Epigenetic mechanisms regulate T helper 17 and T regulatory cells during pregnancy in Multiple Sclerosis
Simona Rolla1, Valentina Bardina1, Andrea Iannello1, Alessandro Maglione1, Stefania De Mercanti1, Giorgia Puorro2, Roberta Lanzillo2, Cinzia Cordioli3, Mariavittoria Turrini3, Michele De Bortoli1, Santina Cutrupi1, and Marinella Clerico1
1Department of Clinical and Biological Sciences, University of Torino, 10043, Orbassano (TO), Italy
2Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples Federico II, 80131, Napoli, Italy
3Multiple Sclerosis Center, Spedali Civili di Brescia, 25018,Montichiari Hospital, Montichiari, Italy
Background: Increasing evidences support the anti-inflammatory role of estrogens in Multiple Sclerosis (MS), originating from the observation of reduction in relapse rates among women with MS during pregnancy. Estrogens (E2) act by binding Estrogen Receptors (ER) α and β that, functioning as ligand-activated transcription factors (TFs), bind specific DNA sequences, associate chromatin remodelers and TFs, and therefore regulate a broad range of estrogen-responsive genes. Aims: we studied estrogen effects mediated by ERα signaling during T helper (Th)17 cells polarization and in pregnant Relapsing Remitting (RR)MS patients.
Methods: A bioinformatic approach was used to selected Th17 and Treg cell-type-specific regulatory regions (CSR) regulated by ERα on RORC and FOXP3 loci, as they has been identified as candidate targets of estrogenic signaling in Th17 and Treg cells. PBMC from Healthy Donors (HD) were activated under Th17 polarizing condition for 3 days to test the effects of 17β-estradiol (E2) treatment at pregnancy concentration on the selected CSRs, the mRNA levels of RORC and
FOXP3 and the percentage of Th17 and Treg cells. PBMC from 15 pregnant RRMS and 15
pregnant HD were analyzed by FACS for Th17 and Treg cells and by Cromatin immunoprecipitation for CSRs in the III trimester of pregnancy (T3) and in the post partum (pp). Results: CD4+ T cells from MS patients expressed higher level of ERα compared to HD especially in the Th17 cell compartment. In vitro treatment with E2 induced active histone marks enrichment at FOXP3-CSRs and repressive histone marks enrichment at RORC-CSRs in polarized Th17 cells. These epigenetic changes reflected an enhanced FOXP3 and an impaired RORC mRNA expression with consequent significant inhibition of Th17 cells expansion. We found a MS specific epigenetic profile characterized by activation of FOXP3-CSRs and inactivation of RORC-CSRs during the T3 and by the activation of RORC-CSRs and the inactivation of FOXP3-CSRs during the pp. These results indicate a FOXP3 positive regulation and a RORC negative regulation that goes along with the decrease of Th17 cells and the increase of Treg cells observed in T3.
Conclusions: these data indicate that estrogens can act as immunomodulatory factors on the epigenomes of CD4+ T cells in MS; the identified CSRs may so represent potential biomarkers for monitoring disease progression or new potential therapeutic target.
DISCLOSURES: S Rolla: received travel grants from Sanofi-Genzyme; V Bardina: none; A Iannello: none; A Maglione: none; S De Mercanti: none; G Puorro: none; R Lanzillo: received personal compensation from Merck Serono, Biogen, Novartis, Almirall, Genzyme, and TEVA for
public speaking, editorial work and advisory boards; C Cordioli: none; M Turrini: none; M De Bortoli: none; S Cutrupi: none; M Clerico received personal compensations for advisory boards, public speaking, editorial commitments or travel grants from Biogen Idec, Merck Serono, Fondazione Serono, Novartis,Pomona, Sanofi-Genzyme and Teva.
