共查询到20条相似文献,搜索用时 15 毫秒
1.
Di Santo S Diehm N Ortmann J Völzmann J Yang Z Keo HH Baumgartner I Kalka C 《Biochemical and biophysical research communications》2008,373(4):528-532
Background
Oxidized low density lipoprotein (oxLDL) has been shown to induce apoptosis and senescence of endothelial progenitor cells (EPC). In the present study, we hypothesized that even sub-apoptotic concentrations of oxLDL impair the angiogenic potential of EPC and investigated if this effect is mediated by affecting adhesion and incorporation.Methods
A co-culture system of human microvascular endothelial cells and EPC was used to study the effect of sub-apoptotic concentrations of native (nLDL) and oxLDL on cell-cell interaction. The expression and the functional role of angiogenic adhesion molecules and integrins was monitored by FACS and neutralizing assay, respectively.Results
We observed an inhibition of tube formation and impairment of EPC integration into the vascular network of mature endothelial cells by oxLDL. In contrast, nLDL did not affect angiogenic properties of EPC. Incubation of EPC with sub-apoptotic oxLDL concentrations significantly decreased E-selectin and integrin αvβ5 expression (37.6% positive events vs. 71.5% and 24.3% vs. 49.9% compared to control culture media without oxLDL). Interestingly, expression of αvβ3, VE-cadherin and CD31 remained unchanged. Blocking of E-selectin and integrin αvβ5 by neutralizing antibody effectively inhibited adhesion of EPC to differentiated endothelial cells (56.5% and 41.9% of control; p < 0.001).Conclusion
In conclusion, oxidative alteration of LDL impairs angiogenic properties of EPC at sub-apoptotic levels by downregulation of E-selectin and integrin αvβ5, both substantial mediators of EPC-endothelial cell interaction. 相似文献2.
Valdecir F. Ximenes Adriano S. PessoaCamila Z. Padovan Daniele C. AbrantesFabiana Helena F. Gomes Michele A. MaticoliManoel L. de Menezes 《Biochimica et Biophysica Acta (BBA)/General Subjects》2009
Background
Melatonin is well-established as a powerful reducing agent of oxidant generated in the cell medium. We aimed to investigate how readily melatonin is oxidized by peroxyl radicals ROO⋅ generated by the thermolysis of 2,2′-azobis(2-amidinopropane) hydrochloride (AAPH) and the role of glutathione (GSH) during the reaction course.Methods
Chromatographic, mass spectroscopy, and UV–visible spectrometric techniques were used to study the oxidation of melatonin by ROO⋅ or horseradish peroxidase (HRP)/H2O2. Our focus was the characterization of products and the study of features of the reaction.Results
We found that N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK) and a monohydroxylated derivative of melatonin were the main products of the reaction between melatonin and ROO⋅. Higher pH or saturation of the medium with molecular oxygen increased the yield of AFMK but did not affect the reaction rate. Melatonin increased the depletion of intracellular GSH mediated by AAPH. Using the HRP/H2O2 as the oxidant system, the addition of melatonin promoted the oxidation of GSH to GSSG.Conclusions
These results show, for the first time, that melatonin radical is able to oxidize GSH.General significance
We propose that this new property of melatonin could explain or be related to the recently reported pro-oxidant activities of melatonin. 相似文献3.
