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1.
2.
Human tumor necrosis factor α (hTNFα), a pleiotropic cytokine with activities ranging from host defense mechanisms in infection and injury to severe toxicity in septic shock or other related diseases, is a promising target for drug screening. Using the SELEX (systematic evolution of ligands by exponential enrichment) process, we isolated oligonucleotide ligands (aptamers) with high affinities for hTNFα.Aptamers were selected from a starting pool of 40 randomized sequences composed of about 10^15 RNA molecules. Representative aptamers were truncated to the minimal length with high affinity for hTNFα and were further modified by replacement of 2′-OH with 2′-F and 2′-NH2 at all ribopurine positions. These modified RNA aptamers were resistant to nuclease. The specificity of these aptamers for hTNFα was confirmed, and their activity to inhibit the cytotoxicity of hTNFα on mouse L929 cells was determined. Results demonstrated that four 2′-NH2-modified aptamers bound to hTNFα with high affinity and blocked the binding of hTNFα to its receptor, thus protecting the L929 cells from the cytotoxicity of hTNFα. Oligonucleotide aptamers described here are potential therapeutics and diagnostics for hTNFα-related diseases.  相似文献   

3.
Human tumor necrosis factor a (hTNFa), a pleiotropic cytokine with activities ranging from host defense mechanisms in infection and injury to severe toxicity in septic shock or other related diseases, is a promising target for drug screening. Using the SELEX (systematic evolution of ligands by exponential enrichment) process, we isolated oligonucleotide ligands (aptamers) with high affinities for hTNFa. Aptamers were selected from a starting pool of 40 randomized sequences composed of about 1015 RNA molecules. Representative aptamers were truncated to the minimal length with high affinity for hTNFa and were further modified by replacement of 2'-OH with 2'-F and 2'-NH2 at all ribopurine positions. These modified RNA aptamers were resistant to nuclease. The specificity of these aptamers for hTNFa was confirmed, and their activity to inhibit the cytotoxicity of hTNFa on mouse L929 cells was determined. Results demonstrated that four 2'-NH2-modified aptamers bound to hTNFa with high affinity and blocked the  相似文献   

4.
PPARgamma ligands inhibit growth and induce apoptosis of various cancer cells. 4-Hydroxynonenal (HNE), a product of lipid peroxidation, inhibits proliferation and induces differentiation or apoptosis in neoplastic cells. The aim of this work was to investigate the effects of PPARgamma ligands (rosiglitazone and 15-deoxy-prostaglandin J2 (15d-PGJ2)) and HNE, alone or in association, on proliferation, apoptosis, differentiation, and growth-related and apoptosis-related gene expression in colon cancer cells (CaCo-2 cells). PPARgamma ligands inhibited cell proliferation (IC50 was 37.47+/-6.6 microM, for 15d-PGJ2, and 170.34+/-20 microM for rosiglitazone). HNE (1 microM) inhibited cell growth by 70%. Apoptosis was induced by 15d-PGJ2 and HNE and, to a minor extent, rosiglitazone. Differentiation was induced by rosiglitazone and by 15d-PGJ2, but not by HNE. PPARgamma ligands inhibited c-myc expression. HNE induced a transitory increase in c-myc expression and a subsequent down-regulation. HNE induced p21 expression, whereas PPARgamma ligands did not. Expression of the bax gene was increased by HNE and 15d-PGJ2, but not by rosiglitazone. No synergism or antagonism was found between HNE and PPARgamma ligands. Both apoptosis and differentiation induction may be responsible for the inhibition of proliferation by PPARgamma ligands; apoptosis and c-myc and p21 expression seem to be involved in the inhibition of proliferation by HNE.  相似文献   

