Low-dose UVB irradiation stimulates matrix metalloproteinase-1 expression via a BLT2-linked pathway in HaCaT cells.
Skin exposure to low-dose ultraviolet B (UVB) light up-regulates the expression of matrix metalloproteinase-1 (MMP-1), thus contributing to premature skin aging (photo-aging). Although cyclooxygenase-2 (COX- 2) and its product, prostaglandin E(2) (PGE((2))), have been associated with UVB-induced signaling to MMP expression, very little are known about the roles of lipoxygenases and their products, especially leukotriene B((4)) (LTB((4))) and 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE), in MMP-1 expression in skin keratinocytes. In the present study, we demonstrate that BLT2, a cell surface receptor for LTB((4)) and 12(S)-HETE, plays a critical role in UVB-mediated MMP-1 upregulation in human HaCaT keratinocytes. Moreover, our results demonstrated that BLT2-mediated MMP-1 upregulation occurs through a signaling pathway dependent on reactive oxygen species (ROS) production and the subsequent stimulation of ERK. Blockage of BLT2 via siRNA knockdown or with the BLT2-antagonist LY255283 completely abolished the up-regulated expression of MMP-1 induced by low-dose UVB irradiation. Finally, when HaCaT cells were transiently transfected with a BLT2 expression plasmid, MMP-1 expression was significantly enhanced, along with ERK phosphorylation, suggesting that BLT2 overexpression alone is sufficient for MMP-1 up-regulation. Together, our results suggest that the BLT2-ROS- ERK-linked cascade is a novel signaling mechanism for MMP-1 upregulation in low-dose UVB- irradiated keratinocytes and thus potentially contributes to photo-aging.
College of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
Cheolmin
C
Kim
Ho-Cheol
HC
Ryu
Jae-Hong
JH
Kim
D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000096:biosynthesis; D002460:Cell Line; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000528:radiation effects*; D007975:Leukotriene B4 / Q000096:biosynthesis; D020781:Matrix Metalloproteinase 1 / Q000096:biosynthesis*; D010766:Phosphorylation; D017382:Reactive Oxygen Species / Q000378:metabolism; D018102:Receptors, Leukotriene B4 / Q000502:physiology*; D015398:Signal Transduction; D014466:Ultraviolet Rays / Q000009:adverse effects*
C485878:LTB4R2 protein, human; D017382:Reactive Oxygen Species; D018102:Receptors, Leukotriene B4; D007975:Leukotriene B4; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D048049:Extracellular Signal-Regulated MAP Kinases; C522360:MMP1 protein, human; D020781:Matrix Metalloproteinase 1