51
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Shamin M, Benedyk TH, Graham SC, Deane JE. The lipid transfer protein Saposin B does not directly bind CD1d for lipid antigen loading. Wellcome Open Res 2019; 4:117. [PMID: 31667358 PMCID: PMC6807164 DOI: 10.12688/wellcomeopenres.15368.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2019] [Indexed: 12/13/2022] Open
Abstract
Background: Lipid antigens are presented on the surface of cells by the CD1 family of glycoproteins, which have structural and functional similarity to MHC class I molecules. The hydrophobic lipid antigens are embedded in membranes and inaccessible to the lumenal lipid-binding domain of CD1 molecules. Therefore, CD1 molecules require lipid transfer proteins for lipid loading and editing. CD1d is loaded with lipids in late endocytic compartments, and lipid transfer proteins of the saposin family have been shown to play a crucial role in this process. However, the mechanism by which saposins facilitate lipid binding to CD1 molecules is not known and is thought to involve transient interactions between protein components to ensure CD1-lipid complexes can be efficiently trafficked to the plasma membrane for antigen presentation. Of the four saposin proteins, the importance of Saposin B (SapB) for loading of CD1d is the most well-characterised. However, a direct interaction between CD1d and SapB has yet to be described. Methods: In order to determine how SapB might load lipids onto CD1d, we used purified, recombinant CD1d and SapB and carried out a series of highly sensitive binding assays to monitor direct interactions. We performed equilibrium binding analysis, chemical cross-linking and co-crystallisation experiments, under a range of different conditions. Results: We could not demonstrate a direct interaction between SapB and CD1d using any of these binding assays. Conclusions: This work strongly indicates that the role of SapB in lipid loading does not involve direct binding to CD1d. We discuss the implication of this for our understanding of lipid loading of CD1d and propose several factors that may influence this process.
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Affiliation(s)
- Maria Shamin
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Tomasz H. Benedyk
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Stephen C. Graham
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Janet E. Deane
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0QQ, UK
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52
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Driving Neurogenesis in Neural Stem Cells with High Sensitivity Optogenetics. Neuromolecular Med 2019; 22:139-149. [PMID: 31595404 DOI: 10.1007/s12017-019-08573-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/21/2019] [Indexed: 01/15/2023]
Abstract
Optogenetic stimulation of neural stem cells (NSCs) enables their activity-dependent photo-modulation. This provides a spatio-temporal tool for studying activity-dependent neurogenesis and for regulating the differentiation of the transplanted NSCs. Currently, this is mainly driven by viral transfection of channelrhodopsin-2 (ChR2) gene, which requires high irradiance and complex in vivo/vitro stimulation systems. Additionally, despite the extensive application of optogenetics in neuroscience, the transcriptome-level changes induced by optogenetic stimulation of NSCs have not been elucidated yet. Here, we made transformed NSCs (SFO-NSCs) stably expressing one of the step-function opsin (SFO)-variants of chimeric channelrhodopsins, ChRFR(C167A), which is more sensitive to blue light than native ChR2, via a non-viral transfection system using piggyBac transposon. We set up a simple low-irradiance optical stimulation (OS)-incubation system that induced c-fos mRNA expression, which is activity-dependent, in differentiating SFO-NSCs. More neuron-like SFO-NCSs, which had more elongated axons, were differentiated with daily OS than control cells without OS. This was accompanied by positive/negative changes in the transcriptome involved in axonal remodeling, synaptic plasticity, and microenvironment modulation with the up-regulation of several genes involved in the Ca2+-related functions. Our approach could be applied for stem cell transplantation studies in tissue with two strengths: lower carcinogenicity and less irradiance needed for tissue penetration.
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Heybrock S, Kanerva K, Meng Y, Ing C, Liang A, Xiong ZJ, Weng X, Ah Kim Y, Collins R, Trimble W, Pomès R, Privé GG, Annaert W, Schwake M, Heeren J, Lüllmann-Rauch R, Grinstein S, Ikonen E, Saftig P, Neculai D. Lysosomal integral membrane protein-2 (LIMP-2/SCARB2) is involved in lysosomal cholesterol export. Nat Commun 2019; 10:3521. [PMID: 31387993 PMCID: PMC6684646 DOI: 10.1038/s41467-019-11425-0] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 07/12/2019] [Indexed: 11/30/2022] Open
Abstract
The intracellular transport of cholesterol is subject to tight regulation. The structure of the lysosomal integral membrane protein type 2 (LIMP-2, also known as SCARB2) reveals a large cavity that traverses the molecule and resembles the cavity in SR-B1 that mediates lipid transfer. The detection of cholesterol within the LIMP-2 structure and the formation of cholesterol-like inclusions in LIMP-2 knockout mice suggested the possibility that LIMP2 transports cholesterol in lysosomes. We present results of molecular modeling, crosslinking studies, microscale thermophoresis and cell-based assays that support a role of LIMP-2 in cholesterol transport. We show that the cavity in the luminal domain of LIMP-2 can bind and deliver exogenous cholesterol to the lysosomal membrane and later to lipid droplets. Depletion of LIMP-2 alters SREBP-2-mediated cholesterol regulation, as well as LDL-receptor levels. Our data indicate that LIMP-2 operates in parallel with Niemann Pick (NPC)-proteins, mediating a slower mode of lysosomal cholesterol export.
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Affiliation(s)
- Saskia Heybrock
- Biochemisches Institut, Christian-Albrechts-Universität Kiel, Kiel, Germany
| | - Kristiina Kanerva
- Faculty of Medicine, Anatomy and Stem Cells and Metabolism Research Program, University of Helsinki, Helsinki, Finland
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Ying Meng
- Department of Cell Biology, and Department of Pathology Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Chris Ing
- Program in Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, M5S 1A8, Canada
| | - Anna Liang
- Program in Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, M5S 1A8, Canada
| | - Zi-Jian Xiong
- Department of Biochemistry, University of Toronto, Toronto, M5S 1A8, Canada
| | - Xialian Weng
- Department of Cell Biology, and Department of Pathology Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Young Ah Kim
- Department of Chemistry and Biochemistry, Queens College, City University of New York, Flushing, New York, USA
| | - Richard Collins
- Cell Biology Program, Hospital for Sick Children, Toronto, M5G 1X8, Canada
| | - William Trimble
- Department of Biochemistry, University of Toronto, Toronto, M5S 1A8, Canada
- Cell Biology Program, Hospital for Sick Children, Toronto, M5G 1X8, Canada
- Department of Physiology, University of Toronto, Toronto, M5S 1A8, Canada
| | - Régis Pomès
- Program in Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, M5S 1A8, Canada
| | - Gilbert G Privé
- Department of Biochemistry, University of Toronto, Toronto, M5S 1A8, Canada
- Princes Margaret Cancer Centre, Toronto, ON, Canada
| | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, Leuven, Belgium
| | - Michael Schwake
- Faculty of Chemistry, Biochemistry III, University of Bielefeld, 33615, Bielefeld, Germany
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Joerg Heeren
- Institut für Biochemie und Molekulare Zellbiologie, Zentrum für Experimentelle Medizin, Universitätsklinikum Hamburg-Eppendorf, Hamburg-Eppendorf, Germany
| | | | - Sergio Grinstein
- Department of Biochemistry, University of Toronto, Toronto, M5S 1A8, Canada.
- Cell Biology Program, Hospital for Sick Children, Toronto, M5G 1X8, Canada.
| | - Elina Ikonen
- Faculty of Medicine, Anatomy and Stem Cells and Metabolism Research Program, University of Helsinki, Helsinki, Finland.
- Minerva Foundation Institute for Medical Research, Helsinki, Finland.
| | - Paul Saftig
- Biochemisches Institut, Christian-Albrechts-Universität Kiel, Kiel, Germany.
| | - Dante Neculai
- Department of Cell Biology, and Department of Pathology Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China.
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54
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Shamin M, Benedyk TH, Graham SC, Deane JE. The lipid transfer protein Saposin B does not directly bind CD1d for lipid antigen loading. Wellcome Open Res 2019; 4:117. [PMID: 31667358 PMCID: PMC6807164 DOI: 10.12688/wellcomeopenres.15368.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2019] [Indexed: 10/15/2023] Open
Abstract
Background: Lipid antigens are presented on the surface of cells by the CD1 family of glycoproteins, which have structural and functional similarity to MHC class I molecules. The hydrophobic lipid antigens are embedded in membranes and inaccessible to the lumenal lipid-binding domain of CD1 molecules. Therefore, CD1 molecules require lipid transfer proteins for lipid loading and editing. CD1d is loaded with lipids in late endocytic compartments, and lipid transfer proteins of the saposin family have been shown to play a crucial role in this process. However, the mechanism by which saposins facilitate lipid binding to CD1 molecules is not known and is thought to involve transient interactions between protein components to ensure CD1-lipid complexes can be efficiently trafficked to the plasma membrane for antigen presentation. Of the four saposin proteins, the importance of Saposin B (SapB) for loading of CD1d is the most well-characterised. However, a direct interaction between CD1d and SapB has yet to be described. Methods: In order to determine how SapB might load lipids onto CD1d, we used purified, recombinant CD1d and SapB and carried out a series of highly sensitive binding assays to monitor direct interactions. We performed equilibrium binding analysis, chemical cross-linking and co-crystallisation experiments, under a range of different conditions. Results: We could not demonstrate a direct interaction between SapB and CD1d using any of these binding assays. Conclusions: This work establishes comprehensively that the role of SapB in lipid loading does not involve direct binding to CD1d. We discuss the implication of this for our understanding of lipid loading of CD1d and propose several factors that may influence this process.