5.
Thermodynamics of 2'-ribose substitutions in UUCG tetraloops   总被引:1,自引:0,他引:1       下载免费PDF全文
The ribose 2'-hydroxyl group confers upon RNA many unique molecular properties. To better appreciate its contribution to structure and stability and to monitor how substitutions of the 2' hydroxyl can alter an RNA molecule, each loop pyrimidine ribonucleotide in the UUCG tetraloop was substituted with a nucleotide containing either a fluorine (2'-F), hydrogen (2'-H), amino (2'-NH2), or methoxy (2'-OCH3) group, in the context of both the C:G and G:C loop-closing base pair. The thermodynamic parameters of these tetraloop variants have been determined and NMR experiments used to monitor the structural changes resulting from the substitutions. The modified riboses are better tolerated in the G[UUCG]C tetraloop, which may be due to its increased loop flexibility relative to the C[UUCG]G loop. Even for these simple substitutions, the free-energy change reflects a complex interplay of hydrogen bonding, solvation effects, and intrinsic pucker preferences of the nucleotides.  相似文献   

6.
An in vitro selection was designed to identify RNA-cleaving ribozymes predisposed for function as a drug. The selection scheme required the catalyst to be trans-acting with phosphodiesterase activity targeting a fragment of the Kras mRNA under simulated physiological conditions. To increase stabilization against nucleases and to offer the potential for improved functionality, modified sequence space was sampled by transcribing with the following NTPs: 2'-F-ATP, 2'-F-UTP, or 2'-F-5-[(N-imidazole-4-acetyl) propylamine]-UTP, 2'-NH2-CTP, and GTP. Active motifs were identified and assessed for their modified NMP and divalent metal dependence. The minimization of the ribozyme's size and the ability to substitute 2'-OMe for 2'-F and 2'-NH2 moieties yielded the motif from these selections most suited for both nuclease stability and therapeutic development. This motif requires only two 2'-NH2-Cs and functions as a 36-mer. Its substrate sequence requirements were determined to be 5'-Y-G-H-3'. Its half-life in human serum is >100 h. In physiologically relevant magnesium concentrations [approximately 1 mM] its kcat = 0.07 min(-1), Km = 70 nM. This report presents a novel nuclease stable ribozyme, designated Zinzyme, possessing optimal activity in simulated physiological conditions and ready for testing in a therapeutic setting.  相似文献   

7.
应用核酸适配子检测细胞因子的新方法—ELONA法   总被引:2,自引:0,他引:2  
以人肿瘤坏死因子(Human tumor necrosis factor,hTNF—α)特异性的核酸适配子为检测分子建立了酶联寡聚核苷酸吸附试验(Enzyme—linked Oligonucleotide assay,ELONA)方法,用于hTNF—α的检测。通过SELEX(Systematic Evolution of Ligands by Exponential Enrichment)方法从随机RNA库中筛选到与hTNF—α特异结合的RNA适配子。根据其序列,用体外转录方法合成生物素标记的RNA适配子,并对其进行了氨基修饰以增加其稳定性。以hTNF—α的单克隆抗体为捕获分子,生物素标记的hTNF—α特异性RNA适配子为检测分子建立了ELONA方法,并对这种检测方法的灵敏度、精密度和准确度等进行了分析。同时用ELONA和ELISA方法检测了正常人血清中的hTNF—α水平,并对检测结果进行比较。结果显示,ELONA方法的灵敏度为100pg/mL,具有较好的精密度和准确度。ELONA法的检测结果与ELISA法检测结果基本一致。该方法适用于血清、细胞培养上清等多种生物标本中各种细胞因子及其它蛋白的检测。  相似文献   

8.
目的:以人中性粒细胞弹性蛋白酶(HNE)为诱导因素,研究建立黏蛋白(MUC)5AC和5B高表达的细胞模型,同时对黏蛋白高表达机制进行初步研究。方法:培养人肺腺癌细胞A549,以HNE为刺激因素,EGFR中和抗体、表皮细胞生长因子受体(EGFR)磷酸化阻断剂AG1478为干预因素,分组培养。采用四甲基偶氮唑盐光吸收法(MTT法)检测HNE对细胞活性的影响;逆转录-聚合酶链反应(RT-PCR)检测MUC5AC mRNA、MUC5B mRNA的变化;酶联免疫吸附测定法(ELISA)定量分析MUC5AC和MUC5B蛋白含量的差异;细胞免疫化学以及激光共聚焦技术进一步直观观察MUC5AC、MUC5B、p-EGFR蛋白表达的变化。结果:HNE对A549细胞活力的影响呈剂量依赖性;HNE刺激组的MUC5AC、MUC5B基因转录和蛋白表达水平均明显高于对照组,差异有统计学意义(均P<0.01);HNE刺激组p-EGFR蛋白表达显著增多,EGFR中和抗体、AG1478能显著降低HNE诱导的MUC5AC高表达,但对MUC5B高表达无干预作用。结论:人肺腺癌细胞A549同时表达MUC5AC和MUC5B,HNE能有效刺激A549细胞高表达MUC5AC和MUC5B,黏蛋白高表达细胞模型的建立为研究气道粘液高分泌疾病提供了实验基础。HNE通过激活EGFR信号转导通路诱导MUC5AC的高表达,但MUC5B高表达机制与之不同,有待进一步研究。  相似文献   

