論文 - 詳細
| RRC ID | 59922 |
|---|---|
| 著者 | Hara N, Osago H, Hiyoshi M, Kobayashi-Miura M, Tsuchiya M. |
| タイトル | Quantitative analysis of the effects of nicotinamide phosphoribosyltransferase induction on the rates of NAD+ synthesis and breakdown in mammalian cells using stable isotope-labeling combined with mass spectrometry. |
| ジャーナル | PLoS One |
| Abstract |
NAD+ is mainly synthesized from nicotinamide (Nam) by the rate-limiting enzyme Nam phosphoribosyltransferase (Nampt) and degraded to Nam by NAD+-degrading enzymes in mammals. Numerous studies report that tissue NAD+ levels decrease during aging and age-related diseases and suggest that NAD+ replenishment promotes healthy aging. Although increased expression of Nampt might be a promising intervention for healthy aging, forced expression of Nampt gene, inducing more than 10-fold increases in the enzyme protein level, has been reported to elevate NAD+ levels only 40-60% in mammalian cells. Mechanisms underlying the limited increases in NAD+ levels remain to be determined. Here we show that Nampt is inhibited in cells and that enhanced expression of Nampt activates NAD+ breakdown. Combined with the measurement of each cell's volume, we determined absolute values (μM/h) of the rates of NAD+ synthesis (RS) and breakdown (RB) using a flux assay with a 2H (D)-labeled Nam, together with the absolute NAD+ concentrations in various mammalian cells including primary cultured cardiomyocytes under the physiological conditions and investigated the relations among total cellular Nampt activity, RS, RB, and the NAD+ concentration. NAD+ concentration was maintained within a narrow range (400-700 μM) in the cells. RS was much smaller than the total Nampt activity, indicating that NAD+ synthesis from Nam in the cells is suppressed. Forced expression of Nampt leading to 6-fold increase in total Nampt activity induced only a 1.6-fold increase in cellular NAD+ concentration. Under the conditions, RS increased by 2-fold, while 2-fold increase in RB was also observed. The small increase in cellular NAD+ concentration is likely due to both inhibited increase in the NAD+ synthesis and the activation of its breakdown. Our findings suggest that cellular NAD+ concentrations do not vary dramatically by the physiological fluctuation of Nampt expression and show the tight link between the NAD+ synthesis and its breakdown. |
| 巻・号 | 14(3) |
| ページ | e0214000 |
| 公開日 | 2019-1-1 |
| DOI | 10.1371/journal.pone.0214000 |
| PII | PONE-D-18-30915 |
| PMID | 30875389 |
| PMC | PMC6420012 |
| MeSH | Animals Cell Size Cells, Cultured Humans Isotope Labeling Kinetics Mice Myocytes, Cardiac / metabolism NAD / biosynthesis NAD / metabolism* Nicotinamide Phosphoribosyltransferase / metabolism* Rats Tandem Mass Spectrometry |
| IF | 2.776 |
| 引用数 | 1 |
| オルトメトリクス指標 |
オルトメトリクス指標項目
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| 最多言及媒体 | X(Twitter) |
| 各媒体での言及数の合計 | 2 |
| 過去6か月間でのオルトメトリクス指標の変動値 | 0.0 |
| リソース情報 | |
| ヒト・動物細胞 | HeLa(RCB0007) 293T(RCB2202) Hep G2(RCB1648) CACO-2(RCB0988) C2C12(RCB0987) |