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E Toniato

Publications and source records attributed to E Toniato.

At least 19 recordsLinked to original sources
PubMed2005

Oxidative stress and cardiovascular risk: the role of vascular NAD(P)H oxidase and its genetic variants.

Several risk factors for coronary artery disease (CAD) induce atherosclerosis through endothelial activation and dysfunction, and ample evidence now suggests that the balance between production and removal of reactive oxygen species (ROS) - a condition termed oxidative stress - is implicated in such processes. A main source of ROS in vascular cells is the reduced nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase system. This is a membrane-associated enzyme, composed of five subunits, catalyzing the one-electron reduction of oxygen, using NADH or NADPH as the electron donor. One of the system subunits, termed p22-phox, has a polymorphic site on exon 4, associated with variable enzyme activity. This polymorphism is generated by a point mutation (C(242)T) producing a substitution of histidine with tyrosine at position 72, which affects one of the heme binding sites essential for the NAD(P)H enzyme activity. The consequent decrease of superoxide production thus characterizes a phenotype candidate for conferring to the carrier a reduced susceptibility to CAD. At present, however, the body of evidence from current literature is not yet sufficient to confirm or exclude the hypothesis that the C(242)T polymorphism protects from CAD. The functional effects of this polymorphism and the potential and its pathophysiological consequences also need further investigation.

Coronary Artery Disease↗
PubMed2001

Nucleotide sequence, transcription map, and mutation analysis of the 13q14 chromosomal region deleted in B-cell chronic lymphocytic leukemia.

Deletions of the 13q14 chromosome region are associated with B-cell chronic lymphocytic leukemia (B-CLL) and several other types of cancer, suggesting the presence of a tumor suppressor gene. In previous studies the minimal region of deletion (MDR) was mapped to a less than 300-kilobase (kb) interval bordered by the markers 173a12-82 and 138G4/1.3R. For the identification of the putative tumor suppressor gene, the entire MDR (approximately 347 kb) has been sequenced, and transcribed regions have been identified by exon trapping, EST-based full-length complementary DNA cloning, database homology searches, and computer-assisted gene prediction analyses. The MDR contains 2 pseudogenes and 3 transcribed genes: CAR, encoding a putative RING-finger containing protein; 1B4/Leu2, generating noncoding transcripts; and EST70/Leu1, probably representing another noncoding gene (longest open reading frame of 78 codons). These genes have been sequenced in 20 B-CLL cases with 13q14 hemizygous deletion, and no mutations were found. Moreover, no somatic variants were found in the entire MDR analyzed for nucleotide substitutions by a combination of direct sequencing and fluorescence-assisted mismatch analysis in 5 B-CLL cases displaying 13q14-monoallelic deletion. The nondeleted allele of the CAR and EST70/Leu1 genes was expressed in B-CLL specimens, including those with monoallelic loss, whereas no expression of 1B4/Leu2 was detectable in B-CLL, regardless of the 13q14 status. These results indicate that allelic loss and mutation of a gene within the MDR is an unlikely pathogenetic mechanism for B-CLL. However, haplo-insufficiency of one of the identified genes may contribute to tumorigenesis. (Blood. 2001;97:2098-2104)

Animals↗
PubMed2001

The murine p202 protein, an IFN-inducible modulator of transcription, is activated by the mitogen platelet-derived growth factor.

p202 is a murine interferon (IFN)-inducible protein belonging to a cluster of IFN-inducible genes (the 200 family) located in a segment of chromosome 1. It is a nuclear DNA-binding protein that is able to modulate transcription by interacting with a heterogeneous set of transcription factors, including NF-kappaB, (p50/p65), AP-1, c-fos, c-jun, and RB-1. The p202 protein is believed to attenuate cell growth/proliferation, mainly through the activation of IFN-stimulated of gene factor 3 (ISGF3), which binds IFN-stimulated response elements (ISRE) located in the promoters of type I IFN genes. In this report, we show that the p202 gene can also be induced by platelet-derived growth factor (PDGF), a mitogen known to drive G(0)-arrested cells toward reentry into the cell cycle. PDGF transiently enhances the steady-state mRNA level of p202 and increases the p202 protein level independently from IFN signaling, by acting at the transcriptional level on its promoter. The kinetics of p202 induction by PDGF are faster and more transient than those of IFN. These data identify p202 as a member of the IFN-inducible gene family that can be directly regulated by mitogenic stimuli.

