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Olaniru OE, Cheng J, Ast J, Arvaniti A, Atanes P, Huang GC, King AJF, Jones PM, Broichhagen J, Hodson DJ, Persaud SJ. SNAP-tag-enabled super-resolution imaging reveals constitutive and agonist-dependent trafficking of GPR56 in pancreatic β-cells. Mol Metab 2021; 53:101285. [PMID: 34224919 PMCID: PMC8326393 DOI: 10.1016/j.molmet.2021.101285] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/19/2021] [Accepted: 06/28/2021] [Indexed: 12/25/2022] Open
Abstract
Objective Members of the adhesion G protein-coupled receptor (aGPCR) subfamily are important actors in metabolic processes, with GPR56 (ADGRG1) emerging as a possible target for type 2 diabetes therapy. GPR56 can be activated by collagen III, its endogenous ligand, and by a synthetic seven amino-acid peptide (TYFAVLM; P7) contained within the GPR56 Stachel sequence. However, the mechanisms regulating GPR56 trafficking dynamics and agonist activities are not yet clear. Methods Here, we introduced SNAPf-tag into the N-terminal segment of GPR56 to monitor GPR56 cellular activity in situ. Confocal and super-resolution microscopy were used to investigate the trafficking pattern of GPR56 in native MIN6 β-cells and in MIN6 β-cells where GPR56 had been deleted by CRISPR-Cas9 gene editing. Insulin secretion, changes in intracellular calcium, and β-cell apoptosis were determined by radioimmunoassay, single-cell calcium microfluorimetry, and measuring caspase 3/7 activities, respectively, in MIN6 β-cells and human islets. Results SNAP-tag labelling indicated that GPR56 predominantly underwent constitutive internalisation in the absence of an exogenous agonist, unlike GLP-1R. Collagen III further stimulated GPR56 internalisation, whereas P7 was without significant effect. The overexpression of GPR56 in MIN6 β-cells did not affect insulin secretion. However, it was associated with reduced β-cell apoptosis, while the deletion of GPR56 made MIN6 β-cells more susceptible to cytokine-induced apoptosis. P7 induced a rapid increase in the intracellular calcium in MIN6 β-cells (in a GPR56-dependent manner) and human islets, and it also caused a sustained and reversible increase in insulin secretion from human islets. Collagen III protected human islets from cytokine-induced apoptosis, while P7 was without significant effect. Conclusions These data indicate that GPR56 exhibits both agonist-dependent and -independent trafficking in β-cells and suggest that while GPR56 undergoes constitutive signalling, it can also respond to its ligands when required. We have also identified that constitutive and agonist-dependent GPR56 activation is coupled to protect β-cells against apoptosis, offering a potential therapeutic target to maintain β-cell mass in type 2 diabetes. GPR56 predominantly underwent constitutive internalisation in β-cells in the absence of exogenous agonist. The GPR56 agonists, collagen III and P7, showed differential effects on GPR56 trafficking and islet functions. Constitutive and agonist-dependent GPR56 activation is coupled to protection of β-cells against apoptosis.
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Affiliation(s)
- Oladapo E Olaniru
- Department of Diabetes, School of Life Course Sciences, King's College London, Guy's Campus, London SE1 1UL, UK.
| | - Jordan Cheng
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering & Imaging Sciences, 4th floor Lambeth Wing, St Thomas' Hospital, London, SE1 7EH, UK
| | - Julia Ast
- Institute of Metabolism and Systems Research (IMSR), Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Anastasia Arvaniti
- Institute of Metabolism and Systems Research (IMSR), Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Patricio Atanes
- Department of Diabetes, School of Life Course Sciences, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Guo C Huang
- Department of Diabetes, School of Life Course Sciences, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Aileen J F King
- Department of Diabetes, School of Life Course Sciences, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Peter M Jones
- Department of Diabetes, School of Life Course Sciences, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Johannes Broichhagen
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Shanta J Persaud
- Department of Diabetes, School of Life Course Sciences, King's College London, Guy's Campus, London SE1 1UL, UK.
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Sayers SR, Beavil RL, Fine NHF, Huang GC, Choudhary P, Pacholarz KJ, Barran PE, Butterworth S, Mills CE, Cruickshank JK, Silvestre MP, Poppitt SD, McGill AT, Lavery GG, Hodson DJ, Caton PW. Structure-functional changes in eNAMPT at high concentrations mediate mouse and human beta cell dysfunction in type 2 diabetes. Diabetologia 2020; 63:313-323. [PMID: 31732790 PMCID: PMC6946736 DOI: 10.1007/s00125-019-05029-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 09/11/2019] [Indexed: 02/26/2023]
Abstract
AIMS/HYPOTHESIS Progressive decline in functional beta cell mass is central to the development of type 2 diabetes. Elevated serum levels of extracellular nicotinamide phosphoribosyltransferase (eNAMPT) are associated with beta cell failure in type 2 diabetes and eNAMPT immuno-neutralisation improves glucose tolerance in mouse models of diabetes. Despite this, the effects of eNAMPT on functional beta cell mass are poorly elucidated, with some studies having separately reported beta cell-protective effects of eNAMPT. eNAMPT exists in structurally and functionally distinct monomeric and dimeric forms. Dimerisation is essential for the NAD-biosynthetic capacity of NAMPT. Monomeric eNAMPT does not possess NAD-biosynthetic capacity and may exert distinct NAD-independent effects. This study aimed to fully characterise the structure-functional effects of eNAMPT on pancreatic beta cell functional mass and to relate these to beta cell failure in type 2 diabetes. METHODS CD-1 mice and serum from obese humans who were without diabetes, with impaired fasting glucose (IFG) or with type 2 diabetes (from the Body Fat, Surgery and Hormone [BodyFatS&H] study) or with or at risk of developing type 2 diabetes (from the VaSera trial) were used in this study. We generated recombinant wild-type and monomeric eNAMPT to explore the effects of eNAMPT on functional beta cell mass in isolated mouse and human islets. Beta cell function was determined by static and dynamic insulin secretion and intracellular calcium microfluorimetry. NAD-biosynthetic capacity of eNAMPT was assessed by colorimetric and fluorescent assays and by native mass spectrometry. Islet cell number was determined by immunohistochemical staining for insulin, glucagon and somatostatin, with islet apoptosis determined by caspase 3/7 activity. Markers of inflammation and beta cell identity were determined by quantitative reverse transcription PCR. Total, monomeric and dimeric eNAMPT and nicotinamide mononucleotide (NMN) were evaluated by ELISA, western blot and fluorometric assay using serum from non-diabetic, glucose intolerant and type 2 diabetic individuals. RESULTS eNAMPT exerts bimodal and concentration- and structure-functional-dependent effects on beta cell functional mass. At low physiological concentrations (~1 ng/ml), as seen in serum from humans without diabetes, eNAMPT enhances beta cell function through NAD-dependent mechanisms, consistent with eNAMPT being present as a dimer. However, as eNAMPT concentrations rise to ~5 ng/ml, as in type 2 diabetes, eNAMPT begins to adopt a monomeric form and mediates beta cell dysfunction, reduced beta cell identity and number, increased alpha cell number and increased apoptosis, through NAD-independent proinflammatory mechanisms. CONCLUSIONS/INTERPRETATION We have characterised a novel mechanism of beta cell dysfunction in type 2 diabetes. At low physiological levels, eNAMPT exists in dimer form and maintains beta cell function and identity through NAD-dependent mechanisms. However, as eNAMPT levels rise, as in type 2 diabetes, structure-functional changes occur resulting in marked elevation of monomeric eNAMPT, which induces a diabetic phenotype in pancreatic islets. Strategies to selectively target monomeric eNAMPT could represent promising therapeutic strategies for the treatment of type 2 diabetes.
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Affiliation(s)
- Sophie R Sayers
- Diabetes Research Group, Department of Diabetes, School of Life Course Sciences, King's College London, Hodgkin Building, Guy's Campus, London, SE1 1UL, UK
| | - Rebecca L Beavil
- Protein Production Facility, Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Nicholas H F Fine
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Guo C Huang
- Diabetes Research Group, Department of Diabetes, School of Life Course Sciences, King's College London, Hodgkin Building, Guy's Campus, London, SE1 1UL, UK
| | - Pratik Choudhary
- Diabetes Research Group, Department of Diabetes, School of Life Course Sciences, King's College London, Hodgkin Building, Guy's Campus, London, SE1 1UL, UK
| | - Kamila J Pacholarz
- Michael Barber Centre for Collaborative Mass Spectrometry, School of Chemistry, Manchester Institute of Biotechnology, Manchester, UK
| | - Perdita E Barran
- Michael Barber Centre for Collaborative Mass Spectrometry, School of Chemistry, Manchester Institute of Biotechnology, Manchester, UK
| | - Sam Butterworth
- Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Charlotte E Mills
- Department of Nutritional Sciences, School of Life Course Sciences, King's College London, London, UK
- Nutrition Research Group, University of Reading, Reading, UK
| | - J Kennedy Cruickshank
- Department of Nutritional Sciences, School of Life Course Sciences, King's College London, London, UK
| | - Marta P Silvestre
- Human Nutrition Unit, School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Sally D Poppitt
- Human Nutrition Unit, School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Anne-Thea McGill
- Human Nutrition Unit, School of Biological Sciences, University of Auckland, Auckland, New Zealand
- School of Health & Human Sciences, Southern Cross University, Lismore, NSW, Australia
| | - Gareth G Lavery
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Paul W Caton
- Diabetes Research Group, Department of Diabetes, School of Life Course Sciences, King's College London, Hodgkin Building, Guy's Campus, London, SE1 1UL, UK.
- Department of Nutritional Sciences, School of Life Course Sciences, King's College London, London, UK.
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Pingitore A, Gonzalez-Abuin N, Ruz-Maldonado I, Huang GC, Frost G, Persaud SJ. Short chain fatty acids stimulate insulin secretion and reduce apoptosis in mouse and human islets in vitro: Role of free fatty acid receptor 2. Diabetes Obes Metab 2019; 21:330-339. [PMID: 30203438 DOI: 10.1111/dom.13529] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/29/2018] [Accepted: 09/05/2018] [Indexed: 12/28/2022]
Abstract
AIMS To evaluate the role of free fatty acid receptor 2 (FFAR2)/G-protein coupled receptor 43 in mediating the effects of the short chain fatty acids (SCFAs) sodium acetate (SA) and sodium propionate (SP) on islet function in vitro, and to identify the intracellular signalling pathways used in SCFA-induced potentiation of glucose-induced insulin secretion. MATERIALS AND METHODS Islets of Langerhans were isolated from wild-type and FFAR2-/- mice and from human donors without diabetes. The effects of SA and SP on dynamic insulin secretion from perifused islets were quantified by radioimmunoassay, signalling downstream of SCFAs was profiled by single-cell calcium microfluorimetry, and measurement of cAMP was performed using a fluorescence assay. Islet apoptosis was induced by exposure to cytokines or sodium palmitate, and the effects of SA and SP in regulating islet apoptosis were assessed by quantification of caspase 3/7 activities. RESULTS Deletion of FFAR2 did not affect islet morphology or insulin content. SA and SP reversibly potentiated insulin secretion from mouse islets in a FFAR2-dependent manner. SCFA-induced potentiation of insulin secretion was coupled to Gq activation of phospholipase C and protein kinase C, with no evidence of Gi-mediated signalling. SA and SP protected human and mouse islets from apoptosis, and these pro-survival properties were dependent on islet expression of FFAR2. CONCLUSION Our results indicate that FFAR2 directly mediates both the stimulatory effects of SA and SP on insulin secretion and their protection against islet apoptosis. We have also shown that SCFA coupling in islets occurs via Gq-coupled intracellular signalling.
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Affiliation(s)
- Attilio Pingitore
- Department of Diabetes, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Noemi Gonzalez-Abuin
- Division of Human Nutrition, Faculty of Medicine, Imperial College London, London, UK
| | - Inmaculada Ruz-Maldonado
- Department of Diabetes, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Guo C Huang
- Department of Diabetes, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Gary Frost
- Division of Human Nutrition, Faculty of Medicine, Imperial College London, London, UK
| | - Shanta J Persaud
- Department of Diabetes, Faculty of Life Sciences and Medicine, King's College London, London, UK
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Pingitore A, Chambers ES, Hill T, Maldonado IR, Liu B, Bewick G, Morrison DJ, Preston T, Wallis GA, Tedford C, Castañera González R, Huang GC, Choudhary P, Frost G, Persaud SJ. The diet-derived short chain fatty acid propionate improves beta-cell function in humans and stimulates insulin secretion from human islets in vitro. Diabetes Obes Metab 2017; 19:257-265. [PMID: 27761989 DOI: 10.1111/dom.12811] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 10/13/2016] [Accepted: 10/14/2016] [Indexed: 12/18/2022]
Abstract
AIMS Diet-derived short chain fatty acids (SCFAs) improve glucose homeostasis in vivo, but the role of individual SCFAs and their mechanisms of action have not been defined. This study evaluated the effects of increasing colonic delivery of the SCFA propionate on β-cell function in humans and the direct effects of propionate on isolated human islets in vitro. MATERIALS AND METHODS For 24 weeks human subjects ingested an inulin-propionate ester that delivers propionate to the colon. Acute insulin, GLP-1 and non-esterified fatty acid (NEFA) levels were quantified pre- and post-supplementation in response to a mixed meal test. Expression of the SCFA receptor FFAR2 in human islets was determined by western blotting and immunohistochemistry. Dynamic insulin secretion from perifused human islets was quantified by radioimmunoassay and islet apoptosis was determined by quantification of caspase 3/7 activities. RESULTS Colonic propionate delivery in vivo was associated with improved β-cell function with increased insulin secretion that was independent of changes in GLP-1 levels. Human islet β-cells expressed FFAR2 and propionate potentiated dynamic glucose-stimulated insulin secretion in vitro, an effect that was dependent on signalling via protein kinase C. Propionate also protected human islets from apoptosis induced by the NEFA sodium palmitate and inflammatory cytokines. CONCLUSIONS Our results indicate that propionate has beneficial effects on β-cell function in vivo, and in vitro analyses demonstrated that it has direct effects to potentiate glucose-stimulated insulin release and maintain β-cell mass through inhibition of apoptosis. These observations support ingestion of propiogenic dietary fibres to maintain healthy glucose homeostasis.
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Affiliation(s)
- Attilio Pingitore
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
| | - Edward S Chambers
- Faculty of Medicine, Nutrition and Dietetic Research Group, Imperial College London, London, UK
| | - Thomas Hill
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
| | - Inmaculada Ruz Maldonado
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
| | - Bo Liu
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
| | - Gavin Bewick
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
| | - Douglas J Morrison
- Stable Isotope Biochemistry Laboratory, Scottish Universities Environmental Research Centre, University of Glasgow, Glasgow, UK
| | - Tom Preston
- Stable Isotope Biochemistry Laboratory, Scottish Universities Environmental Research Centre, University of Glasgow, Glasgow, UK
| | - Gareth A Wallis
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Catriona Tedford
- School of Science, University of the West of Scotland, Hamilton, UK
| | - Ramón Castañera González
- Department of General Surgery, Rio Carrión Hospital, University Hospital Complex of Palencia, Palencia, Spain
| | - Guo C Huang
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
| | - Pratik Choudhary
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
| | - Gary Frost
- Faculty of Medicine, Nutrition and Dietetic Research Group, Imperial College London, London, UK
| | - Shanta J Persaud
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
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Liu B, Song S, Ruz-Maldonado I, Pingitore A, Huang GC, Baker D, Jones PM, Persaud SJ. GPR55-dependent stimulation of insulin secretion from isolated mouse and human islets of Langerhans. Diabetes Obes Metab 2016; 18:1263-1273. [PMID: 27561953 DOI: 10.1111/dom.12780] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Revised: 08/10/2016] [Accepted: 08/22/2016] [Indexed: 01/15/2023]
Abstract
AIMS The novel cannabinoid receptor GPR55 is expressed by rodent islets and it has been implicated in β-cell function in response to a range of ligands. This study evaluated the effects of GPR55 ligands on intracellular calcium ([Ca2+ ]i ) levels and insulin secretion from islets isolated from GPR55 knockout (GPR55 -/- ) mice, age-matched wildtype (WT) mice and human pancreas. MATERIALS AND METHODS GPR55 expression was determined by Western blotting and fluorescent immunohistochemistry. Changes in [Ca2+ ]i were measured by Fura-2 microfluorimetry. Dynamic insulin secretion was quantified by radioimmunoassay following perifusion of isolated islets. RhoA activity was monitored using a Rho binding domain pull down assay. RESULTS Western blotting indicated that MIN6 β-cells, mouse and human islets express GPR55 and its localization on human β-cells was demonstrated by fluorescent immunohistochemistry. The pharmacological GPR55 agonist O-1602 (10 μM) significantly stimulated [Ca2+ ]i and insulin secretion from WT mouse islets and these stimulatory effects were abolished in islets isolated from GPR55 -/- mice. In contrast, while the putative endogenous GPR55 agonist lysophosphatidylinositol (LPI, 5 µM) and the GPR55 antagonist cannabidiol (CBD, 1 µM) also elevated [Ca2+ ]i and insulin secretion, these effects were sustained in islets from GPR55 -/- mice. Stimulatory effects of O-1602 on [Ca2+ ]i and insulin secretion were also observed in experiments using human islets, but O-1602 did not activate RhoA in MIN6 β-cells. CONCLUSIONS Our results therefore suggest that GPR55 plays an important role in the regulation of mouse and human islet physiology, but LPI and CBD exert stimulatory effects on islet function by a GPR55-independent pathway(s).
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Affiliation(s)
- Bo Liu
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
| | - Shuang Song
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
| | - Inmaculada Ruz-Maldonado
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
| | - Attilio Pingitore
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
| | - Guo C Huang
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
| | - David Baker
- Centre for Neuroscience and Trauma, Barts and The London School of Medicine and Dentistry, London, UK
| | - Peter M Jones
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
| | - Shanta J Persaud
- Division of Diabetes and Nutritional Sciences, Diabetes Research Group, King's College London, London, UK
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Zhang W, Wu Y, Gong L, Zhu HL, Huang GC, Zhou GQ, Wu KF, Liu DS. [Therapeutic effect of IGF-1R-targeting inhibitor (TAE226) on malignant pleural effusion in nude mice]. Zhonghua Zhong Liu Za Zhi 2016; 38:565-71. [PMID: 27531475 DOI: 10.3760/cma.j.issn.0253-3766.2016.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE To study the therapeutic effect of IGF-1R inhibitor TAE226 on malignant pleural effusion (MPE) in nude mice. METHODS Human lung carcinoma A549 cells were injected into the pleural cavity of nude mice to establish MPE model. The mice were randomly divided into model group and treatment group, and were orally administered with distilled water and TAE226 (20 mg/kg) in the same volume, respectively. The volume of pleural effusion and tumor weight of the two groups were observed. HE staining was used to reveal the histological changes and enzyme-linked immunosorbent assay (ELISA) was used to detect the IGF-1R protein expression. IGF-1R mRNA level in the tumor tissue was determined by RT-PCR. Microvessel density (MVD) and cell proliferation index (PI) were assessed by immunohistochemical analysis. The protein expression levels of IGF-1R, p-IGF-1R, PI3K and p-PI3K in the tumor tissue were determined by Western blotting. RESULTS The volumes of pleural effusion were (241.4±89.7) μl and (121.7±78.8) μl in the model and treatment groups, respectively (P<0.05). The tumor weight of treatment group was (316.7±186.3) mg, significantly lower than that of the model group (671.4±281.4) mg (P<0.05). RT-PCR analysis showed that IGF-1R mRNA level was 0.914±0.029 in the treatment group, significantly lower than that of the model group (1.152±0.037, P<0.01). The ELISA data revealed that IGF-1R protein expression level of the model group was significantly higher than that of the treatment group [(41.0±4.7) μg/L vs. (24.0±3.1) μg/L, P<0.01]. Immunohistochemical analysis showed that there were significant differences between MVD and PI in the model and treatment groups [MVD, 34.75±3.49 vs. 22.25±3.63; PI, (75.25±7.15)% vs. (45.75±5.12)%; P<0.01 for both). Western blot data showed that IGF-1R and PI3K protein expression levels were not significantly different between the model and treatment groups (1.03±0.33 vs. 0.98±0.37 and 1.05±0.28 vs. 0.98±0.19), respectively (P>0.05), but p-IGF-1R and p-PI3K protein expression levels had significant differences between the two groups (1.08±0.10 vs. 0.51±0.08 and 1.12±0.09 vs. 0.86±0.09), respectively (P<0.01 for both). CONCLUSIONS The IGF-1R inhibitor can effectively inhibit the formation of malignant pleural effusion. Its mechanism may be related to the suppression of tumor cell proliferation, invasion and angiogenesis through inhibition of PI3K signaling. TAE226 treatment may be a potential therapeutic regimen of treating malignant pleural effusion.
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Affiliation(s)
- W Zhang
- Department of Respiratory Medicine, the First People's Hospital of Zunyi, Zunyi 563000, China
| | - Y Wu
- Department of Respiratory Medicine, the First People's Hospital of Zunyi, Zunyi 563000, China
| | - L Gong
- Department of Respiratory Medicine, the First People's Hospital of Zunyi, Zunyi 563000, China
| | - H L Zhu
- Department of Respiratory Medicine, the First People's Hospital of Zunyi, Zunyi 563000, China
| | - G C Huang
- Department of Respiratory Medicine, the First People's Hospital of Zunyi, Zunyi 563000, China
| | - G Q Zhou
- Department of Respiratory Medicine, the First People's Hospital of Zunyi, Zunyi 563000, China
| | - K F Wu
- Clinical Laboratory, the First People's Hospital of Zunyi, Zunyi 563000, China
| | - D S Liu
- Department of Respiratory Medicine, the First People's Hospital of Zunyi, Zunyi 563000, China
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Vilches-Flores A, Franklin Z, Hauge-Evans AC, Liu B, Huang GC, Choudhary P, Jones PM, Persaud SJ. Prolonged activation of human islet cannabinoid receptors in vitro induces adaptation but not dysfunction. BBA Clin 2016; 5:143-50. [PMID: 27114924 PMCID: PMC4832123 DOI: 10.1016/j.bbacli.2016.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 03/26/2016] [Accepted: 03/29/2016] [Indexed: 11/17/2022]
Abstract
BACKGROUND Although in vivo studies have implicated endocannabinoids in metabolic dysfunction, little is known about direct, chronic activation of the endocannabinoid system (ECS) in human islets. Therefore, this study investigated the effects of prolonged exposure to cannabinoid agonists on human islet gene expression and function. METHODS Human islets were maintained for 2 and 5 days in the absence or presence of CB1r (ACEA) or CB2r (JWH015) agonists. Gene expression was quantified by RT-PCR, hormone levels by radioimmunoassay and apoptosis by caspase activities. RESULTS Human islets express an ECS, with mRNAs encoding the biosynthetic and degrading enzymes NAPE-PLD, FAAH and MAGL being considerably more abundant than DAGLα, an enzyme involved in 2-AG synthesis, or CB1 and CB2 receptor mRNAs. Prolonged activation of CB1r and CB2r altered expression of mRNAs encoding ECS components, but did not have major effects on islet hormone secretion. JWH015 enhanced insulin and glucagon content at 2 days, but had no effect after 5 days. Treatment with ACEA or JWH015 for up to 5 days did not have marked effects on islet viability, as assessed by morphology and caspase activities. CONCLUSIONS Maintenance of human islets for up to 5 days in the presence of CB1 and CB2 receptor agonists causes modifications in ECS element gene expression, but does not have any major impact on islet function or viability. GENERAL SIGNIFICANCE These data suggest that the metabolic dysfunction associated with over-activation of the ECS in obesity and diabetes in humans is unlikely to be secondary to impaired islet function.
