Effect of FGF-9 on cultured neurons : novel approach for the treatment of neurodegenerative disorders

本实验观察了成纤维细胞生长因子-9对胚胎第17天大鼠基底前脑胆碱能神经元(BFCN)和胚胎第14天大鼠前角胆碱能神经元(AHCN)原代培养的影响。成纤维细胞生长因子-9可提高BFCN和AHCN中AChE阳性神经元的存活率，增大其平均胞体大小，并上调其胆碱乙酰转移酶(ChAT)活性。对BFCN而言，其促进ChAT的作用与神经生长因子(NGF)大致相当，但强于碱性成纤维细胞生长因子(BFGF)、睫状神经营养因子(CNTF)或胶质源性神经营养因子(GDNF)。同时加入成纤维细胞生长因子-9和神经生长因子可诱导极高的ChAT水平，提示成纤维细胞生长因子-9和神经生长因子可能通过不同的途径协同作用增强BFCN胆碱能特性。在培养细胞和成年大鼠脑切片的免疫细胞化学和原位杂交研究中，BFCN胞浆免疫染色和表达FGF9信使RNA，从而推测FGF9以自分泌和/或旁分泌的方式作用于BFCN。因此，我们得出结论，在阿尔茨海默病和肌萎缩侧索硬化症的治疗试验中，成纤维细胞生长因子-9可能是一个很有前途的候选药物。下一步是开发有效的方法将外源性成纤维细胞生长因子-9运送到中枢神经系统。我们将成纤维细胞生长因子-9与一些多胺偶联，这种成纤维细胞生长因子-9-多胺复合体可以通过体外的血脑屏障系统，但与多胺偶联后，其对BFCN或AHCN的神经营养作用有所减弱。建立成纤维细胞生长因子-9-多胺偶联的最佳条件的实验正在进行中。

We examined the effect of fibroblast growth factor (FGF)-9 on primary cultures of rat basal forebrain cholinergic neurons (BFCN) obtained at embryonic day 17 and anterior horn cholinergic neurons (AHCN) obtained embryonic day 14. FGF-9 enhanced survival of AChE-positive neurons, increased their mean soma size, and upregulated choline their acetyltransferase (ChAT) activity in BFCN and AHCN.For BFCN, The ChAT-promoting effect of FGF-9 was approximately as potent as that of nerve growth factor (NGF) and was greater than those of basic fibroblast growth factor (bFGF), ciliary neurotrophic factor (CNTF), or glia-derived neurotrophic factor (GDNF). Simultaneous addition of FGF-9 and NGF induced extremely high ChAT levels, suggesting that FGF-9 and NGF may enhance cholinergic properties in BFCN via different pathways that can act synergistically. In immunocytochemical and in situ hybridization studies in cultured cells and also in sections of adult rat brain, BFCN showed cytoplasmic immunostaining for FGF-9 and expressed FGF-9 messenger RNA ; thus, we concluded that FGF-9 acts on BFCN in an autocrine and/or paracrine manner. Thus, we conclude that FGF-9 may be a promising candidate for therapeutic trials in Alzheimer disease and amyotrophic lateral sclerosis.The next step is to develop effective methods to deliver exogenous FGF-9 into the central nervous system. We coupled FGF-9 with some polyamines and this FGF-9-polyamine complex can pass through in vitro BBB system ; however, the neurotrophic effect of FGF-9 on BFCN or AHCN was somewhat diminished after coupling with polyamine. Experiments to establish optimal condition for FGF-9-polyamine coupling are now underway.