Atherothrombotic
cardiovascular diseases are the predominant causes of mortality of diabetic patients.
Plasminogen activator inhibitor-1 (PAI-1) is the major physiological inhibitor for fibrinolysis, and it is also implicated in
inflammation and tissue remodeling. Increased levels of
PAI-1 and glycated
low-density lipoprotein (glyLDL) were detected in patients with diabetes. Previous studies in our laboratory demonstrated that heat shock factor-1 (HSF1) is involved in glyLDL-induced
PAI-1 overproduction in vascular endothelial cells (EC). The present study investigated transmembrane signaling mechanisms involved in glyLDL-induced HSF1 and
PAI-1 up-regulation in cultured human vascular EC and
streptozotocin-induced diabetic mice.
Receptor for advanced glycation end products (RAGE) antibody prevented glyLDL-induced increase in the abundance of
PAI-1 in EC. GlyLDL significantly increased the translocation of V-Ha-Ras Harvey rat
sarcoma viral oncogene homologue (H-Ras) from cytoplasm to membrane compared with
LDL.
Farnesyltransferase inhibitor-277 or small interference RNA against H-Ras inhibited glyLDL-induced increases in HSF1 and
PAI-1 in EC. Treatment with
diphenyleneiodonium, a
nicotinamide adenine dinucleotide phosphate oxidase (NOX) inhibitor, blocked glyLDL-induced translocation of H-Ras, elevated abundances of HSF1 and
PAI-1 in EC, and increased release of
hydrogen peroxide from EC. Small interference RNA for p22(
phox) prevented glyLDL-induced expression of NOX2, HSF1, and
PAI-1 in EC. GlyLDL significantly increased V-raf-1 murine
leukemia viral oncogene homolog 1 (Raf-1) phosphorylation. Treatment with Raf-1 inhibitor blocked glyLDL-induced increase of
PAI-1 mRNA in EC. The levels of RAGE, H-Ras, NOX4, HSF1, and
PAI-1 were increased in hearts of
streptozotocin-diabetic mice and positively correlated with plasma
glucose. The results suggest that RAGE, NOX, and H-Ras/Raf-1 are implicated in the up-regulation of HSF1 or
PAI-1 in vascular EC under diabetes-associated metabolic stress.