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Key Words
- 2-AG, 2-arachidonoyl glycerol
- ACEA, N-(2-Chloroethyl)-5Z,8Z,11Z,14Z-eiscosatetraenamide
- AEA, anandamide
- Apoptosis
- CB1r, cannabinoid receptor type 1
- CB2r, cannabinoid receptor type 2
- DAGL, diacylglycerol lipase
- ECS, endocannabinoid system
- Endocannabinoid system
- FAAH, fatty acid amide hydrolase
- Gene expression
- Glucagon
- Human islets
- Insulin
- JWH015, (2-methyl-1propyl-1H-indol-3-yl)-1-napthalenylmethanone
- MAGL, monoacylglycerol lipase
- NAPE-PLD, N-acyl-phosphatidyl ethanolamide-hydrolysing phospholipase D
- PPG, preproglucagon
- PPI, preproinsulin
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Affiliation(s)
- Alonso Vilches-Flores
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, King's College London, UK
- Universidad Nacional Autonoma de Mexico, FES Iztacala, Mexico
| | - Zara Franklin
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, King's College London, UK
| | - Astrid C. Hauge-Evans
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, King's College London, UK
- Department of Life Sciences, University of Roehampton, London, UK
| | - Bo Liu
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, King's College London, UK
| | - Guo C. Huang
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, King's College London, UK
| | - Pratik Choudhary
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, King's College London, UK
| | - Peter M. Jones
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, King's College London, UK
| | - Shanta J. Persaud
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, King's College London, UK
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8
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Knight RR, Dolton G, Kronenberg-Versteeg D, Eichmann M, Zhao M, Huang GC, Beck K, Cole DK, Sewell AK, Skowera A, Peakman M. A distinct immunogenic region of glutamic acid decarboxylase 65 is naturally processed and presented by human islet cells to cytotoxic CD8 T cells. Clin Exp Immunol 2015; 179:100-7. [PMID: 25112375 DOI: 10.1111/cei.12436] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2014] [Indexed: 12/20/2022] Open
Abstract
CD8 T cells specific for islet autoantigens are major effectors of β cell damage in type 1 diabetes, and measurement of their number and functional characteristics in blood represent potentially important disease biomarkers. CD8 T cell reactivity against glutamic acid decarboxylase 65 (GAD65) in HLA-A*0201 subjects has been reported to focus on an immunogenic region 114-123 (VMNILLQYVV), with studies demonstrating both 114-123 and 114-122 epitopes being targeted. However, the fine specificity of this response is unclear and the key question as to which epitope(s) β cells naturally process and present and, therefore, the pathogenic potential of CD8 T cells with different specificities within this region has not been addressed. We generated human leucocyte antigen (HLA)-A*0201-restricted CD8 T cell clones recognizing either 114-122 alone or both 114-122 and 114-123. Both clone types show potent and comparable effector functions (cytokine and chemokine secretion) and killing of indicator target cells externally pulsed with cognate peptide. However, only clones recognizing 114-123 kill target cells transfected with HLA-A*0201 and GAD2 and HLA-A*0201(+) human islet cells. We conclude that the endogenous pathway of antigen processing by HLA-A*0201-expressing cells generates GAD65114-123 as the predominant epitope in this region. These studies highlight the importance of understanding β cell epitope presentation in the design of immune monitoring for potentially pathogenic CD8 T cells.
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Affiliation(s)
- R R Knight
- Department of Immunobiology, King's College London, London, UK
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9
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Zhao M, Choudhary P, Srinivasan P, Tang H, Heaton N, Fung M, Barthel A, Bornstein SR, Amiel SA, Huang GC. Modification of human islet preparation: an effective approach to improve graft outcome after islet transplantation? Horm Metab Res 2015; 47:72-7. [PMID: 25372780 DOI: 10.1055/s-0034-1390489] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Revascularisation of transplanted islets is an essential prerequisite for graft survival and function. However, current islet isolation procedures deprive the islets of endothelial tubulets. This may have a detrimental effect on the revascularisation process of islets following transplantation. We hypothesise that modification of the isolation procedure that preserves islet endothelial vessels may improve the islet revascularisation process following transplantation. Here, we present a modified islet isolation method by which a substantial amount of endothelial cells still attached to the islets could be preserved. The islets with preserved endothelial cells isolated by this method were revascularised within 3 days, not observed in islets isolated by standard methods. Further, we observed that grafts of islets isolated by standard methods had more patches of dead tissue than islet grafts obtained by the modified method, indicating that attached endothelial cells may play an important role in the islet revascularisation process and potentially help to improve the transplantation outcome.
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Affiliation(s)
- M Zhao
- Department of Diabetes and Endocrinology, Division of Diabetes and Nutrients King's College London, London, UK
| | - P Choudhary
- Department of Diabetes and Endocrinology, Division of Diabetes and Nutrients King's College London, London, UK
| | - P Srinivasan
- Institute of Liver Studies, King's College Hospital, London, UK
| | - H Tang
- Department of Diabetes and Endocrinology, Division of Diabetes and Nutrients King's College London, London, UK
| | - N Heaton
- Institute of Liver Studies, King's College Hospital, London, UK
| | - M Fung
- Department of Diabetes and Endocrinology, Division of Diabetes and Nutrients King's College London, London, UK
| | - A Barthel
- Department of Medicine III, Dresden, Germany
| | - S R Bornstein
- Department of Diabetes and Endocrinology, Division of Diabetes and Nutrients King's College London, London, UK
| | - S A Amiel
- Department of Diabetes and Endocrinology, Division of Diabetes and Nutrients King's College London, London, UK
| | - G C Huang
- Department of Diabetes and Endocrinology, Division of Diabetes and Nutrients King's College London, London, UK
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10
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Brooks AM, Walker N, Aldibbiat A, Hughes S, Jones G, de Havilland J, Choudhary P, Huang GC, Parrott N, McGowan NWA, Casey J, Mumford L, Barker P, Burling K, Hovorka R, Walker M, Smith RM, Forbes S, Rutter MK, Amiel S, Rosenthal MJ, Johnson P, Shaw JAM. Attainment of metabolic goals in the integrated UK islet transplant program with locally isolated and transported preparations. Am J Transplant 2013; 13:3236-43. [PMID: 24119216 DOI: 10.1111/ajt.12469] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 08/02/2013] [Accepted: 08/10/2013] [Indexed: 01/25/2023]
Abstract
The objective was to determine whether metabolic goals have been achieved with locally isolated and transported preparations over the first 3 years of the UK's nationally funded integrated islet transplant program. Twenty islet recipients with C-peptide negative type 1 diabetes and recurrent severe hypoglycemia consented to the study, including standardized meal tolerance tests. Participants received a total of 35 infusions (seven recipients: single graft; 11 recipients: two grafts: two recipients: three grafts). Graft function was maintained in 80% at [median (interquartile range)] 24 (13.5-36) months postfirst transplant. Severe hypoglycemia was reduced from 20 (7-50) episodes/patient-year pretransplant to 0.3 (0-1.6) episodes/patient-year posttransplant (p < 0.001). Resolution of impaired hypoglycemia awareness was confirmed [pretransplant: Gold score 6 (5-7); 24 (13.5-36) months: 3 (1.5-4.5); p < 0.03]. Target HbA1c of <7.0% was attained/maintained in 70% of recipients [pretransplant: 8.0 (7.0-9.6)%; 24 (13.5-36) months: 6.2 (5.7-8.4)%; p < 0.001], with 60% reduction in insulin dose [pretransplant: 0.51 (0.41-0.62) units/kg; 24 (13.5-36) months: 0.20 (0-0.37) units/kg; p < 0.001]. Metabolic outcomes were comparable 12 months posttransplant in those receiving transported versus only locally isolated islets [12 month stimulated C-peptide: transported 788 (114-1764) pmol/L (n = 9); locally isolated 407 (126-830) pmol/L (n = 11); p = 0.32]. Metabolic goals have been attained within the equitably available, fully integrated UK islet transplant program with both transported and locally isolated preparations.
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Affiliation(s)
- A M Brooks
- Institute of Cellular Medicine, Newcastle University, Newcastle, UK
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11
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Fairhall EA, Wallace K, White SA, Huang GC, Shaw JA, Wright SC, Charlton KA, Burt AD, Wright MC. Adult human exocrine pancreas differentiation to hepatocytes – potential source of a human hepatocyte progenitor for use in toxicology research. Toxicol Res (Camb) 2013. [DOI: 10.1039/c2tx20061a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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12
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Kronenberg D, Knight RR, Estorninho M, Ellis RJ, Kester MG, de Ru A, Eichmann M, Huang GC, Powrie J, Dayan CM, Skowera A, van Veelen PA, Peakman M. Circulating preproinsulin signal peptide-specific CD8 T cells restricted by the susceptibility molecule HLA-A24 are expanded at onset of type 1 diabetes and kill β-cells. Diabetes 2012; 61:1752-9. [PMID: 22522618 PMCID: PMC3379678 DOI: 10.2337/db11-1520] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Type 1 diabetes results from T cell-mediated β-cell destruction. The HLA-A*24 class I gene confers significant risk of disease and early onset. We tested the hypothesis that HLA-A24 molecules on islet cells present preproinsulin (PPI) peptide epitopes to CD8 cytotoxic T cells (CTLs). Surrogate β-cell lines secreting proinsulin and expressing HLA-A24 were generated and their peptide ligandome examined by mass spectrometry to discover naturally processed and HLA-A24-presented PPI epitopes. A novel PPI epitope was identified and used to generate HLA-A24 tetramers and examine the frequency of PPI-specific T cells in new-onset HLA-A*24(+) patients and control subjects. We identified a novel naturally processed and HLA-A24-presented PPI signal peptide epitope (PPI(3-11); LWMRLLPLL). HLA-A24 tetramer analysis reveals a significant expansion of PPI(3-11)-specific CD8 T cells in the blood of HLA-A*24(+) recent-onset patients compared with HLA-matched control subjects. Moreover, a patient-derived PPI(3-11)-specific CD8 T-cell clone shows a proinflammatory phenotype and kills surrogate β-cells and human HLA-A*24(+) islet cells in vitro. These results indicate that the type 1 diabetes susceptibility molecule HLA-A24 presents a naturally processed PPI signal peptide epitope. PPI-specific, HLA-A24-restricted CD8 T cells are expanded in patients with recent-onset disease. Human islet cells process and present PPI(3-11), rendering themselves targets for CTL-mediated killing.
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Affiliation(s)
- Deborah Kronenberg
- National Institute for Health Research Comprehensive Biomedical Research Centre at Guy’s and St. Thomas’ National Health Service Foundation Trust and King’s College London, London, U.K
- Department of Immunobiology, King’s College London, London, U.K
| | - Robin R. Knight
- Department of Immunobiology, King’s College London, London, U.K
| | | | | | - Michel G. Kester
- Department of Hematology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Arnoud de Ru
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Centre, Leiden, the Netherlands
| | - Martin Eichmann
- Department of Immunobiology, King’s College London, London, U.K
| | - Guo C. Huang
- Division of Diabetes and Nutritional Science, King’s College London, London, U.K
| | - Jake Powrie
- National Institute for Health Research Comprehensive Biomedical Research Centre at Guy’s and St. Thomas’ National Health Service Foundation Trust and King’s College London, London, U.K
- Department of Diabetes and Endocrinology, Guy’s and St. Thomas’ Hospital National Health Service Foundation Trust, London, U.K
| | - Colin M. Dayan
- Department of Medicine, Cardiff University, Cardiff, Wales, U.K
| | - Ania Skowera
- National Institute for Health Research Comprehensive Biomedical Research Centre at Guy’s and St. Thomas’ National Health Service Foundation Trust and King’s College London, London, U.K
- Department of Immunobiology, King’s College London, London, U.K
| | - Peter A. van Veelen
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Centre, Leiden, the Netherlands
| | - Mark Peakman
- National Institute for Health Research Comprehensive Biomedical Research Centre at Guy’s and St. Thomas’ National Health Service Foundation Trust and King’s College London, London, U.K
- Department of Immunobiology, King’s College London, London, U.K
- Corresponding author: Mark Peakman,
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13
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Li C, Bowe JE, Huang GC, Amiel SA, Jones PM, Persaud SJ. Cannabinoid receptor agonists and antagonists stimulate insulin secretion from isolated human islets of Langerhans. Diabetes Obes Metab 2011; 13:903-10. [PMID: 21564460 DOI: 10.1111/j.1463-1326.2011.01422.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS The role of cannabinoid receptors in human islets of Langerhans has not been investigated in any detail, so the current study examined CB1 and CB2 receptor expression by human islets and the effects of pharmacological cannabinoid receptor agonists and antagonists on insulin secretion. METHODS Human islets were isolated from pancreases retrieved from heart-beating organ donors. Messenger RNAs encoding human CB1 and CB2 receptors were amplified from human islet RNA by RT-PCR and receptor localization within islets was identified by immunohistochemistry. Dynamic insulin secretion from human islets perifused with buffers supplemented with CB1 and CB2 receptor agonists and antagonists was quantified by radioimmunoassay. RESULTS RT-PCR showed that both CB1 and CB2 receptors are expressed by human islets and immunohistochemistry indicated that receptor expression co-localized with insulin-expressing β-cells. Perifusion experiments using isolated human islets showed that insulin secretion was reversibly stimulated by both CB1 and CB2 receptor agonists, with CB1 receptor activation associated with increased basal secretion whereas CB2 receptors were coupled to initiation and potentiation of insulin secretion. Antagonists at CB1 (N-(Piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide) and CB2 (N-(1,3-Benzodioxol-5-ylmethyl)-1,2-dihydro-7-methoxy-2-oxo-8-(pentyloxy)-3-quinoline carboxamide) receptors failed to inhibit the stimulatory effects of the respective agonists and, unexpectedly, reversibly stimulated insulin secretion. CONCLUSIONS These data confirm the expression of CB1 and CB2 receptors by human islets and indicate that both receptor subtypes are coupled to the stimulation of insulin secretion. They also implicate involvement of CB1/2 receptor-independent pathways in the antagonist-induced stimulatory effects.
