摘要
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 macrophageconditioned 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)-β1(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,realtime 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 macrophageconditioned medium,and a chemical inhibitor of MMP-9 attenuated the change in morphology and mRNA expression of TGF-β1(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.
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 macrophageconditioned 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）-β1（2.6±0.2-fold,P0.001）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,realtime 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 macrophageconditioned medium,and a chemical inhibitor of MMP-9 attenuated the change in morphology and mRNA expression of TGF-β1（2.9±0.2 vs 1.04±0.1,P0.001） 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.
基金
Supported by The National Health and Medical Research Council of Australia,No.APP1003108
the Queensland Government’s Smart State Health and Medical Research Fund
The Princess Alexandra Hospital Research and Development Foundation
The Sasakawa Foundation(Royal Children’s Hospital,Brisbane)
an Unrestricted Education Grant from MSD(to Powell EE)
a Lions Medical Research Foundation Senior Research Fellowship(to Thomas GP)
