PTEN调控AMPA受体GluR2亚单位促进放射性脊髓损伤神经元病理进程的机制研究

It has been well documented that glutamate excitotoxicity mediated-calcium overload is implicated in the neuron death. In our preliminary data, we found that a large number of neurons died in the early stage of radiation-induced spinal cord injury (RI-SCI). Hydroxymethyl amino-oxazole propionic acid (AMPA) receptor, which is one of key glutamate receptors, is induced the neuronal calcium overload mainly dependent on GluR2 subunit deletion, while its function is particularly influenced by phosphorylation. It has been widely investigated that Proteins encoded by tumor suppressor gene PTEN can directly regulate receptors function by forming PTEN-receptor complex. Based on these results, we propose here to determine the changes of morphology and function in neurons influenced by PTEN, and its relationship with GluR2 subunit. The results from this proposal will provide better insight in the mechanisms underlying the moduation effects between PTEN and AMPA-GluR2 subunit in neurons during RI-SCI, which could serve as a basis for further research, treatment and drug development.

我们在前期研究中发现放射性脊髓损伤早期即有神经元大量死亡，而谷氨酸兴奋性中毒导致的钙超载是神经元死亡的重要机制。氨基羟甲基恶唑丙酸（AMPA）受体是重要的谷氨酸受体，AMPA受体介导的神经元钙超载主要依赖于GluR2亚单位的缺失，而磷酸化作用对AMPA受体功能的影响尤为重要。肿瘤抑制基因PTEN编码的蛋白可与受体形成复合物，直接调节受体功能。本项目拟通过离体实验观察PTEN对放射损伤的神经元形态和功能变化的影响及其与GluR2的相互关系，为放射性脊髓损伤的进一步研究、治疗及药物研发提供新思路和新举措。

针对人和大鼠PTEN基因的同源序列设计shRNA序列，并构建在慢病毒干扰表达载体上，该载体含有ZsGreen绿色荧光标记基因，能通过荧光，直观的观察病毒的感染情况；同时，该载体带有Puromycin抗性基因，可用于构建稳转细胞株。本项目按4年研究周期设计，基金委只批准了1年期的面上项目，尽管经费存在极大困难，我们实际还是按申请书的4年期项目进行课题研究。在本项目的经费资助下，我们已在国际期刊J Transl Med、Brain Res、Int J Mol Med杂志发表SCI论文3篇，尚有数篇论文正在审稿，举办小型研讨会2次。