romania
- Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine, “Titu Maiorescu” University, 031593 Bucharest, Romania
- Correspondence: (A.C.); (C.S.)
| | - Aristodemos-Theodoros Periferakis
- Department of Physiology, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania; (A.P.); (A.-T.P.); (I.A.B.); (C.C.)
| | - Andreea-Elena Scheau
- Department of Radiology and Medical Imaging, Fundeni Clinical Institute, 022328 Bucharest, Romania;
| | - Ioana Anca Badarau
- Department of Physiology, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania; (A.P.); (A.-T.P.); (I.A.B.); (C.C.)
| | - Constantin Caruntu
- Department of Physiology, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania; (A.P.); (A.-T.P.); (I.A.B.); (C.C.)
- Department of Dermatology, Prof. N.C. Paulescu National Institute of Diabetes, Nutrition and Metabolic Diseases, 011233 Bucharest, Romania
| | - Cristian Scheau
- Department of Physiology, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania; (A.P.); (A.-T.P.); (I.A.B.); (C.C.)
- Correspondence: (A.C.); (C.S.)
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5
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A. Ismail M, M. El-Sayed W, Shaaban S, A. Abdelwahab G, S. Hamama W. A Review of Cationic Arylfurans and Their Isosteres: Synthesis and Biological Importance. CURR ORG CHEM 2020. [DOI: 10.2174/1385272823666191029114830] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The present study provides an overview of the chemistry and biological importance
of the cationic chalcophene derivatives (furans, thiophenes and selenophenes). The
summarized literature survey includes synthetic methods, reactivity and biological activities
of aryl/hetarylchalcophenes that have been reported mainly from 2001 to 2019 focusing
on monochalcophenes. A discussion demonstrating the proposed mechanisms of some
interesting synthetic routes and linking structure features to biological activities is presented.
These classes of compounds including cationic chalcophenes possess antiproliferative,
antimicrobial and antiprotozoal activities. This review highlights recent advances
for arylchalcophene derivatives and may contribute to the design and structure optimization
of new chalcophene derivatives in the future.
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Affiliation(s)
- Mohamed A. Ismail
- Department of Chemistry, Faculty of Science, Mansoura University, Mansoura 35516, Egypt
| | - Wael M. El-Sayed
- Department of Zoology, Faculty of Science, University of Ain Shams, Abbassia 11566, Cairo, Egypt
| | - Saad Shaaban
- Department of Chemistry, Faculty of Science, Mansoura University, Mansoura 35516, Egypt
| | - Ghada A. Abdelwahab
- Department of Chemistry, Faculty of Science, Mansoura University, Mansoura 35516, Egypt
| | - Wafaa S. Hamama
- Department of Chemistry, Faculty of Science, Mansoura University, Mansoura 35516, Egypt
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6
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Indole and Benzimidazole Bichalcophenes: Synthesis, DNA Binding and Antiparasitic Activity. Eur J Med Chem 2017; 143:1590-1596. [PMID: 29126729 PMCID: PMC5744864 DOI: 10.1016/j.ejmech.2017.10.056] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Revised: 10/13/2017] [Accepted: 10/18/2017] [Indexed: 11/20/2022]
Abstract
A novel series of indole and benzimidazole bichalcophene diamidine derivatives were prepared to study their antimicrobial activity against the tropical parasites causing African sleeping sickness and malaria. The dicyanoindoles needed to synthesize the target diamidines were obtained through Stille coupling reactions while the bis-cyanobenzimidazoles intermediates were made via condensation/cyclization reactions of different aldehydes with 4-cyano-1,2-diaminobenzene. Different amidine synthesis methodologies namely, lithium bis-trimethylsilylamide (LiN[Si(CH3)3]2) and Pinner methods were used to prepare the diamidines. Both types (indole and benzimidazole) derivatives of the new diamidines bind strongly with the DNA minor groove and generally show excellent in vitro antitrypanosomal activity. The diamidino-indole derivatives also showed excellent in vitro antimalarial activity while their benzimidazole counterparts were generally less active. Compound 7c was highly active in vivo and cured all mice infected with Trypanosoma brucei rhodesiense, a model that mimics the acute stage of African sleeping sickness, at a low dose of 4 × 5 mg/kg i.p. and hence 7c is more potent in vivo than pentamidine.
