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J L Olivier

Publications and source records attributed to J L Olivier.

At least 19 recordsLinked to original sources
PubMed2005

Anaphylactic reaction to inulin: first identification of specific IgEs to an inulin protein compound.

BACKGROUND: A woman with a past history of allergy to artichoke presented with two episodes of immediate allergic reactions, one of which was a severe anaphylactic shock after eating two types of health foods containing inulin. RESULTS: Dot blot assay techniques identified specific IgEs to artichoke, to yoghurt F, and to a heated BSA + inulin product. Dot blot inhibition techniques confirmed the anti-inulin specificity of specific IgE. CONCLUSIONS: The absence of a positive reaction to an unheated milk-inulin mixture indicates the probability of protein-inulin binding. There is no cross-reactivity with the carbohydrates of the glycosylated allergens.

Anaphylaxis↗
PubMed2000

Transcriptional regulation of inflammatory secreted phospholipases A(2).

Secreted phospholipases A(2) is a family of small molecular weight and calcium-dependent enzymes of which the members list is presently growing. Among these enzymes, the synovial type IIA and the type V phospholipases A(2) are involved in inflammation. Although their actual mechanism is still a subject of debate, new therapeutic strategies can result from the knowledge of the regulations of their gene expression. The human genes of the type IIA and type V phospholipases A(2) are located on the chromosome 1 at close positions and transcribed in reverse orientations. These genes can therefore be regulated by common elements but only the regulation of the type IIA phospholipase A(2) gene expression has been extensively studied. Pro-inflammatory cytokines upregulate while the growth factors downregulate the type IIA phospholipase A(2) gene expression. Interleukin-6 and interleukin-1beta exert their effects at least partially at the transcriptional level. The transcriptional regulation of the type IIA phospholipase A(2) gene is cell- and species-specific. The activity of the human promoter is controlled by the CAAT-enhancer binding protein (C/EBP) factors while that of the rat promoter is regulated by nuclear factor kappaB (NF-kappaB) and C/EBPs. Furthermore, the human promoter is constitutively repressed in hepatocytes by single strand DNA binding proteins whose effects are relieved by C/EBP factors while the glucocorticoid receptor interacts with C/EBPs in chondrocytes to achieve full basal and interleukin-1beta-stimulated transcription activity. Other factors like CTF/NF1 and Sp1 might be involved in the regulation of both the rat and human promoter. Peroxisome proliferator-activated receptors could contribute to the stimulation of the rat promoter by NF-kappaB in vascular smooth muscle cells. The study of the coactivators and coinhibitors associated to these transcription factors will give a better understanding of the diversity and complexity of the transcriptional regulations of the type IIA phospholipase A(2) gene.

Animals↗
PubMed2000

Induction of secreted type IIA phospholipase A2 gene transcription by interleukin-1beta. Role of C/EBP factors.

Secreted type IIA phospholipase A(2), which is involved in arachidonic acid release, is abundantly produced by chondrocytes and secreted in the synovial fluids of patients affected by rheumatoid arthritis. Transfection experiments showed that interleukin-1beta stimulates the phospholipase A(2) [-1614; +20] promoter activity by 6-7-fold and that the [-210; -176] fragment is critical for this stimulation. CAAT enhancer-binding protein (C/EBP) beta and C/EBPdelta transcription factors bind to this element as shown by bandshift experiments. Interleukin-1beta increased the levels of C/EBPdelta mRNA as soon as 2 h and up to 24 h without affecting those of C/EBPbeta. Higher amounts of C/EBPdelta proteins correlate with the stimulation of C/EBPdelta mRNA. Mutations or 5' deletions in the upstream [-247; -210] region reduced by 2-fold the basal and interleukin-1beta-stimulated transcription activities. Two types of factors bind to overlapping sequences on this fragment: NF1-like proteins and the glucocorticoid receptor. The glucocorticoid receptor is responsible for a moderate stimulation of the promoter activity by dexamethasone and may interact with C/EBP factors to achieve a full transcription activity in basal conditions and in the presence of interleukin-1beta. A [-114; -85] proximal regulatory element forms three complexes in bandshift experiments, the slowest mobility one involving the Sp1 zinc finger factor. Mutation of this sequence reduced to 2-fold the stimulation of the promoter activity by interleukin-1beta or the C/EBP factors. Induction of the transcription of secreted type IIA phospholipase A(2) gene by interleukin-1beta in chondrocytes absolutely requires C/EBPbeta and C/EBPdelta factors but does not involve NF-kappaB.

