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Echeazarra L, García Del Caño G, Barrondo S, González-Burguera I, Saumell-Esnaola M, Aretxabala X, López de Jesús M, Borrega-Román L, Mato S, Ledent C, Matute C, Goicolea MA, Sallés J. Fit-for-purpose based testing and validation of antibodies to amino- and carboxy-terminal domains of cannabinoid receptor 1. Histochem Cell Biol 2021; 156:479-502. [PMID: 34453219 PMCID: PMC8604870 DOI: 10.1007/s00418-021-02025-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2021] [Indexed: 12/16/2022]
Abstract
Specific and selective anti-CB1 antibodies are among the most powerful research tools to unravel the complex biological processes mediated by the CB1 receptor in both physiological and pathological conditions. However, low performance of antibodies remains a major source of inconsistency between results from different laboratories. Using a variety of techniques, including some of the most commonly accepted ones for antibody specificity testing, we identified three of five commercial antibodies against different regions of CB1 receptor as the best choice for specific end-use purposes. Specifically, an antibody against a long fragment of the extracellular amino tail of CB1 receptor (but not one against a short sequence of the extreme amino-terminus) detected strong surface staining when applied to live cells, whereas two different antibodies against an identical fragment of the extreme carboxy-terminus of CB1 receptor (but not one against an upstream peptide) showed acceptable performance on all platforms, although they behaved differently in immunohistochemical assays depending on the tissue fixation procedure used and showed different specificity in Western blot assays, which made each of them particularly suitable for one of those techniques. Our results provide a framework to interpret past and future results derived from the use of different anti-CB1 antibodies in the context of current knowledge about the CB1 receptor at the molecular level, and highlight the need for an adequate validation for specific purposes, not only before antibodies are placed on the market, but also before the decision to discontinue them is made.
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Affiliation(s)
- Leyre Echeazarra
- Departament of Physiology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain.,Bioaraba, Dispositivos Móviles para el Control de Enfermedades Crónicas, 01008, Vitoria-Gasteiz, Spain
| | - Gontzal García Del Caño
- Department of Neurosciences, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain. .,Bioaraba, Neurofarmacología Celular y Molecular, 01008, Vitoria-Gasteiz, Spain.
| | - Sergio Barrondo
- Department of Pharmacology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain.,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), 28029, Madrid, Spain.,Bioaraba, Neurofarmacología Celular y Molecular, 01008, Vitoria-Gasteiz, Spain
| | - Imanol González-Burguera
- Department of Neurosciences, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain.,Bioaraba, Neurofarmacología Celular y Molecular, 01008, Vitoria-Gasteiz, Spain
| | - Miquel Saumell-Esnaola
- Department of Pharmacology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain.,Bioaraba, Neurofarmacología Celular y Molecular, 01008, Vitoria-Gasteiz, Spain
| | - Xabier Aretxabala
- Department of Neurosciences, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain
| | - Maider López de Jesús
- Department of Pharmacology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain.,Bioaraba, Neurofarmacología Celular y Molecular, 01008, Vitoria-Gasteiz, Spain
| | - Leire Borrega-Román
- Department of Pharmacology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain.,Bioaraba, Neurofarmacología Celular y Molecular, 01008, Vitoria-Gasteiz, Spain
| | - Susana Mato
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain.,Multiple Sclerosis and Other Demyelinating Diseases Unit, Biocruces Bizkaia, Barakaldo, Spain
| | | | - Carlos Matute
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - María Aranzazu Goicolea
- Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain
| | - Joan Sallés
- Department of Pharmacology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain. .,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), 28029, Madrid, Spain. .,Bioaraba, Neurofarmacología Celular y Molecular, 01008, Vitoria-Gasteiz, Spain.
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2
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Yiu JHC, Cheung SWM, Cai J, Chan KS, Chen J, Cheong LY, Chau HT, Xu A, Li RHW, Woo CW. TLR5 Supports Development of Placental Labyrinthine Zone in Mice. Front Cell Dev Biol 2021; 9:711253. [PMID: 34395439 PMCID: PMC8356041 DOI: 10.3389/fcell.2021.711253] [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: 05/18/2021] [Accepted: 06/24/2021] [Indexed: 11/16/2022] Open
Abstract
Toll plays an important role in innate immunity and embryonic development in lower-ranked animals, but in mammals, the homolog toll-like receptors (TLR) are reported to facilitate postnatal development of immunity only. Here, we discovered a role of TLR5 in placental development. Tlr5 was highly transcribed during the placenta-forming and functional phases. TLR5 deletion led to a smaller placental labyrinthine zone and lower embryo weight, and the smaller size of embryo was overcorrected, resulting in a higher postnatal body weight. Examination of TLR5-deficient conceptus revealed a decrease in nuclear cAMP-response element-binding protein (CREB), mechanistic target of rapamycin (mTOR) and insulin growth factor-1 receptor (IGF1R) abundances in the placenta-forming phase. Non-flagellin-based TLR5 ligands were detected in serum of female mice and the overexpression of TLR5 alone was sufficient to induce CREB nuclear translocation and mTOR transcriptional activation in trophoblasts. Taken together, we uncovered the participation of TLR5 in the early placental formation in mice, unveiling a role of TLR in embryonic development in higher-ranked animals.
