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Nicotinamide mononucleotide (NMN) is one of the key precursors of coenzyme Ⅰ (NAD+). NMN exists widely in a variety of organisms, and β isomer is its active form. Studies have shown that β-NMN plays a key role in a variety of physiological and metabolic processes. As a potential active substance in anti-aging and improving degenerative and metabolic diseases, the application value of β-NMN has been deeply explored, and it is imminent to achieve large-scale production. Biosynthesis has become the preferred method to synthesize β-NMN because of its high stereoselectivity, mild reaction conditions, and fewer by-products. This paper reviews the physiological activity, chemical synthesis as well as biosynthesis of β-NMN, highlighting the metabolic pathways involved in biosynthesis. This review aims to explore the potential of improving the production strategy of β-NMN by using synthetic biology and provide a theoretical basis for the research of metabolic pathways as well as efficient production of β-NMN.
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Nicotinamide Mononucleotide/metabolism , NAD/metabolismABSTRACT
Objective To evaluate the effect and mechanism of nicotinamide mononucleotide (NMN) on ischemia-reperfusion injury (IRI) induced by donor liver after cardiac death in rat models. Methods Rat models of orthotopic liver transplantation were established by "magnetic ring + double cuff" method. SD rats were randomly divided into the sham operation group (Sham group), orthotopic liver transplantation group (OLT group), NMN treatment + orthotopic liver transplantation group (NMN group), NMN+sirtuin-3 (Sirt3) inhibitor (3-TYP) + orthotopic liver transplantation group (NMN+3-TYP group), respectively. Pathological changes and hepatocyte apoptosis of the rats were observed in each group. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were determined. Superoxide dismutase (SOD) and malondialdehyde (MDA) contents in liver tissues were detected. The expression levels of Sirt3, microtubule-associated protein 1 light chain 3 (LC3)Ⅱ, PTEN-induced putative kinase 1 (PINK1), Parkin and translocase of the outer mitochondrial membrane 20 (TOMM20) in liver tissues were measured. Postoperative survival of the rats in each group was analyzed. Results Compared with the Sham group, serum ALT and AST levels were higher in the OLT group. Compared with the OLT group, the levels of ALT and AST were decreased in the NMN group. Compared with the NMN group, the levels of ALT and AST were increased in the NMN +3-TYP group (all P < 0.05). The liver tissue structure of rats in the Sham group was basically normal. In the OLT group, pathological changes, such as evident congestion, vacuolar degeneration and hepatocyte necrosis, were observed in the liver tissues. Compared with the Sham group, Suzuki score and apoptosis rate were higher in the OLT group. Suzuki score and apoptosis rate in the NMN group were lower than those in the OLT group. Suzuki score and apoptosis rate in the NMN+3-TYP group were higher compared with those in the NMN group (all P < 0.05). Compared with the Sham group, the SOD content was decreased, whereas the MDA content was increased in the OLT group. Compared with the OLT group, the SOD content was increased, whereas the MDA content was decreased in the NMN group. Compared with the NMN group, the SOD content was decreased, whereas the MDA content was increased in the NMN+3-TYP group (all P < 0.05). Compared with the Sham group, the relative expression levels of Sirt3 and TOMM20 proteins were down-regulated, whereas those of PINK1, Parkin and LC3Ⅱproteins were up-regulated in the OLT group. Compared with the OLT group, the relative expression levels of Sirt3, PINK1, Parkin and LC3Ⅱproteins were up-regulated, whereas that of TOMM20 protein was down-regulated in the NMN group. Compared with the NMN group, the relative expression levels of PINK1, Parkin and LC3Ⅱproteins were down-regulated, whereas that of TOMM20 protein was up-regulated in the NMN+3-TYP group (all P < 0.05). In the Sham group, the 7 d survival rate of rats was 100%, 50% in the OLT group, 75% in the NMN group and 58% in the NMN+3-TYP group, respectively. Conclusions NMN may enhance the antioxidative capacity of the liver, induce PINK1/Parkin-mediated mitochondrial autophagy, and alleviate IRI of the liver by up-regulating Sirt3, thereby playing a protective role in the donor liver after cardiac death.
