Raman spectroscopy can recognize the KMT2A rearrangement as a distinct subtype of leukemia.

Acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) are the two most common hematologic malignancies, challenging to treat and associated with high recurrence and mortality rates. This work aims to identify specific Raman biomarkers of ALL cells with the KMT2A gene rearrangement (KMT2A-r), representing a highly aggressive subtype of childhood leukemia with a poor prognosis. The proposed approach combines the sensitivity and specificity of Raman spectroscopy with machine learning and allows us to distinguish not only myelo- and lymphoblasts but also discriminate B-cell precursor (BCP) ALL with KMT2A-r from other blasts of BCP-ALL. We have found that KMT2A-r ALL cells fixed with 0.5% glutaraldehyde exhibit a unique spectroscopic profile that enables us to identify this subtype from other leukemias and normal cells. Therefore, a rapid and label-free method was developed to identify ALL blasts with KMT2A-r based on the ratio of the two Raman bands assigned to phenylalanine - 1040 and 1008 cm-1. This is the first time that a particular group of leukemic cells has been identified in a label-free way. The identified biomarker can be used as a screening method in diagnostic laboratories or non-reference medical centers.

Raman classification of selected subtypes of acute lymphoblastic leukemia (ALL).

B-cell precursor acute lymphoblastic leukemia (BCP-ALL) with chromosome translocations like KMT2A gene rearrangement (KMT2A-r) and BCR-ABL1 fusion gene have been recognized as crucial drivers in both BCP-ALL leukemogenesis and treatment management. Standard diagnostic protocols for proliferative diseases of the hematopoietic system, like KMT2A-r-ALL, are genetically based and strongly molecularly oriented. Therefore, an efficient diagnostic procedure requires not only experienced and multidisciplinary laboratory staff but also considerable instrumentation and material costs. In recent years, a Raman spectroscopy method has been increasingly used to detect subtle chemical changes in individual cells resulting from stress or disease. Therefore, the objective of this study was to identify Raman signatures for the molecular subtypes and to develop a classification method based on the unique spectroscopic profile of in vitro models that represent specific aberrations aimed at KMT2A-r (RS4;11, and SEM) and the BCR-ABL1 fusion gene (SUP-B15, BV-173, and SD-1). Data analysis was based on chemometric methods, i.e. principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and support vector machine (SVM). The PCA-based multivariate model was used for pattern recognition of each investigated group of cells while PLS-DA and SVM were used to build models for the discrimination of spectra from the studied BCP-ALL molecular subtypes. The results showed that the studied molecular subtypes of ALL have characteristic spectroscopic profiles reflecting their peculiar biochemical state. The content of lipids (1600 cm-1), nucleic acids (789 cm-1), and haemoproteins (754, 1130, and 1315 cm-1), which are crucial in cell metabolism, was indicated as the main source of differentiation between subtypes. Identification of spectroscopic markers of cells with BCR-ABL1 or KMT2A-r may be useful in pharmacological studies to monitor the effectiveness of chemotherapy and further to understand differences in molecular responses between leukemia primary cells and cell lines.

Raman-based spectrophenotyping of the most important cells of the immune system.

INTRODUCTION: Human peripheral blood mononuclear cells (PBMCs) are a heterogeneous population of cells that includes T and B lymphocytes. The total number of lymphocytes and their percentage in the blood can be a marker for the diagnosis of several human diseases. Currently, cytometric methods are widely used to distinguish subtypes of leukocytes and quantify their number. These techniques use cell immunophenotyping, which is limited by the number of fluorochrome-labeled antibodies that can be applied simultaneously. OBJECTIVE: B and T lymphocytes were isolated from peripheral blood obtained from healthy human donors. METHODS: The immunomagnetic negative selection was used for the enrichment of B and T cells fractions, and their purity was assessed by flow cytometry. Isolated cells were fixed with 0.5% glutaraldehyde and measured using confocal Raman imaging. K-means cluster analysis, principal component analysis and partial least squares discriminant methods were applied for the identification of spectroscopic markers to distinguish B and T cells. HPLC was the reference method for identifying carotene in T cells. RESULTS: Reliable discrimination between T and B lymphocytes based on their spectral profile has been demonstrated using label-free Raman imaging and chemometric analysis. The presence of carotene in T lymphocytes (in addition to the previously reported in plasma) was confirmed and for the first time unequivocally identified as ß-carotene. In addition, the molecular features of the lymphocytes nuclei were found to support the discriminant analysis. It has been shown that although the presence of carotenoids in T cells depends on individual donor variability, the reliable differentiation between lymphocytes is possible based on Raman spectra collected from individual cells. CONCLUSIONS: This proves the potential of Raman spectroscopy in clinical diagnostics to automatically differentiate between cells that are an important component of our immune system.

