TitlePlasma membrane-associated endothelial nitric oxide synthase and activity in aging rat aortic vascular endothelia markedly decline with age.
Publication TypeJournal Article
Year of Publication2006
AuthorsSmith AR, Visioli F, Hagen TM
JournalArch Biochem Biophys
Volume454
Issue1
Pagination100-5
Date Published2006 Oct 01
ISSN0003-9861
KeywordsAging, Animals, Cell Membrane, Cells, Cultured, Cytosol, Endothelium, Vascular, Enzyme Activation, Golgi Apparatus, In Vitro Techniques, Male, Nitric Oxide Synthase Type III, Rats, Tissue Distribution
Abstract

The mechanisms leading to the age-related loss of endothelial nitric oxide (NO) and NO-dependent vasodilation remain largely unknown. Freshly isolated endothelium from young (6 months) and old (36 months) F344xBrN rats were analyzed for endothelial nitric oxide synthase (eNOS) protein, its subcellular distribution, and association with regulatory proteins. Results show that both vessel ring vasoreactivity and A23187-induced eNOS activity in isolated endothelial cells significantly (p < or = 0.05) declined with age. Levels of cGMP, a reliable marker for NO bioactivity also declined significantly (p < or = 0.01). However, no change in overall eNOS protein was evident. Subcellular fractionation studies revealed an age-related loss in active, plasma membrane-bound eNOS relative to eNOS in the Golgi/cytosol of the endothelium. Plasma membrane-associated eNOS in aged endothelium was also less complexed with the activating proteins Hsp90 and Akt and more associated with to caveolin-1, which inhibits eNOS activity. These results suggest that age-dependent loss of NO may be partly caused by differences in eNOS subcellular distribution and its association with inhibitory proteins.
DOI10.1016/j.abb.2006.02.017
Alternate JournalArch. Biochem. Biophys.
PubMed ID16982030
Grant ListP01 AT002034-01 / AT / NCCIH NIH HHS / United States
R01 AG17141A / AG / NIA NIH HHS / United States