Astrocytes Play a Critical Role in the Pathology of EAE

星形胶质细胞在 EAE 病理学中发挥关键作用

• 批准号: 8824782
• 负责人: John Roland Bethea
• 金额: $ 8.33万
• 依托单位: DREXEL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-15 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8824782
• 关键词: Astrocytes; Play; Critical; Role; Pathology

Project Summary Multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) are believed to be initiated by T cell-mediated immune responses to myelin antigens. In recent years, however, a significant body of evidence has been compiled indicating the contribution of various cell populations within the central nervous system (CNS), such as microglia and astrocytes, to the development and progression of the disease. Nevertheless, the role of these cell types is far from being clearly understood. Chronic neuroinflammation and demyelination may also contribute to disease progression and chronic neurological deficits. In all these processes, in MS as well as in many other neurodegenerative diseases, astrocytes have been demonstrated to play an active role. Astrocytes respond to injury by becoming "reactive" or "gliotic", a complex cellular response whose functional significance is still poorly understood. For instance, reactive astrocytes release neurotrophins essential for neuronal survival and repair, and are also responsible for the production of pro-inflammatory molecules (cytokines, chemokines, growth factors, NO etc) growth-inhibitory molecules detrimental to functional recovery. Many of the processes occurring in reactive astrocytes are regulated by NF-kB, a key modulator of inflammation and secondary injury. The studies outlined in this proposal are designed to investigate the role of astroglial NF-kB in the pathophysiology of experimental autoimmune encephalomyelitis (EAE), taking advantage of a transgenic mouse model generated in our laboratory (GFAP-IkBa-dn mice) where NF-kB is functionally inactivated in cells expressing GFAP, such as astrocytes and non-myelinating Schwann cells. Preliminary data indicate that blocking astroglial NF-kB significantly reduces disease severity, improves functional recovery following EAE and reduces neuroinflammation and demyelination. This leads us to hypothesize that reactive astrocytes significantly contribute to disease progression and development of chronic neurological deficits in EAE and MS. This hypothesis will be tested in the four specific aims outlined below. While the results generated in our transgenic mice are very promising, the studies in Aim 1 will compare our GFAP-IkBa-dn mice to two additional mouse lines (described below) to confirm that the results obtained so far in our experimental model are uniquely associated with the astrocyte-specific inhibition of the NF-kB pathway. The first mouse line (73.12xffIKKb) is obtained by breeding a GFAP-Cre line developed in Dr. Sofroniew's laboratory to a floxed (f/f) IKKb line generated in the laboratory of Dr. Michael Karin. The second mouse line (GFAPCreERT2xffIKKb) is obtained by breeding a tamoxifen inducible GFAP-Cre line (CreERT2) developed in Dr. McCarthy's lab to the same floxed (f/f) IKKb line. In Aims 2 and 3 we will use the line(s) that provides the most robust clinical improvement over the corresponding control mice to further investigate the mechanisms at the basis of the protection provided by blocking astroglial NF-kB. Specifically, studies in Aim 2 will determine if there are differences in blood brain permeability and infiltration of leukocytes in the CNS of diseased WT and mutant mice. Studies in Aim 3 will determine the mechanisms through which inhibiting astroglial NF-kB promotes an anti-inflammatory response. Studies in this aim will focus on how inhibiting astroglial NF-kB alters T and B cell responses in the spinal cord. Finally, since demyelination is a hallmark of this disease and could be modulated by neuroinflammation, studies in Aim 4 will investigate the effect of the inhibition of astroglial-NF-kB on oligodendrocyte survival and demyelination. Our experiments will not only give insights into NF-kB signaling mechanisms, but also elucidate astrocyte responses under pathological conditions. Ultimately, our goal is to determine if interfering with these responses could be beneficial as a therapeutic strategy for MS and other neurological disorders.

项目摘要 多发性硬化（MS）及其动物模型实验性自身免疫性脑脊髓炎（EAE）是多发性硬化（MS） 据信是由T细胞介导的对髓鞘抗原的免疫应答引发的。近年来，A 大量的证据表明，细胞内的各种细胞群的贡献， 中枢神经系统（CNS），如小胶质细胞和星形胶质细胞，对神经系统发育和进展的影响。 疾病然而，这些细胞类型的作用远未被清楚地理解。慢性 神经炎症和脱髓鞘也可能导致疾病进展和慢性神经系统疾病 赤字在所有这些过程中，在MS以及许多其他神经退行性疾病中，星形胶质细胞 被证明发挥了积极作用。 星形胶质细胞通过变得“反应性”或“胶质化”对损伤作出反应，这是一种复杂的细胞反应， 功能意义仍然知之甚少。例如，反应性星形胶质细胞释放神经营养素 对于神经元存活和修复至关重要，并且还负责产生促炎性细胞因子。 分子（细胞因子、趋化因子、生长因子、NO等）生长抑制分子， 功能恢复在反应性星形胶质细胞中发生的许多过程都受到NF-κ B的调节，这是一个关键因素。 炎症和继发性损伤的调节剂。 本研究旨在研究星形胶质细胞NF-kB在神经胶质细胞凋亡中的作用。 实验性自身免疫性脑脊髓炎（EAE）的病理生理学，利用转基因 在我们实验室中产生的小鼠模型（GFAP-IkBa-dn小鼠），其中NF-kB在细胞中功能失活 表达GFAP的细胞，如星形胶质细胞和非髓鞘形成的雪旺细胞。初步数据表明 阻断星形胶质细胞NF-κ B可显著降低疾病严重程度，改善EAE后的功能恢复 并减少神经炎症和脱髓鞘。这让我们假设反应性星形胶质细胞 显著促进EAE中疾病进展和慢性神经功能缺损的发展， 女士这一假设将在下文概述的四个具体目标中得到检验。虽然我们的研究结果 转基因小鼠是非常有前途的，目的1中的研究将比较我们的GFAP-IkBa-dn小鼠和两个 另外的小鼠系（如下所述）以证实在我们的实验模型中迄今为止获得的结果 与星形胶质细胞特异性抑制NF-κ B通路有关。第一条鼠标线 （73.12xffIKKb）是通过将Sofroniew博士实验室开发的GFAP-Cre系育种为floxed（f/f） IKKb系在Michael Karin博士的实验室中产生。第二个小鼠系（GFAPCreERT 2xffIKKb）是 通过将McCarthy博士实验室开发的他莫昔芬诱导型GFAP-Cre系（CreERT 2）与 相同的floxed（f/f）IKKb线。在目标2和3中，我们将使用提供最强大临床功能的产品线 与相应的对照小鼠相比的改善，以进一步研究在 通过阻断星形胶质细胞NF-κ B提供保护。具体而言，目标2中的研究将确定是否存在 患病WT和突变体CNS中血脑渗透性和白细胞浸润的差异 小鼠目标3中的研究将确定抑制星形胶质细胞NF-κ B促进神经胶质细胞增殖的机制。 抗炎反应。这方面的研究将集中在抑制星形胶质细胞NF-κ B如何改变T和B细胞 脊髓的反应。最后，由于脱髓鞘是这种疾病的标志， 目的4中的研究将研究抑制星形胶质细胞-NF-κ B对神经炎症的影响， 少突胶质细胞存活和脱髓鞘。 我们的实验不仅将深入了解NF-κ B信号转导机制， 病理条件下星形胶质细胞的反应。最终，我们的目标是确定是否干扰这些 作为MS和其他神经系统疾病的治疗策略可能是有益的。