共查询到20条相似文献,搜索用时 31 毫秒
1.
Bennett L. Ibey Andrei G. Pakhomov Betsy W. Gregory Vera A. Khorokhorina Caleb C. Roth Mikhail A. Rassokhin Joshua A. Bernhard Gerald J. Wilmink Olga N. Pakhomova 《Biochimica et Biophysica Acta (BBA)/General Subjects》2010
Background
Nanosecond electric pulses (EP) disrupt cell membrane and organelles and cause cell death in a manner different from the conventional irreversible electroporation. We explored the cytotoxic effect of 10-ns EP (quantitation, mechanisms, efficiency, and specificity) in comparison with 300-ns, 1.8- and 9-μs EP.Methods
Effects in Jurkat and U937 cells were characterized by survival assays, DNA electrophoresis and flow cytometry.Results
10-ns EP caused apoptotic or necrotic death within 2–20 h. Survival (S, %) followed the absorbed dose (D, J/g) as: S = αD(−K), where coefficients K and α determined the slope and the “shoulder” of the survival curve. K was similar in all groups, whereas α was cell type- and pulse duration-dependent. Long pulses caused immediate propidium uptake and phosphatidylserine (PS) externalization, whereas 10-ns pulses caused PS externalization only.Conclusions
1.8- and 9-μs EP cause cell death efficiently and indiscriminately (LD50 1–3 J/g in both cell lines); 10-ns EP are less efficient, but very selective (LD50 50–80 J/g for Jurkat and 400–500 J/g for U937); 300-ns EP show intermediate effects. Shorter EP open propidium-impermeable, small membrane pores (”nanopores”), triggering different cell death mechanisms.General significance
Nanosecond EP can selectively target certain cells in medical applications like tumor ablation. 相似文献2.
Hideaki Tagashira Chen Zhang Ying-mei Lu Hideyuki Hasegawa Hiroshi Kanai Feng Han Kohji Fukunaga 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
We previously reported that the σ1-receptor (σ1R) is down-regulated following cardiac hypertrophy and dysfunction in transverse aortic constriction (TAC) mice. Here we address how σ1R stimulation with the selective σ1R agonist SA4503 restores hypertrophy-induced cardiac dysfunction through σ1R localized in the sarcoplasmic reticulum (SR).Methods
We first confirmed anti-hypertrophic effects of SA4503 (0.1–1 μM) in cultured cardiomyocytes exposed to angiotensin II (Ang II). Then, to confirm the ameliorative effects of σ1R stimulation in vivo, we administered SA4503 (1.0 mg/kg) and the σ1R antagonist NE-100 (1.0 mg/kg) orally to TAC mice for 4 weeks (once daily).Results
σ1R stimulation with SA4503 significantly inhibited Ang II-induced cardiomyocyte hypertrophy. Ang II exposure for 72 h impaired phenylephrine (PE)-induced Ca2 + mobilization from the SR into both the cytosol and mitochondria. Treatment of cardiomyocytes with SA4503 largely restored PE-induced Ca2 + mobilization into mitochondria. Exposure of cardiomyocytes to Ang II for 72 h decreased basal ATP content and PE-induced ATP production concomitant with reduced mitochondrial size, while SA4503 treatment completely restored ATP production and mitochondrial size. Pretreatment with NE-100 or siRNA abolished these effects. Chronic SA4503 administration also significantly attenuated myocardial hypertrophy and restored ATP production in TAC mice. SA4503 administration also decreased hypertrophy-induced impairments in LV contractile function.Conclusions
σ1R stimulation with the specific agonist SA4503 ameliorates cardiac hypertrophy and dysfunction by restoring both mitochondrial Ca2 + mobilization and ATP production via σ1R stimulation.General significance
Our observations suggest that σ1R stimulation represents a new therapeutic strategy to rescue the heart from hypertrophic dysfunction. 相似文献3.