Animals↗
PubMed2000

Critical role of C/EBPdelta and C/EBPbeta factors in the stimulation of the cyclooxygenase-2 gene transcription by interleukin-1beta in articular chondrocytes.

The activity of the [-831; +103] promoter of the human cyclooxygenase-2 gene in cultured rabbit chondrocytes is stimulated 2.9 +/- 0.3-fold by interleukin-1beta and this stimulation depends on [-132; -124] C/EBP binding-and [-223; -214] NF-kappaB binding-sites. The C/EBPbeta and C/EBPdelta factors bind to the [-132; -124] sequence. The [-61; -53] sequence is also recognized by C/EBPbeta and C/EBPdelta as well as USF. Mutation of the whole [-61; -53] sequence abolished the stimulation of transcription but single mutations of the C/EBP or USF site did not alter the activity of the promoter, suggesting that the factors bound to the proximal [-61; -53] sequence interact with different members of the general transcription machinery. The [-223; -214] site binds only the p50/p50 homodimer and a non-rel-related protein, but not the transcriptionally active heterodimer p50/p65. The p50/p50 homodimer could interact with the C/EBP family members bound to the [-132; -124] sequence for full stimulation of the COX-2 transcription by interleukin-1beta in chondrocytes. By contrast, the [-448; -449] sequence binds with a low affinity both the p50/p50 homodimeric and p50/p65 heterodimeric forms of NF-kappaB but has no role in the regulation of the human COX-2 promoter in chondrocytes.

Animals↗
PubMed1999

N-terminal and C-terminal plasma membrane anchoring modulate differently agonist-induced activation of cytosolic phospholipase A2.

The 85 kDa cytosolic phospholipase A2 (cPLA2) plays a key role in liberating arachidonic acid from the sn-2 position of membrane phospholipids. When activated by extracellular stimuli, cPLA2 undergoes calcium-dependent translocation from cytosol to membrane sites which are still a matter of debate. In order to evaluate the effect of plasma membrane association on cPLA2 activation, we constructed chimeras of cPLA2 constitutively targeted to the plasma membrane by the N-terminal targeting sequence of the protein tyrosine kinase Lck (Lck-cPLA2) or the C-terminal targeting signal of K-Ras4B (cPLA2-Ras). Constitutive expression of these chimeras in Chinese hamster ovary cells overproducing the alpha2B adrenergic receptor (CHO-2B cells) did not affect the basal release of [3H]arachidonic acid, indicating that constitutive association of cPLA2 with cellular membranes did not ensure the hydrolysis of membrane phospholipids. However, Lck-cPLA2 increased [3H]arachidonic acid release in response to receptor stimulation and to increased intracellular calcium, whereas cPLA2-Ras inhibited it, compared with parental CHO-2B cells and CHO-2B cells producing comparable amounts of recombinant wild-type cPLA2. The lack of stimulation of cPLA2-Ras was not due to a decreased enzymatic activity as measured using an exogenous substrate, or to a decreased phosphorylation of the protein. These results show that the plasma membrane is a suitable site for cPLA2 activation when orientated correctly.

Amino Acid Sequence↗
PubMed1998

An SP1-like 5'-GACCACGCC-3' sequence is critical for activity of the inflammatory phospholipase A2 promoter and binds several non-zinc finger proteins.

