Disrupting TSLP - TSLP receptor interactions via small molecule inhibitors yields a novel and efficient treatment option for atopic diseases

Thymic stromal lymphopoietin (TSLP) is a key player in the pathogenesis of atopic diseases. Its pathophysiological relevance has sparked great interest in therapeutically targeting TSLP. Yet, so far, no small-mo lecule TSLP inhibitors exist due to the challenging nature of disrupting the protein-protein interaction between TSLP and its receptor. Here, we report the development of small-molecule TSLP receptor inhibitors using structure- based virtual screening and docking of >1,000,000 compounds followed by iterative chemical synthesis. BP79 emerged as our lead compound that effectively abrogates TSLP-triggered cytokine release at low micromolar concentrations. Topical application of BP79 yields efficient skin absorption followed by significant downregulation of atopy-relevant proinflammatory cytokines in immunocompetent skin disease models. For further analysis, we developed a human atopic disease drug discovery platform using microfluidic multi-organ chips. Here, topical application of BP79 onto atopic-like skin disease models that were co -cultivated with lung models in the presence of Th2 cells effectively suppressed immune cell infiltration and key atopy mediators including IL-13, IL-4, TSLP, and periostin, while upregulating skin barrier prote ins such as filaggrin. RNA-Seq analysis corroborated these findings and also indicated protective downstream effects on the lung epithelium. To the best of our knowledge, this represents the first report of a po tent and safe small molecule TSLPR inhibitor which has the potential to expand the therapeutic and preventive options in atopic diseases. Further, it serves as a starting point for further developments in target ing TSLP as a central player of inflammation.