Towards Raman-Based Screening of Acute Lymphoblastic Leukemia-Type B (B-ALL) Subtypes.

Acute lymphoblastic leukemia (ALL) is the most common type of malignant neoplasms in the pediatric population. B-cell precursor ALLs (BCP-ALLs) are derived from the progenitors of B lymphocytes. Traditionally, risk factors stratifying therapy in ALL patients included age at diagnosis, initial leukocytosis, and the response to chemotherapy. Currently, treatment intensity is modified according to the presence of specific gene alterations in the leukemic genome. Raman imaging is a promising diagnostic tool, which enables the molecular characterization of cells and differentiation of subtypes of leukemia in clinical samples. This study aimed to characterize and distinguish cells isolated from the bone marrow of patients suffering from three subtypes of BCP-ALL, defined by gene rearrangements, i.e., BCR-ABL1 (Philadelphia-positive, t(9;22)), TEL-AML1 (t(12;21)) and TCF3-PBX1 (t(1;19)), using single-cell Raman imaging combined with multivariate statistical analysis. Spectra collected from clinical samples were compared with single-cell spectra of B-cells collected from healthy donors, constituting the control group. We demonstrated that Raman spectra of normal B cells strongly differ from spectra of their malignant counterparts, especially in the intensity of bands, which can be assigned to nucleic acids. We also showed that the identification of leukemia subtypes could be automated with the use of chemometric methods. Results prove the clinical suitability of Raman imaging for the identification of spectroscopic markers characterizing leukemia cells.

Glycosylation in Autoimmune Diseases.

Autoimmune diseases are accompanied by changes in protein glycosylation, in both the immune system and target tissues. The best-studied alteration in autoimmunity is agalactosylation of immunoglobulin G (IgG), characterized primarily in rheumatoid arthritis (RA), and then detected also in systemic lupus erythematosus (SLE), inflammatory bowel disease (IBD), and multiple sclerosis (MS). The rebuilding of IgG N-glycans in RA correlates with the relapses and remissions of the disease, is associated with physiological states such as pregnancy but also depends on applied anti-inflammatory therapy. In turn, a decreased core fucosylation of the whole pool of IgG N-glycans is a serum glycomarker in autoimmune thyroid diseases (AITD) encompassing Hashimoto's thyroiditis (HT) and Grave's disease (GD). However, fucosylation of anti-thyroglobulin IgG (an immunological marker of HT) was elevated in HT serum. Core fucosylation of IgG oligosaccharides was also lowered in MS and SLE. In AITD and IBD, chronic inflammation T lymphocytes showed the reduced expression of MGAT5 gene encoding ß1,6-N-acetylglucosaminyltransferase V (GnT-V) responsible for ß1,6-branching of N-glycans, which is important for T cell receptor activation. Structural changes of glycans have a profound effect on the pro-inflammatory activity of immune cells and serum immune proteins, including IgG in autoimmunity.

Decreased Immunoglobulin G Core Fucosylation, A Player in Antibody-dependent Cell-mediated Cytotoxicity, is Associated with Autoimmune Thyroid Diseases.

