Objective: We previously showed that Campylobacter jejuni Cas9 was necessary for full virulence and efficient induction of human cell stress followed by cell death, but no virulence mechanism could be unravelled then. Therefore, we carried out global genome-wide transcriptomics, using RNA samples extracted from cells infected by a wild-type C. jejuni strain and the corresponding cas9 deletion strain.
Methods: Caco-2 epithelial cells were infected with C. jejuni wild-type or cas9 deletion strains and RNA was extracted at 5 timepoints post-infection.
Results: Wild-type C. jejuni induced cellular stress, DNA damage and cell death pathways in Caco-2 cells continuously from 30 min up to 4 hours after infection, eventually followed by visual cell death induction after 24 hours; the corresponding cas9 deletion strain did also induce cell stress pathways within the first two hours of infection but at later timepoints, stress pathway induction had dropped and after 4 hours of infection, expression of the corresponding stress genes had normalised to near-t=0 (uninfected) expression values; the cas9 deletion strain did not lead to visual cell death induction after 24 hours.
Conclusions: Campylobacter jejuni Cas9 is necessary for full virulence of C. jejuni and is involved in the efficient induction of cellular stress pathways and eventually, cell death.