scholarly journals AKR1B1-Induced Epithelial–Mesenchymal Transition Mediated by RAGE-Oxidative Stress in Diabetic Cataract Lens

Antioxidants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 273 ◽  
Author(s):  
Tsung-Tien Wu ◽  
Ying-Ying Chen ◽  
Hui-Yu Chang ◽  
Ya-Hsin Kung ◽  
Ching-Jiunn Tseng ◽  
...  

Purpose: Cataracts are a major cause of visual acuity deterioration in diabetes mellitus (DM) in developed and developing countries. Studies have demonstrated that overproduction of AKR1B1 and receptor for advanced glycation end products (RAGE) plays a major role in the pathogenesis of diabetic cataracts, but it is unclear whether the prevalence of diabetic cataracts is related to epithelial–mesenchymal transition (EMT) in lens epithelial cells. This study aimed to analyze the role of EMT in cataract formation of DM patients. Methods: Immunofluorescence and immunohistochemistry assays were used to estimate AKR1B1, RAGE, AMPK, and EMT levels in epithelial human lens of DM or non-DM cataracts. Results: Immunohistochemical staining demonstrated that pathologic phases and N-cadherin expression levels were significantly higher in epithelial human lens of DM (+) compared to DM (−) cataracts. Immunofluorescent staining showed that AKR1B1 and RAGE were significantly higher in epithelial human lens of DM (+) compared to DM (−) cataracts. Interestingly, acetyl superoxide dismutase 2 (AcSOD2) levels were significantly higher in DM patients’ lens epithelial cells (LECs), whereas AMPKT172 phosphorylation was significantly increased in non-DM patients. This indicates that AMPKT172 might be related to superoxide reduction and diabetic cataract formation. Conclusions: Our results suggest that AKR1B1 overexpression can decrease AMPK activation, thereby increasing AcSOD2 and RAGE-induced EMT in epithelial human lens of DM cataracts. These novel findings suggest that AKR inhibitors may be candidates for the pharmacological prevention of cataracts in patients with DM.

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1086
Author(s):  
Tsung-Tien Wu ◽  
Ying-Ying Chen ◽  
Chiu-Yi Ho ◽  
Tung-Chen Yeh ◽  
Gwo-Ching Sun ◽  
...  

Studies demonstrated that the receptor of advanced glycation end products (RAGE) induced epithelial-mesenchymal transition (EMT) formation in the lens epithelial cells (LECs) of diabetic cataracts. This work investigated how 3H-1,2-dithiole-3-thione (D3T) reduces EMT formation in LECs of the fructose-induced diabetes mellitus (DM). LECs were isolated during cataract surgery from patients without DM or with DM. In a rat model, fructose (10% fructose, eight weeks) with or without D3T (10 mg/kg/day) treatment induced DM, as verified by blood pressure and serum parameter measurements. We observed that the formation of advanced glycation end products (AGEs) was significantly higher in epithelial human lens of DM (+) compared to DM (−) cataracts. Aldose reductase (AKR1B1), AcSOD2, and 3-NT were significantly enhanced in the rat lens epithelial sections of fructose-induced DM, however, the phosphorylation level of AMPKT172 showed a reversed result. Interestingly, administration of D3T reverses the fructose-induced effects in LECs. These results indicated that AMPKT172 may be required for reduced superoxide generation and the pathogenesis of diabetic cataract. Administration of D3T reverses the fructose-induced EMT formation the LECs of fructose-induced DM. These novel findings suggest that the D3T may be a candidate for the pharmacological prevention of cataracts in patients with DM.


2012 ◽  
Vol 449 (1) ◽  
pp. 241-251 ◽  
Author(s):  
Seok-Jo Kim ◽  
Tae-Wook Chung ◽  
Hee-Jung Choi ◽  
Choong-Hwan Kwak ◽  
Kwon-Ho Song ◽  
...  

TGF-β (transforming growth factor-β)-induced EMT (epithelial–mesenchymal transition) induces the proliferation and migration of the HLE (human lens epithelial) cells. Ganglioside GM3, simple sialic-acid-containing glycosphingolipids on mammalian cell membranes, regulates various pathological phenomena such as insulin resistance and tumour progression. However, the relationship between ganglioside GM3 and TGF-β-induced EMT in the HLE B-3 cells is poorly understood. In the present study we demonstrated that ganglioside GM3 was involved in TGF-β1-induced EMT in HLE B-3 cells. Our results indicated that the expression of ganglioside GM3 and GM3 synthase mRNA were significantly increased in TGF-β1-induced HLE B-3 cells. Reporter gene analysis also demonstrated that transcriptional activation of the GM3 synthase gene was regulated by Sp1 (specificity protein 1) in HLE B-3 cells upon TGF-β1 stimulation. Interestingly, the inhibition of ganglioside GM3 expression by d-PDMP [d-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol] and GM3 synthase shRNA (short hairpin RNA) resulted significantly in the suppression of cell migration and EMT-related signalling in HLE B-3 cells stimulated by TGF-β. Furthermore, exogenous treatment of ganglioside GM3 rescued the expression of EMT molecules and cell migration suppressed by the depletion of ganglioside GM3 in TGF-β1-induced HLE B-3 cells. We also found that ganglioside GM3 interacted with TGFβRs (TGF-β receptors) in TGF-β1-induced HLE B-3 cells. Taken together, these results suggest that ganglioside GM3 induced by TGF-β1 regulates EMT by potential interaction with TGFβRs.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Ning Dong ◽  
Bing Xu ◽  
Jingmei Xu

The previous study has demonstrated that epidermal growth factor (EGF) and EGF receptor (EGFR) signaling plays a critical role in the development of posterior capsule opacification (PCO) through regulating lens epithelial cells (LECs) proliferation. Recent studies have suggested that the residual LECs undergo proliferation and migration, and epithelial-mesenchymal transition (EMT) is the important cause of PCO formation after cataract surgery. EMT of LECs is considered to be playing a central role in the pathogenesis of PCO. In the present study, we investigated whether and how EGF may regulate EMT of LECs. First, we demonstrated that EGF and EGFR signaling induces Myc overexpression in primary human lens epithelial cells (HLECs). In turn, Myc overexpression could inhibit miR-26b by recruitment of HDAC3. Consequently, the downregulated expression of miR-26b increased the expression of EZH2 in primary HLECs. Mechanistically, miR-26b directly controls EZH2 expression by targeting its 3′-UTR in HLECs by luciferase reporter assays. Finally, we demonstrated that EGF induces the expression of EMT markers in primary HLECs via a miR-26b-dependent mechanism. In summary, EGF activated Myc and Myc overexpression inhibited miR-26b by recruitment of HDAC3, which in turn induced the expression of EZH2 and promoted the progression of EMT in HLECs.


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