gastroenterologists-2018-scientifictracks

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Nov 15-16, 2018 | Paris, France

Gastroenterology and Digestive Disorders

International Conference on

Journal of Gastroenterology and Digestive Diseases | Volume 3

Epigenetic modulation of intestinal NHE3 expression by DNA methylation

Seema Saksena

University of Illinois, USA

HE3 plays an important role in Intestinal Na+ absorption and

its down-regulation has been implicated in infectious and

Inflammatory Bowel Diseases (IBD)-associated Diarrhea. Recent

evidence also indicates a novel role of epigenetic mechanisms,

such as DNA methylation in the pathophysiology of IBD. Whether

changes in DNA methylation are involved in modulating Intestinal

NHE3 gene expression is not known. Caco-2 and HUTU-80 cells

were used as models of Human Intestinal Epithelial Cells (IECs).

Normal C57/BL6, wild type or GADD45b KO mice were used as in

vivo models. NHE3 gene DNA methylation levels were assessed

by methyl-CpG binding domain-based capture assays. In vitro

methylation of NHE3 promoter construct (p-1509/+127) cloned

intoaCpGfreeluciavectordecreasedthepromoteractivityinCaco2

cells. DNA methyltransferase (DNMT) inhibitor, 5-azacytidine (10

mM, 24h) caused a significant decrease in DNAmethylation of the

NHE3 gene and concomitantly increased NHE3mRNA and protein

expression in Caco2 cells. Similarly, 5-aza treatment increased

NHE3 mRNA levels in HUTU-80 cells. 5-aza treatment for 3 weeks

(10 mg/kg body wt., i.p., 3x/wk) also resulted in an increase in

NHE3expression in themouse ileumandcolon. siRNAknockdown

of GADD45b (protein involved in DNA demethylation) in Caco2

cells decreased NHE3 mRNA expression. Furthermore, there was

a significant decrease in NHE3 mRNA and protein expression in

the ileum & colon of GADD45b KO mice. Our studies for the first

time demonstrate that NHE3 gene expression is regulated by an

epigenetic mechanism involving DNA methylation. These findings

suggest that changes in DNA methylation may be involved in the

inhibition of NHE3 Gene Expression in Intestinal Inflammation

contributing to the pathophysiology of IBD-associated Diarrhea.

Speaker Biography

Seema Saksena, PhD is a Research Associate professor under the section of Digestive

Diseases and Nutrition at University of Illinois at Chicago, USA. Shed did her PhD at Dr.

R. M. L. University in India, her postdoc at Central Drug Res Institute, India. She has

published more than 30 articles and abstracts.