In vivo assessment of Gas6 to protect oligodendrocytes and enhance remyelination

Gas6 保护少突胶质细胞和增强髓鞘再生的体内评估

• 批准号: 7531284
• 负责人: BRIDGET SHAFIT-ZAGARDO
• 金额: $ 18.16万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7531284
• 关键词: 1-Phosphatidylinositol 3-Kinase; Age; Axon; Brain; Cell Death; Cell Maturation; Cells; Cessation of life; Coculture Techniques; Corpus Callosum; Cuprizone; Data; Demyelinating Diseases; Demyelinations; Disease; Event; Excision; Family; Functional disorder; Genes; Growth Factor; Human; Individual; Inflammation; Inflammatory; Injury; Laboratories; Life; Ligands; Modeling; Movement; Multiple Sclerosis; Mus; Neuraxis; Neurons; Oligodendroglia; Pathway interactions; Phase; Phosphoinositide-3-Kinase, Catalytic, Gamma Polypeptide; Public Health; Publishing; Pump; Rattus; Receptor Protein-Tyrosine Kinases; Recombinants; Recovery; Relative (related person); Role; Signal Pathway; Signal Transduction; Spinal cord injury; Testing; Time; Toxic effect; Toxin; Translational Research; Vitamin K; Week; Withdrawal; assault; base; cell injury; computerized data processing; feeding; fetal; growth arrest-specific protein 6; improved; in vivo; insight; member; mouse model; myelination; nervous system development; receptor; stressor

DESCRIPTION (provided by applicant): Identifying factors that support the viability of oligodendrocytes and enhance myelination is essential for a more complete understanding of normal CNS maturation, and the events following a demyelinating assault such as an inflammatory attack that occurs in Multiple Sclerosis. Toward that end, our laboratory initiated microarray studies to identify genes expressed in human fetal O4+ immunopanned oligodendrocytes at multiple gestational weeks. Among the cDNAs identified were members of the receptor tyrosine kinase family, Axl, Rse, and Mer. The ligand, vitamin K-dependent growth-arrest specific protein 6 (gas6), activates the Axl, Rse, and Mer receptors and protects against growth factor withdrawal and other stressors by signaling through the PI3 kinase/Akt survival pathway. Our recent studies with oligodendrocyte cultures, oligodendrocyte/DRG co-cultures, and the cuprizone model have supported our hypothesis that the gas6/Axl/PI3 kinase/Akt signaling pathway functions in oligodendrocyte survival. Also, this pathway has important relevance to central nervous system (CNS) development and disorders involving inflammation, and myelination. Our preliminary data demonstrate that the addition of recombinant human gas6 (rhgas6) to rat oligodendrocyte/DRG co-cultures enhances myelination of axons; and addition of the decoy Axl-Fc diminishes myelination relative to the untreated cultures and the rhgas6-treated cultures. In addition, deletion of the Axl receptor alters remyelination 3 weeks following the removal of cuprizone, an oligodendrocyte toxin fed to mice for 6 weeks prior to assessing remyelination. This proposal will investigate in vivo the role of rhgas6 in protecting oligodendrocytes from cell death, and enhancing remyelination within the cuprizone mouse model paradigm. The hypothesis to be tested in this proposal is that exogenous gas6 administration directly to the corpus callosum can protect oligodendrocytes from cuprizone toxicity; and enhance remyelination during the recovery phase following cuprizone withdrawal. A mini-pump will be utilized to administer rhgas6 at two different time points. In Specific Aim #1 we will determine whether direct administration of rhgas6 to the corpus callosum of wildtype (WT) C57BL6J mice 1.5 weeks after the initiation of cuprizone treatment protects oligodendrocytes from cuprizone-induced cell death at week 3.5, a time-point when oligodendrocyte cell loss is clearly detectable. In Specific Aim #2 we will determine whether following cuprizone withdrawal, direct administration of rhgas6 to the corpus callosum of WT mice for two weeks enhances oligodendrocyte maturation and remyelination. These studies will provide insight into signaling processes that protect oligodendrocytes from dysfunction and/or death, and perhaps aid in remyelination in vivo. These studies have potential for translational research in diseases such as Multiple Sclerosis and spinal cord injury. PUBLIC HEALTH RELEVANCE The ability to achieve successful myelination is a priority for movement and higher brain function. To obtain successful remyelination following injury would positively impact upon the public health of individuals of all ages and dramatically improve the quality of their lives. Based upon our published and ongoing studies demonstrating that growth arrest specific protein 6 (gas6) enhances oligodendrocyte survival, maturation, and possibly myelination, this timely study examining the role of rhgas6 in a mouse model of demyelination/remyelination should have implications for human demyelinating diseases.

