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151.
Yannick?AllanoreEmail author Didier?Borderie Axel?Périanin Hervé?Lemaréchal Ohvanesse?Garabed?Ekindjian André?Kahan 《Arthritis research & therapy》2004,7(1):R93
We have reported previously that dihydropyridine-type calcium-channel antagonists (DTCCA) such as nifedipine decrease plasma
markers of oxidative stress damage in systemic sclerosis (SSc). To clarify the cellular basis of these beneficial effects,
we investigated the effects in vivo and in vitro of nifedipine on superoxide anion (O2
•-) production by peripheral blood monocytes. We compared 10 healthy controls with 12 patients with SSc, first after interruption
of treatment with DTCCA and second after 2 weeks of treatment with nifedipine (60 mg/day). O2
•- production by monocytes stimulated with phorbol myristate acetate (PMA) was quantified by the cytochrome c reduction method. We also investigated the effects in vitro of DTCCA on O2
•- production and protein phosphorylation in healthy monocytes and on protein kinase C (PKC) activity using recombinant PKC.
After DTCCA had been washed out, monocytes from patients with SSc produced more O2
•- than those from controls. Nifedipine treatment considerably decreased O2
•- production by PMA-stimulated monocytes. Treatment of healthy monocytes with nifedipine in vitro inhibited PMA-induced O2
•- production and protein phosphorylation in a dose-dependent manner. Finally, nifedipine strongly inhibited the activity of
recombinant PKC in vitro. Thus, the oxidative stress damage observed in SSc is consistent with O2
•- overproduction by primed monocytes. This was decreased by nifedipine treatment both in vivo and in vitro. This beneficial property of nifedipine seems to be mediated by its cellular action and by the inhibition of PKC activity.
This supports the hypothesis that this drug could be useful for the treatment of diseases associated with oxidative stress. 相似文献
152.
Neznanov N Neznanova L Kondratov RV O'Rourke DM Ullrich A Gudkov AV 《DNA and cell biology》2004,23(3):175-182
In contrast with hematopoietic cells and fibroblasts, which express mainly one form of protein tyrosine phosphatase (PTP) SHP-1 or SHP-2, epithelial cells like A431, HeLa, and 293 express both forms of PTP. These two PTP regulate NFkappaB activity differently; SHP-1 inhibits and SHP-2 stimulates NFkappaB activation. In epithelial cells the process of NFkappaB activation depends on the combination of two PTP activities. The activity of PTP SHP-1 dominates in this tandem according to our data. The signal regulatory protein (SIRPalpha) is the adapter and the substrate of PTP SHP-1 and SHP-2. We investigated the role of SIRPalpha and its dominant negative mutant in PTP activities in 293 cells. The overexpression of wild-type SIRPalpha suppresses the activities of both PTP, but has a stronger effect on PTP SHP-2, especially when this protein is overexpressed in 293 cells. In contrast with wild-type SIRPalpha, its dominant negative mutant acts predominantly against PTP SHP-1, and can be detected in the complex with PTP SHP-1. The expression of dominant negative mutant of SIRPalpha has an effect similar to the expression of dominant negative PTP SHP-1 in the process of NFkappaB activation. 相似文献
153.
Activation of stimulatory heterotrimeric G proteins increases glutathione and protects neuronal cells against oxidative stress 总被引:2,自引:0,他引:2
Oxidative glutamate toxicity in the neuronal cell line HT22 is a model for cell death by oxidative stress, where an excess of extracellular glutamate inhibits import of cystine, a building block of the antioxidant glutathione. The subsequent decrease in glutathione then leads to the accumulation of reactive oxygen species (ROS) and programmed cell death. We used pharmacological compounds known to interact with heterotrimeric G-protein signalling and studied their effects on cell survival, morphology, and intracellular events that ultimately lead to cell death. Cholera toxin and phorbol esters were most effective and prevented cell death through independent pathways. Treating HT22 cells with cholera toxin attenuated the glutamate-induced accumulation of ROS and calcium influx. This was, at least in part, caused by an increase in glutathione due to improved uptake of cystine mediated by the induction of the glutamate/cystine-antiporter subunit xCT or, additionally, by the up-regulation of the antiapoptotic protein Bcl-2. Gs activation also protected HT22 cells from hydrogen peroxide or inhibition of glutathione synthesis by buthionine sulfoximine, and immature cortical neurones from oxidative glutamate toxicity. Thus, this pathway might be more generally implicated in protection from neuronal death by oxidative stress. 相似文献
154.
A synthetic E7 gene of human papillomavirus type 16 that yields enhanced expression of the protein in mammalian cells and is useful for DNA immunization studies 总被引:15,自引:0,他引:15 下载免费PDF全文
A synthetic E7 gene of human papillomavirus (HPV) type 16 was generated that consists entirely of preferred human codons. Expression analysis of the synthetic E7 gene in human and animal cells showed levels of E7 protein 20- to 100-fold higher than those obtained with wild-type E7. Enhanced expression of E7 protein resulted from highly efficient translation, as well as increased stability of the E7 mRNA due to its codon optimization. Higher levels of E7 protein in cells transfected with synthetic E7 correlated with significant loss of cell viability in various human cell lines. In contrast, lower E7 protein expression driven by the wild-type gene resulted in a slight induction of cell proliferation. Furthermore, mice inoculated with plasmids expressing the synthetic E7 gene produced significantly higher levels of E7 antibodies than littermates injected with wild-type E7, suggesting that synthetic E7 may be useful for DNA immunization studies and the development of genetic vaccines against HPV-16. In view of these results, we hypothesize that HPVs may have retained a pattern of G + C content and codon usage distinct from that of their host cells in response to selective pressure. Thus, the nonhuman codon bias may have been conserved by HPVs to prevent compromising viability of the host cells by excessive viral early protein expression, as well as to evade the immune system. 相似文献
155.