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7
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Ji Y, Varkevisser R, Opacic D, Bossu A, Kuiper M, Beekman JDM, Yang S, Khan AP, Dobrev D, Voigt N, Wang MZ, Verheule S, Vos MA, van der Heyden MAG. The inward rectifier current inhibitor PA-6 terminates atrial fibrillation and does not cause ventricular arrhythmias in goat and dog models. Br J Pharmacol 2017; 174:2576-2590. [PMID: 28542844 PMCID: PMC5513871 DOI: 10.1111/bph.13869] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 05/16/2017] [Accepted: 05/16/2017] [Indexed: 01/24/2023] Open
Abstract
Background and Purpose The density of the inward rectifier current (IK1) increases in atrial fibrillation (AF), shortening effective refractory period and thus promoting atrial re‐entry. The synthetic compound pentamidine analogue 6 (PA‐6) is a selective and potent IK1 inhibitor. We tested PA‐6 for anti‐AF efficacy and potential proarrhythmia, using established models in large animals. Experimental Approach PA‐6 was applied i.v. in anaesthetized goats with rapid pacing‐induced AF and anaesthetized dogs with chronic atrio‐ventricular (AV) block. Electrophysiological and pharmacological parameters were determined. Key Results PA‐6 (2.5 mg·kg−1·10 min−1) induced cardioversion to sinus rhythm (SR) in 5/6 goats and prolonged AF cycle length. AF complexity decreased significantly before cardioversion. PA‐6 accumulated in cardiac tissue with ratios between skeletal muscle : atrial muscle : ventricular muscle of approximately 1:8:21. In SR dogs, PA‐6 peak plasma levels 10 min post infusion were 5.5 ± 0.9 μM, PA‐6 did not induce significant prolongation of QTc and did not affect heart rate, PQ or QRS duration. In dogs with chronic AV block, PA‐6 did not affect QRS but lengthened QTc during the experiment, but not chronically. PA‐6 did not induce TdP arrhythmias in nine animals (0/9) in contrast to dofetilide (5/9). PA‐6 (200 nM) inhibited IK1, but not IK,ACh, in human isolated atrial cardiomyocytes. Conclusion and Implications PA‐6 restored SR in goats with persistent AF and, in dogs with chronic AV block, prolonged QT intervals, without inducing TdP arrhythmias. Our results demonstrate cardiac safety and good anti‐AF properties for PA‐6.
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Affiliation(s)
- Yuan Ji
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rosanne Varkevisser
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dragan Opacic
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
| | - Alexandre Bossu
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marion Kuiper
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
| | - Jet D M Beekman
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Sihyung Yang
- Department of Pharmaceutical Chemistry, School of Pharmacy, The University of Kansas, Lawrence, KS, USA
| | - Azinwi Phina Khan
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Dobromir Dobrev
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Niels Voigt
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany.,Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Göttingen, Germany
| | - Michael Zhuo Wang
- Department of Pharmaceutical Chemistry, School of Pharmacy, The University of Kansas, Lawrence, KS, USA
| | - Sander Verheule
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
| | - Marc A Vos
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
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8
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Armstrong LC, Kirsch GE, Fedorov NB, Wu C, Kuryshev YA, Sewell AL, Liu Z, Motter AL, Leggett CS, Orr MS. High-Throughput Patch Clamp Screening in Human α6-Containing Nicotinic Acetylcholine Receptors. SLAS DISCOVERY 2017; 22:686-695. [PMID: 28298165 PMCID: PMC5480602 DOI: 10.1177/2472555217696794] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Nicotine, the addictive component of tobacco products, is an agonist at nicotinic acetylcholine receptors (nAChRs) in the brain. The subtypes of nAChR are defined by their α- and β-subunit composition. The α6β2β3 nAChR subtype is expressed in terminals of dopaminergic neurons that project to the nucleus accumbens and striatum and modulate dopamine release in brain regions involved in nicotine addiction. Although subtype-dependent selectivity of nicotine is well documented, subtype-selective profiles of other tobacco product constituents are largely unknown and could be essential for understanding the addiction-related neurological effects of tobacco products. We describe the development and validation of a recombinant cell line expressing human α6/3β2β3V273S nAChR for screening and profiling assays in an automated patch clamp platform (IonWorks Barracuda). The cell line was pharmacologically characterized by subtype-selective and nonselective reference agonists, pore blockers, and competitive antagonists. Agonist and antagonist effects detected by the automated patch clamp approach were comparable to those obtained by conventional electrophysiological assays. A pilot screen of a library of Food and Drug Administration–approved drugs identified compounds, previously not known to modulate nAChRs, which selectively inhibited the α6/3β2β3V273S subtype. These assays provide new tools for screening and subtype-selective profiling of compounds that act at α6β2β3 nicotinic receptors.
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Affiliation(s)
| | | | | | - Caiyun Wu
- 1 Charles River Discovery, Cleveland, OH, USA
| | | | | | - Zhiqi Liu
- 1 Charles River Discovery, Cleveland, OH, USA
| | - Arianne L Motter
- 2 U.S. Food and Drug Administration/Center for Tobacco Products, Silver Spring, MD, USA
| | - Carmine S Leggett
- 2 U.S. Food and Drug Administration/Center for Tobacco Products, Silver Spring, MD, USA
| | - Michael S Orr
- 2 U.S. Food and Drug Administration/Center for Tobacco Products, Silver Spring, MD, USA.,PAREXEL International, Bethesda, MD, USA
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9
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Abstract
Pathogenic animal trypanosomes affecting livestock have represented a major constraint to agricultural development in Africa for centuries, and their negative economic impact is increasing in South America and Asia. Chemotherapy and chemoprophylaxis represent the main means of control. However, research into new trypanocides has remained inadequate for decades, leading to a situation where the few compounds available are losing efficacy due to the emergence of drug-resistant parasites. In this review, we provide a comprehensive overview of the current options available for the treatment and prophylaxis of the animal trypanosomiases, with a special focus on the problem of resistance. The key issues surrounding the main economically important animal trypanosome species and the diseases they cause are also presented. As new investment becomes available to develop improved tools to control the animal trypanosomiases, we stress that efforts should be directed towards a better understanding of the biology of the relevant parasite species and strains, to identify new drug targets and interrogate resistance mechanisms.
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Skinner-Adams TS, Sumanadasa SD, Fisher GM, Davis RA, Doolan DL, Andrews KT. Defining the targets of antiparasitic compounds. Drug Discov Today 2016; 21:725-39. [DOI: 10.1016/j.drudis.2016.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/04/2015] [Accepted: 01/07/2016] [Indexed: 10/22/2022]
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11
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Youssef MM, Arafa RK, Ismail MA. Synthesis, antimicrobial, and antiproliferative activities of substituted phenylfuranylnicotinamidines. Drug Des Devel Ther 2016; 10:1133-46. [PMID: 27042005 PMCID: PMC4795586 DOI: 10.2147/dddt.s102128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
This research work deals with the design and synthesis of a series of substituted phenylfuranylnicotinamidines 4a-i. Facile preparation of the target compounds was achieved by Suzuki coupling-based synthesis of the nitrile precursors 3a-i, followed by their conversion to the corresponding nicotinamidines 4a-i utilizing LiN(TMS)2. The antimicrobial activities of the newly synthesized nicotinamidine derivatives were evaluated against the Gram-negative bacterial strains Escherichia coli and Pseudomonas aeruginosa as well as the Gram-positive bacterial strains Staphylococcus aureus and Bacillus megaterium. The minimum inhibitory concentration values of nicotinamidines against all tested microorganisms were in the range of 10-20 μM. In specific, compounds 4a and 4b showed excellent minimum inhibitory concentration values of 10 μM against Staphylococcus aureus bacterial strain and were similar to ampicillin as an antibacterial reference. On the other hand, selected nicotinamidine derivatives were biologically screened for their cytotoxic activities against a panel of 60 cell lines representing nine types of human cancer at a single high dose at National Cancer Institute, Bethesda, MD, USA. Nicotinamidines showing promising activities were further assessed in a five-dose screening assay to determine their compound concentration causing 50% growth inhibition of tested cell (GI50), compound concentration causing 100% growth inhibition of tested cell (TGI), and compound concentration causing 50% lethality of tested cell (LC50) values. Structure-activity relationship studies demonstrated that the activity of members of this series can be modulated from cytostatic to cytotoxic based on the substitution pattern/nature on the terminal phenyl ring. The most active compound was found to be 4e displaying a submicromolar GI50 value of 0.83 μM, with TGI and LC50 values of 2.51 and 100 μM, respectively. Finally, the possible underlying mechanism of action of this series of compounds was investigated by determining their nuclease-like DNA degradation ability in addition to their antioxidant power and all monocations proved to be effective in all assays.
