scholarly journals NLR Family Pyrin Domain‐Containing 3 Inflammasome Activation in Hepatic Stellate Cells Induces Liver Fibrosis in Mice

Hepatology ◽  
2019 ◽  
Vol 69 (2) ◽  
pp. 845-859 ◽  
Author(s):  
Maria Eugenia Inzaugarat ◽  
Casey D. Johnson ◽  
Theresa Maria Holtmann ◽  
Matthew D. McGeough ◽  
Christian Trautwein ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
Stellate Cells ◽  
Inflammasome Activation ◽  
Pyrin Domain

scholarly journals Inflammasome-mediated regulation of hepatic stellate cells

2009 ◽  
Vol 296 (6) ◽  
pp. G1248-G1257 ◽  
Author(s):  
Azuma Watanabe ◽  
Muhammad Adnan Sohail ◽  
Dawidson Assis Gomes ◽  
Ardeshir Hashmi ◽  
Jun Nagata ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Immune Cells ◽  
Hepatic Stellate Cells ◽  
Smooth Muscle Actin ◽  
Stellate Cells ◽  
Inflammasome Activation ◽  
Cellular Injury ◽  
Wild Type ◽  
Primary Mouse ◽  
Msu Crystals

The inflammasome is a cytoplasmic multiprotein complex that has recently been identified in immune cells as an important sensor of signals released by cellular injury and death. Analogous to immune cells, hepatic stellate cells (HSC) also respond to cellular injury and death. Our aim was to establish whether inflammasome components were present in HSC and could regulate HSC functionality. Monosodium urate (MSU) crystals (100 μg/ml) were used to experimentally induce inflammasome activation in LX-2 and primary mouse HSC. Twenty-four hours later primary mouse HSC were stained with α-smooth muscle actin and visualized by confocal microscopy, and TGF-β and collagen1 mRNA expression was quantified. LX-2 cells were further cultured with or without MSU crystals for 24 h in a transwell chemotaxis assay with PDGF as the chemoattractant. We also examined inhibition of calcium (Ca2+) signaling in LX-2 cells treated with or without MSU crystals using caged inositol 1,4,5-triphosphate (IP3). Finally, we confirmed an important role of the inflammasome in experimental liver fibrosis by the injection of carbon tetrachloride (CCl4) or thioacetamide (TAA) in wild-type mice and mice lacking components of the inflammasome. Components of the inflammasome are expressed in LX-2 cells and primary HSC. MSU crystals induced upregulation of TGF-β and collagen1 mRNA and actin reorganization in HSCs from wild-type mice but not mice lacking inflammasome components. MSU crystals inhibited the release of Ca2+ via IP3 in LX-2 cells and also inhibited PDGF-induced chemotaxis. Mice lacking the inflammasome-sensing and adaptor molecules, NLRP3 and apoptosis-associated speck-like protein containing CARD, had reduced CCl4 and TAA-induced liver fibrosis. We concluded that inflammasome components are present in HSC, can regulate a variety of HSC functions, and are required for the development of liver fibrosis.

scholarly journals Transcriptional repression of SIRT1 by protein inhibitor of activated STAT 4 (PIAS4) in hepatic stellate cells contributes to liver fibrosis

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Lina Sun ◽  
Zhiwen Fan ◽  
Junliang Chen ◽  
Wenfang Tian ◽  
Min Li ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Hepatic Stellate Cells ◽  
High Glucose ◽  
Interstitial Fibrosis ◽  
Stellate Cells ◽  
Quiescent State ◽  
Dependent Manner ◽  
Gene Promoters ◽  
Sirt1 Expression ◽  
Primary Mouse

Abstract Interstitial fibrosis represents a key pathological process in non-alcoholic steatohepatitis (NASH). In the liver, fibrogenesis is primarily mediated by activated hepatic stellate cells (HSCs) transitioning from a quiescent state in response to a host of stimuli. The molecular mechanism underlying HSC activation is not completely understood. Here we report that there was a simultaneous up-regulation of PIAS4 expression and down-regulation of SIRT1 expression accompanying increased hepatic fibrogenesis in an MCD-diet induced mouse model of NASH. In cultured primary mouse HSCs, stimulation with high glucose activated PIAS4 while at the same time repressed SIRT1. Over-expression of PIAS4 directly repressed SIRT1 promoter activity. In contrast, depletion of PIAS4 restored SIRT1 expression in HSCs treated with high glucose. Estrogen, a known NASH-protective hormone, antagonized HSC activation by targeting PIAS4. Lentivirus-mediated delivery of short hairpin RNA (shRNA) targeting PIAS4 in mice ameliorated MCD diet induced liver fibrosis by normalizing SIRT1 expression in vivo. PIAS4 promoted HSC activation in a SIRT1-dependent manner in vitro. Mechanistically, PIAS4 mediated SIRT1 repression led to SMAD3 hyperacetylation and enhanced SMAD3 binding to fibrogenic gene promoters. Taken together, our data suggest SIRT1 trans-repression by PIAS4 plays an important role in HSC activation and liver fibrosis.

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.

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