Shu Xiao, Nelbach Lisa, Ryan Robert O, Forte Trudy M
Center for Prevention of Obesity, Diabetes and Cardiovascular Disease, Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA.
Biochim Biophys Acta. 2010 May;1801(5):605-8. doi: 10.1016/j.bbalip.2010.02.004. Epub 2010 Feb 11.
Apolipoprotein A-V (apoA-V), secreted solely by the liver, is a low abundance protein that strongly influences plasma triglyceride (TG) levels. In vitro, in transfected hepatoma cell lines apoA-V is largely retained within the cell in association with cytosolic lipid droplets (LD). To evaluate if this is true in vivo, in the present study the amount of apoA-V in the plasma compartment versus liver tissue was determined in APOA5 transgenic (Tg) mice. The majority of total apoA-V ( approximately 80%) was in the plasma compartment. Injection of APOA5 Tg mice with heparin increased plasma apoA-V protein levels by approximately 25% indicating the existence of a heparin-releasable pool. Intrahepatic apoA-V was associated with LD isolated from livers of wild type (WT) and APOA5 Tg mice. Furthermore, livers from APOA5 Tg mice contained significantly higher amounts of TG than livers from WT or apoa5 knockout mice suggesting that apoA-V influences intrahepatic TG levels.
载脂蛋白A-V（apoA-V）仅由肝脏分泌，是一种低丰度蛋白，对血浆甘油三酯（TG）水平有强烈影响。在体外，在转染的肝癌细胞系中，apoA-V主要与胞质脂滴（LD）结合而保留在细胞内。为了评估在体内是否也是如此，在本研究中，测定了APOA5转基因（Tg）小鼠血浆部分与肝组织中apoA-V的量。总apoA-V的大部分（约80%）存在于血浆部分。给APOA5 Tg小鼠注射肝素可使血浆apoA-V蛋白水平提高约25%，表明存在可被肝素释放的池。肝内apoA-V与从野生型（WT）和APOA5 Tg小鼠肝脏分离的脂滴相关。此外，APOA5 Tg小鼠的肝脏比WT或apoA5基因敲除小鼠的肝脏含有显著更多的TG，这表明apoA-V影响肝内TG水平。
