cytidylyl-3--5--guanosine and Arthritis--Rheumatoid

Over-expression of tumor necrosis factor-alpha (TNF-α) plays a pathological role in chronic periodontitis (CP) and rheumatoid arthritis (RA), which might be regulated by the epigenetic mechanism. The aim of the present study was to evaluate whether there is a unique methylation profile of the TNF-α gene promoter in blood cells of individuals with CP and RA.. The study participants consisted of 30 Japanese adults with RA (RA group), 30 race-matched adults with CP only (CP group) and 30 race-matched healthy controls (H group). Genomic DNA isolated from peripheral blood was modified by sodium bisulfite and analyzed, by direct sequencing, to investigate DNA methylation of the TNF-α gene promoter region. The level of TNF-α produced in mononuclear cells stimulated with Porphyromonas gingivalis lipopolysaccharide was determined using ELISA.. Twelve cytosine-guanine dinucleotide (CpG) motifs were identified in the TNF-α promoter fragment from -343 to +57 bp. The CP group showed a significantly higher methylation rate and frequency at -72 bp than the H group (p < 0.01). The RA group exhibited significantly higher methylation rates at seven CpG motifs (-302, -163, -119, -72, -49, -38 and +10 bp), and significantly higher methylation frequencies at six CpG motifs (-163, -119, -72, -49, -38 and +10 bp), than the H group (p < 0.01 for all comparisons). The levels of TNF-α produced were significantly different between individuals with and without methylation at -163 bp (p = 0.03).. These results suggest that the hypermethylated status of CpG motifs in the TNF-α gene promoter in blood cells may be unique to Japanese adults with CP and RA.

Topics: Aged; Arthritis, Rheumatoid; Base Sequence; Chronic Periodontitis; Dinucleoside Phosphates; DNA Methylation; Female; Genetic Predisposition to Disease; Humans; Immunoglobulin G; Japan; Leukocytes, Mononuclear; Lipopolysaccharides; Male; Middle Aged; Nucleotide Motifs; Periodontal Attachment Loss; Periodontal Pocket; Porphyromonas gingivalis; Promoter Regions, Genetic; Tumor Necrosis Factor-alpha

Fragments from the transcribed region of the ribosomal repeat include considerable amounts of unmethylated CpG DNA motifs. These motifs activate immune cells via the interaction with Toll receptors. In vitro experiments confirmed the stimulatory effect of transcribed region of ribosomal repeat on human lymphocytes. Culturing of lymphocytes in a medium containing 2-20,000 ng/ml fragments from transcribed region of ribosomal repeat was accompanied by structural changes in the nucleus in a considerable number of cells. These changes manifested in translocation of pericentromeric heterochromatin from the membrane to the center of the nucleus and activation of the nucleolus and were accompanied by a significant increase in interleukin-6 production and slight stimulation of tumor necrosis factor-a synthesis. The transcribed region of the ribosomal repeat and E. coli DNA had various effects on quantitative parameters of lymphocytes. Our results suggest the existence of mechanisms of stimulation not mediated by the interaction of CpG DNA motifs with Toll receptors.

Topics: Arthritis, Rheumatoid; Dinucleoside Phosphates; DNA; Humans; Interleukin-6; Lymphocytes; Reference Values; Ribosomes; Transcription, Genetic; Tumor Necrosis Factor-alpha