Characterization of Inflammasome Components in Pig Intestine and Analysis of the Influence of Probiotic Enterococcus Faecium during an Escherichia Coli Challenge

Abstract

The aim of the present study was to investigate systematically the expression of inflammasome components in pig intestine and to analyze the influence of age and long-term supplementation with the probiotic Enterococcus faecium NCIMB 10415 (E. faecium). In order to examine probiotic effects on the inflammasomes during a challenge with pathogens, enterotoxigenic Escherichia coli (ETEC) and E. faecium were directly added to pig jejunum in Ussing chambers. The mRNA expression of inflammasome components generally decreased in an oral-aboral direction in intestinal tissues. In 29-day-old piglets, the expression levels of NLRP3 were significantly higher and ASC (apoptotic speck-like protein containing a caspase recruitment domain) expression were lower compared with those in the ileum of 70-day-old pigs (p ≤ 0.05). Long-term supplementation with E. faecium significantly increased ASC expression levels in the jejunum and ileum of 29-day-old piglets compared to control animals (p ≤ 0.05). Ex vivo addition of ETEC or E. faecium did not affect mRNA expression of inflammasome components significantly, whereas IL-1β protein release was significantly elevated in ETEC-incubated jejunum (p ≤ 0.05), providing evidence for the functional activation of the inflammasome, which was prevented by pre-incubation with E. faecium. We conclude that pre-incubation with E. faecium has a protective effect during ETEC challenge; this effect is probably not located at the inflammasome transcription level. The results of this study of the expression and regulation of inflammasome components in pigs are similar to those obtained in humans, reinforcing the use of pigs as a suitable model for translational inflammasome research.

Longitudinal microbiome profiling reveals impermanence of probiotic bacteria in domestic pigeons

“…E . faecium is often used in mixed probiotic supplements in humans and livestock with positive effects [53,54], but the mechanisms underlying the benefits to its hosts are not as well known. It is possible that the plant-based diet of pigeons could provide better substrates for Lactobacillus spp.…”

Inflammasomes in livestock and wildlife: Insights into the intersection of pathogens and natural host species

“…The diabetes drug glyburide was the first small-molecule drug demonstrated to inhibit the NLRP3 inflammasome (Lamkanfi et al, 2009), and this therapeutic was followed by identification of numerous other small-molecule inflammasome inhibitors (reviewed by Guo et al, 2015), including NLRP3 inhibitors CY-09 (Jiang et al, 2017) and MCC950 (Coll et al, 2015), and caspase-1 inhibitors (e.g., Wannamaker et al, 2007; Juliana et al, 2010; MacKenzie et al, 2010). Probiotic bacteria serve as another potential veterinary intervention with promise for future research; a new study in pigs examined the impact of an Enterococcus faecium probiotic on transcription of NLRP3 inflammasome components and IL-1β secretion in jejunum sections after Gram-negative pathogen challenge, with a reduction of IL-1β secretion observed with probiotic pre-incubation (Kern et al, 2017). In the swine industry, minimizing gut inflammation through feed supplementation may be of particular interest for growth promotion.…”

Interplays between inflammasomes and viruses, bacteria (pathogenic and probiotic), yeasts and parasites

“…Probiotic bacteria have no impact on inflammasome activation and pro-inflammatory cytokine synthesis in healthy individuals, but probiotics may regulate inflammasome activation in organisms that have previously experienced some degree of inflammation due to pathogenic bacterial infection [ 64 , 65 ].…”

“…E. faecium and E. faecalis colonize the human intestine in the first days of life and are part of the healthy gut microflora of humans and animals. E. faecium has gained particular importance thanks to beneficial strains marketed as probiotics [ 65 ]. This addition of probiotic E. faecium NCIMB 10415 to the diet of healthy pigs did not affect mRNA expression of NLRP6, NLRP3, caspase-1, IL-1β, and IL-18, but it increased the ASC expression level in the jejunum and ileum in comparison to the control group.…”

“…This addition of probiotic E. faecium NCIMB 10415 to the diet of healthy pigs did not affect mRNA expression of NLRP6, NLRP3, caspase-1, IL-1β, and IL-18, but it increased the ASC expression level in the jejunum and ileum in comparison to the control group. In contrast, in an ex vivo experiment using chambers (an apparatus for measuring epithelial membrane properties), pre-incubation of porcine jejunum with the probiotic E. faecium led to an increase in IL-1β release during incubation with enterotoxigenic E. coli (ETEC), but it did not affect the mRNA expression of inflammasome components [ 65 ]. Additionally, preincubation of porcine monocyte-derived DC (MoDC) cells with E. faecium NCIMB 10415 did not influence NLRP3, NLRP6 and NLRC4 inflammasome activation in comparison to cells infected with ETEC alone [ 66 ].…”