Biomedical subjects

F Russo-Marie

Publications and source records attributed to F Russo-Marie.

At least 19 recordsLinked to original sources

PubMed2000

Increased apoptosis in U937 cells over-expressing lipocortin 1 (annexin I).

The potential involvement of endogenous lipocortin 1 in the process of cellular apoptosis, particularly in cells of the myelo-monocytic lineage, has been investigated. U937 cells were transfected either with an antisense or a sense DNA for lipocortin 1 and the stable clones 36.4AS clone (20-40% lower lipocortin 1 levels) and 15S (30% higher lipocortin 1 levels) were obtained. Cell apoptosis was induced by incubation with tumor necrosis factor-alpha: optimal responses were observed within a 24 h incubation period at a 5 ng/ml concentration. Apoptosis was assessed both morphologically, by annexin V binding and cell cycle analysis with propidium iodide. Whilst no consistent difference was seen between wild type cells and clone 36.4AS, a higher incidence of apoptosis (ranging from +30% to + 60%) was observed in the 15S clone. Release of arachidonic acid from loaded cells was promoted by 24 h incubation with the cytokine, and a higher degree of release was measured in the 15S clone. These data indicate that endogenous intracellular lipocortin 1 is involved in the promotion of apoptosis in cells of the myelo-monocytic derivation.

Annexin A1↗

PubMed2000

Structural basis of the Ca(2+)-dependent association between S100C (S100A11) and its target, the N-terminal part of annexin I.

BACKGROUND: S100C (S100A11) is a member of the S100 calcium-binding protein family, the function of which is not yet entirely clear, but may include cytoskeleton assembly and dynamics. S100 proteins consist of two EF-hand calcium-binding motifs, connected by a flexible loop. Like several other members of the family, S100C forms a homodimer. A number of S100 proteins form complexes with annexins, another family of calcium-binding proteins that also bind to phospholipids. Structural studies have been undertaken to understand the basis of these interactions. RESULTS: We have solved the crystal structure of a complex of calcium-loaded S100C with a synthetic peptide that corresponds to the first 14 residues of the annexin I N terminus at 2.3 A resolution. We find a stoichiometry of one peptide per S100C monomer, the entire complex structure consisting of two peptides per S100C dimer. Each peptide, however, interacts with both monomers of the S100C dimer. The two S100C molecules of the dimer are linked by a disulphide bridge. The structure is surprisingly close to that of the p11-annexin II N-terminal peptide complex solved previously. We have performed competition experiments to try to understand the specificity of the S100-annexin interaction. CONCLUSIONS: By solving the structure of a second annexin N terminus-S100 protein complex, we confirmed a novel mode of interaction of S100 proteins with their target peptides; there is a one-to-one stoichiometry, where the dimeric structure of the S100 protein is, nevertheless, essential for complex formation. Our structure can provide a model for a Ca(2+)-regulated annexin I-S100C heterotetramer, possibly involved in crosslinking membrane surfaces or organising membranes during certain fusion events.

Acetylation↗

PubMed2000

System A neutral amino acid transporter regulation by interleukin-1beta in human osteoarthritic synovial cells: evidence for involvement of prostaglandin E(2) as a second messenger.

