Z Gastroenterol 2016; 54(12): 1343-1404
DOI: 10.1055/s-0036-1597362
1. Fibrogenesis
Georg Thieme Verlag KG Stuttgart · New York

Generation and functional analyses of hepatocyte-specific type I interleukin-1 receptor (IL-1RI) knockout mice

N Gehrke
1   Johannes Gutenberg University, I. Department of Medicine, University Medical Center, Mainz, Germany
,
N Hövelmeyer
2   Johannes Gutenberg University, Institute of Molecular Medicine, University Medical Center, Mainz, Germany
,
A Waisman
2   Johannes Gutenberg University, Institute of Molecular Medicine, University Medical Center, Mainz, Germany
,
PR Galle
1   Johannes Gutenberg University, I. Department of Medicine, University Medical Center, Mainz, Germany
,
JM Schattenberg
1   Johannes Gutenberg University, I. Department of Medicine, University Medical Center, Mainz, Germany
› Author Affiliations
Further Information

Publication History

Publication Date:
19 December 2016 (online)

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Background: IL-1-type cytokines including IL-1α, IL-1β and IL-1Ra are among the most potent molecules of the innate immune system and exert their biological function through the ubiquitously expressed IL-1RI. The role of IL-1RI has been studied in myeloid-derived cells, fibroblast and endothelium, however its role in hepatocytes during acute and chronic liver disease remains to be determined.

Methods: Using the Cre/loxP system, we generated a mouse that lacks IL-1RI specifically in hepatocytes. Hepatocyte-specific deletion of IL-1RI was achieved by crossing IL-1RIflox/flox mice, in which exon 5 of the Il1r1 gene is flanked by loxP sites, with mice expressing Cre-recombinase under an albumin promoter generating new albumin-cre:IL-1RIflox/flox (IL-1RIHep-/-) mice.

Results: IL-1RIHep-/- mice appeared healthy, had normal ALT and AST levels and normal liver histology at 6 months of age. No metabolic or liver-specific phenotypes were observed at this age. IL-1RIHep-/- mice exhibited a significant > 99% reduction of Il1r1 mRNA expression in primary hepatocytes compared to wild type (wt) hepatocytes. Expression levels of Il1a and Il1b mRNA were also significantly reduced (14.7% and 9.1%). To examine the functional effect of IL-1RI deletion, in vitro stimulation of IL-1RIHep-/- hepatocytes with recombinant mouse IL-1α protein (10 ng/ml) was performed, which did not lead to an upregulation of Il1r1 mRNA in IL-1RIHep-/- hepatocytes, whereas wt hepatocytes exhibited a 1.8-fold induction of Il1r1 mRNA. Also the mRNA expression of the target genes Il1b, Il6 and Ccl2 was induced only in wt hepatocytes following stimulation with recombinant mouse IL-1α. However, in response to LPS (10 µg/ml) we detected an upregulated expression of Il1a, Il1b, Il6 and Ccl2 mRNA irrespective of the genotype, although the absolute expression levels in IL-1RIHep-/- hepatocytes were below the levels in the wt. Il1r1 mRNA was again only 1.8-fold upregulated in wt hepatocytes.

Conclusion: This novel IL-1RIHep-/- mouse model exhibits a functional deletion with loss of signaling through IL1-RI in hepatocytes and allows to further investigate this signaling pathway in acute and chronic liver disease.