Quercetin Alleviates Lipopolysaccharide-Induced Cardiac Inflammation via Inhibiting Autophagy and Programmed Cell Death

Objective The aim of this study is to explore the potential modulatory role of quercetin against Endotoxin or lipopolysaccharide(LPS)induced septic cardiac dysfunction.Methods Specific pathogen-free chicken embryos(n=120)were allocated untreated control,phosphate buffer solution(PBS)vehicle,PBS with ethanol vehicle,LPS(500 ng/egg),LPS with quercetin treatment(10,20,or 40 nmol/egg,respectively),Quercetin groups(10,20,or 40 nmol/egg).Fifteenday-old embryonated eggs were inoculated with abovementioned solutions via the allantoic cavity.At embryonic day 19,the hearts of the embryos were collected for histopathological examination,RNA extraction,real-time polymerase chain reaction,immunohistochemical investigations,and Western blotting.Results They demonstrated that the heart presented inflammatory responses after LPS induction.The LPS-induced higher mRNA expressions of inflammation-related factors(TLR4,TNFα,MYD88,NF-κB1,IFNγ,IL-1β,IL-8,IL-6,IL-10,p38,MMP3,and MMP9)were blocked by quercetin with three dosages.Quercetin significantly decreased immunopositivity to TLR4 and MMP9 in the treatment group when compared with the LPS group.Quercetin significantly decreased protein expressions of TLR4,IFNγ,MMP3,and MMP9 when compared with the LPS group.Quercetin treatment prevented LPS-induced increase in the mRNA expression of Claudin 1 and ZO-1,and significantly decreased protein expression of claudin 1 when compared with the LPS group.Quercetin significantly downregulated autophagyrelated gene expressions(PPARα,SGLT1,APOA4,AMPKα1,AMPKα2,ATG5,ATG7,Beclin-1,and LC3B)and programmed cell death(Fas,Bcl-2,CASP1,CASP12,CASP3,and RIPK1)after LPS induction.Quercetin significantly decreased immunopositivity to APOA4,AMPKα2,and LC3-II/LC3-I in the treatment group when compared with the LPS group.Quercetin significantly decreased protein expressions of AMPKα1,LC3-I,and LC3-II.Quercetin significantly decreased the protein expression to CASP1 and CASP3 by immunohistochemical investigation or Western blotting in treatment group when compared with LPS group.Conclusion Quercetin alleviates cardiac inflammation induced by LPS through modulating autophagy,programmed cell death,and myocardiocytes permeability.

Identification of key genes regulating the synthesis of quercetin derivatives in Rosa roxburghii through integrated transcriptomics and metabolomics

Rosa roxburghii fruit is rich in flavonoids, but little is known about their biosynthetic pathways. In this study, we employed transcriptomics and metabolomics to study changes related to the flavonoids at five different stages of R. roxburghii fruit development. Flavonoids and the genes related to their biosynthesis were found to undergo significant changes in abundance across different developmental stages, and numerous quercetin derivatives were identified. We found three gene expression modules that were significantly associated with the abundances of the different flavonoids in R. roxburghii and identified three structural UDP-glycosyltransferase genes directly involved in the synthesis of quercetin derivatives within these modules. In addition, we found that RrBEH4, RrLBD1 and RrPIF8could significantly increase the expression of downstream quercetin derivative biosynthesis genes. Taken together,these results provide new insights into the metabolism of flavonoids and the accumulation of quercetin derivatives in R. roxburghii.

Reduction of the oxidative damage to H_(2)O_(2)-induced HepG2 cells via the Nrf2 signalling pathway by plant flavonoids Quercetin and Hyperoside

Hyperoside and quercetin are similar in molecular structures.In this study,the antioxidant regulatory targets of hyperoside and quercetin are mainly in the nuclear factor(erythroid-2-derived)-related factor 2(Nrf2)pathway predicted by network pharmacology.And the antioxidant effect and mechanism of hyperoside and quercetin were measured and compared in H_(2)O_(2)-induced Hep G2 cells and Caenorhabditis elegans.The findings indicated that quercetin was more effective than hyperoside in reducing oxidative damage,which was proved by improved cell viability,decreased reactive oxygen species(ROS)production,decreased cellular apoptosis,and alleviated mitochondrial damage.In addition,quercetin was more efficient than hyperoside in enhancing the expression of Nrf2-associated m RNAs,increasing the activities of superoxide dismutase(SOD),glutathione peroxidase(GSH-Px),and catalase(CAT),and reducing the cellular malondialdehyde(MDA)content.Quercetin was superior to hyperoside in prolonging the lifespan of worms,decreasing the accumulation of lipofuscin,inhibiting ROS production,and increasing the proportion of skn-1 in the nucleus.With the Nrf2 inhibitor ML385,we verified that quercetin and hyperoside primarily protected the cells against oxidative damage via the Nrf2 signalling pathway.Furthermore,molecular docking and dynamics simulations demonstrated that the quercetin-Kelch-like ECH-associated protein 1(Keap1)complex was more stable than the hyperoside-Keap1 complex.The stable structure of the complex might hinder the binding of Nrf2 and Keap1 to release Nrf2 and facilitate its entry into the nucleus to play an antioxidant role.Overall,quercetin had a better antioxidant than hyperoside.

