MAPK p38/Ulk1 pathway inhibits autophagy and induces IL-1β expression in hepatic stellate cells

Author(s):  
Li Jin ◽  
Juan Li ◽  
ShuJuan Yang ◽  
Rou Zhang ◽  
Chunhua Hu ◽  
...  

Background: In the past, hepatic stellate cells (HSCs) were considered to be noninflammatory cells and contribute to liver fibrosis by producing extracellular matrix. Recently, it was found that HSCs can also secrete cytokines and chemokines and therefore participate in hepatic inflammation. Autophagy participates in many immune response processes in immune cells. It is unclear whether autophagy is involved in inflammatory cytokine induction in HSCs. Methods: MAPK p38, Ulk1 phosphorylation and the Ulk1-Atg13 complex were analyzed in HSC-T6 cells after LPS treatment. The relationship between autophagy inhibition and inflammation was investigated in primary rat HSCs. Results: We discovered that LPS inhibited autophagy through MAPK p38. The activation of MAPK p38 induced Ulk1 phosphorylation, which disrupted the Ulk1-Atg13 complex and therefore inhibited autophagy. Furthermore, in primary rat HSCs, we demonstrated that autophagy inhibition regulated IL-1β induction, which depended on the MAPK p38/Ulk1 pathway. Conclusions: Our results reveal a continuous signaling pathway, MAPK p38-Ulk1 phosphorylation-Ulk1/Atg13 disruption, which inhibits autophagy and induces IL-1β expression in HSCs.

2009 ◽  
Vol 296 (6) ◽  
pp. G1248-G1257 ◽  
Author(s):  
Azuma Watanabe ◽  
Muhammad Adnan Sohail ◽  
Dawidson Assis Gomes ◽  
Ardeshir Hashmi ◽  
Jun Nagata ◽  
...  

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.


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Shai Z Fuchs ◽  
Bernardo Yusta ◽  
Laurie Baggio ◽  
Elodie Varin ◽  
Dianne Matthews ◽  
...  

Abstract A GLP-2 analogue is used in individuals with intestinal failure at risk for liver disease, yet the hepatic actions of GLP-2 are not understood. Treatment of high fat diet (HFD)-fed mice with GLP-2 did not modify the development of hepatosteatosis or hepatic inflammation. In contrast, Glp2r-/- mice exhibited increased hepatic lipid accumulation, deterioration in glucose tolerance, and upregulation of biomarkers of hepatic inflammation. Both mouse and human liver expressed the canonical GLP-2R, and hepatic Glp2r expression was upregulated in mice with hepatosteatosis. Cell fractionation localized the Glp2r to hepatic stellate cells (HSC), and markers of HSC activation and fibrosis were increased in livers from Glp2r-/- mice. Moreover, GLP-2 directly modulated gene expression in isolated HSCs ex vivo. Taken together, these findings define an essential role for the GLP-2R in hepatic adaptation to nutrient excess and unveil a gut hormone-HSC axis, linking GLP-2R signaling to control of hepatic stellate cell activation.


BMC Cancer ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Xia Liao ◽  
Yang Bu ◽  
Fan Chang ◽  
Fengan Jia ◽  
Ge Song ◽  
...  

Abstract Background Hepatic stellate cells (HSCs) have a key role in fibrogenesis and in the filtrates of the hepatocellular carcinoma (HCC) stroma, in which they are remodeled and play a critical role in HCC progression. However, the precise role of HSCs trending, infiltration and paracrine in orchestrating the stroma-derived oxaliplatin-resistance in HCC is still vague. Methods The chemo-resistant models were established to explore the correlation between HSC cells and the condition of chemoresistance. The HCC clinical samples were collected to confirm this phenomenon. Then, the relationship between secretory CCN3 from oxaliplatin-resistant HCC and the infiltration of HSCs in associated HCC microenvironment was evaluated. Finally, the role and mechanism of HSCs remodeling in the orchestration of oxaliplatin-resistant HCC were explored. Results The increased infiltration of HSCs and collagen accumulation were found in the microenvironment of oxaliplatin-resistant HCC. The cDNA profiles of the oxaliplatin-resistant HCC was reanalyzed, and CCN3 was one of the significantly increased genes. In HCC clinical samples, the levels of CCN3 and α-SMA are positively correlated, and high expression of CCN3 and α-SMA are positively associated with malignant phenotype and poor prognosis. Then the enhanced abilities of migration and proliferation of HSCs, and elevation of the cytokines paracrine from HSCs relating to HCC malignancy were proved in vitro and in vivo, and which were related to CCN3-ERK signaling pathway activation. Conclusions HSCs remodeling are positively related to CCN3 paracrine in hepatocellular carcinoma, which orchestrated the stroma-derived resistance to chemotherapy in HCC.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. SCI-36-SCI-36
Author(s):  
Christian Weber

Abstract Abstract SCI-36 During the past decade it has become increasingly clear that platelets exert important functions in the context of inflammation, beyond their role in hemostasis. Platelets may adhere to intact endothelial cells and promote local vascular inflammation by recruiting leukocytes via direct interactions or by secreting inflammatory mediators such as cytokines and chemokines. Accordingly, platelet-derived chemokines play a crucial role in directing leukocytes to sites of vascular injury or dysfunction, thereby contributing to neointimal hyperplasia or atherosclerosis. In addition, platelet-derived cytokines can shape the local inflammatory environment. In this overview, I will discuss the function of platelets as immune cells that potentiate vascular inflammation with a special focus on platelet-derived chemokines: their effects and interactions and their potential quality as targets for the treatment and/or prevention of cardiovascular disease. Disclosures: Weber: Carolus Therapeutics: Equity Ownership, Membership on an entity’s Board of Directors or advisory committees.


