Potentiation of hepatic stellate cell activation by extracellular ATP is dependent on P2X7R-mediated NLRP3 inflammasome activation. (March 2017)

• Record Type: Journal Article
• Authors: Jiang, Shuang; Zhang, Yu; Zheng, Jin-Hua; Li, Xia; Yao, You-Li; Wu, Yan-Ling; Song, Shun-Zong; Sun, Peng; Nan, Ji-Xing; Lian, Li-Hua
• Is Part Of: Pharmacological research. Volume 117(2017:Mar.)
• Page Start: 82
• Page End: 93
• Publication Date: 2017-03
• Subjects: ASC apoptosis-associated speck-like protein containing CARD -- ATP adenosine 5′-triphosphate -- DAMP danger-associated molecular patterns -- ECM excessive extracellular matrix -- HSC hepatic stellate cells -- NLRP3 NOD-like receptor family pyrin domain containing 3 -- PAMP pathogen-associated molecular patterns -- P2x7R purinergic receptor P2x7 -- TNF-α tumor necrosis factor (TNF)-α; A438079 (PubChem CID: 11673921); Liver fibrosis -- Hepatic stellate cells -- P2X7 receptor -- Inflammasome -- NLRP3; Pharmacology -- Periodicals; Pharmacology -- Periodicals; Research -- Periodicals; Médicaments -- Recherche -- Périodiques; Pharmacologie -- Périodiques; 615.105
• DOI: 10.1016/j.phrs.2016.11.040
• Languages: English
• ISSNs: 1043-6618

Abstract

Graphical abstract: Abstract: Purinergic receptor P2x7 (P2x7R) is a key modulator of liver inflammation and fibrosis. The present study aimed to investigate the role of P2x7R in hepatic stellate cells activation. Lipopolysaccharide (LPS) or the conditioned medium (CM) from LPS-stimulated RAW 264.7 mouse macrophages was supplemented to human hepatic stellate cells, LX-2 for 24 h and P2x7R selective antagonist A438079 (10 μM) was supplemented to LX-2 cells 1 h before LPS or CM stimulation. In addition LX-2 cells were primed with LPS for 4 h and subsequently stimulated for 30 min with 3 mM of adenosine 5′-triphosphate (ATP). A438079 was supplemented to LX-2 cells 10 min prior to ATP. Directly treated with LPS on LX-2 cells, mRNA expressions of interleukin (IL)-1β, IL-18 and IL-6 were increased, as well as mRNA expressions of P2x7R, caspase-1, apoptosis-associated speck-like protein containing CARD (ASC) and NOD-like receptor family, pyrin domain containing 3 (NLRP3) mRNA. LPS also increased α-smooth muscle actin (α-SMA) and type I collagen mRNA expressions, as well as collagen deposition. Interestingly treatment of LX-2 cells with LPS-activated CM exhibited the greater increase of above factors than those in LX-2 cells directly treated with LPS. Pretreatment of A438079 on LX-2 cells stimulated by LPS or LPS-activated CM both suppressed IL-1β mRNA expression. LPS combined with ATP dramatically increased protein synthesis and cleavage of IL-1β and its mRNA level than those in HSC treated with LPS or ATP alone. Additionally LX-2 cells primed with LPS and subsequently stimulated for 30 min with ATP greatly increased mRNA and protein expression of caspase-1, NLRP3 and P2x7R, as well as liver fibrosis markers, α-SMA and type I collagen. These events were remarkably suppressed by A438079 pretreatment. siRNA against P2x7R reduced protein expression of NLRP3 and α-SMA, and suppressed deposition and secretion of type I collagen. The involvement of P2X7R-mediated NLRP3 inflammasome activation in IL-1β production of HSC might contribute to ECM deposition and suggests that blockade of the P2x7R-NLRP3 inflammasome axis represents a potential therapeutic target to liver fibrosis.