title: Human beta-defensin-1 mRNA is transcribed in tympanic membrane and adjacent auditory canal epithelium.
abstract: The external auditory canal is less susceptible to infections than the sensitive middle-ear cavity. Since recent research has provided insight to the production of potent antimicrobial peptides from various surface epithelia, we wanted to investigate whether protection of the external auditory canal in part could be explained by the production of human beta-defensin-1 (HBD-1). This particular peptide is known to be constitutively expressed in various surface epithelia, such as airway, skin, and urogenital tissues. By reverse transcriptase PCR we demonstrate HBD-1 mRNA in the pars tensa and pars flaccida of the tympanic membrane and in the meatal skin. In situ hybridization studies localized the HBD-1 mRNA to the epidermal layer of these tissues. The HBD-1 transcripts were also evident in the sebaceous glands and in hair follicles of the meatal skin. In contrast, HBD-1 mRNA was not detected in the tympanal epithelium of the eardrum. The widespread presence of mRNA encoding for this broad-spectrum antimicrobial peptide in the meatal skin and tympanic membrane suggests that HBD-1 participates in the innate antimicrobial defense of the external auditory canal and middle-ear cavity.
authors.affiliation: Departments of Experimental Pathology, University of Tromso, Tromso, Norway. roadb@fagmed.uit.no
authors.forename: R
authors.initials: R
authors.lastname: Bøe
authors.forename: J
authors.initials: J
authors.lastname: Silvola
authors.forename: J
authors.initials: J
authors.lastname: Yang
authors.forename: U
authors.initials: U
authors.lastname: Moens
authors.forename: P B
authors.initials: PB
authors.lastname: McCray
authors.forename: L E
authors.initials: LE
authors.lastname: Stenfors
authors.forename: R
authors.initials: R
authors.lastname: Seljfelid
mesh_terms: D023082:Defensins; D004424:Ear Canal / Q000276:immunology* / Q000378:metabolism; D004848:Epithelium / Q000276:immunology; D006801:Humans; D017403:In Situ Hybridization; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012867:Skin / Q000473:pathology; D014158:Transcription, Genetic; D014432:Tympanic Membrane / Q000276:immunology* / Q000378:metabolism; D023083:beta-Defensins
chemical_list: C406407:DEFB1 protein, human; D023082:Defensins; D011506:Proteins; D012333:RNA, Messenger; D023083:beta-Defensins