Biochemical and biological characterization of a dermonecrotic metalloproteinase isolated fromCerastes cerastessnake venom

Synergistic Effect of Proteinase Activity by Purification and Identification of Toxic Protease From Nemopilema nomurai

Scyphozoan Nemopilema nomurai envenomation is an unresolved threat to human health in Asian waters. Nemopilema nomurai venom metalloproteinases show important toxicities in skin damage and inflammation, but there is still no purified protein for further studies. In this study, high proteinase activity fractions in tentacle autolysis were isolated by ammonium sulfate precipitation, DEAE Sepharose Fast Flow, and Superdex 75 chromatography successively. Purification was guided by azocasein hydrolysis activity and SDS-PAGE. The final products were analyzed by LC-MS/MS. Four elution peaks purified by Superdex 75 chromatography had multiple protein bands but did not show proteinase activity. These fractions would recover proteinase activity after mixing again. Regulation mechanisms were speculated as binding metalloproteinase regulator or disaggregating metalloproteinase inhibitor by LC-MS/MS analysis. For the first time, a synergistic effect in N. nomurai proteinase activity was found in the purification process.

"Computational and Functional Characterization of a Hemorrhagic Metalloproteinase Purified from Cerastes cerastes Venom"

Structural and functional aspects of snake venoms metalloproteinases (SVMPs) have been extensively studied due to their role in envenomation. However, in the detection of certain coagulation disorders these biomolecules have been used and applied for the production of new thrombolytic drugs. CcMP-II, a SVMP-II metalloproteinase with a hemorrhagic activity, isolated from the venom of Cerastes cerastes, its sequence of 472 amino acids was identified. Predicted 3D structure showed an arrangement of CcMP-II into two distinct domains: i) a metalloproteinase domain where the zinc-binding motif is found (HXXGHNLGIDH) in addition to the sequence Cys-Ile-Met (CIM) at the Met-turn and ii) disintegrin-like domain containing RGD motif. CcMP-II inhibits platelet aggregation induced by collagen in a dose-dependent manner with an IC₅₀ value estimated of 0.11 nM. This proteinase inhibits also aggregation of platelet stimulated by collagen even if the metal chelating agents (EDTA and 1, 10-phenontroline) are present suggesting that anti-aggregating effect is not due to its metalloproteinase domain, but to its disintegrin-like domain. Capillary pathological modifications caused by CcMP-II following intramuscular injection have as well been examined in mice. The key morphological alterations of the capillary vessels were clearly apparent from the ultrastructural study. The CcMP-II can play a key function in the pathogenesis of disorders that occurs following envenomation of Cerastes cerastes. The three-dimensional model of CcMP-II was built to explain structure-function relationships in ADAM/ADAMTs, a family of proteins having significant therapeutic potential. In order to explain structure-function relationships in ADAM / ADAMT, a family of proteins with considerable therapeutic potential, the three-dimensional model of CcMP-II was constructed.

Myotoxicity induced by Cerastes cerastes venom: Beneficial effect of heparin in skeletal muscle tissue regeneration

Myonecrosis is a relevant tissue damage induced by snakes of Viperidae family often leading to permanent tissue and function loss and even amputation. The aim of this study was to evaluate the effect of heparin on skeletal muscle tissue regeneration after Cerastes cerastes envenomation. Mice received either the venom (1 LD₅₀) by i.m. route, or the venom followed, by heparin administration by i.v. route at 15 min and 4 h. Obtained results showed that Cerastes cerastes venom induced deep tissue structure alterations, characterized mainly by edema, hemorrhage, myonecrosis and inflammation. Myotoxicity was correlated with increased CK levels in sera, concomitant with their decrease in muscle tissue homogenates. Muscle wet weight was restored within 2 weeks after heparin treatment and 28 days in the envenomed group. Heparin treatment significantly decreased MPO activity, suggesting an anti-inflammatory effect. NO, HGF, VEGF and G-CSF levels were increased after heparin administration. These mitogenic factors constitute potent stimuli for satellite and endothelial cells improving, thus, muscle regeneration. This study showed that muscle tissue recovery was significantly enhanced after heparin treatment. Heparin use seems to be a promising therapeutic approach after viper envenomation.

Protease Activity Profiling of Snake Venoms Using High-Throughput Peptide Screening

Snake venom metalloproteinases (SVMPs) and snake venom serine proteinases (SVSPs) are among the most abundant enzymes in many snake venoms, particularly among viperids. These proteinases are responsible for some of the clinical manifestations classically seen in viperid envenomings, including hemorrhage, necrosis, and coagulopathies. The objective of this study was to investigate the enzymatic activities of these proteins using a high-throughput peptide library to screen for the proteinase targets of the venoms of five viperid (Echis carinatus, Bothrops asper, Daboia russelii, Bitis arietans, Bitis gabonica) and one elapid (Naja nigricollis) species of high medical importance. The proteinase activities of these venoms were each tested against 360 peptide substrates, yielding 2160 activity profiles. A nonlinear regression model that accurately described the observed enzymatic activities was fitted to the experimental data, allowing for the comparison of cleavage rates across species. In this study, previously unknown protein targets of snake venom proteinases were identified, potentially implicating novel human and animal proteins that may be involved in the pathophysiology of viper envenomings. The functional relevance of these targets was further evaluated and discussed. These new findings may contribute to our understanding of the clinical manifestations and underlying biochemical mechanisms of snakebite envenoming by viperid species.