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  • 1.
    Karlsson, Isabella
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ndreu, Lorena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Quaranta, Alessandro
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Thorsén, Gunnar
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Glycosylation patterns of selected proteins in individual serum and cerebrospinal fluid samples2017In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 145, p. 431-439Article in journal (Refereed)
    Abstract [en]

    A method we previously developed has been applied to the determination of the glycosylation pattern of specific proteins in biological samples. Six proteins (alpha-1-anthrypsin, transferrin, haptoglobin, Cl inhibitor, alpha-1 acid glycoprotein, and immunoglobulin G) were studied in serum samples from five individuals and cerebrospinal fluid (CSF) samples from three individuals, to investigate the expected normal distribution of glycosylation patterns and to assess whether this methodology can be used to discriminate between samples from different individuals. For serum samples, the differences were shown to be small, while much larger differences were found for the CSF samples, with a greater number of glycoforms present. This can be linked to the occurrence of differential glycosylation in proteins expressed in the brain compared with proteins expressed elsewhere in the body. The developed method could distinguish differences in the glycosylation pattern of specific proteins in the individual samples, which was not reflected in the glycan content of total CSF. This is the first time that the glycoforms of several of these proteins have been investigated in CSF.

  • 2.
    Karlsson, Isabella
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Samuelsson, Kristin
    Ponting, David J.
    Törnqvist, Margareta
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Nilsson, Ulrika
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Peptide Reactivity of Isothiocyanates - Implications for Skin Allergy2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 21203Article in journal (Refereed)
    Abstract [en]

    Skin allergy is a chronic condition that affects about 20% of the population of the western world. This disease is caused by small reactive compounds, haptens, able to penetrate into the epidermis and modify endogenous proteins, thereby triggering an immunogenic reaction. Phenyl isothiocyanate (PITC) and ethyl isothiocyanate (EITC) have been suggested to be responsible for allergic skin reactions to chloroprene rubber, the main constituent of wetsuits, orthopedic braces, and many types of sports gear. In the present work we have studied the reactivity of the isothiocyanates PITC, EITC, and tetramethylrhodamine-6-isothiocyanate (6-TRITC) toward peptides under aqueous conditions at physiological pH to gain information about the types of immunogenic complexes these compounds may form in the skin. We found that all three compounds reacted quickly with cysteine moieties. For PITC and 6-TRITC the cysteine adducts decomposed over time, while stable adducts with lysine were formed. These experimental findings were verified by DFT calculations. Our results may suggest that the latter are responsible for allergic reactions to isothiocyanates. The initial adduct formation with cysteine residues may still be of great importance as it prevents hydrolysis and facilitates the transport of isothiocyanates into epidermis where they can form stable immunogenic complexes with lysine-containing proteins.

  • 3.
    Karlsson, Isabella
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Samuelsson, Kristin
    Simonsson, Carl
    Stenfeldt, Anna-Lena
    Nilsson, Ulrika
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Jonsson, Charlotte
    Karlberg, Ann-Therese
    The Fate of a Hapten - From the Skin to Modification of Macrophage Migration Inhibitory Factor (MIF) in Lymph Nodes2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 2895Article in journal (Refereed)
    Abstract [en]

    Skin (contact) allergy, the most prevalent form of immunotoxicity in humans, is caused by low molecular weight chemicals (haptens) that penetrate stratum corneum and modify endogenous proteins. The fate of haptens after cutaneous absorption, especially what protein(s) they react with, is largely unknown. In this study the fluorescent hapten tetramethylrhodamine isothiocyanate (TRITC) was used to identify hapten-protein conjugates in the local lymph nodes after topical application, as they play a key role in activation of the adaptive immune system. TRITC interacted with dendritic cells but also with T and B cells in the lymph nodes as shown by flow cytometry. Identification of the most abundant TRITC-modified protein in lymph nodes by tandem mass spectrometry revealed TRITC-modification of the N-terminal proline of macrophage migration inhibitory factor (MIF) - an evolutionary well-conserved protein involved in cell-mediated immunity and inflammation. This is the first time a hapten-modified protein has been identified in lymph nodes after topical administration of the hapten. Most haptens are electrophiles and can therefore modify the N-terminal proline of MIF, which has an unusually reactive amino group under physiological conditions; thus, modification of MIF by haptens may have an immunomodulating role in contact allergy as well as in other immunotoxicity reactions.

