| Background and AimsHepatitis is a serious public health problem in the world. Viral hepatitis is the main type of hepatitis, especially the hepatitis B caused by HBV infection in our country. The occurrence and development of these diseases are related to many factors, such as virus, host genetic susceptibility, impaired immunity and so on. These factors not only cause acute and chronic hepatitis, but also closely related with liver fibrosis, hepatic failure, hepatocellular carcinoma (HCC) and so on. The interaction between chemokines and cytokines is an important determinant that can contribute to the progress of the liver disease.Interferon γ (IFN-γ) plays a key role in defense against viral infections, which can mainly mediate Thl type inflammation. It can induce chemokine (C-X-C motif) ligands (CXCL9, CXCL10, CXCL11) and cytokines, such as interleukin (IL)-6,tumour necrosis factor(TNF)-α etc. The interactions between these inflammatory factors form a harmful inflammatory cycle, which is the primary mechanism lead to persistent hepatic infection. CXCL9, CXCL10 and CXCL11 are referred to as IFN-gamma inducible genes, which all belong to the chemokine (C-X-C motif) receptor 3 (CXCR3) ligand. CXCL10 have been most extensively investigated in the liver diseases. It is also known as IFN-gamma inducible protein 10 (IP-10).Many studies showed that IFN-inducible genes binding to their receptor CXCR3 can exert a variety of biological effects.It is not only conducive to viral clearance, but also secrete a variety of inflammatory mediators through recruiting inflammatory effector cells.These IFN- inducible genes are highly expressed in various viral hepatitis, further aggravate the tissue damage. They can play an important role in the occurrence, development, treatment and prognosis of chronic hepatitis. Inhibition of these inflammatory factors can improve the outcome of various liver diseases.The CXCR3 and its ligands may be new therapeutic targets for the treatment of hepatitis.Isoliquiritigenin(4,2’,4’-trihydroxychalcone, ISL)is a kind of isoflavone compounds. It is one of the active ingredient of anti-inflammatory activity of licorice. There is rarely content of ISL in glycyrrhiza but it has a wide range of pharmacological activity, such as antioxidant, anti-inflammatory, anti-platelet aggregation and anti-cancer. The anti-inflammatory effect of ISL has been widly studied in recent years. The present study aimed to explore the possibility function of ISL in the anti-hepatic inflammation and its potential anti-inflammatory mechanism in the liver cells.Methods1、The serum levels of CXCL10 were detected in the different severity of hepatitis B patients.The study population was divided into the following groups:hepatitis B virus carriers, mild chronic hepatitis B (CHB) patients, moderate CHB patients, severe CHB patients and healthy controls. Every group has 21 cases. The expression levels of serum CXCL10 was detected by ELISA.2、The cell model of IFN-y-induced inflammatory response in hepatocytes was constructed and the effect of ISL on inflammatory mediators was analyzed.HepG2 and L02 cells were exposed to different concentrations of IFN-γ and/or ISL for different times. The cytotoxicity of compounds to cells was evaluated by Cell Counting Kit 8(CCK8) assay; the mRNA or protein expression levels of CXCL9, CXCL10, CXCL11and IL-6 in intracellular and supernatant were measured by quantitative real time polymerase chain reaction(qRT-PCR) and ELISA, respectively.3、The molecular mechanisms about the influence of ISL on the expression of IFN-y-induced inflammatory mediators in hepatocytes was studied.HepG2 and L02 cells were exposed to IFN-y,different concentrations of ISL and IFN-γ combined with different concentrations of ISL.Western blot (WB) was used to examine the phosphorylated levels and (or) total protein levels of IFN-yinduced or ISL related signal pathways.These signal pathways were as follows:Janus kinase (JAK)/signal transduction and transcription 1 (STAT1),nuclear factor kappa B(NF-κB), interferon regulatory factor 3 (IRF3)/myeloid differentiation factor 88 (MyD88), mitogen activated protein kinase (MAPK),phosphatidylinositol 3-kinase (PI3K)/Protein Kinase B (Akt).Results1、The level of CXCL10 expression was correlated positively with the severity of hepatitis B patients.Compared with the healthy control group, the serum levels of CXCL10 in the hepatitis B patients were significantly increased.The difference was statistically significant (P< 0.05).The expression level of CXCL10 in severe CHB patients were the highest,suggesting that there is a correlation between CXCL10 and the severity of hepatitis B.2、After treatment with IFN-y in HepG2 and L02 cells, the expression levels of CXCL9, CXCL10, CXCL11 and IL-6 were high increased.These high expression levels can be significantly inhibited by ISL in a dose-dependently (IFN-γ+5μg/ml ISL group vs. IFN-y-induced group, P< 0.05). When the treatment dose of ISL was 5μg/ml, compared with the IFN-y-induced group, the inhibition of IL-6 was less than 50%,but the expression levels of the three chemokines were inhibited greater than 50%.These results indicated that the inhibitory effect of ISL on high expression of CXCL9-11 was more significantly better than on IL-6.3、The pretreatment of ISL could dose-dependently inhibit the activation of JAK1/STAT1, IRF3/MyD88, extracellular signal-regulated kinase(ERK)/MAPK, c-Jun N-terminal kinase (JNK)/MAPK and PI3K/Akt signaling pathways (IFN-γ+5μg/ml ISL group vs. IFN-y induced group, P< 0.05), but had no effect on the activation of JAK2/STAT1, NF-κB and p38/MAPK signaling pathways.ConclusionISL can inhibit the expression of IFN-y-induced inflammatory mediators in hepatocytes. Its molecular mechanism is through impacting the activation of JAK1/STAT1, IRF3/MyD88, ERK/MAPK, JNK/MAPK and PI3K/Akt signaling pathways. |
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