and X.D. collagen, ADP, and thrombin while demonstrating both antithrombotic and thrombolytic activities26. After further purification, agkisacutacin was later found to bind platelet GPIb as well as coagulation factors IX and X, and inhibit GPIb-VWF dependent ristocetin-induced platelet aggregation27. Thus, although anfibatide and agkisacutacin share the properties of binding to and inhibiting VWF-mediated functions of GPIb, only anfibatide shows unique selectivity for platelet GPIb. At least three additional GPIb-binding snaclecs have been isolated from venom; agkicetin C and akitonin, which inhibit platelet function, and agkaggregin, which induces platelet activation. Flavocetin-A and echicetin, isolated from Habu snake venom, are two snaclecs that also inhibit VWF access to GPIb; however, they can both support and inhibit platelet aggregation23,24,29,31. Akitonin and jararaca GPIb-BP, isolated from Bothrops jararaca, are GPIb antagonists that decrease platelet aggregation in vitrobut their in vivo efficacy and bleeding AZD8931 (Sapitinib) diathesis have not been reported32,33. We previously evaluated properties of purified anfibatide in vitro and in vivowith mouse models of thrombogenesis21. We showed that anfibatide specifically inhibits the GPIb-VWF AZD8931 (Sapitinib) conversation as well as platelet functions known to depend on it, including ferric chloride- and laser-induced thrombus formation in mesenteric and cremaster muscle mass arterioles21,34. Such findings suggest that anfibatide has the potential of acting as a GPIb selective antithrombotic agent in humans, as we briefly reported in 2013 annual meeting of American Society of Hematology35. Since the GPIb-VWF conversation is usually purely required for thrombogenesis at pathological levels of shear stress, anfibatide may offer an improved risk/benefit ratio compared to IIb3 and VWF antagonists36, particularly in the management and treatment of acute coronary syndromes in which acute occlusion entails pathologically elevated shear stress. Since then, anfibatide has been shown as a encouraging candidate that could be beneficial for the treatment of ischemic stroke and has a protective effect on cerebral ischemia/reperfusion injury in animal models37C40. Also, when anfibatide is usually administered at the optimal dosage, route, and interval, it is effective in treating spontaneous and bacterial shigatoxin-induced TTP in murine models. These studies may provide the basis for further development of anfibatide for the treatment of acute TTP in humans41. In addition, the first balanced expression strain and pilot-scale production of recombinant anfibatide in has been reported42,43, aiming to solve the quality control troubles of purifying anfibatide from natural snake venom and the limited supply of this natural resource. Further improvements of recombinant anfibatide are still under development. This present study evaluates the antithrombotic efficacy and security of anfibatide in vitrovenom Anfibatide was purified from your snake venom (produced by Huangshan Huizhou Research Institute of Snake Venom, Huangshan, China) by anion-exchange chromatography and cation-exchange chromatography followed by immuno-affinity chromatography with a specific anti-anfibatide monoclonal antibody 1B9 (produced by Zhaoke Pharmaceutical Co. Ltd., Hefei, China)43. The eluted product was further purified by size exclusion chromatography using a Sephacryl S-100 column. After the four-step purification (Supplementary Methods), MALDI-TOF mass spectrometry analysis showed a single peak, indicative of high purity, with a mass to charge ratio (m/z) of 29,799.7 (Fig.?1A), which corresponds to the theoretical molecular excess weight of anfibatide of approximately 30?kDa. This single-peak protein was Rabbit Polyclonal to USP6NL utilized for subsequent in vitro and ex lover AZD8931 (Sapitinib) vivo experiments as well as for the phase I clinical trial. Open in a separate windows Physique 1 Purification and structure of anfibatide with GPIb. (A) MALDI-TOF mass spectrometry showed a mass to charge ratio (m/z) of 29,799.7. Three-dimensional models of (B) structure of anfibatide (purple) integrated with GPIb (orange) and (C) VWF-A1 domain name (green) and GPIb complex from PDB access 1SQ045 (https://www.rcsb.org/structure/1SQ0). (D) -Thrombin (blue) and GPIb complex from PDB access 1OOkay44 (https://www.rcsb.org/structure/1OOK). Red arrows point to the sulfotyrosine region of GPIb, the -thrombin AZD8931 (Sapitinib) binding site. Protein-complex AZD8931 (Sapitinib) figures generated using Schrodinger PyMol 2 software (https://pymol.org/2/). In silico modeling of the anfibatideCGPIb conversation We have reported the crystal structure of anfibatide24. To elucidate the potential binding site of anfibatide on GPIb, a three-dimensional structural model of the GPIb-anfibatide complex was generated by in silico molecular docking based.