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Affiliation(s)
- Magdy M Youssef
- Department of Chemistry, College of Science, King Faisal University, Hofuf, Saudi Arabia
- Department of Chemistry, Faculty of Science, Mansoura University, Mansoura, Egypt
| | - Reem K Arafa
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt
- Biomedical Sciences Program, University of Science and Technology, Zewail City of Science and Technology, Cairo, Egypt
| | - Mohamed A Ismail
- Department of Chemistry, College of Science, King Faisal University, Hofuf, Saudi Arabia
- Department of Chemistry, Faculty of Science, Mansoura University, Mansoura, Egypt
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12
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A new approach to chemotherapy: drug-induced differentiation kills African trypanosomes. Sci Rep 2016; 6:22451. [PMID: 26931380 PMCID: PMC4773815 DOI: 10.1038/srep22451] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 02/10/2016] [Indexed: 12/16/2022] Open
Abstract
Human African trypanosomiasis (sleeping sickness) is a neglected tropical disease caused by Trypanosoma brucei spp. The parasites are transmitted by tsetse flies and adapt to their different hosts and environments by undergoing a series of developmental changes. During differentiation, the trypanosome alters its protein coat. Bloodstream form trypanosomes in humans have a coat of variant surface glycoprotein (VSG) that shields them from the immune system. The procyclic form, the first life-cycle stage to develop in the tsetse fly, replaces the VSG coat by procyclins; these proteins do not protect the parasite from lysis by serum components. Our study exploits the parasite-specific process of differentiation from bloodstream to procyclic forms to screen for potential drug candidates. Using transgenic trypanosomes with a reporter gene in a procyclin locus, we established a whole-cell assay for differentiation in a medium-throughput format. We screened 7,495 drug-like compounds and identified 28 hits that induced expression of the reporter and loss of VSG at concentrations in the low micromolar range. Small molecules that induce differentiation to procyclic forms could facilitate studies on the regulation of differentiation as well as serving as scaffolds for medicinal chemistry for new treatments for sleeping sickness.
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13
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Kaiser M, Maes L, Tadoori LP, Spangenberg T, Ioset JR. Repurposing of the Open Access Malaria Box for Kinetoplastid Diseases Identifies Novel Active Scaffolds against Trypanosomatids. ACTA ACUST UNITED AC 2015; 20:634-45. [PMID: 25690568 DOI: 10.1177/1087057115569155] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 01/02/2015] [Indexed: 01/06/2023]
Abstract
Phenotypic screening had successfully been used for hit generation, especially in the field of neglected diseases, in which feeding the drug pipeline with new chemotypes remains a constant challenge. Here, we catalyze drug discovery research using a publicly available screening tool to boost drug discovery. The Malaria Box, assembled by the Medicines for Malaria Venture, is a structurally diverse set of 200 druglike and 200 probelike compounds distilled from more than 20,000 antimalarial hits from corporate and academic libraries. Repurposing such compounds has already identified new scaffolds against cryptosporidiosis and schistosomiasis. In addition to initiating new hit-to-lead activities, screening the Malaria Box against a plethora of other parasites would enable the community to better understand the similarities and differences between them. We describe the screening of the Malaria Box and triaging of the identified hits against kinetoplastids responsible for human African trypanosomiasis (Trypanosoma brucei), Chagas disease (Trypanosoma cruzi), and visceral leishmaniasis (Leishmania donovani and Leishmania infantum). The in vitro and in vivo profiling of the most promising active compounds with respect to efficacy, toxicity, pharmacokinetics, and complementary druggable properties are presented and a collaborative model used as a way to accelerate the discovery process discussed.