3T3 Cells↗
PubMed1999

Angiotensin II stimulates intercellular adhesion molecule-1 (ICAM-1) expression by human vascular endothelial cells and increases soluble ICAM-1 release in vivo.

BACKGROUND: We evaluated whether angiotensin II (Ang II) influenced intercellular adhesion molecule (ICAM)-1 expression by human vascular endothelial cells derived from umbilical cord veins (HUVECs) and plasma soluble ICAM-1 levels in vivo. METHODS AND RESULTS: Cultured HUVECs were incubated with Ang II (from 10(-9) to 10(-6) mol/L) with or without candesartan and PD12319 (inhibitors of Ang II AT(1) and AT(2) receptors, respectively) for various times up to 4 hours. Total RNA was then extracted from HUVECs, and Northern blots were probed with a 1.9-kb ICAM-1 cDNA fragment. HUVEC supernatants were used to assess soluble ICAM-1 release by ELISA. Northern blot analysis detected a strong increase of ICAM-1 mRNA after 2-hour incubation with Ang II. The response was inhibited by candesartan. Soluble ICAM-1 release by HUVECs also increased (P<0. 002) after 2-hour Ang II stimulation. In vivo, Ang II (at an initial rate of 1.0 ng. kg(-1). min(-1), to be increased each 30 minutes by 2.0 ng. kg(-1). min(-1) to the final rate of 7.0 ng. kg(-1). min(-1)) was infused in 8 normotensive and 12 essential hypertensive individuals. In the latter, Ang II was reinfused after 4 weeks on either placebo (n=3), losartan (50 mg UID, n=5), or atenolol (50 mg UID, n=4) treatment. Plasma soluble ICAM-1 levels increased after Ang II infusion in hypertensives and normotensives (P<0.0001 after 90 minutes). Losartan reduced baseline soluble ICAM-1 levels (P<0.05) and Ang II-related ICAM-1 increments. CONCLUSIONS: Ang II upregulates ICAM-1 expression by HUVECs and stimulates in vitro and in vivo soluble ICAM-1 release. AT(1) receptor blockade inhibits such endothelial effects of Ang II.

Adult↗
PubMed1999

p16 (INK4a, MTS-1) gene polymorphism and methylation status in human pituitary tumours.

OBJECTIVE: The p16 gene, which encodes a physiological inhibitor of the cyclin D-CDK4 complex, is now considered as an important tumour-suppressor gene in a variety of tumours. A marked reduction of its expression has been reported to occur without significant genetic alterations in human pituitary adenomas, although rare point mutations of uncertain functional significance have been described. On the other hand, p16 gene silencing due to hypermethylation has been reported in several human primary tumours. The aim of this study was to further investigate the pathogenetic events leading to p16 gene inactivation in pituitary tumours. DESIGN: To screen a european series of human pituitary tumours for p16 gene alterations and possible gene hypermethylation. PATIENTS: A representative series of 31 human pituitary tumours-30 macroadenomas, including a MEN-1 non-secreting pituitary adenoma and a non-MEN-1 familial giant GH-secreting adenoma, and one FSH-secreting pituitary carcinoma-was studied. METHODS: Polymerase chain reaction/single strand conformation polymorphism (PCR-SSCP) analysis was used to screen for p16 gene alterations in all cases. Direct sequencing of PCR-products was obtained by the di-deoxynucleotide method where suspected abnormalities of the PCR-SSCP analysis were observed. In 24 samples, a methylation-specific PCR assay (MSP-PCR) was used to determine p16 gene methylation status. RESULTS: Two sporadic cases of pituitary adenomas had a similar single A to G base substitution leading to an heterozygous Ala140Thr p16 polymorphism, which has not previously been described in such tumours, but is known to be functionally silent. No other p16 abnormality could be suspected from PCR-SSCP analysis in this series. In contrast, the presence of methylated-specific PCR products was observed in 20/24 cases (83.3%). CONCLUSIONS: This study confirms that p16 gene mutations are not involved in the pathogenesis of human pituitary tumours, although polymorphisms can be demonstrated, depending on the population considered. In contrast, the high incidence of hypermethylation of the p16 gene suggests that such an alteration occurs early in pituitary tumours, and may play a role in pituitary tumorigenesis.

