Anne Pierres

Aix-Marseille Université, Marsiglia, Provence-Alpes-Côte d'Azur, France

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Publications (68)252.01 Total impact

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    ABSTRACT: Contact with Leishmania leads to a decreases in mononuclear phagocyte adherence to connective tissue. In this work, we studied the early stages of bond formation between VLA4 and fibronectin, measured the kinetics of membrane alignment and the monocyte cytoplasm spreading area over a fibronectin-coated surface, and studied the expression of high affinity integrin epitope in uninfected and Leishmania-infected human monocytes. Our results show that the initial VLA4-mediated interaction of Leishmania-infected monocyte with a fibronectin-coated surface is preserved, however, the later stage, leukocyte spreading over the substrate is abrogated in Leishmania-infected cells. The median of spreading area was 72 [55-89] μm(2) for uninfected and 41 [34-51] μm(2) for Leishmania-infected monocyte. This cytoplasm spread was inhibited using an anti-VLA4 blocking antibody. After the initial contact with the fibronectrin-coated surface, uninfected monocyte quickly spread the cytoplasm at a 15 μm(2) s(-1) ratio whilst Leishmania-infected monocytes only made small contacts at a 5.5 μm(2) s(-1) ratio. The expression of high affinity epitope by VLA4 (from 39 ± 21% to 14 ± 3%); and LFA1 (from 37 ± 32% to 18 ± 16%) molecules was reduced in Leishmania-infected monocytes. These changes in phagocyte function may be important for parasite dissemination and distribution of lesions in leishmaniasis.
    Full-text · Article · Sep 2015 · Scientific Reports
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    ABSTRACT: T lymphocytes need to detect rare cognate foreign peptides amongst numerous foreign and self-peptides. This discrimination seems to be based on the kinetics of TCRs binding to their peptide-MHC (pMHC) ligands, but there is little direct information on the minimum time required for processing elementary signaling events and deciding to initiate activation. Here, we used interference reflection microscopy to study the early interaction between transfected human Jurkat T cells expressing the 1G4 TCR and surfaces coated with five different pMHC ligands of 1G4. The pMHC concentration required for inducing 50% maximal IFN-γ production by T cells, and 1G4-pMHC dissociation rates measured in soluble phase or on surface-bound molecules, displayed 6-7 fold variation among pMHCs. When T cells were dropped onto pMHC-coated surfaces, rapid spreading occurred after a 2-minute lag. The initial spreading rate measured during the first 45 s, and the contact area, were strongly dependent on the encountered TCR ligand. However, the lag duration did not significantly depend on encountered ligand. In addition, spreading appeared to be an all-or-none process, and the fraction of spreading cells was tightly correlated to the spreading rate and spreading area. Thus, T cells can discriminate between fairly similar TCR ligands within 2 minutes. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Full-text · Article · Mar 2015 · European Journal of Immunology

