Otitis media is a major health problem causing substantial morbidity and resulting in substantial health care expenditures. The causes and treatment of this disorder remain incompletely understood. Eustachian tube obstruction, viral and subsequent bacterial infection and immunity have each been suggested to contribute to the etiopathophysiology of this disorder. Recent work in our laboratories has indicated that concurrent mast cell activation and bacterial infection can synergistically interact to induce strong inflammatory changes in the middle ear. These preliminary data, as well as prior research in the middle ear and other systems, suggest that the mast cell may play an important role in the innate and cognate defense of the middle ear, and may also contribute to otitis media pathogenesis. In this proposal Drs. S. Wasserman, A. Ryan and D. Broide propose a series of integrated experiments employing genetically modified mice to validate this hypothesis and to elucidate the mechanism(s) by which this synergistic interaction occurs.
Aim 1 of this proposal will define the synergistic interaction utilizing mast cell deficient mice, with and without, reconstitution of their middle ear mast cells.
Aim 2 will examine the mechanisms by which bacterial products enhance mast cell mediated synergistic inflammation by exploring the Toll-like receptor (TLR) pathways of mast cells. In these experiments TLR 2, 4, and 9 deficient mast cells will be used to re-constitute middle ear mast cell populations of mast cell deficient mice and the effect of bacterial/ mast cell interactions defined. MyD88 deficient mice, defective in all TLR signaling will be used to define potential redundancies in these responses.
Aim 3 will re-constitute middle ear mast cells with mast cell populations obtained from mice which are deficient in one or more mast cell mediators including histamine, leukotriene and tumor necrosis factor alpha to define the mediator(s) responsible for mast cell enhancement of inflammation induced in the presence of bacteria.
Aim 4 will elucidate the leukocyte/endothelial mechanisms by which mast cell] bacterial interactions enhance inflammation, by direct observations of leukocyte behavior in genetically modified animals. Together these studies will expand our understanding of the role of mast cells in otitis media and may identify new targets for therapeutic intervention. ? ?

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZDC1-SRB-A (40))
Program Officer
Watson, Bracie
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of California San Diego
Internal Medicine/Medicine
Schools of Medicine
La Jolla
United States
Zip Code
Deniffel, Dominik; Nuyen, Brian; Pak, Kwang et al. (2017) Otitis Media and Nasopharyngeal Colonization in ccl3-/- Mice. Infect Immun 85:
Kurabi, Arwa; Pak, Kwang; Ryan, Allen F et al. (2016) Innate Immunity: Orchestrating Inflammation and Resolution of Otitis Media. Curr Allergy Asthma Rep 16:6
Hernandez, Michelle; Leichtle, Anke; Pak, Kwang et al. (2015) The transcriptome of a complete episode of acute otitis media. BMC Genomics 16:259
Leichtle, Anke; Klenke, Christin; Ebmeyer, Joerg et al. (2015) NOD-Like Receptor Signaling in Cholesteatoma. Biomed Res Int 2015:408169
Kurabi, Arwa; Lee, Jasmine; Wong, Chelsea et al. (2015) The inflammasome adaptor ASC contributes to multiple innate immune processes in the resolution of otitis media. Innate Immun 21:203-14
Yao, William; Frie, Meredith; Pan, Jeffrey et al. (2014) C-Jun N-terminal kinase (JNK) isoforms play differing roles in otitis media. BMC Immunol 15:46
Suzukawa, Keigo; Tomlin, Julia; Pak, Kwang et al. (2014) A mouse model of otitis media identifies HB-EGF as a mediator of inflammation-induced mucosal proliferation. PLoS One 9:e102739
Kurabi, Arwa; Pak, Kwang; Dang, Xitong et al. (2013) Ecrg4 attenuates the inflammatory proliferative response of mucosal epithelial cells to infection. PLoS One 8:e61394
Li, Jian-Dong; Hermansson, Ann; Ryan, Allen F et al. (2013) Panel 4: Recent advances in otitis media in molecular biology, biochemistry, genetics, and animal models. Otolaryngol Head Neck Surg 148:E52-63
Leichtle, Anke; Hernandez, Michelle; Lee, Jasmine et al. (2012) The role of DNA sensing and innate immune receptor TLR9 in otitis media. Innate Immun 18:3-13

Showing the most recent 10 out of 23 publications