Mature Brain Astrocyte Functions in Health and Disease

描述（由申请人提供）：我们计划研究成熟星形胶质细胞的功能，星形胶质细胞是哺乳动物中枢神经系统中的主要一类神经胶质细胞。我们目前对未成熟星形胶质细胞的特性有了很多了解，这些星形胶质细胞可以很容易地从新生啮齿动物的大脑中分离出来并进行培养。对更成熟的星形胶质细胞的研究由于不能纯化它们而受到阻碍，并且因为这些更成熟的星形胶质细胞在培养中迅速死亡。最近，我们开发了一种方法，分离成熟的，原生质星形胶质细胞从出生后的小鼠大脑皮层。我们已经发现，与未成熟的星形胶质细胞不同，成熟的星形胶质细胞迅速发生凋亡，除非它们与内皮细胞一起培养。利用这种新的培养制备，我们建议开始研究成熟星形胶质细胞的功能。首先，我们将研究内皮细胞促进原生质星形胶质细胞存活的信号机制。其次，我们将研究从健康小鼠脑中纯化的成熟星形胶质细胞的功能，询问它们是否促进神经元存活，突触发生或髓鞘形成。第三，我们将询问成熟的星形胶质细胞本身是否可以诱导和维持血脑屏障，如果不能，其他神经细胞类型如周细胞或神经元是否与星形胶质细胞合作。最后，我们将研究健康和反应性星形胶质细胞之间的关系。我们将纯化反应性星形胶质细胞，并通过微阵列分析比较它们的功能以及它们的基因表达模式。然后，我们将研究正常星形胶质细胞被诱导成为反应性的机制，以及反应性星形胶质细胞表型是否稳定或可以被诱导恢复到正常表型。这些研究有可能揭示星形胶质细胞在健康和疾病中的神秘作用。例如，了解血脑屏障可能有助于我们开发将药物输送到大脑的新方法。了解反应性神经胶质增生也可能导致新的治疗方法，因为它有助于神经退行性疾病，中风，癫痫的病理生理学，并限制再生CNS修复。

DESCRIPTION (provided by applicant): We propose to investigate the functions of mature astrocytes, a major class of glial cells in the mammalian central nervous system. We presently know a great deal about the properties of immature astrocytes, which can be easily isolated from neonatal rodent brains and cultured. Study of more mature astrocytes has been hindered by the inability to purify them and because these more mature astrocytes rapidly die in culture. Recently we have developed a method to isolate mature, protoplasmic astrocytes from postnatal mouse cerebral cortex. We have found that unlike the immature astrocytes, the mature astrocytes rapidly undergo apoptosis unless they are cultured together with endothelial cells. Using this new culture preparation, we propose to begin to investigate the functions of mature astrocytes. First, we will investigate the signaling mechanisms by which endothelial cells promote protoplasmic astrocyte survival. Second, we will investigate the functions of mature astrocytes purified from healthy mouse brains, by asking whether they promote neuronal survival, synaptogenesis, or myelination. Third, we will ask whether mature astrocytes by themselves can induce and maintain the blood-brain barrier and, if not, whether other neural cell types such as pericytes or neurons collaborate with astrocytes. Finally, we will investigate the relationship between healthy and reactive astrocytes. We will purify reactive astrocytes and compare their functions as well as their gene expression patterns by microarray profiling. We will then investigate the mechanisms by which normal astrocytes are induced to become reactive and whether the reactive astrocyte phenotype is stabile or can be induced to revert to a normal phenotype. These studies have potential to shed new light on the mysterious role of astrocytes in health and disease. For instance, understanding the blood-brain barrier may help us to develop new ways to deliver drugs into the brain. Understanding reactive gliosis may also lead to new treatments, as it contributes to the pathophysiology of neurodegenerative diseases, stroke, epilepsy, and limits regenerative CNS repair.