工频磁场对细胞神经酰胺代谢的影响及其在信号转导中的作用

In recent studies, we found that exposure to 50 Hz magnetic field (MF) could activate acid sphingomyelinase (ASM) and increase C24-ceramide level in cultured cells. It is suggested that 50 Hz MF exposure could affect the metabolism process of ceramide. Ceramide is a kind of lipid second messenger in cells. Ceramide and their metabolites usually exhibit crucial roles in signal transmembrane and intracellular signal transduction. However, the relationship between the biological effects of 50 Hz MF and ceramide or their metabolites is unclear. Based on our previous studies, the effect of 50 Hz MF exposure on ceramide metabolism spectra and metabolic pathways, the role of them in the process of receptor clustering and activation induced by 50Hz MF exposure will be investigated using confocal microscopy immunofluorescence technique, western blot and high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) in the present study. The research will benefit to elucidate the mechanism of signal transduction and molecular networks of biological effects of 50 Hz MF, and supply scientific data for preventing the harmful effects and applying the useful effects of 50 Hz MF.

我们在近期研究中发现，工频磁场辐照不仅能活化细胞内酸性鞘磷脂酶（ASM），还能诱导C24神经酰胺含量的增加，提示工频磁场可以影响细胞内神经酰胺的代谢过程。神经酰胺是细胞内重要的脂类第二信使，神经酰胺及其代谢产物可在细胞外信号跨膜传递和细胞内信号转导过程中发挥重要的作用。然而，神经酰胺及其代谢产物在工频磁场生物效应机制中的作用尚不清楚。本项目拟在前期研究成果的基础上，应用激光共聚焦免疫荧光技术、western blot技术以及高效液相色谱串联质谱分析等方法研究工频磁场辐照对细胞内神经酰胺代谢谱与代谢通路的影响，同时探索它们在工频磁场诱导细胞膜受体聚簇与活化中的作用，为工频磁场不良效应的防治以及正效应的应用提供科学依据。

在国家自然科学基金的资助下，本项目以FL细胞为模型，研究50Hz工频磁场暴露对细胞内神经酰胺代谢及相关信号通路的影响，获得了如下结果：.1、利用高效液相色谱串联四级杆质谱（high performance liquid chromatography tandem mass spectrometry，HPLC-MS/MS）检测技术，研究发现工频磁场暴露可以诱导细胞C16，C18和C24神经酰胺含量增高，但不影响神经酰胺的种类； .2、应用特异性抑制剂，发现工频磁场暴露可以通过酸性鞘磷脂酶水解和从头合成途径提高细胞内神经酰胺的含量；.3、工频磁场暴露可促进神经酰胺代谢产物鞘氨醇1磷酸的合成；.4、利用Western Blot技术和相关试剂盒，发现工频磁场暴露不影响蛋白酶Cathepsin D和蛋白磷酸酶PP2A的活性；.总之，通过该项目的研究，初步揭示了工频磁场暴露对细胞内神经酰胺代谢的影响及其通路，为极低频磁场生物效应的阐明提供基础。