Cellular and molecular pathways through which commensal bacteria modulate sensitization to dietary antigens

Abstract

Food allergies are a growing public health concern. The rapidly increasing prevalence of allergic disease cannot be explained by genetic variation alone, suggesting a role for gene-by-environment interactions. The bacteria that colonize barrier surfaces, often referred to as the commensal microbiota, are dramatically affected by environmental factors and have a major impact on host health and homeostasis. Increasing evidence suggests that alterations in the composition of the microbiota, caused by factors such as antibiotic use and diet, are contributing to increased sensitization to dietary antigens. This review will discuss the cellular and molecular pathways activated by commensal bacteria to protect against allergic sensitization. By understanding the interplay between the environment, the microbiota, and the host, we may uncover novel therapeutic targets that will allow us to control the allergy epidemic.

Eosinophilic esophagitis: published evidences for disease subtypes, indications for patient subpopulations, and how to translate patient observations to murine experimental models

“…One perfect example for the problem of doing functional studies that define cause and effect in EoE pathology are studies on the role of the microbial signals for EoE development. Such studies are highly important in view of the recent description of the EoE specific microbiome [ 90 ] and the rapidly growing knowledge of the role of microbial signals in allergies of the GI tract [ 91 , 92 ]. Germ-free humans do not exist and, even in mice, microbiome studies are challenging and highly costly.…”

Microbially competent 3D skin: a test system that reveals insight into host–microbe interactions and their potential toxicological impact

“…Amongst the skin's Micrococcaceae M. luteus is the predominant species (Chiller et al 2001). It is considered essential for the population balance of the skin's microbiome (Epstein 2015) and usually accounts for 20-80% of the micrococci isolated (Davis 1996). Correspondingly P. oleovorans belongs to the Proteobacteria which make up to 34% of the whole skin microbiome (Kim et al 2018).…”

“…Likewise, skin commensals have been shown to induce and control T cell responses in mouse models (Linehan et al 2018 ; Schommer and Gallo 2013 ). Effects observed include increased production of pro-inflammatory molecules such as interferon-γ (INFγ) and interleukin (IL)-17A with the regulatory factors involved [IL-1α, IL-1β, IL-6, Transforming Growth Factor (TGF)-β] being partly induced or regulated by skin commensals (Feehley and Nagler 2014 ; Hasegawa et al 2012 ; Naik et al 2012 ; Veldhoen et al 2008 ). These cytokines are also essential for the expression of various AMPs (Huang et al 2002 ; Steinz et al 2014 ).…”

The microbiome and its impact on food allergy and atopic dermatitis in children

“…The gut microbiome serves many functions to the host, but in allergy, the influence of the gut microbiome on the immune system is of key importance [ 21 , 58 ]. It is thought that the most important function of the microbiome is its influence on the development and function of the immune system, maintaining the balance between the Th1/Th2 response, by regulating various lymphocyte subpopulations, especially Tregs, responsible for immune tolerance [ 11 , 17 , 21 , 58 – 60 ]. In the absence of an intact intestinal microbiome, the levels of both IgE and circulating basophils are increased [ 61 ].…”