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Lenière AC, Vlandas A, Follet J. Treating cryptosporidiosis: A review on drug discovery strategies. Int J Parasitol Drugs Drug Resist 2024; 25:100542. [PMID: 38669849 PMCID: PMC11066572 DOI: 10.1016/j.ijpddr.2024.100542] [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] [Received: 11/28/2023] [Revised: 04/15/2024] [Accepted: 04/18/2024] [Indexed: 04/28/2024]
Abstract
Despite several decades of research on therapeutics, cryptosporidiosis remains a major concern for human and animal health. Even though this field of research to assess antiparasitic drug activity is highly active and competitive, only one molecule is authorized to be used in humans. However, this molecule was not efficacious in immunocompromised people and the lack of animal therapeutics remains a cause of concern. Indeed, the therapeutic arsenal needs to be developed for both humans and animals. Our work aims to clarify research strategies that historically were diffuse and poorly directed. This paper reviews in vitro and in vivo methodologies to assess the activity of future therapeutic compounds by screening drug libraries or through drug repurposing. It focuses on High Throughput Screening methodologies (HTS) and discusses the lack of knowledge of target mechanisms. In addition, an overview of several specific metabolic pathways and enzymatic activities used as targets against Cryptosporidium is provided. These metabolic processes include glycolytic pathways, fatty acid production, kinase activities, tRNA elaboration, nucleotide synthesis, gene expression and mRNA maturation. As a conclusion, we highlight emerging future strategies for screening natural compounds and assessing drug resistance issues.
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Affiliation(s)
- Anne-Charlotte Lenière
- University of Lille, CNRS, Centrale Lille, Junia, Université Polytechnique Hauts de France, UMR 8520, IEMN Institut d'Electronique de Microélectronique et de Nanotechnologie, F, 59000, Lille, France
| | - Alexis Vlandas
- University of Lille, CNRS, Centrale Lille, Junia, Université Polytechnique Hauts de France, UMR 8520, IEMN Institut d'Electronique de Microélectronique et de Nanotechnologie, F, 59000, Lille, France
| | - Jérôme Follet
- University of Lille, CNRS, Centrale Lille, Junia, Université Polytechnique Hauts de France, UMR 8520, IEMN Institut d'Electronique de Microélectronique et de Nanotechnologie, F, 59000, Lille, France.
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2
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Ayoub N, Gedeon A, Munier-Lehmann H. A journey into the regulatory secrets of the de novo purine nucleotide biosynthesis. Front Pharmacol 2024; 15:1329011. [PMID: 38444943 PMCID: PMC10912719 DOI: 10.3389/fphar.2024.1329011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 02/01/2024] [Indexed: 03/07/2024] Open
Abstract
De novo purine nucleotide biosynthesis (DNPNB) consists of sequential reactions that are majorly conserved in living organisms. Several regulation events take place to maintain physiological concentrations of adenylate and guanylate nucleotides in cells and to fine-tune the production of purine nucleotides in response to changing cellular demands. Recent years have seen a renewed interest in the DNPNB enzymes, with some being highlighted as promising targets for therapeutic molecules. Herein, a review of two newly revealed modes of regulation of the DNPNB pathway has been carried out: i) the unprecedent allosteric regulation of one of the limiting enzymes of the pathway named inosine 5'-monophosphate dehydrogenase (IMPDH), and ii) the supramolecular assembly of DNPNB enzymes. Moreover, recent advances that revealed the therapeutic potential of DNPNB enzymes in bacteria could open the road for the pharmacological development of novel antibiotics.
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Affiliation(s)
- Nour Ayoub
- Institut Pasteur, Université Paris Cité, INSERM UMRS-1124, Paris, France
| | - Antoine Gedeon
- Sorbonne Université, École Normale Supérieure, Université PSL, CNRS UMR7203, Laboratoire des Biomolécules, LBM, Paris, France
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3
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Asmare MM, Nitin N, Yun SI, Mahapatra RK. QSAR and deep learning model for virtual screening of potential inhibitors against Inosine 5' Monophosphate dehydrogenase (IMPDH) of Cryptosporidium parvum. J Mol Graph Model 2021; 111:108108. [PMID: 34911011 DOI: 10.1016/j.jmgm.2021.108108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 12/07/2021] [Indexed: 01/08/2023]
Abstract
Cryptosporidium parvum (Cp) causes a gastro-intestinal disease called Cryptosporidiosis. C. parvum Inosine 5' monophosphate dehydrogenase (CpIMPDH) is responsible for the production of guanine nucleotides. In the present study, 37 known urea-based congeneric compounds were used to build a 2D and 3D QSAR model against CpIMPDH. The built models were validated based on OECD principles. A deep learning model was adopted from a framework called Deep Purpose. The model was trained with 288 known active compounds and validated using a test set. From the training set of the 3D QSAR, a pharmacophore model was built and the best pharmacophore hypotheses were scored and sorted using a phase-hypo score. A phytochemical database was screened using both the pharmacophore model and a deep learning model. The screened compounds were considered for glide XP docking, followed by quantum polarized ligand docking. Finally, the best compound among them was considered for molecular dynamics simulation study.
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Affiliation(s)
| | - Nitin Nitin
- Department of Food Science and Technology, University of California, Davis, Davis, CA, USA
| | - Soon-Il Yun
- Department of Food Science and Technology, Jeonbuk National University, Jeonju, 54896, Republic of Korea; Department of Agricultural Convergence Technology, Jeonbuk National University, Jeonju, 54896, Republic of Korea.
| | - Rajani Kanta Mahapatra
- School of Biotechnology, KIIT Deemed to be University, Bhubaneswar, 751024, Odisha, India.
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Omolabi KF, Agoni C, Olotu FA, Soliman ME. ‘Finding the needle in the haystack’- will natural products fit for purpose in the treatment of cryptosporidiosis? – A theoretical perspective. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2021.1895435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Kehinde F. Omolabi
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Clement Agoni
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Fisayo A. Olotu
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Mahmoud E.S. Soliman
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
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5
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A probable means to an end: exploring P131 pharmacophoric scaffold to identify potential inhibitors of Cryptosporidium parvum inosine monophosphate dehydrogenase. J Mol Model 2021; 27:35. [PMID: 33423140 DOI: 10.1007/s00894-020-04663-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 12/27/2020] [Indexed: 10/22/2022]
Abstract
Compound P131 has been established to inhibit Cryptosporidium parvum's inosine monophosphate dehydrogenase (CpIMPDH). Its inhibitory activity supersedes that of paromomycin, which is extensively used in treating cryptosporidiosis. Through the per-residue energy decomposition approach, crucial moieties of P131 were identified and subsequently adopted to create a pharmacophore model for virtual screening in the ZINC database. This search generated eight ADMET-compliant hits that were examined thoroughly to fit into the active site of CpIMPDH via molecular docking. Three compounds ZINC46542062, ZINC58646829, and ZINC89780094, with favorable docking scores of - 8.3 kcal/mol, - 8.2 kcal/mol, and - 7.5 kcal/mol, were selected. The potential inhibitory mechanism of these compounds was probed using molecular dynamics simulation and Molecular Mechanics Generalized Poisson Boltzmann Surface Area (MM/PBSA) analyses. Results revealed that one of the hits (ZINC46542062) exhibited a lower binding free energy of - 39.52 kcal/mol than P131, which had - 34.6 kcal/mol. Conformational perturbation induced by the binding of the identified hits to CpIMPDH was similar to P131, suggesting a similarity in inhibitory mechanisms. Also, in silico investigation of the properties of the hit compounds implied superior physicochemical properties with regards to their synthetic accessibility, lipophilicity, and number of hydrogen bond donors and acceptors in comparison with P131. ZINC46542062 was identified as a promising hit compound with the highest binding affinity to the target protein and favorable physicochemical and pharmacokinetic properties relative to P131. The identified compounds can serve as a basis for conducting further experimental investigations toward the development of anticryptosporidials, which can overcome the challenges of existing therapeutic options. Graphical abstract P131 and the identified compounds docked in the NAD+ binding site of Cryptosporidium parvum IMPDH.
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Identification of novel anti-cryptosporidial inhibitors through a combined approach of pharmacophore modeling, virtual screening, and molecular docking. INFORMATICS IN MEDICINE UNLOCKED 2021. [DOI: 10.1016/j.imu.2021.100583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Lee S, Ku AF, Vippila MR, Wang Y, Zhang M, Wang X, Hedstrom L, Cuny GD. Mycophenolic anilides as broad specificity inosine-5'-monophosphate dehydrogenase (IMPDH) inhibitors. Bioorg Med Chem Lett 2020; 30:127543. [PMID: 32931912 DOI: 10.1016/j.bmcl.2020.127543] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/03/2020] [Accepted: 09/04/2020] [Indexed: 11/28/2022]
Abstract
Inosine-5'-monophosphate dehydrogenase (IMPDH) is a potential target for microorganisms. However, identifying inhibitor design determinants for IMPDH orthologs continues to evolve. Herein, a series of mycophenolic anilide inhibitors of Cryptosporidium parvum and human IMPDHs are reported. Furthermore, molecular docking of 12 (e.g. SH-19; CpIMPDH Ki,app = 0.042 ± 0.015 µM, HsIMPDH2 Ki,app = 0.13 ± 0.05 µM) supports different binding modes with the two enzymes. For CpIMPDH the inhibitor extends into a pocket in an adjacent subunit. In contrast, docking suggests the inhibitor interacts with Ser276 in the NAD binding site in HsIMPDH2, as well as an adjacent pocket within the same subunit. These results provide further guidance for generating IMPDH inhibitors for enzymes found in an array of pathogenic microorganisms, including Mycobacterium tuberculosis.
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Affiliation(s)
- Seungheon Lee
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Health Building 2, Houston, TX 77204, USA
| | - Angela F Ku
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Health Building 2, Houston, TX 77204, USA; Department of Chemistry, University of Houston, Health Building 2, Houston, TX 77204, USA
| | - Mohana Rao Vippila
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Health Building 2, Houston, TX 77204, USA
| | - Yong Wang
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Health Building 2, Houston, TX 77204, USA
| | - Minjia Zhang
- Departments of Biology, 415 South St., Waltham, MA 02454, USA
| | - Xingyou Wang
- Departments of Biology, 415 South St., Waltham, MA 02454, USA
| | - Lizbeth Hedstrom
- Departments of Biology, 415 South St., Waltham, MA 02454, USA; Chemistry, Brandeis University, 415 South St., Waltham, MA 02454, USA
| | - Gregory D Cuny
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Health Building 2, Houston, TX 77204, USA.
