[Modulatory effect of transforming growth factor-beta and Rhein on glucose transporter-1 in human glomerular mesangial cells].

OBJECTIVES

To identify the glucose transporter-1 (GLUT1) in human glomerular mesangial cell and to evaluate the modulatory role of TGF-beta 1 and Rhein on the function of GLUT1 in mesangial cells.

METHODS

GLUT1 in human glomerular mesangial cells was identified by RT-PCR for its mRNA expression. Cell surface protein of GLUT1 had been demonstrated by immunofluorescence staining and flow cytometry analysis using specific antibody. The uptake rate of glucose by mesangial cells was detected using the [3H]-2-DG. Glucose uptake specificity was confirmed by the co-incubation with unlabeled 2-DG or GLUT1 inhibitor Phlorhizin.

RESULTS

Human glomerular mesangial cells expressed functional GLUT1. TGF-beta 1 stimulated [3H]-2-DG uptake and GLUT mRNA expression in mesangial cells. The increase in [3H]-2-DG uptake and GLUT1 mRNA expression by TGF-beta 1 in mesangial cells were markedly abolished by the addition of Rhein in a dose dependent manner, while Rhein showed no effect on the glucose uptake in mesangial cells cultured in normal glucose medium.

CONCLUSIONS

Functional GLUT1 does present in human mesangial cells. TGF-beta 1 stimulates the glucose uptake by enhancing the GLUT1 mRNA expression in mesangial cells. This effect could be antagonized by Rhein. These results suggest that Rhein might be a hopeful drug for patients with diabetic nephropathy.