Functional analysis of iron superoxide dismutase-A in wild-type and antimony-resistant Leishmania braziliensis and Leishmania infantum lines

• SOD activity in SbIII-resistant Lb and Li lines is higher than their wild-type lines.
• LbWTS and LiWTS clonal lines overexpressing FeSOD-A are more resistant to SbIII.
• LbSbR and LiSbR lines overexpressing FeSOD-A did not alter the resistance to SbIII.
• LbWTS line overexpressing FeSOD-A is more tolerant to paraquat.
• FeSOD-A may be involved in SbIII-resistance phenotype in L. braziliensis and L. infantum.

In this work, we characterized the gene encoding iron superoxide dismutase-A (FeSOD-A) in wild-type (WTS) and antimony-resistant (SbR) L. (Viannia) braziliensis and L. (Leishmania) infantum lines, which were selected in vitro. FeSOD-A transcript and protein expression were similar in all tested lines; however, specific enzyme activity analysis revealed higher superoxide dismutase activity in SbIII-resistant LbSbR and LiSbR lines than in the corresponding WTS lines. These parasites were also more tolerant to oxidative stress generated by the herbicide paraquat. Functional analysis showed that in comparison to non-transfected lines, wild-type LbWTS and LiWTS clones overexpressing the FeSOD-A enzyme are 1.6- and 1.7-fold more resistant to SbIII, respectively. Our results suggest that FeSOD-A is involved in the antimony resistance phenotype in L. (V.) braziliensis and L. (L.) infantum.

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