Molecular mechanisms of botulinum neurotoxin neutralization

肉毒杆菌神经毒素中和的分子机制

基本信息

批准号：
9160875
负责人：
Rongsheng Jin
金额：
$ 63.62万
依托单位：
UNIVERSITY OF CALIFORNIA-IRVINE
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-05-10 至 2021-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9160875
关键词：
Affinity Animals Antidotes Antitoxins Bacterial Toxins Binding Binding Sites Bontoxilysin Botulinum Toxin Type A Botulism Cell surface Centers for Disease Control and Prevention (U.S.)Cleaved cell Clostridium botulinum Communities Complement Complex Data Development Diagnostic Disease Endopeptidases Enteral Epitopes Exposure to Gene Therapy Agent Goals Health Human Immune Sera Infection Infectious Agent Intoxication Invaded Knowledge Lead Length Link Lung Maps Mediating Membrane Methods Microbe Modeling Molecular Mutation Neurons Paralysed Pathology Peptide Hydrolases Peptides Prevention approach Prevention strategy Process Property Proteins Reagent Research Risk Role SNAP receptor Serotyping Serum Severities Site Specificity Structural Models Structure Symptoms Syndrome Technology Testing Therapeutic Time Toxic effect Toxin Virus base biodefense biothreat design flexibility gene therapy improved inhibitor/antagonist innovation interest mouse model neurotoxin receptor neurotransmission novel novel strategies pathogen prevent public health relevance receptor receptor binding small molecule treatment strategy

项目摘要

Project summary Botulism is caused by exposure to protein toxins called botulinum neurotoxins (BoNTs) that are produced by Clostridium botulinum. BoNTs are CDC Tier 1 select agent for which no antidote currently exists. Seven different BoNT serotypes have been discovered to date (BoNT/A-G), many having numerous additional BoNT subtypes. However the only currently available treatments are serum based antitoxin products derived from large animals that are only effective if administered soon after BoNT intoxication. The challenge of developing BoNT therapeutics is exacerbated by the fact that the seven known BoNT serotypes are each distinct toxins with distinct receptor specificities and proteases that cleave at distinct sites on SNARE proteins to disrupt nerve transmission. Due to the severity of the risk, the paucity of treatment options, and the complexity of the challenge, novel approaches to the prevention and treatment of BoNT intoxication are clearly needed. We now have extensive evidence in multiple toxin models demonstrating that bispecific VHH-based neutralizing agents (VNAs), consisting of two covalently linked, toxin-neutralizing VHHs, are antitoxins with potencies that often exceed that of current monoclonal and polyclonal antitoxin agents. Furthermore, VNAs offer substantial advantages over serum and mAb antitoxin products as they are economical to produce and highly versatile; offering innovative new prevention and treatment strategies for toxin exposures and infections with toxin-producing pathogens such as gene therapies and direct delivery to enteric and pulmonary sites of challenge. In this proposal, we test the hypothesis that integrating structural and mechanistic information into VNA design will lead to even greater antitoxin efficacy and versatility. The Specific Aims are to (1) determine the crystal structures of selected BoNT-binding VHHs in complex with their target BoNTs; (2) define the mechanisms by which VHHs selected in Aim 1 block BoNT toxicity, and; (3) design and test bispecific VNAs with enhanced antitoxin properties by exploiting structure/function data from Aims 1 and 2. This will be the first comprehensive structural mapping of BoNT neutralizing epitopes, which will be complemented with mechanistic studies of BoNT function and BoNT-host interactions. Furthermore, this study will improve general understanding of how structural and mechanistic information can inform the design of even more effective VNA antitoxin agents and should permit rapid development of commercial antitoxin therapeutics to treat exposures to all BoNT serotypes and other toxin biothreat agents.