This review gives a brief insight into the role of mitochondrial dysfunction and oxidative stress in the converging pathogenic processes involved in Parkinson’s disease(PD).Mitochondria provide cellular energy in the...This review gives a brief insight into the role of mitochondrial dysfunction and oxidative stress in the converging pathogenic processes involved in Parkinson’s disease(PD).Mitochondria provide cellular energy in the form of ATP via oxidative phosphorylation,but as an integral part of this process,superoxides and other reactive oxygen species are also produced.Excessive free radical production contributes to oxidative stress.Cells have evolved to handle such stress via various endogenous anti-oxidant proteins.One such family of proteins is the mitochondrial uncoupling proteins(UCPs),which are anion carriers located in the mitochondrial inner membrane.There are five known homologues(UCP1 to 5),of which UCP4 and 5 are predominantly expressed in neural cells.In a series of previous publications,we have shown how these neuronal UCPs respond to 1-methyl-4-phenylpyridinium(MPP+;toxic metabolite of MPTP)and dopamine-induced toxicity to alleviate neuronal cell death by preserving ATP levels and mitochondrial membrane potential,and reducing oxidative stress.We also showed how their expression can be influenced by nuclear factor kappa-B(NF-B)signaling pathway specifically in UCP4.Furthermore,we previously reported an interesting link between PD and metabolic processes through the protective effects of leptin(hormone produced by adipocytes)acting via UCP2 against MPP+-induced toxicity.There is increasing evidence that these endogenous neuronal UCPs can play a vital role to protect neurons against various pathogenic stresses including those associated with PD.Their expression,which can be induced,may well be a potential therapeutic target for various drugs to alleviate the harmful effects of pathogenic processes in PD and hence modify the progression of this disease.展开更多
BACKGROUND Uncoupling protein 1(UCP1)plays a pivotal role in modulating energy expen-diture and maintaining metabolic homeostasis within brown and beige adipo-cytes.It has also been implicated in tumorigenesis.AIM To ...BACKGROUND Uncoupling protein 1(UCP1)plays a pivotal role in modulating energy expen-diture and maintaining metabolic homeostasis within brown and beige adipo-cytes.It has also been implicated in tumorigenesis.AIM To investigate the expression and function of UCP1 in gastric cancer(GC).METHODS UCP1 protein expression in 211 GC tissues was examined using immunohisto-chemistry.Bisulfite sequencing PCR(BSP)was used to detect the methylation status of the UCP1 promoter in GC cell lines and tissues.The relationship between UCP1 expression and clinicopathological parameters was analyzed.CCK8,scratch,transwell,and flow cytometry assays were carried out to analyze the proliferation,migration,invasion,and apoptosis of GC cell lines after knockdown or overexpression of UCP1 in vitro.A nude mouse tumor xenograft model was used to investigate the function of UCP1 in vivo.RNA sequencing,Kyoto Ency-clopedia of Genes and Genomes analysis,and Rap1 pull-down assays were performed to identify the pathway associated with UCP1.RESULTS Loss of UCP1 was significantly associated with gender,poor differentiation,and advanced TNM stage of GC.Hypermethylation of UCP1 was confirmed in GC cells and tumor tissues by BSP.Overexpression of UCP1 suppressed GC cell proliferation,migration,and invasion,and it promoted apoptosis in vitro.UCP1 overexpression also suppressed GC tumor growth in vivo.Moreover,overexpression of UCP1 in GC cells resulted in a significant decrease in active Rap1 protein levels,whereas downregulation of UCP1 markedly enhanced Rap1 activity.CONCLUSION UCP1 downregulation in GC through promoter hypermethylation is related to the progression of GC,indicating that UCP1 plays a role as a tumor suppressor in GC.It regulates Rap1 signaling and may be a potential therapeutic target in GC.展开更多
Reactive oxygen species（ROS） are free radicals thought to mediate the neurotoxic effects of several neurodegenerative disorders.In the central nervous system,ROS can also trigger a phenotypic switch in both astrocyt...Reactive oxygen species（ROS） are free radicals thought to mediate the neurotoxic effects of several neurodegenerative disorders.In the central nervous system,ROS can also trigger a phenotypic switch in both astrocytes and microglia that further aggravates neurodegeneration,termed reactive gliosis.Negative regulators of ROS,such as mitochondrial uncoupling protein 2（UCP2） are neuroprotective factors that decrease neuron loss in models of stroke,epilepsy,and parkinsonism.However,it is unclear whether UCP2 acts purely to prevent ROS production,or also to prevent gliosis.In this review article,we discuss published evidence supporting the hypothesis that UCP2 is a neuroprotective factor both through its direct effects in decreasing mitochondrial ROS and through its effects in astrocytes and microglia.A major effect of UCP2 activation in glia is a change in the spectrum of secreted cytokines towards a more anti-inflammatory spectrum.There are multiple mechanisms that can control the level or activity of UCP2,including a variety of metabolites and micro RNAs.Understanding these mechanisms will be key to exploitingthe protective effects of UCP2 in therapies for multiple neurodegenerative conditions.展开更多
AIM:To detect the expression of mitochondrial uncoupling protein 2(UCP2)in colon cancer and analyze the relation between UCP2 expression and clinical pathological features of colon cancer.METHODS:Fifteen colon tissue ...AIM:To detect the expression of mitochondrial uncoupling protein 2(UCP2)in colon cancer and analyze the relation between UCP2 expression and clinical pathological features of colon cancer.METHODS:Fifteen colon tissue samples and 15 its adjacent tissue samples were obtained from colon cancer patients during surgical interventions.UCP2 expression was detected with immunohistochemical method in 10 normal controls,10 hyperplastic polyp patients,20 tubular adenoma patients and 78 colon cancer patients.Patients with rectal cancer were excluded.Quantitative reverse transcription polymerase chain reaction and Western blotting were used to detect UCP2 expressions in colon cancer tissue samples and its adjacent tissue samples.Relation between UCP2 expression and clinical pathological features of colon cancer was also analyzed.RESULTS:The UCP2 mRNA expression level was fourfold higher in colon cancer tissue samples than in its adjacent tissue samples.The UCP2 protein expression level was three-fold higher in colon cancer tissue samples than in its adjacent normal tissue samples.The UCP2 was mainly expressed in cytoplasm.The UCP2 was not expressed in normal colon mucosa.Strong positive staining for UCP2 with a diffuse distribution pattern was identified throughout the mucosa in colon cancer tissue samples with a positive expression rate of 85.9%.The UCP2 expression level was higher in colon cancer tissue samples at clinical stagesⅢandⅣthan in those at stageⅠ+Ⅱ.Univariate analysis showed that the high UCP2 expression level was significantly correlated to colon cancer metastasis(hazard ratio=4.321,confidence interval=0.035-0.682,P=0.046).CONCLUSION:UCP2 is highly expressed in human colon cancer tissue and may be involved in colon cancer metastasis.展开更多
Objective:To explore the effects of acupuncture on the expression of uncoupling protein 1（UCP1）gene of brown adipose tissue （BAT）in obese rats.Methods:The expression of UCP1gene ofBAT was determined with RT-PCR te...Objective:To explore the effects of acupuncture on the expression of uncoupling protein 1（UCP1）gene of brown adipose tissue （BAT）in obese rats.Methods:The expression of UCP1gene ofBAT was determined with RT-PCR technique.The changes of body weight,Lee’s index,body fat,andthe expression of UCP1gene of BAT in obese rats were observed before and after acupuncture.Results:The body weight,Lee’s indeX,body fat in obese rats were all markedly higher than those in normal rats,but the expression of UCP1gene of BAT in obese rats was all lower than that in normal rats.There werenegative correlation between the Obesity index and the expression of UCP1gent in BAT.After acupunc-ture the marked effect of weight loss was achieved while the expression of UCP1gene of BAT Obviously in-creased in obese rats.Conclusion:The abnormal reduction for expression of UCP1gene of BAT might bean important cause for the obesity.To promote the expression of UCP1in obese organism might be an im-portant cellular and mole展开更多
