Three dinucleotides containing L-isonucleosides at 5＇-end were synthesized by an elegant phosphoramidite one-pot method. Their binding modes with HIV integrase were simulated and their anti-HIV activities in pseudoty...Three dinucleotides containing L-isonucleosides at 5＇-end were synthesized by an elegant phosphoramidite one-pot method. Their binding modes with HIV integrase were simulated and their anti-HIV activities in pseudotyped virus system were examined.展开更多
The inhibition of 5-a reductase type 2(SRD5A2)by finasteride is commonly used for the management of urinary obstruction resulting from benign prostatic enlargement(BPE).Certain BPE patients showing no SRD5A2 protein e...The inhibition of 5-a reductase type 2(SRD5A2)by finasteride is commonly used for the management of urinary obstruction resulting from benign prostatic enlargement(BPE).Certain BPE patients showing no SRD5A2 protein expression are resistant to finasteride therapy.Our previous work showed that methylated cytosine-phosphate-guanine(CpG)islands in the SRD5A2 gene might account for the absence or reduction of SRD5A2 protein expression.Here,we found that the expression of the SRD5A2 protein was variable and that weak expression of the SRD5A2 protein(scored 0-100)occurred in 10.0%(4/40)of benign adult prostates.We showed that the expression of SRD5A2 was negatively correlated with DNA methyltransferase 1(DNMT1)expression.In vitro SRD5A2-negative BPH-1 cells were resistant to finasteride treatment,and SRD5A2 was re-expressed in BPH-1 cells when SRD5A2 was demethylated by 5-Aza-2T-deoxycytidine(5-Aza-CdR)or N-phthalyl-L-tryptophan(RG108).Furthermore,we determined the exact methylation ratios of CpG dinucleotides in a CpG island of SRD5A2 through MassArray quantitative methylation analysis.Ten methylated CpG dinucleotides,including four CpG dinucleotides in the promoter and six CpG dinucleotides in the first exon,were found in a CpG island located from-400 bp to+600 bp in SRD5A2,which might lead to the silencing of SRD5A2 and the absence or reduction of SRD5A2 protein expression.Finasteride cannot exert a therapeutic effect on patients lacking SRD5A2,which may partially account for the resistance to finasteride observed in certain BPE patients.展开更多
Cyclic dinucleotides(CDNs)play important physiological roles in bacteria,mammals and insects as a novel class of signaling molecules.However,the application of CDNs in agricultural pest control has not been reported y...Cyclic dinucleotides(CDNs)play important physiological roles in bacteria,mammals and insects as a novel class of signaling molecules.However,the application of CDNs in agricultural pest control has not been reported yet.To explore the potential bioactivity of CDNs on agricultural pests,we synthesized ten kinds of CDNs containing adenine and guanine bases with different internucleotide linkages(30,30;20,30;20,20).The target CDNs were used to determine the antifeedant and insecticidal activity against common Lepidoptera pests including S.frugiperda,M.separata,and H.armigera.The bioassay tests indicated that 30,30-c-di-AMP showed the highest antifeedant activity(EC50?0.59 mg/L)against M.separata larvae among all the tested CDNs.Regarding insecticidal activity,20,30-c-di-AMP showed higher insecticidal activity against M.separata larvae with LC50 of 55.4 mg/L.RNA-seq further revealed that 30,30-c-di-AMP and 20,30-c-di-AMP exhibited a significant effect on the growth and development process of insects.More importantly,the bioactivity of 30,30-c-di-AMP was also closely correlated with the stimulation of insect immune inflammation.These results indicated that cyclic dinucleotides can affect the normal physiological process of insects,providing a new direction for managing pests.展开更多
Cyclic dinucleotides(CDNs) are known to activate stimulator of interferon genes(STING) and induce type I interferon responses, therefor possess great potentials to be of immunotherapeutic value for cancers and infecti...Cyclic dinucleotides(CDNs) are known to activate stimulator of interferon genes(STING) and induce type I interferon responses, therefor possess great potentials to be of immunotherapeutic value for cancers and infectious diseases. However, the existence of different single nucleotide polymorphism(SNP) of human STING(hSTING) gene poses an obstacle to achieve broad-spectrum activation by CDNs. We reported here the design and synthesis of a total of 36 CDNs, representing all structural variations, that contain four bases(A, G, C, U) and two linkage directions(2′-5′-linked and 3′-5′-linked phosphodiester).Through systematic evaluation of IFN-β induction with a dual-luciferase reporter assay, we discovered that wild type hSTING and two isoforms(HAQ and AQ) showed strong response while hSTING-R232 H and R293 Q exhibited the relatively weak response to CDNs stimulation. For the first time, we found that the c[G(2′,5′)U(2′,5′)] showed excellent activity against all five hSTING variants even equivalent to the endogenous ligand c[G(2′,5′)A(3′,5′)]. Furthermore, we have also demonstrated that 3′-3′CDNs with two 3′-5′ phosphodiesters showed higher serum and hydrolase stability than 2′-2′ CDNs with two 2′-5′ phosphodiesters and 2′-3′ CDNs with one 2′-5′ and one 3′-5′ phosphodiester. It is very interesting to note that 2′-2′ CDNs has been found for the first time to show strong activity. These findings will stimulate our exploration for the new functional role of CDNs, and provide guidelines to design CDNs based hSTING targeted drugs.展开更多
RNase A catalyzes the hydrolysis of ribonucleic acids to form oligonucleotide fragments containing pyrimidineribonucleoside 2’, 3’-cyclic phosphate at the 3’-termini, which are then further hydrolyzed to produce ol...RNase A catalyzes the hydrolysis of ribonucleic acids to form oligonucleotide fragments containing pyrimidineribonucleoside 2’, 3’-cyclic phosphate at the 3’-termini, which are then further hydrolyzed to produce oligonucleotide fragments with 3’ -phosphate group as the final products. This enzyme can also catalyze the formation of internucleotide linkage from pyrimidineribonucleoside 2’, 3’-cyclic phosphate and a nucleoside component with展开更多
