1
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Kane J, Li X, Kumar S, Button-Simons KA, Brenneman KMV, Dahlhoff H, Sievert MA, Checkley LA, Shoue DA, Singh PP, Abatiyow BA, Haile MT, Nair S, Reyes A, Tripura R, Peto T, Lek D, Kappe SH, Dhorda M, Nkhoma SC, Cheeseman IH, Vaughan AM, Anderson TJC, Ferdig MT. A Plasmodium falciparum genetic cross reveals the contributions of pfcrt and plasmepsin II/III to piperaquine drug resistance. bioRxiv 2023:2023.06.06.543862. [PMID: 37745488 PMCID: PMC10515748 DOI: 10.1101/2023.06.06.543862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Piperaquine (PPQ) is widely used in combination with dihydroartemisinin (DHA) as a first-line treatment against malaria parasites. Multiple genetic drivers of PPQ resistance have been reported, including mutations in the Plasmodium falciparum chloroquine resistance transporter (pfcrt) and increased copies of plasmepsin II/III (pm2/3). We generated a cross between a Cambodia-derived multi-drug resistant KEL1/PLA1 lineage isolate (KH004) and a drug susceptible parasite isolated in Malawi (Mal31). Mal31 harbors a wild-type (3D7-like) pfcrt allele and a single copy of pm2/3, while KH004 has a chloroquine-resistant (Dd2-like) pfcrt allele with an additional G367C substitution and four copies of pm2/3. We recovered 104 unique recombinant progeny and examined a targeted set of progeny representing all possible combinations of variants at pfcrt and pm2/3 for detailed analysis of competitive fitness and a range of PPQ susceptibility phenotypes, including PPQ survival assay (PSA), area under the dose-response curve (AUC), and a limited point IC50 (LP-IC50). We find that inheritance of the KH004 pfcrt allele is required for PPQ resistance, whereas copy number variation in pm2/3 further enhances resistance but does not confer resistance in the absence of PPQ-R-associated mutations in pfcrt. Deeper investigation of genotype-phenotype relationships demonstrates that progeny clones from experimental crosses can be used to understand the relative contributions of pfcrt, pm2/3, and parasite genetic background, to a range of PPQ-related traits and confirm the critical role of the PfCRT G367C substitution in PPQ resistance.
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Affiliation(s)
- John Kane
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Xue Li
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Sudhir Kumar
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Katrina A. Button-Simons
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | | | - Haley Dahlhoff
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Mackenzie A.C. Sievert
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Lisa A. Checkley
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Douglas A. Shoue
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Puspendra P. Singh
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Biley A. Abatiyow
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Meseret T. Haile
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Shalini Nair
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Ann Reyes
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Rupam Tripura
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
| | - Tom Peto
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
| | - Dysoley Lek
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
- School of Public Health, National Institute of Public Health, Phnom Penh, Cambodia
| | - Stefan H.I. Kappe
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - Mehul Dhorda
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
| | - Standwell C Nkhoma
- BEI Resources, American Type Culture Collection (ATCC), Manassas, VA, USA
| | - Ian H. Cheeseman
- Host Pathogen Interactions Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Ashley M. Vaughan
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - Timothy J. C. Anderson
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Michael T. Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
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2
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Amambua-Ngwa A, Button-Simons KA, Li X, Kumar S, Brenneman KV, Ferrari M, Checkley LA, Haile MT, Shoue DA, McDew-White M, Tindall SM, Reyes A, Delgado E, Dalhoff H, Larbalestier JK, Amato R, Pearson RD, Taylor AB, Nosten FH, D'Alessandro U, Kwiatkowski D, Cheeseman IH, Kappe SHI, Avery SV, Conway DJ, Vaughan AM, Ferdig MT, Anderson TJC. Chloroquine resistance evolution in Plasmodium falciparum is mediated by the putative amino acid transporter AAT1. Nat Microbiol 2023; 8:1213-1226. [PMID: 37169919 PMCID: PMC10322710 DOI: 10.1038/s41564-023-01377-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 03/29/2023] [Indexed: 05/13/2023]
Abstract
Malaria parasites break down host haemoglobin into peptides and amino acids in the digestive vacuole for export to the parasite cytoplasm for growth: interrupting this process is central to the mode of action of several antimalarial drugs. Mutations in the chloroquine (CQ) resistance transporter, pfcrt, located in the digestive vacuole membrane, confer CQ resistance in Plasmodium falciparum, and typically also affect parasite fitness. However, the role of other parasite loci in the evolution of CQ resistance is unclear. Here we use a combination of population genomics, genetic crosses and gene editing to demonstrate that a second vacuolar transporter plays a key role in both resistance and compensatory evolution. Longitudinal genomic analyses of the Gambian parasites revealed temporal signatures of selection on a putative amino acid transporter (pfaat1) variant S258L, which increased from 0% to 97% in frequency between 1984 and 2014 in parallel with the pfcrt1 K76T variant. Parasite genetic crosses then identified a chromosome 6 quantitative trait locus containing pfaat1 that is selected by CQ treatment. Gene editing demonstrated that pfaat1 S258L potentiates CQ resistance but at a cost of reduced fitness, while pfaat1 F313S, a common southeast Asian polymorphism, reduces CQ resistance while restoring fitness. Our analyses reveal hidden complexity in CQ resistance evolution, suggesting that pfaat1 may underlie regional differences in the dynamics of resistance evolution, and modulate parasite resistance or fitness by manipulating the balance between both amino acid and drug transport.
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Affiliation(s)
- Alfred Amambua-Ngwa
- MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Katrina A Button-Simons
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Xue Li
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Sudhir Kumar
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Katelyn Vendrely Brenneman
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Marco Ferrari
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Lisa A Checkley
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Meseret T Haile
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Douglas A Shoue
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Marina McDew-White
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Sarah M Tindall
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Ann Reyes
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Elizabeth Delgado
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Haley Dalhoff
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - James K Larbalestier
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | | | | | - Alexander B Taylor
- Department of Biochemistry & Structural Biology, University of Texas Health Science Center at San Antonio, Antonio, TX, USA
| | - François H Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Umberto D'Alessandro
- MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | | | - Ian H Cheeseman
- Host Pathogen Interactions Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Stefan H I Kappe
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
- Department of Pediatrics, University of Washington, Seattle, WA, USA
- Department of Global Health, University of Washington, Seattle, WA, USA
| | - Simon V Avery
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - David J Conway
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Ashley M Vaughan
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA.
- Department of Pediatrics, University of Washington, Seattle, WA, USA.
| | - Michael T Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA.
| | - Timothy J C Anderson
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA.
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3
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Pires CV, Oberstaller J, Wang C, Casandra D, Zhang M, Chawla J, Adapa SR, Otto TD, Ferdig MT, Rayner JC, Jiang RHY, Adams JH. Chemogenomic Profiling of a Plasmodium falciparum Transposon Mutant Library Reveals Shared Effects of Dihydroartemisinin and Bortezomib on Lipid Metabolism and Exported Proteins. Microbiol Spectr 2023; 11:e0501422. [PMID: 37067430 PMCID: PMC10269874 DOI: 10.1128/spectrum.05014-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 03/21/2023] [Indexed: 04/18/2023] Open
Abstract
The antimalarial activity of the frontline drug artemisinin involves generation of reactive oxygen species (ROS) leading to oxidative damage of parasite proteins. To achieve homeostasis and maintain protein quality control in the overwhelmed parasite, the ubiquitin-proteasome system kicks in. Even though molecular markers for artemisinin resistance like pfkelch13 have been identified, the intricate network of mechanisms driving resistance remains to be elucidated. Here, we report a forward genetic screening strategy that enables a broader identification of genetic factors responsible for altering sensitivity to dihydroartemisinin (DHA) and a proteasome inhibitor, bortezomib (BTZ). Using a library of isogenic piggyBac mutants in P. falciparum, we defined phenotype-genotype associations influencing drug responses and highlighted shared mechanisms between the two processes, which mainly included proteasome-mediated degradation and the lipid metabolism genes. Additional transcriptomic analysis of a DHA/BTZ-sensitive piggyBac mutant showed it is possible to find differences between the two response mechanisms on the specific components for regulation of the exportome. Our results provide further insight into the molecular mechanisms of antimalarial drug resistance. IMPORTANCE Malaria control is seriously threatened by the emergence and spread of Plasmodium falciparum resistance to the leading antimalarial, artemisinin. The potent killing activity of artemisinin results from oxidative damage unleashed by free heme activation released by hemoglobin digestion. Although the ubiquitin-proteasome system is considered critical for parasite survival of this toxicity, the diverse genetic changes linked to artemisinin resistance are complex and, so far, have not included the ubiquitin-proteasome system. In this study, we use a systematic forward genetic approach by screening a library of P. falciparum random piggyBac mutants to decipher the genetic factors driving malaria parasite responses to the oxidative stress caused by antimalarial drugs. This study compares phenotype-genotype associations influencing dihydroartemisinin responses with the proteasome inhibitor bortezomib to delineate the role of ubiquitin-proteasome system. Our study highlights shared and unique pathways from the complex array of molecular processes critical for P. falciparum survival resulting from the oxidative damage of artemisinin.
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Affiliation(s)
- Camilla Valente Pires
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Jenna Oberstaller
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Chengqi Wang
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Debora Casandra
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Min Zhang
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Jyotsna Chawla
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
| | - Swamy Rakesh Adapa
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Thomas D. Otto
- Institute of Infection, Immunity and Inflammation, MVLS, University of Glasgow, Glasgow, United Kingdom
| | - Michael T. Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Julian C. Rayner
- Cambridge Institute for Medical Research, Cambridge Biomedical Campus, University of Cambridge, Cambridge, United Kingdom
| | - Rays H. Y. Jiang
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - John H. Adams
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- USF Genomics Program, College of Public Health, University of South Florida, Tampa, Florida, USA
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4
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Tiwari R, Checkley L, Ferdig MT, Vennerstrom JL, Miller MJ. Synthesis and antimalarial activity of amide and ester conjugates of siderophores and ozonides. Biometals 2023; 36:315-320. [PMID: 35229216 PMCID: PMC9433463 DOI: 10.1007/s10534-022-00375-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 02/14/2022] [Indexed: 11/25/2022]
Abstract
Despite advances in chemotherapeutic interventions for the treatment of malaria, there is a continuing need for the development of new antimalarial agents. Previous studies indicated that co-administration of chloroquine with antioxidants such as the iron chelator deferoxamine (DFO) prevented the development of persistent cognitive damage in surrogate models of cerebral malaria. The work described herein reports the syntheses and antimalarial activities of covalent conjugates of both natural (siderophores) and artificial iron chelators, namely DFO, ferricrocin and ICL-670, with antimalarial 1,2,4-trioxolanes (ozonides). All of the synthesized conjugates had potent antimalarial activities against the in vitro cultures of drug resistant and drug sensitive strains of Plasmodium falciparum. The work described herein provides the basis for future development of covalent combination of iron chelators and antimalarial chemotherapeutic agents for the treatment of cerebral malaria.
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Affiliation(s)
- Rohit Tiwari
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Lisa Checkley
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Michael T Ferdig
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Jonathan L Vennerstrom
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Marvin J Miller
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA.
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5
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Kumar S, Li X, McDew-White M, Reyes A, Delgado E, Sayeed A, Haile MT, Abatiyow BA, Kennedy SY, Camargo N, Checkley LA, Brenneman KV, Button-Simons KA, Duraisingh MT, Cheeseman IH, Kappe SHI, Nosten F, Ferdig MT, Vaughan AM, Anderson TJC. A Malaria Parasite Cross Reveals Genetic Determinants of Plasmodium falciparum Growth in Different Culture Media. Front Cell Infect Microbiol 2022; 12:878496. [PMID: 35711667 PMCID: PMC9197316 DOI: 10.3389/fcimb.2022.878496] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/28/2022] [Indexed: 12/21/2022] Open
Abstract
What genes determine in vitro growth and nutrient utilization in asexual blood-stage malaria parasites? Competition experiments between NF54, clone 3D7, a lab-adapted African parasite, and a recently isolated Asian parasite (NHP4026) reveal contrasting outcomes in different media: 3D7 outcompetes NHP4026 in media containing human serum, while NHP4026 outcompetes 3D7 in media containing AlbuMAX, a commercial lipid-rich bovine serum formulation. To determine the basis for this polymorphism, we conducted parasite genetic crosses using humanized mice and compared genome-wide allele frequency changes in three independent progeny populations cultured in media containing human serum or AlbuMAX. This bulk segregant analysis detected three quantitative trait loci (QTL) regions [on chromosome (chr) 2 containing aspartate transaminase AST; chr 13 containing EBA-140; and chr 14 containing cysteine protease ATG4] linked with differential growth in serum or AlbuMAX in each of the three independent progeny pools. Selection driving differential growth was strong (s = 0.10 – 0.23 per 48-hour lifecycle). We conducted validation experiments for the strongest QTL on chr 13: competition experiments between ΔEBA-140 and 3D7 wildtype parasites showed fitness reversals in the two medium types as seen in the parental parasites, validating this locus as the causative gene. These results (i) demonstrate the effectiveness of bulk segregant analysis for dissecting fitness traits in P. falciparum genetic crosses, and (ii) reveal intimate links between red blood cell invasion and nutrient composition of growth media. Use of parasite crosses combined with bulk segregant analysis will allow systematic dissection of key nutrient acquisition/metabolism and red blood cell invasion pathways in P. falciparum.
