EGF Suppresses the Initiation and Drives the Reversion of TGF-ß1-induced Transition in Hepatic Oval Cells Showing the Plasticity of Progenitor Cells.

Transforming growth factor-ß1 (TGF-ß1) induces hepatic progenitors to tumor initiating cells through epithelial-mesenchymal transition (EMT), thus raising an important drawback for stem cell-based therapy. How to block and reverse TGF-ß1-induced transition is crucial for progenitors' clinical application and carcinogenic prevention. Rat adult hepatic progenitors, hepatic oval cells, experienced E-cadherin to N-cadherin switch and changed to α-smooth muscle actin (α-SMA) positive cells after TGF-ß1 incubation, indicating EMT. When TGF-ß1 plus EGF were co-administrated to these cells, EGF dose-dependently suppressed the cadherin switch and α-SMA expression. Interestingly, if EGF was applied to TGF-ß1-pretreated cells, the cells that have experienced EMT could return to their epithelial phenotype. Abruption of EGF receptor revealed that EGF exerted its blockage and reversal effects through phosphorylation of ERK1/2 and Akt. These findings suggest an important attribute of EGF on opposing and reversing TGF-ß1 effects, indicating the plasticity of hepatic progenitors.

Fibroblast Activation Protein Activates Macrophages and Promotes Parenchymal Liver Inflammation and Fibrosis.

BACKGROUND & AIMS: Fibroblast activation protein (FAP) is expressed on activated fibroblast. Its role in fibrosis and desmoplasia is controversial, and data on pharmacological FAP inhibition are lacking. We aimed to better define the role of FAP in liver fibrosis in vivo and in vitro. METHODS: FAP expression was analyzed in mice and patients with fibrotic liver diseases of various etiologies. Fibrotic mice received a specific FAP inhibitor (FAPi) at 2 doses orally for 2 weeks during parenchymal fibrosis progression (6 weeks of carbon tetrachloride) and regression (2 weeks off carbon tetrachloride), and with biliary fibrosis (Mdr2-/-). Recombinant FAP was added to (co-)cultures of hepatic stellate cells (HSC), fibroblasts, and macrophages. Fibrosis- and inflammation-related parameters were determined biochemically, by quantitative immunohistochemistry, polymerase chain reaction, and transcriptomics. RESULTS: FAP+ fibroblasts/HSCs were α-smooth muscle actin (α-SMA)-negative and located at interfaces of fibrotic septa next to macrophages in murine and human livers. In parenchymal fibrosis, FAPi reduced collagen area, liver collagen content, α-SMA+ myofibroblasts, M2-type macrophages, serum alanine transaminase and aspartate aminotransferase, key fibrogenesis-related transcripts, and increased hepatocyte proliferation 10-fold. During regression, FAP was suppressed, and FAPi was ineffective. FAPi less potently inhibited biliary fibrosis. In vitro, FAP small interfering RNA reduced HSC α-SMA expression and collagen production, and FAPi suppressed their activation and proliferation. Compared with untreated macrophages, FAPi regulated macrophage profibrogenic activation and transcriptome, and their conditioned medium attenuated HSC activation, which was increased with addition of recombinant FAP. CONCLUSIONS: Pharmacological FAP inhibition attenuates inflammation-predominant liver fibrosis. FAP is expressed on subsets of activated fibroblasts/HSC and promotes both macrophage and HSC profibrogenic activity in liver fibrosis.

Primary isolated hepatic oval cells maintain progenitor cell phenotypes after two-year prolonged cultivation.

BACKGROUND & AIMS: Although expandable hepatic progenitors provide renewable cell sources for treatment of hepatic disorders, long-term cultivation of hepatic progenitors may affect proliferation and differentiation abilities, and even initiate the formation of malignant cancer stem cells. This study aims to determine characteristics of primary cultured hepatic oval cells after prolonged cultivation in vitro. METHODS: Hepatic oval cells isolated from rats fed with a choline-deficient, ethionine-supplemented diet were continuously propagated every 5-7 days, to 100 passages over two years. Hepatocytic differentiation was induced by sodium butyrate and characterized using western blot, periodic acid Schiff assays, albumin secretion and urea production. Proliferation capacity was evaluated using growth-curve and cell-cycle analysis; anchorage-independent growth and tumorigenicity were determined using soft agar and xenograft assay. RESULTS: After 2 years of serial passages, hepatic oval cells with typical epithelial morphology continuously expressed OV-6, BD-1, BD-2, and Dlk as markers for hepatic progenitors, cytokeratin 19 as a cholangiocyte marker, and alpha-fetoprotein and albumin as hepatocyte markers. Furthermore, sodium butyrate could induce these cells to become glycogen-storage cells with the functions of albumin secretion and ureagenesis from ammonia clearance, indicating hepatocytic differentiation. Although proliferation slightly accelerated after the 50th passage, hepatic oval cells stayed diploid cells with features of chromosomal stability, which did not acquire anchorage-independent growth capacity and caused no tumor in immunodeficient mice, suggesting no spontaneous malignant transformation. CONCLUSIONS: Hepatic oval cells retain the progenitor cell features without spontaneous malignant transformation after prolonged cultivation, and thus may serve as an expandable cell source for future exploitation of stem cell technology.