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Objective:To evaluate the effect of nicotinamide mononucleotide (NMN) on neurogenesis decline in sleep-deprived infancy rats.Methods:Seventy-eight clean-grade healthy male Sprague-Dawley rats, aged 7 days, weighing 10-15 g, were divided into 3 groups ( n=26 each) using a random number table method: control group (group Con), sleep deprivation group (group SD) and sleep deprivation plus NMN group (group SD+ NMN). Sleep deprivation model was established by gentle stimulation method with a brush (10 h per day) for 14 consecutive days.NMN 500 mg/kg was intraperitoneally injected in group SD+ NMN, while the equal volume of aqua pura was given instead in Con and SD groups.5′-bromo-2′-deoxyuridine (BrdU) 100 mg/kg was intraperitoneally injected immediately after the end of sleep deprivation to label the new-born cells.At 24 h after completion of sleep deprivation, the stem cell pluripotency transcription factor (SOX2) and doublecortin (DCX) positive cells in the hippocampal DG region were counted using immunofluorescence and immunohistochemical methods, and positron emission tomography-computed tomography was used to observe the metabolism of 18F-fluorodeoxyglucose in the hippocampus.At 4 weeks after completion of sleep deprivation, the number of neuronal nuclei antigen (NeuN)/BrdU and glial fibrillary acid protein (GFAP)/BrdU positive cells in hippocampal DG region was recorded using immunofluorescence, and novel object recognition test was performed to evaluate the cognitive function. Results:Compared with group Con, the number of SOX2 and DCX positive cells was significantly reduced, the standard uptake value of glucose in the hippocampus was decreased, the number of NeuN/BrdU and GFAP/BrdU positive cells was reduced, and discrimination index in novel object recognition test was decreased in group SD ( P<0.05). Compared with group SD, the number of SOX2, DCX NeuN/BrdU and GFAP/BrdU positive cells was increased, the standard uptake value of glucose in the hippocampus was increased, and discrimination index in novel object recognition test was increased in group SD+ NMN ( P<0.05). Conclusion:Nicotinamide mononucleotide can promote neurogenesis, thus improving cognitive function, and the mechanism is related to increasing the metabolism of hippocampal glucose in sleep-deprived infancy rats.
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Objective To investigate the effects of Nicotinamide mononucleotide (NMN) on ulcerative colitis induced by dextran sulfate sodium (DSS) in mice. Methods DSS-induced ulcerative colitis mice were used to evaluate the effects of NMN. After NMN administration, the survival time, weight, disease activity index (DAI), colon tissue length and pathological changes of colon tissue slices were observed. Results NMN did not cause significant changes in the survival time, weight, DAI, and intestinal morphology of ulcerative colitis mice. Conclusion NMN has no significant effect on DSS-induced ulcerative colitis mice.
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Objective To study the effect of nicotinamide mononucleotide (NMN) on the mortality of the lipopoly-saccharide (LPS)-induced endotoxic shock mouse model. Methods 10-week-old C57BL/6J male mice were randomly divided into groups, and were injected intraperitoneally (i.p.) with LPS (10 mg/kg) to induce endotoxic shock models. NMN was i.p. injected in three ways: (1) 0.5 h after modeling, doses of 10, 30, 100 and 300 mg/kg; (2) 0.5 h before modeling, doses of 30, 100, 300 and 600 mg/kg; or (3) 0.5 and 12 h after modeling, dose of 300 mg/kg each time. The death times of each group were recorded, and the survival curves were drawn. Results Compared with the solvent control group, NMN at different doses given 0.5 h after or before modeling didn’t improve the survival rate or delay the death time of endotoxic shock mice; But when given at 0.5 and 12 h 300 mg/kg after modeling, NMN accelerated the death of mice and increased the mortality of mice. NMN products by two manufacturers showed similar effects. Conclusion NMN has no therapeutic effect on LPS-induced endotoxic shock, and repeated administration of NMN after endotoxic shock will increase the mortality.
