Analysis of Wild Type and hepatocyte-specific CD36 knockout (CD36LKO) mice liver Transcriptomes under high fat diet (HFD)

We generated hepatocyte-specific CD36 knockout (CD36LKO) mice to study in vivo effects of CD36 on de novo lipogenesis (DNL) under high fat diet (HFD). Lipid deposition and DNL were analyzed in primary hepatocytes isolated from CD36LKO mice or HepG2 cells with CD36 overexpression. RNA-sequence, co-immunoprecipitation and proximity ligation assay were carried out to determine its role in regulating DNL. Results: Hepatic CD36 expression was upregulated in NAFLD mice and patients, and CD36LKO mice exhibited attenuated HFD-induced hepatic steatosis and insulin resistance. We identified hepatocyte CD36 as a key regulator for DNL in the liver. Sterol regulatory element-binding protein 1 (SREBP1) and its downstream lipogenic enzymes such as FASN, ACCa and ACLY were significantly downregulated in the liver of HFD-fed CD36LKO mice, whereas overexpression CD36 stimulated insulin-mediated DNL and lipid droplet formation in vitro. Mechanistically, CD36 was activated by insulin and formed a complex with insulin induced gene-2 (INSIG2), that disrupts the interaction between SREBP cleavage-activating protein (SCAP) and INSIG2, thereby leading to the translocation of SREBP1 from ER to Golgi for processing. Furthermore, treatment with 25-hydroxycholesterol or betulin, molecules shown to enhance SCAP/INSIG interaction, reversed the effects of CD36 on SREBP1 cleavage. Overall design: CD36 KO vs. WT