Epigenetics, DNA Methylation Patterns and Periodontal Disease
Condition: Periodontal Disease
MeSH terms: Periodontal Diseases
Study type: Observational

Summary: 
      The overall goal of this research is (1) to identify changes in gene expression and DNA
      methylation status in subjects who exhibit advanced chronic periodontal inflammation and (2)
      to identify microRNAs (miRNAs) and the interactive pathways associated with obesity as a
      modifier of periodontal infection pathogenesis.
    

Detailed description: 
      Aim 1. To determine whether diseased periodontal tissues biopsied from patients with
      periodontal disease will have altered DNA methylation patterns of selected genes as compared
      to the DNA methylation status biopsies obtained from adjacent, non-diseased periodontal
      sites, as well as periodontal biopsy samples obtained from non-diseased, healthy subjects.

      Aim 2. To determine the role of tissue DNA Methylation on mRNA expression:

        -  2a. To determine whether alterations in tissue mRNA expression (as determined by
           quantitative PCR) are associated with an aberrant DNA methylation status of respective
           gene promoter CpG islands in tissue biopsy samples obtained from diseased and
           non-diseased tissues from patients with periodontal disease and from non-diseased
           healthy subjects.

        -  2b. By performing laser capture microdissection of biopsy samples from diseased patients
           [(epithelium, connective tissue and inflammatory infiltrate)] we seek to determine
           cellular patterns of mRNA expression and DNA methylation of targeted genes comparing
           inflamed to non-inflamed sites within diseased patients.

        -  2c. We will perform in vitro studies to analyze whether gingival fibroblasts from
           patients with periodontal disease will show a differential methylation pattern and
           whether these cells will display a differential inflammatory response when compared to
           control fibroblasts isolated from healthy subjects.

      Aim 3. The aim of this pilot investigation was to determine if miRNA expression differed in
      the presence or absence of obesity, comparing gingival biopsies obtained from patients with
      or without periodontal disease.

        -  3a. To determine whether diseased periodontal tissues biopsied from patients with
           periodontal disease will influence the level of miRNA expression as compared to the
           biopsies obtained from non-diseased, healthy subjects.

        -  3b. To determine whether BMI [nonobese subjects BMI <30kg/m2, obese subjects >30kg/m2]
           will influence the level of miRNA expression in biopsies from diseased periodontal
           tissues as compared to periodontal biopsy samples obtained from non-diseased, healthy
           subjects.

      Gingival samples, gingival crevicular fluid, saliva and plaque samples will be collected and
      a periodontal examination will be performed. The periodontal assessment will record pocket
      depth, clinical attachment level and percent bleeding on probing. Blood pressure, height and
      weight (Body Mass Index assessment) will be obtained on participants as well.

      Tissue gene expression by quantitative PCR and DNA methylation sequence analysis, proteomic
      analyses of gingival crevicular fluid, Differential Methylation Hybridization and, microRNA
      expression profile by Human miRNA Microarray and Real-time PCR quantification will all be
      performed.
    

Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Probability Sample
Study population: 
        Ninety-eight subjects will be recruited from the Graduate Periodontics Clinic and Dental
        Faculty Practice at the University of North Carolina School of Dentistry and if needed from
        the general population. Subjects must present with either chronic periodontitis or
        periodontal health.
      
Biospecimen description: 
      -  Gingiva biopsy samples (epithelium, connective tissue)

        -  Gingival crevicular fluid

        -  Saliva

        -  Plaque samples
    
Keywords: Epigenomics; DNA methylation; MicroRNA; Periodontitis; Inflammation; Obesity