Structure-Based Design and Synthesis of Stapled Panx1 Analogues for Use in Cardiovascular Inflammatory Diseases.

Following a rational design, a series of macrocyclic ("stapled") peptidomimetics of Panx1, the most established peptide inhibitor of Pannexin1 (Panx1) channels, were developed and synthesized. Two macrocyclic analogues and outperformed the linear native peptide. During adenosine triphosphate (ATP) release and Yo-Pro-1 uptake assays in a Panx1-expressing tumor cell line, both compounds were revealed to be promising bidirectional inhibitors of Panx1 channel function, able to induce a two-fold inhibition, as compared to the native Panx1 sequence. The introduction of triazole-based cross-links within the peptide backbones increased helical content and enhanced proteolytic stability in human plasma (>30-fold longer half-lives, compared to Panx1). In adhesion assays, a "double-stapled" peptide, inhibited ATP release from endothelial cells, thereby efficiently reducing THP-1 monocyte adhesion to a TNF-α-activated endothelial monolayer and making it a promising candidate for future investigations in animal models of cardiovascular inflammatory disease.