A high-performance liquid chromatography(HPLC)method has been developed using a CAPCELL PAK ADME(150 mm×4.6 mm,5μm)as analytical column and a gradient elution with 15 min using acetonitrile and 0.1%(in volume fr...A high-performance liquid chromatography(HPLC)method has been developed using a CAPCELL PAK ADME(150 mm×4.6 mm,5μm)as analytical column and a gradient elution with 15 min using acetonitrile and 0.1%(in volume fraction)phosphoric acid water(pH=2.2)as the mobile phase.Three active substances in cosmetics were quantitatively detected simultaneously at a detection wavelength of 265 nm.The linear ranges of β-nicotinamide mononucleotides,ergothioneine and nicotinamide are 10~200 mg/L,5~100 mg/L and 5~100 mg/L respectively and the detection limits of three components are 3.0 mg/L,1.5 mg/L and 1.5 mg/L respectively.The recovery rate is 97.1~104.9%,with RSD≤2.0%.The method was applied to quantitative analysis of five samples of cosmetics toner,lotion,cream,essence and gel and three samples of raw materials.The results showed that the results of β-nicotinamide mononucleotide and ergothioneine in five cosmetics were consistent with the product label,while nicotinamide was inconsistent with the label.The purity of the three raw material samples was 99.5%,99.7% and 100.8%respectively.This method offers high precision,accuracy and short analysis time,making it a reliable approach for studying three active ingredients in cosmetics and suitable for quality control of related functional ingredients.展开更多
Aging and age-related ailments have emerged as critical challenges and great burdens within the global contemporary society.Addressing these concerns is an imperative task,with the aims of postponing the aging process...Aging and age-related ailments have emerged as critical challenges and great burdens within the global contemporary society.Addressing these concerns is an imperative task,with the aims of postponing the aging process and finding effective treatments for age-related degenerative diseases.Recent investigations have highlighted the significant roles of nicotinamide adenine dinucleotide(NAD+)in the realm of anti-aging.It has been empirically evidenced that supplementation with nicotinamide mononucleotide(NMN)can elevate NAD+levels in the body,thereby ameliorating certain age-related degenerative diseases.The principal anti-aging mechanisms of NMN essentially lie in its impact on cellular energy metabolism,inhibition of cell apoptosis,modulation of immune function,and preservation of genomic stability,which collectively contribute to the deferral of the aging process.This paper critically reviews and evaluates existing research on the anti-aging mechanisms of NMN,elucidates the inherent limitations of current research,and proposes novel avenues for anti-aging investigations.展开更多
Background: Bioenhancers augment the bioavailability of co-administered molecules without showing any significant effect on their own. Piperine, an alkaloid from Piper nigrum, is an established natural bioenhancer. Ni...Background: Bioenhancers augment the bioavailability of co-administered molecules without showing any significant effect on their own. Piperine, an alkaloid from Piper nigrum, is an established natural bioenhancer. Nicotinamide mononucleotide (NMN), an antiaging supplement, is the precursor of coenzyme nicotinamide adenine dinucleotide (NAD) that plays an important role in intracellular redox reactions. Objective: The study compared the serum concentrations of NAD in normal healthy participants, supplemented with NMN 500 mg and NMN 500 mg + 5 mg BioPerine® (95% piperine). Methods: In a randomized, open-label, crossover study, NMN (500 mg) was compared to NMN + BioPerine® (500 mg + 5 mg) in 6 healthy adults, aged 18 - 45 years. The participants received a single oral dose of NMN or NMN + BioPerine® capsules with 240 mL water, and blood samples were collected over 8hr. After a 4-day washout period, the same procedures were repeated as per the crossover design. Total NAD (NADtotal), including oxidized NAD (the oxidized) and its reduced form NADH, was measured in human serum samples. Results: The maximum concentration (Cmax) of NAD in serum was higher with NMN + BioPerine® (282 pmol/mL) compared to NMN (246 pmol/mL) alone. In the presence of BioPerine®, the NAD concentrations reached 257 pmol/mL during the first 2 hr, whereas a comparable serum concentration (246 pmol/mL) was attained only after 6 hr in NMN alone. The AUC0-8hr was 1738 pmol/mL/hr in NMN compared to 2004 pmol/mL/hr in NMN+ BioPerine®. The time to reach peak concentration (t1/2) was similar (6hr) in both groups. No clinically relevant adverse events (AE) were observed, and safety parameters remained within normal ranges in all the participants with both formulations. Conclusion: These results reveal that BioPerine® can effectively increase the NAD concentrations in the serum following NMN supplementation in healthy volunteers. The present study was registered prospectively with the Clinical Trials Registry-India (CTRI/2023/11/059982).展开更多
