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Atrial natriuretic peptide attenuates high glucose‐activated transforming growth factor‐β, Smad and collagen synthesis in renal proximal tubular cells
Author(s) -
Lo ChaoSheng,
Chen ZhaoHong,
Hsieh TustyJiuan,
Shin ShyiJang
Publication year - 2007
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.21590
Subject(s) - smad , medicine , endocrinology , transforming growth factor , atrial natriuretic peptide , chemistry , messenger rna , biology , biochemistry , gene
Atrial natriuretic peptide, besides its role in the regulation of volume homeostasis, has been noted to exert cytoprotective effects in several cell types from hypoxia. The present study was performed to explore the effect of ANP on high glucose‐activated transforming growth factor‐beta1 (TGF‐β1), Smad and collagen synthesis in renal proximal epithelial cells. Cultured NRK‐52E cells were divided into five groups: (1) normal glucose (5.5 mM), (2) high glucose (35 mM), (3) D ‐mannitol (29.5 mM), (4) high glucose plus ANP (10 −6 –10 −9 M), and (5) high glucose plus ANP (10 −6 M) and guanylate cyclase inhibitor LY83583 (10 −7 M) groups. Messenger RNA levels of TGF‐β1, Smad2, and collagens were measured by RT‐PCR. ELISA, immunocytochemistry and Western blotting were used to detect protein levels of TGF‐β1, Smad2, phospho‐Smad 2/3 and collagen type 1. We found high glucose to significantly increase mRNA levels of TGF‐β1, Smad 2, collagen types I and III and protein levels of TGF‐β1, phospho‐Smad 2/3 and collagen type 1, but mannitol did not affect their expression. The addition of ANP significantly attenuated high glucose‐enhanced mRNA and protein levels of TGF‐β1, Smad and collagens. LY83583 blocked the influence of ANP on high glucose‐activated TGF‐β1, Smad and collagen synthesis. This is the first study to demonstrate that activation of TGF‐β1, Smad and collagen synthesis stimulated by high glucose can also be inhibited by exogenous ANP in renal tubular epithelial cells. J. Cell. Biochem. 103: 1999–2009, 2008. © 2007 Wiley‐Liss, Inc.