Fig. 1: Mtb PtpA induces GPX4-dependent ferroptosis.
From: A mycobacterial effector promotes ferroptosis-dependent pathogenicity and dissemination
a Cell viability of U937 cells by Cell Counting Kit-8 (CCK-8) assay. WT U937 cells and U937 cells stably expressing PtpA (PtpA-U937) were treated with vehicle, 10 μM Erastin, 50 μM BSO, or 2 μM RSL3 for the indicated time periods. b Frames of Supplementary Movies 1 and 2 showing propidium iodide (PI)-positive WT U937 and PtpA-U937 cells treated with 2 μM RSL3. Dead cells (red) were stained with PI. Scale bars, 25 μm. c Confocal microscopic analysis for cell death of U937 cells. Cells were uninfected (UN) or infected with WT Mtb, Mtb ΔptpA, or Mtb ΔptpA:ptpA strain at an MOI of 10 for 24 h with the treatment of vehicle, Fer-1, or Lip-1. Mtb strains (green) were stained with Alexa FluorTM 488 succinimidyl ester, dead cells (red) were stained with PI, and nuclei (blue) were stained with DAPI. Scale bars, 25 μm. d Quantification of PI-positive infected U937 cells treated as in (c). e Flow cytometry for measurement of lipid peroxides with 1.5 μM BODIPY C11 lipid probe in U937 cells treated as in (c). f Quantification of cells with oxidative lipid ROS treated as in (c). g Heat map of genes related to GSH metabolism in U937 cells infected with WT Mtb, Mtb ΔptpA, or Mtb ΔptpA:ptpA strain at an MOI of 10 for 24 h. The genes indicated in red and blue represent upregulated and down-regulated genes, respectively. h Immunoblot analysis of GPX4, α-Tubulin, and PtpA in U937 cells treated as in (g). i Quantification of PI-positive infected U937 cells. Cells were uninfected or infected with WT Mtb, Mtb ΔptpA, or Mtb ΔptpA:ptpA strain at an MOI of 10 for 24 h with the treatment of 1 μM DOX or 10 μM Fer-1. j Quantification of cells with oxidative lipid ROS treated as in (i). Error bars are means ± SD of three groups. Statistical significance was determined using two-way ANOVA (Tukey’s multiple comparisons test). n.s., not significant. Source data are provided as a Source Data file.
