Quantitative determination of the glycosaminoglycan Delta-disaccharide composition of serum, platelets and granulocytes by reversed-phase high-performance liquid chromatography

Separation and purification of bovine nasal cartilage-derived chondroitin sulfate and evaluation of its binding to bovine serum albumin

This study employs an optimized and environmentally friendly method to extract and purify chondroitin sulfate (CS) from bovine nasal cartilage using enzymatic hydrolysis, ethanol precipitation, and DEAE Sepharose Fast Flow column chromatography. The extracted CS, representing 44.67 % ± 0.0016 of the cartilage, has a molecular weight of 7.62 kDa. Characterization through UV, FT-IR, NMR spectroscopy, and 2-aminoacridone derivatization HPLC revealed a high content of sulfated disaccharides, particularly ΔDi4S (73.59 %) and ΔDi6S (20.61 %). Interaction studies with bovine serum albumin (BSA) using fluorescence spectroscopy and molecular docking confirmed a high-affinity, static quenching interaction with a single binding site, primarily mediated by van der Waals forces and hydrogen bonding. The interaction did not significantly alter the polarity or hydrophobicity of BSA aromatic amino acids. These findings provide a strong foundation for exploring the application of CS in tissue engineering and drug delivery systems, leveraging its unique interaction with BSA for targeted delivery and enhanced efficacy.

Glycosaminoglycans: Participants in Microvascular Coagulation of Sepsis

Sepsis represents a syndromic response to infection and frequently acts as a common pathway leading to fatality in the context of various infectious diseases globally. The pathology of severe sepsis is marked by an excess of inflammation and activated coagulation. A substantial contributor to mortality in sepsis patients is widespread microvascular thrombosis-induced organ dysfunction. Multiple lines of evidence support the notion that sepsis induces endothelial damage, leading to the release of glycosaminoglycans, potentially causing microvascular dysfunction. This review aims to initially elucidate the relationship among endothelial damage, excessive inflammation, and thrombosis in sepsis. Following this, we present a summary of the involvement of glycosaminoglycans in coagulation, elucidating interactions among glycosaminoglycans, platelets, and inflammatory cells. In this section, we also introduce a reasoned generalization of potential signal pathways wherein glycosaminoglycans play a role in clotting. Finally, we discuss current methods for detecting microvascular conditions in sepsis patients from the perspective of glycosaminoglycans. In conclusion, it is imperative to pay closer attention to the role of glycosaminoglycans in the mechanism of microvascular thrombosis in sepsis. Dynamically assessing glycosaminoglycan levels in patients may aid in predicting microvascular conditions, enabling the monitoring of disease progression, adjustment of clinical treatment schemes, and mitigation of both acute and long-term adverse outcomes associated with sepsis.

A chondroitin sulfate purified from shark cartilage and bovine serum albumin interaction activity

Chondroitin sulfate (CS) was extracted and purified from shark cartilage, and its interaction with bovine serum albumin (BSA) were studied. The content of chondroitin sulfate in shark cartilage was 29.97 % using the 1,9-dimethyl-methylene blue method. The molecular weight of CS was determined to be 62.464 kDa by high-performance gel permeation chromatography. UV and FT-IR spectroscopy identified the characteristics of CS and its functional group information. NMR spectroscopy and disaccharide derivatization revealed that CS was predominantly composed of disulfated disaccharides, specifically ΔDi4,6S. Fluorescence quenching experiments indicated that the interaction between CS and BSA exhibited static quenching, with a binding site number of 1. The binding process was primarily mediated by van der Waals forces and hydrogen bonds. Furthermore, synchronous and 3D fluorescence spectroscopy demonstrated that CS had minimal impact on the polarity and hydrophobicity of the microenvironment surrounding Tyr and Trp residues. UV-vis absorption and circular dichroism (CD) spectroscopy demonstrated the altered structure of BSA. The molecular docking analysis revealed that CS formed hydrogen bonds and salt bridges with BSA, predominantly binding to the IIA substructure domain of BSA. Investigating the interaction between CS and BSA holds the potential for enhancing its applications in drug delivery and tissue engineering endeavors.