Protective mechanism of quercetin compounds against acrylamide-induced hepatotoxicity

Quercetin compounds have antioxidant,anti-inflammatory and anticancer pharmacological functions.Longterm exposure to acrylamide(AA)can cause liver injury and endanger human health.However,whether quercetin compounds can attenuate AA-induced liver injury and the specific mechanism are not clear.Here,we studied the mechanism and structure-activity relationship of quercetin compounds in reducing AA-induced hepatotoxicity in vivo and in vitro.In vivo studies found that quercetin-like compounds protect against AAinduced liver injury by reducing oxidative stress levels,activating the Akt/m TOR signaling pathway to attenuate autophagy,and improving mitochondrial apoptosis and endoplasmic reticulum stress-mediated apoptosis.In vitro studies found that quercetin compounds protected Hep G2 cells from AA by attenuating the activation of AA-induced autophagy,lowering reactive oxygen species(ROS)levels by exerting antioxidant effects and thus attenuating oxidative stress,increasing mitochondrial membrane potential(MMP),and improving apoptosis-related proteins,thus attenuating AA-induced apoptosis.Furthermore,the conformational differences between quercetin compounds correlated with their protective capacity against AA-induced hepatotoxicity,with quercetin showing the best protective capacity due to its strongest antioxidant activity.In conclusion,quercetin compounds can protect against AA-induced liver injury through multiple pathways of oxidative stress,autophagy and apoptosis,and their protective capacity correlates with antioxidant activity.

Protective mechanism of quercetin in alleviating sepsis-related acute respiratory distress syndrome based on network pharmacology and in vitro experiments

BACKGROUND:Sepsis-related acute respiratory distress syndrome(ARDS)has a high mortality rate,and no effective treatment is available currently.Quercetin is a natural plant product with many pharmacological activities,such as antioxidative,anti-apoptotic,and anti-inflammatory effects.This study aimed to elucidate the protective mechanism of quercetin against sepsis-related ARDS.METHODS:In this study,network pharmacology and in vitro experiments were used to investigate the underlying mechanisms of quercetin against sepsis-related ARDS.Core targets and signaling pathways of quercetin against sepsis-related ARDS were screened and were verified by in vitro experiments.RESULTS:A total of 4,230 targets of quercetin,360 disease targets of sepsis-related ARDS,and 211 intersection targets were obtained via database screening.Among the 211 intersection targets,interleukin-6(IL-6),tumor necrosis factor(TNF),albumin(ALB),AKT serine/threonine kinase 1(AKT1),and interleukin-1β(IL-1β)were identified as the core targets.A Gene Ontology(GO)enrichment analysis revealed 894 genes involved in the inflammatory response,apoptosis regulation,and response to hypoxia.Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis identified 106 pathways.After eliminating and generalizing,the hypoxia-inducible factor-1(HIF-1),TNF,nuclear factor-κB(NF-κB),and nucleotide-binding and oligomerization domain(NOD)-like receptor signaling pathways were identified.Molecular docking revealed that quercetin had good binding activity with the core targets.Moreover,quercetin blocked the HIF-1,TNF,NF-κB,and NODlike receptor signaling pathways in lipopolysaccharide(LPS)-induced murine alveolar macrophage(MH-S)cells.It also suppressed the inflammatory response,oxidative reactions,and cell apoptosis.CONCLUSION:Quercetin ameliorates sepsis-related ARDS by binding to its core targets and blocking the HIF-1,TNF,NF-κB,and NOD-like receptor signaling pathways to reduce inflammation,cell apoptosis,and oxidative stress.