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8
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Omolabi KF, Agoni C, Olotu FA, Soliman MES. Molecular Basis of P131 Cryptosporidial-IMPDH Selectivity-A Structural, Dynamical and Mechanistic Stance. Cell Biochem Biophys 2020; 79:11-24. [PMID: 33058015 DOI: 10.1007/s12013-020-00950-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2020] [Indexed: 01/10/2023]
Abstract
Cryptosporidiosis accounts for a surge in infant (<5 years) mortality and morbidity. To date, several drug discovery efforts have been put in place to develop effective therapeutic options against the causative parasite. Based on a recent report, P131 spares inosine monophosphate dehydrogenase (IMPDH) in a eukaryotic model (mouse IMPDH (mIMPDH)) while binding selectively to the NAD+ site in Cryptosporidium parvum (CpIMPDH). However, no structural detail exists on the underlining mechanisms of P131-CpIMPDH selective targeting till date. To this effect, we investigate the selective inhibitory dynamics of P131 in CpIMPDH relative to mIMPDH via molecular biocomputation methods. Pairwise sequence alignment revealed prominent variations at the NAD+ binding regions of both proteins that accounted for disparate P131 binding activities. The influence of these variations was further revealed by the MM/PBSA energy estimations coupled with per-residue energy decomposition which monitored the systematic binding of the compound. Furthermore, relative high-affinity interactions occurred at the CpIMPDH NAD+ site which were majorly mediated by SER22, VAL24, PRO26, SER354, GLY357, and TYR358 located on chain D. These residues are unique to the parasite IMPDH form and not in the eukaryotic protein, highlighting variations that account for preferential P131 binding. Molecular insights provided herein corroborate previous experimental reports and further underpin the basis of CpIMPDH inhibitor selectivity. Findings from this study could present attractive prospects toward the design of novel anticryptosporidials with improved selectivity and binding affinity against parasitic targets.
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Affiliation(s)
- Kehinde F Omolabi
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban, 4001, South Africa
| | - Clement Agoni
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban, 4001, South Africa
| | - Fisayo A Olotu
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban, 4001, South Africa
| | - Mahmoud E S Soliman
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban, 4001, South Africa.
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Love MS, McNamara CW. Phenotypic screening techniques for Cryptosporidium drug discovery. Expert Opin Drug Discov 2020; 16:59-74. [PMID: 32892652 DOI: 10.1080/17460441.2020.1812577] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Introduction: Two landmark epidemiological studies identified Cryptosporidium spp. as a significant cause of diarrheal disease in pediatric populations in resource-limited countries. Notably, nitazoxanide is the only approved drug for treatment of cryptosporidiosis but shows limited efficacy. As a result, many drug discovery efforts have commenced to find improved treatments. The unique biology of Cryptosporidium presents challenges for traditional drug discovery methods, which has inspired new assay platforms to study parasite biology and drug screening. Areas covered: The authors review historical advancements in phenotypic-based assays and techniques for Cryptosporidium drug discovery, as well as recent advances that will define future drug discovery. The reliance on phenotypic-based screens and repositioning of phenotypic hits from other pathogens has quickly created a robust pipeline of potential cryptosporidiosis therapeutics. The latest advances involve new in vitro culture methods for oocyst generation, continuous culturing capabilities, and more physiologically relevant assays for testing compounds. Expert opinion: Previous phenotypic screening techniques have laid the groundwork for recent cryptosporidiosis drug discovery efforts. The resulting improved methodologies characterize compound activity, identify, and validate drug targets, and prioritize new compounds for drug development. The most recent improvements in phenotypic assays are poised to help advance compounds into clinical development.
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Affiliation(s)
- Melissa S Love
- Calibr, a division of The Scripps Research Institute , La Jolla, CA, USA
| | - Case W McNamara
- Calibr, a division of The Scripps Research Institute , La Jolla, CA, USA
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10
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Li Y, Liu M, Rizk MA, Moumouni PFA, Lee SH, Galon EM, Guo H, Gao Y, Li J, Beshbishy AM, Nugraha AB, Ji S, Tumwebaze MA, Benedicto B, Yokoyama N, Igarashi I, Xuan X. Drug screening of food and drug administration-approved compounds against Babesia bovis in vitro. Exp Parasitol 2020; 210:107831. [PMID: 31926147 DOI: 10.1016/j.exppara.2020.107831] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 12/03/2019] [Accepted: 01/04/2020] [Indexed: 10/25/2022]
Abstract
Babesia (B.) bovis is one of the main etiological agents of bovine babesiosis, causes serious economic losses to the cattle industry. Control of bovine babesiosis has been hindered by the limited treatment selection for B. bovis, thus, new options are urgently needed. We explored the drug library and unbiasedly screened 640 food and drug administration (FDA) approved drug compounds for their inhibitory activities against B. bovis in vitro. The initial screening identified 13 potentially effective compounds. Four potent compounds, namely mycophenolic acid (MPA), pentamidine (PTD), doxorubicin hydrochloride (DBH) and vorinostat (SAHA) exhibited the lowest IC50 and then selected for further evaluation of their in vitro efficacies using viability, combination inhibitory and cytotoxicity assays. The half-maximal inhibitory concentration (IC50) values of MPA, PTD, DBH, SAHA were 11.38 ± 1.66, 13.12 ± 4.29, 1.79 ± 0.15 and 45.18 ± 7.37 μM, respectively. Of note, DBH exhibited IC50 lower than that calculated for the commonly used antibabesial drug, diminazene aceturate (DA). The viability result revealed the ability of MPA, PTD, DBH, SAHA to prevent the regrowth of treated parasite at 4 × and 2 × of IC50. Antagonistic interactions against B. bovis were observed after treatment with either MPA, PTD, DBH or SAHA in combination with DA. Our findings indicate the richness of FDA approved compounds by novel potent antibabesial candidates and the identified potent compounds especially DBH might be used for the treatment of animal babesiosis caused by B. bovis.
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Affiliation(s)
- Yongchang Li
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan
| | - Mingming Liu
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan
| | - Mohamed Abdo Rizk
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan; Department of Internal Medicine and Infectious Diseases, Faculty of Veterinary Medicine, Mansoura University, 35516, Egypt
| | - Paul Franck Adjou Moumouni
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan
| | - Seung-Hun Lee
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan; College of Veterinary Medicine, Chungbuk National University, Cheongju, 28644, South Korea
| | - Eloiza May Galon
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan
| | - Huanping Guo
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan
| | - Yang Gao
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan
| | - Jixu Li
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan
| | - Amani Magdy Beshbishy
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan
| | - Arifin Budiman Nugraha
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan; Faculty of Veterinary Medicine, Bogor Agricultural University, Jl. Agatis Kampus IPB Dramaga, Bogor, 16680, Indonesia
| | - Shengwei Ji
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan
| | - Maria Agnes Tumwebaze
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan
| | - Byamukama Benedicto
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan
| | - Naoaki Yokoyama
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan
| | - Ikuo Igarashi
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan
| | - Xuenan Xuan
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Hokkaido, Japan.
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Pawlowic MC, Somepalli M, Sateriale A, Herbert GT, Gibson AR, Cuny GD, Hedstrom L, Striepen B. Genetic ablation of purine salvage in Cryptosporidium parvum reveals nucleotide uptake from the host cell. Proc Natl Acad Sci U S A 2019; 116:21160-21165. [PMID: 31570573 PMCID: PMC6800313 DOI: 10.1073/pnas.1908239116] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The apicomplexan parasite Cryptosporidium is a leading global cause of severe diarrheal disease and an important contributor to early-childhood mortality. Waterborne outbreaks occur frequently, even in countries with advanced water treatment capabilities, and there is currently no fully effective treatment. Nucleotide pathways are attractive targets for antimicrobial development, and several laboratories are designing inhibitors of these enzymes as potential treatment for Cryptosporidium infections. Here we take advantage of newly available molecular genetics for Cryptosporidium parvum to investigate nucleotide biosynthesis by directed gene ablation. Surprisingly, we found that the parasite tolerates the loss of classical targets including dihydrofolate reductase-thymidylate synthase (DHFR-TS) and inosine monophosphate dehydrogenase (IMPDH). We show that thymidine kinase provides a route to thymidine monophosphate in the absence of DHFR-TS. In contrast, only a single pathway has been identified for C. parvum purine nucleotide salvage. Nonetheless, multiple enzymes in the purine pathway, as well as the adenosine transporter, can be ablated. The resulting mutants are viable under normal conditions but are hypersensitive to inhibition of purine nucleotide synthesis in their host cell. Cryptosporidium might use as-yet undiscovered purine transporters and salvage enzymes; however, genetic and pharmacological experiments led us to conclude that Cryptosporidium imports purine nucleotides from the host cell. The potential for ATP uptake from the host has significant impact on our understanding of parasite energy metabolism given that Cryptosporidium lacks oxidative phosphorylation and glycolytic enzymes are not constitutively expressed throughout the parasite life cycle.
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Affiliation(s)
- Mattie C Pawlowic
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| | - Mastanbabu Somepalli
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Adam Sateriale
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Gillian T Herbert
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| | - Alexis R Gibson
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Gregory D Cuny
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204
| | - Lizbeth Hedstrom
- Department of Biology, Brandeis University, Waltham, MA 02454
- Department of Chemistry, Brandeis University, Waltham, MA 02454
| | - Boris Striepen
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602;
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
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12
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Zhang M, Yan H, Lu M, Wang D, Sun S. Antifungal activity of ribavirin used alone or in combination with fluconazole against Candida albicans is mediated by reduced virulence. Int J Antimicrob Agents 2019; 55:105804. [PMID: 31605727 DOI: 10.1016/j.ijantimicag.2019.09.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 09/07/2019] [Accepted: 09/11/2019] [Indexed: 01/01/2023]
Abstract
The incidence of fungal infections has increased continuously in recent years, and drug resistance, especially resistance to fluconazole (FLC), has emerged. To overcome this challenge, research on the antifungal activities of non-antifungal agents has gained more attention. In this study, we determined the anti-Candida activity of ribavirin (RBV), an antiviral drug commonly used in the clinic, and found that RBV displayed potent antifungal activity when used alone or in combination with FLC in vitro and in vivo. In vitro, the MIC80 values of RBV were 2-4 µg/mL for FLC-susceptible Candida albicans and 8 µg/mL for FLC-resistant C. albicans. When RBV at a dose of 1 µg/mL was combined with FLC, significant synergistic effects were exhibited against FLC-resistant C. albicans, and the MICs of FLC decreased from >512 µg/mL to 0.25-1 µg/mL. Synergism was also exhibited against C. albicans biofilms. In vivo, RBV plus FLC significantly improved the survival of infected Galleria mellonella larvae compared with the FLC-treated group over a 4-day period and attenuated the damage of FLC-resistant C. albicans to G. mellonella larvae tissue. Furthermore, mechanistic studies indicated that the antifungal effects of RBV used alone or in combination with FLC might be associated with inhibition of biofilm formation, reduced extracellular phospholipase activity and inhibition of hyphal growth, but is not related to promotion of FLC uptake and inhibition of FLC efflux. These results provide a promising direction for overcoming drug resistance and for expanding the clinical application of existing drugs.
