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The roles of keratan sulfate (KS) as a proton detection glycosaminoglycan in neurosensory processes in the central and peripheral nervous systems is reviewed. The functional properties of the KS-proteoglycans aggrecan, phosphacan, podocalyxcin as components of perineuronal nets in neurosensory processes in neuronal plasticity, cognitive learning and memory are also discussed. KS-glycoconjugate neurosensory gels used in electrolocation in elasmobranch fish species and KS substituted mucin like conjugates in some tissue contexts in mammals need to be considered in sensory signalling. Parallels are drawn between KS's roles in elasmobranch fish neurosensory processes and its roles in mammalian electro mechanical transduction of acoustic liquid displacement signals in the cochlea by the tectorial membrane and stereocilia of sensory inner and outer hair cells into neural signals for sound interpretation. The sophisticated structural and functional proteins which maintain the unique high precision physical properties of stereocilia in the detection, transmittance and interpretation of acoustic signals in the hearing process are important. The maintenance of the material properties of stereocilia are essential in sound transmission processes. Specific, emerging roles for low sulfation KS in sensory bioregulation are contrasted with the properties of high charge density KS isoforms. Some speculations are made on how the molecular and electrical properties of KS may be of potential application in futuristic nanoelectronic, memristor technology in advanced ultrafast computing devices with low energy requirements in nanomachines, nanobots or molecular switches which could be potentially useful in artificial synapse development. Application of KS in such innovative areas in bioregulation are eagerly awaited. [ABSTRACT FROM AUTHOR]

We recently showed that 6-sulfo sialyl N-acetyllactosamine (LacNAc) in O-linked glycans recognized by the CL40 antibody is abundant in the pleural mesothelium under physiological conditions and that these glycans undergo complementary synthesis by GlcNAc6ST2 (encoded by Chst4) and GlcNAc6ST3 (encoded by Chst5) in mice. GlcNAc6ST3 is essential for the synthesis of R-10G-positive keratan sulfate (KS) in the brain. The predicted minimum epitope of the R-10G antibody is a dimeric asialo 6-sulfo LacNAc. Whether R-10G-reactive KS/sulfated LacNAc oligosaccharides are also present in the pleural mesothelium was unknown. The question of which GlcNAc6STs are responsible for R-10G-reactive glycans was an additional issue to be clarified. Here, we show that R-10G-reactive glycans are as abundant in the pulmonary pleura as CL40-reactive glycans and that GlcNAc6ST3 is only partially involved in the synthesis of these pleural R-10G glycans, unlike in the adult brain. Unexpectedly, GlcNAc6ST2 is essential for the synthesis of R-10G-positive KS/sulfated LacNAc oligosaccharides in the lung pleura. The type of GlcNAc6ST and the magnitude of its contribution to KS glycan synthesis varied among tissues in vivo. We show that GlcNAc6ST2 is required and sufficient for R-10G-reactive KS synthesis in the lung pleura. Interestingly, R-10G immunoreactivity in KSGal6ST (encoded by Chst1) and C6ST1 (encoded by Chst3) double-deficient mouse lungs was markedly increased. MUC16, a mucin molecule, was shown to be a candidate carrier protein for pleural R-10G-reactive glycans. These results suggest that R-10G-reactive KS/sulfated LacNAc oligosaccharides may play a role in mesothelial cell proliferation and differentiation. Further elucidation of the functions of sulfated glycans synthesized by GlcNAc6ST2 and GlcNAc6ST3, such as R-10G and CL40 glycans, in pathological conditions may lead to a better understanding of the underlying mechanisms of the physiopathology of the lung mesothelium. [ABSTRACT FROM AUTHOR]

Macular corneal dystrophy (MCD) is a progressive, bilateral stromal dystrophic disease that arises from mutations in carbohydrate sulfotransferase 6 (CHST6). Corneal transplantation is the ultimate therapeutic solution for MCD patients. Unfortunately, postoperative recurrence remains a significant challenge. We conducted a retrospective review of a clinical cohort comprising 102 MCD patients with 124 eyes that underwent either penetrating keratoplasty (PKP) or deep anterior lamellar keratoplasty (DALK). Our results revealed that the recurrence rate was nearly three times higher in the DALK group (39.13%, 9/23 eyes) compared with the PKP group (10.89%, 11/101 eyes), suggesting that surgical replacement of the corneal endothelium for treating MCD is advisable to prevent postoperative recurrence. Our experimental data confirmed the robust mRNA and protein expression of CHST6 in human corneal endothelium and the rodent homolog CHST5 in mouse endothelium. Selective knockdown of wild-type Chst5 in mouse corneal endothelium (ACsiChst5), but not in the corneal stroma, induced experimental MCD with similar extracellular matrix synthesis impairments and corneal thinning as observed in MCD patients. Mice carrying Chst5 point mutation also recapitulated clinical phenotypes of MCD, along with corneal endothelial abnormalities. Intracameral injection of wild-type Chst5 rescued the corneal impairments in ACsiChst5 mice and retarded the disease progression in Chst5 mutant mice. Overall, our study provides new mechanistic insights and therapeutic approaches for MCD treatment by high-lighting the role of corneal endothelium in MCD development. [ABSTRACT FROM AUTHOR]

A sulfated polysaccharide (AG) was extracted and isolated from the sea cucumber H. fuscopunctata, consisting of GlcNAc, GalNAc, Gal, Fuc and lacking any uronic acid residues. Importantly, several chemical depolymerization methods were used to elucidate the structure of the AG through a bottom-up strategy. A highly sulfated galactose (oAG-1) and two disaccharides labeled with 2,5-anhydro-D-mannose (oAG-2, oAG-3) were obtained from the deaminative depolymerized product along with the structures of the disaccharide derivatives (oAG-4~oAG-6) identified from the free radical depolymerized product, suggesting that the repeating building blocks in a natural AG should comprise the disaccharide β-D-GalS-1,4-D-GlcNAc6S. The possible disaccharide side chains (bAG-1) were obtained with mild acid hydrolysis. Thus, a natural AG may consist of a keratan sulfate-like (KS-like) glycosaminoglycan with diverse modifications, including the sulfation types of the Gal residue and the possible disaccharide branches α-D-GalNAc4S6S-1,2-α/β-L-Fuc3S linked to the KS-like chain. Additionally, the anticoagulant activities of the AG and its depolymerized products (dAG1-9) were evaluated in vitro using normal human plasma. The AG could prolong activated partial thromboplastin time (APTT) in a dose-dependent manner, and the activity potency was positively related to the chain length. The AG and dAG1-dAG3 could prolong thrombin time (TT), while they had little effect on prothrombin time (PT). The results indicate that the AG could inhibit the intrinsic and common coagulation pathways. [ABSTRACT FROM AUTHOR]

