Dental pulp stem cells maintain epigenetic chromatin architecture remodeling primed by the etiological stimulus of biliary atresia.

BACKGROUND

Biliary atresia (BA) is a nongenetic cholangiopathy characterized by biliary obliteration. However, the underlying pathological mechanism remains unclear. We aimed to explore the epigenetic BA pathology by using BA-specific deciduous dental pulp stem cells (BA-SHED), which develop in parallel with cholangiocyte progenitor cells in human embryos.

METHODS

BA-SHED were isolated from human exfoliated deciduous teeth of patients with BA using the colony-forming unit fibroblast method. After sequential stimulation with cytokines and chemicals in cultured BA-SHED, the in vitro bile duct-forming capacity was analyzed using quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunofluorescence. Expression of hepatocyte nuclear factor 6 (HNF6) and transforming growth factor beta receptor 2 (TGFBR2) was analyzed using immunoblotting and RT-qPCR. The regulation of chromatin architecture at the HNF6 promoter was analyzed using nuclease-accessible chromatin-qPCR and chromatin immunoprecipitation-qPCR.

RESULTS

BA-SHED showed an inheritable increase in HNF6 levels, resulting in TGFBR2 suppression and deficiency in bile duct formation. BA-SHED also accumulated Brahma and P65 complexes around the HNF6 promoter with chromatin architecture remodeling. Tumor necrosis factor-alpha and interferon-gamma co-stimulation mimicked the epigenetic signatures of BA-SHED.

CONCLUSION

The present epigenetic memory in BA-SHED implies that BA-SHED imprint bile duct deficiency through TGFBR2 dysregulated by the HNF6 promoter activation epigenetically. Thus, BA-SHED are a potential model for expanding our knowledge in BA research.