Protective effects of quercetin against H2O2 induced KGN cells injury

Background:Oxidative stress is one of the key contributors to cellular senescence and ovarian aging.Quercetin has a variety of physiological activities such as antioxidant.Given that hydrogen peroxide can cause oxidative damage to cells,the present study is designed to verify the protective effect of quercetin on human ovarian granulosa tumor cell line under oxidative stress.Methods:Cell counting kit-8 and lactate dehydrogenase assays examined cell viability and toxicity.Flow cytometry detected reactive oxygen species accumulation.Glutathione level was measured to analyze the oxidation resistance.Cell apoptosis was evaluated by Hoechst 33258 staining,acridine orange/Ethidium Bromide staining and western blot.The mitochondrial structure was observed under a transmission electron microscope.Mitochondrial membrane integrity was detected by JC-1 staining and western blot.Results:Hydrogen peroxide could induce cell injury,promote reactive oxygen species accumulation,and lead to glutathione depletion.hydrogen peroxide also resulted in mitochondrial morphological damage and depolarization,which activate caspase3/9 subsequently.However,quercetin could mitigate these damages.Conclusions:Present study found that hydrogen peroxide induced oxidative stress and mitochondrial apoptosis of human ovarian granulosa tumor cell line cells,which could be attenuated by quercetin.

Quercetin regulates depression-like behavior in CUMS rat models via TLR4/NF-κB signaling

Background:Depression is becoming increasingly prevalent around the world,imposing a substantial burden on individuals,families,as well as society.Quercetin is known to be highly effective in treating depression.However,additional research is needed to dissect the mechanisms of its anti-depressive effects.Methods:For this study,Sprague-Dawley(SD)rats were randomized into the control,model,quercetin,or fluoxetine group.The latter three groups were exposed to chronic unpredictable mild stress(CUMS)for 42 d.The first two groups received saline solution daily via oral gavage.Meanwhile,the quercetin group was orally administered a quercetin suspension(52.08 mg/kg)every day,while the fluoxetine group was orally administered a fluoxetine solution(2.08 mg/kg).Here,fluoxetine served as the positive control drug to compare the therapeutic effects of quercetin.The experimental period was 6 weeks.Depressive behaviors in rats were assessed through various physiological and behavioral measures.Additionally,pathological changes in hippocampal tissues were examined using Nissl staining.Serum cytokines were detected using an enzymelinked immunosorbent assay(ELISA),and immunohistochemistry was employed to quantify the levels and integral optical density(IOD)values of ionized calcium binding adaptor molecule-1(Iba-1)expression in the brain.Real-time fluorescence quantitative PCR(RT-qPCR)was utilized to evaluate the mRNA levels of inflammatory indicators as well as toll-like receptor 4(TLR4),and nuclear factor-κappa B P65(NF-κB P65)in hippocampus.Western blot(WB)technique was employed to observe the protein levels of TLR4,NF-κB P65,and phospho-NF-κB P65(p-NF-κB P65).Results:After 42 d of exposure to CUMS,rats exhibited a slow increase in body weight,a reduction in food intake,an abnormal preference for sugar water,and aberrant open-field behaviors.Pathological analysis revealed the disintegration,rupture,interruption,and disorganization of hippocampal neuronal cells after CUMS exposure,along with a decrease in Nissl bodies in the CA1 region.This was accompanied by the elevated expression of interleukin-1β(IL-1β),tumor necrosis factor-α(TNF-α),and interleukin-6(IL-6)in the serum and the upregulation of IL-1β,IL-6,and TNF-αmRNA expression in the hippocampus.Increases in Iba-1-positive cells and the IOD values of Iba-1 were detected in hippocampal microglia.Furthermore,TLR4 and NF-κB P65 mRNA and protein levels were upregulated in hippocampal tissues.Quercetin,an antidepressant,could alleviate depression-like symptoms in rats and downregulate inflammatory factors associated with the TLR4/NF-κB signaling pathway in hippocampal microglia,and its therapeutic effect was comparable to fluoxetine.Conclusion:In rat models of CUMS,quercetin may act as an antidepressant by inhibiting inflammation in hippocampal microglia via TLR4/NF-κB signaling pathway.These results offer experimental and theoretical support for applying quercetin in the clinical management of depression.

Based on network pharmacology,molecular docking and experimental validation to reveal the potential molecular mechanism of quercetin for the treatment of diarrheal irritable bowel syndrome

