Probiotics inhibit nuclear factor-κB and induce heat shock proteins in colonic epithelial cells through proteasome inhibition

EO Petrof, K Kojima, MJ Ropeleski, MW Musch, Y Tao… - Gastroenterology, 2004 - Elsevier
EO Petrof, K Kojima, MJ Ropeleski, MW Musch, Y Tao, C De Simone, EB Chang
Gastroenterology, 2004Elsevier
Background & Aims: The extent and severity of mucosal injury in inflammatory bowel
diseases are determined by the disequilibrium between 2 opposing processes: reparative
and cytoprotective mechanisms vs. inflammation-induced injury. Probiotics may provide
clinical benefit by ameliorating colitis; however, their mechanisms of action remain largely
unknown. Our objective was to investigate microbial-epithelial interactions that could explain
the beneficial therapeutic effects of probiotics. Methods: The effect of VSL# 3-conditioned …
Background & Aims
The extent and severity of mucosal injury in inflammatory bowel diseases are determined by the disequilibrium between 2 opposing processes: reparative and cytoprotective mechanisms vs. inflammation-induced injury. Probiotics may provide clinical benefit by ameliorating colitis; however, their mechanisms of action remain largely unknown. Our objective was to investigate microbial-epithelial interactions that could explain the beneficial therapeutic effects of probiotics.
Methods
The effect of VSL#3-conditioned media on the nuclear factor-κB pathway in young adult mouse colonic epithelial cells was assessed by using monocyte chemoattractant protein-1 enzyme-linked immunosorbent assays; IκBα, IκBβ, and p105 immunoblot analysis; and nuclear factor-κB luciferase reporter gene and proteasome assays. Effects on heat shock proteins were determined by electrophoretic mobility shift assay and immunoblot for heat shock proteins 25 and 72 in young adult mouse colonic cells. Cytoprotection against oxidant injury was determined by chromium 51 release and filamentous and globular actin assays.
Results
VSL#3 produces soluble factors that inhibit the chymotrypsin-like activity of the proteasome in gut epithelial cells. Proteasome inhibition is an early event that begins almost immediately after exposure of the epithelial cells to the probiotic-conditioned media. In addition, these bacteria inhibit the proinflammatory nuclear factor-κB pathway through a mechanism different from the type III secretory mechanisms described for other nonpathogenic enteric flora. They also induce the expression of cytoprotective heat shock proteins in intestinal epithelial cells.
Conclusions
The resulting inhibition of nuclear factor-κB and increased expression of heat shock proteins may account for the anti-inflammatory and cytoprotective effects reported for probiotics and may be a novel mechanism of microbial-epithelial interaction. These effects seem to be mediated through the common unifying mechanism of proteasome inhibition.
Elsevier