Human iPSC-derived hepatocyte system models cholestasis with tight junction protein 2 deficiency

Area of Science:

• Hepatology
• Stem Cell Biology
• Genetic Liver Diseases

Background:

• Truncating mutations in tight junction protein 2 (TJP2) lead to progressive cholestasis, liver failure, and hepatocyte carcinogenesis.
• Lack of effective disease models hinders the development of targeted therapies for TJP2 deficiency-related liver pathology.

Purpose of the Study:

• To establish a patient-specific induced pluripotent stem cell (iPSC)-based disease model that recapitulates the phenotypes of TJP2 deficiency.
• To utilize CRISPR genome-editing technology for precise genetic modification in the disease model.

Main Methods:

• Differentiated iPSCs into hepatocyte-like cells (iHEPs) in a polarized monolayer on Transwell membranes.
• Assessed epithelial barrier function and bile acid transport across bile canaliculi using live-confocal imaging and fluorescent probes.
• Quantified morphology of bile canaliculi in iHEPs cultured within a Matrigel sandwich system.

Main Results:

• TJP2-mutant iHEPs displayed disrupted apical membrane structures and distorted bile canalicular networks.
• Altered distribution of apical and basolateral markers/transporters was observed in mutant hepatocytes.
• Directional bile acid transport was compromised in TJP2-deficient iHEPs, mirroring patient phenotypes.

Conclusions:

• The iPSC-derived in vitro hepatocyte system effectively models canalicular membrane disruption in TJP2-deficient hepatocytes.
• This model serves as a valuable platform for further pathophysiological studies and the discovery of targeted drug therapies for cholestatic diseases caused by TJP2 deficiency.