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MESH Headings
- Humans
- Immunohistochemistry
- Insulin/metabolism
- Insulin Secretion
- Islets of Langerhans/drug effects
- Islets of Langerhans/metabolism
- RNA, Messenger/genetics
- Radioimmunoassay
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/agonists
- Receptor, Cannabinoid, CB2/antagonists & inhibitors
- Receptor, Cannabinoid, CB2/genetics
- Receptor, Cannabinoid, CB2/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- C Li
- Diabetes Research Group, Division of Diabetes & Nutritional Sciences, King's College London, London, UK
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14
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Lozanoska-Ochser B, Klein NJ, Huang GC, Alvarez RA, Peakman M. Expression of CD86 on human islet endothelial cells facilitates T cell adhesion and migration. J Immunol 2009; 181:6109-16. [PMID: 18941200 DOI: 10.4049/jimmunol.181.9.6109] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Pancreatic islet endothelial cells (ECs) form the barrier across which autoreactive T cells transmigrate during the development of islet inflammation in type 1 diabetes. Little is known about the immune phenotype of islet ECs that might shape their molecular interaction with autoreactive T cells before and during the development of islet inflammation. In this study we examined the expression and functional significance of costimulatory molecules by human islet ECs. Freshly isolated human islet ECs constitutively expressed CD86 (B7-2) and ICOS ligand but not CD80 (B7-1) or CD40 costimulatory molecules. The functional activity of islet EC-expressed CD86 was examined by coculture of resting islet ECs with CD4 T cells stimulated by CD3 ligation alone. Marked T cell proliferation in the coculture was completely abrogated by mAb blockade of CD86, confirming that costimulatory properties are conferred on ECs by CD86 expression. In view of its location on the vasculature, we hypothesized a role for CD86 in T cell adhesion/transmigration. In keeping with this, adhesion/transmigration of activated (CD3 ligated) memory (CD45R0(+)) CD4 T cells across islet ECs was completely inhibited in the presence of CD86 blocking mAb. Identical results were obtained for T cell adhesion using either CTLA-4 blocking mAb or CTLA-4Ig (abatacept), indicating CTLA-4 as the T cell ligand for these CD86-mediated effects. These data suggest a novel role for CD86 expression on the microvasculature, whereby ligation of CTLA-4 on CD4 T cells by CD86 on islet ECs is key to the adhesion of recently activated T cells.
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15
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Aldibbiat A, Marriott CE, Scougall KT, Campbell SC, Huang GC, Macfarlane WM, Shaw JAM. Inability to process and store proinsulin in transdifferentiated pancreatic acinar cells lacking the regulated secretory pathway. J Endocrinol 2008; 196:33-43. [PMID: 18180315 DOI: 10.1677/joe-07-0397] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Generation of new beta-cells from the adult pancreas or the embryonic stem cells is being pursued by research groups worldwide. Success will be dependent on confirmation of true beta-cell phenotype evidenced by capacity to process and store proinsulin. The aim of these studies was to robustly determine endocrine characteristics of the AR42J rat pancreatic acinar cell line before and after in vitro transdifferentiation. beta-cell phenotypic marker expression was characterised by RT-PCR, immunostaining, western blotting, ELISA and in human preproinsulin transgene over-expression studies in wild-type AR42J cells and after culture on Matrigel basement membrane matrix with and without growth/differentiation factor supplementation. Pancreatic duodenal homeobox 1 (PDX1), forkhead box transcription factor a2 (Foxa2), glucokinase, pancreatic polypeptide and low-level insulin gene transcription in wild-type AR42J cells were confirmed by RT-PCR. Culture on Matrigel-coated plates and supplementation of medium with glucagon-like peptide 1 induced expression of the beta-cell Glut 2 with maintained expression of insulin and PDX1. Increased biosynthesis and secretion of proinsulin were confirmed by immunocytochemical staining and sensitive ELISA. Absence of the regulated secretory pathway was demonstrated by undetectable prohormone convertase expression. In addition, inability to process and store endogenous proinsulin or human proinsulin translated from a constitutively over-expressed preproinsulin transgene was confirmed. The importance of robust phenotypic characterisation at the protein level in attempted beta-cell transdifferentiation studies has been confirmed. Rodent and human sensitive/specific differential proinsulin/insulin ELISA in combination with human preproinsulin over-expression enables detailed elucidatation of core endocrine functions of proinsulin processing and storage in putative new beta-cells.
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Affiliation(s)
- A Aldibbiat
- Diabetes Research Group, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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16
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Zhao M, Muiesan P, Amiel SA, Srinivasan P, Asare-Anane H, Fairbanks L, Persaud S, Jones P, Jones J, Ashraf S, Littlejohn W, Rela M, Heaton N, Huang GC. Human islets derived from donors after cardiac death are fully biofunctional. Am J Transplant 2007; 7:2318-25. [PMID: 17845565 DOI: 10.1111/j.1600-6143.2007.01937.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Islets from brain-dead donors (BDDs) are being used in the treatment of Type 1 diabetes. However, both donor numbers and islet survival are limited. We explored the clinical potential for islets from non-heart-beating donors (NHBDs), who have lower circulating cytokines, by comparing islets from 10 NHBDs against 12 identically-isolated islets from BDDs over the same time period. The quantity and quality of islets from NHBDs was good. NHBD yielded approximately 12.6% more islets than those of BDDs (505,000 +/- 84,230 vs. 400,970 +/- 172,430 islet equivalent number [IEQ]/pancreas, p = 0.01) with comparable viability. ATP and GTP contents were lower (6.026 +/- 3.076 vs. 18.105 +/- 7.8 nM/mg protein, p = 0.01 and 1.52 +/- 0.87 vs. 3.378 +/- 0.83 nM/mg protein, p = 0.04) and correlated negatively to warm ischemia time (R(2)= 0.8022 and R(2)= 0.7996, respectively). Islets from NHBDs took longer to control hyperglycemia in diabetic mice, but were equally able to sustain euglycemia. With a warm ischemia time (WIT) of <or=25 min, islets from NHBDs are at least as competent as islets from BDDs and should be suitable for clinical use.
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Affiliation(s)
- M Zhao
- Diabetes Research Group, King's College London School of Medicine, London, UK
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17
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Muller D, Huang GC, Amiel S, Jones PM, Persaud SJ. Gene expression heterogeneity in human islet endocrine cells in vitro: the insulin signalling cascade. Diabetologia 2007; 50:1239-42. [PMID: 17440705 DOI: 10.1007/s00125-007-0671-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Accepted: 03/05/2007] [Indexed: 11/24/2022]
Abstract
AIMS/HYPOTHESIS Insulin secretion is a highly regulated mechanism involving a complex insulin-dependent network of communication between alpha, beta and delta cells. However, whereas the role of insulin in beta cells has been well documented, very little is known about its role in alpha and delta cells. Having recently demonstrated heterogeneity of insulin receptor (INSR) isoform expression in these three endocrine cell types, our current study aimed to characterise the expression pattern of the multiple isoforms involved in the insulin signal transduction cascade in human alpha, beta and delta cells in vitro. MATERIALS AND METHODS cDNA samples prepared from single human islet cells were subjected to nested PCRs. RESULTS Of 706 cells analysed, 15% were alpha cells, 28% beta cells, 8% delta cells and 46% non-endocrine cells. Profiling of expression of the insulin signalling cascade elements showed a heterogeneity between islet cell types, although at least one member of each protein family was expressed in the three populations of endocrine cells. Thus, the mRNAs coding for INSR-B, phosphoinositide-dependent protein kinase-1 and the human homologue of v-akt murine thymoma viral oncogene homologue 1 (AKT1) could not be detected in alpha cells, but were expressed by beta and delta cells. In addition, while the insulin receptor substrates IRS1 and IRS2, phosphoinositide-3-kinase, catalytic, beta polypeptide (PIK3CB) and AKT2 were expressed with relatively low frequencies in alpha and delta cells (<17% for IRS1, IRS2, PIK3CB; <25% for AKT2), their frequencies of expression in beta cells were 50, 33, 33 and 100%, respectively. CONCLUSIONS/INTERPRETATION Our results suggest that insulin signalling cascade elements in human alpha, beta and delta cells have distinct expression patterns.
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Affiliation(s)
- D Muller
- Beta Cell Development & Function Group, Division of Reproduction & Endocrinology, School of Biomedical & Health Sciences, King's College London, London, UK.
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18
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Zanone MM, Favaro E, Ferioli E, Huang GC, Klein NJ, Perin PC, Peakman M, Conaldi PG, Camussi G. Human pancreatic islet endothelial cells express coxsackievirus and adenovirus receptor and are activated by coxsackie B virus infection. FASEB J 2007; 21:3308-17. [PMID: 17494992 DOI: 10.1096/fj.06-7905com] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Enteroviruses, such as the coxsackievirus (CV) group, have been linked to the induction of inflammatory and autoimmune diseases. Virus tropism and tissue access are modulated by endothelial cells. To examine the susceptibility of microvascular endothelial cells (MECs) derived from pancreatic islets to infection with CV group B (CVB), purified cultured human islet MECs were infected with CVB-4 strain, and the immunological phenotype of the infected cells was analyzed. CVB-4 persistently infected the islet MECs, which expressed the CV receptors human coxsackievirus and adenovirus receptor (HCAR) and decay accelerating factor (DAF) and maintained EC characteristics, without overt cytopathic effects. CVB-4 infection transiently up-regulated expression of the adhesion molecules ICAM-1 and VCAM-1 and increased production of the proinflammatory cytokines IL-1beta and IL-6, and chemokines IL-8 and lymphotactin, as well as IFN-alpha. Mononuclear cell adhesion to CVB infected monolayers was increased, compared to uninfected monolayers. Moreover, infection up-regulated the viral receptors HCAR and DAF and coreceptor alpha(v)beta3 integrin on islet MECs, while down-regulating expression of HCAR on human aortic endothelial cells, indicating potential tissue-specific influence on the pathological outcome of infection. These results provide evidence that islet MECs are natural targets and reservoirs for persistent CVB infection resulting in acute endothelial cell activation by virus, which may contribute to selective recruitment of subsets of leukocytes during inflammatory immune responses, such as insulitis in type 1 diabetes.
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Affiliation(s)
- Maria M Zanone
- Department of Internal Medicine, University of Torino, Italy.
