Functional analysis of HGF and its family member (HLP): from the basic to the potential application to neural diseases

肝细胞生长因子作为一种原代肝细胞有丝分裂原首次被纯化，并在的研究中进行了分子克隆。1995年，我们的研究小组利用原代海马神经元确定了HGF是一种神经营养因子。在此，我们重点阐述了HGF在神经发育和一种神经退行性疾病--肌萎缩侧索硬化症(ALS)中的作用。在大脑皮层发育过程中，HGF和c-Met/HGF受体以协同的方式进行局部和顺序的调节。此外，在原代分离的神经细胞培养和大脑皮层切片培养中，HGF还促进了神经元的迁移和存活。提示HGF在大脑皮层的形成中起重要作用。为了探讨HGF在ALS中的作用，我们首先建立了以神经元特异性方式过度暴露HGF的转基因小鼠(HGF-TG)，并将HGF-TG与ALS转基因小鼠过度表达突变体SOD1(ALS-TG)交配。过量暴露肝细胞生长因子…的转基因小鼠More和突变型SOD1(HGF/ALS-TG)。显示ALS小鼠运动神经元死亡减轻，起病延迟，运动功能改善，寿命延长。组织学、免疫印迹、定量竞争RT-PCR分析和神经细胞原代培养研究表明，HGF通过抑制运动神经元caspase-1的诱导和阻止星形胶质细胞中谷氨酸转运体的减少而改善ALS。HGF样蛋白(HLP/MSP)是HGF HGF家族成员之一，其受体RON在神经系统中表达。然而，HLP在神经系统中的作用还不是很清楚。我们利用鸡背神经节外植体发现HLP作为神经营养因子。由RON的胞外区和胞外区与免疫球蛋白融合的嵌合受体(ROU-Fc)消除了HLP在鸡感觉神经节上的活性，如迁移和轴突生长促进活性。这是HLP作为神经营养因子的第一个证据。较少

Hepatocyte growth factor (HGF) was first purified as a mitogen for primary hepatocyte, and molecularly cloned in 1989. In 1995, our group identified HGF as a neurotrophic factor using primary hippocampal neurons. We here focused on the elucidation of the role of HGF both during neural development and in one of the neurodegenerative diseases, amyotrophic lateral sclerosis (ALS). During cortical development, HGF and c-Met/HGF receptor was regionally and sequentially regulated in a concerted fashion.In addition, HGF promoted neural migration and survival of cortical neurons, analyzed in primary dissociated neuroual culture and slice culture of cerebral cortex. These suggested the implication of HGF in cortical layer formation. To assess the role of HGF in ALS, we first generated trausgenic mice overexposing HGF in a neuron specific manner (HGF-Tg).HGF-Tg was mated with transgenic mice overrexpressing mutant SOD1 (ALS-Tg), transgenic mice model of ALS. Transgenic mice overexposing both HGF … More and mutant SOD1 (HGF/ALS-Tg). showed the attenuation of motoneuronal death, delayed onset, improved motor function and prolonged life span of ALS mice. Histological, western blotting, quantitative competitive RT-PCR analyzes together with primary culture study of neural cells revealed that HGF improves, ALS by attenuating induction of caspase-1 in motoneurons and by preventing reduction of gluamate transporter in astrocytes. These suggest the potential therapeutic activities of HGF on ALS and related disorders.HGF-like protein (HLP/MSP) is a family member of HGF HGF and its receptor Ron were expressed in the nervous system. However, function of HLP in the nervous system is not well understood. We found that HLP acts as a neurotrophic factor using chick dorsal ganglion explants. A chimeric receptor composed of extracellular and trausmembrane domains of Ron fused with immunoglobuline (Rou-Fc) eliminated activities of HLP on chick sensory ganglia, such as migration and neurite outgrowth promoting activities. This is the first evidence that HLP acts as a neurotrophic factor. Less