TLR 7/8 regulates Type I and Type III Interferon Signalling in RV1b induced Allergic Asthma

QuestionInterferon responses have been reported to be defective in rhinovirus (RV) induced asthma. The heterodimeric receptor of type I Interferon (IFN) (IFN-α/-β) is composed by IFNαR-1 and IFNαR-2. Ligand binding to the IFN-α/-β receptor complex activates STAT1 and STAT2 intracellularly. Although type III Interferon (IFN-λ) binds to a different receptor containing IFNλRA and IL-10R2, its triggering leads to activation of the same downstream transcription factors. Here we analysed the effects of Rhinovirus to Interferon type I and III receptors and asked about possible Toll-like receptor 7/8 agonist R848 mediated IFNαR1 and IFNλRα regulation.MethodsWe measured IFN-α, -β, -λ and their receptor levels in PBMCs supernatants and cell pellets stimulated with RV1b and the Toll-like Receptor 7/8 (TLR7/8) agonist (R848), in two cohorts of children with and without asthma recruited at preschool age (PreDicta) and at primary school age (AGENDAS) as well as in cell supernatants from total lung cells isolated from mice.ResultsWe observed that R848 induced IFNλR mRNA expression in PBMCs of healthy and asthmatic children, but suppressed the IFNαR mRNA levels. In murine lung cells, RV1balone and together with R848 suppressed IFNαR protein in T cells compared to controls and in total lung IFNλR mRNA compared to RV1b infection alone.AnswerIn PBMCs from pre-school children, IFNαR mRNA was reduced and IFNλRα mRNA was induced upon treatment with TLR7/8 agonist thus suggesting new avenues for induction of anti-viral immune responses in pediatric asthma.