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Affiliation(s)
- Maria Shamin
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Tomasz H. Benedyk
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Stephen C. Graham
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Janet E. Deane
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0QQ, UK
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55
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Schertzer MD, Thulson E, Braceros KCA, Lee DM, Hinkle ER, Murphy RM, Kim SO, Vitucci ECM, Calabrese JM. A piggyBac-based toolkit for inducible genome editing in mammalian cells. RNA (NEW YORK, N.Y.) 2019; 25:1047-1058. [PMID: 31101683 PMCID: PMC6633203 DOI: 10.1261/rna.068932.118] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 05/15/2019] [Indexed: 05/30/2023]
Abstract
We describe the development and application of a novel series of vectors that facilitate CRISPR-Cas9-mediated genome editing in mammalian cells, which we call CRISPR-Bac. CRISPR-Bac leverages the piggyBac transposon to randomly insert CRISPR-Cas9 components into mammalian genomes. In CRISPR-Bac, a single piggyBac cargo vector containing a doxycycline-inducible Cas9 or catalytically dead Cas9 (dCas9) variant and a gene conferring resistance to Hygromycin B is cotransfected with a plasmid expressing the piggyBac transposase. A second cargo vector, expressing a single-guide RNA (sgRNA) of interest, the reverse-tetracycline TransActivator (rtTA), and a gene conferring resistance to G418, is also cotransfected. Subsequent selection on Hygromycin B and G418 generates polyclonal cell populations that stably express Cas9, rtTA, and the sgRNA(s) of interest. We show that CRISPR-Bac can be used to knock down proteins of interest, to create targeted genetic deletions with high efficiency, and to activate or repress transcription of protein-coding genes and an imprinted long noncoding RNA. The ratio of sgRNA-to-Cas9-to-transposase can be adjusted in transfections to alter the average number of cargo insertions into the genome. sgRNAs targeting multiple genes can be inserted in a single transfection. CRISPR-Bac is a versatile platform for genome editing that simplifies the generation of mammalian cells that stably express the CRISPR-Cas9 machinery.
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Affiliation(s)
- Megan D Schertzer
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Eliza Thulson
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Keean C A Braceros
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Curriculum in Mechanistic, Interdisciplinary Studies of Biological Systems, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - David M Lee
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Emma R Hinkle
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Ryan M Murphy
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Curriculum in Mechanistic, Interdisciplinary Studies of Biological Systems, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Susan O Kim
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Eva C M Vitucci
- Curriculum in Toxicology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- U.S. Environmental Protection Agency, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - J Mauro Calabrese
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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56
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Assessment of fed-batch cultivation strategies for an inducible CHO cell line. J Biotechnol 2019; 298:45-56. [DOI: 10.1016/j.jbiotec.2019.04.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 04/04/2019] [Accepted: 04/04/2019] [Indexed: 12/28/2022]
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57
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Ong EC, Smidt P, McGrew JT. Limiting the metabolic burden of recombinant protein expression during selection yields pools with higher expression levels. Biotechnol Prog 2019; 35:e2839. [PMID: 31090257 DOI: 10.1002/btpr.2839] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 05/02/2019] [Accepted: 05/13/2019] [Indexed: 12/13/2022]
Abstract
In order to avoid the metabolic burden of protein expression during cell growth, and to avoid potential toxicity of recombinant proteins, microbial expression systems typically utilize regulated expression vectors. In contrast, constitutive expression vectors have usually been utilized for isolation of protein expressing mammalian cell lines. In mammalian systems, inducible expression vectors are typically utilized for only those proteins that are toxic when overexpressed. We developed a tetracycline regulated expression system in CHO cells, and show that cell pools selected in the uninduced state recover faster than those selected in the induced state even though the proteins showed no apparent toxicity or expression instability. Furthermore, cell pools selected in the uninduced state had higher expression levels when protein expression was turned on only in production cultures compared to pools that were selected and maintained in the induced state through production. We show a titer improvement of greater than twofold for an Fc-fusion protein and greater than 50% improvement for a recombinant antibody. The improvement is primarily due to an increase in specific productivity. Recombinant protein mRNA levels correlate strongly with protein expression levels and are highest in those cultures selected in the uninduced state and only induced during production. These data are consistent with a model where CHO cell lines with constitutive expression select for subclones with lower expression levels.
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Affiliation(s)
- E-Ching Ong
- Process Design, Just Biotherapeutics, Seattle, Washington
| | - Pauline Smidt
- Process Design, Just Biotherapeutics, Seattle, Washington
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58
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Zhang H, Bagherie-Lachidan M, Badouel C, Enderle L, Peidis P, Bremner R, Kuure S, Jain S, McNeill H. FAT4 Fine-Tunes Kidney Development by Regulating RET Signaling. Dev Cell 2019; 48:780-792.e4. [PMID: 30853441 DOI: 10.1016/j.devcel.2019.02.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 12/06/2018] [Accepted: 02/01/2019] [Indexed: 12/27/2022]
Abstract
FAT4 mutations lead to several human diseases that disrupt the normal development of the kidney. However, the underlying mechanism remains elusive. In studying the duplex kidney phenotypes observed upon deletion of Fat4 in mice, we have uncovered an interaction between the atypical cadherin FAT4 and RET, a tyrosine kinase receptor essential for kidney development. Analysis of kidney development in Fat4-/- kidneys revealed abnormal ureteric budding and excessive RET signaling. Removal of one copy of the RET ligand Gdnf rescues Fat4-/- kidney development, supporting the proposal that loss of Fat4 hyperactivates RET signaling. Conditional knockout analyses revealed a non-autonomous role for Fat4 in regulating RET signaling. Mechanistically, we found that FAT4 interacts with RET through extracellular cadherin repeats. Importantly, expression of FAT4 perturbs the assembly of the RET-GFRA1-GDNF complex, reducing RET signaling. Thus, FAT4 interacts with RET to fine-tune RET signaling, establishing a juxtacrine mechanism controlling kidney development.
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Affiliation(s)
- Hongtao Zhang
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Mazdak Bagherie-Lachidan
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Caroline Badouel
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 Route de Narbonne, Toulouse 31062, France
| | - Leonie Enderle
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Philippos Peidis
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Rod Bremner
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Departments of Ophthalmology and Visual Science, and Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Satu Kuure
- GM-unit at Laboratory Animal Centre, HiLIFE and Medicum, University of Helsinki, Helsinki 00014, Finland
| | - Sanjay Jain
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Helen McNeill
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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59
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Wei Y, Xiong ZJ, Li J, Zou C, Cairo CW, Klassen JS, Privé GG. Crystal structures of human lysosomal EPDR1 reveal homology with the superfamily of bacterial lipoprotein transporters. Commun Biol 2019; 2:52. [PMID: 30729188 PMCID: PMC6363788 DOI: 10.1038/s42003-018-0262-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 12/11/2018] [Indexed: 01/01/2023] Open
Abstract
EPDR1, a member of the ependymin-related protein family, is a relatively uncharacterized protein found in the lysosomes and secretomes of most vertebrates. Despite having roles in human disease and health, the molecular functions of EPDR1 remain unknown. Here, we present crystal structures of human EPDR1 and reveal that the protein adopts a fold previously seen only in bacterial proteins related to the LolA lipoprotein transporter. EPDR1 forms a homodimer with an overall shape resembling a half-shell with two non-overlapping hydrophobic grooves on the flat side of the hemisphere. EPDR1 can interact with membranes that contain negatively charged lipids, including BMP and GM1, and we suggest that EPDR1 may function as a lysosomal activator protein or a lipid transporter. A phylogenetic analysis reveals that the fold is more widely distributed than previously suspected, with representatives identified in all branches of cellular life.
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Affiliation(s)
- Yong Wei
- Princess Margaret Cancer Centre, Toronto, M5G 1L7 ON Canada
| | - Zi Jian Xiong
- Department of Biochemistry, University of Toronto, Toronto, M5S 1A8 ON Canada
| | - Jun Li
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, T6G 2G2 AB Canada
| | - Chunxia Zou
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, T6G 2G2 AB Canada
| | - Christopher W. Cairo
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, T6G 2G2 AB Canada
| | - John S. Klassen
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, T6G 2G2 AB Canada
| | - Gilbert G. Privé
- Princess Margaret Cancer Centre, Toronto, M5G 1L7 ON Canada
- Department of Biochemistry, University of Toronto, Toronto, M5S 1A8 ON Canada
- Department of Medical Biophysics, University of Toronto, Toronto, M5G 1L7 ON Canada
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60
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Enhancers Improve the AID-Induced Hypermutation in Episomal Vector for Antibody Affinity Maturation in Mammalian Cell Display. Antibodies (Basel) 2018; 7:antib7040042. [PMID: 31544892 PMCID: PMC6698961 DOI: 10.3390/antib7040042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 12/10/2018] [Accepted: 12/11/2018] [Indexed: 12/03/2022] Open
Abstract
The induction of somatic hypermutation (SHM) in various cell lines by activation-induced cytidine deaminase (AID) has been used in protein-directed selection, especially in antibody affinity maturation. Several antibody affinity maturation systems based on mammalian cells have been developed in recent years, i.e., 293T, H1299, Raji and CHO cells. However, the efficiency of in vitro AID-induced hypermutation is low, restricting the application of such systems. In this study, we examined the role of Ig and Ek enhancers in enhancing SHM in the episomal vector pCEP4 that expresses an anti-high mobility group box 1 (HMGB1) full-length antibody. The plasmid containing the two enhancers exhibited two-fold improvement of mutation rate over pCEP4 in an AID expression H1299 cell line (H1299-AID). With the engineered episomal vector, we improved the affinity of this antibody in H1299-AID cells by 20-fold.
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61
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Sun H, Yang W, Tian Y, Zeng X, Zhou J, Mok MTS, Tang W, Feng Y, Xu L, Chan AWH, Tong JH, Cheung YS, Lai PBS, Wang HKS, Tsang SW, Chow KL, Hu M, Liu R, Huang L, Yang B, Yang P, To KF, Sung JJY, Wong GLH, Wong VWS, Cheng ASL. An inflammatory-CCRK circuitry drives mTORC1-dependent metabolic and immunosuppressive reprogramming in obesity-associated hepatocellular carcinoma. Nat Commun 2018; 9:5214. [PMID: 30523261 PMCID: PMC6283830 DOI: 10.1038/s41467-018-07402-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 10/31/2018] [Indexed: 02/07/2023] Open
Abstract
Obesity increases the risk of hepatocellular carcinoma (HCC) especially in men, but the molecular mechanism remains obscure. Here, we show that an androgen receptor (AR)-driven oncogene, cell cycle-related kinase (CCRK), collaborates with obesity-induced pro-inflammatory signaling to promote non-alcoholic steatohepatitis (NASH)-related hepatocarcinogenesis. Lentivirus-mediated Ccrk ablation in liver of male mice fed with high-fat high-carbohydrate diet abrogates not only obesity-associated lipid accumulation, glucose intolerance and insulin resistance, but also HCC development. Mechanistically, CCRK fuels a feedforward loop by inducing STAT3-AR promoter co-occupancy and transcriptional up-regulation, which in turn activates mTORC1/4E-BP1/S6K/SREBP1 cascades via GSK3β phosphorylation. Moreover, hepatic CCRK induction in transgenic mice stimulates mTORC1-dependent G-csf expression to enhance polymorphonuclear myeloid-derived suppressor cell recruitment and tumorigenicity. Finally, the STAT3-AR-CCRK-mTORC1 pathway components are concordantly over-expressed in human NASH-associated HCCs. These findings unveil the dual roles of an inflammatory-CCRK circuitry in driving metabolic and immunosuppressive reprogramming through mTORC1 activation, thereby establishing a pro-tumorigenic microenvironment for HCC development.