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Affiliation(s)
- Sudhir Kumar
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Xue Li
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Marina McDew-White
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Ann Reyes
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Elizabeth Delgado
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Abeer Sayeed
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Meseret T. Haile
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Biley A. Abatiyow
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Spencer Y. Kennedy
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Nelly Camargo
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Lisa A. Checkley
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States
| | - Katelyn V. Brenneman
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States
| | - Katrina A. Button-Simons
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States
| | - Manoj T. Duraisingh
- Immunology and Infectious Diseases Department, Harvard T.H. Chan School of Public Health, Boston, MA, United States
| | - Ian H. Cheeseman
- Program in Host Pathogen Interactions, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Stefan H. I. Kappe
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
- Department of Pediatrics, University of Washington, Seattle, WA, United States
| | - François Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research building, University of Oxford, Oxford, United Kingdom
| | - Michael T. Ferdig
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States
| | - Ashley M. Vaughan
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
- Department of Pediatrics, University of Washington, Seattle, WA, United States
- *Correspondence: Ashley M. Vaughan, ; Tim J. C. Anderson,
| | - Tim J. C. Anderson
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, United States
- *Correspondence: Ashley M. Vaughan, ; Tim J. C. Anderson,
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Brenneman KV, Li X, Kumar S, Delgado E, Checkley LA, Shoue DA, Reyes A, Abatiyow BA, Haile MT, Tripura R, Peto T, Lek D, Button-Simons KA, Kappe SH, Dhorda M, Nosten F, Nkhoma SC, Cheeseman IH, Vaughan AM, Ferdig MT, Anderson TJ. Optimizing bulk segregant analysis of drug resistance using Plasmodium falciparum genetic crosses conducted in humanized mice. iScience 2022; 25:104095. [PMID: 35372813 PMCID: PMC8971943 DOI: 10.1016/j.isci.2022.104095] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/24/2022] [Accepted: 03/11/2022] [Indexed: 01/15/2023] Open
Abstract
Classical malaria parasite genetic crosses involve isolation, genotyping, and phenotyping of progeny parasites, which is time consuming and laborious. We tested a rapid alternative approach-bulk segregant analysis (BSA)-that utilizes sequencing of bulk progeny populations with and without drug selection for rapid identification of drug resistance loci. We used dihydroartemisinin (DHA) selection in two genetic crosses and investigated how synchronization, cryopreservation, and the drug selection regimen impacted BSA success. We detected a robust quantitative trait locus (QTL) at kelch13 in both crosses but did not detect QTLs at four other candidate loci. QTLs were detected using synchronized, but not unsynchronized progeny pools, consistent with the stage-specific action of DHA. We also successfully applied BSA to cryopreserved progeny pools, expanding the utility of this approach. We conclude that BSA provides a powerful approach for investigating the genetic architecture of drug resistance in Plasmodium falciparum.
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Affiliation(s)
- Katelyn Vendrely Brenneman
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Xue Li
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Sudhir Kumar
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Elizabeth Delgado
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Lisa A. Checkley
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Douglas A. Shoue
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Ann Reyes
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Biley A. Abatiyow
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Meseret T. Haile
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Rupam Tripura
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
| | - Tom Peto
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
| | - Dysoley Lek
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
- School of Public Health, National Institute of Public Health, Phnom Penh, Cambodia
| | - Katrina A. Button-Simons
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Stefan H.I. Kappe
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - Mehul Dhorda
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
| | - François Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | | | - Ian H. Cheeseman
- Program in Host Pathogen Interactions, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Ashley M. Vaughan
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Pediatrics, University of Washington, Seattle, WA, USA
- Corresponding author
| | - Michael T. Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
- Corresponding author
| | - Tim J.C. Anderson
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, USA
- Corresponding author
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7
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Turnbull LB, Button-Simons KA, Agbayani N, Ferdig MT. Sources of transcription variation in Plasmodium falciparum. J Genet Genomics 2022; 49:965-974. [PMID: 35395422 DOI: 10.1016/j.jgg.2022.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 12/20/2022]
Abstract
Variation in transcript abundance can contribute to both short-term environmental response and long-term evolutionary adaptation. Most studies are designed to assess differences in mean transcription levels and do not consider other potentially important and confounding sources of transcriptional variation. Detailed quantification of variation sources will improve our ability to detect and identify the mechanisms that contribute to genome-wide transcription changes that underpin adaptive responses. To quantify innate levels of expression variation, we measured mRNA levels for more than 5000 genes in the malaria parasite, Plasmodium falciparum, among clones derived from two parasite strains across biologically and experimentally replicated batches. Using a mixed effects model, we partitioned the total variation among four sources - between strain, within strain, environmental batch effects, and stochastic noise. We found 646 genes with significant variation attributable to at least one of these sources. These genes were categorized by their predominant variation source and further examined using gene ontology enrichment analysis to associate function with each source of variation. Genes with environmental batch effect and within strain transcript variation may contribute to phenotypic plasticity, while genes with between strain variation may contribute to adaptive responses and processes that lead to parasite strain-specific survival under varied conditions.
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Affiliation(s)
- Lindsey B Turnbull
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Katrina A Button-Simons
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Nestor Agbayani
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA; Rush School of Medicine, Chicago, IL, 60612, USA
| | - Michael T Ferdig
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA.
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8
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Foster GJ, Sievert MAC, Button-Simons K, Vendrely KM, Romero-Severson J, Ferdig MT. Cyclical regression covariates remove the major confounding effect of cyclical developmental gene expression with strain-specific drug response in the malaria parasite Plasmodium falciparum. BMC Genomics 2022; 23:180. [PMID: 35247977 PMCID: PMC8897900 DOI: 10.1186/s12864-021-08281-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 12/24/2021] [Indexed: 12/21/2022] Open
Abstract
Background The cyclical nature of gene expression in the intraerythrocytic development cycle (IDC) of the malaria parasite, Plasmodium falciparum, confounds the accurate detection of specific transcriptional differences, e.g. as provoked by the development of drug resistance. In lab-based studies, P. falciparum cultures are synchronized to remove this confounding factor, but the rapid detection of emerging resistance to artemisinin therapies requires rapid analysis of transcriptomes extracted directly from clinical samples. Here we propose the use of cyclical regression covariates (CRC) to eliminate the major confounding effect of developmentally driven transcriptional changes in clinical samples. We show that elimination of this confounding factor reduces both Type I and Type II errors and demonstrate the effectiveness of this approach using a published dataset of 1043 transcriptomes extracted directly from patient blood samples with different patient clearance times after treatment with artemisinin. Results We apply this method to two publicly available datasets and demonstrate its ability to reduce the confounding of differences in transcript levels due to misaligned intraerythrocytic development time. Adjusting the clinical 1043 transcriptomes dataset with CRC results in detection of fewer functional categories than previously reported from the same data set adjusted using other methods. We also detect mostly the same functional categories, but observe fewer genes within these categories. Finally, the CRC method identifies genes in a functional category that was absent from the results when the dataset was adjusted using other methods. Analysis of differential gene expression in the clinical data samples that vary broadly for developmental stage resulted in the detection of far fewer transcripts in fewer functional categories while, at the same time, identifying genes in two functional categories not present in the unadjusted data analysis. These differences are consistent with the expectation that CRC reduces both false positives and false negatives with the largest effect on datasets from samples with greater variance in developmental stage. Conclusions Cyclical regression covariates have immediate application to parasite transcriptome sequencing directly from clinical blood samples and to cost-constrained in vitro experiments. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-08281-y.
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9
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Button-Simons KA, Kumar S, Carmago N, Haile MT, Jett C, Checkley LA, Kennedy SY, Pinapati RS, Shoue DA, McDew-White M, Li X, Nosten FH, Kappe SH, Anderson TJC, Romero-Severson J, Ferdig MT, Emrich SJ, Vaughan AM, Cheeseman IH. The power and promise of genetic mapping from Plasmodium falciparum crosses utilizing human liver-chimeric mice. Commun Biol 2021; 4:734. [PMID: 34127785 PMCID: PMC8203791 DOI: 10.1038/s42003-021-02210-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 04/30/2021] [Indexed: 12/30/2022] Open
Abstract
Genetic crosses are most powerful for linkage analysis when progeny numbers are high, parental alleles segregate evenly and numbers of inbred progeny are minimized. We previously developed a novel genetic crossing platform for the human malaria parasite Plasmodium falciparum, an obligately sexual, hermaphroditic protozoan, using mice carrying human hepatocytes (the human liver-chimeric FRG NOD huHep mouse) as the vertebrate host. We report on two genetic crosses-(1) an allopatric cross between a laboratory-adapted parasite (NF54) of African origin and a recently patient-derived Asian parasite, and (2) a sympatric cross between two recently patient-derived Asian parasites. We generated 144 unique recombinant clones from the two crosses, doubling the number of unique recombinant progeny generated in the previous 30 years. The allopatric African/Asian cross has minimal levels of inbreeding and extreme segregation distortion, while in the sympatric Asian cross, inbred progeny predominate and parental alleles segregate evenly. Using simulations, we demonstrate that these progeny provide the power to map small-effect mutations and epistatic interactions. The segregation distortion in the allopatric cross slightly erodes power to detect linkage in several genome regions. We greatly increase the power and the precision to map biomedically important traits with these new large progeny panels.
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Affiliation(s)
- Katrina A Button-Simons
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA.
| | - Sudhir Kumar
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Nelly Carmago
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Meseret T Haile
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Catherine Jett
- Host Pathogen Interactions Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Lisa A Checkley
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Spencer Y Kennedy
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | | | - Douglas A Shoue
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Marina McDew-White
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Xue Li
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - François H Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
| | - Stefan H Kappe
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Timothy J C Anderson
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | | | - Michael T Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | | | - Ashley M Vaughan
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Ian H Cheeseman
- Host Pathogen Interactions Program, Texas Biomedical Research Institute, San Antonio, TX, USA.
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10
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Davis SZ, Singh PP, Vendrely KM, Shoue DA, Checkley LA, McDew-White M, Button-Simons KA, Cassady Z, Sievert MAC, Foster GJ, Nosten FH, Anderson TJC, Ferdig MT. The extended recovery ring-stage survival assay provides a superior association with patient clearance half-life and increases throughput. Malar J 2020; 19:54. [PMID: 32005233 PMCID: PMC6995136 DOI: 10.1186/s12936-020-3139-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 01/24/2020] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Tracking and understanding artemisinin resistance is key for preventing global setbacks in malaria eradication efforts. The ring-stage survival assay (RSA) is the current gold standard for in vitro artemisinin resistance phenotyping. However, the RSA has several drawbacks: it is relatively low throughput, has high variance due to microscopy readout, and correlates poorly with the current benchmark for in vivo resistance, patient clearance half-life post-artemisinin treatment. Here a modified RSA is presented, the extended Recovery Ring-stage Survival Assay (eRRSA), using 15 cloned patient isolates from Southeast Asia with a range of patient clearance half-lives, including parasite isolates with and without kelch13 mutations. METHODS Plasmodium falciparum cultures were synchronized with single layer Percoll during the schizont stage of the intraerythrocytic development cycle. Cultures were left to reinvade to early ring-stage and parasitaemia was quantified using flow cytometry. Cultures were diluted to 2% haematocrit and 0.5% parasitaemia in a 96-well plate to start the assay, allowing for increased throughput and decreased variability between biological replicates. Parasites were treated with 700 nM of dihydroartemisinin or 0.02% dimethyl sulfoxide (DMSO) for 6 h, washed three times in drug-free media, and incubated for 66 or 114 h, when samples were collected and frozen for PCR amplification. A SYBR Green-based quantitative PCR method was used to quantify the fold-change between treated and untreated samples. RESULTS 15 cloned patient isolates from Southeast Asia with a range of patient clearance half-lives were assayed using the eRRSA. Due to the large number of pyknotic and dying parasites at 66 h post-exposure (72 h sample), parasites were grown for an additional cell cycle (114 h post-exposure, 120 h sample), which drastically improved correlation with patient clearance half-life compared to the 66 h post-exposure sample. A Spearman correlation of - 0.8393 between fold change and patient clearance half-life was identified in these 15 isolates from Southeast Asia, which is the strongest correlation reported to date. CONCLUSIONS eRRSA drastically increases the efficiency and accuracy of in vitro artemisinin resistance phenotyping compared to the traditional RSA, which paves the way for extensive in vitro phenotyping of hundreds of artemisinin resistant parasites.
