CYTOLOGICAL STUDIES OF DEVELOPING AND MATURE NEURONS

描述(改编自申请人的摘要)移植到 中枢神经系统雪旺细胞促进轴突再生 以及脱髓鞘轴突的重新髓鞘形成。自体移植的实验研究 因此，从小神经活检组织中体外培养产生的人类干细胞可能 具有重要的临床应用价值。一种培养成人干细胞的方法 并通过移植到免疫缺陷的啮齿动物身上来测试它们的功能 是发展起来的。通过添加一个 生长因子、海藻氨酸和腺苷激活剂的组合 环化酶，Forsklin，但人类干细胞在12-14岁后似乎生长停滞 人口倍增和他们的髓鞘轴突的能力在 在有丝分裂原的作用下生长。这些观察表明，分子和 人干细胞的功能特性随着可溶性细胞的生长而改变 有丝分裂原在体外。建议进行实验来验证这一假设，并 描述人类干细胞特性的变化。第一，组织培养 HERG受体表达及受体介导信号的影响 将对转导进行评估。第二，福斯可林的作用机制 增强Hereglin的促有丝分裂作用以及长期接触 对于结合的有丝分裂原改变，将检测干细胞对Forskolin的反应。 第三，实验将测试人类SC生长受阻是否反映了 它们进入复制衰老状态。这些研究将 关注hereglin/forsklin激活衰老相关蛋白的能力 蛋白质、p53和p21。生长调节蛋白的磷酸化作用 蛋白质，pRb，将被测定。端粒缩短的作用将是 通过引入催化剂来评估和预防生长停滞 将端粒酶亚基转化为早期传代的人类干细胞进行检测。第四, 体外培养条件下人干细胞与轴突相互作用能力的变化 将对体内髓鞘形成能力的影响进行评估 以及为研究最早的SC轴突而开发的体外模型 互动：供应链的初始联系、识别和关联 与轴突表面相连。实验包括对附着力的评估 分子，N-钙粘蛋白和L1，以及SC组装An的能力 细胞外基质。这些研究探索了人类使用的潜力 SCS在临床上的应用，同时扩大了我们对SCS的认识 雪旺细胞的生物学和分子特性。

DESCRIPTION (Adapted from applicant's abstract) When transplanted into the central nervous system, Schwann cells (Scs) promote regeneration of axons and remyelination of demyelinated axons. Autologous transplantation of human SCs generated by growth in vitro from small nerve biopsies might thus be of significant clinical value. A procedure for growing adult human SCs and testing their function by transplantation into immune-deficient rodents was developed. SCs are stimulated to divide rapidly by the addition of a combination of the growth factor, heregulin, and an activator of adenylyl cyclase, forskolin, but human SCs appear to growth arrest after 12-14 population doublings and their ability to myelinate axons decreases after growth with mitogens. These observations suggest that the molecular and functional properties of human SCs are changed by growth with soluble mitogens in vitro. Experiments are proposed to test this hypothesis and to characterize changes in the properties of human SCs. First, tissue culture effects on expression of heregulin receptors and receptor-mediated signal transduction will be evaluated. Second, the mechanism by which forskolin potentiates the mitogenic effect of heregulin and whether prolonged exposure to combined mitogens alters the SCs response to forskolin will be examined. Third, experiments will test whether arrest of human SC growth reflects their entry into a state of replicative senescence. These studies will focus on the ability of heregulin/forskolin to activate senescence-related proteins, p53 and p21. Effect on phosphorylation of the growth-regulating protein, pRb, will be determined. The role of telomere shortening will be assessed and prevention of growth arrest by introduction of the catalytic subunit of telomerase into early passage human SCs will be tested. Fourth, changes in the human SC's ability to interact with axons by growth in vitro will be evaluated Effects on myelination capability in vivo will be examined and an in vitro model developed for study of the earliest SC-axon interactions: the initial contact, recognition, and association of the SC with the axonal surface. Experiments include an assessment of adhesion molecules, N-cadherin and L1, and on the ability of the SC to assemble an extracellular matrix. These studies explore the potential for use of human SCs in clinical applications, while expanding our knowledge of the biological and molecular properties of Schwann cells.