Glowacka D, Ginty D D, Wagner J A
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts.
J Neurosci Res. 1992 Feb;31(2):263-72. doi: 10.1002/jnr.490310207.
A126-1B2 cells, a PKA (cAMP-dependent protein kinase)-deficient variant of PC12 cells, but not parental PC12 cells, form processes within 15-30 min of exposure to both nerve growth factor (NGF) and activators of protein kinase C when grown on tissue culture plastic (Glowacka and Wagner, J Neurosci Res 25: 453-462, 1990). Time-lapse microscopy has demonstrated that these processes are formed by a novel mechanism, i.e., rapid movement of the cell body away from a point of attachment, which morphologically resembles a growth cone. These "fast" neurites are attached to the substratum at a number of points, which display membrane activity in the form of active ruffling and the extension of filopodia and membrane pleats. Thus, these processes are formed by a mechanism distinct from that used by PC12 and other neuronal cells to form processes in culture. Wild-type PC12 cells also migrate and form fast neurites in response to a combination of NGF and phorbol 12-myristate 13-acetate (PMA), when they are grown in conditioned media or plates, suggesting that a secreted factor that can bind to the substratum is essential for the rapid formation of these neurites. Similarly, wild-type PC12 cells grown on a laminin-coated substratum also migrate and form "fast neurites" in response to a combination of NGF and PMA. This rapid migration is attenuated by an anti-alpha 1, beta 1-integrin antisera, implicating a laminin-integrin interaction; and it is inhibited by alpha-lactalbumin, suggesting an involvement of a beta 1,4 galactosyltransferase in the response. The formation of fast neurites is not dependent on concurrent protein synthesis, but it is inhibited by lithium, cytochalasin D, and methylthioadenosine or pretreatment of cells with NGF. Thus PC12 cells grown on the appropriate substrate have the ability to migrate rapidly and thereby form neuron-like processes within minutes of exposure to NGF and PMA. This morphological response to a combination of agents may provide an alternative means by which nerve cells form connections. Alternatively, it may reflect a mechanism that facilitates cellular migration during developmental processes.
A126 - 1B2细胞是PC12细胞的一种蛋白激酶A（cAMP依赖性蛋白激酶）缺陷型变体，当在组织培养塑料上生长时，它在暴露于神经生长因子（NGF）和蛋白激酶C激活剂的15 - 30分钟内会形成突起，而亲代PC12细胞则不会（Glowacka和Wagner，《神经科学研究杂志》25: 453 - 462，1990）。延时显微镜观察表明，这些突起是通过一种新机制形成的，即细胞体从附着点快速移动，在形态上类似于生长锥。这些“快速”神经突在多个点附着于基质，这些点呈现出活跃的褶皱、丝状伪足延伸和膜褶等形式的膜活动。因此，这些突起的形成机制与PC12细胞和其他神经元细胞在培养中形成突起的机制不同。当野生型PC12细胞在条件培养基或平板上生长时，它们也会对NGF和佛波醇12 - 肉豆蔻酸酯13 - 乙酸酯（PMA）的组合做出迁移并形成快速神经突的反应，这表明一种能与基质结合的分泌因子对于这些神经突的快速形成至关重要。同样，在层粘连蛋白包被的基质上生长的野生型PC12细胞也会对NGF和PMA的组合做出迁移并形成“快速神经突”的反应。这种快速迁移会被抗α1，β1整合素抗血清减弱，这表明存在层粘连蛋白 - 整合素相互作用；并且它会被α - 乳白蛋白抑制，这表明β1,4半乳糖基转移酶参与了该反应。快速神经突的形成不依赖于同时进行的蛋白质合成，但会被锂、细胞松弛素D和甲基硫代腺苷抑制，或者被用NGF预处理细胞所抑制。因此，在合适底物上生长的PC12细胞有能力快速迁移，从而在暴露于NGF和PMA的几分钟内形成类似神经元的突起。这种对多种因子组合的形态学反应可能为神经细胞形成连接提供了一种替代方式。或者，它可能反映了一种在发育过程中促进细胞迁移的机制。
