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Deng Q, He L, Xu F, Deng Q, Xu T, Jiang J, Hu Z, Yang J. Characterization of beta subunit variants of recombinant human chorionic gonadotrophin. Anal Biochem 2023; 668:115089. [PMID: 36858250 DOI: 10.1016/j.ab.2023.115089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/23/2023] [Accepted: 02/21/2023] [Indexed: 03/02/2023]
Abstract
Human chorionic gonadotropin (hCG), an endogenous glycoprotein hormone, has been widely used for the treatment of infertility and corpus luteum defect in women. The biological specificity of hCG is essentially determined by its beta (β-) subunit, whereas the alpha (α-) subunit is a common subunit shared among the gonadotropin family. In development of a therapeutic recombinant hCG, the purity analysis showed that the beta (β-) subunit has two variants, β1 and β2. Structural characterization using a combination of analytical techniques has demonstrated that β1-subunit is derived from non-glycosylation at Asn 13, whereas β2-subunit is a normal species with complete N-glycosylation at both Asn 13 and Asn 30. In vivo Bioactivity evaluation of the r-hCG fractions with various ratios of β1-and β2-subunits showed that incomplete glycosylation at Asn 13 potentially reduced the biological activity of r-hCG to promote uterus growth. Although hCG has a long history of medicinal use, this is the first report to identify the structural difference of hCG β-subunit variants, as well as to preliminary establish the structure-activity relationship of this variation. The obtained results also suggest the importance of variant characterization and necessary quality control of product variants during the development of recombinant protein therapeutics.
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Affiliation(s)
- Qinpei Deng
- Livzon MabPharm Inc., Zhuhai, Guangdong, China
| | - Lixiu He
- Livzon MabPharm Inc., Zhuhai, Guangdong, China
| | - Fangyan Xu
- Livzon MabPharm Inc., Zhuhai, Guangdong, China
| | | | - Tongze Xu
- Livzon MabPharm Inc., Zhuhai, Guangdong, China
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Ibeto L, Antonopoulos A, Grassi P, Pang PC, Panico M, Bobdiwala S, Al-Memar M, Davis P, Davis M, Norman Taylor J, Almeida P, Johnson MR, Harvey R, Bourne T, Seckl M, Clark G, Haslam SM, Dell A. Insights into the hyperglycosylation of human chorionic gonadotropin revealed by glycomics analysis. PLoS One 2020; 15:e0228507. [PMID: 32045434 PMCID: PMC7012436 DOI: 10.1371/journal.pone.0228507] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 01/16/2020] [Indexed: 12/13/2022] Open
Abstract
Human chorionic gonadotropin (hCG) is a glycoprotein hormone that is essential for the maintenance of pregnancy. Glycosylation of hCG is known to be essential for its biological activity. "Hyperglycosylated" variants secreted during early pregnancy have been proposed to be involved in initial implantation of the embryo and as a potential diagnostic marker for gestational diseases. However, what constitutes "hyperglycosylation" is not yet fully understood. In this study, we perform comparative N-glycomic analysis of hCG expressed in the same individuals during early and late pregnancy to help provide new insights into hCG function, reveal new targets for diagnostics and clarify the identity of hyperglycosylated hCG. hCG was isolated in urine collected from women at 7 weeks and 20 weeks' gestation. hCG was also isolated in urine from women diagnosed with gestational trophoblastic disease (GTD). We used glycomics methodologies including matrix assisted laser desorption/ionisation-time of flight (MALDI-TOF) mass spectrometry (MS) and MS/MS methods to characterise the N-glycans associated with hCG purified from the individual samples. The structures identified on the early pregnancy (EP-hCG) and late pregnancy (LP-hCG) samples corresponded to mono-, bi-, tri-, and tetra-antennary N-glycans. A novel finding was the presence of substantial amounts of bisected type N-glycans in pregnancy hCG samples, which were present at much lower levels in GTD samples. A second novel observation was the presence of abundant LewisX antigens on the bisected N-glycans. GTD-hCG had fewer glycoforms which constituted a subset of those found in normal pregnancy. When compared to EP-hCG, GTD-hCG samples had decreased signals for tri- and tetra-antennary N-glycans. In terms of terminal epitopes, GTD-hCG had increased signals for sialylated structures, while LewisX antigens were of very minor abundance. hCG carries the same N-glycans throughout pregnancy but in different proportions. The N-glycan repertoire is more diverse than previously reported. Bisected and LewisX structures are potential targets for diagnostics. hCG isolated from pregnancy urine inhibits NK cell cytotoxicity in vitro at nanomolar levels and bisected type glycans have previously been implicated in the suppression of NK cell cytotoxicity, suggesting that hCG-related bisected type N-glycans may directly suppress NK cell cytotoxicity.