AIM:To investigate whether uncoupling protein 2(UCP2) affects oleic acid-induced secretion of glucagonlike peptide-1(GLP-1) in L-cells.METHODS:mRNA and protein expression of UCP2 were analyzed in human NCI-H716 cells,...AIM:To investigate whether uncoupling protein 2(UCP2) affects oleic acid-induced secretion of glucagonlike peptide-1(GLP-1) in L-cells.METHODS:mRNA and protein expression of UCP2 were analyzed in human NCI-H716 cells,which serve as a model for enteroendocrine L-cells,by quantitative reverse transcription-polymerase chain reaction and Western blotting before and after treatment with oleic acid.Localization of UCP2 and GLP-1 in NCI-H716 cells was assessed by immunofluorescence labeling.NCI-H716 cells were transiently transfected with a small interfering RNA(siRNA) that targets UCP2(siUCP2) or with a nonspecific siRNA using Lipofectamine 2000.The concentrations of bioactive GLP-1 in the medium were measured by enzyme linked immunosorbent assay.RESULTS:Both GLP-1 and UCP2 granules were expressed mainly in the cytoplasm of NCI-H716 cells.NCI-H716 cells that secreted GLP-1 also expressed UCP2.Time-course experiments revealed that release of GLP-1 from NCI-H716 cells into the medium reached a maximum at 120 min and remained stable until at least 180 min after treatment with oleic acid(the level of GLP-1 increased about 2.3-fold as compared with the level of GLP-1 in the control cells,P < 0.05).In an experiment to determine dose dependence,stimulation of NCI-H716 cells with ≤ 8 mmol oleic acid led to a concentration-dependent release of GLP-1 into the medium;10 mmol oleic acid diminished the release of GLP-1.Furthermore,GLP-1 secretion induced by oleic acid from NCI-H716 cells that were transfected with siUCP2 decreased to 41.8%,as compared with NCI-H716 cells that were transfected with a non-specific siRNA(P < 0.01).CONCLUSION:UCP2 affected GLP-1 secretion induced by oleic acid.UCP2 plays an important role in L-cell secretion that is induced by free fatty acids.展开更多
The effect of target-directed regulation of the uncoupling protein-2 （UCP-2） gene expression on the ischemia-reperfusion injury of hepatocytes under different conditions was investigated. The expression plasmid and ...The effect of target-directed regulation of the uncoupling protein-2 （UCP-2） gene expression on the ischemia-reperfusion injury of hepatocytes under different conditions was investigated. The expression plasmid and RNAi plasmid targeting UCP-2 gene were constructed and trans- fected into normal hepatocytes and fatty liver cells, respectively. The expression of UCP-2 mRNA was detected by real time PCR. The cells were divided into normal cell group （NCG）, group of normal cells transfected with empty vector （EVNCG）, group of normal cells transfected with expression plasmid （EPNCG）, fatty liver cell group （FCG） and group of fatty liver cells transfected with RNAi plasmid （RPFCG）. The ischemia-reperfusion model in vitro was established. One, 6, 12 and 24 h after reperfusion, Annexin V/PI flow cytometry was used to measure cell necrosis rate, apoptosis rate and survival rate. Simultaneously, the intracellular ATP, ROS and MDA levels were determined. The re- sults showed that 1, 6, 12 and 24 h after ischemia-reperfusion, the intracellular ROS, MDA and ATP levels and cell survival rate in EPNCG were significantly lower, and cell necrosis rate significantly higher than in NCG and EVNCG, but there was no significant difference in apoptosis rate among NCG, EVNCG and EPNCG （P〉005）. Six, 12 and 24 h after reperfusion there was no significant dif- ference in ROS, MDA levels and apoptosis rate between FCG and RPFCG （P〉0.05）, but the ATP level and survival rate of cells in RPFCG were higher than in FCG （P〈0.05）. It was concluded that down-regulation of the UCP-2 gene expression in steatotic hepatocytes could alleviate the ische- mia-reperfusion injury of liver cells.展开更多
Background: Pancreatic ductal adenocarcinoma(PDAC) is a disease of the elderly mostly because its development from preneoplastic lesions depends on the accumulation of gene mutations and epigenetic alterations over ti...Background: Pancreatic ductal adenocarcinoma(PDAC) is a disease of the elderly mostly because its development from preneoplastic lesions depends on the accumulation of gene mutations and epigenetic alterations over time. How aging of non-cancerous tissues of the host affects tumor progression, however, remains largely unknown. Methods: We took advantage of a model of accelerated aging, uncoupling protein 2-deficient( Ucp2 knockout, Ucp2 KO) mice, to investigate the growth of orthotopically transplanted Ucp2 wild-type(WT) PDAC cells(cell lines Panc02 and 6606PDA) in vivo and to study strain-dependent differences of the PDAC microenvironment. Results: Measurements of tumor weights and quantification of proliferating cells indicated a significant growth advantage of Panc02 and 6606PDA cells in WT mice compared to Ucp2 KO mice. In tumors in the knockout strain, higher levels of interferon-γ m RNA despite similar numbers of tumor-infiltrating T cells were observed. 6606PDA cells triggered a stronger stromal reaction in Ucp2 KO mice than in WT animals. Accordingly, pancreatic stellate cells from Ucp2 KO mice proliferated at a higher rate than cells of the WT strain when they were incubated with conditioned media from PDAC cells. Conclusions: Ucp2 modulates PDAC microenvironment in a way that favors tumor progression and implicates an altered stromal response as one of the underlying mechanisms.展开更多
BACKGROUND： Uncoupling protein 2 （UCP2） has been suggested to inhibit mitochondrial production of reactive oxygen species （ROS） by decreasing the mitochondrial membrane potential. Experimental acute pancreatitis ...BACKGROUND： Uncoupling protein 2 （UCP2） has been suggested to inhibit mitochondrial production of reactive oxygen species （ROS） by decreasing the mitochondrial membrane potential. Experimental acute pancreatitis is associated with increased UCP2 expression, whereas UCP2 deficiency retards regeneration of aged mice from acute pancreatitis. Here, we have addressed biological and molecular functions of UCP2 in pancreatic stellate cells （PSCs）, which are involved in pancreatic wound repair and fibrogenesis. METHODS： PSCs were isolated from 12 months old （aged） UCP2^-/- mice and animals of the wild-type （WT） strain C57BL/6. Proliferation and cell death were assessed by em- ploying trypan blue staining and a 5-bromo-2＇-deoxyuridine incorporation assay. Intracellular fat droplets were visualized by oil red O staining. Levels of mRNA were determined by RT-PCR, while protein expression was analyzed by immunoblotting and immunofluorescence analysis. Intracellular ROS levels were measured with 2＇,7＇-dichlorofluorescin diacetate. Expression of senescence-associated β-galactosidase （SA β-Gal） was used as a surrogate marker of cellular senescence. RESULTS： PSCs derived from UCP2^-/- mice proliferated at a lower rate than cells from WT mice. In agreement with this observation, the UCP2 inhibitor genipin displayed dose- dependent inhibitory effects on WT PSC growth. Interestingly, ROS levels in PSCs did not differ between the two strains, and PSCs derived from UCP2^-/- mice did not senesce faster than those from corresponding WT cells. PSCs from UCP2^-/- mice and WT animals were also indistinguishable with respect to the activation-dependent loss of intracellular fat droplets, expression of the activation marker α-smooth muscle actin, type I collagen and the autocrine/paracrine mediators interleukin-6 and transforming growth factor-I~ 1. CONCLUSIONS： A reduced proliferative capacity of PSC from aged UCP2^-/- mice may contribute to the retarded regeneration after acute pancreatitis. Apart from their slower growth, PSC of UCP2^-/- mice displayed no functional abnormalities. The antifibrotic potential of UCP2 inhibitors deserves further attention.展开更多
Uncoupling protein 1 (UCP1) expressed by the brown adipose tissue (BAT) in the mitochondrial crista acts as a homeostatic thermogenerator of eutherians. The evaluation of UCP1 expression in the BAT offers significant ...Uncoupling protein 1 (UCP1) expressed by the brown adipose tissue (BAT) in the mitochondrial crista acts as a homeostatic thermogenerator of eutherians. The evaluation of UCP1 expression in the BAT offers significant scientific insight, especially in studies targeting limited areas such as the periarterial and pericardial regions of small experimental mammals. However, the negligible amount of this adipose tissue would render the general quantitative evaluation of the protein unreliable because of lipid contamination and low protein concentration. To address this problem, we quantitatively evaluated UCP1 expression in the mitochondrion of the mouse interscapular BAT using immunoelectron microscopy and immunohistochemical studies using a combination of primary and secondary antibodies in scheme A (rabbit anti-UCP1 IgG/gold particle-conjugated goat anti-rabbit IgG), B (rabbit IgG/gold particle-conjugated goat anti-rabbit IgG), C (rabbit anti-UCP1 IgG/gold particle-unconjugated goat anti-rabbit IgG), and D (rabbit IgG/gold particle-unconjugated goat anti-rabbit IgG). Scheme A shows the immunopositive reaction of obvious gold particles in the mitochondrial area, whereas other procedures revealed less distinctive reactions. The distinctive gold particle immunoreaction comprised electrical high-density spots with a mean diameter of >5 nm. However, in scheme B, the electrical high-density spots were scattered outside the mitochondrion and were significantly smaller than 4 nm;schemes C and D demonstrated few immunoreactions. Logistic regression analysis between schemes A and B showed that the threshold diameter of the electrical high-density spots measuring >5 nm indicated a true positive immunoreaction to anti-UCP1 antibody specifically in the mitochondrial area. Minor statistical difference was observed in the primary anti-UCP1 antibody between polyclonal IgG and monoclonal antibodies. Therefore, immunoelectron microscopy might be useful for evaluating negligible protein expression in some limited areas, such as UCP1 expression in the BAT of small experimental animals.展开更多