Background:Elevated ambient temperature-caused heat stress is a major concern for livestock production due to its negative impact on animal feed intake,growth,reproduction,and health.Particularly,the germ cells are ex...Background:Elevated ambient temperature-caused heat stress is a major concern for livestock production due to its negative impact on animal feed intake,growth,reproduction,and health.Particularly,the germ cells are extremely sensitive to the heat stress.However,the effective approach and strategy regarding how to protect mammalian oocytes from heat stress-induced defects have not been determined.Methods:Germinal vesicle(GV)porcine oocytes were cultured at 41.5℃ for 24 h to induce heat stress,and then cultured at 38.5℃ to the specific developmental stage for subsequent analysis.Nicotinamide mononucleotide(NMN)was dissolved in water to 1 mol/L for a stock solution and further diluted with the maturation medium to the final concentrations of 10μmol/L,20μmol/L,50μmol/L or 100μmol/L,respectively,during heat stress.Immunostaining and fluorescence intensity quantification were applied to assess the effects of heat stress and NMN supplementation on the key processes during the oocyte meiotic maturation.Results:Here,we report that NMN supplementation improves the quality of porcine oocytes under heat stress.Specifically,we found that heat stress resulted in oocyte maturation failure by disturbing the dynamics of meiotic organelles,including the cytoskeleton assembly,cortical granule distribution and mitochondrial function.In addition,heat stress induced the production of excessive reactive oxygen species(ROS)and DNA damage,leading to the occurrence of apoptosis in oocytes and subsequent embryonic development arrest.More importantly,we validated that supplementation of NMN during heat stress restored the meiotic defects during porcine oocyte maturation.Conclusions:Taken together,our study documents that NMN supplementation is an effective approach to improve the quality of oocytes under heat stress by promoting both nuclear and cytoplasmic maturation.展开更多
Recent studies have found that nicotinamide mononucleotide(nicotinamide mononucleotide,NMN)also has certain anti-aging,photoprotection,anti-oxidation,and soothing to the skin,while affects the level of nicotinamide ad...Recent studies have found that nicotinamide mononucleotide(nicotinamide mononucleotide,NMN)also has certain anti-aging,photoprotection,anti-oxidation,and soothing to the skin,while affects the level of nicotinamide adenine dinucleotide(nicotinamide adenine dinucleotide,NAD+)to improve aging-related diseases.These skincare features have laid the foundation for its application in cosmetics.NMN has been used in cosmetics and sold on the market in foreign countries,but there have been debates about its safety.It is currently as a new raw material for cosmetics in China,and its safety is also under monitoring.This paper systematically reviewed the basic properties,skin care functions and the safety of its application in cosmetics,aiming to provide theoretical reference for the development and application of NMN.展开更多
BACKGROUND Diabetic nephropathy(DN)is a leading cause of chronic kidney disease and endstage renal disease,and is a significant global healthcare burden.Although proximal tubular epithelial cells(PTECs)and podocytes a...BACKGROUND Diabetic nephropathy(DN)is a leading cause of chronic kidney disease and endstage renal disease,and is a significant global healthcare burden.Although proximal tubular epithelial cells(PTECs)and podocytes are involved in DN progression,the specific molecular interactions between these cells are not well understood.AIM To elucidate the role of interleukin-6(IL-6)/Rab5 signaling in mediating crosstalk between PTECs and podocytes,and to evaluate the protective effects of nicotinamide mononucleotide(NMN)against DN progression.METHODS We utilized in vitro and in vivo models to investigate the pathogenesis of DN.In vitro,human PTECs and murine podocytes were cultured under high-glucose conditions,and IL-6 neutralizing antibodies or NMN treatments were applied.Podocyte injury was assessed by measurements of nephrin endocytosis,Rab5 activity,cytoskeletal organization,cell adhesion,and cell-spreading assays.In vivo,DN was induced in mice using streptozotocin,and mice then received NMN,insulin,or both treatments over an 8-week period.Renal tissues were analyzed histologically,ultrastructurally,and immunochemically,and urinary albumin excretion was measured to assess renal function.Statistical analyses were conducted using one-way ANOVA and Tukey's test.RESULTS High-glucose conditions induced the epithelial-mesenchymal transition(EMT)in PTECs,increased IL-6 secretion,and activated Rab5 signaling in podocytes,leading to increased nephrin endocytosis and podocyte injury.Blocking IL-6 significantly attenuated these effects.NMN treatment of diabetic mice markedly reduced podocyte injury,glomerular hypertrophy,foot-process effacement,and urinary albumin excretion.Mechanistically,NMN suppressed the EMT and IL-6 secretion by PTECs,inhibited Rab5 activation in podocytes,and prevented nephrin endocytosis,thereby preserving the cytoskeletal integrity and function of podocytes.CONCLUSION Our findings reveal a novel pathogenic mechanism of DN in which IL-6 released from glucose-stressed PTECs activates Rab5 signaling in podocytes,followed by nephrin endocytosis and structural injury of podocytes.Importantly,NMN treatment effectively disrupted this pathological pathway of intercellular communication,and provided significant protection against DN progression.These results suggest that NMN supplementation and targeting the IL-6/Rab5 signaling axis has promise as a therapeutic strategy for managing DN.展开更多
