Treatment of leishmaniasis: study of molecular basis involved in susceptibility and resistance to miltefosine and paromomycin in Leishmania spp.

Leishmaniases, a group of neglected and endemic diseases in almost 100 countries, are caused by protozoan parasites of the genus Leishmania and transmitted by infected sandflies. The main clinical forms are visceral leishmaniasis and cutaneous leishmaniasis, caused mainly by Leishmania infantum, and L. braziliensis and L. amazonensis in Brazil. The treatment of leishmaniasis is restricted to a restricted number of drugs that have limitations regarding cost, toxicity and variable efficacy rates. Recently, miltefosine was approved for the treatment of cutaneous leishmaniasis in Brazil, the only oral drug available for the treatment of this set of diseases. Reduction in cure rates in the treatment of leishmaniasis, due to the selection of resistant parasites and/or co-infection with the HIV virus, has become common in treatment. However, reports of resistance to these drugs are scarce and still little studied, particularly in Brazil. Paromomycin, an aminoglycoside, is used to treat visceral leishmaniasis, with cure rates higher than 90% in Southeast Asia, but not yet approved for the treatment of leishmaniasis in Brazil. In this project, we propose to investigate the molecular basis involved in the phenotype of susceptibility and resistance to miltefosine and paromomycin, through the characterization of clinical isolates and resistant strains of the main species responsible for leishmaniasis in Brazil, using large-scale genomic sequencing technology. The identified genes will be validated through genetic manipulation of the parasite, using reverse genetics tools, followed by phenotypic in vitro and in vivo drug susceptibility tests. This study will elucidate the molecular basis involved in susceptibility and resistance to miltefosine and paromomycin, in addition to investigating the clinical relevance of resistant strains selected in vitro.