727: Longitudinal evaluation of altered methylation in IL1 gene family in normal pregnancy

in IL1 gene family in normal pregnancy Wendy White, Brian Brost, Jonathan O’Brien, Elizabeth Baldwin, William Watson, Carl Rose, Norman Davies, Zhifu Sun, Stephen Turner, Ramakrishna Edukula, Vesna Garovic Mayo Clinic College of Medicine, Maternal Fetal Medicine, Rochester, MN, Mayo Clinic College of Medicine, Biomedical Statistics and Informatics, Rochester, MN, Mayo Clinic College of Medicine, Nephrology and Hypertension, Rochester, MN OBJECTIVE: The Interleukin 1 family contains Interleukin 1alpha (IL1a), Interleukin 1beta (IL1b), IL1 receptor antagonist (IL1RA) and two receptors ILR1 and 2. These are important proinflammatory mediators in the establishment/ maintenance of normal pregnancy. STUDY DESIGN: The methylation profiles of the IL1 family (10 CpG sites in 5 genes) were characterized in maternal DNA from blood longitudinally in 14 women at 16 weeks, at delivery and postpartum (n 42) and in 14 nulligravid women. All patients were non-smokers, matched for age and BMI. Genomic DNA was derived from buffy coat, purified, bisulfite modified and run on the Illumina Methylation Assay platform. Mean methylation levels at each site were compared using a Students or paired t-test. Serum IL1b levels were measured by high sensitivity ELISA. RESULTS: The mean beta values (methylation %) at 10 CpG sites in 5 IL1 genes are shown for each time point and for the nulligravid controls in the table below; values in bold represent statistically significant differences between pregnant and non-pregnant groups. Methylation patterns are similar in both non-pregnant groups postpartum and nulligravid. Methylation levels in the ILRA and IL1R1 do not change with pregnancy. IL1a, IL1b, and IL1R2 become less methylated in early pregnancy compared with postpartum levels (p 0.0005; p 0.0007; p 0.004/p 0.007) or nulligravid controls (p 0.03; p 0.006; p 0.00002/p 0.02) and hypomethylation persists or increases at delivery. Serum IL1 beta levels are higher in early pregnancy (mean 0.108 pg/mL) compared with normal values from the literature ( 0.05 pg/mL). CONCLUSION: Early normal pregnancy is associated with decreased methylation in IL1a, IL1b and ILR2 compared with non-pregnancy levels, which are the same regardless of parity. ILRA and ILR1 are unchanged. Serum IL1b levels, usually non-detectible in healthy controls, are increased in our early pregnancy cohort. Altered methylation in IL1 genes at different gestational time points may result in increased expression as demonstrated by increased IL1b serum levels associated with early pregnancy. 728 Methylation altered in IL1 family of genes in maternal DNA in preeclamptic versus normotensive pregnancy at time of delivery Wendy White, Brian Brost, Jonathan O’Brien, Elizabeth Baldwin, William Watson, Carl Rose, Norman Davies, Zhifu Sun, Stephen Turner, Vesna Garovic Mayo Clinic College of Medicine, Maternal Fetal Medicine, Rochester, MN, Mayo Clinic College of Medicine, Biomedical Statistics and Informatics, Rochester, MN, Mayo Clinic College of Medicine, Nephrology and Hypertension, Rochester, MN OBJECTIVE: The Interleukin 1 family contains Interleukin 1 alpha (IL1a), Interleukin 1 beta (IL1b), IL1 receptor antagonist (IL1RA) and two receptors (IL1R1 and IL1R2). Alterations in the IL1 family have been associated with preeclampsia (PE). IL1a allelic variants have been correlated with PE, but changes in serum levels have not been seen. Serum IL1b levels have been shown to be elevated in PE. Increased expression of IL1RA has been shown in leukocytes from PE women. DNA methylation is an epigenetic mechanism that can control gene expression. We sought to characterize the methylation patterns of 5 IL1 genes in maternal DNA in preeclamptic and normotensive pregnancies at the time of delivery. STUDY DESIGN: The methylation profiles of the IL1 family (10 CpG sites in 5 genes) were characterized in maternal leukocyte DNA from blood in 14 normotensive (NT) women and in 14 PE cases at the time of delivery. PE was diagnosed based on ACOG criteria. All patients were non-smokers, primigravidae and were matched for age and BMI. Genomic DNA was derived from buffy coat, purified, and bisulfite modified then run on the Illumina Methylation Assay platform. Mean methylation levels at each CpG site were compared using a Students t-test. RESULTS: Key CpG sites in the genes for IL1a (0.48 v. 0.44; p 0.01) and IL1b (0.27 v. 0.24; p 0.03; 0.22 v. 0.19; p 0.05) showed increased methylation in PE as compared with NT pregnancies at the time of delivery. Decreased methylation in IL1R1 (0.80 v. 0.83; p 0.03) was seen in PE. No significant difference was seen in methylation patterns in IL1R2 and ILRA. CONCLUSION: Methylation at key CpG sites was altered in the IL1a and IL1b genes (increased) and IL1R1 gene (decreased) in women with PE compared with NT women at the time of delivery. Increased methylation can result in decreased gene expression; our results contrast with the literature in terms of protein levels of IL1b in serum, while IL1a and IL1R1 levels have not been studied in PE. We postulate that increased methylation may represent an endogenous regulatory mechanism to ameliorate the proinflammatory state of PE. www.AJOG.org Academic Issues, Antepartum Fetal Assessment, Genetics, Hypertension, Medical-Surgical-Disease Poster Session V