Rapid-Throughput Skeletal Phenotyping of 100 Knockout Mice Identifies 9 New Genes That Determine Bone Strength

Abstract

Osteoporosis is a common polygenic disease and global healthcare priority but its genetic basis remains largely unknown. We report a high-throughput multi-parameter phenotype screen to identify functionally significant skeletal phenotypes in mice generated by the Wellcome Trust Sanger Institute Mouse Genetics Project and discover novel genes that may be involved in the pathogenesis of osteoporosis. The integrated use of primary phenotype data with quantitative x-ray microradiography, micro-computed tomography, statistical approaches and biomechanical testing in 100 unselected knockout mouse strains identified nine new genetic determinants of bone mass and strength. These nine new genes include five whose deletion results in low bone mass and four whose deletion results in high bone mass. None of the nine genes have been implicated previously in skeletal disorders and detailed analysis of the biomechanical consequences of their deletion revealed a novel functional classification of bone structure and strength. The organ-specific and disease-focused strategy described in this study can be applied to any biological system or tractable polygenic disease, thus providing a general basis to define gene function in a system-specific manner. Application of the approach to diseases affecting other physiological systems will help to realize the full potential of the International Mouse Phenotyping Consortium.

Development of an efficient screening system to identify novel bone metabolism-related genes using the exchangeable gene trap mutagenesis mouse models

“…reported nine novel genes related to bone metabolism from 100 randomly selected lines of gene-knockout mice from the Wellcome Trust Sanger Institute Mouse Genetics Project, and their method was determined to be extremely efficient14. In the present study, we selected 52 gene trap lines in the first screening that were considered to have high bone tissue specificity using “EST profile”, “X-gal”, “Related article”, and “Novel gene”.…”

“…compared each line of gene-knockout mice with normal reference mean data obtained from 77 WT mice14. In the current study, we placed emphasis on standardizing the background of the trapped genes among the genotypes in each line and then compared littermate mice in our screening.…”

“…To date, little has been reported on a screening method using mutant mouse strains to identify causative molecules in metabolic bone disease14. In the current study, we report on the development of an efficient screening system to identify novel genes involved in bone metabolism using mutant mouse strains established with the exchangeable gene trap method based on the EGTC database (Fig.…”

Musculoskeletal system

“…A range of nonhistological techniques including micro-CT, X-ray analysis, DEXA analysis of bone mineral density, biochemical analysis for mineral metabolism, breaking strength testing and muscle biomarkers can be used to screen for, or investigate, suspected musculoskeletal phenotypes (Bassett et al 2012). Differential staining of whole foetuses with Alizarin red for bone and Alcian blue for cartilage can be used to map alterations in early bone development (McLeod 1980).…”

Genetics of osteoporosis and bone disease (ASBMR 2012)

“…This group has been broadly phenotyping all mice going through the Sanger Institute Mouse Genetics Project and in doing so has identified nine genes previously not known to have a function in bone. 10 Hypothesis-free phenotyping projects such as this one have true potential to shift the study of bone biology in a major way, as they do not focus on a cell type or pathway, but rather attempt to catch all.…”