Publications by authors named "Helena Batoulis"

9 Publications

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The RESOLUTE consortium: unlocking SLC transporters for drug discovery.

Authors:
Giulio Superti-Furga Daniel Lackner Tabea Wiedmer Alvaro Ingles-Prieto Barbara Barbosa Enrico Girardi Ulrich Goldmann Bettina Gürtl Kristaps Klavins Christoph Klimek Sabrina Lindinger Eva Liñeiro-Retes André C Müller Svenja Onstein Gregor Redinger Daniela Reil Vitaly Sedlyarov Gernot Wolf Matthew Crawford Robert Everley David Hepworth Shenping Liu Stephen Noell Mary Piotrowski Robert Stanton Hui Zhang Salvatore Corallino Andrea Faedo Maria Insidioso Giovanna Maresca Loredana Redaelli Francesca Sassone Lia Scarabottolo Michela Stucchi Paola Tarroni Sara Tremolada Helena Batoulis Andreas Becker Eckhard Bender Yung-Ning Chang Alexander Ehrmann Anke Müller-Fahrnow Vera Pütter Diana Zindel Bradford Hamilton Martin Lenter Diana Santacruz Coralie Viollet Charles Whitehurst Kai Johnsson Philipp Leippe Birgit Baumgarten Lena Chang Yvonne Ibig Martin Pfeifer Jürgen Reinhardt Julian Schönbett Paul Selzer Klaus Seuwen Charles Bettembourg Bruno Biton Jörg Czech Hélène de Foucauld Michel Didier Thomas Licher Vincent Mikol Antje Pommereau Frédéric Puech Veeranagouda Yaligara Aled Edwards Brandon J Bongers Laura H Heitman Ad P IJzerman Huub J Sijben Gerard J P van Westen Justine Grixti Douglas B Kell Farah Mughal Neil Swainston Marina Wright-Muelas Tina Bohstedt Nicola Burgess-Brown Liz Carpenter Katharina Dürr Jesper Hansen Andreea Scacioc Giulia Banci Claire Colas Daniela Digles Gerhard Ecker Barbara Füzi Viktoria Gamsjäger Melanie Grandits Riccardo Martini Florentina Troger Patrick Altermatt Cédric Doucerain Franz Dürrenberger Vania Manolova Anna-Lena Steck Hanna Sundström Maria Wilhelm Claire M Steppan

Nat Rev Drug Discov 2020 07;19(7):429-430

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http://dx.doi.org/10.1038/d41573-020-00056-6DOI Listing
July 2020

The packing density of a supramolecular membrane protein cluster is controlled by cytoplasmic interactions.

Elife 2017 07 19;6. Epub 2017 Jul 19.

Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany.

Molecule clustering is an important mechanism underlying cellular self-organization. In the cell membrane, a variety of fundamentally different mechanisms drive membrane protein clustering into nanometre-sized assemblies. To date, it is unknown whether this clustering process can be dissected into steps differentially regulated by independent mechanisms. Using clustered syntaxin molecules as an example, we study the influence of a cytoplasmic protein domain on the clustering behaviour. Analysing protein mobility, cluster size and accessibility to myc-epitopes we show that forces acting on the transmembrane segment produce loose clusters, while cytoplasmic protein interactions mediate a tightly packed state. We conclude that the data identify a hierarchy in membrane protein clustering likely being a paradigm for many cellular self-organization processes.
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http://dx.doi.org/10.7554/eLife.20705DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5536946PMC
July 2017

Electrostatic anchoring precedes stable membrane attachment of SNAP25/SNAP23 to the plasma membrane.

Elife 2017 02 27;6. Epub 2017 Feb 27.

Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany.

The SNAREs SNAP25 and SNAP23 are proteins that are initially cytosolic after translation, but then become stably attached to the cell membrane through palmitoylation of cysteine residues. For palmitoylation to occur, membrane association is a prerequisite, but it is unclear which motif may increase the affinities of the proteins for the target membrane. In experiments with rat neuroendocrine cells, we find that a few basic amino acids in the cysteine-rich region of SNAP25 and SNAP23 are essential for plasma membrane targeting. Reconstitution of membrane-protein binding in a liposome assay shows that the mechanism involves protein electrostatics between basic amino acid residues and acidic lipids such as phosphoinositides that play a primary role in these interactions. Hence, we identify an electrostatic anchoring mechanism underlying initial plasma membrane contact by SNARE proteins, which subsequently become palmitoylated at the plasma membrane.
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http://dx.doi.org/10.7554/eLife.19394DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5362264PMC
February 2017

Concentration Dependent Ion-Protein Interaction Patterns Underlying Protein Oligomerization Behaviours.

Sci Rep 2016 Apr 7;6:24131. Epub 2016 Apr 7.

Membrane Biochemistry, Life &Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany.

