1
|
Tepper O, Appella DH, Zheng H, Dzikowski R, Yavin E. A Biotinylated cpFIT-PNA Platform for the Facile Detection of Drug Resistance to Artemisinin in Plasmodium falciparum. ACS Sens 2024; 9:1458-1464. [PMID: 38446423 PMCID: PMC10964236 DOI: 10.1021/acssensors.3c02553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 02/05/2024] [Accepted: 02/23/2024] [Indexed: 03/07/2024]
Abstract
The evolution of drug resistance to many antimalarial drugs in the lethal strain of malaria (Plasmodium falciparum) has been a great concern over the past 50 years. Among these drugs, artemisinin has become less effective for treating malaria. Indeed, several P. falciparum variants have become resistant to this drug, as elucidated by specific mutations in the pfK13 gene. This study presents the development of a diagnostic kit for the detection of a common point mutation in the pfK13 gene of P. falciparum, namely, the C580Y point mutation. FIT-PNAs (forced-intercalation peptide nucleic acid) are DNA mimics that serve as RNA sensors that fluoresce upon hybridization to their complementary RNA. Herein, FIT-PNAs were designed to sense the C580Y single nucleotide polymorphism (SNP) and were conjugated to biotin in order to bind these molecules to streptavidin-coated plates. Initial studies with synthetic RNA were conducted to optimize the sensing system. In addition, cyclopentane-modified PNA monomers (cpPNAs) were introduced to improve FIT-PNA sensing. Lastly, total RNA was isolated from red blood cells infected with P. falciparum (WT strain - NF54-WT or mutant strain - NF54-C580Y). Streptavidin plates loaded with either FIT-PNA or cpFIT-PNA were incubated with the total RNA. A significant difference in fluorescence for mutant vs WT total RNA was found only for the cpFIT-PNA probe. In summary, this study paves the way for a simple diagnostic kit for monitoring artemisinin drug resistance that may be easily adapted to malaria endemic regions.
Collapse
Affiliation(s)
- Odelia Tepper
- The
Institute for Drug Research, The School of Pharmacy, The Faculty of
Medicine, The Hebrew University of Jerusalem,
Hadassah Ein-Kerem, Jerusalem 9112102, Israel
| | - Daniel H. Appella
- Synthetic
Bioactive Molecules Section, Laboratory of Bioorganic Chemistry (LBC),
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, 8 Center Drive, Room 404, Bethesda, Maryland 20892, United States
| | - Hongchao Zheng
- Synthetic
Bioactive Molecules Section, Laboratory of Bioorganic Chemistry (LBC),
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, 8 Center Drive, Room 404, Bethesda, Maryland 20892, United States
| | - Ron Dzikowski
- Department
of Microbiology and Molecular Genetics, The institute for Medical
Research Israel - Canada, The Kuvin Center for the Study of Infectious
and Tropical Diseases, The Hebrew University-Hadassah
Medical School, Jerusalem 9112102, Israel
| | - Eylon Yavin
- The
Institute for Drug Research, The School of Pharmacy, The Faculty of
Medicine, The Hebrew University of Jerusalem,
Hadassah Ein-Kerem, Jerusalem 9112102, Israel
| |
Collapse
|
2
|
Parihar RD, Dhiman U, Bhushan A, Gupta PK, Gupta P. Heterorhabditis and Photorhabdus Symbiosis: A Natural Mine of Bioactive Compounds. Front Microbiol 2022; 13:790339. [PMID: 35422783 PMCID: PMC9002308 DOI: 10.3389/fmicb.2022.790339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 02/02/2022] [Indexed: 12/12/2022] Open
Abstract
Phylum Nematoda is of great economic importance. It has been a focused area for various research activities in distinct domains across the globe. Among nematodes, there is a group called entomopathogenic nematodes, which has two families that live in symbiotic association with bacteria of genus Xenorhabdus and Photorhabdus, respectively. With the passing years, researchers have isolated a wide array of bioactive compounds from these symbiotically associated nematodes. In this article, we are encapsulating bioactive compounds isolated from members of the family Heterorhabditidae inhabiting Photorhabdus in its gut. Isolated bioactive compounds have shown a wide range of biological activity against deadly pathogens to both plants as well as animals. Some compounds exhibit lethal effects against fungi, bacteria, protozoan, insects, cancerous cell lines, neuroinflammation, etc., with great potency. The main aim of this article is to collect and analyze the importance of nematode and its associated bacteria, isolated secondary metabolites, and their biomedical potential, which can serve as potential leads for further drug discovery.
Collapse
Affiliation(s)
| | | | - Anil Bhushan
- Natural Products and Medicinal Chemistry Division, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Integrative Medicine, Jammu, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Prashant Kumar Gupta
- Department of Horticulture, Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya, Gwalior, India
| | - Prasoon Gupta
- Natural Products and Medicinal Chemistry Division, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Integrative Medicine, Jammu, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| |
Collapse
|
3
|
Quan H, Igbasi U, Oyibo W, Omilabu S, Chen SB, Shen HM, Okolie C, Chen JH, Zhou XN. High multiple mutations of Plasmodium falciparum-resistant genotypes to sulphadoxine-pyrimethamine in Lagos, Nigeria. Infect Dis Poverty 2020; 9:91. [PMID: 32653033 PMCID: PMC7353807 DOI: 10.1186/s40249-020-00712-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 07/01/2020] [Indexed: 11/24/2022] Open
Abstract
Background Plasmodium falciparum-resistance to sulphadoxine-pyrimethamine (SP) has been largely reported among pregnant women. However, the profile of resistance markers to SP dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) in the general population are varied and not frequently monitored. Currently, SP is used as partner drug for artemisinin combination therapy (SP-artesunate) in some sub-Saharan African countries or as a prophylactic drug in intermittent preventive treatment of malaria during pregnancy and infants and in seasonal malaria chemoprevention (SMC). Profiling of P. falciparum-resistant genotypes to SP is dynamic and critical in providing data that would be useful for malaria control programmes. This study assessed the profile of dhfr and dhps genes genotypes among individuals with malaria in Lagos, Nigeria. Methods Molecular markers of SP resistance were identified by nested PCR and sequenced among malaria positive dried blood spots (DBS) that were collected from individuals attending health facilities from January 2013 to February 2014 and during community surveys from October 2010 to September 2011 across different Local Government Areas of Lagos State, Nigeria. Results A total of 242 and 167 samples were sequenced for dhfr and dhps, respectively. Sequence analysis of dhfr showed that 95.5% (231/242), 96.3% (233/242) and 96.7% (234/242) of the samples had N51I, C59R and S108N mutant alleles, respectively. The prevalence of dhps mutation at codons A437G, A613S, S436A, A581G, I431V and K540E were 95.8% (160/167), 41.9% (70/167), 41.3% (69/167), 31.1% (52/167), 25.1% (42/167), and 1.2% (2/167) respectively. The prevalence of triple mutations (CIRNI) in dhfr was 93.8% and 44.3% for the single dhps haplotype mutation (SGKAA). Partial SP-resistance due to quadruple dhfr-dhps haplotype mutations (CIRNI-SGKAA) and octuple haplotype mutations (CIRNI-VAGKGS) with rate of 42.6% and 22.0%, respectively has been reported. Conclusions There was increased prevalence in dhfr triple haplotype mutations when compared with previous reports in the same environment but aligned with high prevalence in other locations in Nigeria and other countries in Africa. Also, high prevalence of dhfr and dhps mutant alleles occurred in the study areas in Lagos, Nigeria five to eight years after the introduction of artemisinin combination therapy underscores the need for continuous monitoring.
