Project description:Middle ear epithelium (MEE) is an extended part of the respiratory mucosa and mucociliary differentiation of MEE is crucial for the maintenance of homeostasis and sterility of the middle ear cavity. Previously we developed an in vitro model of murine MEE using air-liquid interface (ALI) culture that replicates aspects of the in vivo middle ear. Defects in MEE function can lead to the development of otitis media (OM). Decoding differential gene expression (DGE) across the MEE during mucociliary differentiation is valuable in understanding the mechanism underpinning the development of OM. We used ClariomTM S Mouse assay to understand the global gene expression at different time points of murine MEE differentiation at ALI culture and to identify sets of genes up-regulated and down-regulated during this process.
Project description:Objective: Otitis media is known to alter expression of cytokine and other genes in the mouse middle ear and inner ear. However, whole mouse genome studies of gene expression in otitis media have not previously been undertaken. Ninety-nine percent of mouse genes are shared in the human, so these studies are relevant to the human condition. Methods: To assess inflammation-driven processes in the mouse ear, gene chip analyses were conducted on mice treated with trans-tympanic heat-killed Hemophilus influenza using untreated mice as controls. Middle and inner ear tissues were separately harvested at 6 hours, RNA extracted, and samples for each treatment processed on the Affymetrix 430 2.0 Gene Chip for expression of its 34,000 genes. Results: Statistical analysis of gene expression compared to control mice showed significant alteration of gene expression in 2,355 genes, 11% of the genes tested and 8% of the mouse genome. Significant middle and inner ear upregulation (fold change >1.5, p<0.05) was seen in 1,081 and 599 genes respectively. Significant middle and inner ear downregulation (fold change <0.67, p<0.05) was seen in 978 and 287 genes respectively. While otitis media is widely believed to be an exclusively middle ear process with little impact on the inner ear, the inner ear changes noted in this study were numerous and discrete from the middle ear responses. This suggests that the inner ear does indeed respond to otitis media and that its response is a distinctive process. Numerous new genes, previously not studied, are found to be affected by inflammation in the ear. Conclusion: Whole genome analysis via gene chip allows simultaneous examination of expression of hundreds of gene families influenced by inflammation in the middle ear. Discovery of new gene families affected by inflammation may lead to new approaches to the study and treatment of otitis media. There are 8 control samples and 9 samples trans-tympanically injected with H flu 10e9 for 6 hours. Each sample is from a single animal.
Project description:Otitis media (OM) is the most common paediatric disease and leads to significant morbidity. Although understanding of underlying disease mechanisms is hampered by complex pathophysiology, it is clear that epithelial abnormalities underpin the disease. The mechanisms underpinning epithelial remodelling in OM remain unclear. We recently described a novel in vitro model of mouse middle ear epithelial cells (mMEECs) that undergoes mucociliary differentiation into the varied epithelial cell populations seen in the middle ear cavity. We now describe genome wide gene expression profiles of mMEECs as they undergo differentiation. We compared the gene expression profiles of original (uncultured) middle ear cells, confluent cultures of undifferentiated cells and cells that had been differentiated for 7 days at an air liquid interface (ALI). >5000 genes were differentially expressed among the three groups of cells. Approximately 4000 genes were differentially expressed between the original cells and day 0 of ALI culture. The original cell population was shown to contain a mix of cell types, including contaminating inflammatory cells that were lost on culture. Approximately 500 genes were upregulated during ALI induced differentiation. These included some secretory genes and some enzymes but most were associated with the process of ciliogenesis. The data suggest that the in vitro model of differentiated murine middle ear epithelium exhibits a transcriptional profile consistent with the mucociliary epithelium seen within the middle ear. Knowledge of the transcriptional landscape of this epithelium will provide a basis for understanding the phenotypic changes seen in murine models of OM.
Project description:Objective: Otitis media is known to alter expression of cytokine and other genes in the mouse middle ear and inner ear. However, whole mouse genome studies of gene expression in otitis media have not previously been undertaken. Ninety-nine percent of mouse genes are shared in the human, so these studies are relevant to the human condition. Methods: To assess inflammation-driven processes in the mouse ear, gene chip analyses were conducted on mice treated with trans-tympanic heat-killed Hemophilus influenza using untreated mice as controls. Middle and inner ear tissues were separately harvested at 6 hours, RNA extracted, and samples for each treatment processed on the Affymetrix 430 2.0 Gene Chip for expression of its 34,000 genes. Results: Statistical analysis of gene expression compared to control mice showed significant alteration of gene expression in 2,355 genes, 11% of the genes tested and 8% of the mouse genome. Significant middle and inner ear upregulation (fold change >1.5, p<0.05) was seen in 1,081 and 599 genes respectively. Significant middle and inner ear downregulation (fold change <0.67, p<0.05) was seen in 978 and 287 genes respectively. While otitis media is widely believed to be an exclusively middle ear process with little impact on the inner ear, the inner ear changes noted in this study were numerous and discrete from the middle ear responses. This suggests that the inner ear does indeed respond to otitis media and that its response is a distinctive process. Numerous new genes, previously not studied, are found to be affected by inflammation in the ear. Conclusion: Whole genome analysis via gene chip allows simultaneous examination of expression of hundreds of gene families influenced by inflammation in the middle ear. Discovery of new gene families affected by inflammation may lead to new approaches to the study and treatment of otitis media.
