Differential response of basal keratinocytes in a human skin equivalent to ultraviolet irradiation.
The human skin equivalent (HSE) provides a convenient model system for studying the cellular responses of basal keratinocytes to UV irradiation. HSEs, constructed by overlaying a collagen-fibroblast matrix with epidermal cells, were raised to an air-liquid interface to promote epidermal differentiation. HSEs were exposed to ultraviolet radiation from a 500-W Hot Quartz Hanovia therapeutic sunlamp, at a total dose of 100 J/m2. The HSEs were then frozen every 4 h over a 48-h period and cryosectioned. For each time period, the expression of beta1 integrin and cyclin E, p53, or Bcl-2 were quantified using dual immunolocalization. Basal cells expressing beta1 integrin were divided into two subpopulations, denoted beta1high or beta1low. The proportion of beta1high keratinocytes expressing Bcl-2 and cyclin E increased significantly 4 and 8 h, respectively, after exposure to UV; during the subsequent 16 h, this basal cell subpopulation expressed p53. By contrast, significant numbers of beta1low basal keratinocytes expressed p53, but not Bcl-2. These results suggest that beta1high and beta1low populations of basal epidermal cells in HSEs respond differently to UV irradiation.
The Procter & Gamble Company, Winton Hill Technical Center, Cincinnati, Ohio 45224, USA.
S W
SW
Hendrix
J V
JV
Rogers
B E
BE
Hull
D000293:Adolescent; D000328:Adult; D000368:Aged; D019927:Cyclin E / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019012:Integrin beta1 / Q000378:metabolism; D015603:Keratinocytes / Q000166:cytology / Q000528:radiation effects*; D008297:Male; D008875:Middle Aged; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012867:Skin / Q000737:chemistry / Q000166:cytology / Q000528:radiation effects*; D017768:Skin, Artificial; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014466:Ultraviolet Rays
D019927:Cyclin E; D019012:Integrin beta1; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53