Bang Bo, Gniadecki Robert, Larsen Jørgen K, Baadsgaard Ole, Skov Lone
Department of Dermatology, Gentofte Hospital, Copenhagen, Denmark.
Exp Dermatol. 2003 Dec;12(6):791-8. doi: 10.1111/j.0906-6705.2003.00091.x.
In vitro studies with human cell lines have demonstrated that the death receptor Fas plays a role in ultraviolet (UV)-induced apoptosis. The purpose of the present study was to investigate the relation between Fas expression and apoptosis as well as clustering of Fas in human epidermis after a single dose of UVB irradiation. Normal healthy individuals were irradiated with three minimal erythema doses (MED) of UVB on forearm or buttock skin. Suction blisters from unirradiated and irradiated skin were raised, and Fas, FasL, and apoptosis of epidermal cells quantified by flow cytometry. Clustering of Fas was from skin biopsied. Soluble FasL in suction blister fluid was quantified by ELISA. Flow cytometric analysis demonstrated increased expression intensity of Fas after irradiation, with 1.6-,2.2- and 2.7-fold increased median expression at 24, 48 and 72 h after irradiation, respectively (n=4). Apoptosis was demonstrated by the TUNEL reaction, and the maximum of apoptotic cells was detected at 48 h after irradiation. Double-staining of Fas and TUNEL showed that apoptosis was restricted to the Fas-positive epidermal subpopulation, but there was no correlation between the intensities of Fas expression and TUNEL reaction. Median expression intensity of FasL-positive cells transiently decreased to 0.9- and 0.8-fold of the preirradiation respective level after 24 h and 48 h, respectively, and returned to the respective preirradiation level at 72 h after irradiation (n=4). Concentrations of soluble FasL in suction blister fluid from UVB-irradiated skin did not differ from those in unirradiated skin (n=5). Confocal laser scanning microscopy showed a rapid clustering of Fas within 30 min after irradiation. A simultaneous clustering of the adapter signalling protein FADD suggested that Fas clustering has a functional significance. Our results ar in accordance with previous findings from in vitro studies, and suggest that Fas is activated in vivo in human epidermis after UVB exposure.
对人类细胞系进行的体外研究表明，死亡受体Fas在紫外线（UV）诱导的细胞凋亡中发挥作用。本研究的目的是调查单次剂量UVB照射后人类表皮中Fas表达与细胞凋亡以及Fas聚集之间的关系。正常健康个体的前臂或臀部皮肤接受三次最小红斑量（MED）的UVB照射。从未照射和照射过的皮肤产生抽吸水疱，通过流式细胞术对表皮细胞的Fas、FasL和细胞凋亡进行定量。Fas的聚集来自皮肤活检。通过ELISA对抽吸水疱液中的可溶性FasL进行定量。流式细胞术分析显示照射后Fas表达强度增加，照射后24、48和72小时的中位表达分别增加了1.6倍、2.2倍和2.7倍（n = 4）。通过TUNEL反应证实了细胞凋亡，并且在照射后48小时检测到凋亡细胞的最大值。Fas和TUNEL的双重染色表明细胞凋亡仅限于Fas阳性的表皮亚群，但Fas表达强度与TUNEL反应之间没有相关性。FasL阳性细胞的中位表达强度在24小时和48小时后分别短暂降至照射前各自水平的0.9倍和0.8倍，并在照射后72小时恢复到各自的照射前水平（n = 4）。UVB照射皮肤的抽吸水疱液中可溶性FasL的浓度与未照射皮肤中的浓度没有差异（n = 5）。共聚焦激光扫描显微镜显示照射后30分钟内Fas迅速聚集。衔接子信号蛋白FADD的同时聚集表明Fas聚集具有功能意义。我们的结果与先前体外研究的结果一致，并表明UVB暴露后人类表皮中的Fas在体内被激活。
