Regenerating zebrafish scales express a subset of evolutionary conserved genes involved in human skeletal disease

Dylan J. M. Bergen*, Qiao Tong, Ankit Shukla, Elis Newham, Jan Zethof, Mischa Lundberg, Rebecca Ryan, Scott E. Youlten, Monika Frysz, Peter I. Croucher, Gert Flik, Rebecca J. Richardson, John P. Kemp, Chrissy L. Hammond, Juriaan R. Metz*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

22 Citations (Scopus)
105 Downloads (Pure)

Abstract

Background
Scales are mineralised exoskeletal structures that are part of the dermal skeleton. Scales have been mostly lost during evolution of terrestrial vertebrates whilst bony fish have retained a mineralised dermal skeleton in the form of fin rays and scales. Each scale is a mineralised collagen plate that is decorated with both matrix-building and resorbing cells. When removed, an ontogenetic scale is quickly replaced following differentiation of the scale pocket-lining cells that regenerate a scale. Processes promoting de novo matrix formation and mineralisation initiated during scale regeneration are poorly understood. Therefore, we performed transcriptomic analysis to determine gene networks and their pathways involved in dermal scale regeneration.

Results
We defined the transcriptomic profiles of ontogenetic and regenerating scales of zebrafish and identified 604 differentially expressed genes (DEGs). These were enriched for extracellular matrix, ossification, and cell adhesion pathways, but not in enamel or dentin formation processes indicating that scales are reminiscent to bone. Hypergeometric tests involving monogenetic skeletal disorders showed that DEGs were strongly enriched for human orthologues that are mutated in low bone mass and abnormal bone mineralisation diseases (P< 2× 10−3). The DEGs were also enriched for human orthologues associated with polygenetic skeletal traits, including height (P< 6× 10−4), and estimated bone mineral density (eBMD, P< 2× 10−5). Zebrafish mutants of two human orthologues that were robustly associated with height (COL11A2, P=6× 10−24) or eBMD (SPP1, P=6× 10−20) showed both exo- and endo- skeletal abnormalities as predicted by our genetic association analyses; col11a2Y228X/Y228X mutants showed exoskeletal and endoskeletal features consistent with abnormal growth, whereas spp1P160X/P160X mutants predominantly showed mineralisation defects.

Conclusion
We show that scales have a strong osteogenic expression profile comparable to other elements of the dermal skeleton, enriched in genes that favour collagen matrix growth. Despite the many differences between scale and endoskeletal developmental processes, we also show that zebrafish scales express an evolutionarily conserved sub-population of genes that are relevant to human skeletal disease.
Original languageEnglish
Article number21
Number of pages25
JournalBMC Biology
Volume20
Issue number1
DOIs
Publication statusPublished - 21 Jan 2022

Bibliographical note

Funding Information:
DB and CH received Fellowship funding from Versus Arthritis (22044 and 21937 respectively). JM and GF were supported by the subsidy programme Smartmix (SSM06010) of the Dutch Ministries of Economic Affairs and Education, Culture and Science. JPK was funded by a National Health and Medical Research Council (Australia) Investigator grant (GNT1177938) and project grant (GNT1158758). ML is supported by a UQ Research Training Scholarship and the Commonwealth Scientific and Industrial Research Organisation Postgraduate Top-Up Scholarship. RR and RJR were supported by the BHF Oxbridge Centre of Regenerative Medicine (RM/17/2/33380) and a BHF Intermediate Fellowship to RJR (FS/15/2/31225).

Publisher Copyright:
© 2021, The Author(s).

Keywords

  • osteoanabolic
  • osteoblast
  • zebrafish
  • regeneration
  • transcriptome
  • genetics
  • transgenic
  • collagen
  • bone
  • musculoskeletal disorders

Fingerprint

Dive into the research topics of 'Regenerating zebrafish scales express a subset of evolutionary conserved genes involved in human skeletal disease'. Together they form a unique fingerprint.

Cite this