We have previously shown that the promoter of the type IIa secreted phospholipase A2 gene contains a strong positive regulatory proximal element [-125 to -85] element B. Mutation of this element abolishes the activation of the phospholipase A2 promoter by C/EBPbeta in HepG2 cells. Liver nuclear proteins form three major and two minor complexes with this element. The [-107 to -99] 5'-GACCACGCC-3' sequence is critical for the formation of these complexes and the activity of the promoter. Although the sequence of element B is highly similar to those of Sp1 binding sites, it does not bind Sp1 or other zinc-finger proteins. Each major complex contains a single protein, the molecular masses of these proteins being 100, 90 and 75 kDa. These proteins have the same nucleotide requirements for binding, with the cytosines at positions -102, -100, -99 and the adenosine at -103 being the most important nucleotides. The activity of the phospholipase A2 promoter in HeLa cells was lower than in HepG2 cells, and was correlated with the absence of complex 3 in HeLa cell nuclear extracts. Our results suggest different roles for the proteins bound to the 5'-GACCACGCC-3' sequence. In particular, the 75-kDa protein which forms the third complex is critical for the activity of the promoter of the secretory phospholipase A2 gene.

Animals↗
PubMed1998

Detection and quantification of the A3243G mutation of mitochondrial DNA by ligation detection reaction.

The A3243G mutation of mitochondrial DNA is associated to the MELAS syndrome and to transmitted forms of diabetes mellitus. This mutation exists in a heteroplasmic state and can be present at a minor and hardly detectable level. The aim was to design a method which could be applied to large series of samples and could provide rapid, sensitive and quantitative detection of this mutation in the wild-type mitochondrial DNA background. The ability of ligation detection reaction (LDR) to satisfy these objectives was evaluated. Ligation detection reaction was performed on a model template composed of mixtures of various proportions of plasmids bearing the wild-type or mutant mitochondrial DNA sequence. Radiolabelled or fluorescent primers and the wild-type and mutant LDR products were separated by electrophoresis on conventional denaturating gel or on an Applied Biosystem 373. The ratios of mutant/wild-type products were consistent with the initial ratios of the plasmids in the template. The sensitivity and accuracy of the fluorescence and isotopic detection methods were similar. The detection limit of mutant DNA was 10% of total mitochondrial DNA. The percentage of mutant DNA in DNA samples extracted from leukocytes of 19 patients having the mutation at different levels, was evaluated by fluorescent or isotopic LDR.

Base Sequence↗
PubMed1997

Posttranscriptional effect of insulin-like growth factor-I on interleukin-1beta-induced type II-secreted phospholipase A2 gene expression in rabbit articular chondrocytes.

Large amounts of type II-secreted phospholipase A2 (type II sPLA2) are secreted into inflammatory synovial fluid and they are believed to induce the synthesis of lipid mediators by articular chondrocytes. Preliminary experiments showed that insulin-like growth factor-I, which counteracts cartilage degradation in arthritis, inhibits interleukin-1beta-induced type II sPLA2 gene expression in rabbit articular chondrocytes (Berenbaum, F., G. Thomas, S. Poiraudeau, G. Bereziat, M.T. Corvol, and J. Masliah. 1994. FEBS Lett. 340: 51-55). The present study showed that IL-1beta induced the sustained synthesis of prostaglandin E2 and a parallel increase in type II sPLA2 gene expression (assessed by enzymatic activity and Northern blot analysis), but no increase in cytosolic PLA2 gene expression (assessed by Northern and Western blot analysis) or cytosolic PLA2 activity in rabbit articular chondrocytes. IGF-I inhibited both IL-1beta-stimulated PGE2 synthesis and type II sPLA2 gene expression, but had no effect on cytosolic PLA2 gene expression. Nuclear run-on experiments revealed that IL-1beta stimulated the transcription rate of type II sPLA2 gene, giving rise to long-lived mRNA in cells treated with actinomycin D. IGF-I did not affect transcription rate, suggesting that it acts as a post-transcriptional step. Sucrose density gradient analysis of the translation step showed no effect of IGF-I on the entry of type II sPLA2 mRNA into the polysomal pool or on its distribution into the various polysomal complexes, suggesting that IGF-I does not act on the translation of the mRNA. Lastly, IGF-I strongly decreased the half-life of IL-1beta-induced type II sPLA2 mRNA (from 92 to 12 h), suggesting that IGF-I destabilizes mRNA. These data demonstrate that IL-1beta stimulates the transcription rate of the type II sPLA2 gene and gives rise to a very stable mRNA. In contrast, IGF-I decreases the half-life of the type II sPLA2 message.