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Affiliation(s)
- Hanyong Sun
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China
- Department of Liver Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Weiqin Yang
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Yuan Tian
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xuezhen Zeng
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Jingying Zhou
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Myth T S Mok
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Wenshu Tang
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Yu Feng
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Liangliang Xu
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Anthony W H Chan
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong, China
| | - Joanna H Tong
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong, China
| | - Yue-Sun Cheung
- Department of Surgery, The Chinese University of Hong Kong, Hong Kong, China
| | - Paul B S Lai
- Department of Surgery, The Chinese University of Hong Kong, Hong Kong, China
| | - Hector K S Wang
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Shun-Wa Tsang
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - King-Lau Chow
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Mengying Hu
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Rihe Liu
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy and Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Leaf Huang
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Bing Yang
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Pengyuan Yang
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Ka-Fai To
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong, China
- State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong, China
| | - Joseph J Y Sung
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China
- State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China
| | - Grace L H Wong
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
- State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China.
| | - Vincent W S Wong
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
- State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China.
| | - Alfred S L Cheng
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China.
- State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, China.
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62
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Elegheert J, Behiels E, Bishop B, Scott S, Woolley RE, Griffiths SC, Byrne EFX, Chang VT, Stuart DI, Jones EY, Siebold C, Aricescu AR. Lentiviral transduction of mammalian cells for fast, scalable and high-level production of soluble and membrane proteins. Nat Protoc 2018; 13:2991-3017. [PMID: 30455477 PMCID: PMC6364805 DOI: 10.1038/s41596-018-0075-9] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Structural, biochemical and biophysical studies of eukaryotic soluble and membrane proteins require their production in milligram quantities. Although large-scale protein expression strategies based on transient or stable transfection of mammalian cells are well established, they are associated with high consumable costs, limited transfection efficiency or long and tedious selection of clonal cell lines. Lentiviral transduction is an efficient method for the delivery of transgenes to mammalian cells and unifies the ease of use and speed of transient transfection with the robust expression of stable cell lines. In this protocol, we describe the design and step-by-step application of a lentiviral plasmid suite, termed pHR-CMV-TetO2, for the constitutive or inducible large-scale production of soluble and membrane proteins in HEK293 cell lines. Optional features include bicistronic co-expression of fluorescent marker proteins for enrichment of co-transduced cells using cell sorting and of biotin ligase for in vivo biotinylation. We demonstrate the efficacy of the method for a set of soluble proteins and for the G-protein-coupled receptor (GPCR) Smoothened (SMO). We further compare this method with baculovirus transduction of mammalian cells (BacMam), using the type-A γ-aminobutyric acid receptor (GABAAR) β3 homopentamer as a test case. The protocols described here are optimized for simplicity, speed and affordability; lead to a stable polyclonal cell line and milligram-scale amounts of protein in 3-4 weeks; and routinely achieve an approximately three- to tenfold improvement in protein production yield per cell as compared to transient transduction or transfection.
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Affiliation(s)
- Jonathan Elegheert
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, Bordeaux, France.
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France.
| | - Ester Behiels
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, Bordeaux, France
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - Benjamin Bishop
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Suzanne Scott
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Rachel E Woolley
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Samuel C Griffiths
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Eamon F X Byrne
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Veronica T Chang
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - David I Stuart
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
| | - A Radu Aricescu
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK.
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63
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Ilca FT, Neerincx A, Hermann C, Marcu A, Stevanović S, Deane JE, Boyle LH. TAPBPR mediates peptide dissociation from MHC class I using a leucine lever. eLife 2018; 7:40126. [PMID: 30484775 PMCID: PMC6307860 DOI: 10.7554/elife.40126] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Accepted: 11/28/2018] [Indexed: 11/29/2022] Open
Abstract
Tapasin and TAPBPR are known to perform peptide editing on major histocompatibility complex class I (MHC I) molecules; however, the precise molecular mechanism(s) involved in this process remain largely enigmatic. Here, using immunopeptidomics in combination with novel cell-based assays that assess TAPBPR-mediated peptide exchange, we reveal a critical role for the K22-D35 loop of TAPBPR in mediating peptide exchange on MHC I. We identify a specific leucine within this loop that enables TAPBPR to facilitate peptide dissociation from MHC I. Moreover, we delineate the molecular features of the MHC I F pocket required for TAPBPR to promote peptide dissociation in a loop-dependent manner. These data reveal that chaperone-mediated peptide editing on MHC I can occur by different mechanisms dependent on the C-terminal residue that the MHC I accommodates in its F pocket and provide novel insights that may inform the therapeutic potential of TAPBPR manipulation to increase tumour immunogenicity.
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Affiliation(s)
- F Tudor Ilca
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Andreas Neerincx
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Clemens Hermann
- Department of Integrative Biomedical Sciences, Division of Chemical and Systems Biology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Ana Marcu
- Department of Immunology, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, Germany
| | - Stefan Stevanović
- Department of Immunology, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, Germany.,DKFZ Partner Site Tübingen, German Cancer Consortium, Tübingen, Germany
| | - Janet E Deane
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Louise H Boyle
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
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64
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Axonal Transport Enables Neuron-to-Neuron Propagation of Human Coronavirus OC43. J Virol 2018; 92:JVI.00404-18. [PMID: 29925652 DOI: 10.1128/jvi.00404-18] [Citation(s) in RCA: 305] [Impact Index Per Article: 50.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/08/2018] [Indexed: 02/08/2023] Open
Abstract
Human coronaviruses (HCoVs) are recognized respiratory pathogens for which accumulating evidence indicates that in vulnerable patients the infection can cause more severe pathologies. HCoVs are not always confined to the upper respiratory tract and can invade the central nervous system (CNS) under still unclear circumstances. HCoV-induced neuropathologies in humans are difficult to diagnose early enough to allow therapeutic interventions. Making use of our already described animal model of HCoV neuropathogenesis, we describe the route of neuropropagation from the nasal cavity to the olfactory bulb and piriform cortex and then the brain stem. We identified neuron-to-neuron propagation as one underlying mode of virus spreading in cell culture. Our data demonstrate that both passive diffusion of released viral particles and axonal transport are valid propagation strategies used by the virus. We describe for the first time the presence along axons of viral platforms whose static dynamism is reminiscent of viral assembly sites. We further reveal that HCoV OC43 modes of propagation can be modulated by selected HCoV OC43 proteins and axonal transport. Our work, therefore, identifies processes that may govern the severity and nature of HCoV OC43 neuropathogenesis and will make possible the development of therapeutic strategies to prevent occurrences.IMPORTANCE Coronaviruses may invade the CNS, disseminate, and participate in the induction of neurological diseases. Their neuropathogenicity is being increasingly recognized in humans, and the presence and persistence of human coronaviruses (HCoV) in human brains have been proposed to cause long-term sequelae. Using our mouse model relying on natural susceptibility to HCoV OC43 and neuronal cell cultures, we have defined the most relevant path taken by HCoV OC43 to access and spread to and within the CNS toward the brain stem and spinal cord and studied in cell culture the underlying modes of intercellular propagation to better understand its neuropathogenesis. Our data suggest that axonal transport governs HCoV OC43 egress in the CNS, leading to the exacerbation of neuropathogenesis. Exploiting knowledge on neuroinvasion and dissemination will enhance our ability to control viral infection within the CNS, as it will shed light on underlying mechanisms of neuropathogenesis and uncover potential druggable molecular virus-host interfaces.
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65
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Balasubramanian S, Peery RB, Minshull J, Lee M, White R, Kelly RM, Barnard GC. Generation of High Expressing Chinese Hamster Ovary Cell Pools Using the Leap-In Transposon System. Biotechnol J 2018; 13:e1700748. [DOI: 10.1002/biot.201700748] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 03/29/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Sowmya Balasubramanian
- Bioprocess Research and Development; Eli Lilly and Company; LTC-North, 1200 Kentucky AvenueIndianapolis IN 46221 USA
| | - Robert B. Peery
- Biotechnology Discovery Research; Lilly Research Laboratories; Eli Lilly and Company; Lilly Corporate Center; Indianapolis IN 46225 USA
| | | | - Maggie Lee
- ATUM; 37950 Central CtNewark CA 94560 USA
| | - Regina White
- Biotechnology Discovery Research; Lilly Research Laboratories; Eli Lilly and Company; Lilly Corporate Center; Indianapolis IN 46225 USA
| | - Ronan M. Kelly
- Bioprocess Research and Development; Eli Lilly and Company; LTC-North, 1200 Kentucky AvenueIndianapolis IN 46221 USA
| | - Gavin C. Barnard
- Biotechnology Discovery Research; Lilly Research Laboratories; Eli Lilly and Company; Lilly Corporate Center; Indianapolis IN 46225 USA
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66
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Wagner JM, Williams EV, Alper HS. Developing a piggyBac Transposon System and Compatible Selection Markers for Insertional Mutagenesis and Genome Engineering in Yarrowia lipolytica. Biotechnol J 2018; 13:e1800022. [PMID: 29493878 DOI: 10.1002/biot.201800022] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 02/17/2018] [Indexed: 12/30/2022]
Abstract
Yarrowia lipolytica is a non-conventional yeast of interest to the biotechnology industry. However, the physiology, metabolism, and genetic regulation of Y. lipolytica diverge significantly from more well-studied and characterized yeasts such as Saccharomyces cerevisiae. To develop additional genetic tools for this industrially relevant host, the piggyBac transposon system to enable efficient generation of genome-wide insertional mutagenesis libraries and introduction of scarless, footprint-free genomic modifications in Y. lipolytica. Specifically, we demonstrate piggyBac transposition in Y. lipolytica, and then use the approach to screen transposon insertion libraries for rapid isolation of mutations that confer altered canavanine resistance, pigment formation, and neutral lipid accumulation. We also develop a variety of piggyBac compatible selection markers for footprint-free genome engineering, including a novel dominant marker cassette (Escherichia coli guaB) for effective Y. lipolytica selection using mycophenolic acid. We utilize these marker cassettes to construct a piggyBac vector set that allows for auxotrophic selection (uracil or tryptophan biosynthesis) or dominant selection (hygromycin, nourseothricin, chlorimuron ethyl, or mycophenolic acid resistance) and subsequent marker excision. These new genetic tools and techniques will help to facilitate and accelerate the engineering of Y. lipolytica strains for efficient and sustainable production of a wide variety of small molecules and proteins.
