[TAK1 promotes epithelial-mesenchymal transition of lens epithelial cells].
OBJECTIVE
Transforming growth factor-β-activated kinase-1 (TAK1) is thought to play a key role in the initiation of Smad-independent TGF-β signaling. This study investigated the role of TAK1 in the epithelial-mesenchymal transition (EMT) lens epithelial cells.


METHODS
TAK1 was overexpressed in the HLE B-3 cell line by transfecting TAK1-pcDNA3 and TAK1-binding protein 1 (TAB1)-pcDNA3 plasmids. The expression levels of TAK1, phospho-TAK1, E-cadherin, and fibronectin were detected by Western blot analysis and immunocytofluorescence to analyze the effects of overexpression. The levels of α-SMA and type I collagen were analyzed by real-time PCR. Quantitative data were analyzed by Student's t test or one-way analysis of variance (ANOVA) (multiple comparisons using LSD test).


RESULTS
Western blot analysis showed in the TAK1-pcDNA3 plasmids group, expression of TAK1 proteins (1.00±0.03) with a maximum upregulation of approximately 80% at 24 h than it was in the control group (0.19±0.09)(t=8.02, P< 0.01); Western blot analysis showed in the TAB1-pcDNA3 plasmids group, expression of TAB1 proteins (1.00±0.02) with a maximum upregulation of approximately 78% at 24 h than it was in the control group (0.22±0.08)(t=7.63, P<0.01). The levels of E-cadherin/Beta-actin had significant differences among control, overexpression of TAK1 together with TAB1, overexpression of TAK1, and overexpression of TAB1 (1.00±0.02, 0.12±0.03, 0.98±0.09, 0.92±0.08;F=31.03, P<0.01). The levels of fibronectin/Beta-actin had significant differences among control, overexpression of TAK1 together with TAB1, overexpression of TAK1, and overexpression of TAB1 (0.11±0.03, 1.00±0.05, 0.16±0.04, 0.21±0.05;F=35.12, P<0.01). Overexpression of TAK1 with TAB1 resulted in upregulated expression of fibronectin, and downregulated expression of E-cadherin. The expression of E-cadherin was increased and the expression of fibronectin was decreased by TAK1 siRNA and TAK1 chemical inhibitors in the presence of TGF-β2.


CONCLUSIONS
These data reveal that TAK1 can induce the EMT of HLE cells, and the inhibition of TAK1 phosphorylation may be a potential novel therapeutic target for the prevention and treatment of posterior capsule opacification. (Chin J Ophthalmol, 2016, 52: 278-284).
Clinical College of Ophthalmology, Tianjin Medical University, Tianjin Eye Hospital, Tianjin 300020, China.
N
N
Dong
X
X
Tang
X Y
XY
Yuan
H
H
Song
J
J
Li
D000199:Actins / Q000235:genetics / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D058442:Capsule Opacification / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D024042:Collagen Type I; D004847:Epithelial Cells / Q000378:metabolism; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics*; D005353:Fibronectins / Q000235:genetics / Q000378:metabolism; D020930:MAP Kinase Kinase Kinases / Q000235:genetics*; D010766:Phosphorylation; D060888:Real-Time Polymerase Chain Reaction; D014162:Transfection; D053781:Transforming Growth Factor beta2; D000099151:MAP Kinase Kinase Kinase 7
D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D015820:Cadherins; D024042:Collagen Type I; D005353:Fibronectins; D020930:MAP Kinase Kinase Kinases; D053781:Transforming Growth Factor beta2; D000099151:MAP Kinase Kinase Kinase 7; C541116:ACTA2 protein, human; C513384:CDH1 protein, human; C067625:FN1 protein, human; C486300:TAB1 protein, human