Methylation of LOXL1 Promoter by DNMT3A in Aged Human Skin Fibroblasts

Rejuvenation Res. 2017 Apr;20(2):103-110. doi: 10.1089/rej.2016.1832. Epub 2016 Aug 11.

Abstract

Lysyl oxidase-like 1 (LOXL1) is an amino-oxidase involved in maturation of elastic fibers. Its downregulation has been associated with elastic fibers repair loss in aging aorta, lung, ligament, and skin. Several evidences of LOXL1 epigenetic silencing by promoter methylation were reported in cancer and cutis laxa syndrome. We hypothesized that this mechanism could be implicated in skin aging process, as far as elastic fibers are also concerned. Anti-DNMT3A chromatin immunoprecipitation was conducted with nuclear extracts from skin fibroblasts isolated from young and elderly individuals, and showed a higher level of DNMT3A protein binding to the LOXL1 promoter in older cells concomitantly to the decrease of LOXL1 mRNA expression and the increase of LOXL1 promoter methylation. Using luciferase reporter assay driven by LOXL1 promoter in HEK293 cells, we demonstrated that LOXL1 transcriptional activity was dramatically reduced when a recombinant DNMT3A was concomitantly overexpressed. LOXL1 promoter transcriptional activity was restored in the presence of a broad-spectrum inhibitor of DNMT activity, 5-aza-2'-deoxycytidine. Finally, to assess whether the interplay between DNMT3A and LOXL1 promoter could be targeted to increase LOXL1 mRNA expression level, an Origanum majorana extract was selected among 43 plant extracts as a new inhibitor of human DNMT3A activity to restore LOXL1 secretion without cytotoxicity in aged skin fibroblasts.

Keywords: DNA-methyltransferase; fibroblasts; lysyl oxidase-like 1; skin aging.

MeSH terms

  • Aging / genetics*
  • Amino Acid Oxidoreductases / genetics*
  • Amino Acid Oxidoreductases / metabolism
  • Cellular Senescence / drug effects
  • Cellular Senescence / genetics*
  • Child
  • Child, Preschool
  • DNA (Cytosine-5-)-Methyltransferases / genetics
  • DNA (Cytosine-5-)-Methyltransferases / metabolism*
  • DNA Methylation / drug effects
  • DNA Methylation / genetics*
  • Female
  • Fibroblasts / enzymology*
  • HEK293 Cells
  • Humans
  • Infant
  • Origanum / chemistry
  • Plant Extracts / pharmacology
  • Promoter Regions, Genetic*
  • Protein Binding / drug effects
  • Protein Binding / genetics
  • Skin / cytology*

Substances

  • Plant Extracts
  • Amino Acid Oxidoreductases
  • LOXL1 protein, human
  • DNA (Cytosine-5-)-Methyltransferases
  • DNA methyltransferase 3A