The objective of this study is to characterize the retinal degeneration (RD) phenotype of CXCR5/NRF2 double knockout (DKO) mice at the early adult age. CXCR5 KO mice and NRF2 KO mice were bred to create CXCR5/NRF2 DKO mice. The assessment of RD features included fundus and optical coherence tomography (OCT) imaging, periodic acid-Schiff (PAS), and immunofluorescence staining of retinal pigment epithelium (RPE)-choroid flatmounts. Stained samples were imaged with fluorescent microscopy, and Western blots were used to monitor protein expression changes. The staining of cleaved caspase-3 and PNA-lectin was performed to assess the presence of photoreceptor cell apoptosis. Quantification and statistical analyses were performed with Image J and Graphpad software. The young adult (2-6 months) DKO mice exhibited increased hypopigmented spots on fundus and sub-RPE abnormalities on OCT as compared to the CXCR5-KO mice, and C57BL6 WT controls. PAS-stained sections demonstrated aberrant RPE/sub-RPE depositions. The DKO mice had increased sub-RPE depositions of IgG and AMD-associated proteins (β-amyloid, Apolipoprotein-E, C5b-9, and αB-crystallin). The protein expression of AMD-associated proteins and microglia marker (TMEM119) were upregulated at the RPE/BM/choroid complex of DKO mice. The adult DKO mice underwent photoreceptor cell apoptosis compared to the single CXCR5 and NRF2 KO and the WT mice at an early adult age. Mechanistically increased expression of CXCL13 and N-cadherin was observed as a sign of epithelial-mesenchymal transition. The data suggest that the CXCR5/NRF2-DKO mice develop RD characteristics at an early age and may serve as a valuable animal model of RD.

中文翻译：

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CXCR5 / NRF2双敲除小鼠在成年早期发展为视网膜变性表型。

这项研究的目的是表征成年早期CXCR5 / NRF2双敲除（DKO）小鼠的视网膜变性（RD）表型。繁殖CXCR5 KO小鼠和NRF2 KO小鼠以创建CXCR5 / NRF2 DKO小鼠。RD的特征评估包括眼底和光学相干断层扫描（OCT）成像，高碘酸Schiff（PAS）以及视网膜色素上皮（RPE）-脉络膜平片的免疫荧光染色。用荧光显微镜对染色的样品成像，并使用蛋白质印迹法监测蛋白质表达的变化。对裂解的caspase-3和PNA-凝集素进行染色以评估感光细胞凋亡的存在。使用Image J和Graphpad软件进行定量和统计分析。与CXCR5-KO小鼠和C57BL6 WT对照相比，年轻的成年（2-6个月）DKO小鼠在OCT的眼底和亚RPE异常上表现出色素沉着斑点增加。PAS染色的切片显示异常的RPE / sub-RPE沉积。DKO小鼠的IgG和AMD相关蛋白（β-淀粉样蛋白，载脂蛋白-E，C5b-9和αB-晶状蛋白）的亚RPE沉积增加。在DKO小鼠的RPE / BM /脉络膜复合体中，AMD相关蛋白和小胶质细胞标记物（TMEM119）的蛋白表达上调。与单个CXCR5和NRF2 KO和野生型WT小鼠相比，成年DKO小鼠在成年早期经历了感光细胞凋亡。机械上增加的CXCL13和N-钙黏着蛋白的表达被观察到上皮-间质转化的迹象。