ECM and the Differentiation/Plasticity of DA Neurons

描述（由申请人提供）：我们最近在动物中显示 帕金森病模型，一种进行性神经退行性疾病， 其特征在于黑质纹状体多巴胺能神经元的变性， 神经前体细胞的大量增殖， 多巴胺神经元的丧失。然而，这些细胞仍然处于 未分化状态我们还表明，在对退化的反应中， 黑质多巴胺神经元的数量 多巴胺神经元能够通过延伸侧支来补偿损失 轴突纤维然而，这种补偿反应变得大大减弱， 随着年龄的增长。因此，基于这些先前的结果，我们建议 进一步的实验旨在发现如何诱导分化的 多巴胺能祖细胞与损伤诱导动物侧支发芽 帕金森病的模型整合素是细胞表面受体， 盐器官中细胞-基质和细胞-细胞粘附的相互作用， 在调节细胞增殖、存活和过程中的重要作用 结果神经系统以外的研究表明， 来源于整合素-ECM相互作用和可溶性生长因子的信号 是细胞分化所必需的。因此，我们假设ECM 在CNS中表达的分子与生长因子一起作用 以诱导神经祖细胞定型和分化。来测试我们 假设，我们建议表征哪些ECM分子在 中脑多巴胺能祖细胞离开大脑皮层的时间 细胞周期，并使其最终致力于多巴胺能神经元的命运。 同时，我们计划在不同的ECM上培养这些祖细胞， 基质与成纤维细胞生长因子-2（FGF-2）的组合，并确定 这些细胞的命运是否受到调控。我们进一步假设， 在大脑发育的过程中， 神经前体细胞向多巴胺能神经元的分化变得 下调。为了验证这个想法，我们计划培养中脑祖细胞， 在含有黑质的组织切片上， 成熟的动物因为我们的总体目标是能够诱导多巴胺能 在成熟动物的祖细胞分化，我们建议测试是否 通过逆转录病毒表达载体感染诱导整合素的表达 未定型祖细胞的分化将诱导它们的分化。最后，我们计划 为了验证ECM分子中与年龄相关的差异在细胞外基质中发挥作用的假设， 支持或抑制侧枝发芽。因此，我们计划培养 纹状体组织切片上的胚胎多巴胺神经元， 不同年龄组的MPTP小鼠。

DESCRIPTION (provided by the applicant): We have recently shown in animal models of Parkinson's disease, a progressive neurodegenerative disorder characterized by the degeneration of nigrostriatal dopaminergic neurons, that there is a robust proliferative burst of neuroprogenitor cells in response to the loss of dopamine neurons. However, these cells remain in an undifferentiated state. We have also shown that in response to the degeneration of dopamine neurons in the substantia nigra that the remaining un-injured dopamine neurons are able to compensate for the loss by extending collateral axonal fibers. However, this compensatory response becomes greatly attenuated with increasing age. Therefore, based on these previous results we propose further experiments designed to discover how to induce the differentiation of dopaminergic progenitor cells and injury-induced collateral sprouting in animal models of Parkinson's disease. Integrins are cell surface receptors involved in cell-matrix and cell-cell adhesion interactions in salt organs and play an important role in regulating cell proliferation, survival, and process outgrowth. Studies outside the nervous system indicate that an integration of signals derived from both integrin-ECM interactions and soluble growth factors are required for cellular differentiation. Thus, we hypothesize that ECM molecules expressed in the CNS in combination with growth factors act together to induce neural progenitor cell commitment and differentiation. To test our hypothesis, we propose to characterize which ECM molecules are expressed during the time in development when midbrain dopaminergic progenitors are exiting the cell cycle and making their final commitment to the dopaminergic neuronal fate. In parallel, we plan to culture these progenitor cells on different ECM substrates in combination with fibroblast growth factor-2 (FGF-2) and determine whether the fate of these cells is regulated. We further hypothesize that as the brain develops, the expression of ECM molecules required for the differentiation of neural progenitor cells into dopaminergic neurons becomes down-regulated. To test this idea we plan to culture midbrain progenitor cells on tissue slices containing the substantia nigra from either developing or mature animals. Since our overall goal is to be able to induce dopaminergic progenitor cell differentiation in mature animals, we propose to test whether the induced expression of integrins by retroviral expression vector infection of uncommitted progenitors will induce their differentiation. Finally, we plan to test the hypothesis that age-related differences in ECM molecules play a role in supporting or inhibiting collateral sprouting. Thus, we plan to culture embryonic dopamine neurons on striatal tissue slices collected from control and MPTP mice of different age groups.