Role of podoplanin in hepatic stellate cell activation and liver fibrosis / 临床肝胆病杂志

ABSTRACT

ObjectiveTo investigate the role and mechanism of podoplanin （PDPN） in hepatic stellate cell （HSC） activation and liver fibrosis. MethodsLiver biopsy samples were collected from 75 patients with chronic hepatitis B who attended Department of Infectious Diseases， Putuo Hospital Affiliated to Shanghai University of Traditional Chinese Medicine， for the first time from September 2019 to June 2022， and RT-PCR and immunohistochemistry were used to measure the expression of PDPN in liver tissue of patients in different stages of liver fibrosis. A total of 12 male C57/BL6 mice were randomly divided into control group and model group. The mice in the model group were given intraperitoneal injection of 10% CCl4， and those in the control group were injected with an equal volume of olive oil， for 6 weeks. HE staining and Sirius Red staining were used to observe liver histopathological changes； primary mouse liver cells were separated to measure the mRNA expression of PDPN in various types of cells； primary mouse HSCs were treated with PDPN protein， followed by treatment with the NF-‍κB inhibitor BAY11-708， to measure the expression of inflammatory factors in HSCs induced by PDPN. The independent-samples t test was used for comparison of normally distributed continuous data between two groups； a one-way analysis of variance was used for comparison between multiple groups， and the least significant difference t-test was used for further comparison between two groups. The Spearman correlation analysis was used to investigate data correlation. ResultsAs for the liver biopsy samples， there was a relatively low mRNA expression level of PDPN in normal liver， and there was a significant increase in the mRNA expression level of PDPN in liver tissue of stage S3 or S4 fibrosis （all P<0.001）. Immunohistochemical staining showed that PDPN was mainly expressed in the fibrous septum and the hepatic sinusoid， and the PDPN-positive area in S4 liver tissue was significantly higher than that in S0 liver tissue （t=8.892， P=0.001）. In normal mice， PDPN was mainly expressed in the hepatic sinusoid， and there was a significant increase in the expression of PDPN in CCl4 model mice （t=0.95， P<0.001）， mainly in the fibrous septum. RT-PCR showed a significant increase in the mRNA expression of PDPN in the CCl4 model mice （t=11.25， P=0.002）. Compared with hepatocytes， HSCs， Kupffer cells， and bile duct endothelial cells， hepatic sinusoidal endothelial cells showed a significantly high expression level of PDPN （F=20.56， P<0.001）. Compared with the control group， the primary mouse HSCs treated by PDPN protein for 15 minutes showed significant increases in the mRNA expression levels of the inflammation-related factors TNFα， CCL3， CXCL1， and CXCR1 （all P<0.05）， and there were significant reductions in the levels of these indicators after treatment with BAY11-7082 （all P<0.05）. ConclusionThere is an increase in the expression of PDPN mainly in hepatic sinusoidal endothelial cells during liver fibrosis， and PDPN regulates HSC activation and promotes the progression of liver fibrosis via the NF-κB signaling pathway.