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Affiliation(s)
- Marcel Kaiser
- Parasite Chemotherapy, Swiss Tropical and Public Health Institute, Basel, Switzerland University of Basel, Basel, Switzerland
| | - Louis Maes
- Laboratory of Microbiology, Parasitology and Hygiene, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Antwerp University, Antwerp, Belgium
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14
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Thuita JK, Wolf KK, Murilla GA, Bridges AS, Boykin DW, Mutuku JN, Liu Q, Jones SK, Gem CO, Ching S, Tidwell RR, Wang MZ, Paine MF, Brun R. Chemotherapy of second stage human African trypanosomiasis: comparison between the parenteral diamidine DB829 and its oral prodrug DB868 in vervet monkeys. PLoS Negl Trop Dis 2015; 9:e0003409. [PMID: 25654243 PMCID: PMC4318582 DOI: 10.1371/journal.pntd.0003409] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 11/12/2014] [Indexed: 11/18/2022] Open
Abstract
Human African trypanosomiasis (HAT, sleeping sickness) ranks among the most neglected tropical diseases based on limited availability of drugs that are safe and efficacious, particularly against the second stage (central nervous system [CNS]) of infection. In response to this largely unmet need for new treatments, the Consortium for Parasitic Drug Development developed novel parenteral diamidines and corresponding oral prodrugs that have shown cure of a murine model of second stage HAT. As a rationale for selection of one of these compounds for further development, the pharmacokinetics and efficacy of intramuscular (IM) active diamidine 2,5-bis(5-amidino-2-pyridyl)furan (DB829; CPD-0802) and oral prodrug2,5-bis[5-(N-methoxyamidino)-2-pyridyl]furan (DB868) were compared in the vervet monkey model of second stage HAT. Treatment was initiated 28 days post-infection of monkeys with T. b. rhodesiense KETRI 2537. Results showed that IM DB829 at 5 mg/kg/day for 5 consecutive days, 5 mg/kg/day every other day for 5 doses, or 2.5 mg/kg/day for 5 consecutive days cured all monkeys (5/5). Oral DB868 was less successful, with no cures (0/2) at 3 mg/kg/day for 10 days and cure rates of 1/4 at 10 mg/kg/day for 10 days and 20 mg/kg/day for 10 days; in total, only 2/10 monkeys were cured with DB868 dose regimens. The geometric mean plasma Cmax of IM DB829 at 5 mg/kg following the last of 5 doses was 25-fold greater than that after 10 daily oral doses of DB868 at 20 mg/kg. These data suggest that the active diamidine DB829, administered IM, should be considered for further development as a potential new treatment for second stage HAT. Treatment of human African trypanosomiasis (HAT, sleeping sickness) suffers from a shortage of medicines that are both effective, especially against the second (late) stage of the disease, and safe for patients. The development of new HAT medicines also has been significantly influenced by the perceived need for easily administered oral medicines to reduce the need for hospitalization of patients in resource-poor settings where HAT typically occurs. However, the clinical status of second stage patients is likely to dictate the need for their hospitalization, thus both oral and parenterally administered medicines would be utilised effectively. Therefore, in an effort to develop new medicines that meet efficacy and safety requirements, we evaluated a novel injectable diamidine 2,5-bis(5-amidino-2-pyridyl)furan (DB829; CPD-0802) and its oral prodrug formulation 2,5-bis[5-(N-methoxyamidino)-2-pyridyl]furan (DB868) in the vervet monkey model of second stage HAT. Treatment with either compound was initiated 28 days post-infection of monkeys with T. b. rhodesiense KETRI 2537. DB829 was dosed at 5 mg/kg/day for 5 consecutive days, 5 mg/kg/day every other day for 5 doses or 2.5 mg/kg/day for 5 consecutive days intramuscularly (IM) while DB868 was administered at 20, 10 or 3 mg/kg/day for 10 consecutive days orally. Clinical and parasitological monitoring was carried out for at least 300 days before the monkeys were declared cured. All IM DB829 and oral DB868 dose regimens were well tolerated. In addition, all monkeys (5/5) treated with IM DB829 were confirmed cured. In contrast, oral DB868 cured only 1/4 monkeys at either 10 or 20 mg/kg and did not cure any monkey when dosed at 3 mg/kg. These results indicate that IM DB829 is a suitable compound for further development as treatment for second stage HAT.
