Osteologie 2019; 28(04): 289-290
DOI: 10.1055/s-0039-1700632
Abstracts
Georg Thieme Verlag KG Stuttgart · New York

Zebrafish as a model for hypophosphatasia

A Borst
1   Institute for Human Genetics, Biocenter, University of Würzburg, Germany
,
B Geidner
1   Institute for Human Genetics, Biocenter, University of Würzburg, Germany
2   Zoological Institute, University of Cologne, Germany
,
R Blümel
1   Institute for Human Genetics, Biocenter, University of Würzburg, Germany
,
E Klopocki
1   Institute for Human Genetics, Biocenter, University of Würzburg, Germany
,
F Jakob
3   Orthopedic Department for Musculoskeletal Research, University of Würzburg, Germany
,
D Liedtke
1   Institute for Human Genetics, Biocenter, University of Würzburg, Germany
,
S Graser
3   Orthopedic Department for Musculoskeletal Research, University of Würzburg, Germany
› Author Affiliations
Further Information

Publication History

Publication Date:
14 November 2019 (online)

 

Introduction:

Hypophosphatasia (HPP) is a rare hereditary disease due to mutations in the tissue-nonspecific alkaline phosphatase (TNAP) gene. HPP leads to severe dental and bone mineralization issues, craniosynostosis, and neurological disorders like epileptic seizures, anxiety, and depression. We established the zebrafish (Danio rerio) as in vivo model system for detailed investigations and visualization of tissue-specific effects in the context of craniosynostosis and neuronal symptoms of HPP.

Material and methods:

In order to elucidate TNAP expression, whole mount in situ hybridization (ISH) was performed at different stages in wildtype zebrafish embryos. Moreover, whole brains from adult fish were analyzed for TNAP expression via qPCR and combined TNAP-ISH/PCNA immunostaining. Additionally, activity-dependent ELF97® Phosphatase staining (Thermo Fisher Scientific) was performed on adult brain sections. Finally, in vivo alizarin-red stainings were established for analysis of craniosynostosis in the zebrafish model.

Results:

Positive TNAP-ISH signals were detected in all analyzed embryonal stages and in adult brain sections. Zebrafish embryos showed prominent TNAP expression in brain, nephros, retina, and fin. In the adult zebrafish brain, TNAP mRNA and activity could also be detected in restricted areas, among others in the amygdala, which implies its connection to anxiety disorders. Furthermore, alizarin-red staining of developing skull bone structures was successfully established for analysis of craniosynostosis.

Discussion:

For getting a detailed insight into nervous system and craniosynostosis related issues in HPP, we developed a zebrafish model system. Establishment of diverse molecular techniques paves the way for future tissue-specific investigations in order to get new molecular insights into consequences of TNAP mutations in vivo.

Key words:

Hypophosphatasia, TNAP, zebrafish, craniosynostosis

* D. Liedtke and S. Graser contributed equally to this work