1
|
Szijj PA, Gray MA, Ribi MK, Bahou C, Nogueira JCF, Bertozzi CR, Chudasama V. Chemical generation of checkpoint inhibitory T cell engagers for the treatment of cancer. Nat Chem 2023; 15:1636-1647. [PMID: 37488375 PMCID: PMC10624612 DOI: 10.1038/s41557-023-01280-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 06/21/2023] [Indexed: 07/26/2023]
Abstract
Bispecific T cell engagers (BiTEs), a subset of bispecific antibodies (bsAbs), can promote a targeted cancer cell's death by bringing it close to a cytotoxic T cell. Checkpoint inhibitory T cell engagers (CiTEs) comprise a BiTE core with an added immunomodulatory protein, which serves to reverse cancer-cell immune-dampening strategies, improving efficacy. So far, protein engineering has been the main approach to generate bsAbs and CiTEs, but improved chemical methods for their generation have recently been developed. Homogeneous fragment-based bsAbs constructed from fragment antigen-binding regions (Fabs) can be generated using click chemistry. Here we describe a chemical method to generate biotin-functionalized three-protein conjugates, which include two CiTE molecules, one containing an anti-PD-1 Fab and the other containing an immunomodulatory enzyme, Salmonella typhimurium sialidase. The CiTEs' efficacy was shown to be superior to that of the simpler BiTE scaffold, with the sialidase-containing CiTE inducing substantially enhanced T cell-mediated cytotoxicity in vitro. The chemical method described here, more generally, enables the generation of multi-protein constructs with further biological applications.
Collapse
Affiliation(s)
- Peter A Szijj
- Department of Chemistry, University College London, London, UK
| | - Melissa A Gray
- Department of Chemistry, Sarafan ChEM-H, and Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Mikaela K Ribi
- Department of Chemistry, Sarafan ChEM-H, and Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Calise Bahou
- Department of Chemistry, University College London, London, UK
| | | | - Carolyn R Bertozzi
- Department of Chemistry, Sarafan ChEM-H, and Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
| | - Vijay Chudasama
- Department of Chemistry, University College London, London, UK.
| |
Collapse
|
2
|
Hollander MJ, Malaker SA, Riley NM, Perez I, Abney NM, Gray MA, Maxson JE, Cochran JR, Bertozzi CR. Mutational screens highlight glycosylation as a modulator of colony-stimulating factor 3 receptor (CSF3R) activity. J Biol Chem 2023; 299:104755. [PMID: 37116708 PMCID: PMC10245049 DOI: 10.1016/j.jbc.2023.104755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 04/21/2023] [Accepted: 04/23/2023] [Indexed: 04/30/2023] Open
Abstract
The colony-stimulating factor 3 receptor (CSF3R) controls the growth of neutrophils, the most abundant type of white blood cell. In healthy neutrophils, signaling is dependent on CSF3R binding to its ligand, CSF3. A single amino acid mutation in CSF3R, T618I, instead allows for constitutive, ligand-independent cell growth and leads to a rare type of cancer called chronic neutrophilic leukemia. However, the disease mechanism is not well understood. Here, we investigated why this threonine to isoleucine substitution is the predominant mutation in chronic neutrophilic leukemia and how it leads to uncontrolled neutrophil growth. Using protein domain mapping, we demonstrated that the single CSF3R domain containing residue 618 is sufficient for ligand-independent activity. We then applied an unbiased mutational screening strategy focused on this domain and found that activating mutations are enriched at sites normally occupied by asparagine, threonine, and serine residues-the three amino acids which are commonly glycosylated. We confirmed glycosylation at multiple CSF3R residues by mass spectrometry, including the presence of GalNAc and Gal-GalNAc glycans at WT threonine 618. Using the same approach applied to other cell surface receptors, we identified an activating mutation, S489F, in the interleukin-31 receptor alpha chain. Combined, these results suggest a role for glycosylated hotspot residues in regulating receptor signaling, mutation of which can lead to ligand-independent, uncontrolled activity and human disease.
Collapse
Affiliation(s)
- Michael J Hollander
- Department of Bioengineering, Stanford University, Stanford, California, USA; Department of Chemistry and Sarafan ChEM-H, Stanford University, Stanford, California, USA
| | - Stacy A Malaker
- Department of Chemistry and Sarafan ChEM-H, Stanford University, Stanford, California, USA
| | - Nicholas M Riley
- Department of Chemistry and Sarafan ChEM-H, Stanford University, Stanford, California, USA
| | - Idalia Perez
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Nayla M Abney
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Melissa A Gray
- Department of Chemistry and Sarafan ChEM-H, Stanford University, Stanford, California, USA
| | - Julia E Maxson
- Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Jennifer R Cochran
- Department of Bioengineering, Stanford University, Stanford, California, USA; Department of Chemical Engineering, Stanford University, Stanford, California, USA.
| | - Carolyn R Bertozzi
- Department of Chemistry and Sarafan ChEM-H, Stanford University, Stanford, California, USA; Howard Hughes Medical Institute, Stanford, California, USA.
| |
Collapse
|
3
|
Stanczak MA, Mantuano NR, Kirchhammer N, Sanin DE, Jacob F, Coelho R, Everest-Dass AV, Wang J, Trefny MP, Monaco G, Bärenwaldt A, Gray MA, Petrone A, Kashyap AS, Glatz K, Kasenda B, Normington K, Broderick J, Peng L, Pearce OM, Pearce EL, Bertozzi CR, Zippelius A, Läubli H. Targeting cancer glycosylation repolarizes tumor-associated macrophages allowing effective immune checkpoint blockade. Sci Transl Med 2022; 14:eabj1270. [PMID: 36322632 PMCID: PMC9812757 DOI: 10.1126/scitranslmed.abj1270] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Immune checkpoint blockade (ICB) has substantially improved the prognosis of patients with cancer, but the majority experiences limited benefit, supporting the need for new therapeutic approaches. Up-regulation of sialic acid-containing glycans, termed hypersialylation, is a common feature of cancer-associated glycosylation, driving disease progression and immune escape through the engagement of Siglec receptors on tumor-infiltrating immune cells. Here, we show that tumor sialylation correlates with distinct immune states and reduced survival in human cancers. The targeted removal of Siglec ligands in the tumor microenvironment, using an antibody-sialidase conjugate, enhanced antitumor immunity and halted tumor progression in several murine models. Using single-cell RNA sequencing, we revealed that desialylation repolarized tumor-associated macrophages (TAMs). We also identified Siglec-E as the main receptor for hypersialylation on TAMs. Last, we found that genetic and therapeutic desialylation, as well as loss of Siglec-E, enhanced the efficacy of ICB. Thus, therapeutic desialylation represents an immunotherapeutic approach to reshape macrophage phenotypes and augment the adaptive antitumor immune response.
Collapse
Affiliation(s)
- Michal A. Stanczak
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland
- Bloomberg-Kimmel Institute for Cancer Immunotherapy at Johns Hopkins, Baltimore, MD 21287, USA
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany
| | | | - Nicole Kirchhammer
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland
| | - David E. Sanin
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany
| | - Francis Jacob
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland
| | - Ricardo Coelho
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland
| | - Arun V. Everest-Dass
- Institute for Glycomics, Griffith University, Gold Coast Campus, Gold Coast QLD4222, Australia
| | - Jinyu Wang
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland
| | - Marcel P. Trefny
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland
| | - Gianni Monaco
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland
| | - Anne Bärenwaldt
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland
| | - Melissa A. Gray
- Department of Chemistry, Stanford ChEM-H, and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | | | - Abhishek S. Kashyap
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland
| | - Katharina Glatz
- Institute of Pathology, University Hospital Basel, 4031 Basel, Switzerland
| | - Benjamin Kasenda
- Division of Oncology, Department of Theragnostics, University Hospital Basel, 4031 Basel, Switzerland
| | | | | | - Li Peng
- Palleon Pharmaceuticals, Waltham, MA 02451, USA
| | - Oliver M.T. Pearce
- Centre for Tumour Microenvironment, Barts Cancer Institute, Queen Mary University, London EC1M 6BQ, UK
| | - Erika L. Pearce
- Bloomberg-Kimmel Institute for Cancer Immunotherapy at Johns Hopkins, Baltimore, MD 21287, USA
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany
| | - Carolyn R. Bertozzi
- Department of Chemistry, Stanford ChEM-H, and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Alfred Zippelius
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland
- Division of Oncology, Department of Theragnostics, University Hospital Basel, 4031 Basel, Switzerland
| | - Heinz Läubli
- Department of Biomedicine, University Hospital and University of Basel, 4031 Basel, Switzerland
- Division of Oncology, Department of Theragnostics, University Hospital Basel, 4031 Basel, Switzerland
| |
Collapse
|
4
|
Amatngalim GD, Rodenburg LW, Delpiano L, Smits SMA, Aalbers BL, van der Ent CK, Gray MA, Beekman JM. WS16.05 Identification of drugs activating CFTR-independent fluid secretion in nasal organoids based on a high-content screening assay. J Cyst Fibros 2022. [DOI: 10.1016/s1569-1993(22)00247-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
5
|
Meyer F, Fritz A, Deng ZL, Koslicki D, Lesker TR, Gurevich A, Robertson G, Alser M, Antipov D, Beghini F, Bertrand D, Brito JJ, Brown CT, Buchmann J, Buluç A, Chen B, Chikhi R, Clausen PTLC, Cristian A, Dabrowski PW, Darling AE, Egan R, Eskin E, Georganas E, Goltsman E, Gray MA, Hansen LH, Hofmeyr S, Huang P, Irber L, Jia H, Jørgensen TS, Kieser SD, Klemetsen T, Kola A, Kolmogorov M, Korobeynikov A, Kwan J, LaPierre N, Lemaitre C, Li C, Limasset A, Malcher-Miranda F, Mangul S, Marcelino VR, Marchet C, Marijon P, Meleshko D, Mende DR, Milanese A, Nagarajan N, Nissen J, Nurk S, Oliker L, Paoli L, Peterlongo P, Piro VC, Porter JS, Rasmussen S, Rees ER, Reinert K, Renard B, Robertsen EM, Rosen GL, Ruscheweyh HJ, Sarwal V, Segata N, Seiler E, Shi L, Sun F, Sunagawa S, Sørensen SJ, Thomas A, Tong C, Trajkovski M, Tremblay J, Uritskiy G, Vicedomini R, Wang Z, Wang Z, Wang Z, Warren A, Willassen NP, Yelick K, You R, Zeller G, Zhao Z, Zhu S, Zhu J, Garrido-Oter R, Gastmeier P, Hacquard S, Häußler S, Khaledi A, Maechler F, Mesny F, Radutoiu S, Schulze-Lefert P, Smit N, Strowig T, Bremges A, Sczyrba A, McHardy AC. Critical Assessment of Metagenome Interpretation: the second round of challenges. Nat Methods 2022; 19:429-440. [PMID: 35396482 PMCID: PMC9007738 DOI: 10.1038/s41592-022-01431-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 02/14/2022] [Indexed: 12/20/2022]
Abstract
Evaluating metagenomic software is key for optimizing metagenome interpretation and focus of the Initiative for the Critical Assessment of Metagenome Interpretation (CAMI). The CAMI II challenge engaged the community to assess methods on realistic and complex datasets with long- and short-read sequences, created computationally from around 1,700 new and known genomes, as well as 600 new plasmids and viruses. Here we analyze 5,002 results by 76 program versions. Substantial improvements were seen in assembly, some due to long-read data. Related strains still were challenging for assembly and genome recovery through binning, as was assembly quality for the latter. Profilers markedly matured, with taxon profilers and binners excelling at higher bacterial ranks, but underperforming for viruses and Archaea. Clinical pathogen detection results revealed a need to improve reproducibility. Runtime and memory usage analyses identified efficient programs, including top performers with other metrics. The results identify challenges and guide researchers in selecting methods for analyses. This study presents the results of the second round of the Critical Assessment of Metagenome Interpretation challenges (CAMI II), which is a community-driven effort for comprehensively benchmarking tools for metagenomics data analysis.