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Objective: To investigate the effect of nicotinamide mononucleotide adenosyl transferase 3 (NMNAT3) on the mitochondrial function and anti-oxidative stress of rabbit bone marrow mesenchymal stem cells (BMSCs) under oxidative stress in vitro by regulating nicotinamide adenine dinucleotide (NAD +) levels. Methods: The bone marrow of femur and tibia of New Zealand white rabbits were extracted. BMSCs were isolated and cultured in vitro by density gradient centrifugation combined with adherent culture. The third generation cells were identified by flow cytometry and multi-directional induction. Overexpression of NMNAT3 gene was transfected into rabbit BMSCs by enhanced green fluorescent protein (EGFP) labeled lentivirus (BMSCs/Lv-NMNAT3-EGFP), and then the expression of NMNAT3 was detected by real-time fluorescence quantitative PCR (qRT-PCR) and Western blot and cell proliferation by cell counting kit 8 (CCK-8) method. BMSCs transfected with negative lentivirus (BMSCs/Lv-EGFP) and untransfected BMSCs were used as controls. The oxidative stress injury cell model was established by using H 2O 2 to treat rabbit BMSCs. According to the experimental treatment conditions, they were divided into 4 groups: Group A was normal BMSCs without H 2O 2 treatment; untransfected BMSCs, BMSCs/Lv-EGFP, and BMSCs/Lv-NMNAT3-EGFP in groups B, C, and D were treated with H 2O 2 simulated oxidative stress, respectively. The effects of NMNAT3 on the mitochondrial function of BMSCs under oxidative stress [changes of mitochondrial membrane potential, NAD + and adenosine triphosphate (ATP) levels], the changes of anti-oxidative stress ability of BMSCs [reactive oxygen species (ROS) and malondialdehyde (MDA) levels, manganese superoxide dismutase (Mn-SOD) and catalase (CAT) activities], and the effects of BMSCs on senescence and apoptosis [senescence associated-β-galactosidase (SA-β-gal) staining and TUNEL staining] were detected after 24 hours of treatment. Results: The rabbit BMSCs were successfully isolated and cultured in vitro. The stable strain of rabbit BMSCs with high expression of NMNAT3 gene was successfully obtained by lentiviral transfection, and the expressions of NMNAT3 gene and protein significantly increased ( P<0.05). There was no significant difference in the trend of cell proliferation compared with normal BMSCs. After treatment with H 2O 2, the function of mitochondria was damaged and apoptosis increased in all groups. However, compared with groups B and C, the group D showed that the mitochondrial function of BMSCs improved, the membrane potential increased, the level of NAD + and ATP synthesis of mitochondria increased; the anti-oxidative stress ability of BMSCs enhanced, the levels of ROS and MDA decreased, and the activities of antioxidant enzymes (Mn-SOD, CAT) increased; and the proportion of SA-β-gal positive cells and the rate of apoptosis decreased. The differences in all indicators between group D and groups B and C were significant ( P<0.05). Conclusion: NMNAT3 can effectively improve the mitochondrial function of rabbit BMSCs via increasing the NAD + levels, and enhance its anti-oxidative stress and improve the survival of BMSCs under oxidative stress conditions.
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BACKGROUND: Studies have shown that bone marrow mesenchymal stem cells (BMSCs) can differentiate into nucleus pulposus-like cells, but the mechanism of differentiation is not clear. OBJECTIVE: To induce bone BMSCs into nucleus pulposus-like cells using Achyranthes bidentata Bl. saponins (ABS) and to explore the role of Nampt/NAD/Sirt1 axis in the differentiation of BMSCs. METHODS: BMSCs were collected from Sprague-Dawley rats. Cells at passage 3 were divided into four groups: BMSCs group, BMSCs+ABS group, BMSCs+ABS+nicotinamide mononucleotide (an exogenous small molecule substance promoting NAD synthesis) group, BMSCs+ABS+FK866 (nicotinamide phosphoribosyltransferase inhibitor) group, in which the cells were induced for 14 days. Alcian blue staining was used to show the changes of glycosaminoglycan in the cells. RT-PCR was used to detect the mRNA expression of COL2, Aggrecan, KRT19, Pax1. The protein expression level of COL2 was detected by western blot. The activity of Sirt1 was detected by Sirt1 assay kit and the content of NAD+ was measured by NAD+/NADH kit. RESULTS AND CONCLUSION: (1) Compared with the BMSCs group, BMSCs+ABS group showed significant increases in the expression levels of glycosaminoglycan, Aggrecan, KRT19, and Pax1 (P < 0.05), and the protein expression levels of COL2, activity of Sirt1, and content of NAD+ were also significantly increased (all P < 0.05). (2) Compared with the BMSCs+ABS group, the above-mentioned indicators were significantly increased in the BMSCs+ABS+nicotinamide mononucleotide (P < 0.05); on the contrary, these indicators were all decreased significantly in the BMSCs+ABS+FK866 group (P < 0.05). To conclude, ABS could induce the differentiation of rat BMSCs into nucleus pulposus-like cells, in which the Nampt/NAD/Sirt1 axis might play a promotion role.