Mogk A Schlieker C Strub C Rist W Weibezahn J Bukau B 《The Journal of biological chemistry》2003,278(20):17615-17624
ClpB of Escherichia coli is an ATP-dependent ring-forming chaperone that mediates the resolubilization of aggregated proteins in cooperation with the DnaK chaperone system. ClpB belongs to the Hsp100/Clp subfamily of AAA+ proteins and is composed of an N-terminal domain and two AAA-domains that are separated by a "linker" region. Here we present a detailed structure-function analysis of ClpB, dissecting the individual roles of ClpB domains and conserved motifs in oligomerization, ATP hydrolysis, and chaperone activity. Our results show that ClpB oligomerization is strictly dependent on the presence of the C-terminal domain of the second AAA-domain, while ATP binding to the first AAA-domains stabilized the ClpB oligomer. Analysis of mutants of conserved residues in Walker A and B and sensor 2 motifs revealed that both AAA-domains contribute to the basal ATPase activity of ClpB and communicate in a complex manner. Chaperone activity strictly depends on ClpB oligomerization and the presence of a residual ATPase activity. The N-domain is dispensable for oligomerization and for the disaggregating activity in vitro and in vivo. In contrast the presence of the linker region, although not involved in oligomerization, is essential for ClpB chaperone activity. 相似文献
156.
Modulation of the classical multidrug resistance (MDR) phenotype by RNA interference (RNAi) 总被引:101,自引:0,他引:101
For reversal of MDR1 gene-dependent multidrug resistance (MDR), two small interfering RNA (siRNA) constructs were designed to inhibit MDR1 expression by RNA interference. SiRNA duplexes were used to treat human pancreatic carcinoma (EPP85-181RDB) and gastric carcinoma (EPG85-257RDB) cells. In both cellular systems, siRNAs could specifically inhibit MDR1 expression up to 91% at the mRNA and protein levels. Resistance against daunorubicin was decreased to 89% (EPP85-181RDB) or 58% (EPG85-257RDB). The data indicate that this approach may be applicable to cancer patients as a specific means to reverse tumors with a P-glycoprotein-dependent MDR phenotype back to a drug-sensitive one. 相似文献
157.
NSF and p97/VCP: similar at first, different at last 总被引:4,自引:0,他引:4
N-Ethylmaleimide sensitive factor (NSF) and p97/valosin-containing protein (VCP) are distantly related members of the ATPases associated with a variety of cellular activities (AAA) family of proteins. While both proteins have been implied in cellular morphology changes involving membrane compartments or vesicles, more recent evidence seems to imply that NSF is primarily involved in the soluble NSF attachment receptor (SNARE)-mediated vesicle fusion by disassembling the SNARE complex whereas p97/VCP is primarily involved in the extraction of membrane proteins. These functional differences are now corroborated by major structural differences based on recent crystallographic and cryo-electron microscopy studies. This review discusses these recent findings. 相似文献
158.
Wiesmann F Frydrychowicz A Rautenberg J Illinger R Rommel E Haase A Neubauer S 《American journal of physiology. Heart and circulatory physiology》2002,283(3):H1065-H1071
Because of its complex geometry, assessment of right ventricular (RV) function is more difficult than it is for the left ventricle (LV). Because gene-targeted mouse models of cardiomyopathy may involve remodeling of the right heart, the purpose of this study was to develop high-resolution functional magnetic resonance imaging (MRI) for in vivo quantification of RV volumes and global function in mice. Thirty-three mice of various age were studied under isoflurane anesthesia by electrocardiogram-triggered cine-MRI at 7 T. MRI revealed close correlations between RV and LV stroke volume and cardiac output (r = 0.97, P < 0.0001 each). Consistent with human physiology, murine RV end-diastolic and end-systolic volumes were significantly higher compared with LV volumes (P < 0.05 each). MRI in mice with LV heart failure due to myocardial infarction revealed significant structural and functional changes of the RV, indicating RV dysfunction. Hence, MRI allows for the quantification of RV volumes and global systolic function with high accuracy and bears the potential to evaluate mechanisms of RV remodeling in mouse models of heart failure. 相似文献
159.
160.
Discovering lactic acid bacteria by genomics 总被引:25,自引:0,他引:25
Klaenhammer T Altermann E Arigoni F Bolotin A Breidt F Broadbent J Cano R Chaillou S Deutscher J Gasson M van de Guchte M Guzzo J Hartke A Hawkins T Hols P Hutkins R Kleerebezem M Kok J Kuipers O Lubbers M Maguin E McKay L Mills D Nauta A Overbeek R Pel H Pridmore D Saier M van Sinderen D Sorokin A Steele J O'Sullivan D de Vos W Weimer B Zagorec M Siezen R 《Antonie van Leeuwenhoek》2002,82(1-4):29-58
This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, nvironmental habitat, and its role in fermentation, bioprocessing, or probiotics. For those projects where genome sequence data were available by March 2002, summaries include a listing of key statistics and interesting genomic features. These efforts will revolutionize our molecular view of Gram–positive bacteria, as up to 15 genomes from the low GC content lactic acid bacteria are expected to be available in the public domain by the end of 2003. Our collective view of the lactic acid bacteria will be fundamentally changed as we rediscover the relationships and capabilities of these organisms through genomics. 相似文献