title: Inhibition of botulinum neurotoxins interchain disulfide bond reduction prevents the peripheral neuroparalysis of botulism.
abstract: Botulinum neurotoxins (BoNTs) form a growing family of metalloproteases with a unique specificity either for VAMP, SNAP25 or syntaxin. The BoNTs are grouped in seven different serotypes indicated by letters from A to G. These neurotoxins enter the cytosol of nerve terminals via a 100 kDa chain which binds to the presynaptic membrane and assists the translocation of a 50 kDa metalloprotease chain. These two chains are linked by a single disulfide bridge which plays an essential role during the entry of the metalloprotease chain in the cytosol, but thereafter it has to be reduced to free the proteolytic activity. Its reduction is mediated by thioredoxin which is continuously regenerated by its reductase. Here we show that inhibitors of thioredoxin reductase or of thioredoxin prevent the specific proteolysis of VAMP by the four VAMP-specific BoNTs: type B, D, F and G. These compounds are effective not only in primary cultures of neurons, but also in preventing the in vivo mouse limb neuroparalysis. In addition, one of these inhibitors, Ebselen, largely protects mice from the death caused by a systemic injection. Together with recent results obtained with BoNTs specific for SNAP25 and syntaxin, the present data demonstrate the essential role of the thioredoxin-thioredoxin reductase system in reducing the interchain disulfide during the nerve intoxication mechanism of all serotypes. Therefore its inhibitors should be considered for a possible use to prevent botulism and for treating infant botulism.
authors.affiliation: Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Zanetti
authors.affiliation: Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Azarnia Tehran
authors.affiliation: Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy.
authors.forename: Marcon
authors.initials: M
authors.lastname: Pirazzini
authors.affiliation: Institut für Biochemie, OE 4310, Medizinische Hochschule Hannover, 30623 Hannover, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Binz
authors.affiliation: Public Health England, Porton Down, Salisbury, Wiltshire SP4 OJG, UK.
authors.forename: Clifford C
authors.initials: CC
authors.lastname: Shone
authors.affiliation: Histology and Molecular Biology Section, Army Medical and Veterinary Research Center, Via Santo Stefano Rotondo 4, 00184 Rome, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Fillo
authors.affiliation: Histology and Molecular Biology Section, Army Medical and Veterinary Research Center, Via Santo Stefano Rotondo 4, 00184 Rome, Italy.
authors.forename: Florigio
authors.initials: F
authors.lastname: Lista
authors.affiliation: Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy.
authors.forename: Ornella
authors.initials: O
authors.lastname: Rossetto
authors.affiliation: Dipartimento di Scienze Biomediche, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy; Istituto CNR di Neuroscienze, Università di Padova, Via U. Bassi 58/B, 35121 Padova, Italy. Electronic address: cesare.montecucco@gmail.com.
authors.forename: Cesare
authors.initials: C
authors.lastname: Montecucco
mesh_terms: D000818:Animals; D001905:Botulinum Toxins / Q000737:chemistry* / Q000633:toxicity; D001906:Botulism / Q000150:complications*; D002478:Cells, Cultured; D002531:Cerebellum / Q000187:drug effects*; D008297:Male; D051379:Mice; D009474:Neurons / Q000187:drug effects; D010243:Paralysis / Q000139:chemically induced* / Q000517:prevention & control*; D051381:Rats; D013880:Thioredoxin-Disulfide Reductase / Q000037:antagonists & inhibitors; D013879:Thioredoxins / Q000037:antagonists & inhibitors
chemical_list: D013879:Thioredoxins; D013880:Thioredoxin-Disulfide Reductase; D001905:Botulinum Toxins
keywords: Botulinum neurotoxins; Botulism; Curcumin (PubChem CID: 969516); Ebselen; Ebselen (PubChem CID: 3194); Inhibitors; Myricetin (PubChem CID: 5281672); PX12 (PubChem CID: 219104); Peripheral neuroparalysis; Thioredoxin system