Dissecting bacteriophage:treponeme interactions to develop novel therapeutics for bovine digital dermatitis

摘要：牛数字性皮炎（BDD）是一种由严重足部病变引起的传染性跛行。这种疾病非常痛苦，对经济和粮食安全有相当大的影响，包括减少产奶量和繁殖，仅英国每年就损失7400万英镑。密螺旋体被认为是BDD的致病因子，利物浦大学（UoL）负责分离/鉴定了大量分离物（180+）。在BBSRC RM的资助下，我们完成了BDD密螺旋体基因组和蛋白质组，并确定了生存/发病机制(1)。尽管迄今为止只有一种噬菌体被表征为密螺旋体，但我们已经确定了在密螺旋体物种中存在溶原噬菌体的证据（未发表的基因组/电镜分析）。此外，一系列假定的毒素：抗毒素（TA）系统在BDD三螺旋体中编码(1)，TA系统被认为是噬菌体防御机制。鉴于目前还没有全面的BDD治疗方法，本项目将识别和表征螺旋体噬菌体，因为它们代表了潜在的治疗/控制剂。该项目为BBSRC DTP博士研究生，具体目标如下：目的：从利物浦大学（UoL）培养收集的密螺旋体中分离溶原噬菌体，并从反刍动物足拭子和农场泥浆中分离专性溶原噬菌体。我们将对分离的噬菌体进行基因组测序和鉴定，并研究它们的特异性。开展噬菌体-宿主协同进化实验，剖析菌种特异性的噬菌体机制。表征螺旋体毒素对噬菌体的抑制作用：抗毒素（TA）系统。开发能够靶向BDD中涉及的各种螺旋体物种的溶解噬菌体鸡尾酒。上述研究将大大促进对噬菌体：螺旋体相互作用的理解，并产生有利于牛健康的新治疗方法。参考文献：1)剖析牛和人密螺旋体的分子多样性和共性，确定关键的生存和粘附机制。PLoS Pathog. 2021 Mar 29;17(3):e1009464。doi: 10.1371 / journal.ppat.1009464。

Summary:Bovine digital dermatitis (BDD) is an infectious lameness in dairy cattle worldwide caused by severe foot lesions. The disease is extremely painful and has considerable economic and food security implications including reduced milk yield and reproduction, costing the UK alone £74 Million/year. Treponemes are considered BDD causal agents and the University of Liverpool (UoL) has been responsible for isolation/characterisation of a large panel of isolates (180+). With BBSRC RM funding we completed BDD treponeme genomes and proteomes and identified survival/pathogenesis mechanisms(1). Despite only a single bacteriophage to date being characterised for Treponema, we have identified evidence of lysogenic phage in treponemal species (unpublished genomic/electron microscope analyses). Furthermore, a range of putative toxin:antitoxin (TA) systems are encoded within BDD treponemes(1), with TA systems recognised as bacteriophage defence mechanisms. Given no comprehensive BDD treatment exists, this project will identify and characterise treponeme bacteriophage given they represent potential therapeutic/control agents. The project is a BBSRC DTP PhD studentship with specific objectives as follows:1. To isolate lysogenic bacteriophage from treponemes within the University of Liverpool (UoL) culture collection and to isolate obligately lytic phage from ruminant foot swabs and farm slurry. We will genome sequence and characterise isolated bacteriophage, as well as investigating their specificity.2. To undertake bacteriophage-host co-evolution experiments to dissect bacteriophage mechanisms of bacterial species specificity.3. To characterise phage inhibition by treponeme toxin:antitoxin (TA) systems.4. To develop cocktails of lytic bacteriophage capable of targeting the diverse range of treponemal species involved in BDD.The above described study should substantially further the understanding of bacteriophage:spirochete interaction as well as resulting in novel treatments beneficial for cattle health. References:1) Dissecting the molecular diversity and commonality of bovine and human treponemes identifies key survival and adhesion mechanisms. PLoS Pathog. 2021 Mar 29;17(3):e1009464. doi:10.1371/journal.ppat.1009464.