Liver fibrosis: Direct antifibrotic agents and targeted therapies.

Liver fibrosis and in particular cirrhosis are the major causes of morbidity and mortality of patients with chronic liver disease. Their prevention or reversal have become major endpoints in clinical trials with novel liver specific drugs. Remarkable progress has been made with therapies that efficiently address the cause of the underlying liver disease, as in chronic hepatitis B and C. Highly effective antiviral therapy can prevent progression or even induce reversal in the majority of patients, but such treatment remains elusive for the majority of liver patients with advanced alcoholic or nonalcoholic steatohepatitis, genetic or autoimmune liver diseases. Moreover, drugs that would speed up fibrosis reversal are needed for patients with cirrhosis, since even with effective causal therapy reversal is slow or the disease may further progress. Therefore, highly efficient and specific antifibrotic agents are needed that can address advanced fibrosis, i.e., the detrimental downstream result of all chronic liver diseases. This review discusses targeted antifibrotic therapies that address molecules and mechanisms that are central to fibrogenesis or fibrolysis, including strategies that allow targeting of activated hepatic stellate cells and myofibroblasts and other fibrogenic effector cells. Focus is on collagen synthesis, integrins and cells and mechanisms specific including specific downregulation of TGFbeta signaling, major extracellular matrix (ECM) components, ECM-crosslinking, and ECM-receptors such as integrins and discoidin domain receptors, ECM-crosslinking and methods for targeted delivery of small interfering RNA, antisense oligonucleotides and small molecules to increase potency and reduce side effects. With an increased understanding of the biology of the ECM and liver fibrosis and an improved preclinical validation, the translation of these approaches to the clinic is currently ongoing. Application to patients with liver fibrosis and a personalized treatment is tightly linked to the development of noninvasive biomarkers of fibrosis, fibrogenesis and fibrolysis.

TGF-ß1 Induces the Dual Regulation of Hepatic Progenitor Cells with Both Anti- and Proliver Fibrosis.

Transforming growth factor-beta 1 (TGF-ß1) plays a central role in hepatic progenitor cells- (HPCs-) mediated liver repair and fibrosis. However, different effects of TGF-ß1 on progenitor cells have not been described. In this study, both in vitro (HPCs cocultured with hepatic stellate cells (HSCs) in transwells) and in vivo (CCl4-injured liver fibrosis rat) systems were used to evaluate the impacts. We found that HPCs pretreated with TGF-ß1 for 12 hours inhibited the activation of HSCs, while sensitization for 48 hours increased the activation of HSCs. Consistent with these in vitro results, the in vivo fibrosis rat model showed the same time-dependent dual effect of TGF-ß1. Regression of liver fibrosis as well as normalization of serum aminotransferase and albumin levels was detected in the rats transplanted with HPCs pretreated with TGF-ß1 for 12 hours. In contrast, severe liver fibrosis and elevated collagen-1 levels were detected in the rats transplanted with HPCs pretreated with TGF-ß1 for 48 hours. Furthermore, the TGF-ß1-pretreated HPCs were shown to deactivate HSCs via enhancing SERPINE1 expression. Inhibition of SERPINE1 reversed the deactivation response in a dose-dependent manner.

Baseline Hepatitis B Virus DNA Level is a Promising Factor for Predicting the 3 (rd) Month Virological Response to Entecavir Therapy: A Study of Strict Defined Hepatitis B virus Induced Cirrhosis.

