A therapeutic for Lyme disease based on Peptidoglycan Recognition Protein 1

摘要 莱姆病是北美最常见的媒介传播疾病，由伯氏螺旋体引起。感染始于被感染的扁虱叮咬后的皮肤，急性疾病的特征是头痛、发烧和肌肉痛。目前，还没有针对莱姆病的人类疫苗，治疗性给予抗生素仍然是推荐的治疗方案。如果没有被扁虱叮咬的记忆，或者如果早期症状没有被注意到和没有得到治疗，螺旋体可以传播到皮肤、心脏、神经系统和关节的远端，导致播散性莱姆病的临床表现，包括心脏炎、神经疏螺旋体病和关节炎。早期和晚期播散性莱姆病的治疗选择也是口服抗生素14-21天或更长时间，或静脉注射抗生素。在北美，60%未经治疗的莱姆病患者会患上莱姆关节炎，其中高达10%的患者即使在长期接受抗生素治疗后也会出现滑膜炎。长期抗生素治疗的不良事件，以及对宿主微生物群对健康重要性的日益认识，强调需要开发有效的替代治疗方案来控制莱姆病。为了实现这一目标，这项提案将确定肽聚糖识别蛋白1(PYGLRP1)在莱姆病小鼠模型中控制伯氏疏螺旋体感染的效用。 利用表达1000多种人类免疫受体和分泌蛋白的酵母展示文库，我们研究了人类免疫受体与伯氏杆菌之间的分子相互作用，结果表明绝大多数伯氏杆菌菌株严格与PGLYRP1特异结合。体外实验表明，PGLYRP1具有杀灭螺旋体的活性。我们推测，PGLYRP1是一种肽聚糖识别蛋白，可能被宿主用来识别和根除伯氏杆菌。与我们的假设一致，缺乏PGLYRP1的小鼠的伯氏杆菌负担比对照小鼠增加。因此，在本提案的目标1中，我们将评估重组PGLYRP1作为一种治疗手段在莱姆病小鼠模型中根除伯氏杆菌感染的潜力。在这项研究的目标2中，我们将确定PGLYRP1是否与头孢曲松等β-内酰胺类抗生素协同作用以预防伯氏杆菌感染。这项研究的结果将为未来的努力提供基础，以确定PGLYRP1的最佳配方，作为莱姆病的治疗药物。

ABSTRACT Lyme disease, the most common vector-borne illness in North America, is caused by the spirochete B. burgdorferi. Infection begins in the skin following an infected tick-bite and acute illness is characterized by headache, fever and myalgia. Currently, there is no human vaccine against Lyme disease and therapeutic administration of antibiotics remains the recommended treatment option. In the absence of a recollection of a tick bite, or if the early symptoms go unnoticed and untreated the spirochete can disseminate to distal regions of the skin, heart, nervous system and the joints, leading to clinical manifestations of disseminated Lyme disease including carditis, neuroborreliosis and arthritis. The treatment option for early and late disseminated Lyme disease is also oral antibiotic treatment for 14-21 days or longer, or intravenous antibiotic administration. In North America, 60 % of untreated Lyme disease patients develop Lyme arthritis and up to 10 % of these patients demonstrate synovitis even after prolonged antibiotic treatment. Adverse events from prolonged antibiotic treatment, and the growing understanding of the importance of the host microbiome in health, emphasize the need to develop effective alternative treatment options for the control of Lyme disease. Towards this goal, this proposal will determine the utility of Peptidoglycan Recognition Protein 1 (PYGLRP1) to control Borrelia burgdorferi infection in a murine model of Lyme disease. Using a yeast display library expressing over 1000 human immune receptors and secretory proteins we examined molecular interactions between human immune receptors and B. burgdorferi and showed that a vast majority of strains of B. burgdorferi sensu stricto bind specifically to PGLYRP1. In-vitro experiments demonstrated that PGLYRP1 has borreliacidal activity. We hypothesize that PGLYRP1, a peptidoglycan-recognition protein, may be used by the host to recognize and eradicate B. burgdorferi. Consistent with our hypothesis, B. burgdorferi burden in mice lacking PGLYRP1 was increased compared to that in control mice. Therefore, in Aim 1 of this proposal, we will evaluate the potential of recombinant PGLYRP1 as a therapeutic to eradicate B. burgdorferi infection in a murine model of Lyme disease. In Aim 2 of this study we will determine whether PGLYRP1 acts synergistically with beta-lactam antibiotics such as ceftriaxone to prophylactically treat B. burgdorferi infection. The results of this study will provide the basis for future efforts that will define an optimal formulation of PGLYRP1 as a therapeutic for Lyme disease.