We studied the long-terms effects of interleukin-1beta (IL-1beta; 3 to 6 h) on alpha-(methylamino) isobutyric acid (MeAIB), a nonmetabolizable amino acid transported by system A. We found that IL-1beta induced a large decrease in MeAIB uptake by human osteoarthritic synovial cells and a concomitant increase in prostaglandin E(2) (PGE(2)) synthesis. Therefore, we investigated whether PGE(2) acts as a mediator for the long-term action of IL-1beta. We found that exogenous PGE(2) inhibited MeAIB uptake, and that AH6809, a PGE(2) receptor antagonist, inhibited IL-1beta-mediated MeAIB uptake. To identify the enzymes involved in the IL-1beta-mediated synthesis of PGE(2) that inhibits MeAIB uptake, we studied the expression of secreted (s) and cytosolic (c) phospholipase A(2) (PLA(2)). Because both were expressed, we selected a broad spectrum of inhibitors to determine which of the two PLA(2)s was involved. We used AACOCF3, a cPLA(2) inhibitor, and dithiothreitol (DTT) and bromophenacyl bromide (BPB), which are sPLA(2) inhibitors. Our results suggest that the PLA(2) involved in the IL-1beta-mediated synthesis of PGE(2) was sPLA(2). We also showed the expression of cyclooxygenase (COX)-2 and its partial involvement using a potent selective COX-2 inhibitor, L-745337. These findings provide insight into the mechanisms underlying the IL-1beta-mediated regulation of transport system A. The Il-1beta-induced inhibition of MeAIB uptake in human osteoarthritic synovial cells thus seems to be essentially mediated by PGE(2) production via the activation of sPLA(2) and the partial activation of COX-2.

Amino Acid Transport Systems↗

PubMed2000

Annexin 1 expression and phosphorylation are upregulated during liver regeneration and transformation in antithrombin III SV40 T large antigen transgenic mice.

We have used a transgenic animal model, which constitutively develops hepatocarcinoma (Antithrombin III SV40 T large Antigen: ASV), to study the involvement of Annexin 1 (ANX1) in liver regeneration and malignant transformation. Primary hepatocytes isolated from normal mice did not express ANX1. In contrast, ANX1 was strongly expressed in hepatocytes of transgenic mice during constitutive development of hepatocarcinoma. In ASV transgenic mice, an elevated ANX1 level preceded the appearance of the tumor, indicating that it could be a good marker in the diagnosis of cancer. One-third hepatectomy in normal mice resulted in stimulation of ANX1 synthesis and phosphorylation. This upregulation correlated with increased synthesis of EGF and consequently with increased phosphorylation of the EGF receptor (EGF-R). Stable transfection of a hepatocyte cell line derived from ASV transgenic mice (mhAT2) with antisense complementary DNA for ANX1 reduced the proliferation rate as well as cytosolic phospholipase A(2) (cPLA(2)) activity. Thus, ANX1 expression and phosphorylation could be a factor implicated in liver regeneration and tumorigenesis, either through modulation of cPLA(2) activity or EGF-R function.

Animals↗

PubMed2000

Expression and localization of the annexins II, V, and VI in myocardium from patients with end-stage heart failure.

Annexins II, V, and VI belong to a family of Ca(2+)-dependent phospholipid-binding proteins that have been involved mainly in signal transduction, differentiation, membrane trafficking events, or binding to the extracellular matrix, or that might be effective as Ca(2+)-channels. They are abundant in the mammalian myocardium and might play a role in ventricular remodeling and altered calcium handling during heart failure. To test this hypothesis, we compared the expression and distribution of these annexins in nonfailing (n = 9) and failing human hearts with idiopathic dilated cardiomyopathy (n = 11). Northern blot and slot blot analysis were used to determine the annexin mRNA levels and Western blots were used to quantify the amounts of annexin proteins. Distribution of annexins was studied by immunohistofluorescence labeling and compared with that of a sarcolemmal marker (Na+/K(+)-ATPase) and of a myofibrillar protein (alpha-actinin). We showed that nonfailing hearts contained a higher amount of annexin VI than of annexin V or II (13.5 +/- 1.8, 3.7 +/- 0.2, and 2.5 +/- 0.5 microg/mg protein, respectively). In failing hearts, there was a parallel increase in both mRNA and protein levels of annexin II (146% and 132%, p < 0.05, respectively) and annexin V (152%, p < 0.01, 147%, p < 0.005, respectively); the protein level of annexin VI was also increased (117%, p < 0.05), whereas the increase of its mRNA level was statistically insignificant. We observed a predominant localization of annexin II in interstitium, and of annexins V and VI in cardiomyocytes at the level of the sarcolemma, T-tubules, and intercalated disks in nonfailing hearts, whereas in failing hearts enlarged interstitium contained all three annexins. Furthermore, annexin V staining at the level of cardiomyocytes almost disappeared. In conclusion, we showed that heart failure is accompanied by marked overexpression of annexins II and V, as well as translocation of annexin V from cardiomyocytes to interstitial tissue. The data suggest that annexins may contribute to ventricular remodeling and annexin V to impaired Ca2+ handling in failing heart.

