Colon-specific delivery of a probiotic-derived soluble protein ameliorates intestinal inflammation in mice through an EGFR-dependent mechanism
Fang Yan, … , Keith T. Wilson, D. Brent Polk
Fang Yan, … , Keith T. Wilson, D. Brent Polk
Published May 23, 2011
Citation Information: J Clin Invest. 2011;121(6):2242-2253. https://doi.org/10.1172/JCI44031.
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Research Article

Colon-specific delivery of a probiotic-derived soluble protein ameliorates intestinal inflammation in mice through an EGFR-dependent mechanism

Abstract

Probiotic bacteria can potentially have beneficial effects on the clinical course of several intestinal disorders, but our understanding of probiotic action is limited. We have identified a probiotic bacteria–derived soluble protein, p40, from Lactobacillus rhamnosus GG (LGG), which prevents cytokine-induced apoptosis in intestinal epithelial cells. In the current study, we analyzed the mechanisms by which p40 regulates cellular responses in intestinal epithelial cells and p40’s effects on experimental colitis using mouse models. We show that the recombinant p40 protein activated EGFR, leading to Akt activation. Activation of EGFR by p40 was required for inhibition of cytokine-induced apoptosis in intestinal epithelial cells in vitro and ex vivo. Furthermore, we developed a pectin/zein hydrogel bead system to specifically deliver p40 to the mouse colon, which activated EGFR in colon epithelial cells. Administration of p40-containing beads reduced intestinal epithelial apoptosis and disruption of barrier function in the colon epithelium in an EGFR-dependent manner, thereby preventing and treating DSS-induced intestinal injury and acute colitis. Furthermore, p40 activation of EGFR was required for ameliorating colon epithelial cell apoptosis and chronic inflammation in oxazolone-induced colitis. These data define what we believe to be a previously unrecognized mechanism of probiotic-derived soluble proteins in protecting the intestine from injury and inflammation.

Authors

Fang Yan, Hanwei Cao, Timothy L. Cover, M. Kay Washington, Yan Shi, LinShu Liu, Rupesh Chaturvedi, Richard M. Peek Jr., Keith T. Wilson, D. Brent Polk

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Figure 6

EGFR kinase activity is required for p40-mediated inhibition of DSS-induced colon epithelial cell apoptosis.

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EGFR kinase activity is required for p40-mediated inhibition of DSS-indu...
(A) Mice were treated with DSS for 7 days and were gavaged with pectin/zein beads only or beads containing p40 at 10 μg/mouse/d, beginning on the same day of DSS treatment until the end of the experiment, as described in Figure 4. Paraffin-embedded tissue sections were analyzed using ISOL staining to detect apoptosis. Apoptotic nuclei labeled with peroxidase were visualized using DIC microcopy. Arrows indicate ISOL-labeled apoptotic nuclei (brown). Original magnification, ×40. (B) The number of apoptotic nuclei per 100 crypts is shown. (C) Colon epithelial cells were isolated for Western blot analysis to detect active caspase-3, Bcl-2, and Bax expression. The lanes in C were run on the same gel but were noncontiguous, as indicated by the white lines. (D) The relative densities of protein bands on Western blots were determined by comparing densities of active caspase-3, Bcl-2, or Bax to that of the actin bands. The relative density of bands from the control (water-treated) group was set as 100%, and the relative densities of bands from DSS-treated mice were compared with those in the water-treated group. n = 5–7 mice for each condition. *P < 0.01 compared with water groups in WT or Egfrwa2 mice; #P < 0.01 compared with either WT mice treated with DSS or WT mice treated with DSS and control beads.