P2X7 receptor‐targeted regulation by tetrahydroxystilbene glucoside in alcoholic hepatosteatosis: A new strategy towards macrophage–hepatocyte crosstalk

Abstract

Background and Purpose:Regulating macrophage-hepatocyte crosstalk through P2X7 receptors has led to new pharmacological strategies to reverse alcoholic hepatosteatosis. We investigated how tetrahydroxystilbene glucoside (2354glu), isolated from Polygonum multiflorum, modulates macrophage-hepatocyte crosstalk during alcoholic hepatosteatosis.Experimental Approach: A model of alcoholic hepatosteatosis was established by giving ethanol intragastrically to C57BL/6 mice. HepG2 cells were incubated in conditioned medium from LPS+ATP-activated THP-1 human macrophages with silenced or overexpressed P2X7 receptors. THP-1 macrophages or mouse peritoneal macrophages were pretreated with 2354glu for 1 hr prior to LPS+ATP stimulation.Western blots, RT-PCR and immunohistochemical analysis were used, along with over-expression and silencing of P2X7 receptors.Key Results: Knockdown or overexpression of P2X7 receptors in THP-1 macrophages affected release of mature IL-1β and, subsequently, modulated lipid metabolism in HepG2 cells via the LKB-AMPK pathway. 2354glu ameliorated alcoholic hepatosteatosis in mice by regulating LKB1-AMPK-SREBP1 pathway and its target genes. Suppression of P2X7 receptor activation by 2354glu inhibited IL-1β release and reduced macrophage and neutrophil infiltration. In macrophages stimulated with LPS+ATP, expression of P2X7 receptors, caspase-1 and NF-κB, release of IL-1β, calcium influx and PI uptake were reduced by 2354glu. SIRT1-LKB1-AMPK-SREBP1 axis-mediated lipid accumulation in HepG2 cells was reduced when they were cultured with conditioned media from LPS+ATP-activated THP-1 macrophages pretreated with 2354glu.Abbreviations: 2345glu, tetrahydroxystilbene glucoside, 2,3,5,4 0 -tetrahydroxy-stilbene-2-O-β-D-glucoside; AMPK, AMP-activated protein kinase; LKB1, liver kinase B1; NLRP3, nucleotidebinding oligomerization domain-like receptor protein 3; SIRT1, sirtuin 1; SREBP1, sterol regulatory element-binding protein 1; TLRs, toll like receptors.

Role of ASM/Cer/TXNIP signaling module in the NLRP3 inflammasome activation

“…LPS is a crucial component of the extracellular membrane of gram-negative bacteria; it maintains the structural integrity of the cell and elicits pathogen-induced inflammation [ 21 ]. The LPS/ATP-stimulated J774A.1 cells and THP-1 macrophages represent a widely accepted in vitro model of inflammation used in the studies on the mechanism of NLRP3 inflammasome activation [ 22 , 23 ]. Hence, this model was employed in the current study.…”

Role of ASM/Cer/TXNIP signaling module in the NLRP3 inflammasome activation

“…LPS is a crucial component of the extracellular membrane of gram-negative bacteria; it maintains the structural integrity of the cell and elicits pathogen-induced in ammation [21]. The LPS/ATP-stimulated J774A.1 cells and THP-1 macrophages represent a widely accepted in vitro model of in ammation used in the studies on the mechanism of NLRP3 in ammasome activation [22,23]. Hence, this model was employed in the current study.…”

A Review of Pharmacology, Toxicity and Pharmacokinetics of 2,3,5,4′-Tetrahydroxystilbene-2-O-β-D-Glucoside

“…Its hepatoprotective effect was at least partly dependent on modulating the key regulators of lipid metabolism, inflammation, fibrosis and oxidative stress (Xu et al, 2019). In addition, Zhang et al (2020) found TSG had a good ameliorative effect on alcoholic hepatic steatosis by in vitro (THP-1 macrophages) and in vivo (C57BL/6 mice) experiments. Specifically, TSG inhibits P2X7R-NLRP3 signaling in macrophages, and is subsequently unperturbed by activated macrophages, thus inhibiting the lipid accumulation in hepatocytes to attenuate alcoholic hepatic steatosis (Zhang et al, 2020).…”