Faculty Opinions recommendation of Reduction of advanced liver fibrosis by short-term targeted delivery of an angiotensin receptor blocker to hepatic stellate cells in rats.

Author(s):  
Stephen Stewart ◽  
Ahmad Al Rifai
2021 ◽  
Vol 12 ◽  
Author(s):  
Shiyun Pu ◽  
Yanping Li ◽  
Qinhui Liu ◽  
Xu Zhang ◽  
Lei Chen ◽  
...  

Background and Purpose: Activation of hepatic stellate cells (HSC) is a central driver of liver fibrosis. 5-lipoxygenase (5-LO) is the key enzyme that catalyzes arachidonic acid into leukotrienes. In this study, we examined the role of 5-LO in HSC activation and liver fibrosis.Main Methods: Culture medium was collected from quiescent and activated HSC for target metabolomics analysis. Exogenous leukotrienes were added to culture medium to explore their effect in activating HSC. Genetic ablation of 5-LO in mice was used to study its role in liver fibrosis induced by CCl4 and a methionine-choline-deficient (MCD) diet. Pharmacological inhibition of 5-LO in HSC was used to explore the effect of this enzyme in HSC activation and liver fibrosis.Key Results: The secretion of LTB4 and LTC4 was increased in activated vs. quiescent HSC. LTB4 and LTC4 contributed to HSC activation by activating the extracellular signal-regulated protein kinase pathway. The expression of 5-LO was increased in activated HSC and fibrotic livers of mice. Ablation of 5-LO in primary HSC inhibited both mRNA and protein expression of fibrotic genes. In vivo, ablation of 5-LO markedly ameliorated the CCl4- and MCD diet-induced liver fibrosis and liver injury. Pharmacological inhibition of 5-LO in HSC by targeted delivery of the 5-LO inhibitor zileuton suppressed HSC activation and improved CCl4- and MCD diet-induced hepatic fibrosis and liver injury. Finally, we found increased 5-LO expression in patients with non-alcoholic steatohepatitis and liver fibrosis.Conclusion: 5-LO may play a critical role in activating HSC; genetic ablation or pharmacological inhibition of 5-LO improved CCl4-and MCD diet-induced liver fibrosis.


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.


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