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Affiliation(s)
- Jensen H C Yiu
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Samson W M Cheung
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Jieling Cai
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Kam-Suen Chan
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Jing Chen
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Lai Yee Cheong
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Hau-Tak Chau
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Aimin Xu
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Raymond H W Li
- Department of Obstetrics and Gynecology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Connie W Woo
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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3
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Kummeling MT, Buijs JT, Wisse LJ, van Uhm JI, Elzevier HW, de Ruiter MC, Groenendijk PM. Initial report on distribution of β3-adrenoceptor in the human female urethra. Neurourol Urodyn 2019; 39:125-132. [PMID: 31609506 DOI: 10.1002/nau.24183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 09/25/2019] [Indexed: 11/12/2022]
Abstract
INTRODUCTION Past research has demonstrated that the urethral tonus is mainly under sympathetic control. Since 5 years, a beta 3-adrenoceptor (ADRB3) agonist is available in the treatment of overactive bladder syndrome. The presence of ADRB3 within the human urethra has not been demonstrated to date. Presence of ADRB3 in the urethra could influence urethral tonus. The aim of this study is to investigate the presence of ADRB3 in the human female urethra. MATERIAL AND METHODS We performed anatomical studies in five female specimens. Three specimens were obtained from the body donation program, two from female patients with muscle-invasive bladder cancer, where radical resection of bladder and urethra was performed. The urethra up till the bladder neck was separated from the rest of the bladder and freshly obtained for this study. For demonstrating ADRB3 expression, we used rabbit polyclonal anti-human ADRB3 LS-A4198. RESULTS Expression of ADBR3 was demonstrated in the epithelial layer of all urethral parts, except at the level of the meatus. The level of ADRB3 expression was highest in the mid urethra. There was no direct contact between ADRB3 and nerve tissue. ADRB3 expression was also demonstrated in the stratified muscle layer at the level of the external urethral sphincter. CONCLUSIONS This is the first study to demonstrate the expression of ADRB3 in the human female urethra. There is an absence of a direct connection between ADRB3 and nerve tissue.
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Affiliation(s)
- Maxime T Kummeling
- Department of Urology, Haaglanden Medisch Centrum, The Hague, The Netherlands
| | - Jeroen T Buijs
- Department of Urology, Leiden University Medical Center, Leiden, The Netherlands
| | - Lambertus J Wisse
- Department of Anatomy and Embryology, Leiden University Medical Center, Leiden, The Netherlands
| | - Janneke I van Uhm
- Department of Urology, Leiden University Medical Center, Leiden, The Netherlands
| | - Henk W Elzevier
- Department of Urology, Leiden University Medical Center, Leiden, The Netherlands
| | - Marco C de Ruiter
- Department of Anatomy and Embryology, Leiden University Medical Center, Leiden, The Netherlands
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4
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Brunner SM, Koller A, Stockinger J, Sternberg F, Leis S, Ernst F, Strasser P, Brodowicz B, Ebner S, Holub BS, Rauch I, Graf K, Lang R, Kofler B. Validation of antibody-based tools for galanin research. Peptides 2019; 120:170009. [PMID: 30196126 DOI: 10.1016/j.peptides.2018.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/02/2018] [Accepted: 08/22/2018] [Indexed: 12/17/2022]
Abstract
Antibodies are an integral biomedical tool, not only for research but also as therapeutic agents. However, progress can only be made with sensitive and specific antibodies. The regulatory (neuro)peptide galanin and its three endogenous receptors (GAL1-3-R) are widely distributed in the central and peripheral nervous systems, and in peripheral non-neuronal tissues. The galanin system has multiple biological functions, including feeding behavior, pain processing, nerve regeneration and inflammation, to name only a few. Galanin could serve as biomarker in these processes, and therefore its receptors are potential drug targets for various diseases. For that reason, it is of paramount interest to precisely measure galanin peptide levels in tissues and to determine the cellular and subcellular localization of galanin receptors. A plethora of antibodies and antibody-based tools, including radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) kits, are commercially available to detect galanin and its receptors. However, many of them lack rigorous validation which casts doubt on their specificity. A goal of the present study was to raise awareness of the importance of validation of antibodies and antibody-based tools, with a specific focus on the galanin system. To that end, we tested and report here about commercially available antibodies against galanin and galanin receptors that appear specific to us. Furthermore, we investigated the validity of commercially available galanin ELISA kits. As the tested ELISAs failed to meet the validation requirements, we developed and validated a specific sandwich ELISA which can be used to detect full-length galanin in human plasma.
