Project description:Drug resistance is a major public health challenge in Leishmaniasis chemotherapy, particularly in the case of emerging Leishmania/HIV-1 co-infections. Recently, we have delineated the mechanism of cell death induced by the HIV-1 protease inhibitor, Nelfinavir, in the Leishmania parasite. In order to investigate the underlying molecular mechanism involved in Nelfinavir resistance, in vitro Nelfinavir resistant amastigotes were developed by direct drug pressure in culture. RNA expression profiling analyses of closely related Leishmania species were used as a screening tool to compare Nelfinavir-resistant and -sensitive parasites in order to identify candidate genes involved in drug resistance, and several genes were found to be differentially expressed. Comparative gene hybridization (CGH) analyses of Nelfinavir-resistant and -sensitive Leishmania using whole-genome 60-mer oligonucleotide microarrays were also carried out. RNA expression profiles and the CGH of Nelfinavir resistant vs sensitive Leishmania amastigotes suggest that parasites regulate mRNA levels either by modulating gene copy numbers through chromosome aneuploidy, or gene deletion/duplication by homologous recombination. Interestingly, supernumerary chromosomes 6 and 11 in the resistant parasites lead to upregulation of the ABC class of transporters, which are involved in vesicular trafficking. Transporter assays using radiolabeled Nelfinavir suggest that the drug accumulates in greater amounts in the resistant parasites and in a time dependent manner. Furthermore, high-resolution electron microscopy showed an increased number of vacuoles in Nelfinavir-resistant parasites. Together these results suggest that Nelfinavir is rapidly and dramatically sequestered in these intracellular vesicles.
Project description:Drug resistance is a major public health challenge in Leishmaniasis chemotherapy, particularly in the case of emerging Leishmania/HIV-1 co-infections. Recently, we have delineated the mechanism of cell death induced by the HIV-1 protease inhibitor, Nelfinavir, in the Leishmania parasite. In order to investigate the underlying molecular mechanism involved in Nelfinavir resistance, in vitro Nelfinavir resistant amastigotes were developed by direct drug pressure in culture. RNA expression profiling analyses of closely related Leishmania species were used as a screening tool to compare Nelfinavir-resistant and -sensitive parasites in order to identify candidate genes involved in drug resistance, and several genes were found to be differentially expressed. Comparative gene hybridization (CGH) analyses of Nelfinavir-resistant and -sensitive Leishmania using whole-genome 60-mer oligonucleotide microarrays were also carried out. RNA expression profiles and the CGH of Nelfinavir resistant vs sensitive Leishmania amastigotes suggest that parasites regulate mRNA levels either by modulating gene copy numbers through chromosome aneuploidy, or gene deletion/duplication by homologous recombination. Interestingly, supernumerary chromosomes 6 and 11 in the resistant parasites lead to upregulation of the ABC class of transporters, which are involved in vesicular trafficking. Transporter assays using radiolabeled Nelfinavir suggest that the drug accumulates in greater amounts in the resistant parasites and in a time dependent manner. Furthermore, high-resolution electron microscopy showed an increased number of vacuoles in Nelfinavir-resistant parasites. Together these results suggest that Nelfinavir is rapidly and dramatically sequestered in these intracellular vesicles.
Project description:Drug resistance is a major public health challenge in Leishmaniasis chemotherapy, particularly in the case of emerging Leishmania/HIV-1 co-infections. Recently, we have delineated the mechanism of cell death induced by the HIV-1 protease inhibitor, Nelfinavir, in the Leishmania parasite. In order to investigate the underlying molecular mechanism involved in Nelfinavir resistance, in vitro Nelfinavir resistant amastigotes were developed by direct drug pressure in culture. RNA expression profiling analyses of closely related Leishmania species were used as a screening tool to compare Nelfinavir-resistant and -sensitive parasites in order to identify candidate genes involved in drug resistance, and several genes were found to be differentially expressed. Comparative gene hybridization (CGH) analyses of Nelfinavir-resistant and -sensitive Leishmania using whole-genome 60-mer oligonucleotide microarrays were also carried out. RNA expression profiles and the CGH of Nelfinavir resistant vs sensitive Leishmania amastigotes suggest that parasites regulate mRNA levels either by modulating gene copy numbers through chromosome aneuploidy, or gene deletion/duplication by homologous recombination. Interestingly, supernumerary chromosomes 6 and 11 in the resistant parasites lead to upregulation of the ABC class of transporters, which are involved in vesicular trafficking. Transporter assays using radiolabeled Nelfinavir suggest that the drug accumulates in greater amounts in the resistant parasites and in a time dependent manner. Furthermore, high-resolution electron microscopy showed an increased number of vacuoles in Nelfinavir-resistant parasites. Together these results suggest that Nelfinavir is rapidly and dramatically sequestered in these intracellular vesicles. Two condition experiment: NFV-sensitive vs resistant. Biological replicates: Three. One dye swap.
