Immortalized Human Pancreatic Duct Epithelial Cells-HPV16 E6/E7

Invasion of Pancreatic Ductal Epithelial Cells by Enterococcus Faecalis is Mediated by Fibronectin and Enterococcal Fibronectin-Binding Protein A

To examine the potential pathogenic role of E. faecalis in pancreas, we evaluated adhesion to immortalized normal human pancreatic ductal epithelial cells (iPDECs). Two E. faecalis strains were used to evaluate adhesion: JCM7783 and OU1. Both strains exhibited adhesion to iPDECs that persisted even after thorough washing steps, with the OU1 strain adhering to a greater extent.

Next, we examined entry of E. faecalis into iPDECs following adhesion. Image analysis confirmed that E. faecalis entered the cytoplasm of iPDECs. E. faecalis invasion of iPDECs was quantified using an invasion assay. The results demonstrated that both strains of E. faecalis entered iPDECs, with the highly adhesive OU1 strain invading to a greater extent than the JCM7783 strain. Cellular invasion by E. faecalis was also confirmed in three additional pancreatic ductal epithelial lineage cell lines: BxPC3, MIA PaCa-2, and PSN1.

Mechanistically, bacterial expression of enterococcal fibronectin-binding protein A (EfbA) was correlated with adhesive potential of E. faecalis strains. Knockout of fibronectin 1, a binding partner of EfbA, in iPDECs resulted in suppressed E. faecalis adhesion and invasion, suggesting the importance of the EfbA-fibronectin axis in infection of pancreatic ductal epithelial lineage cells. Overall, these results suggest that E. faecalis can colonize pancreatic tissue by infecting iPDECs, at least in part, via the expression of the cell adhesion factor EfbA.