柿子单宁调节NOX2/NOX4介导泡沫细胞形成的机制研究

The formation of macrophage foam cell via receptor mediated Ox-LDL uptake is the most important pathology hallmark of atherosclerosis. Although, NADPH-oxidase has pivotal role on macrophage-mediated oxidation of LDL, NADPH-oxidase-mediated intracellular LDL oxidation may be more important. However, pathological significance of intracellular LDL oxidation for foam cell formation and mediated effect of NADPH-oxidase have remained virtually ignored. Scavenging NADPH-oxidase-derived reactive oxygen species and inhibiting NADPH-oxidase expression are of great importance for preventing LDL oxidation and foam cell formation. On these grounds, we hypothesized that persimmon tannin can regulate the expression of NADPH-oxidase through the signal pathway, thereby reduces LDL oxidation and foam cell formation, thus plays protective role on arterial injury. .Under this assumption, apoE knockout mice and persimmon tannin which is major antioxidant effect component from persimmon will be used. With RNA interference and gene transfer techniques, regulatory mechanism of persimmon tannin on NADPH-oxidase expression and mediated effect of NADPH-oxidase on intracellular LDL oxidation and foam cell formation will be studied. Implementation of this research can not only confirm the regulatory mechanisms of persimmon tannin on NADPH-oxidase expression and foam cell formation and oxidation mechanism of intracellular LDL mediated by NADPH-oxidase, but also indicate the direction for comprehensive utilization of persimmon and development of persimmon processing industry.

受体介导Ox-LDL摄取后引起的巨噬细胞泡沫化是动脉粥样硬化的重要病理学标志。NADPH-oxdiase(NOXs)对巨噬细胞介导的LDL氧化具有关键作用，而NOXs介导的细胞内LDL氧化可能更为重要，但其介导效应和病理学意义至今仍被忽视。清除NOXs产生的ROS，同时抑制NOXs表达对防止LDL氧化和泡沫细胞形成意义重大。据此我们假设：柿子单宁能通过信号通路调节NOXs表达，进而减少LDL氧化和泡沫细胞形成，发挥其对血管病变的保护作用。根据假设，本研究拟采用apoE基因敲除小鼠，以资源丰富的柿子为原料，借助基因转染和RNA干扰技术，研究抗氧化功效成分柿子单宁对NOXs表达的调节机制以及NOXs对细胞内LDL和泡沫细胞形成的介导效应。本项目的实施，不仅能明确柿子单宁调节NOXs表达及泡沫细胞形成机制和NOXs介导细胞内LDL氧化机制，还对柿子综合利用和解决柿子产业开发难题具有重要指导意。

受体介导Ox-LDL摄取后引起的巨噬细胞泡沫化是动脉粥样硬化的重要病理学标志。本项目采用apoE基因敲除小鼠，分别用槲皮素和自制富含柿子单宁的提取物两种物质对动脉粥样硬化小鼠进行营养干预，研究了以上两种物质对动脉粥样硬化的预防作用，并通过动物实验探讨了以上两种物质对小鼠氧化应激、脂质代谢和炎症的调节作用。研究表明两种干预物对小鼠动脉粥样硬化硬化均有明确保护作用，且均能缓解高脂膳食引起的NOXs介导的氧化应激水平、高脂膳食引起的ox-LDL大量积累、受体介导脂质代谢紊乱和炎症反应。本研究还发现槲皮素还可能通过改善高脂膳食诱导的自噬紊乱加速病灶部位ox-LDL降解排出，柿子单宁还可能通过上调肝脏FGF21表达缓解高脂膳食引起的肝脏脂质积累和通过调节巨噬细胞极化减少脉粥样硬化巨噬细胞的分化。本研究初步明确的柿子单宁对动脉粥样硬化的保护作用和相关机制，并提出NOX4在动脉粥样硬化发病进程中可能具有适应性保护作用，还提出溶酶体-自噬机制介导的ox-LDL降解可能在动脉粥样硬化发病进程中扮演重要作用。