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Affiliation(s)
- Sage Z Davis
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA.,Molecular, Cell, and Systems Biology Department, University of California Riverside, Riverside, CA, USA
| | - Puspendra P Singh
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Katelyn M Vendrely
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Douglas A Shoue
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Lisa A Checkley
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | | | - Katrina A Button-Simons
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Zione Cassady
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Mackenzie A C Sievert
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Gabriel J Foster
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - François H Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
| | | | - Michael T Ferdig
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA.
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11
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Li X, Kumar S, McDew-White M, Haile M, Cheeseman IH, Emrich S, Button-Simons K, Nosten F, Kappe SHI, Ferdig MT, Anderson TJC, Vaughan AM. Genetic mapping of fitness determinants across the malaria parasite Plasmodium falciparum life cycle. PLoS Genet 2019; 15:e1008453. [PMID: 31609965 PMCID: PMC6821138 DOI: 10.1371/journal.pgen.1008453] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 10/30/2019] [Accepted: 10/01/2019] [Indexed: 12/14/2022] Open
Abstract
Determining the genetic basis of fitness is central to understanding evolution and transmission of microbial pathogens. In human malaria parasites (Plasmodium falciparum), most experimental work on fitness has focused on asexual blood stage parasites, because this stage can be easily cultured, although the transmission of malaria requires both female Anopheles mosquitoes and vertebrate hosts. We explore a powerful approach to identify the genetic determinants of parasite fitness across both invertebrate and vertebrate life-cycle stages of P. falciparum. This combines experimental genetic crosses using humanized mice, with selective whole genome amplification and pooled sequencing to determine genome-wide allele frequencies and identify genomic regions under selection across multiple lifecycle stages. We applied this approach to genetic crosses between artemisinin resistant (ART-R, kelch13-C580Y) and ART-sensitive (ART-S, kelch13-WT) parasites, recently isolated from Southeast Asian patients. Two striking results emerge: we observed (i) a strong genome-wide skew (>80%) towards alleles from the ART-R parent in the mosquito stage, that dropped to ~50% in the blood stage as selfed ART-R parasites were selected against; and (ii) repeatable allele specific skews in blood stage parasites with particularly strong selection (selection coefficient (s) ≤ 0.18/asexual cycle) against alleles from the ART-R parent at loci on chromosome 12 containing MRP2 and chromosome 14 containing ARPS10. This approach robustly identifies selected loci and has strong potential for identifying parasite genes that interact with the mosquito vector or compensatory loci involved in drug resistance.
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Affiliation(s)
- Xue Li
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Sudhir Kumar
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - Marina McDew-White
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Meseret Haile
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - Ian H. Cheeseman
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Scott Emrich
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
- Electrical Engineering and Computer Science, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Katie Button-Simons
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - François Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Stefan H. I. Kappe
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Michael T. Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Tim J. C. Anderson
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
- * E-mail: (TJCA); (AMV)
| | - Ashley M. Vaughan
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, United States of America
- * E-mail: (TJCA); (AMV)
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12
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Tirrell AR, Vendrely KM, Checkley LA, Davis SZ, McDew-White M, Cheeseman IH, Vaughan AM, Nosten FH, Anderson TJC, Ferdig MT. Pairwise growth competitions identify relative fitness relationships among artemisinin resistant Plasmodium falciparum field isolates. Malar J 2019; 18:295. [PMID: 31462253 PMCID: PMC6714446 DOI: 10.1186/s12936-019-2934-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 08/23/2019] [Indexed: 02/08/2023] Open
Abstract
Background Competitive outcomes between co-infecting malaria parasite lines can reveal fitness disparities in blood stage growth. Blood stage fitness costs often accompany the evolution of drug resistance, with the expectation that relatively fitter parasites will be more likely to spread in populations. With the recent emergence of artemisinin resistance, it is important to understand the relative competitive fitness of the metabolically active asexual blood stage parasites. Genetically distinct drug resistant parasite clones with independently evolved sets of mutations are likely to vary in asexual proliferation rate, contributing to their chance of transmission to the mosquito vector. Methods An optimized in vitro 96-well plate-based protocol was used to quantitatively measure-head-to-head competitive fitness during blood stage development between seven genetically distinct field isolates from a hotspot of emerging artemisinin resistance and the laboratory strain, NF54. These field isolates were isolated from patients in Southeast Asia carrying different alleles of kelch13 and included both artemisinin-sensitive and artemisinin-resistant isolates. Fluorescent labeled microsatellite markers were used to track the relative densities of each parasite throughout the co-growth period of 14–60 days. All-on-all competitions were conducted for the panel of eight parasite lines (28 pairwise competitions) to determine their quantitative competitive fitness relationships. Results Twenty-eight pairwise competitive growth outcomes allowed for an unambiguous ranking among a set of seven genetically distinct parasite lines isolated from patients in Southeast Asia displaying a range of both kelch13 alleles and clinical clearance times and a laboratory strain, NF54. This comprehensive series of assays established the growth relationships among the eight parasite lines. Interestingly, a clinically artemisinin resistant parasite line that carries the wild-type form of kelch13 outcompeted all other parasites in this study. Furthermore, a kelch13 mutant line (E252Q) was competitively more fit without drug than lines with other resistance-associated kelch13 alleles, including the C580Y allele that has expanded to high frequencies under drug pressure in Southeast Asian resistant populations. Conclusions This optimized competitive growth assay can be employed for assessment of relative growth as an index of fitness during the asexual blood stage growth between natural lines carrying different genetic variants associated with artemisinin resistance. Improved understanding of the fitness costs of different parasites proliferating in human blood and the role different resistance mutations play in the context of specific genetic backgrounds will contribute to an understanding of the potential for specific mutations to spread in populations, with the potential to inform targeted strategies for malaria therapy.
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Affiliation(s)
- Abigail R Tirrell
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Katelyn M Vendrely
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Lisa A Checkley
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Sage Z Davis
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | | | | | | | - François H Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
| | | | - Michael T Ferdig
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA.
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13
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Gibbons J, Button-Simons KA, Adapa SR, Li S, Pietsch M, Zhang M, Liao X, Adams JH, Ferdig MT, Jiang RHY. Altered expression of K13 disrupts DNA replication and repair in Plasmodium falciparum. BMC Genomics 2018; 19:849. [PMID: 30486796 PMCID: PMC6263542 DOI: 10.1186/s12864-018-5207-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 10/30/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Plasmodium falciparum exhibits resistance to the artemisinin component of the frontline antimalarial treatment Artemisinin-based Combination Therapy in South East Asia. Millions of lives will be at risk if artemisinin resistance (ART-R) spreads to Africa. Single non-synonymous mutations in the propeller region of PF3D7_1343700,"K13" are implicated in resistance. In this work, we use transcriptional profiling to characterize a laboratory-generated k13 insertional mutant previously demonstrated to have increased sensitivity to artemisinins to explore the functional role of k13. RESULTS A set of RNA-seq and microarray experiments confirmed that the expression profile of k13 is specifically altered during the early ring and early trophozoite stages of the mutant intraerythrocytic development cycle. The down-regulation of k13 transcripts in this mutant during the early ring stage is associated with a transcriptome advance towards a more trophozoite-like state. To discover the specific downstream effect of k13 dysregulation, we developed a new computational method to search for differential gene expression while accounting for the temporal sequence of transcription. We found that the strongest biological signature of the transcriptome shift is an up-regulation of DNA replication and repair genes during the early ring developmental stage and a down-regulation of DNA replication and repair genes during the early trophozoite stage; by contrast, the expressions of housekeeping genes are unchanged. This effect, due to k13 dysregulation, is antagonistic, such that k13 levels are negatively correlated with DNA replication and repair gene expression. CONCLUSION Our results support a role for k13 as a stress response regulator consistent with the hypothesis that artemisinins mode of action is oxidative stress and k13 as a functional homolog of Keap1 which in humans regulates DNA replication and repair genes in response to oxidative stress.
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Affiliation(s)
- Justin Gibbons
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, USA.,Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, USA
| | - Katrina A Button-Simons
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, USA
| | - Swamy R Adapa
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, USA
| | - Suzanne Li
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, USA
| | - Maxwell Pietsch
- Department of Computer Science & Engineering, University of South Florida, Tampa, USA
| | - Min Zhang
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, USA
| | - Xiangyun Liao
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, USA
| | - John H Adams
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, USA
| | - Michael T Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, USA
| | - Rays H Y Jiang
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, USA.
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14
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Ghouila A, Siwo GH, Entfellner JBD, Panji S, Button-Simons KA, Davis SZ, Fadlelmola FM, Ferdig MT, Mulder N. Hackathons as a means of accelerating scientific discoveries and knowledge transfer. Genome Res 2018; 28:759-765. [PMID: 29650552 PMCID: PMC5932615 DOI: 10.1101/gr.228460.117] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 03/22/2018] [Indexed: 11/25/2022]
Abstract
Scientific research plays a key role in the advancement of human knowledge and pursuit of solutions to important societal challenges. Typically, research occurs within specific institutions where data are generated and subsequently analyzed. Although collaborative science bringing together multiple institutions is now common, in such collaborations the analytical processing of the data is often performed by individual researchers within the team, with only limited internal oversight and critical analysis of the workflow prior to publication. Here, we show how hackathons can be a means of enhancing collaborative science by enabling peer review before results of analyses are published by cross-validating the design of studies or underlying data sets and by driving reproducibility of scientific analyses. Traditionally, in data analysis processes, data generators and bioinformaticians are divided and do not collaborate on analyzing the data. Hackathons are a good strategy to build bridges over the traditional divide and are potentially a great agile extension to the more structured collaborations between multiple investigators and institutions.
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Affiliation(s)
- Amel Ghouila
- Institut Pasteur de Tunis, LR11IPT02, Laboratory of Transmission, Control and Immunobiology of Infections (LTCII), 1002 Tunis-Belvédère, Tunisia
| | - Geoffrey Henry Siwo
- IBM Research Africa, 2001, Johannesburg, South Africa.,Center for Research Computing, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Jean-Baka Domelevo Entfellner
- South African National Bioinformatics Institute/Medical Research Council of South Africa Bioinformatics Unit, University of the Western Cape, Bellville 7535, Cape Town, South Africa.,Computer Science Department, University of the Western Cape, Bellville 7535, Cape Town, South Africa
| | - Sumir Panji
- Computational Biology Division, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, 7925, Cape Town, South Africa
| | | | - Sage Zenon Davis
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Faisal M Fadlelmola
- Centre for Bioinformatics and Systems Biology, Faculty of Science, University of Khartoum, Khartoum 321, and Future University of Sudan, Khartoum, 10553, Sudan
| | | | - Michael T Ferdig
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Nicola Mulder
- Computational Biology Division, Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, 7925, Cape Town, South Africa
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15
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Turnbull LB, Siwo GH, Button-Simons KA, Tan A, Checkley LA, Painter HJ, Llinás M, Ferdig MT. Simultaneous genome-wide gene expression and transcript isoform profiling in the human malaria parasite. PLoS One 2017; 12:e0187595. [PMID: 29112986 PMCID: PMC5675406 DOI: 10.1371/journal.pone.0187595] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 10/23/2017] [Indexed: 12/22/2022] Open
Abstract
Gene expression DNA microarrays have been vital for characterizing whole-genome transcriptional profiles. Nevertheless, their effectiveness relies heavily on the accuracy of genome sequences, the annotation of gene structures, and the sequence-dependent performance of individual probes. Currently available gene expression arrays for the malaria parasite Plasmodium falciparum rely on an average of 2 probes per gene, usually positioned near the 3′ end of genes; consequently, existing designs are prone to measurement bias and cannot capture complexities such as the occurrence of transcript isoforms arising from alternative splicing or alternative start/ stop sites. Here, we describe two novel gene expression arrays with exon-focused probes designed with an average of 12 and 20 probes spanning each gene. This high probe density minimizes signal noise inherent in probe-to-probe sequence-dependent hybridization intensity. We demonstrate that these exon arrays accurately profile genome-wide expression, comparing favorably to currently available arrays and RNA-seq profiling, and can detect alternatively spliced transcript isoforms as well as non-coding RNAs (ncRNAs). Of the 964 candidate alternate splicing events from published RNA-seq studies, 162 are confirmed using the exon array. Furthermore, the exon array predicted 330 previously unidentified alternate splicing events. Gene expression microarrays continue to offer a cost-effective alternative to RNA-seq for the simultaneous monitoring of gene expression and alternative splicing events. Microarrays may even be preferred in some cases due to their affordability and the rapid turn-around of results when hundreds of samples are required for fine-scale systems biology investigations, including the monitoring of the networks of gene co-expression in the emergence of drug resistance.
