Oxidative stress fuels Trypanosoma cruzi infection in mice
Claudia N. Paiva, Daniel F. Feijó, Fabianno F. Dutra, Vitor C. Carneiro, Guilherme B. Freitas, Letícia S. Alves, Jacilene Mesquita, Guilherme B. Fortes, Rodrigo T. Figueiredo, Heitor S.P. Souza, Marcelo R. Fantappié, Joseli Lannes-Vieira, Marcelo T. Bozza
Claudia N. Paiva, Daniel F. Feijó, Fabianno F. Dutra, Vitor C. Carneiro, Guilherme B. Freitas, Letícia S. Alves, Jacilene Mesquita, Guilherme B. Fortes, Rodrigo T. Figueiredo, Heitor S.P. Souza, Marcelo R. Fantappié, Joseli Lannes-Vieira, Marcelo T. Bozza
View: Text | PDF
Research Article

Oxidative stress fuels Trypanosoma cruzi infection in mice

Abstract

Oxidative damage contributes to microbe elimination during macrophage respiratory burst. Nuclear factor, erythroid-derived 2, like 2 (NRF2) orchestrates antioxidant defenses, including the expression of heme-oxygenase–1 (HO-1). Unexpectedly, the activation of NRF2 and HO-1 reduces infection by a number of pathogens, although the mechanism responsible for this effect is largely unknown. We studied Trypanosoma cruzi infection in mice in which NRF2/HO-1 was induced with cobalt protoporphyrin (CoPP). CoPP reduced parasitemia and tissue parasitism, while an inhibitor of HO-1 activity increased T. cruzi parasitemia in blood. CoPP-induced effects did not depend on the adaptive immunity, nor were parasites directly targeted. We also found that CoPP reduced macrophage parasitism, which depended on NRF2 expression but not on classical mechanisms such as apoptosis of infected cells, induction of type I IFN, or NO. We found that exogenous expression of NRF2 or HO-1 also reduced macrophage parasitism. Several antioxidants, including NRF2 activators, reduced macrophage parasite burden, while pro-oxidants promoted it. Reducing the intracellular labile iron pool decreased parasitism, and antioxidants increased the expression of ferritin and ferroportin in infected macrophages. Ferrous sulfate reversed the CoPP-induced decrease in macrophage parasite burden and, given in vivo, reversed their protective effects. Our results indicate that oxidative stress contributes to parasite persistence in host tissues and open a new avenue for the development of anti–T. cruzi drugs.

Authors

Claudia N. Paiva, Daniel F. Feijó, Fabianno F. Dutra, Vitor C. Carneiro, Guilherme B. Freitas, Letícia S. Alves, Jacilene Mesquita, Guilherme B. Fortes, Rodrigo T. Figueiredo, Heitor S.P. Souza, Marcelo R. Fantappié, Joseli Lannes-Vieira, Marcelo T. Bozza

×

Figure 7

Cellular iron is mobilized by oxidative stress and fuels T. cruzi infection.

Options: View larger image (or click on image) Download as PowerPoint
Cellular iron is mobilized by oxidative stress and fuels T. cruzi infect...
(A) Antioxidants increase H-ferritin (H-Ft) and FPN1 expression (immunoblot). Extracts were prepared from infected thioglycollate-elicited peritoneal macrophages treated for 12 hours with CoPP, NAC, or apocynin. (B) Antioxidants reduce the labile iron pool. The quenching of calcein fluorescence was measured by flow cytometry as an indicator of labile iron. Thioglycollate-elicited peritoneal macrophages were infected in vitro and left untreated (–) or treated for 6 hours with antioxidants (CoPP, NAC, apocynin) with or without Fe2+. (C) Parasite burden in THP-1 cells transfected with H-ferritin or mutant nonfunctional ferritin (Mu) 48 hours after infection. Parasite burden in thioglycollate-elicited peritoneal macrophages infected in vitro and left untreated (–) or treated with (D) apo-ferritin (apo-Ft); (E) DFO; Fe2SO4 alone or (F) added to IL-6, (G) dorsomorphin (dorso), (H) CoPP, (I) NAC, or (J) apocynin for 48 hours. (K) Parasite burden in thioglycollate-elicited peritoneal macrophages taken from wild-type or gp91phox–/– mice infected in vitro and treated with Fe2SO4 for 48 hours. Effects of treatment with CoPP and Fe2SO4 on (L) mean parasitemia and (M) survival of mice (n = 8–10). Error bars represent SEM. In C–K, cells were stained with Giemsa, and amastigotes were counted in each of 100 infected cells and expressed as mean ± SEM. Experiments were performed at least twice. *P < 0.05 compared with infected untreated wild-type controls; #P < 0.05 compared with IL-6– (F), dorsomorphin- (G), CoPP- (H), NAC- (I), or apocynin-treated cells (J); †P < 0.05 compared with infected knockout mice. Scale bars: 20 μm.