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Catalase expression impairs oxidative stress-mediated signalling in Trypanosoma cruzi

2017; Cambridge University Press; Volume: 144; Issue: 11 Linguagem: Inglês

10.1017/s0031182017001044

1469-8161

Anna Cláudia Guimarães Freire, Ceres Luciana Alves, Grazielle Ribeiro Goes, Bruno Carvalho Resende, Nilmar Silvio Moretti, Vinícius Santana Nunes, Pedro Henrique Nascimento de Aguiar, Erich Birelli Tahara, Glória Regina Franco, Andréa Mara Macedo, Sérgio Danilo Junho Pena, Fernanda Ramos Gadelha, Alessandra A. Guarneri, Sérgio Schenkman, Leda Quércia Vieira, Carlos Renato Machado,

Calcium signaling and nucleotide metabolism

Trypanosoma cruzi is exposed to oxidative stresses during its life cycle, and amongst the strategies employed by this parasite to deal with these situations sits a peculiar trypanothione-dependent antioxidant system. Remarkably, T. cruzi's antioxidant repertoire does not include catalase. In an attempt to shed light on what are the reasons by which this parasite lacks this enzyme, a T. cruzi cell line stably expressing catalase showed an increased resistance to hydrogen peroxide (H2O2) when compared with wild-type cells. Interestingly, preconditioning carried out with low concentrations of H2O2 led untransfected parasites to be as much resistant to this oxidant as cells expressing catalase, but did not induce the same level of increased resistance in the latter ones. Also, presence of catalase decreased trypanothione reductase and increased superoxide dismutase levels in T. cruzi, resulting in higher levels of residual H2O2 after challenge with this oxidant. Although expression of catalase contributed to elevated proliferation rates of T. cruzi in Rhodnius prolixus, it failed to induce a significant increase of parasite virulence in mice. Altogether, these results indicate that the absence of a gene encoding catalase in T. cruzi has played an important role in allowing this parasite to develop a shrill capacity to sense and overcome oxidative stress.