Trial of regeneration of retinal neuronal cells by myoseverin

肌丝蛋白是一种微管结合分子，可诱导C2C12肌管去分化为单个肌细胞。1)大鼠嗜铬细胞瘤PC12细胞经神经生长因子(NGF)诱导分化为神经细胞。加入肌丝蛋白对NGF处理的PC12细胞的去分化无促进作用。然而，当肌丝蛋白与NGF同时作用于PC12细胞时，约有15%的细胞轴突伸展受到抑制。2)RalGDS的诱导可抑制NGF诱导的PC12细胞分化。我们发现肌丝蛋白可诱导PC12细胞RalGDS的mRNA表达。因此，RalGDS可能在抑制神经生长因子诱导的分化中起重要作用。3)克隆了PC12细胞中肌丝蛋白诱导的额外基因，并克隆了核糖体PO基因、cofilin和Gadd45β。我们建立了稳定表达这些基因的PC12细胞株，并检测了它们对NGF的反应。4)体外培养孕12天大鼠胚胎视网膜色素上皮细胞。碱性成纤维细胞生长因子诱导细胞增殖，抑制细胞色素沉着，上调神经前体细胞分子标志物CHX10和Nestin的表达。5)培养7d后，虽然bFGF诱导了MULER细胞的分子标志物--胶质纤维酸性蛋白(GFAP)的表达，但MYSERIN的加入抑制了这种诱导，因此，MYSERIN在诱导RPE向成熟神经细胞分化的初期有协同作用，但其毒性可能抑制了其向成熟神经细胞的进一步分化。

Myoseverin is a microtubule-binding molecule that induces the dedifferentiation of C2C12 myotubes to individual muscle cells. Here we present the trial of the neural cell regeneration by myoseverin.1) Rat pheochromocytoma PC12 cells differentiate to nerve cells by nerve growth factor (NGF). Addition of myoseverin did not promote of dedifferentiation of NGF-treated PC12 cells. However, when myoseverin was added simultaneously with NGF to PC12 cells, extension of axons was inhibited in about 15% cells. But they did not proliferate and finally exhibited apoptic cell death.2) The induction of RalGDS has been known to inhibit the NGF-induced differentiation of PC12 cells. We found that myoseverin induced the mRNA of RalGDS in PC12 cells. Thus, RalGDS might play an important role in inhibiting NGF-induced differentiation.3) We tried to clone the additional myoseverin-induced genes in PC12 cells and ribosomal PO gene, cofilin and GADD45β were cloned. We established the individual PC12 cell lines that stably expressed those genes and examined their response to NGF. Those cell lines, however, differentiated upon NGF stimulation as parental PC12 cells.4) Retinal pigment epithelial (RPE) cells of rat embryo at day 12 of gestation were cultured in vitro. Basic fibroblast growth factor (bFGF) induced cell proliferation, suppressed their pigmentation, and increased the expression of CHX10 and nestin that were molecular markers of neural progenitors. Myoseverin enhanced these bFGF effects up to about 30%.5) Although bFGF induced the expression of glial fibrillary acidic protein (GFAP) that was a molecular marker of Muller glial cells after 7 days culture, addition of myoseverin inhibited the induction.Thus, while myoseverin has a cooperative effect on the transdifferentiation of RPE induced by bFGF during an initial stage, probably its toxicity inhibited their further differentiation to mature neural cells.