CD44/HA Pathway in Regulation of Neural Stem Cell Fate

描述(由申请人提供)： 干细胞，无论是胚胎干细胞还是体细胞干细胞，在理论上都为人类疾病的组织再生和器官功能恢复带来了巨大的希望。特别是，人类神经干细胞(HNSCs)的纯化和鉴定已经显示出在神经修复和开发基于hNSC的新的移植策略用于治疗神经退行性疾病方面的潜力。然而，对局部微环境调节hNSCs命运的机制缺乏了解，反映了我们对基本干细胞生物学知识的空白，仍然是有效治疗的障碍之一。细胞外基质(ECM)是大脑神经源性微环境的复杂结构。细胞外基质的主要成分透明质酸(HA)除了提供结构外，还通过与其细胞表面受体CD44的相互作用发挥调节作用，CD44由hNSCs表达。微阵列分析表明，高分子量HA显著改变了24个基因的表达，至少有两个。MFRP(膜型卷曲相关蛋白)和ICDAP-1α(整合素细胞质结构域相关蛋白-1α)可以决定hNSCs的行为选择。这项K18培训拨款申请由伯纳姆研究所干细胞项目主任埃文·斯奈德博士赞助，旨在解决CD44/HA途径如何调控hNSC命运的问题。根据我们的初步数据，我们假设HA通过与hNSCs上表达的CD44相互作用并启动信号转导途径，从而导致基因表达差异和hNSCs行为的重新编程，从而参与神经源性调控网络。在特定的目标1中，我们将研究HA对hNSCs细胞骨架组织和MAPK磷酸化的影响。在特定的目的#2中，我们将检测HA对hNSC中MFRP和ICDAP-1α表达的影响，以及HA对MFRP和ICDAP-1α差异表达的影响是否由CD44介导。总体而言，除了提供培训机会外，这一建议还将使我们能够检验一个新的假说，并为进一步研究CD44/HA通路在调节hNSCs命运中的作用提供数据。

DESCRIPTION (provided by applicant): Stem cells, both embryonic and somatic, theoretically hold great promise for tissue regeneration and the restoration of organ function in human diseases. In particular, the purification and characterization of human neural stem cells (hNSCs) has shown potential for neural repair and the development of new hNSC-based transplantation strategies for the treatment of aspects of eurodegenerative disorders. However, a lack of understanding of the mechanisms by which the local microenvironment regulates the fate of hNSCs reflects a gap in our knowledge of fundamental stem cell biology and remains one of the obstacles to effective therapies. Extracellular matrix (ECM) contributes to the complex structure of the brain's neurogenic microenvironment. In addition to providing structure, hyaluronic acid (HA), a major component of the ECM, possesses a regulatory function via its interactions with CD44, its cell surface receptor, which is expressed by hNSCs. Micro array analysis suggests that high molecular weight HA significantly changes the expression of 24 genes, at least two. MFRP (membrane-type frizzled-related protein) and ICDAP-1alpha (integrin cytoplasmic domain-associated protein-1 alpha) can determine the behavioral choices of hNSCs. This K18 training grant application, sponsored by Dr. Evan Snyder, director of The Burnham Institute's Stem Cell Program, is designed to address the question of how the CD44/HA pathway regulates the fate of hNSCs. Based on our preliminary data, we hypothesize that HA contributes to the neurogenic regulatory network by interacting with CD44 expressed on hNSCs and initiating signal transduction pathways that subsequently result in differential gene expression and the reprogramming of hNSCs behavior. In Specific Aim #1, we will investigate the effect of HA on cytoskeleton organization and MAPK phosphorylation in hNSCs. In Specific Aim #2, we will examine the effect of HA on the expression of MFRP and ICDAP-1alpha and whether the effect of HA on the differential expression of MFRP and ICDAP-1alpha is mediated by CD44 in hNSCs. Overall, in addition to providing training opportunities, this proposal will allow us to test a novel hypothesis and to generate data for further studies on the role of the CD44/HA pathway in regulation of hNSCs fate.