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Chrostek L, Gindzieńska-Sieśkiewicz E, Gruszewska E, Kowal-Bielecka O, Cylwik B. Transferrin isoforms analysis by capillary electrophoresis in systemic lupus erythematosus and systemic sclerosis. Scandinavian Journal of Clinical and Laboratory Investigation 2020; 80:567-570. [PMID: 32820969 DOI: 10.1080/00365513.2020.1804611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) are a diseases in which disturbances in plasma proteins glycosylation exist. The aim of the study was to compare the serum profile of transferrin isoforms between SLE and SSc. The study was carried out in 38 patients with SLE and 43 patients with SSc. Transferrin isoforms were analyzed by capillary electrophoresis method. Among the transferrin isoforms only the level of pentasialotransferrin in SLE patients was significantly higher than in SSc patients (p = .014). The median concentrations of trisialotransferrin and pentasialotransferrin were significantly lower in SLE patients (p < .001, p = .042; respectively) and SSc (p = .001, p < .001; respectively) than in the healthy subjects. In contrast, the level of tetrasialotransferrin manifested significant increase in comparison to the controls (p < .001 for all comparisons). The serum profile of transferrin isoforms alters in SLE and SSc but only level of pentasialotransferrin differs between SLE and SSc patients. We confirm that the serum profile of transferrin isoforms in SLE and SSc is unique to these diseases.
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Affiliation(s)
- Lech Chrostek
- Department of Biochemical Diagnostics, Medical University of Bialystok, Bialystok, Poland
| | | | - Ewa Gruszewska
- Department of Biochemical Diagnostics, Medical University of Bialystok, Bialystok, Poland
| | - Otylia Kowal-Bielecka
- Department of Rheumatology and Internal Medicine, Medical University of Bialystok, Bialystok, Poland
| | - Bogdan Cylwik
- Department of Pediatric Laboratory Diagnostics, Medical University of Bialystok, Bialystok, Poland
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Tabasum S, Noreen A, Kanwal A, Zuber M, Anjum MN, Zia KM. Glycoproteins functionalized natural and synthetic polymers for prospective biomedical applications: A review. Int J Biol Macromol 2017; 98:748-776. [PMID: 28111295 DOI: 10.1016/j.ijbiomac.2017.01.078] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 01/05/2017] [Accepted: 01/16/2017] [Indexed: 02/06/2023]
Abstract
Glycoproteins have multidimensional properties such as biodegradability, biocompatibility, non-toxicity, antimicrobial and adsorption properties; therefore, they have wide range of applications. They are blended with different polymers such as chitosan, carboxymethyl cellulose (CMC), polyvinyl pyrrolidone (PVP), polycaprolactone (PCL), heparin, polystyrene fluorescent nanoparticles (PS-NPs) and carboxyl pullulan (PC) to improve their properties like thermal stability, mechanical properties, resistance to pH, chemical stability and toughness. Considering the versatile charateristics of glycoprotein based polymers, this review sheds light on synthesis and characterization of blends and composites of glycoproteins, with natural and synthetic polymers and their potential applications in biomedical field such as drug delivery system, insulin delivery, antimicrobial wound dressing uses, targeting of cancer cells, development of anticancer vaccines, development of new biopolymers, glycoproteome research, food product and detection of dengue glycoproteins. All the technical scientific issues have been addressed; highlighting the recent advancement.
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Affiliation(s)
- Shazia Tabasum
- Institute of Chemistry, Government College University, Faisalabad 38030, Pakistan
| | - Aqdas Noreen
- Institute of Chemistry, Government College University, Faisalabad 38030, Pakistan
| | - Arooj Kanwal
- Institute of Chemistry, Government College University, Faisalabad 38030, Pakistan
| | - Mohammad Zuber
- Institute of Chemistry, Government College University, Faisalabad 38030, Pakistan
| | | | - Khalid Mahmood Zia
- Institute of Chemistry, Government College University, Faisalabad 38030, Pakistan.
