STAT3-mediated attenuation of CCl4-induced mouse liver fibrosis by the protein kinase inhibitor sorafenib
Introduction
Liver fibrosis is a significant health problem resulting from response of the liver to injury [1], [2]. Following injury, hepatocytes, biliary cells, Kupffer cells and T cells respond to create an inflammatory milieu [3], which stimulates hepatic stellate cells (HSCs) to transform from a quiescent vitamin A-storing cell lineage to an activated myofibroblast (α-SMA-expressing) and thereby acquires fibrogenic properties producing extracellular matrix proteins (ECM) [2], [4], [5], [6], [7], [8]. Other cell types also contribute to this pathological process and complex interplay amongst hepatic cell lineages occurs during fibrogenesis [3], [9]. Hepatocytes are the major targets in liver fibrosis [10]. Damaged hepatocytes release ROS as well as fibrogenic mediators and induce the recruitment of white blood cells by inflammatory cells. Apoptosis of damaged hepatocytes also stimulate the fibrogenic actions of liver myofibroblasts [11]. Thus, drugs which protect hepatocytes from injury are potentially treatment options for human liver fibrosis.
There are several pathways that can potentially be modulated to alter fibrosis. Amongst potential inhibitors is an oral multi-kinase inhibitor well known for its influence on tumor signaling and vasculature, coined Sorafenib (BAY43-9006, Nexavar) [12], [13], [14]. Signaling pathways affected by sorafenib include Raf, platelet-derived growth factor (PDGF), c-kit and vascular endothelial growth factor (VEGF). Sorafenib blocks receptor tyrosine kinase signaling (VEGFR, PDGFR, c-Kit and RET) and inhibits downstream Raf serine/threonine kinase activity to prevent tumor growth by antiangiogenic, antiproliferative and/or pro-apoptotic effects [15].
Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that regulates cell growth and survival by modulating the expression of many target genes [16]. Sorafenib has the potential to suppress STAT3 phosphorylation in human neoplasia [17], [18], [19]. However, due to the hepatoprotective and proliferative functions of STAT3, STAT3 in hepatocytes plays a protective role in preventing liver fibrosis [20], [21], [22], [23].
Recent data has shown a beneficial effect of sorafenib in patients with hepatocellular carcinoma (HCC) [12], [13], [14]. Other studies suggest that sorafenib attenuates the hypertensive syndrome in partial portal vein ligated rats [24], [25]. There are also data that note that sorafenib has antifibrotic activity, including in vitro effects of sorafenib on inhibition of activation, growth and collagen accumulation of HSC [26], [27]. Moreover, sorafenib influences paracrine signaling between HSCs and LECs and thereby regulates matrix and vascular changes associated with bile duct ligation-induced liver injury in rats [28]. In hepatocytes, in vitro experiments demonstrated that sorafenib suppresses TGF-β1-induced EMT [29]. In this study, we focused on the effect of sorafenib on cross talk between hepatocytes and Kupffer cells during liver fibrosis. We used CCl4 induced murine liver fibrosis model and three independent acute liver injury models to illustrate that sorafenib attenuates liver fibrosis and injury through up-regulation STAT3 phosphorylation in hepatocytes which dependent on Kupffer cell-derived IL-6.
Section snippets
Mice
C57BL/6 (B6) mice were purchased from the Experimental Animal Center, Chinese Academy of Science (Shanghai, China). Hepatocyte-specific signal transducer and activator of transcription 3 (STAT3) knockout (STAT3Hep−/−) mice (AlbCre+/− STAT3flox/flox) were provided by Dr. Xin-Yuan Fu. B6.129S6-Il6tm1Kopf (IL-6−/−) mice were purchased from JAX (Bar Harbor, Maine, USA). All mice were housed in a specific pathogen-free and controlled environment. All animal experiments conformed to the guidelines
Sorafenib attenuates CCl4-induced chronic liver injury and liver fibrosis
We first studied CCl4 induced chronic liver injury by injecting mice with CCl4 for 4 weeks and treating daily with sorafenib or control vehicle (Fig. 1A). As shown in Fig. 1B, ALT levels were significantly lower in sorafenib-treated mice compared to controls at 48 and 72 h (P < 0.001). Liver sections revealed less vacuolated cells (Fig. 1C) and significantly improved portal inflammation and hepatocellular degeneration in the sorafenib-treated mice compared to controls (P < 0.001) (Fig. 1D). The
Discussion
Liver fibrosis results from chronic damage to the liver in conjunction with the accumulation of ECM proteins, which is a characteristic of chronic liver diseases [1], [3]. Although experimental data has suggested targets that prevent fibrosis in rodents [8], the efficacy of most treatments has not been recapitulated in humans [3]. Sorafenib, the first oral multikinase inhibitor that blocks multiple signaling pathways, was initially approved as an oral agent for treating advanced renal cell
Conclusions
We found that sorafenib significantly attenuates CCl4-induced liver fibrosis and injury, with activated STAT3 playing a critical role in this therapeutic effect. And further study has proved that Kupffer cell-derived cytokine IL-6 is required for the sorafenib-mediated phosphorylation of STAT3. These results suggest that sorafenib is a potential therapeutic agent for liver fibrosis.