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Affiliation(s)
- Linda Ibeto
- Department of Life Sciences, Imperial College London, London, United Kingdom
- Academic Department of Obstetrics and Gynaecology, Chelsea and Westminster Hospital, London, United Kingdom
| | | | - Paola Grassi
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Poh-Choo Pang
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Maria Panico
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Shabnam Bobdiwala
- Tommys' National Centre for Miscarriage Research, Queen Charlottes' & Chelsea Hospital, Imperial College, London, United Kingdom
| | - Maya Al-Memar
- Tommys' National Centre for Miscarriage Research, Queen Charlottes' & Chelsea Hospital, Imperial College, London, United Kingdom
| | - Paul Davis
- Mologic LTD, Bedford Technology Park, Bedfordshire, United Kingdom
| | - Mark Davis
- Mologic LTD, Bedford Technology Park, Bedfordshire, United Kingdom
| | - Julian Norman Taylor
- Academic Department of Obstetrics and Gynaecology, Chelsea and Westminster Hospital, London, United Kingdom
| | - Paula Almeida
- Academic Department of Obstetrics and Gynaecology, Chelsea and Westminster Hospital, London, United Kingdom
| | - Mark R. Johnson
- Academic Department of Obstetrics and Gynaecology, Chelsea and Westminster Hospital, London, United Kingdom
| | - Richard Harvey
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Tom Bourne
- Tommys' National Centre for Miscarriage Research, Queen Charlottes' & Chelsea Hospital, Imperial College, London, United Kingdom
| | - Michael Seckl
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Gary Clark
- Department of Obstetrics, Gynaecology and Women's Health, University of Missouri, Columbia, Missouri, United States of America
| | - Stuart M. Haslam
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Anne Dell
- Department of Life Sciences, Imperial College London, London, United Kingdom
- * E-mail:
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3
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Maternal Urine Screening for Down Syndrome: Past Studies and Future Perspectives. JOURNAL OF FETAL MEDICINE 2016. [DOI: 10.1007/s40556-016-0107-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Iles RK, Shahpari ME, Cuckle H, Butler SA. Direct and rapid mass spectral fingerprinting of maternal urine for the detection of Down syndrome pregnancy. Clin Proteomics 2015; 12:9. [PMID: 25878568 PMCID: PMC4389308 DOI: 10.1186/s12014-015-9082-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 03/09/2015] [Indexed: 01/31/2023] Open
Abstract
Background The established methods of antenatal screening for Down syndrome are based on immunoassay for a panel of maternal serum biomarkers together with ultrasound measures. Recently, genetic analysis of maternal plasma cell free (cf) DNA has begun to be used but has a number of limitations including excessive turn-around time and cost. We aimed to develop an alternative method based on urinalysis that is simple, affordable and accurate. Method 101 maternal urine samples sampled at 12–17 weeks gestation were taken from an archival collection of 2567 spot urines collected from women attending a prenatal screening clinic. 18 pregnancies in this set subsequently proved to be Down pregnancies. Samples were either neat urine or diluted between 10 to 1000 fold in dH2O and subjected to matrix assisted laser desorption ionization (MALDI), time of flight (ToF) mass spectrometry (MS). Data profiles were examined in the region 6,000 to 14,000 m/z. Spectral data was normalised and quantitative characteristics of the profile were compared between Down and controls. Results In Down cases there were additional spectral profile peaks at 11,000-12,000 m/z and a corresponding reduction in intensity at 6,000-8,000 m/z. The ratio of the normalised values at these two ranges completely separated the 8 Down syndrome from the 39 controls at 12–14 weeks. Discrimination was poorer at 15–17 weeks where 3 of the 10 Down syndrome cases had values within the normal range. Conclusions Direct MALDI ToF mass spectral profiling of maternal urinary has the potential for an affordable, simple, accurate and rapid alternative to current Down syndrome screening protocols.
