Transport of Lipoprotein Lipase by Heparan Sulfate Proteoglycans

性状（由申请方提供）：脂蛋白脂肪酶是外周循环中负责水解富含甘油三酯脂蛋白的关键酶。细胞，如心肌和骨骼肌细胞、巨噬细胞和脂肪细胞合成并分泌脂蛋白脂肪酶。然后穿过将这些细胞与组织中的微血管分离的基底膜。酶被转运穿过内皮细胞到达其在内皮管腔上的作用位点。有证据表明，转运依赖于脂蛋白脂肪酶结合硫酸乙酰肝素蛋白多糖。然而，这些研究是在主动脉内皮细胞中进行的，其不具有生理学相关性，并且未确定活性硫酸乙酰肝素蛋白聚糖的鉴定。我们推测，特定的硫酸乙酰肝素蛋白聚糖驱动脂蛋白脂肪酶从内皮的近腔侧转运到其作用部位的腔侧。我们打算通过三个具体目标来检验这一假设：首先，我们将确定相关的心脏内皮细胞硫酸乙酰肝素蛋白聚糖与脂蛋白脂酶相互作用。接下来，我们将测试脂蛋白脂酶跨心脏内皮细胞的转运是否依赖于硫酸乙酰肝素蛋白聚糖。最后，我们将测试脂蛋白脂肪酶是否利用硫酸乙酰肝素蛋白聚糖进行体内运输，使用硫酸乙酰肝素生物合成或蛋白聚糖核心蛋白突变的小鼠。 公共卫生相关性：心血管疾病是美国的主要死亡原因。脂蛋白脂酶的表达、转运或功能受损可导致高脂血症、动脉粥样硬化和其他心血管疾病。这些研究将更好地定义硫酸乙酰肝素蛋白聚糖在脂蛋白脂肪酶运输中的作用，并将提供对体内硫酸乙酰肝素蛋白聚糖-脂蛋白脂肪酶相互作用受损的后果的深入了解。

DESCRIPTION (provided by applicant): Lipoprotein lipase is the critical enzyme responsible for the hydrolysis of triglyceride-rich lipoproteins in the peripheral circulation. Cells, such as cardiac and skeletal myocytes, macrophages, and adipocytes synthesize and secrete lipoprotein lipase. It then traverses the basement membrane separating these cells from the microvasculature in the tissue. The enzyme is transported across the endothelial cells to its site of action on the lumen of the endothelium. Evidence suggests that transport depends on lipoprotein lipase binding to heparan sulfate proteoglycans. However, these studies were done in aortic endothelial cells, which are not physiologically relevant, and the identification of the active heparan sulfate proteoglycans was not determined. We hypothesize that specific heparan sulfate proteoglycans drive the transport of lipoprotein lipase from the abluminal side of the endothelium to its site of action on the luminal side. We intend to test this hypothesis through three specific aims: First, we will identify the relevant cardiac endothelial cell heparan sulfate proteoglycans that interact with lipoprotein lipase. Next, we will test if lipoprotein lipase transport across cardiac endothelial cells depends on heparan sulfate proteoglycans. Finally, we will test if lipoprotein lipase utilizes heparan sulfate proteoglycans for transport in vivo using mice bearing mutations in heparan sulfate biosynthesis or proteoglycan core proteins. PUBLIC HEALTH RELEVANCE: Cardiovascular disease is the leading cause of death in the United States. Impairments in the expression, transport, or function of lipoprotein lipase can lead to hypertriglyceridemia, atherosclerosis, and other cardiovascular diseases. These studies will better define the role of heparan sulfate proteoglycans In the trafficking of lipoprotein lipase and will provide insight into the consequences of impaired heparan sulfate proteoglycan- lipoprotein lipase interactions in vivo.