Objective:To explore the potential mechanism of action of quercetin in the treatment of diarrhea irritable bowel syndrome(IBS-D).Methods:The potential targets of quercetin were obtained from the TCMSP,SwissTar-getPrediction,and BATMAN-TCM databases.The targets of IBS-D were obtained by searching the GeneCards database with"diarrhea irritable bowel syndrome"as the keyword,and the targets of quercetin and IBS-D were intersected.The PPI network was constructed by Cytoscape 3.7.1 software.The intersected targets were imported into the DAVID database for GO functional analysis and KEGG pathway enrichment analysis.The binding ability of quercetin to the core targets was observed using molecular docking.Based on this,we established an IBS-D rat model,administered quercetin for intervention,and experimentally validated the network pharmacology prediction results by HE staining and ELISA assay.Results:Network pharmacology analysis showed that TP53,TNF-α,AKT1,VEGF-A,IL-6 factors and MAPK,PI3K-Akt signaling pathway as the core targets and pathways of quercetin for the treatment of IBS-D.The results of animal experiments revealed that quercetin could inhibit the secretion of TP53,TNF-α,AKT1,VEGF-A,IL-1βand IL-6,reduce the inflammatory response and improve IBS-D.Conclusion:Quercetin could protect colon tissue by regulating the expression of TP53,TNF-α,AKT1,VEGF-A,IL-1βand IL-6,thereby treating IBS-D.

Effects of Quercetin Extracted from Flower Buds of Sophora japonica cv.jinhuai on Proliferation and Apoptosis of Human Breast Cancer MCF-7 Cells

[Objectives]To investigate the effects of quercetin extracted from flower buds of Sophora japonica cv.jinhuai on the proliferation,apoptosis and migration of human breast cancer MCF-7 cells.[Methods]MTT assay,inverted microscope observation,hoechst33342 staining,flow cytometry(FCM)and wound healing assay were adopted to investigate the proliferation,morphological changes,apoptosis level and cell migration ability of human breast cancer MCF-7 cells,respectively.[Results]The morphological changes of cells in the treatment groups included gradually decreased number,reduced volume,vague cell contour,loose intercellular connection,uneven cytoplasm distribution and increased cell debris.With the increase of drug concentration,quercetin significantly inhibited the proliferation of human breast cancer MCF-7 cells(P<0.05).The number of apoptotic bodies increased gradually.When the concentration reached 100μmol/L,a large number of nuclear fragments appeared,and the level of apoptosis was statistically different(P<0.05).The mobility and migration ability of cells showed a decreasing trend,and the differences were statistically significant(P<0.05).[Conclusions]This study can provide experimental basis for clinical application of quercetin against breast cancer.

Anti-leishmanial,immunomodulatory and anti-oxidative activity of quercetin against cutaneous leishmaniasis caused by Leishmania major

Objective:To evaluate the in vitro and in vivo efficacy of quercetin and its immunomodulatory and anti-oxidative activity against Leishmania major(L.major).Methods:L.major promastigotes and amastigotes were incubated with different concentrations of quercetin to estimate EC_(50).For in vivo study,the base of tails of mice was infected with L.major.After developing ulcers in the inoculation site,mice were treated with 50 mg/kg quercetin orally for 28 consecutive days.The wound-healing potential of quercetin was evaluated by histopathological analysis of tissue sections stained by hematoxylin and eosin as well as Masson's trichrome.In addition,the levels of tumor necrosis factor-α,interleukin-6,malondialdehyde,and adiponectin,the ferric reducing ability of plasma,as well as superoxide dismutase and glutathione peroxidase activities were measured.Results:The EC_(50)values of quercetin against L.major promastigotes and intracellular amastigotes were 0.27 and 0.85μM,respectively.Histopathological analysis showed that fewer inflammatory cells,more fibroblasts,and more collagen deposition were observed in tissue sections of quercetin-treated mice.In addition,treatment with quercetin markedly increased glutathione peroxidase activity,the ferric reducing ability of plasma and adiponectin levels while decreasing malondialdehyde,interleukin-6,and tumor necrosis factor-αlevels.Conclusions:Quercetin shows anti-leishmanial activity,immunomodulatory,anti-oxidative,and anti-inflammatory effects.Therefore,it may be further explored as an effective drug in treating leishmaniasis.

Protocatechuic acid and quercetin attenuate ETEC-caused IPEC-1 cell inflammation and injury associated with inhibition of necroptosis and pyroptosis signaling pathways