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Affiliation(s)
- Ray K Iles
- MAP Diagnostics Ltd, The BioPark, Broadwater Road, Welwyn Garden City, Hertfordshire, AL7 3AX UK
| | - Maryam E Shahpari
- MAP Diagnostics Ltd, The BioPark, Broadwater Road, Welwyn Garden City, Hertfordshire, AL7 3AX UK ; Middlesex University, Hendon, London, UK
| | | | - Stephen A Butler
- MAP Diagnostics Ltd, The BioPark, Broadwater Road, Welwyn Garden City, Hertfordshire, AL7 3AX UK ; Middlesex University, Hendon, London, UK
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Aldaz-Carroll L, Richon S, Dangles-Marie V, Cocquebert M, Fournier T, Troalen F, Stevens D, Guery B, Hersant AM, Guibourdenche J, Nordor A, Pecking A, Bellet D. Specific detection of type II human chorionic gonadotropin beta subunit produced by trophoblastic and neoplastic cells. Clin Chim Acta 2015; 444:92-100. [PMID: 25681647 DOI: 10.1016/j.cca.2015.02.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 02/01/2015] [Accepted: 02/03/2015] [Indexed: 10/24/2022]
Abstract
BACKGROUND The sequence of the beta-subunit of human chorionic gonadotropin (hCGβ) varies depending on whether hCGβ is encoded by type I or type II genes. Type II genes are upregulated in trophoblast and cancer but hCGβ can be detected in the serum of nonpregnant women and healthy individuals. We aimed to determine whether monoclonal antibody (mAb) FBT11-II specifically detects hCGβ encoded by type II genes (type II hCGβ). METHODS Competitive inhibition assays with synthetic peptides, immunocytochemical and immunohistochemical studies, type II hCGβ dosing immunoassays and sequencing of CGB genes were performed. RESULTS Competitive inhibition assays determined that mAb FBT11-II recognizes the type II hCGβ derived peptide. CGB mRNA sequencing of JEG-3 (trophoblastic) and T24 (bladder) cell lines confirmed that JEG-3 expresses type II genes while T24 expresses exclusively type I. FBT11-II only recognizes JEG-expressed hCGβ. Placenta immunohistochemical studies confirmed that type II hCGβ expression is restricted to the syncytiotrophoblast. Immunoassays detected type II hCGβ in serum of patients with either nontrophoblastic cancers or fetal Down syndrome. CONCLUSION Type II gene expression can be detected using FBT11-II. This specific recognition could improve the clinical usefulness of assays aimed at either managing aggressive tumors or screening for Down syndrome.
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Affiliation(s)
- L Aldaz-Carroll
- Université Paris Descartes, Sorbonne Paris Cité, Unité de Technologies Chimiques et Biologiques pour la Santé, Faculté de Pharmacie, 4, avenue de l'Observatoire, 75006 Paris France; Ecole Nationale Supérieure de Chimie de Paris, Chimie Paristech, 11, rue Pierre et Marie Curie, 75005 Paris France; CNRS, UMR8258, 4, avenue de l'Observatoire, 75006 Paris France; INSERM U1022, 4, avenue de l'Observatoire, 75006 Paris France.
| | - S Richon
- Université Paris Descartes, Sorbonne Paris Cité, Institut Médicament Toxicologie Chimie Environnement (IMTCE), 4, avenue de l'Observatoire, 75006 Paris France.
| | - V Dangles-Marie
- Université Paris Descartes, Sorbonne Paris Cité, 4, avenue de l'Observatoire, 75006 Paris France; Centre de recherche Institut Curie, Recherche Translationnelle, 26 rue d'Ulm, 75005 Paris France.