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Affiliation(s)
- Min Zhang
- School of Pharmaceutical Sciences, Shandong First Medical University, Tai'an, Shandong Province, China; Department of Pharmacy, Tai'an Municipal Hospital, Tai'an, Shandong Province, China
| | - Haiying Yan
- Department of Pharmacy, Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, Shandong Province, China
| | - Mengjiao Lu
- Department of Pharmacy, Tianjin Baodi Hospital, Baodi Clinical College of Tianjin Medical University, Tianjin, China
| | - Decai Wang
- School of Pharmaceutical Sciences, Shandong First Medical University, Tai'an, Shandong Province, China
| | - Shujuan Sun
- Department of Pharmacy, Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, Shandong Province, China.
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13
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Novel adenosine-derived inhibitors of Cryptosporidium parvum inosine 5'-monophosphate dehydrogenase. J Antibiot (Tokyo) 2019; 72:934-942. [PMID: 31296916 DOI: 10.1038/s41429-019-0199-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/22/2019] [Accepted: 05/27/2019] [Indexed: 11/08/2022]
Abstract
We have found cyclophane-type adenosine derivatives having p-quinone amide moieties (1 and 2) as weak inhibitors of Cryptosporidium parvum inosine 5'-monophosphate dehydrogenase (CpIMPDH) from the Hokkaido University Chemical Library via the luciferase-based high-throughput screening. To obtain more potent inhibitors, we synthesized four new derivatives free from cyclophane rings (3-6). The N-H derivatives 3 and 5 showed more potent activities (24.4 and 11.1 μM, respectively) in the presence of dithiothreitol (DTT), whereas the N-methyl derivative 4 indicated more potent activity (2.1 μM) without DTT. Conformational analysis of compounds 3 and 4 suggested that N-H amide 3 binds to IMP-binding site in the DTT mediated manner.
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Yang L, Ru Y, Cai X, Yin Z, Liu X, Xiao Y, Zhang H, Zheng X, Wang P, Zhang Z. MoImd4 mediates crosstalk between MoPdeH-cAMP signalling and purine metabolism to govern growth and pathogenicity in Magnaporthe oryzae. MOLECULAR PLANT PATHOLOGY 2019; 20:500-518. [PMID: 30426699 PMCID: PMC6422694 DOI: 10.1111/mpp.12770] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The high-affinity cyclic adenosine monophosphate (cAMP) phosphodiesterase MoPdeH is important not only for cAMP signalling and pathogenicity, but also for cell wall integrity (CWI) maintenance in the rice blast fungus Magnaporthe oryzae. To explore the underlying mechanism, we identified MoImd4 as an inosine-5'-monophosphate dehydrogenase (IMPDH) homologue that interacts with MoPdeH. Targeted deletion of MoIMD4 resulted in reduced de novo purine biosynthesis and growth, as well as attenuated pathogenicity, which were suppressed by exogenous xanthosine monophosphate (XMP). Treatment with mycophenolic acid (MPA), which specifically inhibits MoImd4 activity, resulted in reduced growth and virulence attenuation. Intriguingly, further analysis showed that MoImd4 promotes the phosphodiesterase activity of MoPdeH, thereby decreasing intracellular cAMP levels, and MoPdeH also promotes the IMPDH activity of MoImd4. Our studies revealed the presence of a novel crosstalk between cAMP regulation and purine biosynthesis in M. oryzae, and indicated that such a link is also important in the pathogenesis of M. oryzae.
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Affiliation(s)
- Lina Yang
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of EducationNanjing210095China
| | - Yanyan Ru
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of EducationNanjing210095China
| | - Xingjia Cai
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of EducationNanjing210095China
| | - Ziyi Yin
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of EducationNanjing210095China
| | - Xinyu Liu
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of EducationNanjing210095China
| | - Yuhan Xiao
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of EducationNanjing210095China
| | - Haifeng Zhang
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of EducationNanjing210095China
| | - Xiaobo Zheng
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of EducationNanjing210095China
| | - Ping Wang
- Departments of Pediatrics, and Microbiology, Immunology, and ParasitologyLouisiana State University Health Sciences CenterNew OrleansLA70112USA
| | - Zhengguang Zhang
- Department of Plant Pathology, College of Plant ProtectionNanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of EducationNanjing210095China
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Yu R, Kim Y, Maltseva N, Braunstein P, Joachimiak A, Hedstrom L. Oxanosine Monophosphate Is a Covalent Inhibitor of Inosine 5'-Monophosphate Dehydrogenase. Chem Res Toxicol 2019; 32:456-466. [PMID: 30746940 DOI: 10.1021/acs.chemrestox.8b00342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reactive nitrogen species (RNS) are produced during infection and inflammation, and the effects of these agents on proteins, DNA, and lipids are well recognized. In contrast, the effects of RNS damaged metabolites are less appreciated. 5-Amino-3-β-(d-ribofuranosyl)-3 H-imidazo-[4,5- d][1,3]oxazine-7-one (oxanosine) and its nucleotides are products of guanosine nitrosation. Here we demonstrate that oxanosine monophosphate (OxMP) is a potent reversible competitive inhibitor of IMPDH. The value of Ki varies from 50 to 340 nM among IMPDHs from five different organisms. UV spectroscopy and X-ray crystallography indicate that OxMP forms a ring-opened covalent adduct with the active site Cys (E-OxMP*). Unlike the covalent intermediate of the normal catalytic reaction, E-OxMP* does not hydrolyze, but instead recyclizes to OxMP. IMPDH inhibitors block proliferation and can induce apoptosis, so the inhibition of IMPDH by OxMP presents another potential mechanism for RNS toxicity.
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Affiliation(s)
- Runhan Yu
- Department of Chemistry , Brandeis University , Waltham , Massachusetts 02454 , United States
| | - Youngchang Kim
- Structural Biology Center, Biosciences , Argonne National Laboratory , Argonne , Illinois 60439 , United States.,Center for Structural Genomics of Infectious Diseases, Consortium for Advanced Science and Engineering , University of Chicago , Chicago , Illinois 60637 , United States
| | - Natalia Maltseva
- Center for Structural Genomics of Infectious Diseases, Consortium for Advanced Science and Engineering , University of Chicago , Chicago , Illinois 60637 , United States
| | - Philip Braunstein
- Department of Biochemistry , Brandeis University , Waltham , Massachusetts 02454 , United States
| | - Andrzej Joachimiak
- Structural Biology Center, Biosciences , Argonne National Laboratory , Argonne , Illinois 60439 , United States.,Center for Structural Genomics of Infectious Diseases, Consortium for Advanced Science and Engineering , University of Chicago , Chicago , Illinois 60637 , United States.,Department of Biochemistry and Molecular Biology , University of Chicago , Chicago , Illinois 60557 , United States
| | - Lizbeth Hedstrom
- Department of Chemistry , Brandeis University , Waltham , Massachusetts 02454 , United States.,Department of Biology , Brandeis University , Waltham , Massachusetts 02454 , United States
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Sarwono AEY, Mitsuhashi S, Kabir MHB, Shigetomi K, Okada T, Ohsaka F, Otsuguro S, Maenaka K, Igarashi M, Kato K, Ubukata M. Repurposing existing drugs: identification of irreversible IMPDH inhibitors by high-throughput screening. J Enzyme Inhib Med Chem 2018; 34:171-178. [PMID: 30451014 PMCID: PMC6249553 DOI: 10.1080/14756366.2018.1540474] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Inosine 5'-monophosphate dehydrogenase (IMPDH) is an essential enzyme for the production of guanine nucleotides. Disruption of IMPDH activity has been explored as a therapeutic strategy for numerous purposes, such as for anticancer, immunosuppression, antiviral, and antimicrobial therapy. In the present study, we established a luciferase-based high-throughput screening system to identify IMPDH inhibitors from our chemical library of known bioactive small molecules. The screening of 1400 compounds resulted in the discovery of three irreversible inhibitors: disulfiram, bronopol, and ebselen. Each compound has a distinct chemical moiety that differs from other reported IMPDH inhibitors. Further evaluation revealed that these compounds are potent inhibitors of IMPDHs with kon values of 0.7 × 104 to 9.3 × 104 M-1·s-1. Both disulfiram and bronopol exerted similar degree of inhibition to protozoan and mammalian IMPDHs. Ebselen showed an intriguing difference in mode of inhibition for different IMPDHs, with reversible and irreversible inhibition to each Cryptosporidium parvum IMPDH and human IMPDH type II, respectively. In the preliminary efficacy experiment against cryptosporidiosis in severe combined immunodeficiency (SCID) mouse, a decrease in the number of oocyst shed was observed upon the oral administration of disulfiram and bronopol, providing an early clinical proof-of-concept for further utilization of these compounds as IMPDH inhibitors.
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Affiliation(s)
| | - Shinya Mitsuhashi
- a Division of Applied Bioscience, Graduate School of Agriculture , Hokkaido University , Sapporo , Japan.,b Department of Cellular and Molecular Biology , The University of Texas Health Science Center at Tyler , Tyler , TX , USA
| | - Mohammad Hazzaz Bin Kabir
- c National Research Center for Protozoan Diseases , Obihiro University of Agriculture and Veterinary Medicine , Obihiro , Japan
| | - Kengo Shigetomi
- a Division of Applied Bioscience, Graduate School of Agriculture , Hokkaido University , Sapporo , Japan
| | - Tadashi Okada
- c National Research Center for Protozoan Diseases , Obihiro University of Agriculture and Veterinary Medicine , Obihiro , Japan.,e Division of Neurology, Respirology and Metabolism, Department of Internal Medicine, Faculty of Medicine , University of Miyazaki , Kiyotake , Miyazaki, Japan
| | - Fumina Ohsaka
- d Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences , Hokkaido University , Sapporo , Japan
| | - Satoko Otsuguro
- d Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences , Hokkaido University , Sapporo , Japan
| | - Katsumi Maenaka
- d Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences , Hokkaido University , Sapporo , Japan
| | - Makoto Igarashi
- c National Research Center for Protozoan Diseases , Obihiro University of Agriculture and Veterinary Medicine , Obihiro , Japan
| | - Kentaro Kato
- c National Research Center for Protozoan Diseases , Obihiro University of Agriculture and Veterinary Medicine , Obihiro , Japan
| | - Makoto Ubukata
- a Division of Applied Bioscience, Graduate School of Agriculture , Hokkaido University , Sapporo , Japan
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Khan A, Shaik JS, Grigg ME. Genomics and molecular epidemiology of Cryptosporidium species. Acta Trop 2018; 184:1-14. [PMID: 29111140 DOI: 10.1016/j.actatropica.2017.10.023] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 10/20/2017] [Accepted: 10/26/2017] [Indexed: 11/16/2022]
Abstract
Cryptosporidium is one of the most widespread protozoan parasites that infects domestic and wild animals and is considered the second major cause of diarrhea and death in children after rotavirus. So far, around 20 distinct species are known to cause severe to moderate infections in humans, of which Cryptosporidium hominis and Cryptosporidium parvum are the major causative agents. Currently, ssurRNA and gp60 are used as the optimal markers for differentiating species and subtypes respectively. Over the last decade, diagnostic tools to detect and differentiate Cryptosporidium species at the genotype and subtype level have improved, but our understanding of the zoonotic and anthroponotic transmission potential of each species is less clear, largely because of the paucity of high resolution whole genome sequencing data for the different species. Defining which species possess an anthroponotic vs. zoonotic transmission cycle is critical if we are to limit the spread of disease between animals and humans. Likewise, it is unclear to what extent genetic hybridization impacts disease potential or the emergence of outbreak strains. The development of high resolution genetic markers and whole genome sequencing of different species should provide new insights into these knowledge gaps. The aim of this review is to outline currently available molecular epidemiology and genomics data for different species of Cryptosporidium.
