Secreted phospholipase A2 group X regulates peripheral sensitization to allergen

Area of Science:

• Immunology
• Allergology
• Molecular Biology

Background:

• The "atopic march" describes the progression from allergic skin disease to allergic airway disease, with underlying molecular mechanisms unclear.
• Secreted phospholipase A2 group X (sPLA2-X) is linked to human asthma and influences airway hyperresponsiveness (AHR) and inflammation in mouse models.

Purpose of the Study:

• To investigate the role of sPLA2-X in the "atopic march" using a novel proteolytic allergen model.
• To determine if sPLA2-X facilitates peripheral allergen sensitization and subsequent airway dysfunction.

Main Methods:

• Developed a mouse model mimicking the "atopic march" with dermal sensitization and airway challenge using house dust mite (HDM).
• Utilized sPLA2-X knockout (Pla2g10-/-) mice and transgenic mice expressing human sPLA2-X.
• Administered a small molecule inhibitor (ROC0929) of sPLA2-X during the sensitization phase.

Main Results:

• Pla2g10-/- mice exhibited reduced AHR and lower airway eosinophil counts after HDM sensitization and challenge compared to wild-type (WT) mice.
• Inhibition of sPLA2-X in transgenic mice during sensitization led to attenuated AHR.
• sPLA2-X inhibition reduced lung tissue allergen-specific memory CD4+ T cells.

Conclusions:

• sPLA2-X functions as an endogenous adjuvant, enhancing peripheral allergic sensitization.
• Targeting sPLA2-X during the sensitization phase can modulate subsequent allergen-induced airway dysfunction, including AHR and inflammation.
• These findings support sPLA2-X inhibition as a potential strategy to prevent or treat allergic airway diseases.