The transcriptional landscape of the cultured murine middle ear epithelium in vitro.

Apoorva Mulay,Md Miraj K Chowdhury,Cameron T James,Lynne Bingle,Colin D Bingle

doi:10.1242/bio.056564

Abstract

ABSTRACTOtitis 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.

Highlights

Otitis media (OM), a group of inflammatory diseases of the middle ear, is the leading cause of paediatric surgery and the most frequent reason for the prescription of antibiotics (Bakaletz, 2010; Woodfield and Dugdale, 2008)
We previously showed that mouse middle ear epithelial cells undergo a process of mucociliary differentiation over a period of 14 days when cultured at the air liquid interface (ALI)
We recently described a method to differentiate primary mouse middle ear epithelial cells (mMEECs) at an air liquid interface

Summary

Introduction

Otitis media (OM), a group of inflammatory diseases of the middle ear, is the leading cause of paediatric surgery and the most frequent reason for the prescription of antibiotics (Bakaletz, 2010; Woodfield and Dugdale, 2008). It can have both acute and chronic (recurrent) presentations the consequences of which may be life-long. Over 80% of children develop at least one incidence of OM by 3 years of age and over 700 million cases occur world-wide per year (Monasta et al, 2012). The disease is a major paediatric clinical problem that produces significant morbidity and quality-of-life issues across the world, with the major burden being seen in children in developing countries (Monasta et al, 2012)

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Conclusion