Ultraviolet B-induced apoptosis of human skin fibroblasts involves activation of caspase-8 and -3 with increased expression of vimentin.
BACKGROUND
After irradiation with a high dose of ultraviolet B (UVB), cells undergo apoptosis. Caspase-8 and -3 are key mediators of apoptosis in many cells. Vimentin, an important cytoskeleton component, can be cleaved by caspase-3, -6, -7 and -8. Cell apoptosis is promoted via caspase-triggered proteolysis of vimentin. In this study, we explored the roles of caspase-8 and -3 and the changes in vimentin expression in UVB-induced apoptosis of human dermal fibroblasts.


METHODS
Skin fibroblasts were irradiated with 150 mJ/cm(2) UVB and cell death was monitored by the 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-diphenytetrazoliumromide assay and Hoechst staining. Caspase-8 and -3 activities were detected by the caspase activity assay. Vimentin expression was assessed by immunofluorescence and Western blot.


RESULTS
Caspase-8 and -3 were activated by 150 mJ/cm(2) UVB irradiation. Caspase-8 and -3 activities changed in a time-dependent way after UVB irradiation to induce apoptosis of fibroblasts, and caspase-8 and -3 interacted with each other in this process. However, their substrate, vimentin, showed an enhanced expression over time after UVB irradiation.


CONCLUSIONS
UVB-triggered apoptosis of fibroblasts was dependent on the activation of caspase-8 and -3 with an increased expression of vimentin.
Xu
Haoxiang
H
Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Yan
Yan
Y
Li
Li
L
Peng
Shiguang
S
Qu
Tao
T
Wang
Baoxi
B
D017209:Apoptosis / Q000528:radiation effects*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism*; D053181:Caspase 8 / Q000378:metabolism*; D004789:Enzyme Activation; D005347:Fibroblasts / Q000201:enzymology; D005455:Fluorescent Antibody Technique; D006801:Humans; D012867:Skin / Q000166:cytology / Q000201:enzymology*; D014466:Ultraviolet Rays; D014746:Vimentin / Q000378:metabolism*
D014746:Vimentin; D053148:Caspase 3; D053181:Caspase 8