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

基本信息

批准号：
10386875
负责人：
Jian-Dong Li
金额：
$ 46.01万
依托单位：
GEORGIA STATE UNIVERSITY
依托单位国家：
美国
项目类别：
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/10386875
关键词：
Accounting Acute Adenosine Antibiotic Resistance Antibiotic Therapy Antibiotics Bacterial Infections 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 childhood hearing loss 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

项目摘要

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，通过提供粘膜天然防御作用，在粘膜先天防御中发挥着关键作用。粘液纤毛清除的物理屏障和捕获病原体如果不受控制，则会产生过多的粘蛋白。压倒粘膜纤毛清除功能，导致中耳炎 (OM) 和粘液传导性听力损失因此，粘蛋白的产生必须受到分子的严格调控。粘蛋白严格调节的机制仍然很大程度上未知。中耳炎 (OM) 是最常见的儿童细菌感染，也是传导性耳炎的主要原因听力损失仍然是一个主要的健康问题和严重的慢性负担。代表 OM 的主要革兰氏阳性细菌病原体。目前可用的 Sp 疫苗数量有限。此外，不适当的抗生素使用会增加抗生素耐药性。开发创新的非抗生素治疗剂来抑制粘液过度产生我们的长期计划。目标是阐明 OM 发病机制的分子机制并确定治疗新药与相对众所周知的 Toll 样受体 (TLR) 依赖性机制相反，Sp 和肺炎球菌溶血素（PLY——几乎所有临床 Sp 分离株产生的关键毒力因子）可诱导宿主粘膜免疫反应中，TLR 独立机制（包括关键调节因子）目前仍不清楚。腺苷 5’-单磷酸激活蛋白激酶 α1 (AMPKα1) 已成为宿主的主要调节因子它在传染病中的作用，特别是在宿主粘膜先天防御反应中的作用，我们令人鼓舞的初步数据表明，Sp 和 PLY 可能会影响粘液的产生。通过以 TLR2/4 独立的方式激活 AMPKα1 上调粘蛋白 MUC5AC 和 MUC5B 体外以及急性和慢性 OM 小鼠模型中的中耳和气道上皮细胞。 Sp 和 PLY 可能通过诱导新的非传统（蛋白质降解）激活 AMPKα1 AMPKα1 的泛素化可能是通过下调关键的去泛素酶 CYLD 来实现的。因此，令人兴奋的初步数据为我们捕获 [1] AMPKα1 作为一个 Sp 诱导的 MUC5AC 和 MUC5B 通过 TLR 独立信号传导上调的关键调节因子 [2] 通过多聚泛素化和磷酸化之间的相互作用激活 AMPKα1 在 Sp- 诱导 MUC5AC 和 MUC5B 上调（假设）为了检验我们的假设，我们将追求两个具体的结果。旨在确定（目标 1）AMPKα1 在 AOM 和 COM 的 OM 发病机制中的作用，以及（目标 2）如何发挥作用； Sp 激活 AMPKα1。这些研究将显着增进我们对关键调节因子的理解，包括 AMPK 在细菌感染中独立于 TLR 的宿主粘膜先天防御中的作用，并导致识别我们的 AMPK 信号传导研究也可能有所帮助。其他 AMPK 相关疾病的分子机制（意义和影响）。