Tapping into an anthelmintic Bacillus thuringiensis crystal protein arsenal for human strongyloidiasis

利用苏云金芽孢杆菌晶体蛋白库治疗人类类圆线虫病

• 批准号: 10088404
• 负责人: RAFFI V AROIAN
• 金额: $ 20.64万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-25 至 2022-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10088404
• 关键词: Abdominal Pain; Accounting; Address; Adult; Albendazole; Alcohol abuse; Amino Acid Sequence; Amino Acids; Animal Model; Animals; Anorexia; Anthelmintics; Ascaris; Bacillus thuringiensis; Bacteria; Biological; Caenorhabditis elegans; Characteristics; Child; Chronic; Colitis; Constipation; Crystallization; Development; Diarrhea; Disease Vectors; Dose; Drug resistance; Engineering; FDA approved; Fatality rate; Female; Food; Formulation; Frequencies; Future; Gastrointestinal tract structure; Generations; Gerbils; Goals; Grant; Growth; HTLV-1 Infection; Helminthiasis; Hemorrhage; Hookworms; Human; Immunocompromised Host; Immunosuppressive Agents; In Vitro; Infection; Information Dissemination; Ingestion; Insecta; Insecticides; Intestinal Obstruction; Intestines; Invertebrates; Ivermectin; Larva; Lead; Lung diseases; Modeling; Mosquito Control; Nature; Nematoda; Nematode infections; Organ; Parasite resistance; Parasites; Parasitic nematode; Peritoneum; Pharmaceutical Preparations; Prevalence; Proteins; Pruritus; Resistance; Sepsis; Simuliidae; Small Intestines; Soil; Strongyloides; Strongyloides stercoralis; Strongyloidiasis; Symptoms; Testing; Tissues; Transgenic Organisms; Urticaria; Variant; Vertebrates; Veterinary Medicine; Work; World Health Organization; alcohol abuse therapy; alternative treatment; chronic infection; clinical development; combat; combinatorial; drug discovery; in vivo; in vivo evaluation; lung injury; neglect; neglected tropical diseases; nonhuman primate; novel therapeutics; programs; screening; virtual

Project Summary/Abstract Human strongyloidiasis is considered the most neglected of the neglected tropical diseases caused primarily by the intestinal parasitic nematode Strongyloides stercoralis, infecting an estimated 300 million people. Chronic infections with S. stercoralis cause abdominal pain, anorexia, diarrhea constipation, urticaria, and itching and are associated with growth stunting in children. Its larvae can also autoinfect the human host, resulting in many generations of autoinfection. In immunosuppressed patients autoinfection can become unregulated, resulting hyperinfection and in severe intensification of symptoms. Hyperinfections may disseminate to organs and tissues causing severe bleeding, small bowel obstruction and colitis, severe pulmonary disease and sepsis, with fatality rates are as high as 80%. Currently we have only one main drug to treat all parasitic stages of S. stercoralis, ivermectin. However, ivermectin resistance in Strongyloides and other intestinal parasitic nematodes is already present, and in some cases rampant, especially in veterinary medicine. Drugs with new modes of action against this deadly parasite are urgently needed. The soil-bacterium Bacillus thuringiensis (Bt) is the number one biological insecticide agent in the world. The insect-active components are crystal (Cry) proteins that kill insects but that are harmless to vertebrates (no effect >1000 mg/kg). Insecticidal Bt Cry proteins are expressed in transgenic food crops (e.g., >80% of USA corn) and are FDA approved for ingestion. The nematode-active Cry protein, Cry5B (related to insecticidal Cry proteins), cures hookworm and Ascaris intestinal nematode infections in large animals and has been studied extensively. More recently, other parasitic nematode-active Cry proteins have been identified, including Cry14A and Cry21A. These are highly effective in vitro against free-living S. stercoralis adults at low doses, raising the possibility that they may represent a new cure for this parasite. This proposal aims to take advantage of 22 known natural amino acid variants of both proteins to find the optimal Cry14A and Cry21A sequences that target this parasite, screening against both free-living adult and parasitic female stages. Once identified, the best Cry14A and Cry21A protein variants will be tested for their ability to cure S. stercoralis infections in vivo in gerbils. The interaction of these proteins with ivermectin-resistant nematodes and, conversely, the interaction of ivermectin with Cry14A resistant nematodes will be investigated. Future plans include dose ranging studies, optimum formulation, detailed engineering and sequence optimization for efficacy and protein yield, studies of mechanism of action and resistance, testing in higher models including natural S. stercoralis infections in non-human primates, and combinatorial studies with ivermectin and other Cry proteins. At the end, we expect to have identified the first new lead anthelmintic against S. stercoralis approval of ivermectin in 1988.

项目总结/摘要 人类类圆线虫病被认为是最被忽视的热带病， 肠道寄生线虫粪类圆线虫（Strongyloides stercoralis），估计感染了3亿人。 慢性感染S.粪属引起腹痛、厌食、腹泻、便秘、荨麻疹， 瘙痒，并与儿童生长发育迟缓有关。它的幼虫也能自动感染人类宿主， 导致许多代的自身感染。在免疫抑制的患者中，自身感染可成为 不受控制，导致过度感染和症状严重加剧。过度感染可能 扩散到器官和组织，引起严重出血、小肠梗阻和结肠炎、严重肺 疾病和败血症，病死率高达80%。目前，我们只有一种主要药物来治疗所有 寄生期S.粪菌、伊维菌素。然而，类圆线虫和其他线虫对伊维菌素的耐药性 肠道寄生线虫已经存在，并且在某些情况下猖獗，特别是在兽医学中。 迫切需要具有新作用模式的药物来对抗这种致命的寄生虫。土壤杆菌 苏云金杆菌（Bt）是世界上第一大生物杀虫剂。昆虫活性成分是 晶体（Cry）蛋白质，杀死昆虫，但对脊椎动物无害（无影响>1000 mg/kg）。杀虫 Bt Cry蛋白在转基因粮食作物中表达（例如，>80%的美国玉米），并获得FDA批准， 摄入具有线虫活性的Cry蛋白Cry 5 B（与杀虫Cry蛋白有关）可治愈钩虫， 蛔虫肠道线虫感染大型动物，并已被广泛研究。最近，其他 寄生线虫活性Cry蛋白已被鉴定，包括Cry 14 A和Cry 21 A。这些都是高度 在体外对自由生活的S.在低剂量下，Stercoralis成年人，提高了他们可能 代表了治疗这种寄生虫的新方法该提案旨在利用22种已知的天然氨基酸 这两种蛋白质的变体，以找到靶向这种寄生虫的最佳Cry 14 A和Cry 21 A序列，筛选 对自由生活的成年和寄生的女性阶段。一旦鉴定，最好的Cry 14 A和Cry 21 A蛋白 将测试变体治愈S的能力。沙鼠体内粪菌感染。这些因素的相互作用 蛋白质与伊维菌素抗性线虫的相互作用，相反，伊维菌素与Cry 14 A的相互作用 将研究抗性线虫。未来的计划包括剂量范围研究，最佳配方， 针对功效和蛋白质产量的详细工程设计和序列优化，作用机制研究 和阻力，测试更高的模型，包括自然S。非人灵长类动物中的粪菌感染，以及 伊维菌素和其他Cry蛋白的组合研究。最后，我们希望能确定第一个 新的驱蠕虫先导药物。1988年，Stercoralis批准了伊维菌素。