γ-Bungarotoxin impairs the vascular endothelial barrier function by inhibiting integrin α5.

γ-bungarotoxin (γ-BGT) is an RGD motif-containing protein, derived from the venom of Bungarus multicinctus , leading to acute death in mice. These RGD motif-containing proteins from snake venom belonging to the disintegrin family can interfere with vascular endothelial homeostasis by directly binding cell surface integrins. Targeting integrins that generate vascular endothelial dysfunction may contribute to γ-BGT poisoning, however, the underlying mechanisms have not been investigated in detail. In this study, the results showed that γ-BGT played a role in -promoting the permeability of the vascular endothelial barrier. Depending on its selective binding to integrin α5 in vascular endothelium (VE), γ-BGT initiated downstream events, including focal adhesion kinase dephosphorylation and cytoskeleton remodeling, resulting in the intercellular junction interruption. Those alternations facilitated paracellular permeability of VE and barrier dysfunction. Proteomics profiling identified that as a downstream effector of the integrin α5 / FAK signaling pathway cyclin D1 partially mediated the cellular structural changes and barrier dysfunction. Furthermore, VE-released plasminogen activator urokinase and platelet-derived growth factor D could serve as potential diagnostic biomarkers for γ-BGT-induced vascular endothelial dysfunction. Our results indicate the mechanisms through which γ-BGT as a novel disintegrin directly interacts with the VE, with consequences for barrier dysfunction. • γ-BGT increases the permeability of the vascular endothelial barrier. • γ-BGT suppresses integrin α5 and contributes to intercellular junctions and cytoskeleton remodeling. • Integrin α5/FAK/CCND1 pathway is partly involved in γ-BGT-induced barrier disruption. • PLAU and PDGFD could serve as potential diagnostic biomarkers for γ-BGT poisoning [ABSTRACT FROM AUTHOR]