Gene/Protein Disease Symptom Drug Enzyme Compound
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The hepatic wound-healing response is a complex process involving many different cell types and factors. It leads to the formation of excessive matrix and a fibrotic scar, which ultimately disrupts proper functioning of the liver and establishes cirrhosis. Activated hepatic myofibroblasts, which are derived from cells such as hepatic stellate cells (HSCs), play a key role in this process. Upon chronic liver injury, there is an upregulation in the local neuroendocrine system and it has recently been demonstrated that activated HSCs express specific receptors and respond to different components of this system. Neuroendocrine factors and their receptors participate in a complex network that modulates liver inflammation and wound healing, and controls the development and progression of liver fibrosis. The first part of this review provides an overview of the molecular mechanisms governing hepatic wound healing. In the second section, we explore important components of the hepatic neuroendocrine system and their recently highlighted roles in HSC biology and hepatic fibrogenesis. We discuss the therapeutic interventions that are being developed for use in antifibrotic therapy.
Expert Rev Mol Med 2008 Apr 29
PMID:Wound healing and local neuroendocrine regulation in the injured liver. 1844 46

Infection with hepatitis C virus (HCV) is a major cause of chronic liver disease. Hepatic fibrosis may develop in subjects with chronic HCV infection, culminating in cirrhosis and an increased risk of hepatocellular carcinoma. The rate of development of fibrosis varies substantially between individuals; while it is influenced by a number of demographic and environmental factors, these account for only a small proportion of the variability. There are no clinical markers or tests that predict the rate of fibrosis progression in an individual subject. Thus, there has been increasing interest in the influence of host genetic factors on the rate of disease progression, and whether a genetic signature can be developed to reliably identify individuals at risk of severe disease. Numerous case-control, candidate gene, allele-association studies have examined the relationship between host single nucleotide polymorphisms or other genetic mutations and fibrosis in patients with chronic HCV infection. However, these studies have generally been irreproducible and disappointing. As seen with genetic studies for other diseases, small study cohorts and poor study design have contributed to limited meaningful findings. The successful determination of genetic signatures for fibrosis progression in chronic HCV will require multicenter collaborations using genome-wide association studies, with large, phenotypically well-defined sample sets. While these studies will require a significant financial commitment, a successful outcome offers the potential for personalized therapy and better patient management.
Mol Diagn Ther 2008
PMID:Recognition of genetic factors influencing the progression of hepatitis C : potential for personalized therapy. 1865 17

Activation of hepatic stellate cells during liver fibrosis is a major event facilitating an increase in extracellular matrix deposition. The up-regulation of smooth muscle alpha-actin and collagen type I is indicative of the activation process. The involvement of cysteine cathepsins, a class of lysosomal cysteine proteases, has not been studied in conjunction with the activation process of hepatic stellate cells. Here we report a nuclear cysteine protease activity partially attributed to cathepsin F, which co-localizes with nuclear speckles. This activity can be regulated by treatment with retinol/palmitic acid, known to reduce the hepatic stellate cell activation. The treatment for 48 h leads to a decrease in activity, which is coupled to an increase in cystatin B and C transcripts. Cystatin B knockdown experiments during the same treatment confirm the regulation of the nuclear activity by cystatin B. We demonstrate further that the inhibition of the nuclear activity by E-64d, a cysteine protease inhibitor, results in a differential regulation of smooth muscle alpha-actin and collagen type I transcripts. On the other hand, cathepsin F small interfering RNA transfection leads to a decrease in nuclear activity and a transcriptional down-regulation of both activation markers. These findings indicate a possible link between nuclear cathepsin F activity and the transcriptional regulation of hepatic stellate cell activation markers.
Mol Biol Cell 2008 Oct
PMID:Nuclear cathepsin F regulates activation markers in rat hepatic stellate cells. 1866 30

Recent studies have revealed a close relationship between insulin resistance (IR) and the progression of chronic liver diseases, although relatively little is known regarding the possible mechanisms involved. The aim of this study was to elucidate the impact of IR on the development of liver fibrosis and hepatocarcinogenesis using obese diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Liver fibrosis development and glutathione-S-transferase placental form (GST-P)-positive pre-neoplastic lesions were both markedly accelerated in OLETF rats, being induced by pig serum and diethylnitrosamine (DEN), respectively. In the fibrosis experiment, alpha-smooth muscle actin-positive activated hepatic stellate cells (HSCs) also significantly increased in OLETF rats along with augmentation of the hepatic collagen content and transforming growth factor-beta1. Our in vitro study showed that both glucose and insulin stimulated the proliferation of activated HSCs, and the combination treatment exerted an additive effect. In the DEN model, neovascularization, which plays a pivotal role in hepatocarcinogenesis, was up-regulated in OLETF rats almost in parallel with pre-neoplastic lesion development and a potent angiogenic factor, vascular endothelial growth factor. High glucose and insulin also significantly augmented the in vitro neovascularization via extracellular signal-regulated kinase 1/2 phosphorylation. Similar to the effect on the activated HSCs, co-existence of both factors exerted a more potent effect than either single factor. In conclusion, these results indicated that the IR status directly accelerated liver fibrosis development and hepatocarcinogenesis at least partly through the stimulation of activated HSC proliferation and hepatic neovascularization, respectively, in the rat.
Int J Mol Med 2008 Dec
PMID:Impact of insulin resistance on the progression of chronic liver diseases. 1902 Jul 79

