Differential roles of Yersinia outer protein P-mediated inhibition of nuclear factor-kappa B in the induction of cell death in dendritic cells and macrophages.

Yersinia outer protein P (YopP) induces cell death in macrophages and dendritic cells (DC). In DC this YopP-dependent cell death coincides with the inhibition of nuclear factor-kappa B (NF-kappa B) activation. However, as shown by measurement of propidium iodide uptake via disrupted cellular membranes, the preincubation of DC, with several NF-kappa B inhibitors prior to infection with Yersinia did not restore the death-inducing capacity of a YopP-deficient Yersinia mutant. These results suggest that in contrast to macrophages, in DC the YopP-dependent inhibition of NF-kappa B activation is not causative for the induction of cell death. Instead, in DC, the inhibition of mitogen-activated protein kinases (MAPKs), in particular, p38 and c-Jun N-terminal kinase, prior to infection with a YopP-deficient Yersinia mutant substituted the death-inducing capacity of the Yersinia wild-type strain, indicating that the YopP-dependent inhibition of MAPKs mediates Yersinia-induced DC death. The differences between DC and macrophages in the mechanisms of cell death induction by YopP presented herein might be crucial for the function of these antigen-presenting cells.