| | - M Cocquebert
- Université Paris Descartes, Sorbonne Paris Cité, UMR-S 1139, 4, avenue de l'Observatoire, 75006 Paris France; INSERM U1139, 4, avenue de l'Observatoire, 75006 Paris France; PremUP fundation, Maternité de Port Royal, 53 avenue de l'Observatoire, 75014 Paris France.
| | - T Fournier
- Université Paris Descartes, Sorbonne Paris Cité, UMR-S 1139, 4, avenue de l'Observatoire, 75006 Paris France; INSERM U1139, 4, avenue de l'Observatoire, 75006 Paris France; PremUP fundation, Maternité de Port Royal, 53 avenue de l'Observatoire, 75014 Paris France.
| | - F Troalen
- Institut de Cancérologie Gustave-Roussy, Département de Biologie et Pathologie Médicales, 114 rue Édouard-Vaillant, 94805 Villejuif Cedex, France.
| | - D Stevens
- Institut Curie, Hôpital René Huguenin, Département de santé publique, 35, rue Dailly, 92210 Saint Cloud, France.
| | - B Guery
- Institut Curie, Hôpital René Huguenin, Laboratoire d'Oncobiologie, Département de Biopathologie, 35, rue Dailly, 92210 Saint Cloud, France.
| | - A-M Hersant
- Institut Curie, Hôpital René Huguenin, Laboratoire d'Oncobiologie, Département de Biopathologie, 35, rue Dailly, 92210 Saint Cloud, France.
| | - J Guibourdenche
- Université Paris Descartes, Sorbonne Paris Cité, UMR-S 1139, 4, avenue de l'Observatoire, 75006 Paris France; INSERM U1139, 4, avenue de l'Observatoire, 75006 Paris France; PremUP fundation, Maternité de Port Royal, 53 avenue de l'Observatoire, 75014 Paris France.
| | - A Nordor
- Université Paris Descartes, Sorbonne Paris Cité, 4, avenue de l'Observatoire, 75006 Paris France; Centre de recherche Institut Curie, Recherche Translationnelle, 26 rue d'Ulm, 75005 Paris France.
| | - A Pecking
- Institut Curie, Hôpital René Huguenin, Laboratoire d'Oncobiologie, Département de Biopathologie, 35, rue Dailly, 92210 Saint Cloud, France.
| | - D Bellet
- Université Paris Descartes, Sorbonne Paris Cité, Unité de Technologies Chimiques et Biologiques pour la Santé, Faculté de Pharmacie, 4, avenue de l'Observatoire, 75006 Paris France; Ecole Nationale Supérieure de Chimie de Paris, Chimie Paristech, 11, rue Pierre et Marie Curie, 75005 Paris France; CNRS, UMR8258, 4, avenue de l'Observatoire, 75006 Paris France; INSERM U1022, 4, avenue de l'Observatoire, 75006 Paris France; Institut Curie, Hôpital René Huguenin, Laboratoire d'Oncobiologie, Département de Biopathologie, 35, rue Dailly, 92210 Saint Cloud, France.
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6
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Direct analysis of hCGβcf glycosylation in normal and aberrant pregnancy by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Int J Mol Sci 2014; 15:10067-82. [PMID: 24905406 PMCID: PMC4100140 DOI: 10.3390/ijms150610067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 05/20/2014] [Accepted: 05/21/2014] [Indexed: 11/18/2022] Open
Abstract
The analysis of human chorionic gonadotropin (hCG) in clinical chemistry laboratories by specific immunoassay is well established. However, changes in glycosylation are not as easily assayed and yet alterations in hCG glycosylation is associated with abnormal pregnancy. hCGβ-core fragment (hCGβcf) was isolated from the urine of women, pregnant with normal, molar and hyperemesis gravidarum pregnancies. Each sample was subjected to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) analysis following dithiothreitol (DTT) reduction and fingerprint spectra of peptide hCGβ 6–40 were analyzed. Samples were variably glycosylated, where most structures were small, core and largely mono-antennary. Larger single bi-antennary and mixtures of larger mono-antennary and bi-antennary moieties were also observed in some samples. Larger glycoforms were more abundant in the abnormal pregnancies and tri-antennary carbohydrate moieties were only observed in the samples from molar and hyperemesis gravidarum pregnancies. Given that such spectral profiling differences may be characteristic, development of small sample preparation for mass spectral analysis of hCG may lead to a simpler and faster approach to glycostructural analysis and potentially a novel clinical diagnostic test.