Liver fibrosis is currently assessed by liver biopsy, a costly and rather cumbersome procedure that is unsuitable for frequent patient monitoring, which drives research into biomarkers for this purpose. To investigate whether the serum N-glycome contains information suitable for this goal, we developed a 96-well plate-based serum N-glycomics sample preparation protocol that only involves fluid transfer steps and incubations in a PCR thermocycler yielding 8-aminopyrene-1,3,6-trisulfonic acid-labeled N-glycans. These N-glycans are then ready for analysis on the capillary electrophoresis-based DNA sequencers that are the current standard in clinical genetics laboratories worldwide. Subsequently we performed a multicenter, blinded study of 376 consecutive chronic hepatitis C virus patients for which liver biopsies and extensive serum biochemistry data were available. Among patients, the METAVIR fibrosis stage distribution was as follows: 10.6% F0, 44.4% F1, 20.5% F2, 18.4% F3, and 6.1% F4. We found that the ratio of two N-glycans, here called GlycoFibroTest, correlates with the histological fibrosis stage equally well as FibroTest (rho = 0.4-0.5 in F1-F4), which is used in the clinic today. Finally using affinity chromatography we depleted sera of immunoglobulin G, and this resulted in a complete removal of the undergalactosylated biantennary glycans from the N-glycome, which are partially determining GlycoFibroTest.
Mol Cell Proteomics 2009 May
PMID:GlycoFibroTest is a highly performant liver fibrosis biomarker derived from DNA sequencer-based serum protein glycomics. 1918 23

Compelling evidence indicates the pro-fibrogenic action of leptin in liver. Peroxisome proliferator-activated receptor-gamma (PPARgamma) can reverse hepatic stellate cell (HSC) activation and maintain HSC quiescence. HSC activation, a key step in the development of liver fibrosis, is coupled with the up-expression of leptin and the dramatic down-expression of PPARgamma. The present study is aimed to assess the effect of leptin on PPARgamma gene expression in primary cultured rat HSCs and investigate the related mechanisms by using Western blotting analysis, real-time PCR, transient transfection approach, and cell growth analysis. The results suggest that leptin negatively regulates PPARgamma gene expression at mRNA level, protein level and PPARgamma gene promoter activity level in HSCs. The inhibitory effect of leptin on PPARgamma gene expression contributes to cell growth of activated HSCs in vitro. Phosphatidylinositol 3-kinase/AKT (PI-3 K/AKT) and extracellular signal-regulated kinase (ERK) signaling pathways mediate the leptin-induced inhibition of PPARgamma gene expression. In summary, these findings suggest that leptin down-regulates PPARgamma gene expression through activation of PI-3 K/AKT or ERK signaling pathway in primary cultured rat HSCs. Our results might provide novel insights into the mechanisms for the pro-fibrogenic action of leptin in liver.
Mol Cell Biochem 2009 May
PMID:PI-3 K/AKT and ERK signaling pathways mediate leptin-induced inhibition of PPARgamma gene expression in primary rat hepatic stellate cells. 1919 Oct 8

Plant flavonoids are emerging as potent therapeutic drugs effective against a wide range of free radical-mediated diseases. Morin (3,5,7,2',4'-pentahydroxyflavone), a member of flavonols, is an important bioactive compound by interacting with nucleic acids, enzymes and protein. In this study, we found that morin (30 mg/kg body weight) by oral administration offers protection against hyperammonemia by means of reducing blood ammonia, oxidative stress and enhancing antioxidant status in ammonium chloride-induced (100 mg/kg body weight; i.p) hyperammonemic rats. Enhanced blood ammonia, plasma urea, lipid peroxidation in circulation and tissues (liver and brain) of ammonium chloride-treated rats was accompanied by a significant decrease in the tissues levels of superoxide dismutase (SOD), catalase, reduced glutathione (GSH) and glutathione peroxidase (GPx). Morin administered rats showed a significant reduction in ammonia, urea, lipid peroxidation with a simultaneous elevation in antioxidant levels. Cotreatment with morin prevented the elevation of liver marker enzymes induced by ammonium chloride. The body weight of the animals decreased significantly on ammonium chloride administration when compared with control group. However, cotreatment with morin significantly prevented the decrease of the body weight caused by ammonium chloride. Hyperammonemic rats show liver fibrosis, steatosis, sinusoidal dilatation, etc., along with necrosis, microcystic degeneration in brain. All these changes were reduced in hyperammonemic rats treated with Morin, which too correlated with the biochemical observations. In conclusion, these findings indicate that morin exert antioxidant potential and offer protection against ammonium chloride-induced hyperammonemia. But the exact underlying mechanism needs to be elucidated.
Mol Cell Biochem 2009 Jul
PMID:Morin a flavonoid exerts antioxidant potential in chronic hyperammonemic rats: a biochemical and histopathological study. 1923 24