Stine Krog Frandsen Hanne Gissel Pernille Hojman Jens Eriksen Julie Gehl 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
Electroporation with calcium (calcium electroporation) can induce ATP depletion-associated cellular death. In the clinical setting, the cytotoxic drug bleomycin is currently used with electroporation (electrochemotherapy) for palliative treatment of tumors. Calcium electroporation offers several advantages over standard treatment options: calcium is inexpensive and may readily be applied without special precautions, as is the case with cytostatic drugs. Therefore, details on the use of calcium electroporation are essential for carrying out clinical trials comparing calcium electroporation and electrochemotherapy.Methods
The effects of calcium electroporation and bleomycin electroporation (alone or in combination) were compared in three different cell lines (DC-3F, transformed Chinese hamster lung fibroblast; K-562, human leukemia; and murine Lewis Lung Carcinoma). Furthermore, the effects of electrical pulsing parameters and calcium compound on treatment efficacy were determined.Results
Electroporation with either calcium or bleomycin significantly reduced cell survival (p < 0.0001), without evidence of a synergistic effect. Cellular death following calcium or bleomycin treatment occurred at similar applied voltages, suggesting that similar parameters should be applied. At equimolar concentrations, calcium chloride and calcium glubionate resulted in comparable decreases in cell viability.Conclusions
Calcium electroporation and bleomycin electroporation significantly reduce cell survival at similar applied voltage parameters. The effect of calcium electroporation is independent of calcium compound.General significance
This study strongly supports the use of calcium electroporation as a potential cancer therapy and the results may aid in future clinical trials. 相似文献4.
Antonella Santoro Anna Rita CappelloMarianna Madeo Emanuela MartelloDomenico Iacopetta Vincenza Dolce 《Biochimica et Biophysica Acta (BBA)/General Subjects》2011
Background
Fosfomycin is widely used to treat urinary tract and pediatric gastrointestinal infections of bacteria. It is supposed that this antibiotic enters cells via two transport systems, including the bacterial Glycerol-3-phosphate Transporter (GlpT). Impaired function of GlpT is one mechanism for fosfomycin resistance.Methods
The interaction of fosfomycin with the recombinant and purified GlpT of Escherichia coli reconstituted in liposomes has been studied. IC50 and the half-saturation constant of the transporter for external fosfomycin (Ki) were determined by transport assay of [14C]glycerol-3-phosphate catalyzed by recombinant GlpT. Efficacy of fosfomycin on growth rates of GlpT defective bacteria strains transformed with recombinant GlpT was measured.Results
Fosfomycin, externally added to the proteoliposomes, poorly inhibited the glycerol-3-phosphate/glycerol-3-phosphate antiport catalyzed by the reconstituted transporter with an IC50 of 6.4 mM. A kinetic analysis revealed that the inhibition was completely competitive, that is, fosfomycin interacted with the substrate-binding site and the Ki measured was 1.65 mM. Transport assays performed with proteoliposomes containing internal fosfomycin indicate that it was not very well transported by GlpT. Complementation study, performed with GlpT defective bacteria strains, indicated that the fosfomycin resistance, beside deficiency in antibiotic transporter, could be due to other gene defects.Conclusions
The poor transport observed in a reconstituted system together with the high value of Ki and the results of complementation study well explain the usual high dosage of this drug for the treatment of the urinary tract infections.General significance
This is the first report regarding functional analysis of interaction between fosfomycin and GlpT. 相似文献5.
Rafael Gregorio Mendes Britta Koch Alicja Bachmatiuk Ahmed Aboud El-Gendy Yulia Krupskaya Armin Springer Rüdiger Klingeler Oliver Schmidt Bernd Büchner Samuel Sanchez Mark Hermann Rümmeli 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
Iron oxide nanoparticles hold great promise for future biomedical applications. To this end numerous studies on iron oxide nanoparticles have been conducted. One aspect these studies reveal is that nanoparticle size and shape can trigger different cellular responses through endocytic pathways, cell viability and early apoptosis. However, systematic studies investigating the size dependence of iron oxide nanoparticles with highly defined diameters across multiple cells lines are not available yet.Methods
Iron oxide nanoparticles with well-defined size distributions were prepared. All samples were thoroughly characterized and the cytotoxicity for four standard cell lines (HeLa Kyoto, human osteosarcoma (U2OS), mouse fibroblasts (NIH 3T3) and mouse macrophages (J7442)) where investigated.Results
Our findings show that small differences in size distribution (ca. 10 nm) of iron oxide nanoparticles do not influence cytotoxicity, while uptake is size dependent. Cytotoxicity is dose-dependent. Broad distributions of nanoparticles are more easily internalized as compared to the narrow distributions for two of the cell lines tested (HeLa Kyoto and mouse macrophages (J7442)).Conclusion
The data indicate that it is not feasible to probe changes in cytotoxicity within a small size range (10 nm). However, TEM investigations of the nanoparticles indicate that cellular uptake is size dependent.General significance
The present work compares narrow and broad distributions for various samples of carbon-coated iron oxide nanoparticles. The data highlights that cells differentiate between nanoparticle sizes as indicated by differences in cellular uptake. This information provides valuable knowledge to better understand the interaction of nanoparticles and cells. 相似文献6.
