Ornella Rossetto

• Biological Sciences
• University of Padua

Background and Purpose Local inhibitory circuits and long‐range inhibitory projections within the interconnected basal ganglia nuclei are critical for control of voluntary movement and pathophysiology of different extrapyramidal movement disorders. Herein, we examined the major motor effects of tetanus neurotoxin (TeNT), a presynaptic neurotoxin se...

The neuromuscular junction (NMJ) plays a key role in modulating muscle contraction, but the impact of short‐term disuse on NMJ structure and function, particularly in older humans, remains unclear. This study aimed to investigate NMJ alterations following 10 days of horizontal bed rest in 10 older males (68.5 ± 2.6 years). Before and after bed rest...

Vascular graft vasospasm is a lethal risk when using grafts for revascularization and reconstructive surgery. Revascularization is a treatment modality for ischemic diseases including Moyamoya disease that requires bypass surgery. Cerebrovascular graft transplantation carries a 5-10% risk of vasospasm, which can lead to devastating neurological seq...

Botulism is a life-threatening disease characterized by a descending flaccid paralysis caused by a protein neurotoxin (BoNT) released by different anaerobic bacterial species of the genus Clostridium. The paralysis results from blockade of neurotransmitter release from the terminals of peripheral cholinergic, skeletal and autonomic neurons exerted...

Background and Purpose Botulinum neurotoxin type A1 (BoNT/A) is one of the most potent neurotoxins known. At the same time, it is also one of the safest therapeutic agents used for the treatment of several human disorders and in aesthetic medicine. Notwithstanding great effectiveness, strategies to accelerate the onset and prolong BoNT/A action wou...

Background and Purpose Botulinum Neurotoxin type A1 (BoNT/A) is one of the most potent neurotoxins known. At the same time, it is also one of the safest therapeutic agents used for the treatment of several human disorders and in aesthetic medicine. Notwithstanding great effectiveness, strategies to accelerate the onset and prolong BoNT/A action wou...

Joensuu and colleagues have recently shown that botulinum neurotoxin (BoNT) type A exploits a heterotrimeric complex in the presynaptic membrane to bind to and enter neurons using a Trojan horse-like mechanism. Similar processes may be relevant to the neuronal entry of different botulinum toxin serotypes and other neuropathogens.

Cephalic tetanus (CT) is a severe form of tetanus that follows head wounds and the intoxication of cranial nerves by tetanus neurotoxin (TeNT). Hallmarks of CT are cerebral palsy, which anticipates the typical spastic paralysis of tetanus, and rapid evolution of cardiorespiratory deficit even without generalized tetanus. How TeNT causes this unexpe...

Tetanus and botulinum neurotoxins cause the neuroparalytic syndromes of tetanus and botulism, respectively, by delivering inside different types of neurons, metalloproteases specifically cleaving the SNARE proteins that are essential for the release of neurotransmitters. Research on their mechanism of action is intensively carried out in order to d...

Tetanus and Botulinum type B neurotoxins are bacterial metalloproteases that specifically cleave the vesicle-associated membrane protein VAMP at an identical peptide bond, resulting in inhibition of neuroexocytosis. The minute amounts of these neurotoxins commonly used in experimental animals are not detectable, nor is detection of their VAMP subst...

We used α-Latrotoxin (α-LTx), the main neurotoxic component of the black widow spider venom, which causes degeneration of the neuromuscular junction (NMJ) followed by a rapid and complete regeneration, as a molecular tool to identify by RNA transcriptomics factors contributing to the structural and functional recovery of the NMJ. We found that Uroc...

Tetanus neurotoxin (TeNT) is a protein exotoxin produced by Clostridium tetani that causes the deadly spastic neuroparalysis of tetanus. It consists of a metalloprotease light chain and of a heavy chain linked via a disulphide bond. TeNT binds to the neuromuscular junction (NMJ) and it is retro-axonally transported into vesicular compartments to th...

Botulinum neurotoxins (BoNTs) produced by soil bacterium Clostridium botulinum are cause of botulism and listed as biohazard agents, thus rapid screening assays are needed for taking the correct countermeasures in a timely fashion. The gold standard method relies on the mouse lethality assay with a lengthy analysis time, i.e., 2-5 days, hindering t...

