Fibronectin containing extra domain A(EDA^+ FN),a functional glycoprotein participating in several cellular processes,correlates with chronic liver disease.Herein,we aim to investigate the expression and secretion of EDA^+ FN from hepatocytes in nonalcoholic fatty liver disease(NAFLD) and the underlying mechanisms.Circulating levels of EDA^+ FN were determined by ELISA in clinical samples.Western blotting and flow cytometry were performed on L02 and Hep G2 cell lines to analyze whether the levels of EDA^+ FN were associated with endoplasmic reticulum(ER) stress-related cell death.Circulating levels of EDA^+ FN in NAFLD patients were significantly higher than those in control subjects,and positively related with severity of ultrasonographic steatosis score.In cultured hepatocytes,palmitate up-regulated the expression of EDA^+ FN in a dose-dependent manner.Conversely,when the cells were pretreated with 4-phenylbutyrate,a specific inhibitor of ER stress,up-regulation of EDA^+ FN could be abrogated.Moreover,silencing CHOP by sh RNA enhanced the release of EDA^+ FN from hepatocytes following palmitate treatment,which was involved in ER stress-related cell damage.These findings suggest that the up-regulated level of EDA^+ FN is associated with liver damage in NAFLD,and ER stress-mediated cell damage contributes to the release of EDA^+ FN from hepatocytes.
Scope: Circadian disorder and high-fat diet(HFD)can disturb lipid metabolism homeostasis and may promote the development of various metabolic diseases. The relationship between them is of great concern. This study aimed to explore the effects of Per1/Per2 double knockout(DKO)on hepatic lipid metabolism in mice under HFD and HFD with docosahexaenoic acid(DHA)substitution. Methods and results: Both wild type(WT)and DKO male C57BL/6 mice were fed with normal chow diet(CON), HFD, or HFD with DHA substitution(AO)for 15 weeks. At the end of the experiment, mice were sacrificed at zeitgeber time(ZT)0(7:00 am)or ZT12(7:00 pm). Pathological indicators were determined using histological and biochemical methods. Hepatic transcriptome sequencing analysis showed that DKO mice exhibited multiple dysfunctions in diurnal rhythm, drug metabolism, cell cycle, cancer pathways, and lipid metabolism. HFD had greater effects on fatty acid oxidation and cholesterol synthesis and metabolism in Per1-/-Per2-/-mice, which was improved by DHA substitution. Conclusions: Per1/Per2 played an important role in the circadian regulation of hepatic lipid metabolism, and DKO mice were more sensitive to HFD. DHA can improve circadian-related lipid metabolism disruption induced by HFD in mice.
Yiran BuSi ChenMengcheng RuanLibang WuHualin WangNa LiXiuju ZhaoXiaoli YuZhiguo Liu
