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Introduction: Long interspersed nuclear elements (LINEs) are endogenous retrotransposable elements. A few studies have linked the methylation pattern of LINE-1 to different mental disorders (e.g., post-traumatic stress disorder [PTSD], autism spectrum disorder [ASD], panic disorder [PD]). We sought to unify the existing knowledge in the field and provide a better understanding of the association between mental disorders and LINE-1 methylation. Methods: A systematic review was executed with 12 eligible articles according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results: For psychotic disorders, PTSD, ASD, and PD, lower LINE-1 methylation levels were detected, whereas for mood disorders, the findings are controversial. The studies were conducted with subjects aged 18-80 years. Peripheral blood samples were utilized in 7/12 articles. Conclusion: Although most studies have shown that LINE-1 hypomethylation was associated with mental disorders, there were still some divergences (i.e., hypermethylation associated with mental disorders). These studies suggest that LINE-1 methylation may be an important factor related to the development of mental disorders and highlight the need to better comprehend the biological mechanisms underlying the role of LINE-1 in mental disorders pathophysiology.

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OBJECTIVES: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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 RELEVANCE: 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.

Assuntos

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OBJECTIVE: DNA methylation has been shown to be critical in the regulation of inflammatory genes. Infections are able to trigger susceptibility to disease and it can be considered as potential epimutagenic factors in reshaping the epigenome. Therefore, what would be the DNA methylation status in cells present in an infected and inflamed oral environment? The aim was to verify the DNA methylation pattern in oral epithelium cells from aggressive periodontitis (AgP) patients in a specific gene involved in the inflammation control, as suppressor of cytokine signalling (SOCS)1 and in a broader way through long interspersed nuclear element (LINE)-1. DESIGN: Genomic DNA from oral cells of 30 generalized AgP patients and 30 healthy patients were purified and modified by sodium bisulfite. DNA methylation patterns were analyzed using combined bisulfite restriction analysis (COBRA) for SOCS1 and LINE-1. RESULTS: An overall scenario of demethylation was seen for both groups, whereas the healthy group presented a higher percentage of demethylation (p<0.001), also presenting the majority of total demethylated samples (83.3% versus 70.8% in the AgP group). Total LINE-1 methylation or at each specific loci presented significant differences amongst groups. CONCLUSION: Epithelial cells, present in an infected and inflamed oral environment, show different DNA methylation status from those present in a healthy oral environment, regarding the SOCS1 and LINE-1. In addition, the investigation allows detecting alterations in the DNA in a non-limited manner, since the results observed might reflect a generalized condition of the oral epithelial cells, besides reflecting the condition of the gingival epithelium cells.

Assuntos