Collapse
Affiliation(s)
- Hong Quan
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, WHO Collaborating Center for Tropical Diseases, National Centre for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, People's Republic of China.,National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention⁃Shenzhen Center for Disease Control and Prevention Joint Laboratory for Imported Tropical Disease Control, Shanghai, 200025, People's Republic of China
| | - Uche Igbasi
- Center for Infectious Diseases Research, Microbiology Department, Nigerian Institute of Medical Research, 6 Edmund Crescent, Yaba, Lagos, Nigeria
| | - Wellington Oyibo
- ANDI Center of Excellence for Malaria Diagnosis, Department of Medical Microbiology and Parasitology, College of Medicine, University of Lagos, Lagos, Nigeria
| | - Sunday Omilabu
- Department of Medical Microbiology and Parasitology, College of Medicine, University of Lagos, Lagos, Nigeria
| | - Shen-Bo Chen
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, WHO Collaborating Center for Tropical Diseases, National Centre for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, People's Republic of China.,National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention⁃Shenzhen Center for Disease Control and Prevention Joint Laboratory for Imported Tropical Disease Control, Shanghai, 200025, People's Republic of China
| | - Hai-Mo Shen
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, WHO Collaborating Center for Tropical Diseases, National Centre for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, People's Republic of China.,National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention⁃Shenzhen Center for Disease Control and Prevention Joint Laboratory for Imported Tropical Disease Control, Shanghai, 200025, People's Republic of China
| | - Chukwuma Okolie
- Department of Surveying and Geoinformatics, Faculty of Engineering, University of Lagos, Lagos, Nigeria
| | - Jun-Hu Chen
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, WHO Collaborating Center for Tropical Diseases, National Centre for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, People's Republic of China. .,National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention⁃Shenzhen Center for Disease Control and Prevention Joint Laboratory for Imported Tropical Disease Control, Shanghai, 200025, People's Republic of China.
| | - Xiao-Nong Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, WHO Collaborating Center for Tropical Diseases, National Centre for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, People's Republic of China.,National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention⁃Shenzhen Center for Disease Control and Prevention Joint Laboratory for Imported Tropical Disease Control, Shanghai, 200025, People's Republic of China
| |
Collapse
|
4
|
Mahmud AW, Shallangwa GA, Uzairu A. In silico modeling of tetraoxane-8-aminoquinoline hybrids active against Plasmodium falciparum. BENI-SUEF UNIVERSITY JOURNAL OF BASIC AND APPLIED SCIENCES 2020. [DOI: 10.1186/s43088-020-00044-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Abstract
Background
Quantitative structure-activity relationships (QSAR) is a technique that is used to produce a model that connects biological activities of compounds to their chemical structures, and molecular docking is a technique that reveals the binding mode and interactions between a drug and its target enzyme. These techniques have been successfully applied in the design and development of many drug candidates and herein were employed to build a model that could help in the development of more potent antimalaria drugs.
Results
Descriptors of the compounds were calculated using the PaDEL-Descriptor software, and Genetic Function Algorithm (GFA) was used to select descriptors and build the model. A robust and reliable model was generated and validated to have internal and external squared correlation coefficient (R2) of 0.9622 and 0.8191, respectively, adjusted squared correlation coefficient (Radj) of 0.9471, and leave-one-out (LOO) cross-validation coefficient (Q2cv) of 0.9223. The model revealed that the antiplasmodial activities of 1,2,4,5-tetraoxane-8-aminoquinoline hybrids depend on MATS3m, GATS8p, GATS8i, and RDF50s descriptors. MATS3m, GATS8i, and RDF50s influenced the antiplasmodial activities of the compounds positively while GATS8p negatively with the greatest influence. The docking result shows strong interactions between 1,2,4,5-tetraoxane-8-aminoquinoline hybrids and Plasmodium falciparum lactate dehydrogenase (pfLDH) with binding affinities ranging from − 6.3 to − 10.9 kcal/mol which were better than that of chloroquine (− 6.1 kcal/mol), suggesting that these compounds could be better inhibitors of pfLDH than chloroquine.
Conclusion
The results of this study could serve as a model for designing new potent 1,2,4,5-tetraoxane-8-aminoquinolines with better antiplasmodial activities for the development of highly active antimalaria drugs.
