Molecular etiology of virus-induced sensorineural hearing loss

项目摘要 病毒感染是感音神经性耳聋(SNHL)的常见原因。然而，潜在的机制是 人们对此知之甚少。对于大多数病毒来说，SNHL是否由内耳直接病毒感染引起尚不清楚。 组织或通过免疫反应产生的次要作用，或两者的组合。抗病毒药物和 类固醇只能改善一小部分患者的预后。因此，必须了解 病毒诱导SNHL的分子病因学研究为开发有效的预防和治疗方法提供了理论依据。这个 研究建议使用腮腺炎病毒(Muv)系统地评估病毒对内耳的影响。 出生后引起SNHL的病毒(获得性SNHL)和小鼠巨细胞病毒(MCMV)了解人类 在胚胎发育过程中引起SNHL的巨细胞病毒病(先天性SNHL)。世界上没有小动物 MUV引起SNHL的评估模型。在Aim1中，建议建立新的活体小鼠模型以 评估MCMV和MuV感染如何影响内耳细胞。感染将在当地进行，并通过 后半规管。听力损失的开始和程度将通过听性脑干来测量 响应和失真产物耳声发射。组织化学将对病毒感染的凋亡细胞进行量化 细胞和免疫细胞位于耳蜗尖到底部的特定解剖位置。 因为这个模型是 预计将高度可控，它将进行优化，以使不同病毒的有害机制 可以比较，以促进对病毒诱导的SNHL的机制的了解。AIM2专注于 了解MCMV和MCMV中组织损伤的病原学--直接病毒感染或免疫反应-- 并从细胞和分子水平分析其作用机制。敏感细胞 将量化P2和P21小鼠在发病前后注射MCMV和Muv的亚型 使用已知和最近识别的标记物造成听力损失。这些包括新的绒毛周围细胞亚型 首席调查员(PI)最近报道的新生儿耳蜗病以及新的亚型 属于I型螺旋神经节细胞。一种称为GM2的神经节苷脂的表达，这是PI鉴定的一种MIV受体 在之前的研究中，各种病毒宿主因子也将在每个耳蜗细胞亚型中进行量化，以 了解它们与细胞损伤的相关性。此外，浸润性免疫细胞的类型和数量 PSC注射MCMV和Muv后，将用流式细胞仪分析P2和P21小鼠的MCMV和MUV 特定于细胞类型的标记。总之，完成这些目标将提供关于以下机制的基本细节 由MCMV和MUV引起的SNHL，并将建立一个可应用于其他听力损失的协议 病毒，如拉萨病毒，由于其高度的生物安全性而不适合动物模型开发 水平。PI设想这个项目是她未来研究旅程的第一步，她是一名临床医生兼科学家，拥有 重点预防和治疗病毒引起的SNHL。

PROJECT ABSTRACT Viral infection is a common cause of sensorineural hearing loss (SNHL). However, the underlying mechanism is poorly understood. For most viruses, it is unclear whether SNHL is caused by direct viral infection of inner ear tissue or by a secondary effect through an immune response, or a combination of both. Antiviral drugs and steroids only improve the outcome for a small group of patients. It is therefore imperative to understand the molecular etiology of virus-induced SNHL for the development of effective preventions and treatments. The research proposes a systemic evaluation of viral effects on the inner ear using mumps virus (MuV), a human virus that causes SNHL after birth (acquired SNHL), and murine cytomegalovirus (mCMV) to understand human CMV disease that causes SNHL during embryonic development (congenital SNHL). There is no small animal model to assess SNHL caused by MuV. In Aim1, it is proposed to establish novel in vivo mouse models to assess how mCMV and MuV infections affect inner ear cells. Infection will be done locally and controlled via the posterior semicircular canal. The onset and extent of hearing loss will be measured by auditory brainstem response and distortion product otoacoustic emissions. Histochemistry will quantify apoptotic cells, virus-infected cells, and immune cells in defined anatomical locations of the cochlea from apex to base. Because the model is expected to be highly controllable, it will be optimized so that the detrimental mechanisms of different viruses can be compared to advance the mechanistic understanding of virus-induced SNHL. Aim2 focuses on understanding the etiology of the tissue damage -direct viral infection or immune response- in mCMV- and MuV- administrated cochleae, and to analyze the mechanisms at the cellular and molecular level. Susceptible cell subtypes will be quantified in P2 and P21 mice injected with mCMV and MuV before and after the onset of hearing loss by using known and recently identified markers. These include new pericochlear cell subtypes in the neonatal cochlea that were recently reported by the principal investigator (PI), as well as the new subtypes of type I spiral ganglion cells. The expression of a ganglioside called GM2, a MuV receptor which the PI identified in a previous study, and various viral host factors will be also quantified in each cochlear cell subtype to understand their correlation with cellular damage. Further, the types and numbers of infiltrating immune cells post PSC injection of mCMV and MuV in P2 and P21 mice will be assessed with flow cytometric analysis with cell type-specific markers. Together, completion of these aims will provide essential details of the mechanism of SNHL caused by mCMV and MuV, and will establish a protocol that can be applied to other hearing loss-causing viruses such as Lassa virus, which is not suitable for animal model development because of its high biosafety level. The PI envisions this project as the first step of her future research journey as a clinician-scientist with a focus on prevention and treatment of viral-induced SNHL.