Lactobacillus acidophilus S-layer protein-mediated inhibition of Salmonella-induced apoptosis in Caco-2 cells.

Abstract

Surface layer (S-layer) proteins are crystalline arrays of proteinaceous subunits present as the outermost component of the cell wall in several Lactobacillus species. The underlying mechanism for how S-layer proteins inhibit pathogen infections remains unclear. To gain insights into the mechanism of the antimicrobial activity of Lactobacillus S-layer proteins, we examined how Lactobacillus S-layer proteins impact Salmonella Typhimurium-induced apoptosis in vitro in Caco-2 human colon epithelial cells. When Caco-2 cells infected with Salmonella Typhimurium SL1344, we found that apoptosis was mediated by activation of caspase-3, but not caspase-1. When Salmonella Typhimurium SL1344 and S-layer proteins were coincubated simultaneously, Caco-2 cell apoptosis was markedly decreased and the cell damage was modified, as evaluated by flow cytometry and microscopy. Detailed analyses showed that the S-layer proteins inhibited the caspase-3 activity and activated the extracellular signal-regulated kinases 1 and 2 (ERK1/2) signaling pathway. Taken together, these findings suggest that Lactobacillus S-layer proteins protected against Salmonella-induced apoptosis through reduced caspase-3 activation. In addition, Salmonella-induced apoptotic cell damage was modified by S-layer proteins through the ERK1/2 signaling pathway. This mechanism may represent a novel approach for antagonizing Salmonella infection.

• Authors: Pengcheng Li, Yinyan Yin, Qinghua Yu, Qian Yang
• Journal: Biochemical and biophysical research communications (Biochem Biophys Res Commun) Vol. 409 Issue 1 Pg. 142-7 (May 27 2011) ISSN: 1090-2104 [Electronic] United States
• PMID: 21557929 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2011 Elsevier Inc. All rights reserved.

Chemical References

• Anti-Bacterial Agents
• Membrane Glycoproteins
• S-layer proteins
• Caspase 3

Topics

• Anti-Bacterial Agents (pharmacology)
• Apoptosis (drug effects)
• Caco-2 Cells
• Caspase 3 (metabolism)
• Humans
• Intestinal Mucosa (microbiology)
• Lactobacillus acidophilus
• Membrane Glycoproteins (pharmacology)
• Salmonella typhimurium (drug effects)