Collapse
Affiliation(s)
- Fernando Meyer
- Computational Biology of Infection Research, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - Adrian Fritz
- Computational Biology of Infection Research, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany.,German Center for Infection Research (DZIF), Hannover-Braunschweig Site, Braunschweig, Germany
| | - Zhi-Luo Deng
- Computational Biology of Infection Research, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany.,Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | | | - Till Robin Lesker
- German Center for Infection Research (DZIF), Hannover-Braunschweig Site, Braunschweig, Germany.,Helmholtz Centre for Infection Research, Braunschweig, Germany
| | | | - Gary Robertson
- Computational Biology of Infection Research, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - Mohammed Alser
- Department of Information Technology and Electrical Engineering, ETH Zürich, Zurich, Switzerland
| | - Dmitry Antipov
- Center for Algorithmic Biotechnology, Saint Petersburg State University, Saint Petersburg, Russia
| | | | | | | | | | - Jan Buchmann
- Institute for Biological Data Science, Heinrich-Heine-University, Düsseldorf, Germany
| | - Aydin Buluç
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,University of California, Berkeley, Berkeley, CA, USA
| | - Bo Chen
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,University of California, Berkeley, Berkeley, CA, USA
| | | | - Philip T L C Clausen
- National Food Institute, Division of Global Surveillance, Technical University of Denmark, Lyngby, Denmark
| | - Alexandru Cristian
- Drexel University, Philadelphia, PA, USA.,Google Inc., Philadelphia, PA, USA
| | - Piotr Wojciech Dabrowski
- Robert Koch-Institut, Berlin, Germany.,Hochschule für Technik und Wirtschaft Berlin, Berlin, Germany
| | | | - Rob Egan
- DOE Joint Genome Institute, Berkeley, CA, USA.,Lawrence Berkeley National Laboratories, Berkeley, CA, USA
| | - Eleazar Eskin
- University of California, Los Angeles, Los Angeles, CA, USA
| | | | - Eugene Goltsman
- DOE Joint Genome Institute, Berkeley, CA, USA.,Lawrence Berkeley National Laboratories, Berkeley, CA, USA
| | - Melissa A Gray
- Drexel University, Philadelphia, PA, USA.,Ecological and Evolutionary Signal-Processing and Informatics Laboratory, Philadelphia, PA, USA
| | - Lars Hestbjerg Hansen
- University of Copenhagen, Department of Plant and Environmental Science, Frederiksberg, Denmark
| | - Steven Hofmeyr
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,University of California, Berkeley, Berkeley, CA, USA
| | - Pingqin Huang
- School of Computer Science, Fudan University, Shanghai, China
| | - Luiz Irber
- University of California, Davis, Davis, CA, USA
| | - Huijue Jia
- BGI-Shenzhen, Shenzhen, China.,Shenzhen Key Laboratory of Human Commensal Microorganisms and Health Research, BGI-Shenzhen, Shenzhen, China
| | - Tue Sparholt Jørgensen
- Technical University of Denmark, Novo Nordisk Foundation Center for Biosustainability, Lyngby, Denmark.,Aarhus University, Department of Environmental Science, Roskilde, Denmark
| | - Silas D Kieser
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Swiss Institute of Bioinformatics, Geneva, Switzerland
| | | | - Axel Kola
- Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Mikhail Kolmogorov
- Department of Computer Science and Engineering, University of California San Diego, San Diego, CA, USA
| | - Anton Korobeynikov
- Center for Algorithmic Biotechnology, Saint Petersburg State University, Saint Petersburg, Russia.,Department of Statistical Modelling, Saint Petersburg State University, Saint Petersburg, Russia
| | - Jason Kwan
- University of Wisconsin-Madison, Madison, WI, USA
| | | | | | - Chenhao Li
- Genome Institute of Singapore, Singapore, Singapore
| | | | - Fabio Malcher-Miranda
- Hasso Plattner Institute, Digital Engineering Faculty, University of Potsdam, Potsdam, Germany
| | | | - Vanessa R Marcelino
- Sydney Medical School, The University of Sydney, Sydney, Australia.,Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Australia
| | | | - Pierre Marijon
- Department of Computer Science, Inria, University of Lille, CNRS, Lille, France
| | - Dmitry Meleshko
- Center for Algorithmic Biotechnology, Saint Petersburg State University, Saint Petersburg, Russia
| | - Daniel R Mende
- Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Alessio Milanese
- Department of Biology, Institute of Microbiology and Swiss Institute of Bioinformatics, ETH Zürich, Zürich, Switzerland.,Structural and Computational Biology Unit, EMBL, Heidelberg, Germany
| | - Niranjan Nagarajan
- Genome Institute of Singapore, A*STAR, Singapore, Singapore.,National University of Singapore, Singapore, Singapore
| | | | - Sergey Nurk
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Leonid Oliker
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,University of California, Berkeley, Berkeley, CA, USA
| | - Lucas Paoli
- Department of Biology, Institute of Microbiology and Swiss Institute of Bioinformatics, ETH Zürich, Zürich, Switzerland
| | | | - Vitor C Piro
- Hasso Plattner Institute, Digital Engineering Faculty, University of Potsdam, Potsdam, Germany
| | | | - Simon Rasmussen
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Evan R Rees
- University of Wisconsin-Madison, Madison, WI, USA
| | - Knut Reinert
- Institute for Bioinformatics, FU Berlin, Berlin, Germany
| | - Bernhard Renard
- Hasso Plattner Institute, Digital Engineering Faculty, University of Potsdam, Potsdam, Germany.,Bioinformatics Unit (MF1), Robert Koch Institute, Berlin, Germany
| | | | - Gail L Rosen
- Drexel University, Philadelphia, PA, USA.,Ecological and Evolutionary Signal-Processing and Informatics Laboratory, Philadelphia, PA, USA.,Center for Biological Discovery from Big Data, Philadelphia, PA, USA
| | - Hans-Joachim Ruscheweyh
- Department of Biology, Institute of Microbiology and Swiss Institute of Bioinformatics, ETH Zürich, Zürich, Switzerland
| | - Varuni Sarwal
- University of California, Los Angeles, Los Angeles, CA, USA
| | - Nicola Segata
- Department CIBIO, University of Trento, Trento, Italy
| | - Enrico Seiler
- Institute for Bioinformatics, FU Berlin, Berlin, Germany
| | - Lizhen Shi
- Florida Polytechnic University, Lakeland, FL, USA
| | - Fengzhu Sun
- Quantitative and Computational Biology Department, University of Southern California, Los Angeles, CA, USA
| | - Shinichi Sunagawa
- Department of Biology, Institute of Microbiology and Swiss Institute of Bioinformatics, ETH Zürich, Zürich, Switzerland
| | | | - Ashleigh Thomas
- DOE Joint Genome Institute, Berkeley, CA, USA.,University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Mirko Trajkovski
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Diabetes Center, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Julien Tremblay
- Energy, Mining and Environment, National Research Council Canada, Montreal, Quebec, Canada
| | | | | | - Zhengyang Wang
- School of Computer Science, Fudan University, Shanghai, China
| | - Ziye Wang
- School of Mathematical Sciences, Fudan University, Shanghai, China
| | - Zhong Wang
- Department of Energy Joint Genome Institute, Berkeley, CA, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,School of Natural Sciences, University of California at Merced, Merced, CA, USA
| | | | | | - Katherine Yelick
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,University of California, Berkeley, Berkeley, CA, USA
| | - Ronghui You
- School of Computer Science, Fudan University, Shanghai, China
| | - Georg Zeller
- Structural and Computational Biology Unit, EMBL, Heidelberg, Germany
| | | | - Shanfeng Zhu
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China.,Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai, China
| | - Jie Zhu
- BGI-Shenzhen, Shenzhen, China.,Shenzhen Key Laboratory of Human Commensal Microorganisms and Health Research, BGI-Shenzhen, Shenzhen, China
| | | | | | | | - Susanne Häußler
- Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Ariane Khaledi
- Helmholtz Centre for Infection Research, Braunschweig, Germany
| | | | - Fantin Mesny
- Max Planck Institute for Plant Breeding Research, Köln, Germany
| | | | | | - Nathiana Smit
- Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Till Strowig
- Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Andreas Bremges
- Computational Biology of Infection Research, Helmholtz Centre for Infection Research, Braunschweig, Germany.,German Center for Infection Research (DZIF), Hannover-Braunschweig Site, Braunschweig, Germany
| | - Alexander Sczyrba
- Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
| | - Alice Carolyn McHardy
- Computational Biology of Infection Research, Helmholtz Centre for Infection Research, Braunschweig, Germany. .,Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany. .,German Center for Infection Research (DZIF), Hannover-Braunschweig Site, Braunschweig, Germany. .,Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany.
| |
Collapse
|
6
|
Gray MA, Stanczak MA, Mantuano NR, Xiao H, Pijnenborg JFA, Malaker SA, Miller CL, Weidenbacher PA, Tanzo JT, Ahn G, Woods EC, Läubli H, Bertozzi CR. Targeted glycan degradation potentiates the anticancer immune response in vivo. Nat Chem Biol 2020; 16:1376-1384. [PMID: 32807964 PMCID: PMC7727925 DOI: 10.1038/s41589-020-0622-x] [Citation(s) in RCA: 171] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/08/2020] [Indexed: 12/24/2022]
Abstract
Currently approved immune checkpoint inhibitor therapies targeting the PD-1 and CTLA-4 receptor pathways are powerful treatment options for certain cancers; however, most patients across cancer types still fail to respond. Consequently, there is interest in discovering and blocking alternative pathways that mediate immune suppression. One such mechanism is an upregulation of sialoglycans in malignancy, which has been recently shown to inhibit immune cell activation through multiple mechanisms and therefore represents a targetable glycoimmune checkpoint. Since these glycans are not canonically druggable, we designed an αHER2 antibody-sialidase conjugate that potently and selectively strips diverse sialoglycans from breast cancer cells. In syngeneic breast cancer models, desialylation enhanced immune cell infiltration and activation and prolonged the survival of mice, an effect that was dependent on expression of the Siglec-E checkpoint receptor found on tumor-infiltrating myeloid cells. Thus, antibody-sialidase conjugates represent a promising modality for glycoimmune checkpoint therapy.
