Contributions
Abstract: P748
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Genetics/Epigenetics
Background: Genome wide association studies and fine mapping have demonstrated association between single nucleotide polymorphisms (SNPs) within and near the IL2RA gene locus and risk of multiple sclerosis (MS). Yet, little is known on how these SNPs affect MS susceptibility. The MS risk SNP rs2104286 creates and disrupts a CpG-site and SNPs are known to affect local and more distant DNA methylation patterns, a phenomenon known as allele-specific methylation. In this study we have focused on epigenetic regulation of IL2RA in CD8 T cells. CD8 T cells are predominant in MS lesions and previous studies have shown pronounced differential gene expression and methylation in CD8 T cells between MS and controls.
Aims: To investigate the relation between the IL2RA loci SNPs, rs2104286 and rs11256593, DNA methylation and the effect on IL2RA gene expression in total CD8 T cells.
Methods: Total CD8 T cells were isolated from 52 healthy controls comprising 5 heterozygous, 25 homozygous for the risk allele (T) and 22 homozygous for the protective (C) allele of rs2104286 and rs11256593. DNA methylation status of six CpG-sites in the IL2RA promoter and one at the rs2104286 SNP were determined using PyroMarkQ24 pyrosequencing. A Nanostring NCounter® PanCancer Immune Profiling panel was used to measure gene expression levels.
Results: In total CD8 T cells we found a significant allele specific methylation at the rs2104286 CpG-site (chr.10:6,057,082) when comparing CC, CT and TT-risk carriers (p=0.0001). However, this methylation difference did not correlate with IL2RA gene expression. The IL2RA promoter methylation level of one CpG-site (chr10:6,062,684) was significantly different between healthy CC- and TT-carriers (p=0.048) and correlated with rs2104286 CpG methylation status (rho=0.33; p=0.02). In CD8 T cells only minor negative correlations were observed between the IL2RA promoter methylation and gene expression but interestingly, IL2RA promoter methylation correlated negatively with IL15RA gene expression (rho=-0.5;p< 0.001).
Conclusions: These results show that differential methylation at two CpG-sites in the IL2RA locus in CD8 T cells is associated with the gene variants rs2104286 and rs11256593, which could represent one mechanism to how they increase MS susceptibility, however, this methylation had no major effect on IL2RA gene expression in unstimulated CD8 T cells.
Disclosure: Helle Bach Søndergaard has received support for congress participation from Biogen Idec, Genzyme and Teva.
Hannah-Marie Laigaard reports no disclosures.
Sophie Buhelt reports no disclosures.
Marina Rode von Essen reports no disclosures.
Henrik Ullum has received an unrestricted research grant form Novartis.
Annette Oturai has served on scientific advisory boards for Novartis, and served as consultant for Biogen Idec; has received support for congress participation from Biogen Idec, Novartis, Sanofi Aventis and Teva; has received speaker honoraria from, Biogen Idec, Novartis, and Sanofi-Aventis.
Finn Sellebjerg has served on scientific advisory boards for Biogen, Merck, Novartis and Sanofi Genzyme; served as consultant for Biogen and EMD Serono; received support for congress participation from Biogen, Novartis, Roche and Teva; and received speaker honoraria from Biogen, Merck, Novartis, Sanofi Genzyme and Teva. Sellebjerg's laboratory has received research support from Biogen, EMD Serono, Sanofi Genzyme, Novartis and Roche.
Abstract: P748
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Genetics/Epigenetics
Background: Genome wide association studies and fine mapping have demonstrated association between single nucleotide polymorphisms (SNPs) within and near the IL2RA gene locus and risk of multiple sclerosis (MS). Yet, little is known on how these SNPs affect MS susceptibility. The MS risk SNP rs2104286 creates and disrupts a CpG-site and SNPs are known to affect local and more distant DNA methylation patterns, a phenomenon known as allele-specific methylation. In this study we have focused on epigenetic regulation of IL2RA in CD8 T cells. CD8 T cells are predominant in MS lesions and previous studies have shown pronounced differential gene expression and methylation in CD8 T cells between MS and controls.
Aims: To investigate the relation between the IL2RA loci SNPs, rs2104286 and rs11256593, DNA methylation and the effect on IL2RA gene expression in total CD8 T cells.
Methods: Total CD8 T cells were isolated from 52 healthy controls comprising 5 heterozygous, 25 homozygous for the risk allele (T) and 22 homozygous for the protective (C) allele of rs2104286 and rs11256593. DNA methylation status of six CpG-sites in the IL2RA promoter and one at the rs2104286 SNP were determined using PyroMarkQ24 pyrosequencing. A Nanostring NCounter® PanCancer Immune Profiling panel was used to measure gene expression levels.
Results: In total CD8 T cells we found a significant allele specific methylation at the rs2104286 CpG-site (chr.10:6,057,082) when comparing CC, CT and TT-risk carriers (p=0.0001). However, this methylation difference did not correlate with IL2RA gene expression. The IL2RA promoter methylation level of one CpG-site (chr10:6,062,684) was significantly different between healthy CC- and TT-carriers (p=0.048) and correlated with rs2104286 CpG methylation status (rho=0.33; p=0.02). In CD8 T cells only minor negative correlations were observed between the IL2RA promoter methylation and gene expression but interestingly, IL2RA promoter methylation correlated negatively with IL15RA gene expression (rho=-0.5;p< 0.001).
Conclusions: These results show that differential methylation at two CpG-sites in the IL2RA locus in CD8 T cells is associated with the gene variants rs2104286 and rs11256593, which could represent one mechanism to how they increase MS susceptibility, however, this methylation had no major effect on IL2RA gene expression in unstimulated CD8 T cells.
Disclosure: Helle Bach Søndergaard has received support for congress participation from Biogen Idec, Genzyme and Teva.
Hannah-Marie Laigaard reports no disclosures.
Sophie Buhelt reports no disclosures.
Marina Rode von Essen reports no disclosures.
Henrik Ullum has received an unrestricted research grant form Novartis.
Annette Oturai has served on scientific advisory boards for Novartis, and served as consultant for Biogen Idec; has received support for congress participation from Biogen Idec, Novartis, Sanofi Aventis and Teva; has received speaker honoraria from, Biogen Idec, Novartis, and Sanofi-Aventis.
Finn Sellebjerg has served on scientific advisory boards for Biogen, Merck, Novartis and Sanofi Genzyme; served as consultant for Biogen and EMD Serono; received support for congress participation from Biogen, Novartis, Roche and Teva; and received speaker honoraria from Biogen, Merck, Novartis, Sanofi Genzyme and Teva. Sellebjerg's laboratory has received research support from Biogen, EMD Serono, Sanofi Genzyme, Novartis and Roche.