Thus far, several monoclonal antibodies directed against cell-surface carbohydrate antigens have been generated. Among them, R-10G reportedly reacts selectively with human embryonic stem and induced pluripotent stem cells, but not with embryonal carcinoma (EC) cells. However, EC cells derived from patients' EC tumors may exhibit varying levels of R-10G-reactive antigen expression. Thus, we asked whether human EC tissues or germ cell tumor (GCT) tissues other than EC express R-10G-reactive antigen. To do so, we quantitatively analyzed R-10G-reactive antigen expression in 83 testicular GCT surgical specimens containing a total of 125 various GCT components. Accordingly, in all EC components examined, the EC cell plasma membrane was immunolabeled with R-10G, while most seminoma components were R-10G-negative. In non-seminomatous GCT (NSGCT) other than EC (non-EC NSGCT), R-10G-reactive antigen expression was variable, but signal distribution was focal, and the average intensity was weaker than that seen in EC. The percentages of R-10G-positive cells in these three groups varied with high statistical significance (p <0.001 for all combinations). These findings indicate that the R-10G-reactive antigen is preferentially expressed in human testicular EC tissues and, thus, could be used as a diagnostic marker for this malignancy. [ABSTRACT FROM AUTHOR]

Glycosaminoglycans are native components of the extracellular matrix that drive cell behavior and control the microenvironment surrounding cells, making them promising therapeutic targets for a myriad of diseases. Recent studies have shown that recapitulation of cell interactions with the extracellular matrix are key in tissue engineering, where the aim is to mimic and regenerate endogenous tissues. Because of this, incorporation of glycosaminoglycans to drive stem cell fate and promote cell proliferation in engineered tissues has gained increasing attention. This review summarizes the role glycosaminoglycans can play in tissue engineering and the recent advances in their use in these constructs. We also evaluate the general trend of research in this niche and provide insight into its future directions.

Glycosaminoglycans are native components of the extracellular matrix that drive cell behavior and control the microenvironment surrounding cells, making them promising therapeutic targets for a myriad of diseases. Recent studies have shown that recapitulation of cell interactions with the extracellular matrix are key in tissue engineering, where the aim is to mimic and regenerate endogenous tissues. Because of this, incorporation of glycosaminoglycans to drive stem cell fate and promote cell proliferation in engineered tissues has gained increasing attention. This review summarizes the role glycosaminoglycans can play in tissue engineering and the recent advances in their use in these constructs. We also evaluate the general trend of research in this niche and provide insight into its future directions.

We recently showed that 6-sulfo sialyl N-acetyllactosamine (LacNAc) in O-linked glycans recognized by the CL40 antibody is abundant in the pleural mesothelium under physiological conditions and that these glycans undergo complementary synthesis by GlcNAc6ST2 (encoded by Chst4) and GlcNAc6ST3 (encoded by Chst5) in mice. GlcNAc6ST3 is essential for the synthesis of R-10G-positive keratan sulfate (KS) in the brain. The predicted minimum epitope of the R-10G antibody is a dimeric asialo 6-sulfo LacNAc. Whether R-10G-reactive KS/sulfated LacNAc oligosaccharides are also present in the pleural mesothelium was unknown. The question of which GlcNAc6STs are responsible for R-10G-reactive glycans was an additional issue to be clarified. Here, we show that R-10G-reactive glycans are as abundant in the pulmonary pleura as CL40-reactive glycans and that GlcNAc6ST3 is only partially involved in the synthesis of these pleural R-10G glycans, unlike in the adult brain. Unexpectedly, GlcNAc6ST2 is essential for the synthesis of R-10G-positive KS/sulfated LacNAc oligosaccharides in the lung pleura. The type of GlcNAc6ST and the magnitude of its contribution to KS glycan synthesis varied among tissues in vivo. We show that GlcNAc6ST2 is required and sufficient for R-10G-reactive KS synthesis in the lung pleura. Interestingly, R-10G immunoreactivity in KSGal6ST (encoded by Chst1) and C6ST1 (encoded by Chst3) double-deficient mouse lungs was markedly increased. MUC16, a mucin molecule, was shown to be a candidate carrier protein for pleural R-10G-reactive glycans. These results suggest that R-10G-reactive KS/sulfated LacNAc oligosaccharides may play a role in mesothelial cell proliferation and differentiation. Further elucidation of the functions of sulfated glycans synthesized by GlcNAc6ST2 and GlcNAc6ST3, such as R-10G and CL40 glycans, in pathological conditions may lead to a better understanding of the underlying mechanisms of the physiopathology of the lung mesothelium.

Glycosaminoglycan is a generic term for a class of minor but significant components of the body. The extraction, application, and functionalization of GAGs are essential to explore owing to their biological significance. The extraction of GAGs from different species, such as vertebrates, invertebrates, molluscs, and marine sources, is discussed. The present review focuses on the GAGs extraction and purification by various techniques like spectroscopic, chromatographic, and enzymatic methods. The review also emphasizes the functionalities of glycosaminoglycans and their mode of interaction with the protein moiety for their physiological functions. The industrial applications of GAGs in various areas, such as cosmetics, medicine, biotechnology, food, and textiles, have also been reported in the present review.

