(A&B) The mtDNA level in PARP1+/- chagasic mice. Mice (WT and PARP1+/-) were infected with T. cruzi and monitored at 150 days’ post-infection. Representative gel images (A, n = 3 mice/group) show myocardial levels of 10 kb mtDNA and short 177-bp mtDNA and 96-bp nuDNA (GAPDH) fragments as controls. PCR amplification was performed for 28 cycles. Densitometry analysis was performed on PCR gels representing n? 6 mice/group, and density of the 10 kb mtDNA band, normalized against mtDNA and nuDNA fragments, is presented in B.a&b. (C-H) Effect of PARP1 inhibitor on cardiomyocytes infected with T. cruzi. Cardiac myocytes were infected with T. cruzi in presence or absence of PJ34 for 24 h. RT-qPCR was employed to evaluate the mRNA level for PARP1 and several components of the POLG replisome machinery, and data were normalized to GAPDH mRNA. (I-K) Cardiomyocytes were incubated for 24 with Tc in presence and absence of PJ34. ROS release was measured by an amplex red assay (I). MitoSOX red fluorescence detects mitochondrial O2•? level (J). Ratio of fluorescence intensity of J-monomers (green) to J-aggregates (red) indicates mitochondrial depolarization (K). Data in C-K were acquired by using three biological replicates (duplicate analysis per sample). Data in all bar graphs are plotted as mean value ± SEM, and statistical significance are marked as *WT.Tc vs. WT, and #WT.Tc vs. genetically-modified/infected or infected/PJ34-treated (#p<0.05, ***,###p<0.001).