WNK1磷酸化修饰在胆红素所致听觉中枢毒性中的作用及机制

听觉中枢受损引起的听觉障碍是胆红素脑病最主要的临床表型。既往研究证实胆红素能同时影响神经元多种离子通道及受体功能，提示其上游存在胆红素靶向的共同调节因子。磷酸化是细胞内最广泛的一种蛋白质翻译后修饰。前期实验我们利用磷酸化蛋白组学技术系统解析了胆红素对小鼠耳蜗核神经元蛋白磷酸化水平的调控，从中发现WNK1三个位点的磷酸化修饰水平在胆红素作用后显著下调。WNK1是一个丝苏氨酸蛋白激酶，在调控神经元离子通道等蛋白功能中具有重要作用。随后我们发现胆红素能促进WNK1向神经元轴突末端迁移并证实胆红素可以直接结合WNK1激酶的底物结合结构域。这些结果提示WNK1可能是胆红素所致听觉中枢神经元功能损伤的关键调控因子。本项研究拟在细胞水平和动物水平上，阐明胆红素是否通过靶向结合WNK1并调控其磷酸化修饰水平，从而影响听觉中枢神经元蛋白功能并诱发神经毒性，以期为胆红素听觉损伤的精准防治提供重要理论依据。

The hearing loss induced by the damage of auditory central system is the main clinical phenotype of bilirubin encephalopathy. Previous studies have confirmed that bilirubin can simultaneously affect the functions of many ion channels and receptors of neuron, suggesting that there is a common upstream regulatory factor which bilirubin targets directly. Phosphorylation is one of the most extensive post-translational modifications of proteins in cells. In our previous experiment, we systematically analyzed the regulation of bilirubin on protein phosphorylation level of cochlear nucleus neurons of mice by using phosphorylation proteomics technology, and found that the phosphorylation level of three sites of WNK1 was significantly down-regulated by bilirubin. WNK1 is a threonine protein kinase, which plays an important role in regulating protein functions such as neuronal ion channels. Later, we found that bilirubin can promote the migration of WNK1 to the axon end of neurons and confirmed that bilirubin can directly bind to the substrate binding domain of WNK1 kinase. These results suggest that WNK1 may be a key regulatory factor for bilirubin induced dysfunction of central auditory neurons. The purpose of this study is to clarify whether bilirubin can induce auditory central neurotoxicity by targeting WNK1 and regulating its phosphorylation level using both the cellular and animal model, so as to provide an important theoretical basis for the precise prevention and treatment of bilirubin induced hearing loss.