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Transgenic Expression of miR-222 Disrupts Intestinal Epithelial Regeneration by Targeting Multiple Genes Including Frizzled-7.

ABSTRACT: Defects in intestinal epithelial integrity occur commonly in various pathologies. miR-222 is implicated in many aspects of cellular function and plays an important role in several diseases, but its exact biological function in the intestinal epithelium is underexplored. We generated mice with intestinal epithelial tissue-specific overexpression of miR-222 to investigate the function of miR-222 in intestinal physiology and diseases in vivo. Transgenic expression of miR-222 inhibited mucosal growth and increased susceptibility to apoptosis in the small intestine, thus leading to mucosal atrophy. The miR-222-elevated intestinal epithelium was vulnerable to pathological stress, since local overexpression of miR-222 not only delayed mucosal repair after ischemia/reperfusion-induced injury, but also exacerbated gut barrier dysfunction induced by exposure to cecal ligation and puncture. miR-222 overexpression also decreased expression of the Wnt receptor Frizzled-7 (FZD7), cyclin-dependent kinase 4 and tight junctions in the mucosal tissue. Mechanistically, we identified the Fzd7 messenger ribonucleic acid (mRNA) as a novel target of miR-222 and found that [miR-222/Fzd7 mRNA] association repressed Fzd7 mRNA translation. These results implicate miR-222 as a negative regulator of normal intestinal epithelial regeneration and protection by downregulating expression of multiple genes including the Fzd7. Our findings also suggest a novel role of increased miR-222 in the pathogenesis of mucosal growth inhibition, delayed healing and barrier dysfunction.

SUBMITTER: Chung HK

PROVIDER: S-EPMC4749484 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature

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Transgenic Expression of miR-222 Disrupts Intestinal Epithelial Regeneration by Targeting Multiple Genes Including Frizzled-7.

Chung Hee Kyoung HK Chen Yu Y Rao Jaladanki N JN Liu Lan L Xiao Lan L Turner Douglas J DJ Yang Peixin P Gorospe Myriam M Wang Jian-Ying JY

Molecular medicine (Cambridge, Mass.) 20150803 1

Defects in intestinal epithelial integrity occur commonly in various pathologies. miR-222 is implicated in many aspects of cellular function and plays an important role in several diseases, but its exact biological function in the intestinal epithelium is underexplored. We generated mice with intestinal epithelial tissue-specific overexpression of miR-222 to investigate the function of miR-222 in intestinal physiology and diseases <i>in vivo</i>. Transgenic expression of miR-222 inhibited mucosa ...[more]

PMID: 26252186

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Project description:A microarray analysis of an animal model with experimental sepsis induced by caecal ligation and puncture revealed that the level of microRNA?195 (miR?195) was upregulated. However, to the best of our knowledge, the role of miR?195 in sepsis remains unknown. The present study investigated the effect of miR?195 on apoptosis in sepsis and investigated the underlying mechanism. The level of miR?195 was measured in human intestinal epithelial cells following exposure to lipopolysaccharide (LPS). Cell viability and apoptosis were detected using Cell Counting kit?8 and flow cytometry assays. The expression levels of apoptosis?associated proteins were determined using western blot analysis. In addition, a dual?luciferase reporter assay was employed to verify the association between miR?195 and sirtuin 1 (SIRT1). Furthermore, the SIRT1 inhibitor EX527 was applied to further confirm the regulatory network of miR?195/SIRT1 in LPS?induced apoptosis. It was demonstrated that LPS significantly inhibited cell viability and promoted cell apoptosis in NCM460 cells in a dose?dependent manner. In addition, miR?195 was significantly upregulated following LPS treatment. The present results revealed that silencing miR?195 prevented apoptosis and alleviated cell injury in LPS?induced NCM460 cells. Further investigation demonstrated that miR?195 bound directly to and negatively regulated SIRT1. Inhibition of SIRT1 reversed the protective effects of miR?195?silencing on the apoptosis and viability of NCM460 cells. Furthermore, silencing miR?195 prevented endoplasmic reticulum (ER) stress?induced apoptosis via a downregulation of SIRT1 and its downstream effectors, including activating transcription factor 4, C/EBP homologous protein, glucose?regulated protein 78 and growth arrest and DNA?damage protein 34, as well as the phosphorylation of eukaryotic translation initiation factor 2A. In conclusion, the present study revealed a novel mechanism by which miR?195 regulates SIRT1?mediated downstream effectors in ER stress?induced apoptosis in sepsis.

Project description:BackgroundEffective targeting therapies for common chronic liver disease nonalcoholic steatohepatitis (NASH) are in urgent need. MicroRNA-targeted therapeutics would be potentially an effective treatment strategy of hepatic diseases. Here we investigated the functional role of miR-221/222 and the therapeutic effects of antimiRs-221/222 in NASH mouse models.MethodsWe generated the miR-221/222flox/flox mice on a C57BL/6?J background and the hepatic miR-221/222 knockout (miR-221/222-LKO) mice. The mice were challenged with the methionine and choline deficient diet (MCDD) or chronic carbon tetrachloride (CCl4) treatment to generate experimental steatohepatitis models. Adenovirus-mediated re-expression of miR-221/222 was performed on the MCDD-fed miR-221/222-LKO mice. The MCDD and control diet-fed mice were treated with locked nucleic acid (LNA)-based antimiRs of miR-221/222 to evaluate the therapeutic effects. Histological analysis, RNA-seq, quantitative PCR and Western blot of liver tissues were carried out to study the hepatic lipid accumulation, inflammation and collagen deposition in mouse models.FindingsHepatic deletion of miR-221/222 resulted in significant reduction of liver fibrosis, lipid deposition and inflammatory infiltration in the MCDD-fed and CCl4-treated mouse models. The hepatic steatosis and fibrosis were dramatically aggravated by miR-221/222 re-expression in MCDD-fed miR-221/222-LKO mice. AntimiRs of miR-221/222 could effectively reduce the MCDD-mediated hepatic steatosis and fibrosis. Systematically mechanistic study revealed that hepatic miR-221/222 controlled the expression of target gene Timp3 and promoted the progression of NASH.InterpretationOur findings demonstrate that miR-221/222 are crucial for the regulation of lipid metabolism, inflammation and fibrosis in the liver. LNA-antimiRs targeted miR-221/222 could reduce steatohepatitis with prominent antifibrotic effect in NASH mice. FUND: This work is supported by the Natural Science Foundation of China (81530020, 81390352 to Dr. Ning and 81522032 to Dr. Cao and 81670793 to Dr. Jiang); National Key Research and Development Program (No. 2016YFC0905001 and 2017YFC0909703 to Dr. Cao); the Shanghai Rising-Star Program (15QA1402900 to Dr. Cao); Shanghai Municipal Education Commission-Gaofeng Clinical Medicine Grant (20171905 to Dr. Jiang).

Dataset Information

Transgenic Expression of miR-222 Disrupts Intestinal Epithelial Regeneration by Targeting Multiple Genes Including Frizzled-7.

Publications

Transgenic Expression of miR-222 Disrupts Intestinal Epithelial Regeneration by Targeting Multiple Genes Including Frizzled-7.

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