Neuron-glia interaction - novel neural trophic factors and their molecular action mechanism -

在冯氏神经纤维瘤（NF1）提取物中检测到两种新型神经营养因子。其中之一，神经母细胞瘤生长因子（Mr<5 kDa），促进人神经母细胞瘤细胞的增殖和大鼠皮层神经元的存活和神经延伸，但与神经生长因子（NGF）或NGF样因子不同。另一种营养因子是神经胶质生长抑制剂（Mr=100 k），可抑制胶质瘤细胞系、星形细胞瘤、胶质母细胞瘤、少突胶质细胞瘤和神经鞘瘤的生长。这些因子似乎不是以前发现的细胞因子或生长因子，如白细胞介素、粒细胞集落刺激因子、NGF和成纤维细胞生长因子，在提取物中也检测到纤毛神经营养因子样活性。通过Blue-Toyopearl和DEAE-Sephacel柱层析和Butyl-Toyopearl高效液相层析，从神经纤维瘤提取物中纯化出一种新的内源性胶质细胞增殖和DNA合成多肽抑制剂gliostatin。羟基磷灰石和Mono Q.单克隆抗体针对部分纯化（羟基磷灰石步骤）的胶质抑制素吸附生长抑制活性，免疫化学方法在Western blot分析中显示推定的胶质抑制素带，但与已知的细胞动力学没有交叉反应。虽然该产物在Superdex 200柱层析上的表观Mr=100 k并具有抑制活性，但在Western blotting上的还原条件下，它在较低的表观Mr=50 k下迁移，表明天然胶质抑制素的同二聚体结构由50个KDa亚组分组成。Gliostatin是一种有效的生长抑制剂，在nM浓度下对所有神经胶质肿瘤细胞和神经胶质成熟因子（GMF）刺激的星状母细胞起作用，但对神经元细胞不起作用。

Two kinds of novel neural trophic factors were detected in von Recklinghausen neurofibroma (NF1) extracts. one of two, neuroblastoma growth factor (Mr<5 kDa), promotes the proliferation of human neuroblastoma cell and survival and neurite-extension of rat cortical neuron, but is distinct from nerve growth factor (NGF) or NGF-like factors. The other trophic factor is a glial growth inhibitor (Mr=100 k), which suppresses the growth of glioma cell lines, astrocytoma, glioblastoma, oligodendroglioma and Schwannoma. These factors do not appear to be previously identified cytokines or growth factors such as interleukins, granulocyte colony-stimu-lating factor, NGF and fibroblast growth factor, Ciliary neurotrophic factor-like activity was also detected in the extracts. Anovel endogenous polypeptide inhibitor of proliferation and DNA synthesis of glial cells, gliostatin, was purified from the extracts of neurofibroma by a procedure comprising column chromatography with Blue-Toyopearl and DEAE-Sephacel, and high-performance liquid chromatography with Butyl-Toyopearl, Hydroxylapatite and Mono Q. monoclonal antibody raised against partially purified (Hydroxylapatite step) gliostatin adsorbed the growth inhibitory activity of gliostatin and immunochemically visualized the putative gliostatin bands on Western blot analyses, but showed no cross-reactivity with known cytokinesis. Although the product showed an apparent Mr=100 k accompanied by an inhibitory activity on Superdex 200 column chromatography, it migrated at a lower apparent Mr=50 k under the reducing condition on Western blotting, indicating that a homodimeric structure of native gliostatin consisted of 50 KDa subcomponents. Gliostatin was a potent growth inhibitor acting at nM concentration against all glial tumor cells d glia maturation factor (GMF)-stimulated astroblasts but not neuronal cells.