Expression of the gap junction proteins connexin 26 and connexin 43 in human middle ear cholesteatoma.
CONCLUSIONS
The results of this study showed upregulated expression and a change in localization of both connexin 43 (Cx43) and Cx26 in human middle ear cholesteatoma compared to those in normal retroauricular skins (RASs) and ear canal skins (ECSs). This suggests that perturbations of intercellular communication through gap junctions may be associated with the pathology of human cholesteatomas.


OBJECTIVE
Cholesteatomas in the middle ear require intercellular signal exchange through gap junctions as well as intracellular signal pathways for the hyperproliferation and differentiation of epithelial cells. Cx is a gap junction protein involved in intercellular communication. The objective of this study was to analyze the expression and possible roles of Cx43 and Cx26 in human cholesteatoma compared to normal epithelium.


METHODS
Ten RASs, 10 ECSs and 10 cholesteatomas were obtained during middle ear operations. Immunohistochemical staining, Western blotting and reverse transcriptase polymerase chain reaction (RT-PCR) were used to detect Cx43 and Cx26. The expression patterns of Cx43 and Cx26 were also compared with that of the proliferation marker Ki67.


RESULTS
In human cholesteatomas, Cx43 was expressed in whole suprabasal layers, except in the basal layer, and Cx26 was usually expressed in the suprabasal and basal layers. However, normal RASs showed weak expression of Cx43 in the upper spinosal and granular layers (with no expression in the basal layers) and restricted localization of Cx26 in the basal layer. The expression of Cx43 and Cx26 in ECSs was weak but showed similar patterns to that of cholesteatoma. RT-PCR and Western blotting showed that the expression of Cx43 and Cx26 was higher in cholesteatoma than in RASs. Epithelial cells expressing Cx43 and Cx26 in cholesteatoma were not exactly identical to Ki67-expressing cells on immunohistochemical staining.
Choung
Yun-Hoon
YH
Department of Otolaryngology, Ajou University School of Medicine, Suwon, South Korea. yhc@ajou.ac.kr
Park
Keehyun
K
Kang
Sung-Ook
SO
Markov Raynov
Alexander
A
Ho Kim
Chul
C
Choung
Pill-Hoon
PH
D015153:Blotting, Western; D018424:Cholesteatoma, Middle Ear / Q000378:metabolism*; D000072259:Connexin 26; D018031:Connexin 43 / Q000096:biosynthesis* / Q000502:physiology; D017630:Connexins / Q000096:biosynthesis* / Q000502:physiology; D004424:Ear Canal / Q000378:metabolism; D004431:Ear, External / Q000378:metabolism; D004432:Ear, Middle / Q000473:pathology*; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
D018031:Connexin 43; D017630:Connexins; C000607042:GJB2 protein, human; D012333:RNA, Messenger; D000072259:Connexin 26