Cardiogenic shock is the leading cause of death among patients hospitalized with acute myocardial infarction （MI）. Understanding the mechanisms for acute pump failure is therefore important. The aim of this study is...Cardiogenic shock is the leading cause of death among patients hospitalized with acute myocardial infarction （MI）. Understanding the mechanisms for acute pump failure is therefore important. The aim of this study is to examine in an acute MI dog model whether mitochondrial bio-energetic function within non-ischemic wall regions are associated with pump failure. Anterior MI was produced in dogs via ligation of left anterior descending （LAD） coronary artery, that resulted in an infract size of about 30% of the left ventricular wall. Measurements ofhemodynamic status, mitochondrial function, free radical production and mitochondrial uncoupling protein 3 （UCP3） expression were determined over 24 h period. Hemodynamic measurements revealed a 〉 50% reduction in cardiac output at 24 h post infarction when compared to baseline. Biopsy samples were obtained from the posterior non-ischemic wall during acute infarction. ADP/O ratios for isolated mitochondria from non-ischemic myocardium at 6 h and 24 h were decreased when compared to the ADP/O ratios within the same samples with and without palmitic acid （PA）. GTP inhibition of （PA）-stimulated state 4 respiration in isolated mitochondria from the non-ischemic wall increased by 7% and 33% at 6 h and 24 h post-infarction respectively when compared to sham and pre-infarction samples. This would suggest that the mitochondria are uncoupled and this is supported by an associated increase in UCP3 expression observed on western blots from these same biopsy samples. Blood samples from the coronary sinus measured by electron paramagnetic resonance （EPR） methods showed an increase in reactive oxygen species （ROS） over baseline at 6 h and 24 h post-infarction. In conclusion, mitochondrial bio-energetic ADP/O ratios as a result of acute infarction are abnormal within the non-ischemic wall. Mitochondria appear to be energetically uncoupled and this is associated with declining pump function. Free radical production may be associated with the induction of uncoupling proteins in the mitochondria.展开更多
Extreme hot weather is occurring more frequently due to global warming,posing a significant threat to species survival.Birds in particular are more likely to overheat in hot weather because they have a higher body tem...Extreme hot weather is occurring more frequently due to global warming,posing a significant threat to species survival.Birds in particular are more likely to overheat in hot weather because they have a higher body temperature.This study used a heat stress model to investigate the antioxidant defense mechanisms and changes in fatty acid catabolism in Red-billed Leiothrix(Leiothrix lutea)to gain an understanding of how birds adapt to high temperatures.The birds were divided into five groups:a control group(30℃for 0 days),1 D group(40℃for 1 day),3 D group(40℃for 3 days),14 D group(40℃for 14 days)and recovery group(40℃for 14 days,then 30℃for 14 days).Our results indicated that when Red-billed Leiothrix are subjected to heat stress,malondialdehyde(MDA)content in the liver significantly increased,as did the enzyme activities of catalase(CAT),glutathione-SH-peroxidase(GSH-PX)and total antioxidant capacity(T-AOC)in the liver.Furthermore,there was a significant increase in heat shock protein 70(HSP70)expression in the liver,while avian uncoupling protein(avUCP)expression in muscle was significantly reduced.Additionally,there was a significant reduction in fatty acid catabolism enzyme activity such as 3-hydroxyacyl-CoAdehydrogenase(HOAD)activity in the heart,and carnitine palmitoyl transferase 1(CPT-1)and citrate synthase(CS)activity in the heart and liver.Furthermore,fatty acid translocase(FAT/CD36)in the heart,heart-type fatty acid binding protein(H-FABP)and fatty acid binding protein(FABP-pm)in the liver and heart were also significantly decreased.These changes reverted after treatment,but not to the same level as the control group.Our results indicated that when Red-billed Leiothrix are exposed to heat stress their internal antioxidant defense system is activated to counteract the damage caused by high temperatures.However,even with high antioxidant levels,prolonged high temperature exposure still caused some degree of oxidative damage possibly requiring a longer recovery time.Additionally,Red-billed Leiothrix may be able to resist heat stress by reducing fatty acid transport and catabolism.展开更多
AIM To investigate the role of the miR-133a-UCP2 pathway in the pathogenesis of inflammatory bowel disease (IBD) and to explore the potential downstream mechanisms with respect to inflammation, oxidative stress and en...AIM To investigate the role of the miR-133a-UCP2 pathway in the pathogenesis of inflammatory bowel disease (IBD) and to explore the potential downstream mechanisms with respect to inflammation, oxidative stress and energy metabolism. METHODS C57BL/6 mice were fed dextran sulfate sodium (DSS) liquid for 7 consecutive days, followed by the administration of saline to the DSS group, UCP2 siRNA to the UCP2 group and a miR-133a mimic to the miR-133a group on days 8 and 11. Body weight, stool consistency and rectal bleeding were recorded daily, and these composed the disease activity index (DAI) score for the assessment of disease severity. After cervical dislocation was performed on day 14, the length of the colon in each mouse was measured, and colonic tissue was collected for further study, which included the following: haematoxylin and eosin staining, UCP2 and miR-133a detection by immunohistochemical staining, western blot and quantitative real-time PCR, measurement of apoptosis by TUNEL assay, and the assessment of inflammation (TNF-alpha, IL-1 beta, IL-6 and MCP1), oxidative stress (H2O2 and MDA) and metabolic parameters (ATP) by ELISA and colorimetric methods. RESULTS An animal model of IBD was successfully established, as shown by an increased DAI score, shortened colon length and specific pathologic changes, along with significantly increased UCP2 and decreased miR-133a levels. Compared with the DSS group, the severity of IBD was alleviated in the UCP2 and the miR-133a groups after successful UCP2 knockdown and miR-133a overexpression. The extent of apoptosis, as well as the levels of TNF-alpha, IL-1 beta, MDA and ATP, were significantly increased in both the UCP2 and miR-133a groups compared with the DSS group. CONCLUSION The miR-133a-UCP2 pathway participates in IBD by altering downstream inflammation, oxidative stress and markers of energy metabolism, which provides novel clues and potential therapeutic targets for IBD.展开更多
Heat as a stressor of poultry has been studied extensively for many decades; it affects poultry production on a worldwide basis and has significant impact on well-being and production. More recently, the involvement o...Heat as a stressor of poultry has been studied extensively for many decades; it affects poultry production on a worldwide basis and has significant impact on well-being and production. More recently, the involvement of heat stress in inducing oxidative stress has received much interest. Oxidative stress is defined as the presence of reactive species in excess of the available antioxidant capacity of animal cells. Reactive species can modify several biologically cellular macromolecules and can interfere with cell signaling pathways. Furthermore, during the last decade, there has been an ever-increasing interest in the use of a wide array of natural feed-delivered phytochemicals that have potential antioxidant properties for poultry. In light of this, the current review aims to（1） summarize the mechanisms through which heat stress triggers excessive superoxide radical production in the mitochondrion and progresses into oxidative stress,（2） illustrate that this pathophysiology is dependent on the intensity and duration of heat stress,（3） present different nutritional strategies for mitigation of mitochondrial dysfunction, with particular focus on antioxidant phytochemicals.Oxidative stress that occurs with heat exposure can be manifest in all parts of the body; however, mitochondrial dysfunction underlies oxidative stress. In the initial phase of acute heat stress, mitochondrial substrate oxidation and electron transport chain activity are increased resulting in excessive superoxide production. During the later stage of acute heat stress, down-regulation of avian uncoupling protein worsens the oxidative stress situation causing mitochondrial dysfunction and tissue damage. Typically, antioxidant enzyme activities are upregulated. Chronic heat stress, however, leads to downsizing of mitochondrial metabolic oxidative capacity, up-regulation of avian uncoupling protein, a clear alteration in the pattern of antioxidant enzyme activities, and depletion of antioxidant reserves.Some phytochemicals, such as various types of flavonoids and related compounds, were shown to be beneficial in chronic heat-stressed poultry, but were less or not effective in non-heat-stressed counterparts. This supports the contention that antioxidant phytochemicals have potential under challenging conditions. Though substantial progress has been made in our understanding of the association between heat stress and oxidative stress, the means by which phytochemicals can alleviate oxidative stress have been sparsely explored.展开更多