Cholangiocyte proliferation is triggered during extrahepatic bile duct obstruction induced by bile duct ligation, which is a common in vivo model used for the study of cholangiocyte proliferation and liver fibrosis. The proliferative response of cholangiocytes during cholestasis is regulated by the complex interaction of several factors, including gastrointestinal hormones, neuroendocrine hormones and autocrine or paracrine signalling mechanisms. Activation of biliary proliferation (ductular reaction) is thought to have a key role in the initiation and progression of liver fibrosis. The first part of this review provides an overview of the primary functions of cholangiocytes in terms of secretin-stimulated bicarbonate secretion--a functional index of cholangiocyte growth. In the second section, we explore the important regulators, both inhibitory and stimulatory, that regulate the cholangiocyte proliferative response during cholestasis. We discuss the role of proliferating cholangiocytes in the induction of fibrosis either directly via epithelial mesenchymal transition or indirectly via the activation of other liver cell types. The possibility of targeting cholangiocyte proliferation as potential therapy for reducing and/or preventing liver fibrosis, and future avenues for research into how cholangiocytes participate in the process of liver fibrogenesis are described.
Expert Rev Mol Med 2009 Feb 25
PMID:Cholangiocyte proliferation and liver fibrosis. 1923 26

Yin-Chen-Hao-Tang (YCHT) is recognized as a hepatoprotective agent for various types of liver diseases. Proteomics approaches were used to study hepatic and serum protein expression changes in bile duct ligated (BDL) rats following YCHT treatment for 27 days. Two-dimensional gel electrophoresis was used to analyze proteome changes. Of the proteins that exhibited changes, 17 were identified by means of matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry. The major effect of YCHT was evident in cytoskeleton related protein, plectin-1. In addition, proteins involved in metabolism of lipids were also shown to be affected, including low-density lipoprotein receptor-related protein 2 precursor (glycoprotein 330) and apolipoprotein A-I precursor (ApoA-I). Significant up-regulation of keratin 8 and 19 was found in liver tissue of BDL rats. Supplementation with YCHT also triggered alterations in the above proteins. Interestingly, YCHT treatment caused a statistically significant down-regulation in the secretion of monocyte chemoattractant protein-1 (MCP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in BDL rats with fibrosis. Our results suggested that YCHT may be useful for treatment of liver fibrosis because of its possible antiapoptotic properties, and the therapeutic effects of YCHT on liver diseases might be associated with its lipid biosynthesis regulation.
Int J Mol Med 2009 Apr
PMID:Changes of hepatic proteome in bile duct ligated rats with hepatic fibrosis following treatment with Yin-Chen-Hao-Tang. 1928 23

Small interfering RNA (siRNA) and short hairpin RNA (shRNA) targeting different regions of transforming growth factor beta1 (TGF-beta1) mRNA were designed and the silencing effect was determined after transfection into immortalized rat liver stellate cells (HSC-T6). There was not only significant decrease in TGF-beta1, tissue inhibitor of metalloproteinase 1 (TIMP-1), alpha-smooth muscle actin (alpha-SMA) and type I collagen after transfection with TGF-beta1 siRNAs, but also synergism in gene silencing when siRNAs targeting two different start sites were used as a pool for transfection. The two siRNA sequences which efficiently inhibited TGF-beta1 gene expression were converted to shRNAs via cloning into the pSilencer1.0. There was significant decrease in TGF-beta1 and TIMP-1 when HSC-T6 cells were transfected with pshRNA targeting the same regions of TGF-beta1 mRNA as siRNAs. Furthermore, TGF-beta1 gene silencing in HSC-T6 cells significantly decreased the levels of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1beta). In conclusion, both siRNA and shRNA showed sequence-specific and dose dependent TGF-beta1 gene silencing and have the potential to treat liver fibrosis.
Mol Pharm
PMID:TGF-beta1 gene silencing for treating liver fibrosis. 1938 65


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