Tetanus is a deadly but preventable disease caused by a protein neurotoxin produced by Clostridium tetani. Spores of C. tetani may contaminate a necrotic wound and germinate into a vegetative bacterium that releases a toxin, termed tetanus neurotoxin (TeNT). TeNT enters the general circulation, binds to peripheral motor neurons and sensory neurons,...

Botulinum neurotoxins (BoNTs) are a growing family of bacterial protein toxins that cause a generalized flaccid paralysis of botulism by inactivating neurotransmitter release at peripheral nerve terminals. They are the most potent toxins known thanks to the marvel of their protein design, which underlines their mechanism of action. Their unique bio...

Eubacterium tarantellae was originally cultivated from the brain of fish affected by twirling movements. Here, we present the draft genome sequence of E. tarantellae DSM 3997, which consists of 3,982,316 bp. Most protein-coding genes in this strain are similar to genes of Clostridium bacteria, supporting the renaming of E. tarantellae as Clostridiu...

Botulinum neurotoxins (BoNTs) are a growing family of bacterial protein toxins that cause botulism, a rare but often fatal animal and human disease. They are the most potent toxins known owing to their molecular architecture, which underlies their mechanism of action. BoNTs target peripheral nerve terminals by a unique mode of binding and enter int...

The Botulinum NeuroToxin (BoNT) comprises several serotypes with distinct properties, mechanisms of action, sensitivity and duration of effect in different species. The serotype A (BoNT/A) is the prevalent neurotoxin applied in human's disease. In this paper we present an overview of the current knowledge regarding the duration of effect and the ne...

Tetanus and botulinum neurotoxins are the most poisonous substances known, so much so as to be considered for a possible terrorist use. At the same time, botulinum neurotoxin type A1 is successfully used to treat a variety of human syndromes characterized by hyperactive cholinergic nerve terminals. The extreme toxicity of these neurotoxins is due t...

A large number of bacterial toxins consist of active and cell binding protomers linked by an inter‐chain disulfide bridge. The largest family of such disulfide bridged exotoxins is that of the Clostridial neurotoxins that consist of two chains and comprise the tetanus neurotoxins (TeNT) causing tetanus and the botulinum neurotoxins (BoNT) causing b...

Botulinum neurotoxin Type A (BoNT/A) is an effective treatment for several movement disorders, including spasticity and dystonia. BoNT/A acts by cleaving synaptosomal-associated protein of 25 kDa (SNAP-25) at the neuromuscular junction, thus blocking synaptic transmission and weakening overactive muscles. However, not all the therapeutic benefits o...

Botulinum neurotoxin serotypes A and B are successfully used to treat a variety of human diseases characterized by hyperactive peripheral nerve terminals. However, a number of patients are primary resistant to these pharmaceuticals, without having antitoxin‐neutralizing antibodies. A straightforward explanation of this phenomenon posits that mutati...

Medically relevant cases of snakebite in Europe are predominately caused by European vipers of the genus Vipera. Systemic envenoming by European vipers can cause severe pathology in humans and different clinical manifestations are associated with different members of this genus. The most representative vipers in Europe are V. aspis and V. berus and...

Cambridge Core - Neurology and Clinical Neuroscience - Treatment of Dystonia - edited by Dirk Dressler

Tetanus and botulinum neurotoxins are clostridial toxins that cause tetanus and botulism, respectively. Tetanus neurotoxin binds specifically to peripheral motoneuron nerve terminals at the neuromuscular junction and is endocytosed within vesicles, which transport the toxin retroaxonally to the spinal cord. Here, it enters the inhibitory interneuro...

Botulinum neurotoxins are produced by neurotoxigenic spore-forming Clostridia in several dozens of variants that cause a generalized flaccid paralysis of botulism by inactivating neurotransmitter release at peripheral nerve terminals. Botulinum neurotoxins are a marvel of protein design whose unique biological properties have led them to become not...

The Genome Aggregation Database presently contains >120,000 human genomes. We searched in this database for the presence of mutations at the sites of tetanus (TeNT) and botulinum neurotoxins (BoNTs) cleavages of the three SNARE proteins: VAMP, SNAP-25 and Syntaxin. These mutations could account for some of the BoNT/A resistant patients. At the same...

