Macrophage secretory products induce an inflammatory phenotype in hepatocytes
Date
2012
Authors
Melino, M.
Gadd, V.L.
Walker, G.V.
Skoien, R.
Barrie, H.D.
Jothimani, D.
Horsfall, L.
Jones, A.
Sweet, M.J.
Thomas, G.P.
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Journal article
Citation
World Journal of Gastroenterology, 2012; 18(15):1732-1744
Statement of Responsibility
Michelle Melino, Victoria L Gadd, Gene V Walker, Richard Skoien, Helen D Barrie, Dinesh Jothimani, Leigh Horsfall, Alun Jones, Matthew J Sweet, Gethin P Thomas, Andrew D Clouston, Julie R Jonsson, Elizabeth E Powell
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Abstract
Aim: To investigate the influence of macrophages on hepatocyte phenotype and function.
Methods: Macrophages were differentiated from THP-1 monocytes via phorbol myristate acetate stimulation and the effects of monocyte or macrophage-conditioned medium on HepG2 mRNA and protein expression determined. The in vivo relevance of these findings was confirmed using liver biopsies from 147 patients with hepatitis C virus (HCV) infection.
Results: Conditioned media from macrophages, but not monocytes, induced a transient morphological change in hepatocytes associated with upregulation of vimentin (7.8 +/- 2.5-fold, P = 0.045) and transforming growth factor (TGF)-beta 1 (2.6 +/- 0.2-fold, P < 0.001) and downregulation of epithelial cadherin (1.7 +/- 0.02-fold, P = 0.017) mRNA expression. Microarray analysis revealed significant upregulation of lipocalin-2 (17-fold, P < 0.001) and pathways associated with inflammation, and substantial downregulation of pathways related to hepatocyte function. In patients with chronic HCV, real-time polymerase chain reaction and immunohistochemistry confirmed an increase in lipocalin-2 mRNA (F0 1.0 +/- 0.3, F1 2.2 +/- 0.2, F2 3.0 +/- 9.3, F3/4 4.0 +/- 0.8, P = 0.003) and protein expression (F1 1.0 +/- 0.5, F2 1.3 +/- 0.4, F3/4 3.6 +/- 0.4, P = 0.014) with increasing liver injury. High performance liquid chromatography-tandem mass spectrometry analysis identified elevated levels of matrix metalloproteinase (MMP)-9 in macrophage-conditioned medium, and a chemical inhibitor of MMP-9 attenuated the change in morphology and mRNA expression of TGF-beta 1 (2.9 +/- 0.2 vs 1.04 +/- 0.1, P < 0.001) in macrophage-conditioned media treated HepG2 cells. In patients with chronic HCV infection, hepatic mRNA expression of CD163 (F0 1.0 +/- 0.2, F1/2 2.8 +/- 0.3, F3/4 5.3 +/- 1.0, P = 0.001) and MMP-9 (F0 1.0 +/- 0.4, F1/2 2.8 +/- 0.3, F3/4 4.1 +/- 0.8, P = 0.011) was significantly associated with increasing stage of fibrosis.
Conclusion: Secreted macrophage products alter the phenotype and function of hepatocytes, with increased expression of inflammatory mediators, suggesting that hepatocytes actively participate in liver injury
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Copyright 2012 The author(s) 1995-2020. Published by Baishideng Publishing Group Inc. All rights reserved. Articles published by this open-access journal are distributed under the terms of the Creative Commons Attribution-Noncommercial (CC BY-NC 4.0) License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. (https://creativecommons.org/licenses/by-nc/4.0/)