Z Gastroenterol 2011; 49 - P456
DOI: 10.1055/s-0031-1285727

Tracking genetic variation underlying differenzial reaction to TGF-beta signalling in inbred mouse strains

R Müllenbach 1, I Ilkavets 2, S Dooley 3, F Lammert 4
  • 1Universitätsklinikum des Saarlandes, Klinik für Innere Medizin II, Homburg, Germany
  • 2Uniklinik Heidelberg, Mannheim, Germany
  • 3Universität Heidelberg, Mannheim, Germany
  • 4Universitätsklinikum Saarland, Homburg, Germany

Background: TGF-β is the central pro-fibrogenic cytokine in the liver. In hepatocytes, cell death by apoptosis, growth arrest by cellular senescence or contribution towards healing by epithelial-mesenchymal transition are possible outcomes. We speculate that genetic differences underlying differences in response to TGF-β signalling may be involved in predisposition to fibrosis or hepatocellular carcinoma.

Aims: Our aim is to identify differences in the transcriptional response of hepatocytes from genetically distinct inbred mouse strains to TGF-β signalling.

Methods: We characterised the transcriptional response of primary mouse hepatocytes from strains C57BL/6J and DBA/2J in vitro after stimulation with 5ng/ml TGF-β for 0, 1, 6, 24 and 48 hours using Affymetrix array Mm430_2.0 (45.000 probes) and compared the changes.

Results: In total, 2400 genes showed a difference of at least 2-fold with P<10E-6 in comparison to basal. Overall, 1100 genes showed expression differences of at least 2-fold with P<10E-6 between TGF-β treated and non-treated samples at 1, 6, 24 or 48 hours. Geneset enrichment analysis (GSEA) of differences between treated and untreated cells revealed particularly marked differences between both strains in DNA and RNA processing and repair, DNA metabolic processes and mitochondrial activity at 1h. At this point in time, the most profound differences in response to TGF-β were seen in the following genes: [DBA>C57BL6] nuclear receptor 0B2 (NrOb2), apolipoprotein A-V (ApoA5), early growth response 1 (Egr1), activating transcription factor 3 (Atf3), inhibitor of DNA binding 2 (Id2), Fos; [C57BL/6J>DBA] F0/G1 switch Gene 2 (G0s2), DNA-damage inducible transcript 4 (Ddit4), Adp-ribosylation factor-like 4d (Arl4d), chemokine (C-X-C) motif ligand 1 (Cxcl1), Krüppel-like faktor 10 (Klf10), glucose-6-phospatase, catalytic (G6PC), claudin 4 (cldn4).

Conclusions: Transcriptional profiling in cultured hepatocytes from different inbred laboratory mouse strains reveals profound differences in response to TGF-β stimulation. These changes are likely to correlate with variations in regulatory sequences. Cxcl1 and Fos are part of the senescence-associated secretory phenotype, which is known to modulate pro-fibrogenic pathways.