Molecules Produced by Probiotics and Intestinal Microorganisms with Immunomodulatory Activity

Abstract

Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. The probiotic microorganisms most commonly used in the food and pharmacy industry belong to Lactobacillus and Bifidobacterium, and several strains of these genera have demonstrated beneficial attributes. In addition, some other intestinal bacteria inhabiting the human microbiota, such as Faecalibacterium prausnitzii and Akkermansia muciniphila, have recently been discovered and are able to display health-promoting effects in animal and human trials. The beneficial properties of probiotics have been known for a long time, although little is known about the molecular mechanisms and the molecules responsible for their effects. However, in recent years, advances in microbiome studies, and the use of novel analytical and molecular techniques have allowed a deeper insight into their effects at the molecular level. This review summarizes the current knowledge of some of the molecules of probiotics and other intestinal commensal bacteria responsible for their immunomodulatory effect, focusing on those with more solid scientific evidence.

FN3 protein fragment containing two type III fibronectin domains from B. longum GT15 binds to human tumor necrosis factor alpha in vitro

“…The effect of the gut microbiota on the development and maintenance of homeostasis of the immune status in humans could not be overestimated. Probiotic bacteria (probiotics) such as bifidobacteria, are a major component of the gut microbiota, which selectively regulate the expression of pro-inflammatory and anti-inflammatory cytokines [ 40 , 41 ].…”

“…The PFNA operon including the gene fn3 is potentially a unique feature of bifidobacteria. Studying the PFNA operon can enhance our conceptions [ 41 , 45 ] regarding the interaction of bifidobacteria with the host organism.…”

Probiotics (Direct-Fed Microbials) in Poultry Nutrition and Their Effects on Nutrient Utilization, Growth and Laying Performance, and Gut Health: A Systematic Review

“…When SCFA is produced through the microbial fermentation of carbohydrate in the intestine, the SCFA metabolites act on leukocytes and endothelial cells through activating G-protein-coupled receptors (GPCRs) and inhibit histone deacetylase. Besides the interaction with various receptors, SCFAs promote the generation of IgA by B-immune cells, inhibit the NF-κB transcription factor, and reduce chemokine and cytokine production [ 64 ]. Another study [ 65 ] compared the effects of feeding a mixture of DFM and a multienzyme combination (xylanase, amylase, and protease) as AGP in the feed with the same multienzyme combination alone.…”

Gastrointestinal Disorders and Metabolic Syndrome: Dysbiosis as a Key Link and Common Bioactive Dietary Components Useful for their Treatment

“…Probiotics usually include species of Lactobacillus , Bifidobacterium , or Saccharomyces genera, some Gram-positive cocci and some strains of Escherichia coli . They can be consumed in powdered, gel, paste, or granule forms, in liquid form and in capsule forms, have non-pathogenic and non-toxic properties, and are able to adhere to gut epithelial tissues and produce SCFAs [ 96 , 97 , 98 ]. Probiotics can provide a number of benefits to the host beyond nutrition, such as enhancing intestinal epithelial integrity, regulating immunity of the GI mucosa, protecting gut barrier disruption, and inhibiting the growth and/or activity of pathogenic microbes in the GI [ 70 , 71 , 99 ].…”