Miro-1 links mitochondria and microtubule dynein motors to control lymphocyte migration and polarity

The recruitment of leukocytes to sites of inflammation is crucial for a functional immune response. In the present work, we explored the role of mitochondria in lymphocyte adhesion, polarity, and migration. We show that during adhesion to the activated endothelium under physiological flow conditions, lymphocyte mitochondria redistribute to the adhesion zone together with the microtubule-organizing center (MTOC) in an integrin-dependent manner. Mitochondrial redistribution and efficient lymphocyte adhesion to the endothelium require the function of Miro-1, an adaptor molecule that couples mitochondria to microtubules. Our data demonstrate that Miro-1 associates with the dynein complex. Moreover, mitochondria accumulate around the MTOC in response to the chemokine CXCL12/SDF-1α this redistribution is regulated by Miro-1. CXCL12-dependent cell polarization and migration are reduced in Miro-1-silenced cells, due to impaired myosin II activation at the cell uropod and diminished actin polymerization. These data point to a key role of Miro-1 in the control of lymphocyte adhesion and migration through the regulation of mitochondrial redistribution.This study was supported by SAF2011-25834 from the Spanish Ministry of Science and Innovation, INDISNET-S2011/BMD-2332 from the Comunidad de Madrid, Red Cardiovascular RD 12-0042-0056 from Instituto Salud Carlos III (ISCIII), and ERC-2011-AdG 294340- GENTRIS. J.M.G.-G. received salary support from the Miguel Servet (CP11/00145) ISCIII program. R.V.-B. was supported by a Juan de la Cierva postdoctoral contract from the Spanish Ministry of Economy and Competiveness (JCI-2011-09663

Clathrin regulates lymphocyte migration by driving actin accumulation at the cellular leading edge

Lymphocyte migration, which is essential for effective immune responses, belongs to the so-called amoeboid migration. The lymphocyte migration is up to 100 times faster than between mesenchymal and epithelial cell types. Migrating lymphocytes are highly polarized in three well-defined structural and functional zones: uropod, medial zone, and leading edge (LE). The actiomyosin-dependent driving force moves forward the uropod, whereas massive actin rearrangements protruding the cell membrane are observed at the LE. These actin rearrangements resemble those observed at the immunological synapse driven by clathrin, a protein normally involved in endocytic processes. Here, we used cell lines as well as primary lymphocytes to demonstrate that clathrin and clathrin adaptors colocalize with actin at the LE of migrating lymphocytes, but not in other cellular zones that accumulate both clathrin and actin. Moreover, clathrin and clathrin adaptors, including Hrs, the clathrin adaptor for multivesicular bodies, drive local actin accumulation at the LE. Clathrin recruitment at the LE resulted necessary for a complete cell polarization and further lymphocyte migration in both 2D and 3D migration models. Therefore, clathrin, including the clathrin population associated to internal vesicles, controls lymphocyte migration by regulating actin rearrangements occurring at the LE.This work was supported by the grants from the Spanish Ministry of Science and Technology (MICINN; BFU2011-29450 to E.V.) and Ministry of Economy and Competitiveness (MINECO; SAF2014-56716-REDT and BFU2014-59585-R to E.V., SAF2011-25834 to F.S.M., SAF2014-58895-JIN to A.C.A and BFU2014-54181-P to J.L.C.), the Madrid regional government (INDISNET-S2011/BMD-2332 to F.S.M.) and the European Research Council (ERC-2011-AdG 294340-GENTRIS to F.S.M.). We are grateful to the “Centro de Transfusión” of the “Comunidad Autónoma de Madrid” for providing the Buffy Coats

Different states of integrin LFA-1 aggregation are controlled through its association with tetraspanin CD9

