Project description:The genomic DNAs of strains 263 of L. infantum and five derived independent resistant mutants to 5-fluorouracil were used in comparative genomic hybridizations to reveal the deletion and/or amplification events occured by drug resistance mechanisms. The human protozoan parasites Leishmania are prototrophic for pyrimidines and de novo pyrimidine biosynthesis is necessary for their growth. Five independent L. infantum mutants were selected for resistance to the pyrimidine analogue 5-fluorouracil (5-FU) in the hope to better understand the metabolism of pyrimidine in Leishmania. Analysis of the 5-FU mutants by comparative genomic hybridization and whole genome sequencing revealed amplification and deletion events as well as point mutations in metabolic genes involved in either the uridine salvage, folate or dTMP biosynthesis pathways. In particular, a dhfr-ts containing amplicon was observed in two mutants and a deletion of part of chromosome 10 was detected in one mutant. Point mutations in uridine phosphorybosyl transferase (UPRT), thymidine kinase (TK) and uridine phosphorylase (UP) were also discovered. Transfection experiments confirmed that these molecular alterations were responsible for the 5-FU resistance phenotype. Transport studies revealed that one resistant mutant was defective for uracil and 5-FU import although the identity of the transporter remains elusive. This study provided further insights in pyrimidine metabolism in Leishmania and confirmed that multiple mutations can co-exist in a cell to lead to resistance. Each independent resistant mutant to 5-fluorouracil was hybridizated with the wild-type L. infantum 263 to 10 microarrays, each with three biological replicates (independent cultures).
Project description:The genomic DNAs of strains 263 of L. infantum and five derived independent resistant mutants to 5-fluorouracil were used in comparative genomic hybridizations to reveal the deletion and/or amplification events occured by drug resistance mechanisms. The human protozoan parasites Leishmania are prototrophic for pyrimidines and de novo pyrimidine biosynthesis is necessary for their growth. Five independent L. infantum mutants were selected for resistance to the pyrimidine analogue 5-fluorouracil (5-FU) in the hope to better understand the metabolism of pyrimidine in Leishmania. Analysis of the 5-FU mutants by comparative genomic hybridization and whole genome sequencing revealed amplification and deletion events as well as point mutations in metabolic genes involved in either the uridine salvage, folate or dTMP biosynthesis pathways. In particular, a dhfr-ts containing amplicon was observed in two mutants and a deletion of part of chromosome 10 was detected in one mutant. Point mutations in uridine phosphorybosyl transferase (UPRT), thymidine kinase (TK) and uridine phosphorylase (UP) were also discovered. Transfection experiments confirmed that these molecular alterations were responsible for the 5-FU resistance phenotype. Transport studies revealed that one resistant mutant was defective for uracil and 5-FU import although the identity of the transporter remains elusive. This study provided further insights in pyrimidine metabolism in Leishmania and confirmed that multiple mutations can co-exist in a cell to lead to resistance.
Project description:We explored the potential reprogramming of Leishmania infantum proteome during its stationary phase after an initial, single-dose exposure to EVs released by drug-resistant parasites
Project description:Given the discontinuation of various first-line drugs for visceral leishmaniasis (VL), large-scale in vivo drug screening, establishment of a relapse model in rodents, immunophenotyping and transcriptomics were combined to study persistent infections and therapeutic failure. Double bioluminescent/fluorescent Leishmania infantum and L. donovani reporter lines enabled the identification of long-term hematopoietic stem cells (LT-HSC) as a niche with remarkably high parasite burdens, a feature confirmed for human hematopoietic stem cells (hHSPC). LT-HSC are more tolerant to antileishmanial drug action and serve as source of relapse. A unique transcriptional “StemLeish” signature in these cells was defined byupregulated TNF/NF-kB and RGS1/TGF-β/SMAD/SKIL signalling, and a downregulated oxidative burst.Cross-species analyses demonstrated significant overlap with human VL and HIV co-infected blood transcriptomes. In summary, the identification of LT-HSC as a drug- and oxidative stress-resistant niche,undergoing a conserved transcriptional reprogramming underlying Leishmania persistence and treatment failure, may open new therapeutic avenues for leishmaniasis.
Project description:To investigate dendritic cells-Leishmania interaction, the transcriptional profile of bone marrow-derived dendritic cells (BMDCs) infected with Leishmania infantum or of cells exposed to chemically inactivated parasites was assessed
Project description:This SuperSeries is composed of the following subset Series: GSE9947: Transcriptional analysis of Leishmania infantum methotrexate resistant strains using full-genome DNA microarrays GSE9948: Transcriptional analysis of Leishmania major methotrexate resistant strains using full-genome DNA microarrays Keywords: SuperSeries Refer to individual Series
Project description:To ascertain which genes are involved in the outcome of Leishmania infantum infection and immunopathology of human visceral leishmaniasis (VL), we investigated the transcriptional profile of whole blood samples from patients diagnosed with active VL compared to asymptomatic individuals (positive serology for Leishmania, but without clinical signs of disease) and healthy control samples.