Liver Receptor Homolog-1 (LRH-1/NR5A2) orchestrates hepatic inflammation and TNF-induced cell death
Liver Receptor Homolog-1 (LRH-1/NR5A2) is a nuclear receptor that has been shown to promote apoptosis resistance in various tissues and disease contexts, however, its role in liver cell death remains unexplored. Deletion of LRH-1 in hepatocytes developed into a mild steatosis and inflammation already under steady-state conditions. Unexpectedly, hepatocyte-specific deletion of LRH-1 also resulted in a profound protection of mice from TNF-induced hepatocyte apoptosis and associated hepatitis. LRH-1-deficient hepatocytes showed elevated NF-B activity, while LRH-1 overexpression inhibited NF-B activity. This inhibition was based on direct physical interaction of the ligand-binding domain of LRH-1 and the Rel homology domain of NF-B subunit RelA. Mechanistically, we found that increased transcription of anti-apoptotic NF-B target genes, together with proteasomal degradation of pro-apoptotic BIM via regeneration-driven EGF receptor signaling, prevented mitochondrial apoptosis, ultimately protecting mice from TNF-induced liver damage. Collectively, our study demonstrates that LRH-1 is a critical modulator of cell death and inflammation in the healthy and diseased liver. HighlightsO_LIHepatic LRH-1 deletion causes mild liver steatosis, fibrosis, and inflammation. C_LIO_LIFemale LRH-1-deficient mice are protected from TNF-induced liver damage. C_LIO_LILRH-1 interacts with NF-B and inhibits its activity. C_LIO_LILRH-1 deletion-provoked inflammation causes degradation of pro-apoptotic protein BIM. C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=125 SRC="FIGDIR/small/542039v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@13cd609org.highwire.dtl.DTLVardef@1080012org.highwire.dtl.DTLVardef@3cd9c4org.highwire.dtl.DTLVardef@fd0438_HPS_FORMAT_FIGEXP M_FIG C_FIG