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Affiliation(s)
- Susanne M Brunner
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Andreas Koller
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Julia Stockinger
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Felix Sternberg
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Stefan Leis
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, University Hospital of the Paracelsus Medical University, Ignaz-Harrer-Straße 79, 5020, Salzburg, Austria.
| | - Florian Ernst
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, University Hospital of the Paracelsus Medical University, Ignaz-Harrer-Straße 79, 5020, Salzburg, Austria.
| | - Peter Strasser
- University Institute for Medical & Chemical Laboratory Diagnostic, University Hospital of the Paracelsus Medical University, Ignaz-Harrer-Straße 79, 5020, Salzburg, Austria.
| | - Bernhard Brodowicz
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Sabine Ebner
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Barbara S Holub
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Isabella Rauch
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Kerstin Graf
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Roland Lang
- Department of Dermatology, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Barbara Kofler
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
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5
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Bobkov V, Arimont M, Zarca A, De Groof TWM, van der Woning B, de Haard H, Smit MJ. Antibodies Targeting Chemokine Receptors CXCR4 and ACKR3. Mol Pharmacol 2019; 96:753-764. [PMID: 31481460 DOI: 10.1124/mol.119.116954] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 07/03/2019] [Indexed: 12/19/2022] Open
Abstract
Dysregulation of the chemokine system is implicated in a number of autoimmune and inflammatory diseases, as well as cancer. Modulation of chemokine receptor function is a very promising approach for therapeutic intervention. Despite interest from academic groups and pharmaceutical companies, there are currently few approved medicines targeting chemokine receptors. Monoclonal antibodies (mAbs) and antibody-based molecules have been successfully applied in the clinical therapy of cancer and represent a potential new class of therapeutics targeting chemokine receptors belonging to the class of G protein-coupled receptors (GPCRs). Besides conventional mAbs, single-domain antibodies and antibody scaffolds are also gaining attention as promising therapeutics. In this review, we provide an extensive overview of mAbs, single-domain antibodies, and other antibody fragments targeting CXCR4 and ACKR3, formerly referred to as CXCR7. We discuss their unique properties and advantages over small-molecule compounds, and also refer to the molecules in preclinical and clinical development. We focus on single-domain antibodies and scaffolds and their utilization in GPCR research. Additionally, structural analysis of antibody binding to CXCR4 is discussed. SIGNIFICANCE STATEMENT: Modulating the function of GPCRs, and particularly chemokine receptors, draws high interest. A comprehensive review is provided for monoclonal antibodies, antibody fragments, and variants directed at CXCR4 and ACKR3. Their advantageous functional properties, versatile applications as research tools, and use in the clinic are discussed.
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Affiliation(s)
- Vladimir Bobkov
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules Medicines and Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (V.B., M.A., A.Z., T.W.M.D.G., M.J.S.); and argenx BVBA, Zwijnaarde, Belgium (V.B., B.W., H.H.)
| | - Marta Arimont
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules Medicines and Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (V.B., M.A., A.Z., T.W.M.D.G., M.J.S.); and argenx BVBA, Zwijnaarde, Belgium (V.B., B.W., H.H.)
| | - Aurélien Zarca
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules Medicines and Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (V.B., M.A., A.Z., T.W.M.D.G., M.J.S.); and argenx BVBA, Zwijnaarde, Belgium (V.B., B.W., H.H.)
| | - Timo W M De Groof
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules Medicines and Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (V.B., M.A., A.Z., T.W.M.D.G., M.J.S.); and argenx BVBA, Zwijnaarde, Belgium (V.B., B.W., H.H.)
| | - Bas van der Woning
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules Medicines and Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (V.B., M.A., A.Z., T.W.M.D.G., M.J.S.); and argenx BVBA, Zwijnaarde, Belgium (V.B., B.W., H.H.)
| | - Hans de Haard
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules Medicines and Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (V.B., M.A., A.Z., T.W.M.D.G., M.J.S.); and argenx BVBA, Zwijnaarde, Belgium (V.B., B.W., H.H.)
| | - Martine J Smit
- Division of Medicinal Chemistry, Amsterdam Institute for Molecules Medicines and Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (V.B., M.A., A.Z., T.W.M.D.G., M.J.S.); and argenx BVBA, Zwijnaarde, Belgium (V.B., B.W., H.H.)
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6
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Use of syngeneic cells expressing membrane-bound GM-CSF as an adjuvant to induce antibodies against native multi-pass transmembrane protein. Sci Rep 2019; 9:9931. [PMID: 31289297 PMCID: PMC6616555 DOI: 10.1038/s41598-019-45160-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 02/12/2019] [Indexed: 12/23/2022] Open
Abstract
Membrane antigens (mAgs) are important targets for the development of antibody (Ab) drugs. However, native mAgs are not easily prepared, causing difficulties in acquiring functional Abs. In this study, we present a platform in which human mAgs were expressed in native form on cell adjuvants made with membrane-bound cytokines that were then used immunize syngeneic mice directly. The membrane-bound cytokines were used as immune stimulators to enhance specific Ab responses against the desired mAgs. Then, mAgs-expressing xenogeneic cells were used for Ab characterization to reduce non-specific binding. We established cell adjuvants by expressing membrane-bound cytokines (mIL-2, mIL-18, or mGM-CSF) on BALB/3T3 cells, which were effective in stimulating splenocyte proliferation in vitro. We then transiently expressed ecotropic viral integration site 2B (EVI2B) on the adjuvants and used them to directly immunize BALB/c mice. We found that 3T3/mGM-CSF cells stimulated higher specific anti-EVI2B Ab response in the immunized mice than the other cell adjuvants. A G-protein coupled receptor (GPCR), CXCR2, was then transiently expressed on 3T3/mGM-CSF cell adjuvant to immunize mice. The immune serum exhibited relatively higher binding to xenogeneic 293 A/CXCR2 cells than 293 A cells (~3.5-fold). Several hybridoma clones also exhibited selective binding to 293 A/CXCR2 cells. Therefore, the cell adjuvant could preserve the native conformation of mAgs and exhibit anti-mAg Ab stimulatory ability, providing a more convenient and effective method to generate functional Abs, thus possibly accelerating Ab drug development.
