Differential Protein Expression in Congenital and Acquired Cholesteatomas

PLoS One. 2015 Sep 3;10(9):e0137011. doi: 10.1371/journal.pone.0137011. eCollection 2015.

Abstract

Congenital cholesteatomas are epithelial lesions that present as an epithelial pearl behind an intact eardrum. Congenital and acquired cholesteatomas progress quite differently from each other and progress patterns can provide clues about the unique origin and pathogenesis of the abnormality. However, the exact pathogenic mechanisms by which cholesteatomas develop remain unknown. In this study, key proteins that directly affect cholesteatoma pathogenesis are investigated with proteomics and immunohistochemistry. Congenital cholesteatoma matrices and retroauricular skin were harvested during surgery in 4 patients diagnosed with a congenital cholesteatoma. Tissue was also harvested from the retraction pocket in an additional 2 patients during middle ear surgery. We performed 2-dimensional (2D) electrophoresis to detect and analyze spots that are expressed only in congenital cholesteatoma and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/MS) to separate proteins by molecular weight. Protein expression was confirmed by immunohistochemical staining. The image analysis of 2D electrophoresis showed that 4 congenital cholesteatoma samples had very similar protein expression patterns and that 127 spots were exclusively expressed in congenital cholesteatomas. Of these 127 spots, 10 major spots revealed the presence of titin, forkhead transcription activator homolog (FKH 5-3), plectin 1, keratin 10, and leucine zipper protein 5 by MALDI-TOF/MS analysis. Immunohistochemical staining showed that FKH 5-3 and titin were expressed in congenital cholesteatoma matrices, but not in acquired cholesteatomas. Our study shows that protein expression patterns are completely different in congenital cholesteatomas, acquired cholesteatomas, and skin. Moreover, non-epithelial proteins, including FKH 5-3 and titin, were unexpectedly expressed in congenital cholesteatoma tissue. Our data indicates that congenital cholesteatoma origins may differ from those of acquired cholesteatomas, which originate from retraction pocket epithelia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Child, Preschool
  • Cholesteatoma / congenital*
  • Cholesteatoma / metabolism*
  • Cholesteatoma / pathology
  • Connectin / metabolism
  • Female
  • Forkhead Transcription Factors / metabolism
  • Humans
  • Male
  • Middle Aged
  • Proteomics
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Substances

  • Connectin
  • Forkhead Transcription Factors

Supplementary concepts

  • Cholesteatoma, Congenital

Grants and funding

This research was supported by the Bio & Medical Technology Development Program of the National Research Foundation (NRF) funded by the Ministry of Science, ICT & Future Planning (2013M3A9D5072551) and Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education, Science and Technology (grant number) R11-2007-040-02001-0. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.