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Blanchard V, Gadkari RA, George AVE, Roy S, Gerwig GJ, Leeflang BR, Dighe RR, Boelens R, Kamerling JP. High-level expression of biologically active glycoprotein hormones in Pichia pastoris strains--selection of strain GS115, and not X-33, for the production of biologically active N-glycosylated 15N-labeled phCG. Glycoconj J 2008; 25:245-57. [PMID: 18274893 PMCID: PMC2668595 DOI: 10.1007/s10719-007-9082-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Revised: 08/30/2007] [Accepted: 10/19/2007] [Indexed: 11/29/2022]
Abstract
The methylotrophic yeast Pichia pastoris is widely used for the production of recombinant glycoproteins. With the aim to generate biologically active 15N-labeled glycohormones for conformational studies focused on the unravelling of the NMR structures in solution, the P. pastoris strains GS115 and X-33 were explored for the expression of human chorionic gonadotropin (phCG) and human follicle-stimulating hormone (phFSH). In agreement with recent investigations on the N-glycosylation of phCG, produced in P. pastoris GS115, using ammonia/glycerol-methanol as nitrogen/carbon sources, the N-glycosylation pattern of phCG, synthesized using NH4Cl/glucose–glycerol–methanol, comprised neutral and charged, phosphorylated high-mannose-type N-glycans (Man8–15GlcNAc2). However, the changed culturing protocol led to much higher amounts of glycoprotein material, which is of importance for an economical realistic approach of the aimed NMR research. In the context of these studies, attention was also paid to the site specific N-glycosylation in phCG produced in P. pastoris GS115. In contrast to the rather simple N-glycosylation pattern of phCG expressed in the GS115 strain, phCG and phFSH expressed in the X-33 strain revealed, besides neutral high-mannose-type N-glycans, also high concentrations of neutral hypermannose-type N-glycans (Manup-to-30GlcNAc2). The latter finding made the X-33 strain not very suitable for generating 15N-labeled material. Therefore, 15N-phCG was expressed in the GS115 strain using the new optimized protocol. The 15N-enrichment was evaluated by 15N-HSQC NMR spectroscopy and GLC-EI/MS. Circular dichroism studies indicated that 15N-phCG/GS115 had the same folding as urinary hCG. Furthermore, 15N-phCG/GS115 was found to be similar to the unlabeled protein in every respect as judged by radioimmunoassay, radioreceptor assays, and in vitro bioassays.
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Affiliation(s)
- Véronique Blanchard
- Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, Padualaan 8, NL-3584 CH, Utrecht, The Netherlands
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Kicman AT, Parkin MC, Iles RK. An introduction to mass spectrometry based proteomics-detection and characterization of gonadotropins and related molecules. Mol Cell Endocrinol 2007; 260-262:212-27. [PMID: 17097803 DOI: 10.1016/j.mce.2006.02.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Accepted: 02/05/2006] [Indexed: 11/28/2022]
Abstract
This review introduces fundamental aspects of mass spectrometry (MS) based proteomics and illustrates how MS is an effective tool for the analysis of glycoprotein hormones. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) and electrospray ionization (ESI) MS are complementary approaches that have been applied for the analysis of gonadotropins, e.g. to characterize differences in the oligosaccharide distribution of commercial human chorionic gonadotropin preparations, for isolated nicked beta-subunit, and identification of a metabolite of placental transforming growth factor in pharmaceutical hCG preparations. Immunoaffinity trapping and concentration of digested sample extract prior to MS analysis confers analytical sensitivity akin to immunoassay. A desirable objective would be to develop for clinical purposes a rapid procedure for MS detection and characterization of gonadotropins. Refinement of on-target immobilization and digestion for subsequent ionization by MALDI may eventually help to provide this capability. The advent of hybrid mass spectrometers will further advance the characterization of these complex molecules.
