M. LEPRAE-INDUCED CONTACT-DEPENDENT DEMYELINATION

描述（由申请人提供）：脱髓鞘导致长期神经功能障碍，是麻风和许多病因不明的神经退行性疾病（如多发性硬化症（MS）和格林-巴利综合征（GBS））共有的主要病理状态之一。然而，脱髓鞘的分子基础在很大程度上是未知的。我们认为，在这些经典的和传染性的神经退行性疾病的脱髓鞘过程中有共同的主题。具有周围神经脱髓鞘的传染性神经变性疾病的一个众所周知的例子是麻风病，其由无毒细菌麻风分枝杆菌引起。我们最近的研究表明，M。麻风可用作模型来剖析脱髓鞘的早期分子事件。我们发现M.麻风或其细胞壁组分与髓鞘形成的许旺细胞-轴突单位的接触足以以接触依赖性方式诱导显著的脱髓鞘，这不需要免疫应答。然而，这种代表脱髓鞘初始事件的髓鞘损伤的机制尚不清楚。为了研究这些，我们使用先前建立的大鼠髓鞘化雪旺细胞-神经元共培养系统和Rag-1 -/-敲除小鼠分别作为体外和体内模型。微阵列分析使用具有cRNA的Affyphin大鼠和小鼠基因芯片，所述cRNA从髓鞘化Schwann细胞-神经元共培养物和感染M.在麻风病中，我们显示（i）主要信号蛋白基因的显著上调，和（ii）髓鞘和突触蛋白和电压门控离子通道基因的下调。我们建议M.麻风病对雪旺细胞-轴突单位上的受体/分子的作用迅速诱导强烈的信号传导，其影响下游转录因子的激活和最终导致髓鞘损伤的基因表达。为了调查这些，我们将研究以下内容： (1)在M. teprae诱导的脱髓鞘， (2)早期脱髓鞘中信号通路和转录激活的表征;（3）非层粘连蛋白受体的鉴定和表征，如M。用于诱导信号传导和脱髓鞘的麻风靶点。 这些研究将为脱髓鞘和神经元功能障碍的早期分子事件在受体，信号传导，转录和基因水平提供新的见解，并将有助于开发新的诊断和治疗麻风病和其他神经退行性疾病，如MS和GBS的神经损伤。

DESCRIPTION (provided by applicant): Demyelination, which leads to prolonged neurological disability, is one of the central pathologic conditions that is shared by leprosy and many neurodegenerative diseases with unknown etiology, such as multiple sclerosis (MS) and Guillain-Barr syndrome {GBS). However, molecular basis of demyelination is largely unknown. We propose that there are common themes at the onset of demyelination process among these classical and infectious neurodegenerative diseases. One of the well-known examples of infectious neurodegenerative diseases with peripheral nerve demyelination is leprosy, which is caused by the non-toxic bacterium, Mycobacterium leprae. Our recent studies have shown that M. leprae can be used as a model to dissect the early molecular events of demyelination. We found that the binding of M. leprae or its cell wall components to myelinating Schwann cell-axon units is sufficient to induce significant demyelination in a contact-dependent manner, which does not require immune responses. However, the mechanism of such myelin damage, which represents initial events of demyelination, is unknown. To study these, we used previously established rat myelinating Schwann cell-neuron co-culture system and Rag-1 -/- knockout mice as in vitro and in vivo models respectively. Microarray analysis using Affymetrix rat and mouse GeneChips with cRNA prepared from myelinating Schwann cell-neuron-co-cultures and the Sciatic nerves iromRag-1-/- knockout mice infected with M. leprae, we showed (i) significant up-regulation of genes for major signaling proteins, and (ii) down-regulation of genes for myelin and synaptic proteins and voltage-gated ion channels. We propose that the attachment of M. leprae to the receptors/molecules on Schwann cell-axon units rapidly induce strong signaling that influence the activation of downstream transcription factors and gene expression that eventually lead to myelin damage. To investigate these, we will study the following: (1) Temporal gene expression at the onset of and during M. teprae-induced demyelination, (2) Characterization of signaling pathways and transcriptional activation in early demyelination, and (3) Identification and characterization of non-laminin receptors as M. leprae targets for induction of signaling and demyelination. These studies will provide novel insights into the early molecular events of demyelination and neuronal dysfunctions at receptor, signaling, transcriptional and gene levels, and will aid in developing new diagnostics and therapeutics for nerve injuries both in leprosy and other neurodegenerative diseases such as MS and GBS.