星形胶质细胞Connexin 43在锰神经毒性中的作用及其机制

Astrocytes are more vulnerable than neurons and they are the initial target in manganese-induced neurotoxicity. We had found the alternation of the number of cell junction in the manganese-treated astrocytes, which suggests the function of the cell junction channel change, followed by the change of the cell performance and the cell state. The astrocyte gap junctions are mainly composed of Connexin 43 (Cx43) which is also located at cytoplasm. There are gap junction channel/hemichannel function and non-channel function according to the location of the Cx43 . Up to now, there is no report on Cx43 of astrocyte in manganese-induced neurotoxicity yet. In the research, we will study the Cx43 (including gene transcription, protein translation, protein posttranslational modification: phosphorylation, protein subcellular localization and protein degradation), the Cx43 gap junction channel/hemichannel permeability , the cell performance (including calcium wave propagation, glutamate-glutamine metabolism, cell migration) and the cell state(cell vitality, cell apoptosis) in response to the manganese-induced toxicity ; then we will reveal the relationship between the Cx43 channel/hemichannel permeability and performance of astrocyte, the relationship between the Cx43 channel/hemichannel permeability and the state(cell vitality, cell apoptosis) of the cells in purified astrocyte culture, the relationship between the Cx43 channel/hemichannel permeability and the state of the neurons in the astrocyte-neuron co-culture . Further more, we would intervene the expression of Cx43 to explore the molecular mechanism of the Cx43 non-channel function in astrocytes treated with manganese. The result of the study may shed new light on the mechanism underlying manganese toxicity related neurological disorders and provide theoretical foundation for effective drug development.

星形胶质细胞(astrocyte,AS)损伤是锰神经毒性发生、发展的重要原因。我们前期实验发现：锰处理的AS细胞连接数量改变。这种改变暗示细胞通道功能改变，进而影响细胞性能、状态。缝隙连接蛋白Connexin 43(Cx43)构成AS最主要的细胞连接，它也分布于胞浆，具有通道(含半通道)功能及非通道功能。国内外锰神经毒性研究尚未见报道涉及AS 的Cx43。本研究拟采用锰干预处理细胞模型，研究AS Cx43(含基因转录、翻译、蛋白定位及降解等环节)及其通道通透性、细胞性能(钙波传播、谷氨酸代谢、细胞迁移等)及细胞状态(细胞活力、细胞凋亡)对锰毒性的响应；研究锰毒性下Cx43通道通透性对细胞性能、细胞状态(含AS及共培养体系中神经元)影响；通过干预Cx43表达进一步验证锰处理AS中 Cx43的功能并探索其非通道功能的分子机制。本研究有助于揭示锰神经毒性损伤机制，为寻找有效治疗药物提供理论依据。