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Affiliation(s)
- Lindsey B. Turnbull
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
- Ryan White Center for Pediatric Infectious Diseases and Global Health, Indiana University, Indianapolis, Indiana, United States of America
| | - Geoffrey H. Siwo
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
- IBM Research Africa, Johannesburg, South Africa
| | - Katrina A. Button-Simons
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Asako Tan
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
- Illumina, Madison, Wisconsin, United States of America
| | - Lisa A. Checkley
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Heather J. Painter
- Department of Biochemistry & Molecular Biology and Center for Malaria Research, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Manuel Llinás
- Department of Biochemistry & Molecular Biology and Center for Malaria Research, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Michael T. Ferdig
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
- * E-mail:
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16
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Rice DR, de Lourdes Betancourt Mendiola M, Murillo-Solano C, Checkley LA, Ferdig MT, Pizarro JC, Smith BD. Antiplasmodial activity of targeted zinc(II)-dipicolylamine complexes. Bioorg Med Chem 2017; 25:2754-2760. [PMID: 28377170 DOI: 10.1016/j.bmc.2017.03.050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 03/20/2017] [Accepted: 03/23/2017] [Indexed: 12/29/2022]
Abstract
This study measured the antiplasmodial activity of nine zinc-dipicolylamine (ZnDPA) complexes against three strains of Plasmodium falciparum, the causative parasite of malaria. Growth inhibition assays showed significant activity against all tested strains, with 50% inhibitory concentrations between 5 and 600nM and almost no toxic effect against host cells including healthy red blood cells. Fluorescence microscopy studies with a green-fluorescent ZnDPA probe showed selective targeting of infected red blood cells. The results suggest that ZnDPA coordination complexes are promising antiplasmodial agents with potential for targeted malaria treatment.
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Affiliation(s)
- Douglas R Rice
- Department of Chemistry and Biochemistry, 236 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556, USA
| | | | - Claribel Murillo-Solano
- Department of Tropical Medicine, J Bennett Johnston Building, 1430 Tulane Avenue, Tulane University, New Orleans, LA 70112, USA
| | - Lisa A Checkley
- Department of Biological Science, Galvin Life Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Michael T Ferdig
- Department of Biological Science, Galvin Life Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Juan C Pizarro
- Department of Tropical Medicine, J Bennett Johnston Building, 1430 Tulane Avenue, Tulane University, New Orleans, LA 70112, USA
| | - Bradley D Smith
- Department of Chemistry and Biochemistry, 236 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556, USA.
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17
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Siwo GH, Smith RS, Tan A, Button-Simons KA, Checkley LA, Ferdig MT. An integrative analysis of small molecule transcriptional responses in the human malaria parasite Plasmodium falciparum. BMC Genomics 2015; 16:1030. [PMID: 26637195 PMCID: PMC4670519 DOI: 10.1186/s12864-015-2165-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 10/29/2015] [Indexed: 12/05/2022] Open
Abstract
Background Transcriptional responses to small molecules can provide insights into drug mode of action (MOA). The capacity of the human malaria parasite, Plasmodium falciparum, to respond specifically to transcriptional perturbations has been unclear based on past approaches. Here, we present the most extensive profiling to date of the parasite’s transcriptional responsiveness to thirty-one chemically and functionally diverse small molecules. Methods We exposed two laboratory strains of the human malaria parasite P. falciparum to brief treatments of thirty-one chemically and functionally diverse small molecules associated with biological effects across multiple pathways based on various levels of evidence. We investigated the impact of chemical composition and MOA on gene expression similarities that arise between perturbations by various compounds. To determine the target biological pathways for each small molecule, we developed a novel framework for encoding small molecule effects on a spectra of biological processes or GO functions that are enriched in the differentially expressed genes of a given small molecule perturbation. Results We find that small molecules associated with similar transcriptional responses contain similar chemical features, and/ or have a shared MOA. The approach also revealed complex relationships between drugs and biological pathways that are missed by most exisiting approaches. For example, the approach was able to partition small molecule responses into drug-specific effects versus non-specific effects. Conclusions Our work provides a new framework for linking transcriptional responses to drug MOA in P. falciparum and can be generalized for the same purpose in other organisms. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2165-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Geoffrey H Siwo
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.,Current Address: IBM TJ Watson Research Center, Yorktown Heights, NY, 10598, USA.,Current Address: IBM Research-Africa, South Africa Lab, Sandton, Johannesburg, 2196, South Africa
| | - Roger S Smith
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.,Current Address: Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Asako Tan
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.,Epicenter, Madison, WI, 53719, USA
| | - Katrina A Button-Simons
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Lisa A Checkley
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Michael T Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.
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18
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Cheeseman IH, Miller B, Tan JC, Tan A, Nair S, Nkhoma SC, De Donato M, Rodulfo H, Dondorp A, Branch OH, Mesia LR, Newton P, Mayxay M, Amambua-Ngwa A, Conway DJ, Nosten F, Ferdig MT, Anderson TJC. Population Structure Shapes Copy Number Variation in Malaria Parasites. Mol Biol Evol 2015; 33:603-20. [PMID: 26613787 PMCID: PMC4760083 DOI: 10.1093/molbev/msv282] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
If copy number variants (CNVs) are predominantly deleterious, we would expect them to be more efficiently purged from populations with a large effective population size (Ne) than from populations with a small Ne. Malaria parasites (Plasmodium falciparum) provide an excellent organism to examine this prediction, because this protozoan shows a broad spectrum of population structures within a single species, with large, stable, outbred populations in Africa, small unstable inbred populations in South America and with intermediate population characteristics in South East Asia. We characterized 122 single-clone parasites, without prior laboratory culture, from malaria-infected patients in seven countries in Africa, South East Asia and South America using a high-density single-nucleotide polymorphism/CNV microarray. We scored 134 high-confidence CNVs across the parasite exome, including 33 deletions and 102 amplifications, which ranged in size from <500 bp to 59 kb, as well as 10,107 flanking, biallelic single-nucleotide polymorphisms. Overall, CNVs were rare, small, and skewed toward low frequency variants, consistent with the deleterious model. Relative to African and South East Asian populations, CNVs were significantly more common in South America, showed significantly less skew in allele frequencies, and were significantly larger. On this background of low frequency CNV, we also identified several high-frequency CNVs under putative positive selection using an FST outlier analysis. These included known adaptive CNVs containing rh2b and pfmdr1, and several other CNVs (e.g., DNA helicase and three conserved proteins) that require further investigation. Our data are consistent with a significant impact of genetic structure on CNV burden in an important human pathogen.
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Affiliation(s)
- Ian H Cheeseman
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX
| | - Becky Miller
- The Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame
| | - John C Tan
- The Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame
| | - Asako Tan
- The Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame
| | - Shalini Nair
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX
| | - Standwell C Nkhoma
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi
| | - Marcos De Donato
- Lab. Genetica Molecular, IIBCAUDO, Universidad De Oriente, Cumana, Venezuela
| | - Hectorina Rodulfo
- Lab. Genetica Molecular, IIBCAUDO, Universidad De Oriente, Cumana, Venezuela
| | - Arjen Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, University of Oxford, Oxford, United Kingdom
| | - Oralee H Branch
- Division of Parasitology, Department of Microbiology, New York University School of Medicine
| | - Lastenia Ruiz Mesia
- Laboratorio De Investigaciones De Productos Naturales Y Antiparasitarios, Universidad Nacional De La Amazonia Peruana, Iquitos, Peru
| | - Paul Newton
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, University of Oxford, Oxford, United Kingdom Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Mayfong Mayxay
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, University of Oxford, Oxford, United Kingdom Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR Faculty of Postgraduate Studies, University of Health Sciences, Vientiane, Lao PDR
| | | | - David J Conway
- Medical Research Council Unit, Fajara, Banjul, The Gambia Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - François Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, University of Oxford, Oxford, United Kingdom Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Michael T Ferdig
- The Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame
| | - Tim J C Anderson
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX
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19
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Vaughan AM, Pinapati RS, Cheeseman IH, Camargo N, Fishbaugher M, Checkley LA, Nair S, Hutyra CA, Nosten FH, Anderson TJC, Ferdig MT, Kappe SHI. Plasmodium falciparum genetic crosses in a humanized mouse model. Nat Methods 2015; 12:631-3. [PMID: 26030447 PMCID: PMC4547688 DOI: 10.1038/nmeth.3432] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 04/21/2015] [Indexed: 12/30/2022]
Abstract
Genetic crosses of phenotypically distinct strains of the human malaria parasite Plasmodium falciparum are a powerful tool for identifying genes controlling drug resistance and other key phenotypes. Previous studies relied on the isolation of recombinant parasites from splenectomized chimpanzees, a research avenue that is no longer available. Here we demonstrate that human-liver chimeric mice support recovery of recombinant progeny for the identification of genetic determinants of parasite traits and adaptations.
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Affiliation(s)
| | - Richard S. Pinapati
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | | | - Nelly Camargo
- Seattle Biomedical Research Institute, Seattle, Washington, USA
| | | | - Lisa A. Checkley
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Shalini Nair
- Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Carolyn A. Hutyra
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - François H. Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot, Thailand
| | | | - Michael T. Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Stefan H. I. Kappe
- Seattle Biomedical Research Institute, Seattle, Washington, USA
- Department of Global Health, University of Washington, Seattle, Washington, USA
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20
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Merrick CJ, Jiang RHY, Skillman KM, Samarakoon U, Moore RM, Dzikowski R, Ferdig MT, Duraisingh MT. Functional analysis of sirtuin genes in multiple Plasmodium falciparum strains. PLoS One 2015; 10:e0118865. [PMID: 25780929 PMCID: PMC4364008 DOI: 10.1371/journal.pone.0118865] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 01/07/2015] [Indexed: 12/22/2022] Open
Abstract
Plasmodium falciparum, the causative agent of severe human malaria, employs antigenic variation to avoid host immunity. Antigenic variation is achieved by transcriptional switching amongst polymorphic var genes, enforced by epigenetic modification of chromatin. The histone-modifying 'sirtuin' enzymes PfSir2a and PfSir2b have been implicated in this process. Disparate patterns of var expression have been reported in patient isolates as well as in cultured strains. We examined var expression in three commonly used laboratory strains (3D7, NF54 and FCR-3) in parallel. NF54 parasites express significantly lower levels of var genes compared to 3D7, despite the fact that 3D7 was originally a clone of the NF54 strain. To investigate whether this was linked to the expression of sirtuins, genetic disruption of both sirtuins was attempted in all three strains. No dramatic changes in var gene expression occurred in NF54 or FCR-3 following PfSir2b disruption, contrasting with previous observations in 3D7. In 3D7, complementation of the PfSir2a genetic disruption resulted in a significant decrease in previously-elevated var gene expression levels, but with the continued expression of multiple var genes. Finally, rearranged chromosomes were observed in the 3D7 PfSir2a knockout line. Our results focus on the potential for parasite genetic background to contribute to sirtuin function in regulating virulence gene expression and suggest a potential role for sirtuins in maintaining genome integrity.
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Affiliation(s)
- Catherine J. Merrick
- Department of Immunology & Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Rays H. Y. Jiang
- Department of Immunology & Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Kristen M. Skillman
- Department of Immunology & Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Upeka Samarakoon
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Rachel M. Moore
- Department of Immunology & Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Ron Dzikowski
- Department of Microbiology & Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Michael T. Ferdig
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Manoj T. Duraisingh
- Department of Immunology & Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
- * E-mail:
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21
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Siwo GH, Tan A, Button-Simons KA, Samarakoon U, Checkley LA, Pinapati RS, Ferdig MT. Predicting functional and regulatory divergence of a drug resistance transporter gene in the human malaria parasite. BMC Genomics 2015; 16:115. [PMID: 25765049 PMCID: PMC4352545 DOI: 10.1186/s12864-015-1261-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 01/22/2015] [Indexed: 12/05/2022] Open
Abstract
Background The paradigm of resistance evolution to chemotherapeutic agents is that a key coding mutation in a specific gene drives resistance to a particular drug. In the case of resistance to the anti-malarial drug chloroquine (CQ), a specific mutation in the transporter pfcrt is associated with resistance. Here, we apply a series of analytical steps to gene expression data from our lab and leverage 3 independent datasets to identify pfcrt-interacting genes. Resulting networks provide insights into pfcrt’s biological functions and regulation, as well as the divergent phenotypic effects of its allelic variants in different genetic backgrounds. Results To identify pfcrt-interacting genes, we analyze pfcrt co-expression networks in 2 phenotypic states - CQ-resistant (CQR) and CQ-sensitive (CQS) recombinant progeny clones - using a computational approach that prioritizes gene interactions into functional and regulatory relationships. For both phenotypic states, pfcrt co-expressed gene sets are associated with hemoglobin metabolism, consistent with CQ’s expected mode of action. To predict the drivers of co-expression divergence, we integrate topological relationships in the co-expression networks with available high confidence protein-protein interaction data. This analysis identifies 3 transcriptional regulators from the ApiAP2 family and histone acetylation as potential mediators of these divergences. We validate the predicted divergences in DNA mismatch repair and histone acetylation by measuring the effects of small molecule inhibitors in recombinant progeny clones combined with quantitative trait locus (QTL) mapping. Conclusions This work demonstrates the utility of differential co-expression viewed in a network framework to uncover functional and regulatory divergence in phenotypically distinct parasites. pfcrt-associated co-expression in the CQ resistant progeny highlights CQR-specific gene relationships and possible targeted intervention strategies. The approaches outlined here can be readily generalized to other parasite populations and drug resistances. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1261-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Geoffrey H Siwo
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA. .,Geisel School of Medicine, Dartmouth College, Hanover, NH, USA.
| | - Asako Tan
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA. .,Epicentre, Madison, WI, USA.
| | - Katrina A Button-Simons
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA.
| | - Upeka Samarakoon
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA. .,Harvard Medical School, Boston, MA, USA.
| | - Lisa A Checkley
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA.
| | - Richard S Pinapati
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA.
| | - Michael T Ferdig
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA.
