Transcriptional regulation by NR5A2 couples cell differentiation

Tissue-specific differentiation and inflammatory programmes are thought to independently contribute to disease. The orphan nuclear receptor NR5A2 is a key regulator of pancreas differentiation, and SNPs in and near the human gene are associated with risk of pancreatic cancer. In mice, Nr5a2 heterozygosity sensitizes the pancreas to damage, impairs regeneration, and cooperates with mutant Kras in tumor progression. Through transcriptomic analysis, we uncovered a basal pre-inflammatory state in the pancreas of heterozygous mice that is reminiscent of pancreatitis-induced inflammation and is conserved in histologically normal human pancreata with reduced Nr5a2 mRNA expression. In mice, Nr5a2 undergoes a dramatic transcriptional switch from tissue-specific to inflammatory loci, which promotes AP-1-dependent inflammatory gene transcription. Deletion of c-Jun in the pancreas of Nr5a2+/- mice rescues the pre-inflammatory phenotype and the defective regenerative response to damage. These findings provide compelling evidence that the same transcriptional networks supporting homeostasis in normal tissue can be subverted to foster inflammation upon genetic or environmental constraints. Overall design: A mild acute pancreatitis was induced by seven hourly injections of the CCK analog caerulein (Bachem) at 50 ug/kg. Briefly, animals were weighted before the beginning of the procedure and caerulein was administered i.p. Mice were sacrificed by cervical dislocation 8h, 24h,and 48h after the first injection. Three animals of each genotype and timepoint were analysed.