Plasmodium berghei-Mediated NRF2 Activation in Infected Hepatocytes Enhances Parasite Survival

Figure 4

NRF2 activation counteracts ROS generation in P. berghei infected cells. (a) HuH7 WT cells stably expressing roGFP2 in the cytoplasm were treated with different concentrations of H₂O₂ to induce oxidative stress. Single cells were imaged once with excitation 405 nm and once with excitation 488 nm with the same detection range of 500 nm to 550 nm. Signal intensities for both excitation wavelengths were measured using FIJI. The graph depicts the ratio of both signal intensities which each dot representing one single cell. per condition. Graph shows mean and SD. -values were calculated using a one-way ANOVA test followed by Tukey’s post hoc test ( and ). (b) Nontreated HuH7 roGFP cells were imaged, then treated with first 100 μM H₂O₂ and sequentially reduced again with growth medium containing DTT at different concentrations. The same cells were followed over the different treatments. . The significance to the respective previous treatment was calculated using a Student’s -test (ns: and ). (c) HuH7 WT and NRF2^-/- cells stably expressing roGFP2 in their cytoplasm were infected with PbmCherry. 6 hpi, infected and noninfected cells were imaged using confocal microscopy. Each cell was imaged once with excitation 405 nm and once with excitation 488 nm with the same detection range of 500 nm to 550 nm. Signal intensities for both excitation wavelengths were measured using FIJI. The graph shows the ratio exc405/exc488 with each dot representing one single cell. in wildtype cells and in NRF2^-/- cells. -values were determined using a Student’s -test ( and ). (d) HuH7 WT cells stably expressing roGFP2 were infected with PbmCherry. 6 hpi, infected and noninfected cells that were either left untreated or treated with different concentrations of H₂O₂ were imaged as described above. The graph depicts the ratio of signal intensity with excitation 405 nm divided by signal intensity at excitation 488 nm. Each dot represents one single cell. The experiment was carried out twice with per condition. One representative experiment is shown. Significance was determined by Student’s -test (ns: ; ; and ). Note that different scales were used in (a),(c), and (d) for optimal display of small differences.

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