  • No preview · Article · Jul 2014 · The Journal of Cell Biology
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    ABSTRACT: The nature of an inherited platelet disorder was investigated in three siblings affected by severe bleeding. Using whole-exome sequencing, we identified the culprit mutation (cG742T) in the RAS guanyl-releasing protein-2 (RASGRP2) gene coding for calcium- and DAG-regulated guanine exchange factor-1 (CalDAG-GEFI). Platelets from individuals carrying the mutation present a reduced ability to activate Rap1 and to perform proper αIIbβ3 integrin inside-out signaling. Expression of CalDAG-GEFI mutant in HEK293T cells abolished Rap1 activation upon stimulation. Nevertheless, the PKC- and ADP-dependent pathways allow residual platelet activation in the absence of functional CalDAG-GEFI. The mutation impairs the platelet's ability to form thrombi under flow and spread normally as a consequence of reduced Rac1 GTP-binding. Functional deficiencies were confined to platelets and megakaryocytes with no leukocyte alteration. This contrasts with the phenotype seen in type III leukocyte adhesion deficiency caused by the absence of kindlin-3. Heterozygous did not suffer from bleeding and have normal platelet aggregation; however, their platelets mimicked homozygous ones by failing to undergo normal adhesion under flow and spreading. Rescue experiments on cultured patient megakaryocytes corrected the functional deficiency after transfection with wild-type RASGRP2. Remarkably, the presence of a single normal allele is sufficient to prevent bleeding, making CalDAG-GEFI a novel and potentially safe therapeutic target to prevent thrombosis.
    Full-text · Article · Jun 2014 · Journal of Experimental Medicine
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    ABSTRACT: A key step of adaptive immune responses is the T lymphocyte capacity to detect the presence of foreign antigens on specialized cells with high speed and specificity during contacts lasting a few minutes. Much evidence suggests that there is a deep link between the lifetime of molecular interactions between T cell receptors and ligands and T cell activation, but the precise mechanisms of bond formation and dissociation remain incompletely understood. Previous experiments done with interference reflection microscopy/reflection interference contrast microscopy disclosed transverse motions with several nanometer average amplitude of micrometer size membrane zones. More recently, total internal reflection fluorescence microscopy was used to show that the initial interaction between primary T lymphocytes and model surfaces involved the tip of microvilli (typically 0.2 µm2 area) generating apparent contacts of a few seconds that allowed cells to detect ligands of their membrane receptors. Here we show that these microvilli displayed minimal lateral displacements but quantitative fluorescence measurement suggested the occurrence of spontaneous transverse fluctuations of order of 67 nm amplitude during 1-s observation periods. This may play a major role in membrane receptor engagement and ensuing signal generation.
    Preview · Article · Mar 2014 · Cellular and Molecular Bioengineering
  • Anne Pierres · Pierre Bongrand

    No preview · Book · Jan 2014
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    ABSTRACT: Adaptive immune responses are triggered by the rapid and sensitive detection of MHC-bound peptides by TCRs. The kinetics of early TCR/APC contacts are incompletely known. In this study, we used total internal reflection fluorescence microscopy to image human T cell membranes near model surfaces: contact was mediated by mobile protrusions of <0.4 μm diameter. The mean lifetime of contacts with a neutral surface was 8.6 s. Adhesive interactions increased mean contact time to 27.6 s. Additional presence of TCR ligands dramatically decreased contact to 13.7 s, thus evidencing TCR-mediated triggering of a pulling motion within seconds after ligand encounter. After an interaction typically involving 30-40 contacts formed during a 1-min observation period, TCR stimulation triggered a rapid and active cell spreading. Pulling events and cell spreading were mimicked by pharmacological phospholipase Cγ1 activation, and they were prevented by phospholipase Cγ1 inhibition. These results provide a quantitative basis for elucidating the earliest cell response to the detection of foreign Ags.
    No preview · Article · Jul 2013 · The Journal of Immunology
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    ABSTRACT: Blood leukocytes have a remarkable capacity to bind to and stop on specific blood vessel areas. Many studies have disclosed a key role of integrin structural changes following the interaction of rolling leukocytes with surface-bound chemoattractants. However, the functional significance of structural data and mechanisms of cell arrest are incompletely understood. Recent experiments revealed the unexpected complexity of several key steps of cell-surface interaction: (i) ligand-receptor binding requires a minimum amount of time to proceed and this is influenced by forces. (ii) Also, molecular interactions at interfaces are not fully accounted for by the interaction properties of soluble molecules. (iii) Cell arrest depends on nanoscale topography and mechanical properties of the cell membrane, and these properties are highly dynamic. Here, we summarize these results and we discuss their relevance to recent functional studies of integrin-receptor association in cells from a patient with type III leukocyte adhesion deficiency. It is concluded that an accurate understanding of all physical events listed in this review is needed to unravel the precise role of the multiple molecules and biochemical pathway involved in arrest triggering.
    Preview · Article · May 2013 · Frontiers in Immunology

  • No preview · Article · Oct 2012 · Journal of Geriatric Oncology
  • A Pierres · AM Benoliel · P Bongrand

