ECM and the Differentiation/Plasticity of DA Neurons

描述(由申请人提供)：我们最近在动物中展示了 帕金森病模型，一种进行性神经退行性疾病 以黑质纹状体多巴胺能神经元变性为特征 有一个强大的增殖爆发的神经前体细胞对 多巴胺神经元的丧失。但是，这些单元格仍处于 未分化状态。我们也已经证明，为了应对退化 黑质中未损伤的多巴胺神经元的数量 多巴胺神经元能够通过延长侧支来弥补这种损失 轴突纤维。然而，这种补偿性反应会大大减弱。 随着年龄的增长。因此，基于这些先前的结果，我们提出了 进一步的实验旨在发现如何诱导细胞分化 多巴胺能祖细胞与损伤诱导的动物侧枝萌发 帕金森氏症的模型。整合素是细胞表面的受体，参与 细胞-基质和细胞-细胞黏附相互作用在盐器中的作用 在调节细胞增殖、存活和过程中的重要作用 外延生长。神经系统外的研究表明， 来自整合素-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 中枢神经系统表达的分子与生长因子共同作用 诱导神经前体细胞定位和分化。测试我们的 假设，我们建议表征哪些ECM分子在 中脑多巴胺能前体细胞退出的发育时间 细胞周期和对多巴胺能神经元命运的最终承诺。 同时，我们计划在不同的ECM上培养这些祖细胞 与成纤维细胞生长因子-2结合的底物和测定 这些细胞的命运是否受到控制。我们进一步假设 大脑发育，细胞外基质分子的表达 神经前体细胞向多巴胺能神经元分化的研究 下调监管。为了测试这一想法，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 在成熟动物中的祖细胞分化，我们建议测试 逆转录病毒载体感染诱导整合素的表达 未确定的祖细胞的数量将会诱导它们分化。最后，我们计划 为了检验ECM分子中与年龄相关的差异对 在支持或抑制侧枝萌发方面的作用。因此，我们计划培养 胚胎纹状体组织切片上的多巴胺神经元 不同年龄段的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.