Amino Acid Sequence↗
PubMed1997

C/EBP factor suppression of inhibition of type II secreted phospholipase A2 promoter in HepG2 cells: possible role of single-strand binding proteins.

We previously reported that the type II secreted phospholipase A2 (sPLA2) promoter from positions (-326 to +20) ([-326;+20] promoter) is negatively regulated by two adjacent regulatory elements, C (-210 to -176) and D (-247 to -210). This study examines in greater detail the way in which this negative regulation operates. Successive 5' deletions of the [-326;+20] type II sPLA2 promoter indicated that the region upstream of position -195 inhibits the transcription activity sixfold in HepG2 cells but not in HeLa cells. Although the whole [-326;-176] region decreased the activity of a heterologous thymidine kinase promoter, this effect was orientation and position sensitive. C/EBP beta, C/EBP alpha, and C/EBP delta, which bind to element C, prevented the inhibition of promoter activity. Electrophoretic mobility shift experiments identified the binding of NF1-like proteins to the [-225;-218] site, which overlaps an insulin response-like sequence, 5'-TGTTTTG-3'. This sequence bound a factor which also recognized the promoters of the apolipoproteins C-III and A-II. Substitutions preventing the binding of this factor or the NF1-like proteins did not increase the transcription activity, but substitution in the [-217;-204] sequence blocked the transcription inhibition. This sequence did not bind any double-strand binding factor, but its antisense strand is critical for the binding of single-strand binding proteins to the [-232;-191] region. We therefore suggest that these single-strand binding proteins are involved in the inhibitory mechanism.

Animals↗
PubMed1997

Differential stimulation of cytosolic phospholipase A2 by bradykinin in human cystic fibrosis cell lines.

Tracheal epithelial cells and skin fibroblasts from different cystic fibrosis (CF) patients bearing the deltaF508 mutation of cystic fibrosis transmembrane conductance regulator (CFTR) released more arachidonic acid in response to bradykinin than do other CF and normal cells. Immortalized tracheal epithelial cell lines were used as models to study the mechanisms of this dysregulation. An 85 kD cytosolic phospholipase A2 (cPLA2) was found in these cells and bradykinin increased its binding to membranes of deltaF508 cells (CFT-2) but not to those of a double heterozygous CF cells (CFT-1), or of control cells (NT-1). The expression of G alpha(q)/11 protein was also increased in deltaF508 cells, with increased stimulation of phosphatidylinositol diphosphate-specific phospholipase C (PLC) by bradykinin, and an early, transient activation of mitogen-activated protein (MAP) kinase. As the binding of cPLA2 to membranes is Ca2+-dependent, the increased coupling to PLC could cause the hypersensitivity to bradykinin. Comparison of the effects of bradykinin to those observed with thapsigargin, an inhibitor of calcium reuptake, suggests that the increase of intracellular calcium is not the only mechanism involved in arachidonic acid release by bradykinin in deltaF508 cells. The lack of effect of calcium ionophore A23187 or TPA on arachidonic acid release from any of the cell lines suggested that activation needs a PKC-independent cPLA2 phosphorylation step, perhaps via MAP kinase activation. The binding of cPLA2 to membranes after bradykinin stimulation still occurred in CFT2 cells (deltaF508) homogenized in EDTA, suggesting that a membrane component plus increased intracellular calcium influenced cPLA2 anchoring to membranes. The defective processing of deltaF508 CFTR seems to increase cPLA2 stimulation by bradykinin, since the bradykinin-stimulated release of arachidonic acid is reversed by growing cells at 28 degrees C for 48 h. The deltaF508 mutation of CFTR appears to increase the stimulation of cPLA2 by Gq-mediated receptors in a PKC-independent and MAP kinase-dependent manner. Hence normal CFTR, or normally processed deltaF508 CFTR, inhibit cPLA2 stimulation. The greater reactivity of deltaF508 CFTR cells to inflammatory mediators might be part of the increased sensitivity of CF patients to lung inflammation.

