Mechanistic investigation of bacterial type 9 secretion system machinery and its involvement in gut metabolism and immunomodulation

9型细菌分泌系统机制及其参与肠道代谢和免疫调节的机制研究

• 批准号: 10667632
• 负责人: Abhishek Shrivastava
• 金额: $ 39.25万
• 依托单位: ARIZONA STATE UNIVERSITY-TEMPE CAMPUS
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2027-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10667632
• 关键词: Animals; Bacteroides; Bacteroidetes; Biochemistry; Bioinformatics; Biological Models; Caspase; Chlorobi; Collection; Data; Dietary Fiber; Enzymes; Extracellular Protein; Fermentation; Future; Genetic; Gram-Negative Bacteria; Health; Health Benefit; Human; Immune; Investigation; Knowledge; Metabolic Diseases; Metabolism; Microbe; Motor; Oligosaccharides; Pectate lyase; Prevotella; Production; Property; Protein Export Pathway; Protein Secretion; Proteins; Research Design; Resources; Role; Sensory; Shapes; Structure; System; Testing; Transportation; Volatile Fatty Acids; biophysical model; cell motility; experimental study; gut microbes; gut microbiota; immunoregulation; microbial community; model organism; mouse model; oral microbial community; pathogen

SUMMARY Metabolites generated by the gut microbiota provide multiple health benefits. However, the mechanism via which the gut microbiota utilizes substrates from the host and generates beneficial products are not well understood. Additionally, information regarding the role of secretome i.e., a collection of extracellular proteins secreted by the gut microbiota on health is minimal. Currently, no model system for the study of Type 9 protein Secretion System (T9SS) of gut microbes exists. Our preliminary bioinformatics analysis suggests the presence of functional T9SS in several human gut isolates of the genus Bacteroides. We predict that the T9SS of gut Bacteroides secretes pectate lyase and other enzymes that breakdown dietary fibers and subsequently ferment them to short- chain fatty acids (SCFAs). Reduction of SCFAs results in metabolic disorders. We predict that the relatively understudied, yet important, human gut isolates that include Bacteroides intestinalis, Bacteroides nordii, Bacteroides fluxus, Prevotella copri, and Parabacteroides distasonsis secrete many proteins via T9SS. We are developing a genetically tractable species B. intestinalis as a model organism to fill knowledge gap regarding studies of T9SS secretome in the gut. We hypothesize that the T9SS secretome of the gut microbiota might create a common pool of oligosaccharides that enrich SCFA producing species. Additionally, we aim to find controllers of a putative Bacteroides sensory transduction network that senses the abundance of dietary fibers and regulates production of SCFA producing enzymes. Our preliminary data also predicts the secretion of immune-suppressive cysteine proteases by the T9SS of B. intestinalis. The proposed experiments to test our predictions and hypothesis will significantly enhance our understanding of interspecies cooperation, resource optimization, and immunomodulation by the gut microbiota. T9SS is a recently discovered protein export pathway of bacteria of the Gram-negative Fibrobacteres-Chlorobi-Bacteroidetes superphylum. Thus far, the model organisms for the study of T9SS are from the human oral microbiota, environmental isolates, and pathogens infecting aquatic animals. With this proposal, we are using our expertise with T9SS to push the barriers that impede our understanding of secretome of the gut microbiota. The nuts and bolts of T9SS machinery are composed of nineteen different proteins but their structure and functional properties are unclear. In future, this information can help us control T9SS of the gut microbiota. At the core of T9SS is a rotary motor that powers gliding motility of microbes. This motility enables cargo transportation and shapes the spatial organization of a microbial community. We propose experiments to fill the gap regarding the mechanism via which T9SS enables bacterial motility and protein secretion. Two important knowledge gaps: (a) the role of T9SS in the gut microbiota, and (b) the structure and function of T9SS will be filled via a multi- pronged experimental approach that uses genetics, biochemistry, biophysics, and murine models. Together, we aim to gain a mechanistic understanding of T9SS machinery, its secretome in the gut microbiota, and their impact on health.

概括 肠道菌群产生的代谢产物可提供多种健康益处。但是， 肠道菌群利用宿主底物并产生有益的机制 产品不太了解。此外，有关秘密作用的信息，即 肠道微生物群在健康方面分泌的细胞外蛋白质的收集很少。 目前，没有用于研究肠道微生物9型蛋白质分泌系统（T9SS）的模型系统 存在。我们的初步生物信息学分析表明，在几种中存在功能性T9S 人类肠道菌属的肠道分离株。我们预测肠道菌核的T9SS分泌 凝固裂解酶和其他酶，这些酶破坏饮食纤维，然后将其发酵为短 链脂肪酸（SCFA）。 SCFA的减少会导致代谢疾病。我们预测 相对研究，但重要但重要的是人类肠道分离株，包括杀菌剂肠道， 细菌型Nordii，细菌Fluxus，Prevotella copri和副细胞动物的蒸馏器分泌许多 蛋白质通过T9SS。我们正在开发一种遗传牵引性物种B.肠道作为模型生物 填补有关肠道中T9SS分泌的研究的知识差距。我们假设T9SS 肠道菌群的分泌组可能会产生一个富含SCFA的寡糖的常见池 生产物种。此外，我们旨在查找推定的菌落感觉转导的控制器 感知丰富饮食纤维并调节SCFA产生的网络 酶。我们的初步数据还可以预测免疫抑制半胱氨酸蛋白酶的分泌 肠道芽孢杆菌的T9SS。提出的测试我们预测和假设的实验将 显着增强我们对种间合作，资源优化和 肠道菌群免疫调节。 T9SS是最近发现的革兰氏阴性细菌的蛋白质输出途径 纤维杆菌 - 氯杆菌 - 杆菌素超细胞。到目前为止，用于研究T9SS的模型生物 来自人类口腔微生物群，环境分离株和感染水生动物的病原体。 有了这项建议，我们正在利用T9SS的专业知识来推动阻碍我们的障碍 了解肠道菌群的分泌组。 T9SS机械的螺母和螺栓是组成的 在19种不同的蛋白质中，但它们的结构和功能特性尚不清楚。将来，这个 信息可以帮助我们控制肠道菌群的T9S。 T9SS的核心是旋转电机 动力滑行微生物。这种运动能够使货物运输并塑造空间 微生物社区的组织。我们提出了实验以填补有关机制的空白 通过该T9SS可以实现细菌运动和蛋白质分泌。两个重要的知识差距：（a） T9S在肠道菌群中的作用，（b）T9SS的结构和功能将通过多种 使用遗传学，生物化学，生物物理学和鼠模型的实验方法。 我们共同旨在获得对T9SS机械的机械理解，这是肠道中的秘密 微生物群及其对健康的影响。