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Affiliation(s)
- Asis Khan
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
| | - Jahangheer S Shaik
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Michael E Grigg
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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18
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Sarwono AEY, Suganuma K, Mitsuhashi S, Okada T, Musinguzi SP, Shigetomi K, Inoue N, Ubukata M. Identification and characterization of guanosine 5'-monophosphate reductase of Trypanosoma congolense as a drug target. Parasitol Int 2017; 66:537-544. [PMID: 28366788 DOI: 10.1016/j.parint.2017.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 02/17/2017] [Accepted: 03/27/2017] [Indexed: 10/19/2022]
Abstract
Trypanosoma congolense is one of the most prevalent pathogens which causes trypanosomosis in African animals, resulting in a significant economic loss. In its life cycle, T. congolense is incapable of synthesizing purine nucleotides via a de novo pathway, and thus relies on a salvage pathway to survive. In this study, we identified a gene from T. congolense, TcIL3000_5_1940, as a guanosine 5'-monophosphate reductase (GMPR), an enzyme that modulates the concentration of intracellular guanosine in the pathogen. The recombinant protein was expressed in Escherichia coli, and the gene product was enzymatically confirmed as a unique GMPR, designated as rTcGMPR. This enzyme was constitutively expressed in glycosomes at all of the parasite's developmental stages similar to other purine nucleotide metabolic enzymes. Mycophenolic acid (MPA) was found to inhibit rTcGMPR activity. Hence, it is a potential lead compound for the design of trypanocidal agents, specifically GMPR inhibitor.
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Affiliation(s)
- Albertus Eka Yudistira Sarwono
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-8589, Japan
| | - Keisuke Suganuma
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan; Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Shinya Mitsuhashi
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-8589, Japan
| | - Tadashi Okada
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan; Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Simon Peter Musinguzi
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Kengo Shigetomi
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-8589, Japan
| | - Noboru Inoue
- Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Makoto Ubukata
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
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19
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Mycophenolic Acid and Its Derivatives as Potential Chemotherapeutic Agents Targeting Inosine Monophosphate Dehydrogenase in Trypanosoma congolense. Antimicrob Agents Chemother 2016; 60:4391-3. [PMID: 27139487 DOI: 10.1128/aac.02816-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 04/27/2016] [Indexed: 01/23/2023] Open
Abstract
This study aimed to evaluate the trypanocidal activity of mycophenolic acid (MPA) and its derivatives for Trypanosoma congolense The proliferation of T. congolense was completely inhibited by adding <1 μM MPA and its derivatives. In addition, the IMP dehydrogenase in T. congolense was molecularly characterized as the target of these compounds. The results suggest that MPA and its derivatives have the potential to be new candidates as novel trypanocidal drugs.
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20
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Smith S, Boitz J, Chidambaram ES, Chatterjee A, Ait-Tihyaty M, Ullman B, Jardim A. The cystathionine-β-synthase domains on the guanosine 5''-monophosphate reductase and inosine 5'-monophosphate dehydrogenase enzymes from Leishmania regulate enzymatic activity in response to guanylate and adenylate nucleotide levels. Mol Microbiol 2016; 100:824-40. [PMID: 26853689 DOI: 10.1111/mmi.13352] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/07/2016] [Indexed: 01/24/2023]
Abstract
The Leishmania guanosine 5'-monophosphate reductase (GMPR) and inosine 5'-monophosphate dehydrogenase (IMPDH) are purine metabolic enzymes that function maintaining the cellular adenylate and guanylate nucleotide. Interestingly, both enzymes contain a cystathionine-β-synthase domain (CBS). To investigate this metabolic regulation, the Leishmania GMPR was cloned and shown to be sufficient to complement the guaC (GMPR), but not the guaB (IMPDH), mutation in Escherichia coli. Kinetic studies confirmed that the Leishmania GMPR catalyzed a strict NADPH-dependent reductive deamination of GMP to produce IMP. Addition of GTP or high levels of GMP induced a marked increase in activity without altering the Km values for the substrates. In contrast, the binding of ATP decreased the GMPR activity and increased the GMP Km value 10-fold. These kinetic changes were correlated with changes in the GMPR quaternary structure, induced by the binding of GMP, GTP, or ATP to the GMPR CBS domain. The capacity of these CBS domains to mediate the catalytic activity of the IMPDH and GMPR provides a regulatory mechanism for balancing the intracellular adenylate and guanylate pools.
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Affiliation(s)
- Sabrina Smith
- Institute of Parasitology and Centre for Host-Parasite Interactions, Macdonald Campus of McGill University, 21 111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
| | - Jan Boitz
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Ehzilan Subramanian Chidambaram
- Institute of Parasitology and Centre for Host-Parasite Interactions, Macdonald Campus of McGill University, 21 111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
| | - Abhishek Chatterjee
- Institute of Parasitology and Centre for Host-Parasite Interactions, Macdonald Campus of McGill University, 21 111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
| | - Maria Ait-Tihyaty
- Institute of Parasitology and Centre for Host-Parasite Interactions, Macdonald Campus of McGill University, 21 111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
| | - Buddy Ullman
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Armando Jardim
- Institute of Parasitology and Centre for Host-Parasite Interactions, Macdonald Campus of McGill University, 21 111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
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21
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Miyamoto Y, Eckmann L. Drug Development Against the Major Diarrhea-Causing Parasites of the Small Intestine, Cryptosporidium and Giardia. Front Microbiol 2015; 6:1208. [PMID: 26635732 PMCID: PMC4652082 DOI: 10.3389/fmicb.2015.01208] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 10/16/2015] [Indexed: 12/23/2022] Open
Abstract
Diarrheal diseases are among the leading causes of morbidity and mortality in the world, particularly among young children. A limited number of infectious agents account for most of these illnesses, raising the hope that advances in the treatment and prevention of these infections can have global health impact. The two most important parasitic causes of diarrheal disease are Cryptosporidium and Giardia. Both parasites infect predominantly the small intestine and colonize the lumen and epithelial surface, but do not invade deeper mucosal layers. This review discusses the therapeutic challenges, current treatment options, and drug development efforts against cryptosporidiosis and giardiasis. The goals of drug development against Cryptosporidium and Giardia are different. For Cryptosporidium, only one moderately effective drug (nitazoxanide) is available, so novel classes of more effective drugs are a high priority. Furthermore, new genetic technology to identify potential drug targets and better assays for functional evaluation of these targets throughout the parasite life cycle are needed for advancing anticryptosporidial drug design. By comparison, for Giardia, several classes of drugs with good efficacy exist, but dosing regimens are suboptimal and emerging resistance begins to threaten clinical utility. Consequently, improvements in potency and dosing, and the ability to overcome existing and prevent new forms of drug resistance are priorities in antigiardial drug development. Current work on new drugs against both infections has revealed promising strategies and new drug leads. However, the primary challenge for further drug development is the underlying economics, as both parasitic infections are considered Neglected Diseases with low funding priority and limited commercial interest. If a new urgency in medical progress against these infections can be raised at national funding agencies or philanthropic organizations, meaningful and timely progress is possible in treating and possibly preventing cryptosporidiosis and giardiasis.
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Affiliation(s)
- Yukiko Miyamoto
- Department of Medicine, University of California at San Diego, La Jolla CA, USA
| | - Lars Eckmann
- Department of Medicine, University of California at San Diego, La Jolla CA, USA
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Li RJ, Wang YL, Wang QH, Huang WX, Wang J, Cheng MS. Binding mode of inhibitors and Cryptosporidium parvum IMP dehydrogenase: A combined ligand- and receptor-based study. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2015; 26:421-438. [PMID: 25978645 DOI: 10.1080/1062936x.2015.1043341] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A combined ligand- and target-based approach was used to analyse the interaction models of Cryptosporidium parvum inosine 5'-monophosphate dehydrogenase (CpIMPDH) with selective inhibitors. First, a ligand-based pharmacophore model was generated from 20 NAD(+) competitive CpIMPDH inhibitors with the HipHop module. The characteristic of the NAD(+) binding site of CpIMPDH was then described, and the binding modes of the representative inhibitors were studied by molecular docking. The combination of the pharmacophore model and the docking results allowed us to evaluate the pharmacophore features and structural information of the NAD(+) binding site of CpIMPDH. This research supports the proposal of an interaction model inside the NAD(+) binding site of CpIMPDH, consisting of four key interaction points: two hydrophobic-aromatic groups, a hydrophobic-aliphatic group and a hydrogen bond donor. This study also provides guidance for the design of more potent CpIMPDH inhibitors for the treatment of Cryptosporidium infections.
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Affiliation(s)
- R-J Li
- a Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education , Shenyang Pharmaceutical University , Shenyang , China
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23
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Ryan U, Hijjawi N. New developments in Cryptosporidium research. Int J Parasitol 2015; 45:367-73. [DOI: 10.1016/j.ijpara.2015.01.009] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 12/24/2022]
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Kim Y, Makowska-Grzyska M, Gorla SK, Gollapalli DR, Cuny GD, Joachimiak A, Hedstrom L. Structure of Cryptosporidium IMP dehydrogenase bound to an inhibitor with in vivo antiparasitic activity. Acta Crystallogr F Struct Biol Commun 2015; 71:531-8. [PMID: 25945705 PMCID: PMC4427161 DOI: 10.1107/s2053230x15000187] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 01/06/2015] [Indexed: 11/10/2022] Open
Abstract
Inosine 5'-monophosphate dehydrogenase (IMPDH) is a promising target for the treatment of Cryptosporidium infections. Here, the structure of C. parvum IMPDH (CpIMPDH) in complex with inosine 5'-monophosphate (IMP) and P131, an inhibitor with in vivo anticryptosporidial activity, is reported. P131 contains two aromatic groups, one of which interacts with the hypoxanthine ring of IMP, while the second interacts with the aromatic ring of a tyrosine in the adjacent subunit. In addition, the amine and NO2 moieties bind in hydrated cavities, forming water-mediated hydrogen bonds to the protein. The design of compounds to replace these water molecules is a new strategy for the further optimization of C. parvum inhibitors for both antiparasitic and antibacterial applications.
