# AAV-mediated Müller glia reprogramming to early-stage retinal progenitor cells

> **NIH NIH F31** · JOHNS HOPKINS UNIVERSITY · 2024 · $48,190

## Abstract

Early-stage and late-stage retinal progenitor cells (RPCs) selectively generate retinal neurons in
discrete temporal windows over the course of retinal development. Müller glia (MG), and late-stage RPCs have
similar gene expression profiles and express many shared transcription factors (TFs) that repress proliferative
and neurogenic competence. Upon retinal injury, many of these TFs are downregulated in MG, while TFs that
drive reactive gliosis are upregulated. This process is necessary to activate neurogenic competence in fish and
amphibians. However, MG in mammals lack neurogenic competence, and TFs that maintain quiescence are
rapidly re-expressed following injury. We have identified key regulators of proliferative and neurogenic
competence in both RPCs and MG through multiomic analyses. I am now exploring the possibility that a single
AAV-based reagent can be used to reprogram MG to early-stage RPC-like cells that generate early-born
retinal cell types, including cone photoreceptors, in situ. I hypothesize that MG can be reprogrammed to gain
proliferative and neurogenic competence in mammals by disrupting the function of TFs that promote late-stage
RPC identity and are also expressed in adult MG. Furthermore, I anticipate that overexpression of TFs that
promote early-stage RPC identity in MG-derived progenitors may promote generation of early-born retinal cell
types (Fig 1B). Finally, by combining these overexpression and loss of function approaches with
overexpression of TFs that promote photoreceptor specification, I expect to be able to generate substantial
numbers of early-born cone photoreceptors. I propose two aims to address this hypothesis. Aim I: Alter retinal
development trajectory and reprogram adult MG using overexpression of full-length and dominant-negative
constructs of candidate TFs. Multiplexed single-cell (sc)RNA-seq analysis will be used to identify constructs
that promote proliferative and neurogenic competence in electroporated late-stage RPCs and transduced adult
MG. Immunohistochemistry will be used to validate findings from the scRNA-seq data. This aim will allow for
the functional characterization of TFs that regulate the transition between early and late stages of
developmental competence in RPCs, as well as the transition of MG from a quiescent to a neurogenic state.
This aim will also identify constructs that promote the production of early-born cell types, including cone
photoreceptors, in neonatal retinal explants and mature MG. Aim II: Overexpression of Prdm1 in
reprogrammed adult MG to drive cone photoreceptor formation. Prdm1 is selectively and strongly expressed in
photoreceptor precursors and stimulates photoreceptor differentiation. Overexpression of Prdm1 may induce
reprogrammed MG to produce early-stage RPC-like cells that are neurogenic and specifically generate mature
cone photoreceptors. This project has significant potential to contribute to the development of novel gene
therapies for photoreceptor dy...

## Key facts

- **NIH application ID:** 10886487
- **Project number:** 5F31EY034774-02
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Nicole Pannullo
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $48,190
- **Award type:** 5
- **Project period:** 2023-07-01 → 2025-06-20

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10886487

## Citation

> US National Institutes of Health, RePORTER application 10886487, AAV-mediated Müller glia reprogramming to early-stage retinal progenitor cells (5F31EY034774-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10886487. Licensed CC0.

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