Nagai N, Ito Y. Dysfunction in cytochrome c oxidase caused by excessive nitric oxide in human lens epithelial cells stimulated with interferon-γ and lipopolysaccharide.
Curr Eye Res 2012;
37:889-97. [PMID:
22632269 DOI:
10.3109/02713683.2012.689070]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE
We previously found two mechanisms for the dysfunction in Ca(2+) regulation caused by excessive nitric oxide (NO) using the lenses of hereditary cataract model rats: the first is that NO causes a decrease in Adenosine-5'-triphosphate (ATP) level via cytochrome c oxidase (CCO), resulting in a decrease in ATPase function; the second is that NO causes enhanced lipid peroxidation, resulting in the oxidative inhibition of Ca(2+)-ATPase. In this study, we demonstrate the effect of excessive NO on lipid peroxidation and ATP production in human lens using a human lens epithelial cell line, SRA 01/04 (human lens epithelial (HLE) cells).
METHODS
Excessive NO via inducible NO synthase (iNOS) was induced by stimulating cells with a combination of interferon-gamma (1000 IU IFN-γ) and lipopolysaccharide (100 ng/mL LPS). CCO activity was measured using a Mitochondrial Isolation kit and Cytochrome c Oxidase Assay kit, and ATP levels were determined using a Sigma ATP Bioluminescent Assay Kit and a luminometer AB-2200.
RESULTS
Cytochrome c oxidase activity and ATP levels were decreased in HLE cells stimulated with IFN-γ and LPS, and aminoguanidine (AG) and diethyldithiocarbamate (DDC) added 6 h before cell collection significantly attenuated these decreases in cells stimulated with the IFN-γ and LPS for 24-30 h. However, the lower CCO activity and ATP levels in HLE cells stimulated with the IFN-γ and LPS for 30 h were not changed by treatment with AG or DDC for 6-12 h, while the CCO activity and ATP levels in HLE cells treated with AG or DDC for 18 were recovered.
CONCLUSION
Excessive NO causes a decrease in CCO activity and ATP levels, and the recovery time for CCO activity is related to exposure time to NO in HLE cells.
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