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7
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Park M, Steinberg SF. Carvedilol Prevents Redox Inactivation of Cardiomyocyte Β 1-Adrenergic Receptors. JACC Basic Transl Sci 2018; 3:521-532. [PMID: 30175276 PMCID: PMC6116783 DOI: 10.1016/j.jacbts.2018.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 06/08/2018] [Accepted: 06/11/2018] [Indexed: 01/14/2023]
Abstract
The mechanism that leads to a decrease in β1-adrenergic receptor (β1AR) expression in the failing heart remains uncertain. This study shows that cardiomyocyte β1AR expression and isoproterenol responsiveness decrease in response to oxidative stress. Studies of mechanisms show that the redox-dependent decrease in β1AR expression is uniquely prevented by carvedilol and not other βAR ligands. Carvedilol also promotes the accumulation of N-terminally truncated β1ARs that confer protection against doxorubicin-induced apoptosis in association with activation of protein kinase B. The redox-induced molecular controls for cardiomyocyte β1ARs and pharmacologic properties of carvedilol identified in this study have important clinical and therapeutic implications.
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Key Words
- AKT
- AKT, protein kinase B
- CREB, cyclic adenosine monophosphate binding response element protein
- ERK, extracellular regulated kinase
- FL, full-length
- GFX, GF109203X
- GRK, G protein–coupled receptor kinase
- HF, heart failure
- PKA, protein kinase A
- PKC, protein kinase C
- PTX, pertussis toxin
- ROS, reactive oxygen species
- cAMP, cyclic adenosine monophosphate
- cardiomyocytes
- cardioprotection
- oxidant stress
- β1-adrenergic receptor
- βAR, β-adrenergic receptor
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Affiliation(s)
- Misun Park
- Department of Pharmacology, Columbia University, New York, New York
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8
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Park M, Reddy GR, Wallukat G, Xiang YK, Steinberg SF. β 1-adrenergic receptor O-glycosylation regulates N-terminal cleavage and signaling responses in cardiomyocytes. Sci Rep 2017; 7:7890. [PMID: 28801655 PMCID: PMC5554155 DOI: 10.1038/s41598-017-06607-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 06/15/2017] [Indexed: 11/09/2022] Open
Abstract
β1-adrenergic receptors (β1ARs) mediate catecholamine actions in cardiomyocytes by coupling to both Gs/cAMP-dependent and Gs-independent/growth-regulatory pathways. Structural studies of the β1AR define ligand-binding sites in the transmembrane helices and effector docking sites at the intracellular surface of the β1AR, but the extracellular N-terminus, which is a target for post-translational modifications, typically is ignored. This study identifies β1AR N-terminal O-glycosylation at Ser37/Ser41 as a mechanism that prevents β1AR N-terminal cleavage. We used an adenoviral overexpression strategy to show that both full-length/glycosylated β1ARs and N-terminally truncated glycosylation-defective β1ARs couple to cAMP and ERK-MAPK signaling pathways in cardiomyocytes. However, a glycosylation defect that results in N-terminal truncation stabilizes β1ARs in a conformation that is biased toward the cAMP pathway. The identification of O-glycosylation and N-terminal cleavage as novel structural determinants of β1AR responsiveness in cardiomyocytes could be exploited for therapeutic advantage.
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Affiliation(s)
- Misun Park
- Department of Pharmacology, Columbia University, New York, NY, USA
| | - Gopireddy R Reddy
- Department of Pharmacology, University of California at Davis, Davis, CA, USA
| | - Gerd Wallukat
- Experimental and Clinical Research Center, Charité Campus Buch and Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Yang K Xiang
- Department of Pharmacology, University of California at Davis, Davis, CA, USA.,VA Northern California Health Care System, Mather, CA, USA
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9
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Gray A, Sidhu S, Chandrasekera P, Hendriksen C, Borrebaeck C. Animal-Friendly Affinity Reagents: Replacing the Needless in the Haystack. Trends Biotechnol 2016; 34:960-969. [DOI: 10.1016/j.tibtech.2016.05.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 05/26/2016] [Accepted: 05/31/2016] [Indexed: 10/21/2022]
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10
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Danbolt NC, Zhou Y, Furness DN, Holmseth S. Strategies for immunohistochemical protein localization using antibodies: What did we learn from neurotransmitter transporters in glial cells and neurons. Glia 2016; 64:2045-2064. [PMID: 27458697 DOI: 10.1002/glia.23027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 06/19/2016] [Accepted: 06/21/2016] [Indexed: 12/11/2022]
Abstract
Immunocytochemistry and Western blotting are still major methods for protein localization, but they rely on the specificity of the antibodies. Validation of antibody specificity remains challenging mostly because ideal negative controls are often unavailable. Further, immunochemical labeling patterns are also influenced by a number of other factors such as postmortem changes, fixation procedures and blocking agents as well as the general assay conditions (e.g., buffers, temperature, etc.). Western blotting similarly depends on tissue collection and sample preparation as well as the electrophoretic separation, transfer to blotting membranes and the immunochemical probing of immobilized molecules. Publication of inaccurate information on protein distribution has downstream consequences for other researchers because the interpretation of physiological and pharmacological observations depends on information on where ion channels, receptors, enzymes or transporters are located. Despite numerous reports, some of which are strongly worded, erroneous localization data are being published. Here we describe the extent of the problem and illustrate the nature of the pitfalls with examples from studies of neurotransmitter transporters. We explain the importance of supplementing immunochemical observations with other measurements (e.g., mRNA levels and distribution, protein activity, mass spectrometry, electrophysiological recordings, etc.) and why quantitative considerations are integral parts of the quality control. Further, we propose a practical strategy for researchers who plan to embark on a localization study. We also share our thoughts about guidelines for quality control. GLIA 2016;64:2045-2064.