A sulfated polysaccharide (AG) was extracted and isolated from the sea cucumber H. fuscopunctata, consisting of GlcNAc, GalNAc, Gal, Fuc and lacking any uronic acid residues. Importantly, several chemical depolymerization methods were used to elucidate the structure of the AG through a bottom-up strategy. A highly sulfated galactose (oAG-1) and two disaccharides labeled with 2,5-anhydro-D-mannose (oAG-2, oAG-3) were obtained from the deaminative depolymerized product along with the structures of the disaccharide derivatives (oAG-4~oAG-6) identified from the free radical depolymerized product, suggesting that the repeating building blocks in a natural AG should comprise the disaccharide β-D-GalS-1,4-D-GlcNAc6S. The possible disaccharide side chains (bAG-1) were obtained with mild acid hydrolysis. Thus, a natural AG may consist of a keratan sulfate-like (KS-like) glycosaminoglycan with diverse modifications, including the sulfation types of the Gal residue and the possible disaccharide branches α-D-GalNAc4S6S-1,2-α/β-L-Fuc3S linked to the KS-like chain. Additionally, the anticoagulant activities of the AG and its depolymerized products (dAG1-9) were evaluated in vitro using normal human plasma. The AG could prolong activated partial thromboplastin time (APTT) in a dose-dependent manner, and the activity potency was positively related to the chain length. The AG and dAG1-dAG3 could prolong thrombin time (TT), while they had little effect on prothrombin time (PT). The results indicate that the AG could inhibit the intrinsic and common coagulation pathways.

The innate negative charge of glycosaminoglycans (GAG) is in the origin of their bioactivity: it drives their spontaneous complexation with positively charged biomolecules and ions, regulating homeostatic functions by protein stabilization, protection and activation. Copycatting these interactions enables different supramolecular approaches towards the assembly of biofunctional devices. Such approaches allow processing under physiological conditions and thus, they are of unprecedented biocompliance for device build-up compared to conventional methods based on chemical cross-linkers, volatile and organic solvents, and high temperatures. We review different set-ups based on GAG electrostatic complexation and showcase their application towards the development of diverse therapeutic systems. We also discuss challenges associated with GAG complexation into intricate three-dimensional networks holding back the widespread use of these methods. Finally, we anticipate that conscious choice of GAG with distinct polyanionic strength and specific bioactivity will make possible the fabrication of constructs with personalized and customized properties in the nearest future. [ABSTRACT FROM AUTHOR]

Mammals express a wide variety of glycans that include N‐glycans, O‐glycans, proteoglycans, glycolipids, etc. Glycan expression can modulate the cellular functions, and hence is strongly involved in the onset and progression of numerous diseases. Here, we report the relevance of the ectopic expression of keratan sulfate (KS) glycan chains in human malignant melanomas. Using a human melanoma cell line, we found that the KS enhanced the invasiveness of the cells but caused no change in the growth rate of the cells. The phosphorylation of paxillin, a focal adhesion‐associated adaptor protein, was strong at the region where KS was expressed in the melanoma tissues, indicating that KS stimulated the phosphorylation of paxillin. We also observed that KS enhanced the adhesion of melanoma cells and this was accompanied by a greatly increased level of phosphorylation of paxillin. These data suggest that the expression of KS contributes to the development of malignant phenotypes such as strong cell adhesion and the invasiveness of melanoma cells. [ABSTRACT FROM AUTHOR]

Objective: To reduce the risk of locoregional recurrence, the addition of neoadjuvant concurrent chemoradiotherapy (CCRT) is recommended before surgical management for rectal cancer patients. However, despite identical tumor histology, individual patient response to neoadjuvant CCRT varies greatly. Accordingly, a comprehensive molecular characterization that is used to predict CCRT efficacy is instantly needed.Methods: Pearson’s chi-squared test was utilized to correlate dehydrogenase/reductase 9 (DHRS9) expression with clinicopathological features. Survival curves were created applying the Kaplan-Meier method, and the log-rank test was conducted to compare prognostic utility between high and low DHRS9 expression groups. Multivariate Cox proportional hazards regression analysis was applied to identify independent prognostic biomarkers based on variables with prognostic utility at the univariate level.Results: Utilizing a public transcriptome dataset, we identified that the DHRS9 gene is the most considerably upregulated gene related to epithelial cell differentiation (GO: 0030855) among rectal cancer patients with CCRT resistance. Employing immunohistochemical staining, we also demonstrated that high DHRS9 immunoexpression is considerably associated with an aggressive clinical course and CCRT resistance in our rectal cancer cohort. Among all variables with prognostic utility at the univariate level, only high DHRS9 immunoexpression was independently unfavorably prognostic of all three endpoints (all p ≤ 0.048) in the multivariate analysis. In addition, applying bioinformatic analysis, we also linked DHRS9 with unrevealed functions, such as keratan sulfate and mucin synthesis which may be implicated in CCRT resistance.Conclusion: Altogether, DHRS9 expression may serve as a helpful predictive and prognostic biomarker and assist decision-making for rectal cancer patients who underwent neoadjuvant CCRT.

