A zebrafish model of NEXMIF-related encephalopathy identified drivers of hyperlocomotion and provides a scalable platform for drug discovery.
4 affiliations
- 1Departamento de Biología Celular e Histología, Facultad de Biología, Universidad de Murcia, Murcia, Spain.
- 2Instituto Murciano de Investigación Biosanitaria (IMIB-Pascual Parrilla), Murcia, Spain.
- 3Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain.
- 4Hospital Clínico Universitario Virgen de la Arrixaca, Murcia, Spain.
Abstract
X-linked Intellectual Disability type 98 (XLID-98) is a neurodevelopmental disorder with a broad phenotypic spectrum caused by pathogenic variants in the neurite extension and migration factor (NEXMIF) gene, formerly known as KIAA2022, KIDLIA, or XPN (OMIM 300524). To investigate the pathogenic mechanisms of XLID-98, a double knock-out zebrafish model (nexmifa/b -/-) was generated using CRISPR/Cas9 technology. Mutant larvae displayed limited morphological abnormalities, the most notable being an increase in total body length. They also exhibited a significant hyperlocomotor phenotype in the visual-startle OFF assay, which was attenuated by treatment with sodium valproate (VPA) and topiramate, thereby supporting the pharmacological validity of the model. Transcriptomic analysis of larval heads at seven dpf revealed 414 differentially expressed genes enriched in mitogen-activated protein kinase (MAPK) signaling, cell adhesion, and sodium transport pathways. Functional analyses demonstrated that simultaneous CRISPR/Cas9-mediated disruption of the upregulated genes entpd3 (ectonucleoside triphosphate diphosphohydrolase 3) and ddx43 (DEAD-box helicase 43) exacerbated the hyperlocomotor phenotype, suggesting that these genes may participate in a compensatory response, whereas reduced kbtbd7 (kelch repeat and BTB domain-containing protein 7) activity may contribute to phenotype severity. A targeted screen of 87 natural compounds identified kahweol acetate, veratridine, and rauwolscine as potent inducers of entpd3. However, despite robust transcriptional activation, rauwolscine failed to improve behavioral outcomes, suggesting that modulation of a single molecular target may be insufficient for phenotypic rescue. Collectively, these findings establish the first zebrafish model of NEXMIF-related encephalopathy, identify entpd3, ddx43, and kbtbd7 as candidate modulators of this behavioral phenotype, and provide a scalable platform for targeted therapeutic discovery in XLID-98.
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BibTeX
@article{bernalbermudez2026zebrafish,
title = {{A zebrafish model of NEXMIF-related encephalopathy identified drivers of hyperlocomotion and provides a scalable platform for drug discovery.}},
author = {Beatriz Bernal-Bermúdez and Francisco J Martínez-Morcillo and Inmaculada Fuentes-Martínez and Alicia Martínez-López and María L Cayuela and Victoriano Mulero and Diana García-Moreno},
journal = {Frontiers in cell and developmental biology},
year = {2026},
month = oct,
doi = {10.3389/fcell.2026.1899363},
url = {https://europepmc.org/article/MED/42923324},
note = {CC BY},
}
RIS
TY - JOUR
TI - A zebrafish model of NEXMIF-related encephalopathy identified drivers of hyperlocomotion and provides a scalable platform for drug discovery.
AU - Beatriz Bernal-Bermúdez
AU - Francisco J Martínez-Morcillo
AU - Inmaculada Fuentes-Martínez
AU - Alicia Martínez-López
AU - María L Cayuela
AU - Victoriano Mulero
AU - Diana García-Moreno
PY - 2026
DA - 2026/10/08
JO - Frontiers in cell and developmental biology
DO - 10.3389/fcell.2026.1899363
UR - https://europepmc.org/article/MED/42923324
AB - X-linked Intellectual Disability type 98 (XLID-98) is a neurodevelopmental disorder with a broad phenotypic spectrum caused by pathogenic variants in the neurite extension and migration factor (NEXMIF) gene, formerly known as KIAA2022, KIDLIA, or XPN (OMIM 300524). To investigate the pathogenic mechanisms of XLID-98, a double knock-out zebrafish model (nexmifa/b -/-) was generated using CRISPR/Cas9 technology. Mutant larvae displayed limited morphological abnormalities, the most notable being an increase in total body length. They also exhibited a significant hyperlocomotor phenotype in the visual-startle OFF assay, which was attenuated by treatment with sodium valproate (VPA) and topiramate, thereby supporting the pharmacological validity of the model. Transcriptomic analysis of larval heads at seven dpf revealed 414 differentially expressed genes enriched in mitogen-activated protein kinase (MAPK) signaling, cell adhesion, and sodium transport pathways. Functional analyses demonstrated that simultaneous CRISPR/Cas9-mediated disruption of the upregulated genes entpd3 (ectonucleoside triphosphate diphosphohydrolase 3) and ddx43 (DEAD-box helicase 43) exacerbated the hyperlocomotor phenotype, suggesting that these genes may participate in a compensatory response, whereas reduced kbtbd7 (kelch repeat and BTB domain-containing protein 7) activity may contribute to phenotype severity. A targeted screen of 87 natural compounds identified kahweol acetate, veratridine, and rauwolscine as potent inducers of entpd3. However, despite robust transcriptional activation, rauwolscine failed to improve behavioral outcomes, suggesting that modulation of a single molecular target may be insufficient for phenotypic rescue. Collectively, these findings establish the first zebrafish model of NEXMIF-related encephalopathy, identify entpd3, ddx43, and kbtbd7 as candidate modulators of this behavioral phenotype, and provide a scalable platform for targeted therapeutic discovery in XLID-98.
SN - 2296-634X
ER -