Distribution and activity of mitochondda are key factors in neuronal development, synaptic plasticity and axogenesis. The majority of energy sources, necessary for cellular functions, originate from oxidative phosphor...Distribution and activity of mitochondda are key factors in neuronal development, synaptic plasticity and axogenesis. The majority of energy sources, necessary for cellular functions, originate from oxidative phosphorylation located in the inner mitochondrial membrane. The adenosine-5＇- triphosphate production is regulated by many control mechanism-firstly by oxygen, substrate level, adenosine-5＇-diphosphate level, mitochondrial membrane potential, and rate of coupling and proton leak. Recently, these mechanisms have been implemented by ＂second control mechanisms,＂ such as reversible phosphorylation of the tricarboxylic acid cycle enzymes and electron transport chain complexes, aUosteric inhibition of cytochrome c oxidase, thyroid hormones, effects of fatty acids and uncoupling proteins. Impaired function of mitochondria is implicated in many diseases ranging from mitochondrial myopathies to bipolar disorder and schizophrenia. Mitochondrial dysfunctions are usually related to the ability of mitochondria to generate adenosine-5＇-triphosphate in response to energy demands. Large amounts of reactive oxygen species are released by defective mitochondria similarly, decline of antioxidative enzyme activities （e.g. in the elderly） enhances reactive oxygen species production. We reviewed data concerning neuroplasticity, physiology, and control of mitochondrial oxidative phosphorylation and reactive oxygen species production.展开更多
Obesity-induced type 2 diabetes is mainly due to excessive free fatty acids leading to insulin resistance.Increasing thermogenesis is regarded as an effective strategy for hypolipidemia and hypoglycemia.Ginsenoside is...Obesity-induced type 2 diabetes is mainly due to excessive free fatty acids leading to insulin resistance.Increasing thermogenesis is regarded as an effective strategy for hypolipidemia and hypoglycemia.Ginsenoside is a natural active component in Panax ginseng C.A.Meyer,and some of them enhance thermogenesis.However,there are few studies on the mechanism and target of ginsenosides enhancing thermogenesis.Using thermogenic protein uncoupling protein 1(UCP1)-luciferase reporter assay,we identifi ed ginsenoside F1 as a novel UCP1 activator in the ginsenosides library.Using pull down assay and inhibitor interference,we found F1 binds toβ3-adrenergic receptors(β3-AR)to enhance UCP1 expression via cAMP/PKA/CREB pathway.We also investigated the ability of F1 on energy metabolism in obesity-induced diabetic mice,including body weight,body composition and energy expenditure.The results of proteomics showed that F1 signifi cantly up-regulated thermogenesis proteins and lipolytic proteins,but down-regulated fatty acid synthesis proteins.Ginsenoside F1 increased thermogenesis and ameliorated insulin resistance specifi cally by promoting the browning of white adipose tissue in obese mice.Additionally,ginsenoside F1 improves norepinephrine-induced insulin resistance in adipocytes and hepatocytes,and shows a stronger mitochondria respiration ability than norepinephrine.These fi ndings suggest that ginsenoside F1 is a promising lead compound in the improvement of insulin resistance.展开更多
Mitochondrial DNA(mtDNA) common deletion(CD) plays a significant role in aging and age-related diseases.In this study,we used D-galactose(D-gal) to generate an animal model of aging and the involvement and causative m...Mitochondrial DNA(mtDNA) common deletion(CD) plays a significant role in aging and age-related diseases.In this study,we used D-galactose(D-gal) to generate an animal model of aging and the involvement and causative mechanisms of mitochondrial damage in such a model were investigated.Twenty 5-week-old male Sprague-Dawley rats were randomly divided into two groups:D-gal group(n=10) and control group(n=10).The quantity of the mtDNA CD in the hippocampus was determined using a TaqMan real-time PCR assay.Transmission electron microscopy was used to observe the mitochondrial ultrastructure in the hippocampus.Western blot was used to detect the protein levels of NADPH oxidase(NOX) and uncoupling protein 2(UCP2).We found that the level of mtDNA CD was significantly higher in the hippocampus of D-gal-induced aging rats than in control rats.In comparison with the control group,the mitochondrial ultrastructure in the hippocampus of D-gal-treated rats was damaged,and the protein levels of NOX and UCP2 were significantly increased in the hippocampus of D-gal-induced aging rats.This study demonstrated that the levels of mtDNA CD and NOX protein expression were significantly increased in the hippocampus of D-gal-induced aging rats.These findings indicate that NOX-dependent reactive oxygen species generation may contribute to D-gal-induced mitochondrial damage.展开更多
The uncoupling protein(UCP)is a member of the mitochondrial membrane transporter family,which plays an important role in energy metabolism.In the present study,the UCP gene was considered as a candidate gene for chick...The uncoupling protein(UCP)is a member of the mitochondrial membrane transporter family,which plays an important role in energy metabolism.In the present study,the UCP gene was considered as a candidate gene for chicken growth traits,and the association of UCP gene SNPs with growth rate was investigated in the eighth generation of NEAUHLF broiler lines.Two SNPs were found in chicken UCP gene,and the association analysis results showed that both the individual and combination of chicken UCPgene SNPs were significantly associated with body weight of 7 weeks(BW7)and carcass weight(CW)(P〈0.05),and the combination had much significant effects than the single SNP.This research suggested that the UCP gene could be a candidate gene or linked to a major gene which affected growth traits in chicken.展开更多
Complex I （the NADH：ubiquinone oxidoreductase） of the mitochondrial respiratory chain is a complicated, multi-subunit, membrane- bound assembly and contains more than 40 different proteins in higher plants. In this...Complex I （the NADH：ubiquinone oxidoreductase） of the mitochondrial respiratory chain is a complicated, multi-subunit, membrane- bound assembly and contains more than 40 different proteins in higher plants. In this paper, we characterize the Arabidopsis homologue （designated as AtCIB22） of the B22 subunit of eukaryotic mitochondriai Complex I. AtCIB22 is a single-copy gene and is highly con- served throughout eukaryotes. AtCIB22 protein is located in mitochondria and the AtC1B22 gene is widely expressed in different tissues. Mutant Arabidopsis plants with a disrupted AtC1B22 gene display pleiotropic phenotypes including shorter roots, smaller plants and de- layed flowering. Stress analysis indicates that the AtC1B22 mutants＇ seed germination and early seedling growth are severely inhibited by sucrose deprivation stress but more tolerant to ethanol stress. Molecular analysis reveals that in moderate knockdown AtCIB22 mutants, genes including cell redox proteins and stress related proteins are significantly up-regulated, and that in severe knockdown AtCIB22 mu- tants, the alternative respiratory pathways including NDA1, NDB2, AOXla and AtPUMP1 are remarkably elevated. These data demon- strate that AtCIB22 is essential for plant development and mitochondrial electron transport chains in Arabidopsis. Our findings also en- hance our understanding about the physiological role of Complex I in plants.展开更多
The present study involved a questionnaire survey of 156 mothers that gave birth to children with neural tube defects or had a history of pregnancy resulting in children with neural tube defects （case group） and 156...The present study involved a questionnaire survey of 156 mothers that gave birth to children with neural tube defects or had a history of pregnancy resulting in children with neural tube defects （case group） and 156 control mothers with concurrent healthy children （control group） as well as detection of mitochondrial membrane transporter protein gene [uncoupling protein 2 （UCP2）] polymorphism. The maternal UCP2 3＇ untranslated region （UTR） D/D genotype and D allele frequency were significantly higher in the case group compared with the control group （odds ratio （OR） 3.233; 95% confidence interval （C/） 1.103 9.476; P= 0.040; OR： 3.484; 95% CI： for neural tube defects 2.109 5.753; P 〈 0.001）. Univariate and multivariate logistic regression analysis of risk factors for neural tube defects showed that a matemal UCP2 3＇ UTR D/D genotype was negatively interacted with the mothers＇ consumption of frequent fresh fruit and vegetables （S = 0.007）, positively interacted with the mothers＇ frequency of germinated potato consumption （S = 2.15） and positively interacted with the mothers＇ body mass index （S = 3.50）. These findings suggest that maternal UCP2 3＇ UTR gene polymorphism, pregnancy time, consumption of germinated potatoes and body mass index are associated with an increased risk for neural tube defects in children from mothers living in Shanxi province, China. Moreover, there is an apparent gene-environment interaction involved in the development of neural tube defects in offspring.展开更多
基金This project is financially supported by the Henry G Leong Professorship in Neurology(SLH),the Donation Fund for Neurology Research(SLH),and Seed Funding for Basic Research,University of Hong Kong(PWLH)PWL Ho is supported by a Research Assistant ProfessorshipJWM Ho and HF Liu are supported by Postdoctoral Fellowships from the University of Hong Kong.