Mitochondria are central organelles in cellular metabolism,orchestrating energy production,biosynthetic pathways,and signaling networks.Nicotinamide adenine dinucleotide(NAD+)and its reduced form(NADH)are essential fo...Mitochondria are central organelles in cellular metabolism,orchestrating energy production,biosynthetic pathways,and signaling networks.Nicotinamide adenine dinucleotide(NAD+)and its reduced form(NADH)are essential for mitochondrial metabolism,functioning both as redox coenzymes and as signaling agents that help regulate cellular balance.Thus,while its major role is in energy production,NAD+is widely recognized as a metabolic cofactor and also serves as a substrate for various enzymes involved in cellular signaling,like sirtuins(SIRTs),poly(ADP-ribosyl)polymerases(PARPs),mono(ADP-ribosyl)transferases,and CD38.Sirtuins,a family of NAD+-dependent deacetylases,are critical in this regulatory network.SIRT3 removes acetyl groups from and enhances the activity of key enzymes that participate in fatty acid breakdown,the tricarboxylic acid(TCA)cycle,and the electron transport chain(etc),thereby enhancing mitochondrial efficiency and energy production.Mitochondrial NAD+biosynthesis involves multiple pathways,including the de novo synthesis from tryptophan via the kynurenine and the salvage pathway,which recycles nicotinamide back to NAD+.Moreover,NAD+concentrations influence mitochondrial dynamics such as fusion,fission,and mitophagy,which are essential for preserving mitochondrial integrity and function.NAD+alsomodulates the balance between glycolysis and oxidative phosphorylation,influencing the metabolic flexibility of cells.During NAD+depletion,mainly in metabolic disorders,cells often shift towards anaerobic glycolysis,reducing ATP production efficiency and increasing lactate production.This metabolic shift is associated with various pathophysiological conditions,including insulin resistance,neurodegeneration,and muscle wasting.This reviewexplores themultifaceted functions of NAD+in regulating mitochondrialmetabolism.It highlights the underlying causes and pathological outcomes of disrupted NAD+metabolism while exploring potential therapeutic targets and treatment strategies.展开更多
BACKGROUND Sepsis is a severe illness characterized by systemic and multiorgan reactive responses and damage.However,the impact of sepsis on the bone marrow,particularly on bone marrow mesenchymal stem cells(BMSCs),is...BACKGROUND Sepsis is a severe illness characterized by systemic and multiorgan reactive responses and damage.However,the impact of sepsis on the bone marrow,particularly on bone marrow mesenchymal stem cells(BMSCs),is less reported.BMSCs are critical stromal cells in the bone marrow microenvironment that maintain bone stability and hematopoietic homeostasis;however,the impairment caused by sepsis remains unknown.AIM To investigate the effects of sepsis on BMSCs and the underlying mechanisms.METHODS BMSCs were obtained from healthy donors and patients with sepsis.We compared the self-renewal capacity,differentiation potential,and hematopoietic supportive ability in vitro.Senescence of septic BMSCs was assessed usingβ-galactosidase staining,senescence-associated secretory phenotype,intracellular reactive oxygen species levels,and the expression of P16 and P21.Finally,the changes in septic BMSCs after nicotinamide adenine dinucleotide(NAD)treatment were evaluated.RESULTS Septic BMSCs showed decreased proliferation and self-renewal,bias towards adipogenic differentiation,and weakened osteogenic differentiation.Additionally,hematopoietic supportive capacity declines in sepsis.The levels of aging markers were significantly higher in the septic BMSCs.After NAD treatment,the proliferation capacity of septic BMSCs showed a recovery trend,with increased osteogenic and hematopoietic supportive capacities.Sepsis resulted in decreased expression of sirtuin 3(SIRT3)in BMSCs,whereas NAD treatment restored SIRT3 expression,enhanced superoxide dismutase enzyme activity,reduced intracellular reactive oxygen species levels,maintained mitochondrial stability and function,and ultimately rejuvenated septic BMSCs.CONCLUSION Sepsis accelerates the aging of BMSCs,as evidenced by a decline in self-renewal and osteogenic capabilities,as well as weakened hematopoietic support functions.These deficiencies can be effectively reversed via the NAD/SIRT3/superoxide dismutase pathway.展开更多
BACKGROUND Inhibition of liver fibrosis plays a crucial role in curbing the advancement of chronic disease to cirrhosis and even liver cancer.However,modern medicine currently lacks direct anti-fibrotic drugs.He-He-Sh...BACKGROUND Inhibition of liver fibrosis plays a crucial role in curbing the advancement of chronic disease to cirrhosis and even liver cancer.However,modern medicine currently lacks direct anti-fibrotic drugs.He-He-Shu-Yang formula(HHSY)is a renowned Chinese medicine for the treatment of liver fibrosis.However,its mechanism of action has not been fully unraveled.AIM To explore the efficacy and mechanism of action of HHSY through in vitro and in vivo experiments.METHODS A liver fibrosis rat model(carbon tetrachloride-induced)was treated with low-or high-dose HHSY(10.42 g/kg or 20.84 g/kg)or with colchicine(1 mg/kg)for 9 weeks.In vitro,LX-2 human hepatic stellate cells(HSCs)were activated using transforming growth factor-β1 and subsequently treated with HHSY-containing serum or a nicotinamide adenine dinucleotide phosphate oxidase 4(NOX4)inhibitor.Through high-performance liquid chromatography,histopathology(hematoxylin and eosin,Masson),immunohistochemistry,western blot,and quantitative reverse transcription polymerase chain reaction analyses,we demonstrated that HHSY inhibited HSC activation and suppressed the NOX4/reactive oxygen species(ROS)/nucleotide binding oligomerization domain-like receptor family pyrin domain-containing 3(NLRP3)pathway.RESULTS In vivo,HHSY improved liver function and alleviated liver pathology,including reducing inflammatory cell infiltration,and liver fibrosis in carbon tetrachloride rats.with more significant effects at higher doses.Immunohistochemistry revealed that HHSY could decrease alpha-smooth muscle actin,NOX4,and NLRP3 expression,as well as serum ROS levels(O_(2)-and H_(2)O_(2),P<0.05).Western blot analysis confirmed HHSY also reduced NLRP3 protein levels(P<0.05).In vitro,HHSY at 1.25%or 2.5%reduced the levels of ACTA2 mRNA,NOX4 protein and NOX4 mRNA,ROS production,and NLRP3 and IL-1βmRNA in activated LX-2 cells(P<0.05).CONCLUSION HHSY effectively treats liver fibrosis,likely by inhibiting HSC activation through the NOX4/ROS/NLRP3 pathway.This underscores HHSY’s clinical relevance as a potential therapeutic option for liver fibrosis.展开更多
The study aimed to explore the efficacy and potential mechanisms of a naturally aromatic cyanogenic compound amygdalin(AMY)in treating glucocorticoid(GC)-associated necrosis of the femoral head(GANFH).We demonstrated ...The study aimed to explore the efficacy and potential mechanisms of a naturally aromatic cyanogenic compound amygdalin(AMY)in treating glucocorticoid(GC)-associated necrosis of the femoral head(GANFH).We demonstrated that GC exacerbates the oxidative stress(OS)microenvironment via promoting nicotinamide adenine dinucleotide phosphate oxidase 4(NOX4)expression in human,rat,and mesenchymal stem cells(MSCs)samples,thus generating excessive reactive oxygen species(ROS),leading to increased apoptosis and unbalanced osteolipogenic differentiation.Furthermore,computational docking results revealed that AMY could bind specifically to the predicted binding sites of NOX4.Additionally,AMY ameliorated the OS microenvironment of MSCs via decreasing NOX4 expression and inhibiting NOX4/ROS/p38MAPK signaling,thereby reversing the GC-induced apoptosis and imbalanced osteolipogenic differentiation,and ultimately alleviating GANFH.In summary,we demonstrated for the first time that AMY attenuated apoptosis and maintained osteolipogenic differentiation balance in MSCs via specifically targeting NOX4,inhibiting NOX4/ROS/p38MAPK signaling,thereby treating GANFH.展开更多