Adenoma↗
PubMed1998

Two gamma-interferon-activation sites (GAS) on the promoter of the human intercellular adhesion molecule (ICAM-1) gene are required for induction of transcription by IFN-gamma.

We describe the molecular features of the interferon (IFN)-gamma-mediated transcription of the human intercellular adhesion molecule (ICAM-1) gene. We identified putative IFN-gamma-activated sites (GAS) distributed throughout a large segment of the ICAM-1 promoter (4.0 kb region). Using computer-assisted search, these sequences were similar to potential IFN-gamma responsive elements that have a core sequence 5'-TTNCNNNAA-3'. In this report we show that in the ICAM-1 promoter a GAS site is located at -115 from the translation initiation site, and binds with strong affinity to IFN-gamma-activated Signal Transducers and Activators of Transcription (STAT1) homodimers. The same sequence is responsible for the IFN-gamma-mediated transcription of the ICAM-1 gene. Moreover, we present evidence that a more distal GAS element that maps at -2787 from the translation initiation site, binds IFN-gamma-activated STAT1 dimers with lower affinity. Multimeric copies of such GAS sequence inserted into a tkCAT minimal promoter can drive transcription, demonstrating that the -2787 bp GAS element has an independent functional activity upon binding of IFN-gamma-activated STAT1 proteins as documented by in vitro binding assays. Furthermore, using recombinant ICAM-CAT mutants, we show that, in vivo, the -2787 GAS, but not a mutagenized -2787 GAS site, when coupled to the more proximal -115 GAS element, has an additive effect in enhancing the IFN-gamma-mediated transcription of ICAM-1 promoter. Nevertheless, using a recombinant construct bearing the wild type -2787 GAS element and a mutagenized -115 GAS element, we could not detect any transcription after transfection of U937 recipient cells, suggesting that the -2787 bp GAS element is not sufficient as such for gene activation, but can cooperate with its cognate proximal sequence to give full function to the ICAM-1 promoter during the IFN-gamma response. Taken together these data provide evidence that two GAS sites are required for the full potential activity in the mechanism of ICAM-1 gene activation by IFN-gamma.

5' Untranslated Regions↗
PubMed1996

Phospholipase A2 activity and calpactin I levels in rat lymphokine-activated killer cells: correlation with the cytotoxic activity.

In the present paper we have shown evidence for a significant increase of type II sPLA2 activity in A-LAK cells. The A-LAK-mediated cytotoxicity against YAC-1 target cells was strongly inhibited by two inhibitors of sPLA2, p-BPB and mepacrine, suggesting the involvement of this enzyme in the lytic mechanism of A-LAK. On the other hand, stimuli such as A23187 ionophore and TPA, which were able to induce in control cells an increased AA release, failed to cause this effect in IL-2-treated cells, suggesting that PLA2 was not active in these cells. Thus, we analyzed the levels of calpactin I, which is considered to be involved in the down-regulation of PLA2 activity. HrIL-2 treatment led to an increased expression of calpactin I at both the RNA and the protein level. A substantial portion of calpactin I was associated with the external surface of A-LAK and was able to exert a strong inhibitory effect on a purified porcine pancreatic PLA2 activity in vitro. Our results suggest that the role of calpactin I could be relevant to regulate PLA2 activity, and to protect the effector cells against a possible toxic effect which this enzyme could exert if present at high levels.

