Université de Nantes, CHU de Nantes, INSERM UMR 1089, Translational Gene Therapy for Genetic Diseases, Nantes, France.
Inserm UMR1280, Nantes, France.
FASEB J. 2021 Nov;35(11):e21934. doi: 10.1096/fj.202002525RRR.
Dysfunction of the ATPase-binding Cassette Transporter protein (ABCA4) can lead to early onset macular degeneration, in particular to Stargardt disease. To enable translational research into this form of blindness, we evaluated the effect of Cas9-induced disruptions of the ABCA4 gene to potentially generate new transgenic rat models of the disease. We show that deletion of the short exon preceding the second nucleotide-binding domain is sufficient to drastically knock down protein levels and results in accumulation of retinoid dimers similar to that associated with Stargardt disease. Overexpression of the retinol dehydrogenase enzymes RDH8 and RDH12 can to a limited extent offset the increase in the bisretinoid levels in the Abca4 - KO rats possibly by restricting the time window in which retinal can dimerize before being reduced to retinol. However, in vivo imaging shows that overexpression of RDH8 can induce retinal degeneration. This may be due to the depletion in the outer segment of the cofactor NADPH, needed for RDH function. The translational potential of RDH therapy as well as other Stargardt disease therapies can be tested using the Abca4 knockdown rat model.
ATP 结合盒转运蛋白（ABCA4）功能障碍可导致早发性黄斑变性，特别是斯塔加特病。为了能够将这种形式的失明转化为研究，我们评估了 Cas9 诱导的 ABCA4 基因破坏对潜在生成新的疾病转基因大鼠模型的影响。我们表明，删除第二个核苷酸结合域之前的短外显子足以明显降低蛋白水平，并导致视黄醛二聚体的积累，类似于与斯塔加特病相关的积累。视黄醇脱氢酶 RDH8 和 RDH12 的过表达在一定程度上可以抵消 Abca4-KO 大鼠中二聚体水平的增加，这可能是通过限制视网膜在还原为视黄醇之前二聚化的时间窗口来实现的。然而，体内成像显示 RDH8 的过表达可诱导视网膜变性。这可能是由于用于 RDH 功能的辅因子 NADPH 的外节耗尽所致。使用 Abca4 敲低大鼠模型可以测试 RDH 治疗以及其他斯塔加特病治疗的转化潜力。