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3
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Denecke J, Kranz C, von Kleist-Retzow JC, Bosse K, Herkenrath P, Debus O, Harms E, Marquardt T. Congenital disorder of glycosylation type Id: clinical phenotype, molecular analysis, prenatal diagnosis, and glycosylation of fetal proteins. Pediatr Res 2005; 58:248-53. [PMID: 16006436 DOI: 10.1203/01.pdr.0000169963.94378.b6] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Congenital disorder of glycosylation type Id is an inherited glycosylation disorder based on a defect of the first mannosyltransferase involved in N-glycan biosynthesis inside the endoplasmic reticulum. Only one patient with this disease has been described until now. In this article, a second patient and an affected fetus are described. The patient showed abnormal glycosylation of several plasma proteins as demonstrated by isoelectric focusing and Western blot. Lipid-linked oligosaccharides in the endoplasmic reticulum, reflecting early N-glycan assembly, revealed an accumulation of immature Man(5)GlcNAc(2)-glycans in fibroblasts of the patient. Chorion cells of the affected fetus showed the same characteristic lipid-linked oligosaccharides pattern. However, the fetus had a normal glycosylation of several plasma proteins. Some fetal glycoproteins are known to be derived from the mother, but even glycoproteins that do not cross the placenta were normally glycosylated in the affected fetus. Maternal or placental factors that partially compensate for the glycosylation defect in the fetal stage must be proposed and may be relevant for the therapy of these disorders in the future.
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Affiliation(s)
- Jonas Denecke
- Department of Pediatrics, University Hospital of Münster, 48149 Münster, Germany.
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4
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Wu Y, Sakamoto H, Kanenishi K, Li J, Khatun R, Hata T. Transferrin microheterogeneity in pregnancies with preeclampsia. Clin Chim Acta 2003; 332:103-10. [PMID: 12763287 DOI: 10.1016/s0009-8981(03)00134-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND It has been reported that concentrations of serum transferrin (Tf) and its highly sialylated subfraction increase in normal pregnancy. This study investigated changes in the concentrations of serum transferrin and its subfractions in preeclampsia. METHODS The serum concentration of transferrin was determined by a standard turbidimetric assay and microheterogeneous transferrin subgroups (low sialylated, 4-sialo and highly sialylated transferrins) were assessed by crossed immuno-isoelectric focusing. RESULTS Compared to normal pregnancy, the concentrations of total, 4-sialo and highly sialylated transferrins decreased by 27%, 16% and 38%, respectively, in severe preeclampsia, while these values did not significantly decrease in mild preeclampsia. The concentration of low sialylated transferrin involving 2-sialo- and 3-sialo-transferrins significantly decreased both in mild and severe preeclampsia, the value in severe preeclampsia was even significantly lower than that in nonpregnant women. The serum concentrations of total and highly sialylated transferrins in preeclampsia were correlated positively with infant birth weights (r=0.587 and r=0.645, respectively). CONCLUSIONS The serum concentrations of total and highly sialylated transferrins in severe preeclampsia decrease significantly. This might have a negative impact on intrauterine growth. Additionally, the serum low sialylated transferrin decreases more sensitively in preeclampsia, although the concentration is low even in normal pregnancy.
