Understanding and Enhancing Repair of the Ear Drum

了解和加强耳膜修复

• 批准号: 2290197
• 金额: --
• 依托单位: King's College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2290197
• 关键词: Understanding; Enhancing; Repair; Ear; Drum

Tympanic membrane (ear drum) perforation (TMP) is a highly prevalent clinical problem, particularly common in young children. TMPs can result from physical trauma, pressure changes and, most commonly, from acute otitis media (AOM) a disease which almost all children will suffer from before the age of three (1). TMPs occur in 29.5% of children with AOM, with increased incidence associated with a previous history of OM (2). Although the majority of TMPs spontaneously heal within 2 weeks, approximately 6% do not heal and become chronic. In patients, TMPs can fail to spontaneously heal due to a range of factors. The hole may be too large to allow repair (3) or may form an epithelial ridge preventing further healing (4). Infectious factors, involved with AOM, also inhibit healing. Perforations involving the malleus also appear to be problematic (5). Chronic TMPs lead to complications including recurrent infections, middle ear cysts, otalgia, tinnitus and conductive hearing loss and have to be treated surgically (Type 1 Tympanoplasty or Myringoplasty). This proposal aims to uncover the mechanisms involved in perforation healing in order to enhance healing in TMPs that do not heal naturally. Due to the ability of the TM to spontaneously heal it has been suggested that the membrane must harbour its own stem/progenitor cell populations. Several groups have used the epidermal SC markers a6-integrin, B1 -integrin and cytokeratin 19 (CK19) to look for SCs in human and rat TMs. Positive staining for these markers was observed along the manubrium and around the annulus, at the edge of the membrane and after perforation a significant increase in expression of these markers was observed [6]. Wnt signalling is central to the control of stem/progenitor cell activity in a number of organs and may act as a niche factor to maintain stem cells in a self-renewing state. In addition, As part of a preliminary study to investigate whether Wnts may play a role in control of the stem/progenitor cells in the TM we looked at Wnt activity in the TM using the Axin2lacZ reporter mouse. Cells responding to Wnt activity were located in the annulus region of the TM and around the manubrium, matching the general pattern of other putative stem cell markers. Wnt signalling is therefore active in a discrete population of cells within the membrane. The Tucker lab has developed a TMP protocol for studying ear drum perforations in mice in vivo and in explant culture and has a collection of transgenic models for studying the problem. The research is supported by a postdoc on an MRC funded project grant on ear drum repair. The Tucker lab has particular expertise in middle and external ear development and repair and have published a number of papers in this area. Prof Jiang is an ear surgeon and will provide his expertise in dealing with chronic TMPs in patients.We aim to understand how the ear drum repairs itself during injury (the cells and signalling pathways involved) and how to enhance healing of problematic holes. Homeostasis: what cells contribute to turnover in the ear drum? Wnt responding cells (Axin2creERT2Tom label) Lineage tracing repair. What cells respond to injury? Neural crest, endoderm, mesoderm, ectoderm? Cres: Wnt1cre, Mesp1cre, Sox17icre, Sox2ert2cre, K14cre, K14ert2cre, Axin2ert2cre How does manipulating Wnt signalling impact on repair? Overexpresssion GOF mice, Axin2 mice, loss of function Wntless mice Cres: Pcagcre, K14ert2cre, Sox2ert2cre How does manipulating signalling pathways impact repair in vitro: use of explant cultures? Effect on vasculature Mesp1cretom mice Pharmacological impact on repair

鼓膜穿孔（TMP）是一种非常普遍的临床问题，特别是在幼儿中常见。TMP可由物理创伤、压力变化以及最常见的急性中耳炎（AOM）引起，急性中耳炎是一种几乎所有儿童在三岁之前都会患有的疾病（1）。29.5%的AOM儿童发生TMP，与既往OM病史相关的发病率增加（2）。虽然大多数TMP在2周内自发愈合，但约6%不愈合并成为慢性。在患者中，由于一系列因素，TMP可能无法自发愈合。孔可能太大而不允许修复（3）或可能形成上皮嵴，阻止进一步愈合（4）。与AOM有关的感染因素也抑制愈合。涉及锤骨的穿孔似乎也有问题（5）。慢性鼓室成形术会导致并发症，包括复发性感染、中耳囊肿、耳痛、耳鸣和传导性听力损失，必须进行手术治疗（1型鼓室成形术或鼓膜成形术）。该提案旨在揭示穿孔愈合中涉及的机制，以增强不能自然愈合的TMP的愈合。由于TM能够自发愈合，因此已经提出膜必须具有其自身的干/祖细胞群。几个研究小组已经使用表皮SC标志物α 6-整联蛋白、β 1-整联蛋白和细胞角蛋白19（CK 19）来寻找人和大鼠TM中的SC。在沿着瓣环和瓣环周围、膜边缘观察到这些标志物的阳性染色，穿孔后观察到这些标志物的表达显著增加[6]。Wnt信号传导是许多器官中干/祖细胞活性控制的核心，并且可以作为小生境因子来维持干细胞处于自我更新状态。此外，作为调查Wnt是否可以在TM中的干/祖细胞的控制中发挥作用的初步研究的一部分，我们使用Axin 2lacZ报告小鼠观察了TM中的Wnt活性。响应Wnt活性的细胞位于TM的环区域和手周围，与其他假定的干细胞标志物的一般模式相匹配。因此，Wnt信号传导在膜内的离散细胞群中是活跃的。Tucker实验室已经开发了一种TMP方案，用于研究小鼠体内和外植体培养中的鼓膜穿孔，并收集了一系列用于研究该问题的转基因模型。这项研究得到了MRC资助的鼓膜修复项目的博士后的支持。Tucker实验室在中耳和外耳发育和修复方面具有特殊的专业知识，并在该领域发表了许多论文。姜教授是一位耳外科医生，他将提供他处理慢性鼓膜穿孔的专业知识。我们的目标是了解鼓膜在损伤过程中如何自我修复（涉及的细胞和信号通路），以及如何促进有问题的穿孔的愈合。 稳态：哪些细胞有助于鼓膜的周转？Wnt应答细胞（Axin 2creERT 2 Tom标记）谱系追踪修复。哪些细胞会对损伤做出反应？神经嵴，内胚层，中胚层，外胚层？克雷斯：Wnt 1cre，Mesp 1cre，Sox 17 icre，Sox 2 ert 2cre，K14 cre，K14 ert 2cre，Axin 2 ert 2cre如何操纵Wnt信号对修复的影响？过度表达GOF小鼠，Axin 2小鼠，功能丧失Wntless小鼠克雷斯：Pcagcre，K14 ert 2cre，Sox 2 ert 2cre操纵信号通路如何影响体外修复：使用外植体培养物？对血管系统的影响Mesp 1cretom小鼠对修复的药理学影响