Human sialic acid-binding immunoglobulin-like lectins (Siglecs) are expressed on subsets of immune cells. Siglec-8 is an immune inhibitory Siglec on eosinophils and mast cells, which are effectors in allergic disorders including eosinophilic esophagitis. Inhibition occurs when Siglec-8 is crosslinked by multivalent Siglec ligands in target tissues. Previously we discovered a high-affinity Siglec-8 sialoglycan ligand on human airways composed of terminally sialylated keratan sulfate chains carried on a single protein, DMBT1. Here we extend that approach to another allergic inflammatory target tissue, human esophagus. Lectin overlay histochemistry revealed that Siglec-8 ligands are expressed predominantly by esophageal submucosal glands, and are densely packed in submucosal ducts leading to the lumen. Expression is tissue-specific; esophageal glands express Siglec-8 ligand whereas nearby gastric glands do not. Extraction and resolution by gel electrophoresis revealed a single predominant human esophageal Siglec-8 ligand migrating at >2 MDa. Purification by size exclusion and affinity chromatography, followed by proteomic mass spectrometry, revealed the protein carrier to be MUC5B. Whereas all human esophageal submucosal cells express MUC5B, only a portion convert it to Siglec-8 ligand by adding terminally sialylated keratan sulfate chains. We refer to this as MUC5B S8L. Material from the esophageal lumen of live subjects revealed MUC5B S8L species ranging from ~1-4 MDa. We conclude that MUC5B in the human esophagus is a protein canvas on which Siglec-8 binding sialylated keratan sulfate chains are post-translationally added. These data expand understanding of Siglec-8 ligands and may help us understand their roles in allergic immune regulation., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Abstract Background Morquio B disease (MBD) is a distinct GLB1‐related dysostosis multiplex presenting a mild phenocopy of GALNS‐related Morquio A disease. Previously reported cases from European countries carry the W273L variant on at least one GLB1 allele and exhibit a pure skeletal phenotype (pure MBD). Only a minority of MBD cases have been described with additional neuronopathic findings (MBD plus). Objectives and Methods With the aim to further describe patterns of MBD‐related dysostosis multiplex, we analyzed clinical, biochemical, and genetic features in 17 cases with GLB1‐related dysostosis multiplex living and diagnosed in Brazil. Results About 14 of the 17 individuals had three or more skeletal findings characteristic of Morquio syndrome. Two had no additional neuronopathic features (pure MBD) and 12 exhibited additional neuronopathic features (MBD plus). Three of the 17 cases had mild dysostosis without distinct features of MBD. Seven of the 12 MBD plus patients had signs of spinal cord compression (SCC), as a result of progressive spinal vertebral dysostosis. There was an age‐dependent increase in the number of skeletal findings and in the severity of growth impairment. GLB1 mutation analysis was completed in 10 of the 14 MBD patients. T500A occurred in compound heterozygosity in 8 of the 19 alleles. Conclusion Our study extends the phenotypic spectrum of GLB1‐related conditions by describing a cohort of patients with MBD and GM1‐gangliosidosis (MBD plus). Targeting the progressive nature of the skeletal manifestations in the development of new therapies for GLB1‐related conditions is warranted.

We assessed the effect of 24-month anti-tumor necrosis factor alpha (TNF-α) treatment on the remodeling of the cartilage extracellular matrix (ECM) in patients with juvenile idiopathic arthritis (JIA). Methods: Quantitative evaluation of keratan sulfate (KS), hyaluronic acid (HA), hyaluronan and proteoglycan link protein 1 (HAPLN1), as potential biomarkers of joint dysfunction, and the levels of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 4 and 5, total oxidative status (TOS) and transforming growth factor (TGF-β1) was performed (using immunoenzymatic methods) in blood obtained from patients before and after 24 months of etanercept (ETA) treatment. Results: When compared to the controls, KS, HA and HAPLN1 levels were significantly higher in patients with an aggressive course of JIA qualified for ETA treatment. An anti-cytokine therapy leading to clinical improvement promotes the normalization only of the HA level. Proteolytic and pro-oxidative factors, present in high concentrations in patients before the treatment, correlated with HAPLN1, but not with KS and HA levels. In these patients, negative correlations were found between the levels of TGF-β1 and KS, HA and HAPLN1. Conclusion: The anti-TNF-α therapy used in patients with JIA has a beneficial effect on ECM cartilage metabolism, but it does not completely regenerate it. The changes in the plasma HA level during the anti-cytokine therapy suggest its potential diagnostic utility in monitoring of disease activity and may be used to assess the efficacy of ETA treatment. [ABSTRACT FROM AUTHOR]

Efficacy and safety of elosulfase alfa enzyme replacement therapy (ERT) were assessed in an open-label, phase 2, multi-national study in Morquio A patients aged ≥5 years unable to walk ≥30 meters in the 6-min walk test. Patients received elosulfase alfa 2.0 mg/kg/week intravenously for 48 weeks. Efficacy measures were functional dexterity, pinch/grip strength, mobility in a modified timed 25-foot walk, pain, quality of life, respiratory function, and urine keratan sulfate (KS). Safety/tolerability was also assessed. Fifteen patients received elosulfase alfa, three patients discontinued ERT due to adverse events (two were grade 3 drug-related adverse events, the other was not drug-related), and two patients missed >20% of planned infusions; 10 completed treatment through 48 weeks and received ≥80% of planned infusions (Modified Per Protocol [MPP] population). The study population had more advanced disease than that enrolled in other trials. From baseline to week 48, MPP data showed biochemical efficacy (urine KS decreased 52.4%). The remaining efficacy results were highly variable due to challenges in test execution because of severe skeletal and joint abnormalities, small sample sizes, and clinical heterogeneity among patients. Eight patients showed improvements in one or more outcome measures; several patients indicated improvements not captured by the study assessments (e.g., increased energy, functional ability). The nature of adverse events was similar to other elosulfase alfa studies. This study illustrates the considerable challenges in objectively measuring impact of ERT in very disabled Morquio A patients and highlights the need to examine results on an individual basis. © 2016 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc.

BackgroundPrevious studies have shown that elosulfase alfa has a favorable efficacy/safety profile in Morquio A patients aged ≥5 y. This study evaluated safety and impact on urine keratan sulfate (uKS) levels and growth velocity in younger patients.MethodsFifteen Morquio A patients aged

The primary treatment outcomes of a phase 2, randomized, double-blind, pilot study evaluating safety, physiological, and pharmacological effects of elosulfase alfa in patients with Morquio A syndrome are herewith presented. Patients aged ≥7 years and able to walk ≥200 m in the 6-min walk test (6MWT) were randomized to elosulfase alfa 2.0 or 4.0 mg/kg/week for 27 weeks. The primary objective was to evaluate the safety of both doses. Secondary objectives were to evaluate effects on endurance (6MWT and 3-min stair climb test [3MSCT]), exercise capacity (cardio-pulmonary exercise test [CPET]), respiratory function, muscle strength, cardiac function, pain, and urine keratan sulfate (uKS) levels, and to determine pharmacokinetic parameters. Twenty-five patients were enrolled (15 randomized to 2.0 mg/kg/week and 10 to 4.0 mg/kg/week). No new or unexpected safety signals were observed. After 24 weeks, there were no improvements versus baseline in the 6MWT, yet numerical improvements were seen in the 3MSCT with 4.0 mg/kg/week. uKS and pharmacokinetic data suggested no linear relationship over the 2.0-4.0 mg/kg dose range. Overall, an abnormal exercise capacity (evaluated in 10 and 5 patients in the 2.0 and 4.0 mg/kg/week groups, respectively), impaired muscle strength, and considerable pain were observed at baseline, and there were trends towards improvements in all domains after treatment. In conclusion, preliminary data of this small study in a Morquio A population with relatively good endurance confirmed the acceptable safety profile of elosulfase alfa and showed a trend of increased exercise capacity and muscle strength and decreased pain.

