Research Progress on the Application of β-Nicotinamide Mononucleotides in Cosmetics

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.

Nicotinamide mononucleotide supplementation improves the quality of porcine oocytes under heat stress

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.

INVESTIGATIONS OF FT-IR SPECTRA OF IRON(Ⅲ) MONONUCLEOTIDE COMPOUNDS

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.

Mechanism of trichosanthin interaction with mononucleotide

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

NAMPT as a therapeutic target against stroke

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.

From identification of fluorescent flavoproteins to mitochondrial redox indicators in intact tissues

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.

Mutations in FMN binding pocket diminish chromate reduction rates for Gh-ChrR isolated from <i>Gluconacetobacter hansenii</i>

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.

In vivo evaluation of riboflavin receptor targeted fluorescent USPIO in mice with prostate cancer xenografts

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.

Correlation between KCNQ1 gene polymorphism and type 2 diabetes mellitus in Huaihai region of China

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.