GLIPR-2 Overexpression in HK-2 Cells Promotes Cell EMT and Migration through ERK1/2 Activation

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.

Dynamic Proteomic Profiling of Extra-Embryonic Endoderm Differentiation in Mouse Embryonic Stem Cells

“…GLIPR2 and FAM129B were both assigned to the differentiation cluster (Fig. D) and have recently been identified as direct transcriptional targets of ERK signaling in HK‐2 cells and human melanoma cells, respectively . This suggests that cells upregulate FGF/MAPK signaling by shutting down negative feedback components during PrE differentiation, thereby ensuring the continuous FGF/MAPK signaling required for PrE differentiation .…”

“…E) along the differentiation time‐course, although phosphorylation levels in established XEN cell lines were lower than after 72 hours of doxycycline exposure. Both GLIPR2 and FAM129B have been implicated in endowing cells with increased motility , suggesting that they provide a link between the dependence of PrE differentiation on FGF/MAPK signaling and acquisition of a motile phenotype upon differentiation along this lineage.…”

Hypoxia Promotes Epithelial - Mesenchymal Transition of Hepatocellular Carcinoma Cells via Inducing GLIPR-2 Expression

“…Previous studies have shown that GLIPR-2 is abundantly increased in PTCs during kidney fibrogenesis [14]. Further more, our previous results demonstrated that GLIPR-2 contributes significantly to EMT in HK-2 cells which has been classified as type 2 EMT [15]. However, whether GLIPR-2 could induce type 3 EMT occured in carcinogenesis needs further investigation.…”

“…Although it is implicated in human brain tumor growth and kidney fibrosis, the precise biological activity remains unknown [14], [20]. Our previous studies have shown that GLIPR-2 was highly expressed in proximal renal tubular epithelial cells in diabetic nephropathy and overexpression of GLIPR-2 in HK-2 cells promotes EMT in vitro via ERK1/2 signaling pathway, which was classified as type 2 EMT involved in renal fibrosis [15]. Therefore, we hypothesized that GLIPR-2 is elevated in the EMT process in carcinogenesis (type 3 EMT) and involved in tumor invasion and metastasis.…”

Differential RNA Expression Profile of Skeletal Muscle Induced by Experimental Autoimmune Myasthenia Gravis in Rats

“…Glipr2 is a signaling molecule, which has not been well-characterized, but is upregulated in sciatic nerve injury from experimental diabetes (Zhang et al, 2015). Glipr2 is involved in transition of epithelial to mesenchymal cells by way of epidermal growth factor signaling pathways (Huang et al, 2013), which are also known to be involved in recovery from muscle injury. Dyrk2 encodes a tyrosine kinase, which negatively regulates growth of cardiac myocytes (Weiss et al, 2013), and the reduced expression of Dyrk2 in EAMG would be expected to promote recovery from injury.…”