Activating autophagy in filarial worms to identify novel macrofilaricides

激活丝虫中的自噬以鉴定新型大丝虫杀剂

• 批准号: 10040523
• 负责人: Sara Lustigman
• 金额: $ 23.79万
• 依托单位: NEW YORK BLOOD CENTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-19 至 2022-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10040523
• 关键词: Adult; Affect; Age; Albendazole; Anaplasma; Animal Model; Animals; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Area; Autophagocytosis; Bacteria; Blindness; Brugia; Brugia malayi; Cells; Cessation of life; Chemicals; Child; Citrates; Clinical Research; Country; Cytoplasm; Data; Defense Mechanisms; Dermal; Development; Diethylcarbamazine; Dose; Doxycycline; Drug Design; Drug Targeting; Drug resistance; Drug usage; Ehrlichia; Elephantiasis; Embryonic Development; Environment; Eukaryotic Cell; Female; Fertility; Filaria bancrofti; Filarial Elephantiases; Future; Goals; Grant; Human; In Vitro; Infection; Insecta; International; Intestinal Volvulus; Ivermectin; Jird; Libraries; Ligands; Loa loa; Lymphatic System; Modeling; Natural Product Drug; Nematoda; Ocular Onchocerciasis; Onchocerca volvulus; Onchocerciasis; Parasites; Pathology; Pathway interactions; Pharmaceutical Preparations; Phylogenetic Analysis; Play; Pregnant Women; Process; Reproduction; Rickettsia; Role; Subcutaneous Nodule; Symbiosis; Testing; Virus; Visual impairment; Wolbachia; World Health Organization; base; cell motility; disability; endosymbiont; filaria; fitness; high risk; human pathogen; in vitro Assay; in vivo; mutualism; new therapeutic target; novel; novel strategies; pathogen; programs; symbiont; translational approach; transmission process

More than 120 million of poorest in the world are at high risk of suffering the debilitating effects of the parasitic filarial nematodes⎯ Wuchereria bancrofti, Brugia malayi, and B. timori ⎯ that live in the lymphatic system and cause human lymphatic filariasis, commonly known as elephantiasis, as well as other severe pathologies. Onchocerciasis (river blindness), for one, is caused by Onchocerca volvulus, which resides within subcutaneous nodules and releases the microfilariae (Mf) that are responsible for ocular or dermal pathologies, including blindness. International control programs, which target 1.5 billion people in danger of infection, focus on controlling the transmission of infections. Unfortunately, the treatments used for mass drug administration initiatives (ivermectin) produce only microfilaricidal effects – they block transmission but have no effect on the adult parasites. They also require long-term yearly administration, are contraindicated in areas co-endemic with Loa loa, exempt children and pregnant women, and promote drug resistance in filarial nematodes. Together, these limitations point to a crucial need for the development of new anti-filarial drugs, specifically macrofilaricidal drugs that kill adult worms. Recent data demonstrate the unique potential of using Wolbachia, the mutualistic bacteria of filarial nematodes, as a novel chemotherapeutic target against human filarial infections. Clinical studies showed that the administration of antibiotics (doxycycline) kills endosymbionts and causes macrofilaricidal effects. To explore this potential, we introduce a novel approach: a host(parasite)- oriented treatment that induces a host innate defense and forces filarial nematodes to eliminate their endosymbiont. We intend to take advantage of autophagy, a mechanism of eukaryotic cells to maintain a healthy intracellular environment and protect cells against intracellular invaders (e.g., bacteria, virus es). The process is essential for bacteria-filaria symbiosis and its alteration killed Wolbachia and, consequently, the worm itself. We obtained proof, that niclosamide (autophagy inducer) activates autophagy in parasites, significantly decreases number of bacteria and causes embryostatic effect in adult worms. Our project will determine that the autophagy inducers can be candidate macrofilaricidal drugs. In Aim 1, to prove that autophagy inducers are effective in vivo against filarial parasites and can be used as macrofilaricidal drugs, we will evaluate the efficacy of niclosamide in Brugia infected jirds. In parallel, we will test the other 23 repurposed drugs (known autophagy inducers) on adult Brugia parasites in vitro and compare their effects on the Wolbachia load and adult worm fitness. The in vitro assays in Aim 1 will result in the selection of the best hits (even better than niclosamide). In Aim 2, the best 2 candidates will be validated in our in vivo Brugia/jird model of infection. Our end goal is to identify effective new microfilaricides that interfere with symbiosis. This initiative, we believe, will yield a new class of active compounds and open perspectives for repurposed drugs, for use as alternatives to or in combination with current anti-filarial treatments.

世界上超过1.2亿最贫穷的人面临着遭受寄生性丝虫病的高度风险，如班氏吴策线虫、马来丝虫和B。帝汶丝虫生活在淋巴系统中，引起人类淋巴丝虫病，俗称象皮病，以及其他严重的病理。盘尾丝虫病（河盲症）是由盘尾丝虫引起的，盘尾丝虫存在于皮下结节内并释放微丝蚴（Mf），微丝蚴是导致眼部或皮肤病理学的原因，包括失明。针对15亿有感染危险的人的国际控制方案侧重于控制感染的传播。不幸的是，用于大规模药物管理计划（伊维菌素）的治疗只产生杀微丝蚴的效果-它们阻止传播，但对成虫没有影响。它们还需要长期每年给药，在与Loa loa共同流行的地区禁用，儿童和孕妇豁免，并促进丝虫的抗药性。总之，这些局限性表明迫切需要开发新的抗丝虫药物，特别是杀死蠕虫的杀大型丝虫药物。最近的数据表明，使用沃尔巴克氏体，丝虫的互利共生细菌，作为一种新的化疗靶点对人类丝虫感染的独特潜力。临床研究表明，抗生素（强力霉素）的管理杀死内共生菌，并导致巨丝虫的影响。为了探索这种潜力，我们引入了一种新的方法：一种以宿主（寄生虫）为导向的治疗方法，诱导宿主先天防御，迫使丝虫线虫消除它们的内共生体。我们打算利用自噬，真核细胞的一种机制来维持健康的细胞内环境并保护细胞免受细胞内入侵者（例如，细菌、病毒）。这一过程对于细菌-丝虫共生是必不可少的，它的改变杀死了沃尔巴克氏体，从而杀死了蠕虫本身。我们获得了证据，氯硝柳胺（自噬诱导剂）激活寄生虫的自噬，显着减少细菌的数量，并在蠕虫中引起胚胎抑制作用。我们的项目将确定自噬诱导剂可以作为候选的杀微丝蚴药物。在目的1中，为了证明自噬诱导剂在体内有效对抗丝虫寄生虫，并且可以用作杀大型丝虫药物，我们将评估氯硝柳胺在感染丝虫的沙鼠中的功效。与此同时，我们将在体外测试其他23种重新利用的药物（已知的自噬诱导剂）对成虫的影响，并比较它们对沃尔巴克氏体负荷和成虫适应性的影响。目标1中的体外测定将导致选择最佳命中（甚至优于氯硝柳胺）。在目标2中，最佳的2个候选物将在我们的体内Brugia/jird感染模型中验证。我们的最终目标是确定有效的新的微丝蚴干扰共生。我们相信，这一举措将产生一类新的活性化合物，并为重新利用药物开辟前景，作为目前抗丝虫治疗的替代品或与之结合使用。