Inhibitory effects of capsaicin on hepatic stellate cells and liver fibrosis

2014 ◽  
Vol 92 (5) ◽  
pp. 406-412 ◽  
Author(s):  
Fu-Xiang Yu ◽  
Yin-Yan Teng ◽  
Qian-Dong Zhu ◽  
Qi-Yu Zhang ◽  
Yin-He Tang
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Proliferation ◽  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Cell Apoptosis ◽  
Stellate Cells ◽  
Cell Counting ◽  
Mrna Levels ◽  
Inhibitory Effects ◽  
Production Of Hydrogen

Hepatic stellate cells (HSCs) play an important role in the process of liver fibrosis. In this study, we investigated the inhibitory effects of capsaicin on HSCs and liver fibrosis. Cultured HSCs were incubated with various concentrations of capsaicin. Cell proliferation was examined using a cell counting kit. Production of hydrogen peroxide was determined using a 2′,7′-dichlorofluorescin diacetate (DCFH-DA) assay. The mRNA and protein expression of target genes was analyzed by reverse transcription PCR and Western blot analysis, respectively. Cell apoptosis was evaluated by annexin V-FITC and propidium iodide (PI) costaining followed by flow cytometric analysis. A CCl4 rat liver fibrosis model was used to assess in vivo effects of capsaicin by histological examination and measurement of liver fibrosis markers, including hydroxyproline content, serum type III collagen, and hyaluronic acid (HA) levels. Our results show that capsaicin dose-dependently inhibited cell proliferation, suppressed cell activation, and decreased hydrogen peroxide production in cultured HSCs. Capsaicin reduced the mRNA levels of tissue inhibitors of metalloproteinase 1 (TIMP-1) and transforming growth factor-β1 (TGF-β1) in HSCs. Moreover, capsaicin-induced cell apoptosis was associated with increased expression of Bax, cytochrome c (cyt c), and caspase-3, but reduced levels of Bcl-2. The animal studies further revealed that capsaicin efficiently reduced the extent of liver fibrosis, inhibited HSC proliferation, and promoted cell apoptosis. Our findings suggest that capsaicin might inhibit fibrogenesis by inhibiting the activities of HSCs.

Norepinephrine induces calcium spikes and proinflammatory actions in human hepatic stellate cells

2006 ◽  
Vol 291 (5) ◽  
pp. G877-G884 ◽  
Author(s):  
Pau Sancho-Bru ◽  
Ramón Bataller ◽  
Jordi Colmenero ◽  
Xavier Gasull ◽  
Montserrat Moreno ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Portal Hypertension ◽  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Molecular Mechanisms ◽  
Nuclear Translocation ◽  
Stellate Cells ◽  
Luciferase Reporter ◽  
Dependent Manner ◽  
Cell Contraction

Catecholamines participate in the pathogenesis of portal hypertension and liver fibrosis through α1-adrenoceptors. However, the underlying cellular and molecular mechanisms are largely unknown. Here, we investigated the effects of norepinephrine (NE) on human hepatic stellate cells (HSC), which exert vasoactive, inflammatory, and fibrogenic actions in the injured liver. Adrenoceptor expression was assessed in human HSC by RT-PCR and immunocytochemistry. Intracellular Ca2+ concentration ([Ca2+]i) was studied in fura-2-loaded cells. Cell contraction was studied by assessing wrinkle formation and myosin light chain II (MLC II) phosphorylation. Cell proliferation and collagen-α1(I) expression were assessed by [3H]thymidine incorporation and quantitative PCR, respectively. NF-κB activation was assessed by luciferase reporter gene and p65 nuclear translocation. Chemokine secretion was assessed by ELISA. Normal human livers expressed α1A-adrenoceptors, which were markedly upregulated in livers with advanced fibrosis. Activated human HSC expressed α1A-adrenoceptors. NE induced multiple rapid [Ca2+]i oscillations (Ca2+ spikes). Prazosin (α1-blocker) completely prevented NE-induced Ca2+ spikes, whereas propranolol (nonspecific β-blocker) partially attenuated this effect. NE caused phosphorylation of MLC II and cell contraction. In contrast, NE did not affect cell proliferation or collagen-α1(I) expression. Importantly, NE stimulated the secretion of inflammatory chemokines (RANTES and interleukin-8) in a dose-dependent manner. Prazosin blocked NE-induced chemokine secretion. NE stimulated NF-κB activation. BAY 11-7082, a specific NF-κB inhibitor, blocked NE-induced chemokine secretion. We conclude that NE stimulates NF-κB and induces cell contraction and proinflammatory effects in human HSC. Catecholamines may participate in the pathogenesis of portal hypertension and liver fibrosis by targeting HSC.

