title: Lactobacillus rhamnosus GR-1 Ameliorates Escherichia coli-Induced Inflammation and Cell Damage via Attenuation of ASC-Independent NLRP3 Inflammasome Activation.
abstract: Escherichia coli is a major environmental pathogen causing bovine mastitis, which leads to mammary tissue damage and cell death. We explored the effects of the probiotic Lactobacillus rhamnosus GR-1 on ameliorating E. coli-induced inflammation and cell damage in primary bovine mammary epithelial cells (BMECs). Increased Toll-like receptor 4 (TLR4), NOD1, and NOD2 mRNA expression was observed following E. coli challenge, but this increase was attenuated by L. rhamnosus GR-1 pretreatment. Immunofluorescence and Western blot analyses revealed that L. rhamnosus GR-1 pretreatment decreased the E. coli-induced increases in the expression of the NOD-like receptor family member pyrin domain-containing protein 3 (NLRP3) and the serine protease caspase 1. However, expression of the adaptor protein apoptosis-associated speck-like protein (ASC, encoded by the Pycard gene) was decreased during E. coli infection, even with L. rhamnosus GR-1 pretreatment. Pretreatment with L. rhamnosus GR-1 counteracted the E. coli-induced increases in interleukin-1β (IL-1β), -6, -8, and -18 and tumor necrosis factor alpha mRNA expression but upregulated IL-10 mRNA expression. Our data indicate that L. rhamnosus GR-1 reduces the adhesion of E. coli to BMECs, subsequently ameliorating E. coli-induced disruption of cellular morphology and ultrastructure and limiting detrimental inflammatory responses, partly via promoting TLR2 and NOD1 synergism and attenuating ASC-independent NLRP3 inflammasome activation. Although the residual pathogenic activity of L. rhamnosus, the dosage regimen, and the means of probiotic supplementation in cattle remain undefined, our data enhance our understanding of the mechanism of action of this candidate probiotic, allowing for development of specific probiotic-based therapies and strategies for preventing pathogenic infection of the bovine mammary gland.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, China Agricultural University, Beijing, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, China Agricultural University, Beijing, China.
authors.forename: Ming-Chao
authors.initials: MC
authors.lastname: Liu
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, China Agricultural University, Beijing, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, China Agricultural University, Beijing, China.
authors.forename: Jiu-Feng
authors.initials: JF
authors.lastname: Wang
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, China Agricultural University, Beijing, China zhu_yaohong@hotmail.com.
authors.forename: Yao-Hong
authors.initials: YH
authors.lastname: Zhu
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D004847:Epithelial Cells / Q000276:immunology* / Q000382:microbiology*; D004927:Escherichia coli Infections / Q000473:pathology / Q000662:veterinary*; D005455:Fluorescent Antibody Technique; D020869:Gene Expression Profiling; D058847:Inflammasomes / Q000378:metabolism*; D007249:Inflammation / Q000473:pathology*; D052201:Lacticaseibacillus rhamnosus / Q000276:immunology*; D008954:Models, Biological; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D019936:Probiotics / Q000494:pharmacology
chemical_list: D002352:Carrier Proteins; D016207:Cytokines; D058847:Inflammasomes; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C453881:NLRP3 protein, human