Rho-kinase mediates hyperglycemia-induced plasminogen activator inhibitor-1 expression in vascular endothelial cells.
BACKGROUND
Elevated levels of plasminogen activator inhibitor-1 (PAI-1) are associated with myocardial infarction and stroke, especially in patients with diabetes. The induction of PAI-1 expression by hyperglycemia involves oxidative stress and protein kinase C (PKC). However, the mechanism by which hyperglycemia increases PAI-1 expression is unknown.


RESULTS
Compared with normoglycemia, exposure of human endothelial cells to hyperglycemia, but not mannitol, increased Rho-kinase activity in a time- and concentration-dependent manner. This increase was inhibited by a PKC inhibitor, GF109203X, and antioxidants N-acetylcysteine (NAC) and reduced form of glutathione (GSH). This correlated with inhibition of hyperglycemia-induced PAI-1 expression by GF109203X, NAC, and GSH. Hyperglycemia-increased PAI-1 mRNA and protein levels were inhibited by Rho-kinase inhibitors hydroxyfasudil and Y27632 and by a dominant-negative mutant of Rho-kinase. The mechanism for this inhibition occurs at the level of gene transcription because Rho-kinase inhibitors repress hyperglycemia-stimulated PAI-1 promoter activity without affecting mRNA stability. Hyperglycemia failed to stimulate Rho-kinase activity and PAI-1 expression in heterozygous ROCK I-knockout murine endothelial cells.


CONCLUSIONS
Hyperglycemia stimulates Rho-kinase activity via PKC- and oxidative stress-dependent pathways, leading to increased PAI-1 gene transcription. These results suggest that inhibition of ROCK I may be a novel therapeutic target for preventing thromboembolic complications of diabetes and cardiovascular disease.
Rikitake
Yoshiyuki
Y
Vascular Medicine Research Unit, Brigham and Women's Hospital and Harvard Medical School, Boston, Mass, USA.
Liao
James K
JK
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D006943:Hyperglycemia / Q000201:enzymology / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D018345:Mice, Knockout; D018384:Oxidative Stress; D017395:Plasminogen Activator Inhibitor 1 / Q000032:analysis / Q000235:genetics*; D011493:Protein Kinase C / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000172:deficiency / Q000378:metabolism*; D020871:RNA Stability; D012333:RNA, Messenger / Q000032:analysis; D054460:rho-Associated Kinases
D000975:Antioxidants; D047908:Intracellular Signaling Peptides and Proteins; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D011493:Protein Kinase C