A full_length cDNA has been cloned encoding nicotinamide adenine dinucleotide phosphate_specific glutamate dehydrogenase (NADP_GDH) from Chlorella sorokiniana with the RT_PCR method. The complete nucleotide sequence o...A full_length cDNA has been cloned encoding nicotinamide adenine dinucleotide phosphate_specific glutamate dehydrogenase (NADP_GDH) from Chlorella sorokiniana with the RT_PCR method. The complete nucleotide sequence of NADP_GDH gene had 94% homology to the previously reported one . The NADP_GDH gene was constructed into a vector highly expressed in plants. The specific activity of NADP_GDH in transformants was detected, but not in the control plants. All transformed shoots on MS medium containing lower concentration of nitrogen and the transformed seedlings grown in lower concentration of nitrogen vermiculite had higher growth rate and more leaves than the control plants. Transformed leaf discs cultured on MS medium containing different nitrogen concentrations had more chlorophyll contents compared to the controls. These results suggested that exogenous NADP_GDH may enhance the absorption and utilization to ammonium in plants. The increased weight of transformed leaf discs cultured on medium supplemented with different concentrations of phosphinothricin (PPT) was more than that of control discs. 0.5 μg/mL PPT could be used as a selecting drug instead of kanamycin to develop the transformants. These results suggested that the NADP_GDH gene might be used as a new selecting gene in the future research of plant gene engineering.展开更多
C-di-GMP is one kind of second messengers which plays an important role not only in the regulation of various bacterial physiological activities but also in the activation of innate immune response to induce typeⅠint...C-di-GMP is one kind of second messengers which plays an important role not only in the regulation of various bacterial physiological activities but also in the activation of innate immune response to induce typeⅠinterferon in mammalian cells.In this assay,by using one-pot phosphoramidite method,three novel kinds of analogs of c-di-GMP including its phosphorthiates modified by ganciclovir(7 a,7 b,7 c)have been designed and synthesized.The immune-stimulatory results of these c-di-GMP analogs in RAW-Lucia ISG cells indicated that they couldn’t induce the release of typeⅠinterferon,which demonstrated that the intact structure of ribose moieties is very vital for their bioactivity upon the activation of STING signaling pathway.展开更多
The reactions of four different N-（O,O＇-diisopropyl） phosphoamino acids （DIPP-aa）, such as N-phosphoryl-L-α-alanine （DIPP- L-α-Ala）, N-phosphoryl-D-α-alanine （DIPP-D-α-A1a）, N-phosphoryl-β-alanine （DIPP...The reactions of four different N-（O,O＇-diisopropyl） phosphoamino acids （DIPP-aa）, such as N-phosphoryl-L-α-alanine （DIPP- L-α-Ala）, N-phosphoryl-D-α-alanine （DIPP-D-α-A1a）, N-phosphoryl-β-alanine （DIPP-β-A1a） and N-phosphoryl-γ-amino butyric acid （DIPP-γ-Aba）, and four nucleosides, adenosine （A）, guanosine （G）, cytidine （C） and uridine （U）, were studied by electrospray ionization tandem mass spectrometry （ESI-MS/MS） and HPLC/ESI-MS. DIPP-L-α-A1a and DIPP-D-α-A1a produced the same phosphorylated nucleosides, dinucleotides and phosphoroligopeptide. However, DIPP-β-A1a and DIPP-γ-Aba gave no relevant products.展开更多
Deformability of DNA is important for its superhelical folding in the nucleosome and has long been thought to be facilitated by periodic occurrences of certain dinucleotides along the sequences, with the period close ...Deformability of DNA is important for its superhelical folding in the nucleosome and has long been thought to be facilitated by periodic occurrences of certain dinucleotides along the sequences, with the period close to 10.5 bases. This study statistically examines the conformational properties of dinucleotides containing the 10.5 - base periodicity and those without that periodicity through scanning all nucleosome structures provided in PDB. By categorizing performances on the distribution of step parameter values, averaged net values, standard deviations and deformability based on step conformational energies, we give a detailed description as to the deformation preferences correlated with the periodicity for the 10 unique types of dinucleotides and summarize the possible roles of various steps in how they facilitate DNA bending. The results show that the structural properties of dinucleotide steps are influenced to various extents by the periodicity in nucleosomes and some periodic steps have shown a clear tendency to take specific bending or shearing patterns.展开更多
Recent data implicate oxidative stress as a mediator of pulmonary hypertension (PH) and of the associated pathological changes to the pulmonary vasculature and right ventricle (RV). Increases in reactive oxygen specie...Recent data implicate oxidative stress as a mediator of pulmonary hypertension (PH) and of the associated pathological changes to the pulmonary vasculature and right ventricle (RV). Increases in reactive oxygen species (ROS), altered redox state, and elevated oxidant stress have been demonstrated in the lungs and RV of several animal models of PH, including chronic hypoxia, monocrotaline toxicity, caveolin-1 knock-out mouse, and the transgenic Ren2 rat which overexpresses the mouse renin gene. Generation of ROS in these models is derived mostly from the activities of the nicotinamide adenine dinucleotide phosphate oxidases, xanthine oxidase, and uncoupled endothelial nitric oxide synthase. As disease progresses circulating monocytes and bone marrow-derived monocytic progenitor cells are attracted to and accumulate in the pulmonary vasculature. Once established, these inflammatory cells generate ROS and secrete mitogenic and fibrogenic cytokines that induce cell proliferation and fibrosis in the vascular wall resulting in progressive vascular remodeling. Deficiencies in antioxidant enzymes also contribute to pulmonary hypertensive states. Current therapies were developed to improve endothelial function, reduce pulmonary artery pressure, and slow the progression of vascular remodeling in the pulmonary vasculature by targeting deficiencies in either NO (PDE-type 5 inhibition) or PGI 2 (prostacyclin analogs), or excessive synthesis of ET-1 (ET receptor blockers) with the intent to improve patient clinical status and survival. New therapies may slow disease progression to some extent, but long term management has not been achieved and mortality is still high. Although little is known concerning the effects of current pulmonary arterial hypertension treatments on RV structure and function, interest in this area is increasing. Development of therapeutic strategies that simultaneously target pathology in the pulmonary vasculature and RV may be beneficial in reducing mortality associated with RV failure.展开更多