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19
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Abstract
People with type 1 diabetes have normal exocrine pancreatic function, making islet cell rather than whole organ transplantation an attractive option. Achieving insulin independence in type 1 diabetes was the perceived goal of islet cell transplantation. The success of the Edmonton group in achieving this in a selected group of type 1 patients has led to renewed optimism that this treatment could eventually replace whole organ pancreas transplantation. However the long-term results of this treatment indicate that insulin independence is lost with time in a significant proportion of patients, although they may retain glycaemic stability. In this context, the indications for islet cell transplantation, which have evolved over the last 5 years, indicate that the patients who benefit most are those who experience severe hypoglycaemic reactions despite optimal insulin therapy. This review will summarise the history of islet cell transplantation, islet isolation techniques, the transplant procedure, immunosuppressive therapy, indications for islet cell transplantation, current clinical trials, the early UK islet cell transplant experience using the Edmonton protocol, and some of the challenges that lie ahead.
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Affiliation(s)
- P Srinivasan
- King's College London School of Medicine at King's College Hospital, Institute of Liver Studies and Diabetes Research Group, King's College Hospital, London, UK
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20
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Ramracheya RD, Muller DS, Wu Y, Whitehouse BJ, Huang GC, Amiel SA, Karalliedde J, Viberti G, Jones PM, Persaud SJ. Direct regulation of insulin secretion by angiotensin II in human islets of Langerhans. Diabetologia 2006; 49:321-31. [PMID: 16416272 DOI: 10.1007/s00125-005-0101-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Accepted: 10/06/2005] [Indexed: 01/13/2023]
Abstract
AIMS/HYPOTHESIS This study aimed to identify the expression of angiotensin II receptors in isolated human islets and beta cells and to examine the functional consequences of their activation. MATERIALS AND METHODS Single-cell RT-PCR was used to identify whether human islet cells express mRNA for type 1 angiotensin II receptors (AT(1)), and western blotting was used to determine AT(1) protein expression by human islets and MIN6 beta cells. We measured changes in intracellular calcium by microfluorimetry using Fura 2-loaded MIN6 cells and human islet cells. Dynamic insulin secretory responses were determined by RIA following perifusion of human islets and MIN6 cells. RESULTS Human islets expressed mRNAs for both the angiotensin precursor, angiotensinogen, and for angiotensin-converting enzyme. In addition, human and mouse beta cells expressed AT(1). These were functionally coupled to increases in intracellular calcium, which occurred at least in part through phospholipase-C-sensitive mechanisms and calcium influx through voltage-operated calcium channels. Short-term exposure of human islets and MIN6 cells to angiotensin II caused a rapid, short-lived initiation of insulin secretion at 2 mmol/l glucose and potentiation of insulin secretion induced by glucose (at 8 and 16.7 mmol/l). CONCLUSIONS/INTERPRETATION These data demonstrate that the AT(1) is expressed by beta cells and that angiotensin II effects a short-lived and direct stimulation of human and mouse beta cells to promote insulin secretion, most probably through elevations in intracellular calcium. Locally produced angiotensin II may be important in regulating a coordinated insulin secretory response from beta cells.
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Affiliation(s)
- R D Ramracheya
- Beta Cell Development and Function Group, Division of Reproductive Health, Endocrinology and Development, King's College London, Room 2.9N Hodgkin Building Guy's Campus, London SE1 1UL, UK
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Favaro E, Bottelli A, Lozanoska-Ochser B, Ferioli E, Huang GC, Klein N, Chiaravalli A, Perin PC, Camussi G, Peakman M, Conaldi PG, Zanone MM. Primary and immortalised human pancreatic islet endothelial cells: phenotypic and immunological characterisation. Diabetologia 2005; 48:2552-62. [PMID: 16292462 DOI: 10.1007/s00125-005-0008-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2005] [Accepted: 07/21/2005] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS Studies on the biology of the microvascular endothelial cells (MECs) that surround and penetrate the pancreatic islets are hampered by difficulties in isolating and culturing large numbers of pure cells. We aimed to morphologically and functionally characterise primary MECs purified and cultured from human islets, and to establish a simian virus 40 (SV40)-immortalised cell line from these primary cultures. MATERIALS AND METHODS Human islet MECs were extracted and purified using anti-CD105 coated immunomagnetic beads, and endothelial markers and surface molecules analysed by flow cytometric analysis. An immortalised cell line was then established by using a chimeric adeno5/SV40 virus. RESULTS Islet MECs expressed classic and specific endothelial markers, a high basal level of intercellular adhesion molecule-1, and low levels of E-selectin and TNF (previously known as TNF-alpha) inducible vascular cell adhesion molecule-1. IFNG (previously known as IFN-gamma) induced expression of HLA class II molecules. The immortalised islet MECs expanded rapidly, exhibited increased DNA synthesis, and were passaged approximately 30 times, without signs of senescence. They retained the endothelial characteristics of the parental cells, and behaved as the primary cells in terms of TNF stimulation of expression of adhesion molecules and support of leucocyte adhesion and transmigration. CONCLUSIONS/INTERPRETATION The immortalised islet MECs that we have established could effectively represent a substitute for primary counterparts for in vitro studies on the role of the microvasculature in pathophysiological processes involved in type 1 and type 2 diabetes.
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Affiliation(s)
- E Favaro
- Department of Internal Medicine and Center of Experimental Medicine (CeRMS), University of Turin, Turin, Italy
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Zhao M, Amiel SA, Christie MR, Rela M, Heaton N, Huang GC. Insulin-producing cells derived from human pancreatic non-endocrine cell cultures reverse streptozotocin-induced hyperglycaemia in mice. Diabetologia 2005; 48:2051-61. [PMID: 16132961 DOI: 10.1007/s00125-005-1888-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2004] [Accepted: 04/27/2005] [Indexed: 10/25/2022]
Abstract
AIMS/HYPOTHESIS The aim of the study was to investigate the potential of human pancreatic non-endocrine cells to transdifferentiate into endocrine cells that would be capable of secreting insulin in response to glucose and ameliorating insulin-deficient diabetes after transplantation. MATERIALS AND METHODS Cell fractions enriched with exocrine cells after human islet isolation were treated with streptozotocin to remove residual beta cells, grown in monolayer culture to allow de-differentiation, transferred to cluster culture for redifferentiation in the presence of activin A, betacellulin, nicotinamide and glucose, supplemented with 10% FCS, and administered to streptozotocin-induced diabetic SCID mice. A subset of cells was transfected with the IPF1 gene (also known as PDX1) before transdifferentiation. RESULTS No insulin was detectable in cell preparations after 5 days of treatment with streptozotocin. In monolayer culture, 90% of the streptozotocin-treated pancreatic cells co-expressed cytokeratin-19 and vimentin at 2 weeks and 60% expressed nestin at 4 weeks. Cell cultures with a high proportion of nestin-expressing cells had greater plasticity for transdifferentiation into cells with phenotypic and functional markers of beta cells, this property being significantly enhanced by transfection with IPF1 gene and leading to 15+/-6.7% insulin-positive cells after transplantation vs. 0.01% of cells transplanted after streptozotocin treatment alone. These cells improved glucose control in all of 42 diabetic mice after transplantation, restoring normoglycaemia in 40%. CONCLUSIONS/INTERPRETATION Human pancreatic cells are a potential source of new glucose-responsive insulin-producing cells that may be developed further for clinical use.
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Affiliation(s)
- M Zhao
- Department of Diabetes, Endocrinology and Internal Medicine, King's College GKT Medical School, Bessemer Road, London SE5 9PJ, UK
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23
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Zanone MM, Favaro E, Doublier S, Lozanoska-Ochser B, Deregibus MC, Greening J, Huang GC, Klein N, Cavallo Perin P, Peakman M, Camussi G. Expression of nephrin by human pancreatic islet endothelial cells. Diabetologia 2005; 48:1789-97. [PMID: 16010520 DOI: 10.1007/s00125-005-1865-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2004] [Accepted: 04/18/2005] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS The islet microcirculation has morphological characteristics resembling those of renal glomeruli. Transcription of the nephrin gene, a highly specific barrier protein of the slit diaphragm of podocyte foot processes, has been reported in the pancreas, although its cellular localisation and function remain to be defined. In this study, we purified and characterised microvascular endothelial cells (MECs) isolated from human islets and investigated the expression and distribution of nephrin on these cells. METHODS Human islet MECs were extracted and purified using anti-CD105-coated immunomagnetic beads and their endothelial characteristics were confirmed by expression of classical endothelial markers and basal high-level expression of intercellular adhesion molecule-1 and TNF-alpha-inducible vascular cell adhesion molecule-1. Nephrin expression was assessed by immunofluorescence, flow cytometric analysis and western blotting on cell lysates, as well as by RT-PCR. RESULTS Immunofluorescence studies detected nephrin in a fine, punctate, diffuse pattern on cultured islet MECs, and also in human pancreatic islet sections. In both cases nephrin colocalised with endothelial markers. TNF-alpha treatment induced a marked reduction and redistribution of the protein in one or multiple aggregates. Nephrin expression was confirmed by flow cytometry, western blotting and RT-PCR studies. In contrast, nephrin could not be detected at the protein or mRNA level in human macro- and microvascular cells from other sites. CONCLUSIONS/INTERPRETATION Nephrin is expressed at protein and mRNA levels in islet microendothelium, supporting the hypothesis that islet MECs exhibit distinctive morphological characteristics that indicate functional specialisation of potential pathophysiological importance.
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Affiliation(s)
- M M Zanone
- Department of Internal Medicine and Centre of Experimental Medicine (CeRMS), University of Torino, Corso Dogliotti 14, Torino, Italy.
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Al-Majed HT, Jones PM, Persaud SJ, Sugden D, Huang GC, Amiel S, Whitehouse BJ. ACTH stimulates insulin secretion from MIN6 cells and primary mouse and human islets of Langerhans. J Endocrinol 2004; 180:155-66. [PMID: 14709154 DOI: 10.1677/joe.0.1800155] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
It has previously been suggested that ACTH and ACTH-related peptides may act as paracrine modulators of insulin secretion in the islets of Langerhans. We have, therefore, examined the expression and function of the ACTH receptor (the melanocortin 2 receptor, MC2-R) in human and mouse primary islet tIssue and in the MIN6 mouse insulinoma cell line. Mouse MC2-R mRNA was detected in both MIN6 cells and mouse islet tIssue by PCR amplification of cDNA. In perifusion experiments with MIN6 pseudo-islets, a small, transient increase in insulin secretion was obtained when ACTH(1-24) (1 nM) was added to medium containing 2 mM glucose (control) but not when the medium glucose content was increased to 8 mM. Further investigations were performed using static incubations of MIN6 cell monolayers; ACTH(1-24) (1 pM-10 nM) provoked a concentration-dependent increase in insulin secretion from MIN6 monolayer cells that achieved statistical significance at concentrations of 1 and 10 nM (150 +/- 13.6% basal secretion; 187 +/- 14.9% basal secretion, P<0.01). Similar responses were obtained with ACTH(1-39). The phosphodiesterase inhibitor IBMX (100 microM) potentiated the responses to sub-maximal doses of ACTH(1-24). Two inhibitors of the protein kinase A (PKA) signaling pathway, Rp-cAMPS (500 microM) and H-89 (10 microM), abolished the insulin secretory response to ACTH(1-24) (0.5-10 nM). Treatment with 1 nM ACTH(1-24) caused a small, statistically significant increase in intracellular cAMP levels. Secretory responses of MIN6 cells to ACTH(1-24) were also influenced by changes in extracellular Ca2+ levels. Incubation in Ca2+-free buffer supplemented with 0.1 mM EGTA blocked the MIN6 cells' secretory response to 1 and 10 nM ACTH(1-24). Similar results were obtained when a Ca2+ channel blocker (nitrendipine, 10 microM) was added to the Ca2+-containing buffer. ACTH(1-24) also evoked an insulin secretory response from primary tIssues. The addition of ACTH(1-24) (0.5 nM) to perifusions of mouse islets induced a transient increase in insulin secretion at 8 mM glucose. Perifused human primary islets also showed a secretory response to ACTH(1-24) at basal glucose concentration (2 mM) with a rapid initial spike in insulin secretion followed by a decline to basal levels. Overall the results demonstrate that the MC2-R is expressed in beta-cells and suggest that activation of the receptor by ACTH initiates insulin secretion through the activation of PKA in association with Ca2+ influx into beta-cells.
