title: Marked methylation changes in intestinal genes during the perinatal period of preterm neonates.
abstract: BACKGROUND
  The serious feeding- and microbiota-associated intestinal disease, necrotizing enterocolitis (NEC), occurs mainly in infants born prematurely (5-10% of all newborns) and most frequently after formula-feeding. We hypothesized that changes in gene methylation is involved in the prenatal maturation of the intestine and its response to the first days of formula feeding, potentially leading to NEC in preterm pigs used as models for preterm infants.
  
  
  RESULTS
  Reduced Representation Bisulfite Sequencing (RRBS) was used to assess if changes in intestinal DNA methylation are associated with formula-induced NEC outbreak and advancing age from 10 days before birth to 4 days after birth. Selected key genes with differentially methylated gene regions (DMRs) between groups were further validated by HiSeq-based bisulfite sequencing PCR and RT-qPCR to assess methylation and expression levels. Consistent with the maturation of many intestinal functions in the perinatal period, methylation level of most genes decreased with advancing pre- and postnatal age. The highest number of DMRs was identified between the newborn and 4 d-old preterm pigs. There were few intestinal DMR differences between unaffected pigs and pigs with initial evidence of NEC. In the 4 d-old formula-fed preterm pigs, four genes associated with intestinal metabolism (CYP2W1, GPR146, TOP1MT, CEND1) showed significant hyper-methylation in their promoter CGIs, and thus, down-regulated transcription. Methylation-driven down-regulation of such genes may predispose the immature intestine to later metabolic dysfunctions and severe NEC lesions.
  
  
  CONCLUSIONS
  Pre- and postnatal changes in intestinal DNA methylation may contribute to high NEC sensitivity in preterm neonates. Optimizing gene methylation changes via environmental stimuli (e.g. diet, nutrition, gut microbiota), may help to make immature newborn infants more resistant to gut dysfunctions, both short and long term.
authors.forename: Fei
authors.initials: F
authors.lastname: Gao
authors.forename: Juyong
authors.initials: J
authors.lastname: Zhang
authors.forename: Pingping
authors.initials: P
authors.lastname: Jiang
authors.forename: Desheng
authors.initials: D
authors.lastname: Gong
authors.forename: Jun-Wen
authors.initials: JW
authors.lastname: Wang
authors.forename: Yudong
authors.initials: Y
authors.lastname: Xia
authors.forename: Mette Viberg
authors.initials: MV
authors.lastname: Østergaard
authors.affiliation: Department of Science & Technology, BGI-Shenzhen, Shenzhen, China. wangj@genomics.org.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Per Torp
authors.initials: PT
authors.lastname: Sangild
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D019175:DNA Methylation; D020345:Enterocolitis, Necrotizing / Q000235:genetics / Q000378:metabolism; D044127:Epigenesis, Genetic; D005260:Female; D005865:Gestational Age; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D047928:Premature Birth / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA; D034421:Sus scrofa