Bradykinin↗
PubMed1995

Pulmonary toxoplasmosis in HIV-infected patients: usefulness of polymerase chain reaction and cell culture.

Toxoplasmosis is a serious opportunistic infection in patients with acquired immunodeficiency syndrome (AIDS). The lung is a major site of infection after the central nervous system. The aim of the study was to assess the polymerase chain reaction (PCR) and cell culture for the detection of Toxoplasma gondii. One hundred and thirty two human immunodeficiency virus (HIV)-infected patients with respiratory manifestations, who underwent fibreoptic bronchoalveolar lavage, were investigated. Detection of Toxoplasma gondii was compared using three techniques: Giemsa staining; polymerase chain reaction with specific primers derived from the P30 gene; and culture on the MRC5 cell line. Toxoplasma gondii was detected in the same four samples by all three techniques. We conclude that PCR adds little to conventional (and cheaper) tools already used to diagnose pulmonary toxoplasmosis.

AIDS-Related Opportunistic Infections↗
PubMed1994

Positive and negative hepatic regulation of the human type II phospholipase A2 gene.

To identify the elements which regulate the liver transcription of the human type II phospholipase A2 gene and its stimulation by interleukin 6, the 5' flanking region from -1614 to +806 and several 3' and 5' deleted fragments have been analyzed in CAT assays. Negative regulatory elements have been located in the regions -1614 to -326 and +20 to +806. The fragment -326 to +20 contains the main elements required for the transcription as well as for the stimulation by interleukin 6. Footprinting assays have been performed on this region and showed four protected elements, A [-35;-6], B [-125;-86], C [-209;-176], and D [-247;-211]. Deletion of element D enhanced the transcription of the reporter gene 10.5-fold compared to the [-326;+20]-CAT construct. Further deletions up to position -87 which removed both the elements B and C or the substitution of element C by a nonspecific sequence lowered the promoter activity to 23% and 70% of the control, respectively. These results indicate that element C binds positive regulatory factors and element D binds a negative regulatory factor. Furthermore, stimulation by interleukin 6 is lost when element C is substituted or deleted. As shown by the footprinting and band shift assays, the transcription factors C/EBP alpha and C/EBP beta can bind to elements C and D but the dissociation constant (Kd) of C/EBP alpha is 10 times lower for element C (0.6 nM) than for element D (5.8 nM). Band shift experiments using rat liver nuclear extracts showed that element C formed four heat stable complexes, some of which could be supershifted by anti C/EBP alpha antibodies. The binding of C/EBP factors to element C was confirmed by competition with previously described oligonucleotide and nucleotide substitution of element C. Band shift experiments using rat liver nuclear extracts showed that element D formed one major DNA-protein complex. This complex could be competed out by oligonucleotides containing a cAMP responsive element (CRE) but not by oligonucleotides containing the binding site of C/EBP. However, anti-CREB antibodies did not supershift this complex. Methylation interference experiments showed the involvement of a G nucleotide upstream to the sequence homologous to CRE in the binding of the hepatic nuclear factors.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

Usefulness of PCR for detection of Pneumocystis carinii DNA.