Nicotinamide mononucleotide(NMN),as a healthcare product,plays positive effects on the human body.In this study,an engineered Escherichia coli(E.coli)strain was constructed to efficiently produce NMN from glucose and ...Nicotinamide mononucleotide(NMN),as a healthcare product,plays positive effects on the human body.In this study,an engineered Escherichia coli(E.coli)strain was constructed to efficiently produce NMN from glucose and nicotinamide(NAM)through whole-cell biotransformation.First,a highly active nicotinamide phosphoribosyltransferase(NAMPT/NadV)from Vibrio phage KVP40 was screened,which showed the best productivity in catalyzing phosphoribosyl pyrophosphate(PRPP)and NAM to NMN in E.coli.Next,enzymatic activity of E.coli ribose-phosphate diphosphokinase(EcPRS)was improved and its expression level was optimized,which increased the supply of precursor PRPP.The results showed that mutant EcPRS^(D115S) had optimal activity and that the promoter and RBS combination(P_(J23119) and RBS_(III))optimized for EcPRS^(D115S) further accumulated NMN.With the systematic modification,such as the deletion of pfkA and pncC genes,and the expression of Cgzwf^(A243T) and Cggnd^(S361F) genes from Corynebacterium glutamicum,the biosynthesis of NMN was improved.Finally,NMN production was further increased after the introduction of NAM and NMN transporters.The strain ZY17 achieved NMN production of 1.61±0.02 g/L in the shake flask level(OD600=10),and 13.3±0.35 g/L in the 2-L bioreactor with a productivity of 1.11 g/(L.h)and an NAM conversion(α)of 85.3%.In conclusion,we propose a strategy that can effectively enhance the production of NMN in E.coli,which may bring new ideas for the biosynthesis of other nucleotide compounds.展开更多
The interactions between ferric ion and various nucleotides are no doubt very important in the fate of iron in vivo, especially in the process of iron absorption and transportation, as well as to seek potential drugs ...The interactions between ferric ion and various nucleotides are no doubt very important in the fate of iron in vivo, especially in the process of iron absorption and transportation, as well as to seek potential drugs in the treatment of iron-deficiency anemia.展开更多
TRICHOSANTHIN (TCS) is a type Ⅰ ribosome inactivating protein (RIP) with the N-glycosi-dase activity. It removes adenine (ADE) at position A4324 of 28SrRNA. The crystal struc-tural model and the activity of mutants s...TRICHOSANTHIN (TCS) is a type Ⅰ ribosome inactivating protein (RIP) with the N-glycosi-dase activity. It removes adenine (ADE) at position A4324 of 28SrRNA. The crystal struc-tural model and the activity of mutants show that the cleft between two domains is the activitypocket of the N-glycosidase. This provides a solid foundation for the study on relationship be-tween structure and function. Several crystal structures of the complex for exploring the mech-anism of the N-glycosidase have been reported, including TCS/FMP and TCS/ANE complex-es by Yang et al., TCS/NADPH complex by Xiong et al., α MMC/FMP and αMMC/ADE complexes by Ren et al., RTA/FMP and RTA/ApG complexes by Monzingo展开更多
Aim Nicotinamide phosphoribosyltransferase （NAMPT）, also an adipokine known as visfatin, acts via enzymatic activity to synthesize nicotinamide mononucleotide （NMN） and then maintain homeostasis of nicotinam- ide ...Aim Nicotinamide phosphoribosyltransferase （NAMPT）, also an adipokine known as visfatin, acts via enzymatic activity to synthesize nicotinamide mononucleotide （NMN） and then maintain homeostasis of nicotinam- ide adenine dinucleotide （NAD）, which plays a dual role in energy metabolism and biological signaling. Of note, the NAMPT metabolic pathway connects NAD-dependent sirtuin signaling, constituting a strong intrinsic defense system against various stresses. Most recently, we and others have demonstrated several mechanisms by which NAMPT might serve as a therapeutic target against ischemic stroke, including cerebroprotection in the acute phase as well as vascular repair and neurogenesis in the chronic phase. The molecular mechanisms underlying these bene- fits have been explored in vivo and in vitro for neural cells, endothelial progenitor cells, and neural stem cells. Therapeutic interventions using NMN, NAMPT activators and ischemic conditioning are promising for stroke salvage and rehabilitation. Here, we discuss the current NAMPT data in the context of translational efforts for stroke treat- ment.展开更多
Development of the use of favin and nicotinamide-adenine nucleotide fluorescence in monitoringthe redox state of the free mitochondrial NADH/NAD+couple in cels,tissues and organs isreviewed.A break-through was the ide...Development of the use of favin and nicotinamide-adenine nucleotide fluorescence in monitoringthe redox state of the free mitochondrial NADH/NAD+couple in cels,tissues and organs isreviewed.A break-through was the identification of dihydrolipoamide dehydrogenase(FpL)asthe major NAD-linked fluorescent fla voprotein of mitochondria.This mitochondrial matrix fla-voprotein is in equilibriwn with the fre NADH/NAD+pool and its mid-potential is suficientlynear to that of NADH/NAD+so that its percentage reduction follows that of the latter.Pos.sibilities of monitoring mitochondial and cytosolic NADH depend on the population density ofmitochondria and thus are tissue-dependent.Upon a shift toward reduction,fluorescenceintensitis of NADH and flavins swing to reciprocal directions,so that the NADH/favin fluo-rescence ratio can be used to increase the sensitivity of redox monitoring.This method is attainingwidening use in studies on metabolic regulation under normal and pathological conditions.展开更多
A putative chromate ion binding site was identified proximal to a rigidly bound FMN from electron densities in the crystal structure of the quinone reductase from Gluconacetobacter hansenii (Gh-ChrR) (3s2y.pdb). To cl...A putative chromate ion binding site was identified proximal to a rigidly bound FMN from electron densities in the crystal structure of the quinone reductase from Gluconacetobacter hansenii (Gh-ChrR) (3s2y.pdb). To clarify the location of the chromate binding site, and to understand the role of FMN in the NADPH-dependent reduction of chromate, we have expressed and purified four mutant enzymes involving the site-specific substitution of individual side chains within the FMN binding pocket that form non-covalent bonds with the ribityl phosphate (i.e., S15A and R17A in loop 1 between β1 sheet and α1 helix) or the isoalloxanzine ring (E83A or Y84A in loop 4 between the β3 sheet and α4 helix). Mutations that selectively disrupt hydrogen bonds between either the N3 nitrogen on the isoalloxanzine ring (i.e., E83) or the ribitylphos- phoate (i.e., S15) respectively result in 50% or 70% reductions in catalytic rates of chromate reduction. In comparison, mutations that disrupt π-π ring stacking interactions with the isoal-loxanzine ring (i.e., Y84) or a salt bridge with the ribityl phosphate result in 87% and 97% inhibittion. In all cases there are minimal alterations in chromate binding affinities. Collectively, these results support the hypothesis that chromate binds proximal to FMN, and implicate a structural role for FMN positioning for optimal chromate reduction rates. As side chains proximal to the β3/α4 FMN binding loop 4 contribute to both NADH and metal ion binding, we propose a model in which structural changes around the FMN binding pocket couples to both chromate and NADH binding sites.展开更多
Riboflavin （Rf） receptors bind and translocate Rf and its phosphorylated forms （e.g. flavin mononucleotide, FMN） into cells where they mediate various cellular metabolic pathways. Previously, we showed that FMN-co...Riboflavin （Rf） receptors bind and translocate Rf and its phosphorylated forms （e.g. flavin mononucleotide, FMN） into cells where they mediate various cellular metabolic pathways. Previously, we showed that FMN-coated ultrasmall superparamagnetic iron oxide （FLUSPIO） nanoparticles are suitable for labeling metabolically active cancer and endothelial cells in vitro. In this study, we focused on the in vivo application of FLUSPIO using prostate cancer xenografts. Size, charge, and chemical composition of FLUSPIO were evaluated. We explored the in vitro specificity of FLUSPIO for its cellular receptors using magnetic resonance imaging （MRI） and Prussian blue staining. Competitive binding experiments were performed in vivo by injecting free FMN in excess. Bio-distribution of FLUSPIO was determined by estimating iron content in organs and tumors using a colorimetric assay. AFM analysis and zeta potential measurements revealed a particulate morphology approximately 20-40 nm in size and a negative zeta potential （-24.23±0.15 mV） in water. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry data confirmed FMN present on the USPIO nanoparticle surface. FLUSPIO uptake in prostate cancer cells and human umbilical vein endothelial cells was significantly higher than that of control USPIO, while addition of excess of free FMN reduced accumulation. Similarly, in vivo MRI and histology showed specific FLUSPIO uptake by prostate cancer cells, tumor endothelial cells, and tumor-associated macrophages. Besides prominent tumor accumulation, FLUSPIO accumulated in the liver, spleen, lung, and skin. Hence, our data strengthen our hypothesis that targeting riboflavin receptors is an efficient approach to accumulate nanomedicines in tumors opening perspectives for the development of diagnostic and therapeutic systems.展开更多
Objective:This article aims to discuss the distribution of KCNQ1 gene polymorphism in the Chinese Han population in the Huaihai region of China and the correlation between KCNQ1 gene polymorphism and incidence of type...Objective:This article aims to discuss the distribution of KCNQ1 gene polymorphism in the Chinese Han population in the Huaihai region of China and the correlation between KCNQ1 gene polymorphism and incidence of type 2 diabetes(T2DM).Methods:From December 2010 to July 2011,200 T2DM inpatients and outpatients in the Endocrinology Department of the Affiliated Hospital of Xuzhou Medical College were selected as the case group and,200 healthy people identified by the health examination center in the same re-gion were selected as the control group.The polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP)test was used to examine the gene polymorphism of the two groups.Results:(1)Analysis on the control group showed that at the KCNQ1 rC237892 locus,the genotype frequencies of CC,CT and TT were 36.0%(72/200),51.0%(102/200)and 13.0%(26/200)respectively,and the allelic frequencies of C and T were 61.5%(246/400)and 38.5%(154/400)respectively.Analysis on the case group showed the genotype frequencies of CC,CT and TT were 47.5%(95/200),44.0%(88/200)and 8.5%(17/200)respectively,and the allelic frequencies of C and T were 69.5%(278/400)and 30.5%(122/400)respectively.Comparison between the genotype distributions and allelic frequencies of the two tested groups at KCNQ1 rC237892 locus showed differences with statistical significance(P<0.05).