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1.
Cytochrome P450 2E1-derived reactive oxygen species mediate paracrine stimulation of collagen I protein synthesis by hepatic stellate cells. 总被引:3,自引:0,他引:3
Natalia Nieto Scott L Friedman Arthur I Cederbaum 《The Journal of biological chemistry》2002,277(12):9853-9864
To evaluate possible fibrogenic effects of CYP2E1-dependent generation of reactive oxygen species, a model was developed using co-cultures of HepG2 cells, which do (E47 cells) or do not (C34 cells) express cytochrome P450 2E1 (CYP2E1) with stellate cells. There was an increase in intra- and extracellular H(2)O(2), lipid peroxidation, and collagen type I protein in stellate cells co-cultured with E47 cells compared with stellate cells alone or co-cultured with C34 cells. The increase in collagen was prevented by antioxidants and a CYP2E1 inhibitor. CYP3A4 did not mimic the stimulatory effects found with CYP2E1. Collagen mRNA levels remained unchanged, and pulse-chase analysis indicated similar half-lives of collagen I protein between both co-cultures. However, collagen protein synthesis was increased in E47 co-culture. Hepatocytes from pyrazole-treated rats (with high levels of CYP2E1) induced collagen protein in primary stellate cells, and antioxidants and CYP2E1 inhibitors blocked this effect. These results suggest that increased translation of collagen mRNA by CYP2E1-derived reactive oxygen species is responsible for the increase in collagen protein produced by the E47 co-culture. These co-culture models may be useful for understanding the impact of CYP2E1-derived ROS on stellate cell function and activation. 相似文献
2.
Natalia Ermak Bernard Lacour Françoise Goirand Stéphanie Vicca 《Biochemical and biophysical research communications》2010,393(4):783-787
We compared the apoptotic mechanism involved in U937 human monocytic cell line in presence of oxidized low-density lipoproteins (oxLDL) obtained after treatment with hypochlorous acid (HOCl) or copper (Cu).Both types of oxLDL induced U937 apoptotic cell death via the mitochondrial pathway. In contrast to HOCl-oxLDL, Cu-oxLDL induced apoptosis via a caspase-independent mechanism, with no activation of pro-caspase-3, but via the release of apoptosis inducing factor (AIF) from mitochondria.The apoptotic program of the monocyte differs depending on the mode of LDL oxidation, based on differences in the oxidatively modified components of the two oxLDL types. 相似文献
3.
Natalia V. Engelhardt Valentina M. Factor Alexander L. Medvinsky Vladimir N. Baranov Maria N. Lazareva Valentina S. Poltoranina 《Differentiation; research in biological diversity》1993,55(1):19-26
Abstract. The A6 antigen - a surface-exposed component shared by mouse oval and biliary epithelial cells - was examined during prenatal development of mouse in order to elucidate its relation to liver progenitor cells. Immunohistochemical demonstration of the antigen was performed at the light and electron microscopy level beginning from the 9.5 day of gestation (26–28 somite pairs).
Up to the 11.5 day of gestation A6 antigen is found only in the visceral endoderm of yolk sac and gut epithelium, while liver diverticulum and liver are A6-negative. In the liver epithelial lineages A6 antigen behaves as a strong and reliable marker of biliary epithelial cells where it is found beginning from their emergence on the 15th day of gestation. It was not revealed in immature hepato-cytes beginning from the 16th day of gestation. However weak expression of the antigen was observed in hepato-blasts on 12–15 days of gestation possibly reflecting their ability to differentiate along either hepatocyte or biliary epithelial cell lineages.
Surprisingly, A6 antigen turned out to be a peculiar marker of the crythroid lineage: in mouse fetuses it distinguished A6 positive liver and spleen erythroblasts from A6 negative early hemopoietic cells of yolk sac origin. Moreover in the liver, A6 antigen probably distinguishes two waves of erythropoiesis: it is found on the erythroblasts from the 11.5 day of gestation onward while first extravascular erythroblasts appear in the liver on the 10th day of gestation. Both fetal and adult erythrocytes are A6-negative.