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Affiliation(s)
- Andrew T Kicman
- Department of Forensic Science & Drug Monitoring (Drug Control Centre), Kings College London, 150 Stamford Street, London SE1 9NH, UK.
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Kelly LS, Birken S, Puett D. Determination of hyperglycosylated human chorionic gonadotropin produced by malignant gestational trophoblastic neoplasias and male germ cell tumors using a lectin-based immunoassay and surface plasmon resonance. Mol Cell Endocrinol 2007; 260-262:33-9. [PMID: 17081681 PMCID: PMC1847626 DOI: 10.1016/j.mce.2006.05.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Accepted: 05/12/2006] [Indexed: 11/16/2022]
Abstract
The ability to reliably detect aberrant glycosylation of human chorionic gonadotropin (hCG) may have profound implications for the diagnosis and monitoring of malignant gestational trophoblastic neoplasia, germ cell tumors, other malignancies, and pregnancy complications. To become a clinically useful assay, however, this discrimination of glycoforms should be possible on minimally treated biological specimens. Towards this end, we have developed a lectin-based sandwich-type immunoassay to compare the glycosylation patterns of hCG among urine specimens from patients presenting with a normal pregnancy, invasive mole, choriocarcinoma, and male germ cell tumors using carbohydrate-free antibody fragments as capture reagents and a panel of eight lectins, five recognizing neutral sugars and three recognizing sialic acid. There was no significant difference in the binding of any of the lectins to hCG in the urine of women over the gestational range of 6-38 weeks. Three lectins, however, exhibited differential binding to urinary hCG derived from these normal pregnant controls and that from patients with malignant forms of gestational trophoblastic disease and male germ cell tumors. Galanthus nivalis agglutinin and Maackia amurensis lectin, which bind terminal mannose and alpha(2-3)sialic acid, respectively, preferentially bound pregnancy-derived hCG, whereas the lectin, wheat germ agglutinin, which binds sialic acid and beta(1-4)N-acetylglucosamine, exhibited decreased binding to pregnancy-derived hCG compared to that from patients with male germ cell tumors and malignant gestational trophoblastic neoplasia. The differential binding observed with these three promising lectins is most encouraging and warrants further examination. The experimental paradigm also holds promise for the development of comparable assays for other glycosylated tumor markers.
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Affiliation(s)
- Lisa S Kelly
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
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Stenman UH, Tiitinen A, Alfthan H, Valmu L. The classification, functions and clinical use of different isoforms of HCG. Hum Reprod Update 2006; 12:769-84. [PMID: 16877746 DOI: 10.1093/humupd/dml029] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
HCG is composed of two subunits, HCGalpha and HCGbeta. During early pregnancy, HCG stimulates progesterone production in the corpus luteum, and injection of HCG is widely used to induce ovulation in assisted reproduction treatment (ART). Under experimental conditions, the free subunits have been shown to exert functions other than those of HCG, but the relevance of these remains to be determined. Intact HCG, free subunits and degraded forms of these occur in biological fluids, and determinations of these are important for diagnosis and monitoring of pregnancy, pregnancy-related disorders and several types of cancer. Development of optimal methods for the various forms has been hampered by lack of appropriate standards and expression of the concentrations of the various forms in units that are not comparable. Furthermore, the nomenclature for HCG assays is confusing and in some cases misleading. These problems can now be solved; a uniform nomenclature has been established, and new standards are available for HCG, its subunits HCGalpha and HCGbeta, the partially degraded or nicked forms of HCG and HCGbeta, and the beta-core fragment. This review describes the biochemical and biological background for the clinical use of determinations of various forms of HCG. The clinical use of HCG and studies on HCG vaccines are briefly reviewed.
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Affiliation(s)
- Ulf-Håkan Stenman
- Department of Clinical Chemistry, Helsinki University Central Hospital, Helsinki, Finland.