Project description:Drug resistance is a major public health challenge in Leishmaniasis chemotherapy, particularly in the case of emerging Leishmania/HIV-1 co-infections. Recently, we have delineated the mechanism of cell death induced by the HIV-1 protease inhibitor, Nelfinavir, in the Leishmania parasite. In order to investigate the underlying molecular mechanism involved in Nelfinavir resistance, in vitro Nelfinavir resistant amastigotes were developed by direct drug pressure in culture. RNA expression profiling analyses of closely related Leishmania species were used as a screening tool to compare Nelfinavir-resistant and -sensitive parasites in order to identify candidate genes involved in drug resistance, and several genes were found to be differentially expressed. Comparative gene hybridization (CGH) analyses of Nelfinavir-resistant and -sensitive Leishmania using whole-genome 60-mer oligonucleotide microarrays were also carried out. RNA expression profiles and the CGH of Nelfinavir resistant vs sensitive Leishmania amastigotes suggest that parasites regulate mRNA levels either by modulating gene copy numbers through chromosome aneuploidy, or gene deletion/duplication by homologous recombination. Interestingly, supernumerary chromosomes 6 and 11 in the resistant parasites lead to upregulation of the ABC class of transporters, which are involved in vesicular trafficking. Transporter assays using radiolabeled Nelfinavir suggest that the drug accumulates in greater amounts in the resistant parasites and in a time dependent manner. Furthermore, high-resolution electron microscopy showed an increased number of vacuoles in Nelfinavir-resistant parasites. Together these results suggest that Nelfinavir is rapidly and dramatically sequestered in these intracellular vesicles. Two condition experiment: NFV-sensitive vs resistant. Biological replicates: Three. One dye swap.
Project description:A transport system for pentamidine in Leishmania donovani and Leishmania amazonensis promastigotes and axenic amastigotes has been identified and characterized. Pentamidine is not metabolized by these parasites. Its uptake process is saturable, carrier-mediated and energy-dependent. This drug does not inhibit purine or pyrimidine uptake, whereas it inhibits uptake of several amino acids non-competitively and that of putrescine and spermidine competitively. The results suggest that pentamidine shares polyamine-carrier systems in these parasites.
Project description:Gene expression analysis was carried out between experimental miltefosine resistant L.donovani (adapted to 30ug/ml miltefosine drug pressure) and its corresponding wild type miltefosine senstive parasite
Project description:The mRNA expression of antimony resistant strains of Leishmania donovani was compared to the expression of the sensitive Leishmania donovani.
Project description:Kinetoplast maxicircle DNA sequence organisation was investigated in Leishmania donovani, strain 1S LdBob. Gene arrangement in the coding (conserved) region of the maxicircle is collinear with that of most trypanosomatids, with individual genes showing 80-90% nucleotide identity to Leishmania tarentolae, strain UC. The notable exception was an integration of a full-size minicircle sequence in the ND1 gene coding region found in L. donovani. Editing patterns of the mitochondrial mRNAs investigated also followed L. tarentolae UC patterns, including productive editing of the components of respiratory complexes III-V, and ribosomal protein S12 (RPS12), as well as the lack of productive editing in five out of six pan-edited cryptogenes (ND3, ND8, ND9, G3, G4) found in these species. Several guide RNAs for the editing events were localised in minicircles and maxicircles in the locations that are conserved between the species. Mitochondrial activity, including rates of oxygen consumption, the presence and the levels of respiratory complexes and their individual subunits and the steady-state levels of several mitochondrial-encoded mRNAs were essentially the same in axenically grown amastigotes and in promastigotes of L. donovani. However, some modulation of mitochondrial activity between these developmental stages was suggested by the finding of an amastigote-specific component in complex IV, a down-regulation of mitochondrial RNA-binding proteins (MRP) and MRP-associated protein (MRP-AP) in amastigotes, and by variations in the levels of RPS12, ND3, ND9, G3 and G4 pre-edited transcripts.