Background:Necroptosis and pyroptosis are newly identified forms of programmed cell death,which play a vital role in development of many gastrointestinal disorders.Although plant polyphenols have been reported to protect intestinal health,it is still unclear whether there is a beneficial role of plant polyphenols in modulating necroptosis and pyroptosis in intestinal porcine epithelial cell line(IPEC-1)infected with enterotoxigenic Escherichia coli(ETEC)K88.This research was conducted to explore whether plant polyphenols including protocatechuic acid(PCA)and quercetin(Que),attenuated inflammation and injury of IPEC-1 caused by ETEC K88 through regulating necroptosis and pyroptosis signaling pathways.Methods:IPEC-1 cells were treated with PCA(40μmol/L)or Que(10μmol/L)in the presence or absence of ETEC K88.Results:PCA and Que decreased ETEC K88 adhesion and endotoxin level(P<0.05)in cell supernatant.PCA and Que increased cell number(P<0.001)and decreased lactate dehydrogenases(LDH)activity(P<0.05)in cell supernatant after ETEC infection.PCA and Que improved transepithelial electrical resistance(TEER)(P<0.001)and reduced fluorescein isothiocyanate-labeled dextran(FD4)flux(P<0.001),and enhanced membrane protein abundance of occludin,claudin-1 and ZO-1(P<0.05),and rescued distribution of these tight junction proteins(P<0.05)after ETEC infection.PCA and Que also declined cell necrosis ratio(P<0.05).PCA and Que reduced mRNA abundance and concentration of tumor necrosis factor-α(TNF-α),interleukin(IL)-6 and IL-8(P<0.001),and down-regulated gene expression of toll-like receptors 4(TLR4)and its downstream signals(P<0.001)after ETEC infection.PCA and Que down-regulated protein abundance of total receptor interacting protein kinase 1(t-RIP1),phosphorylated-RIP1(p-RIP1),p-RIP1/t-RIP1,t-RIP3,p-RIP3,mixed lineage kinase domain-like protein(MLKL),p-MLKL,dynamin-related protein 1(DRP1),phosphoglycerate mutase 5(PGAM5)and high mobility group box 1(HMGB1)(P<0.05)after ETEC infection.Moreover,PCA and Que reduced protein abundance of nod-like receptor protein 3(NLRP3),nod-like receptors family CARD domain-containing protein 4(NLRC4),apoptosis-associated speck-like protein containing a CARD(ASC),gasdermin D(GSDMD)and caspase-1(P<0.05)after ETEC infection.Conclusions:In general,our data suggest that PCA and Que are capable of attenuating ETEC-caused intestinal inflammation and damage via inhibiting necroptosis and pyroptosis signaling pathways.

Quercetin-derivatives painting the yellow petals of American lotus(Nelumbo lutea)and enzymatic basis for their accumulation

American lotus(Nelumbo lutea)is one of the two species in Nelumbo and has only yellow flower.Identification of total flavonoids showed wild American lotus contained almost only flavonols with quercetin 3-O-glucuronide to be the dominant pigment.The variation tendency of the total flavonol content was coincident with yellow color variation of petals during flower development.To understand the mechanism of accumulation and constituent of pigments in petals,three pivotal genes,NlFLS1,NlFLS2 and NlFLS3,which were predicted to encode flavonol synthases were isolated and characterized by analyses of basic bioinformatics,temporal and spatial expression patterns and enzymatic activity.Their temporal expression levels showed the same variation tendency,which was also consistent with the development-dependent variation of total flavonol content.Spatial expression patterns indicated the three genes should function in petals.All the three proteins were demonstrated to be bifunctional dioxygenase,possessing both flavonol synthase activity and flavanone 3-hydroxylase activity.Besides,other flavonol biosynthesis related genes were also investigated on their expression levels to give more clues on the mechanism.Substrate preferences of the three FLSs,substrate competitions between the FLSs and other flavonol biosynthesis related enzymes,and the greatly differential expression levels between F3’H(flavonoid 3-hydroxylase)and F3’5’H(flavonoid 3,5-hydroxylase)contributed to the flavonol constituent in the petals of America lotus,namely abundant quercetin-derivatives while very few kaempferol-derivatives and myricetin-derivatives.

Quercetin modulates ovarian autophagy-related molecules and stereological parameters in a rat model of PCOS

Objective:To examine the effect of quercetin on stereological parameters and autophagy-related genes in ovaries of polycystic ovary syndrome(PCOS)rats.Methods:Fifty female Sprague-Dawley rats were randomly divided into five groups:the control group,the ethanol group,the quercetin group(15 mg/kg/day),the PCOS group,as well as the PCOS+quercetin group.After the induction of PCOS,quercetin was administered orally for 30 days.Histological,stereological and real-time PCR analyses were carried out to evaluate the effect of quercetin on PCOS rats.Results:Stereological analysis revealed that quercetin significantly increased the number of ovarian follicles and the volume of corpus luteum and induced a significant decrease in atretic follicles in comparison to the PCOS group.In addition,quercetin markedly increased mTOR gene expression while decreasing Beclin-1 and LC3 gene expression.Conclusions:Quercetin strongly modulates the expression of ovarian autophagy-related genes and stereological parameters in PCOS rats.Therefore,it can be considered as an ameliorative component for ovarian follicular impairments.