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Affiliation(s)
- James M Wagner
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712, USA
| | - Eden V Williams
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712, USA
| | - Hal S Alper
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712, USA
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, 2500 Speedway Avenue, Austin, TX 78712, USA
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67
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Taschner M, Lorentzen A, Mourão A, Collins T, Freke GM, Moulding D, Basquin J, Jenkins D, Lorentzen E. Crystal structure of intraflagellar transport protein 80 reveals a homo-dimer required for ciliogenesis. eLife 2018; 7:33067. [PMID: 29658880 PMCID: PMC5931796 DOI: 10.7554/elife.33067] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 04/13/2018] [Indexed: 12/16/2022] Open
Abstract
Oligomeric assemblies of intraflagellar transport (IFT) particles build cilia through sequential recruitment and transport of ciliary cargo proteins within cilia. Here we present the 1.8 Å resolution crystal structure of the Chlamydomonas IFT-B protein IFT80, which reveals the architecture of two N-terminal β-propellers followed by an α-helical extension. The N-terminal β-propeller tethers IFT80 to the IFT-B complex via IFT38 whereas the second β-propeller and the C-terminal α-helical extension result in IFT80 homo-dimerization. Using CRISPR/Cas to create biallelic Ift80 frameshift mutations in IMCD3 mouse cells, we demonstrate that IFT80 is absolutely required for ciliogenesis. Structural mapping and rescue experiments reveal that human disease-causing missense mutations do not cluster within IFT80 and form functional IFT particles. Unlike missense mutant forms of IFT80, deletion of the C-terminal dimerization domain prevented rescue of ciliogenesis. Taken together our results may provide a first insight into higher order IFT complex formation likely required for IFT train formation.
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Affiliation(s)
- Michael Taschner
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Anna Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - André Mourão
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Toby Collins
- Genetics and Genomic Medicine, University College London, London, United Kingdom
| | - Grace M Freke
- Genetics and Genomic Medicine, University College London, London, United Kingdom
| | - Dale Moulding
- Developmental Biology and Cancer Programmes, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Jerome Basquin
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - Dagan Jenkins
- Genetics and Genomic Medicine, University College London, London, United Kingdom
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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68
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Michael IP, Nagy A. Inducible Protein Production in 293 Cells Using the piggyBac Transposon System. Methods Mol Biol 2018; 1850:57-68. [PMID: 30242680 DOI: 10.1007/978-1-4939-8730-6_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Recombinant proteins are widely used to study various pathophysiological processes. Nevertheless, the establishment of the desired protein-producing stable mammalian cell lines using traditional methods is hampered by multiple laborious steps. In this chapter, we describe a simple and robust system that allows for the derivation of stable transgenic cell lines in 293 cells, yielding high protein expression levels, in a short time period. This methodology is based on the piggyBac transposon system and, notably, it allows for inducible production of the protein of interest. Moreover, it can easily be used in conventional laboratory cell culture settings and does not require any specialized devices. Herein, we outline all the steps of this procedure in detail and point out specific considerations.
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Affiliation(s)
- Iacovos P Michael
- Swiss Institute for Experimental Cancer Research, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | - Andras Nagy
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Department of Obstetrics and Gynaecology, Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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69
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Preclinical and clinical advances in transposon-based gene therapy. Biosci Rep 2017; 37:BSR20160614. [PMID: 29089466 PMCID: PMC5715130 DOI: 10.1042/bsr20160614] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 10/26/2017] [Accepted: 10/30/2017] [Indexed: 02/08/2023] Open
Abstract
Transposons derived from Sleeping Beauty (SB), piggyBac (PB), or Tol2 typically require cotransfection of transposon DNA with a transposase either as an expression plasmid or mRNA. Consequently, this results in genomic integration of the potentially therapeutic gene into chromosomes of the desired target cells, and thus conferring stable expression. Non-viral transfection methods are typically preferred to deliver the transposon components into the target cells. However, these methods do not match the efficacy typically attained with viral vectors and are sometimes associated with cellular toxicity evoked by the DNA itself. In recent years, the overall transposition efficacy has gradually increased by codon optimization of the transposase, generation of hyperactive transposases, and/or introduction of specific mutations in the transposon terminal repeats. Their versatility enabled the stable genetic engineering in many different primary cell types, including stem/progenitor cells and differentiated cell types. This prompted numerous preclinical proof-of-concept studies in disease models that demonstrated the potential of DNA transposons for ex vivo and in vivo gene therapy. One of the merits of transposon systems relates to their ability to deliver relatively large therapeutic transgenes that cannot readily be accommodated in viral vectors such as full-length dystrophin cDNA. These emerging insights paved the way toward the first transposon-based phase I/II clinical trials to treat hematologic cancer and other diseases. Though encouraging results were obtained, controlled pivotal clinical trials are needed to corroborate the efficacy and safety of transposon-based therapies.
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70
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Wong AHM, Tomlinson ACA, Zhou D, Satkunarajah M, Chen K, Sharon C, Desforges M, Talbot PJ, Rini JM. Receptor-binding loops in alphacoronavirus adaptation and evolution. Nat Commun 2017; 8:1735. [PMID: 29170370 PMCID: PMC5701055 DOI: 10.1038/s41467-017-01706-x] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 10/06/2017] [Indexed: 02/08/2023] Open
Abstract
RNA viruses are characterized by a high mutation rate, a buffer against environmental change. Nevertheless, the means by which random mutation improves viral fitness is not well characterized. Here we report the X-ray crystal structure of the receptor-binding domain (RBD) of the human coronavirus, HCoV-229E, in complex with the ectodomain of its receptor, aminopeptidase N (APN). Three extended loops are solely responsible for receptor binding and the evolution of HCoV-229E and its close relatives is accompanied by changing loop–receptor interactions. Phylogenetic analysis shows that the natural HCoV-229E receptor-binding loop variation observed defines six RBD classes whose viruses have successively replaced each other in the human population over the past 50 years. These RBD classes differ in their affinity for APN and their ability to bind an HCoV-229E neutralizing antibody. Together, our results provide a model for alphacoronavirus adaptation and evolution based on the use of extended loops for receptor binding. Coronaviruses have a relatively high mutation rate, potentially allowing fast adaptation to changing pressures. Here, Wong et al. provide the structure of the receptor-binding domain (RBD) of the human coronavirus HCoV-229E and its receptor and analyze the evolution of the RBD over the past 50 years.
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Affiliation(s)
- Alan H M Wong
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Aidan C A Tomlinson
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Dongxia Zhou
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Malathy Satkunarajah
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Kevin Chen
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Chetna Sharon
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Marc Desforges
- Laboratory of Neuroimmunovirology, INRS-Institut Armand-Frappier, Institut National de la Recherche Scientifique, Université du Québec, 531 Boulevard des Prairies, Laval, Québec, Canada, H7V 1B7
| | - Pierre J Talbot
- Laboratory of Neuroimmunovirology, INRS-Institut Armand-Frappier, Institut National de la Recherche Scientifique, Université du Québec, 531 Boulevard des Prairies, Laval, Québec, Canada, H7V 1B7
| | - James M Rini
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8. .,Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8.
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71
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Janune D, Abd El Kader T, Aoyama E, Nishida T, Tabata Y, Kubota S, Takigawa M. Novel role of CCN3 that maintains the differentiated phenotype of articular cartilage. J Bone Miner Metab 2017; 35:582-597. [PMID: 27853940 DOI: 10.1007/s00774-016-0793-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 09/25/2016] [Indexed: 02/07/2023]
Abstract
Knowledge of the microenvironment of articular cartilage in health and disease is the key to accomplishing fundamental disease-modifying treatments for osteoarthritis. The proteins comprising the CCN Family are matricellular proteins with a remarkable relevance within the context of cartilage metabolism. CCN2 displays a great capability for regenerating articular cartilage, and CCN3 has been shown to activate the expression of genes related to articular chondrocytes and to repress genes related to endochondral ossification in epiphyseal chondrocytes. Moreover, mice lacking CCN3 protein have been shown to display ostearthritic changes in their knee articular cartilage. In this study, we employed a monoiodoacetic acid (MIA)-induced osteoarthritic model to investigate whether osteoarthritic changes in the cartilage are reciprocally accompanied by CCN3 down-regulation and an inducible overexpression system to evaluate the effects of CCN3 on articular chondrocytes in vitro. Finally, we also investigated the effects of exogenous CCN3 in vivo during the early stages of MIA-induced osteoarthritis. We discovered that CCN3 is expressed by articular chondrocytes in normal rat knees, whereas it is rapidly down-regulated in osteoarthritic knees. In vitro, we also discovered that CCN3 increases the proteoglycan accumulation, the gene expression of type II collagen, tenascin-C and lubricin, as well as the protein production of tenascin-C and lubricin in articular chondrocytes. In vivo, it was discovered that exogenous CCN3 increased tidemark integrity and produced an increased production of lubricin protein. The potential utility of CCN3 as a future therapeutic agent and possible strategies to improve its therapeutic functions are also discussed.
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Affiliation(s)
- Danilo Janune
- Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School, Okayama, Japan
- Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8525, Japan
| | - Tarek Abd El Kader
- Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School, Okayama, Japan
| | - Eriko Aoyama
- Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School, Okayama, Japan
| | - Takashi Nishida
- Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8525, Japan
| | - Yasuhiko Tabata
- Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
| | - Satoshi Kubota
- Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School, Okayama, Japan.
- Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8525, Japan.
| | - Masaharu Takigawa
- Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School, Okayama, Japan.
- Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8525, Japan.
