Identificação de proteínas diferencialmente expressas em Leishmania amazonensis relacionadas com a diminuição da infecciosidade dos parasitas

Abstract

Leishmaniasis is an endemic disease that affects people in five continents and 98 countries, including Brazil, being officially reported 58,000 new cases of visceral leishmaniasis and 220,000 new cases of cutaneous leishmaniasis each year. Leishmania amazonensis , a causative agent of leishmaniasis, can cause a wide variety of clinical manifestations of the disease. The aim of this study was to analyzethe relationship between the L. amazonensis axenic cultivation for long periods with the infectivity ability of the parasite in order to identify proteins that may be involved in this process. For that purpose, L. amazonensis stationary phase was grown for 150 days and aliquots were collected every 50 days, been used to analysis of of infectivity of the parasite by in vitro and in vivo experiments, and to proceed with proteomic characterization. After 2-DE, from the 315 spots with variation in intensity throughout the cultivation, 258 were identified by mass spectrometry. From the 56 selected proteins, 37 have possible decreased of expression over the passages and 19 different proteins showed possible increased of expression during the parasite cultivation. The expression variation of five of these proteins was validated by Immunoblotting. Twodimensional electrophoresis associated with mass spectrometry and bioinformatics analyzes showed that loss of infectivity observed in cultured parasites for prolonged periods under axenic conditions may be caused by the control of specific metabolic pathways, as well as by the control of the performance of the proteins involved with the parasite redox system or by changes in cytoskeletal proteins. The information presented in this study may help to a better understanding of biological processes involved in the reduction of infectivity of L. amazonensis when subjected to axenic cultures for long periods of time. Moreover, these findings may represent a contribution to the elucidation of novel vaccine candidates, diagnostic agents and / or immunotherapeutic targets against the parasite-induced disease, using known and hypothetical proteins with significant changes in their expression along the axenic cultures.