Abstract
A thorough understanding of the molecular details of the interactions between bacteria and host are critical to ultimately prevent disease. Recent technological advances allow simultaneous analysis of host and bacterial protein and metabolic profiles from a single small tissue sample to provide insight into pathogenesis. We used the chinchilla model of human otitis media to determine, for the first time, the most expansive delineation of global changes in protein and metabolite profiles during an experimentally induced disease. After 48 h of infection with nontypeable Haemophilus influenzae, middle ear tissue lysates were analyzed by high-resolution quantitative two-dimensional liquid chromatography-tandem mass spectrometry. Dynamic changes in 105 chinchilla proteins and 66 metabolites define the early proteomic and metabolomic signature of otitis media. Our studies indicate that establishment of disease coincides with actin morphogenesis, suppression of inflammatory mediators, and bacterial aerobic respiration. We validated the observed increase in the actin-remodeling complex, Arp2/3, and experimentally showed a role for Arp2/3 in nontypeable Haemophilus influenzae invasion. Direct inhibition of actin branch morphology altered bacterial invasion into host epithelial cells, and is supportive of our efforts to use the information gathered to modify outcomes of disease. The twenty-eight nontypeable Haemophilus influenzae proteins identified participate in carbohydrate and amino acid metabolism, redox homeostasis, and include cell wall-associated metabolic proteins. Quantitative characterization of the molecular signatures of infection will redefine our understanding of host response driven developmental changes during pathogenesis. These data represent the first comprehensive study of host protein and metabolite profiles in vivo in response to infection and show the feasibility of extensive characterization of host protein profiles during disease. Identification of novel protein targets and metabolic biomarkers will advance development of therapeutic and diagnostic options for treatment of disease.
Highlights
From the ‡The Center for Microbial Pathogenesis, The Research Institute at Nationwide Children’s Hospital, Columbus, Ohio 43205; §The Center for Microbial Interface Biology and Department of Pediatrics, The Ohio State University, Columbus, Ohio 43210; ¶Human and Molecular Genetics Center and ʈDepartment of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin 53226; **Division of Pediatric Otolaryngology, Children’s Hospital of Wisconsin, Milwaukee, Wisconsin 53226; ‡‡Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, Medical Center, Durham, North Carolina 27710
The analyses of heterogeneous cell populations limit the ability to assign specific proteins to individual cell types, the use of the entire middle ear tissue provides a unique snapshot of the complex changes and microenvironmental cues that both the host and the bacteria respond to early during infection
Similar to other studies of serum/plasma, cerebrospinal fluid, or bronchoalveolar lavage fluid (44 – 48), the middle ear exhibits a large dynamic range of protein abundance. Despite this complexity of the in vivo model system, we identified and obtained differential quantitative information for peptides derived from 377 proteins involved in such processes as: actin filament morphogenesis, inflammation, substrate binding, oxidative stress, vesicular transport as well as neutrophil associated proteins, indicating early neutrophil infiltration
Summary
Quantitative characterization of the molecular signatures of infection will redefine our understanding of host response driven developmental changes during pathogenesis. These data represent the first comprehensive study of host protein and metabolite profiles in vivo in response to infection and show the feasibility of extensive characterization of host protein profiles during disease. Proteomic and Metabolomics Signatures of Otitis Media of pathogenesis in experimental models of disease as well as in human samples. The scope of the problem is apparent with the observation that globally there are 709 million cases of AOM estimated per year of which 51% occur in children under the age of five [4]. Novel solutions are needed for this highly prevalent disease and require extensive description of the molecular mechanisms of disease to define novel therapeutic targets
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