Global and gene-specific DNA methylation and hydroxymethylation in human skin exposed and not exposed to sun radiation

Abstract

Backgroundepigenomes can be influenced by environmental factors leading to the development of diseases.ObjectiveTo investigate the influence of sun exposure on global DNA methylation and hydroxymethylation status and at specific sites of the miR-9-1, miR-9-3 and MTHFR genes in skin samples of subjects with no history of skin diseases.MethodsSkin samples were obtained by punch on sun-exposed and sun-protected arm areas from 24 corpses of 16-89 years of age. Genomic DNA was extracted from skin samples that were ranked according to Fitzpatrick's criteria as light, moderate, and dark brown. Global DNA methylation and hydroxymethylation and DNA methylation analyses at specific sites were performed using ELISA and MSP, respectively.ResultsNo significant differences in global DNA methylation and hydroxymethylation levels were found among the skin areas, skin types, or age. However, gender-related differences were detected, where women showed higher methylation levels. Global DNA methylation levels were higher than hydroxymethylation levels, and the levels of these DNA modifications correlated in skin tissue. For specific sites, no differences among the areas were detected. Additional analyses showed no differences in the methylation status when age, gender, and skin type were considered; however, the methylation status of the miR-9-1 gene seems to be gender related.Study limitationsthere was no separation of dermis and epidermis and low sample size.Conclusionsun exposure does not induce changes in the DNA methylation and hydroxymethylation status or in miR-9-1, miR-9-3 and MTHFR genes for the studied skin types.

Balance between Health Risks and Benefits for Outdoor Workers Exposed to Solar Radiation: An Overview on the Role of Near Infrared Radiation Alone and in Combination with Other Solar Spectral Bands

“…Another research need is to explore epigenetic changes in cells of skin and eye tissues due to exposure to IRA (alone and combined with the rest of SR): this would lead to a better understanding of the action mechanisms and, in perspective, should be useful for risk assessment purposes. Studies in this regard are still lacking or are very scarce [115]. Finally, it should be noted that, similarly to what occurs in many other research fields, the introduction of "omics" approaches in both in vitro and in vivo studies can no longer be postponed.…”

“…be useful for risk assessment purposes. Studies in this regard are still lacking or are very scarce [115]. Finally, it should be noted that, similarly to what occurs in many other research fields, the introduction of "omics" approaches in both in vitro and in vivo studies can no longer be postponed.…”

DNA Methylation and Hydroxymethylation in Cervical Cancer: Diagnosis, Prognosis and Treatment

“…The Ten-eleven translocation (TET) family oxidize 5-mC to 5-hydroxymethylcytosine (5-hmC) that is further oxidized to 5-formylcytosine and 5-carboxylcytosine. Finally, using thymine-DNA glycosylase (TDG), the carboxyl group from 5formylcytosine and 5-carboxylcytosine are removed to restore unmethylated cytosine pool (Figure 1; Silva et al, 2017;Jayanthi et al, 2018;Zhu et al, 2018). 5-hmC is an intermediate throughout the process (Li et al, 2016).…”

UV Radiation and Its Relation to DNA Methylation in Epidermal Cells: A Review

“…In all studies, compounds used topically on the animals' skins were able to inhibit the unwanted profile (when applied alongside with UV irradiation) [42] or revert to the desired DNA methylation profile (when applied after the irradiation by UV light) [44,46]. Table 3 shows data from studies with human skin samples, and in most of these studies, the studied radiation was natural (solar) [47,[49][50][51]. In these cases, it is not possible to measure the level of exposure for volunteers precisely, and samples were collected from areas exposed and not exposed to the sun, such as the inner and outer regions of the arm.…”