Pulmonary delivery of mucus-traversing PF127-modified silk fibroin nanoparticles loading with quercetin for lung cancer therapy

The mucosal barrier remains a major barrier in the pulmonary drug delivery system,as mucociliary clearance in the airway accelerates the removal of inhaled nanoparticles(NPs).Herein,we designed and developed the inhalable Pluronic F127-modified silk fibroin NPs loading with quercetin(marked as QR-SF(PF127)NPs),aiming to solve the airway mucus barrier and improve the cancer therapeutic effect of QR.The PF127 coating on the SF NPs could attenuate the interaction between NPs and mucin proteins,thus facilitating the diffusion of SF(PF127)NPs in the mucus layer.The QR-SF(PF127)NPs had particle sizes of approximately 200 nm with negatively charged surfaces and showed constant drug release properties.Fluorescence recovery after photobleaching(FRAP)assay and transepithelial transport test showed that QR-SF(PF127)NPs exhibited superior mucus-penetrating ability in artificial mucus and monolayer Calu-3 cell model.Notably,a large amount of QR-SF(PF127)NPs distributed uniformly in the mice airway section,indicating the good retention of NPs in the respiratory tract.Themicemelanoma lungmetastasismodel was established,and the therapeutic effect of QR-SF(PF127)NPs was significantly improved in vivo.PF127-modified SF NPs may be a promising strategy to attenuate the interaction with mucin proteins and enhancemucus penetration efficiency in the pulmonary drug delivery system.

Quercetin induced HepG2 cells apoptosis through ATM/JNK/STAT3 signaling pathways

Liver cancer is the seventh most common malignant tumor in the world and is the second highest cause of death due to cancer.Quercetin,a flavonoid with low toxicity,widely exists in various fruits and vegetables.It has the potential to be a therapeutic agent against various cancers.This study aimed to demonstrate the anti-tumor effect of quercetin on HepG2 cells.Quercetin suppressed the HepG2 cell proliferation in a dose-dependent manner in cell viability assay.Induction of cell apoptosis was confirmed by apoptotic cells population(sub-G1 peak)detected by flow cytometer.A decrease in mitochondrial membrane potential and caspase-3 activation were also demonstrated in this study.Furthermore,quercetin induced HepG2 cell apoptosis through ROS-mediated phosphorylated ataxia-telangiectasia mutated,c-Jun Nterminal kinases,signal transducer,and activator of transcription 3(STAT-3),and Bax signaling pathways.These results suggest that quercetin has the potential to become an effective drug against the tumor.

Quercetin ameliorates oxidative stress-induced senescence in rat nucleus pulposus-derived mesenchymal stem cells via the miR-34a-5p/SIRT1 axis

BACKGROUND Intervertebral disc degeneration(IDD)is a main contributor to low back pain.Oxidative stress,which is highly associated with the progression of IDD,increases senescence of nucleus pulposus-derived mesenchymal stem cells(NPMSCs)and weakens the differentiation ability of NPMSCs in degenerated intervertebral discs(IVDs).Quercetin(Que)has been demonstrated to reduce oxidative stress in diverse degenerative diseases.AIM To investigate the role of Que in oxidative stress-induced NPMSC damage and to elucidate the underlying mechanism.METHODS In vitro,NPMSCs were isolated from rat tails.Senescence-associatedβ-galactosidase(SA-β-Gal)staining,cell cycle,reactive oxygen species(ROS),realtime quantitative polymerase chain reaction(RT-qPCR),immunofluorescence,and western blot analyses were used to evaluated the protective effects of Que.Meanwhile the relationship between miR-34a-5p and Sirtuins 1(SIRT1)was evaluated by dual-luciferase reporter assay.To explore whether Que modulates tert-butyl hydroperoxide(TBHP)-induced senescence of NPMSCs via the miR-34a-5p/SIRT1 pathway,we used adenovirus vectors to overexpress and downregulate the expression of miR-34a-5p and used SIRT1 siRNA to knockdown SIRT1 expression.In vivo,a puncture-induced rat IDD model was constructed,and X rays and histological analysis were used to assess whether Que could alleviate IDD in vivo.RESULTS We found that TBHP can cause NPMSCs senescence changes,such as reduced cell proliferation ability,increased SA-β-Gal activity,cell cycle arrest,the accumulation of ROS,and increased expression of senescence-related proteins.While abovementioned senescence indicators were significantly alleviated by Que treatment.Que decreased the expression levels of senescence-related proteins(p16,p21,and p53)and senescence-associated secreted phenotype(SASP),including IL-1β,IL-6,and MMP-13,and it increased the expression of SIRT1.In addition,the protective effects of Que on cell senescence were partially reversed by miR-34a-5p overexpression and SIRT1 knockdown.In vivo,X-ray,and histological analyses indicated that Que alleviated IDD in a punctureinduced rat model.CONCLUSION In summary,the present study provides evidence that Que reduces oxidative stress-induced senescence of NPMSCs via the miR-34a/SIRT1 signaling pathway,suggesting that Que may be a potential agent for the treatment of IDD.

