GSE53747
Marked methylation changes of intestinal genes in the neonatal period of preterm neonates
We hypothesized that the immature pig intestine would be highly sensitive to gene methylation changes in the immediate prenatal and neonatal periods. We performed a Reduced Representation Bisulfite Sequencing (RRBS) to assess the DNA methylation differences occurring during the last 10 days prenatally (PN, 0d-term vs. 0d-preterm), neonatally after 4 days (NN, 4d-preterm vs. 0d-preterm) and after NEC development (4d-preterm-NEC vs. 4d-preterm) in pigs (each group n=2-3). Differentially methylated gene regions (DMRs) between the groups were identified, subjected to KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis and selected genes were chosen for further validation of gene expression levels by RT-PCR (n= 6 for each group). Consistent with the need to increase expression of many intestinal genes in the perinatal period, methylation levels of most genes decreased during the prenatal and neonatal periods. We identified four intestinal genes (CYP2W1, GPR146, TOP1MT, CEND1), related to intestinal metabolism, that were significantly hyper-methylated in their promoter CGIs, and transcriptionally down-regulated in the 4 d-old preterm pigs. This down-regulation of intestinal metabolism may predispose to intestinal dysfunction and NEC. The first enteral feeds and bacterial colonization are critical factors for NEC sensitivity and it remains to be investigated whether these factors affect intestinal gene methylation and thereby predispose to, or prevent from, disease more long term. Overall design: We performed a Reduced Representation Bisulfite Sequencing (RRBS) to assess the DNA methylation differences occurring during the last 10 days prenatally (PN, 0d-term vs. 0d-preterm), neonatally after 4 days (NN, 4d-preterm vs. 0d-preterm) and after NEC development (4d-preterm-NEC vs. 4d-preterm) in pigs (each group n=2-3). Differentially methylated gene regions (DMRs) between the groups were identified, subjected to KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis and selected genes were chosen for further validation of gene expression levels by RT-PCR (n= 6 for each group).