In Inflamed Intestinal Tissues and Epithelial Cells, Interleukin 22 Signaling Increases Expression of H19 Long Noncoding RNA, Which Promotes Mucosal Regeneration

Geng, H.; Bu, H. F.; Liu, F.; Wu, L.; Pfeifer, K.; Chou, P. M.; Wang, X.; Sun, J.; Lu, L.; Pandey, A.; Bartolomei, M. S.; De Plaen, I. G.; Wang, P.; Yu, J.; Qian, J.; Tan, X. D.

Gastroenterology. 2018 Apr 6

Abstract

BACKGROUND & AIMS: Inflammation affects regeneration of the intestinal epithelia; long non-coding RNAs (lncRNAs) regulate cell functions such as proliferation, differentiation, and migration. We investigated the mechanisms by which the lncRNA H19, imprinted maternally expressed transcript (H19) regulates regeneration of intestinal epithelium using cell cultures and mouse models of inflammation. METHODS: We performed RNA-seq transcriptome analyses of intestinal tissues from mice with LPS-induced sepsis to identify lncRNAs associated with inflammation; findings were confirmed by quantitative real-time PCR and in situ hybridization analyses of intestinal tissues from mice with sepsis or dextran sulfate sodium (DSS)-induced mucosal wound healing and patients with ulcerative colitis, compared to healthy individuals (controls). We screened cytokines for their ability to induce expression of H19 in HT-29 cells and intestinal epithelial cells (IECs), and confirmed findings in crypt epithelial organoids derived from mouse small intestine. IECs were incubated with different signal transduction inhibitors and effects on H19 lncRNA levels were measured. We assessed intestinal epithelial proliferation or regeneration in H19(DeltaEx1/+) mice given lipopolysaccharide (LPS) or DSS vs wild-type littermates (control mice). H19 was overexpressed in IECs using lentiviral vectors and cell proliferation was measured. We performed RNA antisense purification, RNA immunoprecipitation, and luciferase reporter assays to study functions of H19 in IECs. RESULTS: In RNA-seq transcriptome analysis of lncRNA expression in intestinal tissues from mice, we found levels of only H19 to change significantly with LPS exposure. Levels of H19 lncRNA increased in intestinal tissues of patients with ulcerative colitis, mice with LPS-induced sepsis, or mice with DSS-induced colitis, compared with controls. Increased H19 lncRNA localized to epithelial cells in the intestine, regardless of Lgr5 mRNA expression. Exposure of IECs to interleukin 22 (IL22) increased levels of H19 lncRNA with time and dose, which required STAT3 and PKA activity. IL22 induced expression of H19 in mouse intestinal epithelial organoids within 6 hours. Exposure to IL22 increased growth of intestinal epithelial organoids derived from control mice but not H19(DeltaEx1/+) mice. Overexpression of H19 in HT-29 cells increased their proliferation. Intestinal mucosa healed more slowly after withdrawal of DSS from H19(DeltaEx1/+) mice vs control mice. Crypt epithelial cells from H19(DeltaEx1/+) mice proliferated more slowly than those from control mice after exposure to LPS. H19 lncRNA bound to p53 and microRNAs that inhibit cell proliferation, including microRNA 34a and let-7; H19 lncRNA binding blocked their function, leading to increased expression of genes that promote regeneration of the epithelium. CONCLUSIONS: The level of lncRNA H19 is increased in inflamed intestinal tissues from mice and patients. The inflammatory cytokine IL22 induces expression of H19 in IECs, which is required for intestinal epithelial proliferation and mucosal healing. H19 lncRNA appears to inhibit p53 protein and microRNA 34a and let-7 to promote proliferation of intestinal epithelial cells and epithelial regeneration.

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