    No preview · Article · Aug 2012
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    ABSTRACT: p8 is a stress gene whose activity is necessary for tumor development and progression. The acquisition of invasive properties by transformed cells is a key event in tumor development. In order to establish whether p8 is involved or not in this phenomenon, we assessed the capacity of p8 at influencing cell adhesion, migration, invasion, and tumorigenesis of pancreatic cancer cells. p8 expression was knocked down by a small interfering RNA (siRNA) in pancreatic cancer-derived Panc-1 and MiaPaCa-2 cells and subsequent changes in cell adhesion, migration, invasion, and tumorigenesis were assessed. Influence of p8 silencing on gene expression was analyzed using cDNA microarrays. The influence of inhibiting CDC42, one of the genes most over-expressed in p8-silenced cells, on the changes observed in p8-silenced cells was also evaluated. Finally, the tumorigenic capacities of Panc-1 cells transfected with control siRNA or p8 siRNA were compared by assessing their ability to form colonies in soft agar and to grow as xenografts in nude mice. Knocking-down p8 in pancreatic cancer cells in vitro decreased migration and invasion while increasing cell adhesion; over-expression produced the opposite effect. Knocking down CDC42 reversed almost completely the effects of silencing p8 in vitro. Finally, cells transfected with p8 siRNA were almost unable to form colonies in soft agar. In addition, p8-deficient Panc-1 cells did not develop tumors when injected subcutaneously in nude mice. In conclusion, p8 expression controls pancreatic cancer cell migration, invasion and adhesion, three processes required for metastasis, at least in part, through CDC42, a major regulator of cytoskeleton organization. J. Cell. Physiol. 226: 3442–3451, 2011. © 2011 Wiley Periodicals, Inc.
    No preview · Article · Dec 2011 · Journal of Cellular Physiology
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    ABSTRACT: IntroductionImmunosenescence embraces the whole of age-induced changes observed in the immunomodulatory functions of a living organism, and is mostly characterized by a decrease in cell-mediated immunity and important modifications of the immunological repertoire. The impact of the pathology on ageing immunity is poorly understood and few data are available on the immunological status of old polypathological patients.
    No preview · Article · May 2011 · La Revue de Médecine Interne
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    ABSTRACT: Leukocyte adhesion deficiency type III is a recently described condition involving a Glanzmann-type bleeding syndrome and leukocyte adhesion deficiency. This was ascribed to a defect of the FERMT3 gene resulting in abnormal expression of kindlin-3, a protein expressed in hematopoietic cells with a major role in the regulation of integrin activation. In this article, we describe a patient with a new mutation of FERMT3 and lack of kindlin-3 expression in platelets and leukocytes. We assayed quantitatively the first steps of kindlin-3-defective leukocyte adhesion, namely, initial bond formation, bond strengthening, and early spreading. Initial bond formation was readily stimulated with neutrophils stimulated by fMLF, and neutrophils and lymphocytes stimulated by a phorbol ester or Mn(2+). In contrast, attachment strengthening was defective in the patient's lymphocytes treated with PMA or Mn(2+), or fMLF-stimulated neutrophils. However, attachment strengthening was normal in patient's neutrophils treated with phorbol ester or Mn(2+). In addition, the patient's T lymphocytes displayed defective integrin-mediated spreading and a moderate but significant decrease of spreading on anti-CD3-coated surfaces. Patient's neutrophils displayed a drastic alteration of integrin-mediated spreading after fMLF or PMA stimulation, whereas signaling-independent Mn(2+) allowed significant spreading. In conclusion, the consequences of kindlin-3 deficiency on β(2) integrin function depend on both cell type and the stimulus used for integrin activation. Our results suggest looking for a possible kindlin-3 involvement in membrane dynamical event independent of integrin-mediated adhesion.
    Full-text · Article · Mar 2011 · The Journal of Immunology
  • Siham Sabri · Anne Pierres · A M Benoliel · Pierre Bongrand