Collapse
|
5
|
Zhao L, Vo TD, Kaiser M, Bode HB. Phototemtide A, a Cyclic Lipopeptide Heterologously Expressed from Photorhabdus temperata Meg1, Shows Selective Antiprotozoal Activity. Chembiochem 2020; 21:1288-1292. [PMID: 31814269 PMCID: PMC7317862 DOI: 10.1002/cbic.201900665] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Indexed: 12/20/2022]
Abstract
A new cyclic lipopeptide, phototemtide A (1), was isolated from Escherichia coli expressing the biosynthetic gene cluster pttABC from Photorhabdus temperata Meg1. The structure of 1 was elucidated by HR-ESI-MS and NMR experiments. The absolute configurations of amino acids and 3-hydroxyoctanoic acid in 1 were determined by using the advanced Marfey's method and comparison after total synthesis of 1, respectively. Additionally, three new minor derivatives, phototemtides B-D (2-4), were identified by detailed HPLC-MS analysis. Phototemtide A (1) showed weak antiprotozoal activity against Plasmodium falciparum, with an IC50 value of 9.8 μm. The biosynthesis of phototemtides A-D (1-4) was also proposed.
Collapse
Affiliation(s)
- Lei Zhao
- Molecular Biotechnology, Department of Biosciences, Goethe University Frankfurt, Max-von-Laue-Strasse 9, 60438, Frankfurt am Main, Germany.,Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, QianHuHouCun 1, 210014, Nanjing, China
| | - Tien Duy Vo
- Molecular Biotechnology, Department of Biosciences, Goethe University Frankfurt, Max-von-Laue-Strasse 9, 60438, Frankfurt am Main, Germany
| | - Marcel Kaiser
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland
| | - Helge B Bode
- Molecular Biotechnology, Department of Biosciences, Goethe University Frankfurt, Max-von-Laue-Strasse 9, 60438, Frankfurt am Main, Germany.,Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt, Max-von-Laue-Strasse 15, 60438, Frankfurt am Main, Germany
| |
Collapse
|
6
|
Abstract
A marked decrease in malaria-related deaths worldwide has been attributed to the administration of effective antimalarials against Plasmodium falciparum, in particular, artemisinin-based combination therapies (ACTs). Increasingly, ACTs are also used to treat Plasmodium vivax, the second major human malaria parasite. However, resistance to frontline artemisinins and partner drugs is now causing the failure of P. falciparum ACTs in southeast Asia. In this Review, we discuss our current knowledge of markers and mechanisms of resistance to artemisinins and ACTs. In particular, we describe the identification of mutations in the propeller domains of Kelch 13 as the primary marker for artemisinin resistance in P. falciparum and explore two major mechanisms of resistance that have been independently proposed: the activation of the unfolded protein response and proteostatic dysregulation of parasite phosphatidylinositol 3- kinase. We emphasize the continuing challenges and the imminent need to understand mechanisms of resistance to improve parasite detection strategies, develop new combinations to eliminate resistant parasites and prevent their global spread.
Collapse
|
7
|
Nguetse CN, Adegnika AA, Agbenyega T, Ogutu BR, Krishna S, Kremsner PG, Velavan TP. Molecular markers of anti-malarial drug resistance in Central, West and East African children with severe malaria. Malar J 2017; 16:217. [PMID: 28535801 PMCID: PMC5442681 DOI: 10.1186/s12936-017-1868-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/17/2017] [Indexed: 11/10/2022] Open
Abstract
Background The Plasmodium falciparum multidrug resistance 1 (PfMDR1), P. falciparum Ca2+-ATPase (PfATP6) and Kelch-13 propeller domain (PfK13) loci are molecular markers of parasite susceptibility to anti-malarial drugs. Their frequency distributions were determined in the isolates collected from children with severe malaria originating from three African countries. Methods Samples from 287 children with severe malaria [(Gabon: n = 114); (Ghana: n = 89); (Kenya: n = 84)] were genotyped for pfmdr1, pfatp6 and pfk13 loci by DNA sequencing and assessing pfmdr1 copy number variation (CNV) by real-time PCR. Results Pfmdr1-N86Y mutation was detected in 48, 10 and 10% in Lambaréné, Kumasi and Kisumu, respectively. At codon 184, the prevalence of the mutation was 73% in Lambaréné, 63% in Kumasi and 49% Kisumu. The S1034C and N1042D variants were absent at all three sites, while the frequency of the D1246Y mutation was 1, 3 and 13% in Lambaréné, Kumasi and Kisumu, respectively. Isolates with two pfmdr1 gene copy number predominantly harboured the N86Y wild-type allele and were mostly found in Kumasi (10%) (P < 0.0001). Among the main pfmdr1 haplotypes (NFD, NYD and YFD), NYD was associated with highest parasitaemia (P = 0.04). At the pfatp6 locus, H243Y and A623E mutations were observed at very low frequency at all three sites. The prevalence of the pfatp6 E431K variant was 6, 18 and 17% in Lambaréné, Kumasi and Kisumu, respectively. The L263E and S769N mutations were absent in all isolates. The pfk13 variants associated with artemisinin resistance in Southeast Asia were not observed. Eleven novel substitutions in the pfk13 locus occurring at low frequency were observed. Conclusions Artemisinins are still highly efficacious in large malaria-endemic regions though declining efficacy has occurred in Southeast Asia. The return of chloroquine-sensitive strains following the removal of drug pressure is observed. However, selection of wild-type alleles in the multidrug-resistance gene and the increased gene copy number is associated with reduced lumefantrine sensitivity. This study indicates a need to constantly monitor drug resistance to artemisinin in field isolates from malaria-endemic countries.
Collapse
Affiliation(s)
- Christian N Nguetse
- Institute of Tropical Medicine, University Tübingen, Wilhelmstrasse 27, 72074, Tübingen, Germany
| | - Ayola Akim Adegnika
- Institute of Tropical Medicine, University Tübingen, Wilhelmstrasse 27, 72074, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Tsiri Agbenyega
- Department of Physiology, University of Science and Technology, School of Medical Sciences, Kumasi, Ghana.,Departments of Child Health and Medicine, Komfo Anokye Teaching Hospital, Kumasi, Ghana
| | - Bernhards R Ogutu
- Centre for Clinical Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Sanjeev Krishna
- Institute of Tropical Medicine, University Tübingen, Wilhelmstrasse 27, 72074, Tübingen, Germany.,Institute for Infection and Immunity, St George's University of London, London, UK
| | - Peter G Kremsner
- Institute of Tropical Medicine, University Tübingen, Wilhelmstrasse 27, 72074, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Thirumalaisamy P Velavan
- Institute of Tropical Medicine, University Tübingen, Wilhelmstrasse 27, 72074, Tübingen, Germany. .,Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo. .,Vietnamese-German Center for Medical Research, Hanoi, Vietnam. .,Faculty of Medicine, Duy Tan University, Da Nang, Vietnam.
