Figure 5.

Salmonella infection can increase endoreticular membranes and exhibit altered cellular location in the presence of HLA-B27. (A) Increase in the number of intracellular bacteria in cells treated with UPR-inducing drugs is dependent on the intracellular replication of bacteria within the SCV. HeLa cells were treated with DMSO or 200 nM TPG at 16 hours prior to infection with Salmonella enterica Typhimurium 12 023 or ΔsifA strains expressing mCherry. Wild-type (WT) bacteria, which replicate within the SCV, show increases in intracellular bacteria in the TPG-treated samples, while those infected with the ΔsifA mutant show no increase in the TPG-treated cells. (B) HeLa cells were infected with WT or ΔsifA ST.mCherry, stained with ER tracker (green) at 4 and 24 hours pi and analysed by confocal microscopy using an Opera LX plate reader. Quantification of endoreticular membrane content in infected cells. MFI of glibenclamide staining in infected (INF) and non-infected (NI) cells were compared at 4 and 24 hours pi with either WT or ΔsifA 12023. MFI values±SEM are shown (n=135–1476). For (B) statistical analysis was performed using the Kruskal-Wallis test (p<0.0001) and was performed with Dunn’s multiple comparison post-test to determine significant differences between individual groups (***p<0.001). DMSO, dimethyl sulfoxide; ER, endoplasmic reticulum; HeLa, Henrietta Lacks; HLA, human leucocyte antigen; MFI, mean fluorescence intensity; pi, postinfection; SCV, Salmonella-containing vacuole; TPG, thapsigargin; UPR, unfolded protein response.