Animals↗
PubMed1996

Involvement of an arachidonic-acid-dependent pathway in the interferon-beta-mediated expression of C202 gene in Ehrlich-ascites-tumor cells.

We have investigated the signal transduction mechanism of the expression of the C202 gene mediated by interferon beta (IFN-beta) in the murine Ehrlich's ascites tumor cell line. We have shown that treatment of cells with IFN-beta transiently enhances within minutes the release of free arachidonic acid through membrane phospholipase activity. Furthermore, prior treatment with either p-bromophenacyl bromide, an antagonist of both cytosolic and secretory phospholipase A2, or neomycin, which blocks phospholipase C activity, significantly decreased the activation of the murine IFN-beta-inducible gene, C202. Moreover, an increase of the expression of the C202 gene was observed after blocking of both the cyclooxygenase and lipoxygenase pathways. This suggests that further metabolism of arachidonic acid to epoxides via epoxygenase-catalysed pathways may be a mechanism by which second messengers for IFN-beta-mediated effects on C202 gene expression are generated. Taken together, these results indicate that lipids as second messengers may be important mediators in the IFN-beta-based activation of C202 gene expression.

Animals↗
PubMed1996

Molecular diagnosis of p53 mutations in gastric carcinoma by touch preparation.

Thirty-one tumor samples from selected cases of gastric carcinoma were analyzed for mutations of the p53 tumor suppressor gene. Template DNA was prepared according to the touch preparation procedure, which allowed us to isolate clusters of neoplastic cells out of a stromal cellular background to be used as a template in the amplification of target exons of the p53 locus. In our present study, by polymerase chain reaction/single strand conformation polymorphism analysis we give evidence of p53 mutations occurring in the DNA-binding core domain of the protein (exons 5 through 9), which are clustered in stages III and IV of the disease (six mutations out of seventeen samples; 35%). No p53 mutations were detected in fourteen gastric cancer samples at I and II stages. Beside the use of conventional molecular scanning procedures, our study proposes the application of the touch preparation method to increase the detection of genetic alterations in human solid tumors.

Base Sequence↗
PubMed1995

Heavy-metal modulation of the human intercellular adhesion molecule (ICAM-1) gene expression.

The intercellular adhesion molecule 1 (ICAM-1) can be induced on many different cell types by a set of various modulators (IL1 beta, TNF, LPS, IFN-gamma), which are released during the inflammatory process. We have investigated the possibility that other factors, related to the stress and biophysical perturbations of the inflammatory response, may also modulate ICAM-1. Here, we report that heavy metals, in particular zinc, can enhance the expression of the ICAM-1 gene on cells actively involved at different levels during inflammation. Kinetic studies of ICAM-1 gene expression shows a maximum level of induction 4 h after treatment with metals, followed by a rapid decrease to basal levels within 12 h. The effect on enhanced gene expression is mostly due to a rapid increase of the transcriptional rate as shown by nuclear run-on experiments. In B lymphoblastoid cells, but not in fibroblasts, the increase in RNA expression seems significantly greater that the subsequent increase in protein expression, suggesting that a further point of post-transcriptional regulation of ICAM-1 occurs and may be linked to the cellular specificity. may be linked to the cellular specificity.

Cadmium↗
PubMed1995

Transcriptional modulation of the human intercellular adhesion molecule gene I (ICAM-1) by retinoic acid in melanoma cells.

