Oxidative stress in diabetes-induced endothelial dysfunction involvement of nitric oxide and protein kinase C.
Reactive oxygen species (ROS) formation plays a major role in diabetes-induced endothelial dysfunction, though the molecular mechanism(s) involved and the contribution of nitric oxide (NO) are still unclear. This study using bovine retinal endothelial cells was aimed at assessing (i) the role of oxygen-dependent vs. NO-dependent oxidative stress in the endothelial cell permeability alterations induced by the diabetic milieu and (ii) whether protein kinase C (PKC) activation ultimately mediates these changes. Superoxide, lipid peroxide, and PKC activity were higher under high glucose (HG) vs. normal glucose throughout the 30 d period. Nitrite/nitrate and endothelial NO synthase levels increased at 1 d and decreased thereafter. Changes in monolayer permeability to 125I-BSA induced by 1 or 30 d incubation in HG or exposure to advanced glycosylation endproduct were reduced by treatment with antioxidants or PKC inhibitors, whereas NO blockade prevented only the effect of 1 d HG. HG-induced changes were mimicked by a PKC activator, a superoxide generating system, an NO and superoxide donor, or peroxynitrite (attenuated by PKC inhibition), but not a NO donor. The short-term effect of HG depends on a combined oxidative and nitrosative stress with peroxynitrite formation, whereas the long-term effect is related to ROS generation; in both cases, PKC ultimately mediates permeability changes.
Pricci
Flavia
F
Laboratory of Metabolism and Pathological Biochemistry, Istituto Superiore di Sanità, Rome, Italy.
Leto
Gaetano
G
Amadio
Lorena
L
Iacobini
Carla
C
Cordone
Samantha
S
Catalano
Stefania
S
Zicari
Alessandra
A
Sorcini
Mariella
M
Di Mario
Umberto
U
Pugliese
Giuseppe
G
D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D003920:Diabetes Mellitus / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology*; D042783:Endothelial Cells / Q000201:enzymology / Q000378:metabolism / Q000473:pathology*; D006861:Hydrogen Peroxide / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D018384:Oxidative Stress; D010539:Permeability; D011493:Protein Kinase C / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012160:Retina
D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D011493:Protein Kinase C