Activation of the developmental pathway neurogenin-3/microRNA-7a regulates cholangiocyte proliferation in response to injury

Hepatology. 2014 Oct;60(4):1324-35. doi: 10.1002/hep.27262. Epub 2014 Aug 25.


The activation of the biliary stem-cell signaling pathway hairy and enhancer of split 1/pancreatic duodenal homeobox-1 (Hes-1/PDX-1) in mature cholangiocytes determines cell proliferation. Neurogenin-3 (Ngn-3) is required for pancreas development and ductal cell neogenesis. PDX-1-dependent activation of Ngn-3 initiates the differentiation program by inducing microRNA (miR)-7 expression. Here we investigated the role Ngn-3 on cholangiocyte proliferation. Expression levels of Ngn-3 and miR-7 isoforms were tested in cholangiocytes from normal and cholestatic human livers. Ngn-3 was knocked-down in vitro in normal rat cholangiocytes by short interfering RNA (siRNA). In vivo, wild-type and Ngn-3-heterozygous (+/-) mice were subjected to 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) feeding (a model of sclerosing cholangitis) or bile duct ligation (BDL). In the liver, Ngn-3 is expressed specifically in cholangiocytes of primary sclerosing cholangitis (PSC) patients and in mice subjected to DDC or BDL, but not in normal human and mouse livers. Expression of miR-7a-1 and miR-7a-2 isoforms, but not miR-7b, was increased in DDC cholangiocytes compared to normal ones. In normal rat cholangiocytes, siRNA against Ngn-3 blocked the proliferation stimulated by exendin-4. In addition, Ngn-3 knockdown neutralized the overexpression of insulin growth factor-1 (IGF1; promitotic effector) observed after exposure to exendin-4, but not that of PDX-1 or VEGF-A/C. Oligonucleotides anti-miR-7 inhibited the exendin-4-induced proliferation in normal rat cholangiocytes, but did not affect Ngn-3 synthesis. Biliary hyperplasia and collagen deposition induced by DDC or BDL were significantly reduced in Ngn-3(+/-) mice compared to wild-type.

Conclusion: Ngn-3-dependent activation of miR-7a is a determinant of cholangiocyte proliferation. These findings indicate that the reacquisition of a molecular profile typical of organ development is essential for the biological response to injury by mature cholangiocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Lung Injury / metabolism
  • Acute Lung Injury / physiopathology*
  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / drug effects
  • Basic Helix-Loop-Helix Transcription Factors / genetics
  • Basic Helix-Loop-Helix Transcription Factors / physiology*
  • Bile Ducts / metabolism
  • Bile Ducts / pathology
  • Bile Ducts / physiopathology*
  • Cell Proliferation / physiology*
  • Cholestasis / metabolism
  • Cholestasis / pathology
  • Cholestasis / physiopathology*
  • Collagen / metabolism
  • Disease Models, Animal
  • Exenatide
  • Humans
  • In Vitro Techniques
  • Insulin-Like Growth Factor I / metabolism
  • Mice
  • Mice, Inbred Strains
  • MicroRNAs / physiology*
  • Nerve Tissue Proteins / drug effects
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / physiology*
  • Oligonucleotides / pharmacology
  • Peptides / metabolism
  • RNA, Small Interfering / pharmacology
  • Rats
  • Signal Transduction / physiology*
  • Venoms / metabolism


  • Basic Helix-Loop-Helix Transcription Factors
  • MIRN7 microRNA, human
  • MicroRNAs
  • NEUROG3 protein, human
  • Nerve Tissue Proteins
  • Oligonucleotides
  • Peptides
  • RNA, Small Interfering
  • Venoms
  • Insulin-Like Growth Factor I
  • Collagen
  • Exenatide