Journal
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
Volume 283, Issue 5, Pages H2130-H2139Publisher
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajpheart.00196.2002
Keywords
mitochondria; nitric oxide synthase; superoxide anions
Funding
- NIDDK NIH HHS [DK 52783, DK 54602, DK 45462] Funding Source: Medline
Ask authors/readers for more resources
The accumulated ultrastructural and biochemical evidence is highly suggestive of the existence of mitochondrial nitric oxide (NO) synthase (mtNOS), where local production of NO regulates the electron transport along the respiratory chain. Here, the functional competence of mtNOS in situ in a living cell was examined using an intravital fluorescent NO indicator, 4,5-diaminofluorescein, employing a new procedure for loading it into the mitochondria to demonstrate local NO generation in undisrupted endothelial cells and in isolated mitochondria as well as in human embryonic kidney cells stably expressing endothelial NOS. With the use of this approach, we showed that endothelial cells incubated in the presence of high concentration of D-glucose (but not L-glucose) are characterized by the reduced NO synthetic function of mitochondria despite the unaltered abundance of the enzyme. In parallel, mitochondrial generation of superoxide was augmented in endothelial cells incubated in the presence of a high concentration of D-glucose. Both the NO generation and superoxide production in hyperglycemic environment could be restored to control levels by treating cells with a cell-permeable superoxide dismutase mimetic. In addition, enhanced mitochondrial superoxide production could be suppressed with an inhibitor of NOS in stimulated endothelial cells. In conclusion, the data 1) provide direct evidence of mitochondrial NO production in endothelial cells, 2) demonstrate its suppression and enhanced superoxide generation in hyperglycemic environment, and 3) provide evidence that uncoupled mtNOS represents an important source of superoxide anions in endothelial cells incubated in high glucose-containing medium.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available