Collapse
MESH Headings
- Allografts
- Animals
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/metabolism
- B7-H1 Antigen/genetics
- B7-H1 Antigen/immunology
- Cell Line, Tumor
- Humans
- Hydrolysis
- Immunoconjugates/chemistry
- Immunoconjugates/metabolism
- Immunoconjugates/pharmacology
- Immunotherapy/methods
- Killer Cells, Natural/cytology
- Killer Cells, Natural/immunology
- Melanoma, Experimental/genetics
- Melanoma, Experimental/immunology
- Melanoma, Experimental/mortality
- Melanoma, Experimental/therapy
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Models, Molecular
- Molecular Targeted Therapy
- Neuraminidase/chemistry
- Neuraminidase/genetics
- Neuraminidase/immunology
- Polysaccharides/chemistry
- Polysaccharides/immunology
- Programmed Cell Death 1 Receptor/genetics
- Programmed Cell Death 1 Receptor/immunology
- Protein Binding
- Protein Interaction Domains and Motifs
- Protein Structure, Secondary
- Receptor, ErbB-2/chemistry
- Receptor, ErbB-2/genetics
- Receptor, ErbB-2/immunology
- Sialic Acid Binding Immunoglobulin-like Lectins/chemistry
- Sialic Acid Binding Immunoglobulin-like Lectins/genetics
- Sialic Acid Binding Immunoglobulin-like Lectins/immunology
- Survival Analysis
- T-Lymphocytes/cytology
- T-Lymphocytes/immunology
Collapse
Affiliation(s)
- Melissa A Gray
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Michal A Stanczak
- Cancer Immunology Laboratory, Department of Biomedicine, University Hospital, Basel, Switzerland
- Division of Oncology, Department of Internal Medicine, University Hospital, Basel, Switzerland
| | - Natália R Mantuano
- Cancer Immunology Laboratory, Department of Biomedicine, University Hospital, Basel, Switzerland
- Division of Oncology, Department of Internal Medicine, University Hospital, Basel, Switzerland
| | - Han Xiao
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | | | - Stacy A Malaker
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Caitlyn L Miller
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | | | - Julia T Tanzo
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Green Ahn
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Elliot C Woods
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Heinz Läubli
- Cancer Immunology Laboratory, Department of Biomedicine, University Hospital, Basel, Switzerland
- Division of Oncology, Department of Internal Medicine, University Hospital, Basel, Switzerland
| | - Carolyn R Bertozzi
- Department of Chemistry, Stanford University, Stanford, CA, USA.
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
| |
Collapse
|
7
|
Bule P, Chuzel L, Blagova E, Wu L, Gray MA, Henrissat B, Rapp E, Bertozzi CR, Taron CH, Davies GJ. Inverting family GH156 sialidases define an unusual catalytic motif for glycosidase action. Nat Commun 2019; 10:4816. [PMID: 31645552 PMCID: PMC6811678 DOI: 10.1038/s41467-019-12684-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 09/23/2019] [Indexed: 12/17/2022] Open
Abstract
Sialic acids are a family of related sugars that play essential roles in many biological events intimately linked to cellular recognition in both health and disease. Sialidases are therefore orchestrators of cellular biology and important therapeutic targets for viral infection. Here, we sought to define if uncharacterized sialidases would provide distinct paradigms in sialic acid biochemistry. We show that a recently discovered sialidase family, whose first member EnvSia156 was isolated from hot spring metagenomes, defines an unusual structural fold and active centre constellation, not previously described in sialidases. Consistent with an inverting mechanism, EnvSia156 reveals a His/Asp active center in which the His acts as a Brønsted acid and Asp as a Brønsted base in a single-displacement mechanism. A predominantly hydrophobic aglycone site facilitates accommodation of a variety of 2-linked sialosides; a versatility that offers the potential for glycan hydrolysis across a range of biological and technological platforms.
Collapse
Affiliation(s)
- Pedro Bule
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | - Léa Chuzel
- New England Biolabs, 240 County Road, Ipswich, MA, 01938, USA
| | - Elena Blagova
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | - Liang Wu
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | - Melissa A Gray
- Department of Chemistry, Stanford University, Stanford, CA, 94305-4404, USA
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques (AFMB), Centre National de la Recherche Scientifique (CNRS, UMR7257), Institut National Agronomique (INRA, USC 1408) and Aix-Marseille Université (AMU), 13288 Marseille cedex 9, Marseille, France
| | - Erdmann Rapp
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106, Magdeburg, Germany
- glyXera GmbH, Leipziger Strasse 44-ZENIT, Magdeburg, Germany
| | - Carolyn R Bertozzi
- Department of Chemistry, Stanford University, Stanford, CA, 94305-4404, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, 94305-4404, USA
| | | | - Gideon J Davies
- Department of Chemistry, University of York, York, YO10 5DD, UK.
| |
Collapse
|
8
|
Choi J, Wagner LJS, Timmermans SBPE, Malaker SA, Schumann B, Gray MA, Debets MF, Takashima M, Gehring J, Bertozzi CR. Engineering Orthogonal Polypeptide GalNAc-Transferase and UDP-Sugar Pairs. J Am Chem Soc 2019; 141:13442-13453. [PMID: 31373799 PMCID: PMC6813768 DOI: 10.1021/jacs.9b04695] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
O-Linked α-N-acetylgalactosamine (O-GalNAc) glycans constitute a major part of the human glycome. They are difficult to study because of the complex interplay of 20 distinct glycosyltransferase isoenzymes that initiate this form of glycosylation, the polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts). Despite proven disease relevance, correlating the activity of individual GalNAc-Ts with biological function remains challenging due to a lack of tools to probe their substrate specificity in a complex biological environment. Here, we develop a "bump-hole" chemical reporter system for studying GalNAc-T activity in vitro. Individual GalNAc-Ts were rationally engineered to contain an enlarged active site (hole) and probed with a newly synthesized collection of 20 (bumped) uridine diphosphate N-acetylgalactosamine (UDP-GalNAc) analogs to identify enzyme-substrate pairs that retain peptide specificities but are otherwise completely orthogonal to native enzyme-substrate pairs. The approach was applicable to multiple GalNAc-T isoenzymes, including GalNAc-T1 and -T2 that prefer nonglycosylated peptide substrates and GalNAcT-10 that prefers a preglycosylated peptide substrate. A detailed investigation of enzyme kinetics and specificities revealed the robustness of the approach to faithfully report on GalNAc-T activity and paves the way for studying substrate specificities in living systems.
Collapse
Affiliation(s)
- Junwon Choi
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Chemical Kinomics Research Center, Korea Institute of Science and Technology (KIST), 5 Hwarangro 14-gil, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Lauren J. S. Wagner
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Suzanne B. P. E. Timmermans
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Bio-Organic Chemistry Research Group, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, Netherlands
| | - Stacy A. Malaker
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Benjamin Schumann
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Melissa A. Gray
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Marjoke F. Debets
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Megumi Takashima
- Department of Nutritional Sciences, University of California, Berkeley, California 94720, United States
| | - Jase Gehring
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, United States
| | - Carolyn R. Bertozzi
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Howard Hughes Medical Institute, Stanford University, Stanford, California 94305, United States
| |
Collapse
|
9
|
Taylor JN, Nguyen NT, Gray MA. The Pharmacy Student Population: Applications Received 2017-18, Degrees Conferred 2017-18, Fall 2018 Enrollments. Am J Pharm Educ 2019; 83:7658. [PMID: 31507300 PMCID: PMC6718495 DOI: 10.5688/ajpe7658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Affiliation(s)
- Jamie N Taylor
- American Association of Colleges of Pharmacy, Arlington, Virginia
| | - Nancy T Nguyen
- American Association of Colleges of Pharmacy, Arlington, Virginia
| | - Melissa A Gray
- American Association of Colleges of Pharmacy, Arlington, Virginia
| |
Collapse
|
10
|
Tsai CT, Mukai K, Robinson PV, Gray MA, Waschmann MB, Lyu SC, Tsai M, Chinthrajah RS, Nadeau KC, Bertozzi CR, Galli SJ. Isotype-specific agglutination-PCR (ISAP): A sensitive and multiplex method for measuring allergen-specific IgE. J Allergy Clin Immunol 2017; 141:1901-1904.e15. [PMID: 29248495 DOI: 10.1016/j.jaci.2017.11.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 11/15/2017] [Accepted: 11/30/2017] [Indexed: 11/18/2022]
Affiliation(s)
- Cheng-Ting Tsai
- Department of Chemistry, Stanford University School of Humanities and Sciences, Stanford, Calif
| | - Kaori Mukai
- Department of Pathology, Microbiology and Immunology, Stanford University School of Medicine, Stanford, Calif
| | | | - Melissa A Gray
- Department of Chemical Biology, Stanford University School of Medicine, Stanford, Calif
| | - Malika B Waschmann
- Department of Human Biology, Stanford University School of Humanities and Sciences, Stanford, Calif
| | - Shu-Chen Lyu
- Division of Pulmonary and Critical Care, Department of Medicine, Stanford, Calif; Sean N. Parker Center for Allergy and Asthma Research, Stanford, Calif
| | - Mindy Tsai
- Department of Pathology, Microbiology and Immunology, Stanford University School of Medicine, Stanford, Calif; Sean N. Parker Center for Allergy and Asthma Research, Stanford, Calif
| | - Rebecca S Chinthrajah
- Division of Pulmonary and Critical Care, Department of Medicine, Stanford, Calif; Sean N. Parker Center for Allergy and Asthma Research, Stanford, Calif
| | - Kari C Nadeau
- Division of Pulmonary and Critical Care, Department of Medicine, Stanford, Calif; Sean N. Parker Center for Allergy and Asthma Research, Stanford, Calif
| | - Carolyn R Bertozzi
- Department of Chemistry, Stanford University School of Humanities and Sciences, Stanford, Calif; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, Calif.
| | - Stephen J Galli
- Department of Pathology, Microbiology and Immunology, Stanford University School of Medicine, Stanford, Calif; Sean N. Parker Center for Allergy and Asthma Research, Stanford, Calif; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, Calif.
| |
Collapse
|
11
|
Gray MA, Tao RN, DePorter SM, Spiegel DA, McNaughton BR. Back Cover: A Nanobody Activation Immunotherapeutic that Selectively Destroys HER2-Positive Breast Cancer Cells (ChemBioChem 2/2016). Chembiochem 2016. [DOI: 10.1002/cbic.201500679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Melissa A. Gray
- Department of Chemistry; Colorado State University; Fort Collins CO 80523 USA
| | - Ran N. Tao
- Department of Chemistry; Yale University; 225 Prospect Street New Haven CT 06511 USA
| | - Sandra M. DePorter
- Department of Chemistry; Colorado State University; Fort Collins CO 80523 USA
| | - David A. Spiegel
- Department of Chemistry; Yale University; 225 Prospect Street New Haven CT 06511 USA
| | - Brian R. McNaughton
- Department of Chemistry; Colorado State University; Fort Collins CO 80523 USA
- Department of Biochemistry and Molecular Biology; Colorado State University; Fort Collins CT 80523 USA
| |
Collapse
|
12
|
Gray MA, Tao RN, DePorter SM, Spiegel DA, McNaughton BR. A Nanobody Activation Immunotherapeutic that Selectively Destroys HER2-Positive Breast Cancer Cells. Chembiochem 2015; 17:155-8. [PMID: 26556305 DOI: 10.1002/cbic.201500591] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Indexed: 01/18/2023]
Abstract
We report a rationally designed nanobody activation immunotherapeutic that selectively redirects anti-dinitrophenyl (anti-DNP) antibodies to the surface of HER2-positive breast cancer cells, resulting in their targeted destruction by antibody-dependent cellular cytotoxicity. As nanobodies are relatively easy to express, stable, can be humanized, and can be evolved to potently and selectively bind virtually any disease-relevant cell surface receptor, we anticipate broad utility of this therapeutic strategy.