| |
Collapse
|
8
|
Yang S, Qiang L, Sample A, Shah P, He YY. NF-κB Signaling Activation Induced by Chloroquine Requires Autophagosome, p62 Protein, and c-Jun N-terminal Kinase (JNK) Signaling and Promotes Tumor Cell Resistance. J Biol Chem 2017; 292:3379-3388. [PMID: 28082672 DOI: 10.1074/jbc.m116.756536] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 01/10/2017] [Indexed: 12/30/2022] Open
Abstract
Macroautophagy (hereafter autophagy) is a catabolic cellular self-eating process by which unwanted organelles or proteins are delivered to lysosomes for degradation through autophagosomes. Although the role of autophagy in cancer has been shown to be context-dependent, the role of autophagy in tumor cell survival has attracted great interest in targeting autophagy for cancer therapy. One family of potential autophagy blockers is the quinoline-derived antimalarial family, including chloroquine (CQ). However, the molecular basis for tumor cell response to CQ remains poorly understood. We show here that in both squamous cell carcinoma cells and melanoma tumor cells, CQ induced NF-κB activation and the expression of its target genes HIF-1α, IL-8, BCL-2, and BCL-XL through the accumulation of autophagosomes, p62, and JNK signaling. The activation of NF-κB further increased p62 gene expression. Either genetic knockdown of p62 or inhibition of NF-κB sensitized tumor cells to CQ, resulting in increased apoptotic cell death following treatment. Our findings provide new molecular insights into the CQ response in tumor cells and CQ resistance in cancer therapy. These findings may facilitate development of improved therapeutic strategies by targeting the p62/NF-κB pathway.
Collapse
Affiliation(s)
| | - Lei Qiang
- Department of Medicine, Section of Dermatology
| | - Ashley Sample
- Department of Medicine, Section of Dermatology; Committee on Cancer Biology, University of Chicago, Chicago, Illinois 60637
| | - Palak Shah
- Department of Medicine, Section of Dermatology
| | - Yu-Ying He
- Department of Medicine, Section of Dermatology; Committee on Cancer Biology, University of Chicago, Chicago, Illinois 60637.
| |
Collapse
|
9
|
Cloete TT, de Kock C, Smith PJ, N'Da DD. Synthesis, in vitro antiplasmodial activity and cytotoxicity of a series of artemisinin–triazine hybrids and hybrid-dimers. Eur J Med Chem 2014; 76:470-81. [DOI: 10.1016/j.ejmech.2014.01.040] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 01/15/2014] [Accepted: 01/18/2014] [Indexed: 12/11/2022]
|
10
|
Molette J, Routier J, Abla N, Besson D, Bombrun A, Brun R, Burt H, Georgi K, Kaiser M, Nwaka S, Muzerelle M, Scheer A. Identification and optimization of an aminoalcohol-carbazole series with antimalarial properties. ACS Med Chem Lett 2013; 4:1037-41. [PMID: 24900603 DOI: 10.1021/ml400015f] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Accepted: 09/22/2013] [Indexed: 12/13/2022] Open
Abstract
Recent observations on the emergence of artemisinin resistant parasites have highlighted the need for new antimalarial treatments. An HTS campaign led to the identification of the 1-(1-aminopropan-2-ol)carbazole analogues as potent hits against Plasmodium falciparum K1 strain. The SAR study and optimization of early ADME and physicochemical properties direct us to the selection of a late lead compound that shows good efficacy when orally administrated in the in vivo P. berghei mouse model.
Collapse
Affiliation(s)
- Jérôme Molette
- Merck Serono, 9 chemin des mines, 1202 Geneva, Switzerland
| | - Julie Routier
- Merck Serono, 9 chemin des mines, 1202 Geneva, Switzerland
| | - Nada Abla
- Merck Serono, 9 chemin des mines, 1202 Geneva, Switzerland
| | - Dominique Besson
- Special Program for Research & Training in Tropical Diseases (TDR), World Health Organization, Avenue Appia 20, 1211 Geneva 27, Switzerland
| | - Agnes Bombrun
- Merck Serono, 9 chemin des mines, 1202 Geneva, Switzerland
| | - Reto Brun
- Swiss Tropical and Public Health Institute, Socinstrasse. 57, 4051 Basel, Switzerland, and University of Basel, Petersplatz 1, 4003 Basel, Switzerland
| | - Howard Burt
- Merck Serono, 9 chemin des mines, 1202 Geneva, Switzerland
| | - Katrin Georgi
- Merck Serono, 9 chemin des mines, 1202 Geneva, Switzerland
| | - Marcel Kaiser
- Swiss Tropical and Public Health Institute, Socinstrasse. 57, 4051 Basel, Switzerland, and University of Basel, Petersplatz 1, 4003 Basel, Switzerland
| | - Solomon Nwaka
- Special Program for Research & Training in Tropical Diseases (TDR), World Health Organization, Avenue Appia 20, 1211 Geneva 27, Switzerland
| | | | | |
Collapse
|
11
|
Duah NO, Matrevi SA, de Souza DK, Binnah DD, Tamakloe MM, Opoku VS, Onwona CO, Narh CA, Quashie NB, Abuaku B, Duplessis C, Kronmann KC, Koram KA. Increased pfmdr1 gene copy number and the decline in pfcrt and pfmdr1 resistance alleles in Ghanaian Plasmodium falciparum isolates after the change of anti-malarial drug treatment policy. Malar J 2013; 12:377. [PMID: 24172030 PMCID: PMC3819684 DOI: 10.1186/1475-2875-12-377] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 10/28/2013] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND With the introduction of artemisinin-based combination therapy (ACT) in 2005, monitoring of anti-malarial drug efficacy, which includes the use of molecular tools to detect known genetic markers of parasite resistance, is important for first-hand information on the changes in parasite susceptibility to drugs in Ghana. This study investigated the Plasmodium falciparum multidrug resistance gene (pfmdr1) copy number, mutations and the chloroquine resistance transporter gene (pfcrt) mutations in Ghanaian isolates collected in seven years to detect the trends in prevalence of mutations. METHODS Archived filter paper blood blots collected from children aged below five years with uncomplicated malaria in 2003-2010 at sentinel sites were used. Using quantitative real-time polymerase chain reaction (qRT-PCR), 756 samples were assessed for pfmdr1 gene copy number. PCR and restriction fragment length polymorphism (RFLP) were used to detect alleles of pfmdr1 86 in 1,102 samples, pfmdr1 184, 1034, 1042 and 1246 in 832 samples and pfcrt 76 in 1,063 samples. Merozoite surface protein 2 (msp2) genotyping was done to select monoclonal infections for copy number analysis. RESULTS The percentage of isolates with increased pfmdr1 copy number were 4, 27, 9, and 18% for 2003-04, 2005-06, 2007-08 and 2010, respectively. Significant increasing trends for prevalence of pfmdr1 N86 (×(2) = 96.31, p <0.001) and pfcrt K76 (×(2) = 64.50, p <0.001) and decreasing trends in pfmdr1 Y86 (x(2) = 38.52, p <0.001) and pfcrt T76 (x(2) = 43.49, p <0.001) were observed from 2003-2010. The pfmdr1 F184 and Y184 prevalence showed an increasing and decreasing trends respectively but were not significant (×(2) = 7.39,p=0.060; ×(2) = 7.49, p = 0.057 respectively). The pfmdr1 N86-F184-D1246 haplotype, which is alleged to be selected by artemether-lumefantrine showed a significant increasing trend (×(2) = 20.75, p < 0.001). CONCLUSION Increased pfmdr1 gene copy number was observed in the isolates analysed and this finding has implications for the use of ACT in the country although no resistance has been reported. The decreasing trend in the prevalence of chloroquine resistance markers after change of treatment policy presents the possibility for future introduction of chloroquine as prophylaxis for malaria risk groups such as children and pregnant women in Ghana.
