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Nicotinamide mononucleotide, an intermediate of NAD+ synthesis, protects the heart from ischemia and reperfusion.

Yamamoto T, Byun J, Zhai P, Ikeda Y, Oka S, Sadoshima J - PLoS ONE (2014)

Bottom Line: The protective effect of NMN was accompanied by decreases in acetylation of FoxO1, but it was not obvious in Sirt1 KO mice, suggesting that the effect of NMN is mediated through activation of Sirt1.The protective effect of CR against I/R injury was not significant in cardiac-specific Sirt1 KO mice, suggesting that the protective effect of CR is in part mediated through the Nampt-Sirt1 pathway.In conclusion, exogenous application of NMN and CR protects the heart by both mimicking IPC and activating Sirt1.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark, New Jersey, United States of America.

ABSTRACT
Nicotinamide phosphoribosyltransferase (Nampt), the rate-limiting enzyme for nicotinamide adenine dinucleotide (NAD+) synthesis, and Sirt1, an NAD+-dependent histone deacetylase, protect the heart against ischemia/reperfusion (I/R). It remains unknown whether Nampt mediates the protective effect of ischemic preconditioning (IPC), whether nicotinamide mononucleotide (NMN, 500 mg/kg), a product of Nampt in the NAD+ salvage pathway, mimics the effect of IPC, or whether caloric restriction (CR) upregulates Nampt and protects the heart through a Sirt1-dependent mechanism. IPC upregulated Nampt protein, and the protective effect of IPC against ischemia (30 minutes) and reperfusion (24 hours) was attenuated at both early and late phases in Nampt +/- mice, suggesting that Nampt plays an essential role in mediating the protective effect of IPC. In order to mimic the effect of Nampt, NMN was administered by intraperitoneal injection. NMN significantly increased the level of NAD+ in the heart at baseline and prevented a decrease in NAD+ during ischemia. NMN protected the heart from I/R injury when it was applied once 30 minutes before ischemia or 4 times just before and during reperfusion, suggesting that exogenous NMN protects the heart from I/R injury in both ischemic and reperfusion phases. The protective effect of NMN was accompanied by decreases in acetylation of FoxO1, but it was not obvious in Sirt1 KO mice, suggesting that the effect of NMN is mediated through activation of Sirt1. Compared to control diet (90% calories), CR (60% calories for 6 weeks) in mice led to a significant reduction in I/R injury, accompanied by upregulation of Nampt. The protective effect of CR against I/R injury was not significant in cardiac-specific Sirt1 KO mice, suggesting that the protective effect of CR is in part mediated through the Nampt-Sirt1 pathway. In conclusion, exogenous application of NMN and CR protects the heart by both mimicking IPC and activating Sirt1.

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Nampt expression is upregulated by ischemic preconditioning (IPC).A, The IPC protocol for wild-type mice. Mice on C57BL/6 background were subjected to 6 cycles of 3 minutes of ischemia plus 3 minutes of reperfusion. Sham groups were subjected to open chest surgery only. Arrows indicate the timing of biochemical analyses. B, Nampt mRNA expression 8 hours and 24 hours after IPC was determined by quantitative RT-PCR. n = 4. C, Nampt protein expression 20 minutes and 24 hours after IPC was determined by Western blot. D, Nampt protein expression with or without IPC in Nampt +/− mice and their wild-type littermates. E-G, Nampt +/− and littermate wild-type mice were subjected to IPC as shown in A. Five minutes or 24 hours after IPC, the mice were subjected to ischemia (30 minutes)/reperfusion (24 hours) (I/R). Some mice were subjected to I/R without IPC. Infarct size/AAR (E), AAR (F) and % reduction in infarct size compared to those without IPC (G) are shown. In E and F, ## p<0.01 vs. wild-type littermates subjected to the same surgery. n = 4 to 8. In G, ## p<0.01 vs. wild-type littermates subjected to I/R 5 minutes after IPC. In B, E, F and G, n.s., not significant; * p<0.05, ** p<0.01.
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pone-0098972-g001: Nampt expression is upregulated by ischemic preconditioning (IPC).A, The IPC protocol for wild-type mice. Mice on C57BL/6 background were subjected to 6 cycles of 3 minutes of ischemia plus 3 minutes of reperfusion. Sham groups were subjected to open chest surgery only. Arrows indicate the timing of biochemical analyses. B, Nampt mRNA expression 8 hours and 24 hours after IPC was determined by quantitative RT-PCR. n = 4. C, Nampt protein expression 20 minutes and 24 hours after IPC was determined by Western blot. D, Nampt protein expression with or without IPC in Nampt +/− mice and their wild-type littermates. E-G, Nampt +/− and littermate wild-type mice were subjected to IPC as shown in A. Five minutes or 24 hours after IPC, the mice were subjected to ischemia (30 minutes)/reperfusion (24 hours) (I/R). Some mice were subjected to I/R without IPC. Infarct size/AAR (E), AAR (F) and % reduction in infarct size compared to those without IPC (G) are shown. In E and F, ## p<0.01 vs. wild-type littermates subjected to the same surgery. n = 4 to 8. In G, ## p<0.01 vs. wild-type littermates subjected to I/R 5 minutes after IPC. In B, E, F and G, n.s., not significant; * p<0.05, ** p<0.01.