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Affiliation(s)
- Niels Christian Danbolt
- Neurotransporter Group, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
| | - Yun Zhou
- Neurotransporter Group, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - David N Furness
- School of Life Sciences, Keele University, Keele, Staffs, United Kingdom
| | - Silvia Holmseth
- Neurotransporter Group, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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11
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Darzynkiewicz Z, Zhao H, Zhang S, Marietta YL, Ernest YL, Zhang Z. Initiation and termination of DNA replication during S phase in relation to cyclins D1, E and A, p21WAF1, Cdt1 and the p12 subunit of DNA polymerase δ revealed in individual cells by cytometry. Oncotarget 2015; 6:11735-50. [PMID: 26059433 PMCID: PMC4494901 DOI: 10.18632/oncotarget.4149] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Accepted: 05/03/2015] [Indexed: 12/18/2022] Open
Abstract
During our recent studies on mechanism of the regulation of human DNA polymerase δ in preparation for DNA replication or repair, multiparameter imaging cytometry as exemplified by laser scanning cytometry (LSC) has been used to assess changes in expression of the following nuclear proteins associated with initiation of DNA replication: cyclin A, PCNA, Ki-67, p21(WAF1), DNA replication factor Cdt1 and the smallest subunit of DNA polymerase δ, p12. In the present review, rather than focusing on Pol δ, we emphasize the application of LSC in these studies and outline possibilities offered by the concurrent differential analysis of DNA replication in conjunction with expression of the nuclear proteins. A more extensive analysis of the data on a correlation between rates of EdU incorporation, likely reporting DNA replication, and expression of these proteins, is presently provided. New data, specifically on the expression of cyclin D1 and cyclin E with respect to EdU incorporation as well as on a relationship between expression of cyclin A vs. p21(WAF1) and Ki-67 vs. Cdt1, are also reported. Of particular interest is the observation that this approach makes it possible to assess the temporal sequence of degradation of cyclin D1, p21(WAF1), Cdt1 and p12, each with respect to initiation of DNA replication and with respect to each other. Also the sequence or reappearance of these proteins in G2 after termination of DNA replication is assessed. The reviewed data provide a more comprehensive presentation of potential markers, whose presence or absence marks the DNA replicating cells. Discussed is also usefulness of these markers as indicators of proliferative activity in cancer tissues that may bear information on tumor progression and have a prognostic value.
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Affiliation(s)
- Zbigniew Darzynkiewicz
- Brander Cancer Research Institute, Department of Pathology, New York Medical College, Valhalla, NY
| | - Hong Zhao
- Brander Cancer Research Institute, Department of Pathology, New York Medical College, Valhalla, NY
| | - Sufang Zhang
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY
| | - Y.W.T. Lee Marietta
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY
| | - Y.C. Lee Ernest
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY
| | - Zhongtao Zhang
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY
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12
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Schonbrunn A. Editorial: Antibody can get it right: confronting problems of antibody specificity and irreproducibility. Mol Endocrinol 2015; 28:1403-7. [PMID: 25184858 DOI: 10.1210/me.2014-1230] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Agnes Schonbrunn
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas 77225
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13
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Michel MC, Seifert R. Selectivity of pharmacological tools: implications for use in cell physiology. A review in the theme: Cell signaling: proteins, pathways and mechanisms. Am J Physiol Cell Physiol 2015; 308:C505-20. [PMID: 25631871 DOI: 10.1152/ajpcell.00389.2014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 01/24/2015] [Indexed: 01/08/2023]
Abstract
Pharmacological inhibitors are frequently used to identify the receptors, receptor subtypes, and associated signaling pathways involved in physiological cell responses. Based on the effects of such inhibitors conclusions are drawn about the involvement of their assumed target or lack thereof. While such inhibitors can be useful tools for a better physiological understanding, their uncritical use can lead to incorrect conclusions. This article reviews the concept of inhibitor selectivity and its implication for cell physiology. Specifically, we discuss the implications of using inhibitor vs. activator approaches, issues of direct vs. indirect pathway modulation, implications of inverse agonism and biased signaling, and those of orthosteric vs. allosteric, competitive vs. noncompetitive, and reversible vs. irreversible inhibition. Additional problems can result from inconsistent estimates of inhibitor potency and differences in potency between cell-free systems and intact cells. These concepts are illustrated by several examples of inhibitors displaying affinity for related but distinct targets or even unrelated targets. Of note, many of the issues being addressed are also applicable to genetic inhibition strategies. The main practical conclusion following from these concepts is that investigators should be critical in the choice of inhibitor, its concentrations, and its mode of application. When this advice is adhered to, small-molecule pharmacological inhibitors can be important experimental tools in the hand of physiologists.
