Visceral leishmaniasis: genomics approaches for integrated molecular analysis of host and parasite

Abstract

Visceral leishmaniasis (VL) in Brazil is caused by protozoan parasites Leishmania infantum. It is a chronic and disseminated disease that can be potentially fatal if untreated. Interestingly, most people infected are asymptomatic, whereas approximately 15% of L. infantum infections develop clinical manifestations, which range from mild to severe forms of disease. Both host immune responses and the genetics of parasites are crucial to the outcome of infection; however the molecular mechanisms involved in the pathogenesis of VL remain poorly understood. We believe that molecular analyses of leukocytes from asymptomatic individuals (resistants to VL), diseased and cured patients, as well as the genomic analyses of clinical isolates will provide insightful information to elucidate the molecular mechanisms of parasite/host interaction that underlie the outcome of infection. Thus, the aim of this proposal is performing an integrated molecular analysis of VL through the Functional Genomics of host (whole blood RNA-seq) and the Comparative Genomics of parasites (WGS, whole-genome sequencing) for data integration that can be helpful to discovery of novel targets for therapies and drugs. Our preliminary results on RNA-seq analyses of blood leukocytes from VL patients and WGS of Leishmania clinical isolates reveal that this is an innovative and promising research proposal. Through the RNA-seq analyses of symptomatic infected patients before (diseased patients) and after (cured patients) of being submitted to the conventional treatment, asymptomatic patients and healthy control individuals, the gene signatures related to VL will be identified. The dual RNA-seq of patient samples will identify Leishmania transcripts. Also, a protocol for RNA-seq of whole blood stimulation will be developed. Comparative Genomics analyses of clinical isolates will determine ploidy, chromosome somy, copy number variations (CNVs) and single-nucleotide polymorphisms (SNPs) and genes or genomic regions associated to resistance to conventional drugs, beyond the valuable biological information about Brazilian strains of parasites. Finally, according to the purpose of FAPESP Young Investigator Award, this proposal aims to establish a novel research area (Genomics of host/parasite interaction in leishmaniasis) at the Department of Genetics and Evolution of the Federal University of São Carlos. (AU)