Collapse
Affiliation(s)
- Nancy O Duah
- Epidemiology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, PO Box LG581, Legon, Ghana.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Trafficked Proteins-Druggable in Plasmodium falciparum? Int J Cell Biol 2013; 2013:435981. [PMID: 23710183 PMCID: PMC3655585 DOI: 10.1155/2013/435981] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Accepted: 03/12/2013] [Indexed: 01/09/2023] Open
Abstract
Malaria is an infectious disease that results in serious health problems in the countries in which it is endemic. Annually this parasitic disease leads to more than half a million deaths; most of these are children in Africa. An effective vaccine is not available, and the treatment of the disease is solely dependent on chemotherapy. However, drug resistance is spreading, and the identification of new drug targets as well as the development of new antimalarials is urgently required. Attention has been drawn to a variety of essential plasmodial proteins, which are targeted to intra- or extracellular destinations, such as the digestive vacuole, the apicoplast, or into the host cell. Interfering with the action or the transport of these proteins will impede proliferation of the parasite. In this mini review, we will shed light on the present discovery of chemotherapeutics and potential drug targets involved in protein trafficking processes in the malaria parasite.
Collapse
|
13
|
Shahinas D, Folefoc A, Pillai DR. Targeting Plasmodium falciparum Hsp90: Towards Reversing Antimalarial Resistance. Pathogens 2013; 2:33-54. [PMID: 25436880 PMCID: PMC4235713 DOI: 10.3390/pathogens2010033] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 01/18/2013] [Accepted: 01/23/2013] [Indexed: 12/29/2022] Open
Abstract
Malaria continues to exact a great human toll in tropical settings. Antimalarial resistance is rife and the parasite inexorably develops mechanisms to outwit our best drugs, including the now first-line choice, artesunate. Novel strategies to circumvent resistance are needed. Here we detail drug development focusing on heat shock protein 90 and its central role as a chaperone. A growing body of evidence supports the role for Hsp90 inhibitors as adjunctive drugs able to restore susceptibility to traditionally efficacious compounds like chloroquine.
Collapse
Affiliation(s)
- Dea Shahinas
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Canada.
| | - Asongna Folefoc
- Department of Pathology & Laboratory Medicine, The University of Calgary, Calgary, AB, Canada.
| | - Dylan R Pillai
- Department of Pathology & Laboratory Medicine, The University of Calgary, Calgary, AB, Canada.
| |
Collapse
|
14
|
Brown T, Smith LS, Oo EKS, Shawng K, Lee TJ, Sullivan D, Beyrer C, Richards AK. Molecular surveillance for drug-resistant Plasmodium falciparum in clinical and subclinical populations from three border regions of Burma/Myanmar: cross-sectional data and a systematic review of resistance studies. Malar J 2012; 11:333. [PMID: 22992214 PMCID: PMC3518194 DOI: 10.1186/1475-2875-11-333] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 08/15/2012] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Confirmation of artemisinin-delayed parasite clearance in Plasmodium falciparum along the Thai-Myanmar border has inspired a global response to contain and monitor drug resistance to avert the disastrous consequences of a potential spread to Africa. However, resistance data from Myanmar are sparse, particularly from high-risk areas where limited health services and decades of displacement create conditions for resistance to spread. Subclinical infections may represent an important reservoir for resistance genes that confer a fitness disadvantage relative to wild-type alleles. This study estimates the prevalence of resistance genotypes in three previously unstudied remote populations in Myanmar and tests the a priori hypothesis that resistance gene prevalence would be higher among isolates collected from subclinical infections than isolates collected from febrile clinical patients. A systematic review of resistance studies is provided for context. METHODS Community health workers in Karen and Kachin States and an area spanning the Indo-Myanmar border collected dried blood spots from 988 febrile clinical patients and 4,591 villagers with subclinical infection participating in routine prevalence surveys. Samples positive for P. falciparum 18 s ribosomal RNA by real-time PCR were genotyped for P. falciparum multidrug resistance protein (pfmdr1) copy number and the pfcrt K76T polymorphism using multiplex real-time PCR. RESULTS Pfmdr1 copy number increase and the pfcrt K76 polymorphism were determined for 173 and 269 isolates, respectively. Mean pfmdr1 copy number was 1.2 (range: 0.7 to 3.7). Pfmdr1 copy number increase was present in 17.5%, 9.6% and 11.1% of isolates from Karen and Kachin States and the Indo-Myanmar border, respectively. Pfmdr1 amplification was more prevalent in subclinical isolates (20.3%) than clinical isolates (6.4%, odds ratio 3.7, 95% confidence interval 1.1 - 12.5). Pfcrt K76T prevalence ranged from 90-100%. CONCLUSIONS Community health workers can contribute to molecular surveillance of drug resistance in remote areas of Myanmar. Marginal and displaced populations under-represented among previous resistance investigations can and should be included in resistance surveillance efforts, particularly once genetic markers of artemisinin-delayed parasite clearance are identified. Subclinical infections may contribute to the epidemiology of drug resistance, but determination of gene amplification from desiccated filter samples requires further validation when DNA concentration is low.
