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Abstract：
Usher syndrome (USH) is characterised by degenerative vision loss known as retinitis pigmentosa (RP), sensorineural hearing loss, and vestibular dysfunction. RP can cause degeneration and the loss of rod and cone photoreceptors, leading to structural and functional changes in the retina. Cep250 is a candidate gene for atypical Usher syndrome, and this study describes the development of a Cep250 KO mouse model to investigate its pathogenesis. OCT and ERG were applied in Cep250 and WT mice at P90 and P180 to access the general structure and function of the retina. After recording the ERG responses and OCT images at P90 and P180, the cone and rod photoreceptors were visualised using an immunofluorescent stain. TUNEL assays were applied to observe the apoptosis in Cep250 and WT mice retinas. The total RNA was extracted from the retinas and executed for RNA sequencing at P90. Compared with WT mice, the thickness of the ONL, IS/OS, and whole retina of Cep250 mice was significantly reduced. The a-wave and b-wave amplitude of Cep250 mice in scotopic and photopic ERG were lower, especially the a-wave. According to the immunostaining and TUNEL stain results, the photoreceptors in the Cep250 retinas were also reduced. An RNA-seq analysis showed that 149 genes were upregulated and another 149 genes were downregulated in Cep250 KO retinas compared with WT mice retinas. A KEGG enrichment analysis indicated that cGMP-PKG signalling pathways, MAPK signalling pathways, edn2-fgf2 axis pathways, and thyroid hormone synthesis were upregulated, whereas protein processing in the endoplasmic reticulum was downregulated in Cep250 KO eyes. Cep250 KO mice experience a late-stage retinal degeneration that manifests as the atypical USH phenotype. The dysregulation of the cGMP-PKG-MAPK pathways may contribute to the pathogenesis of cilia-related retinal degeneration.
摘要：
Usher综合征（USH）的特征是退行性视力丧失，称为视网膜色素变性（RP），感觉神经性听力损失,和前庭功能障碍。RP会导致杆状和锥形光感受器的退化和损失，导致视网膜的结构和功能变化。Cep250是非典型Usher综合征的候选基因,这项研究描述了Cep250KO小鼠模型的发展，以研究其发病机理。在P90和P180的Cep250和WT小鼠中应用OCT和ERG以获得视网膜的一般结构和功能。在P90和P180处记录ERG反应和OCT图像后,使用免疫荧光染色剂观察视锥和杆状光感受器。应用TUNEL法观察Cep250和WT小鼠视网膜的凋亡。从视网膜提取总RNA,并在P90进行RNA测序。与WT小鼠相比，ONL的厚度，IS/OS,Cep250小鼠的整个视网膜明显减少。Cep250小鼠在暗视和明视ERG中的a波和b波振幅较低,尤其是a波。根据免疫染色和TUNEL染色结果，Cep250视网膜中的光感受器也减少了。RNA-seq分析表明，与WT小鼠视网膜相比，Cep250KO视网膜中149个基因上调，另外149个基因下调。KEGG富集分析表明cGMP-PKG信号通路，MAPK信号通路,edn2-fgf2轴路径，甲状腺激素合成上调,而在Cep250KO眼中，内质网中的蛋白质加工被下调。Cep250KO小鼠经历晚期视网膜变性,表现为非典型USH表型。cGMP-PKG-MAPK通路的失调可能有助于纤毛相关视网膜变性的发病机理。