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Affiliation(s)
- YangHong Wu
- Department of Inflammation Pathology, Kagawa Medical University, 1750-1, Miki-cho, Kita-gun, Kagawa 761-0793, Japan
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5
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Trout AL, Prasad R, Coffin D, DiMartini A, Lane T, Blessum C, Khatter N, Landers JP. Direct capillary electrophoretic detection of carbohydrate-deficient transferrin in neat serum. Electrophoresis 2000; 21:2376-83. [PMID: 10939448 DOI: 10.1002/1522-2683(20000701)21:12<2376::aid-elps2376>3.0.co;2-p] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Transferrin, an iron transport protein found in serum and cerebrospinal fluid, is known to be microheterogeneous with respect to its carbohydrate and sialic acid content. The forms of transferrin deficient in sialic acid and/or carbohydrate, termed carbohydrate-deficient transferrin (CDT), have been of clinical interest for almost two decades as a result of the initial finding that elevated CDT concentrations are associated with chronic, excessive alcohol abuse. We demonstrate the utility of capillary electrophoresis for examining the CDT sialoform profile via the direct electrophoresis of serum. The need for negligible preelectrophoresis sample preparation and absence of postelectrophoresis processing dramatically decreases analysis time compared to slab gel-based separations. Using a fluorocarbon-coated capillary containing a hydroxyethyl cellulose/borate buffer, the high resolution separation of serum components is effected in less than 30 min. Under these conditions, the beta region proteins (including transferrin) are well resolved from the alpha-2 and gamma zone proteins in a window where the individual transferrin sialoforms can be detected. The usefulness of this method is demonstrated with the electrophoresis of serum from subjects known to be either non-alcoholic and alcoholic.
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Affiliation(s)
- A L Trout
- Department of Chemistry, University of Pittsburgh, PA, USA
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6
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Giordano BC, Muza M, Trout A, Landers JP. Dynamically-coated capillaries allow for capillary electrophoretic resolution of transferrin sialoforms via direct analysis of human serum. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2000; 742:79-89. [PMID: 10892586 DOI: 10.1016/s0378-4347(00)00128-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Transferrin sialoforms with fewer than three sialic acid residues (carbohydrate deficient transferrin; CDT) have been implicated as a marker of certain liver pathologies. Transferrin sialoforms in human sera from alcoholic and non-alcoholic patients was analyzed by capillary electrophoresis (CE) using diaminobutane (DAB) to dynamically-coat the capillary wall to minimize protein-wall interactions. Using a DAB concentration of 3 mM, transferrin sialoforms were adequately resolved to allow for direct detection of CDT without extensive treatment of the sera. Serum immunoglobulins, which migrated close to the CDT region, were removed via subtraction with protein A, enhancing the detection of CDT. The reproducibility of sialoform separation in dynamically-coated capillaries was found to be acceptable with run-to-run relative standard deviation values of 0.15% for a sample on a given day and 0.29+/-0.06% for four samples day-to-day. These results suggest that dynamic-coating approaches may provide a simple alternative to the use of covalently-coated capillaries for the CE separation of complex samples.
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Affiliation(s)
- B C Giordano
- Department of Chemistry, University of Virginia, Charlottesville 22901, USA
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7
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D'Andrea G, Gemini L, D'Alessandro AM, Oratore A. Deglycosylation of hen ovotransferrin under mild conditions: effect on the immunoreactivity and biological activity. Glycobiology 1999; 9:v-viii. [PMID: 10523079 DOI: 10.1093/oxfordjournals.glycob.a018871] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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8
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Cotton F, Adler M, Dumon J, Boeynaems JM, Gulbis B. A simple method for carbohydrate-deficient transferrin measurements in patients with alcohol abuse and hepato-gastrointestinal diseases. Ann Clin Biochem 1998; 35 ( Pt 2):268-73. [PMID: 9547899 DOI: 10.1177/000456329803500211] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Carbohydrate-deficient transferrin (CDT) is known to be increased in alcohol abuse. Several methods were developed for its measurement (e.g. isoelectric focusing with Western blotting or immunofixation, anion-exchange chromatography followed by immunoassays). We describe a greatly simplified isoelectric focusing technique which does not require immunofixation. CDT results obtained with this method were compared to other biological markers of alcohol abuse, i.e. mean corpuscular volume (MCV), aspartate aminotransferase (ASAT) and gamma-glutamyl-transferase (GGT), in 55 patients distributed in three groups (i.e. healthy control subjects, control patients suffering from various hepato-gastrointestinal diseases and alcohol abusing patients). Sensitivity and specificity were 33-89%, 61-57%, 89-49% and 83-100% for MCV, ASAT, GGT and CDT, respectively. We conclude that our method is highly suitable for routine clinical use.