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Affiliation(s)
- H T Al-Majed
- Centre for Reproduction, Endocrinology and Diabetes, GKT School of Biomedical Sciences, King's College London, Guy's Campus, London SE1 1UL, UK
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Huang GC, Hobbs S, Walton M, Epstein RJ. Dominant negative knockout of p53 abolishes ErbB2-dependent apoptosis and permits growth acceleration in human breast cancer cells. Br J Cancer 2002; 86:1104-9. [PMID: 11953857 PMCID: PMC2364174 DOI: 10.1038/sj.bjc.6600219] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2002] [Accepted: 01/24/2002] [Indexed: 11/09/2022] Open
Abstract
We previously reported that the ErbB2 oncoprotein prolongs and amplifies growth factor signalling by impairing ligand-dependent downregulation of hetero-oligomerised epidermal growth factor receptors. Here we show that treatment of A431 cells with different epidermal growth factor receptor ligands can cause growth inhibition to an extent paralleling ErbB2 tyrosine phosphorylation. To determine whether such growth inhibition signifies an interaction between the cell cycle machinery and ErbB2-dependent alterations of cell signalling kinetics, we used MCF7 breast cancer cells (which express wild-type p53) to create transient and stable ErbB2 transfectants (MCF7-B2). Compared with parental cells, MCF7-B2 cells are characterised by upregulation of p53, p21(WAF) and Myc, downregulation of Bcl2, and apoptosis. In contrast, MCF7-B2 cells co-transfected with dominant negative p53 (MCF7-B2/Delta p53) exhibit reduced apoptosis and enhanced growth relative to both parental MCF7-B2 and control cells. These data imply that wild-type p53 limits survival of ErbB2-overexpressing breast cancer cells, and suggest that signals of varying length and/or intensity may evoke different cell outcomes depending upon the integrity of cell cycle control genes. We submit that acquisition of cell cycle control defects may play a permissive role in ErbB2 upregulation, and that the ErbB2 overexpression phenotype may in turn select for the survival of cells with p53 mutations or other tumour suppressor gene defects.
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Affiliation(s)
- G C Huang
- Department of Medicine, King's College School of Medicine, Bessemer Rd, London, SW3, UK
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26
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Yamagata T, Ishii M, Narita M, Huang GC, Endo G. Bio-affecting mercury detection using mercury resistance gene module fused with bioluminescence reporter genes. Water Sci Technol 2002; 46:253-256. [PMID: 12523762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Bioluminescence sensor systems were developed for monitoring environmental mercury contamination. The biological mercury measurement sensor systems were constructed by DNA recombination technique. A bacterial mercury-resistant operon (meroperon) from Pseudomonas sp. K-6y4 and a bacterial bioluminescence operon (lux operon) from an ocean bacterium Vibrio fischeri were fused in avector plasmid. The resulting recombinant plasmids were cloned in Escherichia coli cells. The bioluminescence sensor systems responded to mercury chloride of 0.1 nM to 100 nM. The mercury bioluminescence sensor developed in this study can be used for monitoring of the bio-affecting mercury instead of total mercury that is measured by conventional analytical equipment. The fundamental feature of the bioluminescence sensor system is attractive for use as a monitoring system for bio-affecting environmental mercury contamination.
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Affiliation(s)
- T Yamagata
- Faculty of Engineering, Tohoku Gujuin University, 1-13-1 Chuo, Tagajo 985-8537, Japan
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27
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Qin ZJ, Tang YQ, Jing GZ, Li ZY, Huang GC, Perrett S, Guo ZQ, Zhou JM. Conformational adjustments of SNase R and its N-terminal fragments probed by monoclonal antibodies. Biochim Biophys Acta 2001; 1548:203-12. [PMID: 11513965 DOI: 10.1016/s0167-4838(01)00231-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two monoclonal antibodies specific for staphylococcal nuclease R (SNase R) (McAb2C9 and McAb1B8) were prepared and used to probe protein folding during peptide elongation, by measuring antibody binding to seven N-terminal fragments (SNR141, SNR135, SNR121, SNR110, SNR102, SNR79 and SNR52) of SNase R. Comparative studies of the conformations of the N-terminal fragments have shown that all seven fragments of SNase R have a certain amount of residual structure, indicating that folding may occur during elongation of the nascent peptide chain. We show that the binding abilities of the intact enzyme and its seven fragments to the monoclonal antibodies are not simply proportional to the length of the peptide chain, suggesting that there may be continuous conformational adjustment in the nascent peptide chain as new C-terminal amino acids are added. A folding intermediate close in structure to the native state but with structural features in common with SNR121 is highly populated in 0.6 M GuHCl, and is also formed transiently during folding.
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Affiliation(s)
- Z J Qin
- National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, Beijing, PR China
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28
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Ouyang X, Gulliford T, Huang GC, Harper-Wynne C, Shousha S, Epstein RJ. Multisite phosphotyping of the ErbB-2 oncoprotein in human breast cancer. Mol Diagn 2001; 6:17-25. [PMID: 11257208 DOI: 10.1054/modi.2001.21638] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Overexpression of the ErbB-2 (HER2/neu) receptor tyrosine kinase is one of the most common molecular changes in human cancer, but the functional significance of this phenotype remains uncertain. METHODS AND RESULTS Using phosphorylation-specific antibodies recognizing different ErbB-2 functional states, we assessed the phosphorylation status of ErbB-2 in 102 human breast cancer specimens. Quantitative ErbB-2 immunoblotting intensity correlated directly with that of immunohistochemistry (r = 0.84). Widely varying phosphorylation profiles were evident in 65 ErbB-2-positive carcinomas, suggesting different ErbB-2 functions in different tumors. In a subset of patients for whom clinical data were obtainable, mortality trends were strongly associated with the quantitative signal intensities of ErbB-2 phosphoantibodies (P < or =.02), but not with those of conventional antibodies to ErbB-2 (P = .147), epidermal growth factor receptor (P = .44), or phosphotyrosine (P = .94). CONCLUSION Although requiring corroboration in larger prospective clinical studies, these findings suggest that immunophenotyping using phosphorylation-specific antibodies may enable more accurate prediction of cancer behavior than is currently obtainable using conventional reagents.
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Affiliation(s)
- X Ouyang
- Division of Investigative Sciences, Imperial College School of Medicine, London, UK
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29
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Abstract
The Escherichia coli trigger factor is a peptidyl-prolyl cis-trans isomerase that catalyzes proline-limited protein folding extremely well. Here, refolding of D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in the presence of trigger factor was investigated. The regain of activity of GAPDH was markedly increased by trigger factor after either long- or short-term denaturation, and detectable aggregation of GAPDH intermediates was prevented. In both cases, time courses of refolding of GAPDH were decelerated by trigger factor. The reactivation yield of GAPDH showed a slow down-turn when molar ratios of trigger factor to GAPDH were above 5, due to tight binding between trigger factor and GAPDH intermediates. Such inactive bound GAPDH could be partially rescued from trigger factor by addition of reduced alphaLA as competitor, by further diluting the refolding mixture, or by disrupting hydrophobic interactions in the complexes. A model for trigger factor assisted refolding of GAPDH is proposed. We also suggest that assisted refolding of GAPDH is due mainly to the chaperone function of trigger factor.
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Affiliation(s)
- G C Huang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, Beijing, China
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Abstract
A burst phase occurs in the refolding kinetics of guanidine-denatured creatine kinase due to formation of an intermediate within the mixing dead time, with further refolding to the native state after the burst phase along a path following biphasic kinetics. In the presence of cyclophilin, the refolding rates of the two slow processes are accelerated and the values are proportional to the cyclophilin concentration. The activity of cyclophilin in accelerating the slow refolding processes of creatine kinase is totally inhibited by cyclosporin A, indicating that the cis-trans isomerization of the peptidyl-prolyl bonds is involved in the two slow refolding processes.
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Affiliation(s)
- G C Huang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, Beijing, China
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Ouyang X, Gulliford T, Doherty A, Huang GC, Epstein RJ. Detection of ErbB2 oversignalling in a majority of breast cancers with phosphorylation-state-specific antibodies. Lancet 1999; 353:1591-2. [PMID: 10334266 DOI: 10.1016/s0140-6736(99)01095-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Huang GC, Sheu BS, Tsao CJ, Lin XZ, Su IJ. Eradiction of H. pylori results in regression of B-cell low grade gastric MALToma with evident B-symptoms. Hepatogastroenterology 1998; 45:2464-7. [PMID: 9951945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Although it is well known that eradication of H. pylori may result in either complete or partial regression of low-grade B-cell mucosa-associated lymphoid tissue lymphoma (MALToma), it would be of clinical interest to determine whether the B-symptoms of patients with MALToma could be relieved by eradication of H. pylori. Here, we report on a 29 year-old female case with B-cell low-grade gastric MALToma with apparent B-symptoms. Her peripheral blood also disclosed large granular lymphocytes (LGL). The B-symptoms of this patient were quickly relieved within 2 weeks after starting an anti-H. pylori regimen; peripheral blood LGLs were clearly decreased as well. Complete regression of MALToma was determined 4 months after the anti-H. pylori regimen. Thereafter, the patient has been disease-free and in good general condition during a 2-year follow-up.
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Affiliation(s)
- G C Huang
- The Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan, ROC
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33
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Ko WC, Chuang YC, Huang GC, Hsu SY. Infections due to non-O1 Vibrio cholerae in southern Taiwan: predominance in cirrhotic patients. Clin Infect Dis 1998; 27:774-80. [PMID: 9798033 DOI: 10.1086/514947] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Although Taiwan is not an area where cholera is endemic, from October 1988 to October 1997 30 episodes of non-O1, non-O139 Vibrio cholerae infection were noted at the National Cheng Kung University Hospital in Taiwan. Infections generally occurred in hot seasons, and two episodes were concomitant with Vibrio vulnificus infection. Three major clinical presentations were found: bacteremia with concurrent spontaneous bacterial peritonitis or invasive soft-tissue infections that occurred solely in cirrhotic patients; self-limited acute febrile gastroenteritis that occurred in patients with no underlying medical disease; and necrotizing fasciitis or cellulitis that often resulted from a wound on extremities. Other manifestations included fatal pneumonitis in a drowned man and acute pyosalpinx. The differential diagnosis of invasive infections in cirrhotic patients should include infections due to non-O1 V. cholerae or V. vulnificus, and a third-generation cephalosporin and a tetracycline analogue or a fluoroquinolone alone is recommended for treatment of severe vibrio infections.
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Affiliation(s)
- W C Ko
- Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan
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Ouyang X, Huang GC, Chantry A, Epstein RJ. Adjacent carboxyterminal tyrosine phosphorylation events identify functionally distinct ErbB2 receptor subsets: implications for molecular diagnostics. Exp Cell Res 1998; 241:467-75. [PMID: 9637788 DOI: 10.1006/excr.1998.4091] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Site-directed mutagenesis can define the effects of altering one or more amino acids within a protein, but this technique may lack sensitivity when used to characterize proteins which differ conformationally or posttranslationally at multiple sites. A novel alternative approach involves the direct characterization of wild-type protein isoforms identified by site-specific immunodetection. To this end we have developed antibodies which recognize ErbB2 subsets characterized by adjacent tyrosine phosphorylation events (Y1222 and Y1248) in the C-terminal tail of the oncoprotein. Here we use these phosphoantibodies to demonstrate the existence of tyrosine-phosphorylated ErbB2 subsets which differ in their patterns of heterooligomer formation, in vitro autophosphorylation, and recruitment of SH2-containing substrates. Furthermore, Y1222 and/or Y1248 phosphoantibody immunoreactivity is readily detectable in ErbB2-overexpressing human breast tumors, in which context these phosphorylation events exhibit significant discordance. These data confirm the value of site-specific immunodetection as a strategy for characterizing phosphoprotein function in vitro and in vivo and suggest that multisite phosphotyping of human tumors may contribute novel clinicopathologic insights into the significance of the ErbB2 overexpression phenotype.
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Affiliation(s)
- X Ouyang
- Department of Metabolic Medicine, Imperial College School of Medicine, London, W12 0NN, United Kingdom
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Abstract
The unfolding of creatine kinase in various concentrations of guanidine hydrochloride of increasing concentrations has been investigated by combination of size-exclusion chromatography (SEC) with other methods. There are two peaks in the profiles of SEC in GuHCl at moderate concentrations, showing that unfolding of creatine kinase goes through dimeric and monomeric intermediates with increasing guanidine hydrochloride concentrations. Both intermediates have relatively compact structure and retain considerable ordered structure.