文摘This review gives a brief insight into the role of mitochondrial dysfunction and oxidative stress in the converging pathogenic processes involved in Parkinson’s disease(PD).Mitochondria provide cellular energy in the form of ATP via oxidative phosphorylation,but as an integral part of this process,superoxides and other reactive oxygen species are also produced.Excessive free radical production contributes to oxidative stress.Cells have evolved to handle such stress via various endogenous anti-oxidant proteins.One such family of proteins is the mitochondrial uncoupling proteins(UCPs),which are anion carriers located in the mitochondrial inner membrane.There are five known homologues(UCP1 to 5),of which UCP4 and 5 are predominantly expressed in neural cells.In a series of previous publications,we have shown how these neuronal UCPs respond to 1-methyl-4-phenylpyridinium(MPP+;toxic metabolite of MPTP)and dopamine-induced toxicity to alleviate neuronal cell death by preserving ATP levels and mitochondrial membrane potential,and reducing oxidative stress.We also showed how their expression can be influenced by nuclear factor kappa-B(NF-B)signaling pathway specifically in UCP4.Furthermore,we previously reported an interesting link between PD and metabolic processes through the protective effects of leptin(hormone produced by adipocytes)acting via UCP2 against MPP+-induced toxicity.There is increasing evidence that these endogenous neuronal UCPs can play a vital role to protect neurons against various pathogenic stresses including those associated with PD.Their expression,which can be induced,may well be a potential therapeutic target for various drugs to alleviate the harmful effects of pathogenic processes in PD and hence modify the progression of this disease.
基金Supported by the Nanjing Health Science and Technology Development Fund,No.YKK24223.
文摘BACKGROUND Uncoupling protein 1(UCP1)plays a pivotal role in modulating energy expen-diture and maintaining metabolic homeostasis within brown and beige adipo-cytes.It has also been implicated in tumorigenesis.AIM To investigate the expression and function of UCP1 in gastric cancer(GC).METHODS UCP1 protein expression in 211 GC tissues was examined using immunohisto-chemistry.Bisulfite sequencing PCR(BSP)was used to detect the methylation status of the UCP1 promoter in GC cell lines and tissues.The relationship between UCP1 expression and clinicopathological parameters was analyzed.CCK8,scratch,transwell,and flow cytometry assays were carried out to analyze the proliferation,migration,invasion,and apoptosis of GC cell lines after knockdown or overexpression of UCP1 in vitro.A nude mouse tumor xenograft model was used to investigate the function of UCP1 in vivo.RNA sequencing,Kyoto Ency-clopedia of Genes and Genomes analysis,and Rap1 pull-down assays were performed to identify the pathway associated with UCP1.RESULTS Loss of UCP1 was significantly associated with gender,poor differentiation,and advanced TNM stage of GC.Hypermethylation of UCP1 was confirmed in GC cells and tumor tissues by BSP.Overexpression of UCP1 suppressed GC cell proliferation,migration,and invasion,and it promoted apoptosis in vitro.UCP1 overexpression also suppressed GC tumor growth in vivo.Moreover,overexpression of UCP1 in GC cells resulted in a significant decrease in active Rap1 protein levels,whereas downregulation of UCP1 markedly enhanced Rap1 activity.CONCLUSION UCP1 downregulation in GC through promoter hypermethylation is related to the progression of GC,indicating that UCP1 plays a role as a tumor suppressor in GC.It regulates Rap1 signaling and may be a potential therapeutic target in GC.
文摘Reactive oxygen species（ROS） are free radicals thought to mediate the neurotoxic effects of several neurodegenerative disorders.In the central nervous system,ROS can also trigger a phenotypic switch in both astrocytes and microglia that further aggravates neurodegeneration,termed reactive gliosis.Negative regulators of ROS,such as mitochondrial uncoupling protein 2（UCP2） are neuroprotective factors that decrease neuron loss in models of stroke,epilepsy,and parkinsonism.However,it is unclear whether UCP2 acts purely to prevent ROS production,or also to prevent gliosis.In this review article,we discuss published evidence supporting the hypothesis that UCP2 is a neuroprotective factor both through its direct effects in decreasing mitochondrial ROS and through its effects in astrocytes and microglia.A major effect of UCP2 activation in glia is a change in the spectrum of secreted cytokines towards a more anti-inflammatory spectrum.There are multiple mechanisms that can control the level or activity of UCP2,including a variety of metabolites and micro RNAs.Understanding these mechanisms will be key to exploitingthe protective effects of UCP2 in therapies for multiple neurodegenerative conditions.
基金Supported by Scientific Research Fund from Jiangsu Province,No.BK2006243National Natural Science Foundation of China,No.30771039
文摘AIM:To detect the expression of mitochondrial uncoupling protein 2(UCP2)in colon cancer and analyze the relation between UCP2 expression and clinical pathological features of colon cancer.METHODS:Fifteen colon tissue samples and 15 its adjacent tissue samples were obtained from colon cancer patients during surgical interventions.UCP2 expression was detected with immunohistochemical method in 10 normal controls,10 hyperplastic polyp patients,20 tubular adenoma patients and 78 colon cancer patients.Patients with rectal cancer were excluded.Quantitative reverse transcription polymerase chain reaction and Western blotting were used to detect UCP2 expressions in colon cancer tissue samples and its adjacent tissue samples.Relation between UCP2 expression and clinical pathological features of colon cancer was also analyzed.RESULTS:The UCP2 mRNA expression level was fourfold higher in colon cancer tissue samples than in its adjacent tissue samples.The UCP2 protein expression level was three-fold higher in colon cancer tissue samples than in its adjacent normal tissue samples.The UCP2 was mainly expressed in cytoplasm.The UCP2 was not expressed in normal colon mucosa.Strong positive staining for UCP2 with a diffuse distribution pattern was identified throughout the mucosa in colon cancer tissue samples with a positive expression rate of 85.9%.The UCP2 expression level was higher in colon cancer tissue samples at clinical stagesⅢandⅣthan in those at stageⅠ+Ⅱ.Univariate analysis showed that the high UCP2 expression level was significantly correlated to colon cancer metastasis(hazard ratio=4.321,confidence interval=0.035-0.682,P=0.046).CONCLUSION:UCP2 is highly expressed in human colon cancer tissue and may be involved in colon cancer metastasis.