槲皮素通过下调缓激肽受体B1表达减轻糖尿病大鼠神经病理性疼痛

目的:研究槲皮素通过下调缓激肽受体B1(BDKRB1)表达减轻糖尿病大鼠神经病理性疼痛的机制。方法:60只大鼠腹腔注射60 mg/kg链脲佐菌素建立糖尿病神经病理性疼痛(DNP)大鼠模型,采用随机数表法平均分为5组:模型组、槲皮素(100 mg/kg)组、BDKRB1过表达质粒组、空载质粒组、槲皮素(100 mg/kg)+BDKRB1过表达质粒组,另选12只大鼠腹腔注射等剂量生理盐水作为对照组。各组大鼠以药物分组干预处理后,检测大鼠机械性刺激痛觉、热刺激痛觉与冷刺激痛觉,比较各组机械性缩足阈值、冷刺激抬足时间、热敏潜伏期;免疫组织化学染色检测大鼠脊髓背根神经节淋巴细胞浸润情况,比较各组淋巴细胞功能相关抗原-1(LFA-1)阳性细胞比例;试剂盒测量大鼠血清炎症介质IL-17、环氧化酶-2(COX-2)、IL-18水平;RT-qPCR、Western blot分别检测大鼠脊髓背根神经节BDKRB1 mRNA及蛋白表达水平。结果:与对照组比较,模型组大鼠机械性缩足阈值、热敏潜伏期显著降低(P<0.05),冷刺激抬足时间、LFA-1阳性细胞比例、血清IL-17、COX-2及IL-18水平、BDKRB1mRNA及蛋白表达水平显著升高(P<0.05);与模型组、槲皮素+BDKRB1过表达质粒组分别比较,槲皮素组大鼠机械性缩足阈值、热敏潜伏期均升高(P<0.05),冷刺激抬足时间、LFA-1阳性细胞比例、血清IL-17、COX-2及IL-18水平、BDKRB1 mRNA及蛋白表达水平均降低(P<0.05);BDKRB1过表达质粒组大鼠机械性缩足阈值、热敏潜伏期均降低(P<0.05),冷刺激抬足时间、LFA-1阳性细胞比例、血清IL-17、COX-2及IL-18水平、BDKRB1 mRNA及蛋白表达水平均升高(P<0.05);空载质粒组大鼠各指标均无显著变化(P>0.05)。结论:槲皮素通过下调BDKRB1表达抑制炎症,减少淋巴细胞浸润,减轻糖尿病大鼠神经病理性疼痛症状。

槲皮素通过雌激素受体下调长非编码RNA MALAT-1并发挥抗乳腺癌的作用机制

目的探索槲皮素抑制乳腺癌细胞恶性生物学行为的分子机制。方法以乳腺癌细胞系MCF-7和MB231作为研究对象,用慢病毒LV-ERα、LV-MALAT-1转染乳腺癌MB231细胞和MCF7细胞,RT-qPCR检测MALAT-1表达,Western blot检测肿瘤细胞中ERα蛋白表达,CCK-8细胞实验、平板克隆形成实验检测细胞增殖能力,PI染色法检测细胞周期,通过mRFP-GFP-LC3荧光双标腺病毒转染检测自噬水平,观察槲皮素和雌二醇对乳腺癌细胞增殖能力的影响。结果17β-雌二醇(E2)可以促进乳腺癌细胞MCF-7的增殖,而5μmol·L^(-1)槲皮素可以明显逆转E2对增殖的促进作用(P<0.05)。槲皮素对不表达雌激素受体α(estrogen receptor-α,ERα)的乳腺癌细胞MB231不表现抑制作用;而过表达ERα后,槲皮素则抑制了E2对MB231-ERα的促进作用。同时槲皮素可以抑制E2激活的MALAT-1表达;并且其抑制作用被过表达MALAT-1所逆转,包括细胞增殖,细胞周期进展以及克隆形成能力。结论槲皮素依赖于ERα的表达对乳腺癌的增殖等恶性行为起抑制作用,并且很可能是通过抑制MALAT-1的表达来发挥作用。