Elkan AC Sjöberg B Kolsrud B Ringertz B Hafström I Frostegård J 《Arthritis research & therapy》2008,10(2):R34
Introduction
The purpose of this study was to investigate the effects of vegan diet in patients with rheumatoid arthritis (RA) on blood lipids oxidized low-density lipoprotein (oxLDL) and natural atheroprotective antibodies against phosphorylcholine (anti-PCs).Methods
Sixty-six patients with active RA were randomly assigned to either a vegan diet free of gluten (38 patients) or a well-balanced non-vegan diet (28 patients) for 1 year. Thirty patients in the vegan group completed more than 3 months on the diet regimen. Blood lipids were analyzed by routine methods, and oxLDL and anti-PCs were analyzed by enzyme-linked immunosorbent assay. Data and serum samples were obtained at baseline and after 3 and 12 months.Results
Mean ages were 50.0 years for the vegan group and 50.8 years for controls. Gluten-free vegan diet induced lower body mass index (BMI) and low-density lipoprotein (LDL) and higher anti-PC IgM than control diet (p < 0.005). In the vegan group, BMI, LDL, and cholesterol decreased after both 3 and 12 months (p < 0.01) and oxLDL after 3 months (p = 0.021) and trendwise after 12 months (p = 0.090). Triglycerides and high-density lipoprotein did not change. IgA anti-PC levels increased after 3 months (p = 0.027) and IgM anti-PC levels increased trendwise after 12 months (p = 0.057). There was no difference in IgG anti-PC levels. In the control diet group, IgM anti-PC levels decreased both after 3 and 12 months (p < 0.01). When separating vegan patients into clinical responders and non-responders at 12 months, the effects on oxLDL and anti-PC IgA were seen only in responders (p < 0.05).Conclusion
A gluten-free vegan diet in RA induces changes that are potentially atheroprotective and anti-inflammatory, including decreased LDL and oxLDL levels and raised anti-PC IgM and IgA levels. 相似文献4.
Aurelia Sima Maxime Parisotto Sylvie Mader Pangala V. Bhat 《Biochimica et Biophysica Acta (BBA)/General Subjects》2009,1790(12):1660-1664
Background
Retinal dehydrogenases (RALDHs) catalyze the dehydrogenation of retinal into retinoic acids (RAs), which are required for embryogenesis and tissue differentiation. This study sought to determine the detailed kinetic properties of 2 mouse RALDHs, namely RALDH3 and 4, for retinal isomer substrates, to better define their specificities in RA isomer synthesis.Methods
RALDH3 and 4 were expressed in Escherichia coli as His-tagged proteins and affinity-purified. Enzyme kinetics were performed with retinal isomer substrates. The enzymatic products were analyzed by high pressure liquid chromatography.Results
RALDH3 oxidized all-trans retinal with high catalytic efficiency (Vmax/Km = 77.9) but did not show activity for either 9-cis or 13-cis retinal substrates. On the other hand, RALDH4 was inactive for all-trans retinal substrate, exhibited high activity for 9-cis retinal oxidation (Vmax/Km = 27.4), and oxidized 13-cis retinal with lower catalytic efficiency (Vmax/Km = 8.24). β-ionone, a potent inhibitor of RALDH4 activity, suppressed 9-cis and 13-cis retinal oxidation competitively with inhibition constants of 0.60 and 0.32, respectively, but had no effect on RALDH3 activity. The divalent cation MgCl2 activated 13-cis retinal oxidation by RALDH4 by 3-fold, did not significantly influence 9-cis retinal oxidation, and slightly activated RALDH3 activity.Conclusions
These data extend the kinetic characterization of RALDH3 and 4, providing their specificities for retinal isomer substrates.General significance
The kinetic characterization of RALDHs should give useful information in determining amino acid residues that are involved in the specificity for retinal isomers and on the role of these enzymes in the synthesis of RAs in specific tissues. 相似文献5.
6.
