Park Sangwan, Suvarnpradip Naran, Kasiri Niusha, Yiu Glenn, Thomasy Sara M, Imai Denise M, Lloyd K C Kent, Leonard Brian C, Moshiri Ala
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California, United States.
Department of Ophthalmology & Vision Science, School of Medicine, University of California-Davis, Sacramento, California, United States.
Invest Ophthalmol Vis Sci. 2025 May 1;66(5):44. doi: 10.1167/iovs.66.5.44.
We sought to demonstrate the impact of Clic6 deficiency in the retina and RPE of C57BL/6N mice that are homozygous for the Crb1rd8 mutation.
Six Clic6-/- and six age-matched wild-type mice were used. Ophthalmic examination, ERG, and retinal optical coherence tomography were performed for clinical phenotyping. The mice were euthanized, and the eyes were processed for hematoxylin and eosin stain, immunohistochemistry, and transmission electron microscopy. Additionally, adult nonhuman primate and fetal human retinas were used for immunohistochemistry.
Both Clic6-/- and wild-type mice showed retinal lamination defects on optical coherence tomography and hematoxylin and eosin staining with a significantly greater number of lesions identified in Clic6-/- mice. No significant differences in ERG parameters were identified between genotypes. The expression of ezrin/radixin/moesin seemed to be flat and blunted at the apical RPE surface in Clic6-/- vs. wild-type mice. On transmission electron microscopy, Clic6-/- mice showed broadened and stout RPE microvilli with a significantly decreased apical microvilli height and significantly increased width of each RPE microvillus. Although the height of the RPE cells and basal infoldings and pigment granule density did not differ significantly, phagosome density was significantly greater in Clic6-/- mice. Both CLIC6 and ezrin/radixin/moesin were expressed in the RPE of adult nonhuman primate and fetal human tissues.
Clic6 deficiency induced aberrant RPE microvilli leading to a decreased intimacy between the RPE and photoreceptors and worsened the Crb1rd8 mutation phenotype that was inherent in C57BL/6N mice. CLIC6 may have a potential role in RPE dysfunction across species, including humans.
我们试图证明Clic6基因缺陷对纯合Crb1rd8突变的C57BL/6N小鼠视网膜和视网膜色素上皮（RPE）的影响。
使用6只Clic6基因敲除小鼠和6只年龄匹配的野生型小鼠。进行眼科检查、视网膜电图（ERG）和视网膜光学相干断层扫描以进行临床表型分析。对小鼠实施安乐死后，将眼睛进行苏木精-伊红染色、免疫组织化学和透射电子显微镜检查。此外，使用成年非人灵长类动物和胎儿人类视网膜进行免疫组织化学检查。
Clic6基因敲除小鼠和野生型小鼠在光学相干断层扫描和苏木精-伊红染色上均显示视网膜分层缺陷，且Clic6基因敲除小鼠中发现的病变数量明显更多。不同基因型之间未发现ERG参数有显著差异。与野生型小鼠相比，Clic6基因敲除小鼠中埃兹蛋白/根蛋白/膜突蛋白在RPE顶端表面的表达似乎扁平且减弱。在透射电子显微镜下，Clic6基因敲除小鼠显示RPE微绒毛变宽且粗壮，顶端微绒毛高度显著降低，每个RPE微绒毛宽度显著增加。尽管RPE细胞的高度、基底褶皱和色素颗粒密度没有显著差异，但Clic6基因敲除小鼠中的吞噬体密度显著更高。CLIC6和埃兹蛋白/根蛋白/膜突蛋白均在成年非人灵长类动物和胎儿人类组织的RPE中表达。
Clic6基因缺陷导致RPE微绒毛异常，导致RPE与光感受器之间的紧密程度降低，并使C57BL/6N小鼠固有的Crb1rd8突变表型恶化。CLIC6可能在包括人类在内的跨物种RPE功能障碍中具有潜在作用。
