Combinational Regulation of Inflammation in Otitis Media

描述(申请人提供)：中耳炎(OM)是最常见的儿童细菌感染，也是儿童传导性听力损失的主要原因。炎症是OM的一个特征。开发高效疫苗仍然是一个巨大的挑战。不适当的抗生素治疗大大增加了抗生素的耐药性。目前，由于对炎症的发病机制和有效的治疗靶点知之甚少，目前尚无有效的治疗方法包括抗炎药物。虽然适当的炎症对于根除病原体是必不可少的，但过度的炎症显然对宿主有害。因此，必须严格控制炎症。然而，炎症是如何受到严格调控的仍不清楚。我们的长期目标是了解炎症在OM中受到严格调控的分子机制，并确定有效的治疗靶点。在之前的资助期间，我们发现了一种新的脱泛素酶CyLD，它是严格控制NTHi细菌引起的OM炎症的关键负调控因子。鉴于过去在开发抗炎药方面的努力，大多数策略都集中在直接针对积极的途径，如I？B激酶(IKK)，以抑制炎症。虽然这些药物通常显示出合理的疗效，但它们确实显示出显著的副作用，例如增加了对感染和细胞凋亡的易感性，这阻碍了它们的进一步临床应用。因此，我们推测，通过药物抑制其自身的负性调节因子，上调炎症的关键负性调节因子CyLD，可能代表了一种新的、有利的抗炎策略，用于治疗OM中过度活跃的炎症，而不会引起通常与靶向正性炎症调节因子一起出现的严重不良反应(假设和创新)。事实上，我们的初步研究表明，CyLD本身进一步受到PDE4的负面控制；PDE4的药理抑制可能通过上调CyLD的表达而抑制炎症。这些初步数据为我们研究PDE4B-JNK2途径负调控CyLD的分子机制，以及通过抑制自身负调控因子上调CyLD在NTHi诱导的OM炎症中的治疗作用(短期目标)奠定了坚实的基础。我们的具体目标是：目的1.确定PDE4B是否在体外和体内通过抑制CyLD在介导NTHi诱导的炎症反应中起关键作用。目的：研究PDE4B在体内外通过选择性激活JNK2抑制CyLD，从而调节NTHi诱导的炎症反应的机制。目的3.确定PDE4B对NTHi诱导的小鼠OM模型炎症的治疗作用。总体而言，这些研究将促进我们对OM分子发病机制的理解，并有助于发现治疗OM的新靶点和新的抗炎药。 公共卫生相关性：-与公共卫生中耳炎(OM)相关，中耳炎是儿童最常见的细菌感染，每年就诊2450万人次，花费超过50亿美元，也是儿童传导性听力损失的主要原因。发展高效的OM疫苗仍然是一个巨大的挑战，不适当的抗生素治疗大大增加了抗生素的耐药性，由于对炎症的发病机制和有效的治疗靶点缺乏了解，目前还没有包括抗炎药在内的有效治疗OM的药物。目前提出的研究将促进我们对OM的分子发病机制的了解，并导致识别新的治疗靶点和开发新的抗炎治疗策略来抑制OM的炎症。

DESCRIPTION (provided by applicant): Otitis media (OM) is the most common childhood bacterial infection and also the leading cause of conductive hearing loss in children. Inflammation is a hallmark of OM. Developing highly effective vaccines still remains a great challenge. Inappropriate antibiotic treatment increased antibiotic resistance substantially. Currently, there are no effective therapeutics including anti-inflammatory agents available for OM due to poor understanding of the pathogenic mechanism underlying inflammation and the effective therapeutic targets. Although appropriate inflammation is essential for eradicating pathogens, excessive inflammation is clearly detrimental to the host. Thus, inflammation must be tightly regulated. However, how inflammation is tightly regulated remains unknown. Our long-term objective is to understand the molecular mechanisms by which inflammation is tightly regulated in OM and to identify effective therapeutic targets. During previous grant period, we identified a novel deubiquitinase CYLD as the key negative regulator for tightly controlling NTHi bacteria-induced inflammation in OM. In view of the past effort in developing anti-inflammatory agents, most strategies have focused on directly targeting the positive pathways, e.g., the I?B kinase (IKK), to suppress inflammation. While these agents often showed reasonable efficacy, they did exhibit significant adverse effects, e.g., increased susceptibility to infection and apoptosis, which prevented their further clinical use. Thus, we hypothesized that up-regulating CYLD, the key negative regulator of inflammation, by pharmacological inhibition of its own negative regulator, may represent a novel and advantageous anti-inflammatory strategy for treating overactive inflammation in OM without causing serious adverse effects often seen with targeting positive regulator of inflammation (hypothesis & innovation). Indeed, our preliminary studies demonstrate that CYLD itself is further negatively controlled by PDE4; Pharmacological inhibition of PDE4 led to the suppression of inflammation by up-regulating CYLD expression likely via JNK. These preliminary data have thus laid a solid foundation for us to investigate the molecular mechanisms underlying negative regulation of CYLD by PDE4B-JNK2 pathway and evaluate the therapeutic effect of up-regulating CYLD by inhibiting its own negative regulator in NTHi-induced inflammation in OM (short-term objective). Our specific aims are: Aim 1. Determine if PDE4B is critical for mediating NTHi-induced inflammation by inhibiting CYLD in vitro & in vivo. Aim 2. Determine how PDE4B regulates NTHi-induced inflammation by inhibiting CYLD via selective activation of JNK2 in vitro & in vivo. Aim 3. Determine the therapeutic effect of PDE4B inhibition on NTHi-induced inflammation in a mouse OM model. Overall, the proposed studies will advance our understanding of molecular pathogenesis of OM and lead to identifying novel therapeutic targets and new anti-inflammatory agents for OM. PUBLIC HEALTH RELEVANCE: - Relevance to Public Health Otitis media (OM), inflammation of middle ear, is the most common childhood bacterial infection, accounting for 24.5 million visits and costing over $5 billion annually, and is also the leading cause of conductive hearing loss in children. Developing highly effective OM vaccines still remains a great challenge, inappropriate antibiotic treatment increased antibiotic resistance substantially and currently there are no effective therapeutics including anti-inflammatory agents available for OM due to poor understanding of the pathogenic mechanism underlying inflammation and the effective therapeutic targets. The currently proposed studies will advance our understanding of molecular pathogenesis of OM and lead to the identification of novel therapeutic targets and development of new anti-inflammatory therapeutic strategy for inhibiting inflammation in OM.