Lack of Nr2e1 expression in hepatocytes impaired cell survival and aggravated palmitate-induced oxidative stress

Purpose

Nuclear receptor subfamily 2 group E member 1 (Nr2e1) has been regarded as an essential regulator in neural stem cells. However, its function is still not clear in hepatocytes. This study aimed to clarify the effects of Nr2e1-deficiency in hepatocytes in lipotoxic conditions.

Materials/methods

Nr2e1-knockdown AML12 ​cells were generated by lentiviral vector transfection. The influences of Nr2e1-deficiency on hepatocyte survival were determined by cell cycle progression and cell apoptosis rate using flow cytometry. Real-time quantitative PCR and Western blot were used to examine the genes and protein expression related to apoptosis, lipid metabolism, and oxidative stress. Meanwhile, RNA sequencing was adopted in liver samples from Nr2e1-knockout (Nr2e1-KO) mice.

Results

Nr2e1 expression was observed with a significant decrease in AML12 ​cells after palmitic acid-stimulation. Knockdown of Nr2e1 in AML12 ​cells resulted in increased sensitivity to lipotoxicity, evidenced by a partial G0/G1 cell-cycle arrest and higher rates of cell apoptosis. Moreover, Nr2e1-knockdown AML12 ​cells presented increased gene expressions relative to lipid synthesis but decreased levels of β-oxidation related genes. Lack of Nr2e1 augmented palmitate-induced oxidative stress in hepatocytes. In vivo, differential genes in Nr2e1-KO mice liver were enriched in pathways associated with liver regeneration and cell proliferation.

Conclusions

This study indicated that hepatocytes lacking Nr2e1 were more susceptible to lipotoxic-mediated damage. Nr2e1 may serve as a potential target for the development of novel therapies for lipotoxicity-induced liver injury.