The Effect Of Lipopolysaccharide On The Activation,differentiation,and Malignant Transformation Of Hepatic Progenitor Cells In Mice

Hepatic progenitor cells(HPCs)are bipotential stem cells that can differentiate into mature hepatocytes or biliary epithelial cells(BECs).They are considered as adult stem cells in the liver.In general,HPCs remains dormant.They are activated when a severe or chronic injury happens to the liver.Because of their properties,HPCs transplantation are thought to benefit the patients with end-stage liver disease.However,questions still remain unclear about how HPCs were activated,what could influence their function,as well as the exact effect of them in liver disease.Lipopolysaccharide(LPS)is the major component of the cell wall of all Cram-negative bacteria cells.During all types of hepatic disease,LPS will be storedin the liver owing to the disturbance of enteric flora and the damage to liver metabolic function.As for this,we suspected that LPS may alter the physiology of HPCs.In this study,we fed C57BL/J6 mouseDDCto induce pathological HPCs activation.For observing the influence of LPS on HPCs,we added antibiotic into drinking water to limit the gut-LPS.To get primary C57BL/J6 HPCs,we isolated E-cadherin~+HPCs from C57BL/J6 fetal livers through an immunomagnetic bead cell sorting system.In order to investigate the influence of LPS on HPCs,CCK8,flow cytometry cycle,colony-formation assay and sphere-formation assay were used;We built HPCs differentiation systems to observe the role of LPS on it;To test whether HPCs would undergo neoplastic transformation under LPS treatment,normal HPCs and LPS-treated HPCs were subcutaneously transplanted into nude mice.The results showed that:limitating the production of intestinal LPS could effectively reduce the activation ofHPCs and alleviate liver disease in mice.And we confirmed thatLPS enhanced the proliferation of HPCs and acceleratedthe cell cycle in vitro.Moreover,colony formation ability of HPCs was enhanced by LPS stimulating.And LPS blocked HPCs from differentiating into mature hepatocytes and forming a bile duct-liked structure in HPCs differentiation systems.More importantly,long-term treatment with LPS promoted tumorigenesis of HPCs in nude mice.Thus,we concluded that,as an important component of liver pathology microenvironment,LPSsignificantly influenced the activation and physiology of HPCs.LPS could promote aberrant proliferation of HPCs and restrict their normal differentiation.Furthermore,long-term exposure of HPCs to LPS increased the risk of tumour formation.