基金The item is supported by the National Nature Science Foundation(No.39970923)
文摘Objective:To explore the effects of acupuncture on the expression of uncoupling protein 1（UCP1）gene of brown adipose tissue （BAT）in obese rats.Methods:The expression of UCP1gene ofBAT was determined with RT-PCR technique.The changes of body weight,Lee’s index,body fat,andthe expression of UCP1gene of BAT in obese rats were observed before and after acupuncture.Results:The body weight,Lee’s indeX,body fat in obese rats were all markedly higher than those in normal rats,but the expression of UCP1gene of BAT in obese rats was all lower than that in normal rats.There werenegative correlation between the Obesity index and the expression of UCP1gent in BAT.After acupunc-ture the marked effect of weight loss was achieved while the expression of UCP1gene of BAT Obviously in-creased in obese rats.Conclusion:The abnormal reduction for expression of UCP1gene of BAT might bean important cause for the obesity.To promote the expression of UCP1in obese organism might be an im-portant cellular and mole
基金Supported by Grant from the National Natural Science Foundation of China,No. 30771039
文摘AIM:To investigate whether uncoupling protein 2(UCP2) affects oleic acid-induced secretion of glucagonlike peptide-1(GLP-1) in L-cells.METHODS:mRNA and protein expression of UCP2 were analyzed in human NCI-H716 cells,which serve as a model for enteroendocrine L-cells,by quantitative reverse transcription-polymerase chain reaction and Western blotting before and after treatment with oleic acid.Localization of UCP2 and GLP-1 in NCI-H716 cells was assessed by immunofluorescence labeling.NCI-H716 cells were transiently transfected with a small interfering RNA(siRNA) that targets UCP2(siUCP2) or with a nonspecific siRNA using Lipofectamine 2000.The concentrations of bioactive GLP-1 in the medium were measured by enzyme linked immunosorbent assay.RESULTS:Both GLP-1 and UCP2 granules were expressed mainly in the cytoplasm of NCI-H716 cells.NCI-H716 cells that secreted GLP-1 also expressed UCP2.Time-course experiments revealed that release of GLP-1 from NCI-H716 cells into the medium reached a maximum at 120 min and remained stable until at least 180 min after treatment with oleic acid(the level of GLP-1 increased about 2.3-fold as compared with the level of GLP-1 in the control cells,P < 0.05).In an experiment to determine dose dependence,stimulation of NCI-H716 cells with ≤ 8 mmol oleic acid led to a concentration-dependent release of GLP-1 into the medium;10 mmol oleic acid diminished the release of GLP-1.Furthermore,GLP-1 secretion induced by oleic acid from NCI-H716 cells that were transfected with siUCP2 decreased to 41.8%,as compared with NCI-H716 cells that were transfected with a non-specific siRNA(P < 0.01).CONCLUSION:UCP2 affected GLP-1 secretion induced by oleic acid.UCP2 plays an important role in L-cell secretion that is induced by free fatty acids.
基金a grant from National Natural Sciences Foundation of China (No. 30571764).
文摘The effect of target-directed regulation of the uncoupling protein-2 （UCP-2） gene expression on the ischemia-reperfusion injury of hepatocytes under different conditions was investigated. The expression plasmid and RNAi plasmid targeting UCP-2 gene were constructed and trans- fected into normal hepatocytes and fatty liver cells, respectively. The expression of UCP-2 mRNA was detected by real time PCR. The cells were divided into normal cell group （NCG）, group of normal cells transfected with empty vector （EVNCG）, group of normal cells transfected with expression plasmid （EPNCG）, fatty liver cell group （FCG） and group of fatty liver cells transfected with RNAi plasmid （RPFCG）. The ischemia-reperfusion model in vitro was established. One, 6, 12 and 24 h after reperfusion, Annexin V/PI flow cytometry was used to measure cell necrosis rate, apoptosis rate and survival rate. Simultaneously, the intracellular ATP, ROS and MDA levels were determined. The re- sults showed that 1, 6, 12 and 24 h after ischemia-reperfusion, the intracellular ROS, MDA and ATP levels and cell survival rate in EPNCG were significantly lower, and cell necrosis rate significantly higher than in NCG and EVNCG, but there was no significant difference in apoptosis rate among NCG, EVNCG and EPNCG （P〉005）. Six, 12 and 24 h after reperfusion there was no significant dif- ference in ROS, MDA levels and apoptosis rate between FCG and RPFCG （P〉0.05）, but the ATP level and survival rate of cells in RPFCG were higher than in FCG （P〈0.05）. It was concluded that down-regulation of the UCP-2 gene expression in steatotic hepatocytes could alleviate the ische- mia-reperfusion injury of liver cells.
基金supported by a grant from the Bundesminis-terium für Bildung und Forschung (01ZX1903A)。
文摘Background: Pancreatic ductal adenocarcinoma(PDAC) is a disease of the elderly mostly because its development from preneoplastic lesions depends on the accumulation of gene mutations and epigenetic alterations over time. How aging of non-cancerous tissues of the host affects tumor progression, however, remains largely unknown. Methods: We took advantage of a model of accelerated aging, uncoupling protein 2-deficient( Ucp2 knockout, Ucp2 KO) mice, to investigate the growth of orthotopically transplanted Ucp2 wild-type(WT) PDAC cells(cell lines Panc02 and 6606PDA) in vivo and to study strain-dependent differences of the PDAC microenvironment. Results: Measurements of tumor weights and quantification of proliferating cells indicated a significant growth advantage of Panc02 and 6606PDA cells in WT mice compared to Ucp2 KO mice. In tumors in the knockout strain, higher levels of interferon-γ m RNA despite similar numbers of tumor-infiltrating T cells were observed. 6606PDA cells triggered a stronger stromal reaction in Ucp2 KO mice than in WT animals. Accordingly, pancreatic stellate cells from Ucp2 KO mice proliferated at a higher rate than cells of the WT strain when they were incubated with conditioned media from PDAC cells. Conclusions: Ucp2 modulates PDAC microenvironment in a way that favors tumor progression and implicates an altered stromal response as one of the underlying mechanisms.
基金supported by a grant from the Bundesministerium für Bildung und Forschung(0315892A,GERONTOSYS program)
文摘BACKGROUND： Uncoupling protein 2 （UCP2） has been suggested to inhibit mitochondrial production of reactive oxygen species （ROS） by decreasing the mitochondrial membrane potential. Experimental acute pancreatitis is associated with increased UCP2 expression, whereas UCP2 deficiency retards regeneration of aged mice from acute pancreatitis. Here, we have addressed biological and molecular functions of UCP2 in pancreatic stellate cells （PSCs）, which are involved in pancreatic wound repair and fibrogenesis. METHODS： PSCs were isolated from 12 months old （aged） UCP2^-/- mice and animals of the wild-type （WT） strain C57BL/6. Proliferation and cell death were assessed by em- ploying trypan blue staining and a 5-bromo-2＇-deoxyuridine incorporation assay. Intracellular fat droplets were visualized by oil red O staining. Levels of mRNA were determined by RT-PCR, while protein expression was analyzed by immunoblotting and immunofluorescence analysis. Intracellular ROS levels were measured with 2＇,7＇-dichlorofluorescin diacetate. Expression of senescence-associated β-galactosidase （SA β-Gal） was used as a surrogate marker of cellular senescence. RESULTS： PSCs derived from UCP2^-/- mice proliferated at a lower rate than cells from WT mice. In agreement with this observation, the UCP2 inhibitor genipin displayed dose- dependent inhibitory effects on WT PSC growth. Interestingly, ROS levels in PSCs did not differ between the two strains, and PSCs derived from UCP2^-/- mice did not senesce faster than those from corresponding WT cells. PSCs from UCP2^-/- mice and WT animals were also indistinguishable with respect to the activation-dependent loss of intracellular fat droplets, expression of the activation marker α-smooth muscle actin, type I collagen and the autocrine/paracrine mediators interleukin-6 and transforming growth factor-I~ 1. CONCLUSIONS： A reduced proliferative capacity of PSC from aged UCP2^-/- mice may contribute to the retarded regeneration after acute pancreatitis. Apart from their slower growth, PSC of UCP2^-/- mice displayed no functional abnormalities. The antifibrotic potential of UCP2 inhibitors deserves further attention.
文摘Uncoupling protein 1 (UCP1) expressed by the brown adipose tissue (BAT) in the mitochondrial crista acts as a homeostatic thermogenerator of eutherians. The evaluation of UCP1 expression in the BAT offers significant scientific insight, especially in studies targeting limited areas such as the periarterial and pericardial regions of small experimental mammals. However, the negligible amount of this adipose tissue would render the general quantitative evaluation of the protein unreliable because of lipid contamination and low protein concentration. To address this problem, we quantitatively evaluated UCP1 expression in the mitochondrion of the mouse interscapular BAT using immunoelectron microscopy and immunohistochemical studies using a combination of primary and secondary antibodies in scheme A (rabbit anti-UCP1 IgG/gold particle-conjugated goat anti-rabbit IgG), B (rabbit IgG/gold particle-conjugated goat anti-rabbit IgG), C (rabbit anti-UCP1 IgG/gold particle-unconjugated goat anti-rabbit IgG), and D (rabbit IgG/gold particle-unconjugated goat anti-rabbit IgG). Scheme A shows the immunopositive reaction of obvious gold particles in the mitochondrial area, whereas other procedures revealed less distinctive reactions. The distinctive gold particle immunoreaction comprised electrical high-density spots with a mean diameter of >5 nm. However, in scheme B, the electrical high-density spots were scattered outside the mitochondrion and were significantly smaller than 4 nm;schemes C and D demonstrated few immunoreactions. Logistic regression analysis between schemes A and B showed that the threshold diameter of the electrical high-density spots measuring >5 nm indicated a true positive immunoreaction to anti-UCP1 antibody specifically in the mitochondrial area. Minor statistical difference was observed in the primary anti-UCP1 antibody between polyclonal IgG and monoclonal antibodies. Therefore, immunoelectron microscopy might be useful for evaluating negligible protein expression in some limited areas, such as UCP1 expression in the BAT of small experimental animals.