Hema S. Aluri David C. Simpson Jeremy C. Allegood Ying Hu Karol Szczepanek Scott Gronert Qun Chen Edward J. Lesnefsky 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
Cytochrome c (Cyt c) is a mobile component of the electron transport chain (ETC.) which contains a tightly coordinated heme iron. In pathologic settings, a key ligand of the cyt c's heme iron, methionine (Met80), is oxidized allowing cyt c to participate in reactions as a peroxidase with cardiolipin as a target. Myocardial ischemia (ISC) results in ETC. blockade and increased production of reactive oxygen species (ROS). We hypothesized that during ischemia–reperfusion (ISC-REP); ROS generation coupled with electron flow into cyt c would oxidize Met80 and contribute to mitochondrial-mediated ETC. damage.Methods
Mitochondria were incubated with specific substrates and inhibitors to test the contributions of ROS and electron flow into cyt c. Subsequently, cyt c and cardiolipin were analyzed. To test the pathophysiologic relevance, mouse hearts that underwent ISC-REP were tested for methionine oxidation in cyt c.Results
The combination of substrate/inhibitor showed that ROS production and electron flux through cyt c are essential for the oxidation of methionine residues that lead to cardiolipin depletion. The content of cyt c methionine oxidation increases following ISC-REP in the intact heart.Conclusions
Increase in intra-mitochondrial ROS coupled with electron flow into cyt c, oxidizes cyt c followed by depletion of cardiolipin. ISC-REP increases methionine oxidation, supporting that cyt c peroxidase activity can form in the intact heart.General significance
This study identifies a new site in the ETC. that is damaged during cardiac ISC-REP. Generation of a neoperoxidase activity of cyt c favors the formation of a defective ETC. that activates signaling for cell death. 相似文献7.
Olfa Dridi Gargouri Boutheina GargouriSouhel Kallel Trabelsi Mohamed BouazizRidha Abdelhédi 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
A kinetic study of the electrochemical oxidation of syringic acid (3,5-dimethoxy-4-hydroxybenzoic acid) by cyclic voltammetry at treated gold disk was combined with results of electrolyses at Ta/PbO2 anode in order to convert it into potentially high-added-value product.Methods
The electrochemical oxidation of syringic acid was carried out in order to convert this compound to 3-O-methylgallic acid. This latter was identified by mass spectrophotometry using LC-MS/MS apparatus. The 3-O-methylgallic acid synthesis was controlled by cyclic volammetry, Ortho-diphenolicdeterminations and DPPH radical-scavenging activity.Results
The proposed mechanism is based on the hypothesis of a bielectronic discharge of syringic acid molecule under free and adsorbed form involving two intermediate cation mesomers. Hydrolysis of the more stable of this last one leads to the formation of the 3,4-dihydroxy-5-methoxybenzoic acid (3-O-methylgallic acid) as a major product. The latter aromatic compound was synthesized by anodic oxidation of syringic acid at PbO2 electrode. The cyclic voltammogram of the electrolysis bath of syringic acid shows that the anodic peak potential of 3-O-methylgallic acid was lower (Epa = 128 mV) than that of SA (Epa = 320 mV). And the strongest antiradical activity was detected when the 3-O-methylgallic acid concentration was higher".Conclusion
The electrochemical oxidation using PbO2 anode is a rapid, simple and efficient method tool for a conversion of SA into 3-O-methylgallic acid, a potent antioxidant derivativeGeneral Significance
The electrochemical process consists in a simple transformation of the syringic acid into 3-O-methylgallic acid having a better antioxidant capacity. This result has been justified by cyclic voltametry which shows that anodic peak of 3-O-methylgallic acid is reversible. Furthermore, its potential is lower than that of the irreversible anodic peak of syringic acid to 3-O-methylgallic acid. 相似文献8.