scholarly journals Up-Regulated ATF4 Expression Increases Cell Sensitivity to Apoptosis in Response to Radiation

2017 ◽  
Vol 41 (2) ◽  
pp. 784-794 ◽  
Author(s):  
Ying Zong ◽  
Shijie Feng ◽  
Jinwei Cheng ◽  
Chenlin Yu ◽  
Guocai Lu
Keyword(s):  
Cell Proliferation ◽  
Transcription Factor ◽  
Cell Apoptosis ◽  
Hek293 Cells ◽  
Cell Counting ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Over Expression ◽  
Radiation Induced ◽  
Activating Transcription Factor

Background/Aims: Activating transcription factor 4 (ATF4) is a member of the activating transcription factor family which regulates the expression of genes involved in amino acid metabolism, redox homeostasis and ER stress responses. ATF4 is also over-expressed in human solid tumors, although its effect on responsiveness to radiation is largely unexplored. Methods: Real-time PCR was used to detect ATF4 mRNA levels in cells treated with different doses of 60Coγ radiation. Cell viability was assayed using a cell counting kit. The cell cycle was analyzed using flow cytometry, and cell apoptosis was assayed using Annexin V-PI double labeling. Small interfering RNA (siRNA) against ATF4 was transfected into ECV304 cells using Lipofectamine 2000. An ATF4 over-expression plasmid (p-ATF4-CGN) was transfected into HEK293 cells that endogenously expressed low levels of ATF4. The levels of intracellular reactive oxygen species (ROS) were measured using CM-H2DCFDA as a probe. Results: ATF4 mRNA and protein expression levels were higher after radiation and increased in a dose- and time-dependent manner in AHH1 lymphoblast cells (P < 0.05). An increase in ATF4 levels was also observed after radiation in primary murine spleen cells, human endothelial ECV304 cells, human liver LO2 cells, breast cancer MCF7 cells, and human hepatocellular carcinoma HEPG2 cells. No change was observed in human embryonic kidney 293 (HEK293) cells. Over-expressing ATF4 in HEK293 cells inhibited cell proliferation, increased cell apoptosis and significantly increased the proportion of cells in G1 phase. Conversely, when ATF4 expression was knocked down using siRNA in ECV304 cells, it protected the cells from radiation-induced apoptosis. These findings suggest that ATF4 may play a role in radiation-induced cell killing by inhibiting cell proliferation and promoting cell apoptosis. Conclusions: In this study, we found that radiation up-regulated the expression of ATF4. We used ATF4 knockdown and over-expression systems to show that ATF4 may play a role in radiation-induced cellular apoptosis.

Diminished retinoic acid signaling in hepatic stellate cells in cholestatic liver fibrosis

1997 ◽  
Vol 272 (3) ◽  
pp. G589-G596 ◽  
Author(s):  
M. Ohata ◽  
M. Lin ◽  
M. Satre ◽  
H. Tsukamoto
Keyword(s):  
Retinoic Acid ◽  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Transforming Growth Factor ◽  
Mrna Level ◽  
Stellate Cells ◽  
Polymerase Chain Reaction Analysis ◽  
Retinol Binding Protein ◽  
Mrna Levels ◽  
Duct Ligation

