M. LEPRAE-INDUCED CONTACT-DEPENDENT DEMYELINATION

麻风杆菌引起的接触依赖性脱髓鞘

• 批准号: 7016349
• 负责人: ANURA RAMBUKKANA
• 金额: $ 33.01万
• 依托单位: ROCKEFELLER UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7016349
• 关键词: Guillain Barre syndrome; Mycobacterium leprae; Schwann cells; bacteria infection mechanism; bacterial antigens; binding proteins; biological signal transduction; gene expression; genetically modified animals; glycolipids; human genetic material tag; laboratory mouse; laboratory rat; laminin; leprosy; microarray technology; molecular pathology; multiple sclerosis; myelinopathy; nerve injury; neural degeneration; pathologic process; protein binding; tissue /cell culture; transcription factor

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.

描述（由申请人提供）：脱髓鞘会导致长期神经功能障碍，是麻风病和许多病因不明的神经退行性疾病（例如多发性硬化症（MS）和格林-巴尔综合征（GBS））所共有的核心病理状况之一。然而，脱髓鞘的分子基础很大程度上未知。我们认为这些经典和传染性神经退行性疾病在脱髓鞘过程的开始时存在共同的主题。伴有周围神经脱髓鞘的传染性神经退行性疾病的众所周知的例子之一是麻风病，它是由无毒细菌麻风分枝杆菌引起的。我们最近的研究表明，麻风分枝杆菌可以作为模型来剖析脱髓鞘的早期分子事件。我们发现麻风分枝杆菌或其细胞壁成分与有髓鞘的雪旺细胞轴突单位的结合足以以接触依赖性方式诱导显着的脱髓鞘，这不需要免疫反应。然而，这种代表脱髓鞘初始事件的髓磷脂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。使用 Affymetrix 大鼠和小鼠 GeneChips 以及从有髓鞘雪旺细胞神经元共培养物和感染麻风分枝杆菌的坐骨神经 iromRag-1-/- 敲除小鼠制备的 cRNA 进行微阵列分析，我们显示 (i) 主要信号蛋白基因显着上调，以及 (ii) 髓磷脂和突触蛋白以及电压门控离子基因下调 渠道。我们认为，麻风分枝杆菌与雪旺细胞轴突单位上的受体/分子的附着迅速诱导强烈的信号传导，影响下游转录因子的激活和基因表达，最终导致髓磷脂损伤。为了研究这些，我们将研究以下内容： (1) M. teprae 诱导的脱髓鞘开始时和期间的时间基因表达， (2)早期脱髓鞘中信号传导途径和转录激活的表征，以及(3)作为麻风分枝杆菌诱导信号传导和脱髓鞘靶标的非层粘连蛋白受体的鉴定和表征。 这些研究将为受体、信号传导、转录和基因水平上的脱髓鞘和神经元功能障碍的早期分子事件提供新的见解，并将有助于开发针对麻风病和其他神经退行性疾病（如多发性硬化症和GBS）神经损伤的新诊断和治疗方法。