Differential Gene Expression Profiles and Selected Cytokine Protein Analysis of Mediastinal Lymph Nodes of Horses with Chronic Recurrent Airway Obstruction (RAO) Support an Interleukin-17 Immune Response.
Authors: Korn Alexandra, Miller Donald, Dong Lynn, Buckles Elizabeth Louise, Wagner Bettina, Ainsworth Dorothy Marie
Journal: PloS one
Summary
# Editorial Summary: IL-17 Immunity in Equine Recurrent Airway Obstruction Chronic recurrent airway obstruction (RAO) in horses exposed to hay dust shares striking similarities with occupational asthma in humans, yet the underlying immune mechanisms driving this persistent neutrophilic airway inflammation remain poorly defined. Korn and colleagues investigated the immunological basis of RAO by performing global gene expression profiling on mediastinal lymph nodes—the lymphoid tissue that drains the lungs—from affected and control horses, complemented by immunohistochemical and protein analyses. Over 200 genes showed differential expression patterns in RAO-affected horses, with pathway analysis centring on interleukin-17 (IL-17) signalling through the NF-κB transcription factor; tissue staining confirmed increased IL-17 protein in diseased lymph nodes (alongside downregulation of anti-inflammatory IL-4), suggesting a shift towards a Th17-polarised immune response. The findings implicate IL-17-mediated immunity as a key driver of RAO's chronic phase, pointing towards potential therapeutic targets that could benefit both equine patients and human occupational asthma sufferers, though further work is needed to identify which immune cell populations are producing the IL-17 in this disease model.
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Practical Takeaways
- •RAO involves a dysregulated immune response centered on IL-17 signaling, which may open new therapeutic targets beyond current management strategies focused on environmental control and bronchodilation
- •Understanding the IL-17 immune pathway in RAO could lead to development of targeted immunomodulatory treatments to reduce chronic airway inflammation in affected horses
- •This research bridges equine and human occupational asthma models, suggesting findings may have translational applications for managing both conditions
Key Findings
- •Differential expression of >200 genes in mediastinal lymph nodes of RAO-affected horses, with network analysis supporting IL-17 response centered on NF-κB
- •Increased IL-17 staining intensity demonstrated in mediastinal lymph node sections of diseased horses via immunohistochemical analysis
- •IL-17 concentrations elevated in lymph node homogenates from RAO-affected horses with concurrent down-regulation of IL-4 gene and protein expression
- •Gene expression and cytokine profiles support IL-17-mediated immune response as mechanism underlying chronic RAO pathogenesis