Zebrafish Tric-b is required for skeletal development and bone cells differentiation

Francesca Tonelli; Laura Leoni; Valentina Daponte; Roberta Gioia; Silvia Cotti; Imke A K Fiedler; Daria Larianova; Andy Willaert; Paul J Coucke; Simona Villani; Björn Busse; Roberta Besio; Antonio Rossi; P Eckhard Witten; Antonella Forlino

doi:10.3389/fendo.2023.1002914

Zebrafish Tric-b is required for skeletal development and bone cells differentiation

Front Endocrinol (Lausanne). 2023 Jan 23:14:1002914. doi: 10.3389/fendo.2023.1002914. eCollection 2023.

Authors

Affiliations

¹ Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy.
² Department of Biology, Ghent University, Ghent, Belgium.
³ Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
⁴ Department of Biomolecular Medicine, Center of Medical Genetics, Ghent University-University Hospital, Ghent, Belgium.
⁵ Department of Public Health and Experimental and Forensic Medicine, Unit of Biostatistics and Clinical Epidemiology, University of Pavia, Pavia, Italy.

Abstract

Introduction: Trimeric intracellular potassium channels TRIC-A and -B are endoplasmic reticulum (ER) integral membrane proteins, involved in the regulation of calcium release mediated by ryanodine (RyRs) and inositol 1,4,5-trisphosphate (IP₃Rs) receptors, respectively. While TRIC-A is mainly expressed in excitable cells, TRIC-B is ubiquitously distributed at moderate level. TRIC-B deficiency causes a dysregulation of calcium flux from the ER, which impacts on multiple collagen specific chaperones and modifying enzymatic activity, leading to a rare form of osteogenesis imperfecta (OI Type XIV). The relevance of TRIC-B on cell homeostasis and the molecular mechanism behind the disease are still unknown.

Results: In this study, we exploited zebrafish to elucidate the role of TRIC-B in skeletal tissue. We demonstrated, for the first time, that tmem38a and tmem38b genes encoding Tric-a and -b, respectively are expressed at early developmental stages in zebrafish, but only the latter has a maternal expression. Two zebrafish mutants for tmem38b were generated by CRISPR/Cas9, one carrying an out of frame mutation introducing a premature stop codon (tmem38b^-/- ) and one with an in frame deletion that removes the highly conserved KEV domain (tmem38b^{Δ120-7/Δ120-7} ). In both models collagen type I is under-modified and partially intracellularly retained in the endoplasmic reticulum, as described in individuals affected by OI type XIV. Tmem38b^-/- showed a mild skeletal phenotype at the late larval and juvenile stages of development whereas tmem38b^{Δ120-7/Δ120-7} bone outcome was limited to a reduced vertebral length at 21 dpf. A caudal fin regeneration study pointed towards impaired activity of osteoblasts and osteoclasts associated with mineralization impairment.

Discussion: Our data support the requirement of Tric-b during early development and for bone cell differentiation.

Keywords: TRIC-B; bone; collagen; endoplasmic reticulum; fin regeneration; osteogenesis imperfecta; zebrafish.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Bone and Bones / metabolism
Calcium / metabolism
Cell Differentiation / genetics
Ion Channels* / genetics
Osteogenesis Imperfecta* / genetics
Zebrafish Proteins* / genetics
Zebrafish* / metabolism

Substances

Calcium
Ion Channels
Zebrafish Proteins

Grants and funding

This research was funded by a Grant of the Italian Ministry of Education, University and Research (MIUR) to the Department of Molecular Medicine of the University of Pavia under the initiative “Dipartimenti di Eccellenza (2018–2022)” and Telethon Exploratory Grant GEP15066 to AF. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.