Recombinant adeno-associated virus (rAAV) vectors are one of the leading tools for the delivery of therapeutic genes in human gene therapy applications. For a successful transfer of their payload, the AAV vectors have to circumvent potential preexisting neutralizing host antibodies and bind to the receptors of the target cells. Both of these aspects have not been structurally analyzed for AAVrh.10. Here, cryo-electron microscopy and three-dimensional image reconstruction were used to map the binding site of sulfated N-acetyllactosamine (LacNAc; previously shown to bind AAVrh.10) and a series of four monoclonal antibodies (MAbs). LacNAc was found to bind to a pocket located on the side of the 3-fold capsid protrusion that is mostly conserved to AAV9 and equivalent to its galactose-binding site. As a result, AAVrh.10 was also shown to be able to bind to cell surface glycans with terminal galactose. For the antigenic characterization, it was observed that several anti-AAV8 MAbs cross-react with AAVrh.10. The binding sites of these antibodies were mapped to the 3-fold capsid protrusions. Based on these observations, the AAVrh.10 capsid surface was engineered to create variant capsids that escape these antibodies while maintaining infectivity. IMPORTANCE Gene therapy vectors based on adeno-associated virus rhesus isolate 10 (AAVrh.10) have been used in several clinical trials to treat monogenetic diseases. However, compared to other AAV serotypes little is known about receptor binding and antigenicity of the AAVrh.10 capsid. Particularly, preexisting neutralizing antibodies against capsids are an important challenge that can hamper treatment efficiency. This study addresses both topics and identifies critical regions of the AAVrh.10 capsid for receptor and antibody binding. The insights gained were utilized to generate AAVrh.10 variants capable of evading known neutralizing antibodies. The findings of this study could further aid the utilization of AAVrh.10 vectors in clinical trials and help the approval of the subsequent biologics. [ABSTRACT FROM AUTHOR]

Galectins are β-galactoside-binding lectins consisting of 15 members in mammals. Galectin-1,-3,-4,-8, and -9 are predominantly expressed in the central nervous system (CNS) and regulate various physiological and pathological events. This review summarizes the current knowledge of the cellular expression and role of galectins in the CNS, and discusses their functions in neurite outgrowth, myelination, and neural stem/progenitor cell niches, as well as in ischemic/hypoxic/traumatic injuries and neurodegenerative diseases such as multiple sclerosis. Galectins are expressed in both neurons and glial cells. Galectin-1 is mainly expressed in motoneurons, whereas galectin-3-positive neurons are broadly distributed throughout the brain, especially in the hypothalamus, indicating its function in the regulation of homeostasis, stress response, and the endocrine/autonomic system. Astrocytes predominantly contain galectin-1, and galectin-3 and−9 are upregulated along with its activation. Activated, but not resting, microglia contain galectin-3, supporting its phagocytic activity. Galectin-1,−3, and -4 are characteristically expressed during oligodendrocyte differentiation. Galectin-3 from microglia promotes oligodendrocyte differentiation and myelination, while galectin-1 and axonal galectin-4 suppress its differentiation and myelination. Galectin-1- and- 3-positive cells are involved in neural stem cell niche formation in the subventricular zone and hippocampal dentate gyrus, and the migration of newly generated neurons and glial cells to the olfactory bulb or damaged lesions. In neurodegenerative diseases, galectin-1,-8, and -9 have neuroprotective and anti-inflammatory activities. Galectin-3 facilitates pro-inflammatory action; however, it also plays an important role during the recovery period. Several ligand glycoconjugates have been identified so far such as laminin, integrins, neural cell adhesion molecule L1, sulfatide, neuropilin-1/plexinA4 receptor complex, triggering receptor on myeloid cells 2, and T cell immunoglobulin and mucin domain. N -glycan branching on lymphocytes and oligodendroglial progenitors mediated by β1,6- N -acetylglucosaminyltransferase V (Mgat5/GnTV) influences galectin-binding, modulating inflammatory responses and remyelination in neurodegenerative diseases. De-sulfated galactosaminoglycans such as keratan sulfate are potential ligands for galectins, especially galectin-3, regulating neural regeneration. Galectins have multitudinous functions depending on cell type and context as well as post-translational modifications, including oxidization, phosphorylation, S-nitrosylation, and cleavage, but there should be certain rules in the expression patterns of galectins and their ligand glycoconjugates, possibly related to glucose metabolism in cells. [ABSTRACT FROM AUTHOR]

Mucopolysaccharidosis type IVA (MPS IVA) is due to the deficiency of GALNS (N-acetylgalactosamine 6-sulfate sulfatase) and is characterized by systemic skeletal dysplasia. We have evaluated adeno-associated virus 8 (AAV8) vectors expressing different forms of human GALNS under a liver-specific promoter. The vectors were delivered intravenously into 4-week-old MPS IVA knockout (KO) and immune tolerant (MTOL) mice at a dose of 5 × 1013 genome copies (GC)/kg. These mice were monitored for 12 weeks post-injection. GALNS enzyme activity was elevated significantly in plasma of all treated mice at 2 weeks post-injection. The activity observed was 4- to 19-fold higher than that in wild-type mice and was maintained throughout the monitoring period. Treatment with AAV vectors resulted in a reduction of keratan sulfate (KS) levels in plasma to normal levels 2 weeks post-injection, which were maintained until necropsy. Both vectors reduced the storage in articular cartilage, ligaments, and meniscus surrounding articular cartilage and growth plate region as well as heart muscle and valves. Our results suggest that the continuous presence of high levels of circulating enzyme increases the penetration into bone and heart and reduces the KS level, thereby improving storage in these regions. The current data support a strategy for developing a novel treatment to address the bone and heart disease in MPS IVA using AAV gene therapy.