Collapse
Affiliation(s)
- Tyler Brown
- Johns Hopkins University School of Medicine, Broadway Research Building, 733 N. Broadway, Suite 147, Baltimore, MD, 21205, USA
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
| | - Linda S Smith
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
| | - Eh Kalu Shwe Oo
- Karen Department of Health and Welfare, PO Box 189, Mae Sot, Tak, 63110, Thailand
| | - Kum Shawng
- Office of the Director of the Health Department, Kachin Baptist Convention 135/Shan Su (South), Myitkyina, Kachin State, Myanmar
| | - Thomas J Lee
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
- School of Medicine, University of California at Los Angeles, 924 Westwood Blvd, Suite 300, Los Angeles, CA, 90024, USA
| | - David Sullivan
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health 615 North Wolfe St, Room E5628, Baltimore, MD, 21205, USA
| | - Chris Beyrer
- Department of Epidemiology Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St., Suite E7152, Baltimore, MD, 21205, USA
| | - Adam K Richards
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
- Department of General Internal Medicine and Health Services Research, University of California at Los Angeles, 911 Broxton Ave, Los Angeles, CA, 90025, USA
| |
Collapse
|
15
|
The aminopeptidase inhibitor CHR-2863 is an orally bioavailable inhibitor of murine malaria. Antimicrob Agents Chemother 2012; 56:3244-9. [PMID: 22450967 DOI: 10.1128/aac.06245-11] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Malaria remains a significant risk in many areas of the world, with resistance to the current antimalarial pharmacopeia an ever-increasing problem. The M1 alanine aminopeptidase (PfM1AAP) and M17 leucine aminopeptidase (PfM17LAP) are believed to play a role in the terminal stages of digestion of host hemoglobin and thereby generate a pool of free amino acids that are essential for parasite growth and development. Here, we show that an orally bioavailable aminopeptidase inhibitor, CHR-2863, is efficacious against murine malaria.
Collapse
|
16
|
Akala HM, Eyase FL, Cheruiyot AC, Omondi AA, Ogutu BR, Waters NC, Johnson JD, Polhemus ME, Schnabel DC, Walsh DS. Antimalarial drug sensitivity profile of western Kenya Plasmodium falciparum field isolates determined by a SYBR Green I in vitro assay and molecular analysis. Am J Trop Med Hyg 2011; 85:34-41. [PMID: 21734121 DOI: 10.4269/ajtmh.2011.10-0674] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In vitro drug sensitivity and molecular analyses of Plasmodium falciparum track drug resistance. DNA-binding fluorescent dyes like SYBR Green I may allow field laboratories, proximal to P. falciparum collection sites, to conduct drug assays. In 2007-2008, we assayed 121 P. falciparum field isolates from western Kenya for 50% inhibitory concentrations (IC(50)) against 6 antimalarial drugs using a SYBR Green I in vitro assay: 91 immediate ex vivo (IEV) and 30 culture-adapted, along with P. falciparum reference clones D6 (chloroquine [CQ] sensitive) and W2 (CQ resistant). We also assessed P. falciparum mdr1 (Pfmdr1) copy number and single nucleotide polymorphisms (SNPs) at four codons. The IC(50)s for IEV and culture-adapted P. falciparum isolates were similar, and approximated historical IC(50)s. For Pfmdr1, mean copy number was 1, with SNPs common at codons 86 and 184. The SYBR Green I assay adapted well to our field-based laboratory, for both IEV and culture-adapted P. falciparum, warranting continued use.
Collapse
Affiliation(s)
- Hoseah M Akala
- Global Emerging Infections Surveillance (GEIS) Program, United States Army Medical Research Unit-Kenya (USAMRU-K), Kenya Medical Research Institute (KEMRI)-Walter Reed Project, Kisumu and Nairobi, Kenya.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
In vitro sensitivity of Plasmodium falciparum clinical isolates from the China-Myanmar border area to quinine and association with polymorphism in the Na+/H+ exchanger. Antimicrob Agents Chemother 2010; 54:4306-13. [PMID: 20643902 DOI: 10.1128/aac.00321-10] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Quinine resistance (QNR) in Plasmodium falciparum has been detected in many regions of the world where malaria is endemic. Genetic polymorphisms in at least four genes are implicated in QN susceptibility, and their significance often depends on the genetic background of the parasites. In this study, we have culture-adapted 60 P. falciparum clinical isolates from the China-Myanmar border and assessed their in vitro responses to QN. Our results showed that >50% of the parasite isolates displayed reduced sensitivity to QN, with a half-maximal inhibitory concentration (IC(50)) above 500 nM. Genotyping of pfcrt found that an overwhelming proportion of the parasite population had the chloroquine-resistant genotype, whereas pfmdr1 mutation genotypes and gene amplification were rare. Genotyping of the P. falciparum Na(+)/H(+) exchanger gene (pfnhe1) at the minisatellite ms4760 locus identified 10 haplotypes. Haplotype 7, which harbors three copies of the DNNND repeat, was the most predominant, accounting for nearly half of the parasite isolates. Correlation studies did not reveal significant associations of the polymorphisms in pfcrt and pfmdr1 genes with QN response. However, the ms4760 haplotypes were highly associated with in vitro QN responses. In particular, parasite isolates with an increased DNNND copy number tended to have significantly reduced QN susceptibility, whereas parasite isolates with a higher NHNDNHNNDDD copy number had increased QN susceptibility. This study provided further support for the importance of pfnhe1 polymorphisms in influencing QNR in P. falciparum.
