Laboratório de Matriz Extracelular e Biotecnologia de Venenos, Universidade Federal do Paraná, UFPR, Curitiba 81531-980, Brazil.
Laboratório de Toxinologia de Venenos Animais, Fundação Ezequiel Dias, FUNED, Belo Horizonte 30510-010, Brazil.
Toxins (Basel). 2024 Nov 9;16(11):486. doi: 10.3390/toxins16110486.
Viperid snake venoms are notably abundant in metalloproteinases (proteins) (SVMPs), which are primarily responsible for inducing hemorrhage and disrupting the hemostatic process and tissue integrity in envenomed victims. In this study, barnettlysin-III (Bar-III), a hemorrhagic P-III SVMP, was purified from the venom of the Peruvian snake . Bar-III has a molecular mass of approximately 50 kDa and is a glycosylation-dependent functional metalloproteinase. Some biochemical properties of Bar-III, including the full amino acid sequence deduced from its cDNA, are reported. Its enzymatic activity is increased by Ca ions and inhibited by an excess of Zn. Synthetic metalloproteinase inhibitors and EDTA also inhibit its proteolytic action. Bar-III degrades several plasma and ECM proteins, including fibrin(ogen), fibronectin, laminin, and nidogen. Platelets play a key role in hemostasis and thrombosis and in other biological process, such as inflammation and immunity, and platelet activation is driven by the platelet signaling receptors, glycoprotein (GP)Ib-IX-V, which binds vWF, and GPVI, which binds collagen. Moreover, Bar-III inhibits vWF- and convulxin-induced platelet aggregation in human washed platelets by cleaving the recombinant A1 domain of vWF and GPVI into a soluble ectodomain fraction of ~55 kDa (sGPVI). Bar-III does not reduce the viability of cultured endothelial cells; however, it interferes with the adhesion of these cells to fibronectin, vitronectin, and RGD peptides, as well as their migration profile. Bar-III binds specifically to the surface of these cells, and part of this interaction involves α5β1 integrin receptors. These results contribute to a better comprehension of the pathophysiology of snakebite accidents/incidents and could be used as a tool to explore novel and safer anti-venom therapeutics.
蝰蛇毒液富含金属蛋白酶（SVMPs），SVMPs 主要负责诱导出血，破坏中毒受害者的止血过程和组织完整性。在这项研究中，从秘鲁毒蛇毒液中纯化出一种出血性 P-III SVMP，即巴雷特利辛-III（Bar-III）。Bar-III 的分子量约为 50kDa，是一种依赖糖基化的功能金属蛋白酶。报告了其一些生化特性，包括从 cDNA 推导的完整氨基酸序列。其酶活性受 Ca 离子增加和 Zn 过量抑制。合成金属蛋白酶抑制剂和 EDTA 也抑制其蛋白水解作用。Bar-III 降解几种血浆和 ECM 蛋白，包括纤维蛋白原、纤维连接蛋白、层粘连蛋白和巢蛋白。血小板在止血和血栓形成以及其他生物学过程中发挥关键作用，如炎症和免疫，血小板激活由血小板信号受体糖蛋白（GP）Ib-IX-V 驱动，该受体结合 vWF，GPVI 结合胶原。此外，Bar-III 通过切割 vWF 和 convulxin 诱导的血小板聚集中的重组 A1 结构域，将其转化为可溶性 55kDa （sGPVI）的外显子片段，抑制人洗涤血小板中 vWF 和 convulxin 诱导的血小板聚集。Bar-III 不会降低培养的内皮细胞的活力；然而，它会干扰这些细胞与纤维连接蛋白、 vitronectin 和 RGD 肽的黏附以及它们的迁移模式。Bar-III 特异性结合这些细胞的表面，部分相互作用涉及 α5β1 整合素受体。这些结果有助于更好地理解蛇咬伤事故/事件的病理生理学，并可作为探索新型和更安全抗蛇毒治疗的工具。
