Discovery for the Target Molecules to Control. Glial Scar Formation after Spinal Cord Injury

脊髓损伤是中枢神经系统最严重的创伤之一，每年造成数千名新患者。从创新治疗方法的角度来看，适当控制“胶质瘢痕”是非常重要的，因为瘢痕被认为会中断再生轴突。在周围神经系统中，雪旺细胞是周围神经中的髓鞘形成细胞，它在损伤后大量增殖并占据损伤区域，损伤后可再生。再生轴突穿过“雪旺细胞密集区”。因此，本研究将重点放在控制中枢神经系统中的少突胶质前体细胞（oligodendrocyte precursor cells，oligodendrocyte），使其占据脊髓损伤区域，帮助轴突再生上。本研究首先建立了小鼠少突胶质细胞原代培养体系，通过体外实验揭示其分子功能。已知少突胶质细胞以不成熟的形式增殖， 关于我们 培养条件含有足够的生长因子。目前还不知道生长因子是否传递任何特定的效果，以保持细胞在未成熟的状态。从蛋白表达分析中，我们选择了众所周知的细胞周期促进分子Cyclin D1分子，因为其蛋白水平与少突胶质细胞的未成熟状态具有很强的相关性。通过克隆细胞周期蛋白D1，产生分子的突变形式，基因转移到细胞中并分析分化标记物，研究细胞周期蛋白D1在少突胶质细胞成熟中的分子功能。我们发现Cyclin D1除了具有细胞周期调控功能外，还具有独特的调控少突胶质细胞成熟的机制。在未来的研究中，我们计划将这些发现应用于脊髓损伤动物模型，以观察是否可以控制脊髓损伤后少突胶质细胞的增殖，防止胶质瘢痕的形成，并通过DNA微阵列分析来研究与少突胶质细胞未成熟状态相关的分子。本研究通过对小鼠少突胶质细胞的原代培养，初步鉴定出20个可能与少突胶质细胞成熟相关的基因。我们计划在未来探索每个分子的分子功能。少

Spinal cord injury is one of the most severe trauma in central nervous systems, resulting several thousand new patients every year. From the view point of innovating new therapeutic approach for this injury, the proper control of "Glial Scar" is very important because the scar is believed to interrupt regenerating axons. In peripheral nervous systems, which can regenerate after injury, Schwann cells, myelinating cell in peripheral nerve, proliferate after injury and they occupy the damaged area. The regenerating axons go though "Schwann cell packed area". Therefore, we put focus on controlling oligodendrocyte precursor cells, myelinating cells in central nervous systems, so that they occupy the damaged area in spinal cord and help regenerating axons.In this research project, we first worked on the establishment of primary culture of mouse oligodendrocyte, which enable us to reveal molecular function by in vitro experiments. Oligodendrocytes are known to proliferate in immature form if … More the culture condition contain enough growth factors. It is not known whether growth factors convey any specific effect to keep the cells in immature status. From the protein expression analysis, we chose Cyclin D1 molecule, well known cell cycle promoting molecule, because its protein level shows strong correlation with immature status of oligodendrocyte. Molecular function of Cyclin D1 on oligodendrocyte maturation is investigated by cloning Cyclin D1, generating mutant forms of the molecule, gene transfer to the cells and analyzing differentiation markers. We found that Cyclin D1 has distinct mechanism to control oligodendrocyte maturation apart from its cell-cycle regulating function. For the future studies, we are planning to introduce these finding to animal model of spinal cord injury to see whether we can control proliferating oligodendrocyte in after spinal cord injury and prevent glial scar formation.We also perform DNA microarray analysis to survey the molecules which is relevant to immature status of oligodendrocyte. Our primary culture of mouse oligodendrocyte is helpful and we could identified 20 genes which is possibly related to oligodendrocyte maturation. We are planning to explore molecular function of each molecules in the future. Less