title: Sex-based differential regulation of bacterial-induced bone resorption.
abstract: OBJECTIVE
  Periodontal disease pathogenesis is comprised of the complex inflammatory immune response to oral bacterial dysbiosis. Like other inflammatory diseases, there is sexual dimorphism evident in periodontal diseases. During periodontitis, inflammatory chemokines direct neutrophils to migrate to the site of infection to neutralize the pathogen. Interestingly, these same chemokines are also involved in regulating pathogen-induced osteoclast formation. Previous reports show differences in bone turnover and lymphocyte recruitment between sexes. We hypothesize that chemokine expression is differentially regulated by sex and thus results in differential osteoclast formation.
  
  
  METHODS
  Male and female mice were utilized to isolate neutrophils based on expression of Ly6G-specific, as well as defined osteoclast progenitors. Cells were stimulated with lipopolysaccharide (LPS; 100 ng/mL) then analyzed for neutrophil infiltration and gene expression. Defined osteoclast progenitors were primed: macrophage-colony stimulating factor (25 ng/mL), receptor activator of NF-κB ligand (50 ng/mL), then stimulated with LPS. Osteoclasts were enumerated via TRAP stain and mRNA isolated for gene expression analysis via quantitative polymerase chain reaction.
  
  
  RESULTS
  In response to LPS, male neutrophils in vitro respond with increased chemokine expression and significantly more osteoclast formed in response to LPS compared to females.
  
  
  CONCLUSIONS
  Findings support observations in humans regarding a sexual dimorphism in oral bacterial infections of alveolar bone loss. Males have a strong inflammatory response to bacterial infection, resulting in increased inflammatory microenvironment, reduced pathogenic bacteria clearance and increased osteoclast-driven bone loss in response to differential expression of key chemokines.
authors: Department of Oral Health Sciences, The Center for Oral Health Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors: M S
authors: MS
authors: Valerio
authors: Department of Oral Health Sciences, The Center for Oral Health Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors: D S
authors: DS
authors: Basilakos
authors: Department of Oral Health Sciences, The Center for Oral Health Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors: J E
authors: JE
authors: Kirkpatrick
authors: Department of Oral Health Sciences, The Center for Oral Health Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors: M
authors: M
authors: Chavez
authors: Department of Oral Health Sciences, The Center for Oral Health Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors: J
authors: J
authors: Hathaway-Schrader
authors: Department of Oral Health Sciences, The Center for Oral Health Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors: B A
authors: BA
authors: Herbert
authors: Department of Oral Health Sciences, The Center for Oral Health Sciences, Medical University of South Carolina, Charleston, SC, USA.|Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA.
authors: K L
authors: KL
authors: Kirkwood
mesh_terms: D000818:Animals; D001862:Bone Resorption / Q000382:microbiology* / Q000503:physiopathology; D018925:Chemokines / Q000378:metabolism; D005260:Female; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D051379:Mice; D009504:Neutrophils / Q000502:physiology; D010010:Osteoclasts / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012737:Sex Factors
chemical_list: D018925:Chemokines; D008070:Lipopolysaccharides
keywords: chemokines; neutrophils; oral infections; osteoclastogenesis