Project description:Artemisinin resistance in Plasmodium falciparum malaria has emerged in western Cambodia. This is a major threat to global plans to control and eliminate malaria as the artemisinins are a key component of antimalarial treatment throughout the world. Using DNA microarrays we identify key features of a transcriptional profile that are associated with the delayed parasite clearance phenotype. These include reduced expression of several basic metabolic and cellular pathways in the early stages, and increased expression of essentially all functionalities associated with protein metabolism in the later stages of P. falciparum intraerythrocytic development. This is consistent with the reduced ring stage susceptibility that characterizes artemisinin resistant P. falciparum. This modulation of the P. falciparum intraerythrocytic transcriptome may result from differential expression of several regulatory proteins such as transcription factors of chromatin remodeling associated factors. In addition, the artemisinin resistant phenotype is strongly associated with a specific pattern of copy number variations, some of which are linked with differential expression of several regulatory proteins such as histone 4 and zinc permease. This study reports the first global transcriptional survey of artemisinin resistant parasites and provides a set of candidate genes for further investigation. 11 P. falciparum parasites (field isolates) which are either Artemsinin resistant or sensitive from 3 study sites (Pailin in Cambodia, Xepon in Laos, Mae Sot in Thailand) were sampled, grown ex-vivo over 48 hours and harvested at regular intervals. RNA from a total of 91 samples were extracted. Synthesis of target DNA was carried out as previously described: Mackinnon, M.J. et al. Comparative transcriptional and genomic analysis of Plasmodium falciparum field isolates. PLoS Pathog 5, e1000644 (2009), and used in microarray hybridizations.
Project description:Artemisinin resistance in Plasmodium falciparum malaria has emerged in western Cambodia. This is a major threat to global plans to control and eliminate malaria as the artemisinins are a key component of antimalarial treatment throughout the world. Using DNA microarrays we identify key features of a transcriptional profile that are associated with the delayed parasite clearance phenotype. These include reduced expression of several basic metabolic and cellular pathways in the early stages, and increased expression of essentially all functionalities associated with protein metabolism in the later stages of P. falciparum intraerythrocytic development. This is consistent with the reduced ring stage susceptibility that characterizes artemisinin resistant P. falciparum. This modulation of the P. falciparum intraerythrocytic transcriptome may result from differential expression of several regulatory proteins such as transcription factors of chromatin remodeling associated factors. In addition, the artemisinin resistant phenotype is strongly associated with a specific pattern of copy number variations, some of which are linked with differential expression of several regulatory proteins such as histone 4 and zinc permease. This study reports the first global transcriptional survey of artemisinin resistant parasites and provides a set of candidate genes for further investigation. 6 P. falciparum parasites (field isolates) which are either Artemsinin resistant or sensitive from 3 study sites (Pailin in Cambodia, Xepon in Laos, Mae Sot in Thailand) were sampled and harvested for genomic DNA. gDNA from a total of 6 samples were extracted by phenol chloroform. Synthesis of labelled target DNA was carried out as previously described: Mackinnon, M.J. et al. Comparative transcriptional and genomic analysis of Plasmodium falciparum field isolates. PLoS Pathog 5, e1000644 (2009), and used in comparative genomic microarray hybridizations (CGH).
Project description:The objective of our study is to characterize gene expression signatures associated with in vivo artemisinin-resistance phenotype in this large-scale genome-wide association study. To achieve this goal, we employed microarray technology to establish the global gene expression profiles of isolates sampled from 1043 patients, of whom after treatment with ACTs (artemisinin combination therapy) displayed differential rates of parasite clearance. P. falciparum isolates were sampled from the whole blood of 1043 malaria-infected patients prior to ACT treatment. Sampling was done across 14 field sites spanning across South East Asia (Pailin, Pursat, Preah Vihear, Rattanakiri in Cambodia; Mae Sot, Srisakhet, Khun Han, Ranong in Thailand; Shwe Kyin in Myanmar; Binh Phuoc in Vietnam; Attapeu in Laos), to Bangladesh and African DR Congo from 2010 to 2012. RNA were extracted and synthesis and amplification of target DNA was carried out as described in Bozdech, Z., S. Mok & A. P. Gupta, (2013) DNA microarray-based genome-wide analyses of Plasmodium parasites. Methods in molecular biology 923: 189-211 (PMID 22990779), to generate sufficient material for hybridizations against a common RNA reference pool of 3D7 strain using a microarray platform.