(2)Comparison be-tween the genotype distributions and allelic C and A frequencies of the control group and the case group showed differences with no statistical significance(P>0.05).Conclusion:Polymorphism at KCNQ1 rs2237892 locus may be correlated to the incidence of T2DM in the Chinese Han population in Huaihai region of China;polymorphism at rsl51290 locus may be irrelevant to the incidence of T2DM in the Chinese Han population in Huaihai region of China.展开更多
文摘A high-performance liquid chromatography(HPLC)method has been developed using a CAPCELL PAK ADME(150 mm×4.6 mm,5μm)as analytical column and a gradient elution with 15 min using acetonitrile and 0.1%(in volume fraction)phosphoric acid water(pH=2.2)as the mobile phase.Three active substances in cosmetics were quantitatively detected simultaneously at a detection wavelength of 265 nm.The linear ranges of β-nicotinamide mononucleotides,ergothioneine and nicotinamide are 10~200 mg/L,5~100 mg/L and 5~100 mg/L respectively and the detection limits of three components are 3.0 mg/L,1.5 mg/L and 1.5 mg/L respectively.The recovery rate is 97.1~104.9%,with RSD≤2.0%.The method was applied to quantitative analysis of five samples of cosmetics toner,lotion,cream,essence and gel and three samples of raw materials.The results showed that the results of β-nicotinamide mononucleotide and ergothioneine in five cosmetics were consistent with the product label,while nicotinamide was inconsistent with the label.The purity of the three raw material samples was 99.5%,99.7% and 100.8%respectively.This method offers high precision,accuracy and short analysis time,making it a reliable approach for studying three active ingredients in cosmetics and suitable for quality control of related functional ingredients.
文摘Aging and age-related ailments have emerged as critical challenges and great burdens within the global contemporary society.Addressing these concerns is an imperative task,with the aims of postponing the aging process and finding effective treatments for age-related degenerative diseases.Recent investigations have highlighted the significant roles of nicotinamide adenine dinucleotide(NAD+)in the realm of anti-aging.It has been empirically evidenced that supplementation with nicotinamide mononucleotide(NMN)can elevate NAD+levels in the body,thereby ameliorating certain age-related degenerative diseases.The principal anti-aging mechanisms of NMN essentially lie in its impact on cellular energy metabolism,inhibition of cell apoptosis,modulation of immune function,and preservation of genomic stability,which collectively contribute to the deferral of the aging process.This paper critically reviews and evaluates existing research on the anti-aging mechanisms of NMN,elucidates the inherent limitations of current research,and proposes novel avenues for anti-aging investigations.
文摘Background: Bioenhancers augment the bioavailability of co-administered molecules without showing any significant effect on their own. Piperine, an alkaloid from Piper nigrum, is an established natural bioenhancer. Nicotinamide mononucleotide (NMN), an antiaging supplement, is the precursor of coenzyme nicotinamide adenine dinucleotide (NAD) that plays an important role in intracellular redox reactions. Objective: The study compared the serum concentrations of NAD in normal healthy participants, supplemented with NMN 500 mg and NMN 500 mg + 5 mg BioPerine® (95% piperine). Methods: In a randomized, open-label, crossover study, NMN (500 mg) was compared to NMN + BioPerine® (500 mg + 5 mg) in 6 healthy adults, aged 18 - 45 years. The participants received a single oral dose of NMN or NMN + BioPerine® capsules with 240 mL water, and blood samples were collected over 8hr. After a 4-day washout period, the same procedures were repeated as per the crossover design. Total NAD (NADtotal), including oxidized NAD (the oxidized) and its reduced form NADH, was measured in human serum samples. Results: The maximum concentration (Cmax) of NAD in serum was higher with NMN + BioPerine® (282 pmol/mL) compared to NMN (246 pmol/mL) alone. In the presence of BioPerine®, the NAD concentrations reached 257 pmol/mL during the first 2 hr, whereas a comparable serum concentration (246 pmol/mL) was attained only after 6 hr in NMN alone. The AUC0-8hr was 1738 pmol/mL/hr in NMN compared to 2004 pmol/mL/hr in NMN+ BioPerine®. The time to reach peak concentration (t1/2) was similar (6hr) in both groups. No clinically relevant adverse events (AE) were observed, and safety parameters remained within normal ranges in all the participants with both formulations. Conclusion: These results reveal that BioPerine® can effectively increase the NAD concentrations in the serum following NMN supplementation in healthy volunteers. The present study was registered prospectively with the Clinical Trials Registry-India (CTRI/2023/11/059982).