Aims
Our previous studies revealed that echinocystic acid (EA) showed obvious attenuation of atherosclerosis in rabbits fed a high-fat diet. However, the underlying mechanisms remain to be elucidated. Considering the importance of endothelial progenitor cells (EPCs) in atherosclerosis, we hypothesise that EPCs may be one of the targets for the anti-atherosclerotic potential of EA.Main methods
After in vitro cultivation, EPCs were exposed to 100 μg/mL of oxidised low-density lipoprotein (oxLDL) and incubated with or without EA (5 and 20 μM) for 48 h. An additional two groups of EPCs (oxLDL + 20 μM EA) were pre-treated with either wortmannin, an inhibitor of the phosphoinositide 3-kinase (PI3K) pathway, or nitro-l-arginine methyl ester (l-NAME), an endothelial nitric oxide synthase (eNOS)-specific inhibitor. Assessment of EPC apoptosis, adhesion, migration, and nitric oxide (NO) release was performed using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) staining, cell counting, caspase-3 activity assay, transwell chamber assay, and Griess reagent, respectively. The protein expression of protein kinase B (Akt) and eNOS was detected using Western blot.Key findings
Treatment of EPCs with oxLDL induced significant apoptosis and impaired adhesion, migration, and NO production. The deleterious effects of oxLDL on EPCs were attenuated by EA. However, when EPCs were pre-treated with wortmannin or l-NAME, the effects of EA were abrogated. Additionally, oxLDL significantly down-regulated eNOS protein expression as well as repression of eNOS and Akt phosphorylation.Significance
The inhibitory effect of oxLDL on Akt/eNOS phosphorylation was attenuated by EA. Taken together, the results indicate that EA protects EPCs from damage caused by oxLDL via the Akt/eNOS pathway. 相似文献9.
10.
Xiu-Zhen Wu Ai-Xia Cheng Ling-Mei Sun Shu-Juan Sun Hong-Xiang Lou 《Biochimica et Biophysica Acta (BBA)/General Subjects》2009
Background
Plagiochin E (PLE) is an antifungal macrocyclic bis(bibenzyl) isolated from liverwort Marchantia polymorpha L. Its antifungal mechanism is unknown. To elucidate the mechanism of action, its effect on mitochondria function in Candida albicans was studied.Methods
We assayed the mitochondrial membrane potential (mtΔψ) using rhodamine 123, measured ATP level in mitochondria by HPLC, and detected the activities of mitochondrial F0F1-ATPase and dehydrogenases. Besides, the mitochondrial dysfunction-induced reactive oxygen species (ROS) production was determined by a fluorometric assay, and the effects of antioxidant L-cysteine on PLE-induced ROS production and the antifungal effect of PLE on C. albicans were also investigated.Results
Exposure to PLE resulted in an elevation of mtΔψ, and a decrease of ATP level in mitochondria. The ATP depletion owed to PLE-induced enhancement of mitochondrial F0F1-ATPase and inhibition of the mitochondrial dehydrogenases. These dysfunctions of mitochondria caused ROS accumulation in C. albicans, and this increase in the level of ROS production and PLE-induced decrease in cell viability were prevented by addition of L-cysteine, indicating that ROS was an important mediator of the antifungal action of PLE.Conclusions
PLE exerts its antifungal activity through mitochondrial dysfunction-induced ROS accumulation in C. albicans.General significance
The effect of PLE on the mitochondria function in C. albicans was assayed for the first time. These results would conduce to elucidate its underlying antifungal mechanism. 相似文献11.
Young-Jun Park Sung-Jin Yoon Hee-Bong Lee 《Biochimica et Biophysica Acta (BBA)/General Subjects》2010
Background
Dienelactone hydrolases catalyze the hydrolysis of dienelactone to maleylacetate, which play a key role for the microbial degradation of chloroaromatics via chlorocatechols. Here, a thermostable dienelactone hydrolase from thermoacidophilic archaeon Sulfolobus solfataricus P1 was the first purified and characterized and then expressed in Escherichia coli.Methods
The enzyme was purified by using several column chromatographys and characterized by determining the enzyme activity using p-nitrophenyl caprylate and dienelactones. In addition, the amino acids related to the catalytic mechanism were examined by site-directed mutagenesis using the identified gene.Results
The enzyme, approximately 29 kDa monomeric, showed the maximal activity at 74 °C and pH 5.0, respectively. The enzyme displayed remarkable thermostability: it retained approximately 50% of its activity after 50 h of incubation at 90 °C, and showed high stability against denaturing agents, including various detergents, urea, and organic solvents. The enzyme displayed substrate specificities toward trans-dienelactone, not cis-isomer, and also carboxylesterase activity toward p-nitrophenyl esters ranging from butyrate (C4) to laurate (C12). The kcat/Km ratios for trans-dienelactone and p-nitrophenyl caprylate (C8), the best substrate, were 92.5 and 54.7 s−1 μM−1, respectively.Conclusions
The enzyme is a typical dienelactone hydrolase belonging to α/β hydrolase family and containing a catalytic triad composed of Cys151, Asp198, and His229 in the active site.General significance
The enzyme is the first characterized archaeal dienelactone hydrolase. 相似文献12.