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Affiliation(s)
- F Cotton
- Department of Clinical Chemistry, Hôpital Erasme Université Libre de Bruxelles, Belgium
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9
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Pierpaoli W, Lesnikov VA, Lesnikova MP, Arrighi S, Bardotti A. Unresponsiveness to human leukocytes in immunosuppressed mice by combined donor-derived human transferrin and antigens. Transpl Immunol 1996; 4:301-8. [PMID: 8972560 DOI: 10.1016/s0966-3274(96)80051-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Previous work on the facilitation of xenogeneic and allogeneic bone marrow engraftment in irradiated mice and dogs with transferrins allowed the development of a model for induction of an apparently durable state of immunological unresponsiveness or 'tolerance' in chemically immunosuppressed mice. The system is based on the simultaneous and combined administration of donor-derived cell antigens, namely human leukocytes, and specific donor-derived or plasma pool human transferrin into BALB/c or C57BL/6 mice previously treated with prednisolone and cyclophosphamide on day 0 and day 1 of the experiment. A properly timed presentation of both donor-specific or plasma pool transferrin and leukocyte antigens into the mice on day 3 and day 16 of the experiment, in the course of initial restoration of their lymphohaemopoietic tissues and cells after severe immunosuppression, results 1-3 months later, in their inability to 'recognize' human donor lymphocytes and to mount an immediate or a delayed-type immune response against human antigens. This durable state of unresponsiveness was evaluated by a complement-mediated cytotoxicity assay, with a mixed lymphocyte culture method and confirmed by the abrogation of the humoral (antibody response to human erythrocytes) and of the cell-mediated (popliteal lymph node test) immune responses in vivo. Our findings demonstrate the capacity of human plasma-derived transferrins to induce a state of durable unresponsiveness (xenogeneic tolerance?) in mice when administered with human antigens in the course of regeneration of stem cells in the bone marrow and lymphatic organs.
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10
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van Pelt J, Bakker JA, Velmans MH, Spaapen LJ. Carbohydrate-deficient transferrin values in neonatal and umbilical cord blood. J Inherit Metab Dis 1996; 19:253-6. [PMID: 8739979 DOI: 10.1007/bf01799443] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- J van Pelt
- Department of Clinical Chemistry, st Maartens Gasthuis, Venlo, The Netherlands
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11
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de Smit MH, Hoefkens P, de Jong G, van Duin J, van Knippenberg PH, van Eijk HG. Optimized bacterial production of nonglycosylated human transferrin and its half-molecules. Int J Biochem Cell Biol 1995; 27:839-50. [PMID: 7584619 DOI: 10.1016/1357-2725(95)00040-v] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Transferrin is a glycoprotein functioning in iron transport in higher eukaryotes, and consists of two highly homologous domains. To study the function of the glycan residues attached exclusively to the C-terminal domain, we have constructed a plasmid allowing production of nonglycosylated human transferrin in Escherichia coli. By molecular biological and genetic techniques, production was stepped up to 60 mg/l. Similar plasmids were constructed for production of the two half-transferrins. The recombinant proteins accumulate in inclusion-body-like aggregates, where they appear to bind iron without causing bacteriostasis. Proteins active in iron binding have been purified from these inclusion bodies.
