Expression of bone morphogenetic protein-2 messenger ribonucleic acid in cholesteatoma fibroblasts.
OBJECTIVE
The aim of the study was to evaluate the role of bone morphogenetic protein-2 (BMP-2) in the pathology of middle ear cholesteatoma.


BACKGROUND
Middle ear cholesteatoma is a chronic inflammatory disease associated with destruction of the temporal bone and marked by increased expression levels of diverse cytokines. Bone remodeling associated with this disease is mainly caused by the action of osteoclasts. It has been shown that BMP-2 expression is inducible by interleukin 1 in synovial fibroblasts and that BMP-2 in combination with interleukin 1alpha is able to stimulate the formation of osteoclast-like multinucleated cells in co-cultures of osteoblast-like cells and hematopoietic cells.


METHODS
By using Northern hybridizations, we examined the messenger ribonucleic acid expression of BMP-2 in keratinocytes and fibroblasts derived from normal external ear canal skin (EACS) and from cholesteatoma, respectively.


RESULTS
We show that normal EACS fibroblasts do not express BMP-2, whereas keratinocytes of both EACS and cholesteatoma origin are positive for the BMP-2 transcript. In contrast to EACS fibroblasts, BMP-2 is clearly expressed in cholesteatoma perimatrix fibroblasts. Incubation of normal fibroblasts with cholesteatoma extracts caused the transcription of BMP-2. Interleukin 1alpha, bacterial endotoxin, or bovine keratin, however, were not able to initiate BMP-2 expression in normal fibroblasts.


CONCLUSIONS
In view of the above data, it is tempting to speculate that BMP-2 expression might play a role in cholesteatoma pathology.
Schmidt
Marianne
M
Department of Otorhinolaryngology, University of Würzburg, Josef-Schneider-Strasse 11, D-97080 Würzburg, Germany. marianne.schmidt@mail.uni-wuerzburg.de
Schler
Gabriele
G
Gruensfelder
Petra
P
Hoppe
Florian
F
D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000235:genetics*; D002478:Cells, Cultured; D018424:Cholesteatoma, Middle Ear / Q000378:metabolism* / Q000473:pathology; D004424:Ear Canal / Q000378:metabolism / Q000473:pathology; D004431:Ear, External; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D012867:Skin / Q000378:metabolism / Q000473:pathology; D013997:Time Factors; D014020:Tissue Extracts / Q000494:pharmacology; D016212:Transforming Growth Factor beta
C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D012333:RNA, Messenger; D014020:Tissue Extracts; D016212:Transforming Growth Factor beta