[Differential expression of proteins in Leishmania (Viannia) panamensis associated with mechanisms of resistance to meglumine antimoniate].

INTRODUCTION: The well-known drug resistance mechanisms to pentavalent antimony have been widely described in strains of the Leishmania subgenus, but little is known about the mechanisms of resistance and the proteins associated with it in strains of the Viannia subgenus such as Leishmania panamensis.

OBJECTIVE: Differentially expressed proteins were identified between pentavalent antimonial sensitive and resistant L. panamensis (UA140) strains, and the role of these proteins was analyzed as possible resistance mechanisms.

MATERIALS AND METHODS: The protein lysates of pentavalent antimony sensitive and resistant strains were separated by two-dimensional gel electrophoresis,and the protein patterns compared. The proteins identified as overexpressed were separated and analyzed using MALDI-TOF/TOF (Matrix Assisted Laser Desorption Ionization/Time of Flight). The level of mRNA expression of five of these proteins was quantified using real-time PCR.

RESULTS: On the 2-dimensional gels, 532 ± 39 protein spots were identified for the sensitive strains, and 541 ± 43 spots for the resistant strains. Ten spots were overexpressed in the resistant strain and identified as heat shock protein (Hsp60 mitochondrial, Hsp70 cytosolic and mitochondrial), disulfide isomerase, cysteine protease, enolase, elongation factor 5-alpha, the proteasome alpha-5 subunit and two hypothetical proteins named as Sp(2) and Sp(25).

CONCLUSION: This is the first proteomic study conducted with a L. panamensis resistant strain where several proteins were identified and related with the parasite resistance mechanism to pentavalent antimony. This opens the way for future studies aimed at modulating the drug resistance or at evaluating these proteins as therapeutic targets.