1. Monocyte-derived extracellular Nampt-dependent biosynthesis of NAD(+) protects the heart against pressure overload.
- Author
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Yano M, Akazawa H, Oka T, Yabumoto C, Kudo-Sakamoto Y, Kamo T, Shimizu Y, Yagi H, Naito AT, Lee JK, Suzuki J, Sakata Y, and Komuro I
- Subjects
- Animals, Male, Mice, Mice, Inbred C57BL, Myocardium metabolism, Nicotinamide Mononucleotide metabolism, Sirtuin 1 metabolism, Up-Regulation physiology, Cytokines metabolism, Heart physiology, Monocytes metabolism, NAD biosynthesis, NAD metabolism, Nicotinamide Phosphoribosyltransferase metabolism, Protective Agents chemical synthesis, Protective Agents metabolism
- Abstract
Nicotinamide phosphoribosyltransferase (Nampt) catalyzes the rate-limiting step in the salvage pathway for nicotinamide adenine dinucleotide (NAD(+)) biosynthesis, and thereby regulates the deacetylase activity of sirtuins. Here we show accommodative regulation of myocardial NAD(+) by monocyte-derived extracellular Nampt (eNampt), which is essential for hemodynamic compensation to pressure overload. Although intracellular Nampt (iNampt) expression was decreased in pressure-overloaded hearts, myocardial NAD(+) concentration and Sirt1 activity were preserved. In contrast, iNampt was up-regulated in spleen and monocytes, and circulating eNampt protein and nicotinamide mononucleotide (NMN), a key precursor of NAD(+), were significantly increased. Pharmacological inhibition of Nampt by FK866 or depletion of monocytes/macrophages by clodronate liposomes disrupted the homeostatic mechanism of myocardial NAD(+) levels and NAD(+)-dependent Sirt1 activity, leading to susceptibility to cardiomyocyte apoptosis and cardiac decompensation in pressure-overloaded mice. These biochemical and hemodynamic defects were prevented by systemic administration of NMN. Our studies uncover a crucial role of monocyte-derived eNampt in myocardial adaptation to pressure overload, and highlight a potential intervention controlling myocardial NAD(+) against heart failure.
- Published
- 2015
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