Background
The deposition of aggregated β-amyloid peptide senile plaques and the accumulation of arginine within the astrocytes in the brain of an Alzheimer's patient are classic observations in the neuropathology of the disease. It would be logical, in the aetiology and pathogenesis, to investigate arginine-metabolising enzymes and their intimate association with amyloid peptides.Methods
Neuronal nitric oxide synthase (nNOS) was isolated, purified and shown, through fluorescence quenching spectroscopy and fluorescence resonance energy transfer (FRET), to interact with structural fragments of Aβ1–40 and be catalytic towards amyloid fibril formation.Results
Only one binding site on the enzyme was available for binding. Two amyloid peptide fragments of Aβ1–40 (Aβ17–28 and Aβ25–35) had Stern–Volmer values (KSV) of 0.111 μM−1 and 0.135 μM−1 indicating tight binding affinity to nNOS and easier accessibility to fluor molecules during binding. The polarity of this active site precludes binding of the predominantly hydrophobic amyloid peptide fragments contained within Aβ17–28 and within two glycine zipper motifs [G-X-X-X-G-X-X-X-G] [Aβ29–37] and bind to the enzyme at a site remote to the active region.Conclusions
The interaction and binding of Aβ17–28 and Aβ25–35 to nNOS causes the movement of two critical tryptophan residues of 0.77 nm and 0.57 nm respectively towards the surface of the enzyme.General significance
The binding of Aβ-peptide fragments with nNOS has been studied by spectrofluorimetry. The information and data presented should contribute towards understanding the mechanism for deposition of aggregated Aβ-peptides and fibrillogenesis in senile plaques in an AD brain. 相似文献7.
Kamaldeep Gill Abhay K. Singh Vaishali Kapoor Lokesh Nigam Rahul Kumar Prasida Holla Satya N. Das Savita Yadav Naidu Subbarao Bidhu K. Mohanti Sharmistha Dey 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
The p38α MAP kinase pathway is involved in inflammation, cell differentiation, growth, apoptosis and production of pro-inflammatory cytokines TNF-α and IL-1β. The overproduction of these cytokines plays an important role in cancer. The aim of this work was to design a peptide inhibitor on the basis of structural information of the active site of p38α.Methods
A tetrapeptide, VWCS as p38α inhibitor was designed on the basis of structural information of the ATP binding site by molecular modeling. The inhibition study of peptide with p38α was performed by ELISA, binding study by Surface Plasmon Resonance and anti-proliferative assays by MTT and flow cytometry.Results
The percentage inhibition of designed VWCS against pure p38α protein and serum of HNSCC patients was 70.30 and 71.5%, respectively. The biochemical assay demonstrated the KD and IC50 of the selective peptide as 7.22 × 10− 9 M and 20.08 nM, respectively. The VWCS as inhibitor significantly reduced viability of oral cancer KB cell line with an IC50 value of 10 μM and induced apoptosis by activating Caspase 3 and 7.Conclusions
VWCS efficiently interacted at the ATP binding pocket of p38α with high potency and can be used as a potent inhibitor in case of HNSCC.General significance
VWCS can act as an anticancer agent as it potentially inhibits the cell growth and induces apoptosis in oral cancer cell-line in a dose as well as time dependent manner. Hence, p38α MAP kinase inhibitor can be a potential therapeutic agent for human oral cancer. 相似文献8.
9.
