title: Molecular characterization and functional analysis of pteridine reductase in wild-type and antimony-resistant Leishmania lines.
abstract: Pteridine reductase (PTR1) is an NADPH-dependent reductase that participates in the salvage of pteridines, which are essential to maintain growth of Leishmania. In this study, we performed the molecular characterization of ptr1 gene in wild-type (WTS) and SbIII-resistant (SbR) lines from Leishmania guyanensis (Lg), Leishmania amazonensis (La), Leishmania braziliensis (Lb) and Leishmania infantum (Li), evaluating the chromosomal location, mRNA levels of the ptr1 gene and PTR1 protein expression. PFGE results showed that the ptr1 gene is located in a 797 kb chromosomal band in all Leishmania lines analyzed. Interestingly, an additional chromosomal band of 1070 kb was observed only in LbSbR line. Northern blot results showed that the levels of ptr1 mRNA are increased in the LgSbR, LaSbR and LbSbR lines. Western blot assays using the polyclonal anti-LmPTR1 antibody demonstrated that PTR1 protein is more expressed in the LgSbR, LaSbR and LbSbR lines compared to their respective WTS counterparts. Nevertheless, no difference in the level of mRNA and protein was observed between the LiWTS and LiSbR lines. Functional analysis of PTR1 enzyme was performed to determine whether the overexpression of ptr1 gene in the WTS L. braziliensis and L. infantum lines would change the SbIII-resistance phenotype of transfected parasites. Western blot results showed that the expression level of PTR1 protein was increased in the transfected parasites compared to the non-transfected ones. IC50 analysis revealed that the overexpression of ptr1 gene in the WTS L. braziliensis line increased 2-fold the SbIII-resistance phenotype compared to the non-transfected counterpart. Furthermore, the overexpression of ptr1 gene in the WTS L. infantum line did not change the SbIII-resistance phenotype. These results suggest that the PTR1 enzyme may be implicated in the SbIII-resistance phenotype in L. braziliensis line.
authors.affiliation: Laboratório de Parasitologia Celular e Molecular, Centro de Pesquisas René Rachou CPqRR/Fiocruz, Av. Augusto de Lima 1715, CEP 30190-002, Belo Horizonte, MG, Brazil.
authors.forename: Douglas
authors.initials: D
authors.lastname: de Souza Moreira
authors.affiliation: Laboratório de Parasitologia Celular e Molecular, Centro de Pesquisas René Rachou CPqRR/Fiocruz, Av. Augusto de Lima 1715, CEP 30190-002, Belo Horizonte, MG, Brazil.
authors.forename: Rafael Fernandes
authors.initials: RF
authors.lastname: Ferreira
authors.affiliation: Laboratório de Parasitologia Celular e Molecular, Centro de Pesquisas René Rachou CPqRR/Fiocruz, Av. Augusto de Lima 1715, CEP 30190-002, Belo Horizonte, MG, Brazil. Electronic address: silvane@cpqrr.fiocruz.br.
authors.forename: Silvane M F
authors.initials: SM
authors.lastname: Murta
mesh_terms: D000965:Antimony / Q000494:pharmacology*; D015152:Blotting, Northern; D015153:Blotting, Western; D004351:Drug Resistance; D016521:Electrophoresis, Gel, Pulsed-Field; D015971:Gene Expression Regulation, Enzymologic; D020128:Inhibitory Concentration 50; D007891:Leishmania / Q000145:classification / Q000187:drug effects / Q000201:enzymology*; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D021261:Parasitic Sensitivity Tests; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D000965:Antimony; D010088:Oxidoreductases; C085592:pteridine reductase
keywords: Antioxidant defense; Drug resistance; Leishmania; Pteridine reductase; SbIII