Beneficial effect of immunobiotic strains on attenuation of Salmonella induced inflammatory response in human intestinal epithelial cells

Abstract

Probiotic bacteria have the ability to modulate host immune responses and have potent therapeutic functional effects against several diseases, including inflammatory diseases. However, beneficial effects of probiotics are strain specific and their interactions with host immune cells to modulate inflammatory response are largely unknown. Intestinal epithelial cells (IECs), which are the first line of defense against invading pathogens, and connects between commensals/probiotics and immune system; therefore, in this study, we used human IECs to assess the probiotic effects of three selected Lactobacillus strains in vitro. An HT-29 colonic epithelial cell and HT-29/blood mononuclear cells co-culture system were stimulated with Lactobacillus followed by Salmonella for different hours, after which the mRNA level of cytokines, β-defensin-2 and negative regulators for TLR signaling and protein levels of ZO-1 and IκB-α were analyzed by real-time polymerase chain reaction and western blot analysis. L. brevis decreased Salmonella induced IL-6, IL-8, MCP-1 and IL-1β levels, whereas L. pentosus suppressed IL-6 and MCP-1 in HT-29 cells. Moreover, L. brevis was able to increase the mRNA levels of A20, Tollip, SIGIRR and IRAKM, while L. pentosus reduced the levels of A20, and IRAKM in response to Salmonella. In addition, decrease in protein level of TNF-α and increase in mRNA level of IL-10 was observed in L. brevis and L. pentosus treated HT-29 cells. Lactobacillus strains were differentially modulated ZO-1 and p-IκB-α in HT-29 cells treated with Salmonella. Overall, the results of this study indicate that Lactobacillus strains attenuate Salmonella induced inflammatory responses through beneficial modulation of TLR negative regulators and the NF-κB pathway.

Anti-inflammatory Effect of Probiotic Limosilactobacillus reuteri KUB-AC5 Against Salmonella Infection in a Mouse Colitis Model

“…Several strains of Limosilactobacillus reduced Salmonella lipopolysaccharide (LPS)-induced gut epithelial barrier impairment by increasing tight junction protein expressions ( Fang et al, 2010 ; Yeung et al, 2013 ). Limosilactobacillus probiotics attenuated Salmonella -induced gut inflammation by reducing pro-inflammatory cytokine production by the attenuation of TLRs activation in vitro ( Kanmani and Kim, 2020 ). Kanmani and Kim (2020) showed that Limosilactobacillus isolated from Korean food increased production of the immunosuppressive cytokine IL-10, transforming growth factor (TGF)-β, and antimicrobial peptide β-defensin by manipulating the expression of TLR negative regulators in human colonocytes.…”

“…Limosilactobacillus probiotics attenuated Salmonellainduced gut inflammation by reducing pro-inflammatory cytokine production by the attenuation of TLRs activation in vitro (Kanmani and Kim, 2020). Kanmani and Kim (2020) showed that Limosilactobacillus isolated from Korean food increased production of the immunosuppressive cytokine IL-10, transforming growth factor (TGF)-β, and antimicrobial peptide β-defensin by manipulating the expression of TLR negative regulators in human colonocytes. Liu et al (2019) demonstrated anti-Salmonella activity of Limosilactobacillus in mice.…”

Benefits of Probiotics in Rheumatic Diseases

“…The modulation of TLR signaling might represent an additional mechanism through which probiotics exert their effects in rheumatic diseases. Besides their ability in binding specific TLRs and affect downstream signaling, it has been shown that some lactobacillus strains can promote the expression of proteins which negatively regulate TLR activity, thus attenuating the inflammatory response induced by different pathogens (41).…”

Probiotic Bacteria and Their Cell Walls Induce Th1-Type Immunity Against Salmonella Typhimurium Challenge

“…Probiotics can activate the gut immune system by direct interaction with the intestinal epithelial and immune cells and modulate lamina propria and extraintestinal immune cell functions (8)(9)(10). In addition, one of the most extensively effects documented for certain probiotic strains are their capacity to exclude or inhibit enteric pathogens such as Salmonella (11)(12)(13)(14)(15).…”