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Effect of glucose and heparin on mesangial alpha 1(IV)COLL and MMP-2/TIMP-2 mRNA expression
C Caenazzo1, S Garbisa, M Onisto
1Institute of Histology and Embriology, Medical School, Padova, Italy.
Abstract:
Mesangial cells are responsible for the synthesis of mesangial matrix as well as its degradation, which is mediated by a number of proteolytic activities, including metalloproteinases (MMPs). Imbalanced matrix protein metabolism may be responsible for mesangial expansion and glomerulosclerosis in diabetic nephropathy. Heparin prevents this complication. In human and murine mesangial cell cultures, RT-PCR was able to detect mRNA expression for a number of molecules involved in the mesangial extracellular matrix turnover: type IV collagen [alpha 1(IV)COLL], MMP-1, MMP-2, MMP-3, MMP-9 and MMP-10, and the tissue inhibitors TIMP-1 and TIMP-2. The expression of mRNA for alpha 1(IV)COLL and MMP-2/TIMP-2 balance was studied in human cells in the presence of high glucose and heparin. mRNAs for all the studied molecules were expressed at different levels. Interestingly, a shift in the balance of alpha 1(IV)COLL, MMP-2 and TIMP-2 was observed in high glucose, which was partially reversed by heparin supplementation. The new equilibrium was mostly due to the down-regulation of type IV collagen expression, rather than further reduction of potential proteolysis. Our data, while extending the list of potential mediators of mesangial matrix catabolism, highlight a molecular mechanism by which the pathogenesis of diabetic nephropathy may be sustained, and at the same time suggest that heparin may have the potential to correct this abnormality.
Insights
Heparin may counteract diabetic nephropathy by restoring the balance of extracellular matrix proteins in mesangial cells. This study reveals how high glucose disrupts matrix turnover and how heparin partially reverses these changes.
Area of Science:
- Nephrology
- Molecular Biology
- Diabetic Complications
Background:
- Mesangial cells regulate extracellular matrix (ECM) turnover.
- Imbalanced ECM metabolism contributes to diabetic nephropathy.
- Heparin is known to prevent diabetic complications.
Purpose of the Study:
- To investigate the expression of ECM turnover molecules in mesangial cells.
- To examine the effect of high glucose and heparin on this balance.
- To elucidate a potential mechanism for heparin's protective role in diabetic nephropathy.
Main Methods:
- Human and murine mesangial cell cultures.
- Reverse transcription polymerase chain reaction (RT-PCR) for mRNA expression analysis.
- Assessment of alpha 1(IV)COLL, MMP-2, and TIMP-2 expression under high glucose and heparin conditions.
Main Results:
- mRNA expression for alpha 1(IV)COLL, MMP-1, MMP-2, MMP-3, MMP-9, MMP-10, TIMP-1, and TIMP-2 was detected.
- High glucose induced an imbalance in alpha 1(IV)COLL and MMP-2/TIMP-2.
- Heparin partially reversed this imbalance, primarily through down-regulation of type IV collagen.
Conclusions:
- The study identifies key molecules involved in mesangial ECM turnover.
- A molecular mechanism for diabetic nephropathy pathogenesis involving ECM imbalance is highlighted.
- Heparin demonstrates potential in correcting aberrant ECM metabolism in diabetic nephropathy.