Gastroenterology
Volume 136, Issue 7 , Pages 2325-2333, June 2009

Intrahepatic Bile Ducts Develop According to a New Mode of Tubulogenesis Regulated by the Transcription Factor SOX9

  • Aline Antoniou

      Affiliations

    • Université catholique de Louvain, de Duve Institute, Brussels, Belgium
    • ,
  • Peggy Raynaud

      Affiliations

    • Université catholique de Louvain, de Duve Institute, Brussels, Belgium
    • ,
  • Sabine Cordi

      Affiliations

    • Université catholique de Louvain, de Duve Institute, Brussels, Belgium
    • ,
  • Yiwei Zong

      Affiliations

    • Division of Gastroenterology, Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
    • ,
  • François Tronche

      Affiliations

    • CNRS UMR 7148, Institut de Biologie, Collège de France, Paris, France
    • ,
  • Ben Z. Stanger

      Affiliations

    • Division of Gastroenterology, Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
    • ,
  • Patrick Jacquemin

      Affiliations

    • Université catholique de Louvain, de Duve Institute, Brussels, Belgium
    • ,
  • Christophe E. Pierreux

      Affiliations

    • Université catholique de Louvain, de Duve Institute, Brussels, Belgium
    • ,
  • Frederic Clotman

      Affiliations

    • Université catholique de Louvain, de Duve Institute, Brussels, Belgium
    • ,
  • Frederic P. Lemaigre

      Affiliations

    • Université catholique de Louvain, de Duve Institute, Brussels, Belgium
    • Corresponding Author InformationReprint requests Address requests for reprints to: F. P. Lemaigre, MD, Université catholique de Louvain, de Duve Institute, Avenue Hippocrate 75/7529, 1200 Brussels, Belgium. fax: (32) 2 764 7507

Received 28 August 2008; accepted 6 February 2009. published online 23 February 2009.

Background & Aims

A number of diseases are characterized by defective formation of the intrahepatic bile ducts. In the embryo, hepatoblasts differentiate to cholangiocytes, which give rise to the bile ducts. Here, we investigated duct development in mouse liver and characterized the role of the SRY-related HMG box transcription factor 9 (SOX9).

Methods

We identified SOX9 as a new biliary marker and used it in immunostaining experiments to characterize bile duct morphogenesis. The expression of growth factors was determined by in situ hybridization and immunostaining, and their role was studied on cultured hepatoblasts. SOX9 function was investigated by phenotyping mice with a liver-specific inactivation of Sox9.

Results

Biliary tubulogenesis started with formation of asymmetrical ductal structures, lined on the portal side by cholangiocytes and on the parenchymal side by hepatoblasts. When the ducts grew from the hilum to the periphery, the hepatoblasts lining the asymmetrical structures differentiated to cholangiocytes, thereby allowing formation of symmetrical ducts lined only by cholangiocytes. We also provide evidence that transforming growth factor-β promotes differentiation of the hepatoblasts lining the asymmetrical structures. In the absence of SOX9, the maturation of asymmetrical structures into symmetrical ducts was delayed. This was associated with abnormal expression of CCAAT/Enhancer Binding Protein α and Homolog of Hairy/Enhancer of Split-1, as well as of the transforming growth factor-β receptor type II, which are regulators of biliary development.

Conclusions

Our results suggest that biliary development proceeds according to a new mode of tubulogenesis characterized by transient asymmetry and whose timing is controlled by SOX9.

Abbreviations used in this paper: C/EBPα, CCAAT/Enhancer Binding Protein α, ECM, extracellular matrix, HES1, Homolog of Hairy/Enhancer of Split-1, Hex, hematopoietically expressed homeobox factor, HNF, Hepatocyte Nuclear Factor, OPN, osteopontin, PDS, primitive ductal structures, SOX9, SRY-related HMG box transcription factor 9, TGF-β, transforming growth factor β, TβRII, transforming growth factor β receptor type II

 

 Conflicts of interest The authors disclose no conflicts.

 Funding Supported by the Interuniversity Attraction Poles Program (Belgian Science Policy; to F.L.), the D.G. Higher Education and Scientific Research of the French Community of Belgium (to F.L.), the Alphonse and Jean Forton Fund (to F.L.), and the Fund for Scientific Medical Research (to F.L.); and by NIH grant DK076583 (to B.Z.S.).A.A. and P.R. hold fellowships from the Université catholique de Louvain. F.C., C.P., and P.J. are research associates of the F.R.S.-F.N.R.S.

PII: S0016-5085(09)00300-X

doi:10.1053/j.gastro.2009.02.051

Gastroenterology
Volume 136, Issue 7 , Pages 2325-2333, June 2009