O'Keeffe Gerard W, Dockery Peter, Sullivan Aideen M
Department of Neuroscience/Anatomy, Biosciences Research Institute, National University of Ireland Cork (NUIC), Cork, Ireland.
J Neurocytol. 2004 Sep;33(5):479-88. doi: 10.1007/s11068-004-0511-y.
Growth/differentiation factor 5 (GDF5) is a member of the transforming growth factor-beta superfamily that is expressed in the developing CNS, including the ventral mesencephalon (VM). GDF5 has been shown to increase the survival of dopaminergic neurones in animal models of Parkinson's disease. This study was aimed at characterising the effects of GDF5 on dopaminergic neurones in vitro. Treatment with GDF5 induced a three-fold increase in the number of dopaminergic neurones in embryonic day 14 rat VM cultures after six days in vitro. A significant increase was also observed in the numbers of astrocytes in GDF5-treated cultures. GDF5 treatment also had significant effects on the morphology of dopaminergic neurones in these cultures; total neurite length, number of branch points and somal area were all significantly increased after six days in vitro. Analysis of neurite length and numbers of branch points at each level of the neuritic field revealed that the most pronounced effects of GDF5 were on the secondary and tertiary levels of the neuritic field. The specific type I receptor for GDF5, bone morphogenetic protein receptor (BMPR)-Ib, was found to be strongly expressed in freshly-dissected E14 VM tissue, but its expression was lost with increasing time in culture. Accordingly, treatment with GDF5 for 24 h from the time of plating induced increases in the numbers of dopaminergic neurones, while treatment with GDF5 for 24 h after six days in vitro did not. This study shows that GDF5 can promote both the survival and morphological differentiation of VM dopaminergic neurones in vitro, lending support to its potential as a candidate dopaminergic neurotrophin for use in the treatment of Parkinson's disease.
生长/分化因子5（GDF5）是转化生长因子-β超家族的成员，在发育中的中枢神经系统中表达，包括腹侧中脑（VM）。在帕金森病动物模型中，GDF5已被证明可增加多巴胺能神经元的存活率。本研究旨在表征GDF5在体外对多巴胺能神经元的影响。在体外培养6天后，用GDF5处理可使胚胎第14天大鼠VM培养物中多巴胺能神经元的数量增加三倍。在GDF5处理的培养物中，星形胶质细胞的数量也显著增加。GDF5处理对这些培养物中多巴胺能神经元的形态也有显著影响；体外培养6天后，总神经突长度、分支点数量和胞体面积均显著增加。对神经突场各水平的神经突长度和分支点数量进行分析发现，GDF5的最显著作用是在神经突场的二级和三级水平。发现GDF5的特异性I型受体骨形态发生蛋白受体（BMPR）-Ib在新鲜解剖的E14 VM组织中强烈表达，但随着培养时间的增加其表达消失。因此，从接种时起用GDF5处理24小时可诱导多巴胺能神经元数量增加，而在体外培养6天后用GDF5处理24小时则不能。本研究表明，GDF5在体外可促进VM多巴胺能神经元的存活和形态分化，支持其作为治疗帕金森病的候选多巴胺能神经营养因子的潜力。
