Enhanced contact allergen and UVB induced keratinocyte apoptosis in the absence of CD95/Fas/Apo-1

Ingo Haase (1) , Alina Hedrych- Ozimina (1) , Zhenyue Hao (1) , Ruth Pofahl (1) , Doreen Ussath (1) , Renate Knaup (1) , Kristina Behrendt (1) , Thomas Krieg (1)

1 Dept. of Dermatology

FAS/ CD95/ Apo- 1 is an ubiquitously expressed cell surface receptor involved in the initiation of programmed cell death. Its function in epidermal keratinocytes has been incompletely defined. Available evidence from in vitro studies points to important roles of Fas in the pathogenesis of contact dermatitis and in keratinocyte apoptosis induced by ultraviolet light. To define functions of Fas in the epidermis in vivo, we have generated mice with epidermis specific deletion of the fas gene and have tested its requirement for DNFB induced contact dermatitis and for UVB induced keratinocyte apoptosis. We report here our unexpected finding that keratinocyte apoptosis induced by both a contact allergen and UVB irradiation was significantly enhanced in Fas negative epidermis. Expression of Fas by epidermal keratinocytes was neither necessary for the normal development of contact hypersensitivity of the skin, nor required for keratinocyte apoptosis following UVB irradiation. Our results thus demonstrate that, in the epidermis in vivo, Fas exerts anti apoptotic functions that outweigh its pro apoptotic role in contact hypersensitivity responses of the skin and in the tissue response of the epidermis to UVB irradiation.

Mots clés: CD95; Fas; epidermis; apoptosis; sunburn cell

Ingo Haase, Alina Hedrych- Ozimina, Zhenyue Hao, Ruth Pofahl, Doreen Ussath, et al.. Enhanced contact allergen and UVB induced keratinocyte apoptosis in the absence of CD95/Fas/Apo-1. Cell Death and Differentiation, 2010, ⟨10.1038/cdd.2010.83⟩. ⟨hal-00563511⟩