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Affiliation(s)
- Martin C Michel
- Department of Pharmacology, Johannes Gutenberg University, Mainz, Germany; and
| | - Roland Seifert
- Department of Pharmacology, Hannover Medical School, Hannover, Germany
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14
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Griffiths G, Lucocq JM. Antibodies for immunolabeling by light and electron microscopy: not for the faint hearted. Histochem Cell Biol 2014; 142:347-60. [PMID: 25151300 PMCID: PMC4160575 DOI: 10.1007/s00418-014-1263-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2014] [Indexed: 11/30/2022]
Abstract
Reliable antibodies represent crucial tools in the arsenal of the cell biologist and using them to localize antigens for immunocytochemistry is one of their most important applications. However, antibody-antigen interactions are much more complex and unpredictable than suggested by the old 'lock and key' analogy, and the goal of trying to prove that an antibody is specific is far more difficult than is generally appreciated. Here, we discuss the problems associated with the very complicated issue of trying to establish that an antibody (and the results obtained with it) is specific for the immunolabeling approaches used in light or electron microscopy. We discuss the increasing awareness that significant numbers of commercial antibodies are often not up to the quality required. We provide guidelines for choosing and testing antibodies in immuno-EM. Finally, we describe how quantitative EM methods can be used to identify reproducible patterns of antibody labeling and also extract specific labeling distributions.
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Affiliation(s)
- Gareth Griffiths
- Institute of Biological Sciences, University of Oslo, Blindern, 0316, Oslo, Norway,
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15
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Abstract
Erythropoietin (Epo) is an essential hormone that binds and activates the Epo receptor (EpoR) resident on the surface of erythroid progenitor cells, thereby promoting erythropoiesis. Recombinant human erythropoietin has been used successfully for over 20 years to treat anemia in millions of patients. In addition to erythropoiesis, Epo has also been reported to have other effects, such as tissue protection and promotion of tumor cell growth or survival. This became of significant concern in 2003, when some clinical trials in cancer patients reported increased tumor progression and worse survival outcomes in patients treated with erythropoiesis-stimulating agents (ESAs). One of the potential mechanisms proffered to explain the observed safety issues was that functional EpoR was expressed in tumors and/or endothelial cells, and that ESAs directly stimulated tumor growth and/or antagonized tumor ablative therapies. Since then, numerous groups have performed further research evaluating this potential mechanism with conflicting data and conclusions. Here, we review the biology of endogenous Epo and EpoR expression and function in erythropoiesis, and evaluate the evidence pertaining to the expression of EpoR on normal nonhematopoietic and tumor cells.
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16
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Miersch S, Sidhu SS. Synthetic antibodies: concepts, potential and practical considerations. Methods 2012; 57:486-98. [PMID: 22750306 DOI: 10.1016/j.ymeth.2012.06.012] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 06/18/2012] [Accepted: 06/21/2012] [Indexed: 01/08/2023] Open
Abstract
The last 100 years of enquiry into the fundamental basis of humoral immunity has resulted in the identification of antibodies as key molecular sentinels responsible for the in vivo surveillance, neutralization and clearance of foreign substances. Intense efforts aimed at understanding and exploiting their exquisite molecular specificity have positioned antibodies as a cornerstone supporting basic research, diagnostics and therapeutic applications [1]. More recently, efforts have aimed to circumvent the limitations of developing antibodies in animals by developing wholly in vitro techniques for designing antibodies of tailored specificity. This has been realized with the advent of synthetic antibody libraries that possess diversity outside the scope of natural immune repertoires and are thus capable of yielding specificities not otherwise attainable. This review examines the convergence of technologies that have contributed to the development of combinatorial phage-displayed antibody libraries. It further explores the practical concepts that underlie phage display, antibody diversity and the methods used in the generation of and selection from phage-displayed synthetic antibody libraries, highlighting specific applications in which design approaches gave rise to specificities that could not easily be obtained with libraries based upon natural immune repertories.
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Affiliation(s)
- S Miersch
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada.
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17
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Sandow S, Grayson TH. 'Altered' mesenteric artery SK(Ca) : functional implications? Br J Pharmacol 2011; 163:1115-7; author reply 1118-21. [PMID: 21707589 DOI: 10.1111/j.1476-5381.2011.01262.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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18
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Hutchings CJ, Koglin M, Marshall FH. Therapeutic antibodies directed at G protein-coupled receptors. MAbs 2010; 2:594-606. [PMID: 20864805 DOI: 10.4161/mabs.2.6.13420] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are one of the most important classes of targets for small molecule drug discovery, but many current GPCRs of interest are proving intractable to small molecule discovery and may be better approached with bio-therapeutics. GPCRs are implicated in a wide variety of diseases where antibody therapeutics are currently used. These include inflammatory diseases such as rheumatoid arthritis and Crohn disease, as well as metabolic disease and cancer. Raising antibodies to GPCRs has been difficult due to problems in obtaining suitable antigen because GPCRs are often expressed at low levels in cells and are very unstable when purified. A number of new developments in over-expressing receptors, as well as formulating stable pure protein, are contributing to the growing interest in targeting GPCRs with antibodies. This review discusses the opportunities for targeting GPCRs with antibodies using these approaches and describes the therapeutic antibodies that are currently in clinical development.
