Journal: Emerging Microbes & Infections
Article Title: Streptococcus suis Stk1 sensitizes epithelial cells to ferroptosis and exacerbates disruption of the respiratory epithelial barrier
doi: 10.1080/22221751.2026.2627066
Figure Lengend Snippet: S. suis induces hallmark features of ferroptosis in respiratory epithelial cells. (A-J) NPTr cells were infected with SS2 (MOI = 10) or treated with the ferroptosis inducer RSL3 (1 µM) for 6 h. (A) Representative phase-contrast microscopy images showing cellular morphology. Scale bar, 100 µm. (B) Cell viability was assessed by the CCK-8 assay. (C) Intracellular labile ferrous iron (Fe 2+ ) levels were quantified using a colorimetric assay kit. (D) Reactive oxygen species (ROS) production was measured by flow cytometry analysis of H2DCFDA fluorescence. MFI, mean fluorescence intensity. (E) Lipid peroxidation was visualized by confocal microscopy using the C11-BODIPY 581/591 probe. Scale bar, 10 µm. (F) Quantification of lipid peroxidation by measuring C11-BODIPY fluorescence using a plate reader. (G) Malondialdehyde (MDA) levels were quantified using a thiobarbituric acid reactive substances (TBARS) assay. (H) Western blot analysis of 4-hydroxynonenal (4-HNE) protein adducts. (I) Mitochondrial ultrastructure was analysed by transmission electron microscopy. Arrows indicate shrunken mitochondria with loss of cristae. Scale bars, 2 µm (main image) and 500 nm (inset). (J) Cell death was quantified by measuring propidium iodide (PI) fluorescence. All quantitative data are represented as mean ± SD from triplicate independent experiments. Statistical significance was determined by one-way ANOVA test (* p < 0.05; ** p < 0.01; *** p < 0.001, ns, no significant).
Article Snippet: The intracellular Fe 2+ concentration was determined using the Cell Ferrous Ion Colorimetric Assay Kit (Elabscience, E-BC-K881-M), and absorbance was measured at 593 nm with a Spark multi-functional microplate reader (Tecan).
Techniques: Infection, Microscopy, CCK-8 Assay, Colorimetric Assay, Flow Cytometry, Fluorescence, Confocal Microscopy, TBARS Assay, Western Blot, Transmission Assay, Electron Microscopy