Reduced MiR-675 in exosome in H19 RNA-related melanogenesis via MITF as a direct target

J Invest Dermatol. 2014 Apr;134(4):1075-1082. doi: 10.1038/jid.2013.478. Epub 2013 Nov 11.

Abstract

H19 non-coding RNA downregulation stimulates melanogenesis in melasma patients. However, its mechanism is unclear. In this study, the potential role of a H19 microRNA, miR-675, in melanogenesis was examined. Real-time PCR using cultured normal human skin keratinocytes, melanocytes, and fibroblasts with or without H19 knockdown showed accompanying changes between expression levels of H19 and those of miR-675 in keratinocytes. MiR-675 was also detected in concentrated culture supernatants and showed expression levels parallel with those of cell lysates. In addition to RNase resistance, FACS analysis showed anti-CD63-positive exosomes in culture supernatants, suggesting miR-675 could be released extracellularly and delivered to neighboring cells without degradation. In western blot analysis, the miR-675 mimic reduced the expression of microphthalmia-associated transcription factor (MITF) and phosphorylation of cAMP-responsive element-binding protein, extracellular signal-regulated kinase and apoptosis signal-regulating kinase, whereas these expressions were increased by the miR-675 inhibitor. Although H19 was not a miR-675 target, luciferase reporter assay showed a direct binding of miR-675 to 3'-untranslated region of MITF. In addition, localized in vivo miR-675 overexpression in mouse using a cationic polymer transfection reagent showed reduced mRNA expression levels of MITF, tyrosinase, tyrosine-related protein-1 (Trp-1), and Trp-2. Collectively, the results suggest that miR-675 derived from keratinocytes could be involved in H19-stimulated melanogenesis using MITF as a target of miR-675.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3' Untranslated Regions
  • Animals
  • Apoptosis
  • Cell Separation
  • Epidermis / metabolism
  • Exosomes / metabolism
  • Female
  • Fibroblasts / cytology
  • Fibroblasts / metabolism
  • Flow Cytometry
  • Gene Expression Regulation
  • Humans
  • Keratinocytes / cytology
  • Melanocytes / cytology*
  • Mice
  • Mice, Inbred C57BL
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism
  • Microphthalmia-Associated Transcription Factor / metabolism*
  • Oligonucleotide Array Sequence Analysis
  • RNA, Long Noncoding / genetics*
  • Tetraspanin 30 / metabolism

Substances

  • 3' Untranslated Regions
  • H19 long non-coding RNA
  • MIRN675 microRNA, human
  • MIRN675 microRNA, mouse
  • MITF protein, human
  • MicroRNAs
  • Microphthalmia-Associated Transcription Factor
  • Mitf protein, mouse
  • RNA, Long Noncoding
  • Tetraspanin 30