A novel and efficient murine model of Bietti crystalline dystrophy

Abstract

Bietti crystalline dystrophy (BCD) is an autosomal recessive inherited retinal disease, resulting in blindness in most patients. The etiology and development mechanism of it remain unclear. Given the defects in previous mouse models of BCD, we generated a new Cyp4v3−/− mouse model, using CRISPR/Cas9 technology, for investigating the pathogenesis of BCD. We estimated the ocular phenotypes by fundus imaging, optical coherence tomography (OCT) and full-field scotopic electroretinography, and investigated the histological features by Hematoxylin and Eosin staining, Oil Red O staining and immunofluorescence. This model effectively exhibited age-related progression that mimicked the human ocular phenotypes. Moreover, gas chromatography-mass spectrometry and RNA-seq analysis indicated that the defect of Cyp4v3 led to the abnormal lipid metabolism, inflammation activation and oxidative stress of retina. Notably, inflammation activation and oxidative stress could also promote the progression of BCD in light-induced retinal degeneration. In conclusion, our data provided evidence that we established a novel and more effective Cyp4v3 knockout preclinical mouse model for BCD, which served as a useful tool for evaluating the effect of drugs and gene therapy in vivo.

A Bietti Crystalline Dystrophy Mouse Model Shows Increased Sensitivity to Light-Induced Injury

“…In our model, there is a slight decrease in RPE cell number, and the retinal crystals are deposited beginning at 4–5 months of age. This is similar to the models described by Lockhart et al [ 7 ] and Jia [ 6 ], but later than that, described by Wang et al [ 5 ], while the mouse model described by Qu et al did not show significant changes without stress [ 4 ]. In addition, we did not detect any obvious abnormalities in the photoreceptors by immunofluorescence staining, which differs from the mouse model reported by Wang Y et al [ 5 ], although our model shows similar inflammatory changes.…”

“…This is similar to the models described by Lockhart et al [ 7 ] and Jia [ 6 ], but later than that, described by Wang et al [ 5 ], while the mouse model described by Qu et al did not show significant changes without stress [ 4 ]. In addition, we did not detect any obvious abnormalities in the photoreceptors by immunofluorescence staining, which differs from the mouse model reported by Wang Y et al [ 5 ], although our model shows similar inflammatory changes. Although the crystals in our model are phenotypically similar to the yellow spots seen in the Crb1 rd8 mouse retina [ 23 ], the mice used in this model did not contain the Crb1 rd8 mutation.…”

“…A number of BCD mouse models have been established using different gene editing strategies [ 4 , 5 , 6 , 7 ], each showing somewhat different phenotypes and responses to stress. Here we describe a Cyp4v3 KO mouse model with an inflammatory reaction in the retina, a reduced RPE cell number, and photoreceptors that are vulnerable to white light exposure.…”

“…It typically presents between the second and fourth decades of life with progressive night blindness, reduced vision, and eventually visual field constriction, often with legal blindness in the fifth or sixth decades of life. To date, no clinical treatment for this disease has been developed, although there have been some suggestive results with gene therapies in experimental mouse models [ 4 , 5 , 6 , 7 ].…”

“…CYP4V2 is a microsomal enzyme with ω-hydroxylase activity on both saturated and polyunsaturated medium and long-chain fatty acids [ 17 , 18 , 19 ] and is expressed in almost all body tissues, especially in the RPE and neural retina, in which alterations in lipid metabolism are proposed to be the major pathogenic mechanism of BCD. An induced pluripotent stem cell model [ 20 ] and three different murine knockout models have been generated [ 4 , 5 , 6 , 7 ]. All of these models provide valuable insight into the disease mechanisms.…”