Autoimmune thyroid diseases (AITD) are the most common group of autoimmune diseases, associated with lymphocyte infiltration and the production of thyroid autoantibodies, like thyroid peroxidase antibodies (TPOAb), in the thyroid gland. Immunoglobulins and cell-surface receptors are glycoproteins with distinctive glycosylation patterns that play a structural role in maintaining and modulating their functions. We investigated associations of total circulating IgG and peripheral blood mononuclear cells glycosylation with AITD and the influence of genetic background in a case-control study with several independent cohorts and over 3,000 individuals in total. The study revealed an inverse association of IgG core fucosylation with TPOAb and AITD, as well as decreased peripheral blood mononuclear cells antennary α1,2 fucosylation in AITD, but no shared genetic variance between AITD and glycosylation. These data suggest that the decreased level of IgG core fucosylation is a risk factor for AITD that promotes antibody-dependent cell-mediated cytotoxicity previously associated with TPOAb levels.

The Contribution of IgG Glycosylation to Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC) and Complement-Dependent Cytotoxicity (CDC) in Hashimoto's Thyroiditis: An in Vitro Model of Thyroid Autoimmunity.

Antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) are involved in destruction of thyroid tissue in Hashimoto's thyroiditis (HT). N-glycosylation of the Fc fragment affects the effector functions of IgG by enhancing or suppressing the cytotoxicity effect. The aim of the present study was to assess the impact of HT-specific IgG glycosylation in ADCC and CDC, using in vitro models. The normal thyroid Nthy-ori 3-1 cell line and thyroid carcinoma FTC-133 cells were used as the target cells. Peripheral blood mononuclear cells (PBMCs) from healthy donors and the HL-60 human promyelotic leukemia cell line served as the effector cells. IgG was isolated from sera of HT and healthy donors and then treated with α2-3,6,8-neuraminidase to cut off sialic acids (SA) from N-glycans. We observed more intensive cytotoxicity in the presence of IgG from HT patients than in the presence of IgG from healthy donors. Removal of SA from IgG N-glycans increased ADCC intensity and reduced CDC. We conclude that the enhanced thyrocyte lysis resulted from the higher anti-TPO content in the whole IgG pool of HT donors and from altered IgG glycosylation in HT autoimmunity.

Altered N-glycan profile of IgG-depleted serum proteins in Hashimoto's thyroiditis.

BACKGROUND: Hashimoto's thyroiditis (HT) is an autoimmune disease characterized by chronic inflammation of thyroid gland. Although HT is the most common cause of hypothyroidism, the pathogenesis of this disease is not fully understood. Glycosylation of serum proteins was examined in HT only to a limited extent. The study was designed to determine the glycosylation pattern of IgG-depleted sera from HT patients. METHODS: Serum N-glycans released by N-glycosidase F (PNGase F) digestion were analyzed by normal-phase high-performance liquid chromatography (NP-HPLC). N-glycan structures in each collected HPLC fraction were determined by liquid chromatography-mass spectrometry (LC-MS) and exoglycosidase digestion. Fucosylation and sialylation was also analyzed by lectin blotting. RESULTS: The results showed an increase of monosialylated tri-antennary structure (A3G3S1) and disialylated diantennary N-glycan with antennary fucose (FA2G2S2). Subsequently, we analyzed the serum N-glycan profile by lectin blotting using lectins specific for fucose and sialic acid. We found a significant decrease of Lens culinaris agglutinin (LCA) staining in HT samples, which resulted from the reduction of α1,6-linked core fucose in HT serum. We also observed an increase of Maackia amurensis II lectin (MAL-II) reaction in HT due to the elevated level of α2,3-sialylation in HT sera. CONCLUSIONS: The detected alterations of serum protein sialylation might be caused by chronic inflammation in HT. The obtained results complete our previous IgG N-glycosylation analysis in autoimmune thyroid patients and show that the altered N-glycosylation of serum proteins is characteristic for autoimmunity process in HT. General Significance Thyroid autoimmunity is accompanied by changes of serum protein sialylation.

Glycosylation in the Thyroid Gland: Vital Aspects of Glycoprotein Function in Thyrocyte Physiology and Thyroid Disorders.