文摘Cardiogenic shock is the leading cause of death among patients hospitalized with acute myocardial infarction （MI）. Understanding the mechanisms for acute pump failure is therefore important. The aim of this study is to examine in an acute MI dog model whether mitochondrial bio-energetic function within non-ischemic wall regions are associated with pump failure. Anterior MI was produced in dogs via ligation of left anterior descending （LAD） coronary artery, that resulted in an infract size of about 30% of the left ventricular wall. Measurements ofhemodynamic status, mitochondrial function, free radical production and mitochondrial uncoupling protein 3 （UCP3） expression were determined over 24 h period. Hemodynamic measurements revealed a 〉 50% reduction in cardiac output at 24 h post infarction when compared to baseline. Biopsy samples were obtained from the posterior non-ischemic wall during acute infarction. ADP/O ratios for isolated mitochondria from non-ischemic myocardium at 6 h and 24 h were decreased when compared to the ADP/O ratios within the same samples with and without palmitic acid （PA）. GTP inhibition of （PA）-stimulated state 4 respiration in isolated mitochondria from the non-ischemic wall increased by 7% and 33% at 6 h and 24 h post-infarction respectively when compared to sham and pre-infarction samples. This would suggest that the mitochondria are uncoupled and this is supported by an associated increase in UCP3 expression observed on western blots from these same biopsy samples. Blood samples from the coronary sinus measured by electron paramagnetic resonance （EPR） methods showed an increase in reactive oxygen species （ROS） over baseline at 6 h and 24 h post-infarction. In conclusion, mitochondrial bio-energetic ADP/O ratios as a result of acute infarction are abnormal within the non-ischemic wall. Mitochondria appear to be energetically uncoupled and this is associated with declining pump function. Free radical production may be associated with the induction of uncoupling proteins in the mitochondria.
基金This study was financially supported by grants from the National Natural Science Foundation of China(No.31971420,32171497).
文摘Extreme hot weather is occurring more frequently due to global warming,posing a significant threat to species survival.Birds in particular are more likely to overheat in hot weather because they have a higher body temperature.This study used a heat stress model to investigate the antioxidant defense mechanisms and changes in fatty acid catabolism in Red-billed Leiothrix(Leiothrix lutea)to gain an understanding of how birds adapt to high temperatures.The birds were divided into five groups:a control group(30℃for 0 days),1 D group(40℃for 1 day),3 D group(40℃for 3 days),14 D group(40℃for 14 days)and recovery group(40℃for 14 days,then 30℃for 14 days).Our results indicated that when Red-billed Leiothrix are subjected to heat stress,malondialdehyde(MDA)content in the liver significantly increased,as did the enzyme activities of catalase(CAT),glutathione-SH-peroxidase(GSH-PX)and total antioxidant capacity(T-AOC)in the liver.Furthermore,there was a significant increase in heat shock protein 70(HSP70)expression in the liver,while avian uncoupling protein(avUCP)expression in muscle was significantly reduced.Additionally,there was a significant reduction in fatty acid catabolism enzyme activity such as 3-hydroxyacyl-CoAdehydrogenase(HOAD)activity in the heart,and carnitine palmitoyl transferase 1(CPT-1)and citrate synthase(CS)activity in the heart and liver.Furthermore,fatty acid translocase(FAT/CD36)in the heart,heart-type fatty acid binding protein(H-FABP)and fatty acid binding protein(FABP-pm)in the liver and heart were also significantly decreased.These changes reverted after treatment,but not to the same level as the control group.Our results indicated that when Red-billed Leiothrix are exposed to heat stress their internal antioxidant defense system is activated to counteract the damage caused by high temperatures.However,even with high antioxidant levels,prolonged high temperature exposure still caused some degree of oxidative damage possibly requiring a longer recovery time.Additionally,Red-billed Leiothrix may be able to resist heat stress by reducing fatty acid transport and catabolism.
基金National Natural Science Foundation of China,No.81370008 and No.81000169Natural Science Foundation of Zhejiang Province,No.R2110159,No.LY15H030006 and No.LY16H030003
文摘AIM To investigate the role of the miR-133a-UCP2 pathway in the pathogenesis of inflammatory bowel disease (IBD) and to explore the potential downstream mechanisms with respect to inflammation, oxidative stress and energy metabolism. METHODS C57BL/6 mice were fed dextran sulfate sodium (DSS) liquid for 7 consecutive days, followed by the administration of saline to the DSS group, UCP2 siRNA to the UCP2 group and a miR-133a mimic to the miR-133a group on days 8 and 11. Body weight, stool consistency and rectal bleeding were recorded daily, and these composed the disease activity index (DAI) score for the assessment of disease severity. After cervical dislocation was performed on day 14, the length of the colon in each mouse was measured, and colonic tissue was collected for further study, which included the following: haematoxylin and eosin staining, UCP2 and miR-133a detection by immunohistochemical staining, western blot and quantitative real-time PCR, measurement of apoptosis by TUNEL assay, and the assessment of inflammation (TNF-alpha, IL-1 beta, IL-6 and MCP1), oxidative stress (H2O2 and MDA) and metabolic parameters (ATP) by ELISA and colorimetric methods. RESULTS An animal model of IBD was successfully established, as shown by an increased DAI score, shortened colon length and specific pathologic changes, along with significantly increased UCP2 and decreased miR-133a levels. Compared with the DSS group, the severity of IBD was alleviated in the UCP2 and the miR-133a groups after successful UCP2 knockdown and miR-133a overexpression. The extent of apoptosis, as well as the levels of TNF-alpha, IL-1 beta, MDA and ATP, were significantly increased in both the UCP2 and miR-133a groups compared with the DSS group. CONCLUSION The miR-133a-UCP2 pathway participates in IBD by altering downstream inflammation, oxidative stress and markers of energy metabolism, which provides novel clues and potential therapeutic targets for IBD.
基金the Special Research Fund(BOF)of Ghent University(Belgium)for the financial support of Abdol ah Akbarian(grant number 01SF2711)
文摘Heat as a stressor of poultry has been studied extensively for many decades; it affects poultry production on a worldwide basis and has significant impact on well-being and production. More recently, the involvement of heat stress in inducing oxidative stress has received much interest. Oxidative stress is defined as the presence of reactive species in excess of the available antioxidant capacity of animal cells. Reactive species can modify several biologically cellular macromolecules and can interfere with cell signaling pathways. Furthermore, during the last decade, there has been an ever-increasing interest in the use of a wide array of natural feed-delivered phytochemicals that have potential antioxidant properties for poultry. In light of this, the current review aims to（1） summarize the mechanisms through which heat stress triggers excessive superoxide radical production in the mitochondrion and progresses into oxidative stress,（2） illustrate that this pathophysiology is dependent on the intensity and duration of heat stress,（3） present different nutritional strategies for mitigation of mitochondrial dysfunction, with particular focus on antioxidant phytochemicals.Oxidative stress that occurs with heat exposure can be manifest in all parts of the body; however, mitochondrial dysfunction underlies oxidative stress. In the initial phase of acute heat stress, mitochondrial substrate oxidation and electron transport chain activity are increased resulting in excessive superoxide production. During the later stage of acute heat stress, down-regulation of avian uncoupling protein worsens the oxidative stress situation causing mitochondrial dysfunction and tissue damage. Typically, antioxidant enzyme activities are upregulated. Chronic heat stress, however, leads to downsizing of mitochondrial metabolic oxidative capacity, up-regulation of avian uncoupling protein, a clear alteration in the pattern of antioxidant enzyme activities, and depletion of antioxidant reserves.Some phytochemicals, such as various types of flavonoids and related compounds, were shown to be beneficial in chronic heat-stressed poultry, but were less or not effective in non-heat-stressed counterparts. This supports the contention that antioxidant phytochemicals have potential under challenging conditions. Though substantial progress has been made in our understanding of the association between heat stress and oxidative stress, the means by which phytochemicals can alleviate oxidative stress have been sparsely explored.
