Equine keratinocytes in the pathogenesis of insect bite hypersensitivity: Just another brick in the wall?
Authors: Cvitas Iva, Oberhaensli Simone, Leeb Tosso, Marti Eliane
Journal: PloS one
Summary
# Editorial Summary: Equine Keratinocytes and Insect Bite Hypersensitivity Insect bite hypersensitivity remains the most prevalent dermatological condition in horses, yet the precise contribution of skin barrier cells to disease development remains incompletely understood. Cvitas and colleagues investigated how keratinocytes from IBH-affected and healthy horses respond to Culicoides allergens and inflammatory signals by analysing gene expression changes across both cell populations. Direct exposure to Culicoides allergens alone failed to trigger meaningful transcriptional responses; however, stimulation with an allergic cytokine milieu produced substantial shifts, including upregulation of chemokines (CCL5, -11, -20, -27) and the pruritic mediator IL-31, coupled with downregulation of barrier-integrity genes (SCEL and KRT16). Notably, IBH-affected keratinocytes showed minimal baseline differences from healthy controls, suggesting that pathological changes emerge through inflammatory signalling rather than intrinsic keratinocyte dysfunction. These findings suggest keratinocytes function as active participants in innate immunity and inflammatory amplification during IBH, likely perpetuating itch and immune cell recruitment once allergic sensitisation has occurred—a perspective that may inform therapeutic approaches targeting barrier function or cytokine-mediated signalling rather than allergen avoidance alone.
Read the full abstract on PubMed
Practical Takeaways
- •Keratinocyte barrier integrity in IBH is compromised by inflammatory cytokine environment rather than direct allergen contact, suggesting therapeutic focus should include reducing local inflammation alongside allergen avoidance
- •The innate immune response through TLR signaling appears important in IBH pathogenesis; strategies targeting epithelial barrier repair and immune modulation may be more effective than allergen-specific approaches alone
- •Since IBH-affected and healthy horses show similar baseline keratinocyte function, prevention and management should emphasize early intervention to prevent the shift toward allergic cytokine milieu
Key Findings
- •Keratinocytes from both IBH-affected and healthy horses showed minimal transcriptional response to direct Culicoides allergen stimulation alone
- •Allergic cytokine milieu induced significant upregulation of chemokines (CCL5, -11, -20, -27) and IL31, with concurrent downregulation of barrier proteins (SCEL, KRT16)
- •TLR-1/2 ligand stimulation activated genes involved in Toll-like receptor, NOD-receptor, and NF-κB signaling pathways
- •IBH-affected and healthy horse keratinocytes showed similar transcriptome profiles with minimal baseline differences, suggesting barrier dysfunction is context-dependent rather than constitutive