Resumen
Reactive oxygen species (ROS) have been implicated in both cell signaling and pathology. A major source of ROS in endothelial cells is NADPH oxidase, which generates superoxide (O2.-) on the extracellular side of the plasma membrane but can result in intracellular signaling. To study possible transmembrane flux of O2.-, pulmonary microvascular endothelial cells were preloaded with the O2 .--sensitive fluorophore hydroethidine (HE). Application of an extracellular bolus of O2.- resulted in rapid and concentration-dependent transient HE oxidation that was followed by a progressive and nonreversible increase in nuclear HE fluorescence. These fluorescence changes were inhibited by superoxide dismutase (SOD), the anion channel blocker DIDS, and selective silencing of the chloride channel-3 (ClC-3) by treatment with siRNA. Extracellular O2.- triggered Ca2+ release in turn triggered mitochondrial membrane potential alterations that were followed by mitochondrial O2.- production and cellular apoptosis. These "signaling" effects of O 2.- were prevented by DIDS treatment, by depletion of intracellular Ca2+ stores with thapsigargin and by chelation of intracellular Ca2+. This study demonstrates that O2 .- flux across the endothelial cell plasma membrane occurs through ClC-3 channels and induces intracellular Ca2+ release, which activates mitochondrial O2.- generation.
Idioma original | English (US) |
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Páginas (desde-hasta) | 2002-2012 |
Número de páginas | 11 |
Publicación | Molecular Biology of the Cell |
Volumen | 18 |
N.º | 6 |
DOI | |
Estado | Published - jun 2007 |
Publicado de forma externa | Sí |
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology