The mitochondrial uncoupler 2,4-dinitrophenol modulates inflammatory and oxidative responses in Trypanosoma cruzi-induced acute myocarditis in mice.

By uncoupling oxidative phosphorylation, 2,4-dinitrophenol (DNP) attenuates reactive oxygen species (ROS) biosynthesis, which are known to aggravate infectious myocarditis in Chagas disease. Thus, the impact of DNP-based chemotherapy on Trypanosoma cruzi-induced acute myocarditis was investigated. C56BL/6 mice uninfected and infected untreated and treated daily with 100 mg/kg benznidazole (Bz, reference drug), 5 and 10 mg/kg DNP by gavage for 11 days after confirmation of T. cruzi infection were investigated. Twenty-four hours ​after the last treatment, the animals were euthanized and the heart was collected for microstructural, immunological and biochemical analyses. T. cruzi inoculation induced systemic inflammation (e.g., cytokines and anti-T. cruzi IgG upregulation), cardiac infection (T. cruzi DNA), oxidative stress, inflammatory infiltrate and microstructural myocardial damage in untreated mice. DNP treatment aggravated heart infection and microstructural damage, which were markedly attenuated by Bz. DNP (10 mg/kg) was also effective in attenuating ROS (total ROS, H2O2, and O2-), nitric oxide (NO), lipid (malondialdehyde - MDA) and protein (protein carbonyl - PCn) oxidation, TNF, IFN-γ, IL-10, and MCP-1/CCL2, anti-T. cruzi IgG, cardiac troponin I levels, as well as inflammatory infiltrate and cardiac damage in T. cruzi-infected mice. Our findings indicate that DNP aggravated heart infection and microstructural cardiomyocytes damage in infected mice. These responses were related to the antioxidant and anti-inflammatory properties of DNP, which favors infection by weakening the pro-oxidant and pro-inflammatory protective mechanisms of the infected host. Conversely, Bz-induced cardioprotective effects combined effective anti-inflammatory and antiparasitic responses, which protect against heart infection, oxidative stress, and microstructural damage in Chagas disease.

Identification of host antioxidant effectors as thioridazine targets: Impact on cardiomyocytes infection and Trypanosoma cruzi-induced acute myocarditis.

Phenothiazines inhibit antioxidant enzymes in trypanosomatids. However, potential interferences with host cell antioxidant defenses are central concerns in using these drugs to treat Trypanosoma cruzi-induced infectious myocarditis. Thus, the interaction of thioridazine (TDZ) with T. cruzi and cardiomyocytes antioxidant enzymes, and its impact on cardiomyocytes and cardiac infection was investigated in vitro and in vivo. Cardiomyocytes and trypomastigotes in culture, and mice treated with TDZ and benznidazole (Bz, reference antiparasitic drug) were submitted to microstructural, biochemical and molecular analyses. TDZ was more cytotoxic and less selective against T. cruzi than Bz in vitro. TDZ-pretreated cardiomyocytes developed increased infection rate, reactive oxygen species (ROS) production, lipid and protein oxidation; similar catalase (CAT) and superoxide dismutase (SOD) activity, and reduced glutathione's (peroxidase - GPx, S-transferase - GST, and reductase - GR) activity than infected untreated cells. TDZ attenuated trypanothione reductase activity in T. cruzi, and protein antioxidant capacity in cardiomyocytes, making these cells more susceptible to H2O2-based oxidative challenge. In vivo, TDZ potentiated heart parasitism, total ROS production, myocarditis, lipid and protein oxidation; as well as reduced GPx, GR, and GST activities compared to untreated mice. Benznidazole decreased heart parasitism, total ROS production, heart inflammation, lipid and protein oxidation in T. cruzi-infected mice. Our findings indicate that TDZ simultaneously interact with enzymatic antioxidant targets in cardiomyocytes and T. cruzi, potentiating the infection by inducing antioxidant fragility and increasing cardiomyocytes and heart susceptibility to parasitism, inflammation and oxidative damage.