Yu Ji Min, Kim Jae Ho, Song Geun Sung, Jung Jin Sup
Department of Physiology, College of Medicine, Pusan National University, 1 Ga, Ami-Dong, Suh-Gu, Pusan, 602-739, Korea.
Mol Cell Biochem. 2006 Aug;288(1-2):17-28. doi: 10.1007/s11010-005-9113-3. Epub 2006 Apr 1.
Wnt signaling is implicated in the control of cell growth and differentiation during CNS development. These findings are based on studies of mouse and chick models. However, the action of Wnt signaling, at the cellular level, is poorly understood. In this study, we investigated the roles of Wnt-3a and Wnt-5a on differentiation and proliferation of postnatal neural progenitor cells (NPCs) in mice.NPCs were isolated from the subventricular zone (SVZ) of PN-1 and adult ICR mice. Plasmids containing active Wnt-3a or Wnt-5a were transfected to NPCs; their effects on the formation of neurospheres and differentiation into neuronal cells were then determined. Transfection of Wnt-3a and Wnt-5a plasmids promoted regeneration of neurospheres and differentiation into Map2-positive cells, and decreased differentiation into GFAP-positive cells. The conditioned media obtained from Wnt-3a or Wnt-5a transfected NPCs showed similar effects on differentiation of NPCs with cDNA transfection, although the magnitude of stimulatory effect was less than that by plasmid transfection. Wnt-3a and Wnt-5a transfection did not affect Brdu incorporation of neuronal or glial progenitors in differentiation media. Wnt-3a and Wnt-5a plasmid transfection and the treatment of Wnt-3a and Wnt-5a conditioned media increased beta-catenin levels in NPCs. Wnt-3a had a greater effect on beta-catenin levels than Wnt-5a. The PKC inhibitor completely blocked the Wnt-5a effect on neuronal differentiation in NPCs. These findings suggest that Wnt-3a and Wnt-5a each have distinct effects on the proliferation and differentiation of NPCs in postnatal mice.
Wnt信号传导与中枢神经系统发育过程中的细胞生长和分化调控有关。这些发现基于对小鼠和鸡模型的研究。然而，Wnt信号传导在细胞水平上的作用尚不清楚。在本研究中，我们调查了Wnt-3a和Wnt-5a对小鼠出生后神经祖细胞（NPCs）分化和增殖的作用。从出生后第1天的ICR小鼠和成年ICR小鼠的脑室下区（SVZ）分离出NPCs。将含有活性Wnt-3a或Wnt-5a的质粒转染到NPCs中；然后确定它们对神经球形成和分化为神经元细胞的影响。Wnt-3a和Wnt-5a质粒转染促进了神经球的再生并分化为Map2阳性细胞，同时减少了向GFAP阳性细胞的分化。从转染了Wnt-3a或Wnt-5a的NPCs获得的条件培养基对NPCs分化的影响与cDNA转染相似，尽管刺激作用的程度小于质粒转染。Wnt-3a和Wnt-5a转染不影响分化培养基中神经元或神经胶质祖细胞的BrdU掺入。Wnt-3a和Wnt-5a质粒转染以及Wnt-3a和Wnt-5a条件培养基处理增加了NPCs中的β-连环蛋白水平。Wnt-3a对β-连环蛋白水平的影响比Wnt-5a更大。PKC抑制剂完全阻断了Wnt-5a对NPCs神经元分化的影响。这些发现表明，Wnt-3a和Wnt-5a对出生后小鼠NPCs的增殖和分化各有不同影响。