9.
Fatty acid binding proteins (FABP) have been characterized as facilitating the intracellular solubilization and transport of long‐chain fatty acyl carboxylates via noncovalent interactions. More recent work has shown that the adipocyte FABP is also covalently modified in vivo on Cys117 with 4‐hydroxy‐2‐nonenal (4‐HNE), a bioactive aldehyde linked to oxidative stress and inflammation. To evaluate 4‐HNE binding and modification, the crystal structures of adipocyte FABP covalently and noncovalently bound to 4‐HNE have been solved to 1.9 Å and 2.3 Å resolution, respectively. While the 4‐HNE in the noncovalently modified protein is coordinated similarly to a carboxylate of a fatty acid, the covalent form show a novel coordination through a water molecule at the polar end of the lipid. Other defining features between the two structures with 4‐HNE and previously solved structures of the protein include a peptide flip between residues Ala36 and Lys37 and the rotation of the side chain of Phe57 into its closed conformation. Representing the first structure of an endogenous target protein covalently modified by 4‐HNE, these results define a new class of in vivo ligands for FABPs and extend their physiological substrates to include bioactive aldehydes.  相似文献   

10.
A T7 RNA polymerase in which Tyr639 is mutated to Phe readily utilizes 2'-deoxy, 2'-NH2 and 2'-F NTPs as substrates and has been widely used to synthesize modified RNAs for a variety of applications. This mutant does not readily utilize NTPs with bulkier 2'-substituents, nor does it facilitate incorporation of NTPs with modifications at other positions. Introduction of a second mutation (H784A) into the Y639F background markedly enhances utilization of NTPs with bulky 2'-substituents (2'-OMe and 2'-N3), and may also enhance use of NTPs with modifications at other than the 2'-position. The Y639F/H784A double mutant may therefore be exceptionally useful for incorporation of a variety of non-canonical NMPs into RNA.  相似文献   

11.
Peroxisome proliferator-activated receptors play an important role in the differentiation of different cell lines. In this study we demonstrate that PPAR-alpha ligands (clofibrate and ciprofibrate) and PPAR-gamma ligands (troglitazone and 15d-prostaglandin J2) inhibit growth and induce monocytic differentiation in HL-60 cells, whereas only PPAR-gamma ligands inhibit growth of U937 cells. Differentiation was demonstrated by the analysis of surface antigen expression CD11b and CD14, and by the characteristic morphological changes. PPAR-gamma ligands are more effective than PPAR-alpha ligands in the inhibition of cell growth and in the induction of differentiation. The physiological product of lipid peroxidation, 4-hydroxynonenal (HNE), which alone induces granulocytic-like differentiation of HL-60 cells, potentiates the monocytic differentiation induced by ciprofibrate, troglitazone, and 15d-prostaglandin J2. The same HNE treatment significantly inhibits U937 cell growth and potentiates the inhibition of cell growth in PPAR-gamma ligand-treated cells. However, HNE does not induce a significant number of CD14-positive U937 cells. HNE causes a great increase of PPAR-gamma expression in both HL-60 and U937 cells, whereas it does not modify the PPAR-alpha expression. This observation may account for the high synergistic effect displayed by HNE and PPAR-gamma ligands in the inhibition of cell growth and differentiation induction. These results represent the first evidence of the involvement of a product of lipid peroxidation in the modulation of PPAR ligand activity and suggest a relationship between HNE and PPAR ligand pathways in leukemic cell growth and differentiation.  相似文献   