Salts and proteins comprise two of the basic molecular components of biological materials. Kosmotropic/chaotropic co-solvation and matching ion water affinities explain basic ionic effects on protein aggregation observed in simple solutions. However, it is unclear how these theories apply to proteins in complex biological environments and what the underlying ionic binding patterns are. Using the positive ion Ca(2+) and the negatively charged membrane protein SNAP25, we studied ion effects on protein oligomerization in solution, in native membranes and in molecular dynamics (MD) simulations. We find that concentration-dependent ion-induced protein oligomerization is a fundamental chemico-physical principle applying not only to soluble but also to membrane-anchored proteins in their native environment. Oligomerization is driven by the interaction of Ca(2+) ions with the carboxylate groups of aspartate and glutamate. From low up to middle concentrations, salt bridges between Ca(2+) ions and two or more protein residues lead to increasingly larger oligomers, while at high concentrations oligomers disperse due to overcharging effects. The insights provide a conceptual framework at the interface of physics, chemistry and biology to explain binding of ions to charged protein surfaces on an atomistic scale, as occurring during protein solubilisation, aggregation and oligomerization both in simple solutions and membrane systems.
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http://dx.doi.org/10.1038/srep24131DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4823792PMC
April 2016

Central nervous system infiltrates are characterized by features of ongoing B cell-related immune activity in MP4-induced experimental autoimmune encephalomyelitis.

Clin Immunol 2015 May 18;158(1):47-58. Epub 2015 Mar 18.

Department of Anatomy and Cell Biology, University of Wuerzburg, Koellikerstr. 6, 97070 Wuerzburg, Germany. Electronic address:

In multiple sclerosis (MS) lymphoid follicle-like aggregates have been reported in the meninges of patients. Here we investigated the functional relevance of B cell infiltration into the central nervous system (CNS) in MP4-induced experimental autoimmune encephalomyelitis (EAE), a B cell-dependent mouse model of MS. In chronic EAE, B cell aggregates were characterized by the presence of CXCL13(+) and germinal center CD10(+) B cells. Germline transcripts were expressed in the CNS and particularly related to TH17-associated isotypes. We also observed B cells with restricted VH gene usage that differed from clones found in the spleen. Finally, we detected CNS-restricted spreading of the antigen-specific B cell response towards a myelin and a neuronal autoantigen. These data imply the development of autonomous B cell-mediated autoimmunity in the CNS in EAE - a concept that might also apply to MS itself.
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http://dx.doi.org/10.1016/j.clim.2015.03.009DOI Listing
May 2015

The magnitude of the antigen-specific T cell response is separated from the severity of spinal cord histopathology in remitting-relapsing experimental autoimmune encephalomyelitis.

Glia 2012 May 8;60(5):794-805. Epub 2012 Feb 8.

Department of Anatomy I, University Hospitals of Cologne, Joseph-Stelzmann-Str. 9, 50931 Cologne, Germany.

Multiple sclerosis (MS) is an autoimmune disorder of the central nervous system. The remitting-relapsing experimental autoimmune encephalomyelitis (EAE) in the SJL mouse strain is a common animal model for MS and similar to the human disease it is considered to be T helper cell mediated. Besides interferon-γ secreting T(H)1 cells in particular the T(H)17 subset is believed to be highly pathogenic. Spreading of the T(H)1 and T(H)17 response to newly emerging determinants has been used to explain clinical disease relapse, but if the magnitude of the T(H)1/T(H)17 response is linked to clinical relapse severity has remained unresolved. Here, we assessed clinical EAE severity, the extent of spinal cord histopathology and the magnitude of the antigen-specific T helper cell and autoantibody response in proteolipid protein peptide 139-151 (PLP:139-151)-immunized SJL mice in clinical remission and relapse. We demonstrate that spinal cord histopathology comprised inflammation, demyelination as well as axonal loss and correlated well with clinical disease severity. Although the degree of spinal cord histopathology and clinical severity was separated from the PLP:139-151-specific T(H)1/T(H)17 cell and antibody response, it was linked to the number of infiltrating macrophages and activated microglia. In particular, there was a correlation between their secretion product interleukin-1β and the degree of axonal loss. Although CD4(+) T cells seem to be mainly involved in disease initiation, we suggest that it is the downstream activation of the innate immune response that defines the magnitude of the disease outcome.
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http://dx.doi.org/10.1002/glia.22309DOI Listing
May 2012

Resting of Cryopreserved PBMC Does Not Generally Benefit the Performance of Antigen-Specific T Cell ELISPOT Assays.

Cells 2012 Jul 30;1(3):409-27. Epub 2012 Jul 30.

Cellular Technology Ltd. (C.T.L), Shaker Heights, OH 44122, USA.

