Bone Phenotyping Approaches in Human, Mice and Zebrafish – Expert Overview of the EU Cost Action GEMSTONE (“GEnomics of MusculoSkeletal traits TranslatiOnal NEtwork”)

Abstract

A synoptic overview of scientific methods applied in bone and associated research fields across species has yet to be published. Experts from the EU Cost Action GEMSTONE (“GEnomics of MusculoSkeletal Traits translational Network”) Working Group 2 present an overview of the routine techniques as well as clinical and research approaches employed to characterize bone phenotypes in humans and selected animal models (mice and zebrafish) of health and disease. The goal is consolidation of knowledge and a map for future research. This expert paper provides a comprehensive overview of state-of-the-art technologies to investigate bone properties in humans and animals – including their strengths and weaknesses. New research methodologies are outlined and future strategies are discussed to combine phenotypic with rapidly developing –omics data in order to advance musculoskeletal research and move towards “personalised medicine”.

Functional Validation of Osteoporosis Genetic Findings Using Small Fish Models

“…To date, even with the advanced Mouse KO and phenotyping collaborations, such as the International Mouse Phenotyping Consortium [ 75 ] and the Origins of Bone and Cartilage Disease consortium [ 76 ], only a minority of these genes were tested for relevance to increased bone fragility. Reaching such an objective requires a systematic prioritization and standardized phenotyping, which in turn asks for additional collaborative efforts, as outlined in the recent efforts from GEMSTONE Consortium [ 40 , 77 ]. Furthermore, with a large number of associated BMD loci and number of genes to be functionally validated, along with the labor, time and high costs for generation of new mice knockouts, mice are impractical models for parallel functional throughput evaluation of candidate genes.…”

“…Adult zebrafish models to study osteoporosis have only been developed recently, alongside the study of the ageing zebrafish spine [ 92 , 173 , 174 ]. The similarity between the techniques and interpretation of the fish, mouse, and human skeletal phenotyping was recently described [ 77 ], as well as the necessity to reach a consensus and prepare guidelines for standard measurement of the small-fish OP-related measurements. Recently, Kague et al provided strong support of osteoporosis modeling in zebrafish, showing that aged zebrafish spines display increased susceptibility to fractures and have bone quality deterioration (tendency towards reduction of BMD, increased bone mineral heterogeneity and poor collagen organization) reminiscent of osteoporosis in mammalian models [ 92 ].…”

“…The endpoint of osteoporosis is the occurrence of a fracture. While the prediction of fractures in zebrafish is not comparable to that of humans, where FRAX (fracture assessment tool) is used; genetically modified zebrafish offer alternative ways to study fracture occurrence, prediction and fracture healing [ 77 ]. The zebrafish bony fin rays, known by fish experts as lepidotrichia, are under dynamic mechanical load during the fish swim, and are regions of interest to monitor bone fractures.…”

The genetic overlap between osteoporosis and craniosynostosis

“…While tools for the prediction of fractures risk in zebrafish have not been developed yet, genetically modified zebrafish offer alternative ways to study fracture occurrence, prediction, and fracture healing ( 135 , 136 ). Due to buoyance in the aquatic environment, fish are subjected to a lower mechanical load than terrestrial species.…”

Whole Genome Sequencing Unravels New Genetic Determinants of Early-Onset Familial Osteoporosis and Low BMD in Malta

“…Osteoporosis is a complex, metabolic skeletal disease characterised by a reduction in bone mass and impaired bone microarchitecture resulting in increased bone fragility [ 1 , 2 ]. Bone mineral density (BMD) measurement by dual-energy X-ray absorptiometry (DXA) remains the accepted gold-standard for the non-invasive diagnosis of osteoporosis [ 3 , 4 ]. Fractures are the major clinical consequence of osteoporosis, with those of the hip, vertebrae, humerus and wrist being the most common, debilitating and costly.…”