  • 4.
    Quaranta, Alessandro
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Karlsson, Isabella
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ndreu, Lorena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Marini, Federico
    Ingelsson, Martin
    Thorsén, Gunnar
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Glycosylation profiling of selected proteins in cerebrospinal fluid from Alzheimer's disease and healthy subjects2019In: Analytical Methods, ISSN 1759-9660, E-ISSN 1759-9679, Vol. 11, no 26, p. 3331-3340Article in journal (Refereed)
    Abstract [en]

    Alteration of glycosylation has been observed in several diseases, such as cancer and neurodegenerative disorders. The study of changes in glycosylation could lead to a better understanding of mechanisms underlying these diseases and to the identification of new biomarkers. In this work the N-linked glycosylation of five target proteins in cerebrospinal fluid (CSF) from Alzheimer's disease (AD) patients and healthy controls have been analyzed for the first time. The investigated proteins, transferrin (TFN), alpha-1-antitrypsin (AAT), C1-inhibitor, immunoglobulin G (IgG), and alpha-1-acid glycoprotein (AGP), were selected based on the availability of VHH antibody fragments and their potential involvement in neurodegenerative and inflammation diseases. AD patients showed alterations in the glycosylation of low abundance proteins, such as C1-inhibitor and alpha-1-acid glycoprotein. These alterations would not have been detected if the glycosylation profile of the total CSF had been analyzed, due to the masking effect of the dominant profiles of high abundance glycoproteins, such as IgG. Information obtained from single proteins was not sufficient to correctly classify the two sample groups; however, by using an advanced multivariate technique a total non-error rate of 72 +/- 3% was obtained. In fact, the corresponding model was able to correctly classify 71 +/- 4% of the healthy subjects and 74 +/- 7% of the AD patients. Even if the results were not conclusive for AD, this approach could be extremely useful for diseases in which glycosylation changes are reported to be more extensive, such as several types of cancer and autoimmune diseases.

  • 5.
    Quaranta, Alessandro
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Spasova, Maya
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Passarini, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Karlsson, Isabella
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ndreu, Lorena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Thorsén, Gunnar
    Ilag, Leopold
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    N-glycosylation profiling of selected intact proteins by high-resolution mass spectrometry (MS) and glycan analysis using ion mobility-MS/MSManuscript (preprint) (Other academic)
    Abstract [en]

    Glycosylation influences structure and functionality of glycoproteins, and is regulated by genetic and environmental factors. Types and abundances of glycans on glycoproteins can vary due to diseases like cancer, inflammation, autoimmune and neurodegenerative disorders. Due to the crucial role of glycans in modulating protein function, glycosylation analysis is of prime importance in glycoprotein biopharmaceuticals quality control. We present a method for identification and quantification of glycoforms directly on intact proteins after immunoaffinity purification from biological fluids. The method was validated and applied to serum transferrin and to the biopharmaceutical trastuzumab. The accuracy ranged from 2.1 to 7.9%, and intra- and inter-day precision were 3.1 and 8.2%. Sensitivity and linearity were suitable for serum analysis and LOQs were calculated to be 3.1 (transferrin) and 4.4 (trastuzumab) µg/mL. Application to transferrin from five healthy serum samples yielded concentrations in agreement with blood reference levels (1.95-3.11 mg/mL). The structures of the identified glycans were assigned by ion mobility spectrometry coupled to tandem mass spectrometry. No chromatographic separation was required, and sample preparation was performed in a semi-automatic way, reducing the analysis time to 1-3 minutes. Hence, this method could be suitable for clinical laboratories and for quality control on large batches of biopharmaceuticals.

  • 6.
    Sroka-Bartnicka, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Karlsson, Isabella
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ndreu, Lorena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Quaranta, Alessandro
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Pijnappel, Matthijs
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Thorsén, Gunnar
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Particle-based N-linked glycan analysis of selected proteins from biological samples using nonglycosylated binders2017In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 132, p. 125-132Article in journal (Refereed)
    Abstract [en]

    Glycosylation is one of the most common and important post-translational modifications, influencing both the chemical and the biological properties of proteins. Studying the glycosylation of the entire protein population of a sample can be challenging because variations in the concentrations of certain proteins can enhance or obscure changes in glycosylation. Furthermore, alterations in the glycosylation pattern of individual proteins, exhibiting larger variability in disease states, have been suggested as biomarkers for different types of cancer, as well as inflammatory and neurodegenerative diseases. In this paper, we present a rapid and efficient method for glycosylation analysis of individual proteins focusing on changes in the degree of fucosylation or other alterations to the core structure of the glycans, such as the presence of bisecting N-acetylglucosamines and a modified degree of branching. Streptavidin-coated magnetic beads are used in combination with genetically engineered immunoaffinity binders, called VHH antibody fragments. A major advantage of the VHHs is that they are nonglycosylated; thus, enzymatic release of glycans from the targeted protein can be performed directly on the beads. After deglycosylation, the glycans are analyzed by MALDI-TOF-MS. The developed method was evaluated concerning its specificity, and thereafter implemented for studying the glycosylation pattern of two different proteins, alpha-1-antitrypsin and transferrin, in human serum and cerebrospinal fluid. To our knowledge, this is the first example of a protein array-type experiment that employs bead-based immunoaffinity purification in combination with mass spectrometry analysis for fast and efficient glycan analysis of individual proteins in biological fluid.

1 - 6 of 6
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