T cell monitoring is increasingly performed using cryopreserved PBMC. It has been suggested that resting of PBMC after thawing, that is, culturing them overnight in test medium, produces higher antigen-induced spot counts in ELISPOT assays. To evaluate the importance of overnight resting, we systematically tested cryopreserved PBMC from 25 healthy donors. CEF peptides (comprising CMV, EBV and flu antigens) were used to stimulate CD8 cells and mumps antigen to stimulate CD4 cells. The data show that resting significantly increased antigen-elicited T cell responses only for CEF high responder PBMC. The maximal gain observed was doubling of spot counts. For CEF low responders, and for mumps responders of either low- or high reactivity levels, resting had no statistically significant effect on the observed spot counts. Therefore, resting is not a generally applicable approach to improve ELISPOT assay performance, but can be recommended only for clinical subject cohorts and antigens for which it has a proven benefit. Because resting invariably leads to losing about half of the PBMC available for testing, and because doubling the PBMC numbers plated into the assay reliably doubles the antigen-induced spot counts, we suggest the latter approach as a simple and reliable alternative to resting for enhancing the performance of ELISPOT assays. Our data imply that resting is not required if PBMC were cryopreserved and thawed under conditions that minimize apoptosis of the cells. Therefore, this study should draw attention to the need to optimize freezing and thawing conditions for successful T cell work.
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http://dx.doi.org/10.3390/cells1030409DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3901103PMC
July 2012

Experimental autoimmune encephalomyelitis--achievements and prospective advances.

APMIS 2011 Dec 18;119(12):819-30. Epub 2011 Oct 18.

Department of Anatomy I, University of Cologne, Cologne, Germany.

Multiple sclerosis (MS) is an autoimmune disorder of the CNS. Different subtypes of the disease have been noted, and characterized by distinct clinical courses and histopathologic manifestations. The most intensively studied animal model of MS, experimental autoimmune encephalomyelitis (EAE), classically leads to deficits in motor functions, and is mediated by T helper cells. Recently, T(H)17 cells were ascribed an even greater pathogenic impact than T(H)1 cells, but new findings render this view controversial. Although classic EAE has been an invaluable tool, it does not cover the entire pathogenic entity of MS. Especially B-cell contribution and autoantibody-dependence are not mirrored adequately: therefore, new B-cell-dependent models, such as MP4-induced EAE, have been introduced. Furthermore, certain symptoms and the spontaneous onset of MS are not featured in classic EAE. Herein, atypical and spontaneous EAE models can be used for investigation of common symptoms, such as tremor and ataxia, as well as spontaneous disease development. MS displays a marked inter-individual heterogeneity, and no single model will be able to cover all features. Thus, depending on the objective of one's study, the appropriate EAE model has to be carefully chosen. In addition, refined models should be designed to gain a more complete understanding of MS.
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http://dx.doi.org/10.1111/j.1600-0463.2011.02794.xDOI Listing
December 2011

Emerging concepts in autoimmune encephalomyelitis beyond the CD4/T(H)1 paradigm.

Ann Anat 2010 Aug 15;192(4):179-93. Epub 2010 Jul 15.

Department of Anatomy I, University Hospitals of Cologne, Germany.

Multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) have long been regarded as primarily T helper cell type 1-mediated diseases. However, recent evidence suggests that T(H)17 cells, a mostly unexplored subset of T helper cells, may be even more pathogenic than T(H)1 cells. In the EAE model, this cell type is crucial for the recruitment of leukocytes into the CNS and for triggering parenchymal inflammation. In humans, T(H)17 cells are found in acutely active and on the borders of chronically active lesions. Overall, CD4(+) T cells only recognize antigens presented on MHC class II complexes, and these are seldom found in the CNS. MHC class I, in contrast, can be induced on neurons and myelin. This also makes CD8(+) T cells promising candidates as effector cell types. Indeed, CD8(+) T cells outnumber CD4(+) T cells in the lesions of MS patients, and can induce axonal pathology. New data on B cells have likewise stimulated unconventional paths of reasoning about the disease. B cells can contribute to the pathogenesis by secreting autoantibodies and presenting antigens to T cells. By the formation of ectopic B cell aggregates in the CNS, B cell differentiation and response can take place remote from the periphery, thus autonomously fueling pathology. In addition, cells of the innate immune system including macrophages, dendritic cells and mast cells are present in the inflamed CNS. On the one hand, these cells can recognize pathogen-associated molecular patterns via Toll-like receptors (TLRs), generating proinflammatory signals that trigger adaptive immune responses. On the other hand, these cells support the autoimmune process by the secretion of effector molecules such as nitric oxide (NO). Apart from a solely pathogenic autoimmune role, regulatory T cells, NK cells and NKT cells can suppress autoreactive cells. In this paper, we review data on how a complex network of immune mechanisms is involved in the pathogenesis of MS and EAE. We also critically reevaluate the traditional CD4/T(H)1 paradigm.
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http://dx.doi.org/10.1016/j.aanat.2010.06.006DOI Listing
August 2010