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Objective: To investigate the effect of niacinamide mononucleotide (NMN) on the fibrosis of renal cells in the rats with diabetic nephropathy (DN), and to elucidate the mechanism of NMN in regulating the fibrosis of renal parenchymal cells through silent information regulator 1 (Sirtl) and AKT pathways. Methods: The rat models of type 2 diabetes mellitus were induced by streptozotocin (STZ) and the model rats were randomly divided into experiment group (n= 30) and control group (n=10). The rats in experiment group were divided into diabetes + NMN group (n=15) and diabetes + PBS group (n=15). The rats in diabetes+ NMN group were given subcutaneous injection of NMN for 20 d and the rats in diabetes + PBS group were given 200 μL sterile PBS in the same way. Then the rats were decapitated and the kidney tissues were taken for section and protein extraction. The expression levels of Sirtl, AKT, p-Fox03a and Cav-1 proteins in kidney tissue of the rats in various groups were detected by Western blotting method and immuno-confocal focusing. The glomerular mesangial HBZY-1 cells were treated with high concentration of glucose (200 mmol · L-1) for 3-6 d, and then the cells were further randomly divided into 4 groups (treated with 0, 50, 100, and 200 mmol · L-1 NMN) and the cells only treated with 5. 6 mmol · L-1 glucose were regareded as control group. After 24 h culture, the cells were collected and the expression levels of Sirtl, AKT, and p-Fox03a proteins in the HBZY-1 cells in various groups were detected by Western blotting method. Results: Compared with diabetes +PBS group, the expression levels of Sirtl and AKT proteins in the renal parenchyma cells of the rats in diabetes+ NMN group were significantly increased (P<0. 01) and the expression levels of p-Fox03a and Cav-1 proteins in the renal parenchyma cells of the rats in diabetes + NMN group were also increased (P<0. 01). Compared with control group, the expression levels of Sirtl and AKT proteins in the HBZY-1 cells of the rats in 50 mmol · L-1 NMN group were significantly increased (P<0. 01), and the expression levels of Sirtl, AKT, and p-Fox03a proteins in the HBZY-1 cells in 100 and 200 mmol · L-1 NMN groups were increased significantly (P<0. 05 or P<0. 01). Conclusion: NMN can increase the expression levels of endogenous p-Fox03a and Cav-1 proteins in the glomerular cells of the DN rats by regulating the expression levels of Sirtl and AKT proteins, indicating that NMN and its analogues may play an important role in the prevention and treatment of the renal fibrosis of the DN rats.
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OBJECTIVE Tissue plasminogen activator (tPA) is the only approved pharmaco-logical therapy for acute brain ischaemia;however,a major limitation of tPA is the haemorrhagic trans-formation that follows tPA treatment. Here, we determined whether nicotinamide mononucleotide (NMN), a key intermediate of nicotinamide adenine dinucleotide biosynthesis, affects tPA-induced haemorrhagic transformation. METHODS Middle cerebral artery occlusion (MCAO) was achieved in CD1 mice by introducing a filament to the left MCA for 5 h.When the filament was removed for reperfusion, tPA was infused via the tail vein.A single dose of NMN was injected i.p.(300 mg·kg-1).Mice were killed at 24 h post ischaemia, and their brains were evaluated for brain infarction, oedema, haemoglobin content, apoptosis, neuroinflammation, blood-brain barrier (BBB) permeability, the expression of tight junction proteins(TJPs)and the activity/expression of MMPs. RESULTS In the mice infused with tPA at 5 h post ischaemia, there were significant increases in mortality, brain infarction, brain oedema, brain haemoglobin level, neural apoptosis, Iba-1 staining (microglia activation) and myeloperoxidase staining (neutrophil infiltration). All these tPA-induced alterations were significantly prevented by NMN administration. Mechanistically, the delayed tPA treatment increased BBB permeability by down-regulating TJPs, including claudin-1, occludin and zonula occludens-1,and enhancing the activities and protein expression of MMP9 and MMP2. Similarly, NMN administration partly blocked these tPA-induced molecular changes. CONCLUSION Our results demonstrate that NMN ameliorates tPA-induced haemorrhagic transformation in brain ischaemia by maintaining the integrity of the BBB.
