Demodex-associated bacterial proteins induce neutrophil activation.
AffiliationMedical Mycology Unit, Department of Biology, National University of Ireland, Maynooth, Co. Kildare, Ireland. Respiratory Research Division, Department of, Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9,, Ireland.
MetadataShow full item record
CitationBr J Dermatol. 2011 Nov 19. doi: 10.1111/j.1365-2133.2011.10746.x.
JournalThe British journal of dermatology
AbstractBackground: Patients with rosacea demonstrate a higher density of Demodex mites in their skin than controls. A bacterium isolated from a Demodex mite from a patient with papulopustular rosacea (PPR) was previously shown to provoke an immune response in patients with PPR or ocular rosacea thus suggesting a possible role for bacterial proteins in the etiology of this condition. Objectives: To examine the response of neutrophils to proteins derived from a bacterium isolated from a Demodex mite. Methods: Bacterial cells were lysed and proteins were partially purified by AKTA-FPLC. Isolated neutrophils were exposed to bacterial proteins and monitored for alterations in migration, degranulation and cytokine production. Results: Neutrophils exposed to proteins from Bacillus cells demonstrated increased levels of migration and elevated release of MMP-9, an enzyme known to degrade collagen and cathelicidin, an antimicrobial peptide. In addition neutrophils exposed to the bacterial proteins demonstrated elevated rates of Il-8 and TNF-alpha production. Conclusions: Proteins produced by a bacterium isolated from a Demodex mite have the ability to increase the migration, degranulation and cytokine production abilities of neutrophils. These results suggest that bacteria may play a role in the inflammatory erythema associated with rosacea.