Host factors influencing early clearance of Streptococcus pneumoniae from the middle ear following invasion from the nasopharynx

项目概要 该提案解决了细菌性中耳炎（OM）这一具有临床意义的问题，这是医院中耳炎的主要来源。 幼儿就诊和可预防的听力损失以及抗生素最常见的诊断 这个年龄段的处方。肺炎链球菌是引起细菌性肺炎的两种最常见原因之一 OM，由细菌从鼻咽部侵入中耳引起。尽管疫苗广泛普及 尽管使用，肺炎链球菌仍然是重要的 OM 病原体，这表明需要新的治疗方法。 然而，对于导致细菌 OM 的宿主因素仍然存在巨大的知识差距。 发病机制。为了解决这些知识空白，我们开发了一种新的肺炎链球菌小鼠模型 侵犯中耳。该模型基于病毒合并感染增加 OM 的临床观察 儿童和小鼠中的风险会促进肺炎链球菌的入侵。我们发现连续施用病毒 dsRNA 类似物 Poly(I:C) 足以促进肺炎链球菌侵入中耳。 Poly(I:C) 诱导 I 型干扰素 (IFN) 的产生，有助于肺炎链球菌在其他组织中的存活。在 第一个目标是，我们提出 I 型干扰素可增强中耳肺炎链球菌存活率的假设。 Ⅰ型 干扰素可以诱导抗炎细胞因子 IL-10 的产生，我们最近证明了这一点 抑制肺部对肺炎链球菌感染的保护。在这里，我们研究IL-10是否 Poly(I:C) 处理的小鼠中的信号传导增强了中耳侵袭后肺炎链球菌的存活率，并且 IL-10对中耳炎症的影响。这些实验将共同确定 I 型是否 IFN 有助于肺炎链球菌 OM 的发病机制。在第二个目标中，我们研究了 宿主微生物组。使用抗生素治疗的儿童容易感染复发性细菌性 OM 和病原体 包括肺炎链球菌在内的细菌比许多共生（非致病性）物种对抗生素具有更强的耐药性。在 初步数据显示，我们发现抗生素治疗的小鼠增加了肺炎链球菌的侵袭并减少了 中性粒细胞募集到中耳。我们研究微生物组依赖性中性粒细胞的重要性 中耳侵入后早期清除肺炎链球菌的招募。在上呼吸道， 流行的共生棒状杆菌已通过下一代测序鉴定为阴性 与儿童的 OM 相关，表明具有潜在的保护作用。这里我们判断是否 棒状杆菌在我们的小鼠模型中提高了对肺炎链球菌 OM 的保护，这是迈向这一目标的第一步 开发新的基于益生菌的儿童 OM 方法。这些研究的长期目标是 开发新的免疫疗法和/或益生菌策略来改善 OM 疾病的负担。

Project Summary This proposal addresses the clinically significant issue of bacterial otitis media (OM), a major source of hospital visits and preventable hearing loss in young children and the most common diagnosis for antibiotic prescriptions in this age group. Streptococcus pneumoniae is one of the two most common causes of bacterial OM, which results from bacterial invasion from the nasopharynx to the middle ear. Despite widespread vaccine use, S. pneumoniae remains a significant OM pathogen, indicating the need for new therapeutic approaches. However, large knowledge gaps remain regarding the host factors which contribute to bacterial OM pathogenesis. To address these knowledge gaps, we developed a new mouse model of S. pneumoniae invasion to the middle ear. This model is based on the clinical observation that viral co-infection increases OM risk in children, and in mice promotes S. pneumoniae invasion. We find that serial administration of the viral dsRNA analog poly(I:C) is sufficient to promote S. pneumoniae invasion to the middle ear. Poly(I:C) induces the production of type I interferons (IFNs), which contribute to S. pneumoniae survival in other tissues. In the first Aim, we address the hypothesis that type I IFNs enhance S. pneumoniae survival in the middle ear. Type I IFNs can induce production of the anti-inflammatory cytokine IL-10, which we recently demonstrated suppresses protection against S. pneumoniae infection in the lung. Here, we investigate whether IL-10 signaling in poly(I:C) treated mice enhances S. pneumoniae survival following middle ear invasion, as well as the impact of IL-10 on middle ear inflammation. Together, these experiments will determine whether type I IFNs contribute to S. pneumoniae OM pathogenesis. In the second Aim, we investigate the importance of the host microbiome. Children treated with antibiotics are susceptible to recurrent bacterial OM, and pathogens including S. pneumoniae are more resistant to antibiotics than many commensal (non-pathogenic) species. In preliminary data, we find that antibiotic treated mice have increased S. pneumoniae invasion and reduced neutrophil recruitment to the middle ear. We investigate the importance of microbiome-dependent neutrophil recruitment for early clearance of S. pneumoniae following middle ear invasion. In the upper airway, the prevalent commensal Corynebacterium has been identified by next-generation sequencing as negatively correlated with OM in children, indicating a potentially protective role. Here, we determine whether Corynebacterium improves protection against S. pneumoniae OM in our mouse model as a first step toward developing new probiotic-based approaches for OM in children. The long-term goal of these studies is to develop novel immunotherapy and/or probiotic strategies to improve the burden of OM disease.