MEK/ERK pathway mediates UVB-induced AQP1 downregulation and water permeability impairment in human retinal pigment epithelial cells.
Aquaporins (AQPs) are a family of 13 small ( approximately 30 kDa/monomer), hydrophobic, integral membrane proteins. AQPs are expressed in various epithelial and endothelial cells involved in fluid transport. Here, we demonstrated for the first time that AQP1 is expressed in cultured human retinal pigment epithelial (RPE) cells (ARPE-19 cell line). Ultraviolet radiation (UVB) and H2O2, two major factors causing RPE cell damage, induced AQP1 downregulation which was mediated by MEK/ERK activation. UV and H2O2 as well as AQP1-specific siRNA knockdown impaired water permeability of ARPE-19 cells. Notably, pretreatment with all-trans retinoic acid attenuated UV- and H2O2-induced AQP1 downregulation and water permeability impairment. Considering that water permeability is involved in multiple functions of RPE cells such as cellular junction formation, fluid or protein exchange and barrier formation, our data elucidated a novel mechanism through which UV radiation and oxidative stress induce eye cell damage. Our results further support the notion that all-trans retinoic acid might be useful for protection against UV or oxidative stress-induced eye cell damage.
Eye Hospital, Nanjing Medical University, Nanjing 210029, People's Republic of China. jqin710@vip.sina.com
Qin
Q
Jiang
Cong
C
Cao
Shan
S
Lu
Rebecca
R
Kivlin
Brittany
B
Wallin
Wenming
W
Chu
Zhigang
Z
Bi
Xinru
X
Wang
Yinsheng
Y
Wan
D051398:Aquaporin 1 / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000528:radiation effects*; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism*; D010857:Pigment Epithelium of Eye / Q000166:cytology*; D034741:RNA, Small Interfering / Q000235:genetics / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology; D014466:Ultraviolet Rays; D014867:Water / Q000378:metabolism*
D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D014867:Water; D051398:Aquaporin 1; D014212:Tretinoin; D006861:Hydrogen Peroxide; D020929:Mitogen-Activated Protein Kinase Kinases