Discerning Specific Thrombolytic Activities and Blood Clot Degradomes of Diverse Snake Venoms with Untargeted Peptidomics.

Many snake venoms have been shown to possess thrombolytic activity. However, it remains unclear if actions on other clot-stabilizing proteins beyond fibrin chains contribute significantly to venom-induced thrombolysis because the clot-wide targets of venom proteases and the mechanisms responsible for thrombolysis are not well understood. Here, we utilize a high-throughput time-based thrombolysis assay in combination with untargeted peptidomics to provide comprehensive insight into the effects of venom from five snake species on blood clot degradation. We compare thrombolytic profiles across venoms with variable levels of proteases and generate venom-specific fingerprints of cleavage specificity. We also compare the specific effects of venoms that possess a range of thrombolytic activity on fibrin chains and other clot-bound proteins involved in clot structure. Protease-rich venom more effectively degraded blood clots. Venoms with higher thrombolytic activity demonstrated an enhanced ability to target multiple sites across fibrin chains critical to clot stability and structure, as well as clot-stabilizing proteins including factor XIII, fibronectin, and vitronectin. Collectively, this study significantly expands our understanding of the thrombolytic and fibrinolytic effects of snake venom by determining the full suite of clot-specific venom targets that are involved in clot formation and stability. This has important implications for the treatment of snake envenomation, the bioprospecting of therapeutically useful molecules, and the development of research tools for investigating hematologic disorders.