Glycomics by ion mobility tandem mass spectrometry of chondroitin sulfate disaccharide domain in biglycan

Biglycan (BGN), a small leucine-rich repeat proteoglycan, is involved in a variety of pathological processes including malignant transformation, for which the upregulation of BGN was found related to cancer cell invasiveness. Because the functions of BGN are mediated by its chondroitin/dermatan sulfate (CS/DS) chains through the sulfates, the determination of CS/DS structure and sulfation pattern is of major importance. In this study, we have implemented an advanced glycomics method based on ion mobility separation (IMS) mass spectrometry (MS) and tandem MS (MS/MS) to characterize the CS disaccharide domains in BGN. The high separation efficiency and sensitivity of this technique allowed the discrimination of five distinct CS disaccharide motifs, of which four irregulated in their sulfation pattern. For the first time, trisulfated unsaturated and bisulfated saturated disaccharides were found in BGN, the latter species documenting the non-reducing end of the chains. The structural investigation by IMS MS/MS disclosed that in one or both of the CS/DS chains, the non-reducing end is 3-O-sulfated GlcA in a rather rare bisulfated motif having the structure 3-O-sulfated GlcA-4-O-sulfated GalNAc. Considering the role played by BGN in cancer cell spreading, the influence on this process of the newly identified sequences will be investigated in the future.

Simultaneous determination of heparan sulfate, chondroitin/dermatan sulfates, and hyaluronan glycosaminoglycan disaccharides by high-performance liquid chromatography using a reverse-phase column with adamantyl groups

Glycosaminoglycans (GAGs), which are one of the major components of proteoglycans, play a pivotal role in physiological processes such as signal transduction, cell adhesion, growth, and differentiation. Characterization of GAGs is challenging due to the tremendous structural diversity of heteropolysaccharides with numerous sulfate or carboxyl groups. In this present study, we examined the analysis of 2-aminobenzamide (2-AB) labeled GAG disaccharides by high-performance liquid chromatography (HPLC) using a reverse-phase (RP)-column with adamantyl groups. Under the analytical conditions, 17 types of 2-AB labeled GAG disaccharides derived from heparan sulfate, chondroitin/dermatan sulfates, and hyaluronan were sequentially separated in a single analysis. The analysis time was fast with high retention time reproducibility. Moreover, the RP-HPLC column with adamantyl groups allowed the quantification of GAGs in various biological samples, such as serum, cultured cells, and culture medium.

Production and HPLC-Based Disaccharide Analysis of Xyloside-Primed Glycosaminoglycans

Although glycosaminoglycans (GAGs) are known to be involved in a variety of physiological and pathological processes, knowledge about their expression by cells or tissues, the GAGome, is limited. Xylosides can be used to induce the formation of GAGs without the presence of a proteoglycan core protein. The administration of xylosides to living cells tends to result in a considerable amplification in GAG production, and the xylosides can, therefore, be used as analytical tools to study the GAG produced by a certain cell type. One of the most common ways to analyze the GAGs structurally is by disaccharide analysis, which involves depolymerization of the GAGs into disaccharides, fluorescent labeling of the disaccharides with 2-aminoacridone, and quantification using high-pressure liquid chromatography (HPLC). Here, we describe the procedure of producing xyloside-primed GAGs and how to study them structurally by disaccharide analysis.

Arylsulfatase K inactivation causes mucopolysaccharidosis due to deficient glucuronate desulfation of heparan and chondroitin sulfate

Mucopolysaccharidoses comprise a group of rare metabolic diseases, in which the lysosomal degradation of glycosaminoglycans (GAGs) is impaired due to genetically inherited defects of lysosomal enzymes involved in GAG catabolism. The resulting intralysosomal accumulation of GAG-derived metabolites consequently manifests in neurological symptoms and also peripheral abnormalities in various tissues like liver, kidney, spleen and bone. As each GAG consists of differently sulfated disaccharide units, it needs a specific, but also partly overlapping set of lysosomal enzymes to accomplish their complete degradation. Recently, we identified and characterized the lysosomal enzyme arylsulfatase K (Arsk) exhibiting glucuronate-2-sulfatase activity as needed for the degradation of heparan sulfate (HS), chondroitin sulfate (CS) and dermatan sulfate (DS). In the present study, we investigated the physiological relevance of Arsk by means of a constitutive Arsk knockout mouse model. A complete lack of glucuronate desulfation was demonstrated by a specific enzyme activity assay. Arsk-deficient mice show, in an organ-specific manner, a moderate accumulation of HS and CS metabolites characterized by 2-O-sulfated glucuronate moieties at their non-reducing ends. Pathophysiological studies reflect a rather mild phenotype including behavioral changes. Interestingly, no prominent lysosomal storage pathology like bone abnormalities were detected. Our results from the Arsk mouse model suggest a new although mild form of mucopolysacharidose (MPS), which we designate MPS type IIB.

