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

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.

Agency
National Institute of Health (NIH)
Type
Research Project (R01)
Project #
3R01DC005843-15S1
Application #
8915360
Study Section
Clinical Research and Field Studies of Infectious Diseases Study Section (CRFS)
Program Officer
Watson, Bracie
Project Start
Project End
Budget Start
Budget End
Support Year
15
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Georgia State University
Department
None
Type
Organized Research Units
DUNS #
City
Atlanta
State
GA
Country
United States
Zip Code
30302
Wang, Wenzhuo Y; Komatsu, Kensei; Huang, Yuxian et al. (2014) CYLD negatively regulates nontypeable Haemophilus influenzae-induced IL-8 expression via phosphatase MKP-1-dependent inhibition of ERK. PLoS One 9:e112516
Mittal, Rahul; Grati, M'hamed; Gerring, Robert et al. (2014) In vitro interaction of Pseudomonas aeruginosa with human middle ear epithelial cells. PLoS One 9:e91885
Li, Wen; Yan, Fugui; Zhou, Hongbin et al. (2013) P. aeruginosa lipopolysaccharide-induced MUC5AC and CLCA3 expression is partly through Duox1 in vitro and in vivo. PLoS One 8:e63945
Komatsu, Kensei; Lee, Ji-Yun; Miyata, Masanori et al. (2013) Inhibition of PDE4B suppresses inflammation by increasing expression of the deubiquitinase CYLD. Nat Commun 4:1684
Wang, Wenzhuo Y; Lim, Jae Hyang; Li, Jian-Dong (2012) Synergistic and feedback signaling mechanisms in the regulation of inflammation in respiratory infections. Cell Mol Immunol 9:131-5
Jono, Hirofumi; Lim, Jae Hyang; Xu, Haidong et al. (2012) PKCýý synergizes with TLR-dependent TRAF6 signaling pathway to upregulate MUC5AC mucin via CARMA1. PLoS One 7:e31049
Lim, Jae Hyang; Jono, Hirofumi; Komatsu, Kensei et al. (2012) CYLD negatively regulates transforming growth factor-ýý-signalling via deubiquitinating Akt. Nat Commun 3:771
Xu, Xiangbin; Steere, Rachel R; Fedorchuk, Christine A et al. (2011) Activation of epidermal growth factor receptor is required for NTHi-induced NF-?B-dependent inflammation. PLoS One 6:e28216
Lim, Jae Hyang; Woo, Chang-Hoon; Li, Jian-Dong (2011) Critical role of type 1 plasminogen activator inhibitor (PAI-1) in early host defense against nontypeable Haemophilus influenzae (NTHi) infection. Biochem Biophys Res Commun 414:67-72
Jeon, Kye-Im; Xu, Xiangbin; Aizawa, Toru et al. (2010) Vinpocetine inhibits NF-kappaB-dependent inflammation via an IKK-dependent but PDE-independent mechanism. Proc Natl Acad Sci U S A 107:9795-800

Showing the most recent 10 out of 31 publications