Impact of Quorum Sensing Signal N-3-Oxododecanoyl Homoserine Lactone on Intestinal Porcine Enterocyte Cell

Abstract

Quorum sensing (QS) is an autoinducer (AI) molecules mediated signaling system in bacteria. It is generally believed that bacteria can regulate their own characteristics or virulence through OS. This study investigated the direct effects of a quorum sensing signal molecule N-3-oxododecanoyl homoserine lactone (3OC12-HSL, synonyms: OdDHL) on host cells, to further reveal the function of QS system in the interaction between bacteria and host cells. Intestinal porcine enterocyte cell line (IPEC-J2) were used as model cells, and the AHL signal molecule OdDHL was used to stimulate the cells to observe the effect of quorum sensing signals on host cells. The results showed that OdDHL had an obvious effect on the morphology of IPEC-J2 cells, and a lower concentration and shorter time of stimulation could induce cell shrinkage and rounding. MTT assay revealed that OdDHL had no effect on IPEC-J2 cell viability, suggesting that the cell morphological changes were not from signaling molecule toxicity. Using different concentrations and different exposure times of OdDHL to stimulate IPEC-J2 cells, we demonstrated that changes in cell morphology were positively correlated with the concentration of AHL and exposure time. Bacterial adhesion assay showed that OdDHL could enhance the adhesion of enteropathogenic E. coli to host cell IPEC-J2, while reducing its invasion into host cell. Fluorescent quantitative PCR and Western blot revealed that the expression of tight junction protein ZO-1 was significantly increased. The expression levels of multiple genes that related to cytoskeletons and cell junction were all regulated by OdDHL. In conclusion, OdDHL could directly affect the biological characteristics of IPEC-J2 cells such as morphology and tight junction, reduce the intestinal defences of hosts, thereby promoting the adhesion and injury of pathogenic bacteria to the intestine of piglets. This study provides a basic reference for further understanding of the pathogenic role of regulating pathogenic bacterial populations and their prevention against diseases.