Initial interaction of citrate-coated iron oxide nanoparticles with the glycocalyx of THP-1 monocytes assessed by real-time magnetic particle spectroscopy and electron microscopy

Interaction with biological material can alter physicochemical parameters of magnetic nanoparticles and might thereby change their magnetic behavior with potentially important implications for various nanoparticle applications. Little is known about changes of the magnetic behavior that occur during the initial phase of cell binding and uptake. We investigate the magnetic behavior of very small superparamagnetic iron-oxide nanoparticles (VSOP) during initial contact with THP-1 monocytes. We combine real-time magnetic particle spectroscopy (MPS), a fast and sensitive method for specific detection of magnetic nanoparticles in biological specimen with high-pressure-freezing/freeze-substitution transmission electron microscopy (HPF/FS-TEM), enabling us to generate snapshots of the interaction of VSOP with the cellular glycocalyx. MPS reveals significant changes of the dynamic magnetic behavior within seconds after VSOP injection into monocyte suspensions that correlate with the formation of nanoparticle clusters in the glycocalyx. The combination of real-time MPS and HPF/FS-TEM provides an ideal platform to analyze magnetic behaviors of nanoparticles upon interaction with cells and tissues.

A guide to hyaluronan and related enzymes in breast cancer: biological significance and diagnostic value

Hyaluronan (HA) is a unique nonsulfated glycosaminoglycan that contributes to breast cancer cells growth and functional properties, including cell migration, invasion, adhesion, as well as tumor-associated angiogenesis in different stages of breast cancer progression and especially metastasis. Latest data show that the levels of HA and/or low molecular mass HA in blood serum and plasma of breast cancer patients may be a useful biomarker for breast cancer prognosis, differential diagnosis, and patients' treatment monitoring. Therefore, the qualitative and quantitative determination of HA in biological samples is an emerging area of research. This review gathers, categorizes, and sums up all the currently used methodologies to analyze HA and HA-related enzymes. The advantages, disadvantages, limitations in use, and the information they provide, are critically considered and discussed. Moreover, emphasis is given to the significance of HA determination in breast cancer, as well as of its related enzymes, for diagnosis and prognosis of this type of cancer.

Role of syndecan-1 and exogenous heparin in hepatoma sphere formation

Glycosaminoglycan-modified proteoglycans play important roles in many cell activities, including cell differentiation and stem cell development. Tumor sphere formation ability is one of properties in cancer stem cells (CSCs). The correlation between CSC markers and proteoglycan remains to be clarified. Upon hepatoma sphere formation, expression of CSC markers CD13, CD90, CD133, and CD44, as well the syndecan family protein syndecan-1 (SDC1), increased as analyzed by PCR. Further examination by suppression of CD13 expression showed downregulation of SDC1 and CD44 gene expression, whereas suppression of SDC1 gene expression downregulated CD13 and CD44 gene expression. Suppression of SDC1 gene expression also suppressed sphere development, as analyzed by a novel sphereocrit assay to quantify the level of sphere formation. The heparin disaccharide components, but not those of chondroitin disaccharide, changed with hepatoma sphere development, revealing the increased levels of N-sulfation and 2-O-sulfation. These explained the inhibition of hepatoma sphere formation by exogenous heparin. In conclusion, we found that SDC1 affected CSC marker CD13 and CD44 expression. SDC1 proteoglycan and heparin components changed and affected hepatoma sphere development. Application of heparin mimics in reduction of hepatoma stem cells might be possible.

