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

Éva Szabó, László Virág, Edina Bakondi, László Gyüre, György Haskó, Péter Bai, János Hunyadi, Pál Gergely, Csaba Szabó

Research output: Contribution to journalArticlepeer-review

62 Scopus citations


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-1β-induced interleukin-8 expression. Our results indicate that peroxynitrite and poly(ADP-ribose) polymerase regulate keratinocyte function and death in contact hypersensitivity.

Original languageEnglish (US)
Pages (from-to)74-80
Number of pages7
JournalJournal of Investigative Dermatology
Issue number1
StatePublished - 2001
Externally publishedYes


  • Apoptosis
  • Inflammation
  • Interleukin-8
  • Keratinocyte
  • Necrosis

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Dermatology
  • Cell Biology


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