Morquio syndrome (MS) is an autosomal recessive defect caused by the deficiency of N-acetylgalactosamine-6-sulfatase. Odontoid hypoplasia, periodontoid soft tissue deposition, and cervical stenosis lead to myelopathy and quadriparesis in these patients. Craniovertebral junction instability in MS possesses a surgical challenge as bones are yet to completely ossify. The atlantoaxial dislocation (AAD) is reducible, and the need of transoral decompression for the soft tissue deposition ventral to odontoid is debatable. We present a series of four cases (mean age 4.3 ± 0.4 years) operated through posterior-only approach (n = 2, C1-lateral mass to C2 pars-interarticularis [Goel's technique]; n = 1 sublaminar wiring followed by C1-lateral mass to C2 pars-interarticularis; and n = 1 suboccipital plate with pars-interarticularis of C2 screw and pedicle of C3 and rod fixation). All patients had acceptable outcome and doing well at the last follow-up (12–96-follow-up). None of our patient needed transoral decompression. Patients with MS frequently manifest with spastic quadriparesis at an early age due to reducible AAD. Early surgical fixation with posterior C1–C2 screw and rod technique is recommended for the favorable surgical outcome and long-term stability of the cervical spine.

Galectins are β-galactoside-binding lectins consisting of 15 members in mammals. Galectin-1,-3,-4,-8, and -9 are predominantly expressed in the central nervous system (CNS) and regulate various physiological and pathological events. This review summarizes the current knowledge of the cellular expression and role of galectins in the CNS, and discusses their functions in neurite outgrowth, myelination, and neural stem/progenitor cell niches, as well as in ischemic/hypoxic/traumatic injuries and neurodegenerative diseases such as multiple sclerosis. Galectins are expressed in both neurons and glial cells. Galectin-1 is mainly expressed in motoneurons, whereas galectin-3-positive neurons are broadly distributed throughout the brain, especially in the hypothalamus, indicating its function in the regulation of homeostasis, stress response, and the endocrine/autonomic system. Astrocytes predominantly contain galectin-1, and galectin-3 and−9 are upregulated along with its activation. Activated, but not resting, microglia contain galectin-3, supporting its phagocytic activity. Galectin-1,−3, and -4 are characteristically expressed during oligodendrocyte differentiation. Galectin-3 from microglia promotes oligodendrocyte differentiation and myelination, while galectin-1 and axonal galectin-4 suppress its differentiation and myelination. Galectin-1- and- 3-positive cells are involved in neural stem cell niche formation in the subventricular zone and hippocampal dentate gyrus, and the migration of newly generated neurons and glial cells to the olfactory bulb or damaged lesions. In neurodegenerative diseases, galectin-1,-8, and -9 have neuroprotective and anti-inflammatory activities. Galectin-3 facilitates pro-inflammatory action; however, it also plays an important role during the recovery period. Several ligand glycoconjugates have been identified so far such as laminin, integrins, neural cell adhesion molecule L1, sulfatide, neuropilin-1/plexinA4 receptor complex, triggering receptor on myeloid cells 2, and T cell immunoglobulin and mucin domain. N-glycan branching on lymphocytes and oligodendroglial progenitors mediated by β1,6-N-acetylglucosaminyltransferase V (Mgat5/GnTV) influences galectin-binding, modulating inflammatory responses and remyelination in neurodegenerative diseases. De-sulfated galactosaminoglycans such as keratan sulfate are potential ligands for galectins, especially galectin-3, regulating neural regeneration. Galectins have multitudinous functions depending on cell type and context as well as post-translational modifications, including oxidization, phosphorylation, S-nitrosylation, and cleavage, but there should be certain rules in the expression patterns of galectins and their ligand glycoconjugates, possibly related to glucose metabolism in cells.

To date, a number of studies have reported the heterogeneity of activated microglia. However, there is increasing evidence suggests that ramified, so‐called resting, microglia may also be heterogeneous, and they may play diverse roles in normal brain homeostasis. Here, we found that both 5D4 keratan sulfate epitope‐positive (5D4+) and 5D4‐negative (5D4‒) microglia coexisted in the hippocampus of normal rats, while all microglia were negative for the 5D4 epitope in the hippocampus of normal mice. We thus aimed to determine the potential heterogeneity of microglia related to the 5D4 epitope in the normal rat hippocampus. The optical disector analysis showed that the densities of 5D4+ microglia were higher in the stratum oriens of the CA3 region than in other layers and regions. Although both 5D4+ and 5D4‒ microglia exhibited a ramified morphology, the three‐dimensional reconstruction analysis showed that the node numbers, end numbers, and complexity of processes were higher in 5D4+ than in 5D4‒ microglia. The linear discriminant analysis showed that 5D4+ and 5D4‒ microglia can be classified into distinct morphometric subtypes. The ratios of contact between synaptic boutons and microglial processes were higher in 5D4+ than in 5D4‒ microglia. The gene expressions of pro‐inflammatory cytokine interleukin‐1β and purinergic receptor P2Y12 (P2Y12R) were higher in 5D4+ than in 5D4‒ microglia. Together, these results indicate that at least two different subtypes of ramified microglia coexist in the normal rat hippocampus and also suggest that 5D4+ microglia may represent a unique subtype associated with synapses. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is invasive or cytotoxic to host cells, depending on the type III secretion system (T3SS) effectors encoded. While the T3SS is known to be involved in disease in vivo, how it participates remains to be clarified. Here, mouse models of superficial epithelial injury (tissue paper blotting with EGTA treatment) and immunocompromise (MyD88 deficiency) were used to study the contribution of the T3SS transcriptional activator ExsA to epithelial traversal. Corneas of excised eyeballs were inoculated with green fluorescent protein (GFP)-expressing PAO1 or isogenic exsA mutants for 6 h ex vivo before bacterial traversal and epithelial thickness were quantified by using imaging. In the blotting-EGTA model, exsA mutants were defective in capacity for traversal. Accordingly, an ∼16-fold variability in exsA expression among PAO1 isolates from three sources correlated with epithelial loss. In contrast, MyD88-/- epithelia remained susceptible to P. aeruginosa traversal despite exsA mutation. Epithelial lysates from MyD88-/- mice had reduced antimicrobial activity compared to those from wild-type mice with and without prior antigen challenge, particularly 30- to 100-kDa fractions, for which mass spectrometry revealed multiple differences, including (i) lower baseline levels of histones, tubulin, and lumican and (ii) reduced glutathione S-transferase, annexin, and dermatopontin, after antigen challenge. Thus, the importance of ExsA in epithelial traversal by invasive P. aeruginosa depends on the compromise enabling susceptibility, suggesting that strategies for preventing infection will need to extend beyond targeting the T3SS. The data also highlight the importance of mimicking conditions allowing susceptibility in animal models and the need to monitor variability among bacterial isolates from different sources, even for the same strain.

