Z Gastroenterol 2015; 53 - A1_37
DOI: 10.1055/s-0034-1397078

Mouse hepatic stellate cells are responsive to LPS and contribute to the acute phase response of hepatocytes

R Liebe 1, K Breitkopf-Heinlein 1, K Waldow 2, S Braun 2, M Thomas 3, F Schildberg 4, P Knolle 4, U Zanger 3, U Klingmüller 2, M Ebert 1, S Dooley 1
  • 1University of Heidelberg, Department of Medicine II; Section Molecular Hepatology – Alcohol Associated Diseases; Medical Faculty Mannheim, Mannheim, Germany
  • 2University of Heidelberg, Systems Biology of Signal Transduction (B200) DKFZ, Heidelberg, Germany
  • 3University of Stuttgart, Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany
  • 4University of Bonn, Institute of Molecular Medicine and Experimental Immunology, Bonn, Germany

Background: The acute phase response (APR) is a systemic inflammatory condition initiated by activated phagocytic cells, fibroblasts and endothelial cells to prevent tissue damage and initiate repair processes.

The aim of our study was to quantify the contribution of hepatic stellate cells (HSC) towards the APR induction. To this end, we quantified the secretory output of HSC with respect to the main acute phase cytokines. Hepatocytes' response to the secretory HSC output was analysed by Fluidigm real time PCR analysis.

Methodology: Primary HSC were cultivated for 48 hours before adding LPS to the medium. The release of 23 cytokines and chemokines was analysed by Luminex cytokine array technology after 24 hours of LPS stimulation (50 ng/ml). The main acute phase cytokines IL6, IL1-beta and TNF-alpha were quantified after 2, 6 and 24 hours of LPS stimulation (0/10/50/100 ng/ml).

Tissue culture supernatant of HSC following 24 hours stimulation with 100 ng/ml LPS was used to stimulate primary hepatocytes for 24 hours. Expression of 48 acute phase proteins (APP) in hepatocytes was analysed by Fluidigm real time PCR analysis and compared to hepatocytes treated with LPS or IL6 only for 6, 12 or 24 hours.

Results: In HSC, G-CSF, KC (Cxcl1), IL-12 (p70), MCP-1a (Ccl2), TNFα and MIP1a (Ccl3) were the most prominently and significantly upregulated secreted cytokines after 24 hours and transcription of Ccls -2, -3, -4, -5 and -7, as well as Cxcls -1, -2, -3 and -5 were upregulated by LPS together with IL1b, IL6 and TNFα in HSC. Stimulation of hepatocytes with conditioned medium from LPS-treated HSC led to increased mRNA levels of Saa1, Saa2 and Orm1. Other targets like Hepcidin, Saa3 and IL-33 were already upregulated by direct treatment with LPS alone.

Conclusion: Cytokine secretion data from HSC and expression data from hepatocytes exposed to HSC supernatant show a specific and intriguing role for HSC during the orchestration of the acute phase response following endotoxemia. Besides being amplifiers of macrophage-induced cytokine signalling, these cells produce an independent secretory profile with an impact on hepatocytes that is different from effects induced by IL6 or LPS only.

Corresponding author: Breitkopf-Heinlein, Katja

E-Mail: katja.breitkopf@medma.uni-heidelberg.de