Collapse
Affiliation(s)
- Melissa A Gray
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
| | - Ran N Tao
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT, 06511, USA
| | - Sandra M DePorter
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
| | - David A Spiegel
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT, 06511, USA
| | - Brian R McNaughton
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA. .,Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CT, 80523, USA.
| |
Collapse
|
13
|
DePorter SM, Lui I, Bruce VJ, Gray MA, Lopez-Islas M, McNaughton BR. Mutagenesis modulates the uptake efficiency, cell-selectivity, and functional enzyme delivery of a protein transduction domain. ACTA ACUST UNITED AC 2014; 10:18-23. [DOI: 10.1039/c3mb70429g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
14
|
Judák L, Hegyi P, Rakonczay Z, Maléth J, Gray MA, Venglovecz V. Ethanol and its non-oxidative metabolites profoundly inhibit CFTR function in pancreatic epithelial cells which is prevented by ATP supplementation. Pflugers Arch 2013; 466:549-62. [PMID: 23948742 DOI: 10.1007/s00424-013-1333-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 07/26/2013] [Accepted: 07/30/2013] [Indexed: 02/06/2023]
Abstract
Excessive alcohol consumption is a major cause of acute pancreatitis, but the mechanism involved is not well understood. Recent investigations suggest that pancreatic ductal epithelial cells (PDECs) help defend the pancreas from noxious agents such as alcohol. Because the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel plays a major role in PDEC physiology and mutated CFTR is often associated with pancreatitis, we tested the hypothesis that ethanol affects CFTR to impair ductal function. Electrophysiological studies on native PDECs showed that ethanol (10 and 100 mM) increased basal, but reversibly blocked, forskolin-stimulated CFTR currents. The inhibitory effect of ethanol was mimicked by its non-oxidative metabolites, palmitoleic acid ethyl ester (POAEE) and palmitoleic acid (POA), but not by the oxidative metabolite, acetaldehyde. Ethanol, POAEE and POA markedly reduced intracellular ATP (ATPi) which was linked to CFTR inhibition since the inhibitory effects were almost completely abolished if ATPi depletion was prevented. We propose that ethanol causes functional damage of CFTR through an ATPi-dependent mechanism, which compromises ductal fluid secretion and likely contributes to the pathogenesis of acute pancreatitis. We suggest that the maintenance of ATPi may represent a therapeutic option in the treatment of the disease.
Collapse
Affiliation(s)
- L Judák
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | | | | | | | | | | |
Collapse
|
15
|
DePorter SM, Hendricks NK, Gray MA, McNaughton BR. A one-pot synthesis of micron-sized and nanoscale poly(N-acryloxysuccinimide-co-N-vinylpyrrolidone) particles. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.09.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
16
|
Radulescu E, Ganeshan B, Minati L, Beacher FDCC, Gray MA, Chatwin C, Young RCD, Harrison NA, Critchley HD. Gray matter textural heterogeneity as a potential in-vivo biomarker of fine structural abnormalities in Asperger syndrome. Pharmacogenomics J 2012; 13:70-9. [DOI: 10.1038/tpj.2012.3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
17
|
Jones CL, Gray MA, Minati L, Simner J, Critchley HD, Ward J. The neural basis of illusory gustatory sensations: two rare cases of lexical-gustatory synaesthesia. J Neuropsychol 2012; 5:243-54. [PMID: 21923788 DOI: 10.1111/j.1748-6653.2011.02013.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lexical-gustatory synaesthesia is a rare phenomenon in which the individual experiences flavour sensations when they read, hear, or imagine words. In this study, we provide insight into the neural basis of this form of synaesthesia using functional neuroimaging. Words known to evoke pleasant, neutral, and unpleasant synaesthetic tastes and synaesthetically tasteless words were presented to two lexical-gustatory synaesthetes, during fMRI scanning. Ten non-synaesthetic participants were also scanned on the same list of words. The synaesthetic brain displayed a different pattern of activity to words when compared to the non-synaesthetes, with insula activation related to viewing words that elicited tastes that have an associated emotional valence (i.e., pleasant or unpleasant tastes). The subjective intensity of the synaesthesia was correlated with activity in the medial parietal lobes (precuneus/retrosplenial cortex), which are implicated in polymodal imagery and self-directed thought. This region has also previously been activated in studies of lexical-colour synaesthesia, suggesting its role may not be limited to the type of synaesthesia explored here.
Collapse
Affiliation(s)
- C L Jones
- Psychiatry, Brighton and Sussex Medical School, UK.
| | | | | | | | | | | |
Collapse
|
18
|
Beacher FD, Minati L, Baron-Cohen S, Lombardo MV, Lai MC, Gray MA, Harrison NA, Critchley HD. Autism attenuates sex differences in brain structure: a combined voxel-based morphometry and diffusion tensor imaging study. AJNR Am J Neuroradiol 2011; 33:83-9. [PMID: 22173769 DOI: 10.3174/ajnr.a2880] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND PURPOSE It has been proposed that autism spectrums condition may represent a form of extreme male brain (EMB), a notion supported by psychometric, behavioral, and endocrine evidence. Yet, limited data are presently available evaluating this hypothesis in terms of neuroanatomy. Here, we investigated sex-related anatomic features in adults with AS, a "pure" form of autism not involving major developmental delay. MATERIALS AND METHODS Males and females with AS and healthy controls (n = 28 and 30, respectively) were recruited. Structural MR imaging was performed to measure overall gray and white matter volume and to assess regional effects by means of VBM. DTI was used to investigate the integrity of the main white matter tracts. RESULTS Significant interactions were found between sex and diagnosis in total white matter volume, regional gray matter volume in the right parietal operculum, and fractional anisotropy (FA) in the body of the CC, cingulum, and CR. Post hoc comparisons indicated that the typical sexual dimorphism found in controls, whereby males have larger FA and total white matter volume, was absent or attenuated in participants with AS. CONCLUSIONS Our results point to a fundamental role of the factors that underlie sex-specific brain differentiation in the etiology of autism.
Collapse
Affiliation(s)
- F D Beacher
- Department of Psychiatry and Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, Falmer, UK
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Venglovecz V, Rakonczay Z, Ozsvári B, Takács T, Lonovics J, Varró A, Gray MA, Argent BE, Hegyi P. Effects of bile acids on pancreatic ductal bicarbonate secretion in guinea pig. Gut 2008; 57:1102-12. [PMID: 18303091 DOI: 10.1136/gut.2007.134361] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
BACKGROUND AND AIMS Acute pancreatitis is associated with significant morbidity and mortality. Bile reflux into the pancreas is a common cause of acute pancreatitis and, although the bile can reach both acinar and ductal cells, most research to date has focused on the acinar cells. The aim of the present study was to investigate the effects of bile acids on HCO(3)(-) secretion from the ductal epithelium. METHODS Isolated guinea pig intralobular/interlobular pancreatic ducts were microperfused and the effects of unconjugated chenodeoxycholate (CDC) and conjugated glycochenodeoxycholate (GCDC) on intracellular calcium concentration ([Ca(2+)](i)) and pH (pH(i)) were measured using fluorescent dyes. Changes of pH(i) were used to calculate the rates of acid/base transport across the duct cell membranes. RESULTS Luminal administration of a low dose of CDC (0.1 mM) stimulated ductal HCO(3)(-) secretion, which was blocked by luminal H(2)DIDS (dihydro-4,4'-diisothiocyanostilbene-2,2'-disulfonic acid). In contrast, both luminal and basolateral administration of a high dose of CDC (1 mM) strongly inhibited HCO(3)(-) secretion. Both CDC and GCDC elevated [Ca(2+)](i), and this effect was blocked by BAPTA-AM (1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid), caffeine, xestospongin C and the phospholipase C inhibitor U73122. BAPTA-AM also inhibited the stimulatory effect of low doses of CDC on HCO(3)(-) secretion, but did not modulate the inhibitory effect of high doses of CDC. CONCLUSIONS It is concluded that the HCO(3)(-) secretion stimulated by low concentrations of bile acids acts to protect the pancreas against toxic bile, whereas inhibition of HCO(3)(-) secretion by high concentrations of bile acids may contribute to the progression of acute pancreatitis.
Collapse
Affiliation(s)
- V Venglovecz
- First Department of Medicine, University of Szeged, Szeged, Hungary
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Pirie ES, Gray MA. Exploring the assessors' and nurses' experience of formal assessment of clinical competency in the administration of blood components. Nurse Educ Pract 2007; 7:215-27. [PMID: 17689447 DOI: 10.1016/j.nepr.2006.08.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Revised: 08/23/2006] [Accepted: 08/23/2006] [Indexed: 10/24/2022]
Abstract
Blood transfusion, clinical competency, assessment, evaluation The change in nurse education from apprenticeship training to the higher education setting, has raised concerns about the lack of practical skills newly qualified nurses have on registration. Every practitioner must be able to administer blood components safely however, the Serious Hazards of Transfusion (SHOT) scheme have consistently demonstrated that 'wrong blood' incidents are the major cause of morbidity and mortality related to transfusion in the United Kingdom. As a result the SHOT working group have recommended that all practitioners should have their clinical competency formally assessed. This paper describes the development and evaluation of a tool for assessing clinical competency for staff involved in transfusing blood. The evaluation used a triangulated approach of phenomenology and survey. The tool was piloted in two different clinical settings by four registered nurses who each assessed two nurses. Individual semi-structured interviews were conducted to collate the nurses' and the assessors' experience of the process. The study participants were of the opinion that assessing clinical competency using a criterion-referenced tool gave practitioners the opportunity to relate theory to practice, promote best practice and encourage adherence to hospital transfusion policies. Formal assessment of clinical competency is therefore, a vehicle that could be used to promote safe transfusion practice, ensuring the safety of patients is paramount.
Collapse
Affiliation(s)
- E S Pirie
- Transfusion Nurse Specialist, Effective Use of Blood Group, Scottish National Blood Transfusion Service, 21 Ellen's Glen Road, Edinburgh EH17 7QT, Scotland, United Kingdom.
| | | |
Collapse
|
21
|
Ferrari S, Griesenbach U, Iida A, Farley R, Wright AM, Zhu J, Munkonge FM, Smith SN, You J, Ban H, Inoue M, Chan M, Singh C, Verdon B, Argent BE, Wainwright B, Jeffery PK, Geddes DM, Porteous DJ, Hyde SC, Gray MA, Hasegawa M, Alton EWFW. Sendai virus-mediated CFTR gene transfer to the airway epithelium. Gene Ther 2007; 14:1371-9. [PMID: 17597790 DOI: 10.1038/sj.gt.3302991] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The potential for gene therapy to be an effective treatment for cystic fibrosis has been hampered by the limited gene transfer efficiency of current vectors. We have shown that recombinant Sendai virus (SeV) is highly efficient in mediating gene transfer to differentiated airway epithelial cells, because of its capacity to overcome the intra- and extracellular barriers known to limit gene delivery. Here, we have identified a novel method to allow the cystic fibrosis transmembrane conductance regulator (CFTR) cDNA sequence to be inserted within SeV (SeV-CFTR). Following in vitro transduction with SeV-CFTR, a chloride-selective current was observed using whole-cell and single-channel patch-clamp techniques. SeV-CFTR administration to the nasal epithelium of cystic fibrosis (CF) mice (Cftr(G551D) and Cftr(tm1Unc)TgN(FABPCFTR)#Jaw mice) led to partial correction of the CF chloride transport defect. In addition, when compared to a SeV control vector, a higher degree of inflammation and epithelial damage was found in the nasal epithelium of mice treated with SeV-CFTR. Second-generation transmission-incompetent F-deleted SeV-CFTR led to similar correction of the CF chloride transport defect in vivo as first-generation transmission-competent vectors. Further modifications to the vector or the host may make it easier to translate these studies into clinical trials of cystic fibrosis.
