# Dicer is essential for proper maturation, composition, and function in the postnatal retina

## TL;DR

This study shows that Dicer, a key component of microRNA processing, is crucial for the proper development and function of retinal cells in mice after birth.

## Contribution

The study reveals that Dicer in postnatal retinal progenitor cells is essential for cell maturation and retinal function.

## Key findings

- Dicer loss in retinal progenitor cells leads to impaired rod function and fewer rod bipolar cells.
- Dicer depletion causes an overproduction of amacrine cells and a reduced Müller glia population.
- An immature progenitor cell population persists into adulthood when Dicer is absent.

## Abstract

The impact of Dicer/miRNAs during postnatal retinogenesis is unknown. This study aimed to deplete Dicer in postnatal retinal progenitor/precursor cells (RPCs/PCs) and to evaluate the structure and function of the adult Dicer-cKO retina using optical coherence tomography (OCT), electroretinography (ERG), and histology. We found impaired rod function, a significantly reduced number of rod bipolar cells and their associated functions, a decreased Müller glia population, and an increased population of HuC/D + Pax6/+ amacrine cells in the adult Dicer-cKO retina. Transcriptional analyses conducted in one-week-old mice showed early alterations in mRNA and miRNA levels. Single-cell RNA sequencing and initial histological analysis in young mice revealed a delay in differentiation/incomplete maturation, as indicated by an enlarged progenitor/precursor population at young ages that persists into adulthood. This suggests that Dicer/miRNAs in late RPC/PCs are essential for the proper formation and maturation of late RPC progenies and may also play a role in regulating cell state.

•Postnatal progenitor Dicer/miRNAs are essential for retinal cell maturation•Postnatal Dicer loss impacts rod, bipolar cell, and Müller glia development•Postnatal Dicer loss in retinal progenitors leads to amacrine cell overproduction•Dicer loss causes an immature cell population to persist until adulthood

Postnatal progenitor Dicer/miRNAs are essential for retinal cell maturation

Postnatal Dicer loss impacts rod, bipolar cell, and Müller glia development

Postnatal Dicer loss in retinal progenitors leads to amacrine cell overproduction

Dicer loss causes an immature cell population to persist until adulthood

Molecular biology; Neuroscience; Cell biology; Developmental biology