Mechanisms in CNS myelination: Role of PD-Ialpha/ATX

描述（由申请人提供）：由基质细胞蛋白家族介导的反粘附涉及细胞转化为有利于与运动相关的细胞功能的粘附中间状态。尽管少突胶质细胞髓鞘形成过程中的各种机车事件，参与反粘附机制尚未得到表征。基于我们的初步数据，我们假设磷酸二酯酶-1 α/自分泌运动因子[PD-1 α/ATX（NPP-2）]是由少突胶质细胞释放的，作为细胞外基质（ECM）的一种迄今尚未表征的反粘附组分，其关键参与调节少突胶质细胞粘附和髓鞘膜形成。在具体目标1中，我们将研究金属蛋白水解活性在产生可溶性少突胶质细胞衍生的PD-1 α/ATX中的作用，因为我们已经表明这种II型跨膜蛋白的可溶性形式作为反粘附分子发挥作用，并且存在于CNS髓鞘形成的初始阶段。在具体目标2中，我们将确定与其他基质细胞蛋白相似的细胞因子相关机制在多大程度上有助于PD-1 alpha/ATX对少突胶质细胞的反粘附作用。在这些实验中，我们将确定整合素的参与、细胞骨架蛋白的分布和Rho-GTP酶对PD-1 α/ATX介导的反粘附的活化状态。在具体目标3中，我们将确定适当髓鞘膜形成直接依赖于PD-1 α/ATX基因表达水平的程度。在这些研究中，我们将分析PD-1 α/ATX过度表达和表达不足对少突胶质细胞体外生成髓鞘膜和体内髓鞘形成轴突的能力的影响，这些能力存在于髓鞘形成障碍小鼠突变体shiverer的脑中。此外，我们将产生和表征转基因小鼠，其中少突胶质细胞过度表达PD-1 α/ATX。总之，这些研究将提供新的见解的反粘附分子的作用，少突胶质细胞的功能，并可能提供新的目标，以改善治疗策略，旨在刺激髓鞘再生的病理条件下。

DESCRIPTION (provided by applicant): Counter-adhesion, mediated by the family of matricellular proteins, has been implicated in the transformation of cells into an intermediate state of adhesion that favors cellular functions related to locomotion. Despite a variety of locomotive events during myelin sheath formation by oligodendrocytes, the involvement of counter-adhesive mechanisms has not been characterized. We hypothesize, based on our preliminary data, that phosphodiesterase-1 alpha/autotaxin [PD-1 alpha/ATX (NPP-2)] is released by oligodendrocytes as a hitherto uncharacterized counter-adhesive component of the extracellular matrix (ECM) that is critically involved in regulating oligodendrocyte adhesion and myelin membrane formation. In specific aim 1, we will investigate the role of metalloproteolytic activities in the generation of soluble oligodendrocyte-derived PD-1 alpha/ATX, since we have shown that the soluble form of this type II transmembrane protein functions as a counter-adhesive molecule and is present during the initial stages of CNS myelination. In specific aim 2, we will determine the extent to which cytoskeleton-related mechanisms, similar to the ones observed for other matricellular proteins, contribute to PD-1 alpha/ATX's counter-adhesive effect toward oligodendrocytes. In these experiments, we will determine the involvement of integrins, the distribution of cytoskeletal proteins and the activation state of Rho-GTPases to PD-1 alpha/ATX-mediated counter-adhesion. In specific aim 3, we will determine the extent to which proper myelin membrane formation is directly dependent on PD-1 alpha/ATX gene expression levels. In these studies we will analyze the effect of PD-1 alpha/ATX over and under expression on the ability of oligodendrocytes to generate myelin membranes in vitro and to myelinate axons in vivo in the brain of the dysmyelinating mouse mutant shiverer. In addition, we will generate and characterize transgenic mice, in which oligodendrocytes over express PD-1 alpha/ATX. Taken together, these studies will provide novel insight into the role of counter-adhesive molecules for oligodendrocyte function and likely provide novel targets for improving therapeutic strategies designed to stimulate remyelination under pathological conditions.