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72
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Tipanee J, VandenDriessche T, Chuah MK. Transposons: Moving Forward from Preclinical Studies to Clinical Trials. Hum Gene Ther 2017; 28:1087-1104. [DOI: 10.1089/hum.2017.128] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Jaitip Tipanee
- Department of Gene Therapy and Regenerative Medicine, Free University of Brussels (VUB), Brussels, Belgium
| | - Thierry VandenDriessche
- Department of Gene Therapy and Regenerative Medicine, Free University of Brussels (VUB), Brussels, Belgium
- Center for Molecular and Vascular Biology, Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Marinee K. Chuah
- Department of Gene Therapy and Regenerative Medicine, Free University of Brussels (VUB), Brussels, Belgium
- Center for Molecular and Vascular Biology, Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
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73
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NEUROG1 Regulates CDK2 to Promote Proliferation in Otic Progenitors. Stem Cell Reports 2017; 9:1516-1529. [PMID: 29033307 PMCID: PMC5829327 DOI: 10.1016/j.stemcr.2017.09.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 09/13/2017] [Accepted: 09/14/2017] [Indexed: 12/23/2022] Open
Abstract
Loss of spiral ganglion neurons (SGNs) significantly contributes to hearing loss. Otic progenitor cell transplantation is a potential strategy to replace lost SGNs. Understanding how key transcription factors promote SGN differentiation in otic progenitors accelerates efforts for replacement therapies. A pro-neural transcription factor, Neurogenin1 (Neurog1), is essential for SGN development. Using an immortalized multipotent otic progenitor (iMOP) cell line that can self-renew and differentiate into otic neurons, NEUROG1 was enriched at the promoter of cyclin-dependent kinase 2 (Cdk2) and neurogenic differentiation 1 (NeuroD1) genes. Changes in H3K9ac and H3K9me3 deposition at the Cdk2 and NeuroD1 promoters suggested epigenetic regulation during iMOP proliferation and differentiation. In self-renewing iMOP cells, overexpression of NEUROG1 increased CDK2 to drive proliferation, while knockdown of NEUROG1 decreased CDK2 and reduced proliferation. In iMOP-derived neurons, overexpression of NEUROG1 accelerated acquisition of neuronal morphology, while knockdown of NEUROG1 prevented differentiation. Our findings suggest that NEUROG1 can promote proliferation or neuronal differentiation.
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74
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Structural basis of Notch O-glucosylation and O-xylosylation by mammalian protein-O-glucosyltransferase 1 (POGLUT1). Nat Commun 2017; 8:185. [PMID: 28775322 PMCID: PMC5543122 DOI: 10.1038/s41467-017-00255-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 06/14/2017] [Indexed: 11/08/2022] Open
Abstract
Protein O-glucosyltransferase 1/Rumi-mediated glucosylation of Notch epidermal growth factor-like (EGF-like) domains plays an important role in Notch signaling. Protein O-glucosyltransferase 1 shows specificity for folded EGF-like domains, it can only glycosylate serine residues in the C1XSXPC2 motif, and it possesses an uncommon dual donor substrate specificity. Using several EGF-like domains and donor substrate analogs, we have determined the structures of human Protein O-glucosyltransferase 1 substrate/product complexes that provide mechanistic insight into the basis for these properties. Notably, we show that Protein O-glucosyltransferase 1’s requirement for folded EGF-like domains also leads to its serine specificity and that two distinct local conformational states are likely responsible for its ability to transfer both glucose and xylose. We also show that Protein O-glucosyltransferase 1 possesses the potential to xylosylate a much broader range of EGF-like domain substrates than was previously thought. Finally, we show that Protein O-glucosyltransferase 1 has co-evolved with EGF-like domains of the type found in Notch. POGLUT1 is a protein-O-glucosyltransferase that transfers glucose and xylose to the EGF-like domains of Notch and other signaling receptors. Here the authors report the structure of human POGLUT1 in complexes with 3 different EGF-like domains and donor substrates and shed light on the enzyme’s substrate specificity and catalytic mechanism
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75
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Gu B, Lambert JP, Cockburn K, Gingras AC, Rossant J. AIRE is a critical spindle-associated protein in embryonic stem cells. eLife 2017; 6:e28131. [PMID: 28742026 PMCID: PMC5560860 DOI: 10.7554/elife.28131] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/17/2017] [Indexed: 12/21/2022] Open
Abstract
Embryonic stem (ES) cells go though embryo-like cell cycles regulated by specialized molecular mechanisms. However, it is not known whether there are ES cell-specific mechanisms regulating mitotic fidelity. Here we showed that Autoimmune Regulator (Aire), a transcription coordinator involved in immune tolerance processes, is a critical spindle-associated protein in mouse ES(mES) cells. BioID analysis showed that AIRE associates with spindle-associated proteins in mES cells. Loss of function analysis revealed that Aire was important for centrosome number regulation and spindle pole integrity specifically in mES cells. We also identified the c-terminal LESLL motif as a critical motif for AIRE's mitotic function. Combined maternal and zygotic knockout further revealed Aire's critical functions for spindle assembly in preimplantation embryos. These results uncovered a previously unappreciated function for Aire and provide new insights into the biology of stem cell proliferation and potential new angles to understand fertility defects in humans carrying Aire mutations.
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Affiliation(s)
- Bin Gu
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Canada
| | | | - Katie Cockburn
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Janet Rossant
- Program in Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
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76
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Poulain A, Perret S, Malenfant F, Mullick A, Massie B, Durocher Y. Rapid protein production from stable CHO cell pools using plasmid vector and the cumate gene-switch. J Biotechnol 2017. [PMID: 28625678 DOI: 10.1016/j.jbiotec.2017.06.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
To rapidly produce large amounts of recombinant proteins, the generation of stable Chinese Hamster Ovary (CHO) cell pools represents a useful alternative to large-scale transient gene expression (TGE). We have developed a cell line (CHOBRI/rcTA) allowing the inducible expression of recombinant proteins, based on the cumate gene switch. After the identification of optimal plasmid DNA topology (supercoiled vs linearized plasmid) for PEIpro™ mediated transfection and of optimal conditions for methionine sulfoximine (MSX) selection, we were able to generate CHOBRI/rcTA pools producing high levels of recombinant proteins. Volumetric productivities of up to 900mg/L were reproducibly achieved for a Fc fusion protein and up to 350mg/L for an antibody after 14days post-induction in non-optimized fed-batch cultures. In addition, we show that CHO pool volumetric productivities are not affected by a freeze-thaw cycle or following maintenance in culture for over one month in the presence of MSX. Finally, we demonstrate that volumetric protein production with the CR5 cumate-inducible promoter is three- to four-fold higher than with the human CMV or hybrid EF1α-HTLV constitutive promoters. These results suggest that the cumate-inducible CHOBRI/rcTA stable pool platform is a powerful and robust system for the rapid production of gram amounts of recombinant proteins.
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Affiliation(s)
- Adeline Poulain
- National Research Council of Canada, 6100 Royalmount Avenue, Montréal, QC H4P 2R2, Canada; Département de Microbiologie et Immunologie, Faculté de Médecine, Université de Montréal, QC, Canada
| | - Sylvie Perret
- National Research Council of Canada, 6100 Royalmount Avenue, Montréal, QC H4P 2R2, Canada
| | - Félix Malenfant
- National Research Council of Canada, 6100 Royalmount Avenue, Montréal, QC H4P 2R2, Canada
| | - Alaka Mullick
- National Research Council of Canada, 6100 Royalmount Avenue, Montréal, QC H4P 2R2, Canada
| | - Bernard Massie
- National Research Council of Canada, 6100 Royalmount Avenue, Montréal, QC H4P 2R2, Canada; Département de Microbiologie et Immunologie, Faculté de Médecine, Université de Montréal, QC, Canada
| | - Yves Durocher
- National Research Council of Canada, 6100 Royalmount Avenue, Montréal, QC H4P 2R2, Canada; Département de Biochimie et Médecine Moléculaire, Faculté de Médecine, Université de Montréal, QC, Canada.
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77
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Recognition of EGF-like domains by the Notch-modifying O-fucosyltransferase POFUT1. Nat Chem Biol 2017; 13:757-763. [DOI: 10.1038/nchembio.2381] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 02/21/2017] [Indexed: 01/17/2023]
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78
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Conway JRW, Warren SC, Timpson P. Context-dependent intravital imaging of therapeutic response using intramolecular FRET biosensors. Methods 2017; 128:78-94. [PMID: 28435000 DOI: 10.1016/j.ymeth.2017.04.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/13/2017] [Accepted: 04/08/2017] [Indexed: 12/18/2022] Open
Abstract
Intravital microscopy represents a more physiologically relevant method for assessing therapeutic response. However, the movement into an in vivo setting brings with it several additional considerations, the primary being the context in which drug activity is assessed. Microenvironmental factors, such as hypoxia, pH, fibrosis, immune infiltration and stromal interactions have all been shown to have pronounced effects on drug activity in a more complex setting, which is often lost in simpler two- or three-dimensional assays. Here we present a practical guide for the application of intravital microscopy, looking at the available fluorescent reporters and their respective expression systems and analysis considerations. Moving in vivo, we also discuss the microscopy set up and methods available for overlaying microenvironmental context to the experimental readouts. This enables a smooth transition into applying higher fidelity intravital imaging to improve the drug discovery process.
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Affiliation(s)
- James R W Conway
- Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Division, Sydney, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, University of NSW, Sydney, NSW 2010, Australia
| | - Sean C Warren
- Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Division, Sydney, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, University of NSW, Sydney, NSW 2010, Australia
| | - Paul Timpson
- Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Division, Sydney, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, University of NSW, Sydney, NSW 2010, Australia.
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79
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Keir LS, Firth R, Aponik L, Feitelberg D, Sakimoto S, Aguilar E, Welsh GI, Richards A, Usui Y, Satchell SC, Kuzmuk V, Coward RJ, Goult J, Bull KR, Sharma R, Bharti K, Westenskow PD, Michael IP, Saleem MA, Friedlander M. VEGF regulates local inhibitory complement proteins in the eye and kidney. J Clin Invest 2017; 127:199-214. [PMID: 27918307 PMCID: PMC5199702 DOI: 10.1172/jci86418] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 10/28/2016] [Indexed: 12/15/2022] Open
Abstract
Outer retinal and renal glomerular functions rely on specialized vasculature maintained by VEGF that is produced by neighboring epithelial cells, the retinal pigment epithelium (RPE) and podocytes, respectively. Dysregulation of RPE- and podocyte-derived VEGF is associated with neovascularization in wet age-related macular degeneration (ARMD), choriocapillaris degeneration, and glomerular thrombotic microangiopathy (TMA). Since complement activation and genetic variants in inhibitory complement factor H (CFH) are also features of both ARMD and TMA, we hypothesized that VEGF and CFH interact. Here, we demonstrated that VEGF inhibition decreases local CFH and other complement regulators in the eye and kidney through reduced VEGFR2/PKC-α/CREB signaling. Patient podocytes and RPE cells carrying disease-associated CFH genetic variants had more alternative complement pathway deposits than controls. These deposits were increased by VEGF antagonism, a common wet ARMD treatment, suggesting that VEGF inhibition could reduce cellular complement regulatory capacity. VEGF antagonism also increased markers of endothelial cell activation, which was partially reduced by genetic complement inhibition. Together, these results suggest that VEGF protects the retinal and glomerular microvasculature, not only through VEGFR2-mediated vasculotrophism, but also through modulation of local complement proteins that could protect against complement-mediated damage. Though further study is warranted, these findings could be relevant for patients receiving VEGF antagonists.
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Affiliation(s)
- Lindsay S. Keir
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Rachel Firth
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Lyndsey Aponik
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Daniel Feitelberg
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Susumu Sakimoto
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Edith Aguilar
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Gavin I. Welsh
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Anna Richards
- Queens Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Yoshihiko Usui
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
- Tokyo Medical University Hospital, Tokyo, Japan
| | - Simon C. Satchell
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Valeryia Kuzmuk
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Richard J. Coward
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Jonathan Goult
- Centre for Cellular and Molecular Physiology, University of Oxford, United Kingdom
| | - Katherine R. Bull
- Centre for Cellular and Molecular Physiology, University of Oxford, United Kingdom
| | - Ruchi Sharma
- National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Kapil Bharti
- National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Peter D. Westenskow
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
- The Lowy Medical Research Institute, La Jolla, California, USA
| | | | - Moin A. Saleem
- Academic Renal Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Martin Friedlander
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
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80
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Functional Interplay Between Murine Leukemia Virus Glycogag, Serinc5, and Surface Glycoprotein Governs Virus Entry, with Opposite Effects on Gammaretroviral and Ebolavirus Glycoproteins. mBio 2016; 7:mBio.01985-16. [PMID: 27879338 PMCID: PMC5120145 DOI: 10.1128/mbio.01985-16] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gammaretroviruses, such as murine leukemia viruses (MLVs), encode, in addition to the canonical Gag, Pol, and Env proteins that will form progeny virus particles, a protein called “glycogag” (glycosylated Gag). MLV glycogag contains the entire Gag sequence plus an 88-residue N-terminal extension. It has recently been reported that glycogag, like the Nef protein of HIV-1, counteracts the antiviral effects of the cellular protein Serinc5. We have found, in agreement with prior work, that glycogag strongly enhances the infectivity of MLVs with some Env proteins but not those with others. In contrast, however, glycogag was detrimental to MLVs carrying Ebolavirus glycoprotein. Glycogag could be replaced, with respect to viral infectivity, by the unrelated S2 protein of equine infectious anemia virus. We devised an assay for viral entry in which virus particles deliver the Cre recombinase into cells, leading to the expression of a reporter. Data from this assay showed that both the positive and the negative effects of glycogag and S2 upon MLV infectivity are exerted at the level of virus entry. Moreover, transfection of the virus-producing cells with a Serinc5 expression plasmid reduced the infectivity and entry capability of MLV carrying xenotropic MLV Env, particularly in the absence of glycogag. Conversely, Serinc5 expression abrogated the negative effects of glycogag upon the infectivity and entry capability of MLV carrying Ebolavirus glycoprotein. As Serinc5 may influence cellular phospholipid metabolism, it seems possible that all of these effects on virus entry derive from changes in the lipid composition of viral membranes. Many murine leukemia viruses (MLVs) encode a protein called “glycogag.” The function of glycogag is not fully understood, but it can assist HIV-1 replication in the absence of the HIV-1 protein Nef under some circumstances. In turn, Nef counteracts the cellular protein Serinc5. Glycogag enhances the infectivity of MLVs with some but not all MLV Env proteins (which mediate viral entry into the host cell upon binding to cell surface receptors). We now report that glycogag acts by enhancing viral entry and that, like Nef, glycogag antagonizes Serinc5. Surprisingly, the effects of glycogag and Serinc5 upon the entry and infectivity of MLV particles carrying an Ebolavirus glycoprotein are the opposite of those observed with the MLV Env proteins. The unrelated S2 protein of equine infectious anemia virus (EIAV) is functionally analogous to glycogag in our experiments. Thus, three retroviruses (HIV-1, MLV, and EIAV) have independently evolved accessory proteins that counteract Serinc5.
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81
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In Vitro Transfection with and Expression of CCN Family of Genes. Methods Mol Biol 2016. [PMID: 27734370 DOI: 10.1007/978-1-4939-6430-7_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The ability to engineer cells to express a protein of interest in an inducible manner and stably for a long period is a valuable tool in molecular biology and also one that holds promise for regenerative medicine in the future. CCN proteins have been suggested to be involved in tissue regeneration. In this chapter, we describe an in vitro method for stable and inducible expression of CCN protein in a chondroprogenitor cell line and in chondrocytes in primary culture that does not involve the use of any viral vector.
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82
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Ploier B, Caro LN, Morizumi T, Pandey K, Pearring JN, Goren MA, Finnemann SC, Graumann J, Arshavsky VY, Dittman JS, Ernst OP, Menon AK. Dimerization deficiency of enigmatic retinitis pigmentosa-linked rhodopsin mutants. Nat Commun 2016; 7:12832. [PMID: 27694816 PMCID: PMC5059438 DOI: 10.1038/ncomms12832] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 08/03/2016] [Indexed: 02/05/2023] Open
Abstract
Retinitis pigmentosa (RP) is a blinding disease often associated with mutations in rhodopsin, a light-sensing G protein-coupled receptor and phospholipid scramblase. Most RP-associated mutations affect rhodopsin's activity or transport to disc membranes. Intriguingly, some mutations produce apparently normal rhodopsins that nevertheless cause disease. Here we show that three such enigmatic mutations—F45L, V209M and F220C—yield fully functional visual pigments that bind the 11-cis retinal chromophore, activate the G protein transducin, traffic to the light-sensitive photoreceptor compartment and scramble phospholipids. However, tests of scramblase activity show that unlike wild-type rhodopsin that functionally reconstitutes into liposomes as dimers or multimers, F45L, V209M and F220C rhodopsins behave as monomers. This result was confirmed in pull-down experiments. Our data suggest that the photoreceptor pathology associated with expression of these enigmatic RP-associated pigments arises from their unexpected inability to dimerize via transmembrane helices 1 and 5. Retinitis pigmentosa is often caused by mutations that affect the activity or transport of rhodopsin, but some mutations cause disease even though an apparently functional protein is produced. Here the authors show that three such enigmatic mutants retain scramblase activity but are unable to dimerize.
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Affiliation(s)
- Birgit Ploier
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10065, USA
| | - Lydia N Caro
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Takefumi Morizumi
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Kalpana Pandey
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10065, USA
| | - Jillian N Pearring
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Michael A Goren
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10065, USA
| | - Silvia C Finnemann
- Department of Biological Sciences, Center for Cancer, Genetic Diseases and Gene Regulation, Fordham University, Bronx, New York 10458, USA
| | - Johannes Graumann
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10065, USA.,Weill Cornell Medicine-Qatar, Qatar Foundation, Education City P.O.Box 24144, Doha, State of Qatar
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710, USA.,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Jeremy S Dittman
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10065, USA
| | - Oliver P Ernst
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10065, USA
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83
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Lin YH, Chang KY. Rational design of a synthetic mammalian riboswitch as a ligand-responsive -1 ribosomal frame-shifting stimulator. Nucleic Acids Res 2016; 44:9005-9015. [PMID: 27521370 PMCID: PMC5062990 DOI: 10.1093/nar/gkw718] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 08/03/2016] [Indexed: 12/18/2022] Open
Abstract
Metabolite-responsive RNA pseudoknots derived from prokaryotic riboswitches have been shown to stimulate −1 programmed ribosomal frameshifting (PRF), suggesting −1 PRF as a promising gene expression platform to extend riboswitch applications in higher eukaryotes. However, its general application has been hampered by difficulty in identifying a specific ligand-responsive pseudoknot that also functions as a ligand-dependent -1 PRF stimulator. We addressed this problem by using the −1 PRF stimulation pseudoknot of SARS-CoV (SARS-PK) to build a ligand-dependent −1 PRF stimulator. In particular, the extra stem of SARS-PK was replaced by an RNA aptamer of theophylline and designed to couple theophylline binding with the stimulation of −1 PRF. Conformational and functional analyses indicate that the engineered theophylline-responsive RNA functions as a mammalian riboswitch with robust theophylline-dependent −1 PRF stimulation activity in a stable human 293T cell-line. Thus, RNA–ligand interaction repertoire provided by in vitro selection becomes accessible to ligand-specific −1 PRF stimulator engineering using SARS-PK as the scaffold for synthetic biology application.
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Affiliation(s)
- Ya-Hui Lin
- Institute of Biochemistry, National Chung-Hsing University, 250 Kuo-Kung Road, Taichung, 402 Taiwan
| | - Kung-Yao Chang
- Institute of Biochemistry, National Chung-Hsing University, 250 Kuo-Kung Road, Taichung, 402 Taiwan
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84
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Wu Y, Zhang TY, Fang LL, Chen ZX, Song LW, Cao JL, Yang L, Yuan Q, Xia NS. Sleeping Beauty transposon-based system for rapid generation of HBV-replicating stable cell lines. J Virol Methods 2016; 234:96-100. [PMID: 27091097 DOI: 10.1016/j.jviromet.2016.04.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 04/14/2016] [Accepted: 04/15/2016] [Indexed: 01/12/2023]
Abstract
The stable HBV-replicating cell lines, which carry replication-competent HBV genome stably integrated into the genome of host cell, are widely used to evaluate the effects of antiviral agents. However, current methods to generate HBV-replicating cell lines, which are mostly dependent on random integration of foreign DNA via plasmid transfection, are less-efficient and time-consuming. To address this issue, we constructed an all-in-one Sleeping Beauty transposon system (denoted pTSMP-HBV vector) for robust generation of stable cell lines carrying replication-competent HBV genome of different genotype. This vector contains a Sleeping Beauty transposon containing HBV 1.3-copy genome with an expression cassette of the SV40 promoter driving red fluorescent protein (mCherry) and self-cleaving P2A peptide linked puromycin resistance gene (PuroR). In addition, a PGK promoter-driven SB100X hyperactive transposase cassette is placed in the outside of the transposon in the same plasmid.The HBV-replicating stable cells could be obtained from pTSMP-HBV transfected HepG2 cells by red fluorescence-activated cell sorting and puromycin resistant cell selection within 4-week. Using this system, we successfully constructed four cell lines carrying replication-competent HBV genome of genotypes A-D. The replication and viral protein expression profiles of these cells were systematically characterized. In conclusion, our study provides a high-efficiency strategy to generate HBV-replicating stable cell lines, which may facilitate HBV-related virological study.