Collapse
|
18
|
Das MK, Lumb V, Mittra P, Singh SS, Dash AP, Sharma YD. High chloroquine treatment failure rates and predominance of mutant genotypes associated with chloroquine and antifolate resistance among falciparum malaria patients from the island of Car Nicobar, India. J Antimicrob Chemother 2010; 65:1258-61. [DOI: 10.1093/jac/dkq090] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
19
|
Ma X, Yan L, He L, He D, Lu H. Ocular fundus manifestation of two patients following long-term chloroquine therapy: a case report. Diagn Pathol 2010; 5:20. [PMID: 20346186 PMCID: PMC2859853 DOI: 10.1186/1746-1596-5-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2010] [Accepted: 03/29/2010] [Indexed: 11/10/2022] Open
Abstract
This report describes the typical manifestations of chloroquine retinopathy with some advanced new technology. A series of examinations were performed on the patients, including the fundus fluorescein angiography, optical coherence tomography, GDxVCC Nerve Fiber Analyzer, full-field electroretinography, multifocal electroretinography and visual field examinations, to provide a better understanding of chloroquine retinopathy.
Collapse
Affiliation(s)
- Xiaoyun Ma
- Department of Ophthalmology, Guanghua Rheumatoid Arthritis Specialized Hospital, Shanghai, China.
| | | | | | | | | |
Collapse
|
20
|
Skinner-Adams TS, Stack CM, Trenholme KR, Brown CL, Grembecka J, Lowther J, Mucha A, Drag M, Kafarski P, McGowan S, Whisstock JC, Gardiner DL, Dalton JP. Plasmodium falciparum neutral aminopeptidases: new targets for anti-malarials. Trends Biochem Sci 2009; 35:53-61. [PMID: 19796954 DOI: 10.1016/j.tibs.2009.08.004] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 08/05/2009] [Accepted: 08/05/2009] [Indexed: 11/19/2022]
Abstract
The neutral aminopeptidases M1 alanyl aminopeptidase (PfM1AAP) and M17 leucine aminopeptidase (PfM17LAP) of the human malaria parasite Plasmodium falciparum are targets for the development of novel anti-malarial drugs. Although the functions of these enzymes remain unknown, they are believed to act in the terminal stages of haemoglobin degradation, generating amino acids essential for parasite growth and development. Inhibitors of both enzymes are lethal to P. falciparum in culture and kill the murine malaria P. chabaudi in vivo. Recent biochemical, structural and functional studies provide the substrate specificity and mechanistic binding data needed to guide the development of more potent anti-malarial drugs. Together with biological studies, these data form the rationale for choosing PfM1AAP and PfM17LAP as targets for anti-malarial development.
Collapse
Affiliation(s)
- Tina S Skinner-Adams
- Malaria Biology Laboratory, Queensland Institute of Medical Research, Herston, QLD 4006, Australia.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Faik I, de Carvalho EG, Kun JF. Parasite-host interaction in malaria: genetic clues and copy number variation. Genome Med 2009; 1:82. [PMID: 19725943 PMCID: PMC2768989 DOI: 10.1186/gm82] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In humans, infections contribute highly to mortality and morbidity rates worldwide. Malaria tropica is one of the major infectious diseases globally and is caused by the protozoan parasite Plasmodium falciparum. Plasmodia have accompanied human beings since the emergence of humankind. Due to its pathogenicity, malaria is a powerful selective force on the human genome. Genetic epidemiology approaches such as family and twin studies, candidate gene studies, and disease-association studies have identified a number of genes that mediate relative protection against the severest forms of the disease. New molecular approaches, including genome-wide association studies, have recently been performed to expand our knowledge on the functional effect of human variation in malaria. For the future, a systematic determination of gene-dosage effects and expression profiles of protective genes might unveil the functional impact of structural alterations in these genes on either side of the host-parasite interaction.
Collapse
Affiliation(s)
- Imad Faik
- Institute for Tropical Medicine, University Tübingen, Wilhelmstr, 27, 72074 Tübingen, Germany
| | | | | |
Collapse
|
22
|
Nkrumah LJ, Riegelhaupt PM, Moura P, Johnson DJ, Patel J, Hayton K, Ferdig MT, Wellems TE, Akabas MH, Fidock DA. Probing the multifactorial basis of Plasmodium falciparum quinine resistance: evidence for a strain-specific contribution of the sodium-proton exchanger PfNHE. Mol Biochem Parasitol 2009; 165:122-31. [PMID: 19428659 DOI: 10.1016/j.molbiopara.2009.01.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Revised: 01/15/2009] [Accepted: 01/20/2009] [Indexed: 01/10/2023]
Abstract
Quinine (QN) continues to be an important treatment option for severe malaria, however resistance to this drug has emerged in field isolates of the etiologic agent Plasmodium falciparum. Quantitative trait loci investigations of QN resistance have mapped three loci of this complex trait. Two coincide with pfcrt and pfmdr1, involved in resistance to chloroquine (CQ) and other quinoline-based antimalarials. A third locus on chromosome 13 contains the sodium-proton exchanger (pfnhe) gene. Previous studies have associated pfnhe polymorphisms with reduced QN sensitivity in culture-adapted field isolates. Here, we provide direct evidence supporting the hypothesis that pfnhe contributes to QN resistance. Using allelic exchange, we reduced pfnhe expression by introducing a truncated 3' untranslated region (UTR) from pfcrt into the endogenous pfnhe 3'UTR. Transfections were performed with 1BB5 and 3BA6 (both CQ- and QN-resistant) as well as GC03 (CQ- and QN-sensitive), all progenies of the HB3xDd2 genetic cross. RNA and protein analyses of the ensuing recombinant clones demonstrated a approximately 50% decrease in pfnhe expression levels. A statistically significant 30% decrease in QN IC(50) values was associated with these decreased expression levels in 1BB5 and 3BA6 but not in GC03. CQ, mefloquine and lumefantrine IC(50) values were unaltered. Cytosolic pH values were similar in all parental lines and recombinant clones. Our observations support a role for pfnhe in QN resistance in a strain-dependent manner, which might be contingent on pre-existing resistance to CQ and/or QN. These data bolster observations that QN resistance is a complex trait requiring the contribution of multiple transporter proteins.
