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Effect of transforming growth factor β1 on expressions of C/EBPα and relevant nuclear transcription factors of renal tubular epithelial cells

DU Yun-lei, LIU Jian, YING Ji, DAI Qin, XU Li-li,  WANG Wei-ming   

  1. Department of Nephrology， Ruijin Hospital， Shanghai Jiao Tong University School of Medicine， Shanghai 200025， China
  • Online:2015-09-28 Published:2015-09-30
  • Supported by:

    National Natural Science Foundation of China, 30270613, 30771000, 81270782; National Program on Key Basic Research Project of China, “973” Program, 2012CB517701, 2012CB517604; National Key Technology Research and Development Program of China during the “12th Five-Year Plan”， 2011BAI10B00

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Abstract:

Objective  To observe the effect of transforming growth factor β1(TGF-β1) on expressions of CCAAT enhancer binding protein α (C/EBPα) and nuclear transcription factors of peroxisome proliferator-activated receptor γ (PPARγ) and explore the expression of C/EBPα in the process of TGF-β1 induced renal fibrosis and relevant mechanisms. Methods  Human renal tubular epithelial cells (HK-2) were cultured in vitro and stimulated by TGF-β1 of different concentrations (5 and 10 ng/mL) at different time points (0, 4, 12, and 24 h). Total RNA and protein (nucleoprotein and total protein) and supernatant were collected. Changes of expressions of C/EBPα, nuclear transcription factor PPARγ, and epithelial-mesenchymal transition (EMT) related proteins α-SMA and E-cadherin were detected by real-time PCR and Western blotting. The expression level of monocyte chemotactic protein 1(MCP-1) in supernatant was detected by ELISA. Results  The change of C/EBPα level was the same as that of PPARγ level after HK-2 cells were stimulated by TGF-β1 (5 ng/mL) for 24 h. The difference was not statistically significant (P>0.05) and the expression of E-cadherin decreased. The expression of C/EBPα in nucleoprotein decreased remarkably at 12 h and the expression of PPARγ increased at 4 h after HK-2 cells were stimulated by TGF-β1 (10 ng/mL) for 0, 4, 12, and 24 h. The mRNA expressions of E-cadherin, C/EBPα, and PPARγ decreased by 70%, 50%, and 90%, respectively after HK-2 cells were stimulated by TGF-β1 (10 ng/mL) for 12 h (P<0.05). The MCP-1 level increased by 6 and 10.67 times at 12 h and 24 h after HK-2 cells were stimulated by TGF-β1 (10 ng/mL). Conclusion  C/EBPα involves in the renal interstitial fibrosis induced by TGF-β1 and is relevant to inflammatory response and EMT process of the renal interstitial fibrosis.  C/EBPα also interacts with PPARγ and enhances or inhibits the renal interstitial fibrosis.

Key words: transforming growth factor β1； CCAAT enhancer binding protein α, monocyte chemotactic protein 1；peroxisome proliferator-activated receptor γ