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Affiliation(s)
- John K. Thuita
- Trypanosomiasis Research Centre, Kenya Agricultural Research Institute (TRC-KARI), Kikuyu, Kenya
- * E-mail: ,
| | - Kristina K. Wolf
- University of North Carolina Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Grace A. Murilla
- Trypanosomiasis Research Centre, Kenya Agricultural Research Institute (TRC-KARI), Kikuyu, Kenya
| | - Arlene S. Bridges
- Department of Pathology and Laboratory Medicine, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - David W. Boykin
- Department of Chemistry, Georgia State University, Atlanta, Georgia, United States of America
| | - James N. Mutuku
- Trypanosomiasis Research Centre, Kenya Agricultural Research Institute (TRC-KARI), Kikuyu, Kenya
| | - Qiang Liu
- University of North Carolina Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Susan K. Jones
- Department of Pathology and Laboratory Medicine, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Charles O. Gem
- Trypanosomiasis Research Centre, Kenya Agricultural Research Institute (TRC-KARI), Kikuyu, Kenya
| | - Shelley Ching
- SVC Associates, Inc., Apex, North Carolina, United States of America
| | - Richard R. Tidwell
- Department of Pathology and Laboratory Medicine, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Michael Z. Wang
- Department of Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas, United States of America
| | - Mary F. Paine
- University of North Carolina Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Reto Brun
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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15
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Bis-benzimidazole hits against Naegleria fowleri discovered with new high-throughput screens. Antimicrob Agents Chemother 2015; 59:2037-44. [PMID: 25605363 DOI: 10.1128/aac.05122-14] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Naegleria fowleri is a pathogenic free-living amoeba (FLA) that causes an acute fatal disease known as primary amoebic meningoencephalitis (PAM). The major problem for infections with any pathogenic FLA is a lack of effective therapeutics, since PAM has a case mortality rate approaching 99%. Clearly, new drugs that are potent and have rapid onset of action are needed to enhance the treatment regimens for PAM. Diamidines have demonstrated potency against multiple pathogens, including FLA, and are known to cross the blood-brain barrier to cure other protozoan diseases of the central nervous system. Therefore, amidino derivatives serve as an important chemotype for discovery of new drugs. In this study, we validated two new in vitro assays suitable for medium- or high-throughput drug discovery and used these for N. fowleri. We next screened over 150 amidino derivatives of multiple structural classes and identified two hit series with nM potency that are suitable for further lead optimization as new drugs for this neglected disease. These include both mono- and diamidino derivatives, with the most potent compound (DB173) having a 50% inhibitory concentration (IC50) of 177 nM. Similarly, we identified 10 additional analogues with IC50s of <1 μM, with many of these having reasonable selectivity indices. The most potent hits were >500 times more potent than pentamidine. In summary, the mono- and diamidino derivatives offer potential for lead optimization to develop new drugs to treat central nervous system infections with N. fowleri.
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16
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Eperon G, Balasegaram M, Potet J, Mowbray C, Valverde O, Chappuis F. Treatment options for second-stage gambiense human African trypanosomiasis. Expert Rev Anti Infect Ther 2014; 12:1407-17. [PMID: 25204360 PMCID: PMC4743611 DOI: 10.1586/14787210.2014.959496] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Treatment of second-stage gambiense human African trypanosomiasis relied on toxic arsenic-based derivatives for over 50 years. The availability and subsequent use of eflornithine, initially in monotherapy and more recently in combination with nifurtimox (NECT), has drastically improved the prognosis of treated patients. However, NECT logistic and nursing requirements remain obstacles to its deployment and use in peripheral health structures in rural sub-Saharan Africa. Two oral compounds, fexinidazole and SCYX-7158, are currently in clinical development. The main scope of this article is to discuss the potential impact of new oral therapies to improve diagnosis-treatment algorithms and patients' access to treatment, and to contribute to reach the objectives of the recently launched gambiense human African trypanosomiasis elimination program.
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Affiliation(s)
| | | | - Julien Potet
- Geneva University Hospitals,
Geneva, Switzerland
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17
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Sekhar GN, Watson CP, Fidanboylu M, Sanderson L, Thomas SA. Delivery of antihuman African trypanosomiasis drugs across the blood-brain and blood-CSF barriers. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 71:245-75. [PMID: 25307219 DOI: 10.1016/bs.apha.2014.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Human African trypanosomiasis (HAT or sleeping sickness) is a potentially fatal disease caused by the parasite, Trypanosoma brucei sp. The parasites are transmitted by the bite of insect vectors belonging to the genus Glossina (tsetse flies) and display a life cycle strategy that is equally spread between human and insect hosts. T.b. gambiense is found in western and central Africa whereas, T.b. rhodesiense is found in eastern and southern Africa. The disease has two clinical stages: a blood stage after the bite of an infected tsetse fly, followed by a central nervous system (CNS) stage where the parasite penetrates the brain; causing death if left untreated. The blood-brain barrier (BBB) makes the CNS stage difficult to treat because it prevents 98% of all known compounds from entering the brain, including some anti-HAT drugs. Those that do enter the brain are toxic compounds in their own right and have serious side effects. There are only a few drugs available to treat HAT and those that do are stage specific. This review summarizes the incidence, diagnosis, and treatment of HAT and provides a close examination of the BBB transport of anti-HAT drugs and an overview of the latest drugs in development.