Botulinum (BoNTs) and tetanus (TeNT) neurotoxins are the most toxic substances known and form the growing family of Clostridial neurotoxins (CNT), the etiologic agents of botulism and tetanus. CNT are composed of a metalloprotease light chain (L), linked via a disulfide bond to a heavy chain (H). H mediates the binding to nerve terminals and the me...

Botulinum neurotoxin serotype C (BoNT/C) is a neuroparalytic toxin associated with outbreaks of animal botulism, particularly in birds, and is the only BoNT known to cleave two different SNARE proteins, SNAP-25 and syntaxin. BoNT/C was shown to be a good substitute for BoNT/A1 in human dystonia therapy because of its long lasting effects and absenc...

The cleavage of SNAP-25 by BoNT/C mutants in CGNs does not increase by prolonging the incubation time to 24 hours. CGNs were treated as in Fig 1 but incubation was prolonged to 24 hours. The cleavage of syntaxin-1A/1B and SNAP-25 was assayed by western blot using two antibodies recognizing both the intact and the cleaved forms of the proteins. (TIF...

BoNT/C mutants display a different cytotoxic effect on cultured neurons. CGNs were treated as in Fig 2 but incubation was prolonged to 24 hours. Neurons were then fixed and stained with an antibody against cleaved SNAP-25 (SNAP-25c, in red) and neurofilament-200 (NF200, in green). Cytotoxicity was evaluated following the appearance of varicosities...

SDS-PAGE analysis of the different BoNT/C toxins used in the study. From left to right, 250 nanograms of either native BoNT/C-wt, or recombinant BoNT/C-wt, BoNT/C α-51 or BoNT/C α-3W were loaded in a 12% gel under reducing conditions and revealed by Coomassie staining. The extent of hydrolytic activation of full-length BoNT/C by E. coli proteases w...

Mutations conferring to BoNT/C specificity for syntaxins. Space-filling representation of BoNT/C LC (PDB entry 2QN0) with highlighted triple mutations for syntaxin selectivity [32]: S51T/R52N/N53P (BoNT/C α-51) in green and L200W/M221W/I226W (BoNT/C 0078-3W) in red. Blue spot shows the metalloprotease active site. (TIF)

SNAP-25 cleaved by BoNT/C is recognized by an antibody raised against SNAP-25 cleaved by BoNT/A1. CGNs were treated with BoNT/A1 (0.1 nM) or BoNT/C-wt (0.1 nM) in normal culture medium at 37°C for 3 hours. Thereafter cells were fixed and stained with an antibody raised against SNAP-25 segment 185–197 (red) [37], corresponding to the C-terminus gene...

The study of botulinum neurotoxins (BoNT) is rapidly progressing in many aspects. Novel BoNTs are being discovered owing to next generation sequencing, but their biologic and pharmacological properties remain largely unknown. The molecular structure of the large protein complexes that the toxin forms with accessory proteins, which are included in s...

Introduction: Botulinum neurotoxins (BoNTs) are the most potent toxins known. BoNTs are responsible for botulism, a deadly neuroparalytic syndrome caused by the inactivation of neurotransmitter release at peripheral nerve terminals. Thanks to their specificity and potency, BoNTs are both considered potential bio-weapons and therapeutics of choice...

Scorpions are among the oldest venomous living organisms and the family Buthidae is the largest and most medically relevant one. Scorpion venoms include many toxic peptides, but recently, a metalloprotease from Tityus serrulatus called antarease was reported to be capable of cleaving VAMP2, a protein involved in the neuroparalytic syndromes of teta...

Botulinum neurotoxins are diverse proteins. They are currently represented by at least seven serotypes and more than 40 subtypes. New clostridial strains that produce novel neurotoxin variants are being identified with increasing frequency, which presents challenges when organizing the nomenclature surrounding these neurotoxins. Worldwide, research...

Tetanus and botulinum neurotoxins are clostridial toxins that cause tetanus and botulism, respectively. Tetanus neurotoxin binds specifically to peripheral motoneuron nerve terminals at the neuromuscular junction and is endocytosed within vesicles, which transport the toxin retroaxonally to the spinal cord. Here, it enters the inhibitory interneuro...

Botulinum and tetanus neurotoxins are the most toxic substances known and form the growing family of clostridial neurotoxins (CNTs). They are composed of a metalloprotease light chain (L), linked via a disulfide bond to a heavy chain (H). H mediates the binding to nerve terminals and the membrane translocation of L into the cytosol where their subs...

