Human hepatoma Huh-7 cell culture models deficient in apolipoprotein B secretion

High plasma apolipoprotein B (apoB)-containing lipoproteins are both a biomarker and causal mediator of many metabolic diseases. Inhibition of apoB and MTP decreases plasma lipid levels but at a risk of lipid accumulation in tissues. Whole body knock out of MTP and APOB are embronically lethal. Therefore, we created a human hepatome cells line (Ako) deficient in APOB gene to understand the global consequences of APOB loss. APOB gene deletion significantly reduced apoB mRNA and protein levels in the Ako cells compared to control cells. These cells supported apoB48 secretion when transfected with apoB48 expression plasmids. These cells did not accumulate significant amounts of triglyceride. KEGG pathway analysis of RNA-Seq data showed a significant increase in DNA replication/repair pathway and complement/coagulation cascade in the Ako cells. The most downregulated pathways included the PI3k-Akt signaling and MAPK signaling pathways. Total proteome analysis of secretory proteins identifed Vitamin D binding protein as the most upregulated protein while apoB was the most dowregulated protein in these cells. Since both APOB and MTP are important part of the lipoprotein assmebly and secretion, we also perfrmed total transcriptome analysis for the MTP deficient Huh-7 (Mko-3) cells. We found differential expression of some the pathways in both Ako and Mko-3 cells such as DNA replication, base excision repair, steroid hormone biosynthesis and pathways reated to breast cancer. These cells may be useful in studying structure-function analysis of apoB peptides and to address the cellular consequences of disruptions in lipoprotein assembly and secretion. However; further detailed studies are needed to establish how apoB regulates these pathways