Up-regulation of cathelicidin in chronic sialadenitis

Abstract

Problem: Salivary secretions play a critical role in maintaining oral health via innate host defense mechanisms and secretion of secretory IgA. One of the antimicrobial peptides, LL-37 is the only cathelicidin protein so far identified in human beings. Cathelicidins are a family of peptides thought to provide an innate defensive barrier against a variety of potential microbial pathogens. The purpose of this study was to examine the expression of cathelicidin in human salivary glands and to investigate up-regulation of cathelicidin in inflammatory conditions. Methods: Reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemical staining were performed on 20 salivary gland tissues, 10 from normal and 10 from chronic sialadenitis. Results: Cathelicidin mRNA transcripts were detected in the normal salivary gland and chronic sialadenitis. The level of cathelicidin mRNA in chronic sialadenitis was significantly increased compared with that in the normal salivary gland. cathelicidin protein was expressed in the glandular epithelium of the normal salivary gland and chronic sialadenitis. Conclusion: The results indicate that cathelicidin might play an important role in the innate host defense of human salivary glands. Significance: In the present study, we showed the localizing expression of the human cathelicidin in salivary glands and up-regulation in the inflammatory conditions. This finding suggested the physiologic importance of cathelicidin in the defense of retrograde infection. Other functions for this broadly expressed peptide and possible expression of cathelicidin in saliva need to be evaluated. Support: None reported.