# Upon Solving the Secrets for Lens Transdifferentiation

> **NIH NIH R01** · MIAMI UNIVERSITY OXFORD · 2024 · $385,526

## Abstract

Abstract
Urodele newts are the unrivaled champions of vertebrate tissue regeneration. A greater understanding of the
processes which enable their regenerative capabilities could inspire novel therapeutic approaches to combating
blinding ailments. After injury, the Spanish ribbed newt Pleurodeles waltl can regenerate its lens through the
transdifferentiation of iris pigment epithelium cells (IPECs) into lens progenitor cells. Interestingly, this
regenerative competence is restricted to IPECs within the dorsal compartment of the iris. Ventral IPECs are
nominally regeneration-incompetent, despite being morphologically indistinguishable from their dorsal
counterparts. Past efforts to identify molecular distinctions between dorsal and ventral IPECs have been unable
to pinpoint the precise determining factors for regeneration competence. These limitations were in part owing to
the large genomes of amphibians, which have precluded the robust delineation of gene structures. More recently,
our group has begun to address these limitations in Pleurodeles waltl, which now has an available reference
genome. Our preliminary observations suggest that the molecular foundations of IPEC regenerative competence
are determined by a highly conserved signaling axis relating to vertebrate eye development, including BMP and
Ephrin signaling cues. Upon surgical removal of the lens, we demonstrate that the newt iris undergoes distinct
shifts in the localization of BMP signaling effectors, serving as a molecular “switch” for regeneration competence.
Subsequently, the local environment of the dorsal iris is transformed into a pro-regenerative niche, whereas the
ventral iris is characterized by an acute injury-response program. Furthermore, we demonstrate that
pharmacologic perturbation of BMP or Ephrin signaling is sufficient to confer regenerative competence to ventral
IPECs. These results collectively lead us to hypothesize that newt lens regeneration is directed by a unique
gene regulatory paradigm that evolved downstream of the conserved BMP and Ephrin signaling axes. To
investigate this conjecture, we propose to comprehensively interrogate the role of these signaling axes in
directing dorsal and ventral IPEC injury responses. Gene regulatory mechanisms, including chromatin
accessibility profiling, will be performed on dorsal and ventral irises at landmark time points during lens
regeneration (Aim 1). Moreover, we will construct a spatiotemporal atlas of cell types associated with the
regenerative dorsal iris and non-regenerative ventral iris by leveraging cutting-edge techniques, including single-
nucleus RNA sequencing and spatial transcriptomics (Aim 2). Finally, we will systematically perturb the BMP
and Ephrin pathways during lens regeneration by using in vivo screens for druggable nodes within these
signaling cascades as well as transgenic newt lines (Aim 3). Collectively, these findings will greatly expand our
knowledge of the cellular and molecular determinants ...

## Key facts

- **NIH application ID:** 10879949
- **Project number:** 1R01EY035325-01A1
- **Recipient organization:** MIAMI UNIVERSITY OXFORD
- **Principal Investigator:** Katia Del Rio-Tsonis
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $385,526
- **Award type:** 1
- **Project period:** 2024-06-01 → 2029-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10879949

## Citation

> US National Institutes of Health, RePORTER application 10879949, Upon Solving the Secrets for Lens Transdifferentiation (1R01EY035325-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10879949. Licensed CC0.

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