This is the author’s version of a work that was accepted for publication in Biochimica et Biophysica Acta - Mollecular Cell Research. A definitive version was subsequently published in Biochimica et Biophysica Acta - Mollecular Cell Research, 1853.10 (2015): 2464-2480 DOI: 10.1016/j.bbamcr.2015.05.018The tetraspanin CD9 has been shown to interact with different members of the β1 and β3 subfamilies of integrins, regulating through these interactions cell adhesion, migration and signaling. Based on confocal microscopy co-localization and on coimmunoprecipitation results, we report here that CD9 associates with the β2 integrin LFA-1 in different types of leukocytes including T, B and monocytic cells. This association is resistant to stringent solubilisation conditions which, together with data from chemical crosslinking, in situ Proximity Ligation Assays and pull-down experiments, suggests a primary/direct type of interaction mediated by the Large Extracellular Loop of the tetraspanin. CD9 exerts inhibitory effects on the adhesive function of LFA-1 and on LFA-1-dependent leukocyte cytotoxic activity. The mechanism responsible for this negative regulation exerted by CD9 on LFA-1 adhesion does not involve changes in the affinity state of this integrin but seems to be related to alterations in its state of aggregationThis work was supported by grant SAF2012-34561 from the Spanish «Ministerio de Economía y Competitividad-MINECO», (to C.C.). R.R.M. salary is supported by a «Profesor Ayudante» position from Departamento de Biología, Facutad de Ciencias, Universidad Autónoma de Madri

Metodología experimental aplicada a la Inmunología Molecular

El objetivo general del proyecto es aplicar un modelo pedagógico en el que participen los alumnos de manera activa y apliquen el método científico en base a los conocimientos que han adquirido, resolviendo y realizando un caso práctico en el laboratorio. Integra una estrategia didáctica que va a fomentar la participación activa del alumnado provocando un aprendizaje significativo, ya que el alumno tiene que resolver mediante el razonamiento un caso práctico y luego integrarlo en el laboratorio con el uso de una técnica ampliamente utilizada en Inmunología, como es la citometría de flujo.Depto. de Arquitectura de Computadores y AutomáticaFac. de InformáticaFALSEInnovasubmitte

Re-writing the natural history of pain and related symptoms in the joint hypermobility syndrome/Ehlers-Danlos syndrome, hypermobility type

Joint hypermobility syndrome (JHS) and Ehlers-Danlos syndrome, hypermobility type (EDS-HT) are two clinically overlapping connective tissue disorders characterized by chronic/recurrent pain, joint instability complications, and minor skin changes. Fatigue and headache are also common, although are not yet considered diagnostic criteria. JHS/EDS-HT is a unexpectedly common condition that remains underdiagnosed by most clinicians and pain specialists. This results in interventions limited to symptomatic and non-satisfactory treatments, lacking reasonable pathophysiologic rationale. In this manuscript the fragmented knowledge on pain, fatigue, and headache in JHS/EDS is presented with review of the available published information and a description of the clinical course by symptoms, on the basis of authors' experience. Pathogenic mechanisms are suggested through comparisons with other functional somatic syndromes (e.g., chronic fatigue syndrome, fibromyalgia, and functional gastrointestinal disorders). The re-writing of the natural history of JHS/EDS-HT is aimed to raise awareness among clinical geneticists and specialists treating chronic pain conditions about pain and other complications of JHS/EDS-HT. Symptoms' clustering by disease stage is proposed to investigate both the molecular causes and the symptoms management of JHS/EDS-HT in future studies. © 2013 Wiley Periodicals, Inc.Joint hypermobility syndrome (JHS) and Ehlers–Danlos syndrome, hypermobility type (EDS-HT) are two clinically overlapping connective tissue disorders characterized by chronic/ recurrent pain, joint instability complications, and minor skin changes. Fatigue and headache are also common, although are not yet considered diagnostic criteria. JHS/EDS-HT is a unexpectedly common condition that remains underdiagnosed by most clinicians and pain specialists. This results in interventions limited to symptomatic and non-satisfactory treatments, lacking reasonable pathophysiologic rationale. In this manuscript the fragmented knowledge on pain, fatigue, and headache in JHS/ EDS is presented with review of the available published information and a description of the clinical course by symptoms, on the basis of authors’ experience. Pathogenic mechanisms are suggested through comparisons with other functional somatic syndromes (e.g., chronic fatigue syndrome, fibromyalgia, and functional gastrointestinal disorders). The re-writing of the natural history of JHS/EDS-HT is aimed to raise awareness among clinical geneticists and specialists treating chronic pain conditions about pain and other complications of JHS/EDS-HT. Symptoms’ clustering by disease stage is proposed to investigate both the molecular causes and the symptoms management of JHS/EDS-HT in future studie

A novel bistable device to study mechanosensitive cell responses to instantaneous stretch

