Virulence Factors of Pseudomonas aeruginosa Induce Both the Unfolded Protein and Integrated Stress Responses in Airway Epithelial Cells
Fig 7
GADD34 mRNA is regulated via the activation of the integrated stress response by P. aeruginosa.
B-G. Gadd34 mRNA normalised expression in Perk-/-, eIF2αAA, Atf4-/-, Pkr-/-, Gcn2-/- and Hri-/- mouse embryonic fibroblasts (MEFs) exposed to CM-PAO1 for 8, 16 or 24 hours or tunicamycin (Tm) for 6 hours as a positive control (n = 3; mean ± SEM). All values are normalised to the housekeeping genes Actb and Sdha. H. GADD34 mRNA levels in HeLa cells upon exposure to CM-PAO1 after knock-down of GCN2 or HRI with siRNA (n = 3; mean ± SEM). All values are normalised to the housekeeping genes RPL13A and ATP5B. I. Normalised expression values of spliced XBP1, CHOP, GADD34 and GRP78 mRNA in 16HBE cells after stimulation with 1–100 nM deferoxamine (DFO). All values are normalised to the housekeeping genes RPL13A and ATP5B. J. Gadd34 mRNA levels in wild-type MEFs after repletion of the cell culture medium with iron (Fe3+) when treated with CM-PAO1 (n = 3; mean ± SEM). The first column (- Fe3+,—CM-PAO1) reflects medium control cells, without adding or depleting iron from the cell culture medium. All values are normalised to the housekeeping genes Actb and Sdha. * p<0.05, ** p<0.01, *** p<0.001 versus untreated (-) with a two-way repeated-measurements ANOVA (Bonferroni post-hoc).