Collapse
Affiliation(s)
- Louis J Nkrumah
- Department of Microbiology and Immunology, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Ferguson HM, Ng'habi KR, Walder T, Kadungula D, Moore SJ, Lyimo I, Russell TL, Urassa H, Mshinda H, Killeen GF, Knols BG. Establishment of a large semi-field system for experimental study of African malaria vector ecology and control in Tanzania. Malar J 2008; 7:158. [PMID: 18715508 PMCID: PMC2543042 DOI: 10.1186/1475-2875-7-158] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Accepted: 08/20/2008] [Indexed: 01/08/2023] Open
Abstract
Background Medical entomologists increasingly recognize that the ability to make inferences between laboratory experiments of vector biology and epidemiological trends observed in the field is hindered by a conceptual and methodological gap occurring between these approaches which prevents hypothesis-driven empirical research from being conducted on relatively large and environmentally realistic scales. The development of Semi-Field Systems (SFS) has been proposed as the best mechanism for bridging this gap. Semi-field systems are defined as enclosed environments, ideally situated within the natural ecosystem of a target disease vector and exposed to ambient environmental conditions, in which all features necessary for its life cycle completion are present. Although the value of SFS as a research tool for malaria vector biology is gaining recognition, only a few such facilities exist worldwide and are relatively small in size (< 100 m2). Methods The establishment of a 625 m2 state-of-the-art SFS for large-scale experimentation on anopheline mosquito ecology and control within a rural area of southern Tanzania, where malaria transmission intensities are amongst the highest ever recorded, is described. Results A greenhouse frame with walls of mosquito netting and a polyethylene roof was mounted on a raised concrete platform at the Ifakara Health Institute. The interior of the SFS was divided into four separate work areas that have been set up for a variety of research activities including mass-rearing for African malaria vectors under natural conditions, high throughput evaluation of novel mosquito control and trapping techniques, short-term assays of host-seeking behaviour and olfaction, and longer-term experimental investigation of anopheline population dynamics and gene flow within a contained environment that simulates a local village domestic setting. Conclusion The SFS at Ifakara was completed and ready for use in under two years. Preliminary observations indicate that realistic and repeatable observations of anopheline behaviour are obtainable within the SFS, and that habitat and climatic features representative of field conditions can be simulated within it. As work begins in the SFS in Ifakara and others around the world, the major opportunities and challenges to the successful application of this tool for malaria vector research and control are discussed.
Collapse
Affiliation(s)
- Heather M Ferguson
- Division of Infection and Immunity, University of Glasgow, G128TA Glasgow, UK.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Sidhu ABS, Uhlemann AC, Valderramos SG, Valderramos JC, Krishna S, Fidock DA. Decreasing pfmdr1 copy number in plasmodium falciparum malaria heightens susceptibility to mefloquine, lumefantrine, halofantrine, quinine, and artemisinin. J Infect Dis 2006; 194:528-35. [PMID: 16845638 PMCID: PMC2978021 DOI: 10.1086/507115] [Citation(s) in RCA: 285] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Accepted: 06/16/2006] [Indexed: 11/04/2022] Open
Abstract
The global dissemination of drug-resistant Plasmodium falciparum is spurring intense efforts to implement artemisinin (ART)-based combination therapies for malaria, including mefloquine (MFQ)-artesunate and lumefantrine (LUM)-artemether. Clinical studies have identified an association between an increased risk of MFQ, MFQ-artesunate, and LUM-artemether treatment failures and pfmdr1 gene amplification. To directly address the contribution that pfmdr1 copy number makes to drug resistance, we genetically disrupted 1 of the 2 pfmdr1 copies in the drug-resistant FCB line, which resulted in reduced pfmdr1 mRNA and protein expression. These knockdown clones manifested a 3-fold decrease in MFQ IC(50) values, compared with that for the FCB line, verifying the role played by pfmdr1 expression levels in mediating resistance to MFQ. These clones also showed increased susceptibility to LUM, halofantrine, quinine, and ART. No change was observed for chloroquine. These results highlight the importance of pfmdr1 copy number in determining P. falciparum susceptibility to multiple agents currently being used to combat malaria caused by multidrug-resistant parasites.
Collapse
Affiliation(s)
- Amar Bir Singh Sidhu
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, Bronx, NY 10461, USA
| | | | | | | | | | | |
Collapse
|
25
|
Krishna S, Woodrow CJ, Staines HM, Haynes RK, Mercereau-Puijalon O. Re-evaluation of how artemisinins work in light of emerging evidence of in vitro resistance. Trends Mol Med 2006; 12:200-5. [PMID: 16616639 PMCID: PMC2682190 DOI: 10.1016/j.molmed.2006.03.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Revised: 03/02/2006] [Accepted: 03/27/2006] [Indexed: 11/18/2022]
Abstract
There are more than half a billion cases of malaria every year. Combinations of an artemisinin with other antimalarial drugs are now recommended treatments for Plasmodium falciparum malaria in most endemic areas. These treatment regimens act rapidly to relieve symptoms and effect cure. There is considerable controversy on how artemisinins work and over emerging indications of resistance to this class of antimalarial drugs. Several individual molecules have been proposed as targets for artemisinins, in addition to the idea that artemisinins might have many targets at the same time. Our suggestion that artemisinins inhibit the parasite-encoded sarco–endoplasmic reticulum Ca2+-ATPase (SERCA) PfATP6 has gained support from recent observations that a polymorphism in the gene encoding PfATP6 is associated with in vitro resistance to artemether in field isolates of P. falciparum.
Collapse
Affiliation(s)
- Sanjeev Krishna
- Centre for Infection, Division of Cellular and Molecular Medicine, St. George's, University of London SW17 0RE, UK.
| | | | | | | | | |
Collapse
|