Annexin A2↗

PubMed1999

Annexin V counteracts apoptosis while inducing Ca(2+) influx in human lymphocytic T cells.

We have previously shown that when annexin V is present during the execution of a cell death program, apoptosis is delayed. This is reflected by the inhibition of DNA cleavage and of the release of apoptotic membrane particles, and by reduction of the proteolytic processing of caspase-3. Here, we have studied the mechanism(s) through which annexin V counteracts apoptosis in the human CEM T cell line. The degree of apoptosis inhibition was associated with an increase of intracellular Ca(2+) concentration ([Ca(2+)](i)). Reduction of the extracellular Ca(2+) concentration by EGTA abolished the anti-apoptotic effect, suggesting that annexin V favors Ca(2+) influx and that Ca(2+) acts as an inhibitor rather than an activator of apoptosis in CEM T cells. The effects on apoptosis and [Ca(2+)](i) of several modified annexins with different electrophysiological properties indicate that the N-terminal domain of annexin V is necessary for the Ca(2+)-dependent anti-apoptotic action of annexin V. These results suggest that annexin V regulates membrane Ca(2+) permeability and is protective against apoptosis by increasing [Ca(2+)](i) in CEM T cells.

Annexin A1↗

PubMed1999

Anti-inflammatory mechanism of alminoprofen: action on the phospholipid metabolism pathway.

Alminoprofen is a nonsteroidal anti-inflammatory drug (NSAID) of the phenylpropionic acid class. It has anti-inflammatory properties different from the classical NSAID. Using both in vitro systems of cells in culture and in vivo models of inflammation, we report here that alminoprofen possesses both antiphospholipase A2 (PLA2) activity and anti-cycloxygenase (COX) activity. The PLA2 targeted by alminoprofen is likely the secretory phospholipase A2 (sPLA2) while the COX targeted is the COX-2.

Animals↗

PubMed1999

The crystal structure of a complex of p11 with the annexin II N-terminal peptide.

The aggregation and membrane fusion properties of annexin II are modulated by the association with a regulatory light chain called p11.p11 is a member of the S100 EF-hand protein family, which is unique in having lost its calcium-binding properties. We report the first structure of a complex between p11 and its cognate peptide, the N-terminus of annexin II, as well as that of p11 alone. The basic unit for p11 is a tight, non-covalent dimer. In the complex, each annexin II peptide forms hydrophobic interactions with both p11 monomers, thus providing a structural basis for high affinity interactions between an S100 protein and its target sequence. Finally, p11 forms a disulfide-linked tetramer in both types of crystals thus suggesting a model for an oxidized form of other S100 proteins that have been found in the extracellular milieu.

Animals↗

PubMed1999

Localization and quantitation of cardiac annexins II, V, and VI in hypertensive guinea pigs.

Annexins are characterized by Ca2+-dependent binding to phospholipids. Annexin II mainly participates in cell-cell adhesion and signal transduction, whereas annexins V and VI also seem to regulate intracellular calcium cycling. Their abundance and localization were determined in left ventricle (LV) and right ventricle (RV) from hypertensive guinea pigs, during the transition from compensatory hypertrophy to heart failure. Immunoblot analysis of annexins II, V, and VI revealed an increased accumulation (2.6-, 1.45-, and 2.3-fold, respectively) in LV from hypertensive guinea pigs and no modification in RV. Immunofluorescent labeling of annexins II, V, and VI; of Na+-K+-ATPase; and of sarcomeric alpha-actinin showed that in control LV and RV, 1) annexin II is present in nonmuscle cells; 2) annexins V and VI are mainly observed in the sarcolemma and intercalated disks of myocytes; 3) annexins II, V, and VI strongly label endothelial cells and adventitia of coronary arteries; and 4) annexin VI is present in the media. At the onset of heart failure, the most striking changes are the increased protein accumulation in LV and the very strong labeling of annexins II, V, and VI in interstitial tissue, suggesting a role in fibrosis development and cardiac remodeling.