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11
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Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update covering the period 1999-2000. MASS SPECTROMETRY REVIEWS 2006; 25:595-662. [PMID: 16642463 DOI: 10.1002/mas.20080] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
This review describes the use of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry for the analysis of carbohydrates and glycoconjugates and continues coverage of the field from the previous review published in 1999 (D. J. Harvey, Matrix-assisted laser desorption/ionization mass spectrometry of carbohydrates, 1999, Mass Spectrom Rev, 18:349-451) for the period 1999-2000. As MALDI mass spectrometry is acquiring the status of a mature technique in this field, there has been a greater emphasis on applications rather than to method development as opposed to the previous review. The present review covers applications to plant-derived carbohydrates, N- and O-linked glycans from glycoproteins, glycated proteins, mucins, glycosaminoglycans, bacterial glycolipids, glycosphingolipids, glycoglycerolipids and related compounds, and glycosides. Applications of MALDI mass spectrometry to the study of enzymes acting on carbohydrates (glycosyltransferases and glycosidases) and to the synthesis of carbohydrates, are also covered.
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Affiliation(s)
- David J Harvey
- Department of Biochemistry, Oxford Glycobiology Institute, University of Oxford, Oxford OX1 3QU, United Kingdom.
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12
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Abstract
Glycosylation is a common post-translational modification to cell surface and extracellular matrix (ECM) proteins as well as to lipids. As a result, cells carry a dense coat of carbohydrates on their surfaces that mediates a wide variety of cell-cell and cell-matrix interactions that are crucial to development and function. Because of the historical difficulties with the analysis of complex carbohydrate structures, a detailed understanding of their roles in biology has been slow to develop. Just as mass spectrometry has proven to be the core technology behind proteomics, it stands to play a similar role in the study of functional implications of carbohydrate expression, known as glycomics. This review summarizes the state of knowledge for the mass spectrometric analysis of oligosaccharides with regard to neutral, sialylated, and sulfated compound classes. Mass spectrometric techniques for the ionization and fragmentation of oligosaccharides are discussed so as to give the reader the background to make informed decisions to solve structure-activity relations in glycomics.
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Affiliation(s)
- Joseph Zaia
- Department of Biochemistry, Boston University School of Medicine, 715 Albany St., R-806, Boston, Massachusetts 02118, USA.
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Neubert H, Jacoby ES, Bansal SS, Iles RK, Cowan DA, Kicman AT. Enhanced affinity capture MALDI-TOF MS: orientation of an immunoglobulin G using recombinant protein G. Anal Chem 2002; 74:3677-83. [PMID: 12175153 DOI: 10.1021/ac025558z] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although immobilization of antigen-specific immunoglobulins onto matrix-assisted laser desorption/ionization (MALDI) targets allows the specific detection and enrichment of an antigen from complex biological fluids, the process of antibody immobilization is not optimal. The principal reason is that the antibody can bind to the template in various orientations, many of which block antigen recognition. An affinity capture MALDI mass spectrometry methodology was developed by covalently immobilizing an Fc receptor (recombinant protein G) onto MALDI gold targets for the purpose of orientating an immunoglobulin G, with the Fab domains pointing away from the target surface. The pregnancy and cancer marker, human chorionic gonadotropin beta core fragment (hCGbetacf), was our chosen test substance. To optimize the methodology, different surface densities of protein G and immunoglobulin were achieved by employing varying concentrations for immobilization. Captured amounts of hCGbetacf were compared using an external standard (cytochrome c). Orientation of immunoglobulin resulted in an approximately 3-fold increase in MALDI signal compared to using randomly immobilized antibody. Higher antibody concentrations resulted in diminished MALDI signals, which were explained by steric hindrance. Purification and enrichment of hCGbetacf was achieved from a test solution containing contaminant peptides and proteins using oriented immunoglobulins on-target.
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Affiliation(s)
- Hendrik Neubert
- Drug Control Centre and Department of Pharmacy, King's College London, United Kingdom
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Current literature in mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2001; 36:347-354. [PMID: 11312528 DOI: 10.1002/jms.90] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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