Hepatic stellate cells (HSC) participate in liver fibrogenesis via myofibroblastic activation, the extent of which appears to correlate with the loss of cellular vitamin A. The present study has tested a hypothesis that HSC activation is associated with diminished retinoic acid (RA) signaling. Pure HSC were isolated from rats with cholestatic liver fibrosis induced by bile duct ligation (BDL) and sham-operated animals (Sham). Northern blot analysis of HSC RNA from BDL confirmed fibrogenic activation of the cells with enhanced mRNA levels for procollagen-alpha1(I) and transforming growth factor-beta1 (TGF-beta1). Competitive polymerase chain reaction analysis showed selective reductions in the mRNA levels of RA receptor (RAR)-beta and retinoid X receptor (RXR)-alpha to 20 and 17% of the Sham HSC. The mRNA level for cellular retinol binding protein I, a gene with RA responsive element (RARE), was also suppressed by 78% in BDL. The concentrations of all-trans-RA and 9-cis-RA were decreased in HSC from BDL. Nuclear extracts of these cells showed diminished binding activity to the RARE, whereas activity of AP-1, a transcription factor known to be antagonized by RAR and RXR, was enhanced. These results demonstrate diminished RA signaling in HSC from cholestatic liver fibrosis, which appeared to have resulted from RA deficiency and suppressed expression of RAR-beta and RXR-alpha. Furthermore, the reciprocal enhancement of AP-1 activity and coordinately increased expression of an AP-1 responsive gene, TGF-beta1, suggest a permissive role of the diminished RA signaling in promoting AP-1 activity and TGF-beta1 expression.

scholarly journals Activation of Hepatic Stellate Cells is Inhibited by microRNA-378a-3p via Wnt10a

2016 ◽  
Vol 39 (6) ◽  
pp. 2409-2420 ◽  
Author(s):  
Fujun Yu ◽  
XuFei Fan ◽  
Bicheng Chen ◽  
Peihong Dong ◽  
Jianjian Zheng
Keyword(s):  
Cell Proliferation ◽  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Cardiac Fibrosis ◽  
Smooth Muscle Actin ◽  
Stellate Cells ◽  
Luciferase Reporter ◽  
Healthy Controls ◽  
Fibrotic Liver ◽  
Collagen Expression

Background/Aims: Wnt/β-catenin pathway is involved in liver fibrosis and microRNAs (miRNAs) are considered as key regulators of the activation of hepatic stellate cells (HSCs). A recent study showed the protective role of miR-378a-3p against cardiac fibrosis. However, whether miR-378a-3p suppresses Wnt/β-catenin pathway in liver fibrosis is largely unknown. Methods: miR-378a-3p expression was detected in carbon tetrachloride-induced liver fibrosis and activated HSCs. Effects of miR-378a-3p overexpression on HSC activation and Wnt/β-catenin pathway were analyzed. Bioinformatic analysis was employed to identify the potential targets of miR-378a-3p. Serum miR-378a-3p expression was analyzed in patients with cirrhosis. Results: Reduced miR-378a-3p expression was observed in the fibrotic liver tissues and activated HSCs. Up-regulation of miR-378a-3p inhibited HSC activation including cell proliferation, α-smooth muscle actin (α-SMA) and collagen expression. Moreover, miR-378a-3p overexpression resulted in Wnt/β-catenin pathway inactivation. Luciferase reporter assays demonstrated that Wnt10a, a member of Wnt/β-catenin pathway, was confirmed to be a target of miR-378a-3p. By contrast, miR-378a-3p inhibitor contributed to HSC activation, with an increase in cell proliferation, α-SMA and collagen expression. But all these effects were blocked down by silencing of Wnt10a. Notably, sera from patients with cirrhosis contained lower levels of miR-378a-3p than sera from healthy controls. Receiver operating characteristic curve analysis suggested that serum miR-378a-3p differentiated liver cirrhosis patients from healthy controls, with an area under the curve of ROC curve of 0.916. Conclusion: miR-378a-3p suppresses HSC activation, at least in part, via targeting of Wnt10a, supporting its potential utility as a novel therapeutic target for liver fibrosis.

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