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Mannosyltransferase (GPI-14) overexpression protects promastigote and amastigote forms of Leishmania braziliensis against trivalent antimony

Ribeiro, Christiana Vargas, Rocha, Bruna Fonte Boa, Moreira, Douglas de Souza, Peruhype-Magalhães, Vanessa, Murta, Silvane Maria Fonseca
Parasites & vectors 2019 v.12 no.1 pp. 60
Leishmania braziliensis, amastigotes, antimony, clones, concanavalin A, fluorescence, gene overexpression, genes, glucose, host-parasite relationships, macrophages, mannose, messenger RNA, moieties, parasites, phenotype, promastigotes, quantitative polymerase chain reaction, reverse transcriptase polymerase chain reaction, transferases
BACKGROUND: Glycosylphosphatidylinositol is a surface molecule important for host-parasite interactions. Mannosyltransferase (GPI-14) is an essential enzyme for adding mannose on the glycosylphosphatidyl group. This study attempted to overexpress the GPI-14 gene in Leishmania braziliensis to investigate its role in the antimony-resistance phenotype of this parasite. RESULTS: GPI-14 mRNA levels determined by quantitative real-time PCR (qRT-PCR) showed an increased expression in clones transfected with GPI-14 compared to its respective wild-type line. In order to investigate the expression profile of the surface carbohydrates of these clones, the intensity of the fluorescence emitted by the parasites after concanavalin-A (a lectin that binds to the terminal regions of α-D-mannosyl and α-D-glucosyl residues) treatment was analyzed. The results showed that the clones transfected with GPI-14 express 2.8-fold more mannose and glucose residues than those of the wild-type parental line, indicating effective GPI-14 overexpression. Antimony susceptibility tests using promastigotes showed that clones overexpressing the GPI-14 enzyme are 2.4- and 10.5-fold more resistant to potassium antimonyl tartrate (Sbᴵᴵᴵ) than the parental non-transfected line. Infection analysis using THP-1 macrophages showed that amastigotes from both GPI-14 overexpressing clones were 3-fold more resistant to Sbᴵᴵᴵ than the wild-type line. CONCLUSIONS: Our results suggest the involvement of the GPI-14 enzyme in the Sbᴵᴵᴵ-resistance phenotype of L. braziliensis.