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Affiliation(s)
- Y L Zhang
- National Laboratory of Biomacromolecules, Academia Sinica, Beijing, China
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Huang GC, Ouyang X, Epstein RJ. Proxy activation of protein ErbB2 by heterologous ligands implies a heterotetrameric mode of receptor tyrosine kinase interaction. Biochem J 1998; 331 ( Pt 1):113-9. [PMID: 9512468 PMCID: PMC1219327 DOI: 10.1042/bj3310113] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The oncoprotein ErbB2 is frequently overexpressed in human tumours, but no activating ErbB2-specific ligand has yet been identified. Here we analyse the catalytic and oligomeric behaviour of ErbB2 using phosphorylation-state-specific antibodies which distinguish kinase-active and -inactive ErbB2 receptor subsets. Heregulin-alpha (HRG) activates ErbB2 in G8/DHFR 3T3 cells by selectively inducing hetero-oligomerization with kinase-defective ErbB3, indicating that heterologous transphosphorylation is an unlikely prerequisite for ErbB2 activation. HRG also triggers association of epidermal-growth-factor receptors (EGFR) with a kinase-inactive ErbB2 subset while reducing EGFR association with active ErbB2. Similarly, EGF treatment of A431 cells induces concomitant hetero-oligomerization of active ErbB2 with inactive EGFR, of active EGFR with inactive ErbB2, and of inactive ErbB2 with kinase-defective ErbB3. These combinatorial patterns of ligand-dependent oligomerization suggest a multivalent model of receptor tyrosine kinase interaction in which liganded homodimers provide stable oligomerization interfaces for unliganded ErbB2 or other bystander receptors. We submit that ErbB2 may be physiologically activated via a 'proxy' ligand-inducible heterotetrameric mechanism similar to that already established for transforming-growth-factor-beta type I receptors.
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Affiliation(s)
- G C Huang
- Department of Oncology, Imperial College School of Medicine, London W6 8RF, U.K
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Gulliford TJ, Huang GC, Ouyang X, Epstein RJ. Reduced ability of transforming growth factor-alpha to induce EGF receptor heterodimerization and downregulation suggests a mechanism of oncogenic synergy with ErbB2. Oncogene 1997; 15:2219-23. [PMID: 9393980 DOI: 10.1038/sj.onc.1201595] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The epidermal growth factor receptor (EGFR) is activated by a variety of ligands including EGF and transforming growth factor-alpha (TGFalpha), whereas no ligand for the homologous ErbB2 oncoprotein has yet been identified. Here we use both an ErbB2 phosphoantibody (aPY1222) and an activation-specific EGFR antibody to show that low concentrations of EGF induce more efficient tyrosine phosphorylation of ErbB2 in A431 cells than does equimolar TGFalpha, while EGFR is more potently activated by TGFalpha. Co-precipitation studies confirm that heterodimerization of activated EGFR and transphosphorylated ErbB2 is readily induced by EGF but not TGFalpha. EGFR downregulation is also more efficiently induced by EGF, suggesting that ligand-dependent modification of ErbB2 may be required to terminate EGFR signalling in cells expressing both receptor types. These findings indicate that EGF and TGFalpha differ in their abilities to induce tyrosine phosphorylation and heterodimerization of ErbB2, and raise the possibility that ErbB2 exerts its oncogenic effect in part by impairing TGFalpha-dependent EGFR downregulation.
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Affiliation(s)
- T J Gulliford
- Division of Medicine, Imperial College School of Medicine, Charing Cross Hospital, London, UK
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Ouyang X, Gulliford T, Zhang H, Huang GC, Epstein R. Human cancer cells exhibit protein kinase C-dependent c-erbB-2 transmodulation that correlates with phosphatase sensitivity and kinase activity. J Biol Chem 1996; 271:21786-92. [PMID: 8702975 DOI: 10.1074/jbc.271.36.21786] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The c-erbB-2 receptor tyrosine kinase is often overexpressed in human tumors, but the functional implications of this phenotype remain unclear. We previously used phosphorylation-specific antibodies to define major differences in c-erbB-2 tyrosine kinase activity between overexpressing human tumor cell lines (Epstein, R. J., Druker, B. J., Roberts, T. M., and Stiles, C. D. (1992) Proc. Natl. Acad. Sci. U. S. A. 89, 10435-10439). Here we extend this approach to define the relationship between c-erbB-2 tyrosine phosphorylation and protein kinase C (PKC)-dependent transmodulation. Phosphorylation-specific antibodies to the juxtamembrane PKC site Thr686 recognize tyrosine-dephosphorylated wild-type c-erbB-2 following G8/DHFR 3T3 cell treatment with PKC agonists. B104-1-1 cells transformed by activated c-erbB-2 express a subset of tyrosine-phosphorylated receptors that are homologously phosphorylated on Thr686, indicating that Thr686 phosphorylation alone is insufficient to abrogate receptor tyrosine phosphorylation. Similarly, the c-erbB-2-overexpressing human cancer cell lines SK-Ov-3 and BT-474 express constitutively Thr686-phosphorylated receptors. SK-Ov-3 cells express predominantly kinase-inactive c-erbB-2 that is heavily Thr686-phosphorylated, indicating that Thr686 phosphorylation in this line is heterologous in origin. In contrast, BT-474 cells express constitutively autophosphorylated c-erbB-2 despite Thr686 phosphorylation. These results indicate that Thr686 phosphorylation does not directly abolish c-erbB-2 activity and suggest that such phosphorylation reflects constitutive PKC activity induced by either receptor-activating mutations or heterologous growth factors. The latter possibility suggests in turn that c-erbB-2 interacts in an as yet undefined way with heterologous growth factor receptors in human tumor cells.
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Affiliation(s)
- X Ouyang
- Division of Cell, Molecular and Oncology Research, Charing Cross and Westminster Medical School, University of London
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Morgenthaler NG, Kim MR, Tremble J, Huang GC, Richter W, Gupta M, Scherbaum WA, McGregor AM, Banga JP. Human immunoglobulin G autoantibodies to the thyrotropin receptor from Epstein-Barr virus-transformed B lymphocytes: characterization by immunoprecipitation with recombinant antigen and biological activity. J Clin Endocrinol Metab 1996; 81:3155-61. [PMID: 8784060 DOI: 10.1210/jcem.81.9.8784060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The TSH receptor (TSH-R) is the target antigen for disease-related autoantibodies in Graves' disease and primary myxoedema, but the repertoire of the antibodies or the nature of the precise antigenic epitopes is not known. We have immortalized peripheral blood B cells from six different autoimmune thyroid disease patients with Epstein-Barr virus and selected IgG-producing B cells by magnetic selection on anti-IgG-coated beads. Purified recombinant insect cell-derived extracellular region of TSH-R was used to identify the positive wells for expansion in culture. Stable B cell lines (n = 11) were obtained, which after limiting dilution led to two stable B cell clones. B cell lines and clones secreted IgG antibody that were shown to react biochemically with metabolically labeled or in vitro translated, nascent extracellular region of TSH-R, giving strong, confirmatory evidence of the presence of anti-TSH-R antibody. Supernatants from lines contained thyroid-stimulating activity, thyroid-blocking activity (as assessed by inhibition of TSH-mediated cAMP stimulation), or both of these activities. Interestingly, antibodies with stimulating activity were generated from a primary myxoedema patient, and antibodies of blocking specificities were obtained from newly diagnosed thyrotoxic Graves' disease patients. Our results favor a fine balance between stimulating and blocking autoantibody activities in determining the clinical presentation observed in patients with autoimmune thyroid disease patients who have these antibodies present in their serum.
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Affiliation(s)
- N G Morgenthaler
- Department of Medicine, King's College School of Medicine, London, United Kingdom
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Nicholson LB, Vlase H, Graves P, Nilsson M, Molne J, Huang GC, Morgenthaler NG, Davies TF, McGregor AM, Banga JP. Monoclonal antibodies to the human TSH receptor: epitope mapping and binding to the native receptor on the basolateral plasma membrane of thyroid follicular cells. J Mol Endocrinol 1996; 16:159-70. [PMID: 9156519 DOI: 10.1677/jme.0.0160159] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have characterized four murine monoclonal antibodies (mAbs) to the extracellular domain of the human TSH receptor (TSH-R.E), the target autoantigen of Graves' disease. Recombinant TSH-R.E used as immunogen, was produced in E. coli as a fusion protein with glutathione-S-transferase or in a baculovirus-insect cell system, as a non-fusion glycoprotein. To increase the epitope specificity of the mAbs, two different strains of mice (H-2(b) and H-2(d)) were immunized. The epitopes recognized by the mAbs were characterized by immunoblotting with various recombinant constructs of TSH-R.E and by binding to overlapping synthetic peptides of the receptor. The four IgG mAbs characterized recognized epitopes localized to different regions on the TSH-R.E; amino acids 22-35 (A1O and A11, both IgG2b from H-2(b) animals), amino acids 402-415 (A7, IgG2b from H-2(b) animals) and amino acids 147-228 (A9, IgG1 from H-2(d) animals). Immunolocalization studies showed that mAb A9 recognized TSH-R.E on unfixed cryostat sections, where binding was localized to the basolateral plasma membrane of thyroid follicular cells, suggesting that this antibody reacts with the native receptor on thyroid cells. The binding of the mAbs A7, A10 and A11 was also restricted to the basal surface of thyroid cells, but only after acetone fixation of the sections, implying that the epitopes recognized on the amino and carboxyl terminus of the extracellular region of the receptor are not accessible on the native molecule. None of the mAbs stimulated cyclic AMP responses in COS-7 cells transiently transfected with full-length functioning TSH-R.E, whilst weak inhibition of binding of radiolabelled TSH to porcine membranes in a radioreceptor assay was apparent with mAb A10 and A11, but only at high concentrations of IgG. The ability of mAb A9 to bind to the native receptor without stimulating activity or inhibition of TSH binding suggests that antibody can bind to the central region of the TSH-R.E without perturbing receptor function. The availability of mAbs that recognize epitopes on different regions of the extracellular domain of TSH-R will lead to a better understanding of the autoantigenic regions on TSH-R implicated in disease activity.
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Affiliation(s)
- L B Nicholson
- Department of Medicine, King's College School of Medicine, London, UK
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41
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Huang GC, Tremble J, Bailyes E, Arden SD, Kaye T, McGregor AM, Banga JP. HLA-DR-restricted T cell lines from newly diagnosed type 1 diabetic patients specific for insulinoma and normal islet beta cell proteins: lack of reactivity to glutamic acid decarboxylase. Clin Exp Immunol 1995; 102:152-8. [PMID: 7554382 PMCID: PMC1553330 DOI: 10.1111/j.1365-2249.1995.tb06649.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
T cells reacting with pancreatic islet beta cell proteins play a pivotal role in the pathogenesis of type 1 diabetes in experimental animal models and man, although the islet cell autoantigens against which these T cells are directed remain to be characterized. We have previously shown the presence of disease-related antigens residing in the transplantable RIN insulinoma membranes which are recognized by T cells from diabetic NOD mice. We now report on the establishment of CD4+, T cell lines reacting with insulinoma membranes from six newly diagnosed type 1 diabetic patients. Detailed examination of T cell lines from two patients revealed that both the lines continued to react with normal islet cell proteins and, interestingly, were also stimulated by antigens present in brain microsomes. The two T cell lines showed reactivity with different molecular weight proteins of the insulinoma membranes and both the lines were histocompatibility-linked antigen (HLA)-DR restricted. Although the insulinoma membrane preparation is known to contain glutamic acid decarboxylase (GAD), none of the six T cell lines proliferates in response to purified GAD. These T cell lines will be valuable in characterizing novel islet beta cell antigens which are likely to be implicated in type 1 diabetes.