Mauro Gaya Victoria Repetto Judith Toneatto Claudia Anesini Graciela Piwien-Pilipuk Silvia Moreno 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
Obesity is a serious health problem all over the world, and inhibition of adipogenesis constitutes one of the therapeutic strategies for its treatment. Carnosic acid (CA), the main bioactive compound of Rosmarinus officinalis extract, inhibits 3T3-L1 preadipocytes differentiation. However, very little is known about the molecular mechanism responsible for its antiadipogenic effect.Methods
We evaluated the effect of CA on the differentiation of 3T3-L1 preadipocytes analyzing the process of mitotic clonal expansion, the level of adipogenic markers, and the subcellular distribution of C/EBPβ.Results
CA treatment only during the first day of 3T3-L1 differentiation process was enough to inhibit adipogenesis. This inhibition was accompanied by a blockade of mitotic clonal expansion. CA did not interfere with C/EBPβ and C/EBPδ mRNA levels but blocked PPARγ, and FABP4 expression. C/EBPβ has different forms known as LIP and LAP. CA induced an increase in the level of LIP within 24 h of differentiation, leading to an increment in LIP/LAP ratio. Importantly, overexpression of LAP restored the capacity of 3T3-L1 preadipocytes to differentiate in the presence of CA. Finally, CA promoted subnuclear de-localization of C/EBPβ.Conclusions
CA exerts its anti-adipogenic effect in a multifactorial manner by interfering mitotic clonal expansion, altering the ratio of the different C/EBPβ forms, inducing the loss of C/EBPβ proper subnuclear distribution, and blocking the expression of C/EBPα and PPARγ.General significance
Understanding the molecular mechanism by which CA blocks adipogenesis is relevant because CA could be new a food additive beneficial for the prevention and/or treatment of obesity. 相似文献10.
Background
Argonaute (Ago) proteins are essential for the biogenesis and function of ~ 20–30 nucleotide long RNAs such as microRNAs (miRNAs). Ago expression increases or decreases under various physiological conditions, although the functional consequences are unknown. In addition, while reduced global miRNA production was shown to enhance cellular transformation and tumorigenesis, how Ago proteins contribute to human diseases has not been reported.Method
Ago2, an essential Ago isoform in mammals, was stably expressed in 293 T, the human embryonic kidney cell line, and H1299, the human lung adenocarcinoma cell line. miRNA and mRNA expression was investigated by quantitative PCR and microarray profiling. Cell proliferation and migration was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and scratch assay in the cell cultures, respectively. How Ago2 affected cell growth in vivo was determined by H1299 xenograft tumor growth in mice. Changes in Ago2 expression in human lung cancer samples were investigated by quantitative PCR and immunohistochemistry.Results
Stable Ago2 overexpression elicited specific changes in miRNA and mRNA expression in both 293 T and H1299 cells. It also inhibited cell proliferation and migration in cell cultures as well as xenograft tumor growth in nude mice. Ago2 expression was lower in human lung adenocarcinomas than in the paired, non-cancerous tissues.General significance
We concluded that changes in Ago2 expression might have significant physiological and pathological consequences in vivo. 相似文献11.
A. Anitha N. DeepaK.P. Chennazhi Vinoth-Kumar LakshmananR. Jayakumar 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
Evaluation of the combinatorial anticancer effects of curcumin/5-fluorouracil loaded thiolated chitosan nanoparticles (CRC-TCS-NPs/5-FU-TCS-NPs) on colon cancer cells and the analysis of pharmacokinetics and biodistribution of CRC-TCS-NPs/5-FU-TCS-NPs in a mouse model.Methods
CRC-TCS-NPs/5-FU-TCS-NPs were developed by ionic cross-linking. The in vitro combinatorial anticancer effect of the nanomedicine was proven by different assays. Further the pharmacokinetics and biodistribution analyses were performed in Swiss Albino mouse using HPLC.Results
The 5-FU-TCS-NPs (size: 150 ± 40 nm, zeta potential: + 48.2 ± 5 mV) and CRC-TCS-NPs (size: 150 ± 20 nm, zeta potential: + 35.7 ± 3 mV) were proven to be compatible with blood. The in vitro drug release studies at pH 4.5 and 7.4 showed a sustained release profile over a period of 4 days, where both the systems exhibited a higher release in acidic pH. The in vitro combinatorial anticancer effects in colon cancer (HT29) cells using MTT, live/dead, mitochondrial membrane potential and cell cycle analysis measurements confirmed the enhanced anticancer effects (2.5 to 3 fold). The pharmacokinetic studies confirmed the improved plasma concentrations of 5-FU and CRC up to 72 h, unlike bare CRC and 5-FU.Conclusions
To conclude, the combination of 5-FU-TCS-NPs and CRC-TCS-NPs showed enhanced anticancer effects on colon cancer cells in vitro and improved the bioavailability of the drugs in vivo.General significance
The enhanced anticancer effects of combinatorial nanomedicine are advantageous in terms of reduction in the dosage of 5-FU, thereby improving the chemotherapeutic efficacy and patient compliance of colorectal cancer cases. 相似文献12.
