title: Propionibacterium acnes-induced iNOS and COX-2 protein expression via ROS-dependent NF-κB and AP-1 activation in macrophages.
abstract: BACKGROUND
  Propionibacterium acnes (P. acnes), a gram-positive anaerobic bacterium, plays a critical role in the development of inflammatory lesion as a result of cytokines production by keratinocytes and macrophages activation. However, effect of P. acnes on iNOS/NO and COX-2/PGE2 production in macrophages is still uninvestigated.
  
  
  OBJECTIVE
  This study aimed at determining the reactive oxygen species (ROS), inducible nitric oxide (NO) synthase (iNOS)/nitric oxide (NO), and cyclooxygenase (COX)-2/prostaglandin (PG)E2 produced by macrophages upon P. acnes infection, and dissecting the mechanism of P. acnes-stimulated multiplicity of infection (MOI)-dependent increases in iNOS and COX-2 protein expressions in accordance with the elevation of NO and PGE2 production by RAW264.7 macrophages.
  
  
  METHODS
  Using an in vitro cell culture system, the effects of P. acnes on iNOS/NO, COX-2/PGE2, ROS production, ERK/JNK, and AP-1/NF-κB activation were examined via Western blotting, a flow cytometric analysis, and luciferase assay. In pharmacological studies, the ROS scavenger, N-acetyl cysteine (NAC), the NADPH oxidase inhibitor, diphenylene iodide (DPI), and mitogen-activated protein kinase (MAPK) inhibitors (U0126 and SP600125) were applied to investigate the mechanism.
  
  
  RESULTS
  We found that P. acnes exposures increased iNOS/NO and COX-2/PGE2 expression in RAW264.7, J774A.1, and peritoneal macrophages via a MOI-dependent manner. Increased ROS production, ERK/JNK protein phosphorylation, and elevated AP-1/NF-κB luciferase activity are identified in P. acnes-induced iNOS/NO and COX-2/PGE2 production. Additionally, hispolon but not its analogs, hispolon methylether or dehydroxyhispolon, showed significant inhibition of P. acnes-induced iNOS/NO and COX-2/PGE2 production, indicating an important role of OH at C5 for hispolon's inhibition of P. acnes-induced inflammatory events in macrophages.
  
  
  CONCLUSIONS
  ROS-dependent stimulation of ERK, JNK, NF-κB, and AP-1 activation contributes to P. acnes-induced iNOS/NO and COX-2/PGE2 in macrophages, and chemicals such as hispolon possessing ability to block iNOS/NO and COX-2/PGE2 production reserve potential to be further developed for treatment of the early phase of inflammation elicited by P. acnes.
authors.affiliation: Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
authors.forename: Hsiou-Hsin
authors.initials: HH
authors.lastname: Tsai
authors.forename: Woan-Rouh
authors.initials: WR
authors.lastname: Lee
authors.forename: Pai-Hua
authors.initials: PH
authors.lastname: Wang
authors.forename: Kur-Ta
authors.initials: KT
authors.lastname: Cheng
authors.forename: Yen-Chou
authors.initials: YC
authors.lastname: Chen
authors.forename: Shing-Chuan
authors.initials: SC
authors.lastname: Shen
mesh_terms: D000493:Allopurinol / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000276:immunology; D016908:Gram-Positive Bacterial Infections / Q000276:immunology / Q000378:metabolism*; D007093:Imidazoles / Q000494:pharmacology; D008156:Luciferases / Q000235:genetics; D020935:MAP Kinase Signaling System / Q000502:physiology; D008264:Macrophages / Q000201:enzymology* / Q000276:immunology / Q000382:microbiology; D051379:Mice; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D011425:Propionibacterium acnes / Q000276:immunology / Q000378:metabolism*; D011758:Pyrroles / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: C556060:6,7-dihydro-5H-pyrrolo(1,2-a)imidazole; D004791:Enzyme Inhibitors; D007093:Imidazoles; D016328:NF-kappa B; D011758:Pyrroles; D017382:Reactive Oxygen Species; D018808:Transcription Factor AP-1; D009569:Nitric Oxide; D000493:Allopurinol; D008156:Luciferases; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2; D014969:Xanthine Oxidase; D019255:NADPH Oxidases; D015232:Dinoprostone