Beta-casomorphin-7 prevents epithelial-mesenchymal transdifferentiation of NRK-52E cells at high glucose level: Involvement of AngII-TGF-β1 pathway

Wei Zhang; Shangxin Song; Fei Liu; Yi Liu; Yuanshu Zhang

doi:10.1016/j.peptides.2015.04.002

Beta-casomorphin-7 prevents epithelial-mesenchymal transdifferentiation of NRK-52E cells at high glucose level: Involvement of AngII-TGF-β1 pathway

Peptides. 2015 Aug:70:37-44. doi: 10.1016/j.peptides.2015.04.002. Epub 2015 Apr 14.

Authors

Wei Zhang¹, Shangxin Song², Fei Liu³, Yi Liu³, Yuanshu Zhang⁴

Affiliations

¹ Key Lab of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agriculture University, Nanjing, 210095, People's Republic of China; Key Lab of Human Function Genomics Jiangsu Province, Nanjing Medical University, Nanjing, 210029, People's Republic of China.
² Key Laboratory of Meat Processing and Quality Control, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, People's Republic of China; Key Laboratory of Agricultural and Animal Products Processing and Quality Control, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.
³ Key Lab of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agriculture University, Nanjing, 210095, People's Republic of China.
⁴ Key Lab of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agriculture University, Nanjing, 210095, People's Republic of China. Electronic address: zhangyuanshu@njau.edu.cn.

PMID: 25882007
DOI: 10.1016/j.peptides.2015.04.002

Abstract

Background: Hyperglycemia is the most important risk factor in the progression of renal fibrosis in diabetic kidney. Based on previous studies, β-casomorphin-7 may exert anti-fibrotic activities in diabetic rats. However, the role of β-casomorphin-7 in the pathogenesis of renal tubulointerstitial fibrosis remains unclear. Thus, this study was designed to investigate the protective effect of β-casomorphin-7 on epithelial-mesenchymal transition (EMT) of NRK-52E cells treated under hyperglycemic condition and to explore the possible mechanism.

Research design and methods: NRK-52E cells were cultured in high glucose (30 mM) for 3 days. Different concentrations of β-casomorphin-7, naloxone (antagonist of opioid receptor) and losartan (antagonist of angiotensin II type I receptor) were added in the culture. Expression of α-smooth muscle actin (α-SMA), E-cadherin, vimentin and cytokeratin19 mRNA were determined by real-time PCR. Protein levels of E-cadherin and α-SMA were analyzed by Western blotting. The concentrations of angiotensin (Ang) II and transforming growth factor β1 (TGF-β1) in the culture medium were determined.

Results: High glucose-induced up-regulation of vimentin mRNA and α-SMA mRNA and protein were significantly inhibited by β-casomorphin-7. On the contrary, high glucose-induced down-regulation of cytokeratin19 mRNA and E-cad mRNA and protein was significantly reversed by β-casomorphin-7. β-casomorphin-7 significantly alleviate high glucose induced increase of AngII and TGF-β1 in the culture. Moreover, losartan significantly attenuated the expression of TGF-β1 and EMT of NRK-52E cells treated under hyperglycemic condition. But naloxone did not affect the EMT of NRK-52E cells treated by high glucose and β-casomorphin-7.

Conclusion: We demonstrate that β-casomorphin-7 has the potential to inhibit high glucose-induced renal proximal tubular EMT partly by modulating AngII-TGF-β1 pathway, but not by opioid receptor.

Keywords: Angiotensin II; Diabetic nephropathy; Epithelial-mesenchymal transdifferentiation; NRK-52E; TGF-β1; β-casomorphin-7.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Angiotensin II / metabolism*
Animals
Cell Line
Endorphins / pharmacology*
Epithelial Cells / drug effects
Epithelial Cells / physiology*
Epithelial-Mesenchymal Transition / drug effects
Epithelial-Mesenchymal Transition / physiology*
Glucose / pharmacology*
Kidney Tubules, Proximal / drug effects
Kidney Tubules, Proximal / physiopathology*
Peptide Fragments / pharmacology*
Rats
Transforming Growth Factor beta1 / metabolism*

Substances

Endorphins
Peptide Fragments
Transforming Growth Factor beta1
Angiotensin II
beta-casomorphin 7
Glucose