The key proteins responsible for hormone synthesis in the thyroid are glycosylated. Oligosaccharides strongly affect the function of glycosylated proteins. Both thyroid-stimulating hormone (TSH) secreted by the pituitary gland and TSH receptors on the surface of thyrocytes contain N-glycans, which are crucial to their proper activity. Thyroglobulin (Tg), the protein backbone for synthesis of thyroid hormones, is a heavily N-glycosylated protein, containing 20 putative N-glycosylated sites. N-oligosaccharides play a role in Tg transport into the follicular lumen, where thyroid hormones are produced, and into thyrocytes, where hyposialylated Tg is degraded. N-glycans of the cell membrane transporters sodium/iodide symporter and pendrin are necessary for iodide transport. Some changes in glycosylation result in abnormal activity of the thyroid and alteration of the metabolic clearance rate of hormones. Alteration of glycan structures is a pathological process related to the progression of chronic diseases such as thyroid cancers and autoimmunity. Thyroid carcinogenesis is accompanied by changes in sialylation and fucosylation, ß1,6-branching of glycans, the content and structure of poly-LacNAc chains, as well as O-GlcNAcylation, while in thyroid autoimmunity the main processes affected are sialylation and fucosylation. The glycobiology of the thyroid gland is an intensively studied field of research, providing new data helpful in understanding the role of the sugar component in thyroid protein biology and disorders.

ß1,6-branched complex-type N-glycans affect FAK signaling in metastatic melanoma cells.

Integrin-dependent binding of the cell to extracellular matrix (ECM) is a key activator of the focal adhesion kinase (FAK) signaling pathway. N-glycosylation of integrins affects their interactions with ECM proteins. Using WM266-4 cells with overexpression of ß1,6-acetylglucosaminyltransferase V, we showed that ß1,6-branched N-glycans increased tyrosine phosphorylation of FAK in metastatic melanoma cells, resulting in enhanced migration on vitronectin (VN). The co-localization of αvß3 integrin and FAK in focal adhesions of melanoma cells growing on VN indicates their interaction in signal transduction. Melanoma cell migration on VN was mediated by αvß3 caring overexpressed ß1,6-branched structures, important for FAK upregulation.

[The role of protein glycosylation in immune system]. / Rola glikozylacji bialek ukladu odpornosciowego.

Glycosylation is one of the most frequent post-translational modifications of proteins. The majority of cell surface and secreted proteins involved in immune response is glycosylated. The structural diversity of glycans depends on monosaccharide composition, type of glycosidic linkage and branching. These structural modifications determine a great variability of glycoproteins. The oligosaccharide components of proteins are regulated mostly by expression of glycosyltransferases and glycosidases and many environmental factors. Glycosylation influences the function of all immune cells. Glycans play a crucial role in intercellular contacts and leukocytes migration. These interactions are important in activation and proliferation of leukocytes and during immune response. The key immune proteins, such as TCR, MHC, TLR and antibodies are glycosylated. Sugars on the surface of pathogens and self-surface glycoproteins are recognized by special carbohydrate binding proteins called lectins. Changes of glycan structure are common in many pathological processes occurring in immune system, therefore they are used as molecular markers of different diseases.

Immunosuppressive drugs affect high-mannose/hybrid N-glycans on human allostimulated leukocytes.

N-glycosylation plays an important role in the majority of physiological and pathological processes occurring in the immune system. Alteration of the type and abundance of glycans is an element of lymphocyte differentiation; it is also common in the development of immune-mediated inflammatory diseases. The N-glycosylation process is very sensitive to different environmental agents, among them the pharmacological environment of immunosuppressive drugs. Some results show that high-mannose oligosaccharides have the ability to suppress different stages of the immune response. We evaluated the effects of cyclosporin A (CsA) and rapamycin (Rapa) on high-mannose/hybrid-type glycosylation in human leukocytes activated in a two-way mixed leukocyte reaction (MLR). CsA significantly reduced the number of leukocytes covered by high-mannose/hybrid N-glycans, and the synergistic action of CsA and Rapa led to an increase of these structures on the remaining leukocytes. This is the first study indicating that ß1 and ß3 integrins bearing high-mannose/hybrid structures are affected by Rapa and CsA. Rapa taken separately and together with CsA changed the expression of ß1 and ß3 integrins and, by regulating the protein amount, increased the oligomannose/hybrid-type N-glycosylation on the leukocyte surface. We suggest that the changes in the glycosylation profile of leukocytes may promote the development of tolerance in transplantation.