Factor H C-Terminal Domains Are Critical for Regulation of Platelet/Granulocyte Aggregate Formation

Platelet/granulocyte aggregates (PGAs) increase thromboinflammation in the vasculature, and PGA formation is tightly controlled by the complement alternative pathway (AP) negative regulator, Factor H (FH). Mutations in FH are associated with the prothrombotic disease atypical hemolytic uremic syndrome (aHUS), yet it is unknown whether increased PGA formation contributes to the thrombosis seen in patients with aHUS. Here, flow cytometry assays were used to evaluate the effects of aHUS-related mutations on FH regulation of PGA formation and characterize the mechanism. Utilizing recombinant fragments of FH spanning the entire length of the protein, we mapped the regions of FH most critical for limiting AP activity on the surface of isolated human platelets and neutrophils, as well as the regions most critical for regulating PGA formation in human whole blood stimulated with thrombin receptor-activating peptide (TRAP). FH domains 19–20 were the most critical for limiting AP activity on platelets, neutrophils, and at the platelet/granulocyte interface. The role of FH in PGA formation was attributed to its ability to regulate AP-mediated C5a generation. AHUS-related mutations in domains 19–20 caused differential effects on control of PGA formation and AP activity on platelets and neutrophils. Our data indicate FH C-terminal domains are key for regulating PGA formation, thus increased FH protection may have a beneficial impact on diseases characterized by increased PGA formation, such as cardiovascular disease. Additionally, aHUS-related mutations in domains 19–20 have varying effects on control of TRAP-mediated PGA formation, suggesting that some, but not all, aHUS-related mutations may cause increased PGA formation that contributes to excessive thrombosis in patients with aHUS.

Sequencing of glycosaminoglycans with potential to interrogate sequence-specific interactions

Technologies to sequence nucleic acids/proteins are widely available, but straightforward methodologies to sequence complex polysaccharides are lacking. We here put forward a strategy to sequence glycosaminoglycans, long linear polysaccharides involved in many biochemical processes. The method is based on the covalent immobilization and (immuno)chemical characterization of only those size-separated saccharides that harbor the original reducing end of the full-length chain. Using this methodology, the saccharide sequence of the chondroitin sulfate chain of the proteoglycan bikunin was determined. The method can be performed in any standard biochemical lab and opens studies to the interaction of complex saccharide sequences with other biomolecules.

A common sugar-nucleotide-mediated mechanism of inhibition of (glycosamino)glycan biosynthesis, as evidenced by 6F-GalNAc (Ac3)

Glycosaminoglycan (GAG) polysaccharides have been implicated in a variety of cellular processes, and alterations in their amount and structure have been associated with diseases such as cancer. In this study, we probed 11 sugar analogs for their capacity to interfere with GAG biosynthesis. One analog, with a modification not directly involved in the glycosidic bond formation, 6F-N-acetyl-d-galactosamine (GalNAc) (Ac3), was selected for further study on its metabolic and biologic effect. Treatment of human ovarian carcinoma cells with 50 μM 6F-GalNAc (Ac3) inhibited biosynthesis of GAGs (chondroitin/dermatan sulfate by ∼50-60%, heparan sulfate by ∼35%), N-acetyl-d-glucosamine (GlcNAc)/GalNAc containing glycans recognized by the lectins Datura stramonium and peanut agglutinin (by ∼74 and ∼43%, respectively), and O-GlcNAc protein modification. With respect to function, 6F-GalNAc (Ac3) treatment inhibited growth factor signaling and reduced in vivo angiogenesis by ∼33%. Although the analog was readily transformed in cells into the uridine 5'-diphosphate (UDP)-activated form, it was not incorporated into GAGs. Rather, it strongly reduced cellular UDP-GalNAc and UDP-GlcNAc pools. Together with data from the literature, these findings indicate that nucleotide sugar depletion without incorporation is a common mechanism of sugar analogs for inhibiting GAG/glycan biosynthesis.

Determination of the unsaturated disaccharides of hyaluronic acid in equine synovial fluid by high-performance liquid chromatography and fluorescence detection

Background

The purpose of this study was to develop and validate an analytical method to determine the presence of hyaluronic acid derived disaccharides in equine synovial fluid.

Findings

A high-performance liquid chromatography method for the determination of hyaluronic acid derived unsaturated disaccharides in equine synovial fluid was developed and validated. The method is based on the measurement of unsaturated disaccharides released by digestion of linear hyaluronic acid molecules. The method showed linearity (r² = 0.996) over the full working concentration range 0.89-30 mg/l. Relative standard deviation of intra- and inter-day precision ranged from of 4.3-6.7% and 7.1-7.8% respectively. The detection limit was 0.3 mg/l corresponding to 20 mg/l in synovial fluid. Accuracy of the assay was 97-103%. This method was evaluated by determining the concentration of unsaturated disaccharides from hyaluronic acid in synovial fluid of horses with lameness in the metacarpo-/metatarsophalangeal joint localized with positive response to intra-articular anesthesia.

