BIOCHEMICAL STUDY OF MYELINATION AND DEMYELINATION

本申请的总体目标是研究生物化学和 多发性硬化（MS）脱髓鞘免疫学基础 实验性过敏性脑脊髓炎（EAE），以及生化 影响髓鞘形成和髓鞘再生的参数。 我们的重点是 鞘糖脂（GSL）在这些事件中的作用。 由于GSL是 主要位于细胞表面，并且已知会经历细胞- 具体的，发展调节的变化，他们作为优秀的 用于监测髓鞘形成期间发生的细胞事件的标记物， 脱髓鞘 它们在这方面的重要性进一步体现在： (a)发现有独特的糖脂抗原共同的， （B）某些GSL是强大的 免疫细胞生长和分化的调节剂。 的所述第一区域中 研究，一个主要目标是提供更多的生物化学数据髓鞘 分解，相关的神经胶质反应和髓鞘再生。 这是 通过开发几种新颖且高度敏感的技术， 用于分析特定细胞GSL组分的程序。 免疫 对MS的研究已经很广泛，有强有力的证据表明， 自身免疫机制可能在其发病机制中起重要作用。 疾病 参与髓磷脂的自身抗原， MS中的少突胶质细胞变性尚未明确定义。 我们 假设MS和EAE的炎性脱髓鞘可能是 由CNS髓鞘蛋白特异性自身反应性T细胞触发， 糖缀合物，并通过针对靶抗原的体液应答 特异性定位于内皮细胞和CNS。 体液 对内皮细胞的反应可能是血管通透性的原因 脱髓鞘前的变化。 这一假设将被测试， 体外和体内模型系统。 在第二个研究领域，我们 计划专注于合成半乳糖苷（GC），这是高度 富含髓磷脂 由于有两种类型的GC， 它们是由两种不同的半乳糖基转移酶合成的。 我们计划纯化这两种酶，并研究它们的亚细胞 定位，并阐明酶活性的调节 在分子生物学技术的发展过程中。 以来 半乳糖基转移酶明显存在于少突胶质细胞的血浆中 膜和髓鞘，我们建议，他们可能作为膜粘附 形成髓鞘多层结构的分子。 一个 了解半乳糖苷的合成和功能， 增强我们对髓鞘形成和髓鞘再生调节因子的认识。

The overall objective of this application is to study the biochemical and immunological basis of demyelination in multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE), as well as the biochemical parameters affecting myelination and remyelination. Our emphasis is placed on the role of glycosphingolipids (GSLs) in these events. Since GSLs are localized primarily on the cell surface and are known to undergo cell- specific, developmentally regulated changes, they serve as excellent markers for monitoring cellular events occurring during myelination and demyelination. Their importance in this regard is further underscored by: (a) the discovery that there are unique glycolipid antigens common to the nervous system and the endothelial cells, and (b) certain GSLs are powerful modulators of immune cell growth and differentiation. In the first area of research, a major goal is to provide additional biochemical data on myelin breakdown, the associated gliotic reactions, and remyelination. This is facilitated by the development of several novel and highly sensitive procedures for analyzing specific cellular GSL components. Immunological research in MS has been extensive, and there is strong evidence that an autoimmune mechanism may play an important role in the pathogenesis of this disease. The autoantigen(s) that are involved in myelin and oligodendroglial degeneration in MS have not been clearly defined. We hypothesize that the inflammatory demyelination in MS and EAE may be triggered by autoreactive T cells specific for CNS myelin proteins and glycoconjugates, and by humoral response against target antigens specifically localized in endothelial cells and the CNS. The humoral response against the endothelium may account for the vascular permeability change preceding demyelination. This hypothesis will be tested employing in vitro and in vivo model systems. In the second area of research, we plan to focus on the synthesis of galactocerebrosides (GC) which are highly enriched in myelin. Since there are two types of GC, the possibility exists that they are synthesized by two distinct galactosyltransferases. We plan to purify these two enzymes and to study their subcellular localization, and to elucidate the regulation of the enzyme activities during development by molecular biological techniques. Since galactosyltransferases are apparently found in oligodendroglial plasma membrane and myelin, we propose that they may function as membrane adhesion molecules for the formation of the multilamellar structure of myelin. An understanding of the synthesis and function of galactocerebrosides should enhance our knowledge on factors modulating myelination and remyelination.