Animals↗

PubMed1999

Annexin V and phospholipid metabolism.

Annexins, protein kinases C and cytosolic phospholipase A2 belong to three families of ubiquitous cytoplasmic proteins involved in signal transduction. All annexins share the property of binding to phospholipids in the presence of calcium. Most annexins are substrates for protein kinases C except annexin V, the most ubiquitous and abundant annexin. Protein kinases C (PKC) belong to three distinct groups of kinases, conventional PKCs (cPKCs) that depend on calcium, diacylglycerol and negatively charged phospholipids for their activity, novel PKCs (nPKCs) and atypical PKCs (aPKCs), that do not require calcium for their activity, although they both require negatively charged phospholipids. Cytosolic phospholipase A2 (cPLA2) depends on calcium for its catalytic activity as well as on serine phosphorylation by MAP kinases. We report that annexin V modulates the activity of cPKCs as well as of cPLA2 by interfering with their ability to bind to negatively charged phospholipids and calcium. We propose that annexin V could interfere with the calcium and phospholipid signalling pathway.

Animals↗

PubMed1999

[Glucocorticoids and acute phase proteins].

Glucocorticoids as well as acute phase proteins participate in non-specific host defence as well as in restoring host integrity after injury. Plasma levels of both compounds augment during the inflammatory reaction. However, glucocorticoids also have physiological effects that share similar molecular mechanisms with the family of steroids. During the inflammatory reaction, and for participating in host defense, glucocorticoids, together with augmented cytokines, use new signalling pathways. In doing so, they participate in the positive or negative control of inflammatory mediator synthesis. For example, they induce the synthesis of acute phase proteins in synergy with interleukin 6, interleukin 1 and TNF alpha.

Acute-Phase Proteins↗

PubMed1998

Promoting detachment of neutrophils adherent to murine postcapillary venules to control inflammation: effect of lipocortin 1.

In this study we investigated, using intravital microscopy, how neutrophil extravasation across mouse mesenteric postcapillary venules is inhibited by the glucocorticoid-regulated protein lipocortin (LC; also termed annexin) 1. Intraperitoneal injection of 1 mg of zymosan into mice induced neutrophil rolling on the activated mesenteric endothelium followed by adhesion (maximal at 2 hr: 5-6 cells per 100-micrometers of vessel length) and emigration (maximal at 4 hr: 8-10 cells per high-powered field). Treatment of mice with human recombinant LC1 (2 mg/kg s.c.) or its mimetic peptide Ac2-26 (13 mg/kg s.c.) did not modify cell rolling but markedly reduced (>/=50%) the degree of neutrophil adhesion and emigration (P < 0.05). Intravenous treatment with peptide Ac2-26 (13 mg/kg) or recombinant human LC1 (0.7-2 mg/kg) promoted detachment of neutrophils adherent to the endothelium 2 hr after zymosan administration, with adherent cells detaching within 4.12 +/- 0.75 min and 2.36 +/- 0.31 min, respectively (n = 20-25 cells). Recruitment of newly adherent cells to the endothelium was unaffected. The structurally related protein LC5 was inactive in this assay, whereas a chimeric molecule constructed from the N terminus of LC1 (49 aa) attached to the core region of LC5 produced cell detachment with kinetics similar to LC1. Removal of adherent neutrophils from activated postcapillary endothelium is a novel pharmacological action, and it is at this site where LC1 and its mimetics operate to down-regulate this aspect of the host inflammatory response.

Amino Acid Sequence↗

PubMed1998

Exploring the folding pathways of annexin I, a multidomain protein. II. Hierarchy in domain folding propensities may govern the folding process.

