Outgrowth of neurites from NIE-115 neuroblastoma cells is prevented on repulsive substrates through the action of PAK
Outgrowth of neurites from NIE-115 neuroblastoma cells is prevented on repulsive substrates through the action of PAK
复制标题
DOI：
10.1128/mcb.25.12.5226-5241.2005
复制
发表时间：
2005-06-01
影响因子：
5.3
通讯作者：
Lim, L
中科院分区：
文献类型：
--
作者：
Marler, KJM;Kozma, R;Lim, L
在中枢神经系统(CNS)中，受损轴突的再生受到胶质瘢痕的抑制，其中分泌的硫酸软骨素蛋白多糖(CSPG)和Tenascin排斥轴突和树突的前体突起的生长。在分化过程中，这些分子被认为形成了引导神经元到达正确目标的边界。在神经母细胞瘤NIE-115细胞中，血清饥饿或肉毒梭菌C3毒素抑制RhoA均可诱导层粘连蛋白上突起的生长。长出的神经突起避免与排斥底物CSPG或Tenascin交叉。这种回避反应在膜靶向和激酶失活形式的PAK的表达上被部分克服。在这些细胞中，内源性PAK亚型与肌动蛋白在不同的部位共存，α-PAK在细胞中心呈小簇分布，沿轴突分布，β-PAK和γ-PAK分别位于有膜褶皱和丝状足部的区域。当引入异构体特异性的N-末端PAK序列来干扰PAK功能时，当细胞含有γ-PAK衍生肽而不是相应的α-PAK或β-PAK衍生肽时，显著更多的突起交叉到CSPG上。因此，虽然抑制RhoA可以促进轴突生长，但克服伴随的排斥性引导反应将需要调节PAK活性。这些结果对中枢神经系统的修复过程具有治疗意义。
In the central nervous system (CNS), damaged axons are inhibited from regeneration by glial scars, where secreted chondroitin sulfate proteoglycan (CSPG) and tenascin repulse outgrowth of neurites, the forerunners of axons and dendrites. During differentiation, these molecules are thought to form boundaries for guiding neurons to their correct targets. In neuroblastoma NIE-115 cells, outgrowth of neurites on laminin could be induced by serum starvation or inhibition of RhoA by Clostridium botulinum C3 toxin. The outgrowing neurites avoided crossing onto the repulsive substrate CSPG or tenascin. This avoidance response was partially overcome on expression of membrane-targeted and kinase-inactive forms of PAK. In these cells, the endogenous PAK isoforms colocalized with actin in distinctive sites, alpha PAK in the cell center as small clusters and along the neurite shaft and beta PAK and gamma PAK in areas with membrane ruffles and filopodia, respectively. When isoform-specific N-terminal PAK sequences were introduced to interfere with PAK function, substantially more neurites crossed onto CSPG when cells contained a gamma PAK-derived peptide but not the corresponding alpha PAK-or beta PAK-derived peptide. Thus, while neurite outgrowth can be promoted by RhoA inhibition, overcoming the accompanying repulsive guidance response will require modulation of PAK activity. These results have therapeutic implications for CNS repair processes.