Short-term tamoxifen administration improves hepatic steatosis and glucose intolerance through JNK/MAPK in mice

Nonalcoholic fatty liver disease (NAFLD) which is a leading cause of chronic liver diseases lacks effective treatment. Tamoxifen hasbeen proven to be the first-line chemotherapy for several solid tumors in clinics, however, its therapeutic role in NAFLD has neverbeen elucidated before. In vitro experiments, tamoxifen protected hepatocytes against sodium palmitate-induced lipotoxicity. Inmale and female mice fed with normal diets, continuous tamoxifen administration inhibited lipid accumulation in liver, andimproved glucose and insulin intolerance. Short-term tamoxifen administration largely improved hepatic steatosis and insulinresistance, however, the phenotypes manifesting inflammation and fibrosis remained unchanged in abovementioned models. Inaddition, mRNA expressions of genes related to lipogenesis, inflammation, and fibrosis were downregulated by tamoxifentreatment. Moreover, the therapeutic effect of tamoxifen on NAFLD was not gender or ER dependent, as male and female mice withmetabolic disorders shared no difference in response to tamoxifen and ER antagonist (fulvestrant) did not abolish its therapeuticeffect as well. Mechanistically, RNA sequence of hepatocytes isolated from fatty liver revealed that JNK/MAPK signaling pathwaywas inactivated by tamoxifen. Pharmacological JNK activator (anisomycin) partially deprived the therapeutic role of tamoxifen intreating hepatic steatosis, proving tamoxifen improved NAFLD in a JNK/MAPK signaling-dependent manner.

Oit3,a promising hallmark gene for targeting liver sinusoidal endothelial cells

Liver sinusoidal endothelial cells(LSECs)play a pivotal role in maintaining liver homeostasis and influencing the pathological processes of various liver diseases.However,neither LSEC-specific hallmark genes nor a LSEC promoter-driven Cre mouse line has been introduced before,which largely restricts the study of liver diseases with vascular disorders.

The role of the Notch signaling pathway in liver injury and repair

This review aims to compile recent advances regarding the significance of Notch signaling in different types of intrahepatic cells during liver injury and repair.The functions of Notch signaling in regulating cell development,fate decisions,and organ homeostasis have been widely acknowledged.Notch is also expressed and activated in hepatocytes,macrophages,liver sinusoidal endothelial cells,endothelial progenitor cells,and hepatic progenitor cells during the process of development,injury,inflammation,fibrosis,and carcinoma.During acute/chronic liver injury,Notch interacts with many signaling pathways that are involved in liver repair.Recent research,including ours,has confirmed the crucial role of Notch signaling in modulating the function of diverse intrahepatic cells during liver injury and reconstruction.Thus,Notch signaling may serve as a potential therapeutic target for liver diseases.