Antisense oligonucleotide allele-specific targeting of EFEMP1 in a patient-derived model of Doyne honeycomb retinal dystrophy.

Doyne honeycomb retinal dystrophy is an incurable juvenile macular dystrophy that leads to visual impairment by early to mid-adulthood. It is an autosomal dominant disorder caused by a c.1033C>T, p.(Arg345Trp) variant in EFEMP1, and is characterized by the early onset of extracellular deposition of drusen between the retinal pigment epithelium and underlying Bruch's membrane. In this study, we developed an antisense oligonucleotide approach to target EFEMP1. We reprogrammed patient-derived renal epithelial cells to induced pluripotent stem cells, followed by directed differentiation to retinal pigment epithelium and compared the phenotype to gene-corrected and EFEMP1 knockout patient-derived retinal pigment epithelium. In the patient-derived disease model, remodeling of the extracellular matrix (ECM) occurred with progressive accumulation of the drusen-associated proteins apolipoprotein E and collagen IV, in addition to the intracellular accumulation and extracellular deposition of lipids. We developed an allele-specific antisense oligonucleotide which specifically and effectively promoted the clearance of the EFEMP1 c.1033C>T transcript in the patient-derived disease model following assisted or gymnotic delivery. Gymnotic delivery rescued remodeling of the ECM, reduced intracellular accumulation of lipids, and cleared extracellular deposits, even after the onset of the disease phenotype, suggesting that this could be a practical and effective therapeutic approach.