13.
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14.
Jinggong Liu Weilin Liu Hu Ge Jinbo Gao Qingqing He Lijuan Su Jun Xu Lian-quan Gu Zhi-shu Huang Ding Li 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
Farnesyl pyrophosphate synthase (FPPS) is a key regulatory enzyme in the biosynthesis of cholesterol and in the post-translational modification of signaling proteins. It has been reported that non-bisphosphonate FPPS inhibitors targeting its allosteric binding pocket are potentially important for the development of promising anti-cancer drugs.Methods
The following methods were used: organic syntheses of non-bisphosphonate quinoline derivatives, enzyme inhibition studies, fluorescence titration assays, synergistic effect studies of quinoline derivatives with zoledronate, ITC studies for the binding of FPPS with quinoline derivatives, NMR-based HAP binding assays, molecular modeling studies, fluorescence imaging assay and MTT assays.Results
We report our syntheses of a series of quinoline derivatives as new FPPS inhibitors possibly targeting the allosteric site of the enzyme. Compound 6b showed potent inhibition to FPPS without significant hydroxyapatite binding affinity. The compound showed synergistic inhibitory effect with active-site inhibitor zoledronate. ITC experiment confirmed the good binding effect of compound 6b to FPPS, and further indicated the binding ratio of 1:1. Molecular modeling studies showed that 6b could possibly bind to the allosteric binding pocket of the enzyme. The fluorescence microscopy indicated that these compounds could get into cancer cells.Conclusions
Our results showed that quinoline derivative 6b could become a new lead compound for further optimization for cancer treatment.General significance
The traditional FPPS active-site inhibitors bisphosphonates show poor membrane permeability to tumor cells, due to their strong polarity. The development of new non-bisphosphonate FPPS inhibitors with good cell membrane permeability is potentially important. 相似文献15.
Andrew W. Farrell Safina GadeockAleta Pupovac Bin WangIman Jalilian Marie RansonRonald Sluyter 《Biochimica et Biophysica Acta (BBA)/General Subjects》2010
Background
The extracellular ATP-gated cation channel, P2X7 receptor, has an emerging role in neoplasia, however progress in the field is limited by a lack of malignant cell lines expressing this receptor.Methods
Immunofluorescence labelling and a fixed-time ATP-induced ethidium+ uptake assay were used to screen a panel of human malignant cell lines for the presence of functional P2X7. The presence of P2X7 was confirmed by RT-PCR, immunoblotting and pharmacological approaches. ATP-induced cell death was measured by colourimetric tetrazolium-based and cytofluorometric assays. ATP-induced CD23 shedding was measured by immunofluorescence labelling and ELISA.Results
RPMI 8226 multiple myeloma cells expressed P2X7 mRNA and protein, as well as P2X1, P2X4 and P2X5 mRNA. ATP induced ethidium+ uptake into these cells with an EC50 of ~ 116 μM, and this uptake was reduced in the presence of extracellular Ca2+ and Mg2+. The P2X7 agonist 2'- and 3'-0(4-benzoylbenzoyl) ATP, but not UTP, induced ethidium+ uptake. ATP-induced ethidium+ uptake was impaired by the P2X7 antagonists, KN-62 and A-438079. ATP induced death and CD23 shedding in RPMI 8226 cells, and both processes were impaired by P2X7 antagonists. The metalloprotease antagonists, BB-94 and GM6001, impaired ATP-induced CD23 shedding but not ethidium+ uptake.Conclusions
P2X7 receptor activation induces cell death and CD23 shedding in RPMI 8226 cells.General significance
RPMI 8226 cells may be useful to study the role of P2X7 in multiple myeloma and B-lymphocytes. 相似文献16.