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    ABSTRACT: We tested the hypothesis that nonspecific repulsion, as a result of electrostatic forces and (or) steric stabilization effects, impaired adhesion more efficiently under dynamic than under static conditions. Cells from the human monocytic line THP1 were plated on a glass surface. Spherical particles bearing monoclonal antibodies specific for antigens expressed by THP1 cells (CD11b, CD18, CD35, CD64) were then added and adhesion was quantified. The effect of neuraminidase treatment of THP1 cells was also studied. Adhesion was then measured in a flow chamber under low shear flow (wall shear rate was 11 or 22 s-1), allowing a quantitative determination of cell adhesion frequency. The following conclusions were obtained: (i) under static conditions, neuraminidase treatment had little effect on adhesion (only CD18-mediated interaction was significantly increased at 4 degrees C after enzyme treatment); (ii) under dynamic conditions, neuraminidase treatment significantly increased binding; (iii) surprisingly, there was no clear relationship between the length of adhesion molecules involved in the interaction and binding efficiency; and (iv) such parameters as cell shape and topographical distribution of adhesion molecules may strongly influence adhesion under flow. It is concluded that a dynamic reorganization of the pericellular matrix following intercellular contact may play an important role in regulating adhesion.
    No preview · Article · Jan 2011 · Biochemistry and Cell Biology
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    ABSTRACT: Immunosenescence embraces the whole of age-induced changes observed in the immunomodulatory functions of a living organism, and is mostly characterized by a decrease in cell-mediated immunity and important modifications of the immunological repertoire. The impact of the pathology on ageing immunity is poorly understood and few data are available on the immunological status of old polypathological patients. We report the results of a prospective study aiming at characterizing several established immunological parameters in patients of 75 years old or more, and admitted for diverse pathologies in a unit of acute geriatric ward. Among the 51 included patients (35 women and 16 men), 90% displayed poly-pathologies. We found a prevalence of 86% of immunological abnormalities, with lymphopenia among 41% of the patients (<1500/mm(3)) and abnormal lymphocytes phenotypes among 95% of the oldest patients (>85 years). A strong skewing towards memory T lymphocytes (CD45RO+) over naive T lymphocytes (CD45RA+) was found in 80% of the cases and inverted CD4/CD8 T cells ratio was observed in 12% of our patients. Vitamin D insufficiency (<30ng/ml), which is frequent among the patients (94%), is a predictive factor for T and B cell lymphopenia. Immunological abnormalities are frequent in this frail population and lymphopenia, in particular, could constitute a reinforcing factor of fragility. Vitamin D deficiency could also affect elderly patients' immunity.
    No preview · Article · Nov 2010 · La Revue de Médecine Interne
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    ABSTRACT: A critical step of the adaptive response is the detection of foreign peptides on antigen presenting cells by T lymphocytes. It is a major challenge for a T lymphocyte to detect the presence of a few tens of cognate ligands or less on the membrane of a cell exposing millions of protein molecules. Detection is followed by the cell decision to undergo full or partial activation or even to start an inhibitory program. While the measurement of cell proliferation or cytokine synthesis is accepted as a reliable means of monitoring T lymphocyte activation, this requires hours or days to complete, which is a significant drawback to relate decision to particular signaling events or to assess lymphocyte reactivity in patients. Here we show that the contact area formed between T lymphocytes and potentially activating surfaces is exquisitely correlated to the proliferative response measured with the standard CFSE technique. Correlation is even better than the Erk activation that was reported as a digital reporter of cell activation. The simple and accurate method of assessing lymphocyte-to-surface contact extension that we describe might be very useful both to monitor lymphocyte reactivity for clinical purposes and to identify early steps of lymphocyte activation.
    Full-text · Article · Oct 2010 · Journal of immunological methods
  • E Crétel · I Veen · A Pierres · P Bongrand · G Gavazzi
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    ABSTRACT: The susceptibility of elderly people to infectious diseases is usually associated to increasing risk factors found in young adults. However, the role of immune function ageing is associated with the decline of immune function but this decline is not homogenous. Some functions such as the cellular immune system are altered but others are enhanced such as innate immunity. The important events of immune ageing are modifications of lymphocyte subsets with accumulation of memory cells, decrease in proliferative response, and a chronic inflammatory state. The chronic antigenic load throughout life is responsible for gaps in the antigenic system with a greater sensitivity to new antigens. These immune system changes are all the more important that diseases are severe and that denutrition is associated. These diseases will speed up the ageing process. The interaction between immunosenescence and pathology is an important phenomenon to consider. This review outlines the immune system changes due to ageing, their relationship with diseases of the aged patient, and the consequences of these modifications on vaccination effectiveness.
