The endothelium-derived hyperpolarizing factor, H2O2, promotes metal-ion efflux in aortic endothelial cells: elemental mapping by a hard X-ray microprobe.
Hydrogen peroxide (H(2)O(2)) is a physiologic oxidant implicated in vascular cell signaling, although little is known about the biochemical consequences of its reaction with endothelial cells. Submicrometer-resolution hard X-ray elemental mapping of cultured porcine aortic endothelial cells (PAEC) has provided data on the global changes for intracellular elemental density within PAEC and indicates an efflux of metal ions and phosphorus from the cytoplasm after H(2)O(2) treatment. The synchrotron-radiation-induced X-ray emission experiments (SRIXE) show that H(2)O(2)-treated cells are irregularly shaped and exhibit blebbing indicative of increased permeability due to the damaged membrane. The SRIXE results suggest that H(2)O(2)-induced damage is largely restricted to the cell membrane as judged by the changes to membrane and cytoplasmic components rather than the cell nucleus. The SRIXE data also provide a mechanism for cell detoxification as the metal-ion efflux resulting from the initial H(2)O(2)-mediated changes to cell membrane potentially limits intracellular metal-mediated redox processes through Fenton-like chemistry. They may also explain the increased levels of these ions in atherosclerotic plaques, regardless of whether they are involved in plaque formation. Finally, the SRIXE data support the notion that cultured endothelial cells exposed to H(2)O(2) respond with enhanced cellular metal-ion efflux into the extracellular space.
Witting
Paul K
PK
Vascular Biology Group, ANZAC Research Institute, Hospital Road, Concord Repatriation General Hospital, Concord, NSW 2139, Australia.
Harris
Hugh H
HH
Rayner
Benjamin S
BS
Aitken
Jade B
JB
Dillon
Carolyn T
CT
Stocker
Roland
R
Lai
Barry
B
Cai
Zhonghou
Z
Lay
Peter A
PA
D000818:Animals; D001685:Biological Factors / Q000494:pharmacology*; D020013:Calcium Signaling / Q000187:drug effects; D002478:Cells, Cultured; D004577:Electron Probe Microanalysis; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D017136:Ion Transport / Q000187:drug effects; D008670:Metals / Q000378:metabolism*; D008954:Models, Biological; D013552:Swine; D017356:Synchrotrons
D001685:Biological Factors; D008670:Metals; C067410:endothelium-dependent hyperpolarization factor; D006861:Hydrogen Peroxide