Inhibition of nuclear factor (erythroid-derived 2)-like 2 promotes hepatic progenitor cell activation and differentiation

Francesco Bellanti,Rosanna Tamborra,Gaetano Serviddio,Giuseppe Pannone,Luke Boulter,Rosanna Villani,Giuseppina Iannelli,Wei-Yu Lu,Stuart J Forbes,Maria Carmela Pedicillo,Giorgia Di Bello,Gianluigi Vendemiale

doi:10.1038/s41536-021-00137-z

Abstract

The stem cell ability to self-renew and lead regeneration relies on the balance of complex signals in their microenvironment. The identification of modulators of hepatic progenitor cell (HPC) activation is determinant for liver regeneration and may improve cell transplantation for end-stage liver disease. This investigation used different models to point out the Nuclear factor (erythroid-derived 2)-like 2 (NRF2) as a key regulator of the HPC fate. We initially proved that in vivo models of biliary epithelial cells (BECs)/HPC activation show hepatic oxidative stress, which activates primary BECs/HPCs in vitro. NRF2 downregulation and silencing were associated with morphological, phenotypic, and functional modifications distinctive of differentiated cells. Furthermore, NRF2 activation in the biliary tract repressed the ductular reaction in injured liver. To definitely assess the importance of NRF2 in HPC biology, we applied a xenograft model by inhibiting NRF2 in the human derived HepaRG cell line and transplanting into SCID/beige mice administered with anti-Fas antibody to induce hepatocellular apoptosis; this resulted in effective human hepatocyte repopulation with reduced liver injury. To conclude, NRF2 inhibition leads to the activation and differentiation of liver progenitors. This redox-dependent transcription factor represents a potential target to regulate the commitment of undifferentiated hepatic progenitors into specific lineages.

Highlights

The ability of stem cells to self-renew, maintain pluripotency, and lead tissue regeneration relies on the balance of complex signals in their microenvironment
Statistical differences were assessed by one-way ANOVA and Tukey–Kramer as post hoc test. *p < 0.05 vs CTRL; **p < 0.01 vs CTRL; ^p < 0.05 vs H2O2. d mRNA expression of Notch and Wnt pathway targets in biliary epithelial cells (BECs)/hepatic progenitor cell (HPC) exposed to 1 μM H2O2 or 1 μM H2O2 + 1 mM N-acetylcysteine (NAC) for 24 h
To confirm the role of Nuclear factor (erythroidderived 2)-like 2 (NRF2) in HPC biology, we studied the ductular reaction in mice fed the methionine and choline-deficient (MCD) diet undergoing activation of NRF2 in the canals of Hering

Summary

Introduction

The ability of stem cells to self-renew, maintain pluripotency, and lead tissue regeneration relies on the balance of complex signals in their microenvironment. Liver renewal during normal homeostasis or after an acute injury is driven by hepatocytes; in case of severe or protracted damage, liver regeneration is mediated by hepatic progenitor cells (HPCs), capable of differentiating toward both the biliary and the hepatocyte lineages[1,2,3,4,5,6]. The niche microenvironment keeps the progenitor phenotype and inhibits cell differentiation. Several types of liver damage trigger the “ductular reaction”, in which specific alterations of the niche microenvironment promote the differentiation of HPCs toward a hepatocyte or cholangiocyte phenotype[4]. HPC activation is the first stage in progenitordependent regeneration, a comprehensive knowledge of the mechanisms by which HPCs start to proliferate and differentiate may be determinant to develop new therapies for liver disease

Objectives

Results

Conclusion