| First Author | VerHague MA | Year | 2013 |
| Journal | Arterioscler Thromb Vasc Biol | Volume | 33 |
| Issue | 11 | Pages | 2501-8 |
| PubMed ID | 24030551 | Mgi Jnum | J:222215 |
| Mgi Id | MGI:5644132 | Doi | 10.1161/ATVBAHA.113.301948 |
| Citation | VerHague MA, et al. (2013) Apolipoprotein A-IV expression in mouse liver enhances triglyceride secretion and reduces hepatic lipid content by promoting very low density lipoprotein particle expansion. Arterioscler Thromb Vasc Biol 33(11):2501-8 |
| abstractText | OBJECTIVE: Previous studies demonstrated that apolipoprotein A-IV (apoA-IV) promotes apoB lipoprotein-mediated triglyceride (TG) secretion in transfected enterocytes and hepatoma cells; however, evidence for a role in lipid transport in vivo is lacking. Using mouse models, we explored the role of apoA-IV in hepatic very low density lipoprotein-mediated lipid efflux under conditions that promote hepatic steatosis. APPROACH AND RESULTS: Hepatic steatosis, induced by either high-fat diet or enhanced de novo lipogenesis caused by transgenic overexpression of SREBP-1a (SREBP-1a(Tg)), was associated with up to a 43-fold induction of hepatic apoA-IV mRNA and protein levels. In both models, a positive linear correlation between hepatic TG content and apoA-IV mRNA abundance was observed (r(2)=0.8965). To examine whether induction of apoA-IV affected hepatic TG secretion, SREBP-1a(Tg) mice were crossed with Apoa4 knockout mice. With Triton blockade of peripheral lipolysis, SREBP-1a(Tg)/Apoa4 knockout mice demonstrated a 24% reduction in hepatic TG secretion rate, relative to SREBP-1a(Tg) controls, but no change in apoB production. Negative stain electron microscopy revealed a 33% decrease in the abundance of secreted very low density lipoprotein particles with diameters >/= 120 nm. Conversely, mice infected with a recombinant human apoA-IV adenovirus demonstrated a 52% increase in the hepatic TG secretion rate, relative to controls, a 38% reduction in liver TG content, and a 43% increase in large diameter (>/= 120 nm) very low density lipoprotein particles, with no change in apoB secretion. CONCLUSIONS: Hepatic steatosis in mice induces hepatic apoA-IV expression, which in turn promotes lipoprotein particle expansion and reduces hepatic lipid burden without increasing the number of secreted atherogenic apoB-containing lipoprotein particles. |
