PPARgamma, Endothelial Inflammation, and Atherosclerosis

越来越多的人支持炎症在动脉粥样硬化的发展中起主要作用的观点。 过氧化物酶体增殖物激活受体(PPARGamma)是配体激活的转录因子，是核基因家族的一个亚家族。PPARγ激活剂抑制活化内皮细胞中黏附分子的表达，并显著减少单核/巨噬细胞向动脉粥样硬化斑块的归巢。我们发现，稳定的层流激活ERK5，并增加PPARγ转录激活。此外，利用新发现的PPARGamma片段的铰链-螺旋1区(Hin-H1片段)，特异性地破坏ERK5/PPARGamma相互作用并抑制激活的ERK5介导的PPARGamma激活，将为探索ERK5和PPARGamma相互作用在层流介导的抗炎效应中的具体作用提供一个很好的工具。根据我们令人兴奋的初步数据，ERK5的激活增加了PPARGamma的活性，这可能抑制了黏附分子的表达，我们假设层流通过增加PPARGamma的转录活性和降低内皮细胞中VCAM-1的表达来发挥抗炎调节剂的作用。为了证明PPARGamma转录活性(受ERK5调控)在内皮细胞Flow的动脉粥样硬化保护作用中的作用，我们提出了三个目标。目的：利用培养的内皮细胞，研究ERK5/PPAR-γ在肿瘤坏死因子-α诱导的核因子-kappaB、血管细胞黏附分子-1启动子激活及随后的血管细胞黏附分子-1表达中的作用。目的2：利用体外培养的完整主动脉器官，检测PPAR-γ和ERK5在炎症相关黏附分子表达中的作用。目的3：利用动脉粥样硬化模型，利用En-Face共聚焦显微镜检测体内内皮细胞ERK5、JNK、NF-kappaB的活化和VCAM-1的表达，并检测其作用。 内皮细胞ERK5在动脉粥样硬化形成中的作用。在目标1中，我们将向您展示 ERK5/PPAR-γ相互作用对Hin-H1调节层流介导的抗炎作用的重要性 重组腺病毒载体中的ERK5 siRNA。在目标2中，我们将利用器官培养系统，并确定 ERK5-PPARγ在完整血管中的流动。在目标3中，我们将在以动脉粥样硬化形成为特征的LDLR-/-敲除(KO)小鼠中使用内皮特异性结构性活性(CA)-MEK5或ERK5‘敲除。我们 预期CA-MEK5可抑制动脉粥样硬化形成，ERK5 KO可促进动脉粥样硬化形成。这些实验将 为PPARγ的抗炎作用和FLOW与ERK5活性相关提供了新的分子机制。

There is increasing support for the idea that inflammation plays a major role in the development of atherosclerosis. Peroxisome proliferator-activated receptors (PPARgamma) are ligand-activated transcription factors that form a subfamily of the nuclear gene family. PPARgamma activators inhibit adhesion molecules expression in activated endothelial cells and significantly reduce monocyte/macrophage homing to atherosclerotic plaques. We found that steady laminar flow activates ERK5, and increases PPARgamma transcriptional activation. In addition, to utilize the newly identified Hinge-helix 1 region of PPARgamma fragment (Hin-H1 fragment), which specifically disrupts ERK5/PPARgamma interaction and inhibits activated ERK5-mediated PPARgamma activation, will provide a great tool to explore the specific role of ERK5 and PPARgamma interaction in laminar flow-mediated anti-inflammatory effect. Based on our exciting preliminary data that ERK5 activation increases PPARgamma activity and that this may inhibit the expression of adhesion molecules, we hypothesize that laminar flow acts as an anti-inflammatory modulator by increasing PPARgamma transcriptional activity, and decreasing VCAM-1 expression in endothelial cell. To prove the contribution of PPARgamma transcriptional activity (which is regulated by ERK5) to the atheroprotective effect of flow in endothelial cells we propose three aims. Aim 1 : Using cultured endothelial cells, define the role of ERK5/PPARgamma on TNF-alpha induced NF-kappaB, VCAM-1 promoter activation and subsequent VCAM-1 expression. Aim 2: Using an ex vivo organ culture system of intact aorta, determine the role of PPARgamma and ERK5 in inflammation-related expression of adhesion molecules Aim 3: Using an atherosclerosis model, determine endothelial ERK5, JNK, NF-kappaB activation and VCAM-1 expression in vivo by using en face confocal microscopy, and detect the role of endothelial ERK5 in atherosclerosis formation using gain and loss of function mice. In aim 1 we will show the importance of ERK5/PPARgamma interaction to regulate laminar flow-mediated anti-inflammatory effect using Hin-H1 fragment and ERK5 siRNA in adenovirus vector. In aim 2 we will utilize the organ culture system, and determine the role of ERK5-PPARgamma in flow in intact vessels. In aim 3 we will use endothelial specific constitutively active(CA)-MEK5 or ERK5' knock out in LDLR-/- knock out(KO) mice, which has been characterized by atherosclerosis formation. We anticipate that CA-MEK5 will inhibit and ERK5 KO will promote atherosclerosis formation. These experiments will provide a new molecular mechanism for the anti-inflammatory effect of PPARgamma and flow associated with ERK5 activity.