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Affiliation(s)
- Youngchang Kim
- Center for Structural Genomics of Infectious Diseases, Computational Institute, University of Chicago, 5735 S. Ellis Avenue, Chicago, IL 60637, USA
- Structural Biology Center, Biosciences, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439, USA
| | - Magdalena Makowska-Grzyska
- Center for Structural Genomics of Infectious Diseases, Computational Institute, University of Chicago, 5735 S. Ellis Avenue, Chicago, IL 60637, USA
| | - Suresh Kumar Gorla
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA
| | | | - Gregory D. Cuny
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Science and Research Building 2, Houston, TX 77204, USA
| | - Andrzej Joachimiak
- Center for Structural Genomics of Infectious Diseases, Computational Institute, University of Chicago, 5735 S. Ellis Avenue, Chicago, IL 60637, USA
- Structural Biology Center, Biosciences, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439, USA
| | - Lizbeth Hedstrom
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA 02454, USA
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25
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Sun Z, Khan J, Makowska-Grzyska M, Zhang M, Cho JH, Suebsuwong C, Vo P, Gollapalli DR, Kim Y, Joachimiak A, Hedstrom L, Cuny GD. Synthesis, in vitro evaluation and cocrystal structure of 4-oxo-[1]benzopyrano[4,3-c]pyrazole Cryptosporidium parvum inosine 5'-monophosphate dehydrogenase (CpIMPDH) inhibitors. J Med Chem 2014; 57:10544-50. [PMID: 25474504 PMCID: PMC4281095 DOI: 10.1021/jm501527z] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Cryptosporidium inosine 5′-monophosphate
dehydrogenase (CpIMPDH) has emerged as a therapeutic
target for treating Cryptosporidium parasites because it catalyzes a critical step in guanine nucleotide
biosynthesis. A 4-oxo-[1]benzopyrano[4,3-c]pyrazole
derivative was identified as a moderately potent (IC50 =
1.5 μM) inhibitor of CpIMPDH. We report a SAR
study for this compound series resulting in 8k (IC50 = 20 ± 4 nM). In addition, an X-ray crystal structure
of CpIMPDH·IMP·8k is also
presented.
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Affiliation(s)
- Zhuming Sun
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston , Science and Research Building 2, Room 549A, Houston, Texas 77204, United States
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Jefferies R, Yang R, Woh CK, Weldt T, Milech N, Estcourt A, Armstrong T, Hopkins R, Watt P, Reid S, Armson A, Ryan UM. Target validation of the inosine monophosphate dehydrogenase (IMPDH) gene in Cryptosporidium using Phylomer(®) peptides. Exp Parasitol 2014; 148:40-8. [PMID: 25447124 DOI: 10.1016/j.exppara.2014.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 11/07/2014] [Indexed: 01/03/2023]
Abstract
Cryptosporidiosis, a gastroenteric disease characterised mainly by diarrheal illnesses in humans and mammals is caused by infection with the protozoan parasite Cryptosporidium. Treatment options for cryptosporidiosis are limited, with the current therapeutic nitazoxanide, only partly efficacious in immunocompetent individuals. The parasite lacks de novo purine synthesis, and is exclusively dependant on purine salvage from its host. Inhibition of the inosine 5' monophosphate dehydrogenase (IMPDH), a purine salvage enzyme that is essential for DNA synthesis, thereby offers a potential drug target against this parasite. In the present study, a yeast-two-hybrid system was used to identify Phylomer peptides within a library constructed from the genomes of 25 phylogenetically diverse bacteria that targeted the IMPDH of Cryptosporidium parvum (IMPcp) and Cryptosporidium hominis (IMPch). We identified 38 unique interacting Phylomers, of which, 12 were synthesised and screened against C. parvum in vitro. Two Phylomers exhibited significant growth inhibition (81.2-83.8% inhibition; P < 0.05), one of which consistently exhibited positive interactions with IMPcp and IMPch during primary and recapitulation yeast two-hybrid screening and did not interact with either of the human IMPDH proteins. The present study highlightsthe potential of Phylomer peptides as target validation tools for Cryptosporidium and other organisms and diseases because of their ability to bind with high affinity to target proteins and disrupt function.
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Affiliation(s)
- R Jefferies
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia; Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - R Yang
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - C K Woh
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia; Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - T Weldt
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - N Milech
- Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - A Estcourt
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - T Armstrong
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - R Hopkins
- Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - P Watt
- Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - S Reid
- School of Population Health, The University of Queensland, Herston, Queensland, Australia
| | - A Armson
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - U M Ryan
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia.
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Abstract
SUMMARYCryptosporidiumhost cell interaction remains fairly obscure compared with other apicomplexans such asPlasmodiumorToxoplasma. The reason for this is probably the inability of this parasite to complete its life cyclein vitroand the lack of a system to genetically modifyCryptosporidium. However, there is a substantial set of data about the molecules involved in attachment and invasion and about the host cell pathways involved in actin arrangement that are altered by the parasite. Here we summarize the recent advances in research on host cell infection regarding the excystation process, attachment and invasion, survival in the cell, egress and the available data on omics.
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Cao S, Aboge GO, Terkawi MA, Zhou M, Kamyingkird K, Moumouni PFA, Masatani T, Igarashi I, Nishikawa Y, Suzuki H, Xuan X. Mycophenolic acid, mycophenolate mofetil, mizoribine, ribavirin, and 7-nitroindole inhibit propagation of Babesia parasites by targeting inosine 5'-monophosphate dehydrogenase. J Parasitol 2014; 100:522-6. [PMID: 24580148 DOI: 10.1645/13-278.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The resistance of Babesia parasites to current anti-babesiosis drugs is an issue of major concern. The inosine 5'-monophosphate dehydrogenase (IMPDH) of Babesia gibsoni has been identified and characterized as a molecular drug target in our previous studies. In the present study, inhibitory effects of IMPDH inhibitors (mycophenolate mofetil, mizoribine, ribavirin, 7-nitroindole, and mycophenolic acid) were evaluated in vitro or in vivo. In the inhibition assay of recombinant B. gibsoni IMPDH activity, mycophenolate mofetil was the most potent inhibitor (IC(50) = 2.58 ± 1.32 μM) while ribavirin was the least potent. The inhibitory effects of mycophenolate mofetil, mizoribine, ribavirin, and 7-nitroindole on the in vitro growths of B. gibsoni and Babesia bovis were also assessed. The results revealed that mycophenolate mofetil was the most potent inhibitor of the multiplications of both B. gibsoni (IC(50) = 0.13 ± 0.05 μM) and B. bovis (IC(50) = 0.97 ± 0.49 μM). Ribavirin was also the least potent for both B. gibsoni and B. bovis in vitro. Mycophenolic acid, a metabolite of mycophenolate mofetil, caused an inhibition of Babesia microti in mice with noticeable improvement in hematological parameters of the infected mice (ED(50) = 44.15 ± 12.53 mg/kg). Although the report provides a non-exhaustive view of potential treatment strategy without addressing the potential adverse effect of immune suppression on infections, these results indicated that the IMPDH might be a molecular target of MPA for B. microti . Altogether, we provide a basis for development of antibabesia prodrugs by targeting IMPDH of the parasites in the treatment of babesiosis.
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Affiliation(s)
- Shinuo Cao
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan
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Rostirolla DC, Milech de Assunção T, Bizarro CV, Basso LA, Santos DS. Biochemical characterization of Mycobacterium tuberculosis IMP dehydrogenase: kinetic mechanism, metal activation and evidence of a cooperative system. RSC Adv 2014. [DOI: 10.1039/c4ra02142h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Proposed kinetic mechanism forMtIMPDH in the presence of K+.
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Affiliation(s)
- Diana Carolina Rostirolla
- Centro de Pesquisas em Biologia Molecular e Funcional (CPBMF)
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB)
- Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS)
- Porto Alegre, Brazil
- Programa de Pós-Graduação em Medicina e Ciências da Saúde
| | | | - Cristiano Valim Bizarro
- Centro de Pesquisas em Biologia Molecular e Funcional (CPBMF)
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB)
- Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS)
- Porto Alegre, Brazil
| | - Luiz Augusto Basso
- Centro de Pesquisas em Biologia Molecular e Funcional (CPBMF)
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB)
- Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS)
- Porto Alegre, Brazil
- Programa de Pós-Graduação em Medicina e Ciências da Saúde
| | - Diogenes Santiago Santos
- Centro de Pesquisas em Biologia Molecular e Funcional (CPBMF)
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB)
- Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS)
- Porto Alegre, Brazil
- Programa de Pós-Graduação em Medicina e Ciências da Saúde
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Validation of IMP dehydrogenase inhibitors in a mouse model of cryptosporidiosis. Antimicrob Agents Chemother 2013; 58:1603-14. [PMID: 24366728 DOI: 10.1128/aac.02075-13] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Cryptosporidium parasites are a major cause of diarrhea and malnutrition in the developing world, a frequent cause of waterborne disease in the developed world, and a potential bioterrorism agent. Currently, available treatment is limited, and Cryptosporidium drug discovery remains largely unsuccessful. As a result, the pharmacokinetic properties required for in vivo efficacy have not been established. We have been engaged in a Cryptosporidium drug discovery program targeting IMP dehydrogenase (CpIMPDH). Here, we report the activity of eight potent and selective inhibitors of CpIMPDH in the interleukin-12 (IL-12) knockout mouse model, which mimics acute human cryptosporidiosis. Two compounds displayed significant antiparasitic activity, validating CpIMPDH as a drug target. The best compound, P131 (250 mg/kg of body weight/day), performed equivalently to paromomycin (2,000 mg/kg/day) when administered in a single dose and better than paromomycin when administered in three daily doses. One compound, A110, appeared to promote Cryptosporidium infection. The pharmacokinetic, uptake, and permeability properties of the eight compounds were measured. P131 had the lowest systemic distribution but accumulated to high concentrations within intestinal cells. A110 had the highest systemic distribution. These observations suggest that systemic distribution is not required, and may be a liability, for in vivo antiparasitic activity. Intriguingly, A110 caused specific alterations in fecal microbiota that were not observed with P131 or vehicle alone. Such changes may explain how A110 promotes parasitemia. Collectively, these observations suggest a blueprint for the development of anticryptosporidial therapy.
