GLIPR-2 overexpression in HK-2 cells promotes cell EMT and migration through ERK1/2 activation

PLoS One. 2013;8(3):e58574. doi: 10.1371/journal.pone.0058574. Epub 2013 Mar 13.

Abstract

The epithelial-to-mesenchymal transition (EMT) of tubular epithelial cells in the adult kidney is one of the key events in renal interstitial fibrosis. Glioma pathogenesis related-2 (GLIPR-2) has been shown to be up-regulated in proximal tubular cells (PTCs) in the fibrotic kidney. However, the biological function of GLIPR-2 remains unknown. In this study, we found that GLIPR-2 expression is elevated in the kidney tissue samples of patients with diabetic nephropathy (DN). Human proximal renal tubular epithelial cells (HK-2 cells) were transfected with pcDNA3.0-GLIPR-2 and selected with G418. To identify the biological function of GLIPR-2, an epithelial-to-mesenchymal transition (EMT) PCR array analysis was performed, and genes that had statistically significantly altered expression levels with more than a two-fold difference compared with the pcDNA3.0-transfected HK-2 cells were considered. Key elements of the EMT process, such as E-cadherin and vimentin, were transcriptionally activated in the pcDNA3.0-GLIPR-2-transfected sublines. In addition, α-SMA gene expression, which is a marker of myofibroblasts, increased in the pcDNA3.0-GLIPR-2-transfected HK-2 cells. The cell migration assay demonstrated that the transfection of HK-2 with GLIPR-2 promoted cell migration following an EMT. Additionally, consistent with the effects of increased EGFR expression levels, we found that the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) was highly elevated in the pcDNA3.0-GLIPR-2-transfected group. Our study demonstrates that GLIPR-2 overexpression in HK-2 cells can potentiate EMT-like processes in this cell type through the ERK1/2 signaling pathway. GLIPR-2 may be responsible for the development of renal fibrosis by increasing the accumulation of interstitial fibroblasts.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Cell Movement*
  • Disease Progression
  • Enzyme Activation
  • Epithelial-Mesenchymal Transition*
  • Fibrosis
  • Gene Expression
  • Humans
  • Kidney Tubules, Proximal / cytology*
  • Kidney Tubules, Proximal / pathology
  • Membrane Proteins / genetics*
  • Mitogen-Activated Protein Kinase 1 / metabolism*
  • Mitogen-Activated Protein Kinase 3 / metabolism*

Substances

  • GLIPR2 protein, human
  • Membrane Proteins
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3

Grants and funding

Contract grant sponsor is the National Natural Science Foundation of China, contract grant number No. 2009ZX10601. The funders had no role in study design,data collection and analysis,decision to publish,or preparation of the manuscript.