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19
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Simpson-Haidaris PJ, Seweryniak KE, Spinelli SL, Garcia-Bates TM, Murant TI, Pollock SJ, Sime PJ, Phipps RP. A putative role for platelet-derived PPARγ in vascular homeostasis demonstrated by anti-PPARγ induction of bleeding, thrombocytopenia and compensatory megakaryocytopoiesis. J Biotechnol 2010; 150:417-27. [PMID: 20888877 DOI: 10.1016/j.jbiotec.2010.09.955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 09/16/2010] [Accepted: 09/23/2010] [Indexed: 01/11/2023]
Abstract
Widely known for its role in adipogenesis and energy metabolism, PPARγ also plays a role in platelet function. To further understand functions of platelet-derived PPARγ, we produced rabbit polyclonal (PoAbs) and mouse monoclonal (MoAbs) antibodies against PPARγ 14mer/19mer peptide-immunogens. Unexpectedly, our work produced two key findings. First, MoAbs but not PoAbs produced against PPARγ peptide-immunogens displayed antigenic crossreactivity with highly conserved PPARα and PPARβ/δ. Similarly, Santa Cruz PoAb sc-7196 was monospecific for PPARγ while MoAb sc-7273 crossreacted with PPARα and PPARβ/δ. Second, immunized rabbits and mice exhibited unusual pathology including cachexia, excessive bleeding, and low platelet counts leading to thrombocytopenia. Spleens from immunized mice were fatty, hemorrhagic and friable. Although passive administration of anti-PPARγ PoAbs failed to induce experimental thrombocytopenia, megakaryocytopoiesis was induced 4-8-fold in mouse spleens. Similarly, marrow megakaryocytopoiesis was enhanced 1.8-4-fold in immunized rabbits. These peptide-immunogens are 100% conserved in human, rabbit and mouse; thus, immune-mediated platelet destruction via crossreactivity with platelet-derived PPARγ likely caused bleeding, thrombocytopenia, and compensatory megakaryocytopoiesis. Such overt pathology would cause significant problems for large-scale production of anti-PPARγ PoAbs. Furthermore, a major pitfall associated with MoAb production against closely related molecules is that monoclonicity does not guarantee monospecificity, an issue worth further scientific scrutiny.
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Affiliation(s)
- Patricia J Simpson-Haidaris
- Department of Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY 14642, USA. pj
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20
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Abbott C, Huang G, Ellison AR, Chen C, Arora T, Szilvassy SJ, Wei P. Mouse monoclonal antibodies against human c-Mpl and characterization for flow cytometry applications. Hybridoma (Larchmt) 2010; 29:103-13. [PMID: 20443702 DOI: 10.1089/hyb.2009.0095] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mouse monoclonal antibodies (MAbs) against human c-Mpl, the cognate receptor for thrombopoietin (TPO), were generated using hybridoma technology and characterized by various assays to demonstrate their specificity and affinity. Two such MAbs, 1.6 and 1.75, were determined to be superior for flow cytometry studies and exhibited double-digit picomolar (pM) affinities to soluble human c-Mpl protein. Both MAbs specifically bound to cells engineered to overexpress human c-Mpl protein, immortalized human hematopoietic cell lines that express endogenous c-Mpl, primary human bone marrow and peripheral blood-derived CD34(+) cells, and purified human platelets. No binding was detected on cell lines that did not express c-Mpl. Receptor competition and siRNA knock-down studies further confirmed the specificity of antibodies 1.6 and 1.75 for human c-Mpl. In contrast to these newly generated MAbs, none of eight commercially available anti-c-Mpl antibodies tested were found to bind specifically to human c-Mpl and were thus shown to be unsuitable for flow cytometry studies. Monoclonal antibodies 1.6 and 1.75 will therefore be useful flow cytometry reagents to detect cell surface c-Mpl expression.
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Affiliation(s)
- Christina Abbott
- Department of Protein Sciences, Amgen Inc., Thousand Oaks, California, USA
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21
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deBruin C, Lincoln P, Hartley C, Shehabeldin A, Van G, Szilvassy SJ. Most purported antibodies to the human granulocyte colony-stimulating factor receptor are not specific. Exp Hematol 2010; 38:1022-35. [PMID: 20696205 DOI: 10.1016/j.exphem.2010.07.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 07/22/2010] [Accepted: 07/28/2010] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Antibodies to human granulocyte colony-stimulating factor receptor (HuG-CSFR) are widely available and have been used in numerous studies to evaluate the expression of this protein on normal and malignant cells of hematopoietic and nonhematopoietic origin. Spurred by recent studies that demonstrated that two commonly used antibodies against the erythropoietin and thrombopoietin receptors can in fact bind to completely unrelated and more broadly expressed proteins, we screened 27 commercially available monoclonal and polyclonal antibodies with claimed specificity to HuG-CSFR to determine if they are specific to this receptor. MATERIALS AND METHODS Antibodies were evaluated by Western blotting, flow cytometry, and immunohistochemistry using 293T cells engineered to overexpress HuG-CSFR protein, immortalized human hematopoietic cell lines expressing endogenous G-CSFR, and purified human neutrophils. RESULTS Only two monoclonal antibodies and one polyclonal antibody could be employed using defined Western blotting or flow cytometry protocols to detect G-CSFR protein in cell lysates or on the surface of cells that express G-CSFR messenger RNA with no binding to cells that did not express the gene. None of the antibodies were suitable for immunohistochemistry. Competitive inhibition with soluble G-CSFR extracellular domain and small inhibitory RNA-mediated knock-down of G-CSFR messenger RNA further demonstrated the limited specificity of these antibodies for HuG-CSFR expressed on the cell surface. CONCLUSIONS Most commercially available anti-HuG-CSFR antibodies do not bind specifically to this protein. These studies highlight the need for investigators to validate antibodies in their own systems to avoid the inadvertent use of nonspecifically binding antibodies that could lead, as exemplified in this case with a hematopoietic growth factor receptor, to erroneous conclusions about protein expression.
