RECEPTOR-SPECIFIC INCREASE IN EXTRACELLULAR-MATRIX PRODUCTION IN MOUSE MESANGIAL CELLS BY ADVANCED GLYCOSYLATION END-PRODUCTS IS MEDIATED VIA PLATELET-DERIVED GROWTH-FACTOR

Renal disease is one of the most common and severe complications of di abetes mellitus. The hallmark of the disease, glomerulosclerosis, is c haracterized by an accumulation of extracellular matrix in the mesangi al areas, leading to progressive obliteration of the vascular spaces. The role of the metabolic derangements of diabetes mellitus in the dev elopment of these lesions is incompletely understood. One of the conse quences of hyperglycemia is the formation of advanced glycosylation en d products (AGEs), which result from a series of rearrangements second ary to nonenzymatic reaction of glucose with proteins. Specific recept ors for proteins modified by AGEs, present in several cell types, were recently described in human and rat mesangial cells. Furthermore, exp osure of mesangial cells to AGEs was followed by an increase in fibron ectin production. In the present study we show evidence that mouse mes angial cells exhibit an increase in collagen type IV mRNA and peptide synthesis after exposure to AGEs. Antibodies to AGE receptors prevent this increase, indicating that the response is AGE-receptor-mediated. In addition, anti-platelet-derived growth factor abrogates the AGE res ponse, suggesting that platelet-derived growth factor acts as an inter mediate factor. Transcription assay reveals that the elevated mRNA lev els are due to an increase in the transcription rate, rather than to a n increase in the stability of the message. Finally, the mRNAs coding for laminin and heparan sulfate proteoglycan are also increased after exposure to AGE, whereas glyceraldehyde 3-phosphate dehydrogenase mRNA levels remain constant. The increase in extracellular matrix mRNAs se en in the current study suggests that AGE formation in vivo may be one of the metabolic events leading to the development of diabetic glomer ulosclerosis.