ObjectiveTo assess the efficacy and safety of enzyme replacement therapy (ERT) with BMN 110 (elosulfase alfa) in patients with Morquio A syndrome (mucopolysaccharidosis IVA).MethodsPatients with Morquio A aged ≥5 years (N = 176) were randomised (1:1:1) to receive elosulfase alfa 2.0 mg/kg/every other week (qow), elosulfase alfa 2.0 mg/kg/week (weekly) or placebo for 24 weeks in this phase 3, double-blind, randomised study. The primary efficacy measure was 6-min walk test (6MWT) distance. Secondary efficacy measures were 3-min stair climb test (3MSCT) followed by change in urine keratan sulfate (KS). Various exploratory measures included respiratory function tests. Patient safety was also evaluated.ResultsAt week 24, the estimated mean effect on the 6MWT versus placebo was 22.5 m (95 % CI 4.0, 40.9; P = 0.017) for weekly and 0.5 m (95 % CI -17.8, 18.9; P = 0.954) for qow. The estimated mean effect on 3MSCT was 1.1 stairs/min (95 % CI -2.1, 4.4; P = 0.494) for weekly and -0.5 stairs/min (95 % CI -3.7, 2.8; P = 0.778) for qow. Normalised urine KS was reduced at 24 weeks in both regimens. In the weekly dose group, 22.4 % of patients had adverse events leading to an infusion interruption/discontinuation requiring medical intervention (only 1.3 % of all infusions in this group) over 6 months. No adverse events led to permanent treatment discontinuation.ConclusionsElosulfase alfa improved endurance as measured by the 6MWT in the weekly but not qow dose group, did not improve endurance on the 3MSCT, reduced urine KS, and had an acceptable safety profile.

Glycosaminoglycans (GAGs) are linear anionic polysaccharides, and most of them show a specific sulfation pattern. GAGs have been studied for decades, and still, new biological functions are discovered. Hyaluronic acid and heparin are sold for medical or cosmetic applications. With increased market and applications, the production of GAGs stays in the focus of research groups and the industry. Common industrial GAG production relies on the extraction of animal tissue. Contamination, high dispersity, and uncontrolled sulfation pattern are still obstacles to this process. Tailored production strategies for the chemoenzymatic synthesis have been developed to address these obstacles. In recent years, enzyme cascades, including uridine-5′-diphosphate sugar syntheses, were established to obtain defined polymer size and dispersity, as well as defined sulfation patterns. Nevertheless, the complex synthesis of GAGs is still a challenging research field. [Display omitted] • The recent development of the enzymatic synthesis of glycosaminoglycans is presented. • The syntheses of activated precursors to the processing of defined glycosaminoglycans are described. • We focus on tailoring enzyme cascades and the utilization of renewable resources. • An overview of applied enzymes regarding their application and origin is given. [ABSTRACT FROM AUTHOR]

Understanding the basic elements of the airway mucosal surfaces and how they form a functional barrier is essential in understanding disease initiation, progression, pathogenesis and ultimately treating chronic lung diseases. Using primary airway epithelial cell cultures, atomic force microscopy (AFM), multiangle light scattering and quartz crystal micro balance with dissipation monitoring techniques, here we report that the membrane bound mucins (MBMs) found in the periciliary layer (PCL) of the airway surface are densely decorated with keratan sulfate (KS). AFM and immunoblotting show that the KS sidechains can be removed enzymatically with keratanase II (KII) treatment, and the antibody accessibility for B2729 (MUC1), MUCH4 (MUC4) and OC125 (MUC16) was substantially enhanced. Light scattering analysis confirmed that KII treatment removed ~40% of the mass from the mucin fractions. Surface binding experiments indicated that MBMs were able to pack into a tighter conformation following KS removal, suggesting that negatively charged KS sidechains play a role in mucin–mucin repulsion and contribute to "space filling" in the PCL. We also observed that soluble filtrate from the common airway pathogen Pseudomonas aeruginosa is capable of stripping KS from MBMs. Altogether, our findings indicate that KS glycosylation of MBMs may play an important role in the integrity of the airway mucosal barrier and its compromise in disease. [ABSTRACT FROM AUTHOR]

The immunoinhibitory receptor Siglec-8 on the surface of human eosinophils and mast cells binds to sialic acid–containing ligands in the local milieu, resulting in eosinophil apoptosis, inhibition of mast cell degranulation, and suppression of inflammation. Siglec-8 ligands were found on postmortem human trachea and bronchi and on upper airways in 2 compartments, cartilage and submucosal glands, but they were surprisingly absent from the epithelium. We hypothesized that Siglec-8 ligands in submucosal glands and ducts are normally transported to the airway mucus layer, which is lost during tissue preparation. Our aim was to identify the major Siglec-8 sialoglycan ligand on the mucus layer of human airways. Human upper airway mucus layer proteins were recovered during presurgical nasal lavage of patients at a sinus clinic. Proteins were resolved by gel electrophoresis and blotted, and Siglec-8 ligands detected. Ligands were purified by size exclusion and affinity chromatography, identified by proteomic mass spectrometry, and validated by electrophoretic and histochemical colocalization. The affinity of Siglec-8 binding to purified human airway ligand was determined by inhibition of glycan binding. A Siglec-8-ligand with a molecular weight of approximately 1000 kDa was found in all patient nasal lavage samples. Purification and identification revealed deleted in malignant brain tumors 1 (DMBT1) (also known by the aliases GP340 and SALSA), a large glycoprotein with multiple O-glycosylation repeats. Immunoblotting, immunohistochemistry, and enzyme treatments confirmed that Siglec-8 ligand on the human airway mucus layer is an isoform of DMBT1 carrying O-linked sialylated keratan sulfate chains (DMBT1S8). Quantitative inhibition revealed that DMBT1S8 has picomolar affinity for Siglec-8. A distinct DMBT1 isoform, DMBT1S8, is the major high-avidity ligand for Siglec-8 on human airways. [Display omitted] [ABSTRACT FROM AUTHOR]