A novel method for predicting hotspots and coldspots using support vector machine （SVM） based on statistical learning theory is developed. This method is applied to published 303 hot and 48 cold open reading frames ...A novel method for predicting hotspots and coldspots using support vector machine （SVM） based on statistical learning theory is developed. This method is applied to published 303 hot and 48 cold open reading frames （ORFs） in Saccharomyces cerevisiae. The sequence features of general dinucleotide abundance and dinucleotide abundance based on codon usage are extracted, and then the data sets are classified with different parameters and kernel functions combined with the method of two-fold cross validation. The result indicates that 87.47% accuracy can be reached when classifying hot and cold ORF sequences with the kernel of radial basis function combined with dinucleotide abundance based on codon usage.展开更多
Nicotinamide adenine dinucleotide phosphate oxidase(NOX) is a multisubunit enzyme complex that utilizes nicotinamide adenine dinucleotide phosphate to produce superoxide anions and other reactive oxygen species. Under...Nicotinamide adenine dinucleotide phosphate oxidase(NOX) is a multisubunit enzyme complex that utilizes nicotinamide adenine dinucleotide phosphate to produce superoxide anions and other reactive oxygen species. Under normal circumstances, reactive oxygen species mediate a number of important cellular functions, including the facilitation of adaptive immunity. In pathogenic circumstances, however,excess reactive oxygen species generated by NOX promotes apoptotic cell death. In ischemic stroke, in particular, it has been shown that both NOX activation and derangements in glucose metabolism result in increased apoptosis. Moreover, recent studies have established that glucose, as a NOX substrate, plays a vital role in the pathogenesis of reperfusion injury. Thus, NOX inhibition has the potential to mitigate the deleterious impact of hyperglycemia on stroke. In this paper, we provide an overview of this research,coupled with a discussion of its implications for the development of NOX inhibition as a strategy for the treatment of ischemic stroke. Both inhibition using apocynin, as well as the prospect of developing more specific inhibitors based on what is now understood of the biology of NOX assembly and activation, will be highlighted in the course of our discussion.展开更多
Aim:To investigate the impact of abnormal sperm morphology using the sperm deformity index (SDI) on reactive oxygen species (ROS) production and its correlation with sperm DNA damage.Methods:Semen samples were collect...Aim:To investigate the impact of abnormal sperm morphology using the sperm deformity index (SDI) on reactive oxygen species (ROS) production and its correlation with sperm DNA damage.Methods:Semen samples were collected from men undergoing infertility screening (n=7) and healthy donors (n=6).Mature spermatozoa were isolated and incubated with 5 mmol/L β-nicotinamide adenine dinucleotide phosphate (NADPH) for up to 24 h to induce ROS.Sperm morphology was evaluated using strict Tygerberg's criteria and the SDI.ROS levels and DNA damage were assessed using chemiluminescence and terminal deoxynucleotidyl transferase-mediated fluorescein- dUTP nick end labeling (TUNEL) assays,respectively.Results:SDI values (median [interquartiles]) were higher in patients than donors (2 [1.8,2.1] vs.1.53 [1.52,1.58],P=0.008).Aliquots treated with NADPH showed higher ROS levels (1.22 [0.30,1.87] vs.0.39 [0.10,0.57],P=0.03) and higher incidence of DNA damage than those not treated (10 [4.69,24.85] vs.3.85 [2.58,5.10],P=0.008).Higher DNA damage was also seen following 24 h of incubation in patients compared to donors.SDI correlated with the percentage increase in sperm DNA damage following incubation for 24 h in samples treated with NADPH (r=0.7,P=0.008) and controls (r=0.58,P=0.04). Conclusion:SDI may be a useful tool in identifying potential infertile males with abnormal prevalence of oxidative stress (OS)-induced DNA damage.NADPH plays a role in ROS-mediated sperm DNA damage,which appears to be more evident in infertile patients with semen samples containing a high incidence of morphologically abnormal spermatozoa.展开更多
Scutellarin, a bioactive flavone isolated from Scutellaria baicalensis, has anti-inflammatory, anti-neurotoxic, anti-apoptotic and anti-oxida- tive effects and has been used to treat cardiovascular and cerebrovascular...Scutellarin, a bioactive flavone isolated from Scutellaria baicalensis, has anti-inflammatory, anti-neurotoxic, anti-apoptotic and anti-oxida- tive effects and has been used to treat cardiovascular and cerebrovascular diseases in China. However, the mechanisms by which scutellarin mediates neuroprotection in cerebral ischemia remain unclear. The interaction between scutellarin and nicotinamide adenine dinucleotide phosphate oxidase 2 （NOX2） was assessed by molecular docking study, which showed that scutellarin selectively binds to NOX2 with high affinity. Cultures of primary astrocytes isolated from the cerebral cortex of neonatal Sprague-Dawley rats were pretreated with 2, 10 or 50 μM scutellarin for 30 minutes. The astrocytes were then subjected to oxygen/glucose deprivation by incubation for 2 hours in glucose-free Dulbecco＇s modified Eagle＇s medium in a 95% N2/5% CO2 incubator, followed by simulated reperfusion for 22 hours. Cell viability was assessed by cell counting kit-8 assay. Expression levels of NOX2, connexin 43 and caspase-3 were assessed by western blot assay. Reactive oxygen species were measured spectrophotometrically. Pretreatment with 10 or 50 μM scutellarin substantially increased viability, reduced the expression of NOX2 and caspase-3, increased the expression of connexin 43, and diminished the levels of reactive oxygen, species in astrocytes subjected to ischemia-＇reperfusion. We also assessed the effects of scutellarin in vivo in the rat transient middle cerebral artery occlusion model of cerebral ischemia-reperfusion injury. Rats were given intraperitoneal injection of 100 mg/kg scutellarin 2 hours before surgery. The Bederson scale was used to assess neurological deficit, and 2,3,5-triphenyltetrazolium chloride staining was used to measure infarct size. Western blot assay was used to assess expression of NOX2 and connexin 43 in brain tissue. Enzyme-linked immunosorbent assay was used to detect 8-hydroxydeoxyguanosine （8-OHdG）, 4-hydroxy-2-nonenal （4-HNE） and 3-nitrotyrosin （3-NT） in brain tissue. Immunofluorescence double staining was used to determine the co-expression of caspase-3 and NeuN. Pretreatment with scutellarin im- proved the neurological function of rats with focal cerebral ischemia, reduced infarct size, diminished the expression of NOX2, reduced levels of 8-OHdG, 4-HNE and 3-NT, and reduced the number of cells co-expressing caspase-3 and NeuN in the injured brain tissue. Furthermore, we examined the effect of the NOX2 inhibitor apocynin. Apocynin substantially increased connexin 43 expression in vivo and in vitro. Collectively, our findings suggest that scutellarin protects against ischemic injury in vitro and in vivo by downregulating NOX2, upregulating connexin 43, decreasing oxidative damage, and reducing apoptotic cell death.展开更多
基金National Natural Science Foundation of China (Grant No. 20832008 and 21002004)
文摘Three dinucleotides containing L-isonucleosides at 5＇-end were synthesized by an elegant phosphoramidite one-pot method. Their binding modes with HIV integrase were simulated and their anti-HIV activities in pseudotyped virus system were examined.