Diagnosis of Pneumocystis carinii pneumonia is based on the identification of the various stages of the parasite in lung samples by standard staining techniques. We therefore assessed the value of the PCR for detection of P. carinii in bronchoalveolar lavage, induced sputum, and blood samples relative to that of standard staining techniques.

AIDS-Related Opportunistic Infections↗
PubMed1991

Type II phospholipase A2 recombinant overexpression enhances stimulated arachidonic acid release.

The coding sequence of type II phospholipase A2 from human placenta was cloned in a bovine papilloma virus-derived eukaryotic expression vector under the control of the metallothionein promoter. Stably transfected C127 mouse fibroblast lines were obtained with this vector. These transfected cells overexpressed a functional 14 kDa phospholipase A2, which was bulky secreted. However, a significant phospholipase A2 activity was measured in cell homogenates. The involvement of this 14 kDa phospholipase A2 in mechanisms related to stimulated arachidonic acid release was investigated. We could parallel the overexpression of phospholipase A2 with an increase in phorbol ester and fluoroaluminate-stimulated arachidonic acid release. Pertussis toxin inhibited this stimulation. These results suggest that the 14 kDa type II phospholipase A2 might contribute to stimulation of arachidonic acid release, and therefore to eicosanoid production.

Animals↗
PubMed1991

Detection and typing of human papillomaviruses in cervical smears by an original application of the polymerase chain reaction.

The detection and typing of human papillomaviruses on cervical smears were performed by means of a new application of the polymerase chain reaction allowing easier and faster detection of the amplification product. This application consisted of a combination of two series of amplifications and the use of primers labelled with biotin and with 125 iodine on a reporter group for the second amplification. The final amplification product was detected by counting the radioactivity after incubation of the media in avidin-coated tubes. This test was compared with conventional methods of detection by electrophoresis and Southern blot and its specificity was confirmed. The study of a series of 52 patients demonstrated a higher prevalence of type 16 in relation to type 6/11 and 18 and a correlation between the degree of dysplasia and the frequency of oncogenic types 16 and 18. This new application could facilitate studies of the prevalence of HPV in large series of cervical smears.

Avidin↗
PubMed1991

[Cellular phospholipases A2, structure-function relationship].

Two PLA2 are involved in cell signaling and in phospholipid homeostasis in mammalian cells. The first one is a 14 kDa protein whose cDNA was cloned in 1989. This enzyme exhibits a strong homology with pancreatic PLA2 but is more related to type II PLA2. This PLA2 is secreted by different tissues in response to inflammatory processes. Their main function seems to be the hydrolysis of membranes of altered cells or of bacteria and the stimulation of lipid mediator synthesis. The first cDNA of an another important PLA2 group was cloned in 1991. The protein deduced is a 88 kDa cytoplasmic protein. It is involved in cell signaling by stimulating the production of free fatty acids and of their oxygenated products. These products might in turn either activate transducing proteins or stimulate membrane receptors.

Cytoplasm↗
PubMed1990

Phospholipid synthesis by extracellular phospholipase A2 in organic solvents.

The catalytic activity of extracellular phospholipase A2 was studied in low polarity solvents where hydrolytic enzymes have been demonstrated to catalyze synthesis reactions. It was demonstrated that extracellular phospholipase A2 can catalyze the esterification of lysophosphatidylcholine with oleic acid. Up to 6.5% of lysophosphatidylcholine can be esterified into phosphatidylcholine. This activity requires a preincubation of the enzyme in a pH 9 aqueous solution containing calcium, before the incubation in the non-aqueous solvent. No transfer of fatty acid between a phospholipid and a lysophospholipid or between two phospholipids was observed. These results may be useful in understanding the function of the membrane phospholipase A2 which may catalyze acylation or deacylation depending on the local physico-chemical environment.

Calcium↗