title: Real-time quantitative reverse transcription-PCR analysis of expression stability of Aggregatibacter actinomycetemcomitans fimbria-associated gene in response to photodynamic therapy.
abstract: BACKGROUND
  Aggregatibacter actinomycetemcomitans is an etiological agent of both chronic and aggressive periodontitis. Dissemination of A. actinomycetemcomitans from the oral cavity and initiation of systemic infections has led to new approaches for treatment being needed. In this study, a series of experiments presented investigated the effect of methylene blue (MB)-mediated antimicrobial photodynamic therapy (aPDT) on cell viability and expression of fimbria-associated gene (rcpA) in A. actinomycetemcomitans.
  
  
  METHODS
  To determine the dose-depended effects of aPDT, A. actinomycetemcomitans ATCC 33384 strain photosensitized with MB was irradiated with diode laser following bacterial viability measurements. Cell-surviving assay and expression ratio of rcpA were assessed by colony forming unit and real-time quantitative reverse transcription-PCR (qRT-PCR) assays, respectively.
  
  
  RESULTS
  In the current study, MB-mediated aPDT using 100μg/mL showed significant reduction in A. actinomycetemcomitans growth when compared to the control (P<0.05). Sub-lethal dose of aPDT against A. actinomycetemcomitans was 25μg/mL MB at fluency of 93.75J/cm2. Sub-lethal dose of aPDT could lead to about four-fold suppression of expression of rcpA.
  
  
  CONCLUSIONS
  High doses of MB-mediated aPDT could potentially exhibit antimicrobial activity, and the expression of rcpA as an important virulence factor of this strain is reduced in cells surviving aPDT with MB. So, aPDT can be a valuable tool for the treatment of A. actinomycetemcomitans infections.
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Pourhajibagher
authors.affiliation: Laser Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Abbas
authors.initials: A
authors.lastname: Monzavi
authors.affiliation: Laser Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Nasim
authors.initials: N
authors.lastname: Chiniforush
authors.affiliation: School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Moein
authors.initials: MM
authors.lastname: Monzavi
authors.affiliation: School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Shaghayegh
authors.initials: S
authors.lastname: Sobhani
authors.affiliation: Laser Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran. Electronic address: s.shahabi.1973@gmail.com.
authors.forename: Sima
authors.initials: S
authors.lastname: Shahabi
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Laser Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran. Electronic address: abahador@tums.ac.ir.
authors.forename: Abbas
authors.initials: A
authors.lastname: Bahador
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D058491:Bacterial Load; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism; D010861:Fimbriae, Bacterial / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects* / Q000528:radiation effects*; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage; D011829:Radiation Dosage; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D016896:Treatment Outcome
chemical_list: D001425:Bacterial Outer Membrane Proteins; D015415:Biomarkers; D017319:Photosensitizing Agents; C119576:RcpA protein, Actinobacillus actinomycetemcomitans; D036781:Fimbriae Proteins
keywords: Aggregatibacter actinomycetemcomitans; Biofilm; Diode laser; Methylene blue; Photodynamic therapy; Virulence factor; qRT-PCR; rcpA