Loss of Small Valosin-containing Protein-Interacting Protein (SVIP) in Rat Hepatoma cells Causes Increased Intracellular Retention of Very Low-Density Lipoproteins (VLDL)
In the current study we have generated a CRISPR-Cas9 mediated SVIP knockout rat hepatoma cell line with the goal to further understand the functional role of SVIP in the complex process of VLDL transport and secretion. We observed that complete absence of SVIP protein results in enhanced retention of VLDL in the hepatoma cells. This was marked by both an increased expression of apoB100 protein and neutral lipid staining detected inside SVIP knockout (SVIP KO) cells. Furthermore, RNA sequencing studies of the SVIP KO hepatoma cells revealed a significant downregulation of genes within the peroxisome proliferator- activated receptor alpha (PPAR alpha) and the nuclear factor erythroid 2-related factor 2 (Nrf2) pathways, thereby affecting hepatic fatty acid (FA) metabolism. Most importantly, we observed that cells lacking SVIP demonstrated a substantial down regulation of another very important gene associated with FA metabolism, namely the liver fatty acid-binding protein (L-FABP). Additionally, the RNAseq data also reveals that the loss of SVIP thrusts the hepatoma cells into an acute phase response (APR) like state, with an increase in the expression of protein synthesis genes. Overall design: RNA-seq profiling of wildtype (WT) rat hepatoma cells (McARH-7777) and their CRISPR-Cas9 mediated SVIP knock out cells (KO)- untreated and treated with 0.4mM BSA-Oleic acid for 1 h and collected 24 h post treatment.