Dataset Information

Assessing the cost-benefit effect of a Plasmodium falciparum drug resistance mutation on parasite growth in vitro.

ABSTRACT: Plasmodium falciparum mutations associated with antimalarial resistance may be beneficial for parasites under drug pressure, although they may also cause a fitness cost. We herein present an in vitro model showing how this combined effect on parasite growth varies with the drug concentration and suggest a calculated drug-specific cost-benefit index, indicating the possible advantage for mutated parasites. We specifically studied the D-to-Y change at position 1246 encoded by the pfmdr1 gene (pfmdr1 D1246Y) in relation to amodiaquine resistance. Susceptibilities to amodiaquine, desethylamodiaquine, and chloroquine, as well as relative fitness, were determined for two modified isogenic P. falciparum clones differing only in the pfmdr1 1246 position. Data were used to create a new comparative graph of relative growth in relation to the drug concentration and to calculate the ratio between the benefit of resistance and the fitness cost. Results were related to an in vivo allele selection analysis after amodiaquine or artesunate-amodiaquine treatment. pfmdr1 1246Y was associated with decreased susceptibility to amodiaquine and desethylamodiaquine but at a growth fitness cost of 11%. Mutated parasites grew less in low drug concentrations due to a predominating fitness cost, but beyond a breakpoint concentration they grew more due to a predominating benefit of increased resistance. The cost-benefit indexes indicated that pfmdr1 1246Y was most advantageous for amodiaquine-exposed parasites. In vivo, a first drug selection of mutant parasites followed by a fitness selection of wild-type parasites supported the in vitro data. This cost-benefit model may predict the risk for selection of drug resistance mutations in different malaria transmission settings.

SUBMITTER: Froberg G

PROVIDER: S-EPMC3553735 | biostudies-literature | 2013 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Assessing the cost-benefit effect of a Plasmodium falciparum drug resistance mutation on parasite growth in vitro.

Fröberg Gabrielle G Ferreira Pedro Eduardo PE Mårtensson Andreas A Ali Abdullah A Björkman Anders A Gil José Pedro JP

Antimicrobial agents and chemotherapy 20121203 2

Plasmodium falciparum mutations associated with antimalarial resistance may be beneficial for parasites under drug pressure, although they may also cause a fitness cost. We herein present an in vitro model showing how this combined effect on parasite growth varies with the drug concentration and suggest a calculated drug-specific cost-benefit index, indicating the possible advantage for mutated parasites. We specifically studied the D-to-Y change at position 1246 encoded by the pfmdr1 gene (pfmd ...[more]

PMID: 23208719

Similar Datasets

Project description:BackgroundThe screening of lead compounds against in vitro parasite cultures is an essential step in the development of novel anti-malarial drugs, but currently relies on laboratory parasite lines established in vitro during the last century. This study sought to establish in continuous culture a series of recent Plasmodium falciparum isolates to represent the current parasite populations in Africa, all of which are now exposed to artemisinin combination therapy.MethodsPre-treatment P. falciparum isolates were obtained in EDTA, and placed into continuous culture after sampling of DNA. One post-treatment blood sample was also collected for each donor to monitor parasite clonality during clearance in vivo. IC?? estimates were obtained for 11 anti-malarial compounds for each established parasite line, clonal multiplicity measured in vivo and in vitro, and polymorphic sites implicated in parasite sensitivity to drugs were investigated at the pfmdr1, pfcrt, pfdhfr, pfdhps and pfap2mu loci before and after treatment, and in the cultured lines.ResultsPlasmodium falciparum isolates from seven malaria patients with recent travel to three West African and two East African countries were successfully established in long-term culture. One of these, HL1211, was from a patient with recrudescent parasitaemia 14 days after a full course of artemether-lumefantrine. All established culture lines were shown to be polyclonal, reflecting the in vivo isolates from which they were derived, and at least two lines reliably produce gametocytes in vitro. Two lines displayed high chloroquine IC?? estimates, and carried the CVIET haplotype at codons 72-76, whereas the remaining five lines carried the CVMNK haplotype and were sensitive in vitro. All were sensitive to the endoperoxides dihydroartemisinin and OZ277, but IC?? estimates for lumefantrine varied, with the least sensitive parasites carrying pfmdr1 alleles encoding Asn at codon 86.ConclusionsThis study describes the establishment in continuous culture, in vitro drug sensitivity testing and molecular characterization of a series of multiclonal P. falciparum isolates taken directly from UK malaria patients following recent travel to various malaria-endemic countries in Africa. These "HL" isolates are available as an open resource for studies of drug response, antigenic diversity and other aspects of parasite biology.

Project description:The emergence and spread in Southeast Asia of Plasmodium falciparum resistance to artemisinin (ART) derivatives, the cornerstone of first-line artemisinin-based combination therapies (ACTs), underscore the urgent need to identify suitable replacement drugs. Discovery and development efforts have identified a series of ozonides with attractive chemical and pharmacological properties that are being touted as suitable replacements. Partial resistance to ART, defined as delayed parasite clearance in malaria patients treated with an ART derivative or an ACT, has been associated with mutations in the P. falciparum K13 gene. In light of reports showing that ART derivatives and ozonides share similar modes of action, we have investigated whether parasites expressing mutant K13 are cross-resistant to the ozonides OZ439 (artefenomel) and OZ227 (arterolane). This work used a panel of culture-adapted clinical isolates from Cambodia that were genetically edited to express variant forms of K13. Phenotypic analyses employed ring-stage survival assays (ring-stage survival assay from 0 to 3 h [RSA0-3h]), whose results have earlier been shown to correlate with parasite clearance rates in patients. Our results document cross-resistance between OZ277 and dihydroartemisinin (DHA), a semisynthetic derivative of ART, in parasites carrying the K13 mutations C580Y, R539T, and I543T. For OZ439, we observed cross-resistance only for parasites that carried the rare K13 I543T mutation, with no evidence of cross-resistance afforded by the prevalent C580Y mutation. Mixed-culture competition experiments with isogenic lines carrying modified K13 revealed variable growth deficits depending on the K13 mutation and parasite strain and provide a rationale for the broad dissemination of the fitness-neutral K13 C580Y mutation throughout strains currently circulating in Southeast Asia.IMPORTANCE ACTs have helped halve the malaria disease burden in recent years; however, emerging resistance to ART derivatives threatens to reverse this substantial progress. Resistance is driven primarily by mutations in the P. falciparum K13 gene. These mutations pose a threat to ozonides, touted as promising alternatives to ARTs that share a similar mode of action. We report that DHA was considerably more potent than OZ439 and OZ277 against ART-sensitive asexual blood-stage parasites cultured in vitro We also document that mutant K13 significantly compromised the activity of the registered drug OZ277. In contrast, OZ439 remained effective against most parasite lines expressing mutant K13, with the exception of I543T that merits further monitoring in field-based OZ439 efficacy studies. K13 mutations differed considerably in their impact on parasite growth rates, in a strain-dependent context, with the most prevalent C580Y mutation being fitness neutral in recently culture-adapted strains from Cambodia, the epicenter of emerging ART resistance.

Dataset Information

Assessing the cost-benefit effect of a Plasmodium falciparum drug resistance mutation on parasite growth in vitro.

Publications

Assessing the cost-benefit effect of a Plasmodium falciparum drug resistance mutation on parasite growth in vitro.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets