Peroxynitrite production, DNA breakage, and poly(ADP-ribose) polymerase activation in a mouse model of oxazolone-induced contact hypersensitivity

J Invest Dermatol. 2001 Jul;117(1):74-80. doi: 10.1046/j.0022-202x.2001.01388.x.


Peroxynitrite-induced poly(ADP-ribose) polymerase activation has been implicated in the pathogenesis of various inflammatory conditions. Here we have investigated whether peroxynitrite and poly(ADP-ribose) polymerase may play a role in the pathophysiology of the elicitation phase of contact hypersensitivity. We have detected nitrotyrosine, DNA breakage, and poly(ADP-ribose) polymerase activation in the epidermis of mice in an oxazolone-induced contact hypersensitivity model. As tyrosine nitration is mostly mediated by peroxynitrite, a nitric-oxide-derived cytotoxic oxidant capable of causing DNA breakage, we have applied peroxynitrite directly on mouse skin and showed poly(ADP-ribose) polymerase activation in keratinocytes and in some scattered dermal cells. We have also investigated the cellular effects of peroxynitrite in HaCaT cells, a human keratinocyte cell line. We found that peroxynitrite inhibited cell proliferation and at higher concentrations also caused cytotoxicity. Peroxynitrite activates poly(ADP-ribose) polymerase in HaCaT cells and poly(ADP-ribose) polymerase activation contributes to peroxynitrite-induced cytotoxicity, as indicated by the cytoprotective effect of the poly(ADP-ribose) polymerase inhibitor 3-aminobenzamide. The cytoprotective effect of 3-aminobenzamide cannot be attributed to inhibition of apoptosis, as apoptotic parameters (caspase activation and DNA fragmentation) were not reduced in the presence of 3-aminobenzamide in peroxynitrite-treated cells. Moreover, poly(ADP-ribose) polymerase inhibition by 3-aminobenzamide dose-dependently reduced interferon-induced intercellular adhesion molecule 1 expression as well as interleukin-1beta-induced interleukin-8 expression. Our results indicate that peroxynitrite and poly(ADP-ribose) polymerase regulate keratinocyte function and death in contact hypersensitivity.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adjuvants, Immunologic
  • Animals
  • Apoptosis / drug effects
  • Apoptosis / physiology
  • Caspases / metabolism
  • Cell Division / drug effects
  • Cell Division / physiology
  • Cell Line
  • DNA Damage / physiology*
  • DNA Fragmentation / physiology
  • Dermatitis, Contact / genetics
  • Dermatitis, Contact / immunology
  • Dermatitis, Contact / metabolism*
  • Female
  • In Situ Nick-End Labeling
  • Intercellular Adhesion Molecule-1 / biosynthesis
  • Interleukin-8 / immunology
  • Keratinocytes / immunology
  • Keratinocytes / metabolism
  • Keratinocytes / pathology
  • Mice
  • Mice, Inbred Strains
  • Necrosis
  • Nitrates / metabolism*
  • Oxazolone
  • Poly(ADP-ribose) Polymerases / metabolism*
  • Skin / immunology
  • Skin / metabolism
  • Skin / pathology
  • Tyrosine / metabolism


  • Adjuvants, Immunologic
  • Interleukin-8
  • Nitrates
  • Intercellular Adhesion Molecule-1
  • Oxazolone
  • peroxynitric acid
  • Tyrosine
  • Poly(ADP-ribose) Polymerases
  • Caspases