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Affiliation(s)
- Yong Wu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China; National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Tian-Ying Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China; School of Life Science, Xiamen University, Xiamen 361102, China
| | - Lin-Lin Fang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China; National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Zi-Xuan Chen
- Affiliated Quanzhou First Hospital by Fujian Medical University, Fujian, China
| | - Liu-Wei Song
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China; School of Life Science, Xiamen University, Xiamen 361102, China
| | - Jia-Li Cao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China; School of Life Science, Xiamen University, Xiamen 361102, China
| | - Lin Yang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China; National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Quan Yuan
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China; National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen 361102, China.
| | - Ning-Shao Xia
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China; National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen 361102, China
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85
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Balasubramanian S, Wurm FM, Hacker DL. Multigene expression in stable CHO cell pools generated with the piggyBac transposon system. Biotechnol Prog 2016; 32:1308-1317. [DOI: 10.1002/btpr.2319] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 06/07/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Sowmya Balasubramanian
- Laboratory of Cellular Biotechnology (LBTC); École Polytechnique Fédérale de Lausanne (EPFL); Lausanne CH-1015 Switzerland
| | - Florian M. Wurm
- Laboratory of Cellular Biotechnology (LBTC); École Polytechnique Fédérale de Lausanne (EPFL); Lausanne CH-1015 Switzerland
| | - David L. Hacker
- Laboratory of Cellular Biotechnology (LBTC); École Polytechnique Fédérale de Lausanne (EPFL); Lausanne CH-1015 Switzerland
- Protein Expression Core Facility (PECF), École Polytechnique Fédérale de Lausanne (EPFL); Lausanne CH-1015 Switzerland
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86
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Rajendra Y, Peery RB, Barnard GC. Generation of stable Chinese hamster ovary pools yielding antibody titers of up to 7.6 g/L using the piggyBac transposon system. Biotechnol Prog 2016; 32:1301-1307. [DOI: 10.1002/btpr.2307] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 05/25/2016] [Indexed: 01/16/2023]
Affiliation(s)
- Yashas Rajendra
- Biotechnology Discovery Research, Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center; Indianapolis IN 46285
| | - Robert B. Peery
- Biotechnology Discovery Research, Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center; Indianapolis IN 46285
| | - Gavin C. Barnard
- Biotechnology Discovery Research, Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center; Indianapolis IN 46285
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87
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Xiong ZJ, Huang J, Poda G, Pomès R, Privé GG. Structure of Human Acid Sphingomyelinase Reveals the Role of the Saposin Domain in Activating Substrate Hydrolysis. J Mol Biol 2016; 428:3026-42. [PMID: 27349982 DOI: 10.1016/j.jmb.2016.06.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 06/14/2016] [Accepted: 06/16/2016] [Indexed: 11/29/2022]
Abstract
Acid sphingomyelinase (ASM) is a lysosomal phosphodiesterase that catalyzes the hydrolysis of sphingomyelin to produce ceramide and phosphocholine. While other lysosomal sphingolipid hydrolases require a saposin activator protein for full activity, the ASM polypeptide incorporates a built-in N-terminal saposin domain and does not require an external activator protein. Here, we report the crystal structure of human ASM and describe the organization of the three main regions of the enzyme: the N-terminal saposin domain, the proline-rich connector, and the catalytic domain. The saposin domain is tightly associated along an edge of the large, bowl-shaped catalytic domain and adopts an open form that exposes a hydrophobic concave surface approximately 30Å from the catalytic center. The calculated electrostatic potential of the enzyme is electropositive at the acidic pH of the lysosome, consistent with the strict requirement for the presence of acidic lipids in target membranes. Docking studies indicate that sphingomyelin binds with the ceramide-phosphate group positioned at the binuclear zinc center and molecular dynamic simulations indicate that the intrinsic flexibility of the saposin domain is important for monomer-dimer exchange and for membrane interactions. Overall, ASM uses a combination of electrostatic and hydrophobic interactions to cause local disruptions of target bilayers in order to bring the lipid headgroup to the catalytic center in a membrane-bound reaction.
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Affiliation(s)
- Zi-Jian Xiong
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Jingjing Huang
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Gennady Poda
- Drug Discovery, Ontario Institute for Cancer Research, Toronto, Ontario, Canada; Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Régis Pomès
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Molecular Structure and Function, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Gilbert G Privé
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Princess Margaret Cancer Centre, Toronto, Ontario, Canada.
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88
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Recombinant protein production from stable mammalian cell lines and pools. Curr Opin Struct Biol 2016; 38:129-36. [DOI: 10.1016/j.sbi.2016.06.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 06/06/2016] [Accepted: 06/06/2016] [Indexed: 11/23/2022]
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89
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Kook S, Wang P, Young LR, Schwake M, Saftig P, Weng X, Meng Y, Neculai D, Marks MS, Gonzales L, Beers MF, Guttentag S. Impaired Lysosomal Integral Membrane Protein 2-dependent Peroxiredoxin 6 Delivery to Lamellar Bodies Accounts for Altered Alveolar Phospholipid Content in Adaptor Protein-3-deficient pearl Mice. J Biol Chem 2016; 291:8414-27. [PMID: 26907692 PMCID: PMC4861416 DOI: 10.1074/jbc.m116.720201] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Indexed: 11/06/2022] Open
Abstract
The Hermansky Pudlak syndromes (HPS) constitute a family of disorders characterized by oculocutaneous albinism and bleeding diathesis, often associated with lethal lung fibrosis. HPS results from mutations in genes of membrane trafficking complexes that facilitate delivery of cargo to lysosome-related organelles. Among the affected lysosome-related organelles are lamellar bodies (LB) within alveolar type 2 cells (AT2) in which surfactant components are assembled, modified, and stored. AT2 from HPS patients and mouse models of HPS exhibit enlarged LB with increased phospholipid content, but the mechanism underlying these defects is unknown. We now show that AT2 in the pearl mouse model of HPS type 2 lacking the adaptor protein 3 complex (AP-3) fails to accumulate the soluble enzyme peroxiredoxin 6 (PRDX6) in LB. This defect reflects impaired AP-3-dependent trafficking of PRDX6 to LB, because pearl mouse AT2 cells harbor a normal total PRDX6 content. AP-3-dependent targeting of PRDX6 to LB requires the transmembrane protein LIMP-2/SCARB2, a known AP-3-dependent cargo protein that functions as a carrier for lysosomal proteins in other cell types. Depletion of LB PRDX6 in AP-3- or LIMP-2/SCARB2-deficient mice correlates with phospholipid accumulation in lamellar bodies and with defective intraluminal degradation of LB disaturated phosphatidylcholine. Furthermore, AP-3-dependent LB targeting is facilitated by protein/protein interaction between LIMP-2/SCARB2 and PRDX6 in vitro and in vivo Our data provide the first evidence for an AP-3-dependent cargo protein required for the maturation of LB in AT2 and suggest that the loss of PRDX6 activity contributes to the pathogenic changes in LB phospholipid homeostasis found HPS2 patients.
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Affiliation(s)
| | - Ping Wang
- From the Division of Neonatology and
| | - Lisa R Young
- Division of Pediatric Pulmonary Medicine, Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Michael Schwake
- the Department of Chemistry, Biochemistry III, University of Bielefeld, D-33615 Bielefeld, Germany
| | - Paul Saftig
- the Institute of Biochemistry, Christian-Albrechts-University, Olshausenstrasse 40, D-24098 Kiel, Germany
| | - Xialian Weng
- the Zhejiang University, Yuhangtang Road 866, Hangzhou 310058, China
| | - Ying Meng
- the Zhejiang University, Yuhangtang Road 866, Hangzhou 310058, China
| | - Dante Neculai
- the Zhejiang University, Yuhangtang Road 866, Hangzhou 310058, China
| | - Michael S Marks
- the Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, and the Departments of Pathology and Laboratory Medicine and of Physiology, and
| | - Linda Gonzales
- Division of Adult Pulmonary and Critical Care Medicine, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Michael F Beers
- Division of Adult Pulmonary and Critical Care Medicine, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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90
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Olmedillas López S, Garcia-Arranz M, Garcia-Olmo D, Liras A. Preliminary study on non-viral transfection of F9 (factor IX) gene by nucleofection in human adipose-derived mesenchymal stem cells. PeerJ 2016; 4:e1907. [PMID: 27114871 PMCID: PMC4841220 DOI: 10.7717/peerj.1907] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Accepted: 03/16/2016] [Indexed: 12/17/2022] Open
Abstract
Background. Hemophilia is a rare recessive X-linked disease characterized by a deficiency of coagulation factor VIII or factor IX. Its current treatment is merely palliative. Advanced therapies are likely to become the treatment of choice for the disease as they could provide a curative treatment. Methods. The present study looks into the use of a safe non-viral transfection method based on nucleofection to express and secrete human clotting factor IX (hFIX) where human adipose tissue derived mesenchymal stem cells were used as target cells in vitro studies and NOD. Cg-Prkdcscid Il2rgtm1Wjl/SzJ mice were used to analyze factor IX expression in vivo studies. Previously, acute liver injury was induced by an injected intraperitoneal dose of 500 mg/kg body weight of acetaminophen. Results. Nucleofection showed a percentage of positive cells ranging between 30.7% and 41.9% and a cell viability rate of 29.8%, and cells were shown to secrete amounts of hFIX between 36.8 and 71.9 ng/mL. hFIX levels in the blood of NSG mice injected with ASCs transfected with this vector, were 2.7 ng/mL 48 h after injection. Expression and secretion of hFIX were achieved both in vitro cell culture media and in vivo in the plasma of mice treated with the transfected ASCs. Such cells are capable of eventually migrating to a previously damaged target tissue (the liver) where they secrete hFIX, releasing it to the bloodstream over a period of at least five days from administration. Conclusions. The results obtained in the present study may form a preliminary basis for the establishment of a future ex vivo non-viral gene/cellular safe therapy protocol that may eventually contribute to advancing the treatment of hemophilia.
