Role of LOX-1 and ROS in oxidized low-density lipoprotein induced epithelial-mesenchymal transition of NRK52E.
BACKGROUND
To investigate the effect of oxidized low density lipoprotein receptor-1 (LOX-1) on tubular epithelial-mesenchymal transition (TEMT) induced by oxidized low-density lipoprotein (ox-LDL) and its mechanism.


METHODS
NRK-52E cells were incubated with ox-LDL (0, 25, 50, and 100 μg/ml) for 24 hours or pre-treated with the chemical inhibitor of the LOX-1 receptor polyinosinic acid (poly I) and carrageenan or the antioxidant N-acetyl-L-cysteine (NAC), the cells were then exposed to 50 μg/ml of ox-LDL.The expression of LOX-I, E-cadherin, α-smooth muscle actin (α-SMA) and reactive oxygen species (ROS) were analyzed by real-time PCR, western blotting analysis, immunofluorescence and confocal laser scanning microscopy.


RESULTS
Ox-LDL increased the expression of LOX-1 mRNA and protein in a dose-dependent manner from 0 to 100 μg/ml (P < 0.05). Following the increase in the LOX-1 protein level, the lipid intake, ROS generation and α-SMA expression increased; however, the E-cadherin level decreased. The pre-treatment with poly I or carrageenan or NAC significantly inhibited the LOX-1 expression, α-SMA expression, the lipid intake and ROS generation and reversed decrease of E-cadherin expression induced by ox-LDL. Meanwhile, the ROS generation were associated with a increase in the LOX-1 expression. The α-SMA expression was positively correlated with the ROS generation and LOX-1 expression, and the E-cadherin expression was negatively correlated with the ROS generation and LOX-1 expression.


CONCLUSIONS
LOX-1 and ROS may play a important role in epithelial-mesenchymal transition of NRK52E induced by OX-LDL.
Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, China.
Rui
R
Wang
Guohua
G
Ding
Wei
W
Liang
Cheng
C
Chen
Hongxia
H
Yang
D000818:Animals; D002460:Cell Line; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects*; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D018613:Microscopy, Confocal; D016133:Polymerase Chain Reaction; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D051127:Scavenger Receptors, Class E / Q000235:genetics / Q000378:metabolism*
D008077:Lipoproteins, LDL; C495136:OLR1 protein, rat; D017382:Reactive Oxygen Species; D051127:Scavenger Receptors, Class E; C099252:oxidized low density lipoprotein