Collapse
Affiliation(s)
- S Ferrari
- Department of Gene Therapy, Faculty of Medicine, Imperial College, National Heart and Lung Institute, London, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Linley JE, Simmons NL, Gray MA. Extracellular zinc stimulates a calcium-activated chloride conductance through mobilisation of intracellular calcium in renal inner medullary collecting duct cells. Pflugers Arch 2006; 453:487-95. [PMID: 17021797 DOI: 10.1007/s00424-006-0139-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Revised: 07/13/2006] [Accepted: 07/18/2006] [Indexed: 10/24/2022]
Abstract
We have used the perforated patch clamp and fura-2 fluorescence techniques to study the effect of extracellular Zn(2+) on whole-cell Ca(2+)-activated Cl(-) currents (I (CLCA)) in mouse inner medullary collecting duct cells (mIMCD-3). I (CLCA) was spontaneously active in 74% of cells under basal conditions and displayed time and voltage-independent kinetics and an outwardly rectifying current/voltage relationship (I/V). Addition of zinc chloride (10-400 microM) to the bathing solution resulted in a dose-dependent increase in I (CLCA) with little change in Cl(-) selectivity or biophysical characteristics, whereas gadolinium chloride (30 microM) and lanthanum chloride (100 microM) had no significant effect on the whole-cell current. Using fura-2-loaded mIMCD-3 cells, extracellular Zn(2+) (400 microM) stimulated an increase in intracellular Ca(2+) to an elevated plateau. The Zn(2+)-stimulated [Ca(2+)](i) increase was inhibited by thapsigargin (200 nM), the IP(3) receptor antagonist 2-aminoethoxydiphenyl borate (10 microM) and removal of bath Ca(2+). Pre-exposure to Zn(2+) (400 microM) markedly attenuated the ATP (100 microM)-stimulated [Ca(2+)](i) increase. These data are consistent with the hypothesis that extracellular Zn(2+) stimulates an increase in [Ca(2+)](i) by a release of calcium from thapsigargin/IP(3) sensitive stores. A possible physiological role for a divalent metal ion receptor, distinct from the extracellular Ca(2+)-sensing receptor, in IMCD cells is discussed.
Collapse
Affiliation(s)
- J E Linley
- Institute of Cell and Molecular Biosciences, University Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | | | | |
Collapse
|
23
|
Gray MA. Primary cilia and regulation of renal Na+ transport. Focus on "Heightened epithelial Na+ channel-mediated Na+ absorption in a murine polycystic kidney disease model epithelium lacking apical monocilia". Am J Physiol Cell Physiol 2006; 290:C947-9. [PMID: 16531571 DOI: 10.1152/ajpcell.00640.2005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
|
24
|
Gray MA, Peake SJ, Farrell AP, Bruch R. Acute didecyl dimethyl ammonium chloride toxicity to larval lake sturgeon, Acipenser fulvescens Rafinesque, walleye Sander vitreus Mitchill, and northern pike, Esox lucius Linnaeus. Bull Environ Contam Toxicol 2005; 75:890-6. [PMID: 16400575 DOI: 10.1007/s00128-005-0833-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2005] [Accepted: 08/26/2005] [Indexed: 05/06/2023]
Affiliation(s)
- M A Gray
- Canadian Rivers Institute and Department of Zoology, University of Manitoba, Winnipeg, Manitoba, Canada
| | | | | | | |
Collapse
|
25
|
Cunjak RA, Roussel JM, Gray MA, Dietrich JP, Cartwright DF, Munkittrick KR, Jardine TD. Using stable isotope analysis with telemetry or mark-recapture data to identify fish movement and foraging. Oecologia 2005; 144:636-46. [PMID: 15959824 DOI: 10.1007/s00442-005-0101-9] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Accepted: 03/11/2005] [Indexed: 11/25/2022]
Abstract
Information about animal movements has often been inferred from stable isotope analysis (SIA), but is dependent on animals assimilating site-specific isotopic signatures via diet. This potential weakness in ecological interpretation can be overcome by using other investigative tools that provide precise information about individual movement patterns. In this paper, we demonstrate the value of combining SIA with telemetry or mark-recapture data from trapping, electrofishing and remote detection of individuals to study the movement and feeding ecology of fishes in different habitats. In a fjord lake system in Newfoundland, Canada, juvenile Atlantic salmon delayed downstream migration (smolts) or actively moved into a large lake (parr) where they foraged for periods reflecting different life history strategies. In the Miramichi River (New Brunswick, Canada), SIA provided evidence of distinct foraging habitats (tributary versus large river). By tracking fish implanted with passive integrated transponder (PIT) tags, we distinguished between movements related to foraging versus seeking cool water refugia during high temperature events. Finally, site fidelity and limited mobility of slimy sculpin, a small benthic fish, was established where delta13C in muscle tissue showed a progressive enrichment downstream and where a median displacement of <10 m was estimated for sculpin tagged with PIT tags. Technological improvements have permitted non-destructive tissue sampling of wild fishes for SIA, and the tagging and remote detection of animals smaller than was previously possible. These advancements and the combination of investigative tools promise new insights into animal ecology.
Collapse
Affiliation(s)
- R A Cunjak
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, P.O. Box 4400, Fredericton, NB, Canada, E3B 5A3.
| | | | | | | | | | | | | |
Collapse
|
26
|
Boese SH, Aziz O, Simmons NL, Gray MA. Kinetics and regulation of a Ca2+-activated Cl- conductance in mouse renal inner medullary collecting duct cells. Am J Physiol Renal Physiol 2003; 286:F682-92. [PMID: 14678946 DOI: 10.1152/ajprenal.00123.2003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Using the whole cell patch-clamp technique, a Ca2+-activated Cl- conductance (CaCC) was transiently activated by extracellular ATP (100 microM) in primary cultures of mouse inner medullary collecting duct (IMCD) cells and in the mouse IMCD-K2 cell line. ATP also transiently increased intracellular Ca2+ concentration ([Ca2+]i) from 100 nM to peak values of approximately 750 nM in mIMCD-K2 cells, with a time course similar to the ATP-induced activation and decay of the CaCC. Removal of extracellular Ca2+ had no major effect on the peak Cl- conductance or the increase in [Ca2+]i induced by ATP, suggesting that Ca2+ released from intracellular stores directly activates the CaCC. In mIMCD-K2 cells, a rectifying time- and voltage-dependent current was observed when [Ca2+]i was fixed via the patch pipette to between 100 and 500 nM. Maximal activation occurred at approximately 1 microM [Ca2+]i, with currents losing any kinetics and displaying a linear current-voltage relationship. From Ca2+-dose-response curves, an EC50 value of approximately 650 nM at -80 mV was obtained, suggesting that under physiological conditions the CaCC would be near fully activated by mucosal nucleotides. Noise analysis of whole cell currents in mIMCD-K2 cells suggests a single-channel conductance of 6-8 pS and a density of approximately 5,000 channels/cell. In conclusion, the CaCC in mouse IMCD cells is a low-conductance, nucleotide-sensitive Cl- channel, whose activity is tightly coupled to changes in [Ca2+]i over the normal physiological range.
Collapse
Affiliation(s)
- S H Boese
- School of Cell and Molecular Bioscience, Univ. Medical School, Newcastle Upon Tyne, NE2 4HH, UK
| | | | | | | |
Collapse
|
27
|
Kemp AH, Gray MA, Eide P, Silberstein RB, Nathan PJ. Steady-state visually evoked potential topography during processing of emotional valence in healthy subjects. Neuroimage 2002; 17:1684-92. [PMID: 12498742 DOI: 10.1006/nimg.2002.1298] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The International Affective Picture System (IAPS) is increasingly used in brain imaging studies to examine emotional processes. This task allows valence and arousal content to be systematically investigated; however, previous studies have generally failed to select images that vary in one dimension as well as hold constant the variability on the other dimension. In addition, no studies have investigated the temporal structure associated with the conscious, ongoing processing of emotional stimuli following systematic selection of IAPS images. The aim of the present study was therefore to use steady-state probe topography (SSPT) to examine the steady-state visually evoked potentials (SSVEPs) associated with the processing of pleasant and unpleasant images low in arousal content. Seventy-five IAPS images, categorized as unpleasant, neutral, or pleasant, were presented to 16 healthy subjects while brain activity was recorded from 64 scalp sites. Analysis subtracted the activity associated with the presentation of neutral images from the activity associated with the presentation of pleasant as well as unpleasant images. Results demonstrate that both pleasant and unpleasant valence is associated with transient, widespread, and bilateral frontal SSVEP latency reductions. Unpleasant images were also associated with a transient bilateral anterior frontal amplitude decrease. Latency reductions are interpreted as increases in neural information processing speed, while amplitude reductions are interpreted in the current paper as analogous to an event-related desynchronisation commonly associated with the alpha bandwidth. These key findings support previous literature in terms of there being substantial overlap in frontal neural circuitry when the brain processes pleasant and unpleasant valence relative to neutral valence.
Collapse
Affiliation(s)
- A H Kemp
- Brain Sciences Institute, Swinburne University of Technology, 400 Burwood Road, Hawthorn VIC 3122, Australia
| | | | | | | | | |
Collapse
|
28
|
Gray MA. Designer pharmacotherapy for the treatment of cystic fibrosis: commentary on Zegarra-Moran et al. Br J Pharmacol 2002; 137:411-2. [PMID: 12359621 PMCID: PMC1573509 DOI: 10.1038/sj.bjp.0704883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- M A Gray
- Department of Physiological Sciences, University Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
| |
Collapse
|
29
|
Dormer RL, Dérand R, McNeilly CM, Mettey Y, Bulteau-Pignoux L, Métayé T, Vierfond JM, Gray MA, Galietta LJ, Morris MR, Pereira MM, Doull IJ, Becq F, McPherson MA. Correction of delF508-CFTR activity with benzo(c)quinolizinium compounds through facilitation of its processing in cystic fibrosis airway cells. J Cell Sci 2001; 114:4073-81. [PMID: 11739639 DOI: 10.1242/jcs.114.22.4073] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A number of genetic diseases, including cystic fibrosis, have been identified as disorders of protein trafficking associated with retention of mutant protein within the endoplasmic reticulum. In the presence of the benzo(c)quinolizinium drugs, MPB-07 and its congener MPB-91, we show the activation of cystic fibrosis transmembrane conductance regulator (CFTR) delF508 channels in IB3-1 human cells, which express endogenous levels of delF508-CFTR. These drugs were without effect on the Ca2+-activated Cl– transport, whereas the swelling-activated Cl– transport was found altered in MPB-treated cells. Immunoprecipitation and in vitro phosphorylation shows a 20% increase of the band C form of delF508 after MPB treatment. We then investigated the effect of these drugs on the extent of mislocalisation of delF508-CFTR in native airway cells from cystic fibrosis patients. We first showed that delF508 CFTR was characteristically restricted to an endoplasmic reticulum location in approximately 80% of untreated cells from CF patients homozygous for the delF508-CFTR mutation. By contrast, 60-70% of cells from non-CF patients showed wild-type CFTR in an apical location. MPB-07 treatment caused dramatic relocation of delF508-CFTR to the apical region such that the majority of delF508/delF508 CF cells showed a similar CFTR location to that of wild-type. MPB-07 had no apparent effect on the distribution of wild-type CFTR, the apical membrane protein CD59 or the ER membrane Ca2+,Mg-ATPase. We also showed a similar pharmacological effect in nasal cells freshly isolated from a delF508/G551D CF patient. The results demonstrate selective redirection of a mutant membrane protein using cell-permeant small molecules of the benzo(c)quinolizinium family and provide a major advance towards development of a targetted drug treatment for cystic fibrosis and other disorders of protein trafficking.
