Disruption of endothelial cytoskeleton inhibits high pressure‐induced activation of NADPH oxidase and increases in superoxide production

Abstract

Listen

Translate article

We have demonstrated previously that high vascular pressure increases superoxide production in vascular endothelial and smooth muscle layers via a NADPH oxidase-dependent mechanism. In this study, we further investigated the importance of the endothelial cytoskeleton in pressure-induced activation of NADPH oxidase. Mesenteric arteries were isolated from 12-week-old Wistar rats and cannulated in perfusion chambers. Superoxide production was assessed by the SOD-inhibitable, nitro blue tetrazolium (NBT) reduction assay. Vessels were incubated with NBT (100 μM) at 180 mmHg intravascular pressure, with or without inhibitors, for 60 min. We found that intraluminal administration of nocodazole (1 μM, 60min), an agent that selectively disrups endothelial microtubules, decreased pressure-induced superoxide production by 44%. Intraluminal administration of cytochalasin D (1 μM, 60min), an agent that disrupts microfilaments, reduced pressure-induced superoxide production by 46%. Confocal microscopy confirmed that intraluminal administrations of nocodazole or cytochalasin D selectively disassembled the endothelial cytoskeleton and decreased superoxide production in the endothelial layer of the vessels. These results demonstrate that structural integrity of the endothelial cytoskeleton plays a significant role in pressure-induced activation of endothelial NADPH oxidase and the increased production of superoxide. (Supported by NIH grants HL-43023, HL-68813 and HL-070653)