The role of macrophages in chronic suppurative otitis media associated sensory hearing loss

巨噬细胞在慢性化脓性中耳炎相关感觉性听力损失中的作用

基本信息

批准号：
10544016
负责人：
Peter Luke Santa Maria
金额：
$ 68.25万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-01-01 至 2026-12-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10544016
关键词：
Animal Model Antibiotic Therapy Appearance Bacteria Bacterial Infections Bone Marrow Transplantation Brightfield Microscopy Cd68 Cell Death Cells Chemicals Child Chimera organism Chronic Cochlea Communities Confocal Microscopy Data Development Disease Dose Ear Fluoroquinolones Foundations Functional disorder Future Hair Cells Human Immune Immunohistochemistry Infection Infiltration Inflammasome Injury Invaded Investigation Kinetics Knock-out Knockout Mice Labyrinth Liquid substance Location Macrophage Macrophage Activation Mediating Medical Microbial Biofilms Modeling Monitor Mouse Strains Mus Nature Otitis Media Outer Hair Cells Pattern Perilymph Persons Phagocytes Pharmacotherapy Phenotype Population Process Pseudomonas aeruginosa Reaction Reactive Oxygen Species Reporter Genes Role Sampling Scanning Electron Microscopy Secondary to Sectioning technique Sensorineural Hearing Loss Signal Transduction Suppurative Otitis Media Testing Therapeutic Intervention Time Topical Antibiotic Toxin Transgenic Organisms Transmission Electron Microscopy Tympanic membrane United States National Institutes of Health Waxes World Health acute infection cell injury cytokine effective therapy hearing impairment human disease middle ear middle ear fluid migration monocyte mouse model neglect neglected tropical diseases novel novel strategies permanent hearing loss prevent prevent hearing loss recruit

项目摘要

Project Summary / Abstract We request NIH support to investigate how sensory hearing loss (SHL) is caused by chronic suppurative otitis media (CSOM) or severe chronic middle ear infections. CSOM, a neglected tropical disease that afflicts 330 million people worldwide, is the most common cause of permanent hearing loss among children in the developing world. It is characterized by a chronically discharging infected middle ear, and there is currently no effective medical therapy or cure. The bacterium, Pseudomonas aeruginosa (PA), is the leading culprit. PA colonizes the middle ear via a hole in the tympanic membrane and establishes itself into a biofilm community, complicating attempts to treat and fully eradicate infection. Over the course of the disease, the infection waxes and wanes as the population of bacteria within the biofilm responds, in part, to immune attack or topical antibiotics. This waxing and waning of bacterial infection leads to permanent sensory hearing loss via an unknown mechanism. Our lab has recently created and validated a novel PA CSOM animal model that mimics the human condition. Specifically, we create the infection by inoculating PA in the right state (phenotype) and dose, which results in an infection that persists beyond six months, waxes and wanes upon topical fluoroquinolone therapy, and leads to hair cell death, over time, like in the human disease. Previous investigations by others relied on acute infection models based on non-PA bacteria. In contrast, our unique model of PA CSOM now allows us to observe development of the infection in the inner ear and identify agents and/or processes that may be causing the resulting sensory hearing loss. Our studies would help determine whether permanent hearing loss is preventable in CSOM and, if so, guide strategies for therapeutic intervention. Our Aims encompass: (1) determining the timing and nature of structural changes occurring within the cochlea and assessing the macrophage distribution as these changes occur, (2) investigating potential direct hair cell (HC) toxins and macrophage inducers through CSOM perilymph sampling, and (3) evaluating the contributions of resident and migrating macrophages towards hair cell loss in CSOM by combining our CSOM mouse model with the CD68-GFP transgenic reporter mouse and, separately, with a triple knockout mouse strain with macrophages unable to produce reactive oxygen species (ROS) while also evaluating whether NLRP3 inflammasome function is necessary for HC loss in the cochlea. Altogether these aims are a completely new approach to sensory hearing loss caused by CSOM. If successful, these studies will support future investigations into the mechanisms in the pathophysiology of CSOM and lead to novel treatments for PA and potential strategies to prevent sensory hearing loss in CSOM.

项目概要/摘要我们请求 NIH 支持调查慢性化脓性中耳炎如何导致感觉性听力损失 (SHL) 中耳炎 (CSOM) 或严重的慢性中耳感染。 CSOM，一种被忽视的热带疾病，困扰着 330 人是全球儿童永久性听力损失的最常见原因发展中国家。其特点是感染中耳慢性分泌物，目前尚无治疗方法。有效的药物治疗或治愈。铜绿假单胞菌（PA）是罪魁祸首。 PA 通过鼓膜上的孔定植于中耳，并建立生物膜群落，使治疗和完全根除感染的尝试变得复杂化。在疾病过程中，感染逐渐加重并随着生物膜内的细菌种群对免疫攻击或局部局部反应做出反应而减弱抗生素。细菌感染的此消彼长会通过一种机制导致永久性的感觉性听力损失。未知的机制。我们的实验室最近创建并验证了一种新颖的 PA CSOM 动物模型，该模型模仿人类状况。具体来说，我们通过在正确的状态（表型）下接种 PA 来产生感染，剂量，导致感染持续超过六个月，局部使用时会出现变化氟喹诺酮治疗，随着时间的推移会导致毛细胞死亡，就像人类疾病一样。以前的其他人的研究依赖于基于非 PA 细菌的急性感染模型。相比之下，我们独特的 PA CSOM 模型现在使我们能够观察内耳感染的发展并识别病原体和/或可能导致感觉性听力损失的过程。我们的研究将有助于确定 CSOM 是否可以预防永久性听力损失，如果可以，请指导治疗干预策略。我们的目标包括：(1) 确定耳蜗内发生结构变化的时间和性质并评估发生这些变化时的巨噬细胞分布，(2) 研究潜在的直接毛细胞通过 CSOM 外淋巴取样 (HC) 毒素和巨噬细胞诱导剂，以及 (3) 评估贡献通过结合我们的 CSOM 小鼠模型，观察驻留型和迁移型巨噬细胞对 CSOM 中毛细胞损失的影响使用 CD68-GFP 转基因报告小鼠，并分别使用具有以下特征的三重敲除小鼠品系：巨噬细胞无法产生活性氧 (ROS)，同时还评估 NLRP3 是否炎症小体功能是耳蜗 HC 损失所必需的。总而言之，这些目标是针对 CSOM 引起的感觉性听力损失提供一种全新的方法。如果成功的话，这些研究将支持未来对 CSOM 病理生理学机制的研究并导致 PA 的新治疗方法以及预防 CSOM 感觉性听力损失的潜在策略。