1764-P: Assessing Gene Expression Profile and Insulin Secretion in Human Beta Cells (EndoC-BH3) under Glucose Exposure

Maternal diabetes is a risk factor for type 2 diabetes in the offspring, and in utero exposure to high glucose has been shown to affect pancreatic beta cell development in animal models. However, the developmental stage and specific genes which underlie these effects in humans are unknown. We aimed to understand the consequences of high glucose on the fetal pancreas by treating a human beta cell line derived from fetal pancreas, EndoC-BH3, with high, medium and normal glucose (30, 15 and 5.5mM respectively) for 3 weeks during proliferation and maturation and comparing gene expression using whole transcriptome analysis. The top differentially expressed transcripts (P10.5) were validated by real-time RT-PCR. KEGG analyses of the top 500 differentially expressed transcripts identified the metabolic pathway as the top pathway. Among individual genes, high glucose exposure during the maturation upregulated EGR1 (58.6-fold), BIRC5 (37.6-fold), GPBAR1 (15.4-fold), G6PC2 (11.8-fold), CHRNA (4.8-fold), GCK (2.7-fold), INS (2.0-fold), CMIP (1.9-fold) and CHGA (1.4-fold) as compared to normal glucose exposure. EGR1 encodes early-growth response 1, a transcription factor that enhances insulin gene expression, while BIRC5 encodes an apoptotic inhibitor that plays a role in beta cell proliferation. High glucose exposure during the proliferation identified similar differentially expressed genes; however, the changes were more modest as compared with the maturation. Methylation has also been implicated in conveying risk for diabetes due to glucose exposure and several key DNA demethylation enzymes; TET1, 2, 3, were also moderately upregulated. Assessment of the effects of glucose exposure on insulin secretion and total insulin content is ongoing. Our data suggest that short term exposure to high glucose may stimulate expression of a set of genes that promote beta cell proliferation and insulin expression and secretion.