Abstract 1628: Apoptosis Signal-Regulating Kinase 1 Mediates Endothelial Cells Senescence in Hyperglycemia Under Protein Kinase C Pathway
Endothelial ageing is accelerated in patients with diabetes. However, the molecular mechanism were unclear. Here, we show that an apoptosis-inducing signal, apoptosis signal-regulating kinase 1 (ASK1) mediates endothelial cell senescence induced by hyperglycemia. Hyperglycemia induced a time-dependent increase in the levels of ASK1 expression and its activity in human umbilical vein ECs (HUVECs). Incubation of ECs under hyperglycemia increased proportion of cells expressing senescence associated beta-galactosidase (SA-beta-gal)-activity. However, transfection with an adenoviral construct including a dominant negative form of ASK1 gene significantly inhibited SA-beta-gal activity induced by hyperglycemia. In addition, infection with an adenoviral construct expressing the constitutively active ASK1 gene directly induced an increase in the levels of SA-beta-gal-activity. Activation of the ASK1 signal also enhanced plasminogen activator inhibitor-1 (PAI-1) expression in HUVECs. Phorbol 12-myristate-13-acetate, a protein kinase C (PKC) agonist, induced activation of ASK1 activity and up-regulation of PAI-1 expression, SA-beta-gal activity and an inhibitor of PKC suppressed ASK1 activation PAI-1 expression and SA-beta-gal activity induced by high glucose. Induction of senescent ECs in aortas and elevation of plasma PAI-1 levels were observed in streptozotocin (STZ)-diabetic mice, whereas these changes induced by STZ were attenuated in ASK1-knockout mice. Our results suggest that hyperglycemia accelerates EC senescence and upregulation of PAI-1 expression through activation of the ASK1 signal. Thus, ASK1 may be a molecular therapeutic target to prevent endothelial ageing and thrombosis in patients with diabetes.