Osteoblast Production by Reserved Progenitor Cells in Zebrafish Bone Regeneration and Maintenance

Publication date: Available online 2 November 2017
Source:Developmental Cell
Author(s): Kazunori Ando, Eri Shibata, Stefan Hans, Michael Brand, Atsushi Kawakami
Mammals cannot re-form heavily damaged bones as in large fracture gaps, whereas zebrafish efficiently regenerate bones even after amputation of appendages. However, the source of osteoblasts that mediate appendage regeneration is controversial. Several studies in zebrafish have shown that osteoblasts are generated by dedifferentiation of existing osteoblasts at injured sites, but other observations suggest that de novo production of osteoblasts also occurs. In this study, we found from cell-lineage tracing and ablation experiments that a group of cells reserved in niches serves as osteoblast progenitor cells (OPCs) and has a significant role in fin ray regeneration. Besides regeneration, OPCs also supply osteoblasts for normal bone maintenance. We further showed that OPCs are derived from embryonic somites, as is the case with embryonic osteoblasts, and are replenished from mesenchymal precursors in adult zebrafish. Our findings reveal that reserved progenitors are a significant and complementary source of osteoblasts for zebrafish bone regeneration.

Graphical abstract

Teaser

Ando et al. identify osteoblast progenitor cells (OPCs) in zebrafish and find that OPCs are derived from embryonic somites and are reserved in niches of bone-forming tissues while being replenished from mesenchymal precursors. OPCs migrate from the niches and generate osteoblasts during bone regeneration and maintenance in adult zebrafish.


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