The RNA content of extracellular vesicles from gene-edited PRPF31 (+/-) hiPSC-RPE show potential as biomarkers of retinal degeneration.

Retinitis pigmentosa (RP) is the most common inherited retinal degeneration (IRD), causing vision loss via the dysfunction and death of photoreceptors and retinal pigment epithelium (RPE). Mutations in the PRPF31 gene are associated with autosomal dominant RP, impairing RPE function. While adeno-associated virus (AAV)-mediated gene therapy shows promise for treating IRDs, the slow progression of these diseases often makes timely measurement of clinical efficacy challenging. Extracellular vesicles (EVs) are lipid enclosed vesicles secreted by cells, and their RNA contents are being explored as circulating biomarkers for other diseases. We hypothesize that EV RNAs could serve as biomarkers of the health status of the neural retina and RPE. To test this, we used PRPF31 (+/+) and PRPF31 (+/-) human induced pluripotent stem cell (hiPSC)-derived RPE (hi-RPE) to investigate the RNAs contained in RPE-derived EVs and how they change in disease. We also compared the RNA contents of RPE-EVs with the RNAs of the hi-RPE cells themselves. We found that EVs from mutant PRPF31 hi-RPE cells have distinct RNA profiles compared to those from control cells, suggesting that EV RNA contents change during disease. Additionally, we identified 18 miRNAs and 865 poly(A) RNAs enriched in EVs from PRPF31 (+/-) hi-RPE, which could serve as biomarkers for RPE degeneration.