Abstract
Purpose :
Mutations in the gene encoding the ciliary protein lebercilin result in defects in intraflagellar trafficking (IFT) and cause a severe, childhood onset retinal degeneration known as Leber’s congenital amaurosis 5 (LCA5). The human condition is modeled in an engineered mouse model (Boldt et al, JCI 121:2169 (2011)). We tested the hypothesis that delivery of the wildtype human LCA5 cDNA would ameliorate the phenotype in this model.
Methods :
The wildtype human LCA5 cDNA was delivered unilaterally to the eyes of neonatal Lca5-/- mice using AAV9 or AAV7m8 (1ul of 9.3E12-1.47E13 vg/ml virus per eye). AAV9 was delivered subretinally and AAV7m8 was delivered intravitreally. Contralateral eyes were untreated and used as internal controls. Untreated but punctured littermates were used as additional controls. Retinal and visual function was assessed by pupillometry (1000 and 3000 scot lux 5 ms stimuli) and by a water maze test (luminance of LED light source identifying the escape platform was 6E4 and 3E2 scot cd m-2 for training and testing respectively). Structural effects were evaluated by retinal histology.
Results :
In 46 out of 49 treated mice, pupillometry revealed an increased pupil response in the treated eye as compared to the control one. In the water maze 40 out of 44 treated mice but only 2 out of 22 controls passed the test (p<0.001 by Fisher exact test). Histological analysis confirmed a greater number of retained photoreceptor cells in treated retinas as compared to controls.
Conclusions :
Gene augmentation therapy with rAAV vectors rescues retinal structure and function in a mouse model of LCA5.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.