Project description:* Bone signaling in middle ear development * <br/>Common middle ear diseases, such as chronic suppurative otitis media and cholesteatoma, may affect bone behavior in the middle ear air cell system. <br/> This study analyzed gene expression of bone-related signaling factors and gene sets from lining tissues in the developing middle ear of the rat. Candidate gene products were compared with previously published data on middle ear bone metabolism. <br/> Microarray technology was used to identify bone-related genes and gene sets, which were differentially expressed between the adult (quiescent) bulla and young (resorbing/forming) bulla. <br/><br/> * Gene expression of the otic capsule *<br/>The behavior of bone cells within the otic capsule is unique. After occification localized bone remodeling is virtually absent. Human otosclerosis is a localized disease within the otic capsule where the bone starts to remodel pathologically. Disease etiology is unknown and the pathogenesis is only partially elucidated.<br/><br/> The objective of this study is to measure bone-related gene expression of the otic capsule in order to reveal additionally signaling factors responsible for the absent bone remodeling within the otic capsule.<br/><br/> Microarray technology was used to determine genes involved in the bone metabolism, which were differentially expressed between lining tissues from the otic capsule and lining tissues from the middle ear of the rat.
Project description:Chronic Otitis Media (OM) develops after sustained inflammation and is characterized by secretory middle ear epithelial metaplasia and effusion, most frequently mucoid. Non-typeable Haemophilus influenzae (NTHi), the most common acute OM pathogen, is known to activate inflammation and mucin expression in vitro and in animal models of OM. The goals of this study were to: examine expression profiling epithelial effects of NTHi challenge in murine middle ears. We used microarrays to detail examine the global programme of gene expression underlying epithelial effects of NTHi challenge in murine middle ears during this study. Weekly transtympanic inoculation of Balb/c mice with 300 µg/ml of NTHi lysates vs saline was performed. Bacteria were grown on chocolate agar at 37ºC in 5% CO2 overnight and inoculated in brain heart infusion (BHI) broth supplemented with 3.5 mg of nicotinamide adenine dinucleotide per ml. After overnight incubation, bacteria were subcultured into 5 ml of fresh brain heart infusion (BHI) and upon reaching log phase growth, NTHi were washed and suspended in phosphate-buffered saline (PBS) followed by sonication for lysis. Three transtympanic inoculation of 6 Balb/c mice middle ears (3 animals, 6 ears) with 50 uL of 300 ug/ml of NTHi bacterial lysate and 6 Balb/c mice middle ears (3 animals, 6 ears) with 50 uL of 1X phosphate buffered saline (PBS) were carried out weekly over 4 weeks (injection on days 7, 14, and 21). On day 28, the mice were euthanized and their bullae harvested. Expression microarray analysis was performed at 1 and 7 days. Microarray findings were validated in independent animal samples and in a cultured murine middle ear epithelial cell (mMEEC) line.
Project description:Chronic Otitis Media (OM) develops after sustained inflammation and is characterized by secretory middle ear epithelial metaplasia and effusion, most frequently mucoid. Non-typeable Haemophilus influenzae (NTHi), the most common acute OM pathogen, is known to activate inflammation and mucin expression in vitro and in animal models of OM. The goals of this study were to: examine expression profiling epithelial effects of NTHi challenge in murine middle ears. We used microarrays to detail examine the global programme of gene expression underlying epithelial effects of NTHi challenge in murine middle ears during this study.
Project description:Single-cell transcriptomics were used to identify cells in the normal middle ear mucosa, to identify their differentially expressed genes, and to determine cell-type-specific expression of genes related to innate immunity .
Project description:Background: Air-pollutants containing toxic particulate matters (PM) deposit in the respiratory tract and increases microbial infections. However, the mechanism underline is not well understood. In this study, we evaluated the effect of urban particles (UP) on S. pneumoniae in-vitro biofilm formation, colonization on Human middle ear epithelium cells (HMEECs) and in mouse nasal cavity and transition to middle ear and lungs. Methods: S. pneumoniae in vitro biofilms and planktonic growth was evaluated in metal ion free medium in presence of UP, and biofilms were quantified by CV-microplate assay, cfu counts and resazurin staining. Biofilm structures were analyzed using scanning electron microscope (SEM) and confocal microscopy (CM). Gene expressions of biofilms were evaluated using real time RT-PCR. Effects of UP exposure on S. pneumoniae colonization to HMEECs was evaluated using fluorescent in-situ hybridization (FISH), cell viability was detected by EZcyto kit, apoptosis in HMEECs were evaluated using Annexin-V/PI based cytometry analysis and reactive oxygen species (ROS) production were evaluated using Oxiselect kit. Alteration of HMEECs gene expressions on UP exposure or pneumococci colonization were evaluated using microarray. In vivo colonization of pneumococci in presence of UP and transition to middle ear and lungs were evaluated using intranasal mice colonization model. Results: UP exposure significantly (*p< 0.05) increased pneumococcal in vitro biofilms and planktonic growth. In presence of UP pneumococci formed organized biofilms with matrix, while in absence of UP bacteria was unable to form biofilms. The luxS, ply, lytA, comA, comB and ciaR genes involved in bacterial pathogenesis, biofilms formation and quorum sensing were up-regulated in pneumococci biofilms grown in presence of UP. The HMEECs viability was significantly (p<0.05) decreased and bacteria colonization was significantly (p<0.05) elevated in co-treatment (UP+S. pneumoniae) in compare to single treatment. Similarly, increased apoptosis and ROS produce were detected in HMEECs treated with UP+ pneumococci. The microarray analysis of HMEECs revealed that the genes involve in apoptosis and cell death, inflammation, immune response were up-regulated in co-treatment, those genes were unchanged or expressed in less fold in single treatments of UP or S. pneumoniae. In vivo study showed increased pneumococcal colonization to nasal cavity in presence of UP and higher transition of bacteria to middle ear and lungs in presence of UP.