title: Lactobacillus S-layer protein inhibition of Salmonella-induced reorganization of the cytoskeleton and activation of MAPK signalling pathways in Caco-2 cells.
abstract: Surface layer (S-layer) proteins are crystalline arrays of proteinaceous subunits that are present as the outermost component of the cell wall in several Lactobacillus species. The S-layer proteins have been shown to play a role in the antimicrobial activity of certain lactobacilli. However, it is not fully understood how the S-layer proteins exert this biological function. The aim of this study was to test the hypothesis that Lactobacillus acidophilus S-layer proteins antagonize Salmonella Typhimurium (S. Typhimurium) infection by protecting against F-actin cytoskeleton rearrangements and the activation of mitogen-activated protein kinase (MAPK) signalling pathways. Monolayer transepithelial electrical resistance (TER) was measured after S. Typhimurium infection in Caco-2 cultured human intestinal cells with L. acidophilus S-layer proteins. F-actin rearrangement and MAPK activation were also assessed by immunofluorescence staining or Western blotting. The results showed that when S. Typhimurium was co-incubated with S-layer proteins, the S. Typhimurium-induced Caco-2 cell F-actin rearrangement was reduced, and the S. Typhimurium-induced TER decrease and interleukin 8 (IL-8) secretion were attenuated. Additionally, L. acidophilus S-layer proteins could inhibit S. Typhimurium-induced phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Jun amino-terminal kinase (JNK) and p38. This study indicates that L. acidophilus S-layer proteins are able to inhibit S. Typhimurium infection through blocking S. Typhimurium-induced F-actin rearrangements and S. Typhimurium-induced ERK1/2, JNK and p38 activation in Caco-2 cells. These data provide a rationale for the use of lactobacillus S-layer proteins as therapeutic and preventative agents, at least in infectious diarrhoea.
authors.affiliation: College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China.
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Li
authors.affiliation: College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China.
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Yu
authors.affiliation: College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China.
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Ye
authors.affiliation: College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China.
authors.forename: Zhisheng
authors.initials: Z
authors.lastname: Wang
authors.affiliation: College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Yang
mesh_terms: D008841:Actin Cytoskeleton / Q000648:ultrastructure*; D000199:Actins / Q000378:metabolism; D001422:Bacterial Adhesion / Q000187:drug effects; D018938:Caco-2 Cells; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D007778:Lactobacillus / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008562:Membrane Glycoproteins / Q000378:metabolism* / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012475:Salmonella / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000199:Actins; D016209:Interleukin-8; D008562:Membrane Glycoproteins; C055764:S-layer proteins; D020928:Mitogen-Activated Protein Kinases