基金the National Natural Science Foundation of China(No.81770754)the Beiing Natural Science Foundation(No.7172081)at Beijing Chaoyang Hospital,Capital Medical University,through funding provided to YNN.
文摘The inhibition of 5-a reductase type 2(SRD5A2)by finasteride is commonly used for the management of urinary obstruction resulting from benign prostatic enlargement(BPE).Certain BPE patients showing no SRD5A2 protein expression are resistant to finasteride therapy.Our previous work showed that methylated cytosine-phosphate-guanine(CpG)islands in the SRD5A2 gene might account for the absence or reduction of SRD5A2 protein expression.Here,we found that the expression of the SRD5A2 protein was variable and that weak expression of the SRD5A2 protein(scored 0-100)occurred in 10.0%(4/40)of benign adult prostates.We showed that the expression of SRD5A2 was negatively correlated with DNA methyltransferase 1(DNMT1)expression.In vitro SRD5A2-negative BPH-1 cells were resistant to finasteride treatment,and SRD5A2 was re-expressed in BPH-1 cells when SRD5A2 was demethylated by 5-Aza-2T-deoxycytidine(5-Aza-CdR)or N-phthalyl-L-tryptophan(RG108).Furthermore,we determined the exact methylation ratios of CpG dinucleotides in a CpG island of SRD5A2 through MassArray quantitative methylation analysis.Ten methylated CpG dinucleotides,including four CpG dinucleotides in the promoter and six CpG dinucleotides in the first exon,were found in a CpG island located from-400 bp to+600 bp in SRD5A2,which might lead to the silencing of SRD5A2 and the absence or reduction of SRD5A2 protein expression.Finasteride cannot exert a therapeutic effect on patients lacking SRD5A2,which may partially account for the resistance to finasteride observed in certain BPE patients.
基金supported by National Key Research and Development Program of China(Grant Number:2023YFD1700502)Frontiers Science Center for New Organic Matter,Nankai University,(Grant Number:63181206)the Haihe Laboratory of Sustainable Chemical Transformations,China(Grant Number:YYJC202102).
文摘Cyclic dinucleotides(CDNs)play important physiological roles in bacteria,mammals and insects as a novel class of signaling molecules.However,the application of CDNs in agricultural pest control has not been reported yet.To explore the potential bioactivity of CDNs on agricultural pests,we synthesized ten kinds of CDNs containing adenine and guanine bases with different internucleotide linkages(30,30;20,30;20,20).The target CDNs were used to determine the antifeedant and insecticidal activity against common Lepidoptera pests including S.frugiperda,M.separata,and H.armigera.The bioassay tests indicated that 30,30-c-di-AMP showed the highest antifeedant activity(EC50?0.59 mg/L)against M.separata larvae among all the tested CDNs.Regarding insecticidal activity,20,30-c-di-AMP showed higher insecticidal activity against M.separata larvae with LC50 of 55.4 mg/L.RNA-seq further revealed that 30,30-c-di-AMP and 20,30-c-di-AMP exhibited a significant effect on the growth and development process of insects.More importantly,the bioactivity of 30,30-c-di-AMP was also closely correlated with the stimulation of insect immune inflammation.These results indicated that cyclic dinucleotides can affect the normal physiological process of insects,providing a new direction for managing pests.
基金the National Key Research and Development Program of China(2017YFD0200500)the National Natural Science Foundation of China(21740002,21837001)。
文摘Cyclic dinucleotides(CDNs) are known to activate stimulator of interferon genes(STING) and induce type I interferon responses, therefor possess great potentials to be of immunotherapeutic value for cancers and infectious diseases. However, the existence of different single nucleotide polymorphism(SNP) of human STING(hSTING) gene poses an obstacle to achieve broad-spectrum activation by CDNs. We reported here the design and synthesis of a total of 36 CDNs, representing all structural variations, that contain four bases(A, G, C, U) and two linkage directions(2′-5′-linked and 3′-5′-linked phosphodiester).Through systematic evaluation of IFN-β induction with a dual-luciferase reporter assay, we discovered that wild type hSTING and two isoforms(HAQ and AQ) showed strong response while hSTING-R232 H and R293 Q exhibited the relatively weak response to CDNs stimulation. For the first time, we found that the c[G(2′,5′)U(2′,5′)] showed excellent activity against all five hSTING variants even equivalent to the endogenous ligand c[G(2′,5′)A(3′,5′)]. Furthermore, we have also demonstrated that 3′-3′CDNs with two 3′-5′ phosphodiesters showed higher serum and hydrolase stability than 2′-2′ CDNs with two 2′-5′ phosphodiesters and 2′-3′ CDNs with one 2′-5′ and one 3′-5′ phosphodiester. It is very interesting to note that 2′-2′ CDNs has been found for the first time to show strong activity. These findings will stimulate our exploration for the new functional role of CDNs, and provide guidelines to design CDNs based hSTING targeted drugs.
基金Project supported by the National Natural Science Foundation of China
文摘RNase A catalyzes the hydrolysis of ribonucleic acids to form oligonucleotide fragments containing pyrimidineribonucleoside 2’, 3’-cyclic phosphate at the 3’-termini, which are then further hydrolyzed to produce oligonucleotide fragments with 3’ -phosphate group as the final products. This enzyme can also catalyze the formation of internucleotide linkage from pyrimidineribonucleoside 2’, 3’-cyclic phosphate and a nucleoside component with
基金A fellowship support from the Golda Meir Fellowship Fund,The Hebrew University of Jerusalem,Israel。
文摘Mitochondria are central organelles in cellular metabolism,orchestrating energy production,biosynthetic pathways,and signaling networks.Nicotinamide adenine dinucleotide(NAD+)and its reduced form(NADH)are essential for mitochondrial metabolism,functioning both as redox coenzymes and as signaling agents that help regulate cellular balance.Thus,while its major role is in energy production,NAD+is widely recognized as a metabolic cofactor and also serves as a substrate for various enzymes involved in cellular signaling,like sirtuins(SIRTs),poly(ADP-ribosyl)polymerases(PARPs),mono(ADP-ribosyl)transferases,and CD38.Sirtuins,a family of NAD+-dependent deacetylases,are critical in this regulatory network.SIRT3 removes acetyl groups from and enhances the activity of key enzymes that participate in fatty acid breakdown,the tricarboxylic acid(TCA)cycle,and the electron transport chain(etc),thereby enhancing mitochondrial efficiency and energy production.Mitochondrial NAD+biosynthesis involves multiple pathways,including the de novo synthesis from tryptophan via the kynurenine and the salvage pathway,which recycles nicotinamide back to NAD+.Moreover,NAD+concentrations influence mitochondrial dynamics such as fusion,fission,and mitophagy,which are essential for preserving mitochondrial integrity and function.NAD+alsomodulates the balance between glycolysis and oxidative phosphorylation,influencing the metabolic flexibility of cells.During NAD+depletion,mainly in metabolic disorders,cells often shift towards anaerobic glycolysis,reducing ATP production efficiency and increasing lactate production.This metabolic shift is associated with various pathophysiological conditions,including insulin resistance,neurodegeneration,and muscle wasting.This reviewexplores themultifaceted functions of NAD+in regulating mitochondrialmetabolism.It highlights the underlying causes and pathological outcomes of disrupted NAD+metabolism while exploring potential therapeutic targets and treatment strategies.
