Proteomic signatures of equine dental tooth tissues in ageing and disease.

BACKGROUND

Ageing and dental disease in horses lead to structural and functional deterioration of dental tissues, yet their molecular signatures remain poorly characterised. Understanding how these processes alter the protein composition of enamel, dentin, cementum and pulp is essential for improving equine oral health and identifying biomarkers of degeneration.

OBJECTIVES

To characterise the proteomic profiles of equine dental tissues and determine age- and disease-associated changes, with the aim of identifying proteins consistently altered across conditions.

STUDY

DESIGN

Ex vivo proteomic study.

METHODS

Fifteen equine cheek teeth were allocated to three groups (n = 5/group): mature adult, old and diseased. Label-free quantitative mass spectrometry was used to profile proteins across enamel, dentin, cementum and pulp. Differential abundance analysis and clustering assessed age- and disease-related effects. A Shiny-based interactive tool was developed for data exploration.

RESULTS

A total of 1950 proteins were identified, with 58% unique to dental pulp. Ageing affected 329 proteins across all tissues, while disease impacted 379. Ageing consistently disrupted extracellular matrix (ECM) homeostasis in hard tissues. Cementum demonstrated increased catabolic markers the metalloproteinases -2 and -13. In dentin, the mineralisation protein dentin sialophosphoprotein was significantly reduced with age. Altered proteins in diseased pulp demonstrated predicted inhibition of ECM organisation (z-score = -3.05, p = 0.032) and elastic fibre formation (z-score = -2.82, p = 0.0033), while retinoic acid receptor activation was increased (z-score = 2.11, p = 0.006). Similarity analysis revealed overlapping molecular responses between ageing and disease.

MAIN LIMITATIONS: Small sample size and inclusion of only cheek teeth limit generalisability. Proteomic findings require functional validation.

CONCLUSIONS

Ageing and disease induce distinct yet overlapping proteomic alterations in equine dental tissues, primarily affecting ECM homeostasis. A subset of consistently altered proteins may serve as targets for regenerative strategies, with implications for improving equine dental health and welfare.