Study On The Immune Mechanism Of Lactobacillus Acidophilus CICC6074 SlpA Mediated By TLR4 Signaling Pathway

Lactobacillus acidophilus is an important member of Lactobacillus It is confirmed that it plays an important role in enhancing the body's immunity.Among them,the immune effect is mainly located in the cell wall peptidoglycan,lipoteichoic acid,and S-layer proteins.Lactobacillus acidophilus is encoded by two kinds of genes,SlpA and SlpB,but SIpB is generally not expressed due to the silencing mechanism of SlpB.Previous studies have shown that different concentrations of SlpA can promote the release of inflammatory cytokines in mouse peritoneal macrophages RAW264.7 to varying degrees.Such as tumor necrosis factor-?(TNF-?),interleukin-10(IL-10),interleukin-1?(IL-1?)etc..However,there are few reports on the immune mechanism of SlpA.Therefore,based on previous studies,this study extracted SlpA from Lactobacillus acidophilus CICC6074 to study the mechanism of SlpA exerting immune response.1?The RAW264.7 inflammation model of mouse peritoneal macrophages was established using lipopolysaccharide(LPS)as an inducer,and real-time fluorescence quantitative PCR(qRT-PCR)and enzyme-linked immunosorbent assay(ELISA)were used to detect TNF-?,IL-10,IL-1?,IFN-?,IFN-? expression quantity.2?Western blotting and immunofluorescence methods were used to detect the expression of related inflammatory proteins and receptors in different signaling pathways,and to observe the nuclear expression of related transcription factors.Experimental results show:SlpA can inhibit overexpression of membrane-receptor proteins TLR4,cytoplasmic receptors NLRP3,NOD2 and other inflammation-related receptors,and further modulate downstream phosphorylation of relevant proteins in the downstream signaling pathways such as NF-kB,MAPK,and TRIF,and incorporation of transcription factors(p65,p50,AP-1,pIRF3,and pIRF7)into the nucleus and binding to target genes.3?The mouse was used as the research subject and the inflammation model was established.Combined with the previous research,the regulation mechanism of Lactobacillus acidophilus CICC6074 SlpA on intracellular signaling pathways was used to further study the anti-inflammatory effects and immune response mechanisms of SlpA at the animal level.The experimental results show that SlpA can inhibit the over-expression of receptor TLR4 induced by DSS,thereby inhibiting the release of related inflammatory cytokines(IL-10,INOS,COX-2,etc.)in serum,and effectively reducing the body weight in mice.The disease index,and an effective therapeutic effect on inflammation of the mouse colon tissue caused by inflammation.4?Isotopic relative labeling and absolute quantitation(iTRAQ)technology was also used to perform proteomic analysis on SlpA-acting macrophages,and used bioinformatics methods to analyze the statistically significant differential proteins that were combined with the KEGG pathway.Through the enrichment situation to find potential relevant signaling pathways in the process of SlpA exert immune effects.