基金Shanghai Natural Science Foundation,No.21ZR1452300the Clinical Research Innovation Plan of Shanghai General Hospital,No.CCTR-2022B04.
文摘BACKGROUND Sepsis is a severe illness characterized by systemic and multiorgan reactive responses and damage.However,the impact of sepsis on the bone marrow,particularly on bone marrow mesenchymal stem cells(BMSCs),is less reported.BMSCs are critical stromal cells in the bone marrow microenvironment that maintain bone stability and hematopoietic homeostasis;however,the impairment caused by sepsis remains unknown.AIM To investigate the effects of sepsis on BMSCs and the underlying mechanisms.METHODS BMSCs were obtained from healthy donors and patients with sepsis.We compared the self-renewal capacity,differentiation potential,and hematopoietic supportive ability in vitro.Senescence of septic BMSCs was assessed usingβ-galactosidase staining,senescence-associated secretory phenotype,intracellular reactive oxygen species levels,and the expression of P16 and P21.Finally,the changes in septic BMSCs after nicotinamide adenine dinucleotide(NAD)treatment were evaluated.RESULTS Septic BMSCs showed decreased proliferation and self-renewal,bias towards adipogenic differentiation,and weakened osteogenic differentiation.Additionally,hematopoietic supportive capacity declines in sepsis.The levels of aging markers were significantly higher in the septic BMSCs.After NAD treatment,the proliferation capacity of septic BMSCs showed a recovery trend,with increased osteogenic and hematopoietic supportive capacities.Sepsis resulted in decreased expression of sirtuin 3(SIRT3)in BMSCs,whereas NAD treatment restored SIRT3 expression,enhanced superoxide dismutase enzyme activity,reduced intracellular reactive oxygen species levels,maintained mitochondrial stability and function,and ultimately rejuvenated septic BMSCs.CONCLUSION Sepsis accelerates the aging of BMSCs,as evidenced by a decline in self-renewal and osteogenic capabilities,as well as weakened hematopoietic support functions.These deficiencies can be effectively reversed via the NAD/SIRT3/superoxide dismutase pathway.
基金Supported by the Guangdong Basic and Applied Basic Research Fund Project,No.2022A1515110825 and No.2023A1515011092the Incubation Program for the Science and Technology Development of Chinese Medicine Guangdong Laboratory,No.HQL2024PZ033+5 种基金the Chi Xiaoling National Famous Traditional Chinese Medicine Expert Inheritance Studio,Teaching Letter from the State Traditional Chinese Medicine Office[2022],No.75the Advantage Disease Project of Guangdong Provincial Hospital of Traditional Chinese Medicine[2020],No.37the Science and Technology Planning Project of Guangdong Province,No.2023B1212060063the Project of Guangdong Provincial Key Laboratory of Chinese Medicine for Prevention and Treatment of Refractory Chronic Diseases,No.YN2023MB04the Clinical Research Projects of Guangdong Provincial Hospital of Chinese Medicine,No.YN2022QN05the Guangzhou Basic Research Program for Young Doctors in Basic and Applied Basic Research,No.2024A04J3004.
文摘BACKGROUND Inhibition of liver fibrosis plays a crucial role in curbing the advancement of chronic disease to cirrhosis and even liver cancer.However,modern medicine currently lacks direct anti-fibrotic drugs.He-He-Shu-Yang formula(HHSY)is a renowned Chinese medicine for the treatment of liver fibrosis.However,its mechanism of action has not been fully unraveled.AIM To explore the efficacy and mechanism of action of HHSY through in vitro and in vivo experiments.METHODS A liver fibrosis rat model(carbon tetrachloride-induced)was treated with low-or high-dose HHSY(10.42 g/kg or 20.84 g/kg)or with colchicine(1 mg/kg)for 9 weeks.In vitro,LX-2 human hepatic stellate cells(HSCs)were activated using transforming growth factor-β1 and subsequently treated with HHSY-containing serum or a nicotinamide adenine dinucleotide phosphate oxidase 4(NOX4)inhibitor.Through high-performance liquid chromatography,histopathology(hematoxylin and eosin,Masson),immunohistochemistry,western blot,and quantitative reverse transcription polymerase chain reaction analyses,we demonstrated that HHSY inhibited HSC activation and suppressed the NOX4/reactive oxygen species(ROS)/nucleotide binding oligomerization domain-like receptor family pyrin domain-containing 3(NLRP3)pathway.RESULTS In vivo,HHSY improved liver function and alleviated liver pathology,including reducing inflammatory cell infiltration,and liver fibrosis in carbon tetrachloride rats.with more significant effects at higher doses.Immunohistochemistry revealed that HHSY could decrease alpha-smooth muscle actin,NOX4,and NLRP3 expression,as well as serum ROS levels(O_(2)-and H_(2)O_(2),P<0.05).Western blot analysis confirmed HHSY also reduced NLRP3 protein levels(P<0.05).In vitro,HHSY at 1.25%or 2.5%reduced the levels of ACTA2 mRNA,NOX4 protein and NOX4 mRNA,ROS production,and NLRP3 and IL-1βmRNA in activated LX-2 cells(P<0.05).CONCLUSION HHSY effectively treats liver fibrosis,likely by inhibiting HSC activation through the NOX4/ROS/NLRP3 pathway.This underscores HHSY’s clinical relevance as a potential therapeutic option for liver fibrosis.
基金supported by the Natural Science Foundation of China(81873325)the State Administration of Traditional Chinese Medicine of Zhejiang Province(2021ZZ014).
