%0 Journal Article
%T Retinoic acid generates a beneficial microenvironment for liver progenitor cell activation in acute liver failure.
%A Wang S
%A Link F
%A Munker S
%A Wang W
%A Feng R
%A Liebe R
%A Li Y
%A Yao Y
%A Liu H
%A Shao C
%A Ebert MPA
%A Ding H
%A Dooley S
%A Weng HL
%A Wang SS
%J Hepatol Commun
%V 8
%N 8
%D 2024 Aug 1
%M 39023343
%F 5.701
%R 10.1097/HC9.0000000000000483
%X <B>BACKGROUND: </B>When massive necrosis occurs in acute liver failure (ALF), rapid expansion of HSCs called liver progenitor cells (LPCs) in a process called ductular reaction is required for survival. The underlying mechanisms governing this process are not entirely known to date. In ALF, high levels of retinoic acid (RA), a molecule known for its pleiotropic roles in embryonic development, are secreted by activated HSCs. We hypothesized that RA plays a key role in ductular reaction during ALF.<BR><B>METHODS: </B>RNAseq was performed to identify molecular signaling pathways affected by all-trans retinoid acid (atRA) treatment in HepaRG LPCs. Functional assays were performed in HepaRG cells treated with atRA or cocultured with LX-2 cells and in the liver tissue of patients suffering from ALF.<BR><B>RESULTS: </B>Under ALF conditions, activated HSCs secreted RA, inducing RARα nuclear translocation in LPCs. RNAseq data and investigations in HepaRG cells revealed that atRA treatment activated the WNT-β-Catenin pathway, enhanced stemness genes (SOX9, AFP, and others), increased energy storage, and elevated the expression of ATP-binding cassette transporters in a RARα nuclear translocation-dependent manner. Further, atRA treatment-induced pathways were confirmed in a coculture system of HepaRG with LX-2 cells. Patients suffering from ALF who displayed RARα nuclear translocation in the LPCs had significantly better MELD scores than those without.<BR><B>CONCLUSIONS: </B>During ALF, RA secreted by activated HSCs promotes LPC activation, a prerequisite for subsequent LPC-mediated liver regeneration.