Functional and genomic characterization of immunobiotic lactobacilli for immunosynbiotic development

ZHOU, BINGHUI; INDO, YUHKI; ALBARRACIN, LEONARDO; MASUMIZU, YUKI; ISLAM, MD AMINUL; IKEDA-OHTSUBO, WAKAKO; ASO, HISASHI; VILLENA, JULIO; KITAZAWA, HARUKI

Conferencia; The 11th Asian Conference for Lactic Acid Bacteria; 2021

Immunobiotics were identified as those probiotic bacteria that promote health through the beneficial modulation of the mucosal immune system (Clancy R., FEMS Immunology & Medical Microbiology, 2003). In our previous study, the term “immunosynbiotics” was proposed to describe the combination of immunoregulatory probiotics and prebiotics with synergistic effects (Masumizu Y. et al., Microorganisms, 2019). The seaweed wakame (Undaria pinnatifida) has been proposed as an immunoprebiotic because of its biologically active components that could modulate the immune system function, including anti-inflammatory and antiviral activities (Liu, F. et al., Phytomedicine, 2012).This study aimed to select and characterize potentially beneficial lactobacilli strains isolated from the intestine of wakame-fed pigs by evaluating their interaction with porcine epithelial (PIE) cells in terms of their ability to regulate TLR3- or TLR4-mediated innate immune responses, as well as their abilities of wakame assimilation. These functional studies were complemented with a comparative genomic evaluation using the complete genome sequences of lactobacilli that demonstrated interesting immunobiotic properties.One-hundred and sixteen Ligilactobacillus salivarius strains isolated from the jejunum, ileum, or ileum Peyer’s patches of wakame-fed pigs were evaluated according to their ability to modulate the response of PIE cells to the challenges with TLR3 or TLR4 ligands. The expression changes of IFN-, Mx1, IL-8, and MCP-1 clearly showed the strain-dependent capacities of L. salivarius strains in modulating the innate immune responses in the epithelial cells of porcine origin. Eight strains were selected due to their differential immunomodulatory abilities for further studies. The comparative genomic studies strongly suggested that the cell wall and the surface molecules expressed in different L. salivarius strains are involved in their interaction with the host´s cells. Using wakame-based broths developed in this study containing enzyme-treated wakame leaf or wakame stalk, lactobacilli able to grow in these substrates were selected. Although all lactobacilli were isolated from wakame-fed pigs, not all of them had the ability to efficiently growth on those culture media. The comparative genomic analysis revealed that the differences between the strains are not due only to the different genes present in each genome but in addition due to differences in their expression. The results of this work indicate that selected lactobacilli with the ability to grow in wakame and with remarkable immunomodulatory activities could be efficiently used for the development of immunosynbiotics products.