Phospholipase D2 regulation of vascular smooth muscle cell migration

描述(由申请人提供)：血管平滑肌细胞(VSMCs)的迁移是动脉粥样硬化和血管成形术后再狭窄过程中的重要事件。细胞迁移是通过膜运输和细胞骨架重组的协调调节来实现的。虽然许多研究都集中在VSMC中细胞骨架重组的调控上，但对膜转运以及细胞骨架重组和膜转运在这些细胞迁移过程中的协调调控知之甚少。我们的初步数据表明，磷脂酶D2(PLD2)是磷脂酶D家族中的一个成员，它产生信号转导的脂磷脂酸(PA)，在VSMCs的迁移、细胞骨架重组和膜运输中发挥重要作用。利用脂质体下拉和质谱学的结合，我们还鉴定了一些新的PA结合蛋白，揭示了对PA细胞功能的新的机制见解。基于我们的发现，我们认为PLD2产生的PA协调调节VSMC迁移过程中的细胞骨架重组和膜运输。通过使用一些新的可用的试剂和一种独特的交叉学科的方法，包括分子和细胞生物学，脂质生物学，和动物模型，我们将研究PLD2调控VSMC体外迁移的机制，然后利用小鼠模型研究PLD2调控的细胞迁移在损伤诱导的血管重建中的作用。提出了三个目标。在目标1中，我们将研究PLD2在VSMC极化和迁移中的作用。在目标2中，我们将阐明PLD2控制的膜转运调节VSMC迁移的机制。在目标3中，我们将研究PLD2是否在体内调节血管重塑。

DESCRIPTION (provided by applicant): The migration of vascular smooth muscle cells (VSMCs) is an essential event during atherosclerosis and restenosis after angioplasty. Cellular migration is achieved through coordinated regulation of membrane trafficking and cytoskeletal reorganization. While many studies have focused on the regulation of cytoskeletal reorganization in VSMCs, little is known about the involvement of membrane trafficking and the coordinated regulation of cytoskeletal reorganization and membrane trafficking in the migration of these cells. Our preliminary data have suggested that Phospholipase D2 (PLD2), a member of the phospholipase D family that generates the signaling lipid phosphatidic acid (PA), plays important roles in the migration, cytoskeletal reorganization, and membrane trafficking in VSMCs. Using a combination of liposome pull-down and mass spectrometry, we also identified some new PA-binding proteins, which have revealed the novel mechanistic insights into the cellular functions of PA. Based on our findings, we propose that PLD2-generated PA coordinately regulate cytoskeletal reorganization and membrane trafficking during VSMC migration. By using some newly available reagents and a unique interdisciplinary approach including molecular and cell biology, lipid biology, and animal models, we will investigate the mechanisms by which PLD2 regulates VSMC migration in vitro, and then examine how PLD2-regulated cell migration contributes to injury-induced vascular remodeling using mouse models. Three aims are proposed. In Aim 1, we will examine the roles of PLD2 in the polarization and migration of VSMCs. In Aim 2, we will elucidate the mechanisms by which PLD2-controlled membrane trafficking regulates VSMC migration. In Aim 3, we will investigate if PLD2 regulates vascular remodeling in vivo.