Project description:Transcription time course of Plasmodium falciparum parasite asexual blood stage progression in the presence of antimalarial drug CID5750730 (Compound C)
Project description:To combat the global burden of malaria, development of new drugs to replace or complement current therapies are urgently required. As drug resistance to existing treatments and clinical failures continue to rise, compounds targeting multiple life cycle stages and species need to be developed as a high priority. Here we show that the compound MMV1557817 is a nanomolar inhibitor of both Plasmodium falciparum and Plasmodium vivax aminopeptidases M1 and M17, leading to inhibition of end stage haemoglobin digestion in asexual parasites. Multi-stage analysis confirmed that MMV1557817 can also kill sexual stage P. falciparum, while cross-resistance studies confirmed the compound targets a mechanism of action distinct to current drug resistance mechanisms. Analysis of cross reactivity to homologous human enzymes shows the compound exhibits a high level of selectivity, whilst safety as well as druggability was confirmed in the murine model P. berghei. MMV1557817-resistant P. falciparum parasites displayed only low-level resistance (<3-fold) and exhibited a slow growth rate that was quickly outcompeted by wild type parasites. MMV1557817-resistant parasites digest significantly more haemoglobin and possess a mutation in PfA-M17 that induces partial destabilization of the PfA-M17 homohexamer, resulting in high-level resistance to specific PfA-M17 inhibition, but enhanced sensitivity to specific PfA-M1 inhibition, and importantly, these parasites were highly sensitive to artemisinin. Overall, these results confirm MMV1557817 as a potential lead compound for further drug development and highlight the potential of dual inhibition of M1 and M17 as an effective multi-species drug targeting strategy.
Project description:Malaria eradication requires the development of new drugs to combat drug-resistant parasites. The search for new chemical scaffolds that target novel pathways of the human malaria parasite Plasmodium falciparum is of highest priority. We identified bisbenzylisoquinoline alkaloids isolated from Cocculus sp. (trilobine derivatives) as active in the nanomolar range against P. falciparum blood stages. Synthesis of a library of 94 hemi-synthetic derivates allowed us to identify compound 84 (c-84) that kills multi-drug resistant clinical isolates in the nanomolar range (median IC50 ranging from 35-88nM). Efforts were made to obtain compounds with significantly improved preclinical properties. Out of those, compound 125 (c-125) delays the onset of parasitemia in P. berghei infected mice and inhibits P. falciparum transmission stages in vitro (culture assays) and in vivo using membrane feeding assay in the Anopheles stephensi vector. C-125 also impairs P. falciparum development in sporozoite-infected hepatocytes, in the low micromolar range. Finally, we used a chemical pull-down to identify potential protein targets of this chemical family. Our mass spectrometry analysis identified the parasite interactome with trilobine alkaloid, allowing us to identify protein partners belonging to metabolic pathways that have not been previously targeted by antimalarial drugs or implicated in drug-resistance mechanisms in malaria parasites.
Project description:Most malaria drug development focuses on parasite stages detected in red-blood cells even though to achieve eradication next-generation drugs active against both erythrocytic and exo-erythrocytic forms would be preferable. We applied a multifactorial approach to a set of >4,000 commercially available compounds with previously demonstrated blood stage activity (IC50 < 1 M-BM-5M), and identified chemical scaffolds with potent activity against both forms. From this screen, we identified an imidazolopiperazine scaffold series that was highly enriched among compounds active against Plasmodium liver stages. Our orally bioavailable lead imidazolopiperazine confers complete causal prophylactic protection (15 mg/kg) in rodent models of malaria and shows potent in vivo blood-stage therapeutic activity. The open source chemical tools resulting from our effort provide starting points for future drug discovery programs, as well as opportunities for researchers to investigate the biology of exo-erythrocytic forms. Genome DNA from IP resistant strains vs. Reference 3D7 or Dd2
Project description:Determination of gene expression level changes of whole genome during Plasmodium falciparum development in early liver stage (at 24h and 48h), compared to mixed blood stage and sporozoite stage. A set of Genes selected from this expression analysis are further verified by qPCR and a sub-set were tested for their vaccine efficacy.
Project description:Gene expression data from whole-blood collected from Kenyan children with Plasmodium falciparum malaria infection at acute hospital admission (n=15) and at convalescence (n=9). A clinical history design type is where the organisms clinical history of diagnosis, treatments, e.g. vaccinations, surgery etc. Disease State: with Plasmodium falciparum malaria infection at acute hospital admission and at convalescence
Project description:Healthy Kenyan children with (n=10) or without (n=14) a previous history of complicated Plasmodium falciparum infection had aliquots of their whole-blood cultured ex-vivo and either mock infected or infected with Plasmodium falciparum (A4 strain) for 5 (n=24) and 9 hours (n=11). A clinical history design type is where the organisms clinical history of diagnosis, treatments, e.g. vaccinations, surgery etc. Time: lenght of co-culture Infection: whole-blood cells cultured ex-vivo in the presence of either uninfected red blood cells or red blood cells infected with Plasmodium falciparum Disease State: Healthy individuals with (PrevHxMal) or without (NoHxMal) previous exposure to complicated Plasmodium falciparum infection
Project description:Gene expression data from Vietnamese subjects admitted to hospital with acute uncomplicated (n=6) or complicated (n=6) Plasmodium falciparum malaria infection had whole-blood samples collected at admission, 1 week later and 1 month later. Groups of assays that are related as part of a time series. Disease State: patient with complicated or uncomplicated Plasmodium falciparum malaria infection or Healthy control