title: Protease-activated receptor-2 mediates the expression of inflammatory cytokines, antimicrobial peptides, and matrix metalloproteinases in keratinocytes in response to Propionibacterium acnes.
abstract: Propionibacterium acnes (P. acnes) has been known to produce various exogenous proteases, however, their role in acne pathogenesis remains largely unknown. Proteases elicit cellular responses, at least in part, via proteinase-activated receptor-2 (PAR-2), which is known to mediate inflammation and immune response. In this study, we investigated whether proteases from P. acnes could activate PAR-2 on keratinocytes and induce pro-inflammatory cytokines, antimicrobial peptides (AMPs), and matrix metalloproteinases (MMPs) via PAR-2 signaling. We examined PAR-2 expression and protease activity in acne lesions using immunofluorescence staining and in situ zymography. The effect of the culture supernatant of P. acnes on Ca(2+) signaling in immortalized keratinocytes (HaCaT) was measured using a fluorescence method. HaCaT cells were treated with P. acnes strain ATCC 6919 culture supernatant, with or without pretreatment with serine protease inhibitor or selective PAR-2 antagonist and the gene expression of pro-inflammatory cytokines, AMPs, and MMPs was detected using real-time reverse transcription-polymerase chain reaction. We found that the protease activity and PAR-2 expression were increased in acne lesions. The P. acnes culture supernatant induced calcium signaling in keratinocytes via PAR-2 and stimulated the mRNA expression of interleukin (IL)-1α, -8, tumor necrosis factor (TNF)-α, human beta defensin (hBD)-2, LL-37, MMP-1, -2, -3, -9, and -13 in keratinocytes, which was significantly inhibited by serine protease inhibitor as well as selective PAR-2 specific antagonist. These results indicate that PAR-2 plays an important role in the pathogenesis of acne by inducing inflammatory mediators in response to proteases secreted from P. acnes.
authors.affiliation: Department of Dermatology, Gangnam Severance Hospital, Yonsei University College of Medicine, 712 Eonjuro, Kangnam-gu, Seoul 135-720, Korea.
authors.forename: Sang Eun
authors.initials: SE
authors.lastname: Lee
authors.forename: Ji-Min
authors.initials: JM
authors.lastname: Kim
authors.forename: Se Kyoo
authors.initials: SK
authors.lastname: Jeong
authors.forename: Jeong Eun
authors.initials: JE
authors.lastname: Jeon
authors.forename: Hyun-Ju
authors.initials: HJ
authors.lastname: Yoon
authors.forename: Min-Kyung
authors.initials: MK
authors.lastname: Jeong
authors.forename: Seung Hun
authors.initials: SH
authors.lastname: Lee
mesh_terms: D000152:Acne Vulgaris / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000276:immunology; D002461:Cell Line, Transformed; D016207:Cytokines / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology; D016908:Gram-Positive Bacterial Infections / Q000276:immunology*; D006801:Humans; D018836:Inflammation Mediators / Q000276:immunology / Q000378:metabolism; D015603:Keratinocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D020782:Matrix Metalloproteinases / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D011425:Propionibacterium acnes / Q000276:immunology*; D044464:Receptor, PAR-2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology
chemical_list: D000942:Antigens, Bacterial; D023181:Antimicrobial Cationic Peptides; D016207:Cytokines; D018836:Inflammation Mediators; D044464:Receptor, PAR-2; D015842:Serine Proteinase Inhibitors; D020782:Matrix Metalloproteinases