Isabelle Rivals, Anne Bergougnoux, Mélodie Thomasset, Mireille Claustres, Sylvie Leroy, Davide Caimmi, Emmanuelle Beyne, M. Murris, Raphaël Chiron, Isabelle Vachier, Laurent Mely, Harriet Corvol, Jessica Varilh, Albertina De Sario, Milena Magalhães, Loïc Guillot, Laboratoire de génétique des maladies rares. Pathologie moleculaire, etudes fonctionnelles et banque de données génétiques (LGMR), Université Montpellier 1 (UM1)-IFR3, Université Montpellier 1 (UM1)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Montpellier (UM), Equipe de Statistique Appliquée (UMRS 1158) (ESA), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Neurophysiologie Respiratoire Expérimentale et Clinique, Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU), Centre de Ressources et de Compétences en Mucoviscidose [Lyon] (CRCM [Lyon]), Hospices Civils de Lyon (HCL)-CHU Lyon-Hôpital Renée Sabran [CHU - HCL], Hospices Civils de Lyon (HCL), Centre de Ressources et de Compétences en Mucoviscidose [Nice] (CRCM [Nice]), Les Hôpitaux Pédiatriques de Nice CHU-Lenval, Hôpital Trousseau, Centre Hospitalier Régional Universitaire de Tours (CHRU Tours), Centre de Recherche Saint-Antoine (UMRS893), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre de Ressources et de Compétences en Mucoviscidose [Toulouse] (CRCM [Toulouse]), CHU Toulouse [Toulouse]-Hôpital Larrey [Toulouse], CHU Toulouse [Toulouse], Centres de Ressources et de Compétences de la Mucoviscidose [Montpellier] (CRCM [Montpellier]), Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Hôpital Arnaud de Villeneuve-Service des Maladies Respiratoires, The project was funded by VLM, INSERM, and Montpellier Hospital. MM was supported by the Ciência Sem Fronteiras Program (CNPq, Brazil) and EB by CHU Montpellier. The FrGMC cohort was supported by INSERM, APHP, UPMC Univ Paris 06, ANR (R09186DS), DGS, VLM, and AICM., Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Neurophysiologie Respiratoire Expérimentale et Clinique (UMRS 1158), Mucoviscidose: physiopathologie et phénogénomique [CRSA], Centre de Recherche Saint-Antoine (CRSA), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU), Service de Pneumologie pédiatrique [CHU Trousseau], CHU Trousseau [APHP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU), Sorbonne Université - Faculté de Médecine (SU FM), Sorbonne Université (SU), Centre de Ressources et de Compétences en Mucoviscidose [CHU Toulouse] (CRCM Toulouse), Service Pneumologie et allergologie pédiatrique [CHU Toulouse], Pôle Enfants [CHU Toulouse], Centre Hospitalier Universitaire de Toulouse (CHU Toulouse)-Centre Hospitalier Universitaire de Toulouse (CHU Toulouse)-Pôle Enfants [CHU Toulouse], Centre Hospitalier Universitaire de Toulouse (CHU Toulouse)-Centre Hospitalier Universitaire de Toulouse (CHU Toulouse), and BMC, BMC
Background Lung disease progression is variable among cystic fibrosis (CF) patients and depends on DNA mutations in the CFTR gene, polymorphic variations in disease modifier genes, and environmental exposure. The contribution of genetic factors has been extensively investigated, whereas the mechanism whereby environmental factors modulate the lung disease is unknown. In this project, we hypothesized that (i) reiterative stress alters the epigenome in CF-affected tissues and (ii) DNA methylation variations at disease modifier genes modulate the lung function in CF patients. Results We profiled DNA methylation at CFTR, the disease-causing gene, and at 13 lung modifier genes in nasal epithelial cells and whole blood samples from 48 CF patients and 24 healthy controls. CF patients homozygous for the p.Phe508del mutation and ≥18-year-old were stratified according to the lung disease severity. DNA methylation was measured by bisulfite and next-generation sequencing. The DNA methylation profile allowed us to correctly classify 75% of the subjects, thus providing a CF-specific molecular signature. Moreover, in CF patients, DNA methylation at specific genes was highly correlated in the same tissue sample. We suggest that gene methylation in CF cells may be co-regulated by disease-specific trans-factors. Three genes were differentially methylated in CF patients compared with controls and/or in groups of pulmonary severity: HMOX1 and GSTM3 in nasal epithelial samples; HMOX1 and EDNRA in blood samples. The association between pulmonary severity and DNA methylation at EDNRA was confirmed in blood samples from an independent set of CF patients. Also, lower DNA methylation levels at GSTM3 were associated with the GSTM3*B allele, a polymorphic 3-bp deletion that has a protective effect in cystic fibrosis. Conclusions DNA methylation levels are altered in nasal epithelial and blood cell samples from CF patients. Analysis of CFTR and 13 lung disease modifier genes shows DNA methylation changes of small magnitude: some of them are a consequence of the disease; other changes may result in small expression variations that collectively modulate the lung disease severity. Electronic supplementary material The online version of this article (doi:10.1186/s13148-016-0300-8) contains supplementary material, which is available to authorized users.