Antioxidant axis Nrf2-keap1-ARE in inhibition of alcoholic liver fibrosis by IL-22

Abstract

AIMTo explore the effect of interleukin (IL)-22 on in vitro model of alcoholic liver fibrosis hepatic stellate cells (HSCs), and whether this is related to regulation of Nrf2-keap1-ARE.METHODSHSC-T6 cells were incubated with 25, 50, 100, 200 and 400 μmol/L acetaldehyde. After 24 and 48 h, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to detect proliferation of HSCs to choose the best concentration and action time. We used the optimal concentration of acetaldehyde (200 μmol/L) to stimulate HSCs for 24 h, and treated the cells with a final concentration of 10, 20 or 50 ng/mL IL-22. The cell proliferation rate was detected by MTT assay. The cell cycle was analyzed by flow cytometry. The expression of nuclear factor-related factor (Nrf)2 and α-smooth muscle antigen was detected by western blotting and immunocytochemistry. The levels of malondialdehyde (MDA) and glutathione (GSH) were measured by spectrophotometry.RESULTSIn the MTT assay, when HSCs were incubated with acetaldehyde, activity and proliferation were higher than in the control group, and were most obvious after 48 h treatment with 200 μmol/L acetaldehyde. The number of cells in G0/G1 phases was decreased and the number in S phase was increased in comparison with the control group. When treated with different concentrations of IL-22, HSC-T6 cell activity and proliferation rate were markedly decreased in a dose-dependent manner, and cell cycle progression was arrested from G1 to S phase. Western blotting and immunocytochemistry demonstrated that expression of Nrf2 total protein was not significantly affected. Expression of Nrf2 nuclear protein was low in the control group, increased slightly in the model group (or acetaldehyde-stimulated group), and increased more obviously in the IL-22 intervention groups. The levels of MDA and GSH in the model group were significantly enhanced in comparison with those in the control group. In cells treated with IL-22, the MDA level was attenuated but the GSH level was further increased. These changes were dose-dependent.CONCLUSIONIL-22 inhibits acetaldehyde-induced HSC activation and proliferation, which may be related to nuclear translocation of Nrf2 and increased activity of the antioxidant axis Nrf2-keap1-ARE.

Matrine‐Type Alkaloids Inhibit Advanced Glycation End Products Induced Reactive Oxygen Species‐Mediated Apoptosis of Aortic Endothelial Cells In Vivo and In Vitro by Targeting MKK3 and p38MAPK Signaling

“…Enhancing the antioxidant system counterweights the cell injuries brought about by excessively produced ROS under certain pathological conditions. As a member of the “cap ‘n’ collar” family of basic leucine zipper transcription factors, Nrf2 induces the transcriptions of antioxidant enzymes by binding with ARE 35. Several genes of antioxidant enzymes were the downstream targets of Nrf2/ARE signaling.…”

“…As a member of the "cap 'n' collar" family of basic leucine zipper transcription factors, Nrf2 induces the transcriptions of antioxidant enzymes by binding with ARE. 35 Several genes of antioxidant enzymes were the downstream targets of Nrf2/ARE signaling. HO1, which has the ability of conversing heme into biliverdin, is one of the key phase II enzymes maintaining intracellular redox homeostasis by neutralizing oxidative stress.…”

Morin enhances hepatic Nrf2 expression in a liver fibrosis rat model

“…In the past decade, numerous studies proved that NF-E2-related factor 2 (Nrf2) plays a role as an important transcription factor in normal liver cells, and its activation could increase the expression of the downstream specific genes, such as the quinone oxidoreductase 1 (NQO1), heme oxygenase (HO-1), and glutathione, which play a role against oxidative stress[ 10 , 11 ]. Studies have shown that Nrf2 activation could resist oxidative stress caused by hepatic ischemia and injury, liver fibrosis, and drug-induced liver damage[ 12 - 15 ].…”

The role of IL‐22 in the resolution of sterile and nonsterile inflammation

“…2,8 Consistent with these findings, the total progenitor cell numbers in liver were positively correlated with increased levels of IL-22 expression in hepatocytes in patients with hepatitis B virus (HBV) or hepatitis C virus (HCV). 103 The role of IL-22 following sterile insults to liver 76,102 More recently, it has been demonstrated that IL-22 can promote nuclear translocation of nuclear factorrelated factor (Nrf2) in an in vitro model of alcoholic liver fibrosis (ALF) using hepatic stellate cells to show reduced fibrosis.…”

“…This effect is proposed to be regulated through induction of the antioxidant signalling cascades, resulting in elevated expression of its downstream target protein glutathione (GSH), and suppression of oxidative stress. 103 The role of IL-22 following sterile insults to liver…”