Collapse
Affiliation(s)
- R L Dormer
- Department of Medical Biochemistry, University of Wales College of Medicine, Heath Park, Cardiff, Wales CF14 4XN, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Sayer JA, Stewart GS, Boese SH, Gray MA, Pearce SH, Goodship TH, Simmons NL. The voltage-dependent Cl(-) channel ClC-5 and plasma membrane Cl(-) conductances of mouse renal collecting duct cells (mIMCD-3). J Physiol 2001; 536:769-83. [PMID: 11691871 PMCID: PMC2278912 DOI: 10.1111/j.1469-7793.2001.00769.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
1. We have tested the hypothesis that the voltage-dependent Cl(-) channel, ClC-5 functions as a plasma membrane Cl(-) conductance in renal inner medullary collecting duct cells. 2. Full-length mouse kidney ClC-5 (mClC-5) was cloned and transiently expressed in CHO-K1 cells. Fast whole-cell patch-clamp recordings confirmed that mClC-5 expression produces a voltage-dependent, strongly outwardly rectifying Cl(-) conductance that was unaffected by external DIDS. 3. Slow whole-cell recordings, using nystatin-perforated patches from transfected CHO-K1 cells, also produced voltage-dependent Cl(-) currents consistent with ClC-5 expression. However, under this recording configuration an endogenous DIDS-sensitive Ca(2+)-activated Cl(-) conductance was also evident, which appeared to be activated by green fluorescent protein (GFP) transfection. 4. A mClC-5-GFP fusion protein was transiently expressed in CHO-K1 cells; confocal laser scanning microscopy (CLSM) showed localization at the plasma membrane, consistent with patch-clamp experiments. 5. Endogenous expression of mClC-5 was demonstrated in mouse renal collecting duct cells (mIMCD-3) by RT-PCR and by immunocytochemistry. 6. Using slow whole-cell current recordings, mIMCD-3 cells displayed three biophysically distinct Cl(-)-selective currents, which were all inhibited by DIDS. However, no cells exhibited whole-cell currents that had mClC-5 characteristics. 7. Transient transfection of mIMCD-3 cells with antisense mClC-5 had no effect on the endogenous Cl(-) conductances. Transient transfection with sense mClC-5 failed to induce the Cl(-) conductance seen in CHO-K1 cells but stimulated levels of the endogenous Ca(2+)-activated Cl(-) conductance 24 h post-transfection. 8. Confocal laser scanning microscopy of mIMCD-3 cells transfected with mClC-5-GFP showed that the protein was absent from the plasma membrane and was instead localized to acidic endosomal compartments. 9. These data discount a major role for ClC-5 as a plasma membrane Cl(-) conductance in mIMCD-3 cells but suggest a role in endosomal function.
Collapse
Affiliation(s)
- J A Sayer
- Department of Physiological Sciences, Medical School, Framlington Place, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, UK
| | | | | | | | | | | | | |
Collapse
|
31
|
Sohma Y, Gray MA, Imai Y, Argent BE. 150 mM HCO3(-)--how does the pancreas do it? Clues from computer modelling of the duct cell. JOP 2001; 2:198-202. [PMID: 11875259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/17/2023]
Abstract
Cystic fibrosis (CF) takes its name from the pathological changes that occur in the pancreas. Cystic fibrosis transmembrane conductance regulator (CFTR) is highly expressed in the pancreatic ductal epithelium and plays a key role in ductal HCO(3)(-) secretion. In humans, the pancreatic duct secretes near isotonic NaHCO(3). Experimental data suggests that HCO(3)(-) secretion occurs via apical Cl(-)/HCO(3)(-) exchangers working in parallel with Cl(-) channels (CFTR and calcium activated chloride channels, CaCC). Programming the currently available experimental data into our computer model (based on network thermodynamics) shows that while the anion exchanger/Cl(-) channel mechanism will produce a relatively large volume of a HCO(3)(-)-rich fluid, it can only raise the luminal HCO(3)(-) concentration up to about 70 mM. To achieve secretion of about 150 mM NaHCO(3) it is necessary to modulate the properties of the apical membrane transporters as the secreted fluid flows down the ductal system. On the basis of our computer simulations, we propose that HCO(3)(-) secretion occurs mainly via the exchanger in duct segments near the acini (luminal HCO(3)(-) concentration up to about 70 mM), but mainly via channels further down the ductal tree (raising luminal HCO(3)(-) to about 150 mM). We speculate that the switch between these two secretory mechanisms is controlled by a series of luminal signals (e.g. pH, HCO(3)(-) concentration) acting on the apical membrane transporters in the duct cell.
Collapse
Affiliation(s)
- Y Sohma
- Department of Physiology, Osaka Medical College, Takatsuki, Osaka, Japan
| | | | | | | |
Collapse
|
32
|
Gray MA, O'Reilly C, Winpenny J, Argent B. Functional interactions of HCO3- with cystic fibrosis transmembrane conductance regulator. JOP 2001; 2:207-11. [PMID: 11875261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Disruption of normal cystic fibrosis transmembrane conductance regulator- (CFTR)-mediated Cl(-) transport is associated with cystic fibrosis (CF). CFTR is also required for HCO(3)(-) transport in many tissues such as the lungs, gastro-intestinal tract, and pancreas, although the exact role CFTR plays is uncertain. Given the importance of CFTR in HCO(3)(-) transport by so many CF-affected organ systems, it is perhaps surprising that relatively little is known about the interactions of HCO(3)(-) ions with CFTR. We have used patch clamp recordings from native pancreatic duct cells to study HCO(3)(-) permeation and interaction with CFTR. Ion selectivity studies shows that CFTR is between 3-5 times more selective for Cl(-) over HCO(3)(-). In addition, extracellular HCO(3)(-) has a novel inhibitory effect on cAMP-stimulated CFTR currents carried by Cl(-). The block by HCO(3)(-) was rapid, relatively independent of voltage and occurred over the physiological range of HCO(3)(-) concentrations. These data show that luminal HCO(3)(-) acts as a potent regulator of CFTR, and suggests that inhibition involves an external anion-binding site on the channel. This work has implications not only for elucidating mechanisms of HCO(3)(-) transport in epithelia, but also for approaches used to treat CF.
Collapse
Affiliation(s)
- M A Gray
- Department of Physiological Sciences, University Medical School, Newcastle upon Tyne, United Kingdom.
| | | | | | | |
Collapse
|
33
|
Huebner RC, Gray MA, Holt J, Wu XD, Mays JP. Characterization of a recombinant outer surface protein A (OspA) vaccine against Lyme disease. Dev Biol (Basel) 2001; 103:163-73. [PMID: 11214234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Lyme disease, the most prevalent tick-borne disease in the United States, results from infection with Borrelia burgdorferi sensu stricto. Early studies of Borrelia burgdorferi sensu stricto identified outer surface protein A (OspA), a lipoprotein on the surface of spirochetes that could be the target of protective antibodies to this agent. Pasteur Mérieux Connaught has developed a Lyme vaccine, ImuLyme, using recombinant OspA protein (rOspA). Methods were developed to routinely assess the identity, quantity, structure, purity, biological activity, heterogeneity, stability, and potency of rOspA. In addition, several methods were performed on a series of lots to support the routine testing methods and further our understanding of the physicochemical characteristics of rOspA. These tests were electrospray mass spectrometry, circular dichroism, two-dimensional gel electrophoresis, amino acid analysis, peptide mapping with peptide sequencing, and the application of proteomic methodology to identify trace contaminant host cell proteins. The results of these methods indicate that the rOspA lots are composed of highly purified and properly processed and folded rOspA with trace amounts of E. coli host cell proteins.
Collapse
Affiliation(s)
- R C Huebner
- Pasteur Mérieux Connaught, Swiftwater, PA 18370-0187, USA
| | | | | | | | | |
Collapse
|
34
|
Stewart GS, Glanville M, Aziz O, Simmons NL, Gray MA. Regulation of an outwardly rectifying chloride conductance in renal epithelial cells by external and internal calcium. J Membr Biol 2001; 180:49-64. [PMID: 11284203 DOI: 10.1007/s002320010058] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have used perforated patch clamp and Fura-2 microfluorescence measurements to study Ca(2+)-activated Cl- currents in cultured mouse renal inner medullary collecting duct cells (mIMCD-3). The conductance was spontaneously active under resting conditions and whole cell currents were time and voltage-independent with an outwardly rectifying current-voltage relationship. The channel blockers DIDS, niflumic acid, glybenclamide and NPPB reversibly decreased the basal currents, whereas the sulfhydryl agent, DTT produced an irreversible inhibition. Increasing or decreasing extracellular calcium produced parallel changes in the size of the basal currents. Variations in external Ca2+ were associated with corresponding changes in free cytosolic Ca2+ concentration. Increasing cytosolic Ca2+ by extracellular ATP or ionomycin, further enhanced Cl- conductance, with whole cell currents displaying identical biophysical properties to the basal currents. However, the agonist-stimulated currents were now increased by DTT exposure, but still inhibited by the other channel blockers. Using RT-PCR, three distinct mRNA transcripts belonging to the CLCA family of Ca(2+)-activated Cl- channel proteins were identified, two of which represent novel sequences. Whether different channels underlie the basal and agonist-stimulated currents in mIMCD-3 cells is unclear. Our findings establish a novel link between alterations in external and internal Ca2+ and the activity of Ca(2+)-activated Cl- transport in these cells.
Collapse
Affiliation(s)
- G S Stewart
- Department of Physiological Sciences, University Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | | | | | | | | |
Collapse
|
35
|
Abstract
Parker and Carlisle (Journal of Advanced Nursing 24, 771-778) argue that there is a scarcity of empirical research focusing on issues such as supernumerary status and mentorship in Project 2000 courses from the students' perspective. This paper presents the findings of a longitudinal cohort study using Grounded Theory to discover the effect(s) of mentorship on student nurses following the introduction of the 1992 programme of education leading to a Diploma of Higher Education in Nursing and registration with the United Kingdom Central Council (UKCC). The cohort consisted of 10 students from a large Scottish College of Nursing & Midwifery who were interviewed on five occasions during the three years of their course. Students also kept a diary to record their thoughts and experiences regarding mentorship during their practice placements. In addition, a further seven students volunteered to participate by diary only. Data were analysed with the aid of NUD.IST and subjected to the constant comparative method of analysis. Findings indicate that Diploma students quickly lose their idealistic view of their mentor and over time develop an insight into the qualities they perceive are required of an effective mentor. Students quickly become aware of the importance of choosing good role models and learning their own mentor's likes and dislikes as they realize this impinges on the outcome of their assessment. As students move into their Branch programme, a gradual distancing from their mentor is evident. This coincides with a development in their confidence, skills and a holistic perspective of care.
Collapse
Affiliation(s)
- M A Gray
- Head of Department, Faculty of Health and Life Sciences, Napier University, Edinburgh, Scotland.
| | | |
Collapse
|
36
|
Kose H, Boese SH, Glanville M, Gray MA, Brown CDA, Simmons NL. Bradykinin regulation of salt transport across mouse inner medullary collecting duct epithelium involves activation of a Ca(2+)-dependent Cl(-) conductance. Br J Pharmacol 2000; 131:1689-99. [PMID: 11139448 PMCID: PMC1572507 DOI: 10.1038/sj.bjp.0703749] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The mechanism by which bradykinin regulates renal epithelial salt transport has been investigated using a mouse inner medullary renal collecting duct cell-line mIMCD-K2. Using fura-2 loaded mIMCD-K2 cells bradykinin (100 nM) has been shown to induce a transient increase in intracellular Ca(2+) via activation of bradykinin B2 receptors localized to both the apical and basolateral epithelial cell surfaces. In mIMCD-K2 epithelial cell-layers clamped in Ussing chambers, 100 nM bradykinin via apical and basolateral bradykinin B2 receptors stimulated a transient increase in inward short-circuit current (I:(sc)) of similar duration to the increase in intracellular Ca(2+). Replacements of the bathing solution Na(+) by the impermeant cation, N-methyl-D-glucamine and of Cl(-) and HCO(3)(-) by the impermeant anion gluconate at either the apical (no reduction) or basal bathing solutions (abolition of the response) are consistent with the bradykinin-stimulated increase in inward I:(sc) resulting from basal to apical Cl(-) (anion) secretion. Using the slow whole cell configuration of the patch-clamp technique, bradykinin was shown to activate a transient Cl(-) selective whole cell current which showed time-dependent activation at positive membrane potentials and time-dependent inactivation at negative membrane potentials. These currents were distinct from those activated by forskolin (CFTR), but identical to those activated by exogenous ATP and are therefore consistent with bradykinin activation of a Ca(2+)-dependent Cl(-) conductance. The molecular identity of the Ca(2+)-dependent Cl(-) conductance has been investigated by an RT - PCR approach. Expression of an mRNA transcript with 96% identity to mCLCA1/2 was confirmed, however an additional but distinct mRNA transcript with only 81% of the identity to mCLCA1/2 was identified.