In the process of organogenesis A6 antigen was revealed in various mouse fetal organs. Usually it was found on plasma membranes of mucosal or ductular epithelial cells. Investigation of A6 antigen's physiological function would probably explain such specific localization. 相似文献
Up to the 11.5 day of gestation A6 antigen is found only in the visceral endoderm of yolk sac and gut epithelium, while liver diverticulum and liver are A6-negative. In the liver epithelial lineages A6 antigen behaves as a strong and reliable marker of biliary epithelial cells where it is found beginning from their emergence on the 15th day of gestation. It was not revealed in immature hepato-cytes beginning from the 16th day of gestation. However weak expression of the antigen was observed in hepato-blasts on 12–15 days of gestation possibly reflecting their ability to differentiate along either hepatocyte or biliary epithelial cell lineages.
Surprisingly, A6 antigen turned out to be a peculiar marker of the crythroid lineage: in mouse fetuses it distinguished A6 positive liver and spleen erythroblasts from A6 negative early hemopoietic cells of yolk sac origin. Moreover in the liver, A6 antigen probably distinguishes two waves of erythropoiesis: it is found on the erythroblasts from the 11.5 day of gestation onward while first extravascular erythroblasts appear in the liver on the 10th day of gestation. Both fetal and adult erythrocytes are A6-negative.
In the process of organogenesis A6 antigen was revealed in various mouse fetal organs. Usually it was found on plasma membranes of mucosal or ductular epithelial cells. Investigation of A6 antigen's physiological function would probably explain such specific localization. 相似文献
4.
Previous studies by us and others established that cell-cell adhesion is mediated by specific carbohydrate-to-carbohydrate
interaction (CCI). Those previous studies were based on various biochemical and biophysical approaches, including the use
of labeled glycosyl epitopes with fluorescent tag. However, these methods ideally require that the glycosyl epitope must be
fixed to a solid phase molecule, preferably with multivalency. The purpose of the present study is to establish a CCI process
using specific glycosyl residues conjugated to biotinylated diaminopyridine (BAP), and to observe: (i) clear occurrence of
homotypic CCI between “Os Fr.B” having 5–6 GlcNAc termini, vs. absence of such homotypic CCI between “Os Fr.1” having 2 GlcNAc termini; (ii) occurrence of heterotypic CCI between GM3
ganglioside and Os Fr.B, vs. absence of such heterotypic CCI between GM3 and Os Fr.1. Interaction between Os Fr.B-BAP conjugate and Os Fr.B-ceramide
mimetic (Os Fr.B-mCer) was demonstrated based on two experiments: (i) dose-dependent binding of Os Fr.B-BAP conjugate to polystyrene
plates coated with Os Fr.B-mCer was observed in the presence of bivalent cation, a prerequisite for all CCI processes, and
such binding was abolished by EDTA; (ii) binding between equal nanomolar Os Fr.B-BAP and Os Fr.B-mCer was inhibited by mM
concentration Os Fr.B without conjugate, in dose-dependent manner. Thus, cell adhesion processes based on homotypic CCI between
N-linked glycans having multiple GlcNAc termini, and heterotypic CCI between GM3 and such glycans, were clearly observed using
BAP conjugates of glycosyl epitopes. 相似文献
5.
Chung-Te Chang Natalia Bercovich Belinda Loh Stefanie Jonas Elisa Izaurralde 《Nucleic acids research》2014,42(8):5217-5233
The removal of the 5′-cap structure by the decapping enzyme DCP2 and its coactivator DCP1 shuts down translation and exposes the mRNA to 5′-to-3′ exonucleolytic degradation by XRN1. Although yeast DCP1 and DCP2 directly interact, an additional factor, EDC4, promotes DCP1–DCP2 association in metazoan. Here, we elucidate how the human proteins interact to assemble an active decapping complex and how decapped mRNAs are handed over to XRN1. We show that EDC4 serves as a scaffold for complex assembly, providing binding sites for DCP1, DCP2 and XRN1. DCP2 and XRN1 bind simultaneously to the EDC4 C-terminal domain through short linear motifs (SLiMs). Additionally, DCP1 and DCP2 form direct but weak interactions that are facilitated by EDC4. Mutational and functional studies indicate that the docking of DCP1 and DCP2 on the EDC4 scaffold is a critical step for mRNA decapping in vivo. They also revealed a crucial role for a conserved asparagine–arginine containing loop (the NR-loop) in the DCP1 EVH1 domain in DCP2 activation. Our data indicate that DCP2 activation by DCP1 occurs preferentially on the EDC4 scaffold, which may serve to couple DCP2 activation by DCP1 with 5′-to-3′ mRNA degradation by XRN1 in human cells. 相似文献
6.
