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Hepatic fibrosis occurs during the progression of primary sclerosing cholangitis (PSC) and is characterized by accumulation of extracellular matrix proteins. Proliferating cholangiocytes and activated hepatic stellate cells (HSCs) participate in the promotion of liver fibrosis during cholestasis. Gonadotropin-releasing hormone (GnRH) is a trophic peptide hormone synthesized by hypothalamic neurons and the biliary epithelium and exerts its biological effects on cholangiocytes by interaction with the receptor subtype (GnRHR 1 ) expressed by cholangiocytes and HSCs. Previously, we demonstrated that administration of GnRH to normal rats increased intrahepatic biliary mass (IBDM) and hepatic fibrosis. Also, miR-200b is associated with the progression of hepatic fibrosis; however, the role of the GnRH/GnRHR 1 /miR-200b axis in the development of hepatic fibrosis in PSC is unknown. Herein, using the mouse model of PSC (multidrug resistance gene 2 knockout), the hepatic knockdown of GnRH decreased IBDM and liver fibrosis. In vivo and in vitro administration of GnRH increased the expression of miR-200b and fibrosis markers. The GnRH/GnRHR 1 axis and miR-200b were up-regulated in human PSC samples. Cetrorelix, a GnRHR 1 antagonist, inhibited the expression of fibrotic genes in vitro and decreased IBDM and hepatic fibrosis in vivo . Inhibition of miR-200b decreased the expression of fibrosis genes in vitro in cholangiocyte and HSC lines. Targeting the GnRH/GnRHR 1 /miR-200b axis may be key for the management of hepatic fibrosis during the progression of PSC.

Cellular senescence is a state of irreversible cell cycle arrest that has been involved in many gastrointestinal diseases, including human cholestatic liver disorders. Senescence may play a role in biliary atresia, primary sclerosing cholangitis, cellular rejection, and primary biliary cirrhosis, four liver diseases affecting cholangiocytes and the biliary system. In this review, we examine proposed mechanisms of senescence-related biliary diseases, including hypotheses associated with the senescence-associated phenotype, induction of senescence in nearby cells, and the depletion of stem cell subpopulations. Current evidence for the molecular mechanisms of senescence in the previously mentioned diseases is discussed in detail, with attention to recent advances on the role of pathways associated with senescence-associated phenotype, stress-induced senescence, telomere dysfunction, and autophagy.

IL-6/Stat3 is associated with the regulation of transcription of key cellular regulatory genes (microRNAs) during different types of liver injury. This study evaluated the role of IL-6/Stat3 in regulating miRNA and miR-21 in alcoholic liver disease. By microarray, we identified that ethanol feeding significantly up-regulated 0.8% of known microRNAs in mouse liver compared with controls, including miR-21. Similarly, the treatment of normal human hepatocytes (N-Heps) and hepatic stellate cells (HSCs) with ethanol and IL-6 significantly increased miR-21 expression. Overexpression of miR-21 decreased ethanol-induced apoptosis in both N-Heps and HSCs. The expression level of miR-21 was significantly increased after Stat3 activation in N-Heps and HSCs, in support of the concept that the 5'-promoter region of miR-21 is regulated by Stat3. Using real time PCR, we confirmed that miR-21 activation is associated with ethanol-linked Stat3 binding of the miR-21 promoter. A combination of bioinformatics, PCR array, dual-luciferase reporter assay, and Western blot analysis revealed that Fas ligand (TNF superfamily, member 6) (FASLG) and death receptor 5 (DR5) are the direct targets of miR-21. Furthermore, inhibition of miR-21 by specific Vivo-Morpholino and knock-out of IL-6 in ethanol-treated mice also increased the expression of DR5 and FASLG in vivo during alcoholic liver injury. The identification of miR-21 as an important regulator of hepatic cell survival, transformation, and remodeling in vitro, as well as its upstream modulators and downstream targets, will provide insight into the involvement of altered miRNA expression in contributing to alcoholic liver disease progression and testing novel therapeutic approaches for human alcoholic liver diseases.

Alcoholic liver disease affects a great number of people worldwide. With limited therapeutic options, stem cell therapy offers significant potential for these patients. To date, a limited number of clinical trials have produced transient clinical responses to cell therapy in patients with alcoholic liver disease. Stem cell therapy to reorganize the postnatal liver is an important theme and mission for patients with chronic liver disorders including alcoholic liver injury. We therefore should redevelop the evidence of cell-based liver regeneration therapy, focusing on targets (disease, patient's status and hepatic function), materials (cells, cytokines and genes), and methodology (stem cell types and their derived microparticles, transplantation route, implantation technology and tissue engineering). In this review, we summarize the recent findings regarding the experimental and clinical use of mesenchymal and liver stem cells, focusing mainly on the treatment of alcoholic liver disorders and their relevance in the field of regenerative medicine, and advances on the role of microvesicles and exosomes in this process. We discuss new advances in stem cell therapy from liver regeneration to liver re-organization, which is involved in the recent progress of on-going clinical trials, basic research in stem cell therapy and liver regeneration, and updated exosomes/microvesicles recovery/repairing technology.

