Zebrafish Models to Study Ectopic Calcification and Calcium-Associated Pathologies

Abstract

Ectopic calcification refers to the pathological accumulation of calcium ions in soft tissues and is often the result of a dysregulated action or disrupted function of proteins involved in extracellular matrix mineralization. While the mouse has traditionally been the go-to model organism for the study of pathologies associated with abnormal calcium deposition, many mouse mutants often have exacerbated phenotypes and die prematurely, limiting the understanding of the disease and the development of effective therapies. Since the mechanisms underlying ectopic calcification share some analogy with those of bone formation, the zebrafish (Danio rerio)-a well-established model for studying osteogenesis and mineralogenesis-has recently gained momentum as a model to study ectopic calcification disorders. In this review, we outline the mechanisms of ectopic mineralization in zebrafish, provide insights into zebrafish mutants that share phenotypic similarities with human pathological mineralization disorders, list the compounds capable of rescuing mutant phenotypes, and describe current methods to induce and characterize ectopic calcification in zebrafish.

Keywords: calcium; disease modeling; ectopic calcification; mineralization; zebrafish.

Figure 1

Vascular calcification in six-month-old zebrafish exposed for fifteen days to 25 mg/L of sodium warfarin. (A) Alizarin red S in vivo staining of calcified caudal fin blood vessels (white arrows) and (B) von Kossa’s staining of a calcified artery counterstained with toluidine blue (white arrow). Bar is 500 µm in (A) and is 50 µm in (B).

Figure 2

Current models that are available to study ectopic and soft tissue calcification in zebrafish. Information reported here includes target genes, target tissues, and the onset of ectopic calcification observed in zebrafish mutants. Representative image of a zebrafish larvae at 5 dpf. dpf, days post-fertilization; mpf, months post-fertilization; MO, morpholino oligomer. * Morpholino-injected.