Nina I. Smirnova Galina V. Chekhovskaya Natalia I. Davidova Ludmila F. Livanova Galina A. Yeroshenko 《FEMS microbiology letters》1996,136(2):175-180
Abstract The presence of a temperate phage was demonstrated in a strain of Vibrio cholerae O139 isolated from a patient. Spontaneous variants with translucent colonies had lost this phage. The loss of the phage was associated with increased hydrophobicity, indicating the loss of the capsule. These clones were sensitive to serum bactericidal activity, showed decreased expression of such presumed virulence factors as proteases, motility and mannose-sensitive pili. Furthermore, excision of the phage made the strain dependent on purines for growth. 相似文献
7.
8.
It is established that carboxypeptidase H activity increases as affected by various stress factors in the rat brain departments. The increase of the enzyme activity because of the emotional-pain stress is of continuous character. Possible role of carboxypeptidase H in the development of the stress response is discussed. 相似文献
9.
Effect of applied and internal hormones on vitrification and apical necrosis of different plants cultured in vitro 总被引:2,自引:0,他引:2
Natalia V. Kataeva Irena G. Alexandrova Raisa G. Butenko Elena V. Dragavtceva 《Plant Cell, Tissue and Organ Culture》1991,27(2):149-154
Development of vitrification and apical necrosis was followed in Camellia sinensis, Gerbera jamesonii, Malus domestica and hybrid Populus tremula x P. alba shoots cultured in vitro on Murashige & Skoog (MS) medium with different concentrations of growth regulators. High humidity in the culture vessels and excess of BA in the medium were found to be the major factors influencing vitrification. Lack of exogenous cytokinin in the medium during successive subcultures induced apical necrosis in poor-rooting species (Malus domestica, Camellia sinensis). The level of internal phytohormones (ABA, IAA, IPA, 2iP, Z, ZR) was determined in the apple shoots by means of ELISA. The content of internal cytokinins in the vitrified apple shoots was several times greater than in normal ones, which supports the hypothesis that excess of cytokinins, inducing rapid divisions of cells in meristems in the atmosphere with high humidity, is responsible for vitrification. Apical necrosis of the plantlets that appeared after cultivation on cytokinin-free medium is the result of deficiency in endogenous hormones in apple shoots and this being confirmed by analysis of endogenous hormones in apple shoots.Abbreviations BA
benzyladenine
- BHT
butylated hydroxy-toluene
- ABA
abscisic acid
- IAA
indole-3-acetic acid
- ELISA
enzyme-linked immunosorbent assay
- IPA
isopentenyladenosine
- 2iP
isopentenyladenine
- NAA
naphthyl-3-acetic acid
- TBS
trishydroxymethylaminomethane buffered saline
- TLC
thin layer chromatography
- Z
zeatin
- ZR
zeatin riboside 相似文献
10.
The thermotropic properties of multilamellar liposomes from egg yolk lecithin, hydrogenized egg yolk lecithin and several mixtures of these two lipids were studied with the application of excimer--forming optical probe pyrene and microcalorimetry. It was discovered that when the proportion of the egg yolk lecithin in the lipid mixture was raised the temperature of the main phase transition reduced. For all this, independent of the lipid mixture composition when the temperature was raised, apparently, polarity of pyrene microenvironment in the liposomes bilayers decreased. On the basis of the analysis of solidus and liquidus curves obtained from calorimetric studies of the lipid mixtures and bend points of Arrhenius anamorphose obtained during the pyrene excimer formation measurements some conclusions were made about the role of unmodified and hydrogenized egg yolk lecithin cluster formation in the determination of thermotropic properties of the liposomes from the above two lipids mixtures. High temperature phase transition discovered for the egg yolk lecithin while measuring the pyrene excimer formation is proposed to be closely connected with temperature-dependent changes in the organization of phospholipid heads on the interphase bilayer/H2O solution. 相似文献