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聚醚天然产物是已知的一些最有效的非大分子生物制品。灯盏花毒素(PbTxs)和雪卡毒素(CTxs)是已知的仅有的与电压门控钠通道(VGSCs)5位点高亲和力结合的配体。2004年，我们发现了Brevenal，这是第三类聚醚离子通道调节剂，可以中和第5位有毒配体的作用。与短链毒素和雪卡毒素不同，短链毒素和雪卡毒素在纳摩尔至皮摩尔浓度范围内具有毒性，就我们所研究的而言，短链毒素是无毒的。更重要的是，短链毒素是一种拮抗剂，可以否定、减少或阻止短杆菌毒素和雪卡毒素在每个被检查的系统中的影响。受体结合研究表明，Brevenal不直接竞争5位点，而是非竞争性地调节PBTX活性。生物测试表明，短杆菌对短杆菌毒素和雪卡毒素的体内毒性作用具有拮抗作用。在绵羊吸入模型中，百草枯可阻断PBTX诱导的支气管收缩，并导致气管粘液速度增加。实验结果支持对治疗神经毒性贝类中毒(由短杆菌毒素引起的NSP)和雪卡特鱼中毒(由雪卡毒素引起的CFP)，或更广泛地用于治疗哮喘、慢性阻塞性肺病或囊性纤维化的影响。简而言之，短链杆菌是一个值得研究的分子类。这项建议的主要目标是生产半合成的短链配体，a)表现出更高的亲和力(10 NM)并保持短链受体的受体选择性，最终使这种新型受体的分离和鉴定成为可能，以及b)评估人工合成的短链配体在VITO模型中对短链毒素和雪卡毒素的影响表现出更好的疗效。本研究的最终目标是确定具有潜在用途的聚醚芳香烃衍生物，用于治疗离子通道介导的疾病，特别是针对NSP和CFP，以及那些自然发生的人类疾病，如哮喘、COPD和囊性纤维化，这些疾病已证明存在离子通道调节/功能障碍。以此类推，短链受体位点将因此而变得更加完整，为治疗配体的开发提供了一个新的药物位点。用pdfFactory试用版创建的PDF www.pdffactory.com 与公共卫生相关：摄取或吸入海洋聚醚化合物、短杆菌毒素或雪卡毒素可导致呼吸困难和长期的神经疾病，目前尚无已知的治疗或治愈方法。Bvenal是从海洋甲藻Karenia Brevis中提取的一种天然产品，已被证明可以阻止短杆菌毒素和雪卡毒素的影响。合成高效的芳香烃衍生物可能会导致化合物具有治疗环境神经毒素暴露的潜力，并有助于确定治疗哮喘、囊性纤维化和慢性阻塞性肺病等肺部疾病的新药物位点。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