Premium
Response gene to complement 32 interacts with Smad3 to promote epithelial‐mesenchymal transition of renal tubule cells
Author(s) -
Guo Xia,
Chen ShiYou
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.793.9
Subject(s) - gene knockdown , epithelial–mesenchymal transition , downregulation and upregulation , fibronectin , chemistry , microbiology and biotechnology , small hairpin rna , biology , gene , biochemistry , extracellular matrix
Previous studies have shown that response gene to complement 32 (RGC‐32) mediates TGF‐β‐induced EMT of human renal proximal tubule cells. This study is aimed to elucidate the mechanism underlying RGC‐32 function. RGC‐32 function in EMT appears to be associated with Smad3. Co‐expression of RGC‐32 and Smad3, but not Smad2, induced a higher expression of myofibroblast marker α‐SMA as compared to RGC‐32 or Smad3 alone; knockdown of Smad3 by shRNA blocked RGC‐32‐induced α‐SMA expression. These data suggest that RGC‐32 interacts with Smad3 in the regulation of EMT. RGC‐32 colocalized with Smad3 in the nuclei of renal tubule cells upon TGF‐β induction. Co‐immunoprecipitation assay indicates that Smad3, but not Smad2, physically interacts with RGC‐32 in renal tubular cells. Additional studies showed that RGC‐32 and Smad3 synergistically upregulated α‐SMA promoter activity. Blockade of RGC‐32 significantly inhibited Smad3 activity in activating α‐SMA promoter; knockdown of Smad3 inhibited RGC‐32‐indced α‐SMA mRNA expression. Moreover, RGC‐32 and Smad3 synergistically activated fibronectin while downregulated an epithelial marker E‐cadherin. Mechanistically, RGC‐32 and Smad3 coordinate the induction of EMT by regulating the EMT regulators Slug and Snail. Taken together, our data demonstrate that RGC‐32 interacts with Smad3 in mediating TGF‐β‐induced EMT of human renal tubule cells. (Funding source: NIH R01HL093429)