Gu Xiao-He, Li Heng, Zhang Lin, He Tao, Chai Xiang, Wei He, Gao Dian-Shuai
Department of Anatomy and Neurobiology, Xuzhou Medical University, Xuzhou, Jiangsu Province, China.
Department of Neurosurgery, First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China.
Neural Regen Res. 2020 Feb;15(2):270-276. doi: 10.4103/1673-5374.265561.
Glial cell line-derived neurotrophic factor (GDNF) plays a critical role in neuronal survival and function. GDNF has two major splice variants in the brain, α-pro-GDNF and β-pro-GDNF, and both isoforms have strong neuroprotective effects on dopamine neurons. However, the expression of the GDNF splice variants in dopaminergic neurons in the brain remains unclear. Therefore, in this study, we investigated the mRNA and protein expression of α- and β-pro-GDNF in the mouse brain by real-time quantitative polymerase chain reaction, using splice variant-specific primers, and western blot analysis. At the mRNA level, β-pro-GDNF expression was significantly greater than that of α-pro-GDNF in the mouse brain. In contrast, at the protein level, α-pro-GDNF expression was markedly greater than that of β-pro-GDNF. To clarify the mechanism underlying this inverse relationship in mRNA and protein expression levels of the GDNF splice variants, we analyzed the expression of sorting protein-related receptor with A-type repeats (SorLA) by real-time quantitative polymerase chain reaction. At the mRNA level, SorLA was positively associated with β-pro-GDNF expression, but not with α-pro-GDNF expression. This suggests that the differential expression of α- and β-pro-GDNF in the mouse brain is related to SorLA expression. As a sorting protein, SorLA could contribute to the inverse relationship among the mRNA and protein levels of the GDNF isoforms. This study was approved by the Animal Ethics Committee of Xuzhou Medical University, China on July 14, 2016.
胶质细胞系源性神经营养因子（GDNF）在神经元存活和功能中起关键作用。GDNF在大脑中有两种主要的剪接变体，α-pro-GDNF和β-pro-GDNF，这两种异构体对多巴胺能神经元都有很强的神经保护作用。然而，GDNF剪接变体在大脑多巴胺能神经元中的表达仍不清楚。因此，在本研究中，我们使用剪接变体特异性引物，通过实时定量聚合酶链反应和蛋白质印迹分析，研究了小鼠脑中α-和β-pro-GDNF的mRNA和蛋白质表达。在mRNA水平上，β-pro-GDNF在小鼠脑中的表达显著高于α-pro-GDNF。相反，在蛋白质水平上，α-pro-GDNF的表达明显高于β-pro-GDNF。为了阐明GDNF剪接变体mRNA和蛋白质表达水平这种反向关系的潜在机制，我们通过实时定量聚合酶链反应分析了具有A型重复序列的分选蛋白相关受体（SorLA）的表达。在mRNA水平上，SorLA与β-pro-GDNF的表达呈正相关，但与α-pro-GDNF的表达无关。这表明小鼠脑中α-和β-pro-GDNF的差异表达与SorLA的表达有关。作为一种分选蛋白，SorLA可能导致GDNF异构体mRNA和蛋白质水平之间的反向关系。本研究于2016年7月14日获得中国徐州医科大学动物伦理委员会批准。
