title: The influence of sun exposure on the DNA methylation status of MMP9, miR-137, KRT14 and KRT19 genes in human skin.
abstract: BACKGROUND
  Studies have shown that a variety of environmental factors and habits are associated with epigenetic changes. In addition, various genes are also found to respond to UV radiation.
  
  
  OBJECTIVE
  The aim of this study was to investigate the sun exposure influence on the DNA methylation profile on the matrix metalloprotease-9 (MMP9), microRNA 137 (miR-137), cytokeratin 14 (KRT14) and 19 (KRT19) genes of skin cells of subjects with no history of skin diseases.
  
  
  METHODS
  Skin biopsies (5mm) were obtained using a punch technique on sun-exposed (outer forearm) and sun-protected areas (inner arm) from 30 corpses from the Brazilian Service of Death Investigation. Skin types were ranked according to Fitzpatrick's criteria. Genomic DNA was extracted and a DNA methylation analysis was performed using Methylation Specific PCR (MSP) or Methylation-Sensitive Restriction Enzymes (MSRE) of sun-exposed and sun-protected skin areas.
  
  
  RESULTS
  No differences were found among the areas (p>0.05; McNemar), with the partially methylated condition found to be a common event in skin for both MMP9 and miR-137 genes and the methylated condition for both KRT14 and KRT19 genes. Additional analysis showed no differences in the methylation status when age, gender and skin type were considered, however, the methylation status of miR-137 gene seems to be gender-related.
  
  
  CONCLUSIONS
  We conclude that sun exposure does not induce changes in the DNA methylation status in MMP9, miR-137, KRT14 and KRT19 genes.
authors.affiliation: Programa de Pós Graduação em Biologia Celular e Molecular.
authors.forename: Alanne Rayssa
authors.initials: AR
authors.lastname: Da Silva Melo
authors.affiliation: Programa de Pós Graduação em Biologia Celular e Molecular.
authors.forename: Haline
authors.initials: H
authors.lastname: Barroso
authors.affiliation: Departamento de Biologia Molecular, Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, João Pessoa, PB-Brazil.
authors.forename: Daniel
authors.initials: D
authors.lastname: Uchôa De Araújo
authors.affiliation: Departamento de Morfologia, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, PB-Brazil.
authors.forename: Francisco
authors.initials: F
authors.lastname: Ruidomar Pereira
authors.affiliation: Programa de Pós Graduação em Biologia Celular e Molecular,, Departamento de Biologia Molecular, Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, João Pessoa, PB-Brazil.
authors.forename: Naila Francis Paulo
authors.initials: NF
authors.lastname: De Oliveira
mesh_terms: D001707:Biopsy, Needle; D016022:Case-Control Studies; D019175:DNA Methylation / Q000235:genetics / Q000528:radiation effects*; D044127:Epigenesis, Genetic / Q000528:radiation effects; D005260:Female; D006801:Humans; D053547:Keratin-14 / Q000235:genetics / Q000528:radiation effects*; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000528:radiation effects*; D035683:MicroRNAs / Q000235:genetics / Q000528:radiation effects*; D016133:Polymerase Chain Reaction; D012016:Reference Values; D012494:Sampling Studies; D013472:Sunlight / Q000009:adverse effects*
chemical_list: C507540:KRT14 protein, human; D053547:Keratin-14; C545567:MIRN137 microRNA, human; D035683:MicroRNAs; D020780:Matrix Metalloproteinase 9
keywords: DNA methylation; MMP; epigenetic; keratin; microRNA; skin; sun