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Jex AR, Koehler AV, Ansell BR, Baker L, Karunajeewa H, Gasser RB. Getting to the guts of the matter: The status and potential of ‘omics’ research of parasitic protists of the human gastrointestinal system. Int J Parasitol 2013; 43:971-82. [DOI: 10.1016/j.ijpara.2013.06.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 06/07/2013] [Accepted: 06/07/2013] [Indexed: 11/17/2022]
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Gorla SK, Kavitha M, Zhang M, Chin JEW, Liu X, Striepen B, Makowska-Grzyska M, Kim Y, Joachimiak A, Hedstrom L, Cuny GD. Optimization of benzoxazole-based inhibitors of Cryptosporidium parvum inosine 5'-monophosphate dehydrogenase. J Med Chem 2013; 56:4028-43. [PMID: 23668331 DOI: 10.1021/jm400241j] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cryptosporidium parvum is an enteric protozoan parasite that has emerged as a major cause of diarrhea, malnutrition, and gastroenteritis and poses a potential bioterrorism threat. C. parvum synthesizes guanine nucleotides from host adenosine in a streamlined pathway that relies on inosine 5'-monophosphate dehydrogenase (IMPDH). We have previously identified several parasite-selective C. parvum IMPDH (CpIMPDH) inhibitors by high-throughput screening. In this paper, we report the structure-activity relationship (SAR) for a series of benzoxazole derivatives with many compounds demonstrating CpIMPDH IC50 values in the nanomolar range and >500-fold selectivity over human IMPDH (hIMPDH). Unlike previously reported CpIMPDH inhibitors, these compounds are competitive inhibitors versus NAD(+). The SAR study reveals that pyridine and other small heteroaromatic substituents are required at the 2-position of the benzoxazole for potent inhibitory activity. In addition, several other SAR conclusions are highlighted with regard to the benzoxazole and the amide portion of the inhibitor, including preferred stereochemistry. An X-ray crystal structure of a representative E·IMP·inhibitor complex is also presented. Overall, the secondary amine derivative 15a demonstrated excellent CpIMPDH inhibitory activity (IC50 = 0.5 ± 0.1 nM) and moderate stability (t1/2 = 44 min) in mouse liver microsomes. Compound 73, the racemic version of 15a, also displayed superb antiparasitic activity in a Toxoplasma gondii strain that relies on CpIMPDH (EC50 = 20 ± 20 nM), and selectivity versus a wild-type T. gondii strain (200-fold). No toxicity was observed (LD50 > 50 μM) against a panel of four mammalian cells lines.
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Affiliation(s)
- Suresh Kumar Gorla
- Department of Biology, Brandeis University , 415 South Street, Waltham, Massachusetts 02454, USA
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33
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Cloning, characterization and validation of inosine 5′-monophosphate dehydrogenase of Babesia gibsoni as molecular drug target. Parasitol Int 2013; 62:87-94. [DOI: 10.1016/j.parint.2012.10.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 09/28/2012] [Accepted: 10/31/2012] [Indexed: 11/18/2022]
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Characterization of the novel Trypanosoma brucei inosine 5'-monophosphate dehydrogenase. Parasitology 2013; 140:735-45. [PMID: 23369253 DOI: 10.1017/s0031182012002090] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
There is an alarming rate of human African trypanosomiasis recrudescence in many parts of sub-Saharan Africa. Yet, the disease has no successful chemotherapy. Trypanosoma lacks the enzymatic machinery for the de novo synthesis of purine nucleotides, and is critically dependent on salvage mechanisms. Inosine 5'-monophosphate dehydrogenase (IMPDH) is responsible for the rate-limiting step in guanine nucleotide metabolism. Here, we characterize recombinant Trypanosoma brucei IMPDH (TbIMPDH) to investigate the enzymatic differences between TbIMPDH and host IMPDH. Size-exclusion chromatography and analytical ultracentrifugation sedimentation velocity experiments reveal that TbIMPDH forms a heptamer, different from type 1 and 2 mammalian tetrameric IMPDHs. Kinetic analysis reveals calculated K m values of 30 and 1300 μ m for IMP and NAD, respectively. The obtained K m value of TbIMPDH for NAD is approximately 20-200-fold higher than that of mammalian enzymes and indicative of a different NAD binding mode between trypanosomal and mammalian IMPDHs. Inhibition studies show K i values of 3·2 μ m, 21 nM and 3·3 nM for ribavirin 5'-monophosphate, mycophenolic acid and mizoribine 5'-monophosphate, respectively. Our results show that TbIMPDH is different from its mammalian counterpart and thus may be a good target for further studies on anti-trypanosomal drugs.
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35
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Johnson CR, Gorla SK, Kavitha M, Zhang M, Liu X, Striepen B, Mead JR, Cuny GD, Hedstrom L. Phthalazinone inhibitors of inosine-5'-monophosphate dehydrogenase from Cryptosporidium parvum. Bioorg Med Chem Lett 2012; 23:1004-7. [PMID: 23324406 DOI: 10.1016/j.bmcl.2012.12.037] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 12/10/2012] [Accepted: 12/13/2012] [Indexed: 11/27/2022]
Abstract
Cryptosporidium parvum (Cp) is a potential biowarfare agent and major cause of diarrhea and malnutrition. This protozoan parasite relies on inosine 5'-monophosphate dehydrogenase (IMPDH) for the production of guanine nucleotides. A CpIMPDH-selective N-aryl-3,4-dihydro-3-methyl-4-oxo-1-phthalazineacetamide inhibitor was previously identified in a high throughput screening campaign. Herein we report a structure-activity relationship study for the phthalazinone-based series that resulted in the discovery of benzofuranamide analogs that exhibit low nanomolar inhibition of CpIMPDH. In addition, the antiparasitic activity of select analogs in a Toxoplasma gondii model of C. parvum infection is also presented.
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Affiliation(s)
- Corey R Johnson
- Department of Chemistry, Brandeis University, MS009, 415 South Street, Waltham, MA 02454, USA
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36
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Morrow CA, Valkov E, Stamp A, Chow EWL, Lee IR, Wronski A, Williams SJ, Hill JM, Djordjevic JT, Kappler U, Kobe B, Fraser JA. De novo GTP biosynthesis is critical for virulence of the fungal pathogen Cryptococcus neoformans. PLoS Pathog 2012; 8:e1002957. [PMID: 23071437 PMCID: PMC3469657 DOI: 10.1371/journal.ppat.1002957] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Accepted: 08/26/2012] [Indexed: 01/01/2023] Open
Abstract
We have investigated the potential of the GTP synthesis pathways as chemotherapeutic targets in the human pathogen Cryptococcus neoformans, a common cause of fatal fungal meningoencephalitis. We find that de novo GTP biosynthesis, but not the alternate salvage pathway, is critical to cryptococcal dissemination and survival in vivo. Loss of inosine monophosphate dehydrogenase (IMPDH) in the de novo pathway results in slow growth and virulence factor defects, while loss of the cognate phosphoribosyltransferase in the salvage pathway yielded no phenotypes. Further, the Cryptococcus species complex displays variable sensitivity to the IMPDH inhibitor mycophenolic acid, and we uncover a rare drug-resistant subtype of C. gattii that suggests an adaptive response to microbial IMPDH inhibitors in its environmental niche. We report the structural and functional characterization of IMPDH from Cryptococcus, revealing insights into the basis for drug resistance and suggesting strategies for the development of fungal-specific inhibitors. The crystal structure reveals the position of the IMPDH moveable flap and catalytic arginine in the open conformation for the first time, plus unique, exploitable differences in the highly conserved active site. Treatment with mycophenolic acid led to significantly increased survival times in a nematode model, validating de novo GTP biosynthesis as an antifungal target in Cryptococcus.
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Affiliation(s)
- Carl A. Morrow
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Eugene Valkov
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - Anna Stamp
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Eve W. L. Chow
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - I. Russel Lee
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Ania Wronski
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Simon J. Williams
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Justine M. Hill
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
- Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia
| | - Julianne T. Djordjevic
- Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute, University of Sydney at Westmead Hospital, Sydney, New South Wales, Australia
| | - Ulrike Kappler
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Bostjan Kobe
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - James A. Fraser
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
- * E-mail:
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Gorla SK, Kavitha M, Zhang M, Liu X, Sharling L, Gollapalli DR, Striepen B, Hedstrom L, Cuny GD. Selective and potent urea inhibitors of cryptosporidium parvum inosine 5'-monophosphate dehydrogenase. J Med Chem 2012; 55:7759-71. [PMID: 22950983 DOI: 10.1021/jm3007917] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cryptosporidium parvum and related species are zoonotic intracellular parasites of the intestine. Cryptosporidium is a leading cause of diarrhea in small children around the world. Infection can cause severe pathology in children and immunocompromised patients. This waterborne parasite is resistant to common methods of water treatment and therefore a prominent threat to drinking and recreation water even in countries with strong water safety systems. The drugs currently used to combat these organisms are ineffective. Genomic analysis revealed that the parasite relies solely on inosine-5'-monophosphate dehydrogenase (IMPDH) for the biosynthesis of guanine nucleotides. Herein, we report a selective urea-based inhibitor of C. parvum IMPDH (CpIMPDH) identified by high-throughput screening. We performed a SAR study of these inhibitors with some analogues exhibiting high potency (IC(50) < 2 nM) against CpIMPDH, excellent selectivity >1000-fold versus human IMPDH type 2 and good stability in mouse liver microsomes. A subset of inhibitors also displayed potent antiparasitic activity in a Toxoplasma gondii model.
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Affiliation(s)
- Suresh Kumar Gorla
- Department of Biology, Brandeis University , 415 South Street, Waltham, Massachusetts 02454, USA
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38
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Makowska-Grzyska M, Kim Y, Wu R, Wilton R, Gollapalli DR, Wang XK, Zhang R, Jedrzejczak R, Mack JC, Maltseva N, Mulligan R, Binkowski TA, Gornicki P, Kuhn ML, Anderson WF, Hedstrom L, Joachimiak A. Bacillus anthracis inosine 5'-monophosphate dehydrogenase in action: the first bacterial series of structures of phosphate ion-, substrate-, and product-bound complexes. Biochemistry 2012; 51:6148-63. [PMID: 22788966 DOI: 10.1021/bi300511w] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Inosine 5'-monophosphate dehydrogenase (IMPDH) catalyzes the first unique step of the GMP branch of the purine nucleotide biosynthetic pathway. This enzyme is found in organisms of all three kingdoms. IMPDH inhibitors have broad clinical applications in cancer treatment, as antiviral drugs and as immunosuppressants, and have also displayed antibiotic activity. We have determined three crystal structures of Bacillus anthracis IMPDH, in a phosphate ion-bound (termed "apo") form and in complex with its substrate, inosine 5'-monophosphate (IMP), and product, xanthosine 5'-monophosphate (XMP). This is the first example of a bacterial IMPDH in more than one state from the same organism. Furthermore, for the first time for a prokaryotic enzyme, the entire active site flap, containing the conserved Arg-Tyr dyad, is clearly visible in the structure of the apoenzyme. Kinetic parameters for the enzymatic reaction were also determined, and the inhibitory effect of XMP and mycophenolic acid (MPA) has been studied. In addition, the inhibitory potential of two known Cryptosporidium parvum IMPDH inhibitors was examined for the B. anthracis enzyme and compared with those of three bacterial IMPDHs from Campylobacter jejuni, Clostridium perfringens, and Vibrio cholerae. The structures contribute to the characterization of the active site and design of inhibitors that specifically target B. anthracis and other microbial IMPDH enzymes.
