# The PERK inhibitor GSK2606414 evokes developmental defects in zebrafish consistent with Wolcott-Rallison syndrome phenotypes

## TL;DR

This study shows that a PERK inhibitor causes developmental defects in zebrafish similar to those seen in Wolcott-Rallison Syndrome, suggesting zebrafish could be a useful model for studying this condition.

## Contribution

Demonstrates that zebrafish can model Wolcott-Rallison Syndrome phenotypes through PERK inhibition, offering a scalable platform for drug screening.

## Key findings

- GSK2606414 induces WRS-like skeletal and neuromuscular defects in zebrafish.
- The drug reduces β-cell mass and glucose uptake, mimicking diabetic-like features.
- Zebrafish PERK shares critical residues with human PERK, supporting functional similarity.

## Abstract

Protein kinase RNA-like endoplasmic reticulum kinase (PERK) is an endoplasmic reticulum stress kinase whose loss of function disturbs human development, leading to skeletal dysplasia and permanent neonatal diabetes, as in the Wolcott-Rallison Syndrome (WRS). The lack of effective, less invasive therapies for developmental diseases highlights the need for animal models that replicate complex pathological phenotypes, while allowing scalable drug screening. Zebrafish high fecundity and rapid development enable efficient in vivo drug testing. We assessed zebrafish’s potential for studying PERK and its pharmacological modulation in developmental diseases like WRS.

To assess the similarity between human and zebrafish PERK we used bioinformatic analyses. To inhibit PERK we used GSK2606414. To evaluate effects on skeletal, neuromuscular, and cardiac development we combined behavioural and functional assays. To assess diabetic-like phenotypes we used fluorescent pancreatic markers and a glucose probe.

Zebrafish PERK conserves 11 of 12 critical GSK2606414‑binding residues (predicted 3D structures highly similar). Functionally, GSK2606414 (10 µM) decreased levels of PERK pathway markers and induced WRS-relevant phenotypes: reduced body length, increased trunk–tail curvature, decreased cranial cartilage staining; neuromuscular impairment (altered reflexes, reduced muscle birefringence) and cardiac dysfunction (pericardial oedema, reduced stroke volume and cardiac output). However, parameters not associated with WRS like otolith area and eye/body ratio remained unaffected. Moreover, GSK2606414 decreased 𝛽-cell mass and lowered 2-NBDG-glucose uptake in neuromasts, consistent with diabetic-like phenotypes.

These findings evidence zebrafish’s potential for studying PERK function and its pharmacological modulation in developmental disorders like WRS, aiding research on pathophysiology and experimental treatments.

The online version contains supplementary material available at 10.1007/s43440-026-00837-7.