基金supported by grant NoMSM0021620849 given by the Ministry of Education,Youth and Sports of the Czech Republicby project PRVOUK-P26/LF1/4given by Charles University in Prague+1 种基金by grant No. SVV-2012-264514 from Charles University in Pragueby grant No.41310 given by the Grant Agency of Charles University in Prague,Czech Republic
文摘Distribution and activity of mitochondda are key factors in neuronal development, synaptic plasticity and axogenesis. The majority of energy sources, necessary for cellular functions, originate from oxidative phosphorylation located in the inner mitochondrial membrane. The adenosine-5＇- triphosphate production is regulated by many control mechanism-firstly by oxygen, substrate level, adenosine-5＇-diphosphate level, mitochondrial membrane potential, and rate of coupling and proton leak. Recently, these mechanisms have been implemented by ＂second control mechanisms,＂ such as reversible phosphorylation of the tricarboxylic acid cycle enzymes and electron transport chain complexes, aUosteric inhibition of cytochrome c oxidase, thyroid hormones, effects of fatty acids and uncoupling proteins. Impaired function of mitochondria is implicated in many diseases ranging from mitochondrial myopathies to bipolar disorder and schizophrenia. Mitochondrial dysfunctions are usually related to the ability of mitochondria to generate adenosine-5＇-triphosphate in response to energy demands. Large amounts of reactive oxygen species are released by defective mitochondria similarly, decline of antioxidative enzyme activities （e.g. in the elderly） enhances reactive oxygen species production. We reviewed data concerning neuroplasticity, physiology, and control of mitochondrial oxidative phosphorylation and reactive oxygen species production.
基金supported by the National Natural Science Foundation of China[31872674]the Jilin Talent Development Foundation Grant[20200301018RQ]the Fundamental Research Funds for the Central Universities[CGZH202206].
文摘Obesity-induced type 2 diabetes is mainly due to excessive free fatty acids leading to insulin resistance.Increasing thermogenesis is regarded as an effective strategy for hypolipidemia and hypoglycemia.Ginsenoside is a natural active component in Panax ginseng C.A.Meyer,and some of them enhance thermogenesis.However,there are few studies on the mechanism and target of ginsenosides enhancing thermogenesis.Using thermogenic protein uncoupling protein 1(UCP1)-luciferase reporter assay,we identifi ed ginsenoside F1 as a novel UCP1 activator in the ginsenosides library.Using pull down assay and inhibitor interference,we found F1 binds toβ3-adrenergic receptors(β3-AR)to enhance UCP1 expression via cAMP/PKA/CREB pathway.We also investigated the ability of F1 on energy metabolism in obesity-induced diabetic mice,including body weight,body composition and energy expenditure.The results of proteomics showed that F1 signifi cantly up-regulated thermogenesis proteins and lipolytic proteins,but down-regulated fatty acid synthesis proteins.Ginsenoside F1 increased thermogenesis and ameliorated insulin resistance specifi cally by promoting the browning of white adipose tissue in obese mice.Additionally,ginsenoside F1 improves norepinephrine-induced insulin resistance in adipocytes and hepatocytes,and shows a stronger mitochondria respiration ability than norepinephrine.These fi ndings suggest that ginsenoside F1 is a promising lead compound in the improvement of insulin resistance.
基金supported by grants from the Natural Science Foundation of Hubei province (No. 2010CDB08005)the National Natural Science Foundation of China (No. 30730094 and81000409)Special Funds for State Key Development Program for Basic Research of China (973 Program) (No.2011CB504504)
文摘Mitochondrial DNA(mtDNA) common deletion(CD) plays a significant role in aging and age-related diseases.In this study,we used D-galactose(D-gal) to generate an animal model of aging and the involvement and causative mechanisms of mitochondrial damage in such a model were investigated.Twenty 5-week-old male Sprague-Dawley rats were randomly divided into two groups:D-gal group(n=10) and control group(n=10).The quantity of the mtDNA CD in the hippocampus was determined using a TaqMan real-time PCR assay.Transmission electron microscopy was used to observe the mitochondrial ultrastructure in the hippocampus.Western blot was used to detect the protein levels of NADPH oxidase(NOX) and uncoupling protein 2(UCP2).We found that the level of mtDNA CD was significantly higher in the hippocampus of D-gal-induced aging rats than in control rats.In comparison with the control group,the mitochondrial ultrastructure in the hippocampus of D-gal-treated rats was damaged,and the protein levels of NOX and UCP2 were significantly increased in the hippocampus of D-gal-induced aging rats.This study demonstrated that the levels of mtDNA CD and NOX protein expression were significantly increased in the hippocampus of D-gal-induced aging rats.These findings indicate that NOX-dependent reactive oxygen species generation may contribute to D-gal-induced mitochondrial damage.
基金Supported by the Earmarked Fund for Modern Agro-industry Technology Research System(CARS-42)Program for Innovation Research Team in University of Heilongjiang Province(2010td02)
文摘The uncoupling protein(UCP)is a member of the mitochondrial membrane transporter family,which plays an important role in energy metabolism.In the present study,the UCP gene was considered as a candidate gene for chicken growth traits,and the association of UCP gene SNPs with growth rate was investigated in the eighth generation of NEAUHLF broiler lines.Two SNPs were found in chicken UCP gene,and the association analysis results showed that both the individual and combination of chicken UCPgene SNPs were significantly associated with body weight of 7 weeks(BW7)and carcass weight(CW)(P〈0.05),and the combination had much significant effects than the single SNP.This research suggested that the UCP gene could be a candidate gene or linked to a major gene which affected growth traits in chicken.
基金supported by the National Basic Research Program of China (No. 2009CB941503)
文摘Complex I （the NADH：ubiquinone oxidoreductase） of the mitochondrial respiratory chain is a complicated, multi-subunit, membrane- bound assembly and contains more than 40 different proteins in higher plants. In this paper, we characterize the Arabidopsis homologue （designated as AtCIB22） of the B22 subunit of eukaryotic mitochondriai Complex I. AtCIB22 is a single-copy gene and is highly con- served throughout eukaryotes. AtCIB22 protein is located in mitochondria and the AtC1B22 gene is widely expressed in different tissues. Mutant Arabidopsis plants with a disrupted AtC1B22 gene display pleiotropic phenotypes including shorter roots, smaller plants and de- layed flowering. Stress analysis indicates that the AtC1B22 mutants＇ seed germination and early seedling growth are severely inhibited by sucrose deprivation stress but more tolerant to ethanol stress. Molecular analysis reveals that in moderate knockdown AtCIB22 mutants, genes including cell redox proteins and stress related proteins are significantly up-regulated, and that in severe knockdown AtCIB22 mu- tants, the alternative respiratory pathways including NDA1, NDB2, AOXla and AtPUMP1 are remarkably elevated. These data demon- strate that AtCIB22 is essential for plant development and mitochondrial electron transport chains in Arabidopsis. Our findings also en- hance our understanding about the physiological role of Complex I in plants.
基金sponsored by the National Natural Science Foundation of China, No. 31140012, 31040056,31140079the Natural Science Foundation of Shanxi Province,No. 2006011113
文摘The present study involved a questionnaire survey of 156 mothers that gave birth to children with neural tube defects or had a history of pregnancy resulting in children with neural tube defects （case group） and 156 control mothers with concurrent healthy children （control group） as well as detection of mitochondrial membrane transporter protein gene [uncoupling protein 2 （UCP2）] polymorphism. The maternal UCP2 3＇ untranslated region （UTR） D/D genotype and D allele frequency were significantly higher in the case group compared with the control group （odds ratio （OR） 3.233; 95% confidence interval （C/） 1.103 9.476; P= 0.040; OR： 3.484; 95% CI： for neural tube defects 2.109 5.753; P 〈 0.001）. Univariate and multivariate logistic regression analysis of risk factors for neural tube defects showed that a matemal UCP2 3＇ UTR D/D genotype was negatively interacted with the mothers＇ consumption of frequent fresh fruit and vegetables （S = 0.007）, positively interacted with the mothers＇ frequency of germinated potato consumption （S = 2.15） and positively interacted with the mothers＇ body mass index （S = 3.50）. These findings suggest that maternal UCP2 3＇ UTR gene polymorphism, pregnancy time, consumption of germinated potatoes and body mass index are associated with an increased risk for neural tube defects in children from mothers living in Shanxi province, China. Moreover, there is an apparent gene-environment interaction involved in the development of neural tube defects in offspring.