槲皮素通过抑制MIP-1α/CCR1/CCR5信号通路减轻大鼠带状疱疹后神经痛的机制

目的 探讨槲皮素(Que)对大鼠带状疱疹后神经痛(PHN)及趋化因子配体3(CCL3,即MIP-1α)/C-C趋化因子受体(CCR)1/CCR5信号通路的影响。方法 将60只大鼠分为对照组(Con组)、PHN组、L-Que组(30 mg/kg)、M-Que组(60 mg/kg)、H-Que组(120 mg/kg)以及H-Que+MIP-1α组(120 mg/kg Que+0.4μg/kg重组MIP-1α)。检测各组大鼠机械痛阈值(PWT)、热痛阈值(TWL);试剂盒检测外周组织液腺苷、腺嘌呤核糖核苷酸(AMP)、腺苷二磷酸(ADP)以及脊髓背角样本肿瘤坏死因子-α(TNF-α)和白细胞介素-1β(IL-1β)水平;通过HE染色观察脊髓背角病理切片;免疫荧光染色检测脊髓背角小胶质细胞活化情况;Western blot检测MIP-1α/CCR1/CCR5信号通路蛋白表达。结果 PHN组脊髓背角组织出现破裂现象,神经束排列混乱,炎性细胞浸润、水肿,神经元轻微萎缩现象。与Con组相比,PHN组PWT值、腺苷、AMP、ADP水平降低(P<0.05),TWL值、TNF-α、IL-1β水平、Iba1阳性小胶质细胞数量以及MIP-1α、CCR1、CCR5蛋白水平均升高(P<0.05);Que治疗后,大鼠神经束排列杂乱现象有所改善,炎性细胞浸润减少,神经元萎缩现象减轻;与PHN组相比,L-Que组、M-Que组、H-Que组的PWT值、腺苷、AMP、ADP水平升高(P<0.05),TWL值、TNF-α、IL-1β水平、Iba1阳性小胶质细胞数量以及MIP-1α、CCR1、CCR5蛋白水平均降低(P<0.05),且Que作用效果呈剂量依赖性;与H-Que组相比,H-Que+MIP-1α组的PWT值、腺苷、AMP、ADP水平降低(P<0.05),TWL值、TNF-α、IL-1β水平、Iba1阳性小胶质细胞数量以及MIP-1α、CCR1、CCR5蛋白水平均升高(P<0.05)。结论 Que可能通过抑制MIP-1α/CCR1/CCR5信号通路减轻大鼠炎症反应,进而减轻PHN。

槲皮素调控MAPK通路对绝经后骨质疏松大鼠骨形成的影响

目的探讨槲皮素调节MAPK信号通路对绝经后骨质疏松大鼠模型骨形成的影响。方法将SPF级SD雌性大鼠分为假手术组、模型组、槲皮素低、高剂量组及补佳乐组。通过ELISA法检测大鼠血清雌激素E2水平、骨代谢标志物CBF-α1、CTX-Ⅰ、PINP、OC水平、炎性指标IL-6、TNF-α、IL-1β水平;HE染色观察大鼠骨组织形态学变化;TRAP染色观察N.Oc/BS;显微CT扫描大鼠股骨形态,测定大鼠股骨BMD、Tb.N、Tb.Th、Tb.Sp;WB检测MAPK信号通路相关蛋白表达。结果与假手术组相比,模型组大鼠血清E2、CBF-α1、CTX-Ⅰ、PINP、OC水平降低,IL-6、TNF-α、IL-1β水平增加,N.Oc/BS增加,BMD、Tb.N、Tb.Th降低,Tb.Sp增大(P<0.05);与模型组相比,槲皮素低、高剂量组及补佳乐组大鼠血清E2、CBF-α1、CTX-Ⅰ、PINP、OC水平增加,IL-6、TNF-α、IL-1β水平降低,N.Oc/BS降低,BMD、Tb.N、Tb.Th增高,Tb.Sp减小(P<0.05)。假手术组骨组织形态结构正常;模型组骨皮质厚度变薄,骨小梁数量减少且断裂,排列稀疏;槲皮素低、高剂量组及补佳乐组出现新生骨小梁,数量增加,骨组织形态、结构相对完整、清晰。与假手术组相比,模型组MAPK信号通路相关蛋白水平增加(P<0.05);与模型组相比,槲皮素低、高剂量组及补佳乐组MAPK信号通路相关蛋白水平降低(P<0.05)。结论槲皮素能够调节绝经后骨质疏松大鼠雌激素水平,改善骨代谢异常,缓解骨微结构变化,对骨质疏松具有保护作用。可能是通过抑制MAPK信号通路相关蛋白表达、减少破骨细胞形成、减少骨吸收来实现的。