Effects of buthionine sulfoximine nifurtimox and benznidazole upon trypanothione and metallothionein proteins in Trypanosoma cruzi.

Juan Diego Maya,Laura Pino,Adriana Pabón,Mario Pavani,Antonio Morello,Yolanda Repetto,Andrés Rodríguez,Jorge Ferreira

doi:10.4067/s0716-97602004000100007

Juan Diego Maya, Laura Pino + Show 6 more

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https://doi.org/10.4067/s0716-97602004000100007

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Abstract

Proteins rich in sulfhydryl groups, such as metallothionein, are present in several strains of the parasite Trypanosoma cruzi, the etiological agent of Chagas' disease. Metallothionein-like protein concentrations ranged from 5.1 to 13.2 pmol/mg protein depending on the parasite strain and growth phase. Nifurtimox and benznidazole, used in the treatment of Chagas' disease, decreased metallothionein activity by approximately 70%. T. cruzi metallothionein was induced by ZnCl2. Metallothionein from T. cruzi was partially purified and its monobromobimane derivative showed a molecular weight of approximately 10,000 Da by SDS-PAGE analysis. The concentration of trypanothione, the major glutathione conjugate in T. cruzi, ranged from 3.8 to 10.8 nmol/mg protein, depending on the culture phase. The addition of buthionine sulfoximine to the protozoal culture considerably reduced the concentration of trypanothione and had no effect upon the metallothionein concentration. The possible contribution of metallothionein-like proteins to drug resistance in T. cruzi is discussed.

Highlights

Several thiol-containing molecules play an important role in trypanosomatid defense against free radicals and electrophilic agents
Metallothionein-like protein concentrations ranged from 5.1 to 13.2 pmol/mg protein depending on the parasite strain and growth phase
Metallothionein from T. cruzi was partially purified and its monobromobimane derivative showed a molecular weight of approximately 10,000 Da by SDS-PAGE analysis

Summary

Introduction

Several thiol-containing molecules play an important role in trypanosomatid defense against free radicals and electrophilic agents. The most important thiol molecules are trypanothione (bis-glutathionyl spermidine, T(SH)2), glutathione (GSH), ovothiols (Fairlamb and Cerami, 1985; Steenkamp and Spies, 1994; Repetto et al, 1996; Maya et al, 1997; Maya et al, 1999; Maya et al, 2001a; Ariyanayagam and Fairlamb, 2001; Steenkamp, 2002), and metallothionein-like proteins (MTs), as shown in this paper. All these compounds act as free radical scavengers by virtue of their thiol groups. MTs appear to be mainly cytoplasmic but several studies have shown that these proteins are present in nuclei (Jeremias and Kägi, 1991; Sato and Bremner, 1993)

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