The Role And Mechanism Of MSP-RON Signal Axis In Regulating The Pathological Progression Of Liver Fibrosis

Background Liver cirrhosis is a progressive and diffuse fibrous change in liver tissue caused by one or more causes,and it is the terminal stage of many chronic liver diseases.Liver fibrosis is a pathological change in the process of liver tissue self-repair after chronic injury,and it is the pivotal link in the progression of chronic hepatitis to cirrhosis.At present,there is still a lack of effective drug treatments for liver fibrosis in clinical practice.Fibroblasts play an important role in the formation of liver fibrosis,and epithelial-mesenchymal transition is considered to be one of the important sources of fibroblasts.Through epithelial-mesenchymal transition,quiescent hepatic stellate cells,hepatocytes and bile duct cells with epithelial phenotype can become fibroblasts with mesenchymal phenotype and participate in the occurrence and development of liver fibrosis.Macrophage stimulating protein(MSP)is mainly secreted into the blood by hepatocytes.Receptor tyrosine protein kinase RON(Recepteur d’origine nantais)is a specific cell membrane receptor for MSP.The MSP-RON signal pathway plays an extremely important role in the epithelial-mesenchymal transition of mammalian cells.In the liver,RON is mainly expressed in macrophages and hepatocytes.Mature MSP binds to the hepatocyte surface receptor RON through the autocrine pathway and the paracrine pathway binds to the Kupffer cell surface receptor RON to maintain liver homeostasis and regulate the synthesis of inflammatory mediators,affecting the liver’s inflammatory response.This study aims to clarify the expression characteristics of the MSP-RON pathway in liver fibrosis/cirrhosis,and to evaluate its potential as a prognostic biomarker of liver cirrhosis.This research will start with a mouse model of liver fibrosis and combine in vitro cell experiments to study the feasibility and effectiveness of targeting the MSP-RON pathway in the treatment of liver fibrosis,and conduct an in-depth study of its mechanism.Method Part Ⅰ:This research used ELISA to detect the expression level of MSP in the serum of patients with liver cirrhosis and healthy controls and collects clinical data to analyze the expression characteristics of MSP in patients with liver cirrhosis,and evaluated the effect of MSP on patients with liver cirrhosis in combination with MELD score and Child-Pugh classification of prognostic assessment.Finally,the liquid-phase chip was used to detect the expression levels of various cytokines in the serum of patients with liver cirrhosis to explore the potential mechanism of MSP involved in regulating liver fibrosis and the pathological progress of liver cirrhosis.Part Ⅱ:Our research constructed a CCl4-induced mouse liver fibrosis model and pathological staining,liver function testing,Western Blot and ELISA were used to evaluate the expression characteristics of the MSP-RON signaling pathway in liver fibrosis.Target MSP blockade Antibodies and small molecule inhibitors targeting RON were used to treat liver fibrosis in mice to evaluate their feasibility and effectiveness as anti-liver fibrosis drugs.Part Ⅲ:Transcriptome sequencing and bioinformatics were used to analyze the changes in the mRNA expression profile of the LO-2 cell line stimulated by MSP or TGF-β1 to screen the potential signal pathways for MSP-induced hepatocyte epithelial-mesenchymal transition.Cell proliferation and migration experiments were used to clarify the effects of LPS or MSP stimulation on the phenotype of LO-2 cells;Western Blot and ELIS A techniques were used to determine the effects of LPS or MSP stimulation on the epithelial-mesenchymal transition and fibrotic protein expression of LO-2 cells.Finally,through targeted inhibition of MSP,RON or TGF-β1,the mechanism of MSP-RON pathway regulating the epithelial-mesenchymal transition of LO-2 cells was clarified.Result Part Ⅰ:Abnormally elevated serum MSP is an important serological marker for patients with liver fibrosis/cirrhosis and can be used to assess the prognosis of patients with liver cirrhosis.Abnormally activated MSP may play an important role in the pathological progression of liver cirrhosis,and its underlying mechanism may be related to TGF-β1.Part Ⅱ:The abnormal increase of serum MSP and the overexpression of RON in the liver are important pathological characteristics in the progression of liver fibrosis.The mechanism by which the MSP-RON signal axis regulates liver fibrosis may be related to the epithelial-mesenchymal transition mediated by TGF-β1.It is clear that targeting MSP or RON has potential value in the treatment of liver fibrosis.Part Ⅲ:The MSP-RON pathway can promote the transformation of liver cells into mesenchyme and promote the progression of fibrosis through the epithelial mesenchymal transition pathway.The epithelial-mesenchymal transition mediated by the MSP-RON pathway is regulated by the TGF-β/SMAD pathway.Conclusion Abnormal activation of the MSP-RON signal axis participates in the pathological progression of liver fibrosis and cirrhosis,and exerts biological effects through the TGF-β-dependent epithelial-mesenchymal transition pathway.Overexpressed MSP and RON are not only important biomarkers for liver fibrosis/cirrhosis and can be used to assess the prognosis of patients with liver cirrhosis,but also potential drug targets for the treatment of liver fibrosis and cirrhosis.