Epigenetics in Food Allergy and Immunomodulation

Abstract

Food allergy (FA) is an increasing problem worldwide and, over recent years, its prevalence is rising in developed countries. Nowadays, the immunological and cellular processes that occur in the allergic reactions are not fully understood, which hampers the development of in vitro diagnostic tools and further treatment options. Moreover, allergic diseases could be reinforced by environmental exposure and genetic modifications. Gene expression can be controlled by different epigenetic mechanisms like DNA methylation, histone modifications, and microRNAs. In addition, several environmental factors such as dietary components (vitamin D, butyrate, folic acid) are able to regulate this epigenetic mechanism. All these factors produce modifications in immune genes that could alter the development and function of immune cells, and therefore the etiology of the disease. Furthermore, these epigenetic mechanisms have also an influence on immunomodulation, which could explain sustained responsiveness or unresponsiveness during immunotherapy due to epigenetic modifications in key genes that induce tolerance in several FA. Thus, in this review we focus on the different epigenetic mechanisms that occur in FA and on the influence of several dietary components in these gene modifications.

Keywords: DNA modification; environmental factors; epigenetic mechanisms; food allergy.

Figure 1

Gene expression regulation can be exerted by three different epigenetic mechanisms: histone modifications, DNA methylation, and miRNAs. DNA methylation involves the addition of a methyl group to a cytosine in CpG dinucleotide sequences (CG), and CG rich regions are known as CpG islands. Histones can be modified by ubiquitination, phosphorylation acetylation, and methylation, producing DNA packing. miRNAs are non-coding RNAs that bind to mRNA and block protein translation. RISC, RNA-Induced Silencing Complex.