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Affiliation(s)
- Magdalena Makowska-Grzyska
- Center for Structural Genomics of Infectious Diseases, University of Chicago, 5735 South Ellis Avenue, Chicago, IL 60637, USA
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39
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Usha V, Hobrath JV, Gurcha SS, Reynolds RC, Besra GS. Identification of novel Mt-Guab2 inhibitor series active against M. tuberculosis. PLoS One 2012; 7:e33886. [PMID: 22479467 PMCID: PMC3315515 DOI: 10.1371/journal.pone.0033886] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Accepted: 02/23/2012] [Indexed: 12/17/2022] Open
Abstract
Tuberculosis (TB) remains a leading cause of mortality worldwide. With the emergence of multidrug resistant TB, extensively drug resistant TB and HIV-associated TB it is imperative that new drug targets be identified. The potential of Mycobacterium tuberculosis inosine monophosphate dehydrogenase (IMPDH) as a novel drug target was explored in the present study. IMPDH exclusively catalyzes the conversion of inosine monophosphate (IMP) to xanthosine monophosphate (XMP) in the presence of the cofactor nicotinamide adenine dinucleotide (NAD+). Although the enzyme is a dehydrogenase, the enzyme does not catalyze the reverse reaction i.e. the conversion of XMP to IMP. Unlike other bacteria, M. tuberculosis harbors three IMPDH-like genes, designated as Mt-guaB1, Mt-guaB2 and Mt-guaB3 respectively. Of the three putative IMPDH's, we previously confirmed that Mt-GuaB2 was the only functional ortholog by characterizing the enzyme kinetically. Using an in silico approach based on designed scaffolds, a series of novel classes of inhibitors was identified. The inhibitors possess good activity against M. tuberculosis with MIC values in the range of 0.4 to 11.4 µg mL−1. Among the identified ligands, two inhibitors have nanomolar Kis against the Mt-GuaB2 enzyme.
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Affiliation(s)
- Veeraraghavan Usha
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Judith V. Hobrath
- Drug Discovery Division, Southern Research Institute, Birmingham, Alabama, United States of America
| | - Sudagar S. Gurcha
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Robert C. Reynolds
- Drug Discovery Division, Southern Research Institute, Birmingham, Alabama, United States of America
| | - Gurdyal S. Besra
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- * E-mail:
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40
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Kirubakaran S, Gorla SK, Sharling L, Zhang M, Liu X, Ray SS, Macpherson IS, Striepen B, Hedstrom L, Cuny GD. Structure-activity relationship study of selective benzimidazole-based inhibitors of Cryptosporidium parvum IMPDH. Bioorg Med Chem Lett 2012; 22:1985-8. [PMID: 22310229 DOI: 10.1016/j.bmcl.2012.01.029] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 01/10/2012] [Accepted: 01/11/2012] [Indexed: 10/14/2022]
Abstract
Cryptosporidium parasites are important waterborne pathogens of both humans and animals. The Cryptosporidium parvum and Cryptosporidium hominis genomes indicate that the only route to guanine nucleotides is via inosine 5'-monophosphate dehydrogenase (IMPDH). Thus the inhibition of the parasite IMPDH presents a potential strategy for treating Cryptosporidium infections. A selective benzimidazole-based inhibitor of C. parvum IMPDH (CpIMPDH) was previously identified in a high throughput screen. Here we report a structure-activity relationship study of benzimidazole-based compounds that resulted in potent and selective inhibitors of CpIMPDH. Several compounds display potent antiparasitic activity in vitro.
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Affiliation(s)
- Sivapriya Kirubakaran
- Department of Biology, Brandeis University, MS009, 415 South Street, Waltham, MA 02454, USA
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Franco TMA, Rostirolla DC, Ducati RG, Lorenzini DM, Basso LA, Santos DS. Biochemical characterization of recombinant guaA-encoded guanosine monophosphate synthetase (EC 6.3.5.2) from Mycobacterium tuberculosis H37Rv strain. Arch Biochem Biophys 2011; 517:1-11. [PMID: 22119138 DOI: 10.1016/j.abb.2011.11.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 11/08/2011] [Accepted: 11/09/2011] [Indexed: 12/29/2022]
Abstract
Administration of the current tuberculosis (TB) vaccine to newborns is not a reliable route for preventing TB in adults. The conversion of XMP to GMP is catalyzed by guaA-encoded GMP synthetase (GMPS), and deletions in the Shiguella flexneri guaBA operon led to an attenuated auxotrophic strain. Here we present the cloning, expression, and purification of recombinant guaA-encoded GMPS from Mycobacterium tuberculosis (MtGMPS). Mass spectrometry data, oligomeric state determination, steady-state kinetics, isothermal titration calorimetry (ITC), and multiple sequence alignment are also presented. The homodimeric MtGMPS catalyzes the conversion of XMP, MgATP, and glutamine into GMP, ADP, PP(i), and glutamate. XMP, NH(4)(+), and Mg(2+) displayed positive homotropic cooperativity, whereas ATP and glutamine displayed hyperbolic saturation curves. The activity of ATP pyrophosphatase domain is independent of glutamine amidotransferase domain, whereas the latter cannot catalyze hydrolysis of glutamine to NH(3) and glutamate in the absence of substrates. ITC data suggest random order of binding of substrates, and PP(i) is the last product released. Sequence comparison analysis showed conservation of both Cys-His-Glu catalytic triad of N-terminal Class I amidotransferase and of amino acid residues of the P-loop of the N-type ATP pyrophosphatase family.
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Affiliation(s)
- Tathyana Mar A Franco
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB), Centro de Pesquisas em Biologia Molecular e Funcional (CPBMF), Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, RS, Brazil
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Breda A, Rosado LA, Lorenzini DM, Basso LA, Santos DS. Molecular, kinetic and thermodynamic characterization of Mycobacterium tuberculosis orotate phosphoribosyltransferase. MOLECULAR BIOSYSTEMS 2011; 8:572-86. [PMID: 22075667 DOI: 10.1039/c1mb05402c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Tuberculosis (TB) is a chronic infectious disease caused mainly by Mycobacterium tuberculosis. The worldwide emergence of drug-resistant strains, the increasing number of infected patients among immune compromised populations, and the large number of latent infected individuals that are reservoir to the disease have underscored the urgent need of new strategies to treat TB. The nucleotide metabolism pathways provide promising molecular targets for the development of novel drugs against active TB and may, hopefully, also be effective against latent forms of the pathogen. The orotate phosphoribosyltransferase (OPRT) enzyme of the de novo pyrimidine synthesis pathway catalyzes the reversible phosphoribosyl transfer from 5'-phospho-α-D-ribose 1'-diphosphate (PRPP) to orotic acid (OA), forming pyrophosphate and orotidine 5'-monophosphate (OMP). Here we describe cloning and characterization of pyrE-encoded protein of M. tuberculosis H37Rv strain as a homodimeric functional OPRT enzyme. The M. tuberculosis OPRT true kinetic constants for forward reaction and product inhibition results suggest a Mono-Iso Ordered Bi-Bi kinetic mechanism, which has not been previously described for this enzyme family. Absence of detection of half reaction and isothermal titration calorimetry (ITC) data support the proposed mechanism. ITC data also provided thermodynamic signatures of non-covalent interactions between substrate/product and M. tuberculosis OPRT. These data provide a solid foundation on which to base target-based rational design of anti-TB agents and should inform us how to better design inhibitors of M. tuberculosis OPRT.
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Affiliation(s)
- Ardala Breda
- Instituto Nacional de Ciência e Tecnologia em Tuberculose, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
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Riera TV, Zheng L, Josephine HR, Min D, Yang W, Hedstrom L. Allosteric activation via kinetic control: potassium accelerates a conformational change in IMP dehydrogenase. Biochemistry 2011; 50:8508-18. [PMID: 21870820 PMCID: PMC3186055 DOI: 10.1021/bi200785s] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Allosteric activators are generally believed to shift the equilibrium distribution of enzyme conformations to favor a catalytically productive structure; the kinetics of conformational exchange is seldom addressed. Several observations suggested that the usual allosteric mechanism might not apply to the activation of IMP dehydrogenase (IMPDH) by monovalent cations. Therefore, we investigated the mechanism of K(+) activation in IMPDH by delineating the kinetic mechanism in the absence of monovalent cations. Surprisingly, the K(+) dependence of k(cat) derives from the rate of flap closure, which increases by ≥65-fold in the presence of K(+). We performed both alchemical free energy simulations and potential of mean force calculations using the orthogonal space random walk strategy to computationally analyze how K(+) accelerates this conformational change. The simulations recapitulate the preference of IMPDH for K(+), validating the computational models. When K(+) is replaced with a dummy ion, the residues of the K(+) binding site relax into ordered secondary structure, creating a barrier to conformational exchange. K(+) mobilizes these residues by providing alternate interactions for the main chain carbonyls. Potential of mean force calculations indicate that K(+) changes the shape of the energy well, shrinking the reaction coordinate by shifting the closed conformation toward the open state. This work suggests that allosteric regulation can be under kinetic as well as thermodynamic control.
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Affiliation(s)
- Thomas V. Riera
- Graduate Program in Biochemistry, Brandeis University, 415 South St., MS 009, Waltham, MA 02454 USA
| | - Lianqing Zheng
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306 USA
| | - Helen R. Josephine
- Department of Biology, Brandeis University, 415 South St., MS 009, Waltham, MA 02454 USA
| | - Donghong Min
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306 USA
| | - Wei Yang
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306 USA
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306 USA
| | - Lizbeth Hedstrom
- Department of Biology, Brandeis University, 415 South St., MS 009, Waltham, MA 02454 USA
- Department of Chemistry, Brandeis University, 415 South St., MS 009, Waltham, MA 02454 USA
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Artz JD, Wernimont AK, Allali-Hassani A, Zhao Y, Amani M, Lin YH, Senisterra G, Wasney GA, Fedorov O, King O, Roos A, Lunin VV, Qiu W, Finerty P, Hutchinson A, Chau I, von Delft F, MacKenzie F, Lew J, Kozieradzki I, Vedadi M, Schapira M, Zhang C, Shokat K, Heightman T, Hui R. The Cryptosporidium parvum kinome. BMC Genomics 2011; 12:478. [PMID: 21962082 PMCID: PMC3227725 DOI: 10.1186/1471-2164-12-478] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Accepted: 09/30/2011] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Hundreds of millions of people are infected with cryptosporidiosis annually, with immunocompromised individuals suffering debilitating symptoms and children in socioeconomically challenged regions at risk of repeated infections. There is currently no effective drug available. In order to facilitate the pursuit of anti-cryptosporidiosis targets and compounds, our study spans the classification of the Cryptosporidium parvum kinome and the structural and biochemical characterization of representatives from the CDPK family and a MAP kinase. RESULTS The C. parvum kinome comprises over 70 members, some of which may be promising drug targets. These C. parvum protein kinases include members in the AGC, Atypical, CaMK, CK1, CMGC, and TKL groups; however, almost 35% could only be classified as OPK (other protein kinases). In addition, about 25% of the kinases identified did not have any known orthologues outside of Cryptosporidium spp. Comparison of specific kinases with their Plasmodium falciparum and Toxoplasma gondii orthologues revealed some distinct characteristics within the C. parvum kinome, including potential targets and opportunities for drug design. Structural and biochemical analysis of 4 representatives of the CaMK group and a MAP kinase confirms features that may be exploited in inhibitor design. Indeed, screening CpCDPK1 against a library of kinase inhibitors yielded a set of the pyrazolopyrimidine derivatives (PP1-derivatives) with IC₅₀ values of < 10 nM. The binding of a PP1-derivative is further described by an inhibitor-bound crystal structure of CpCDPK1. In addition, structural analysis of CpCDPK4 identified an unprecedented Zn-finger within the CDPK kinase domain that may have implications for its regulation. CONCLUSIONS Identification and comparison of the C. parvum protein kinases against other parasitic kinases shows how orthologue- and family-based research can be used to facilitate characterization of promising drug targets and the search for new drugs.
