Proinflammatory phenotype of coronary arteries promotes endothelial apoptosis in aging.
Previously we demonstrated that aging in coronary arteries is associated with proinflammatory phenotypic changes and decreased NO bioavailability, which, we hypothesized, promotes vascular disease by enhancing endothelial apoptosis. To test this hypothesis we characterized proapoptotic alterations in the phenotype of coronary arteries of aged (26 mo old) and young (3 mo old) F344 rats. DNA fragmentation analysis and TUNEL assay showed that in aged vessels there was an approximately fivefold increase in the number of apoptotic endothelial cells. In aged coronary arteries there was an increased expression of TNFalpha, TNFbeta, and caspase 9 (microarray, real-time PCR), as well as increased caspase 9 and caspase 3 activity, whereas expression of TNFR1, TNFalpha-converting enzyme (TACE), Bcl-2, Bcl-X(L), Bid, Bax, caspase 8, and caspase 3 were unchanged. In vessel culture (18 h) incubation of aged coronary arteries with a TNF blocking antibody or the NO donor S-nitroso-penicillamine (SNAP) decreased apoptotic cell death. Incubation of young arteries with exogenous TNFalpha increased caspase 9 activity and elicited endothelial apoptosis, which was attenuated by SNAP. Inhibition of NO synthesis in cultured young coronary arteries also induced apoptotic cell death and potentiated the apoptotic effect of TNFalpha. Thus we propose that age-related upregulation of TNFalpha and caspase 9 and decreased bioavailability of NO promote endothelial apoptosis in coronary arteries that may lead to impaired endothelial function and ischemic heart disease in the elderly.
Csiszar
Anna
A
Department of Physiology, New York Medical College, Valhalla, New York 10595, USA.
Ungvari
Zoltan
Z
Koller
Akos
A
Edwards
John G
JG
Kaley
Gabor
G
D051722:ADAM Proteins; D000072198:ADAM17 Protein; D000375:Aging / Q000235:genetics*; D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D015153:Blotting, Western; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000737:chemistry / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D004247:DNA / Q000276:immunology / Q000378:metabolism; D053938:DNA Fragmentation / Q000235:genetics; D004730:Endothelium, Vascular / Q000737:chemistry / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D020869:Gene Expression Profiling / Q000379:methods; D020287:In Situ Nick-End Labeling / Q000379:methods; D007249:Inflammation / Q000201:enzymology / Q000235:genetics; D008666:Metalloendopeptidases / Q000096:biosynthesis; D009131:Muscle, Smooth, Vascular / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D010641:Phenotype; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011916:Rats, Inbred F344; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D004247:DNA; D051722:ADAM Proteins; D008666:Metalloendopeptidases; D000072198:ADAM17 Protein; C000606464:Adam17 protein, rat