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Objective To investigate the effect and mechanism of interfering the nicotinamide mononucleotide adenylyltransferase 1(NMNAT1)gene in Parkinson's disease(PD)mouse models. Methods Thirty mice were randomly assigned to three groups: the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)group, the small interfering nicotinamide mononucleotide adenylyltransferase 1 (siNMNAT1)+MPTP group, and the control group, with 10 mice in each group.After injecting siRNA-green fluorescent protein(GFP)lentivirals directly into substantia nigra(SN),mice received intraperitoneal injections of MPTP, which was the siNMNAT1 +MPTP group.While the MPTP group was only with injections of MPTP,and the control group was with neither siRNA nor MPTP.Then we assessed the motor coordination ability firstly.To observe the variation of nigrostriatal pathway, the counts of dopamanergic neurons in SN were measured by tyrosine hydroxylase(TH)immunofluorescence staining.And the expression of TH in striatum, which was used to estimate the dopaminergic neurons axonal variation, was analyzed by RT-PCR.Then the expression of TH, SOD1, Bcl2, Bax, Bcl2/Bax in SN was estimated through Western blotting.Results Compared with the control group,the siNMNAT1+MPTP group and the MPTP group decreased significantly in motor coordination ability(creep down time: siNMNAT1 +MPTP group(62.8 ±15.7)s,MPTP group(77.9 ±13.5)s, control group(122.0 ±25.2)s), dopamanergic neuron counts(siNMNAT1 +MPTP group 45.0 ±6.7, MPTP group 68.0 ±11.3, control group 93.0 ± 12.8)and the striatal TH expression(Creep down time: t=-6.291, P=0.000; t=-4.865, P=0.000.Dopamanergic neuron counts:t=-10.482,P=0.000;t=-4.624, P=0.000.TH expression:t=-9.117,P=0.000;t=-5.716, P=0.000).Although the siNMNAT1+MPTP group showed lower coordination ability than the MPTP group, there was no statistically significant difference.Whereas the counts of dopamanergic neurons in SN(t=-5.487, P=0.000), the expression of TH in striatum(t=-5.146,P=0.003),SOD1(t=-4.143, P=0.001)and Bcl2/Bax(t=-6.303, P=0.000)were obviously decreased in the siNMNAT1+MPTP group,in which Bax increased significantly(t=3.550,P=0.002).Conclusions Interfering the expression of NMNAT1 aggravated the neurodegeneration in PD, and the mechanism might be related to oxidative stress and programmed cell death.
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The intracellular parasite Trypanosomacruzi is the aetiological agent of Chagas disease, a public health concern with an increasing incidence rate. This increase is due, among other reasons, to the parasite’s drug resistance mechanisms, which require nicotinamide adenine dinucleotide (NAD+). Furthermore, this molecule is involved in metabolic and intracellular signalling processes necessary for the survival of T. cruzithroughout its life cycle. NAD+biosynthesis is performed by de novo and salvage pathways, which converge on the step that is catalysed by the enzyme nicotinamide mononucleotide adenylyltransferase (NMNAT) (enzyme commission number: 2.7.7.1). The identification of the NMNAT of T. cruziis important for the development of future therapeutic strategies to treat Chagas disease. In this study, a hypothetical open reading frame (ORF) for NMNAT was identified in the genome of T. cruzi.The corresponding putative protein was analysed by simulating structural models. The ORF was amplified from genomic DNA by polymerase chain reaction and was further used for the construction of a corresponding recombinant expression vector. The expressed recombinant protein was partially purified and its activity was evaluated using enzymatic assays. These results comprise the first identification of an NMNAT in T. cruziusing bioinformatics and experimental tools and hence represent the first step to understanding NAD+ metabolism in these parasites.
Subject(s)
Nicotinamide-Nucleotide Adenylyltransferase/metabolism , Trypanosoma cruzi/enzymology , Amino Acid Sequence , Models, Molecular , Molecular Sequence Data , Nicotinamide-Nucleotide Adenylyltransferase/genetics , Sequence AlignmentABSTRACT
Objective To investigate the effect of nicotinamide mononucleotide (NMN) on insulin secretion and gene expressions of pancreatic and duodenal homeobox 1 ( PDX-1 ) and forkhead box-containing protein O-1 ( FoxO1 ),which were important transcription factors for insulin secretion.Methods Insulin secretion level in RIN-m5f cells was detected by rat insulin ELISA detection kit.The mRNA expression levels of PDX-1 and FoxO1 in RIN-m5f cells were analyzed by real-time PCR.The protein expression of PDX-1 was measured by Western blot.Results Insulin secretion levels in RIN-m5f cells treated with repaglinide ( 10 nmol/L) plus NMN ( 100 μnol/L) was significantly higher than those in the blank control,the DMSO control group,and the NMN (50μmol/L) treated group (P ＜0.05 ).The mRNA expression levels of PDX-1 in RIN-m5f cells treated with NMN ( 10,50 and 100 μmol/L) for 36 h were significantly higher than those in the control group (P ＜0.05,P ＜ 0.01,and P ＜ 0.001,respectively).There was marked differences in the mRNA expression levels of PDX-1 among different concentrations of NMN (P ＜0.001 ),but no significant differences in the mRNA expression level of FoxO1 ( P ＞ 0.05).No significant difference was found in the protein expression levels of PDX-1 in RIN-m5f cells treated by NMN (50,100,and 200 μmol/L) for 36 or 48 h compared with the control group (P ＞ 0.05).Conclusion NMN can stimulate insulin secretion and upregulate the mRNA expression of PDX-1 in RIN-m5f cells.