Conclusions

The described method is valid for determination of hyaluronic acid derived disaccharides in equine synovial fluid. This method was applied to a larger research project dealing with a new form of intra-articular therapy in horses with arthritic diseases.

FACE analysis as a fast and reliable methodology to monitor the sulfation and total amount of chondroitin sulfate in biological samples of clinical importance

Glycosaminoglycans (GAGs) due to their hydrophilic character and high anionic charge densities play important roles in various (patho)physiological processes. The identification and quantification of GAGs in biological samples and tissues could be useful prognostic and diagnostic tools in pathological conditions. Despite the noteworthy progress in the development of sensitive and accurate methodologies for the determination of GAGs, there is a significant lack in methodologies regarding sample preparation and reliable fast analysis methods enabling the simultaneous analysis of several biological samples. In this report, developed protocols for the isolation of GAGs in biological samples were applied to analyze various sulfated chondroitin sulfate- and hyaluronan-derived disaccharides using fluorophore-assisted carbohydrate electrophoresis (FACE). Applications to biologic samples of clinical importance include blood serum, lens capsule tissue and urine. The sample preparation protocol followed by FACE analysis allows quantification with an optimal linearity over the concentration range 1.0–220.0 µg/mL, affording a limit of quantitation of 50 ng of disaccharides. Validation of FACE results was performed by capillary electrophoresis and high performance liquid chromatography techniques.

Circulating glycosaminoglycan species in septic shock

BACKGROUND

Glycosaminoglycans (GAGs) are negatively charged polysaccharides present, e.g., on the luminal face of the blood vessels as heparan sulphate (HS) and hyaluronic acid (HA), in the interstitium as HA, and in neutrofils and plasma as chondroitin sulphate (CS) and HA. Total plasma levels of GAG are increased in human septic shock, but the origin and pathophysiological implications are unclear. In order to determine the source of circulating GAG in sepsis, we compared plasma levels of HS, HA, CS and keratan sulphate (KS) in patients with septic shock and controls.

METHODS

HS and KS were measured with enzyme-linked immunosorbent assay, and HA and CS disaccharides with liquid chromatography tandem mass spectrometry in plasma obtained from patients admitted to intensive care fulfilling criteria for septic shock as well as from matched control patients scheduled for neurosurgery.

RESULTS

Median levels of HS and HA were fourfold increased in septic shock and were higher in patients that did not survive 90 days (threefold and fivefold for HS and HA, respectively). Median CS levels were unaltered, while KS levels were slightly decreased in sepsis patients. HS and HA levels correlated with levels of interleukin-6 and interleukin-10. Except for HA, GAG levels did not correlate to liver or kidney sequential organ function score.

CONCLUSION

Median plasma level of HS and HA is increased in septic shock patients, are higher in patients that do not survive, and correlates with inflammatory activation and failing circulation. The increased levels could be due to vascular damage.

Method development and analysis of free HS and HS in proteoglycans from pre- and postmenopausal women: evidence for biosynthetic pathway changes in sulfotransferase and sulfatase enzymes

Heparan sulfate (HS) is one of the most complex and informative biopolymers found on the cell surface or in the extracellular matrix as either free HS fragments or constituents of HS proteoglycans (HSPGs). Analysis of free HS and HSPG sugar chains in human serum at the disaccharide level has great potential for early disease diagnosis and prognosis; however, the low concentration of HS in human serum, together with the complexity of the serum matrix, limits the information on HS. In this study, we present and validate the development of a new sensitive method for in-depth compositional analysis of free HS and HSPG sugar chains. This protocol involved several steps including weak anion exchange chromatography, ultrafiltration, and solid-phase extraction for enhanced detection prior to LC-MS/MS analysis. Using this protocol, a total of 51 serum samples from 26 premenopausal and 25 postmenopausal women were analyzed. Statistically significant differences in heparin/HS disaccharide profiles were observed. The proportion of N-acetylation and N-sulfation in both free HS and HSPG sugar chains were significantly different between pre- and postmenopausal women, indicating changes in N-deacetylase/N-sulfotransferases (NDSTs), the enzymes involved in the initial step of the biosynthetic pathway. Differences in the proportion of 6-O-sulfation suggest that 6-O-sulfotransferase and/or 6-O-sulfatase enzymes may also be implicated.

