Salivary Scavenger and Agglutinin (SALSA) Is Expressed in Mucosal Epithelial Cells and Decreased in Bronchial Epithelium of Asthmatic Horses.
Authors: Lee Gary Kwok Cheong, Tessier Laurence, Bienzle Dorothee
Journal: Frontiers in veterinary science
Summary
# Editorial Summary SALSA (Salivary Scavenger and Agglutinin) is an innate immune protein involved in inflammation regulation and tissue remodelling, yet its role in equine respiratory disease remained poorly characterised. Kwok Cheong and colleagues used immunohistochemistry on tissue samples from four horses, quantitative PCR analysis of bronchial biopsies from twelve horses (six asthmatic, six non-asthmatic), and molecular sequencing to map SALSA expression patterns and structural composition. The researchers identified SALSA protein throughout mucosal epithelial surfaces—particularly the respiratory tract, gastrointestinal tract and salivary glands—concentrated in apical epithelial cell regions consistent with secretion, and critically, found significantly lower gene expression in asthmatic versus healthy horses (p = 0.031). Equine SALSA exists in multiple isoforms containing three to five scavenger receptor cysteine-rich domains alongside CUB and Zona Pellucida domains, all mediating innate immune ligand binding. For practitioners, these findings suggest that impaired SALSA production may compromise mucosal immune competence in horses with severe asthma, potentially opening new therapeutic avenues targeting innate immunity rather than inflammation alone, though further investigation into how SALSA isoform variation correlates with disease severity and response to treatment would strengthen clinical application.
Read the full abstract on PubMed
Practical Takeaways
- •Asthmatic horses show measurable defects in a key innate immune protein (SALSA) at the bronchial epithelial level, which may explain their reduced ability to control airway inflammation
- •SALSA's multiple isoforms across horses suggest genetic variation in immune competence that could influence individual asthma susceptibility and severity
- •Understanding SALSA's role in mucosal immunity may open new therapeutic targets for managing equine asthma beyond current anti-inflammatory approaches
Key Findings
- •SALSA protein is expressed in mucosal epithelial cells across multiple tissues (trachea, bronchi, stomach, intestine, bladder) with strongest expression in duodenum and salivary gland ducts
- •Gene expression of SALSA was significantly lower in asthmatic compared to non-asthmatic horses (p = 0.031)
- •Equine SALSA contains 3-5 SRCR domains, 2 CUB domains, and 1 Zona Pellucida domain with multiple isoforms identified across different horses
- •Decreased SALSA expression in asthmatic horses suggests altered innate immunity and impaired mucosal immune regulation in equine asthma