Mentions: We examined whether expression of Nampt, the rate-limiting enzyme for NAD+ synthesis in the heart, is regulated by IPC. Mice were subjected to IPC: 6 cycles of 3 min ischemia plus 3 min reperfusion or sham operation (Figure 1A). Nampt mRNA was upregulated 8 hours after IPC, but there was no significant difference between the Nampt mRNA levels of sham and IPC groups 24 hours after IPC, as determined by quantitative RT-PCR (Figure 1B). Nampt protein was upregulated 24 hours after IPC, but there was no significant difference between sham and IPC groups 20 min after IPC (Figure 1C). In order to evaluate the role of Nampt in mediating the cardioprotective effect of IPC, we used systemic Nampt +/− mice (Figure S1 in File S1). At 3 months of age the cardiac phenotype of Nampt+/− mice was not significantly different from that of wild-type mice (Tables S1 and S2 in File S1). We applied ischemia (20 min) followed by 24 hours of reperfusion (I/R) to Nampt+/− and wild type mice either 5 min or 24 hours after IPC. As expected, the level of Nampt protein in the heart was lower in the sham-operated Nampt +/− mice and the upregulation of Nampt observed in wild-type mice 24 hours after IPC was abolished in Nampt +/− mice (Figure 1D). In the wild-type mice subjected to IPC 5 min or 24 hours before I/R, the infarct area was reduced by 63. 9% or 30.4%, respectively, compared to that in mice that received I/R without IPC. In Nampt +/− mice subjected to IPC 5 min or 24 hours before I/R, however, the infarct area was reduced by only 26.3% (p<0.01 vs wild-type mice) or 15.2% (p<0.05 vs wild-type mice), respectively, compared to that in mice that received I/R without IPC (Figure1E-G and Figure S2 in File S1). These results indicate that the cardioprotective effect of IPC against I/R is in part mediated by Nampt.


Nicotinamide mononucleotide, an intermediate of NAD+ synthesis, protects the heart from ischemia and reperfusion.

Yamamoto T, Byun J, Zhai P, Ikeda Y, Oka S, Sadoshima J - PLoS ONE (2014)