Retinoids play an important role as differentiating agents in a variety of normal and neoplastic cells and have been reported to induce ICAM-1 levels in melanomas, a phenomenon that we confirm in this paper. The effects of retinoids on gene expression usually involve the binding of specific retinoic acid receptor trans-acting factors (RARs) with their ligands, which then interact with specific target sites, the retinoic acid responsive elements (RAREs) present in the promoters of responsive genes. In the case of ICAM-1, we have cloned and analyzed the proximal regulatory region of the human gene. We show that the ICAM-1 promoter is RA-inducible, that it contains a putative consensus RARE (GGGTCATCGCCCTGCC), which binds in vitro RAR alpha complemented with RXRs, and that mutation of the RARE abrogates promoter responsiveness to RA. These studies allow ICAM-1 to be added to the list of genes transcriptionally activated by RA acting through an RARE element.

Base Sequence↗
PubMed1991

Enhancement of natural-killer-cell susceptibility of human breast-cancer cells by estradiol and v-Ha-ras oncogene.

Natural killer (NK) cells are putative components of the cellular immune response to transformed cells. Since both estradiol treatment and ras-oncogene overexpression enhance tumorigenicity of hormone-dependent breast-cancer cells, we studied the effects of estrogen and of the activated v-Ha-ras oncogene on NK susceptibility of MCF-7 human breast-cancer cells. MCF-7 cells were sensitive to cytolysis mediated by resting and IL2-activated peripheral-blood non-adherent lymphocytes. Lysis appeared to be mediated by NK cells, since it was abrogated by treatment of effector cells with alpha-CD16 monoclonal antibody (MAb) plus complement (c'). Estradiol treatment of MCF-7 cells was able to significantly increase their sensitivity to the lysis by IL2-activated and unactivated peripheral-blood lymphocytes, as early as 24 hr throughout 10 days of hormone treatment. Hormone-insensitive, estrogen-receptor-negative breast-cancer cells (BT20) did not change their NK susceptibility after estradiol treatment. Increased NK susceptibility was also observed in v-Ha-ras-transfected and oncogene product overexpressing MCF-7 cells (MCF-7-ras) with respect to cells transfected with the selectable gene marker gpt alone (MCF-7-gpt). Overexpression of v-Ha-ras appeared to be able to bypass the need for estrogen to increase NK susceptibility, since estradiol-treated MCF-7-ras cells were not lysed more than untreated MCF-7-ras cells. The enhancement of NK susceptibility observed after both estradiol treatment and v-Ha-ras overexpression suggests that the hormone-mediated and the ras-oncogene-mediated signalling systems share events involved in the control of tumor-cell/host-effector-cell interactions.

Breast Neoplasms↗
PubMed1989

Interferons as gene activators. Indications for repeated gene duplication during the evolution of a cluster of interferon-activatable genes on murine chromosome 1.

We have described earlier a gene cluster, including at least six interferon-activatable genes closely linked to the erythroid alpha spectrin locus and the serum amyloid P-component locus on murine chromosome 1. Here, we report that sequences of three genes from the cluster (the 201, 202, and 204 genes) are very similar in a segment extending from at least 550 nucleotides upstream of the 3' end of the transcription initiation region to beyond the first exon intron border (96% similarity between the 202 and 204 genes and 89% similarity between the 201 and 204 genes). This region contains the following two types of interferon-responsive enhancers: a GA box and a Friedman Stark sequence. The proteins coded for by the 202 gene (51 kDa) and the 204 gene (72 kDa) are hydrophilic. The amino acids have been conserved in the two proteins in 47% of the sequence. Each protein includes two apparently contiguous, approximately 200-amino acid long segments with much sequence similarity (27% in the 202 protein and 34% in the 204 protein). These segments are preceded in the 204 protein only by a segment including four perfect and three imperfect repeats of a 7 amino acid sequence. These and other data suggest that the evolution of the gene cluster involved the duplication of a DNA segment generating a double length transcription unit and subsequent divergence and duplication of this unit giving rise to at least two interferon-activatable genes (the 202 and 204 genes).

