Combinational Regulation of Inflammation in Otitis Media

描述（申请人提供）：中耳炎（Otitis media， OM）是儿童最常见的细菌性感染，也是导致儿童传导性听力损失的主要原因。炎症是OM的标志。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耐药性。目前，由于对炎症的致病机制和有效治疗靶点的认识不足，尚无抗炎药等有效治疗OM的药物。虽然适当的炎症对消灭病原体至关重要，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得而知。我们的长期目标是了解炎症在OM中受到严格调节的分子机制，并确定有效的治疗靶点。在之前的资助期间，我们确定了一种新的去泛素酶CYLD作为严格控制NTHi细菌诱导的OM炎症的关键负调节因子。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阳性途径，例如I？B激酶（IKK），抑制炎症。虽然这些药物通常表现出合理的疗效，但它们确实表现出明显的不良反应，例如增加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，我们假设，通过药理抑制CYLD这一炎症的关键负调节因子，上调CYLD可能是一种新的、有利的抗炎策略，可以治疗OM中过度活跃的炎症，而不会引起靶向炎症正调节因子常见的严重不良反应（假设&创新）。事实上，我们的初步研究表明，CYLD本身进一步受到PDE4的负性控制；药理抑制PDE4可能通过JNK上调CYLD表达，从而抑制炎症。这些初步数据为我们研究PDE4B-JNK2通路负调控CYLD的分子机制，以及评价通过抑制CYLD自身负调控上调在nthi诱导的OM炎症中的治疗效果奠定了坚实的基础（短期目标）。我们的具体目标是：目标1。确定PDE4B是否在体外和体内通过抑制CYLD介导nthi诱导的炎症中起关键作用。目标2。确定PDE4B如何在体外和体内通过JNK2选择性激活抑制CYLD来调节nthi诱导的炎症。目标3。观察PDE4B抑制对小鼠OM模型nthi诱导炎症的治疗作用。总的来说，所提出的研究将促进我们对OM的分子发病机制的理解，并导致发现新的治疗靶点和新的抗炎药。

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.