A S L D A b st ra ct s GDNF suppresses expression of genes associated with hepatic steatosis Real-time PCR analyses of gene expression in liver from WT and GDNF Tg mice maintained on RD or HFD for 12 weeks. Plotted are means + SEM. *, P 5 mice per group.

A S L D A b st ra ct s increase in circulating Galanin in the serum. Galanin immunoreactivity was observed in both cholangiocytes and hepatocytes, whereas GalR1 was found predominantly in cholangiocytes. Systemic treatment of rats with M617 increased both CK-19 expression and IBDM in both sham and BDL-treated animals. In vitro, treatment of the mouse cholangiocyte cell line with M617 increased ERK1/2 and RSK-1 activity. There was a concomitant increase in cholangiocyte proliferation after M617 treatment that could be blocked by pretreatment with inhibitors for ERK1/2 and RSK-1. Conclusions: Data presented here demonstrate a direct stimulatory role for Galanin on cholangiocyte proliferation under physiological (sham) and pathological (BDL) conditions via a mechanism involving the activation of ERK1/2 and subsequent phosphorylation of RSK-1. Targeting Galanin or GalR1 may prove a useful strategy to regulate biliary mass during cholestatic liver injury.

Background & aims: Disruption of circadian rhythm is associated with cancer development and progression. MicroRNAs (miRNAs) are a class of small noncoding RNAs that trigger mRNA translation, repression or degradation. Core clock genes are the molecular basis of circadian rhythms, which include BMAL1, CLOCK, Per1/2/3 and Cry1/2. We have previously demonstrated the downregulation of Per1 expression in human cholangiocarcinoma (CCA) that was predicted as the direct target of miR-34a. Thus, we aimed to evaluate the role of deregulated circadian rhythm and related microRNAs in CCA growth. Methods: Human intraand extrahepatic CCA cells and non-malignant (H69) human cholangiocytes were serum starved for 48 hr before stimulation with 50% serum for 2 hours. The 24-hour rhythmic expression of core clock genes, such as Per1,2/3, CLOCK, BMAL1 and Cry1/2 was evaluated in CCA and H69 cells by real-time PCR. To further evaluate the role of Per1, we overexpressed Per1 by transfecting the Mz-ChA-1 cells with Per1 cDNA and empty vector. In parallel, we also silenced miR-34a expression with lenti-miR-34a ZIP with relative controls. A stably overexpressing Per1 cell line and silencing of miR-34a were established, respectively. Then, wemeasured: (i) cell proliferation byMTS assays and PCNA immunoblots; (ii) cell cycle by BD Cycle test Plus reagent kit; (iii) apoptosis by Annexin V-PE apoptosis detection kit; and (iv) cell migration and invasion by commercially available kits. We utilized luciferase assay to demonstrate that Per1 act as a target of miR-34a. Results: The 24-hour rhythmical expression of Per1 was abolished in all CCA cell lines but not in H69 cells. The rhythmic expression of BMAL1, CLOCK, Per2/3, Cry1/2 was also lost in some of the CCA cell lines tested. After overexpression of Per1, the extrahepatic CCA cell line, Mz-ChA-1, showed: (i) reduced cell proliferation (by MTS assays and PCNA immunoblots); (ii) higher G0/G1 arrest and lower G2/M arrest; (iii) enhanced apoptosis; and (iv) decreased cell invasion and migration compared to control cells. Interestingly, miR-34a was rhythmically expressed in CCA cell lines and H69. The expression level of miR-34a was higher in CCA cell lines compared to H69. Moreover, the inhibition of miR-34a decreased proliferation, migration and invasion in CCA cell lines. Dual luciferase reporter assay demonstrated that miR-34a directly targets Per1. Summary and conclusions: Disruption of circadian rhythms, miR-34a and Per1 expression may contribute to the malignant phenotypes of human cholangiocarcinoma. Our findings suggest that modulation of miR-34a-dependent Per1 expression may represent a novel therapeutic approach for human CCA.

A S L D A b st ra ct s increase in circulating Galanin in the serum. Galanin immunoreactivity was observed in both cholangiocytes and hepatocytes, whereas GalR1 was found predominantly in cholangiocytes. Systemic treatment of rats with M617 increased both CK-19 expression and IBDM in both sham and BDL-treated animals. In vitro, treatment of the mouse cholangiocyte cell line with M617 increased ERK1/2 and RSK-1 activity. There was a concomitant increase in cholangiocyte proliferation after M617 treatment that could be blocked by pretreatment with inhibitors for ERK1/2 and RSK-1. Conclusions: Data presented here demonstrate a direct stimulatory role for Galanin on cholangiocyte proliferation under physiological (sham) and pathological (BDL) conditions via a mechanism involving the activation of ERK1/2 and subsequent phosphorylation of RSK-1. Targeting Galanin or GalR1 may prove a useful strategy to regulate biliary mass during cholestatic liver injury.