BACKGROUND: Cirrhosis is a common complication of chronic hepatitis B. It remains unclear if viral and biochemical parameters at baseline affect virological response to entecavir and therefore warrant investigation. In the present study, we aimed to evaluate the efficacy of entecavir therapy by monitoring virological response at the end of the 3 rd month of treatment and try to figure out whether baseline factors could help predict it in a cohort of hepatitis B virus (HBV) compensated cirrhosis patients and to determine the cut-off value of a predicting parameter. METHODS: A total of 91 nucleos(t)ide-naïve patients with HBV induced cirrhosis (compensatory stage) were enrolled in a prospective cohort. HBV DNA and alanine aminotransferase (ALT) were tested at baseline and monitored every 3-6 months after starting therapy. RESULTS: Of all 91 patients, the median follow-up time was 12 (9-24) months. Overall, 64 patients (70.3%) achieved virological response in the 3 rd month. Univariate analysis showed that the 3 rd month virological response can be predicted by baseline HBV DNA levels (P < 0.001, odds ratio [OR]: 2.13, 95% confidence interval [CI]: 1.44-3.15), ALT value (P = 0.023, OR: 1.01, 95% CI: 1.00-1.01) and hepatitis B e antigen (HBeAg) negativity (P = 0.016, OR: 0.30, 95% CI: 0.11-0.80). Multiple regression analysis showed baseline HBV DNA level was the only parameter related to full virological response. Higher baseline HBV DNA strata indicated a higher probability that HBV DNA remains detectable at the 3 rd month (P = 0.001). Area under receiver operating characteristic curve for determining the 3 rd month virological response by baseline HBV DNA was 77.6% (95% CI: 66.7-85.2%), with a best cut-off value of 5.8 log 10 . CONCLUSIONS: Baseline HBV DNA, HBeAg negativity, and ALT were independent factors contributing to virological response at the 3 rd month. Further, multiple regression showed that HBV DNA level was the only parameter predicting full virological response as early as the 3 rd month, in this cirrhosis cohort.

Increasing newly diagnosed rate and changing risk factors of HCV in Yanbian Prefecture, a high endemic area in China.

BACKGROUND: The newly diagnosed rate of HCV infection is increasing in China. However, the risk factors have not been fully identified. Here, a survey was performed in Yanbian Prefecture, a high-endemic area in China. METHODS: We identified newly diagnosed HCV infection in 2007-2011, using the local National Disease Supervision Information Management System from the Chinese Center for Disease Control and Prevention. We determined the risk factors using a case-control survey by questionnaire. RESULTS: Yanbian Prefecture had a rapid increase in the yearly newly diagnosed rate of HCV infection from 32.6 to 72.1/100.000 from the year 2007 to 2011. People aged 50-64 years had a high HCV infection of 43.4%, but only 0.3% of cases were reported in those aged less than 20 years. Cosmetic treatment, family history, blood transfusion, and dental treatment were independent risk factors for HCV infection. Unexpectedly, cosmetic treatments [odd ratio (OR) = 5.15, 95% confidence interval (CI) = 2.31-11.48, P = 0.00] and family history (OR = 4.68, 95% CI = 2.67-8.75, P = 0.00) showed a higher risk than the conventional risk factors of blood transfusion (OR = 4.49, 95% CI = 1.95-10.37, P = 0.001) and dental treatment (OR = 2.98, 95% CI = 1.42-6.25, P = 0.00). To further analyze the intrafamilial transmission, we found that spouses of HCV patients had an increased risk for acquiring HCV (OR = 5.75, 95% CI: 1.94-17.07), without significant association between either HCV RNA viral load (P = 0.29) or genotype (P = 0.43). CONCLUSIONS: HCV infection was increased in Yanbian Prefecture. Cosmetic treatment was a higher risk factor than medical procedure. HCV infection had a clear family clustering phenomenon, especially between spouses.

Connective tissue growth factor induces hepatic progenitor cells to differentiate into hepatocytes.

Connective tissue growth factor (CTGF) plays an important role in the proliferation of hepatic progenitors, however, little is known concerning the mechanism(s) through which it influences their differentiation. The differentiation of hepatic progenitors (WB-F344), either stimulated with recombinant CTGF or stably transfected with a CTGF overexpression plasmid, was investigated. Expression of the differentiation markers α-fetoprotein (AFP), albumin (ALB) and cytokeratin-19 (CK-19) was assessed. To confirm the effects of CTGF on progenitor differentiation, cells were treated with an inhibitor (WP631) of CTGF. Treatment of WB-F344 cells with recombinant CTGF for 24 h did not change the survival rate significantly, but the progenitors were enlarged with a decreased nuclear/cytoplasmic ratio. CTGF downregulated the expression of the fetal hepatocyte marker, AFP, while it upregulated the mature hepatocyte cell marker, ALB. The effect of CTGF overexpression plasmid on WB-F344 cell differentiation was consistent with a pattern of direct CTGF stimulation, including decreased AFP and increased ALB expression. Furthermore, the suppression of CTGF induction by an inhibitor was associated with significant inhibition of hepatic progenitor cell differentiation into hepatocytes. Importantly, we showed that differentiated WB-F344 cells by CTGF had in vitro functions characteristic of hepatocytes, including ALB production, glycogen storage and cytochrome P450 activity. Both recombinant CTGF and the CTGF overexpression plasmid induced hepatic progenitor differentiation into hepatocytes. This was suppressed by the CTGF inhibitor.