Curcumol inhibits ferritinophagy to restrain hepatocyte senescence through YAP/NCOA4 in non-alcoholic fatty liver disease.

OBJECTIVES: In recent years, cellular senescence has attracted a lot of interest in researchers due to its involvement in non-alcoholic fatty liver disease (NAFLD). However, the mechanism of cellular senescence is not clear. The purpose of this study was to investigate the effect of curcumol on hepatocyte senescence in NAFLD and the molecular mechanisms implicated. MATERIALS AND METHODS: LVG Golden Syrian hamsters, C57BL/6J mice and human hepatocyte cell line LO2 were used. Cellular senescence was assessed by analyses of senescence marker SA-ß-gal, p16 and p21, H3K9me3, γ-H2AX and telomerase activity. RESULTS: The results showed that curcumol could inhibit hepatocyte senescence in both in vivo and in vitro NAFLD models, and the mechanism might be related to its regulation of ferritinophagy and subsequent alleviation of iron overload. Moreover, overexpression of nuclear receptor coactivator 4 (NCOA4) weakened the effect of curcumol on ferritinophagy-mediated iron overload and cellular senescence. Furthermore, we demonstrated that curcumol reduced the expression of NCOA4 by Yes-associated protein (YAP). In addition, depression of YAP could impair the effect of curcumol on iron overload and cellular senescence. CONCLUSION: Our results clarified the mechanism of curcumol inhibition of hepatocyte senescence through YAP/NCOA4 regulation of ferritinophagy in NAFLD. These findings provided a promising option of curcumol to regulate cellular senescence by target YAP/NCOA4 for the treatment of NAFLD.

LncRNA MAYA promotes iron overload and hepatocyte senescence through inhibition of YAP in non-alcoholic fatty liver disease.

Although recent evidence has shown that hepatocyte senescence plays a crucial role in the pathogenesis and development of non-alcoholic fatty liver disease (NAFLD), the mechanism is still not clear. The purpose of this study was to investigate the signal transduction pathways involved in the senescence of hepatocyte, in order to provide a potential strategy for blocking the process of NAFLD. The results confirmed that hepatocyte senescence occurred in HFD-fed Golden hamsters and PA-treated LO2 cells as manifested by increased levels of senescence marker SA-ß-gal, p16 and p21, heterochromatin marker H3K9me3, DNA damage marker γ-H2AX and decreased activity of telomerase. Further studies demonstrated that iron overload could promote the senescence of hepatocyte, whereas the overexpression of Yes-associated protein (YAP) could blunt iron overload and alleviate the senescence of hepatocyte. Of importance, depression of lncRNA MAYA (MAYA) reduced iron overload and cellular senescence via promotion of YAP in PA-treated hepatocytes. These effects were further supported by in vivo experiments. In conclusion, these data suggested that inhibition of MAYA could up-regulate YAP, which might repress hepatocyte senescence through modulating iron overload. In addition, these findings provided a promising option for heading off the development of NAFLD by abrogating hepatocyte senescence.