文摘The study aimed to explore the efficacy and potential mechanisms of a naturally aromatic cyanogenic compound amygdalin(AMY)in treating glucocorticoid(GC)-associated necrosis of the femoral head(GANFH).We demonstrated that GC exacerbates the oxidative stress(OS)microenvironment via promoting nicotinamide adenine dinucleotide phosphate oxidase 4(NOX4)expression in human,rat,and mesenchymal stem cells(MSCs)samples,thus generating excessive reactive oxygen species(ROS),leading to increased apoptosis and unbalanced osteolipogenic differentiation.Furthermore,computational docking results revealed that AMY could bind specifically to the predicted binding sites of NOX4.Additionally,AMY ameliorated the OS microenvironment of MSCs via decreasing NOX4 expression and inhibiting NOX4/ROS/p38MAPK signaling,thereby reversing the GC-induced apoptosis and imbalanced osteolipogenic differentiation,and ultimately alleviating GANFH.In summary,we demonstrated for the first time that AMY attenuated apoptosis and maintained osteolipogenic differentiation balance in MSCs via specifically targeting NOX4,inhibiting NOX4/ROS/p38MAPK signaling,thereby treating GANFH.
文摘A full_length cDNA has been cloned encoding nicotinamide adenine dinucleotide phosphate_specific glutamate dehydrogenase (NADP_GDH) from Chlorella sorokiniana with the RT_PCR method. The complete nucleotide sequence of NADP_GDH gene had 94% homology to the previously reported one . The NADP_GDH gene was constructed into a vector highly expressed in plants. The specific activity of NADP_GDH in transformants was detected, but not in the control plants. All transformed shoots on MS medium containing lower concentration of nitrogen and the transformed seedlings grown in lower concentration of nitrogen vermiculite had higher growth rate and more leaves than the control plants. Transformed leaf discs cultured on MS medium containing different nitrogen concentrations had more chlorophyll contents compared to the controls. These results suggested that exogenous NADP_GDH may enhance the absorption and utilization to ammonium in plants. The increased weight of transformed leaf discs cultured on medium supplemented with different concentrations of phosphinothricin (PPT) was more than that of control discs. 0.5 μg/mL PPT could be used as a selecting drug instead of kanamycin to develop the transformants. These results suggested that the NADP_GDH gene might be used as a new selecting gene in the future research of plant gene engineering.
基金National Natural Science Foundation of China(Grant No.U1604285,21572013)
文摘C-di-GMP is one kind of second messengers which plays an important role not only in the regulation of various bacterial physiological activities but also in the activation of innate immune response to induce typeⅠinterferon in mammalian cells.In this assay,by using one-pot phosphoramidite method,three novel kinds of analogs of c-di-GMP including its phosphorthiates modified by ganciclovir(7 a,7 b,7 c)have been designed and synthesized.The immune-stimulatory results of these c-di-GMP analogs in RAW-Lucia ISG cells indicated that they couldn’t induce the release of typeⅠinterferon,which demonstrated that the intact structure of ribose moieties is very vital for their bioactivity upon the activation of STING signaling pathway.
基金the National Natural Science Foundation of China(Nos.20572061,20672104)the Chinese Ministry of Education and Zhengzhou University for financial support.
文摘The reactions of four different N-（O,O＇-diisopropyl） phosphoamino acids （DIPP-aa）, such as N-phosphoryl-L-α-alanine （DIPP- L-α-Ala）, N-phosphoryl-D-α-alanine （DIPP-D-α-A1a）, N-phosphoryl-β-alanine （DIPP-β-A1a） and N-phosphoryl-γ-amino butyric acid （DIPP-γ-Aba）, and four nucleosides, adenosine （A）, guanosine （G）, cytidine （C） and uridine （U）, were studied by electrospray ionization tandem mass spectrometry （ESI-MS/MS） and HPLC/ESI-MS. DIPP-L-α-A1a and DIPP-D-α-A1a produced the same phosphorylated nucleosides, dinucleotides and phosphoroligopeptide. However, DIPP-β-A1a and DIPP-γ-Aba gave no relevant products.
文摘Deformability of DNA is important for its superhelical folding in the nucleosome and has long been thought to be facilitated by periodic occurrences of certain dinucleotides along the sequences, with the period close to 10.5 bases. This study statistically examines the conformational properties of dinucleotides containing the 10.5 - base periodicity and those without that periodicity through scanning all nucleosome structures provided in PDB. By categorizing performances on the distribution of step parameter values, averaged net values, standard deviations and deformability based on step conformational energies, we give a detailed description as to the deformation preferences correlated with the periodicity for the 10 unique types of dinucleotides and summarize the possible roles of various steps in how they facilitate DNA bending. The results show that the structural properties of dinucleotide steps are influenced to various extents by the periodicity in nucleosomes and some periodic steps have shown a clear tendency to take specific bending or shearing patterns.
文摘Recent data implicate oxidative stress as a mediator of pulmonary hypertension (PH) and of the associated pathological changes to the pulmonary vasculature and right ventricle (RV). Increases in reactive oxygen species (ROS), altered redox state, and elevated oxidant stress have been demonstrated in the lungs and RV of several animal models of PH, including chronic hypoxia, monocrotaline toxicity, caveolin-1 knock-out mouse, and the transgenic Ren2 rat which overexpresses the mouse renin gene. Generation of ROS in these models is derived mostly from the activities of the nicotinamide adenine dinucleotide phosphate oxidases, xanthine oxidase, and uncoupled endothelial nitric oxide synthase. As disease progresses circulating monocytes and bone marrow-derived monocytic progenitor cells are attracted to and accumulate in the pulmonary vasculature. Once established, these inflammatory cells generate ROS and secrete mitogenic and fibrogenic cytokines that induce cell proliferation and fibrosis in the vascular wall resulting in progressive vascular remodeling. Deficiencies in antioxidant enzymes also contribute to pulmonary hypertensive states. Current therapies were developed to improve endothelial function, reduce pulmonary artery pressure, and slow the progression of vascular remodeling in the pulmonary vasculature by targeting deficiencies in either NO (PDE-type 5 inhibition) or PGI 2 (prostacyclin analogs), or excessive synthesis of ET-1 (ET receptor blockers) with the intent to improve patient clinical status and survival. New therapies may slow disease progression to some extent, but long term management has not been achieved and mortality is still high. Although little is known concerning the effects of current pulmonary arterial hypertension treatments on RV structure and function, interest in this area is increasing. Development of therapeutic strategies that simultaneously target pathology in the pulmonary vasculature and RV may be beneficial in reducing mortality associated with RV failure.
文摘A novel method for predicting hotspots and coldspots using support vector machine （SVM） based on statistical learning theory is developed. This method is applied to published 303 hot and 48 cold open reading frames （ORFs） in Saccharomyces cerevisiae. The sequence features of general dinucleotide abundance and dinucleotide abundance based on codon usage are extracted, and then the data sets are classified with different parameters and kernel functions combined with the method of two-fold cross validation. The result indicates that 87.47% accuracy can be reached when classifying hot and cold ORF sequences with the kernel of radial basis function combined with dinucleotide abundance based on codon usage.