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Takala-Harrison S, Jacob CG, Arze C, Cummings MP, Silva JC, Dondorp AM, Fukuda MM, Hien TT, Mayxay M, Noedl H, Nosten F, Kyaw MP, Nhien NTT, Imwong M, Bethell D, Se Y, Lon C, Tyner SD, Saunders DL, Ariey F, Mercereau-Puijalon O, Menard D, Newton PN, Khanthavong M, Hongvanthong B, Starzengruber P, Fuehrer HP, Swoboda P, Khan WA, Phyo AP, Nyunt MM, Nyunt MH, Brown TS, Adams M, Pepin CS, Bailey J, Tan JC, Ferdig MT, Clark TG, Miotto O, MacInnis B, Kwiatkowski DP, White NJ, Ringwald P, Plowe CV. Independent emergence of artemisinin resistance mutations among Plasmodium falciparum in Southeast Asia. J Infect Dis 2014; 211:670-9. [PMID: 25180241 DOI: 10.1093/infdis/jiu491] [Citation(s) in RCA: 325] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The emergence of artemisinin-resistant Plasmodium falciparum in Southeast Asia threatens malaria treatment efficacy. Mutations in a kelch protein encoded on P. falciparum chromosome 13 (K13) have been associated with resistance in vitro and in field samples from Cambodia. METHODS P. falciparum infections from artesunate efficacy trials in Bangladesh, Cambodia, Laos, Myanmar, and Vietnam were genotyped at 33 716 genome-wide single-nucleotide polymorphisms (SNPs). Linear mixed models were used to test associations between parasite genotypes and parasite clearance half-lives following artesunate treatment. K13 mutations were tested for association with artemisinin resistance, and extended haplotypes on chromosome 13 were examined to determine whether mutations arose focally and spread or whether they emerged independently. RESULTS The presence of nonreference K13 alleles was associated with prolonged parasite clearance half-life (P = 1.97 × 10(-12)). Parasites with a mutation in any of the K13 kelch domains displayed longer parasite clearance half-lives than parasites with wild-type alleles. Haplotype analysis revealed both population-specific emergence of mutations and independent emergence of the same mutation in different geographic areas. CONCLUSIONS K13 appears to be a major determinant of artemisinin resistance throughout Southeast Asia. While we found some evidence of spreading resistance, there was no evidence of resistance moving westward from Cambodia into Myanmar.
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Affiliation(s)
| | | | - Cesar Arze
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore
| | - Michael P Cummings
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore
| | | | - Mark M Fukuda
- Armed Forces Research Institute of Medical Sciences, Bangkok
| | - Tran Tinh Hien
- Center for Tropical Medicine, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Mayfong Mayxay
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital Faculty of Postgraduate Studies, University of Health Sciences Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford
| | - Harald Noedl
- Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Austria
| | - Francois Nosten
- Mahidol-Oxford Tropical Medicine Research Unit Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford
| | - Myat P Kyaw
- Department of Medical Research (Lower Myanmar), Yangon
| | - Nguyen Thanh Thuy Nhien
- Center for Tropical Medicine, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University
| | - Delia Bethell
- Armed Forces Research Institute of Medical Sciences, Bangkok
| | - Youry Se
- Armed Forces Research Institute of Medical Sciences
| | - Chanthap Lon
- Armed Forces Research Institute of Medical Sciences
| | - Stuart D Tyner
- Armed Forces Research Institute of Medical Sciences, Bangkok
| | | | | | | | - Didier Menard
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Paul N Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford
| | | | | | - Peter Starzengruber
- Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Austria
| | - Hans-Peter Fuehrer
- Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Austria
| | - Paul Swoboda
- Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Austria
| | - Wasif A Khan
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - Aung Pyae Phyo
- Mahidol-Oxford Tropical Medicine Research Unit Shoklo Malaria Research Unit Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Myaing M Nyunt
- Howard Hughes Medical Institute/Center for Vaccine Development
| | - Myat H Nyunt
- Department of Medical Research (Lower Myanmar), Yangon
| | - Tyler S Brown
- Howard Hughes Medical Institute/Center for Vaccine Development
| | - Matthew Adams
- Howard Hughes Medical Institute/Center for Vaccine Development
| | | | - Jason Bailey
- Howard Hughes Medical Institute/Center for Vaccine Development
| | - John C Tan
- Research and Development, Roche NimbleGen, Madison, Wisconsin
| | - Michael T Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Indiana
| | - Taane G Clark
- Faculty of Epidemiology and Population Health Faculty Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine
| | - Olivo Miotto
- Mahidol-Oxford Tropical Medicine Research Unit MRC Centre for Genomics and Global Health, Oxford University and Wellcome Trust Sanger Institute Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Bronwyn MacInnis
- Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Dominic P Kwiatkowski
- MRC Centre for Genomics and Global Health, Oxford University and Wellcome Trust Sanger Institute Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | | | - Pascal Ringwald
- Drug Resistance and Containment Unit, Global Malaria Programme, World Health Organization, Geneva, Switzerland
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Jacob CG, Tan JC, Miller BA, Tan A, Takala-Harrison S, Ferdig MT, Plowe CV. A microarray platform and novel SNP calling algorithm to evaluate Plasmodium falciparum field samples of low DNA quantity. BMC Genomics 2014; 15:719. [PMID: 25159520 PMCID: PMC4153902 DOI: 10.1186/1471-2164-15-719] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 08/11/2014] [Indexed: 01/07/2023] Open
Abstract
Background Analysis of single nucleotide polymorphisms (SNPs) derived from whole-genome studies allows for rapid evaluation of genome-wide diversity, and genomic epidemiology studies of Plasmodium falciparum provide insights into parasite population structure, gene flow, drug resistance and vaccine development. In areas with adequate cold chain facilities, large volumes of leukocyte-depleted patient blood can be frozen for use in parasite genomic analyses. In more remote endemic areas smaller volumes of infected blood are taken by finger prick, and dried and stored on filter paper. These dried blood spots do not generally yield enough concentrated parasite DNA for whole-genome sequencing. Results A DNA microarray was designed for use on field samples to type a genome-wide set of SNPs which prior sequencing had shown to be variable in Africa, Southeast Asia, and Papua New Guinea. An algorithm was designed to call SNPs in samples with low parasite DNA. With this new algorithm SNP-calling accuracy of 98% was measured by hybridizing purified DNA from malaria lab strains and comparing calls with SNPs called from full genome sequences. An average accuracy of >98% was likewise obtained for DNA extracted from malaria field samples collected in studies in Southeast Asia, with an average call rate of > 82%. Conclusion This new high-density microarray provided high quality SNP calls from a wide range of parasite DNA quantities, and represents a robust tool for genome-wide analysis of malaria parasites in diverse settings.
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Affiliation(s)
| | | | | | | | | | | | - Christopher V Plowe
- Malaria Group, Howard Hughes Medical Institute / Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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24
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Sanchez CP, Liu CH, Mayer S, Nurhasanah A, Cyrklaff M, Mu J, Ferdig MT, Stein WD, Lanzer M. A HECT ubiquitin-protein ligase as a novel candidate gene for altered quinine and quinidine responses in Plasmodium falciparum. PLoS Genet 2014; 10:e1004382. [PMID: 24830312 PMCID: PMC4022464 DOI: 10.1371/journal.pgen.1004382] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 04/01/2014] [Indexed: 11/18/2022] Open
Abstract
The emerging resistance to quinine jeopardizes the efficacy of a drug that has been used in the treatment of malaria for several centuries. To identify factors contributing to differential quinine responses in the human malaria parasite Plasmodium falciparum, we have conducted comparative quantitative trait locus analyses on the susceptibility to quinine and also its stereoisomer quinidine, and on the initial and steady-state intracellular drug accumulation levels in the F1 progeny of a genetic cross. These data, together with genetic screens of field isolates and laboratory strains associated differential quinine and quinidine responses with mutated pfcrt, a segment on chromosome 13, and a novel candidate gene, termed MAL7P1.19 (encoding a HECT ubiquitin ligase). Despite a strong likelihood of association, episomal transfections demonstrated a role for the HECT ubiquitin-protein ligase in quinine and quinidine sensitivity in only a subset of genetic backgrounds, and here the changes in IC50 values were moderate (approximately 2-fold). These data show that quinine responsiveness is a complex genetic trait with multiple alleles playing a role and that more experiments are needed to unravel the role of the contributing factors. Quinine, a natural product from cinchona bark, has been used in the treatment of malaria for centuries. Unfortunately, a progressive loss in responsiveness of the human malaria parasite Plasmodium falciparum to quinine has been observed, particularly in Southeast Asia, where cases of quinine treatment failure regularly occur. To better understand how P. falciparum defends itself against the cytotoxic activity of quinine, we have conducted comparative linkage analyses in the F1 progeny of a genetic cross where we assessed the susceptibility and the amount of intracellular accumulation of quinine and of its stereoisomer quinidine. These data identified a novel candidate gene encoding a HECT ubiquitin-protein ligase that might contribute to altered quinine responsiveness. The identification of this novel gene might improve the surveillance of quinine-resistant malaria parasites in the field and aid the preservation of this valuable antimalarial drug.
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Affiliation(s)
- Cecilia P. Sanchez
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - Chia-Hao Liu
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - Sybille Mayer
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - Astutiati Nurhasanah
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
- Laboratory for the Development of Agroindustrial and Biomedical Technology (LAPTIAB), Tangerang Selatan, Indonesia
| | - Marek Cyrklaff
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - Jianbing Mu
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, United States of America
| | - Michael T. Ferdig
- The Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Wilfred D. Stein
- Biological Chemistry, Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
| | - Michael Lanzer
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
- * E-mail:
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Lewis IA, Wacker M, Olszewski KL, Cobbold SA, Baska KS, Tan A, Ferdig MT, Llinás M. Metabolic QTL analysis links chloroquine resistance in Plasmodium falciparum to impaired hemoglobin catabolism. PLoS Genet 2014; 10:e1004085. [PMID: 24391526 PMCID: PMC3879234 DOI: 10.1371/journal.pgen.1004085] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 11/19/2013] [Indexed: 11/29/2022] Open
Abstract
Drug resistant strains of the malaria parasite, Plasmodium falciparum, have rendered chloroquine ineffective throughout much of the world. In parts of Africa and Asia, the coordinated shift from chloroquine to other drugs has resulted in the near disappearance of chloroquine-resistant (CQR) parasites from the population. Currently, there is no molecular explanation for this phenomenon. Herein, we employ metabolic quantitative trait locus mapping (mQTL) to analyze progeny from a genetic cross between chloroquine-susceptible (CQS) and CQR parasites. We identify a family of hemoglobin-derived peptides that are elevated in CQR parasites and show that peptide accumulation, drug resistance, and reduced parasite fitness are all linked in vitro to CQR alleles of the P. falciparum chloroquine resistance transporter (pfcrt). These findings suggest that CQR parasites are less fit because mutations in pfcrt interfere with hemoglobin digestion by the parasite. Moreover, our findings may provide a molecular explanation for the reemergence of CQS parasites in wild populations. Chloroquine was formerly a front line drug in the treatment of malaria. However, drug resistant strains of the malaria parasite have made this drug ineffective in many malaria endemic regions. Surprisingly, the discontinuation of chloroquine therapy has led to the reappearance of drug-sensitive parasites. In this study, we use metabolite quantitative trait locus analysis, parasite genetics, and peptidomics to demonstrate that chloroquine resistance is inherently linked to a defect in the parasite's ability to digest hemoglobin, which is an essential metabolic activity for malaria parasites. This metabolic impairment makes it harder for the drug-resistant parasites to reproduce than genetically-equivalent drug-sensitive parasites, and thus favors selection for drug-sensitive lines when parasites are in direct competition. Given these results, we attribute the re-emergence of chloroquine sensitive parasites in the wild to more efficient hemoglobin digestion.