Collapse
Affiliation(s)
- H Kose
- Department of Physiological Sciences, Medical School, Framlington Place, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH
| | - S H Boese
- Department of Physiological Sciences, Medical School, Framlington Place, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH
| | - M Glanville
- Department of Physiological Sciences, Medical School, Framlington Place, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH
| | - M A Gray
- Department of Physiological Sciences, Medical School, Framlington Place, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH
| | - C D A Brown
- Department of Physiological Sciences, Medical School, Framlington Place, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH
| | - N L Simmons
- Department of Physiological Sciences, Medical School, Framlington Place, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH
- Author for correspondence:
| |
Collapse
|
37
|
Boese SH, Glanville M, Gray MA, Simmons NL. The swelling-activated anion conductance in the mouse renal inner medullary collecting duct cell line mIMCD-K2. J Membr Biol 2000; 177:51-64. [PMID: 10960153 DOI: 10.1007/s002320001099] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Swelling-activated Cl(-) currents (I(Cl,swell)) have been characterized in a mouse renal inner medullary collecting duct cell line (mIMCD-K2). Currents activated by exposing the cells to hypotonicity exhibited characteristic outward rectification and time- and voltage-dependent inactivation at positive potentials and showed an anion selectivity of I(-) > Br(-) > Cl(-) > Asp(-). NPPB (100 microm) inhibited the current in a voltage independent manner, as did exposure to 10 microm tamoxifen and 500 microm niflumic acid (NFA). In contrast, DIDS (100 microm) blocked the current with a characteristic voltage dependency. These characteristics of I(Cl, swell) in mIMCD-K2 cells are essentially identical to those of heterologously expressed cardiac CLC-3. A defining feature of CLC-3 is that activation of PKC by PDBu inhibits the conductance. In mIMCD-K2 cells preincubation with PDBu (100 nm) prevented the activation of I(Cl,swell) by hypotonicity. However, PDBu inhibition of I(Cl,swell) was reversed after PDBu withdrawal, but this was refractory to subsequent PDBu inhibition. Activation of either the cystic fibrosis transmembrane conductance regulator (CFTR) or Ca(2+) activated Cl(-) conductance (CaCC), which are coexpressed in mIMCD-K2 cells prior to PDBu treatment, abolished the PDBu inhibition of I(Cl,swell). Control of I(Cl,swell) by PKC therefore depends on the physiological status of the cell. In intact mIMCD-K2 layers in Ussing chambers, forskolin stimulation of an inward short-circuit current (due to transepithelial Cl(-) secretion via apical CFTR) was inhibited by cell swelling upon hypotonic exposure at the basolateral surface. Activation of I(Cl,swell) is therefore capable of regulating transepithelial Cl(-) secretion and suggests that I(Cl,swell) is located at the basolateral membrane. PDBu exposure prior to or during hypotonic challenge was ineffective in reversing the swelling-activated inhibition of Cl(-) secretion, but tamoxifen (100 microm) abolished the hypotonic inhibition of forskolin-stimulated short-circuit current (I(sc)). RT-PCR analysis confirmed expression of mRNA for members of the CLC family, including both CLC-2 and 3, in the mIMCD-K2 cell line.
Collapse
Affiliation(s)
- S H Boese
- Department of Physiological Sciences, Medical School, Framlington Place, University of Newcastle upon Tyne, Newcastle upon Tyne, NE2 4HH, UK
| | | | | | | |
Collapse
|
38
|
Abstract
We have used computer modeling to investigate how pancreatic duct cells can secrete a fluid containing near isotonic (approximately 140 mM) NaHCO3. Experimental data suggest that NaHCO3 secretion occurs in three steps: (i) accumulation of HCO3- across the basolateral membrane of the duct cell by Na(HCO3)n cotransporters, Na+/H+ exchangers and proton pumps; (ii) secretion of HCO3- across the luminal membrane on Cl-/HCO3- antiporters operating in parallel with Cl- channels; and (iii) diffusion of Na+ through the paracellular pathway. Programming the currently available experimental data into our computer model shows that this mechanism for HCO3- secretion is deficient in one important respect. While it can produce a relatively large volume of a HCO3(-)-rich fluid, it can only raise the luminal HCO3- concentration up to about 70 mM. To achieve secretion of 140 mM NaHCO3 by the model it is necessary to: (i) reduce the conductive Cl- permeability and increase the conductive HCO3- permeability of the luminal membrane of the duct cell, and (ii) reduce the activity of the luminal Cl-/HCO3- antiporters. Under these conditions most of the HCO3- is secreted via a conductive pathway. Based on our data, we propose that HCO3- secretion occurs mainly by the antiporter in duct segments near the acini (luminal HCO3- concentration up to approximately 70 mM), but mainly via channels further down the ductal tree (raising luminal HCO3- to approximately 140 mM).
Collapse
Affiliation(s)
- Y Sohma
- Department of Physiology, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | | | | | | |
Collapse
|
39
|
O'Reilly CM, Winpenny JP, Argent BE, Gray MA. Cystic fibrosis transmembrane conductance regulator currents in guinea pig pancreatic duct cells: inhibition by bicarbonate ions. Gastroenterology 2000; 118:1187-96. [PMID: 10833494 DOI: 10.1016/s0016-5085(00)70372-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND & AIMS Cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channels play an important role in HCO(3)(-) secretion by pancreatic duct cells (PDCs). Our aims were to characterize the CFTR conductance of guinea pig PDCs and to establish whether CFTR is regulated by HCO(3)(-). METHODS PDCs were isolated from small intralobular and interlobular ducts, and their Cl(- )conductance was studied using the whole-cell patch clamp technique. RESULTS Activation of a typical CFTR conductance by adenosine 3',5'-cyclic monophosphate (cAMP) was observed in 114 of 204 cells (56%). A larger (10-fold), time- and voltage-dependent Cl(-) conductance was activated in 39 of 204 cells (19%). Secretin had a similar effect. Coexpression of both conductances in the same cell was observed, and both conductances had similar anion selectivity and pharmacology. Extracellular HCO(3)(-) caused a dose-dependent inhibition of both currents (K(i), approximately 7 mmol/L), which was independent of intracellular and extracellular pH, and the PCO(2) and CO(3)(2-) content of the bathing solutions. CONCLUSIONS Two kinetically distinct Cl(-) conductances are activated by cAMP in guinea pig PDCs. Because these conductances are coexpressed and exhibit similar characteristics (anion selectivity, pharmacology, and HCO(3)(-) inhibition), we conclude that CFTR underlies them both. The inhibition of CFTR by HCO(3)(-) has implications for the current model of pancreatic ductal HCO(3)(-) secretion.
Collapse
Affiliation(s)
- C M O'Reilly
- Department of Physiological Sciences, University Medical School, Newcastle upon Tyne, England
| | | | | | | |
Collapse
|
40
|
Abstract
1. The properties of a hyperpolarization-activated Cl- current (Ihyp-act) in murine ciliated respiratory cells have been studied using whole cell patch clamping. 2. The current-voltage relationship was inwardly rectifying which was due to voltage-dependent gating of the channel. 3. Inward current was markedly sensitive to the extracellular Cl- concentration, an effect that was not related to changes in transmembrane Cl- gradient. Decreasing extracellular Cl- concentration to 6 mM caused a 70 % reduction in inward current with the dose-response relationship exhibiting a Hill coefficient of approximately 2.0 and an IC50 of 29 mM. 4. External anion replacement gave a selectivity sequence of Br- >= I- > Cl- > gluconate = aspartate. The more permeant halides significantly increased current density while the less permeant anions decreased current density, indicating that an extracellular anion is important for channel activity. 5. The conductance was unaffected by exposure to anisotonic pipette solutions or to increases in intracellular cAMP; however, current density was reduced dose dependently by increases in intracellular calcium concentration from 0.1 to 0.5 microM. These results indicate that Ihyp-act is unlikely to be involved in either volume regulation or cAMP/Ca2+-stimulated fluid secretion. 6. Decreasing extracellular pH to 5.0 irreversibly inhibited Ihyp-act. However, the current was fully active over the pH range 5.4-9.0 making it unlikely that it is modulated by extracellular pH under physiological conditions. 7. We speculate that Ihyp-act may have a role in basal Cl- absorption, acting as a Cl- sensor to maintain optimal volume and composition of airway surface liquid.
Collapse
Affiliation(s)
- R Tarran
- Department of Physiological Sciences, University Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | | | | |
Collapse
|
41
|
Boese SH, Glanville M, Aziz O, Gray MA, Simmons NL. Ca2+ and cAMP-activated Cl- conductances mediate Cl- secretion in a mouse renal inner medullary collecting duct cell line. J Physiol 2000; 523 Pt 2:325-38. [PMID: 10699078 PMCID: PMC2269816 DOI: 10.1111/j.1469-7793.2000.t01-1-00325.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
1. The nature of Cl- conductance(s) participating in transepithelial anion secretion by renal inner medullary collecting duct (IMCD, mIMCD-K2 cell line) was investigated. 2. Extracellular ATP (100 microM) stimulated a transient increase in both whole-cell Cl- conductance and intracellular free Ca2+. In contrast, ionomycin (10-100 nM) caused a sustained increase in whole-cell Cl- conductance. Pre-loading cells with the Ca2+ buffer BAPTA abolished the ATP-dependent responses and delayed the onset of the increase observed with ionomycin. 3. The Ca2+-activated whole-cell Cl- current stimulated by ATP (peak) and ionomycin (maximal) displayed (i) a linear steady-state current-voltage relationship and (ii) time and voltage dependence with slow activation at +80 mV and slow inactivation at -80 mV. In BAPTA-loaded cells, ionomycin-elicited whole-cell currents exhibited pronounced outward rectification with time-dependent activation/inactivation. 4. Ca2+-activated and forskolin-activated Cl- conductances co-exist since ATP activation of whole-cell current occurred during a maximal stimulation by forskolin in single cell recordings. 5. In IMCD epithelial layers, ATP and ionomycin stimulated an inward short circuit current (Isc) dependent upon basal medium Na+ and Cl-/HCO3- but independent of the presence of apical bathing medium Na+ and Cl-/HCO3-. This was identical to forskolin stimulation and consistent with transepithelial anion secretion. 6. PCR amplification of reverse-transcribed mRNA using gene-specific primers demonstrated expression of both cystic fibrosis transmembrane conductance regulator (CFTR) mRNA and Ca2+-activated Cl- channel (mCLCA1) mRNA in mIMCD-K2 cells. 7. Ca2+ and forskolin-activated Cl- conductances participate in anion secretion by IMCD.