The behavior of cells and tissues in vivo is determined by the integration of multiple biochemical and mechanical signals. Of the mechanical signals, stretch has been studied for decades and shown to contribute to pathophysiological processes. Several different stretch devices have been developed for in vitro investigations of cell stretch. In this work, we describe a new 3D-printed uniaxial stretching device for studying cell response to rapid deformation. The device is a bistable compliant mechanism holding two equilibrium states—an unstretched and stretched configuration—without the need of an external actuator. Furthermore, it allows multiple simultaneous measurements of different levels of stretch on a single substrate and is compatible with standard immunofluorescence imaging of fixed cells as well as live-cell imaging. To demonstrate the effectiveness of the device to stretch cells, a test case using aligned myotubes is presented. Leveraging material area changes associated with deformation of the substrate, changes in nuclei density provided evidence of affine deformation between cells and substrate. Furthermore, intranuclear deformations were also assessed and shown to deform non-affinely. As a proof-of-principle of the use of the device for mechanobiological studies, we uniaxially stretched aligned healthy and dystrophic myotubes that displayed different passive mechanical responses, consistent with previous literature in the field. We also identified a new feature in the mechanoresponse of dystrophic myotubes, which is of potential interest for identifying the diseased cells based on a quick mechanical readout. While some applications of the device for elucidating passive mechanical responses are demonstrated, the simplicity of the device allows it to be potentially used for other modes of deformation with little modifications.ISSN:2772-950

A preclinical model of peripheral T‐cell lymphoma GATA3 reveals DNA damage response pathway vulnerability

Abstract Peripheral T‐cell lymphoma (PTCL) represents a rare group of heterogeneous diseases in urgent need of effective treatments. A scarcity of disease‐relevant preclinical models hinders research advances. Here, we isolated a novel mouse (m)PTCL by serially transplanting a lymphoma from a germinal center B‐cell hyperplasia model (Cγ1‐Cre Blimp1fl/fl) through immune‐competent mice. Lymphoma cells were identified as clonal TCRβ+ T‐helper cells expressing T‐follicular helper markers. We also observed coincident B‐cell activation and development of a de novo B‐cell lymphoma in the model, reminiscent of B‐cell activation/lymphomagenesis found in human PTCL. Molecular profiling linked the mPTCL to the high‐risk “GATA3” subtype of PTCL, showing GATA3 and Th2 gene expression, PI3K/mTOR pathway enrichment, hyperactivated MYC, and genome instability. Exome sequencing identified a human‐relevant oncogenic β‐catenin mutation possibly involved in T‐cell lymphomagenesis. Prolonged treatment responses were achieved in vivo by targeting ATR in the DNA damage response (DDR), a result corroborated in PTCL cell lines. This work provides mechanistic insight into the molecular and immunological drivers of T‐cell lymphomagenesis and proposes DDR inhibition as an effective and readily translatable therapy in PTCL

F-actin-binding protein drebrin regulates CXCR4 recruitment to the immune synapse

Acknowledgements This work was partly supported by EU-México FONCICYT –C002-2008-1 ALA/127249, SAF-2008-02635, INSINET 01592006 CAM, Red RECAVA RD06/0014-0030 and FIPSE 36658/07 grants. E.V.C. holds a Ramón y Cajal contract from the Spanish Ministry of Science and Innovation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We thank H. de la Fuente for statistical assistance. Editorial assistance was provided by S. Bartlett. G.M. is supported by the European Union-funded International Graduate Program in Molecular Medicine.The adaptive immune response depends on the interaction of T cells and antigen-presenting cells at the immune synapse. Formation of the immune synapse and the subsequent T-cell activation are highly dependent on the actin cytoskeleton. In this work, we describe that T cells express drebrin, a neuronal actin-binding protein. Drebrin colocalizes with the chemokine receptor CXCR4 and F-actin at the peripheral supramolecular activation cluster in the immune synapse. Drebrin interacts with the cytoplasmic tail of CXCR4 and both proteins redistribute to the immune synapse with similar kinetics. Drebrin knockdown in T cells impairs the redistribution of CXCR4 and inhibits actin polymerization at the immune synapse as well as IL-2 production. Our data indicate that drebrin exerts an unexpected and relevant functional role in T cells during the generation of the immune response.Depto. de Biología CelularFac. de Ciencias BiológicasTRUEpu

Loss-of-function variants in exon 4 of TAB2 cause a recognizable multisystem disorder with cardiovascular, facial, cutaneous, and musculoskeletal involvement

This study aimed to describe a multisystemic disorder featuring cardiovascular, facial, musculoskeletal, and cutaneous anomalies caused by heterozygous loss-of-function variants in TAB2