DNA methylation profile and expression of the phyllagrin gene in patients with atopic dermatitis: case-control study

Abstract

Background. Atopic dermatitis (AD) is one of the most common inflammatory skin diseases, affecting up to 20.0% of children and 2.0–8.0% of adults worldwide. Patients with atopic dermatitis usually have dry skin and itching, they are at higher risk of developing asthma, as well as allergic rhinitis. Features of the clinical course of AD are associated with both interaction of genes and influence of environmental factors. Studying epigenetic mechanisms could provide understanding of the most likely mechanisms by which environmental factors influence gene expression and contribute to the development of AD. The aim of the study is to conduct a comprehensive molecular genetic analysis (assessment of the level of global DNA methylation and expression of the filaggrin gene (FLG) in patients with moderate to severe AD. Material and methods: The case-control study was conducted from January 2022, through June 2022. A total of 32 patients with AD and 6 healthy volunteers were recruited. The level of global DNA methylation in the blood of patients with AD and healthy individuals was assessed. The FLG expression was measured by polymerase chain reaction in the leukocyte fraction of blood. A three-stage cycle is used during PCR. To determine the expression level of the FLG gene, total RNA was isolated, followed by a reverse transcription, amplification, and detection reaction. Results. A hypermethylation of the genome in patients with AD is 2.3 times higher than the methylation of genome in controls (p = 0.003),it was also found that the expression level of the FLG gene (exon 3, position 7–8, and exon 1) in the leukocyte fraction of blood in patients with AD did not significantly differ from the control group (p = 0.41). Conclusion. The current study found that the epigenome of AD patients differs from healthy individuals. The study of pathogenetic mechanisms is the basis for the development of new methods of targeted therapy for this socially significant dermatosis.