Analyses of neuronal apoptosis inhibitory proteins and high-density culture sensitive genes

我们鉴定了皮质神经元无血清培养分泌的凋亡抑制因子（AIFs）。在低密度培养的大鼠胚胎皮层细胞的死亡被抑制的条件培养基（CM）从高密度培养。我们纯化了这些AIE-20和AIF-22，并揭示了这两种因子通过蛋白激酶C机制抑制细胞凋亡。这种抑制活性是特定的大鼠皮层神经元，但不为背根神经节神经元或PC 12嗜铬细胞瘤细胞。此外，各种已知的（神经）营养因子在无血清条件下的本培养系统中没有效果。这些发现表明AIF-20和AIF-22都是通过蛋白激酶C机制作用于皮层神经元的新型自分泌或旁分泌型营养因子。另一方面，我们克隆了高密度培养特异性基因HDS 1和HDS 2。在高密度培养物中加入HDS 1反义寡核苷酸抑制了细胞的存活活性，而在低密度培养物中加入表达HDS 1的疱疹病毒载体则增强了细胞的存活活性。这些数据表明，HDS 1参与密度依赖性存活作用。

We identified the apoptosis-inhibitory factors (AIFs) secreted from serum-free culture of cortical neurons. The cell death in low-density culture of the cortex of rat embryos was suppressed by the addition of conditioned medium (CM) from high-density cultures. We purified such AlEs, AIE-20 and AIF-22 and revealed that these two factors were active in suppressing the apoptosis through protein kinase C mechanisms. Such apoptosis-inhibitory activity was specific for rat cortical neurons, but not for dorsal root ganglion neurons or PC12 pheochromocytoma cells. Furthermore, various known (neuro) trophic factors had no effects in the present culture system under the serum-free condition. These findings suggest that AIF-20 and AIF-22 are both novel autocrine or paracrine type of trophic factors acting through protein kinase C mechanisms for cortical neurons. On the other hand, we cloned high-density culture specific genes, HDSI and HDS2. The survival activity was suppressed by addtion of HDS1 antisense oligonucleotides to the high-density culture and was enhanced by addition of a herpesvirus vector for expressing HDS1 to the low-density culture. These data suggest that the HDS1 is involved in the density-dependent survival action.