TNF-α–induced protein 3 is a key player in childhood asthma development and environment-mediated protection

Abstract

Background: Childhood asthma prevalence is significantly greater in urban areas compared with rural/farm environments. Murine studies have shown that TNF-α–induced protein 3 (TNFAIP3; A20), an anti-inflammatory regulator of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling, mediates environmentally induced asthma protection. Objective: We aimed to determine the role of TNFAIP3 for asthma development in childhood and the immunomodulatory effects of environmental factors. Methods: In a representative selection of 250 of 2168 children from 2 prospective birth cohorts and 2 cross-sectional studies, we analyzed blood cells of healthy and asthmatic children from urban and rural/farm environments from Europe and China. PBMCs were stimulated ex vivo with dust from “asthma-protective” farms or LPS. NF-κB signaling–related gene and protein expression was assessed in PBMCs and multiplex gene expression assays (NanoString Technologies) in isolated dendritic cells of schoolchildren and in cord blood mononuclear cells from newborns. Results: Anti-inflammatory TNFAIP3 gene and protein expression was consistently decreased, whereas proinflammatory Toll-like receptor 4 expression was increased in urban asthmatic patients (P