Save Sight Institute, The University of Sydney, Sydney, NSW, 2000, Australia.
Save Sight Institute, The University of Sydney, Sydney, NSW, 2000, Australia.
Exp Eye Res. 2018 Oct;175:173-180. doi: 10.1016/j.exer.2018.06.016. Epub 2018 Jun 18.
Müller cells are the primary glia in the retina, playing a critical role in retinal homeostasis and retinal pathology. This study evaluated the canonical Wnt signalling pathway and its downstream effects on retinal degeneration in a transgenic mouse model of inducible Müller cell disruption. Increased expression of the LacZ reporter gene in the retina suggested Wnt signalling had been activated after induced Müller cell disruption. Activation was validated by observing nuclear translocation of β-Catenin. The mRNA expression of 80 Wnt related genes were assessed using real-time PCR. The Wnt signalling inhibitors Dkk1, Dkk3 and sFRP3 were significantly downregulated. Furthermore, the ubiquitin-mediated β-Catenin proteolysis genes β-TrCP and SHFM3, were also significantly downregulated. The downstream target genes of the Wnt signalling, including Fra1, CyclinD2 and C-Myc were upregulated. The changes of these genes at the protein level were validated by Western blot. Their distributions in the retina were evaluated by immunofluorescent staining. Our findings indicate that Müller cells are involved in retinal Wnt signalling. Activation of Wnt signalling and its downstream target genes may play important roles in photoreceptor degeneration and neovascularization occurring in the retina after induced disruption of Müller cells.
Müller 细胞是视网膜中的主要神经胶质细胞，在视网膜稳态和视网膜病变中起着关键作用。本研究评估了诱导型 Müller 细胞破坏的转基因小鼠模型中经典 Wnt 信号通路及其对视网膜变性的下游影响。在诱导 Müller 细胞破坏后，视网膜中 LacZ 报告基因的表达增加表明 Wnt 信号已被激活。通过观察 β-Catenin 的核易位来验证激活。使用实时 PCR 评估了 80 个与 Wnt 相关的基因的 mRNA 表达。Wnt 信号抑制剂 Dkk1、Dkk3 和 sFRP3 显著下调。此外，泛素介导的 β-Catenin 蛋白水解基因 β-TrCP 和 SHFM3 也显著下调。Wnt 信号的下游靶基因，包括 Fra1、CyclinD2 和 C-Myc，上调。通过 Western blot 验证了这些基因在蛋白质水平上的变化。通过免疫荧光染色评估了它们在视网膜中的分布。我们的研究结果表明，Müller 细胞参与了视网膜 Wnt 信号通路。Wnt 信号及其下游靶基因的激活可能在诱导 Müller 细胞破坏后发生的光感受器变性和新生血管形成中起重要作用。