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Affiliation(s)
- M H de Smit
- Leiden Institute of Chemistry, Department of Biochemistry, Gorlaeus Laboratories, Leiden University, The Netherlands
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12
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Kilár F, Hjertén S. Unfolding of human serum transferrin in urea studied by high-performance capillary electrophoresis. J Chromatogr A 1993; 638:269-76. [PMID: 8331139 DOI: 10.1016/0021-9673(93)83438-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
High-performance capillary electrophoresis (HPCE) was used to monitor the progress of the unfolding of human serum transferrin in urea. Denaturation curves of the transferrin forms were constructed plotting the migration times corrected for the viscosity vs. the concentration of urea in the buffer. The practical advantage of capillary zone electrophoresis is the short analysis time, 5-15 min, as compared with slab-gel experiments, which require overnight runs for similar purposes. The resolution increased with the urea concentration, and hence high concentrations are beneficial for quantitative and qualitative analysis of mixtures of transferrin forms. Unfolding intermediates of the isoforms, which interconvert to the unfolded state slowly compared with the time scale of the electrophoretic separation, and also the completely unfolded isoforms were resolved and detected simultaneously when iron-free transferrin was subjected to denaturation by urea at concentrations between 3 and 6 M. However, no unfolding intermediates were observed with transferrin isoforms containing two iron atoms (i.e. diferric transferrin molecules), which accordingly are strongly resistant to urea denaturation. The unfolding of the transferrin isoforms depends on the iron content of the complexes, but not the carbohydrate content. HPCE in the presence of urea in this mode has the potential to become an analytical tool for diagnosis of diseases in which the transferrin patterns change.
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Affiliation(s)
- F Kilár
- Institute of Biochemistry, Uppsala University, Sweden
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13
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de Jong G, van Noort WL, Feelders RA, de Jeu-Jaspars CM, van Eijk HG. Adaptation of transferrin protein and glycan synthesis. Clin Chim Acta 1992; 212:27-45. [PMID: 1486679 DOI: 10.1016/0009-8981(92)90135-d] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We report the patterns of variability in transferrin structure in pregnancy, iron deficiency anemia, women using oral contraceptives, nonanaemic rheumatoid arthritis, iron deficient rheumatoid arthritis and anemia of the chronic diseases. Changes in microheterogeneity were assessed by crossed immuno isoelectric focusing of serum transferrin. Intra-individual variation in the control group was minimal. Equally, inter-individual variation in controls and groups with established stable disease was very limited. In pregnancy an increase in transferrin concentration was accompanied by redirection of glycan synthesis to the highly sialylated and highly branched glycans, an effect also shown in women using oral contraceptives. Iron deficiency anemia was accompanied by increased protein core synthesis without the large shifts in the microheterogeneity pattern as seen in pregnancy at similar transferrin concentration. In contrast to this, rheumatoid arthritis was accompanied by decreased protein synthesis while the microheterogeneity pattern shifted significantly towards the highly branched glycans. Interpreted in the respective pathophysiological contexts results show that: (1) N-linked glycosylation of transferrin is a strictly controlled process, both in the physiological states and in disease. (2) Microheterogeneity is determined independently from transferrin protein synthetic rate. (3) Provisionally observed changes in the glycosylation can modulate the biological activity of the glycoprotein and as a result redirect internal iron fluxes. This proposition can be applied to altered iron metabolism in both pregnancy, oral contraceptives and rheumatoid arthritis. Changes are not operative in iron deficiency because qualitatively iron metabolism is not altered in this state.
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Affiliation(s)
- G de Jong
- Department of Chemical Pathology, Erasmus University, Rotterdam, The Netherlands
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14
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Feelders RA, Vreugdenhil G, de Jong G, Swaak AJ, van Eijk HG. Transferrin microheterogeneity in rheumatoid arthritis. Relation with disease activity and anemia of chronic disease. Rheumatol Int 1992; 12:195-9. [PMID: 1290022 DOI: 10.1007/bf00302152] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We studied the relation between disease activity in rheumatoid arthritis (RA) and the microheterogeneity of transferrin. Using crossed immuno isoelectric focusing, transferrin microheterogeneity patterns were analyzed in sera of healthy individuals, nonanemic RA patients, iron deficient RA patients and RA patients with the anemia of chronic disease (ACD). In all RA groups a significant shift in the microheterogeneity pattern was observed, reflecting increased synthesis of transferrins with highly branched glycan chains. Increased disease activity correlated with both the induction of ACD and the change in transferrin glycosylation, which was, therefore, most pronounced in ACD. Generally, an increased synthesis of glycoproteins is accompanied by alterations in their glycosylation pattern. Since transferrin is a negative acute phase protein, our results indicated that changes in synthetic rates and changes in glycosylation induced in the acute phase response are regulated independently.
