Oxidized Lipids in Cardiovascular Disease

描述(申请人提供)：氧化游离脂肪酸(Ox-FFA)对细胞有深远的影响。这些影响中的大多数是有害的和有利于动脉粥样硬化的。令人惊讶的是，它们还具有诱导过氧化氢酶等有益效果。这些可能是PPAR信号的一些“隐藏”效应，因为一些PPAR配体是过氧化氢酶(一种过氧化物体酶)的激活剂。另一方面，抗氧化酶的激活也可以代表细胞对氧化应激的防御。了解这些效应的基础将有助于我们确定在什么条件下抗动脉粥样硬化作用将战胜它们的促动脉粥样硬化作用。OX-FFA很难转运到细胞内，在酯化反应中的利用率也很低。因此，少量进入细胞的Ox-FFA可能更容易用于细胞内信号通路，即作为PPAR的配体，或被指定为降解途径。该提议的总体假设是：“细胞调节Ox-FFA的摄取和存在。进入细胞的少量Ox-FFA可以充当PPAR配体。它们在过氧化体中的降解将产生H202，从而解释了它们的毒性。Ox-FFA诱导抗氧化酶的产生可能是对H202的产生或通过PPAR。”目的1：确定与未氧化脂肪酸相比，Ox-FFA摄取较差的原因。我们认为，Ox-FFA的极性增加和/或可饱和的膜蛋白或结构域可能是导致Ox-FFA摄取不足的原因。通过化学修饰和膜改变，我们将确定Ox-FFA摄取的变化。我们还将确定Ox-FFA在细胞内的命运。目的2：测定产生H202的过氧化物体中Ox-FFA的潜在降解能力。我们将确定Ox-FFA在细胞内的降解情况，如H202和其他极性产物的生成，以此作为过氧体氧化的衡量标准。利用酰辅酶A氧化酶基因敲除小鼠，我们将确定Ox-FFA的作用是否归因于其影响过氧化体代谢的能力。我们还将演示Ox-FFA是否会在动物和细胞培养模型中诱导过氧化物酶。目的：确定细胞PPAR和非PPAR是否介导了细胞对Ox-FFA的反应。利用生化和分子方法，我们将确定和描绘PPAR的依赖和独立的Ox-FFA的作用。

DESCRIPTION (provided by applicant): Oxidized free fatty acids (Ox-FFA) have profound effect on cells. Most of these effects are deleterious and pro-atherogenic. Surprisingly, they also have beneficial effects such as induction of catalase. These could be some of the "hidden" effects of PPAR signaling as some of the PPAR ligands are known activators of catalase, a peroxisomal enzyme. On the other hand, the activation of antioxidant enzymes could also represent cellular defense to an oxidative stress. Understanding the basis of these effects would help us to determine conditions under which the anti-atherogenic effects would prevail over their pro- atherogenic effects. Ox-FFA are poorly transported into cells and poorly utilized for esterification reactions. Thus, small amounts of Ox-FFA that enter the cell might be more readily available for intracellular signaling pathways, i.e. as ligands for PPARs, or destined for degradation pathways. The overall hypothesis of the proposal is, "Cells regulate the uptake and presence of Ox-FFA. The small amounts of Ox-FFA that enter the cell could act as PPAR ligands. Their degradation in peroxisomes would generate H202 thus accounting for their toxicity. The induction of antioxidant enzymes by Ox-FFA might be in response to the generation of H202 or via PPARs". AIM 1: To determine why the uptake of Ox-FFA is poor as compared to that of unoxidized fatty acids. We propose that the increased polarity of Ox-FFA and/or a saturable membrane protein or domain might contribute to the poor uptake of Ox-FFA. Using chemical modifications and membrane alterations, we will determine the changes in the uptake of Ox-FFA. We will also determine the intracellular fate of Ox-FFA. AIM 2: To determine the potential degradation of Ox-FFA in the peroxisomes generating H202. We will determine the intracellular degradation of Ox-FFA such as generation of H202 and other polar products as a measure of peroxisomal oxidation. Using acyl CoA oxidase knock out mice, we will determine whether the effects of Ox-FFA could be attributed to its ability to affect peroxisomal metabolism. We will also demonstrate whether Ox-FFA, analogous to the fibrates would induce peroxisomes in animal and cell culture models. AIM 3: To determine whether cellular PPAR and non-PPAR mediated cellular responses to Ox-FFA. Using biochemical and molecular approaches, we will determine and delineate PPAR dependent and independent effects of Ox-FFA.