Up-regulated HOTAIR induced by fatty acids inhibits PTEN expression and increases triglycerides accumulation in HepG2 cells
AbstractNon-alcoholic fatty liver disease
Non-alcoholic fatty liver disease (NAFLD) is characterized by hepatic lipid accumulation unrelated to excess alcohol intake, in which the hepatic expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is inhibited. Long non-coding RNA HOTAIR suppresses PTEN expression in hepatic stellate cells during liver fibrosis, and it is involved in liver lipid dysregulation. In this study, we evaluated whether the PTEN down-regulation and lipid accumulation in hepatic cells might be mediated by HOTAIR during the development of NAFLD. Free fatty acids (FFAs) treatment promoted triglyceride accumulation in HepG2 cells, significantly increasing HOTAIR expression and inhibiting PTEN expression (both at mRNA and protein levels).The effects on HOTAIR and PTEN expressions disappeared after withdrawal of the FFAs treatment. SiRNA-mediated HOTAIR knockdown prevented PTEN down-regulation and triglyceride accumulation in HepG2 cells treated with FFAs; and CAPE (an NF-κBp65 inhibitor) treatment prevented the HOTAIR up-regulation and PTEN down-regulation. FFAs could induce the up-regulation of HOTAIR in HepG2 cells probably dependent on the NF-κB signaling, and consequently suppress PTEN expression and promote triglyceride accumulation. Aberrant up-regulation of HOTAIR mediated by excessive circulating FFAs levels may be a crucial mechanism associated with liver steatosis.
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