Faculty Collaboration Database

Gene Augmentation and Readthrough Rescue Channelopathy in an iPSC-RPE Model of Congenital Blindness. Am J Hum Genet 2019 Feb 07;104(2):310-318

Date

01/29/2019

Pubmed ID

30686507

Pubmed Central ID

PMC6369573

DOI

10.1016/j.ajhg.2018.12.019

Scopus ID

2-s2.0-85060979568 (requires institutional sign-in at Scopus site)   20 Citations

Abstract

Pathogenic variants of the KCNJ13 gene are known to cause Leber congenital amaurosis (LCA16), an inherited pediatric blindness. KCNJ13 encodes the Kir7.1 subunit that acts as a tetrameric, inwardly rectifying potassium ion channel in the retinal pigment epithelium (RPE) to maintain ionic homeostasis and allow photoreceptors to encode visual information. We sought to determine whether genetic approaches might be effective in treating blindness arising from pathogenic variants in KCNJ13. We derived human induced pluripotent stem cell (hiPSC)-RPE cells from an individual carrying a homozygous c.158G>A (p.Trp53^∗) pathogenic variant of KCNJ13. We performed biochemical and electrophysiology assays to confirm Kir7.1 function. We tested both small-molecule readthrough drug and gene-therapy approaches for this "disease-in-a-dish" approach. We found that the LCA16 hiPSC-RPE cells had normal morphology but did not express a functional Kir7.1 channel and were unable to demonstrate normal physiology. After readthrough drug treatment, the LCA16 hiPSC cells were hyperpolarized by 30 mV, and the Kir7.1 current was restored. Similarly, we rescued Kir7.1 channel function after lentiviral gene delivery to the hiPSC-RPE cells. In both approaches, Kir7.1 was expressed normally, and there was restoration of membrane potential and the Kir7.1 current. Loss-of-function variants of Kir7.1 are one cause of LCA. Using either readthrough therapy or gene augmentation, we rescued Kir7.1 channel function in iPSC-RPE cells derived from an affected individual. This supports the development of precision-medicine approaches for the treatment of clinical LCA16.

Author List

Shahi PK, Hermans D, Sinha D, Brar S, Moulton H, Stulo S, Borys KD, Capowski E, Pillers DM, Gamm DM, Pattnaik BR

Author

Simran Brar OD Assistant Professor in the Ophthalmology and Visual Sciences department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Base Sequence
Blindness
Channelopathies
Child
Genetic Therapy
Humans
Induced Pluripotent Stem Cells
Leber Congenital Amaurosis
Models, Biological
Potassium Channels, Inwardly Rectifying
Retinal Pigment Epithelium