The Expression And Function Of CD147 In Non-alcoholic Steatohepatitis

Non-alcoholic fatty liver disease(NAFLD)is a metabolic liver disease,which is characterized by the accumulation of fat in hepatocytes,resulting in non-alcoholic steatohepatitis(NASH),liver fibrosis,liver cirrhosis and eventually hepatocellular carcinoma(HCC).Hepatocyte death and inflammation is thought to be the main factor in the development of NASH and associated with increased severity of the disease and patients' outcomes.Additionally,fat metabolism,endoplasmic reticulum(ER)stress,mitochondria dysfunction and cytokine release may contribute to NASH.Hepatocyte is the largest population of liver,but it's vulnerable to injury by steatosis.Hepatocyte apoptosis has been shown to be positive correlation with the development of NASH.The molecules released by damaged hepatocytes trigger inflammation signals that accelerate NASH.CD147 is a member of immunoglobulin superfamily,also known as Basigin and EMMPRIN.CD147 is a transmembrane glycoprotein and expressed on cell membrane of tumor cells and inflammatory tissues.The previous studies showed that CD147 can induce MMPs expression and degrade extracellular matrix to facilitate the invasion and migration of cancer cells.CD147 also anticipates in the metabolism of cancer cells.Many researchers discovered that the interaction of CD147 and cyclophilins has an important role in regulating leukocyte recruitment and influencing immunologic disorders.The previous researches focus on liver fibrosis,cirrhosis and hepatocellular carcinoma caused by viral infection.They uncovered the mechanism of CD147 in the development of liver fibrosis and cancer.However the roles of CD147 in fatty liver disease are unclear,which is important for reverse and treatment of the disease.In order to provide theory basis for NASH therapies,this project investigated the expression of CD147 in NASH and the function of CD147 in hepatocytes,and uncovered the CD147-related signaling pathway.Part ?: The expression of CD147 in NASH mouse model.Firstly,we established the animal model with NASH characters by feeding methionine-choline-deficient(MCD)diet to mice and evaluated the degree of liver steatosis by H&E staining,the level of alanine aminotransferase(ALT)and aspartate aminotransferase(AST)in serum and the expression of related cytokines.The results showed that MCD diet induced fat accumulation,inflammatory cell infiltration,increased liver injury,as well as the overexpression of various cytokines.Secondly,western blot and real-time PCR analysis confirmed that CD147 expression was increased gradually.The results of IHC(Immunological histological chemistry)showed that CD147 was mainly expressed on hepatocytes of NASH tissues and there was no expression of normal liver tissues.Thirdly,we collected 5 donor liver samples and 21 fatty liver samples for detecting the expression of CD147 by IHC.The staining results demonstrated that CD147 was a positive expression in 18 liver samples.These results indicate high expression of CD147 may play an important role in the development of NASH.Part ?: Specific knockout CD147 of hepatocytes inhibited the development of NASH.The specific knockout CD147 mice were fed with MCD diet two weeks.The staining of H&E,oil red and level of ALT and AST showed that liver steatosis and injury in knockout mice were weaker than control group.AST level was significantly decreased(p < 0.01).In mouse liver,there was lower numbers of apoptosis cells in knockout mice compared to control mice by TUNEL staining.Increased Bcl-2 protein and decreased Bax protein in liver tissues of knockout mice indicated CD147 may contribute to hepatocyte apoptosis in the development of NASH.The real-time PCR results showed the ability of cytokines release was impaired in knockout mice,especially IL-1? and IL-18(p < 0.05 and p < 0.01,respectively).In conclusion,the CD147 deficiency in hepatocytes may inhibit NASH by reducing liver steatosis,liver cell death and inflammatory response.IL-1? and IL-18 are two members of IL-1 family and relate to the NLRP3 inflammasome signaling pathway.The expression of NLRP3 was increased in NASH mouse model gradually.But the level in liver of knockout mice was lower than control.In order to uncover the function of CD147 and NLRP3 in hepatocytes,we cultured primary hepatocytes with MCD medium to mimic liver steatosis of NASH in vitro.The expression of CD147 was increased after 24 h.The previous study showed CypA and CD147 collectively regulated inflammatory response.The ELISA result demonstrated an increased level of CypA in serum of NASH mice.In vitro,2.0 ?g/ml Cyp A stimulated the expression CD147 and NLRP3.These results suggest Cyp A and CD147 upregulate NLRP3 expression collectively.