Non-invasive strategy: Developing a topical IL-4Rα-specific nanobody for the treatment of allergic airway diseases

Inhibiting IL-4 and IL-13 are critical cytokines that induce the pathogenic responses of allergic airway diseases. Currently, monoclonal antibodies targeting IL-4Rα are administered subcutaneously to treat eosinophilic rhinosinusitis and allergic asthma. However, these treatments have several drawbacks. To address these issues, we have developed a novel IL-4Rα-targeting nanobody designed for non-invasive delivery to local inflammatory sites in allergic airway diseases. H5, selected via the ribosomal display applied screening from synthetic nanobody library, underwent dimerization and in-silico affinity maturation using AlphaFold2 and GROMACS resulting in a substantial/dramatic enhancement of its binding affinity. H5 effectively controlled inflammatory markers such as MUC5AC, CCL26, and FOXJ1 in human nasal epithelial cells (HNECs) by inhibiting IL-4 and IL-13 signaling. The bivalent form of H5 showed efficacy in easily accessible cells, such as multi-ciliated cells, while the monovalent variant targeted hard-to-reach cells, such as basal cells of HNECs. In summary, we developed a nanobody that could effectively inhibit inflammatory signaling in HNECs via intranasal administration, showing promise as a non-invasive rhinitis treatment.