12.
Elevated production of 4-hydroxy-trans-2-nonenal (HNE) occurs in numerous neurological disorders involving oxidative damage. HNE is metabolized to the non-toxic 4-hydroxy-trans-2-nonenoic acid (HNEAcid) by aldehyde dehydrogenases in the rat cerebral cortex. Based upon the structural similarity of HNEAcid to ligands of the gamma-hydroxybutyrate (GHB) receptor, we hypothesized that HNEAcid is an endogenous ligand for the GHB receptor. HNEAcid displaced the specific binding of the GHB receptor ligand (3)H-NCS382 (30 nm) in membrane preparations of human frontal cerebral cortex and whole rat cerebral cortex with IC(50s) of 3.9 +/- 1.1 and 5.6 +/- 1.2 micro m, respectively. Inhibition was attenuated when the carboxyl group of HNEAcid was replaced with an aldehyde or an alcohol. HNEAcid (300 micro m) did not displace the binding of beta-adrenergic receptor and GABA(B) receptor antagonists, demonstrating the selectivity of HNEAcid for the GHB receptor. HNEAcid is formed in homogenates of human frontal cortical gray matter in an NAD(+)-dependent (V(Max), 0.71 nmol/min/mg) and NADP(+)-dependent (V(Max), 0.12 nmol/min/mg) manner. Lastly, (3)H-NCS382 binding is elevated 2.7-fold with age in the cerebral cortex of rats. Our data demonstrate that an HNE metabolite, formed in rat and human brain, is a signaling molecule analogous to other bioactive lipid peroxidation products.  相似文献   

13.
Oxidative stress in cells and tissues leads to the formation of an assortment of lipid electrophiles, such as the quantitatively important 4-hydroxy-2-trans-nonenal (HNE). Although this cytotoxic aldehyde is atherogenic the mechanisms involved are unclear. We hypothesize that elevated HNE levels can directly inactivate esterase and lipase activities in macrophages via protein adduction, thus generating a biochemical lesion that accelerates foam cell formation and subsequent atherosclerosis. In the present study we examined the effects of HNE treatment on esterase and lipase activities in human THP1 monocytes/macrophages at various physiological scales (i.e., pure recombinant enzymes, cell lysate, and intact living cells). The hydrolytic activities of bacterial and human carboxylesterase enzymes (pnbCE and CES1, respectively) were inactivated by HNE in vitro in a time- and concentration-dependent manner. In addition, so were the hydrolytic activities of THP1 cell lysates and intact THP1 monocytes and macrophages. A single lysine residue (Lys105) in recombinant CES1 was modified by HNE via a Michael addition reaction, whereas the lone reduced cysteine residue (Cys389) was found unmodified. The lipolytic activity of cell lysates and intact cells was more sensitive to the inhibitory effects of HNE than the esterolytic activity. Moreover, immunoblotting analysis using HNE antibodies confirmed that several cellular proteins were adducted by HNE following treatment of intact THP1 monocytes, albeit at relatively high HNE concentrations (>50 μM). Unexpectedly, in contrast to CES1, the treatment of a recombinant human CES2 with HNE enhanced its enzymatic activity ∼3-fold compared to untreated enzyme. In addition, THP1 monocytes/macrophages can efficiently metabolize HNE, and glutathione conjugation of HNE is responsible for ∼43% of its catabolism. The functional importance of HNE-mediated inactivation of cellular hydrolytic enzymes with respect to atherogenesis remains obscure, although this study has taken a first step toward addressing this important issue by examining the potential of HNE to inhibit this biochemical activity in a human monocyte/macrophage cell line.  相似文献   