基金supported by the National Natural Science Foundation of China(31900592)the Natural Science Foundation of Jiangsu Province(BK20190526).
文摘Background:Elevated ambient temperature-caused heat stress is a major concern for livestock production due to its negative impact on animal feed intake,growth,reproduction,and health.Particularly,the germ cells are extremely sensitive to the heat stress.However,the effective approach and strategy regarding how to protect mammalian oocytes from heat stress-induced defects have not been determined.Methods:Germinal vesicle(GV)porcine oocytes were cultured at 41.5℃ for 24 h to induce heat stress,and then cultured at 38.5℃ to the specific developmental stage for subsequent analysis.Nicotinamide mononucleotide(NMN)was dissolved in water to 1 mol/L for a stock solution and further diluted with the maturation medium to the final concentrations of 10μmol/L,20μmol/L,50μmol/L or 100μmol/L,respectively,during heat stress.Immunostaining and fluorescence intensity quantification were applied to assess the effects of heat stress and NMN supplementation on the key processes during the oocyte meiotic maturation.Results:Here,we report that NMN supplementation improves the quality of porcine oocytes under heat stress.Specifically,we found that heat stress resulted in oocyte maturation failure by disturbing the dynamics of meiotic organelles,including the cytoskeleton assembly,cortical granule distribution and mitochondrial function.In addition,heat stress induced the production of excessive reactive oxygen species(ROS)and DNA damage,leading to the occurrence of apoptosis in oocytes and subsequent embryonic development arrest.More importantly,we validated that supplementation of NMN during heat stress restored the meiotic defects during porcine oocyte maturation.Conclusions:Taken together,our study documents that NMN supplementation is an effective approach to improve the quality of oocytes under heat stress by promoting both nuclear and cytoplasmic maturation.
文摘Recent studies have found that nicotinamide mononucleotide(nicotinamide mononucleotide,NMN)also has certain anti-aging,photoprotection,anti-oxidation,and soothing to the skin,while affects the level of nicotinamide adenine dinucleotide(nicotinamide adenine dinucleotide,NAD+)to improve aging-related diseases.These skincare features have laid the foundation for its application in cosmetics.NMN has been used in cosmetics and sold on the market in foreign countries,but there have been debates about its safety.It is currently as a new raw material for cosmetics in China,and its safety is also under monitoring.This paper systematically reviewed the basic properties,skin care functions and the safety of its application in cosmetics,aiming to provide theoretical reference for the development and application of NMN.
基金Supported by Hubei Provincial Natural Science Foundation,No.2023AFB732and Scientific Research Project of Hubei Provincial Health Commission,No.WJ2023M053.
文摘BACKGROUND Diabetic nephropathy(DN)is a leading cause of chronic kidney disease and endstage renal disease,and is a significant global healthcare burden.Although proximal tubular epithelial cells(PTECs)and podocytes are involved in DN progression,the specific molecular interactions between these cells are not well understood.AIM To elucidate the role of interleukin-6(IL-6)/Rab5 signaling in mediating crosstalk between PTECs and podocytes,and to evaluate the protective effects of nicotinamide mononucleotide(NMN)against DN progression.METHODS We utilized in vitro and in vivo models to investigate the pathogenesis of DN.In vitro,human PTECs and murine podocytes were cultured under high-glucose conditions,and IL-6 neutralizing antibodies or NMN treatments were applied.Podocyte injury was assessed by measurements of nephrin endocytosis,Rab5 activity,cytoskeletal organization,cell adhesion,and cell-spreading assays.In vivo,DN was induced in mice using streptozotocin,and mice then received NMN,insulin,or both treatments over an 8-week period.Renal tissues were analyzed histologically,ultrastructurally,and immunochemically,and urinary albumin excretion was measured to assess renal function.Statistical analyses were conducted using one-way ANOVA and Tukey's test.RESULTS High-glucose conditions induced the epithelial-mesenchymal transition(EMT)in PTECs,increased IL-6 secretion,and activated Rab5 signaling in podocytes,leading to increased nephrin endocytosis and podocyte injury.Blocking IL-6 significantly attenuated these effects.NMN treatment of diabetic mice markedly reduced podocyte injury,glomerular hypertrophy,foot-process effacement,and urinary albumin excretion.Mechanistically,NMN suppressed the EMT and IL-6 secretion by PTECs,inhibited Rab5 activation in podocytes,and prevented nephrin endocytosis,thereby preserving the cytoskeletal integrity and function of podocytes.CONCLUSION Our findings reveal a novel pathogenic mechanism of DN in which IL-6 released from glucose-stressed PTECs activates Rab5 signaling in podocytes,followed by nephrin endocytosis and structural injury of podocytes.Importantly,NMN treatment effectively disrupted this pathological pathway of intercellular communication,and provided significant protection against DN progression.These results suggest that NMN supplementation and targeting the IL-6/Rab5 signaling axis has promise as a therapeutic strategy for managing DN.
