Differential Effects of Marimastat and Prinomastat on the Metalloprotease Activity of Various Snake Venoms

Snakebite envenoming is a neglected tropical disease, responsible for approximately 140,000 deaths globally each year. Vipers and elapid snakes represent the most significant snake families in medical contexts, exhibiting a variety of venom components and clinical effects in bite victims. Metalloproteases, a primary component of venoms, are mainly accountable for haemotoxic and myotoxic effects. Although predominantly found in viper venoms, these enzymes are also present in varying levels in elapid snake venoms. Marimastat and prinomastat are matrix metalloprotease inhibitors initially developed as cancer therapies. Recently, extensive research has focused on these inhibitors to neutralise venom metalloproteases. However, their effects on different viper and elapid snake venoms remain unclear. Here, we report the sensitivity of seven elapid venoms (specifically, cobras) and 12 viper venoms to marimastat and prinomastat, utilising selective in vitro experiments and molecular docking analyses performed using representative metalloprotease (VAP2, a viper metalloprotease from the venom of <i>Crotalus atrox</i> and an elapid metalloprotease from the venom of <i>Naja atra</i>) structures. Both compounds inhibited the metalloprotease, fibrinogenolytic, and caseinolytic activities of most viper venoms. While prinomastat displayed prominent inhibitory effects on cobra venoms in these assays, marimastat demonstrated limited inhibitory effects on these venoms. These findings illustrate the role of matrix metalloprotease inhibitors in modulating metalloprotease activities across a range of viper and cobra venoms. Collectively, this study establishes the differential effects of marimastat and prinomastat on various levels of metalloproteases present in viper and elapid venoms. This will enhance understanding of the abundance of metalloproteases in snake venoms and their sensitivity to different matrix metalloprotease inhibitors.