14.
Intra- and extra-mitochondrial Ca2+ participates in vital cellular processes. This work investigates the influence of 4-hydroxynonenal (HNE) on pro-oxidant-induced Ca2+ release from rat liver mitochondria. Ca2+ movements across the mitochondrial inner membrane, the pyridine nucleotide redox state and pyridine (nicotinamide) nucleotide hydrolysis were analysed. HNE did not influence Ca2+ uptake by mitochondria, but inhibited in a concentration-dependent manner Ca2+ release induced by t-butylhydroperoxide (tbh). Total inhibition was achieved with about 50 microM-HNE. Ca2+ release induced by the pro-oxidant alloxan was also inhibited by HNE. Oxidation of pyridine nucleotides, induced by tbh through the concerted action of glutathione peroxidase, glutathione reductase and the energy-linked transhydrogenase, was not affected by up to 50 microM-HNE. In contrast, HNE inhibited pyridine nucleotide hydrolysis in a concentration-dependent manner. The data suggest that HNE toxicity may be in part attributed to an impaired intramitochondrial Ca2+ homeostasis.  相似文献   

15.
Increase in 4‐hydroxy‐2‐nonenal (4HNE) due to oxidative stress has been observed in a variety of cardiac diseases such as diabetic cardiomyopathy. 4HNE exerts a damaging effect in the myocardium by interfering with subcellular organelles like mitochondria by forming adducts. Therefore, we hypothesized that increased 4HNE adduct formation in the heart results in proteasome inactivation in isoproterenol (ISO)‐infused type 1 diabetes mellitus (DM) rats. Eight‐week‐old male Sprague Dawley rats were injected with streptozotocin (STZ, 65 mg kg?1). The rats were infused with ISO (5 mg kg?1) for 2 weeks by mini pumps, after 8 weeks of STZ injection. We studied normal control (n = 8) and DM + ISO (n = 10) groups. Cardiac performance was assessed by echocardiography and Millar catheter at the end of the protocol at 20 weeks. Initially, we found an increase in 4HNE adducts in the hearts of the DM + ISO group. There was also a decrease in myocardial proteasomal peptidase (chymotrypsin and trypsin‐like) activity. Increases in cardiomyocyte area (446 ± 32·7 vs 221 ± 10·83) (µm2), per cent area of cardiac fibrosis (7·4 ± 0·7 vs 2·7 ± 0·5) and cardiac dysfunction were also found in DM + ISO (P < 0·05) relative to controls. We also found increased 4HNE adduct formation on proteasomal subunits. Furthermore, reduced aldehyde dehydrogenase 2 activity was observed in the myocardium of the DM + ISO group. Treatment with 4HNE (100 μM) for 4 h on cultured H9c2 cardiomyocytes attenuated proteasome activity. Therefore, we conclude that the 4HNE‐induced decrease in proteasome activity may be involved in the cardiac pathology in STZ‐injected rats infused with ISO. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

16.
It has recently been shown that the lipid peroxidation product 4-hydroxy-2-nonenal (HNE) forms a fluorescent hydroxyiminodihydropyrrole derivative with the epsilon-amino group of lysine residue. In this study, we raised a monoclonal antibody (mAb2C12) directed to the fluorophore-protein conjugate and found that the antibody was specific to the chromophore structure of the compound. Immunohistochemical analysis of atherosclerotic lesions from the human aorta showed that the fluorophore was indeed present in the lesions, in which intense positivity was primarily associated with macrophage-derived foam cells and thickening of the neointima of the arterial walls. Antigenic materials were also detected in the oxidatively modified low-density lipoprotein (LDL) with Cu(2+) and in the oxidatively modified bovine serum albumin with an iron/linoleic acid autoxidation system, indicating that the HNE, which originated from the peroxidation of polyunsaturated fatty acids, could be a potential source of the fluorescent chromophore in oxidized LDL.  相似文献   

