CAREER: Small Molecule-Mediated Axonal Regeneration

得克萨斯大学奥斯汀分校的Dionicio Siegel教授将凭借生命过程化学项目颁发的这一职业奖，研究通过使用小分子促进轴突再生的新方法。利用PI实验室合成的一系列天然产物和类似物，并证明它们在体外和体内都具有促进生长和再生的活性，将研究导致再生的分子事件。由于确定小分子作用模式的挑战，研究人员将使用各种不同的方法来识别靶标，包括共价加合物的形成(光亲和亲电诱饵)和药物亲和反应靶标的稳定性。这些研究将与基于APEX质谱学的定量蛋白质组分析相结合进行。对作用模式(S)的确定将为如何利用小分子控制轴突生长发育提供洞察。第二个专注于轴突再生的项目将开发天然产物黄黄素和长黄酮的实验室制剂。这两种化合物都强烈抑制轴突再生的抑制剂信号素3A。黄褐素已经在成年大鼠身上进行了体内研究，并导致了完全脊髓横断后显着的再生。然而，由于缺乏实验室制剂，促进对黄褐素生物学效应的了解的研究有限。该小组将测试一种拟议的非酶二聚序列，该序列在发酵或分离过程中产生化合物。这些合成的完成将为未来专注于优化化合物生物学性能的研究提供一个平台。Siegel教授的大一研究课程“生物勘探：从内生菌中分离出具有生物活性的天然产品”让学生接触到植物学、民族植物学、真菌学、药理学和有机化学的独特组合，从而广泛接触到多个科学领域。此外，这项研究与研究小组对再生的关注是一致的，通过这门课准备的提取物在Siegel实验室基于线虫的神经元生长分析中进行了筛选。该课程利用研究小组的独特能力、现有的合作以及伯德夫人约翰逊野花中心的自然温室设施。由西格尔博士设计，旨在鼓励学生追求化学科学领域的职业。“德克萨斯萨满”是一项为第一题高中生提供参与真正研究的难得机会的项目。为了将目前在科学界代表性不足的学生包括在内，德克萨斯州萨满专门针对来自低收入家庭的学生，这些家庭的大量集中是第一章指定的标准。在过去三年里，在德克萨斯州本土植物中研究天然产品的计划已经在十个试点研讨会上成功实施，并正在扩大到包括更多奥斯汀地区的学校，并为学生进入德克萨斯大学奥斯汀分校的研究实验室提供渠道。

With this CAREER Award from the Chemistry of Life Processes Program Professor Dionicio Siegel of the University of Texas at Austin will examine new ways to promote axonal regeneration through the use of small molecules. With a set of natural products and analogs that the PI's laboratory has synthesized and demonstrated to possess growth promoting and regenerative activities, both in vitro and in vivo, the molecular events leading to regeneration will be investigated. Due to the challenges of determining the modes of action of small molecules the researchers will use a variety of different methods for target identification including covalent adduct formation (photo-affinity and electrophilic baits) and drug affinity responsive target stability.  These studies will be conducted in combination with APEX mass spectroscopy-based quantitative proteomic analyses. The determination of the mode(s) of action will provide insight into how to control axonal growth and development using small molecules. A second project focused on axonal regeneration will develop laboratory preparations of the natural products xanthofulvin and vinaxanthone.  Both compounds strongly inhibit the inhibitor of axonal regeneration, semaphorin3A.  Xanthofulvin has been studied in vivo in adult rats and leads to remarkable regeneration following complete spinal cord transection. The lack of a laboratory preparation, however, has limited studies to advance the understanding of xanthofulvin's biological effects. The group will test a proposed non-enzymatic dimerization sequence that generates the compounds during fermentation or isolation. The completion of the syntheses will provide a platform for future studies focused on optimizing the biological performance of the compounds.Professor Siegel's freshman research class "Bioprospecting: Isolation of Biologically Active Natural Products from Endophytes" exposes students to a unique combination of botany, ethnobotany, mycology, pharmacology, and organic chemistry providing broad exposure to multiple scientific areas.  In addition, the research is in line with the research group's focus in regeneration and the extracts prepared through this class are screened in the Siegel lab's C. elegans-based neuronal outgrowth assays.  The class utilizes the unique capabilities of the research group, existing collaborations, and the nature conservatory facilities at the Lady Bird Johnson Wildflower Center. Designed by Dr. Siegel to encourage pursuit of careers in the chemical sciences "Texas Shamans" is a program that offers Title I high school students the rare opportunity to participate in genuine research. Seeking to include those currently underrepresented in the sciences, Texas Shamans is aimed specifically at students from low-income families, large concentrations of which are the criterion for Title I designation.  The program studying natural products in native Texas plants has been successfully implemented in ten pilot workshops over the past three years and is being expanded to encompass more Austin area schools and provide a conduit for the placement of students into the research labs of University of Texas at Austin.