title: A breakthrough on Amanita phalloides poisoning: an effective antidotal effect by polymyxin B.
abstract: Amanita phalloides is responsible for more than 90 % of mushroom-related fatalities, and no effective antidote is available. α-Amanitin, the main toxin of A. phalloides, inhibits RNA polymerase II (RNAP II), causing hepatic and kidney failure. In silico studies included docking and molecular dynamics simulation coupled to molecular mechanics with generalized Born and surface area method energy decomposition on RNAP II. They were performed with a clinical drug that shares chemical similarities to α-amanitin, polymyxin B. The results show that polymyxin B potentially binds to RNAP II in the same interface of α-amanitin, preventing the toxin from binding to RNAP II. In vivo, the inhibition of the mRNA transcripts elicited by α-amanitin was efficiently reverted by polymyxin B in the kidneys. Moreover, polymyxin B significantly decreased the hepatic and renal α-amanitin-induced injury as seen by the histology and hepatic aminotransferases plasma data. In the survival assay, all animals exposed to α-amanitin died within 5 days, whereas 50 % survived up to 30 days when polymyxin B was administered 4, 8, and 12 h post-α-amanitin. Moreover, a single dose of polymyxin B administered concomitantly with α-amanitin was able to guarantee 100 % survival. Polymyxin B protects RNAP II from inactivation leading to an effective prevention of organ damage and increasing survival in α-amanitin-treated animals. The present use of clinically relevant concentrations of an already human-use-approved drug prompts the use of polymyxin B as an antidote for A. phalloides poisoning in humans.
authors.affiliation: UCIBIO/REQUIMTE-Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua José Viterbo Ferreira no 228, 4050-313, Porto, Portugal. garciaju1987@gmail.com.
authors.forename: Juliana
authors.initials: J
authors.lastname: Garcia
authors.affiliation: UCIBIO/REQUIMTE-Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua José Viterbo Ferreira no 228, 4050-313, Porto, Portugal.
authors.forename: Vera Marisa
authors.initials: VM
authors.lastname: Costa
authors.affiliation: Department of Cell and Molecular Biology, Computational and Systems Biology, Biomedical Center, Uppsala University, Box 596, 751 24, Uppsala, Sweden.
authors.forename: Alexandra T P
authors.initials: AT
authors.lastname: Carvalho
authors.affiliation: School of Health Sciences, Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal.|ICVS/3B's-PT Government Associate Laboratory, Braga, Guimarães, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Silvestre
authors.affiliation: Faculty of Sport, CIAFEL, University of Porto, Porto, Portugal.
authors.forename: José Alberto
authors.initials: JA
authors.lastname: Duarte
authors.affiliation: Department of Cell and Molecular Biology, Computational and Systems Biology, Biomedical Center, Uppsala University, Box 596, 751 24, Uppsala, Sweden.
authors.forename: Daniel F A R
authors.initials: DF
authors.lastname: Dourado
authors.affiliation: UCIBIO/REQUIMTE-Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua José Viterbo Ferreira no 228, 4050-313, Porto, Portugal.
authors.forename: Marcelo D
authors.initials: MD
authors.lastname: Arbo
authors.affiliation: UCIBIO/REQUIMTE-Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua José Viterbo Ferreira no 228, 4050-313, Porto, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Baltazar
authors.affiliation: UCIBIO/REQUIMTE-Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua José Viterbo Ferreira no 228, 4050-313, Porto, Portugal.|Department of Legal Medicine and Forensic Sciences, Faculty of Medicine, University of Porto, Porto, Portugal.|Department of Sciences, IINFACTS-Institute of Research and Advanced Training in Health Sciences and Technologies, Advanced Institute of Health Sciences-North (ISCS-N), CESPU, CRL, Gandra, Portugal.
authors.forename: Ricardo Jorge
authors.initials: RJ
authors.lastname: Dinis-Oliveira
authors.affiliation: CIMO/School of Agriculture, Polytechnic Institute of Bragança, Campus de Santa Apolónia Apartado 1172, 5301-854, Bragança, Portugal.
authors.forename: Paula
authors.initials: P
authors.lastname: Baptista
authors.affiliation: UCIBIO/REQUIMTE-Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua José Viterbo Ferreira no 228, 4050-313, Porto, Portugal.
authors.forename: Maria
authors.initials: M
authors.lastname: de Lourdes Bastos
authors.affiliation: UCIBIO/REQUIMTE-Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua José Viterbo Ferreira no 228, 4050-313, Porto, Portugal. felixdc@ff.up.pt.
authors.forename: Félix
authors.initials: F
authors.lastname: Carvalho
mesh_terms: D053959:Alpha-Amanitin / Q000506:poisoning; D000545:Amanita; D000818:Animals; D000931:Antidotes / Q000008:administration & dosage / Q000494:pharmacology*; D003198:Computer Simulation; D006801:Humans; D017093:Liver Failure / Q000209:etiology / Q000517:prevention & control; D008297:Male; D051379:Mice; D062105:Molecular Docking Simulation; D056004:Molecular Dynamics Simulation; D009145:Mushroom Poisoning / Q000188:drug therapy*; D011112:Polymyxin B / Q000008:administration & dosage / Q000494:pharmacology*; D012319:RNA Polymerase II / Q000037:antagonists & inhibitors; D051437:Renal Insufficiency / Q000209:etiology / Q000517:prevention & control; D015996:Survival Rate; D013997:Time Factors
chemical_list: D053959:Alpha-Amanitin; D000931:Antidotes; D012319:RNA Polymerase II; D011112:Polymyxin B
keywords: Kidney; Liver; Polymyxin B; RNA polymerase II; α-Amanitin