Extraction and structural analysis of glycosaminoglycans from formalin-fixed, paraffin-embedded tissues

Glycosaminoglycans (GAGs) are long, anionic polysaccharides involved in many basic aspects of mammalian physiology and pathology. Here we describe a method to extract GAGs from formalin-fixed, paraffin-embedded tissues and found that they are structurally comparable with GAGs extracted from frozen tissues. We employed this method to structurally characterize GAGs in tissues, including laser-dissected layers of skin and pathological specimens. This method enables the use of the archival paraffin-embedded material for detailed (structural) analysis of GAGs.

Cell-Based Microscale Isolation of Glycoaminoglycans for Glycomics Study

Glycomics research requires the isolation of glycans from cells for structural characterization and functional studies of the glycans. A method for cell-based microscale isolation and quantification of highly sulfated, moderately sulfated, and nonsulfated glycosaminoglycans (GAGs) was developed using Chinese hamster ovary (CHO) cells. This microscale isolation relies on a mini-strong anion exchange spin column eluted stepwise with different concentrations of sodium chloride solution. Hyaluronic acid, chondroitin sulfate, and heparin were used to optimize the isolation of the endogenous glycosaminoglycans in CHO cells. This method can also be used to determine the presence of nonsulfated GAGs including heparosan, hyaluronic acid, and nonsulfated chondroitin.

Analysis of glycosaminoglycan-derived disaccharides by capillary electrophoresis using laser-induced fluorescence detection

A quantitative and highly sensitive method for the analysis of glycosaminoglycan (GAG)-derived disaccharides that relies on capillary electrophoresis (CE) with laser-induced fluorescence detection is presented. This method enables complete separation of 17 GAG-derived disaccharides in a single run. Unsaturated disaccharides were derivatized with 2-aminoacridone to improve sensitivity. The limit of detection was at the attomole level and approximately 100-fold more sensitive than traditional CE-ultraviolet detection. A CE separation timetable was developed to achieve complete resolution and shorten analysis time. The relative standard deviations of migration time and peak areas at both low and high concentrations of unsaturated disaccharides are all less than 2.7 and 3.2%, respectively, demonstrating that this is a reproducible method. This analysis was successfully applied to cultured Chinese hamster ovary cell samples for determination of GAG disaccharides. The current method simplifies GAG extraction steps and reduces inaccuracy in calculating ratios of heparin/heparan sulfate to chondroitin sulfate/dermatan sulfate resulting from the separate analyses of a single sample.

Disaccharide analysis of glycosaminoglycan mixtures by ultra-high-performance liquid chromatography-mass spectrometry

Glycosaminoglycans are a family of polysaccharides widely distributed in all eukaryotic cells. These polyanionic, linear chain polysaccharides are composed of repeating disaccharide units that are often differentially substituted with sulfo groups. The diversity of glycosaminoglycan structures in cells, tissues and among different organisms reflect their functional an evolutionary importance. Glycosaminoglycan composition and structure also changes in development, aging and in disease progression, making their accurate and reliable analysis a critical, albeit, challenging endeavor. Quantitative disaccharide compositional analysis is one of the primary ways to characterize glycosaminoglycan composition and structure and has a direct relationship with glycosaminoglycan biological functions. In this study, glycosaminoglycan disaccharides, prepared from heparan sulfate/heparin, chondroitin sulfate/dermatan sulfate and neutral hyaluronic acid using multiple polysaccharide lyases, were fluorescently labeled with 2-aminoacridone, fractionated into 17 well-resolved components by reverse-phase ultra-performance liquid chromatography, and analyzed by electrospray ionization mass spectrometry. This analysis was successfully applied to cell, tissue, and biological fluid samples for the picomole level detection of glycosaminoglycan composition and structure.

