The expression of equine keratins K42 and K124 is restricted to the hoof epidermal lamellae of Equus caballus.
Authors: Armstrong Caitlin, Cassimeris Lynne, Da Silva Santos Claire, Micoogullari Yagmur, Wagner Bettina, Babasyan Susanna, Brooks Samantha, Galantino-Homer Hannah
Journal: PloS one
Summary
# Editorial Summary The structural integrity of the equine hoof lamellae—those intricate primary and secondary folds that maximise the dermoepidermal junction—underpins soundness, yet our molecular understanding of lamellar-specific tissues remains incomplete. Armstrong and colleagues investigated two keratin proteins, K42 and K124, which represent the predominant keratins in equine lamellar tissue, hypothesising that their restricted expression patterns could serve as reliable markers for lamellar differentiation and disease states such as laminitis. Using RT-PCR and in situ hybridisation, the researchers demonstrated that whilst KRT42 and KRT124 genes were expressed exclusively in lamellar tissue and absent from cornea, haired skin and coronet, K124 localised specifically to suprabasal cells with an abrupt transition occurring at the coronet–lamellae boundary. The team successfully generated and validated monoclonal antibodies against K124 peptides that showed no cross-reactivity with proteins from non-lamellar tissues, establishing K124 as the first definitively characterised lamellar-specific keratin in horses. For practitioners, these findings provide a molecular toolkit for investigating lamellar pathology; K124 antibodies could enable more precise identification of lamellar tissue involvement in laminitis cases and potentially aid in distinguishing primary lamellar disease from secondary structural changes, whilst opening avenues for future research into keratin expression changes during acute and chronic laminitis episodes.
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Practical Takeaways
- •K124 monoclonal antibodies provide a new diagnostic tool to specifically identify and study lamellar tissue pathology in laminitis and other hoof diseases
- •The lamellar specificity of K124 could enable earlier detection of lamellar damage or dysfunction before clinical signs of laminitis appear
- •These keratin markers may help differentiate primary lamellar disease from secondary changes in other hoof structures when evaluating chronic hoof problems
Key Findings
- •K42 and K124 keratins are highly abundant and restricted to equine hoof epidermal lamellae, absent from cornea, haired skin, and hoof coronet
- •KRT124 expression localizes to suprabasal and basal cells of lamellae with an abrupt transition from negative coronet tissue to positive proximal lamellae
- •Monoclonal antibodies against K124 were successfully generated and show no cross-reactivity with keratins from other equine epithelial tissues
- •K124 represents the first validated hoof lamellar-specific keratin marker that could serve as a differentiation and disease-specific indicator