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Affiliation(s)
- Ian A. Lewis
- Department of Molecular Biology and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Mark Wacker
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Kellen L. Olszewski
- Department of Molecular Biology and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Simon A. Cobbold
- Department of Molecular Biology and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Katelynn S. Baska
- Department of Molecular Biology and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Asako Tan
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Michael T. Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
- * E-mail: (MTF); (ML)
| | - Manuel Llinás
- Department of Molecular Biology and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- * E-mail: (MTF); (ML)
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Rider AK, Siwo G, Emrich SJ, Ferdig MT, Chawla NV. A supervised learning approach to the ensemble clustering of genes. INT J DATA MIN BIOIN 2014; 9:199-219. [DOI: 10.1504/ijdmb.2014.059062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Heinberg A, Siu E, Stern C, Lawrence EA, Ferdig MT, Deitsch KW, Kirkman LA. Direct evidence for the adaptive role of copy number variation on antifolate susceptibility in Plasmodium falciparum. Mol Microbiol 2013; 88:702-12. [PMID: 23347134 DOI: 10.1111/mmi.12162] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2013] [Indexed: 11/29/2022]
Abstract
Resistance to antimalarials targeting the folate pathway is widespread. GTP-cyclohydrolase (gch1), the first enzyme in this pathway, exhibits extensive copy number variation (CN) in parasite isolates from areas with a history of longstanding antifolate use. Increased CN of gch1 is associated with a greater number of point mutations in enzymes targeted by the antifolates, pyrimethamine and sulphadoxine. While these observations suggest that increases in gch1 CN are an adaptation to drug pressure, changes in CN have not been experimentally demonstrated to directly alter drug susceptibility. To determine if changes in gch1 expression alone modify pyrimethamine sensitivity, we manipulated gch1 CN in several parasite lines to test the effect on drug sensitivity. We report that increases in gch1 CN alter pyrimethamine resistance in most parasites lines. However we find evidence of a detrimental effect of very high levels of gch1 overexpression in parasite lines with high endogenous levels of gch1 expression, revealing the importance of maintaining balance in the folate pathway and implicating changes in gch1 expression in preserving proper metabolic flux. This work expands our understanding of parasite adaptation to drug pressure and provides a possible mechanism for how specific mutations become fixed within parasite populations.
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Affiliation(s)
- Adina Heinberg
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA
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Griffin CE, Hoke JM, Samarakoon U, Duan J, Mu J, Ferdig MT, Warhurst DC, Cooper RA. Mutation in the Plasmodium falciparum CRT protein determines the stereospecific activity of antimalarial cinchona alkaloids. Antimicrob Agents Chemother 2012; 56:5356-64. [PMID: 22869567 PMCID: PMC3457399 DOI: 10.1128/aac.05667-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 07/30/2012] [Indexed: 11/20/2022] Open
Abstract
The Cinchona alkaloids are quinoline aminoalcohols that occur as diastereomer pairs, typified by (-)-quinine and (+)-quinidine. The potency of (+)-isomers is greater than the (-)-isomers in vitro and in vivo against Plasmodium falciparum malaria parasites. They may act by the inhibition of heme crystallization within the parasite digestive vacuole in a manner similar to chloroquine. Earlier studies showed that a K76I mutation in the digestive vacuole-associated protein, PfCRT (P. falciparum chloroquine resistance transporter), reversed the normal potency order of quinine and quinidine toward P. falciparum. To further explore PfCRT-alkaloid interactions in the malaria parasite, we measured the in vitro susceptibility of eight clonal lines of P. falciparum derived from the 106/1 strain, each containing a unique pfcrt allele, to four Cinchona stereoisomer pairs: quinine and quinidine; cinchonidine and cinchonine; hydroquinine and hydroquinidine; 9-epiquinine and 9-epiquinidine. Stereospecific potency of the Cinchona alkaloids was associated with changes in charge and hydrophobicity of mutable PfCRT amino acids. In isogenic chloroquine-resistant lines, the IC(50) ratio of (-)/(+) CA pairs correlated with side chain hydrophobicity of the position 76 residue. Second-site PfCRT mutations negated the K76I stereospecific effects: charge-change mutations C72R or Q352K/R restored potency patterns similar to the parent K76 line, while V369F increased susceptibility to the alkaloids and nullified stereospecific differences between alkaloid pairs. Interactions between key residues of the PfCRT channel/transporter with (-) and (+) alkaloids are stereospecifically determined, suggesting that PfCRT binding plays an important role in the antimalarial activity of quinine and other Cinchona alkaloids.
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Affiliation(s)
- Carol E. Griffin
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, USA
| | - Jonathan M. Hoke
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, USA
| | - Upeka Samarakoon
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, South Bend, Indiana, USA
| | - Junhui Duan
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Jianbing Mu
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Michael T. Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, South Bend, Indiana, USA
| | - David C. Warhurst
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Roland A. Cooper
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, USA
- Department of Natural Sciences and Mathematics, Dominican University of California, San Rafael, California, USA
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Manske M, Miotto O, Campino S, Auburn S, Almagro-Garcia J, Maslen G, O'Brien J, Djimde A, Doumbo O, Zongo I, Ouedraogo JB, Michon P, Mueller I, Siba P, Nzila A, Borrmann S, Kiara SM, Marsh K, Jiang H, Su XZ, Amaratunga C, Fairhurst R, Socheat D, Nosten F, Imwong M, White NJ, Sanders M, Anastasi E, Alcock D, Drury E, Oyola S, Quail MA, Turner DJ, Ruano-Rubio V, Jyothi D, Amenga-Etego L, Hubbart C, Jeffreys A, Rowlands K, Sutherland C, Roper C, Mangano V, Modiano D, Tan JC, Ferdig MT, Amambua-Ngwa A, Conway DJ, Takala-Harrison S, Plowe CV, Rayner JC, Rockett KA, Clark TG, Newbold CI, Berriman M, MacInnis B, Kwiatkowski DP. Analysis of Plasmodium falciparum diversity in natural infections by deep sequencing. Nature 2012; 487:375-9. [PMID: 22722859 PMCID: PMC3738909 DOI: 10.1038/nature11174] [Citation(s) in RCA: 384] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Accepted: 04/30/2012] [Indexed: 02/02/2023]
Abstract
Malaria elimination strategies require surveillance of the parasite population for genetic changes that demand a public health response, such as new forms of drug resistance. Here we describe methods for the large-scale analysis of genetic variation in Plasmodium falciparum by deep sequencing of parasite DNA obtained from the blood of patients with malaria, either directly or after short-term culture. Analysis of 86,158 exonic single nucleotide polymorphisms that passed genotyping quality control in 227 samples from Africa, Asia and Oceania provides genome-wide estimates of allele frequency distribution, population structure and linkage disequilibrium. By comparing the genetic diversity of individual infections with that of the local parasite population, we derive a metric of within-host diversity that is related to the level of inbreeding in the population. An open-access web application has been established for the exploration of regional differences in allele frequency and of highly differentiated loci in the P. falciparum genome.
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Affiliation(s)
- Magnus Manske
- Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
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Wacker MA, Turnbull LB, Walker LA, Mount MC, Ferdig MT. Quantification of multiple infections of Plasmodium falciparum in vitro. Malar J 2012; 11:180. [PMID: 22646748 PMCID: PMC3483182 DOI: 10.1186/1475-2875-11-180] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 03/13/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Human malaria infections caused by the parasite Plasmodium falciparum often contain more than one genetically distinct parasite. Despite this fact, nearly all studies of multiple strain P. falciparum infections have been limited to determining relative densities of each parasite within an infection. In light of this, new methods are needed that can quantify the absolute number of parasites within a single infection. METHODS A quantitative PCR (qPCR) method was developed to track the dynamic interaction of P. falciparum infections containing genetically distinct parasite clones in cultured red blood cells. Allele-specific primers were used to generate a standard curve and to quantify the absolute concentration of parasite DNA within multi-clonal infections. Effects on dynamic growth relationships between parasites under drug pressure were examined by treating mixed cultures of drug sensitive and drug resistant parasites with the anti-malarial drug chloroquine at different dosing schedules. RESULTS An absolute quantification method was developed to monitor the dynamics of P. falciparum cultures in vitro. This method allowed for the observation of competitive suppression, the reduction of parasites numbers due to the presence of another parasite, and competitive release, the improved performance of a parasite after the removal of a competitor. These studies demonstrated that the presence of two parasites led to the reduction in density of at least one parasite. The introduction of drug to a mixed culture containing both a drug resistant and drug sensitive parasites resulted in an increased proportion of the drug resistant parasite. Moreover, following drug treatment, the resistant parasite experienced competitive release by exhibiting a fitness benefit greater than simply surviving drug treatment, due to the removal of competitive suppression by the sensitive parasite. CONCLUSIONS The newly developed assay allowed for the examination of the dynamics of two distinct clones in vitro; both competitive suppression and release were observed. A deeper understanding of the dynamic growth responses of multiple strain P. falciparum infections, with and without drug pressure, can improve the understanding of the role of parasite interactions in the spread of drug resistant parasites, perhaps suggesting different treatment strategies.
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Affiliation(s)
- Mark A Wacker
- Eck Institute of Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
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31
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Cheeseman IH, Miller BA, Nair S, Nkhoma S, Tan A, Tan JC, Al Saai S, Phyo AP, Moo CL, Lwin KM, McGready R, Ashley E, Imwong M, Stepniewska K, Yi P, Dondorp AM, Mayxay M, Newton PN, White NJ, Nosten F, Ferdig MT, Anderson TJC. A major genome region underlying artemisinin resistance in malaria. Science 2012; 336:79-82. [PMID: 22491853 DOI: 10.1126/science.1215966] [Citation(s) in RCA: 314] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Evolving resistance to artemisinin-based compounds threatens to derail attempts to control malaria. Resistance has been confirmed in western Cambodia and has recently emerged in western Thailand, but is absent from neighboring Laos. Artemisinin resistance results in reduced parasite clearance rates (CRs) after treatment. We used a two-phase strategy to identify genome region(s) underlying this ongoing selective event. Geographical differentiation and haplotype structure at 6969 polymorphic single-nucleotide polymorphisms (SNPs) in 91 parasites from Cambodia, Thailand, and Laos identified 33 genome regions under strong selection. We screened SNPs and microsatellites within these regions in 715 parasites from Thailand, identifying a selective sweep on chromosome 13 that shows strong association (P = 10(-6) to 10(-12)) with slow CRs, illustrating the efficacy of targeted association for identifying the genetic basis of adaptive traits.
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Affiliation(s)
- Ian H Cheeseman
- Texas Biomedical Research Institute, San Antonio, TX 78245, USA
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Huang Y, Siwo G, Wuchty S, Ferdig MT, Przytycka TM. Symmetric Epistasis Estimation (SEE) and its application to dissecting interaction map of Plasmodium falciparum. Mol Biosyst 2012; 8:1544-52. [PMID: 22419061 DOI: 10.1039/c2mb05333k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
It is being increasingly recognized that many important phenotypic traits, including various diseases, are governed by a combination of weak genetic effects and their interactions. While the detection of epistatic interactions that involve a non-additive effect of two loci on a quantitative trait is particularly challenging, this interaction type is fundamental for the understanding of genome organization and gene regulation. However, current methods that detect epistatic interactions typically rely on the existence of a strong primary effect, considerably limiting the sensitivity of the search. To fill this gap, we developed a new method, SEE (Symmetric Epistasis Estimation), allowing the genome-wide detection of epistatic interactions without the need for a strong primary effect. We applied our approach to progeny crosses of the human malaria parasite P. falciparum and S. cerevisiae. We found an abundance of epistatic interactions in the parasite and a much smaller number of such interactions in yeast. The genome of P. falciparum also harboured several epistatic interaction hotspots that putatively play a role in drug resistance mechanisms. The abundance of observed epistatic interactions might suggest a mechanism of compensation for the extremely limited repertoire of transcription factors. Interestingly, epistatic interaction hotspots were associated with elevated levels of linkage disequilibrium, an observation that suggests selection pressure acting on P. falciparum, potentially reflecting host-pathogen interactions or drug-induced selection.