Combining size-exclusion chromatography and fully automated chip-based nanoelectrospray quadrupole time-of-flight tandem mass spectrometry for structural analysis of chondroitin/dermatan sulfate in human decorin

Chondroitin/dermatan sulfate (CS/DS) chain of decorin (DCN) from human skin fibroblasts (HSk) was released by reductive β-elimination reaction and digested with chondroitin AC I lyase. Enzymatic hydrolysis mixture of CS/DS chains was separated by size-exclusion chromatography (SEC). Collected octasaccharide fraction was subjected to fully automated chip-based nanoelectrospray (nanoESI) quadrupole time-of-flight (QTOF) MS and tandem MS (MS/MS). MS of human skin fibroblasts DCN CS/DS displayed a high complexity due to the large variety of glycoforms, which under chip-nanoESI MS readily ionized to form multiply charged ions. Except for the regularly tetrasulfated octasaccharide, the investigated fraction contained four additional octasaccharides of atypical sulfation status. Two new oversulfated glycoforms and two undersulfated species were identified. Remarkably, the series of decasaccharides discovered in the same SEC pool was found to encompass a trisulfated and a novel hexasulfated [4,5-Δ-GlcAGalNAc(IdoAGalNAc)⁴] species. MS/MS by collision-induced dissociation (CID) on the [M-4H]⁴ ion corresponding to the previously not reported [4,5-Δ-GlcAGalNAc(IdoAGalNAc)₃](5S) corroborated for a novel motif in which three N-acetylgalactosamine (GalNAc) moieties are monosulfated, 4,5-Δ-GlcA and the first IdoA from the non-reducing end bear one sulfate group each, while the second N-acetylgalactosamine from the reducing end is unsulfated.

A comprehensive compositional analysis of heparin/heparan sulfate-derived disaccharides from human serum

The analysis of heparan sulfate glycosaminoglycans (HSGAGs) variations in human serum at the disaccharide level has a great potential for disease diagnosis and prognosis. However, the lack of available analytical methodology for the compositional analysis of HSGAGs in human serum remains to be addressed to delineate the possible role of HSGAGs on the onset and/or progression of a disease. In this study, we have developed a method for the in-depth compositional analysis of the 12 heparin/HS-derived disaccharides from human serum using a combination of technologies--fractionation, exhaustive digestion, solid phase extraction, and LC-MS/MS. The method exhibits high recovery (72-110%) and good reproducibility (standard deviation of less than 5%) with a low limit of detection and quantification. Errors from the method validation were within 1.1%. Nondetectable non- or low-sulfated disaccharides in human serum were also detected using the optimized protocol. Further applying this method, the comprehensive analysis of HSGAGs compositions in human sera from female donors showed considerable variations in disaccharide patterns and compositions.

Microdetermination of hyaluronan in human plasma by high-performance liquid chromatography with a graphitized carbon column and postcolumn fluorometric detection

A chemical method for the determination of hyaluronan (hyaluronic acid, HA) has been developed and applied to the human blood plasma. Human blood plasma HA was converted to the ΔDi-HA by digestion with hyaluronidase SD and determined by a sensitive and selective high-performance liquid chromatography (HPLC). The HPLC includes the separation and detection of ΔDi-HA using a graphitized carbon column and fluorometric reaction with 2-cyanoacetamide in an alkaline eluent. The calibration graph for ΔDi-HA was linear over the range 0.2 ng-1 μg. It was revealed that the concentration of HA in normal human blood plasma is very low levels (about 24 ng/ml) in comparison to low-sulfated chondroitin 4-sulfate (about 13 μg/ml).

Modern developments in mass spectrometry of chondroitin and dermatan sulfate glycosaminoglycans

Chondroitin sulfate (CS) and dermatan sulfate (DS) are special types of glycosaminoglycan (GAG) oligosaccharides able to regulate vital biological functions that depend on precise motifs of their constituent hexose sequences and the extent and location of their sulfation. As a result, the need for better understanding of CS/DS biological role called for the elaboration and application of straightforward strategies for their composition and structure elucidation. Due to its high sensitivity, reproducibility, and the possibility to rapidly generate data on fine CS/DS structure determinants, mass spectrometry (MS) based on either electrospray ionization (ESI) or matrix-assisted laser desorption/ionization (MALDI) brought a major progress in the field. Here, modern developments in MS of CS/DS GAGs are gathered in a critical review covering the past 5 years. The first section is dedicated to protocols for CS/DS extraction from parent proteoglycan, digestion, and purification that are among critical prerequisites of a successful MS experiment. The second part highlights several MALDI MS aspects, the requirements, and applications of this ionization method to CS/DS investigation. An ample chapter is devoted to ESI MS strategies, which employ either capillary- or advanced chip-based sample infusion in combination with multistage MS (MS(n)) using either collision-induced (CID) or electron detachment dissociation (EDD). At last, the potential of two versatile separation techniques, capillary electrophoresis (CE), and liquid chromatography (LC) in off- and/or on-line coupling with ESI MS and MS(n), is discussed, alongside an assessment of particular buffer/solvent conditions and instrumental parameters required for CS/DS mixture separation followed by on-line mass analysis of individual components.

