Fig. 1: Expression of NEDD8 is positively associated with increased lipogenesis transcription factors and is involved in the development of hepatic steatosis.

a Dot plot of NEDD8 expression levels (ILMN_2058070 at probe), SREBP1c (ILMN_1695378 at probe), NR1H3 for LXRα (ILMN_1695378 at probe), and MLXIPL for ChREBP (ILMN_1722073 at probe) within HC and HS patients (upper). Correlation analysis of NEDD8 and SREBP1c, NR1H3, and MLXIPL expression in the livers of HC and HS patients (bottom panel). The y-axis represents log2 expression of genes and error bars show SEM. b Normal liver tissue and hepatic steatosis tissue were subjected to immunoblotting using antibodies to NEDD8, SREBP1c, and LXRα. Protein band intensity was analyzed using ImageJ and protein levels were normalized relative to β-tubulin. Normal liver (blue symbols), hepatic steatosis (red symbols); correlation analysis was then performed between NEDD8 and SREBP1c or LXRα (green symbols: SREBP1c vs. NEDD8 r² = 0.8588, black symbols: LXRα vs. NEDD8 r² = 0.7038). *P < 0.0001 (n = 10 per group). c SREBP1c–NEDD8 interactions were examined by immunoprecipitation experiments in HepG2 cells treated with OA (500 μM) for 24 h. d HEK293 cells were cotransfected with Flag-SREBP1c and His-NEDD8 or His-NEDD8ΔGG for 48 h and subjected to Ni²⁺ pull-down assay. Purified cells were analyzed by Western blotting. e Flag-SREBP1c plasmid was cotransfected with His-NEDD8 or Myc-SENP8 into HEK293 cells for 48 h, and proteins isolated using Ni²⁺ pull-down assay were analyzed by Western blotting.