In the context of exploring the relationship between sequence and folding pathways, the multi-domain proteins of the annexin family constitute very attractive models. They are constituted of four approximately 70-residue domains, named D1 to D4, with identical topologies but only limited sequence homology of approximately 30%. The domains are organized in a pseudochiral circular arrangement. Here, we report on the folding propensity of the D1 domain of annexin I obtained from overexpression in Escherichia coli. Unlike the D2 domain, which is only partially folded, the isolated D1 domain exhibits autonomous refolding in pure aqueous solution. Similarly, the D3 domain and D2-D3 module were obtained from expression in E. coli but were found to be largely unfolded. No conclusion could be drawn for the D4 domain because it was not possible to extract it from the bacterial inclusion bodies. The data allow us to propose a plausible scenario for the annexin I folding. This working model states that firstly the D1 domain folds, and the D2 and D3 domains remain partly unfolded, facilitating the docking of the D4 domain to the D1 domain. In a second step, the D1 and D4 domains dock, and D4 may fold if already not folded. The final step starts with the stabilization of the D1-D4 module. This stabilization is crucial for allowing the non-native local interactions inside the still partially unfolded D2 domain to switch to the native long-range interactions involving D4. This switch allows the complete folding of D2 and D3. The model proposes a sequential and hierarchical process for the folding of annexin I and emphasizes the role of both native framework and non-native structures in the process.

Annexin A1↗

PubMed1998

Exploring the folding pathways of annexin I, a multidomain protein. I. non-native structures stabilize the partially folded state of the isolated domain 2 of annexin I.

Proteins of the annexin family constitute very attractive models because of their four approximately 70 residue domains, D1 to D4, exhibiting an identical topology comprising five helix segments with only a limited sequence homology of approximately 30%. We focus on the isolated D2 domain, which is only partially folded. A detailed analysis of this equilibrium partially folded state in aqueous solution and micellar solution using 15N-1H multidimensional NMR is presented. Comparison of the residual structure of the entire domain with that of shorter fragments indicates the presence of long-range transient hydrophobic interactions that slightly stabilize the secondary structure elements. The unfolded domain tends to behave as a four-helix, rather than as a five-helix domain. The ensemble of residual structures comprises: (i) a set of native structures consisting of three regions with large helix populations, in rather sharp correspondence with A, B and E helices, and a small helix population in the second part of the C helix; (ii) a set of non-native local structures corresponding to turn-like structures stabilized by several side-chain to side-chain interactions and helix-disruptive side-chains to backbone interactions. Remarkably, residues involved in these local non-native interactions are also involved, in the native structure, in structurally important non-local interactions. During the folding process of annexin I, the local non-native interactions have to switch to native long-range interactions. This structural switch reveals the existence of a sequence-encoded regulation of the folding pathways and kinetics, and emphasizes the key role of the non-native local structures in this regulation.

Annexin A1↗

PubMed1998

In adrenocortical tissue, annexins II and VI are attached to clathrin coated vesicles in a calcium-independent manner.

We have previously characterized three populations of clathrin coated vesicles (CCVs) isolated from bovine adrenocortical tissue and designated them as large, medium and small coated vesicles, i.e., LCV, MCV and SCV, respectively. Here, we show that annexins II and VI, two of the annexins involved in membrane traffic, are present in the three populations of CCVs but with different distributions between coat proteins (CP) and lipidic vesicle membrane. Annexin VI is only associated with the membrane, whatever the CCV population. In contrast, annexin II is differently distributed between coat and membrane, depending on the CCV population. Both annexins are bound to membranes in a calcium-independent manner and solubilization studies in Triton X114 (TX114) suggest that they interact poorly with lipids by hydrophobic interactions. Ligand blotting experiments show that both annexins bind to CCV proteins: annexin II to a 200-kDa component in all CCVs and annexin VI to a 100-kDa component in LCV and SCV identified as dynamin, a GTPase essential for endocytic CCV pinching off. Dynamin is tightly associated to annexin VI only in LCVs, the endocytic [transferrin (Tf) positive] vesicles. Our data suggest that annexins II and VI could define specific protein-lipid interaction microdomains that could play a role in the different functions of the CCVs.