Salvatore Nesci Vittoria VentrellaFabiana Trombetti Maurizio PiriniAlessandra Pagliarani 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
The macrolide antibiotics oligomycin, venturicidin and bafilomycin, sharing the polyketide ring and differing in the deoxysugar moiety, are known to block the transmembrane ion channel of ion-pumping ATPases; oligomycins are selective inhibitors of mitochondrial ATP synthases.Methods
The inhibition mechanism of macrolides was explored on swine heart mitochondrial F1FO-ATPase by kinetic analyses. The amphiphilic membrane toxicant tributyltin (TBT) and the thiol reducing agent dithioerythritol (DTE) were used to elucidate the nature of the macrolide–enzyme interaction.Results
When individually tested, the macrolide antibiotics acted as uncompetitive inhibitors of the ATPase activity. Binary mixtures of macrolide inhibitors I1 and I2 pointed out a non-exclusive mechanism, indicating that each macrolide binds to its binding site on the enzyme. When co-present, the two macrolides acted synergistically in the formed quaternary complex (ESI1I2), thus mutually strengthening the enzyme inhibition. The enzyme inhibition by macrolides displaying a shared mechanism was dose-dependently reduced by TBT ≥ 1 μM. The TBT-driven enzyme desensitization was reversed by DTE.Conclusions
The macrolides tested share uncompetitive inhibition mechanism by binding to a specific site in a common macrolide-binding region of FO. The oxidation of highly conserved thiols in the ATP synthase c-ring of FO weakens the interaction between the enzyme and the macrolides. The native macrolide-inhibited enzyme conformation can be restored by reducing crucial thiols oxidized by TBT.General significance
The findings, by elucidating the macrolide inhibitory mechanism on FO, indirectly cast light on the F1FO torque generation involving crucial amino acid residues and may address drug design and antimicrobial therapy. 相似文献13.
Shinjinee Sengupta Shakri BanerjeeSagar Lahiri Trina DuttaTarun K. Dhar Anil K. Ghosh 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
In Saccharomyces cerevisiae methylation at cysteine residue displayed enhanced activity of trehalose-6-phosphate synthase (TPS).Methods
The cysteine methyltransferase (CMT) responsible for methylating TPS was purified and characterized. The amino acid sequence of the enzyme protein was determined by a combination of N-terminal sequencing and MALDI-TOF/TOF analysis. The nucleotide sequence of the CMT gene was determined, isolated from S. cerevisiae and expressed in E. coli. Targeted disruption of the CMT gene by PCR based homologous recombination in S. cerevisiae was followed by metabolite characterization in the mutant.Results
The purified enzyme was observed to enhance the activity of TPS by a factor of 1.76. The 14 kDa enzyme was found to be cysteine specific. The optimum temperature and pH of enzyme activity was calculated as 30 °C and 7.0 respectively. The Km Vmax and Kcat against S-adenosyl-l-methionine (AdoMet) were 4.95 μM, 3.2 U/mg and 6.4 s− 1 respectively. Competitive inhibitor S-Adenosyl-l-homocysteine achieved a Ki as 10.9 μM against AdoMet. The protein sequence contained three putative AdoMet binding motifs. The purified recombinant CMT activity exhibited similar physicochemical characteristics with the native counterpart. The mutant, Mataα, cmt:: kanr exhibited almost 50% reduction in intracellular trehalose concentration.Conclusion
A novel cysteine methyltransferase is purified, which is responsible for enhanced levels of trehalose in S. cerevisiae.General significance
This is the first report about a cysteine methyltransferase which performs S methylation at cysteine residue regulating TPS activity by 50%, which resulted in an increase of the intercellular stress sugar, trehalose. 相似文献14.