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Affiliation(s)
| | - Mariano Garcia-Arranz
- Health Research Institute-Jiménez Diaz Foundation (iiS-FJD), Madrid, Spain; Department of Surgery, School of Medicine, Autonoma University of Madrid, Spain
| | - Damian Garcia-Olmo
- Health Research Institute-Jiménez Diaz Foundation (iiS-FJD), Madrid, Spain; Department of Surgery, School of Medicine, Autonoma University of Madrid, Spain
| | - Antonio Liras
- Department of Physiology, School of Biology, Complutense University of Madrid, Spain; Victoria Eugenia Royal Hemophilia Foundation, Madrid, Spain; Health Research Institute-Hospital 12 de Octubre Foundation (iiS-i+12O), Madrid, Spain
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91
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Chen F, Becker A, LoTurco J. Overview of Transgenic Glioblastoma and Oligoastrocytoma CNS Models and Their Utility in Drug Discovery. ACTA ACUST UNITED AC 2016; 72:14.37.1-14.37.12. [PMID: 26995546 DOI: 10.1002/0471141755.ph1437s72] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Many animal models have been developed to investigate the sources of central nervous system (CNS) tumor heterogeneity. Reviewed in this unit is a recently developed CNS tumor model using the piggyBac transposon system delivered by in utero electroporation, in which sources of tumor heterogeneity can be conveniently studied. Their applications for studying CNS tumors and drug discovery are also reviewed. © 2016 by John Wiley & Sons, Inc.
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Affiliation(s)
- Fuyi Chen
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Conn.,Current address: Department of Neurology, Yale School of Medicine, New Haven, Conn
| | - Albert Becker
- Department of Neuropathology, University of Bonn Medical Center, Bonn, Germany
| | - Joseph LoTurco
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Conn
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92
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Construction of a hybrid β-hexosaminidase subunit capable of forming stable homodimers that hydrolyze GM2 ganglioside in vivo. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2016; 3:15057. [PMID: 26966698 PMCID: PMC4774620 DOI: 10.1038/mtm.2015.57] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 12/17/2015] [Indexed: 02/07/2023]
Abstract
Tay-Sachs or Sandhoff disease result from mutations in either the evolutionarily related HEXA or HEXB genes encoding respectively, the α- or β-subunits of β-hexosaminidase A (HexA). Of the three Hex isozymes, only HexA can interact with its cofactor, the GM2 activator protein (GM2AP), and hydrolyze GM2 ganglioside. A major impediment to establishing gene or enzyme replacement therapy based on HexA is the need to synthesize both subunits. Thus, we combined the critical features of both α- and β-subunits into a single hybrid µ-subunit that contains the α-subunit active site, the stable β-subunit interface and unique areas in each subunit needed to interact with GM2AP. To facilitate intracellular analysis and the purification of the µ-homodimer (HexM), CRISPR-based genome editing was used to disrupt the HEXA and HEXB genes in a Human Embryonic Kidney 293 cell line stably expressing the µ-subunit. In association with GM2AP, HexM was shown to hydrolyze a fluorescent GM2 ganglioside derivative both in cellulo and in vitro. Gene transfer studies in both Tay-Sachs and Sandhoff mouse models demonstrated that HexM expression reduced brain GM2 ganglioside levels.
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93
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Baser B, van den Heuvel J. Assembling Multi-subunit Complexes Using Mammalian Expression. ADVANCED TECHNOLOGIES FOR PROTEIN COMPLEX PRODUCTION AND CHARACTERIZATION 2016; 896:225-38. [DOI: 10.1007/978-3-319-27216-0_15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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94
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Comparison of three transposons for the generation of highly productive recombinant CHO cell pools and cell lines. Biotechnol Bioeng 2015; 113:1234-43. [DOI: 10.1002/bit.25888] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 10/30/2015] [Accepted: 11/16/2015] [Indexed: 01/01/2023]
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95
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Abstract
DNA transposons offer an efficient nonviral method of permanently modifying the genomes of mammalian cells. The piggyBac transposon system has proven effective in genomic engineering of mammalian cells for preclinical applications, including gene discovery, simultaneous multiplexed genome modification, animal transgenesis, gene transfer in vivo achieving long-term gene expression in animals, and the genetic modification of clinically relevant cell types, such as induced pluripotent stem cells and human T lymphocytes. piggyBac has many desirable features, including seamless excision of transposons from the genomic DNA and the potential to target integration events to desired DNA sequences. In this review, we explore these recent applications and also highlight the unique advantages of using piggyBac for developing new molecular therapeutic strategies.
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Affiliation(s)
- Lauren E Woodard
- Department of Veterans Affairs, Tennessee Valley Health System, Nashville, TN, USA; Department of Medicine, Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Matthew H Wilson
- Department of Veterans Affairs, Tennessee Valley Health System, Nashville, TN, USA; Department of Medicine, Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, TN, USA.
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96
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Abstract
G-protein-coupled receptors (GPCRs) signal primarily through G proteins or arrestins. Arrestin binding to GPCRs blocks G protein interaction and redirects signalling to numerous G-protein-independent pathways. Here we report the crystal structure of a constitutively active form of human rhodopsin bound to a pre-activated form of the mouse visual arrestin, determined by serial femtosecond X-ray laser crystallography. Together with extensive biochemical and mutagenesis data, the structure reveals an overall architecture of the rhodopsin-arrestin assembly in which rhodopsin uses distinct structural elements, including transmembrane helix 7 and helix 8, to recruit arrestin. Correspondingly, arrestin adopts the pre-activated conformation, with a ∼20° rotation between the amino and carboxy domains, which opens up a cleft in arrestin to accommodate a short helix formed by the second intracellular loop of rhodopsin. This structure provides a basis for understanding GPCR-mediated arrestin-biased signalling and demonstrates the power of X-ray lasers for advancing the frontiers of structural biology.
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97
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Büssow K. Stable mammalian producer cell lines for structural biology. Curr Opin Struct Biol 2015; 32:81-90. [DOI: 10.1016/j.sbi.2015.03.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 02/11/2015] [Accepted: 03/03/2015] [Indexed: 11/28/2022]
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98
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Rapid recombinant protein production from piggyBac transposon-mediated stable CHO cell pools. J Biotechnol 2015; 200:61-9. [DOI: 10.1016/j.jbiotec.2015.03.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/10/2015] [Accepted: 03/02/2015] [Indexed: 12/12/2022]
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99
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Liras A. Biological therapies for inherited diseases: social and bioethical considerations. Hemophilia as an example. Expert Opin Biol Ther 2015; 15:713-22. [PMID: 25826280 DOI: 10.1517/14712598.2015.1029451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION In hemophilia, advanced therapies are warranted from a conceptual and methodological standpoint. Current advanced therapy strategies are centered on the use of adeno-associated viral vectors, although problems related to immunogenicity and hepatotoxicity still remain. AREAS COVERED Future clinical trials will have to scrupulously observe international bioethical standards in terms of patient selection, particularly children. Patient recruitment rates are likely to remain low due to the stringent exclusion criteria usually imposed on the trial population regarding their hepatic and immunological markers and the presence of viral coinfection; and to the existence of an optimal palliative treatment. EXPERT OPINION Accordingly, the results obtained are likely to be of low statistical significance, which could hinder their application to clinical practice. Another important issue is the degree to which society embraces these new emerging therapies. The unfamiliarity of society with these new methods, together with the many unresolved questions about them that remain, may threaten their acceptance not only by society at large but also by health-care professionals, which would limit their translational application to clinical practice.
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Affiliation(s)
- Antonio Liras
- Complutense University of Madrid, Research Institute 12 October Hospital of Madrid, Department of Physiology , Madrid , Spain +34649907879 ;
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100
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Caro LN, Li Z, Balo AR, Van Eps N, Rini JM, Ernst OP. Rapid and facile recombinant expression of bovine rhodopsin in HEK293S GnTI(-) cells using a PiggyBac inducible system. Methods Enzymol 2015; 556:307-30. [PMID: 25857788 DOI: 10.1016/bs.mie.2015.01.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Rhodopsin is a class A G protein-coupled receptor (GPCR) that provides important insights into the structure and function of the GPCR superfamily. Bovine rhodopsin is widely used as a model for GPCRs and was the first GPCR whose X-ray crystal structure was solved. One of the advantages of rhodopsin is that it is abundant in native tissue, and as a result, milligram quantities can be purified from the retinal rod cells of bovine eyes. Nonetheless, the study of GPCR conformation and dynamics, e.g., by electron paramagnetic resonance or (19)F nuclear magnetic resonance spectroscopy, typically requires mutagenesis to enable site-directed labeling of the protein. Mutations are also of great importance as they can stabilize the receptor and can be necessary to study different receptor conformations. Recombinant production of rhodopsins for biophysical studies has been achieved in different systems, including mammalian, insect, and yeast cells in culture, and from Drosophila melanogaster and Caenorhabditis elegans tissue. The piggyBac (PB) transposon system is used for gene delivery into a variety of cell types (e.g., HEK293 and CHO cells, fibroblasts, stem cells) and living organisms (e.g., honeybees, pigs, chicken, mice). Recently, the PB transposon has been described as an efficient tool for inducible protein expression in HEK293T and HEK293S N-acetylglucosaminyltransferase I-deficient (GnTI(-)) cells. This chapter describes a protocol for using the PB-based system for inducible expression of bovine rhodopsin in HEK293S GnTI(-) cells. Using this protocol, we expressed and purified 26 rhodopsin mutants to be used for site-directed spin labeling.
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Affiliation(s)
- Lydia N Caro
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Zhijie Li
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Aidin R Balo
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Ned Van Eps
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - James M Rini
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
| | - Oliver P Ernst
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
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