High-performance liquid chromatography and on-line mass spectrometry detection for the analysis of chondroitin sulfates/hyaluronan disaccharides derivatized with 2-aminoacridone

In this study, we developed an on-line reverse-phase high-performance liquid chromatography-electrospray ionization-mass spectrometry (RP-HPLC-ESI-MS) separation and structural characterization of hyaluronan (HA)/chondroitin sulfate (CS)/dermatan sulfate (DS) disaccharides released by enzymatic treatment and derivatized with 2-aminoacridone (AMAC), providing a high-resolution system also applicable by using a further fluorimetric detector (Fp) before ESI-MS spectral acquisition. Isomeric nonsulfated HA and CS/DS disaccharides, isomeric monosulfated and isomeric disulfated CS/DS disaccharides, and the trisulfated species were distinctly separated and unambiguously identified by their retention times and mass spectra in negative ionization mode. In general, no multiply charged ions were detected even for highly charged disaccharides, but the presence of desulfonated products for highly sulfated species due to the relative instability of sulfo groups was observed. RP-HPLC-ESI-MS of each AMAC disaccharide was found to be linear from 3 to 500 ng with very high coefficient of correlation values due to the high efficiency of separation and the sharp outline of the peaks. Various CS/DS samples were characterized for disaccharide composition, and minor oligomer species identified as GalNAcSO(4) at the nonreducing end of chains was observed as a common component of these macromolecules. Furthermore, purified endogenous normal human plasma CS disaccharides were also evaluated by means of RP-HPLC-(Fp)-ESI-MS.

Quantitative determination and comparison of the glycosaminoglycan Delta-disaccharide composition in 22 different human cell lines

Changes in proteoglycan and glycosaminoglycan (GAG) content and distribution may play an important role in the development of many diseases, atherosclerosis, cancer and diabetes. Human cell lines act as models for the underlying pathomechanisms. Despite the importance of proteoglycans for cell functioning, information on the GAG composition of most human cell lines is limited. Comparative analysis of the GAG Deltadisaccharide amount in 22 human cell lines yielded a mean value of 94 +/- 58 pmol/10(6) cells (mean+/-SEM). Total GAG amount and heparan sulfate/heparin Deltadisaccharide composition, but not chondroitin sulfate/dermatan sulfate Deltadisaccharide composition, differed significantly between the investigated adherent and suspension cell lines. We provide a novel overview of GAG Deltadisaccharide composition in 22 different human cell lines.

The xylosyltransferase Iota gene polymorphism c.343G>T (p.A115S) is associated with decreased serum glycosaminoglycan levels

OBJECTIVES

The xylosyltransferases I and II (XT-I, XT-II, EC 2.4.2.26) are the chain-initiating enzymes in the biosynthesis of glycosaminoglycans (GAGs). This is the first investigation of changes in the serum GAG amount and composition in association with polymorphisms in XYLT1 and XYLT2.

DESIGN AND METHODS

Genotyping of three genetic variations in the genes XYLT1 and XYLT2 was performed in 223 healthy blood donor samples. Serum samples were analyzed for their GAG Delta-disaccharide content by reversed-phase high-performance liquid chromatography (RP-HPLC). Furthermore serum XT activity was determined by a radiochemical assay.

RESULTS

The single nucleotide polymorphism (SNP) c.343G>T in XYLT1 exon 1 correlated with a significantly decreased GAG content in the serum (p<0.01). For the other two investigated XYLT2 variations (c.166G>A in exon 2 and c.1253C>T in exon 6) no changes in the serum GAG amount were detected. No investigated SNPs were associated with changes to serum XT activities.

CONCLUSIONS

The XYLT1 SNP c.343G>T is associated with a decreased GAG amount in the serum of healthy blood donors.