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Affiliation(s)
- Gayathri N Sekhar
- King's College London, Institute of Pharmaceutical Sciences, London, United Kingdom
| | - Christopher P Watson
- King's College London, Institute of Pharmaceutical Sciences, London, United Kingdom
| | - Mehmet Fidanboylu
- King's College London, Institute of Pharmaceutical Sciences, London, United Kingdom
| | - Lisa Sanderson
- King's College London, Institute of Pharmaceutical Sciences, London, United Kingdom
| | - Sarah A Thomas
- King's College London, Institute of Pharmaceutical Sciences, London, United Kingdom.
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18
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In vitro and in vivo evaluation of 28DAP010, a novel diamidine for treatment of second-stage African sleeping sickness. Antimicrob Agents Chemother 2014; 58:4452-63. [PMID: 24867978 DOI: 10.1128/aac.02309-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
African sleeping sickness is a neglected tropical disease transmitted by tsetse flies. New and better drugs are still needed especially for its second stage, which is fatal if untreated. 28DAP010, a dipyridylbenzene analogue of DB829, is the second simple diamidine found to cure mice with central nervous system infections by a parenteral route of administration. 28DAP010 showed efficacy similar to that of DB829 in dose-response studies in mouse models of first- and second-stage African sleeping sickness. The in vitro time to kill, determined by microcalorimetry, and the parasite clearance time in mice were shorter for 28DAP010 than for DB829. No cross-resistance was observed between 28DAP010 and pentamidine on the tested Trypanosoma brucei gambiense isolates from melarsoprol-refractory patients. 28DAP010 is the second promising preclinical candidate among the diamidines for the treatment of second-stage African sleeping sickness.
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19
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Pharmacokinetic comparison to determine the mechanisms underlying the differential efficacies of cationic diamidines against first- and second-stage human African trypanosomiasis. Antimicrob Agents Chemother 2014; 58:4064-74. [PMID: 24798280 DOI: 10.1128/aac.02605-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Human African trypanosomiasis (HAT), a neglected tropical disease, is fatal without treatment. Pentamidine, a cationic diamidine, has been used to treat first-stage (hemolymphatic) HAT since the 1940s, but it is ineffective against second-stage (meningoencephalitic, or central nervous system [CNS]) infection. Novel diamidines (DB75, DB820, and DB829) have shown promising efficacy in both mouse and monkey models of first-stage HAT. However, only DB829 cured animals with second-stage infection. In this study, we aimed to determine the mechanisms underlying the differential efficacies of these diamidines against HAT by conducting a comprehensive pharmacokinetic characterization. This included the determination of metabolic stability in liver microsomes, permeability across MDCK and MDR1-MDCK cell monolayers, interaction with the efflux transporter MDR1 (P-glycoprotein 1 or P-gp), drug binding in plasma and brain, and plasma and brain concentration-time profiles after a single dose in mice. The results showed that DB829, an azadiamidine, had the highest systemic exposure and brain-to-plasma ratio, whereas pentamidine and DB75 had the lowest. None of these diamidines was a P-gp substrate, and the binding of each to plasma proteins and brain differed greatly. The brain-to-plasma ratio best predicted the relative efficacies of these diamidines in mice with second-stage infection. In conclusion, pharmacokinetics and CNS penetration influenced the in vivo efficacies of cationic diamidines against first- and second-stage HAT and should be considered when developing CNS-active antitrypanosomal diamidines.
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20
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Independence from Kinetoplast DNA maintenance and expression is associated with multidrug resistance in Trypanosoma brucei in vitro. Antimicrob Agents Chemother 2014; 58:2925-8. [PMID: 24550326 PMCID: PMC3993240 DOI: 10.1128/aac.00122-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
It is well known that several antitrypanosomatid drugs accumulate in the parasite's mitochondrion, where they often bind to the organellar DNA, the kinetoplast. To what extent this property relates to the mode of action of these compounds has remained largely unquantified. Here we show that single point mutations that remove the dependence of laboratory strains of the sleeping sickness parasite Trypanosoma brucei on a functional kinetoplast result in significant resistance to the diamidine and phenanthridine drug classes.
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