IntroductionBlood inflammatory-like eosinophils (iEOS-like) and resident-like eosinophils (rEOS-like) could differently affect airway smooth muscle cells (ASMC) behavior, contributing to airway remodeling in asthma.

AimTo investigate eosinophil subtypes effect on ASMC migration, extracellular matrix (ECM)-related proliferation and COL1A1, FN,TGF-?1, contractile apparatus gene expression in asthma.

MethodsWe included 17 non-severe allergic asthma (AA), 15 severe eosinophilic asthma (SEA) patients and 12 healthy control subjects (HS). Blood eosinophils were isolated using high-density Ficoll centrifugation and magnetic separation, then subtyped using magnetic separation against L-selectin. ASMC migration after 72h incubation was evaluated by wound healing assay, gene expression by RT-PCR analysis and ASMC proliferation on their secreted ECM by AlamarBlue assay.

ResultsEosinophil subtypes from all study groups significantly promoted migration of ASMC compared to control ASMC (p<0.05). ASMC migration, ECM-related proliferation and COL1A1, FN, TGF-?1, smooth muscle (sm)-MLCK, sm-MHC, SM22, ?-sm-actin gene expression in ASMC after incubation with AA and SEA patients' eosinophil subtypes significantly increased compared to HS group (p<0.05). Moreover, rEOS-like cells effect on ASMC migration, ECM-related proliferation and FN, sm-MHC and SM22 gene expression in ASMC was higher than iEOS-like cells (p<0.05) in asthma groups, and SEA eosinophils demonstrated the highest effect (p<0.05).

ConclusionsIn asthma, both eosinophil subtypes, particularly rEOS-like cells, promote ASMC migration, ECM-related proliferation and upregulate FN, sm-MHC andSM22 gene expression in ASMC.