The role of p-glycoprotein in bacterial attachment to intestinal cells.

Abstract

This study investigated the effect of changes to P-glycoprotein function and expression on bacterial attachment to Caco2 and RKO gastrointestinal cells using 6 species of bacteria (E. coli, Staph. aureus, Salmonella typhimurium, Klebsiella aerogenes, Clostridium sporogenes or Pseudomonas aeruginosa). The RKO cell line was chosen to provide a cell line with minimal P-gp expression. Following incubation of gastrointestinal cells with the P-gp inhibitors, bacteria incubated with a stable fluorescent dye (BacLight Green) were added and incubated at 37C for various times between 30 and 240 min. Fluorescence intensity corrected for background was used to compare bacterial attachment to these cell lines with either the P-gp inhibited, induced (using rifampicin) or normal expression. It was found that P-gp inhibition resulted in a significant increase of all bacterial attachment to Caco2 cells. PSC-833 incubation resulted in Pseudomonas attachment increasing by 65%, while E. coli resulted in a doubling of attached bacteria. Salmonella, Klebsiella, Staphlococcus, and Clostridium had up to a 3 fold increased attachment in Caco-2 cells.RKO cells did not alter their bacterial attachment with PSC-833. Western blotting confirmed the presence of P-gp in Caco-2 cells, and absence in RKO cells. In addition, rifampicin, a P-gp inducer, resulted in a reduction in Salmonella and Klebsiella attachment of up to 50%. These results suggest P-gp expression may contribute to the resistance of potential bacterial toxicity in the gut, by preventing them accumulating, which in turn reduces the risk of gastrointestinal disorders.