ASK1 Enhances Angiotensin II-Induced Liver Fibrosis

Autor: Pei-Pei, Fang, Chen-Wei, Pan, Wei, Lin, Jie, Li, Shan-Shan, Huang, Guang-Yao, Zhou, Wen-Jun, Du, Qiang, Li
Rok vydání: 2019
Předmět:
Zdroj: Mediators of Inflammation
ISSN: 1466-1861
Popis: Background Apoptosis signal-regulating kinase 1 (ASK1) has been reported to induce fibrotic signaling in the setting of oxidative stress. However, the role of ASK1 and its mechanism of action in angiotensin II- (Ang II-) induced liver fibrosis remain largely unknown. Methods Human hepatic LX-2 stellate cells were treated with Ang II alone or cotreated with Ang II plus an ASK1 inhibitor (GS-4997) or siRNA-targeting ASK1. Immunofluorescent staining, real-time PCR, and western blotting were used to determine the expressionof α-SMA, Col I, and Col III expression. Cell viability was assessed by the CCK-8 assay. The concentrations of IL-1β, IL-18, and TNF-α in conditioned medium were determined by ELISA. The levels of intracellular ROS in LX-2 cells were analyzed using a ROS assay kit. Exosome size was determined by electron microscopy. Results Ang II markedly increased the expression of extracellular matrix (ECM) proteins (α-SMA, Col I, and Col III) and proinflammatory cytokines (IL-1β, IL-18, and TNF-α). Ang II also increased the expression of endoplasmic reticulum stress (ERS) markers (GRP78, p-PERK, and CHOP) and p-ASK1. Results also showed that pretreatment with GS-4997 or siRNA could abolish all the abovementioned effects on LX-2 cells. Furthermore, we found that exosome release caused by ASK1-mediated ERS was involved in the activation of LX-2 cells by Ang II. The activation of LX-2 cells could be blocked by treating the exosomes with annexin. Conclusions In summary, we found that ASK1 mediates Ang II-activated ERS in HSCs and the subsequent activation of HSCs, suggesting a promising strategy for treating liver fibrosis.
Databáze: OpenAIRE
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