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Affiliation(s)
- Yang Huang
- National Center for Biotechnology Information, NLM, NIH, 8600 Rockville Pike, Building 38A, Bethesda, MD 20894, USA
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Samarakoon U, Gonzales JM, Patel JJ, Tan A, Checkley L, Ferdig MT. The landscape of inherited and de novo copy number variants in a Plasmodium falciparum genetic cross. BMC Genomics 2011; 12:457. [PMID: 21936954 PMCID: PMC3191341 DOI: 10.1186/1471-2164-12-457] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Accepted: 09/22/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Copy number is a major source of genome variation with important evolutionary implications. Consequently, it is essential to determine copy number variant (CNV) behavior, distributions and frequencies across genomes to understand their origins in both evolutionary and generational time frames. We use comparative genomic hybridization (CGH) microarray and the resolution provided by a segregating population of cloned progeny lines of the malaria parasite, Plasmodium falciparum, to identify and analyze the inheritance of 170 genome-wide CNVs. RESULTS We describe CNVs in progeny clones derived from both Mendelian (i.e. inherited) and non-Mendelian mechanisms. Forty-five CNVs were present in the parent lines and segregated in the progeny population. Furthermore, extensive variation that did not conform to strict Mendelian inheritance patterns was observed. 124 CNVs were called in one or more progeny but in neither parent: we observed CNVs in more than one progeny clone that were not identified in either parent, located more frequently in the telomeric-subtelomeric regions of chromosomes and singleton de novo CNVs distributed evenly throughout the genome. Linkage analysis of CNVs revealed dynamic copy number fluctuations and suggested mechanisms that could have generated them. Five of 12 previously identified expression quantitative trait loci (eQTL) hotspots coincide with CNVs, demonstrating the potential for broad influence of CNV on the transcriptional program and phenotypic variation. CONCLUSIONS CNVs are a significant source of segregating and de novo genome variation involving hundreds of genes. Examination of progeny genome segments provides a framework to assess the extent and possible origins of CNVs. This segregating genetic system reveals the breadth, distribution and dynamics of CNVs in a surprisingly plastic parasite genome, providing a new perspective on the sources of diversity in parasite populations.
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Affiliation(s)
- Upeka Samarakoon
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556, USA
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Wuchty S, Siwo GH, Ferdig MT. Shared molecular strategies of the malaria parasite P. falciparum and the human virus HIV-1. Mol Cell Proteomics 2011; 10:M111.009035. [PMID: 21586753 DOI: 10.1074/mcp.m111.009035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We augmented existing computationally predicted and experimentally determined interactions with evolutionarily conserved interactions between proteins of the malaria parasite, P. falciparum, and the human host. In a validation step, we found that conserved interacting host-parasite protein pairs were specifically expressed in host tissues where both the parasite and host proteins are known to be active. We compared host-parasite interactions with experimentally verified interactions between human host proteins and a very different pathogen, HIV-1. Both pathogens were found to use their protein repertoire in a combinatorial manner, providing a broad connection to host cellular processes. Specifically, the two biologically distinct pathogens predominately target central proteins to take control of a human host cell, effectively reaching into diversified cellular host cellular functions. Interacting signaling pathways and a small set of regulatory and signaling proteins were prime targets of both pathogens, suggesting remarkably similar patterns of host-pathogen interactions despite the vast biological differences of both pathogens. Such an identification of shared molecular strategies by the virus HIV-1 and the eukaryotic intracellular pathogen P. falciparum may allow us to illuminate new avenues of disease intervention.
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Affiliation(s)
- Stefan Wuchty
- National Center of Biotechnology Information, National Institutes of Health, Bethesda, MD 20892, USA.
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35
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Tan JC, Miller BA, Tan A, Patel JJ, Cheeseman IH, Anderson TJC, Manske M, Maslen G, Kwiatkowski DP, Ferdig MT. An optimized microarray platform for assaying genomic variation in Plasmodium falciparum field populations. Genome Biol 2011; 12:R35. [PMID: 21477297 PMCID: PMC3218861 DOI: 10.1186/gb-2011-12-4-r35] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 03/04/2011] [Accepted: 04/08/2011] [Indexed: 11/13/2022] Open
Abstract
We present an optimized probe design for copy number variation (CNV) and SNP genotyping in the Plasmodium falciparum genome. We demonstrate that variable length and isothermal probes are superior to static length probes. We show that sample preparation and hybridization conditions mitigate the effects of host DNA contamination in field samples. The microarray and workflow presented can be used to identify CNVs and SNPs with 95% accuracy in a single hybridization, in field samples containing up to 92% human DNA contamination.
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Affiliation(s)
- John C Tan
- The Eck Institute for Global Health, University of Notre Dame, 100 Galvin Life Sciences, Notre Dame, IN 46556, USA
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36
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Miller MJ, Walz AJ, Zhu H, Wu C, Moraski G, Möllmann U, Tristani EM, Crumbliss AL, Ferdig MT, Checkley L, Edwards RL, Boshoff HI. Design, synthesis, and study of a mycobactin-artemisinin conjugate that has selective and potent activity against tuberculosis and malaria. J Am Chem Soc 2011; 133:2076-9. [PMID: 21275374 PMCID: PMC3045749 DOI: 10.1021/ja109665t] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Although the antimalarial agent artemisinin itself is not active against tuberculosis, conjugation to a mycobacterial-specific siderophore (microbial iron chelator) analogue induces significant and selective antituberculosis activity, including activity against multi- and extensively drug-resistant strains of Mycobacterium tuberculosis. The conjugate also retains potent antimalarial activity. Physicochemical and whole-cell studies indicated that ferric-to-ferrous reduction of the iron complex of the conjugate initiates the expected bactericidal Fenton-type radical chemistry on the artemisinin component. Thus, this "Trojan horse" approach demonstrates that new pathogen-selective therapeutic agents in which the iron component of the delivery vehicle also participates in triggering the antibiotic activity can be generated. The result is that one appropriate conjugate has potent and selective activity against two of the most deadly diseases in the world.
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Affiliation(s)
- Marvin J Miller
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States.
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37
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Samarakoon U, Regier A, Tan A, Desany BA, Collins B, Tan JC, Emrich SJ, Ferdig MT. High-throughput 454 resequencing for allele discovery and recombination mapping in Plasmodium falciparum. BMC Genomics 2011; 12:116. [PMID: 21324207 PMCID: PMC3055840 DOI: 10.1186/1471-2164-12-116] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 02/17/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Knowledge of the origins, distribution, and inheritance of variation in the malaria parasite (Plasmodium falciparum) genome is crucial for understanding its evolution; however the 81% (A+T) genome poses challenges to high-throughput sequencing technologies. We explore the viability of the Roche 454 Genome Sequencer FLX (GS FLX) high throughput sequencing technology for both whole genome sequencing and fine-resolution characterization of genetic exchange in malaria parasites. RESULTS We present a scheme to survey recombination in the haploid stage genomes of two sibling parasite clones, using whole genome pyrosequencing that includes a sliding window approach to predict recombination breakpoints. Whole genome shotgun (WGS) sequencing generated approximately 2 million reads, with an average read length of approximately 300 bp. De novo assembly using a combination of WGS and 3 kb paired end libraries resulted in contigs ≤ 34 kb. More than 8,000 of the 24,599 SNP markers identified between parents were genotyped in the progeny, resulting in a marker density of approximately 1 marker/3.3 kb and allowing for the detection of previously unrecognized crossovers (COs) and many non crossover (NCO) gene conversions throughout the genome. CONCLUSIONS By sequencing the 23 Mb genomes of two haploid progeny clones derived from a genetic cross at more than 30× coverage, we captured high resolution information on COs, NCOs and genetic variation within the progeny genomes. This study is the first to resequence progeny clones to examine fine structure of COs and NCOs in malaria parasites.
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Affiliation(s)
- Upeka Samarakoon
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556, USA
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Reilly Ayala HB, Wacker MA, Siwo G, Ferdig MT. Quantitative trait loci mapping reveals candidate pathways regulating cell cycle duration in Plasmodium falciparum. BMC Genomics 2010; 11:577. [PMID: 20955606 PMCID: PMC3091725 DOI: 10.1186/1471-2164-11-577] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Accepted: 10/18/2010] [Indexed: 11/24/2022] Open
Abstract
Background Elevated parasite biomass in the human red blood cells can lead to increased malaria morbidity. The genes and mechanisms regulating growth and development of Plasmodium falciparum through its erythrocytic cycle are not well understood. We previously showed that strains HB3 and Dd2 diverge in their proliferation rates, and here use quantitative trait loci mapping in 34 progeny from a cross between these parent clones along with integrative bioinformatics to identify genetic loci and candidate genes that control divergences in cell cycle duration. Results Genetic mapping of cell cycle duration revealed a four-locus genetic model, including a major genetic effect on chromosome 12, which accounts for 75% of the inherited phenotype variation. These QTL span 165 genes, the majority of which have no predicted function based on homology. We present a method to systematically prioritize candidate genes using the extensive sequence and transcriptional information available for the parent lines. Putative functions were assigned to the prioritized genes based on protein interaction networks and expression eQTL from our earlier study. DNA metabolism or antigenic variation functional categories were enriched among our prioritized candidate genes. Genes were then analyzed to determine if they interact with cyclins or other proteins known to be involved in the regulation of cell cycle. Conclusions We show that the divergent proliferation rate between a drug resistant and drug sensitive parent clone is under genetic regulation and is segregating as a complex trait in 34 progeny. We map a major locus along with additional secondary effects, and use the wealth of genome data to identify key candidate genes. Of particular interest are a nucleosome assembly protein (PFL0185c), a Zinc finger transcription factor (PFL0465c) both on chromosome 12 and a ribosomal protein L7Ae-related on chromosome 4 (PFD0960c).
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Patel JJ, Thacker D, Tan JC, Pleeter P, Checkley L, Gonzales JM, Deng B, Roepe PD, Cooper RA, Ferdig MT. Chloroquine susceptibility and reversibility in a Plasmodium falciparum genetic cross. Mol Microbiol 2010; 78:770-87. [PMID: 20807203 DOI: 10.1111/j.1365-2958.2010.07366.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Mutations in the Plasmodium falciparum chloroquine (CQ) resistance transporter (PfCRT) are major determinants of verapamil (VP)-reversible CQ resistance (CQR). In the presence of mutant PfCRT, additional genes contribute to the wide range of CQ susceptibilities observed. It is not known if these genes influence mechanisms of chemosensitization by CQR reversal agents. Using quantitative trait locus (QTL) mapping of progeny clones from the HB3 × Dd2 cross, we show that the P. falciparum multidrug resistance gene 1 (pfmdr1) interacts with the South-East Asia-derived mutant pfcrt haplotype to modulate CQR levels. A novel chromosome 7 locus is predicted to contribute with the pfcrt and pfmdr1 loci to influence CQR levels. Chemoreversal via a wide range of chemical structures operates through a direct pfcrt-based mechanism. Direct inhibition of parasite growth by these reversal agents is influenced by pfcrt mutations and additional loci. Direct labelling of purified recombinant PfMDR1 protein with a highly specific photoaffinity CQ analogue, and lack of competition for photolabelling by VP, supports our QTL predictions. We find no evidence that pfmdr1 copy number affects CQ response in the progeny; however, inheritance patterns indicate that an allele-specific interaction between pfmdr1 and pfcrt is part of the complex genetic background of CQR.
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Affiliation(s)
- Jigar J Patel
- The Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, 205 Galvin Life Sciences, Notre Dame, IN 46556, USA
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Abstract
Although maps of intracellular interactions are increasingly well characterized, little is known about large-scale maps of host-pathogen protein interactions. The investigation of host-pathogen interactions can reveal features of pathogenesis and provide a foundation for the development of drugs and disease prevention strategies. A compilation of experimentally verified interactions between HIV-1 and human proteins and a set of HIV-dependency factors (HDF) allowed insights into the topology and intricate interplay between viral and host proteins on a large scale. We found that targeted and HDF proteins appear predominantly in rich-clubs, groups of human proteins that are strongly intertwined among each other. These assemblies of proteins may serve as an infection gateway, allowing the virus to take control of the human host by reaching protein pathways and diversified cellular functions in a pronounced and focused way. Particular transcription factors and protein kinases facilitate indirect interactions between HDFs and viral proteins. Discerning the entanglement of directly targeted and indirectly interacting proteins may uncover molecular and functional sites that can provide novel perspectives on the progression of HIV infection and highlight new avenues to fight this virus.
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Affiliation(s)
- Stefan Wuchty
- National Center of Biotechnology Information, National Institutes of Health, Bethesda, Maryland, USA.
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Tan JC, Tan A, Checkley L, Honsa CM, Ferdig MT. Variable numbers of tandem repeats in Plasmodium falciparum genes. J Mol Evol 2010; 71:268-78. [PMID: 20730584 DOI: 10.1007/s00239-010-9381-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Accepted: 08/09/2010] [Indexed: 11/29/2022]
Abstract
Genome variation studies in Plasmodium falciparum have focused on SNPs and, more recently, large-scale copy number polymorphisms and ectopic rearrangements. Here, we examine another source of variation: variable number tandem repeats (VNTRs). Interspersed low complexity features, including the well-studied P. falciparum microsatellite sequences, are commonly classified as VNTRs; however, this study is focused on longer coding VNTR polymorphisms, a small class of copy number variations. Selection against frameshift mutation is a main constraint on tandem repeats (TRs) in coding regions, while limited propagation of TRs longer than 975 nt total length is a minor restriction in coding regions. Comparative analysis of three P. falciparum genomes reveals that more than 9% of all P. falciparum ORFs harbor VNTRs, much more than has been reported for any other species. Moreover, genotyping of VNTR loci in a drug-selected line, progeny of a genetic cross, and 334 field isolates demonstrates broad variability in these sequences. Functional enrichment analysis of ORFs harboring VNTRs identifies stress and DNA damage responses along with chromatin modification activities, suggesting an influence on genome mutability and functional variation. Analysis of the repeat units and their flanking regions in both P. falciparum and Plasmodium reichenowi sequences implicates a replication slippage mechanism in the generation of TRs from an initially unrepeated sequence. VNTRs can contribute to rapid adaptation by localized sequence duplication. They also can confound SNP-typing microarrays or mapping short-sequence reads and therefore must be accounted for in such analyses.
