Differential responses of normal human melanocytes to intra- and extracellular dsRNA

DNA Cell Biol. 2015 Jun;34(6):391-9. doi: 10.1089/dna.2014.2711. Epub 2015 Mar 24.

Abstract

Viral factor has been implicated in the etiopathogenesis of vitiligo. To elucidate the effects of viral double-stranded RNA (dsRNA) on melanocytes and to explore the underlying mechanisms, primary cultured normal human melanocytes were treated with synthetic viral dsRNA analog poly(I:C). The results demonstrated that poly(I:C)-triggered apoptosis when transfected into melanocytes, while extracellular poly(I:C) did not have that effect. Intracellular poly(I:C)-induced melanocyte death was decreased by RIG-I or MDA5 siRNA, but not by TLR3 siRNA. Both intracellular and extracellular poly(I:C) induced the expression of IFNB, TNF, IL6, and IL8. However, extracellular poly(I:C) demonstrated a much weaker induction capacity of cytokine genes than intracellular poly(I:C). Further analysis revealed that phosphorylation of TBK1, IRF3, IRF7, and TAK1 was differentially induced by intra- or extracellular poly(I:C). NFκB inhibitor Bay 11-7082 decreased the induction of all the cytokines by poly(I:C), suggesting the ubiquitous role of NFκB in the process. Poly(I:C) treatment also induced the phosphorylation of p38 and JNK in melanocytes. Both JNK and p38 inhibitors showed suppression on the cytokine induction by intra- or extracellular poly(I:C). However, only the JNK inhibitor decreased the intracellular poly(I:C)-induced melanocyte death. Taken together, this study provides the possible mechanism of viral factor in the pathogenesis of vitiligo.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis
  • Cells, Cultured
  • Cytokines / genetics
  • Cytokines / metabolism
  • DEAD Box Protein 58
  • DEAD-box RNA Helicases / metabolism
  • Humans
  • Interferon-Induced Helicase, IFIH1
  • Melanocytes / physiology*
  • NF-kappa B / metabolism
  • Phosphorylation
  • Poly I-C / pharmacology*
  • Protein Processing, Post-Translational
  • RNA, Double-Stranded / pharmacology*
  • RNA, Viral / pharmacology
  • Receptors, Immunologic
  • Transcriptional Activation / drug effects
  • Vitiligo / virology
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • Cytokines
  • NF-kappa B
  • RNA, Double-Stranded
  • RNA, Viral
  • Receptors, Immunologic
  • p38 Mitogen-Activated Protein Kinases
  • RIGI protein, human
  • IFIH1 protein, human
  • DEAD Box Protein 58
  • DEAD-box RNA Helicases
  • Interferon-Induced Helicase, IFIH1
  • Poly I-C