基金supported by the Green Bio-fabrication Program of China(No.2021YFC2100900)the Top-Notch Academic Programs Project of Jiangsu Higher Education Institutions,the 111 Project(Grant No.111–2-06).
文摘Nicotinamide mononucleotide(NMN),as a healthcare product,plays positive effects on the human body.In this study,an engineered Escherichia coli(E.coli)strain was constructed to efficiently produce NMN from glucose and nicotinamide(NAM)through whole-cell biotransformation.First,a highly active nicotinamide phosphoribosyltransferase(NAMPT/NadV)from Vibrio phage KVP40 was screened,which showed the best productivity in catalyzing phosphoribosyl pyrophosphate(PRPP)and NAM to NMN in E.coli.Next,enzymatic activity of E.coli ribose-phosphate diphosphokinase(EcPRS)was improved and its expression level was optimized,which increased the supply of precursor PRPP.The results showed that mutant EcPRS^(D115S) had optimal activity and that the promoter and RBS combination(P_(J23119) and RBS_(III))optimized for EcPRS^(D115S) further accumulated NMN.With the systematic modification,such as the deletion of pfkA and pncC genes,and the expression of Cgzwf^(A243T) and Cggnd^(S361F) genes from Corynebacterium glutamicum,the biosynthesis of NMN was improved.Finally,NMN production was further increased after the introduction of NAM and NMN transporters.The strain ZY17 achieved NMN production of 1.61±0.02 g/L in the shake flask level(OD600=10),and 13.3±0.35 g/L in the 2-L bioreactor with a productivity of 1.11 g/(L.h)and an NAM conversion(α)of 85.3%.In conclusion,we propose a strategy that can effectively enhance the production of NMN in E.coli,which may bring new ideas for the biosynthesis of other nucleotide compounds.
文摘The interactions between ferric ion and various nucleotides are no doubt very important in the fate of iron in vivo, especially in the process of iron absorption and transportation, as well as to seek potential drugs in the treatment of iron-deficiency anemia.
文摘TRICHOSANTHIN (TCS) is a type Ⅰ ribosome inactivating protein (RIP) with the N-glycosi-dase activity. It removes adenine (ADE) at position A4324 of 28SrRNA. The crystal struc-tural model and the activity of mutants show that the cleft between two domains is the activitypocket of the N-glycosidase. This provides a solid foundation for the study on relationship be-tween structure and function. Several crystal structures of the complex for exploring the mech-anism of the N-glycosidase have been reported, including TCS/FMP and TCS/ANE complex-es by Yang et al., TCS/NADPH complex by Xiong et al., α MMC/FMP and αMMC/ADE complexes by Ren et al., RTA/FMP and RTA/ApG complexes by Monzingo
文摘Aim Nicotinamide phosphoribosyltransferase （NAMPT）, also an adipokine known as visfatin, acts via enzymatic activity to synthesize nicotinamide mononucleotide （NMN） and then maintain homeostasis of nicotinam- ide adenine dinucleotide （NAD）, which plays a dual role in energy metabolism and biological signaling. Of note, the NAMPT metabolic pathway connects NAD-dependent sirtuin signaling, constituting a strong intrinsic defense system against various stresses. Most recently, we and others have demonstrated several mechanisms by which NAMPT might serve as a therapeutic target against ischemic stroke, including cerebroprotection in the acute phase as well as vascular repair and neurogenesis in the chronic phase. The molecular mechanisms underlying these bene- fits have been explored in vivo and in vitro for neural cells, endothelial progenitor cells, and neural stem cells. Therapeutic interventions using NMN, NAMPT activators and ischemic conditioning are promising for stroke salvage and rehabilitation. Here, we discuss the current NAMPT data in the context of translational efforts for stroke treat- ment.
文摘Development of the use of favin and nicotinamide-adenine nucleotide fluorescence in monitoringthe redox state of the free mitochondrial NADH/NAD+couple in cels,tissues and organs isreviewed.A break-through was the identification of dihydrolipoamide dehydrogenase(FpL)asthe major NAD-linked fluorescent fla voprotein of mitochondria.This mitochondrial matrix fla-voprotein is in equilibriwn with the fre NADH/NAD+pool and its mid-potential is suficientlynear to that of NADH/NAD+so that its percentage reduction follows that of the latter.Pos.sibilities of monitoring mitochondial and cytosolic NADH depend on the population density ofmitochondria and thus are tissue-dependent.Upon a shift toward reduction,fluorescenceintensitis of NADH and flavins swing to reciprocal directions,so that the NADH/favin fluo-rescence ratio can be used to increase the sensitivity of redox monitoring.This method is attainingwidening use in studies on metabolic regulation under normal and pathological conditions.
