Lab Anim Res.  2011 Sep;27(3):245-250. 10.5625/lar.2011.27.3.245.

High glucose stimulates the expression of erythropoietin in rat glomerular epithelial cells

• Lim SK
• Park SH

• KMID: 1850052
• DOI: http://doi.org/10.5625/lar.2011.27.3.245

Abstract

It has been reported that the levels of erythropoietin are associated with diabetes mellitus. Glomerular epithelial cells, located in the renal cortex, play an important role in the regulation of kidney function and hyperglycemia-induced cell loss of glomerular epithelial cells is implicated in the onset of diabetic nephropathy. This study investigated the effect of high glucose on erythropoietin and erythropoietin receptor expression in rat glomerular epithelial cells. We found that 25 mM D-glucose, but not mannitol or L-glucose, stimulated erythropoietin mRNA and protein expression in a time dependent manner (>4 h) in rat glomerular epithelial cells. In addition, 25 mM glucose, but not mannitol or L-glucose, also increased the phosphorylation of erythropoietin receptor, suggesting a role for erythropoietin receptor phosphorylation in erythropoietin synthesis. We conclude that high glucose stimulates erythropoietin production and erythropoietin receptor phosphorylation in rat glomerular epithelial cells.

Keyword

Diabetic nephropathy; erythropoietin; glomerular epithelial cells

MeSH Terms

Animals
Diabetes Mellitus
Diabetic Nephropathies
Epithelial Cells
Erythropoietin
Glucose
Kidney
Mannitol
Phosphorylation
Rats
Receptors, Erythropoietin
RNA, Messenger
Erythropoietin
Glucose
Mannitol
RNA, Messenger
Receptors, Erythropoietin

Figure

• 

  Figure 1 Expression of rat podocyte specific markers in cultured glomerular epithelial cells (P) and mesangial cells (M). Podocytes and mesangial cells were cultured without any agents. Podocin and WT1 mRNA (A) expression were analyzed by RT-PCR, and the expression level of Podocin and WT1 protein (B) were determined by immunoblotting analysis.

• 

  Figure 2 Time-dependent effect of high glucose on erythropoietin (EPO) mRNA (A), EPO protein (B), and secreted EPO protein (C) in rat glomerular epithelial cells (GECs). GECs were incubated with 25 mM glucose for different time intervals (1-12 h). EPO mRNA expression was analyzed by RT-PCR. Secreted proteins were precipitated from the culture medium with TCA, and the expression level of EPO protein was determined by immunoblotting analysis. Values are mean±SE of three independent experiments with triplicate dishes. *P<0.05 vs control.

• 

  Figure 3 Dose-dependent and osmotic effects of glucose on erythropoietin (EPO) expression in glomerular epithelial cells (GECs). GECs were incubated with different doses of glucose (0 to 50 mM glucose) for 8 h (A). Osmotic effects of D-glucose, mannitol, and L-glucose on EPO production (B). GECs were incubated with D-glucose, mannitol, or L-glucose (25 mM or 50 mM) for 8 h. Values are mean±SE of three independent experiments with triplicate dishes. *P<0.05 vs control.

• 

  Figure 4 Time-dependent and osmotic effects of high glucose on the phosphorylation of erythropoietin (EPO) receptors in rat glomerular epithelial cells (GECs). GECs were incubated with 25 mM glucose for different time intervals (1-12 h) (A). The level of EPO receptor phosphorylation was determined by immunoblotting analysis. Osmotic effects of D-glucose, mannitol, and L-glucose on EPO phosphorylation (B). GECs were incubated with D-glucose, mannitol, or L-glucose (25 mM or 50 mM) for 8 h. Values are mean±SE of three independent experiments with triplicate dishes. *P<0.05 vs control.

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