Novel regulation of mucosal innate defense by AMPK in Otitis Media

AMPK 对中耳炎粘膜先天防御的新调节

• 批准号: 10229198
• 负责人: Jian-Dong Li
• 金额: $ 45.98万
• 依托单位: GEORGIA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-07 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10229198
• 关键词: Accounting; Acute; Adenosine; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Bacterial Infections; Child; Childhood; Chronic; Clinical; Communicable Diseases; Conductive hearing loss; Data; Development; Disease; Down-Regulation; Epithelial Cells; Foundations; Goals; Health; Homeostasis; In Vitro; Inflammation; Lead; Link; Lung infections; Lysine; MUC5AC gene; MUC5B gene; Mediating; Molecular; Mucins; Mucociliary Clearance; Mucosal Immune Responses; Mucous Membrane; Mucous body substance; Obstruction; Otitis Media; Pathogenesis; Phosphorylation; Play; Polyubiquitination; Production; Protein Kinase; Proteins; Public Health; Regulation; Role; Serotyping; Signal Transduction; Solid; Streptococcus pneumoniae; Streptococcus pneumoniae plY protein; TLR2 gene; Testing; Therapeutic; Therapeutic Agents; Threonine; Toll-like receptors; Ubiquitination; Up-Regulation; Vaccines; Virulence Factors; Visit; airway epithelium; cost; defense response; human disease; innovation; middle ear; mouse model; new therapeutic target; novel; novel therapeutic intervention; novel therapeutics; pathogen; pathogenic bacteria; pathogenic microbe; protein degradation; socioeconomics; vaccine access; virtual

Mucin, a major protein component in mucus, plays a critical role in mucosal innate defense by providing a physical barrier and trapping pathogens for mucociliary clearance. If uncontrolled, excessive mucin production overwhelms mucociliary clearance and causes conductive hearing loss in otitis media (OM) and mucus obstruction in lung infections. Therefore, mucin production must be tightly regulated. However, the molecular mechanisms underlying the tight regulation of mucin remain largely unknown. Otitis media (OM) is the most common childhood bacterial infection and the leading cause of conductive hearing loss. It remains a major health problem and a substantial socioeconomic burden. S. pneumoniae, Sp, represents a major gram-positive bacterial pathogen for OM. Currently available Sp vaccines have a limited impact on OM. Moreover, inappropriate antibiotic use increased antibiotic-resistance. There is an urgent need for developing innovative non-antibiotic therapeutic agent for suppressing mucus overproduction. Our long-term goal is to elucidate the molecular mechanisms underlying OM pathogenesis and identify novel therapeutic targets. In contrast to the relatively well-known toll-like receptor (TLR)-dependent mechanisms by which Sp and pneumolysin (PLY – a key virulence factor produced by virtually all clinical Sp isolates) induce host mucosal immune response, the TLR-independent mechanisms including the key regulators remain largely unclear. Adenosine 5’-monophosphate-activated protein kinase α1 (AMPKα1) has emerged as a master regulator of host energy homeostasis. Its role in infectious diseases, in particular in the host mucosal innate defense response, e.g. mucus production, remains largely unclear. Our encouraging preliminary data suggest that Sp and PLY may up-regulate mucin MUC5AC and MUC5B via activation of AMPKα1 in a TLR2/4-independent manner in the middle ear and airway epithelial cells in vitro and in the mouse models of both acute and chronic OM. Interestingly, Sp and PLY may activate AMPKα1 by inducing novel non-traditional (protein degradation- independent) ubiquitination of AMPKα1 likely via downregulating a key deubiquitinase CYLD. Together, these exciting preliminary data have thus provided a solid foundation for us to hypothesize that [1] AMPKα1 acts as a key regulator for Sp-induced up-regulation of MUC5AC and MUC5B via TLR-independent signaling; [2] Activation of AMPKα1 by interplay between polyubiquitination and phosphorylation plays a critical role in Sp- induced up-regulation of MUC5AC and MUC5B (hypothesis). To test our hypothesis, we will pursue two specific aims to determine (Aim 1) the role of AMPKα1 in OM pathogenesis in both AOM and COM; and (Aim 2) how Sp activates AMPKα1. These studies will significantly advance our understanding of the key regulators including AMPK in TLR-independent host mucosal innate defense in bacterial infections and lead to the identification of novel therapeutic targets for controlling mucus overproduction. Our AMPK signaling studies may also help understand molecular mechanisms of other AMPK-related diseases (Significance and Impact).

粘蛋白是粘液中的主要蛋白质成分，在粘膜天生防御中起着至关重要的作用 物理障碍和诱捕病原体，用于粘膜毛的清除率。如果不受控制，粘蛋白产生过多 压倒性的粘膜缩减清除率，导致中耳炎（OM）和粘液中导电性听力损失 肺部感染的阻塞。因此，必须严格调节粘蛋白的产生。但是，分子 严格调节粘蛋白的机制在很大程度上未知。 中耳炎培养基（OM）是最常见的儿童细菌感染，也是导电的主要原因 听力损失。它仍然是一个重大的健康问题和重大的社会经济负担。 S.肺炎，SP， 代表OM的主要革兰氏阳性细菌病原体。目前可用的SP疫苗有限 对OM的影响。此外，不适当的抗生素使用增加了抗生素耐药性。迫切需要 用于开发创新的非抗生素治疗剂，以抑制粘液过量生产。我们的长期 目标是阐明OM发病机理的分子机制并确定新的治疗 目标。与相对众所周知的Toll样接收器（TLR）依赖性机制相反，SP和 肺炎（PLY - 几乎所有临床SP分离株产生的关键病毒因子）诱导宿主粘膜 免疫反应，包括关键调节剂在内的TLR独立机制仍然在很大程度上不清楚。 腺苷5'单磷酸激活的蛋白激酶α1（AMPKα1）已成为宿主的主要调节剂 能量稳态。它在传染病中的作用，尤其是在宿主粘膜先天防御反应中的作用， 例如粘液产生，在很大程度上不清楚。我们令人鼓舞的初步数据表明，SP和PLY可能 通过以TLR2/4非依赖性的方式激活AMPKα1，在上调粘蛋白MUC5AC和MUC5B 中耳和气道上皮细胞在体外以及急性和慢性OM的小鼠模型中。 有趣的是，SP和PLY可能会通过诱导的新型非传统（蛋白质降解）激活AMPKα1 独立的）AMPKα1的泛素化可能是通过下调关键的去泛素酶CYLD的。在一起，这些 因此，令人兴奋 通过独立的信号传导，用于SP诱导MUC5AC和MUC5B上调的关键调节剂； [2] 通过多泛素化和磷酸化之间的相互作用激活AMPKα1在SP-中起关键作用 诱导的MUC5AC和MUC5B上调（假设）。为了检验我们的假设，我们将追求两个特定的 旨在确定（目标1）AMPKα1在AOM和COM中OM发病机理中的作用； （目标2）如何 SP激活AMPKα1。这些研究将大大提高我们对关键监管机构的理解 非依赖TLR的宿主粘膜先天防御细菌感染中的AMPK，并导致鉴定 用于控制粘液过量生产的新型热靶标。我们的AMPK信号研究也可能有助于 了解其他与AMPK相关疾病的分子机制（显着性和影响）。