2004 ◽  
Vol 287 (1) ◽  
pp. G18-G26 ◽  
Author(s):  
Fabio Marra ◽  
Wanda Delogu ◽  
Ilaria Petrai ◽  
Sabrina Pastacaldi ◽  
Andrea Bonacchi ◽  
...  

Hepatic stellate cells (HSC) coordinate the liver wound-healing response through secretion of several cytokines and chemokines, including CCL2 (formerly known as monocyte chemoattractant protein-1). In this study, we evaluated the role of different proteins of the MAPK family (ERK, p38MAPK, and JNK) in the regulation of CCL2 expression by HSC, as an index of their proinflammatory activity. Several mediators activated all three MAPK, including TNF, IL-1, and PDGF. To assess the relative role of the different MAPKs, specific pharmacological inhibitors were used; namely, SB203580 (p38MAPK), SP600125 (JNK), and PD98059 (MEK/ERK). The efficacy and specificity of the different inhibitors in our cellular system were verified analyzing the enzymatic activity of the different MAPKs using in vitro kinase assays and/or testing the inhibition of phosphorylation of downstream substrates. SB203580 and SP600125 dose-dependently inhibited CCL2 secretion and gene expression induced by IL-1 or TNF. In contrast, inhibition of ERK did not affect the upregulation of CCL2 induced by the two cytokines. Finally, activin A was also found to stimulate CCL2 expression and to activate ERK, JNK, p38, and their downstream targets. Unlike in cells exposed to proinflammatory cytokines, all three MAPKs were required to induce CCL2 secretion in response to activin. We conclude that members of the MAPK family differentially regulate cytokine-induced chemokine expression in human HSC.


2020 ◽  
Vol 245 (2) ◽  
pp. 96-108 ◽  
Author(s):  
Debanjan Dhar ◽  
Jacopo Baglieri ◽  
Tatiana Kisseleva ◽  
David A Brenner

Hepatic fibrogenesis is a pathophysiological outcome of chronic liver injury hallmarked by excessive accumulation of extracellular matrix proteins. Fibrosis is a dynamic process that involves cross-talk between parenchymal cells (hepatocytes), hepatic stellate cells, sinusoidal endothelial cells and both resident and infiltrating immune cells. In this review, we focus on key cell-types that contribute to liver fibrosis, cytokines, and chemokines influencing this process and what it takes for fibrosis to regress. We discuss how mitochondria and metabolic changes in hepatic stellate cells modulate the fibrogenic process. We also briefly review how the presence of fibrosis affects development of hepatocellular carcinoma. Impact statement Advanced liver fibrosis results in cirrhosis, portal hypertension, and liver failure and often requires liver transplantation. Advanced liver fibrosis and cirrhosis are also major risk factors for hepatocellular carcinoma (HCC). Hepatic stellate cells (HSCs) play a pivotal role in the pathogenesis of liver fibrosis. In this review, we summarize the basic mechanisms that influence liver fibrosis development and how oxidative stress, mitochondrial dysfunction, and metabolic remodeling modulate HSC activation and indicate areas of potential therapeutic intervention.


1998 ◽  
Vol 275 (4) ◽  
pp. G847-G853 ◽  
Author(s):  
Jacquelyn J. Maher ◽  
John S. Lozier ◽  
Myron K. Scott

Hepatic stellate cells are widely recognized for their contribution to liver fibrosis. This study investigated whether these cells also promote hepatic inflammation by producing neutrophil chemoattractants. Specifically, stellate cells were examined as potential sources of cytokine-induced neutrophil chemoattractant (CINC), a rat chemokine resembling human interleukin-8. Stellate cells from normal rat liver expressed little or no CINC. In culture, CINC mRNA was induced rapidly, coinciding with the phenomenon of culture activation. CINC mRNA rose 4.6-fold within 3 days and was accompanied by secretion of immunoreactive and biologically active CINC protein (4.1 ng ⋅ μg DNA−1⋅ day−1). Studies in vivo demonstrated that CINC could be induced in stellate cells during liver injury. CINC mRNA rose significantly (4- to 6-fold) in two models of liver disease, both of which cause stellate cell activation. In summary, the data indicate that CINC is induced during stellate cell activation in culture and in vivo. They suggest that stellate cell-derived CINC can promote hepatic inflammation in vivo.


Sign in / Sign up

Export Citation Format

Share Document