Objective:To evaluate the effect of Lactobacillus-derived extracellular vesicles (Lac-EVs) on lipopolysaccharide (LPS)-induced activation of microglia and proteomic analysis.Methods:BV2 microglia obtained from mice with good growth status were divided into 3 groups ( n=12 each) using a random number table method: control group (group C), LPS group (group L) and LPS+ Lac-EVs group (group L+ E). Group C was commonly cultured. Group L was incubated for 24 h with LPS (final concentration 1 μg/ml). Group L+ E was incubated for 24 h with Lac-EVs (final concentration 2.5 μg/ml) after being treated with LPS for 24 h. The expression of CD86 and CD206 was detected using immunofluorescence staining. Cell precipitates were taken from L and L+ E groups, and proteomics were used to screen for differentially expressed proteins between the two groups. The differentially expressed proteins were analyzed by the bioinformatics analysis, and two differentially expressed proteins, apolipoprotein A1 and G protein-coupled receptor kinase 2, were verified by quantitative real-time polymerase chain reaction and Western blot. Results:Compared with group C, the expression of CD86 was significantly up-regulated, and the expression of CD206 was down-regulated in group L ( P<0.05). Compared with group L, the expression of CD86 was significantly down-regulated, and the expression of CD206 was up-regulated in L+ E group ( P<0.05). One hundred and twenty-five differentially expressed proteins were identified using proteomics (FC=2.0, P<0.05), of which the expression of 66 proteins was up-regulated and the expression of 59 proteins was down-regulated. The results of GO analysis indicated that these differentially expressed proteins were mainly involved in biological processes such as endothelial cell proliferation, SDNA damage detection, and lipoprotein transport. The results of KEGG analysis indicated that there were differences in PPAR signaling pathway, endocytosis, metabolic pathway, MAPK signaling pathway, etc. The expression trends of the differentially expressed proteins determined by Western blot and quantitative real-time polymerase chain reaction were consistent with the results of proteomics. Conclusions:Lac-EVs can inhibit LPS-induced microglial polarization toward M1 phenotype, and the mechanism may be related to the up-regulated differential proteins apolipoprotein A1 and G protein-coupled receptor kinase 2.

Laboratory-based pathogen isolation, identification, and toxicity determination were performed on samples from a suspected case of infant botulism. Mice injected with cultures generated from the enema sample and ingested Powered infant formula (PIF) presented typical signs of botulism. Antitoxins to polyvalent botulinum neurotoxins (BoNTs) and monovalent BoNT type B antitoxin had protective effects. Clostridium botulinum isolated from the enema and residual PIF samples were positive for type B toxin. Pulsed-field gel electrophoresis (PFGE) revealed that the two strains of C. botulinum isolated from the two samples produced indistinguishable pulsotypes. These findings confirmed this case of type B infant botulism associated with the ingestion of PIF contaminated by type B C. botulinum spores.
Animals ; Beijing ; epidemiology ; Botulinum Toxins ; isolation & purification ; toxicity ; Botulism ; diagnosis ; epidemiology ; Clostridium botulinum ; isolation & purification ; Gastrointestinal Tract ; microbiology ; Humans ; Infant ; Mice ; Toxicity Tests