Abstract
Background:
We tested whether tumor necrosis factor (TNF)-alpha increases arginase expression in endothelial cells as one of the primary mechanisms by which this inflammatory cytokine compromises endothelial function during ischemia-reperfusion (I/R) injury.
Methods and results:
Mouse hearts were subjected to 30 minutes of global ischemia followed by 90 minutes of reperfusion and their vasoactivity before and after I/R was examined in wild-type (WT), tumor necrosis factor knockout (TNF-/-), and TNF 1.6 (TNF++/++) mice. In WT mice, dilation to the endothelium-dependent vasodilator ACh was blunted in I/R compared with sham control. L-arginine or arginase inhibitor NOHA restored NO-mediated coronary arteriolar dilation in WT I/R mice. O2(-) production was reduced by eNOS inhibitor, L-NAME, or NOHA in WT I/R mice. In TNF-/- mice, I/R did not alter Ach-induced vasodilation and O2(-) production compared with sham mice. The increase in arginase expression that occurs during I/R in WT mice was absent in TNF-/- mice. Arginase expression was confined largely to the endothelium and independent of inflammatory cell invasion. Arginase activity was markedly lower in TNF-/-, but higher in WT I/R than that in WT sham mice.
Conclusions:
Our data demonstrate TNF-alpha upregulates expression of arginase in endothelial cells, which leads to O2(-) production then induces endothelial dysfunction in I/R injury.
Publication types
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Comparative Study
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Acetylcholine / pharmacology
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Animals
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Arginase / antagonists & inhibitors
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Arginase / biosynthesis*
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Arginine / analogs & derivatives
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Arginine / metabolism*
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Arginine / pharmacology
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Coronary Vessels / drug effects
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Coronary Vessels / enzymology*
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Coronary Vessels / physiopathology
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Disease Models, Animal
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Endothelium, Vascular / drug effects
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Endothelium, Vascular / enzymology*
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Endothelium, Vascular / physiopathology
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Enzyme Induction
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Enzyme Inhibitors / pharmacology
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Mice
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Mice, Knockout
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Mice, Transgenic
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Myocardial Reperfusion Injury / enzymology
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Myocardial Reperfusion Injury / metabolism*
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Myocardial Reperfusion Injury / physiopathology
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NG-Nitroarginine Methyl Ester / pharmacology
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Neutrophils / enzymology
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Nitric Oxide / metabolism*
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Nitric Oxide Synthase Type II / antagonists & inhibitors
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Nitric Oxide Synthase Type II / metabolism
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Nitric Oxide Synthase Type III
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Peroxidase / metabolism
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RNA, Messenger / metabolism
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Receptors, Tumor Necrosis Factor / genetics
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Receptors, Tumor Necrosis Factor / metabolism
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Superoxides / metabolism
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Tumor Necrosis Factor-alpha / deficiency
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Tumor Necrosis Factor-alpha / genetics
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Tumor Necrosis Factor-alpha / metabolism*
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Vasodilation* / drug effects
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Vasodilator Agents / pharmacology
Substances
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Enzyme Inhibitors
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N(omega)-hydroxynorarginine
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RNA, Messenger
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Receptors, Tumor Necrosis Factor
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Tumor Necrosis Factor-alpha
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Vasodilator Agents
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Superoxides
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Nitric Oxide
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Arginine
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Peroxidase
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Nitric Oxide Synthase Type II
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Nitric Oxide Synthase Type III
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Nos3 protein, mouse
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Arginase
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Acetylcholine
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NG-Nitroarginine Methyl Ester