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Affiliation(s)
- G C Huang
- Department of Medicine, King's College School of Medicine, London, UK
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Carayanniotis G, Huang GC, Nicholson LB, Scott T, Allain P, McGregor AM, Banga JP. Unaltered thyroid function in mice responding to a highly immunogenic thyrotropin receptor: implications for the establishment of a mouse model for Graves' disease. Clin Exp Immunol 1995; 99:294-302. [PMID: 7851025 PMCID: PMC1534295 DOI: 10.1111/j.1365-2249.1995.tb05548.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Grave's disease (GD) is a common disorder characterized by the presence of autoantibodies to the thyrotropin receptor. In the past, the exceedingly low expression of the thyrotropin receptor on thyrocytes has not allowed its purification in quantities sufficient to investigate the establishment of an animal model for this disease. In this study, we have purified the 398-amino acid, extracellular region of the human thyrotropin receptor (TSH-R.E) from insect cells using recombinant baculovirus, and explored its immunopathogenic properties in H-2b,d,q,k,s strains of mice. The receptor preparation was highly immunogenic since it elicited strong specific proliferative T cell responses as well as IgG responses in all strains tested. In addition, hyperimmunization with TSH-R.E induced (i) serum antibodies that blocked the binding of 125I-TSH to its receptor, a common feature of GD autoantibodies; and (ii) IgG that reacted with a synthetic peptide (residues 32-54) from the N-terminus of the receptor, a region implicated in the binding of thyroid stimulating antibodies. In SJL animals only, a weak antibody response to two other thyroid antigens, thyroglobulin and thyroid peroxidase, was also observed. The presence of these antibodies, however, was not accompanied by a detectable alteration in thyroid function as assessed by the measurement of serum TSH, T4 and iodine levels. Also mononuclear infiltration of the thyroid gland or morphological changes compatible with an activation state of thyrocytes were not apparent in TSH-R-challenged mice. In contrast, mice treated with the anti-oxidant aminotriazole showed a dramatic increase in serum TSH levels and an activated follicular epithelium. These data demonstrate that a highly immunogenic TSH-R.E in mice does not necessarily provide a proper stimulus for the induction of a hyper- or hypothyroid status as defined by hormonal or histological criteria. Main reasons for the inability to induce receptor-specific antibodies that affect thyroid function such as those generated in GD are likely to be the inappropriate folding of the recombinant extracellular domain of the receptor, or the xenogeneic nature of the autoantigen.
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Affiliation(s)
- G Carayanniotis
- Faculty of Medicine, Memorial University of Newfoundland, St John's, Canada
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Song YH, Ma JY, Mårdh S, Liu T, Sjöstrand SE, Rask L, Borch K, Huang GC, Barnett P, McGregor AM. Localization of a pernicious anaemia autoantibody epitope on the alpha-subunit of human H,K-adenosine triphosphatase. Scand J Gastroenterol 1994; 29:122-7. [PMID: 7513438 DOI: 10.3109/00365529409090449] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Four cDNA fragments encoding different portions of the alpha-subunit of human H,K-adenosine triphosphatase (ATPase) were amplified by means of the polymerase chain reaction technique, ligated into the plasmid pGEX-2T, and expressed as glutathione S-transferase fusion proteins in Escherichia coli. The fragments A (residues 163-313), Ba (residues 360-797), Bb (residues 526-797), and C (residues 822-1031) together encompass 77% of the alpha-subunit and cover most of its cytosolic part. The reactivities of autoantibodies in the sera from patients with pernicious anaemia with the recombinant fusion proteins were analysed by immunoblotting. One autoantigenic epitope was found in the NH2-terminal part of the Ba fragment--that is, between residues 360 and 525. No epitope was detected in the other fragments. The Ba fragment was cleaved off from the glutathione S-transferase fusion protein by the action of thrombin and was then further purified. By means of enzyme-linked immunosorbent assay, 28 of 42 sera (67%) from patients with pernicious anaemia were positive against the purified Ba fragment. The present results provide a final proof that the human H,K-ATPase alpha-subunit is a major autoantigen in the parietal cell and that the major epitope is located between residues 360 to 525 on the cytosolic side of the secretory membrane.
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Affiliation(s)
- Y H Song
- Dept. of Medical and Physiological Chemistry, Uppsala University, Sweden
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Huang GC, Page MJ, Nicholson LB, Collison KS, McGregor AM, Banga JP. The thyrotrophin hormone receptor of Graves' disease: overexpression of the extracellular domain in insect cells using recombinant baculovirus, immunoaffinity purification and analysis of autoantibody binding. J Mol Endocrinol 1993; 10:127-42. [PMID: 8484862 DOI: 10.1677/jme.0.0100127] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Since the cloning of the TSH receptor (TSH-R), the target autoantigen of Graves' disease, the receptor has been expressed in a variety of eukaryotic cells to obtain a functional molecule. Despite this success, the levels of receptor expression have been marginally higher than the extremely low levels found in thyroid cells, preventing any progress on the purification of the molecule. In this study, the large extracellular region of the TSH-R, without the membrane spanning segments, has been expressed in insect cells using recombinant baculovirus to generate substantial quantities of the receptor protein. A monoclonal antibody previously generated to a bacterial TSH-R fusion protein was used to characterize and monitor the expression of the truncated receptor in insect cells. Two polypeptides of 63 and 49 kDa were recognized as the components of the truncated recombinant receptor. The 63 kDa protein was shown to be the glycosylated form of the smaller, 49 kDa, component. Expression in different insect cell lines showed that an increase in expression of approximately tenfold was apparent in High Five cells when compared with Sf21 cells. Very small quantities of the truncated receptor were secreted by the three insect cell lines examined, with the majority of the molecule being retained within the cells. Immunoaffinity purification of milligram quantities of the truncated receptor was achieved using the monoclonal antibody. The availability of the purified TSH-R has allowed the establishment of an enzyme-linked immunosorbent assay to measure autoantibodies in the sera of patients with Graves' disease. Although the truncated receptor interacts with autoantibodies, our results show that it does not bind TSH and differs in this respect from other glycoprotein hormone receptors.
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Affiliation(s)
- G C Huang
- Department of Medicine, King's College School of Medicine, Denmark Hill, London, UK
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45
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Huang GC, Collison KS, McGregor AM, Banga JP. Expression of a human thyrotrophin receptor fragment in Escherichia coli and its interaction with the hormone and autoantibodies from patients with Graves' disease. J Mol Endocrinol 1992; 8:137-44. [PMID: 1515018 DOI: 10.1677/jme.0.0080137] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Graves' disease is an autoimmune thyroid disease characterized by the presence of pathogenic autoantibodies to the TSH receptor (TSH-R). By using polymerase chain reaction, the extracellular region of the human TSH-R cDNA has been amplified and used to prepare recombinant TSH-R (extracellular) protein fused with glutathione-S-transferase (GST). Purification of the recombinant TSH-R (extracellular)-GST fusion protein was achieved by preparative gel electrophoresis in SDS or by preparative isoelectric focusing in urea. Following removal of SDS by detergent exchange or urea by dialysis, the purified recombinant receptor preparations were assessed for binding to the hormone or to autoantibodies from Graves' disease patients. The purified recombinant receptor preparations fail to show any binding to the hormone or autoantibodies either by inhibition of binding assays or by immunoblotting. The results imply that the correct folding and/or post-translational modifications of the polypeptide chain which are not achieved in recombinant proteins produced in Escherichia coli may be important for the binding of the hormone or Graves' disease autoantibodies to the TSH-R. The recombinant receptor prepared in this manner will be useful for immunological and cellular investigations in patients with Graves' disease.
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Affiliation(s)
- G C Huang
- Department of Medicine, King's College School of Medicine and Dentistry, Denmark Hill, London
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Collison KS, Banga JP, Barnett PS, Huang GC, McGregor AM. Autoantibody stimulation of the human thyrotropin receptor: regulation of adenylate cyclase activity, thyroglobulin and thyroid peroxidase mRNA levels in primary cultures of Graves' thyroid tissue. Clin Exp Immunol 1991; 86:61-5. [PMID: 1914236 PMCID: PMC1554159 DOI: 10.1111/j.1365-2249.1991.tb05774.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The effects of immunoglobulin preparations from hyperthyroid Graves' disease patients on primary cultures of thyroid cells have been studied at the mRNA level. Autoantibodies to the thyrotropin (TSH) receptor from these patients, which had been initially characterized by their ability to stimulate adenylate cyclase and inhibit the binding of radiolabelled TSH to thyroid membrane preparations, were studied for their effects on thyroglobulin and thyroid peroxidase mRNA levels. Incubation of thyroid cells with TSH receptor autoantibodies from different Graves' disease patients for 48 h led to time- and dose-dependent increases in the levels of thyroid peroxidase and thyroglobulin mRNA in primary cultures of thyrocytes. The incomplete correlation between G protein-linked adenylate cyclase activation and thyroid mRNA elevation indicates the possibility of the involvement of alternative second messenger pathways in the regulation of thyroid cell function and differentiation.
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Affiliation(s)
- K S Collison
- Department of Medicine, King's College School of Medicine and Dentistry, London, UK
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Collison KS, Banga JP, Barnett PS, Huang GC, McGregor AM. Autoantibodies to the thyrotrophin receptor mimic thyrotrophin in stimulating both thyroglobulin and thyroid peroxidase mRNA transcription in human thyroid cells. Biochem Soc Trans 1990; 18:559-60. [PMID: 2276434 DOI: 10.1042/bst0180559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- K S Collison
- Department of Medicine, King's College Hospital School of Medicine, Denmark Hill, London, U.K
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Huang GC, Page MJ, Roberts AJ, Malik AN, Spence H, McGregor AM, Banga JP. Molecular cloning of a human thyrotropin receptor cDNA fragment. Use of highly degenerate, inosine containing primers derived from aligned amino acid sequences of a homologous family of glycoprotein hormone receptors. FEBS Lett 1990; 264:193-7. [PMID: 2358066 DOI: 10.1016/0014-5793(90)80246-f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Autoantibodies to the thyrotropin (TSH) hormone receptor (TSH-R) are present in the sera of patients with thyroid autoimmune disease which are pathogenetic leading to hyperthyroidism of Graves' disease. Considerable interest has been focused on the cloning of the human TSH-R, which has until very recently, proven exceedingly difficult due to the very low receptor level expression on thyroid cells. We have used polymerase chain reaction and highly degenerate, inosine containing oligonucleotides derived from sequence alignments of the transmembrane regions 2 and 7 of a number of G-binding protein receptors including the lutropin/choriogonadotropin (LH/CG) receptors to amplify various cDNAs from human thyroid cDNA. Sequencing analysis of 27 different clones revealed that they fall into eight different groups. The very recent publication of the complete nucleotide sequence of the human TSH-R revealed that one of the groups (GT1) containing seven clones which had been sequenced belong to the human TSH-receptor. The sequence of all 7 GT1 clones was identical and in complete concordance with transmembrane regions 2 and 7 of the published TSH-R sequence. Our results show that by designing oligonucleotides to common transmembrane regions of G-binding proteins where the primers are biased in their sequence to the LH/CG receptors it is possible to amplify the TSH-R receptor sequence.
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Affiliation(s)
- G C Huang
- Department of Medicine, King's College School of Medicine, London, UK
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Barnett PS, Banga JP, Watkins J, Huang GC, Gluckman DR, Page MJ, McGregor AM. Nucleotide sequence of the alternatively spliced human thyroid peroxidase cDNA, TPO-2. Nucleic Acids Res 1990; 18:670. [PMID: 2308857 PMCID: PMC333492 DOI: 10.1093/nar/18.3.670] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- P S Barnett
- Department of Medicine, King's College School of Medicine and Dentistry, London, UK
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50
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Gao YT, Shen PY, Wang BH, Lü SD, Huang GC, Ho LS. Controlled release effect of insecticide microcapsules and their results in common household insect pest control. J Microencapsul 1984; 1:307-15. [PMID: 6336530 DOI: 10.3109/02652048409031543] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Since 1978 we have prepared microencapsulated insecticides by complex coacervation and interfacial polymerization for household insect pest control, fenthion being the main core element. A series of tests have been conducted against mosquitoes (Culex pipiens quinquefasciatus), cockroaches (Periplaneta americana) and bedbugs (Cimex lectularius), and the results indicate that microencapsulation can prolong persistent effects by 2-12 times, enhance safety and subdue offensive odour. Furthermore, the production cost is comparatively low.
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Affiliation(s)
- Y T Gao
- Military Medical Research Institute of Fuchow Military District, Fujian, People's Republic of China
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