The Role of Astroglial-NF--kB in SCI

描述(由申请人提供)：我们的研究计划调查星形胶质细胞，特别是星形胶质细胞-核因子？B在神经退行性疾病的病理生理学中的作用。本申请中提出的实验目标将测试两个目标，并基于大量的初步数据。为了支持我们的第一个目标，我们已经确定在损伤后少突胶质细胞死亡、氧化损伤和NADPH氧化酶活性显著减少。此外，基于已完成和部分证实的微阵列研究、初步的流式细胞术和免疫染色，我们已经确定，抑制星形胶质细胞-NF？B极大地改变了脊髓中的炎症环境，使得潜在的毒性免疫调节分子以及渗透的白细胞在受伤的TG小鼠中与受伤的WT小鼠相比发生了显著变化。关于第一个目标，我们假设星形胶质细胞介导的少突胶质细胞死亡依赖于设计一个强大的炎症环境，以及氧化途径和兴奋毒性之间的复杂相互作用。为了支持我们的第二个目标，我们有重要的初步数据，这些数据非常支持增强的寡头发生。首先，我们证明了我们的转基因小鼠在脊髓损伤后有明显更多的白质，这可能是由于减少了少突胶质细胞死亡(目标1)和/或少突胶质细胞的发生。我们还证明了TG小鼠在损伤后髓鞘基因/蛋白的表达增强，以及已知在寡头发生中重要的转录因子。已有研究表明，CXCL12(SDF-1)及其受体(CXCR4和CXCR7)支持抑制底物上的寡聚和突起延伸。已完成的基因芯片研究结果已得到定量RT-PCR和Western blotting的证实，结果表明，在脊髓损伤后的TG小鼠中，特异性免疫/炎症分子，如趋化因子及其受体(例如，CXCL12和CXCR4)在寡聚/再髓鞘形成和功能恢复期升高。关于我们的第二个目标，我们假设抑制星形胶质细胞-核因子？B促进了有利于寡聚和再髓鞘形成的环境。这些假设和我们的实验目标将在以下具体目标中得到检验。具体目的1：探讨氧化损伤在星形胶质细胞介导的少突胶质细胞死亡和脱髓鞘中的作用。特异性目的2：探讨炎症在星形胶质细胞介导的少突胶质细胞死亡和脱髓鞘中的作用。特异目的3：确定抑制星形胶质细胞核因子B对脊髓损伤后寡聚和再髓鞘形成有何影响。特异性目的4：探讨CXCL12和CXCR4在脊髓损伤后少发和再髓鞘形成中的作用。

DESCRIPTION (provided by applicant): Our research program investigates the role of astrocytes and in particular astroglial- NF?B in the pathophysiology of neurodegenerative disorders. The experimental aims proposed in this application will test two objectives and are based upon extensive preliminary data. In support of our first objective we have determined there is a significant reduction in oligodendrocyte death, oxidative injury and NADPH oxidase activity following injury. Furthermore, based upon completed and partially confirmed micro array studies, preliminary flow cytometry and immunostaining we have determined that inhibiting astroglial- NF?B greatly modifies the inflammatory environment in the spinal cord such that potentially toxic immunoregulatory molecules along with infiltrating leukocytes are significantly altered in injured TG mice relative to injured WT mice. With respect to the first objective we hypothesize that astrocyte mediated oligodendrocyte death is dependent upon engineering a robust inflammatory environment as well as complex interactions between oxidative pathways and excitotoxicity. In support of our second objective we have significant preliminary data that are very supportive of enhanced oligogenesis. First, we demonstrate there is significantly more white matter in our TG mice following SCI which could be due to reduced oligodendrocyte death (objective 1) and /or oligogenesis. We have also demonstrated there is enhanced myelin gene/protein expression in TG mice following injury, as well as transcription factors known to be important in oligogenesis. Finally it has been previously demonstrated that CXCL12 (SDF-1) and its receptors (CXCR4 and CXCR7) support oligogenesis and neurite extension on inhibitory substrates. Results from completed microarray studies that have been confirmed by quantitative RT-PCR and Western blotting have determined that specific immune/inflammatory molecules such as chemokines and their receptors (e.g., CXCL12 and CXCR4) are elevated in TG mice following SCI during periods of oligogenesis/remyelination and functional recovery. With respect to our second objective we hypothesize that inhibiting astroglial- NF?B promotes an environment that is favorable for oligogenesis and remyelination. These hypotheses and our experimental objectives will be tested in the following specific aims. Specific Aim 1: Investigate the role of oxidative injury in astrocyte mediated oligodendrocyte death and demyelination. Specific Aim 2: Investigate the role of inflammation in astrocyte mediated oligodendrocyte death and demyelination. Specific Aim 3: Determine what effect inhibiting astroglial- NF?B has on oligogenesis and remyelination following SCI. Specific Aim 4: Investigate the role of CXCL12 and CXCR4 in oligogenesis and remyelination following SCI.