Snake Venom Cytotoxins, Phospholipase A2s, and Zn2+-dependent Metalloproteinases: Mechanisms of Action and Pharmacological Relevance

Snake venom toxins are responsible for causing severe pathology and toxicity following envenomation including necrosis, apoptosis, neurotoxicity, myotoxicity, cardiotoxicity, profuse hemorrhage, and disruption of blood homeostasis. Clinically, snake venom toxins therefore represent a significant hazard to snakebite victims which underscores the need to produce more efficient anti-venom. Some snake venom toxins, however, have great potential as drugs for treating human diseases. In this review, we discuss the biochemistry, structure/function, and pathology induced by snake venom toxins on human tissue. We provide a broad overview of cobra venom cytotoxins, catalytically active and inactive phospholipase A₂s (PLA₂s), and Zn²⁺-dependent metalloproteinases. We also propose biomedical applications whereby snake venom toxins can be employed for treating human diseases. Cobra venom cytotoxins, for example, may be utilized as anti-cancer agents since they are efficient at destroying certain types of cancer cells including leukemia. Additionally, increasing our understanding of the molecular mechanism(s) by which snake venom PLA₂s promote hydrolysis of cell membrane phospholipids can give insight into the underlying biomedical implications for treating autoimmune disorders that are caused by dysregulated endogenous PLA₂ activity. Lastly, we provide an exhaustive overview of snake venom Zn²⁺-dependent metalloproteinases and suggest ways by which these enzymes can be engineered for treating deep vein thrombosis and neurodegenerative disorders.