Endosymbiont mediated chitin catabolism in the tsetse fly gut impacts trypanosome transmission

采采蝇肠道内共生介导的几丁质分解代谢影响锥虫传播

• 批准号: 10572879
• 负责人: BRIAN L WEISS
• 金额: $ 26.37万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-11-07 至 2024-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10572879
• 关键词: African; Animals; Arthropod Vectors; Arthropods; Bacteria; Biological Models; Catabolism; Chitin; Chitinase; Chromosomes; Communities; Culicidae; Data; Development; Disease; Disease Vectors; Environment; Enzymes; Epidemiology; Epithelium; Exhibits; Food; Genes; Genetic; Genome; Geography; Glucosamine; Glycosaminoglycans; Goals; Human; In Vitro; Infection; Ingestion; Interdisciplinary Study; Investigation; Kenya; Knock-out; Knowledge; Laboratories; Learning; Lectin; Leishmania; Mediating; Midgut; Modeling; Movement; Musca domestica; Outcome; Parasites; Pathogenicity; Periodicity; Phlebotominae; Physiological; Physiology; Plasmodium; Population; Prevalence; Process; Production; Proteins; Research; Role; Salivary Glands; Sand Flies; Structure; Symbiosis; Taxonomy; Ticks; Toxin; Trypanocidal Agents; Trypanosoma; Trypanosoma brucei brucei; Tsetse Flies; Vertebral column; Work; density; disorder control; endosymbiont; experimental study; extracellular; fly; inhibitor; insight; migration; mutant; novel; novel strategies; overexpression; particle; pathogen; socioeconomics; success; transmission process; vector; vector competence; vector-borne

The midgut of most arthropods is lined by a peritrophic matrix (PM) that is composed of a chitin backbone upon which assemble a variety of glycosaminoglycans and proteins. The PM serves a defensive role within arthropods by protecting their midgut epithelia from abrasive food particles, regulating the movement of ingested toxins, and serving as a physical barrier against pathogen infection establishment. Some vector-borne protozoan pathogens, including mosquito-transmitted Plasmodium and sand fly-transmitted Leishmania, secrete chitinases that can degrade PM-associated chitin. However, tsetse fly-transmitted African trypanosomes do not produce chitinase, and the mechanism(s) these parasites use to circumvent tsetse’s PM are poorly understood. In addition to potentially being infected with African trypanosomes, all tsetse flies harbor a taxonomically variable community of endosymbiotic bacteria. The success of trypanosome transmission through the tsetse vector depends in part on physiological interactions between the fly and these bacteria. One of tsetse’s endosymbionts, Sodalis glossinidius, exhibits a homogeneous distribution within all laboratory colonized flies and a heterogeneous distribution within and between wild fly populations. Several independent field and laboratory-based studies have repeatedly demonstrated a positive correlation between the presence and density of Sodalis in tsetse’s midgut and the ability of trypanosomes to successfully establish an infection in the fly. The mechanisms that underlie this correlation have never been determined. In this application our interdisciplinary research team will address the hypothesis that a Sodalis secreted endochitinase degrades the chitinous backbone of tsetse’s PM. We speculate that Sodalis-mediated degradation of PM-associated chitin facilitates trypanosome infection establishment in two ways. First, this process would compromise the structural integrity of the PM, thus making it easier for trypanosomes to cross. Second, chitin catabolism results in the production of N-acetyl-D-glucosamine, which is a potent inhibitor of trypanocidal lectins. We propose to use Sodalis mutants that cannot produce endochitinase to functionally characterize the tripartite relationship between the bacterium, tsetse’s PM, and trypanosome infection establishment in the fly’s midgut. Additionally, we propose to use field captured tsetse flies to determine if their Sodalis produce endochitinase that mediates the structural integrity of their tsetse host’s PM. Completion of the experiments proposed in this application will increase our understanding of the basic physiological mechanisms that mediated trypanosome transmission through the tsetse vector and may have translational implications towards the development of novel disease control strategies. Additionally, knowledge obtained herein will be applicable to other arthropod vector model systems (e.g., mosquitoes, ticks, sandflies) that house midgut-associated bacteria and have a PM that pathogens must cross in order to be transmitted to a new vertebrate host.

大多数节肢动物的中肠被腹膜基质（PM）衬里，该基质由几丁质主链组成 组装各种糖胺聚糖和蛋白质。 PM在节肢动物中发挥了防御作用 通过保护其中肠上皮免受磨料颗粒的侵蚀，调节摄入的毒素的运动和 作为病原体感染机构的物理障碍。一些载体传播的原生动物病原体， 包括蚊子传播的质量和沙蝇传递的利什曼尼亚，秘密几丁质酶可以 降解与PM相关的几丁质。但是，采采蝇传输的非洲锥虫不会产生几丁质酶， 这些寄生虫用来绕过采集采集的PM的机制知之甚少。 除了可能被非洲锥虫感染外，所有拍摄的苍蝇在分类学上都具有 内体性细菌的可变社区。锥体传播通过采集的成功 矢量部分取决于苍蝇与这些细菌之间的物理相互作用。采摘者之一 内共生菌，苏达利斯·格洛西尼朱尼斯（Sodalis glossinidius 以及野生蝇种群之间和之间的异质分布。几个独立领域和 基于实验室的研究反复证明存在与密度之间存在正相关 sodalis在TSETSE的中肠和锥虫成功建立感染的能力。 基于这种相关性的机制从未确定。在此应用中，我们的跨学科 研究小组将解决以下假设，即苏达利人分泌的内chitinase降解了有利的。 TSETSE PM的骨干。我们推测，苏达利介导的PM相关丁丁蛋白的降解促进 锥虫感染以两种方式建立。首先，此过程将损害结构完整性 PM的含量，从而使锥虫大体更容易穿越。第二，几丁质分解代谢导致生产 N-乙酰基-D-葡萄糖胺的含量，这是锥虫讲座的潜在抑制剂。我们建议使用Sodalis突变体 不能产生内胆碱酶以在功能上表征细菌之间的三方关系， 采摘的PM和Fly的Midgut中的锥虫感染设施。此外，我们建议使用字段 捕获的采采蝇以确定其sodalis是否产生介导的内切蛋白酶介导的结构完整性 他们的采摘主持人的总理。在本申请中提出的实验的完成将增加我们的 了解通过 采取媒介，可能对新型疾病控制的发展具有翻译意义 策略。此外，此处获得的知识将适用于其他节肢动物矢量模型系统 （例如，蚊子，tick虫，沙叶）容纳了中肠相关细菌，并具有病原体必须的PM 交叉以传输到新的脊椎动物主机。