Objective: To investigate the effects of overexpression of decorin (DCN), one of the small leucine-rich proteoglycans, on the expression of extracellular matrix molecules in glomerular mesangial and tubular cells.
Methods: Recombinant adenovirus vector containing DCN gene (Ad/DCN) was constructed, and recombinant adenovirus containing LacZ gene (Ad/LacZ) was used as control vector. Rat renal glomerular mesangial cells of the line RMC and tubular cells of the line HK-2 were cultured and divided into following groups: high glucose + Ad/DCN transfection (experimental), high glucose + Ad/LacZ transfection (vector control), high glucose + neutralizing antibody against transforming growth factor (TGF)-beta 1 (positive control), high glucose non-transfection (PBS control), and low glucose culture (normal control) groups. Western blotting was used to detect the protein expression of decorin, TGF-beta 1, collagen type IV, MMP-2, and MMP-9.
Results: The DCN protein expression was low only in the low glucose group, and was up-regulated in other groups, especially in the Ad/DCN group, so as the expression of TGF-beta 1 and collagen type IV, while the ratio of TGF-beta 1 to decorin is increased in both RMC and HK-2 cells. The expression levels of MMP-2 and MMP-9 decreased in the high-glucose-cultured RMC cells and increased in the high-glucose-cultured HK-2 cells, however, adenovirus-mediated transfection of decorin gene reversed all of these changes, and had almost the same effects on reducing the protein expression of TGF-beta 1 collagen type IV, MMP-2, and MMP-9 as anti-TGF-beta 1 antibody.
Conclusion: The agents increasing the decorin expression in mesangial and tubular cells may help prevent the development and progression of diabetic nephropathy. Overexpression of decorin may be a useful tool for developing new therapeutic application for the treatment of diabetic nephropathy.