Background
Receptor for advanced glycation end-product (RAGE) gene polymorphism 2245G/A is associated with diabetic retinopathy (DR). However, the mechanism on how it affects the disease development is still unclear.Aim
This study aims to investigate the relationship between 2245G/A RAGE gene polymorphism and selected pro-inflammatory, oxidative-glycation markers in DR patients.Methods
A total of 371 unrelated type 2 diabetic patients [200 with retinopathy, 171 without retinopathy (DNR)] and 235 healthy subjects were recruited. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism method followed by DNA sequencing. The nuclear and cytosolic extracts from peripheral blood mononuclear cells were used for nuclear factor kappa B (NF-κB) p65 and superoxide dismutase activity measurement respectively. Plasma was used for glutathione peroxidase activity, advanced oxidation protein product (AOPP), monocyte chemoattractant protein (MCP)-1, pentosidine and soluble RAGE (sRAGE) measurements.Results
DR patients with 2245GA genotype had significantly elevated levels of activated NF-κB p65, plasma MCP-1, AOPP and pentosidine but lower level of sRAGE when compared to DR patients with wild-type 2245GG.Conclusion
The RAGE gene polymorphism 2245G/A is associated with pro-inflammatory, oxidative-glycation markers and circulating sRAGE in DR patients. Patients with 2245GA RAGE genotype could aggravate DR possibly via NF-κB mediated inflammatory pathway. 相似文献15.
Mohd Hafeez Faridi Mehmet M. Altintas Camilo Gomez Juan Camilo Duque Roberto I. Vazquez-Padron Vineet Gupta 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
CD11b/CD18 is a key adhesion receptor that mediates leukocyte adhesion, migration and immune functions. We recently identified novel compounds, leukadherins, that allosterically enhance CD11b/CD18-dependent cell adhesion and reduce inflammation in vivo, suggesting integrin activation to be a novel mechanism of action for the development of anti-inflammatory therapeutics. Since a number of well-characterized anti-CD11b/CD18 activating antibodies are currently available, we wondered if such biological agonists could also become therapeutic leads following this mechanism of action.Methods
We compared the two types of agonists using in vitro cell adhesion and wound-healing assays and using animal model systems. We also studied effects of the two types of agonists on outside-in signaling in treated cells.Results
Both types of agonists similarly enhanced integrin-mediated cell adhesion and decreased cell migration. However, unlike leukadherins, the activating antibodies produced significant CD11b/CD18 macro clustering and induced phosphorylation of key proteins involved in outside-in signaling. Studies using conformation reporter antibodies showed that leukadherins did not induce global conformational changes in CD11b/CD18 explaining the reason behind their lack of ligand-mimetic outside-in signaling. In vivo, leukadherins reduced vascular injury in a dose-dependent fashion, but, surprisingly, the anti-CD11b activating antibody ED7 was ineffective.Conclusions
Our results suggest that small molecule allosteric agonists of CD11b/CD18 have clear advantages over the biologic activating antibodies and provide a mechanistic basis for the difference.General significance
CD11b/CD18 activation represents a novel strategy for reducing inflammatory injury. Our study establishes small molecule leukadherins as preferred agonists over activating antibodies for future development as novel anti-inflammatory therapeutics. 相似文献16.