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Affiliation(s)
- Jennifer D Artz
- Structural Genomics Consortium, University of Toronto, MaRS South Tower, Floor 7, 101 College St, Toronto, Ontario M5G 1L7, Canada.
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Hedstrom L, Liechti G, Goldberg JB, Gollapalli DR. The antibiotic potential of prokaryotic IMP dehydrogenase inhibitors. Curr Med Chem 2011; 18:1909-18. [PMID: 21517780 DOI: 10.2174/092986711795590129] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Accepted: 04/04/2011] [Indexed: 12/30/2022]
Abstract
Inosine 5'-monophosphate dehydrogenase (IMPDH) catalyzes the first committed step of guanosine 5'-monophosphate (GMP) biosynthesis, and thus regulates the guanine nucleotide pool, which in turn governs proliferation. Human IMPDHs are validated targets for immunosuppressive, antiviral and anticancer drugs, but as yet microbial IMPDHs have not been exploited in antimicrobial chemotherapy. Selective inhibitors of IMPDH from Cryptosporidium parvum have recently been discovered that display anti-parasitic activity in cell culture models of infection. X-ray crystal structure and mutagenesis experiments identified the structural features that determine inhibitor susceptibility. These features are found in IMPDHs from a wide variety of pathogenic bacteria, including select agents and multiply drug resistant strains. A second generation inhibitor displays antibacterial activity against Helicobacter pylori, demonstrating the antibiotic potential of IMPDH inhibitors.
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Affiliation(s)
- L Hedstrom
- Brandeis University, Departments of Biology, Waltham, MA 02454-9110, USA.
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Felczak K, Chen L, Wilson D, Williams J, Vince R, Petrelli R, Jayaram HN, Kusumanchi P, Kumar M, Pankiewicz KW. Cofactor-type inhibitors of inosine monophosphate dehydrogenase via modular approach: Targeting the pyrophosphate binding sub-domain. Bioorg Med Chem 2011; 19:1594-605. [DOI: 10.1016/j.bmc.2011.01.042] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 01/14/2011] [Accepted: 01/21/2011] [Indexed: 10/18/2022]
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Gollapalli DR, Macpherson IS, Liechti G, Gorla SK, Goldberg JB, Hedstrom L. Structural determinants of inhibitor selectivity in prokaryotic IMP dehydrogenases. ACTA ACUST UNITED AC 2011; 17:1084-91. [PMID: 21035731 DOI: 10.1016/j.chembiol.2010.07.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Revised: 06/26/2010] [Accepted: 07/20/2010] [Indexed: 10/18/2022]
Abstract
The protozoan parasite Cryptosporidium parvum is a major cause of gastrointestinal disease; no effective drug therapy exists to treat this infection. Curiously, C. parvum IMPDH (CpIMPDH) is most closely related to prokaryotic IMPDHs, suggesting that the parasite obtained its IMPDH gene via horizontal transfer. We previously identified inhibitors of CpIMPDH that do not inhibit human IMPDHs. Here, we show that these compounds also inhibit IMPDHs from Helicobacter pylori, Borrelia burgdorferi, and Streptococcus pyogenes, but not from Escherichia coli. Residues Ala165 and Tyr358 comprise a structural motif that defines susceptible enzymes. Importantly, a second-generation CpIMPDH inhibitor has bacteriocidal activity on H. pylori but not E. coli. We propose that CpIMPDH-targeted inhibitors can be developed into a new class of antibiotics that will spare some commensal bacteria.
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Usha V, Gurcha SS, Lovering AL, Lloyd AJ, Papaemmanouil A, Reynolds RC, Besra GS. Identification of novel diphenyl urea inhibitors of Mt-GuaB2 active against Mycobacterium tuberculosis. MICROBIOLOGY-SGM 2010; 157:290-299. [PMID: 21081761 DOI: 10.1099/mic.0.042549-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In contrast with most bacteria, which harbour a single inosine monophosphate dehydrogenase (IMPDH) gene, the genomic sequence of Mycobacterium tuberculosis H37Rv predicts three genes encoding IMPDH: guaB1, guaB2 and guaB3. These three genes were cloned and expressed in Escherichia coli to evaluate functional IMPDH activity. Purified recombinant Mt-GuaB2, which uses inosine monophosphate as a substrate, was identified as the only active GuaB orthologue in M. tuberculosis and showed optimal activity at pH 8.5 and 37 °C. Mt-GuaB2 was inhibited significantly in vitro by a panel of diphenyl urea-based derivatives, which were also potent anti-mycobacterial agents against M. tuberculosis and Mycobacterium smegmatis, with MICs in the range of 0.2-0.5 μg ml(-1). When Mt-GuaB2 was overexpressed on a plasmid in trans in M. smegmatis, a diphenyl urea analogue showed a 16-fold increase in MIC. Interestingly, when Mt-GuaB orthologues (Mt-GuaB1 and 3) were also overexpressed on a plasmid in trans in M. smegmatis, they also conferred resistance, suggesting that although these Mt-GuaB orthologues were inactive in vitro, they presumably titrate the effect of the inhibitory properties of the active compounds in vivo.
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Affiliation(s)
- Veeraraghavan Usha
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Sudagar S Gurcha
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Andrew L Lovering
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Adrian J Lloyd
- Department of Biological Sciences, University of Warwick, Coventry, UK
| | - Athina Papaemmanouil
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Robert C Reynolds
- Drug Discovery Division, Southern Research Institute, Birmingham, AL 35255, USA
| | - Gurdyal S Besra
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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Morrow CA, Stamp A, Valkov E, Kobe B, Fraser JA. Crystallization and preliminary X-ray analysis of mycophenolic acid-resistant and mycophenolic acid-sensitive forms of IMP dehydrogenase from the human fungal pathogen Cryptococcus. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1104-7. [PMID: 20823538 PMCID: PMC2935239 DOI: 10.1107/s1744309110031659] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Accepted: 08/06/2010] [Indexed: 11/10/2022]
Abstract
Fungal human pathogens such as Cryptococcus neoformans are becoming an increasingly prevalent cause of human morbidity and mortality owing to the increasing numbers of susceptible individuals. The few antimycotics available to combat these pathogens usually target fungal-specific cell-wall or membrane-related components; however, the number of these targets is limited. In the search for new targets and lead compounds, C. neoformans has been found to be susceptible to mycophenolic acid through its target inosine monophosphate dehydrogenase (IMPDH); in contrast, a rare subtype of the related C. gattii is naturally resistant. Here, the expression, purification, crystallization and preliminary crystallographic analysis of IMPDH complexed with IMP and NAD+ is reported for both of these Cryptococcus species. The crystals of IMPDH from both sources had the symmetry of the tetragonal space group I422 and diffracted to a resolution of 2.5 A for C. neoformans and 2.6 A for C. gattii.
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Affiliation(s)
- Carl A. Morrow
- Centre for Infectious Disease Research, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Anna Stamp
- Centre for Infectious Disease Research, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Eugene Valkov
- Centre for Infectious Disease Research, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Bostjan Kobe
- Centre for Infectious Disease Research, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - James A. Fraser
- Centre for Infectious Disease Research, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
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50
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Sharling L, Liu X, Gollapalli DR, Maurya SK, Hedstrom L, Striepen B. A screening pipeline for antiparasitic agents targeting cryptosporidium inosine monophosphate dehydrogenase. PLoS Negl Trop Dis 2010; 4:e794. [PMID: 20706578 PMCID: PMC2919388 DOI: 10.1371/journal.pntd.0000794] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 07/14/2010] [Indexed: 11/30/2022] Open
Abstract
Background The protozoan parasite Cryptosporidium parvum is responsible for significant disease burden among children in developing countries. In addition Cryptosporidiosis can result in chronic and life-threatening enteritis in AIDS patients, and the currently available drugs lack efficacy in treating these severe conditions. The discovery and development of novel anti-cryptosporidial therapeutics has been hampered by the poor experimental tractability of this pathogen. While the genome sequencing effort has identified several intriguing new targets including a unique inosine monophosphate dehydrogenase (IMPDH), pursuing these targets and testing inhibitors has been frustratingly difficult. Methodology and Principal Findings Here we have developed a pipeline of tools to accelerate the in vivo screening of inhibitors of C. parvum IMPDH. We have genetically engineered the related parasite Toxoplasma gondii to serve as a model of C. parvum infection as the first screen. This assay provides crucial target validation and a large signal window that is currently not possible in assays involving C. parvum. To further develop compounds that pass this first filter, we established a fluorescence-based assay of host cell proliferation, and a C. parvum growth assay that utilizes automated high-content imaging analysis for enhanced throughput. Conclusions and Significance We have used these assays to evaluate C. parvum IMPDH inhibitors emerging from our ongoing medicinal chemistry effort and have identified a subset of 1,2,3-triazole ethers that exhibit excellent in vivo selectivity in the T. gondii model and improved anti-cryptosporidial activity. Persistent diarrhea is a leading cause of illness and death among impoverished children, and a growing share of this disease burden can be attributed to the parasite Cryptosporidium. There are no vaccines to prevent Cryptosporidium infection, and the treatment options are limited and unreliable. Critically, no effective treatment exists for children or adults suffering from AIDS. Cryptosporidium presents many technical obstacles for drug discovery; perhaps the most important roadblock is the difficulty of monitoring drug action. Here we have developed a set of methods to accelerate the drug discovery process for cryptosporidiosis. We exploit the opportunities for experimental manipulation in the related parasite Toxoplasma to genetically engineer a Cryptosporidium model. This new model parasite mirrors the metabolism of Cryptosporidium for a particularly promising drug target that supplies the building blocks for DNA and RNA. Drug effectiveness can be assayed through simple fluorescence measurements for many candidates. Using this assay as an initial filter, and adapting other assays to a high throughput format, we identify several novel chemical compounds that exhibit markedly improved anti-cryptosporidial activity and excellent selectivity.
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Affiliation(s)
- Lisa Sharling
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Xiaoping Liu
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Deviprasad R. Gollapalli
- Department of Biochemistry, Brandeis University, Waltham, Massachusetts, United States of America
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Sushil K. Maurya
- Department of Biochemistry, Brandeis University, Waltham, Massachusetts, United States of America
| | - Lizbeth Hedstrom
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
- Department of Chemistry, Brandeis University, Waltham, Massachusetts, United States of America
| | - Boris Striepen
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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