2. Academic Validation
  3. Loss of fibrocystin promotes interleukin-8-dependent proliferation and CTGF production of biliary epithelium

Loss of fibrocystin promotes interleukin-8-dependent proliferation and CTGF production of biliary epithelium

  • J Hepatol. 2019 Jul;71(1):143-152. doi: 10.1016/j.jhep.2019.02.024.
Tomoyuki Tsunoda 1,  Sei Kakinuma 2,  Masato Miyoshi 1,  Akihide Kamiya 3,  Shun Kaneko 1,  Ayako Sato 1,  Jun Tsuchiya 1,  Sayuri Nitta 1,  Fukiko Kawai-Kitahata 1,  Miyako Murakawa 1,  Yasuhiro Itsui 1,  Mina Nakagawa 1,  Seishin Azuma 1,  Tsuyoshi Sogo 4,  Haruki Komatsu 5,  Ryutaro Mukouchi 6,  Ayano Inui 4,  Tomoo Fujisawa 4,  Hiromitsu Nakauchi 7,  Yasuhiro Asahina 8,  Mamoru Watanabe 9
Affiliations

Affiliations

  • 1 Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
  • 2 Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University (TMDU), Tokyo, Japan; Department of Liver Disease Control, Tokyo Medical and Dental University (TMDU), Tokyo, Japan. Electronic address: [email protected].
  • 3 Department of Molecular Life Sciences, School of Medicine, Tokai University, Isehara, Japan.
  • 4 Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohamashi Tobu Hospital, Yokohama, Japan.
  • 5 Department of Pediatrics, Toho University Sakura Medical Center, Sakura, Japan.
  • 6 Department of Pathology, Saiseikai Yokohamashi Tobu Hospital, Yokohama, Japan.
  • 7 Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA; Division of Stem Cell Therapy, Institute of Medical Science, The University of Tokyo, Tokyo, Japan.
  • 8 Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University (TMDU), Tokyo, Japan; Department of Liver Disease Control, Tokyo Medical and Dental University (TMDU), Tokyo, Japan. Electronic address: [email protected].
  • 9 Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University (TMDU), Tokyo, Japan. Electronic address: [email protected].
PMID: 30898581 DOI: 10.1016/j.jhep.2019.02.024
Abstract

Background & aims: Congenital hepatic fibrosis (CHF) is a genetic liver disease resulting in abnormal proliferation of cholangiocytes and progressive hepatic fibrosis. CHF is caused by mutations in the PKHD1 gene and the subsequent dysfunction of the protein it encodes, fibrocystin. However, the underlying molecular mechanism of CHF, which is quite different from liver cirrhosis, remains unclear. This study investigated the molecular mechanism of CHF pathophysiology using a genetically engineered human induced pluripotent stem (iPS) cell model to aid the discovery of novel therapeutic agents for CHF.

Methods: PKHD1-knockout (PKHD1-KO) and heterozygously mutated PKHD1 iPS clones were established by RNA-guided genome editing using the CRISPR/Cas9 system. The iPS clones were differentiated into cholangiocyte-like cells in cysts (cholangiocytic cysts [CCs]) in a 3D-culture system.

Results: The CCs were composed of a monolayer of cholangiocyte-like cells. The proliferation of PKHD1-KO CCs was significantly increased by interleukin-8 (IL-8) secreted in an autocrine manner. IL-8 production was significantly elevated in PKHD1-KO CCs due to mitogen-activated protein kinase pathway activation caused by fibrocystin deficiency. The production of connective tissue growth factor (CTGF) was also increased in PKHD1-KO CCs in an IL-8-dependent manner. Furthermore, validation analysis demonstrated that both the serum IL-8 level and the expression of IL-8 and CTGF in the liver samples were significantly increased in patients with CHF, consistent with our in vitro human iPS-disease model of CHF.

Conclusions: Loss of fibrocystin function promotes IL-8-dependent proliferation of, and CTGF production by, human cholangiocytes, suggesting that IL-8 and CTGF are essential for the pathogenesis of CHF. IL-8 and CTGF are candidate molecular targets for the treatment of CHF.

Lay summary: Congenital hepatic fibrosis (CHF) is a genetic liver disease caused by mutations of the PKHD1 gene. Dysfunction of the protein it encodes, fibrocystin, is closely associated with CHF pathogenesis. Using an in vitro human induced pluripotent stem cell model and patient samples, we showed that the loss of fibrocystin function promotes proliferation of cholangiocytes and the production of connective tissue growth factor (CTGF) in an interleukin 8 (IL-8)-dependent manner. These results suggest that IL-8 and CTGF are essential for the pathogenesis of CHF.

Keywords

Congenital hepatic fibrosis; Ductal plate malformation; Fibrocystin; Hepatic progenitor-like cells; Human induced pluripotent stem cells; Liver transplantation; PKHD1; Polycystic kidney and hepatic disease 1.

Figures