Regulation of oligodendrocyte differentiation by BMP

描述(申请人提供)：少突胶质细胞的分化 来自发育中的中枢神经系统的神经外胚层干细胞 空间上受到限制，似乎取决于当地的环境因素 暗示。这一规定可能取决于各种因素，其中一些是归纳的，如 如音速刺猬，以及其他压抑，如凹槽信号。为了 了解少突胶质细胞的发育并尝试提高恢复 在髓鞘脱髓鞘或脱髓鞘之后，重要的是要识别这些 并了解它们是如何相互作用的。 我们一直在研究一种可能的少突胶质细胞抑制因素 发育，骨形态发生蛋白(BMP)，转化成员 参与背部组织规范的生长因子β家族， 调节中枢神经系统发育的许多不同方面，并 也存在于成虫体内。我们在组织培养方面的研究表明，BMPs 2 4对少突胶质细胞谱系有阶段特异性影响。在 BMP抑制分化为先祖细胞或前体阶段 少突胶质细胞和促进星形胶质细胞生成。BMP失去此效果后 少突胶质细胞成熟。骨形态发生蛋白在体内对少突胶质细胞形成的影响 一直难以捉摸。我们已经获得了三种类型的基因敲除小鼠 使我们能够确定BMP在少突胶质细胞形成和 星形胶质形成。我们将采用特定于神经管的条件性基因敲除 最广泛表达的BMP受体，BMPR-IA，BMP-IB的敲除 受体和双基因敲除，其中两个受体都被删除。初步 体外产生的数据表明，正常的BMP介导的抑制 Bmpr-1a来源的培养物中少突胶质细胞的成熟被破坏 淘汰赛和双淘汰赛。BMP介导的星形胶质细胞发生仅被破坏 在暗示IA和IB功能冗余的双淘汰赛中 感受器。我们计划分析这三个突变体以确定其亲缘关系 每种I型受体的贡献以及I型受体的总体作用 骨形态发生蛋白信号的抑制。我们假设BMP的消除 体内信号会导致异位和/或过早出现 少突胶质细胞伴随较少的星形胶质细胞。我们将表演 三者的脑和脊髓切片的免疫组织化学研究 突变体和对照以及免疫印迹法检测体内 效果。然后我们将在体外培养这些动物的少突胶质细胞， 确定BMP如何调节少突胶质细胞分化和星形胶质细胞 队形。我们还将研究BMP通过可能的 下游介体，分化抑制因子中的ID蛋白家族。 我们的初步数据表明，在BMP突变体中ID的表达发生了变化。

DESCRIPTION (provided by applicant): The differentiation of oligodendrocytes from neuroectodermal stem cells in the developing central nervous system is spatially restricted and appears to depend on local factors for environmental cues. This regulation may depend on a variety of factors, some inductive, such as sonic hedgehog, and others repressive, such as notch signaling. In order to understand oligodendrocyte development and attempt to improve recovery following dysmyelination or demyelination, it is important to identify these factors and learn how they interact. We have been studying a possible repressive factors for oligodendrocyte development, bone morphogenetic protein (BMP), members of the transforming growth factor Beta family involved in specification of dorsal tissues, that modulate many diverse aspects of central nervous system development and are also present in the adult. Our studies in tissue culture have shown that BMPs 2 and 4 have stage-specific effects on the oligodendrocyte lineage. In the pre-progenitor or precursor stage, BMP inhibits differentiation to oligodendrocytes and promotes astrogliogenesis. BMP loses this affect after the oligodendrocyte matures. The effect of BMP on oligodendrogliogenesis in vivo has been elusive. We have obtained three types of knockout mice that will enable us to determine the role of BMP in oligodendrogliogenesis and astrogliogenesis. We will employ a neural tube-specific conditional knockout of the most widely expressed BMP receptor, BMPR-IA, a knockout of the BMP-IB receptor and a double knockout in which both receptors are deleted. Preliminary data generated in vitro indicates that the normal BMP-mediated suppression of oligodendrocyte maturation is disrupted in cultures derived from the Bmpr-la knockouts and double knockouts. BMP-mediated astrogliogenesis is only disrupted in the double knockouts suggesting a functional redundancy of the IA and IB receptors. We plan to analyze these three mutants to determine the relative contribution of each of the type I receptors as well as the overall effect of the inhibition of BMP signaling. We hypothesize that the elimination of BMP signaling in vivo will cause ectopic and/or premature appearance of oligodendrocytes concomitant with fewer astrocytes. We will perform immunohistochemistry on sections of brain and spinal cord from the three mutants and controls as well as western blotting to determine the in vivo effects. We will then culture oligodendrocytes from these animals in vitro and determine how BMP regulates oligodendrocyte differentiation and astrocyte formation. We will also look at signaling from BMP through a possible downstream mediator, the Id protein family of inhibitors of differentiation. Our preliminary data suggests that Id expression is altered in the BMP mutants.