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Protective effects of catalase overexpression on UVB-induced apoptosis in normal human keratinocytes

Hamid Reza Rezvani1, Frédéric Mazurier, Muriel Cario-André

  • 1INSERM E0217, University Victor Segalen Bordeaux 2, Bordeaux F-33000, France.

The Journal of Biological Chemistry
|April 29, 2006
PubMed

Insights

Overexpressing catalase protects skin cells from UVB damage by reducing late-stage reactive oxygen species (ROS) and preventing DNA damage. Low temperatures also reduce UV-induced apoptosis in keratinocytes.

Area of Science:

  • Dermatology
  • Molecular Biology
  • Cell Biology

Background:

  • UVB radiation induces apoptosis in keratinocytes through extrinsic and intrinsic pathways.
  • Reactive oxygen species (ROS) play a significant role in UV-induced DNA damage and apoptosis.

Purpose of the Study:

  • To investigate the protective effects of catalase and CuZn-superoxide dismutase (SOD) overexpression against UVB-induced apoptosis in human keratinocytes.
  • To elucidate the role of ROS and temperature in UVB-induced apoptosis.

Main Methods:

  • Overexpression of catalase and CuZn-SOD in normal human keratinocytes.
  • Exposure of keratinocytes to UVB irradiation at room temperature and 4°C.
  • Assessment of apoptosis, p53 levels, caspase activation, and ROS levels.

Main Results:

  • Irradiation at 4°C reduced UV-induced apoptosis by 40%, decreasing caspase-8 activation.
  • Catalase overexpression reduced apoptosis by 40%, decreasing caspase-9 activation and p53 levels.
  • Catalase overexpression inhibited the late-stage increase in ROS, while CuZn-SOD had no significant effect.

Conclusions:

  • Catalase overexpression confers a protective role against UVB irradiation by mitigating DNA damage mediated by late-stage ROS.
  • Low temperature reduces UVB-induced apoptosis, suggesting a role for ROS in temperature-dependent UV damage.

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