Distinct Roles Between Eotaxin 1 and Eotaxin 2 in Asthmatic Airways

Area of Science:

• Immunology
• Pulmonology
• Cell Biology

Background:

• Eotaxins (EOTs) are key chemoattractants for eosinophils in asthma.
• Their precise roles beyond eosinophil recruitment in severe asthma remain unclear.
• Investigating distinct EOT functions is crucial for understanding asthma pathogenesis.

Purpose of the Study:

• To elucidate the differential roles of Eotaxin-1 (EOT1) and Eotaxin-2 (EOT2) in severe asthma.
• To analyze the association of EOT levels with clinical characteristics and inflammatory markers.
• To investigate the in vivo and in vitro functions of EOT1 and EOT2 in asthma models.

Main Methods:

• Serum levels of EOT1, EOT2, MPO, MMP-9, TIMP-1, and ECP were measured in 79 adult asthmatics.
• Clinical data were analyzed based on inflammatory phenotype, disease severity, and EOT levels.
• In vivo studies involved intranasal administration of EOT1/EOT2 and neutralizing antibodies in a mouse asthma model.

Main Results:

• Higher serum EOT1 and EOT2 levels were observed in severe asthma patients.
• EOT1 correlated with eosinophil counts and ECP, while EOT2 correlated with MPO, MMP-9, TIMP-1, and reduced lung function.
• In mice, EOT1 increased eosinophils and IL-5, whereas EOT2 induced neutrophil activation, airway remodeling, and epithelial-to-mesenchymal transition.

Conclusions:

• EOT1 promotes T2/eosinophilic inflammation.
• EOT2 accelerates airway remodeling and lung function decline via neutrophil activation.
• These findings reveal distinct pathogenic roles for EOTs in severe asthma.