Collapse
Affiliation(s)
- S H Boese
- Department of Physiological Sciences, Medical School, Framlington Place, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, UK
| | | | | | | | | |
Collapse
|
42
|
Becq F, Mettey Y, Gray MA, Galietta LJ, Dormer RL, Merten M, Métayé T, Chappe V, Marvingt-Mounir C, Zegarra-Moran O, Tarran R, Bulteau L, Dérand R, Pereira MM, McPherson MA, Rogier C, Joffre M, Argent BE, Sarrouilhe D, Kammouni W, Figarella C, Verrier B, Gola M, Vierfond JM. Development of substituted Benzo[c]quinolizinium compounds as novel activators of the cystic fibrosis chloride channel. J Biol Chem 1999; 274:27415-25. [PMID: 10488073 DOI: 10.1074/jbc.274.39.27415] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chloride channels play an important role in the physiology and pathophysiology of epithelia, but their pharmacology is still poorly developed. We have chemically synthesized a series of substituted benzo[c]quinolizinium (MPB) compounds. Among them, 6-hydroxy-7-chlorobenzo[c]quinolizinium (MPB-27) and 6-hydroxy-10-chlorobenzo[c]quinolizinium (MPB-07), which we show to be potent and selective activators of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. We examined the effect of MPB compounds on the activity of CFTR channels in a variety of established epithelial and nonepithelial cell systems. Using the iodide efflux technique, we show that MPB compounds activate CFTR chloride channels in Chinese hamster ovary (CHO) cells stably expressing CFTR but not in CHO cells lacking CFTR. Single and whole cell patch clamp recordings from CHO cells confirm that CFTR is the only channel activated by the drugs. Ussing chamber experiments reveal that the apical addition of MPB to human nasal epithelial cells produces a large increase of the short circuit current. This current can be totally inhibited by glibenclamide. Whole cell experiments performed on native respiratory cells isolated from wild type and CF null mice also show that MPB compounds specifically activate CFTR channels. The activation of CFTR by MPB compounds was glibenclamide-sensitive and 4, 4'-diisothiocyanostilbene-2,2'-disulfonic acid-insensitive. In the human tracheal gland cell line MM39, MPB drugs activate CFTR channels and stimulate the secretion of the antibacterial secretory leukoproteinase inhibitor. In submandibular acinar cells, MPB compounds slightly stimulate CFTR-mediated submandibular mucin secretion without changing intracellular cAMP and ATP levels. Similarly, in CHO cells MPB compounds have no effect on the intracellular levels of cAMP and ATP or on the activity of various protein phosphatases (PP1, PP2A, PP2C, or alkaline phosphatase). Our results provide evidence that substituted benzo[c]quinolizinium compounds are a novel family of activators of CFTR and of CFTR-mediated protein secretion and therefore represent a new tool to study CFTR-mediated chloride and secretory functions in epithelial tissues.
Collapse
Affiliation(s)
- F Becq
- Laboratoire de neurobiologie UPR-9024 CNRS, 31 ch. J. Aiguier F-13402 Marseille cedex 20, France.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Winpenny JP, Harris A, Hollingsworth MA, Argent BE, Gray MA. Calcium-activated chloride conductance in a pancreatic adenocarcinoma cell line of ductal origin (HPAF) and in freshly isolated human pancreatic duct cells. Pflugers Arch 1998; 435:796-803. [PMID: 9518508 DOI: 10.1007/s004240050586] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Using the whole-cell patch-clamp technique, a calcium-activated chloride conductance (CACC) could be elicited in HPAF cells by addition of 1 microM ionomycin to the bath solution (66 +/- 22 pA/pF;Vm + 60 mV) or by addition of 1 microM calcium to the pipette solution (136 +/- 17 pA/pF; Vm + 60 mV). Both conductances had similar biophysical characteristics, including time-dependent inactivation at hyperpolarising potentials and a linear/slightly outwardly rectifying current/voltage (I/V) curve with a reversal potential (Erev) close to the calculated chloride equilibrium potential. The anion permeability sequence obtained from shifts in Erev was I > Br >/= Cl. 4,4'-Diisothiocyanatostilbene disulphonic acid (DIDS, 500 microM) caused a 13% inhibition of the current (Vm + 60 mV) while 100 microM glibenclamide, 30 nM TS-TM-calix[4]arene and 10 microM tamoxifen, all chloride channel blockers, had no marked effects (8%, -6% and -2% inhibition respectively). Niflumic acid (100 microM) caused a voltage-dependent inhibition of the current of 48% and 17% (Vm +/- 60 mV, respectively). In freshly isolated human pancreatic duct cells (PDCs) a CACC was elicited with 1 microM calcium in the pipette solution (260 +/- 62 pA/pF; Vm + 60 mV). The presence of this CACC in human PDCs could provide a possible therapeutic pathway for treatment of pancreatic insufficiency of the human pancreas in cystic fibrosis.
Collapse
Affiliation(s)
- J P Winpenny
- Department of Physiological Sciences, The Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | | | | | | | | |
Collapse
|
44
|
Tarran R, Gray MA, Evans MJ, Colledge WH, Ratcliff R, Argent BE. Basal chloride currents in murine airway epithelial cells: modulation by CFTR. Am J Physiol 1998; 274:C904-13. [PMID: 9575786 DOI: 10.1152/ajpcell.1998.274.4.c904] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We have isolated ciliated respiratory cells from the nasal epithelium of wild-type and cystic fibrosis (CF) null mice and used the patch-clamp technique to investigate their basal conductances. Current-clamp experiments on unstimulated cells indicated the presence of K+ and Cl- conductances and, under certain conditions, a small Na+ conductance. Voltage-clamp experiments revealed three distinct Cl- conductances. Itv-indep was time and voltage independent with a linear current-voltage (I-V) plot; Iv-act exhibited activation at potentials greater than +/- 50 mV, giving an S-shaped I-V plot; and Ihyp-act was activated by hyperpolarizing potentials and had an inwardly rectified I-V plot. The current density sequence was Ihyp-act = Iv-act >> Itv-indep. These conductances had Cl(-)-to-N-methyl-D-glucamine cation permeability ratios of between 2.8 and 10.3 and were unaffected by tamoxifen, flufenamate, glibenclamide, DIDS, and 5-nitro-2-(3-phenylpropylamino) benzoic acid but were inhibited by Zn2+ and Gd3+. Itv-indep and Iv-act were present in wild-type and CF cells at equal density and frequency. However, Ihyp-act was detected in only 3% of CF cells compared with 26% of wild-type cells, suggesting that this conductance may be modulated by cystic fibrosis transmembrane conductance regulator (CFTR).
Collapse
Affiliation(s)
- R Tarran
- Department of Physiological Sciences, University Medical School, Newcastle upon Tyne, United Kingdom
| | | | | | | | | | | |
Collapse
|
45
|
Abstract
We have recently shown that a maxi-K+ channel from vas deferens epithelial cells contains two Ba2+-binding sites accessible from the external side: a "flickering" site located deep in the channel pore and a "slow" site located close to the extracellular mouth of the channel. Using the patch-clamp technique, we have now studied the effect of internal Ba2+ on this channel. Cytoplasmic Ba2+ produced a voltage- and concentration-dependent "slow" type of block with a dissociation constant of approximately 100 microM. However, based on its voltage dependence and sensitivity to K+ concentration, this block was clearly different from the external "slow" Ba2+ block previously described. Kinetic analysis also revealed a novel "fast flickering" block restricted to channel bursts, with an unblocking rate of approximately 310 s(-1), some 10-fold faster than the external "flickering" block. Taken together, these results show that this channel contains multiple Ba2+-binding sites within the conduction pore. We have incorporated this information into a new model of Ba2+ block, a novel feature of which is that internal "slow" block results from the binding of at least two Ba2+ ions. Our results suggest that current models for Ba2+ block of maxi-K+ channels need to be revised.
Collapse
Affiliation(s)
- Y Sohma
- Department of Physiological Sciences, University Medical School, Newcastle upon Tyne, England
| | | | | | | |
Collapse
|
46
|
Gray MA. Pharmacologic management of obesity. Orthop Nurs 1997; 16:70-3. [PMID: 9416161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Obesity is a major health problem in the United States. It is not only a problem in itself, but it is a predisposing factor for many chronic illnesses. Pharmaceutical houses have devoted much research in the development of drugs to combat the problem. While diet and exercise continue to be the first line of defense, many diet drugs are available on the market to help an individual lose weight. This article discusses some of the theories that appear to explain the development of the overweight condition and provides basic information on the drugs currently in use.
Collapse
Affiliation(s)
- M A Gray
- County College of Morris, Randolph, New Jersey, USA
| |
Collapse
|
47
|
Abstract
Tuberculosis is an old disease, and for some time thought to be almost eliminated in industrial societies. With the advent of the AIDS epidemic, it has made a comeback and often in a form more virulent than was seen in the past. This article summarizes the drugs used to treat the disease and suggests ways nurses may help keep this once underestimated problem in control.
Collapse
Affiliation(s)
- M A Gray
- County College of Morris, Randolph, New Jersey, USA
| |
Collapse
|
48
|
Peregrine AS, Gray MA, Moloo SK. Cross-resistance associated with development of resistance to isometamidium in a clone of Trypanosoma congolense. Antimicrob Agents Chemother 1997; 41:1604-6. [PMID: 9210695 PMCID: PMC163969 DOI: 10.1128/aac.41.7.1604] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Resistance to isometamidium was increased 94-fold in a clone of Trypanosoma congolense (clone IL 1180) by repeated subcurative treatment of infected mice for 11 months. This was associated with 3.4-, 33-, and 4.2-fold increases in resistance to diminazene, homidium, and quinapyramine, respectively. Both T. congolense IL 1180 and the resistant derivative were able to undergo cyclical development in Glossina morsitans centralis tsetse flies, producing hypopharyngeal infection rates of 40.0 and 39.8%, respectively.
Collapse
Affiliation(s)
- A S Peregrine
- International Livestock Research Institute, Nairobi, Kenya.
| | | | | |
Collapse
|
49
|
Gray MA. Historical developments in the drug therapy of diabetes. Orthop Nurs 1997; 16:81-7. [PMID: 9155419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
It is suggested that some 16 million Americans have diabetes, although about only one-half of them are diagnosed. Type I or IDDM diabetics must take insulin in some form to maintain their life. A larger number of Americans have Type II or NIDDM, and many can be treated with a combination of diet and exercise. Many of the Type II diabetics will need to take oral medications at some point in their life and a somewhat smaller number may find that they must use insulin injections if they are to maintain good control of their diabetes. This article describes the historical events leading up to the present therapeutic options for both Type I and Type II diabetics. Also included is a list of drugs that are in the research phase at the present time as well as a list of internet sites where the practitioner and patient alike can keep up to date on new developments in the treatment of diabetes.
Collapse
Affiliation(s)
- M A Gray
- County College of Morris, Randolph, New Jersey, USA
| |
Collapse
|
50
|
Abstract
A mathematical model of the HCO-3-secreting pancreatic ductal epithelium was developed using network thermodynamics. With a minimal set of assumptions, the model accurately reproduced the experimentally measured membrane potentials, voltage divider ratio, transepithelial resistance and short-circuit current of nonstimulated ducts that were microperfused and bathed with a CO2/HCO-3-free, HEPES-buffered solution, and also the intracellular pH of duct cells bathed in a CO2/HCO-3-buffered solution. The model also accurately simulated: (i) the effect of step changes in basolateral K+ concentration, and the effect of K+ channel blockers on basolateral membrane potential; (ii) the intracellular acidification caused by a Na+-free extracellular solution and the effect of amiloride on this acidification; and (iii) the intracellular alkalinization caused by a Cl--free extracellular solution and the effect of DIDS on this alkalinization. In addition, the model predicted that the luminal Cl- conductance plays a key role in controlling both the HCO-3 secretory rate and intracellular pH during HCO-3 secretion. We believe that the model will be helpful in the analysis of experimental data and improve our understanding of HCO-3-transporting mechanisms in pancreatic duct cells.
Collapse
Affiliation(s)
- Y Sohma
- Department of Physiological Sciences, University Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | | | | | | |
Collapse
|