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Affiliation(s)
- John C Tan
- The Eck Institute for Global Health, University of Notre Dame, 100 Galvin Life Sciences, Notre Dame, IN, 46556, USA.
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Wuchty S, Adams JH, Ferdig MT. A comprehensive Plasmodium falciparum protein interaction map reveals a distinct architecture of a core interactome. Proteomics 2009; 9:1841-9. [PMID: 19333996 DOI: 10.1002/pmic.200800383] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We derive a map of protein interactions in the parasite Plasmodium falciparum from conserved interactions in Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, and Escherichia coli and pool them with experimental interaction data. The application of a clique-percolation algorithm allows us to find overlapping clusters, strongly correlated with yeast specific conserved protein complexes. Such clusters contain core activities that govern gene expression, largely dominated by components of protein production and degradation processes as well as RNA metabolism. A critical role of protein hubs in the interactome of P. falciparum is supported by their appearance in multiple clusters and the tendencies of their interactions to reach into many distinct protein clusters. Parasite proteins with a human ortholog tend to appear in single complexes. Annotating each protein with the stage where it is maximally expressed we observe a high level of cluster integrity in the ring stage. While we find no signal in the trophozoite phase, expression patterns are reversed in the schizont phase, implying a preponderance of parasite specific functions in this late, invasive schizont stage. As such, the inference of potential protein interactions and their analysis contributes to our understanding of the parasite, indicating basic pathways and processes as unique targets for therapeutic intervention.
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Affiliation(s)
- Stefan Wuchty
- Northwestern Institute of Complexity, Northwestern University, Evanston, IL 60201, USA.
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Abstract
Motivation: Analysis of expression quantitative trait loci (eQTL) significantly contributes to the determination of gene regulation programs. However, the discovery and analysis of associations of gene expression levels and their underlying sequence polymorphisms continue to pose many challenges. Methods are limited in their ability to illuminate the full structure of the eQTL data. Most rely on an exhaustive, genome scale search that considers all possible locus–gene pairs and tests the linkage between each locus and gene. Result: To analyze eQTLs in a more comprehensive and efficient way, we developed the Graph based eQTL Decomposition method (GeD) that allows us to model genotype and expression data using an eQTL association graph. Through graph-based heuristics, GeD identifies dense subgraphs in the eQTL association graph. By identifying eQTL association cliques that expose the hidden structure of genotype and expression data, GeD effectively filters out most locus–gene pairs that are unlikely to have significant linkage. We apply GeD on eQTL data from Plasmodium falciparum, the human malaria parasite, and show that GeD reveals the structure of the relationship between all loci and all genes on a whole genome level. Furthermore, GeD allows us to uncover additional eQTLs with lower FDR, providing an important complement to traditional eQTL analysis methods. Contact:przytyck@ncbi.nlm.nih.gov
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Affiliation(s)
- Yang Huang
- National Center for Biotechnology Information, NLM, NIH, Bethesda, MD 20894, USA
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Anderson TJC, Patel J, Ferdig MT. Gene copy number and malaria biology. Trends Parasitol 2009; 25:336-43. [PMID: 19559648 DOI: 10.1016/j.pt.2009.04.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 03/26/2009] [Accepted: 04/03/2009] [Indexed: 12/16/2022]
Abstract
Alteration in gene copy number provides a simple way to change expression levels and alter phenotype. This was fully appreciated by bacteriologists more than 25 years ago, but the extent and implications of copy number polymorphism (CNP) have only recently become apparent in other organisms. New methods demonstrate the ubiquity of CNPs in eukaryotes and their medical importance in humans. CNP is also widespread in the Plasmodium falciparum genome and has an important and underappreciated role in determining phenotype. In this review, we summarize the distribution of CNP, its evolutionary dynamics within populations, its functional importance and its mode of evolution.
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Affiliation(s)
- Tim J C Anderson
- Southwest Foundation for Biomedical Research, San Antonio, TX 78245, USA.
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Roepe PD, Ferdig MT. P. falciparum Na(+)/H(+) exchanger (PfNHE) function and quinine resistance (QNR) [Reply to: Spillman et al. "Acid extrusion from the intraerythrocytic malaria parasite is not via a Na(+)/H(+) exchanger" Mol. Biochem. Parasitol. 2008 162 (1) 96-99]. Mol Biochem Parasitol 2009; 166:1-2; author reply 3. [PMID: 19428665 DOI: 10.1016/j.molbiopara.2009.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 12/22/2008] [Accepted: 01/13/2009] [Indexed: 10/20/2022]
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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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Affiliation(s)
- Louis J Nkrumah
- Department of Microbiology and Immunology, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461, USA
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Gonzales JM, Patel JJ, Ponmee N, Jiang L, Tan A, Maher SP, Wuchty S, Rathod PK, Ferdig MT. Regulatory hotspots in the malaria parasite genome dictate transcriptional variation. PLoS Biol 2008; 6:e238. [PMID: 18828674 PMCID: PMC2553844 DOI: 10.1371/journal.pbio.0060238] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Accepted: 08/18/2008] [Indexed: 11/19/2022] Open
Abstract
The determinants of transcriptional regulation in malaria parasites remain elusive. The presence of a well-characterized gene expression cascade shared by different Plasmodium falciparum strains could imply that transcriptional regulation and its natural variation do not contribute significantly to the evolution of parasite drug resistance. To clarify the role of transcriptional variation as a source of stain-specific diversity in the most deadly malaria species and to find genetic loci that dictate variations in gene expression, we examined genome-wide expression level polymorphisms (ELPs) in a genetic cross between phenotypically distinct parasite clones. Significant variation in gene expression is observed through direct co-hybridizations of RNA from different P. falciparum clones. Nearly 18% of genes were regulated by a significant expression quantitative trait locus. The genetic determinants of most of these ELPs resided in hotspots that are physically distant from their targets. The most prominent regulatory locus, influencing 269 transcripts, coincided with a Chromosome 5 amplification event carrying the drug resistance gene, pfmdr1, and 13 other genes. Drug selection pressure in the Dd2 parental clone lineage led not only to a copy number change in the pfmdr1 gene but also to an increased copy number of putative neighboring regulatory factors that, in turn, broadly influence the transcriptional network. Previously unrecognized transcriptional variation, controlled by polymorphic regulatory genes and possibly master regulators within large copy number variants, contributes to sweeping phenotypic evolution in drug-resistant malaria parasites. Development of the malaria parasite, Plasmodium falciparum, in the blood is driven by a number of different genes expressed at different times and at different levels. Exactly what influences such transcriptional changes remains elusive, particularly in regard to important phenotypes like drug resistance. Using cDNA microarray hybridizations from the progeny of a Plasmodium genetic cross, we mapped gene expression quantitative trait loci (eQTLs) in an experimental population of malaria parasites. Each gene's transcript level was used as a segregating phenotype to identify regions of the Plasmodium genome dictating transcriptional variation. Several regulatory hotspots controlled the majority of gene expression variation, mostly via trans-acting mechanisms. One, influencing the largest number of transcripts, coincided with an amplified region of the genome traditionally associated with multiple drug resistance (MDR). Overall, integration of two functional genomic tools (gene mapping and transcript quantitation) has revealed a system-wide rewiring of the parasite transcription network: pleiotropic phenotypic variation, driven by drug selection on genome structure that may be attributed in large part to adaptive copy number polymorphisms in the parasite. These structural variants alter the expression of genes within the amplicon as well as many genes scattered across the Plasmodium genome. Heritable levels of transcriptional variation, predominantly regulated by genomic copy number variants via trans mechanisms, are surprisingly abundant in drug-resistant malaria parasites.
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Affiliation(s)
- Joseph M Gonzales
- The Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Jigar J Patel
- The Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Napawan Ponmee
- Department of Chemistry and Global Health, University of Washington, Seattle, Washington, United States of America
| | - Lei Jiang
- Department of Chemistry and Global Health, University of Washington, Seattle, Washington, United States of America
| | - Asako Tan
- The Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Steven P Maher
- The Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Stefan Wuchty
- Northwestern Institute of Complexity, Northwestern University, Evanston, Illinois, United States of America
| | - Pradipsinh K Rathod
- Department of Chemistry and Global Health, University of Washington, Seattle, Washington, United States of America
| | - Michael T Ferdig
- The Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
- * To whom correspondence should be addressed. E-mail:
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Reilly HB, Wang H, Steuter JA, Marx AM, Ferdig MT. Quantitative dissection of clone-specific growth rates in cultured malaria parasites. Int J Parasitol 2007; 37:1599-607. [PMID: 17585919 PMCID: PMC2268714 DOI: 10.1016/j.ijpara.2007.05.003] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 05/08/2007] [Accepted: 05/10/2007] [Indexed: 11/16/2022]
Abstract
Measurement of parasite proliferation in cultured red blood cells underpins many facets of malaria research, from drug sensitivity assays to assessing the impact of experimentally altered genes on parasite growth, virulence and fitness. Pioneering efforts to grow Plasmodium falciparum in cultured red blood cells revolutionised malaria research and spurred the development of semi-high-throughput growth assays using radio-labelled hypoxanthine (Hx), an essential nucleic acid precursor, as a reporter of whole-cycle proliferation [Trager, W., Jensen, J.B., 1976. Human malaria parasites in continuous culture. Science 193, 673-675; Desjardins, R.E., Canfield, C.J., Haynes, J.D., Chulay, J.D., 1979. Quantitative assessment of antimalarial activity in vitro by a semiautomated microdilution technique. Antimicrob. Agents Chemother. 16, 710-718]. The isotopic Hx assay remains the standard quantitative growth assay with which newer non-radioactive procedures based on fluorescent DNA dyes or ELISA are compared. All of these readouts are surrogate reporters of changes in bulk parasitemias, reflecting proliferation over entire asexual reproductive cycles. While quantitatively robust and amenable to semi-high-throughput applications, these methods are blind to the underlying developmental and cellular events of growth in human red blood cells. Modern whole-genome tools including gene knockouts, mutagenesis and small molecule screens promise to reveal much about basic parasite biology; however methods to precisely quantify the within-cycle growth process are needed. Here we elaborate on the classical growth index, i.e. changes in parasitemia, by quantifying sub-phenotypes of a rapid proliferator, the multi-drug resistant clone Dd2, and a standard wild-type clone, HB3. These data illustrate differences in cycle duration, merozoite production, and invasion rate and efficiency that underpin Dd2's average 2-fold proliferation advantage over HB3 per erythrocytic cycle. The ability to refine growth phenotypes will inform the search for molecular determinants of differential parasite growth rates and broaden our understanding of killing mechanisms and cellular targets of antimalarial drugs.
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Affiliation(s)
| | | | | | | | - Michael T. Ferdig
- Corresponding author. Michael T. Ferdig, 280 Galvin Life Sciences; Notre Dame, IN 46556 USA. Tel.: +1 574 631 9973; fax: +1 574 631 0492. E-mail address:
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Cooper RA, Lane KD, Deng B, Mu J, Patel JJ, Wellems TE, Su X, Ferdig MT. Mutations in transmembrane domains 1, 4 and 9 of the Plasmodium falciparum chloroquine resistance transporter alter susceptibility to chloroquine, quinine and quinidine. Mol Microbiol 2007. [DOI: 10.1111/j.1365-2958.2007.05751.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
Recombinant progeny lines of Cryptosporidium parvum were generated by coinfecting immunosuppressed mice with two genetically distinct isolates of C. parvum. Progeny lines were obtained from a cross of parental lines MD x TU114 through targeted propagation in mice of progeny oocysts originating from populations lacking one parental allele at one or more loci. For each infection lineage this process was repeated until only a single allele remained for each marker, indicating that the progeny line was clonal. To study genetic recombination, 16 progeny clones were genotyped at 40 loci located on each of the eight chromosomes. The inheritance of parental alleles was significantly skewed towards the more virulent parent isolate MD. A contiguous 476 kb segment of chromosome V displayed MD allele in all progeny recovered, while MD and TU114 alleles were detected at other loci throughout the genome. The absence of alleles from one parental isolate in this chromosomal region may indicate phenotypic selection for the MD allele during the generation of these lines. A range for the meiotic crossover frequency was determined on the basis of 40 markers and the number of meioses estimated to have taken place during the crossing experiment. C. parvum exhibits a high rate of recombination commensurate with other Apicomplexa.
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Affiliation(s)
- Sultan Tanriverdi
- Tufts Cummings School of Veterinary Medicine, Division of Infectious Diseases, North Grafton, MA, USA
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