Effects of glycated protein on the expression of very late antigen 5 (VLA5), a fibronectin receptor, of cultured rat mesangial cells.
Advanced glycosylation end products are believed to play a role in the increase in extracellular matrix in diabetic glomerulosclerosis via a pathway involving a mesangial cell fibronectin receptor. In the present study, I assessed cultured rat mesangial cells for the presence of mRNA for VLA5, one of the fibronectin receptors. Using these cells, I also evaluated the effects of glycated proteins on the expression of VLA5 and fibronectin. Mesangial cells of Wistar rats were cultured in RPMI 1640 containing 20% FCS. The cells were incubated for 72 hr in a medium containing 50 mg/ml of nonglycated BSA or in a medium containing 50 mg/ml glycated BSA (AGE-BSA). Immunostaining and Northern blot analyses showed that the cells incubated with AGE-BSA exhibited a decrease in VLA5 protein and related mRNA, but showed an increase in the synthesis of fibronectin and related mRNA. On the other hand, non-glycated BSA did not induce these changes in the expression of VLA5 or fibronectin in the mesanginal cells. Northern blot analysis for VLA5 mRNA was also conducted using mesangial cells cultured in a medium with a high glucose concentration (30 mM). However, the high glucose condition did not have any effect on the expression of VLA5 protein or related mRNA. These results suggest that glycated proteins may regulate fibronectin synthesis in mesangial cells by modifying the expression of fibronectin receptors, such as the inhibition of VLA5 synthesis that acts as negative feedback of fibronectin synthesis.
2nd Department of Internal Medicine, Shinshu University School of Medicine.
K
K
Yazaki
D000818:Animals; D002478:Cells, Cultured; D003928:Diabetic Nephropathies / Q000209:etiology / Q000378:metabolism; D005920:Glomerular Mesangium / Q000166:cytology / Q000378:metabolism*; D017127:Glycation End Products, Advanced / Q000494:pharmacology / Q000502:physiology*; D008297:Male; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D017469:Receptors, Fibronectin / Q000235:genetics / Q000378:metabolism*
D017127:Glycation End Products, Advanced; D012333:RNA, Messenger; D017469:Receptors, Fibronectin