Adrenal Cortex↗

PubMed1998

Annexin V inhibits protein kinase C activity via a mechanism of phospholipid sequestration.

In this study, we assessed the role of annexin V, a Ca2+-dependent phospholipid-binding protein, as a regulator of protein kinase C (PKC) and characterized its mechanism of inhibition. Several mutants obtained by oligonucleotide site-directed mutagenesis were tested in vitro on PKC activity in cytosolic fractions from Jurkat cells and on purified PKCalpha. Annexin V inhibited phosphorylation of annexin II by endogenous PKC and phosphorylation of myelin basic protein by PKCalpha. In both systems, the use of single Ca2+-binding-site mutants of annexin V led to a partial reversal of inhibition, and the Ca2+-binding site located in the first domain of annexin V was found to have the most important role. An increase in the number of mutated Ca2+-binding sites led to a greater loss of inhibition. These results corroborated those showing the progressive loss of binding of these mutants to phospholipid liposomes. In conclusion, we show that PKC inhibition by annexin V is the consequence of a mechanism involving phospholipid sequestration by annexin V, and that the Ca2+-binding site located in domain 1 of annexin V plays a predominant role in this process. In addition, we show that the R122AIK site, which may act analogously to a PKC-inhibitory pseudosubstrate site, is not involved in PKC inhibition, and that a peptide corresponding to the C-terminal tail of annexin V inhibits PKC activity but to a lesser extent than annexin V itself.

Adenosine Triphosphate↗

PubMed1998

Interactions of benzodiazepine derivatives with annexins.

Human annexins III and V, members of the annexin family of calcium- and membrane-binding proteins, were complexed within the crystals with BDA452, a new 1,4-benzodiazepine derivative by soaking and co-crystallization methods. The crystal structures of the complexes were analyzed by x-ray crystallography and refined to 2.3- and 3.0-A resolution. BDA452 binds to a cleft which is located close to the N-terminus opposite to the membrane binding side of the proteins. Biophysical studies of the interactions of various benzodiazepine derivatives with annexins were performed to analyze the binding of benzodiazepines to annexins and their effects on the annexin-induced calcium influx into phosphatidylserine/phosphatidylethanolamine liposomes. Different effects were observed with a variety of benzodiazepines and different annexins depending on both the ligand and the protein. Almost opposite effects on annexin function are elicited by BDA250 and diazepam, its 7-chloro-derivative. We conclude that benzodiazepines modulate the calcium influx activity of annexins allosterically by stabilizing or destabilizing the conducting state of peripherally bound annexins in agreement with suggestions by Kaneko (Kaneko, N., Ago, H., Matsuda, R., Inagaki, E., and Miyano, M. (1997) J. Mol. Biol., in press).

Amino Acid Sequence↗

PubMed1998

IL-6 stimulates annexin 1 expression and translocation and suggests a new biological role as class II acute phase protein.

Annexin 1 (Ax 1), a protein whose synthesis and secretion are induced during the inflammatory response, has been proposed as a mediator of the anti-inflammatory action of glucocorticoids. To gain insight into a broader role of Ax 1 during the inflammatory response, the authors have investigated how pro-inflammatory cytokines [interleukin 1 (IL-1), IL-6 and tumour necrosis factor alpha (TNF-alpha)] affect Ax 1 expression and regulation at transcriptional and translational levels. The authors show that induction of the Ax 1 protein and its translocation to the cell membrane are stimulated by interleukin 6. However neither IL-1 nor TNF-alpha display these effects. Analysis of 5'-deletion mutants and the full length Ax 1 promoter fused to a luciferase reporter gene using transient transfections of human lung adenocarcinoma A 549 cells identified a unique 30 bp region of the Ax 1 promoter as critical for the responsiveness of the reporter gene to IL-6 and dexamethasone. Gel retardation and supershift assays showed that IL-6 stimulation is mediated by a C/EBP beta-like transcriptional factor. These data suggest that Ax 1 may participate in host defence as a new acute class II phase protein.

Acute-Phase Proteins↗