Expression of a cathelicidin antimicrobial peptide is augmented in cholesteatoma.
OBJECTIVE
Antimicrobial peptides are active defense components of innate immunity. Their importance was confirmed at epithelial surfaces as immediate barrier effectors in preventing infection. Cathelicidins are peptide antibiotics that are receiving increasing attention. Several studies have shown that overexpression of cathelicidin results in augmented protection against bacterial infection and prevention of local infection and systemic invasion of microbes. The goal of the study was to investigate whether cathelicidin is upregulated in cholesteatoma epithelium compared with normal skin.


METHODS
Twenty patients from a prospective study of cholesteatoma tissues and normal skins were enrolled in the study. The specimens were divided into two portions. One portion was used for subsequent RNA studies; the other was used for immunohistochemical staining.


METHODS
Reverse transcriptase-polymerase chain reaction was used to assess the expression levels of cathelicidin messenger RNA (mRNA) both in cholesteatoma and in normal skin. Presumptive concentration of cathelicidin mRNA and beta2-microglobulin mRNA was evaluated. Ratio of beta2-microglobulin to cathelicidin was analyzed in each group. The expressions of cathelicidin in cholesteatoma and normal skin epithelium were investigated by an immunohistochemical technique.


RESULTS
Cathelicidin mRNA in cholesteatoma epithelium was increased 5.5-fold compared with normal skin of the ear canal. In cholesteatoma epithelium, cathelicidin was located in all the layers, but in the normal skin it was expressed only in the granular and prickle cell layers.


CONCLUSIONS
Cathelicidin is augmented in cholesteatoma epithelium, and the data in the present study are in agreement with the hypothesis that cathelicidin is likely to act as a key component in the first line of defense at the surface epithelium.
Jung
Hak Hyun
HH
Department of Otolaryngology-Head and Neck Surgery, Korea University, Guro Hospital, 80 Guro-dong, Guro-gu, Seoul 152-702, Korea.
Chae
Sung Won
SW
Jung
Seol Ki
SK
Kim
Seon Tae
ST
Lee
Heung Man
HM
Hwang
Soon Jae
SJ
D000900:Anti-Bacterial Agents / Q000378:metabolism*; D018424:Cholesteatoma, Middle Ear / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D046508:Culture Techniques; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D010455:Peptides; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011446:Prospective Studies; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D001613:beta 2-Microglobulin / Q000235:genetics / Q000378:metabolism
D000900:Anti-Bacterial Agents; D018076:DNA, Complementary; D010455:Peptides; D012333:RNA, Messenger; D001613:beta 2-Microglobulin