Haemophilus parasuis infection activates chemokine RANTES in PK-15 cells

- The pathogen of Glässer's disease of pigs H. parasuis activated RANTES expression.
- H. parasuis-induced RANTES transcription required multiple cis elements.
- NF-κB and JNK MAPK pathways were involved in H. parasuis-induced RANTES expression.
- TLRs signaling cascades were involved in H. parasuis-induced RANTES expression.

RANTES is a member of the CC chemokine involved in inflammation and immune response during pathogen infection. In our previous study, Haemophilus parasuis (H. parasuis), which is responsible for the great economic losses in the pig industry worldwide, has been shown to enhance RANTES expression in PK-15 cells. However, the mechanisms behind this biological phenomenon have remained unclear. In this study, we showed that H. parasuis infection significantly upregulated RANTES gene transcription in a time- and dose-dependent manner. Promoter analysis by site-directed mutagenesis indicated that the nuclear factor NF-κB binding site was the most important cis-regulatory element controlling H. parasuis-induced RANTES transcription. Inhibition of NF-κB and JNK activity also significantly reduced H. parasuis-induced RANTES production. In addition, TLRs signaling pathway was found to be involved in H. parasuis induced-RANTES expression. These results represent an important molecular mechanism whereby H. parasuis induced RANTES in the inflammatory response.