Neurotoxins from Marine Algae and Cyanobacteria

描述(申请人提供)：天然产物因其对特定生化途径和受体的有效和选择性靶向而在神经药理学中发挥着关键作用，并作为探针物质和治疗线索非常有用。海洋蓝藻富含各种天然产物结构，其中许多是有毒的或具有其他生物学特性。我们建议继续我们一位天然产品化学家(Gerwick)和一位神经药理学家(Murray)之间的富有成效的合作，扩大我们之前对这些生命形式的研究，寻找它们新的和具有生物洞察力的神经活性化合物。因此，我们的长期目标是1)开发新的化合物作为药理学和细胞生物学的新工具，2)描述新的假定的环境毒素，以便在发生疫情时采取适当的行动，以及3)开发神经活性物质作为潜在的治疗先导化合物，特别是在治疗中风引起的脑损伤方面。为了实现这些目标，我们有以下四个具体目标：1)收集250个蓝藻和藻类的样本，并产生高质量的集中组分文库，用于检测神经活性天然产物的分析；2)利用大脑皮层神经元的高通量自发钙振荡和Na+内流分析来评估上述各种提取物；3)使用创新和加速的方法从海洋蓝藻中分离新的神经活性物质，并对其结构进行表征；4)以纳米级核磁共振和MSN方法为特色，进一步确定在先前支持过程中发现的几种蓝藻毒素的分子药理学。此外，评估新发现的蓝藻配体对新皮质神经元的轴突生长、棘突形成和突触形成的影响。在这些体外试验中，选定的活性化合物将被推进到局灶性中风的小鼠模型中。这将需要生产更多的供应品或这些新发现的化合物的类似物，包括用于放射性配体结合和分布分析的放射性同位素标记的类似物。完成这些目标将增加我们对海洋蓝藻和藻类产生的独特和具有神经活性的天然产物的了解。过去两个周期对这一协作计划的支持卓有成效，我们现在拥有了一个成熟、运作良好和高效的计划。我们继续改进应用于新型海洋神经活性物质的发现和应用的方法和思路，这将引领我们为拟议的未来资助期提供新的研究方向，例如将促进新皮质神经元突起生长的电压门控钠通道激动剂应用于卒中所致脑损伤的潜在治疗。

DESCRIPTION (provided by applicant): Natural products have played pivotal roles in neuropharmacology due to their potent and selective targeting of specific biochemical pathways and receptors, and are highly useful as probe substances and therapeutic leads. Marine cyanobacteria are exceptionally rich in diverse natural product structures, many of which are toxic or have other biological properties. We propose to continue our productive collaboration between a natural products chemist (Gerwick) and a neuropharmacologist (Murray), expanding on our previous investigations of these life forms for their new and biologically-insightful neuroactive compounds. Thus, we have the long range goals of 1) developing new compounds to serve as novel tools for pharmacology and cell biology, 2) describing new putative environmental toxins so that appropriate actions can be taken should outbreaks occur, and 3) development of neuroactive substances as potential therapeutic lead compounds, especially in the treatment of stroke-induced brain injury. To accomplish these goals we have the following four specific aims: 1) to collect 250 samples of cyanobacteria and algae, and produce high quality focused fraction libraries for screening in assays designed to detect neuroactive natural products, 2) to evaluate the above diverse extracts using high throughput spontaneous Ca2+ oscillation and Na+ influx assays in cerebrocortical neurons, 3) to use innovative and accelerated methods to isolate and structurally characterize new neuroactive substances from marine cyanobacteria testing positively in the screening assays, featuring nanoscale NMR and MSn methods, 4) to further define the molecular pharmacology of several cyanobacterial toxins discovered during prior support. Additionally, to evaluate the influence of newly discovered cyanobacterial ligands on neurite outgrowth, spinogenesis and synaptogenesis in neocortical neurons. Select compounds active in these in vitro assays will be advanced into a mouse model for focal stroke. This will require the production of additional supplies or analogs of these newly discovered compounds, including radioisotope-labeled analogs to be used in radioligand binding and distribution assays. Completion of these aims will increase our knowledge of the unique and neuroactive natural products produced by marine cyanobacteria and algae. The past two cycles of support for this collaborative program have been highly productive, and we now have a mature, well functioning, and highly effective program. We continue to refine our approaches and thinking as applied to the discovery and utility of novel marine neuroactive substances, and this leads us in new research directions for the proposed coming grant period, such as the application of voltage-gated sodium channel activators that promote neurite outgrowth in neocortical neurons to the potential treatment of stroke-induced brain injury.