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Affiliation(s)
- R A Feelders
- Department of Chemical Pathology, Erasmus University, Rotterdam, The Netherlands
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15
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van Dijk JP, van Noort WL, Kroos MJ, Starreveld JS, van Eijk HG. Isotransferrins and pregnancy: a study in the guinea pig. Clin Chim Acta 1991; 203:1-16. [PMID: 1769115 DOI: 10.1016/0009-8981(91)90151-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
During pregnancy the serum isotransferrin pattern changes towards transferrins with more complex carbohydrate chains. The main pregnancy-related isotransferrin (TfFast) and the most common isotransferrin in the non-pregnant guinea pig (TfSlow) were isolated and characterized. TfSlow had one biantennary- and TfFast one triantennary glycan chain. Is there a functional explanation for this pregnancy-related shift towards more complex glycan chain structure? We studied this question in the context of maternal and fetal erythropoiesis. In vitro incubations of maternal bone marrow cells (MBMC) and fetal erythroid liver cells (FELC) with doubly labelled TfSlow and TfFast revealed only slight differences in affinities for the transferrin receptor. Ka(TfSlow) = 0.17 mumol/l; Ka(TfFast) = 0.15 mumol/l. MBMC and FELC had equal Vmax values both for TfSlow and TfFast. Vmax = 100 Fe atoms/transferrin receptor.hour. Irrespective the cell population TfSlow and TfFast showed equal rates for endo- and exocytosis. kendo. = 0.3750 min-1, kexo. = 0.1450 min-1. It is concluded that the described shift in isotransferrin pattern is not functionally related to maternal or fetal erythropoiesis.
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Affiliation(s)
- J P van Dijk
- Erasmus University Rotterdam, Department of Chemical Pathology, The Netherlands
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16
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Affiliation(s)
- K Thorstensen
- Department of Clinical Chemistry, University Hospital, Trondheim, Norway
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17
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Abstract
The chemistry and molecular biology of transferrin is discussed. The discussion covers the genetic control of transferrin synthesis, its intracellular synthesis, intra- and extracellular transport, and its interaction with transferrin receptors. The role of transferrin in iron metabolism is evaluated, both with regard to iron uptake by transferrin as to iron uptake from transferrin by different cells. The knowledge on the biochemical mechanisms involved in iron uptake is presented, with special reference to the triple role of the acidification of endocytotic vesicles. Apart from its traditional role in iron metabolism, transferrin acts as a growth factor. A distinction of two groups of growth-stimulating properties of transferrin has been made. As an early effect, membranous and intracellular changes are initiated, possibly based on electrochemical effects on the cell. The late effects seem to relate to its role in iron transport. Interestingly, the early growth stimulating effects can be segregated from the former function of transferrin and strictly speaking neither depend on iron nor on the transferrin molecule itself. Also the trophic effect of transferrin on several cell types has been described. Hypotheses concerning the biochemical basis of this effect are presented and within this context a new hypothesis on the differential occupation of iron binding sites of serum transferrin is forwarded. Examples of the applicability of present understanding of the biology of transferrin in clinical settings are presented.
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Affiliation(s)
- G de Jong
- Department of Chemical Pathology, Erasmus University Rotterdam, The Netherlands
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18
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Abstract
Over the last 10 years there has been steady progress in our understanding of the structure of the iron-binding proteins transferrin and ferritin, and the transferrin receptor. In the last few years there have been very rapid developments in understanding of the genetics of these proteins and the regulation of synthesis. This review includes a description of gene localization and structure, the regulation of protein synthesis and the structure of proteins of the transferrin family, the transferrin receptor and the iron storage protein ferritin.
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Affiliation(s)
- M Worwood
- Department of Haematology, University of Wales College of Medicine, Heath Park, Cardiff, UK
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