Botulinum neurotoxins (BoNTs) form a large class of potent and deadly neurotoxins. Given their growing number, it is of paramount importance to discover novel inhibitors targeting common steps of their intoxication process. Recently, EGA was shown to inhibit the action of bacterial toxins and viruses exhibiting a pH-dependent translocation step in...

Tetanus and botulinum neurotoxins are produced by anaerobic bacteria of the genus Clostridium and are the most poisonous toxins known, with 50% mouse lethal dose comprised within the range 0.1 - few nanograms per Kg, depending on the individual toxin. Botulinum neurotoxins are similarly toxic to humans and can therefore be considered for potential...

Epilepsy is characterized by impaired circuit function and a propensity for spontaneous seizures, but how plastic rearrangements within the epileptic focus trigger cortical dysfunction and hyperexcitability is only partly understood. Here we have examined alterations in sensory processing and the underlying biochemical and neuroanatomical changes i...

Botulinum neurotoxins are produced by anaerobic spore-forming bacteria of the genus Clostridium in several dozens of variants that inactivate neurotransmitter release owing to their metalloprotease activity. This results in a persistent paralysis of peripheral nerve terminals known as botulism. They are the most potent toxins known and are classifi...

Botulinum neurotoxins (BoNTs) are Janus toxins, as they are at the same time the most deadly substances known and one of the safest drugs used in human therapy. They specifically block neurotransmission at peripheral nerves through the proteolysis of SNARE proteins, i.e. the essential proteins, which are the core of the neuroexocytosis machinery. E...

Toxins are compounds of different chemical nature, which include cytotoxic proteins, polypeptides of variable lengths, and alkaloids. These molecules are produced by a variety of different organisms and are poisonous to animals. Over the last two decades, our understanding of the mechanism of action of biological toxins has increased enormously. Th...

Background Botulinum toxin A (Onabot/A) has been shown to have an antinociceptive effect. This might be due to an impairment of sensory nerves not only in the peripheral but also in the central nervous system. In this work, we analysed both systems by studying the effect of intrathecal (i.t.) administration of botulinum toxin A in an animal model o...

Botulinum neurotoxins consist of a metalloprotease linked via a conserved interchain disulfide bond to a heavy chain responsible for neurospecific binding and translocation of the enzymatic domain in the nerve terminal cytosol. The metalloprotease activity is enabled upon disulfide reduction and causes neuroparalysis by cleaving the SNARE proteins....

Botulinum neurotoxins (BoNTs) are produced by anaerobic bacteria of the genus Clostridium and cause a persistent paralysis of peripheral nerve terminals, which is known as botulism. Neurotoxigenic clostridia belong to six phylogenetically distinct groups and produce more than 40 different BoNT types, which inactivate neurotransmitter release owing...

Unlike most classical analgesics, botulinum toxin type A (BoNT/A) does not alter acute nociceptive thresholds, and shows selectivity primarily for allodynic and hyperalgesic responses in certain pain conditions. We hypothesized that this phenomenon might be explained by characterizing the sensory neurons targeted by BoNT/A in CNS after its axonal t...

Context: Some clinical aspects about neurotoxicity after snakebites by European viper species remain to be elucidated. Objective: This observational case series aims to analyze neurological manifestations due to viper envenomation in Italy in order to describe the characteristic of neurotoxicity and to evaluate the clinical response to the antid...

The third edition of the Handbook of Proteolytic Enzymes aims to be a comprehensive reference work for the enzymes that cleave proteins and peptides, and contains over 850 chapters. Each chapter is organized into sections describing the name and history, activity and specificity, structural chemistry, preparation, biological aspects, and distinguis...

Botulinum neurotoxins translocate their enzymatic domain across vesicular membranes. The molecular triggers of this process are unknown. Here, we tested the possibility that this is elicited by protonation of conserved surface carboxylates. Glutamate-48, glutamate-653 and aspartate-877 were identified as possible candidates and changed into amide....

Botulinum neurotoxin type A (BoNT/A) is the most frequent cause of human botulism and, at the same time, is largely used in human therapy. Some evidence indicates that it enters inside nerve terminals via endocytosis of synaptic vesicles, though this has not been directly proven. The metal-loprotease L chain of the neurotoxin then reaches the cytos...