A Functional Single-Nucleotide Polymorphism Upstream of the Collagen Type III Gene Is Associated with Catastrophic Fracture Risk in Thoroughbred Horses
by
, , , and
Esther Palomino Lago
1
,
Arabella Baird
2,
Sarah C. Blott
3,
Rhona E. McPhail
2,
Amy C. Ross
1,
Sian A. Durward-Akhurst
4 and
Deborah J. Guest
1,*
1
Department of Clinical Sciences and Services, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK
2
Animal Health Trust, Lanwades Park, Kentford, Newmarket CB8 7UU, UK
3
School of Veterinary Medicine and Science, University of Nottingham, Nottingham LE12 5RD, UK
4
Department of Veterinary Clinical Sciences, University of Minnesota, Saint Paul, MN 55108, USA
*
Author to whom correspondence should be addressed.
Animals 2024, 14(1), 116; https://doi.org/10.3390/ani14010116
Submission received: 16 November 2023
/
Revised: 22 December 2023
/
Accepted: 25 December 2023
/
Published: 28 December 2023
(This article belongs to the Special Issue Advances in Equine Genetics and Breeding)
Simple Summary
Bone fractures are a major welfare concern in Thoroughbred racehorses and often lead to euthanasia. In this study, we established a cell model to investigate the genetic factors involved in fracture risk. We found that collagen type III is expressed at lower levels in cells from horses with a high genetic risk of fracture and identified a novel DNA variant that is significantly associated with fracture and can affect the expression level of collagen type III.
Abstract
Fractures caused by bone overloading are a leading cause of euthanasia in Thoroughbred racehorses. The risk of fatal fracture has been shown to be influenced by both environmental and genetic factors but, to date, no specific genetic mechanisms underpinning fractures have been identified. In this study, we utilised a genome-wide polygenic risk score to establish an in vitro cell system to study bone gene regulation in horses at high and low genetic risk of fracture. Candidate gene expression analysis revealed differential expression of COL3A1 and STAT1 genes in osteoblasts derived from high- and low-risk horses. Whole-genome sequencing of two fracture cases and two control horses revealed a single-nucleotide polymorphism (SNP) upstream of COL3A1 that was confirmed in a larger cohort to be significantly associated with fractures. Bioinformatics tools predicted that this SNP may impact the binding of the transcription factor SOX11. Gene modulation demonstrated SOX11 is upstream of COL3A1, and the region binds to nuclear proteins. Furthermore, luciferase assays demonstrated that the region containing the SNP has promoter activity. However, the specific effect of the SNP depends on the broader genetic background of the cells and suggests other factors may also be involved in regulating COL3A1 expression. In conclusion, we have identified a novel SNP that is significantly associated with fracture risk and provide new insights into the regulation of the COL3A1 gene.
Keywords:
fracture risk; horse; genetic variation; bone; osteoblast; in vitro model