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Affiliation(s)
- Cortney deBruin
- Hematology/Oncology Research Therapeutic Area, and Department of Protein Sciences, Amgen Inc., Thousand Oaks, CA 91320, USA
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22
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Localisation of pre- and postsynaptic cholinergic markers in the human brain. Behav Brain Res 2010; 221:341-55. [PMID: 20170687 DOI: 10.1016/j.bbr.2010.02.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 02/10/2010] [Indexed: 12/20/2022]
Abstract
The cholinergic neurotransmission in the central nervous system plays an important role in modulating cognitive processes such as learning, memory, arousal and sleep as well as in modulating locomotor activity. Dysfunction of the central cholinergic system is involved in numerous neuropsychiatric diseases. This review will provide a synopsis on the regional localisation of cholinergic and cholinoceptive structures within the adult human brain. On the cholinergic site data based on the distribution of choline acetyltransferase-immunoreactive structures are in the focus, complemented by data from acetylcholinesterase and vesicular acetylcholine transporter studies. On the cholinoceptive site, the distribution and localisation of receptors that transduce the acetylcholine message, i.e. the muscarinic and the nicotinic acetylcholine receptors is summarized. In addition to these data obtained on post mortem brain an overview of markers which allow for the in vivo monitoring of the cholinergic system in the brain is given. The detailed knowledge on the distribution and localisation of cholinergic markers in human brain will provide further information on the cholinergic circuits of neurotransmission - a prerequisite for the interpretation of in vivo imaging data and the development of selective diagnostic and therapeutic compounds.
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23
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Zoga V, Kawano T, Liang MY, Bienengraeber M, Weihrauch D, McCallum B, Gemes G, Hogan Q, Sarantopoulos C. KATP channel subunits in rat dorsal root ganglia: alterations by painful axotomy. Mol Pain 2010; 6:6. [PMID: 20102598 PMCID: PMC2825500 DOI: 10.1186/1744-8069-6-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2009] [Accepted: 01/26/2010] [Indexed: 11/16/2022] Open
Abstract
Background ATP-sensitive potassium (KATP) channels in neurons mediate neuroprotection, they regulate membrane excitability, and they control neurotransmitter release. Because loss of DRG neuronal KATP currents is involved in the pathophysiology of pain after peripheral nerve injury, we characterized the distribution of the KATP channel subunits in rat DRG, and determined their alterations by painful axotomy using RT-PCR, immunohistochemistry and electron microscopy. Results PCR demonstrated Kir6.1, Kir6.2, SUR1 and SUR2 transcripts in control DRG neurons. Protein expression for all but Kir6.1 was confirmed by Western blots and immunohistochemistry. Immunostaining of these subunits was identified by fluorescent and confocal microscopy in plasmalemmal and nuclear membranes, in the cytosol, along the peripheral fibers, and in satellite glial cells. Kir6.2 co-localized with SUR1 subunits. Kir6.2, SUR1, and SUR2 subunits were identified in neuronal subpopulations, categorized by positive or negative NF200 or CGRP staining. KATP current recorded in excised patches was blocked by glybenclamide, but preincubation with antibody against SUR1 abolished this blocking effect of glybenclamide, confirming that the antibody targets the SUR1 protein in the neuronal plasmalemmal membrane. In the myelinated nerve fibers we observed anti-SUR1 immunostaining in regularly spaced funneled-shaped structures. These structures were identified by electron microscopy as Schmidt-Lanterman incisures (SLI) formed by the Schwann cells. Immunostaining against SUR1 and Kir6.2 colocalized with anti-Caspr at paranodal sites. DRG excised from rats made hyperalgesic by spinal nerve ligation exhibited similar staining against Kir6.2, SUR1 or SUR2 as DRG from controls, but showed decreased prevalence of SUR1 immunofluorescent NF200 positive neurons. In DRG and dorsal roots proximal to axotomy SLI were smaller and showed decreased SUR1 immunofluorescence. Conclusions We identified Kir6.2/SUR1 and Kir6.2/SUR2 KATP channels in rat DRG neuronal somata, peripheral nerve fibers, and glial satellite and Schwann cells, in both normal state and after painful nerve injury. This is the first report of KATP channels in paranodal sites adjacent to nodes of Ranvier and in the SLI of the Schwann cells. After painful axotomy KATP channels are downregulated in large, myelinated somata and also in SLI, which are also of smaller size compared to controls. Because KATP channels may have diverse functional roles in neurons and glia, further studies are needed to explore the potential of KATP channels as targets of therapies against neuropathic pain and neurodegeneration.
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Affiliation(s)
- Vasiliki Zoga
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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