Claudia F. Dick André L.A. Dos-Santos José R. Meyer-Fernandes 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
Inorganic phosphate (Pi) is an essential nutrient for all organisms. The route of Pi utilization begins with Pi transport across the plasma membrane.Scope of review
Here, we analyzed the gene sequences and compared the biochemical profiles, including kinetic and modulator parameters, of Pi transporters in unicellular eukaryotes. The objective of this review is to evaluate the recent findings regarding Pi uptake mechanisms in microorganisms, such as the fungi Neurospora crassa and Saccharomyces cerevisiae and the parasite protozoans Trypanosoma cruzi, Trypanosoma rangeli, Leishmania infantum and Plasmodium falciparum.Major conclusion
Pi uptake is the key step of Pi homeostasis and in the subsequent signaling event in eukaryotic microorganisms.General significance
Biochemical and structural studies are important for clarifying mechanisms of Pi homeostasis, as well as Pi sensor and downstream pathways, and raise possibilities for future studies in this field. 相似文献17.
Background
In the membrane-bound enzyme cytochrome c oxidase, electron transfer from cytochrome c to O2 is linked to proton uptake from solution to form H2O, resulting in a charge separation across the membrane. In addition, the reaction drives pumping of protons across the membrane.Methods
In this study we have measured voltage changes as a function of pH during reaction of the four-electron reduced cytochrome c oxidase from Rhodobacter sphaeroides with O2. These electrogenic events were measured across membranes containing purified enzyme reconstituted into lipid vesicles.Results
The results show that the pH dependence of voltage changes (primarily associated with proton transfer) during O2 reduction does not match that of the previously studied absorbance changes (primarily associated with electron transfer). Furthermore, the voltage changes decrease with increasing pH.Conclusions
The data indicate that cytochrome c oxidase does not pump protons at high pH (10.5) (or protons are taken from the “wrong” side of the membrane) and that at this pH the net proton-uptake stoichiometry is ∼ 1/2 of that at pH 8. Furthermore, the results provide a basis for interpretation of results from studies of mutant forms of the enzyme.General significance
These results provide new insights into the function of cytochrome c oxidase. 相似文献18.
19.
Hua Huang Pirkko Koelle Markus Fendler Angelika Schroettle Michael Czihal Ulrich Hoffmann Peter Jan Kuhlencordt 《PloS one》2014,9(12)
Introduction
Niacin reduces vascular oxidative stress and down regulates inducible nitric oxide synthase, an enzyme mediating proatherosclerotic effects in part by increasing oxidative stress. Here, we evaluate whether Niacin reverses the redox sensitive migratory arrest of macrophages in response to oxidised(ox) LDL uptake.Material and Methods
Migration of RAW264.7 cells, a murine macrophage cell line and bone marrow derived macrophages from wildtype and iNOS knockout mice was quantified using a modified Boyden chamber. Unstimulated cells or cells preincubated with oxLDL or non-oxidised (n)LDL were treated with Nicotinic acid or Nicotinamide. Nitric oxide, peroxynitrite and ROS production were assessed using electron paramagnetic resonance (ESR). Additionally, flow cytometry analysis of apoptosis, fokal adhesion kinase (FAK), phalloidin, CD36, F4/80 macrophage marker and iNOS gene expression (PCR) were assessed.Results
Migration of Nicotinic acid, Nicotinamide treated cells or unstimulated cells did not differ (P>0.05). oxLDL treatment significantly reduced migration vs. unstimulated cells (p<0.05). In contrast, migratory arrest in response to oxLDL treatment was reversed by co-incubation with Nicotinic acid and Nicotinamide. The oxLDL-induced peroxynitrite formation in RAW264.7 cells was abolished by Niacin and glutathion (GSH) oxidation was significantly reduced. However, nitric oxide (NO)- and reactive oxygen species (ROS) production induced by oxLDL were not affected by Niacin treatment of RAW264.7 cells. In addition, Nicotinic acid and Nicotinamide reduced actin polymerization, a marker for migratory arrest.Discussion
Our data shows that oxLDL induced inhibition of macrophage migration in vitro can be reversed by Niacin. Furthermore, Niacin reduces peroxynitite formation and improves antioxidant GSH. 相似文献20.
Roland Baur Wolfgang Schuehly Erwin Sigel 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014