    No preview · Article · Jun 2010 · Médecine et Maladies Infectieuses
  • E. Crétel · I. Veen · A. Pierres · P. Bongrand · G. Gavazzi
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    ABSTRACT: The susceptibility of elderly people to infectious diseases is usually associated to increasing risk factors found in young adults. However, the role of immune function ageing is associated with the decline of immune function but this decline is not homogenous. Some functions such as the cellular immune system are altered but others are enhanced such as innate immunity. The important events of immune ageing are modifications of lymphocyte subsets with accumulation of memory cells, decrease in proliferative response, and a chronic inflammatory state. The chronic antigenic load throughout life is responsible for gaps in the antigenic system with a greater sensitivity to new antigens. These immune system changes are all the more important that diseases are severe and that denutrition is associated. These diseases will speed up the ageing process. The interaction between immunosenescence and pathology is an important phenomenon to consider. This review outlines the immune system changes due to ageing, their relationship with diseases of the aged patient, and the consequences of these modifications on vaccination effectiveness.
    No preview · Article · Jun 2010 · Médecine et Maladies Infectieuses
  • E Cretel · D Touchard · A M Benoliel · P Bongrand · A Pierres
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    ABSTRACT: Cells continually probe their environment to adapt their behaviour. A current challenge is to determine how they analyse nearby surfaces and how they process information to take decisions. We addressed this problem by monitoring human T lymphocyte attachment to surfaces coated with activating anti-CD3 or control anti-HLA antibodies. Interference reflection microscopy allowed us to monitor cell-to-surface apposition with a few nanometre vertical resolution during the first minutes following contact. We found that (i) when a cell fell on a surface, contact extension was preceded by a lag of several tens of seconds. (ii) During this lag, vertical membrane undulations seemed to generate transient contacts with underlying surfaces. (iii) After the lag period, the contact area started increasing linearly with a rate of about 1.5 µm(2) s(-1) on activating surfaces and about 0.2 µm(2) s(-1) on control surfaces. (iv) Concomitantly with lateral surface extension, the apparent distance between cell membranes and surfaces steadily decreased. These results are consistent with the hypothesis that the cell decision to spread rapidly on activating surfaces resulted from the integration of information yielded by transient contacts with these surfaces generated by membrane undulations during a period of about 1 min.
    No preview · Article · May 2010 · Journal of Physics Condensed Matter
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    ABSTRACT: Phagocyte interaction with biomaterials plays an important role in inflammatory reactions. Numerous reports have shown that phagocyte behaviour at interfaces is strongly influenced by the nature and conformation of adsorbed biomolecules, which reflects, in an indirect way, the physico-chemical properties of underlying surfaces. Cell–surface interactions were thus thought to be governed by recognition events between membrane receptors and specific sites exposed by biomolecules. More recently, a growing number of reports have demonstrated that cells are also strongly influenced by physical or geometrical features such as surface rigidity or roughness and ligand topography. Here we review recent evidence supporting this concept and we describe recently disclosed cell dynamic properties that might be relevant to this phenomenon. Cell membrane movements at interfaces are expected to generate forces and deformations, and these phenomena are, in turn, expected to trigger or modulate signaling cascades through a number of processes including force-induced conformational change of membrane receptors, and alterations of in-plane movements of membrane molecules. It is suggested that a prerequisite to understanding cell behaviour at interfaces is to record all early molecular events triggered by membrane-to-surface approach and define cell decisions.
    No preview · Article · Apr 2010 · Journal of Adhesion Science and Technology

Publication Stats

2k Citations
252.01 Total Impact Points

Institutions

  • 2007-2015
    • Aix-Marseille Université
      • Centre Interdisciplinaire de Nanoscience de Marseille
      Marsiglia, Provence-Alpes-Côte d'Azur, France
  • 2004-2013
    • French National Centre for Scientific Research
      • Center for Interdisciplinary Nanoscience
      Lutetia Parisorum, Île-de-France, France
  • 1998-2013
    • French Institute of Health and Medical Research
      Lutetia Parisorum, Île-de-France, France
  • 1994-2011
    • Unité Inserm U1077
      Caen, Lower Normandy, France