DNA methylation analysis of SOCS1, SOCS3, and LINE-1 in microdissected gingival tissue

DNA methylation plays a critical role in the regulation of the transcription of the suppressors of cytokine signaling (SOCS) 1 and SOCS3, which are modulators in the inflammation. We hypothesized that the methylation status of SOCS1, SOCS3, and long interspersed nuclear element (LINE)-1 in gingival tissues previously inflamed would be similar to that found in gingival tissues without clinical inflammation in the period studied. Laser capture microdissection was performed to isolate epithelial and connective gingival tissues. The groups were comprised by ten patients without history of periodontitis and absence of clinical signs of inflammation in the gingiva during the study (healthy group) and ten patients with history of periodontitis, presenting inflammation in the gingival tissue at the first examination of the study (controlled chronic periodontitis group). The gingival biopsies from the controlled chronic periodontitis group were collected after controlling the inflammation. DNA methylation patterns were analyzed using methylation-specific high-resolution melting and combined bisulfite restriction analysis. DNA methylation levels for SOCS1 and SOCS3 did not differ between groups or tissues; likewise, no differences were observed in total LINE-1 methylation or at specific loci. At 3 months following control of inflammation in gingival tissues, the methylation profile of SOCS1, SOCS3, and LINE-1 is similar between connective and epithelial tissues from patients that were previously affected or not by chronic inflammation. Clinical results of a successful treatment are observed after inflammation control and the molecular findings illustrate local and general methylation patterns in recovering tissues toward health conditions and might help to understand events that are occurring in oral cells. (AU)