UVB radiation suppresses the TNF-alpha-induced expression of E-selectin and ICAM-1 on cultured human umbilical vein endothelial cells.
Endothelial cells, which are involved in the development of inflammatory and immune responses, can express various kinds of cell adhesion molecules (CAM) including E-selectin and intercellular adhesion molecules-I (ICAM-I). These cell adhesion molecules and their ligands on leukocytes play an essential role in the control of extravasation of inflammatory cells. Ultraviolet B (UVB) radiation can reach the upper dermis and modulate CAM expressions on vascular endothelial cells (EC). We examined the direct effect of UVB on E-selectin and ICAM-I expression on cultured human umbilical vein endothelial cells (HUVEC) and also examined its effect on these cells induced by tumour necrosis factor-alpha (TNF-alpha), which is a potent CAM-inducer and is released by UVB radiation on the skin. Various doses of UVB were exposed to human umbilical vein endothelial cells (HUVEC) and these expressions were examined by flow cytometric analysis using FACScan; 5, 10 and 25 mJ/cm2 UVB induced neither E-selectin nor ICAM-I expression. Irradiation of HUVEC with UVB 30 min after treatment with TNF-alpha inhibited these expressions. Although the inhibition of E-selectin was observed until 12 h in a dose-dependent manner, ICAM-I expression was almost completely inhibited, even at 5 mJ/cm2 UVB. UVB irradiation before TNF-alpha stimulation showed similar effects to those obtained post-irradiation. This study has demonstrated that UVB can directly down-regulate EC functions, and the results may have implications in action mechanisms of UVB therapy.
Department of Dermatology, Kansai Medical University, Osaka, Japan.
M
M
Yamawaki
S
S
Futamura
T
T
Horio
D002478:Cells, Cultured; D015536:Down-Regulation / Q000528:radiation effects; D019040:E-Selectin / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism*; D007700:Kinetics; D012867:Skin / Q000098:blood supply / Q000378:metabolism / Q000528:radiation effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014466:Ultraviolet Rays
D019040:E-Selectin; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1