17.
3'-NH2-BV-dUrd, the 3'-amino derivative of (E)-5-(2-bromovinyl)-2'-deoxyuridine, was found to be a potent and selective inhibitor of herpes simplex virus type 1 (HSV-1) and varicella-zoster virus (VZV) replication. 3'-NH2-BV-dUrd was about 4-12 times less potent but equally selective in its anti-herpes activity as BV-dUrd. Akin to BV-dUrd, 3'-NH2-BV-dUrd was much less inhibitory to herpes simplex virus type 2 than type 1. It was totally inactive against a thymidine kinase-deficient mutant of HSV-1. The 5'-triphosphate of 3'-NH2-BV-dUrd (3'-NH2-BV-dUTP) was evaluated for its inhibitory effects on purified herpes viral and cellular DNA polymerases. Among the DNA polymerases tested, HSV-1 DNA polymerase and DNA polymerase alpha were the most sensitive to inhibition by 3'-NH2-BV-dUTP (Ki values 0.13 and 0.10 microM, respectively). The Km/Ki ratio for DNA polymerase alpha was 47, as compared with 4.6 for HSV-1 DNA polymerase. Thus, the selectivity of 3'-NH2-BV-dUrd as an anti-herpes agent cannot be ascribed to a discriminative effect of its 5'-triphosphate at the DNA polymerase level. This selectivity most probably resides at the thymidine kinase level. 3'-NH2-BV-dUrd would be phosphorylated preferentially by the HSV-1-induced thymidine kinase (Ki 1.9 microM, as compared with greater than 200 microM for the cellular thymidine kinase), and this preferential phosphorylation would confine the further action of the compound to the virus-infected cell.  相似文献   

18.
19.
Summary

Rat liver mitochondria contain a specific Ca2+ release pathway which operates when intramitochondrial NAD+ is hydrolyzed to ADPribose and nicotinamide. The molecular details of this pathway are incompletely understood. It has been reported that NAD+ hydrolysis and therefore Ca2+ release stimulated by t-butylhydroperoxide is prevented by 4-hydroxynonenal (HNE). The reason underlying inhibition by HNE, however, remained unclear. It has also been reported that NAD+ hydrolysis and Ca2+ release are stimulated when some vicinal thiols are cross-linked, as shown with phenylarsine oxide or gliotoxin (GT). We now show that HNE also prevents the GT-induced Ca2+ release, but only when given before GT. Conversely, GT stimulates Ca2+ release only when given before HNE. Inhibition of Ca2+ release by HNE is reduced by its preincubation with thiol compounds, the effectiveness of which increases with decreasing pKa of their sulfhydryl group. Preincubation of HNE with glutathione at high, but not at low, pH similarly reduces inhibition of Ca2+ release by HNE. These findings provide evidence that HNE inhibition of Ca2+ release is due to a modification of mitochondrial thiolates in a way that their cross-linking is prevented, and give further insight into the regulation of Ca2+ release from intact mitochondria.  相似文献   

20.
《Free radical research》2013,47(10):1233-1238
Abstract

The lipid peroxidation product 4-hydroxynonenal (HNE) is a biomarker of oxidative stress which is essentially involved in the pathophysiology of many diseases. The analysis of HNE is challenging because this aldehyde is extremely reactive and thus unstable. Hence, we adopted a gas chromatography–mass spectrometry (GC–MS) method based on derivatization of HNE with pentafluorobenzylhydroxylamine–HCl followed by trimethylsilylation to trimethylsilyl ethers. Ions representative for a negative ion chemical ionization mode were recorded at m/z = 152 for HNE and at m/z = 162 for the deuterated analogon (HNE-d11) as internal standard. This excellent stable and precise GC–MS method was carefully validated for HNE, and showed good linearity (r2 = 0.998), and high specificity and sensitivity. Within-day precisions were 4.4–6.1% and between-day precisions were 5.2–10.2%. Accuracies were between 99% and 104% for the whole calibration range (2.5–250 nmol/L) of HNE.

To examine the versatility of this modified GC–MS method, we analyzed HNE in ethylenediaminetetraacetic acid (EDTA) plasma in a well-defined collective of migraine patients; recently published. The results underline our former observations that women with migraine are afflicted with increased levels of HNE. Patients with thyroidal dysfunction showed no significant HNE alterations. This was confirmed by normal HNE EDTA plasma levels in hyper- und hypothyroid Sprague-Dawley rats.

Taken together, the GC–MS method presented herein is of excellent quality to record oxidative stress-related bioactive HNE levels. This is important for a reorientation of oxidative stress analytics in other human diseases first of atherosclerosis and cancer.  相似文献   

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