Targeting ADAM33 with oligonucleotides in complex mouse and human lung tissue explant culture models as a novel disease-modifying asthma therapy

<bold>Background:</bold> A Disintegrin And Metalloprotease (ADAM)33 is an asthma susceptibility and airway remodelling gene expressed in mesenchymal cells. Soluble ADAM33 is increased in asthmatic airways and induces airway remodelling. Adam33-null mice were protected from developing allergic asthma. Here, we test different anti-ADAM33 oligonucleotides (aA33Oligos) that specifically silence <italic>ADAM33</italic> mRNA, as a potential novel disease-modifying asthma therapy. <bold>Aim:</bold> To test the efficiency of aA33Oligos in <italic>ex-vivo</italic> mouse and human lung tissue explant (LTE) culture models for future <italic>in-vivo</italic> work. <bold>Methods:</bold> Mouse and human lungs (n=3) were collected after informed consent and dissected into ~8mm³ LTE pieces. These were cultured in the presence of 4 murine (0.11, 0.33, 1 or 3 nmol/ml) or 7 human (0.5, 1, 2 or 4 nmol/ml) aA33Oligos or non-targeting control for 3 and 7 days. <italic>ADAM33,</italic> remodelling and inflammatory gene expression were determined. <bold>Results:</bold> In murine LTE cultures, there was up to 80% and 70% suppression of <italic>Adam33</italic> (p<0.0001) at 3 nmol/ml of murine aA33Oligos at 3 and 7 days, respectively. In hLTEs cultured for 3 days, 6 out of 7 human aA33Oligos suppressed <italic>ADAM33</italic> by up to 75%, without affecting the remodelling genes <italic>ACTA2</italic> or <italic>COL1A1,</italic> or the inflammatory gene <italic>IL-6</italic>. <bold>Conclusion:</bold> Murine and human aA33Oligos successfully silence <italic>ADAM33</italic> expression by up to 70% in complex lung tissues ex vivo, without significant off-target effects. This will help us to select the most efficacious aA33Oligos for testing in preclinical mouse models of allergic asthma.