Effects of mesalamine on adherent-invasive escherichia coli

Abstract

Mesalamine (5ASA) has been used for many years as a primary IBD treatment, yet the mechanism of action is not fully understood. The drug is targeted to the distal gut, thereby exposing bacteria to high concentrations of 5ASA. Considering the specific association of adherent-invasive Escherichia coli (AIEC) with this condition, we hypothesized that the therapeutic effects of 5ASA are mediated through influences on AIEC. Here, we show that 5ASA does not inhibit the growth of AIEC, but decreases AIEC's adherence to and invasion of intestinal epithelial cells. 5ASA treatment prevents the increase in adherence normally seen in inflammatory conditions. This is not due to a change in AIEC motility. 5ASA treatment increases AIEC's virulence gene (jimH,fimAv, ibeA, ompA) mRNA expression but that result did not correlate to an increase in pili expression. 5ASA affects AIEC making the bacteria less virulent, which could contribute to the therapeutic effect of 5ASA.