Increasing cellular level of phosphatidic acid enhances FGF-1 production in long term-cultured rat astrocytes
Increasing cellular level of phosphatidic acid enhances FGF-1 production in long term-cultured rat astrocytes
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DOI：
10.1016/j.brainres.2014.03.035
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发表时间：
2014-05
期刊：
影响因子：
2.9
通讯作者：
Y. Nagayasu;Shin-ya Morita;H. Hayashi;Y. Miura;Kazuki Yokoyama;M. Michikawa;J. Ito
中科院分区：
文献类型：
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作者：
Y. Nagayasu;Shin-ya Morita;H. Hayashi;Y. Miura;Kazuki Yokoyama;M. Michikawa;J. Ito
我们在之前的一项研究中发现，长期培养一个月的大鼠星形胶质细胞（W/M细胞）中成纤维细胞生长因子1（FGF-1）的mRNA表达和释放量均高于培养一周的细胞（W/W细胞）。然而，FGF-1 不会增强 W/M 细胞中 Akt、MEK 和 ERK 的磷酸化，而在 W/W 细胞中却会增强。在这项工作中，我们研究了导致培养中 W/W 和 W/M 细胞之间这些差异的机制。众所周知，长期培养会产生氧化应激，我们将 W/M 细胞与 W/W 细胞相比所经历的应激进行了表征。 W/M 细胞中超氧化物歧化酶 1 (SOD1) 和线粒体 Bax 的水平高于 W/W 细胞。 W/M 细胞恢复了响应 FGF-1 的能力，从而在抗氧化剂存在的情况下增强 Akt、MEK 和 ERK 的磷酸化。过氧化氢（H2O2）诱导的氧化应激对W/W细胞中FGF-1的mRNA表达没有影响，尽管H2O2增强了W/W细胞中FGF-1的释放而不诱导细胞凋亡。研究了细胞密度对 FGF-1 mRNA 表达和细胞对 FGF-1 反应的影响，因为在 W/M 细胞中观察到细胞密度增加。细胞密度的增加增强了 W/W 细胞中 FGF-1 mRNA 的表达，但不抑制对 FGF-1 的反应。细胞密度的降低降低了 W/M 细胞中 FGF-1 mRNA 的表达，但没有恢复对 FGF-1 增强 Akt、MEK 和 ERK 磷酸化的反应。这些发现表明，氧化应激会减弱对 FGF-1 的敏感性，并且较高的细胞密度可能会增强 W/M 细胞中的 FGF-1 表达。此外，我们发现H2O2处理的W/W和W/M细胞中磷脂酸（PA）的细胞水平增加，而抗氧化剂处理则降低，并且PA增强W/W细胞中FGF-1的mRNA表达。这些发现表明，PA 产量的增加可能会增强 FGF-1 的表达，以保护星形胶质细胞免受长期培养引起的氧化应激。
We found in a previous study that both mRNA expression and release of fibroblast growth factor 1 (FGF-1) are greater in rat astrocytes that are long term-cultured for one month (W/M cells) than in the cells cultured for one week (W/W cells). However, FGF-1 does not enhance phosphorylation of Akt, MEK, and ERK in W/M cells, while it does in W/W cells. In this work we studied the mechanism to cause these differences between W/W and W/M cells in culture. As it is known that long term culture generates oxidative stress, we characterized the stresses which W/M cells undergo in comparison with W/W cells. The levels of superoxide dismutase 1 (SOD1) and mitochondrial Bax were higher in W/M cells than in W/W cells. W/M cells recovered their ability to respond to FGF-1 to enhance phosphorylation of Akt, MEK, and ERK in the presence of antioxidants. Oxidative stress induced by hydrogen peroxide (H2O2) had no effect on mRNA expression of FGF-1 in W/W cells, although H2O2enhances release of FGF-1 from W/W cells without inducing apoptosis. The influence of cell density was studied on mRNA expression of FGF-1 and cellular response to FGF-1, as an increasing cell density is observed in W/M cells. The increasing cell density enhanced mRNA expression of FGF-1 in W/W cells without suppression of responses to FGF-1. The decrease in cell density lowered the FGF-1 mRNA expression in W/M cells without recovery of the response to FGF-1 to enhance phosphorylation of Akt, MEK, and ERK. These findings suggest that oxidative stress attenuate sensitivity to FGF-1 and higher cell density may enhance FGF-1 expression in W/M cells. In addition, we found that the cellular level of phosphatidic acid (PA) increased in H2O2-treated W/W and W/M cells and decreased by the treatment with antioxidants, and that PA enhances the mRNA expression of FGF-1 in the W/W cells. These findings suggest that the increasing PA production may enhance FGF-1 expression to protect astrocytes against oxidative stress induced by long-term culture.