Inhibition of interleukin-4-and CD40-induced IgE germline gene promoter activity by 2′-aminoethoxy-modified tripler-forming oligonucleotides

Elevated levels of IgE are intimately associated with a number of allergic diseases, such as allergic rhinitis or asthma, Therefore, prevention of IgE production in human B-cells represents an attractive therapeutic target. IL-8-induced IgE germline gene transcription represents a crucial early step during IgE isotype switch differentiation. Gene induction is orchestrated by the coordinated action of the transcription factors STAT6 (signal transducer and activator of transcription), NF-kappaB, PU.1, and C/EBP, This study shows that 2'-aminoethoxy-modified oligonucleotides, which partially overlap with the STAT6 and the adjacent PU.1/NF-kappaB binding site, inhibit DNA binding of all three proteins with high affinity in a dose- and time-dependent fashion in vitro. Loss of protein binding correlated strongly with increasing DNA tripler formation. Importantly, the oligomers also effectively displaced pre-bound recombinant NF-KB p50 from double-stranded DNA in vitro, Functionally, the oligonucleotides led to a selective inhibition of IL-4-induced reporter gene activity from a construct driven by the IgE germline gene promoter in human B-cells. These data confirm the critical role of this cytokine-responsive regulatory region in IgE germline gene induction and further support the concept of specific modulation of gene expression by DNA tripler formation induced with chemically modified oligonucleotides.