# Single-Cell Transcriptomics on PRPF31-Mutated Retinal Organoids Reveal Early Müller Glial Activation and Progressive Photoreceptor Degeneration

## TL;DR

This study uses retinal organoids to show how PRPF31 mutations cause early glial activation and later photoreceptor loss in a form of retinitis pigmentosa.

## Contribution

The study introduces a novel in vitro model of RP11 using single-cell transcriptomics to capture early and late disease dynamics.

## Key findings

- PRPF31 mutations trigger early activation of Müller glia and distress in retinal ganglion cells.
- Progressive photoreceptor degeneration is linked to dysregulated pathways in phototransduction and oxidative stress.
- The study identifies compensatory responses in non-photoreceptor retinal cells due to PRPF31 mutations.

## Abstract

Background: Retinitis pigmentosa (RP) encompasses a group of inherited retinal disorders characterized by progressive degeneration of rod and cone photoreceptors, leading to vision loss. Among RP subtypes, RP11 is linked to mutations in PRPF31, a key spliceosome component, resulting in retinal cell dysfunction. Although PRPF31 is ubiquitously expressed, its mutations predominantly impact retinal cells, leading to the progressive loss of photoreceptors. Despite significant progress, studies have focused on photoreceptor and retinal pigment epithelium dysfunction in late disease stages, leaving early molecular events and the involvement of other retinal cell types unresolved. Moreover, comprehensive single-cell analyses capturing dynamic transcriptional changes across all retinal populations at early and late differentiation stages are still lacking. Methods: Using patient-derived retinal organoids (ROs), this study investigates the impact of PRPF31-RP11 mutation through a series of morphological, functional, molecular, and transcriptomics analyses. Results:. Single-cell RNA sequencing revealed dynamic gene expression related to early Müller glia activation, retinal ganglion cell distress, and progressive photoreceptor degeneration. Findings identify dysregulated molecular pathways associated with phototransduction, oxidative stress, and inflammation. Conclusions: Our results support a specific RO model of RP11 in which PRPF31 mutation recapitulate in vitro key features of RP, while simultaneously eliciting compensatory or modulatory responses in other retinal cell types.