Amino Acid Sequence↗
PubMed1989

Interferons as gene activators: a cluster of six interferon-activatable genes is linked to the erythroid alpha-spectrin locus on murine chromosome 1.

Several interferon-activatable murine genes were mapped to murine chromosomes by hybridizing cDNA probes to Southern blots of genomic DNA samples from a panel of mouse-hamster somatic cell hybrid lines. The 12 gene is located on chromosome 12 and it specifies a 3.6-kb mRNA. The 204 gene (specifying a 2.5-kb mRNA), and three genes of the 203 gene family (hybridizing to five mRNAs of sizes between 2 and 4.5 kb), together with the 202 gene (specifying a 2-kb mRNA) are located on murine chromosome 1. By restriction fragment length polymorphism analysis of DNA samples prepared from a panel of recombinant inbred mouse lines (C57BL/6J D DBA/2J) and from 85 [C3H/HeJ-gld/gld x Mus spretus) F1 X C3H/HeJ-gld/gld] backcross mice we established a close linkage of the 202, 203, and 204 genes to the erythroid alpha-spectrin gene (Spna-1) on distal murine chromosome 1. Cosmids containing the 202, 203, and 204 genes were isolated from a library derived from AKR mouse DNA. Southern blot analysis of such cosmids revealed: (a) hybridization of a partial 203 cDNA to three genes of the 203 gene family; (b) cross-hybridization of the 202 and 204 genes with one another and with a third gene (designated as 201 gene), and (c) a close linkage of genes of the 203 family with the 201, 202, and 204 genes. These results indicate the existence of a cluster of at least six closely linked, interferon-activatable genes on distal murine chromosome 1 in the vicinity of the Spna-1 locus and also of the Minor lymphocyte stimulating locus (Mlsa).

Animals↗
PubMed1988

Interferons as gene activators: close linkage of two interferon-activatable murine genes.

Previously we have identified a mouse genomic clone (clone 5) which specifies the 5' flanking region and the 5' terminal exon of an interferon-activatable gene (202 gene). Here, we show that about 5 kb upstream from this flanking region in clone 5 there occurs a 3' terminal region of a second interferon-activatable gene (203 gene). The two genes are transcribed in the same direction. Segments from the 203 gene can be hybridized to a set of five interferon-inducible RNAs. The 203 mRNAs are induced about 15-fold in interferon-treated Ehrlich ascites tumor cells.

Animals↗
PubMed1987

Interferons as gene activators. Characteristics of an interferon-activatable enhancer.

Previously we linked a 0.8-kilobase segment (including the 5'-flanking region and the 5'-terminal exon) of an interferon-activatable mouse gene (202 gene) to the chloramphenicol acetyltransferase gene and transfected the construct into mouse Ltk- cells (Samanta, H., Engel, D. A., Chao, H. M., Thakur, A., Garcia-Blanco, M. A., and Lengyel, P. (1986) J. Biol. Chem. 261, 11849-11858). Treatment of these cells with mouse beta-interferon increased the expression of the chloramphenicol acetyltransferase gene 5-10-fold. Here we demonstrate that this segment from the 202 gene has characteristics of an interferon-activatable enhancer: (a) it can activate a heterologous promoter (SV40 early promoter), (b) it is active in both the appropriate and the inverted orientation and in either upstream or downstream locations from the promoter activated, and (c) treatment of cells with interferon increases its activity severalfold.

Animals↗
PubMedDate not supplied

Nutritional education of CAPD patients and media influence.

The aim of our paper was to investigate the short period of training offered to peritoneal dialysis patients. We focused our attention on the nutritional knowledge of patients who often gather information, and advice from external factors such as their family and the media. We organized group meetings on nutrition for 22 patients and 17 relatives. Questionnaires were completed before and after the education programme. The group meetings improved knowledge on nutrition and highlighted the influence of the media. The important role of the nurse at these meetings has also been recognised.

Adult↗