Forkhead Box P3 Methylation and Expression in Men with Obstructive Sleep Apnea.

David Sanz-Rubio,Marta Forner,Luis Varona,Pablo Cubero,Arianne Sanz,Jose M Marin,Inmaculada Martin-Burriel,Rosa Bolea,Marta Marin-Oto,Ana V Gil

doi:10.3390/ijms21062233

Abstract

Background: Epigenetic changes in obstructive sleep apnea (OSA) have been proposed as a mechanism for end-organ vulnerability. In children with OSA, Forkhead Box P3 (FOXP3) DNA methylation were associated with inflammatory biomarkers; however, the methylation pattern and its effect in the expression of this gene have not been tested in adults with OSA. Methods: Plasma samples from subjects without comorbid conditions other than OSA were analyzed (the Epigenetics Status and Subclinical Atherosclerosis in Obstructive Sleep Apnea (EPIOSA) Study: NCT02131610). In 16 patients with severe OSA (Apnea-Hypopnea Index—AHI- > 30 events/h) and seven matched controls (AHI < 5), methylation of FOXP3 gen was evaluated by PCR of the promoter and by pyrosequencing of the intron 1 Treg-specific demethylated region (TSDR). In another 74 patients with OSA (AHI > 10) and 31 controls, we quantified FOXP3 protein expression by ELISA and gene expression by quantitative real-time PCR. C-reactive protein (CRP) and plasma Treg cells were also evaluated. Results: Neither the levels of the promoter nor the TSDR demethylated region were different between controls and patients with OSA, whether they were grouped by normal or high CRP. FOXP3 protein and mRNA expression did not differ between groups. Conclusions: FOXP3 methylation or its expression is not altered in adults with OSA, whatever their inflammatory status.

Highlights

Obstructive sleep apnea (OSA) is a very prevalent sleep disorder characterized by recurrent episodes of partial or complete pharyngeal obstruction [1]
Interleukin-6 (IL-6) and C-reactive protein (CRP) are key inflammatory biomarkers associated with an increased risk of atherosclerosis and cardiovascular disease [5]
Hypermethylation of the Forkhead Box P3 (FOXP3) gene occurs in children suffering obstructive sleep apnea (OSA) and systemic inflammation [9], and it was suggested that this epigenetic modification could lead to a downregulation of FOXP3 and the subsequent reduction of the number of Treg cells

Summary

Introduction

Obstructive sleep apnea (OSA) is a very prevalent sleep disorder characterized by recurrent episodes of partial or complete pharyngeal obstruction [1]. Systemic inflammatory variability responses in patients with OSA could be explained by different patterns of epigenetic modifications induced by the apneic episodes and, by the altered expression of genes involved in the atherosclerotic process. A prominent characteristic of OSA, can induce hypermethylation of genes involved in cardiovascular diseases [6,7] One of these genes, Forkhead Box P3 (FOXP3), controls the differentiation of lymphocytes into regulatory T lymphocytes (Treg), a subset of T helper cells that inhibit atherosclerosis by modulating lipoprotein metabolism [8]. In 16 patients with severe OSA (Apnea-Hypopnea Index—AHI- > 30 events/h) and seven matched controls (AHI < 5), methylation of FOXP3 gen was evaluated by PCR of the promoter and by pyrosequencing of the intron 1 Treg-specific demethylated region (TSDR). Conclusions: FOXP3 methylation or its expression is not altered in adults with OSA, whatever their inflammatory status

Methods

Results

Discussion

Conclusion