基金partially supported by Merit Review Award(I01RX-001964-01)from the US Department of Veterans Affairs Rehabilitation Research and Development Service(to YD)the National Natural Science Foundation of China(81501141)+1 种基金Beijing New Star of Science and Technology Program of China(xx2016061)Beijing Tongzhou District Financial Fund,and Scientific Research Common Program of Beijing Municipal Commission of Education,China(KM201610025028)(to XG)
文摘Nicotinamide adenine dinucleotide phosphate oxidase(NOX) is a multisubunit enzyme complex that utilizes nicotinamide adenine dinucleotide phosphate to produce superoxide anions and other reactive oxygen species. Under normal circumstances, reactive oxygen species mediate a number of important cellular functions, including the facilitation of adaptive immunity. In pathogenic circumstances, however,excess reactive oxygen species generated by NOX promotes apoptotic cell death. In ischemic stroke, in particular, it has been shown that both NOX activation and derangements in glucose metabolism result in increased apoptosis. Moreover, recent studies have established that glucose, as a NOX substrate, plays a vital role in the pathogenesis of reperfusion injury. Thus, NOX inhibition has the potential to mitigate the deleterious impact of hyperglycemia on stroke. In this paper, we provide an overview of this research,coupled with a discussion of its implications for the development of NOX inhibition as a strategy for the treatment of ischemic stroke. Both inhibition using apocynin, as well as the prospect of developing more specific inhibitors based on what is now understood of the biology of NOX assembly and activation, will be highlighted in the course of our discussion.
文摘Aim:To investigate the impact of abnormal sperm morphology using the sperm deformity index (SDI) on reactive oxygen species (ROS) production and its correlation with sperm DNA damage.Methods:Semen samples were collected from men undergoing infertility screening (n=7) and healthy donors (n=6).Mature spermatozoa were isolated and incubated with 5 mmol/L β-nicotinamide adenine dinucleotide phosphate (NADPH) for up to 24 h to induce ROS.Sperm morphology was evaluated using strict Tygerberg's criteria and the SDI.ROS levels and DNA damage were assessed using chemiluminescence and terminal deoxynucleotidyl transferase-mediated fluorescein- dUTP nick end labeling (TUNEL) assays,respectively.Results:SDI values (median [interquartiles]) were higher in patients than donors (2 [1.8,2.1] vs.1.53 [1.52,1.58],P=0.008).Aliquots treated with NADPH showed higher ROS levels (1.22 [0.30,1.87] vs.0.39 [0.10,0.57],P=0.03) and higher incidence of DNA damage than those not treated (10 [4.69,24.85] vs.3.85 [2.58,5.10],P=0.008).Higher DNA damage was also seen following 24 h of incubation in patients compared to donors.SDI correlated with the percentage increase in sperm DNA damage following incubation for 24 h in samples treated with NADPH (r=0.7,P=0.008) and controls (r=0.58,P=0.04). Conclusion:SDI may be a useful tool in identifying potential infertile males with abnormal prevalence of oxidative stress (OS)-induced DNA damage.NADPH plays a role in ROS-mediated sperm DNA damage,which appears to be more evident in infertile patients with semen samples containing a high incidence of morphologically abnormal spermatozoa.
基金financially supported by the National Natural Science Foundation of China,No.81303115,81774042,81771353the Natural Science Foundation of Guangdong Province of China,No.S2013040016915+3 种基金the Science and Technology Program of Guangzhou City of China,No.201508020050,201604020003the Pearl River S&T Nova Program of Guangzhou,the Postdoctoral Foundation of China,No.BBK42913K09,201003345,BBH429151701a grant from the Hong Kong Scholar Program,Guangzhou University of TCM 2017 High Level University Construction Program,No.A1-AFD018171Z11096a grant from the Specialty Program of Guangdong Province Hospital of Traditional Chinese Medicine of China,No.YN2016MJ07,YN2015QN16,YN2015B2025
文摘Scutellarin, a bioactive flavone isolated from Scutellaria baicalensis, has anti-inflammatory, anti-neurotoxic, anti-apoptotic and anti-oxida- tive effects and has been used to treat cardiovascular and cerebrovascular diseases in China. However, the mechanisms by which scutellarin mediates neuroprotection in cerebral ischemia remain unclear. The interaction between scutellarin and nicotinamide adenine dinucleotide phosphate oxidase 2 （NOX2） was assessed by molecular docking study, which showed that scutellarin selectively binds to NOX2 with high affinity. Cultures of primary astrocytes isolated from the cerebral cortex of neonatal Sprague-Dawley rats were pretreated with 2, 10 or 50 μM scutellarin for 30 minutes. The astrocytes were then subjected to oxygen/glucose deprivation by incubation for 2 hours in glucose-free Dulbecco＇s modified Eagle＇s medium in a 95% N2/5% CO2 incubator, followed by simulated reperfusion for 22 hours. Cell viability was assessed by cell counting kit-8 assay. Expression levels of NOX2, connexin 43 and caspase-3 were assessed by western blot assay. Reactive oxygen species were measured spectrophotometrically. Pretreatment with 10 or 50 μM scutellarin substantially increased viability, reduced the expression of NOX2 and caspase-3, increased the expression of connexin 43, and diminished the levels of reactive oxygen, species in astrocytes subjected to ischemia-＇reperfusion. We also assessed the effects of scutellarin in vivo in the rat transient middle cerebral artery occlusion model of cerebral ischemia-reperfusion injury. Rats were given intraperitoneal injection of 100 mg/kg scutellarin 2 hours before surgery. The Bederson scale was used to assess neurological deficit, and 2,3,5-triphenyltetrazolium chloride staining was used to measure infarct size. Western blot assay was used to assess expression of NOX2 and connexin 43 in brain tissue. Enzyme-linked immunosorbent assay was used to detect 8-hydroxydeoxyguanosine （8-OHdG）, 4-hydroxy-2-nonenal （4-HNE） and 3-nitrotyrosin （3-NT） in brain tissue. Immunofluorescence double staining was used to determine the co-expression of caspase-3 and NeuN. Pretreatment with scutellarin im- proved the neurological function of rats with focal cerebral ischemia, reduced infarct size, diminished the expression of NOX2, reduced levels of 8-OHdG, 4-HNE and 3-NT, and reduced the number of cells co-expressing caspase-3 and NeuN in the injured brain tissue. Furthermore, we examined the effect of the NOX2 inhibitor apocynin. Apocynin substantially increased connexin 43 expression in vivo and in vitro. Collectively, our findings suggest that scutellarin protects against ischemic injury in vitro and in vivo by downregulating NOX2, upregulating connexin 43, decreasing oxidative damage, and reducing apoptotic cell death.
