Development of High Affinity Analogues of Brevenal: Novel Molecular Probes for Ne

描述（由申请人提供）：由海洋甲藻产生的反式-顺式海洋聚醚天然产物是已知的一些最有效的非大分子生物制剂。Brevetoxins（PbTxs）和ciguatoxins（CTX）是已知以高亲和力结合电压门控钠通道（VGSC）上的位点5的唯一配体。2004年，我们发现了Brevenal，第三类聚醚离子通道调节剂，可抵消位点5毒性配体的作用。与在纳摩尔至皮摩尔浓度范围内有毒的短尾蛇毒和雪卡毒素不同，据我们调查，短尾蛇毒是无毒的。更重要的是，brevenal是一种拮抗剂，可以在每个检查的系统中消除，减少或防止短尾蛇毒素和雪卡毒素的影响。受体结合研究表明，Brevenal不直接竞争位点5，但非竞争性调节PbTx活性。生物学试验表明，Brevenal在体内可拮抗短毒素和雪卡毒素的毒性作用。在绵羊吸入模型中，Brevenal阻断PbTx诱导的支气管收缩并导致气管粘液流速增加。通过实验结果支持了对神经毒性贝类中毒（由于短吻贝毒素的NSP）和雪卡毒素鱼中毒（由于雪卡毒素的CFP）的治疗，或更广泛地用于治疗哮喘、COPD或囊性纤维化的意义。总之，Brevenal是一个值得研究的分子类别。该提议的关键目标是产生半合成的短尾醛衍生物，其a）表现出对短尾醛受体的增加的亲和力（<10 nM）和受体选择性的保留，最终使得能够分离和表征这种新型受体，和B）评估合成产生的衍生短尾醛配体，其在体外模型中表现出针对短尾毒素和雪卡毒素的作用的改善的功效。本研究的最终目标是鉴定具有用于治疗离子通道介导的疾病的潜力的聚醚Brevenal衍生物，具体针对NSP和CFP，以及用于那些自然发生的人类疾病，如哮喘、COPD和囊性纤维化，对于这些疾病，存在已证实的离子通道介导/功能障碍。通过类推，由于本申请的结果，将变得更充分表征的brevenal受体位点为治疗性配体开发提供了新的药物位点。使用pdfFactory试用版创建的PDF www.pdffactory.com 公共卫生相关性：摄入或吸入海洋聚醚化合物、短尾藻毒素或雪卡毒素可导致呼吸困难和长期神经系统疾病，目前尚无已知的治疗或治愈方法。Brevenal是一种来自海洋甲藻Karenia Brevis的天然产物，已被证明可以阻断短鞭藻毒素和雪卡毒素的作用。高效的Brevenal衍生物的合成可以产生具有治疗暴露于环境神经毒素的潜力的化合物，并有助于鉴定用于治疗肺部疾病如哮喘、囊性纤维化和COPD的新药位点。使用pdfFactory试用版创建的PDF www.pdffactory.com

DESCRIPTION (provided by applicant): The trans-syn class of marine polyether natural products produced by marine dinoflagellates are some of the most potent non-macromolecular biologicals known. Brevetoxins (PbTxs) and ciguatoxins (CTXs) are well known as the only ligands known to bind to site 5 on voltage-gated sodium channels (VGSCs) with high affinity. In 2004, we discovered brevenal, a third class of polyether ion channel modulator which counteracts the effects of site 5 toxic ligands. Unlike brevetoxins and ciguatoxins which are toxic in the nanomolar to picomolar concentration ranges, brevenal is non-toxic as far as we have investigated. More importantly, brevenal is an antagonist which negates, reduces, or prevents the effects of brevetoxin and ciguatoxin in every system examined. Receptor binding studies have demonstrated that brevenal does not directly compete for site 5 but non-competitively regulates PbTx activity. Biological testing showed brevenal to be antagonistic to the toxic effects of brevetoxins and ciguatoxins in vivo. In sheep inhalation models, brevenal blocks PbTx-induced bronchoconstriction and leads to increased tracheal mucous velocity. Implications for treatment of neurotoxic shellfish poisoning (NSP due to brevetoxin) and ciguatera fish poisoning (CFP due to ciguatoxin), or more broadly for the treatment of asthma, COPD or Cystic Fibrosis are supported through experimental results. In short, brevenal is a molecular class worthy of study. Key objectives of this proposal are to produce semi-synthetic brevenal derivatives that a) exhibit increased affinity (<10 nM) and retention of receptor selectivity for the brevenal receptor, ultimately enabling the isolation and characterization of this novel receptor, and b) assess synthetically-produced derivative brevenal ligands which exhibit improved efficacy against the effects of brevetoxin and ciguatoxin in in vito models. The ultimate goal of this research is to identify polyether brevenal derivatives with potential for use in the treatment ion-channel mediated disorders, with specific intent towards NSP and CFP, and for those naturally occurring human maladies like asthma, COPD, and cystic fibrosis, for which there is a demonstrated ion channel mediation/dysfunction. By analogy, the brevenal receptor site which will become more fully characterized as a result of this application provides a new drug locus for therapeutic ligand development. PDF created with pdfFactory trial version www.pdffactory.com PUBLIC HEALTH RELEVANCE: Ingestion or inhalation of the marine polyether compounds, brevetoxins or ciguatoxins, can lead to respiratory difficulty and prolonged neurological disorders for which there is, currently, no known treatment or cure. Brevenal, a natural product derived from the marine dinoflagellate Karenia Brevis has been shown to block effects of brevetoxins and ciguatoxins. Synthesis of highly potent brevenal derivatives could lead to compounds with the potential for treating exposure to environmental neurotoxins and aid in the identification of a new drug locus for treatment of pulmonary disorders such as asthma, cystic fibrosis and COPD. PDF created with pdfFactory trial version www.pdffactory.com