Lucie Trnková Daniela Ricci Caterina Grillo Gianni Colotti Fabio Altieri 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
Green tea is a rich source of polyphenols, mainly catechins (flavanols), which significantly contribute to the beneficial health effects of green tea in the prevention and treatment of various diseases. In this study the effects of four green tea catechins on protein ERp57, also known as protein disulfide isomerase isoform A3 (PDIA3), have been investigated in an in vitro model.Methods
The interaction of catechins with ERp57 was explored by fluorescence quenching and surface plasmon resonance techniques and their effect on ERp57 activities was investigated.Results
A higher affinity was observed for galloylated cathechins, which bind close to the thioredoxin-like redox-sensitive active sites of the protein, with a preference for the oxidized form. The effects of these catechins on ERp57 properties were also investigated and a moderate inhibition of the reductase activity of ERp57 was observed as well as a strong inhibition of ERp57 DNA binding activity.Conclusions
Considering the high affinity of galloylated catechins for ERp57 and their capability to inhibit ERp57 binding to other macromolecular ligands, some effects of catechins interaction with this protein on eukaryotic cells may be expected.General significance
This study provides information to better understand the molecular mechanisms underlying the biological activities of catechins and to design new polyphenol-based ERp57-specific inhibitors. 相似文献17.
Peter Schönfeld Nicol Kruska Georg Reiser 《Biochimica et Biophysica Acta (BBA)/General Subjects》2009,1790(12):1698-1704
Background
Hydroxy-1-aryl-isochromans (HAIC) are newly emerging natural polyphenolic antioxidants, enriched in extravirgin olive oil, whose antioxidative potency was only scarcely characterized using cell-free systems and cells.Methods
We characterized the activity of HAIC to inactivate reactive oxygen species (ROS) generated by the xanthine/xanthine oxidase system, mitochondria (rat brain) and neural cells. ROS levels were estimated using ROS-sensitive probes, such as Amplex Red, MitoSOXRED.Results
HAIC (with 2, 3 or 4 hydroxyl substituents) effectively scavenge ROS released from mitochondria. EC50 values estimated with mitochondria and submitochondrial particles were around 20 μM. Moreover, in PC12 and cultured neural primary cells, HAIC buffered cytosolic ROS. Although HAIC permeate biological membranes, HAIC fail to buffer matrix ROS in isolated mitochondria. We show that hydrogen peroxide was effectively abolished by HAIC, whereas the production of superoxide was not affected.Conclusion
HAIC exert high antioxidative activity to reduce hydrogen peroxide. The antioxidative activity of HAIC is comparable with that of the stilbene-like, polyphenolic resveratrol, but much higher than that of trolox, N-acetylcysteine or melatonin.General significance
Unlike resveratrol, HAIC do not impair mitochondrial ATP synthesis or Ca2+ retention by mitochondria. Thus, HAIC have the decisive advantage to be potent antioxidants with no detrimental side effects on mitochondrial functions. 相似文献18.
19.
Alexandra A. Kuznetsova Nikita A. Kuznetsov Alexander A. Ishchenko Murat K. Saparbaev Olga S. Fedorova 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
DNA glycosylases remove the modified, damaged or mismatched bases from the DNA by hydrolyzing the N-glycosidic bonds. Some enzymes can further catalyze the incision of a resulting abasic (apurinic/apyrimidinic, AP) site through β- or β,δ-elimination mechanisms. In most cases, the incision reaction of the AP-site is catalyzed by special enzymes called AP-endonucleases.Methods
Here, we report the kinetic analysis of the mechanisms of modified DNA transfer from some DNA glycosylases to the AP endonuclease, APE1. The modified DNA contained the tetrahydrofurane residue (F), the analogue of the AP-site. DNA glycosylases AAG, OGG1, NEIL1, MBD4cat and UNG from different structural superfamilies were used.Results
We found that all DNA glycosylases may utilise direct protein–protein interactions in the transient ternary complex for the transfer of the AP-containing DNA strand to APE1.Conclusions
We hypothesize a fast “flip-flop” exchange mechanism of damaged and undamaged DNA strands within this complex for monofunctional DNA glycosylases like MBD4cat, AAG and UNG. Bifunctional DNA glycosylase NEIL1 creates tightly specific complex with DNA containing F-site thereby efficiently competing with APE1. Whereas APE1 fast displaces other bifunctional DNA glycosylase OGG1 on F-site thereby induces its shifts to undamaged DNA regions.General significance
Kinetic analysis of the transfer of DNA between human DNA glycosylases and APE1 allows us to elucidate the critical step in the base excision repair pathway. 相似文献20.
Divya Pathania Mario Sechi Michele Palomba Vanna Sanna Francesco Berrettini Angela Sias Laleh Taheri Nouri Neamati 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014