Lactobacillus plantarum BC299 can alleviate dextran sulphate sodium‐induced colitis by regulating immune response and modulating gut microbiota

Evaluation of the immunogenicity of auxotrophic Lactobacillus with CRISPR-Cas9D10A system-mediated chromosomal editing to express porcine rotavirus capsid protein VP4

Porcine rotavirus (PoRV) is an important pathogen, leading to the occurrence of viral diarrhoea . As the infection displays obvious enterotropism, intestinal mucosal immunity is the significant line of defence against pathogen invasion. Moreover, as lactic acid bacteria (LAB) show acid resistance, bile salt resistance and immune regulation, it is of great significance to develop an oral vaccine. Most traditional plasmid delivery vectors use antibiotic genes as selective markers, easily leading to antibiotic accumulation. Therefore, to select a food-grade marker in genetically engineering food-grade microorganisms is vital. Based on the CRISPR-Cas9D10A system, we constructed a stable auxotrophic Lactobacillus paracasei HLJ-27 (Lactobacillus △Alr HLJ-27) strain. In addition, as many plasmids replicate in the host bacteria, resulting in internal gene deletions. In this study,we used a temperature-sensitive gene editing plasmidto insert the VP4 gene into the genome, yielding the insertion mutant strains VP4/△Alr HLJ-27, VP4/△Alr W56, and VP4/W56. This recombinant bacterium efficiently induced secretory immunoglobulin A (SIgA)-based mucosal and immunoglobulin G (IgG)-based humoral immune responses. These oral mucosal vaccines have the potential to act as an alternative to the application of antibiotics in the future and induce efficient immune responses against PEDV infection.

Modulation of the gut microbiota and glycometabolism by a probiotic to alleviate amyloid accumulation and cognitive impairments in AD rats

SCOPE

Regulating the gut microecology by probiotics is an efficient strategy to rational prevention and treatment of Alzheimer's disease (AD). However, there is currently a lack of well-known probiotic species in the protection against AD, and the involved mechanism has not been clearly interpreted.

METHODS AND RESULTS

Herein, Lactobacillus plantarum MA2 (MA2), a functional probiotic isolated from traditional Chinese Tibetan kefir grains, was demonstrated to improve the cognitive deficits and anxiety-like behaviors in the D-galactose/AlCl₃ induced AD rats, and attenuate the neuronal degeneration and Aβ accumulation in the brain. Moreover, we found MA2 could alleviate the intestinal mucosal impairments, and impede the activation of microglia and neuroinflammation through TLR4/MYD88/NLRP3 signaling pathway. 16S rRNA sequencing and metabolomic analysis indicated that MA2 reshaped the gut microbiota structure and composition, and remarkably modulated the glycometabolism. In that case, the EPS (exopolysaccharides) that derived from MA2 was furtherly proved with inhibitory effects on the Aβ42 aggregation and amyloid-induced cytotoxicity.

CONCLUSION

MA2 or MA2 EPS may be used as functional food and nutritional supplement for regulating the gut microbiota and metabolism disorders in AD. This study is of great significance to develop new intervention and therapeutic strategy on AD using probiotics and their metabolites. This article is protected by copyright. All rights reserved.

Lactobacillus kefiranofaciens ZW18 from Kefir enhances the anti-tumor effect of anti-programmed cell death 1 (PD-1) immunotherapy by modulating gut microbiota

The research of probiotics assisting PD-1 inhibitors in anti-tumor has attracted widespread attention. Therefore, it is significative to find new probiotic strains with PD-1 inhibitors promoting effect. This study aims...