Figure 5. Oxidative stress-induced Nrf2 activation triggers VLDLR overexpression in hepatocytes.

Primary mouse hepatocytes, or HepG2 cells, were exposed to complete DMEM medium containing hydrogen peroxide (H₂O₂) (100 µM), rotenone (100 nM), and 4-hydroxynonenal (4-HNE) (20 µM), respectively, for 6 hours. (A) Oxidative stress inducers increases VLDLR expression at both mRNA and protein levels. All values are denoted as means ± SD from three or more independent batches of cells. * p < 0.05. (B) N-acetylcysteine (NAC) prevents oxidative stress-induced VLDLR upregulation. Primary mouse hepatocytes were pretreated with NAC (5mM) for 2 hours before the addition of H₂O₂ (100 µM) or rotenone (100 nM). (C) Oxidative stress inducers lead to Nrf2 activation. All values were denoted as means ± SD from three or more independent experiments. * p < 0.05. (D) Nrf2 inducers increase VLDLR expression. Primary mouse hepatocytes were exposed to the culture medium containing sulforaphane (2 µM) or tBHQ (10 µM) for 8 hours. VLDLR gene expression and protein abundance were determined. All values were denoted as means ± SD from three or more independent experiments. * p < 0.05. (E) Nrf2 siRNA transfection abolishes VLDLR increases in response to oxidative stress inducers. Primary mouse hepatocytes were transfected with Nrf2 siRNA for 16 hours before the exposure to oxidative stress inducers. Whole cell lysates were collected for the detection of VLDLR protein.