描述（由申请人提供）：确定支持少突胶质细胞活力和增强髓鞘形成的因素对于更全面地了解正常的中枢神经系统成熟以及脱髓鞘攻击（如多发性硬化症中发生的炎症攻击）后的事件至关重要。为此，我们的实验室启动了微阵列研究，以鉴定在多妊娠周人类胎儿O4+免疫少突胶质细胞中表达的基因。在鉴定的cdna中，有受体酪氨酸激酶家族的成员，Axl， Rse和Mer。这种配体是维生素k依赖性生长抑制特异性蛋白6 (gas6)，它激活Axl、Rse和Mer受体，并通过pi3k /Akt生存途径发出信号，防止生长因子戒断和其他应激源。我们最近对少突胶质细胞培养、少突胶质细胞/DRG共培养和cuprizone模型的研究支持了我们的假设，即gas6/Axl/PI3激酶/Akt信号通路在少突胶质细胞存活中起作用。此外，该途径与中枢神经系统（CNS）的发育和包括炎症和髓鞘形成在内的疾病具有重要的相关性。我们的初步数据表明，在大鼠少突胶质细胞/DRG共培养中加入重组人gas6 （rhgas6）可增强轴突的髓鞘形成；与未处理的培养物和rhgas6处理的培养物相比，添加诱骗物Axl-Fc减少了髓鞘形成。此外，Axl受体的缺失在去除铜酮（一种少突胶质细胞毒素）3周后改变了髓鞘再生，铜酮是在评估髓鞘再生前6周喂给小鼠的。本研究将在cuprizone小鼠模型中研究rhgas6在保护少突胶质细胞免于细胞死亡和促进髓鞘再生中的作用。本研究要验证的假设是，外源性气体6直接给药于胼胝体可以保护少突胶质细胞免受铜酮毒性；并在停药后的恢复期加强髓鞘再生。将使用一个迷你泵在两个不同的时间点管理rhgas6。在Specific Aim #1中，我们将确定在铜酮治疗开始1.5周后，野生型（WT） C57BL6J小鼠的胼胝体中直接给予rhgas6是否可以保护少突胶质细胞免受铜酮诱导的3.5周时的细胞死亡，这是少突胶质细胞损失明显可检测到的时间点。在Specific Aim #2中，我们将确定在铜吡酮停药后，WT小鼠胼胝体直接给予rhgas6两周是否能促进少突胶质细胞成熟和髓鞘再生。这些研究将深入了解保护少突胶质细胞免受功能障碍和/或死亡的信号过程，并可能有助于体内的髓鞘再生。这些研究在多发性硬化症和脊髓损伤等疾病的转化研究中具有潜力。成功实现髓鞘形成的能力是运动和高级脑功能的优先事项。损伤后成功的髓鞘再生将对所有年龄个体的公共健康产生积极影响，并显著提高他们的生活质量。基于我们已发表的和正在进行的研究表明，生长抑制特异性蛋白6 （gas6）可以增强少突胶质细胞的存活、成熟和可能的髓鞘形成，这项及时的研究检查了rhgas6在小鼠脱髓鞘/再脱髓鞘模型中的作用，应该对人类脱髓鞘疾病有启示。