184-OR: In Utero Exposure to Gestational Diabetes Alters the Transcriptome and Methylome of Human Fetal Stem Cells Revealing an Enrichment of Interferon Related Pathways

Abstract

Background: Gestational diabetes (GDM) has profound effects on the intrauterine metabolic milieu, induces marked abnormalities in fetal glucose and insulin secretion and is linked to obesity and diabetes in the offspring, but the mechanisms remain largely unknown. Objective: To measure changes in gene expression and genome wide DNA methylation in human amniocytes, a fetal stem cell, exposed to GDM in utero. Methods: EdgeR identified differentially expressed genes from RNASeq via fold change, p-values, and q-values calculated after Bonferoni correction (n=8; 4 per sex). RNA-Seq results were confirmed via QPCR. Ingenuity Pathway Analysis (IPA) identified enriched biological pathways. Differentially methylated regions (DMRs) were determined from Enhanced Reduced Representation Bisulfite Sequencing (ERRBS) (n=16; 8 per sex) by identifying sequential CpGs with significant changes in DNA methylation >5%, and with p<0.05 over the entire DMR. Results: We identified 20 differentially expressed genes (q<0.10) analyzing data from male and female amniocytes together, but only 4 genes in male only and 2 in female only analyses. Using a significance threshold of p<0.01, we identified 65 differentially expressed genes analyzing all samples together, 46 genes in the male only and 68 in the female only analyses. QPCR confirmed increases in IFI44, ULBP1 and SAMD9L. Differentially expressed genes were strongly enriched for interferon inducible proteins, a novel fetal programming pathway after in utero GDM exposure. IPA showed enrichment in molecular mechanisms of growth, oxidative stress metabolism and GCPR signaling pathways. Offspring sex-specific analysis greatly enhanced DMR identification. Nine DMRs were identified in all, 41 in male and 20 in female samples. Conclusion: Exposure to GDM in utero leads changes in amniocyte gene expression and DNA methylation with enrichment in interferon inducible pathways. Disclosure S.E. Pinney: None. A. Joshi: None. V. Yin: None. S. Min: None. D.E. Condon: None. Z. Wang: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases (K08DK090302); National Institute of Environmental Health Sciences (P30ES013508); National Institutes of Health (UL1TR001878)