Endothelin-1 mediated high glucose-induced epithelial-mesenchymal transition in renal tubular cells.
OBJECTIVE
The pathogenesis of interstitial fibrosis in diabetic nephropathy (DN) is an intractable problem without good therapy. Emerging evidence suggests that epithelial-mesenchymal transition (EMT) is an important mechanism for tubular epithelial cells undergoing profibrotic change in DN. Endothelin-1 (ET-1) is an important cytokine which can cause fibrogenesis and is reportedly involved in DN. However, the role of ET-1 in EMT in DN is unknown. The present study was designed to investigate the role of ET-1 in high glucose-induced EMT and the signaling pathway mediating the effect of ET-1 in renal tubular cells.


METHODS
Tubular epithelial cells (NRK52E) were treated with normal glucose (d-glucose 5.6mmol/L, NG), high glucose (30mmol/L, HG), high osmotic (d-glucose 5.6mmol/L+d-mannitol 24.4mmol/L), HG+ETA antagonist BQ123 (2μg/ml), ET-1, ET-1+ hypoxia inducible factor (HIF)-1α siRNA, CoCl2 (100μmol/L), CoCl2+HIF-1α siRNA or CoCl2+BQ123. The supernatant level of ET-1 was measured by ELISA and the expression of vimentin, E-cadherin and HIF-1α was detected by RT-PCR and western blot.


RESULTS
The ET-1 level increased markedly in the supernatant of NRK52E incubated with HG. In NRK52E induced with HG or ET-1, the expression of vimentin was upregulated, whereas the expression of E-cadherin was downregulated. BQ123 attenuated HG- and CoCl2-induced EMT while HIF-1α siRNA did not affect ET-1 induced EMT.


CONCLUSIONS
High glucose induced ET-1 production that mediated the EMT induced by high glucose in renal tubular epithelial cells, and HIF-1α acted as the upstream signal to regulate ET-1.
Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, PR China. Electronic address: tanglin0627@gmail.com.
Lin
L
Tang
Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, PR China.
Hui
H
Li
Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, PR China.
Rong
R
Gou
Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, PR China.
Genyang
G
Cheng
Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, PR China.
Yuanyuan
Y
Guo
Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, PR China.
Yudong
Y
Fang
Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, PR China.
Fengmei
F
Chen
D000818:Animals; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental; D003928:Diabetic Nephropathies / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D019332:Endothelin-1 / Q000096:biosynthesis / Q000235:genetics*; D004797:Enzyme-Linked Immunosorbent Assay; D058750:Epithelial-Mesenchymal Transition; D005786:Gene Expression Regulation; D005947:Glucose / Q000633:toxicity; D015151:Immunoblotting; D007684:Kidney Tubules / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D012313:RNA / Q000235:genetics*; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction
D019332:Endothelin-1; D012313:RNA; D005947:Glucose
Diabetic nephropathy; Fibrosis; Hypoxia inducible factor