Nampt expression is upregulated by ischemic preconditioning (IPC).A, The IPC protocol for wild-type mice. Mice on C57BL/6 background were subjected to 6 cycles of 3 minutes of ischemia plus 3 minutes of reperfusion. Sham groups were subjected to open chest surgery only. Arrows indicate the timing of biochemical analyses. B, Nampt mRNA expression 8 hours and 24 hours after IPC was determined by quantitative RT-PCR. n = 4. C, Nampt protein expression 20 minutes and 24 hours after IPC was determined by Western blot. D, Nampt protein expression with or without IPC in Nampt +/− mice and their wild-type littermates. E-G, Nampt +/− and littermate wild-type mice were subjected to IPC as shown in A. Five minutes or 24 hours after IPC, the mice were subjected to ischemia (30 minutes)/reperfusion (24 hours) (I/R). Some mice were subjected to I/R without IPC. Infarct size/AAR (E), AAR (F) and % reduction in infarct size compared to those without IPC (G) are shown. In E and F, ## p<0.01 vs. wild-type littermates subjected to the same surgery. n = 4 to 8. In G, ## p<0.01 vs. wild-type littermates subjected to I/R 5 minutes after IPC. In B, E, F and G, n.s., not significant; * p<0.05, ** p<0.01.
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pone-0098972-g001: Nampt expression is upregulated by ischemic preconditioning (IPC).A, The IPC protocol for wild-type mice. Mice on C57BL/6 background were subjected to 6 cycles of 3 minutes of ischemia plus 3 minutes of reperfusion. Sham groups were subjected to open chest surgery only. Arrows indicate the timing of biochemical analyses. B, Nampt mRNA expression 8 hours and 24 hours after IPC was determined by quantitative RT-PCR. n = 4. C, Nampt protein expression 20 minutes and 24 hours after IPC was determined by Western blot. D, Nampt protein expression with or without IPC in Nampt +/− mice and their wild-type littermates. E-G, Nampt +/− and littermate wild-type mice were subjected to IPC as shown in A. Five minutes or 24 hours after IPC, the mice were subjected to ischemia (30 minutes)/reperfusion (24 hours) (I/R). Some mice were subjected to I/R without IPC. Infarct size/AAR (E), AAR (F) and % reduction in infarct size compared to those without IPC (G) are shown. In E and F, ## p<0.01 vs. wild-type littermates subjected to the same surgery. n = 4 to 8. In G, ## p<0.01 vs. wild-type littermates subjected to I/R 5 minutes after IPC. In B, E, F and G, n.s., not significant; * p<0.05, ** p<0.01.
Mentions: We examined whether expression of Nampt, the rate-limiting enzyme for NAD+ synthesis in the heart, is regulated by IPC. Mice were subjected to IPC: 6 cycles of 3 min ischemia plus 3 min reperfusion or sham operation (Figure 1A). Nampt mRNA was upregulated 8 hours after IPC, but there was no significant difference between the Nampt mRNA levels of sham and IPC groups 24 hours after IPC, as determined by quantitative RT-PCR (Figure 1B). Nampt protein was upregulated 24 hours after IPC, but there was no significant difference between sham and IPC groups 20 min after IPC (Figure 1C). In order to evaluate the role of Nampt in mediating the cardioprotective effect of IPC, we used systemic Nampt +/− mice (Figure S1 in File S1). At 3 months of age the cardiac phenotype of Nampt+/− mice was not significantly different from that of wild-type mice (Tables S1 and S2 in File S1). We applied ischemia (20 min) followed by 24 hours of reperfusion (I/R) to Nampt+/− and wild type mice either 5 min or 24 hours after IPC. As expected, the level of Nampt protein in the heart was lower in the sham-operated Nampt +/− mice and the upregulation of Nampt observed in wild-type mice 24 hours after IPC was abolished in Nampt +/− mice (Figure 1D). In the wild-type mice subjected to IPC 5 min or 24 hours before I/R, the infarct area was reduced by 63. 9% or 30.4%, respectively, compared to that in mice that received I/R without IPC. In Nampt +/− mice subjected to IPC 5 min or 24 hours before I/R, however, the infarct area was reduced by only 26.3% (p<0.01 vs wild-type mice) or 15.2% (p<0.05 vs wild-type mice), respectively, compared to that in mice that received I/R without IPC (Figure1E-G and Figure S2 in File S1). These results indicate that the cardioprotective effect of IPC against I/R is in part mediated by Nampt.

Bottom Line: The protective effect of NMN was accompanied by decreases in acetylation of FoxO1, but it was not obvious in Sirt1 KO mice, suggesting that the effect of NMN is mediated through activation of Sirt1.The protective effect of CR against I/R injury was not significant in cardiac-specific Sirt1 KO mice, suggesting that the protective effect of CR is in part mediated through the Nampt-Sirt1 pathway.In conclusion, exogenous application of NMN and CR protects the heart by both mimicking IPC and activating Sirt1.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers New Jersey Medical School, Newark, New Jersey, United States of America.

ABSTRACT
Nicotinamide phosphoribosyltransferase (Nampt), the rate-limiting enzyme for nicotinamide adenine dinucleotide (NAD+) synthesis, and Sirt1, an NAD+-dependent histone deacetylase, protect the heart against ischemia/reperfusion (I/R). It remains unknown whether Nampt mediates the protective effect of ischemic preconditioning (IPC), whether nicotinamide mononucleotide (NMN, 500 mg/kg), a product of Nampt in the NAD+ salvage pathway, mimics the effect of IPC, or whether caloric restriction (CR) upregulates Nampt and protects the heart through a Sirt1-dependent mechanism. IPC upregulated Nampt protein, and the protective effect of IPC against ischemia (30 minutes) and reperfusion (24 hours) was attenuated at both early and late phases in Nampt +/- mice, suggesting that Nampt plays an essential role in mediating the protective effect of IPC. In order to mimic the effect of Nampt, NMN was administered by intraperitoneal injection. NMN significantly increased the level of NAD+ in the heart at baseline and prevented a decrease in NAD+ during ischemia. NMN protected the heart from I/R injury when it was applied once 30 minutes before ischemia or 4 times just before and during reperfusion, suggesting that exogenous NMN protects the heart from I/R injury in both ischemic and reperfusion phases. The protective effect of NMN was accompanied by decreases in acetylation of FoxO1, but it was not obvious in Sirt1 KO mice, suggesting that the effect of NMN is mediated through activation of Sirt1. Compared to control diet (90% calories), CR (60% calories for 6 weeks) in mice led to a significant reduction in I/R injury, accompanied by upregulation of Nampt. The protective effect of CR against I/R injury was not significant in cardiac-specific Sirt1 KO mice, suggesting that the protective effect of CR is in part mediated through the Nampt-Sirt1 pathway. In conclusion, exogenous application of NMN and CR protects the heart by both mimicking IPC and activating Sirt1.

Show MeSH
Related in: MedlinePlus