Conflict of interest
The authors have declared that no conflict of interest exists.
Acknowledgments
Financial support provided by the National Basic Research Program of China (973 Program-2010CB945300, 2013CB944900), the National Natural Science Foundation of China (30972738, 31021061, 81130058), and the Hundred Talents Program of the Chinese Academy of Sciences.
References (47)
- et al.
Smads 2 and 3 are differentially activated by transforming growth factor-beta (TGF-beta) in quiescent and activated hepatic stellate cells–constitutive nuclear localization of Smads in activated cells is TGF-beta-independent
J Biol Chem
(2003) - et al.
Targeted therapies for hepatocellular carcinoma
Gastroenterology
(2011) - et al.
Lack of glycoprotein 130/signal transducer and activator of transcription 3-mediated signaling in hepatocytes enhances chronic liver injury and fibrosis progression in a model of sclerosing cholangitis
Am J Pathol
(2010) - et al.
Signal transducer and activator of transcription 3 protects from liver injury and fibrosis in a mouse model of sclerosing cholangitis
Gastroenterology
(2010) - et al.
Sorafenib attenuates the portal hypertensive syndrome in partial portal vein ligated rats
J Hepatol
(2009) - et al.
New insights into the antifibrotic effects of sorafenib on hepatic stellate cells and liver fibrosis
J Hepatol
(2010) - et al.
Immune stimulation of hepatic fibrogenesis by CD8 cells and attenuation by transgenic interleukin-10 from hepatocytes
Gastroenterology
(2004) - et al.
Dendritic cell regulation of carbon tetrachloride-induced murine liver fibrosis regression
Hepatology
(2012) - et al.
Kupffer cell depletion by liposome-delivered drugs: comparative activity of intracellular clodronate, propamidine, and ethylenediaminetetraacetic acid
Hepatology
(1996) - et al.
Cell type-dependent pro- and anti-inflammatory role of signal transducer and activator of transcription 3 in alcoholic liver injury
Gastroenterology
(2008)
Biosynthesis and degradation of hyaluronan by nonparenchymal liver cells during liver regeneration
Hepatology
Efficacy and safety of sorafenib in patients in the Asia-Pacific region with advanced hepatocellular carcinoma: a phase III randomised, double-blind, placebo-controlled trial
Lancet Oncol
Neutrophil-derived superoxide anion induces lipid peroxidation and stimulates collagen synthesis in human hepatic stellate cells: role of nitric oxide
Hepatology
Human hepatic stellate cells show features of antigen-presenting cells and stimulate lymphocyte proliferation
Hepatology
Liver fibrosis–from bench to bedside
J Hepatol
Mechanisms of liver fibrosis
Clin Chim Acta
Liver fibrosis
J Clin Invest
Transcriptional regulation of hepatic stellate cell activation
Gut
Molecular mechanisms of hepatic fibrogenesis
J Gastroenterol Hepatol
The role and regulation of hepatic stellate cell apoptosis in reversal of liver fibrosis
Apoptosis
Hepatic stellate cells as a target for the treatment of liver fibrosis
Semin Liver Dis
Cooperation of liver cells in health and disease
Adv Anat Embryol Cell Biol
Mechanisms of liver injury: an overview
Curr Mol Med
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Both authors contributed equally to the manuscript.