文摘A putative chromate ion binding site was identified proximal to a rigidly bound FMN from electron densities in the crystal structure of the quinone reductase from Gluconacetobacter hansenii (Gh-ChrR) (3s2y.pdb). To clarify the location of the chromate binding site, and to understand the role of FMN in the NADPH-dependent reduction of chromate, we have expressed and purified four mutant enzymes involving the site-specific substitution of individual side chains within the FMN binding pocket that form non-covalent bonds with the ribityl phosphate (i.e., S15A and R17A in loop 1 between β1 sheet and α1 helix) or the isoalloxanzine ring (E83A or Y84A in loop 4 between the β3 sheet and α4 helix). Mutations that selectively disrupt hydrogen bonds between either the N3 nitrogen on the isoalloxanzine ring (i.e., E83) or the ribitylphos- phoate (i.e., S15) respectively result in 50% or 70% reductions in catalytic rates of chromate reduction. In comparison, mutations that disrupt π-π ring stacking interactions with the isoal-loxanzine ring (i.e., Y84) or a salt bridge with the ribityl phosphate result in 87% and 97% inhibittion. In all cases there are minimal alterations in chromate binding affinities. Collectively, these results support the hypothesis that chromate binds proximal to FMN, and implicate a structural role for FMN positioning for optimal chromate reduction rates. As side chains proximal to the β3/α4 FMN binding loop 4 contribute to both NADH and metal ion binding, we propose a model in which structural changes around the FMN binding pocket couples to both chromate and NADH binding sites.
文摘Riboflavin （Rf） receptors bind and translocate Rf and its phosphorylated forms （e.g. flavin mononucleotide, FMN） into cells where they mediate various cellular metabolic pathways. Previously, we showed that FMN-coated ultrasmall superparamagnetic iron oxide （FLUSPIO） nanoparticles are suitable for labeling metabolically active cancer and endothelial cells in vitro. In this study, we focused on the in vivo application of FLUSPIO using prostate cancer xenografts. Size, charge, and chemical composition of FLUSPIO were evaluated. We explored the in vitro specificity of FLUSPIO for its cellular receptors using magnetic resonance imaging （MRI） and Prussian blue staining. Competitive binding experiments were performed in vivo by injecting free FMN in excess. Bio-distribution of FLUSPIO was determined by estimating iron content in organs and tumors using a colorimetric assay. AFM analysis and zeta potential measurements revealed a particulate morphology approximately 20-40 nm in size and a negative zeta potential （-24.23±0.15 mV） in water. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry data confirmed FMN present on the USPIO nanoparticle surface. FLUSPIO uptake in prostate cancer cells and human umbilical vein endothelial cells was significantly higher than that of control USPIO, while addition of excess of free FMN reduced accumulation. Similarly, in vivo MRI and histology showed specific FLUSPIO uptake by prostate cancer cells, tumor endothelial cells, and tumor-associated macrophages. Besides prominent tumor accumulation, FLUSPIO accumulated in the liver, spleen, lung, and skin. Hence, our data strengthen our hypothesis that targeting riboflavin receptors is an efficient approach to accumulate nanomedicines in tumors opening perspectives for the development of diagnostic and therapeutic systems.
基金Students Practice and Innovation Training Project of Jiangsu,China in 2011Colleges’Distinctive Discipline Construction Funding Project of Jiangsu,China。
文摘Objective:This article aims to discuss the distribution of KCNQ1 gene polymorphism in the Chinese Han population in the Huaihai region of China and the correlation between KCNQ1 gene polymorphism and incidence of type 2 diabetes(T2DM).Methods:From December 2010 to July 2011,200 T2DM inpatients and outpatients in the Endocrinology Department of the Affiliated Hospital of Xuzhou Medical College were selected as the case group and,200 healthy people identified by the health examination center in the same re-gion were selected as the control group.The polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP)test was used to examine the gene polymorphism of the two groups.Results:(1)Analysis on the control group showed that at the KCNQ1 rC237892 locus,the genotype frequencies of CC,CT and TT were 36.0%(72/200),51.0%(102/200)and 13.0%(26/200)respectively,and the allelic frequencies of C and T were 61.5%(246/400)and 38.5%(154/400)respectively.Analysis on the case group showed the genotype frequencies of CC,CT and TT were 47.5%(95/200),44.0%(88/200)and 8.5%(17/200)respectively,and the allelic frequencies of C and T were 69.5%(278/400)and 30.5%(122/400)respectively.Comparison between the genotype distributions and allelic frequencies of the two tested groups at KCNQ1 rC237892 locus showed differences with statistical significance(P<0.05).(2)Comparison be-tween the genotype distributions and allelic C and A frequencies of the control group and the case group showed differences with no statistical significance(P>0.05).Conclusion:Polymorphism at KCNQ1 rs2237892 locus may be correlated to the incidence of T2DM in the Chinese Han population in Huaihai region of China;polymorphism at rsl51290 locus may be irrelevant to the incidence of T2DM in the Chinese Han population in Huaihai region of China.