Mucin-like glycoproteins have established roles in epithelial boundary protection and lubricative roles in some tissues. This mini-review illustrates alternative functional roles which rely on keratan sulphate and sialic acid modifications to mucin glycopolymers which convey charge properties suggestive of novel electroconductive properties not previously ascribed to these polymers. Many tumour cells express mucin-like glycopolymers modified with highly sulphated keratan sulphate and sialic which can be detected using diagnostic biosensors. The mucin-like keratan sulphate glycopolymer present in the ampullae of lorenzini is a remarkable sensory polymer which elasmobranch fish (sharks, rays, skate) use to detect weak electrical fields emitted through muscular activity of prey fish. Information on the proton gradients is conveyed to neuromast cells located at the base of the ampullae and mechanotransduced to neural networks. This ampullae keratan sulphate sensory gel is the most sensitive proton gradient detection polymer known in nature. This process is known as electrolocation, and allows the visualization of prey fish under conditions of low visibility. The bony fish have similar electroreceptors located along their lateral lines which consist of neuromast cells containing sensory hairs located within a cupula which contains a sensory gel polymer which detects distortions in fluid flow in channels within the lateral lines and signals are sent back to neural networks providing information on the environment around these fish. One species of dolphin, the Guiana dolphin, has electrosensory pits in its bill with similar roles to the ampullae but which have evolved from its vibrissal system. Only two terrestrial animals can undertake electrolocation, these are the Duck-billed platypus and long and short nosed Echidna. In this case the electrosensor is a highly evolved innervated mucous gland. The platypus has 40,000 electroreceptors around its bill through which it electrolocates food species. The platypus has poor eyesight, is a nocturnal feeder and closes its eyes, nostrils and ears when it hunts, so electrolocation is an essential sensory skill. Mammals also have sensory cells containing stereocilia which are important in audition in the organ of corti of the cochlea and in olfaction in the olfactory epithelium. The rods and cones of the retina also have an internal connecting cilium with roles in the transport of phototransduced chemical signals and activation of neurotransmitter release to the optic nerve. Mucin-like glycopolymer gels surround the stereocilia of these sensory hair cells but these are relatively poorly characterized however they deserve detailed characterization since they may have important functional attributes.

We assessed the effect of 24-month anti-tumor necrosis factor alpha (TNF-α) treatment on the remodeling of the cartilage extracellular matrix (ECM) in patients with juvenile idiopathic arthritis (JIA). Methods: Quantitative evaluation of keratan sulfate (KS), hyaluronic acid (HA), hyaluronan and proteoglycan link protein 1 (HAPLN1), as potential biomarkers of joint dysfunction, and the levels of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 4 and 5, total oxidative status (TOS) and transforming growth factor (TGF-β1) was performed (using immunoenzymatic methods) in blood obtained from patients before and after 24 months of etanercept (ETA) treatment. Results: When compared to the controls, KS, HA and HAPLN1 levels were significantly higher in patients with an aggressive course of JIA qualified for ETA treatment. An anti-cytokine therapy leading to clinical improvement promotes the normalization only of the HA level. Proteolytic and pro-oxidative factors, present in high concentrations in patients before the treatment, correlated with HAPLN1, but not with KS and HA levels. In these patients, negative correlations were found between the levels of TGF-β1 and KS, HA and HAPLN1. Conclusion: The anti-TNF-α therapy used in patients with JIA has a beneficial effect on ECM cartilage metabolism, but it does not completely regenerate it. The changes in the plasma HA level during the anti-cytokine therapy suggest its potential diagnostic utility in monitoring of disease activity and may be used to assess the efficacy of ETA treatment.

Mucopolysaccharidosis IVA (MPS IVA) is a rare autosomal recessive lysosomal storage disorder resulting from N-acetylgalactosamine-6-sulfatase (GALNS) deficiency that occurs in approximately 1 in 76 000 to 1 in 640 000 live births. Given that the diagnosis of MPS IVA relies heavily on the results of initial urine glycosaminoglycan (GAG) screening, cases that present with falsely normal urine GAG concentrations can delay the diagnosis and follow-up care for patients. This case study follows a patient diagnosed with MPS IVA at 9 months of age based on relation to a consanguineous 3-year-old sibling with MPS IVA and the use of direct enzyme activity analysis. Details regarding skeletal presentation and identification of genetic variants are presented along with data on follow-up urinary GAG monitoring during treatment with enzyme replacement therapy and treatment for a growth hormone disorder. [ABSTRACT FROM AUTHOR]

Glycosylation represents one of the most abundant posttranslational modification of proteins. Glycosylation products are diverse and are regulated by the cooperative action of various glycosyltransferases, glycosidases, substrates thereof: nucleoside sugars and their transporters, and chaperons. In this article, we focus on a glycosyltransferase, α1,6-fucosyltransferase (Fut8) and its product, the core fucose structure on N-glycans, and summarize the potential protective functions of this structure against emphysema and chronic obstructive pulmonary disease (COPD). Studies of FUT8 and its enzymatic product, core fucose, are becoming an emerging area of interest in various fields of research including inflammation, cancer and therapeutics. This article discusses what we can learn from studies of Fut8 and core fucose by using knockout mice or in vitro studies that were conducted by our group as well as other groups. We also include a discussion of the potential protective functions of the keratan sulfate (KS) disaccharide, namely L4, against emphysema and COPD as a glycomimetic. Glycomimetics using glycan analogs is one of the more promising therapeutics that compensate for the usual therapeutic strategy that involves targeting the genome and the proteome. These typical glycans using KS derivatives as glycomimetics, will likely become a clue to the development of novel and effective therapeutic strategies. [ABSTRACT FROM AUTHOR]

The six mammalian glycosaminoglycans (GAGs), chondroitin sulfate, dermatan sulfate, heparin, heparan sulfate, hyaluronan, and keratan sulfate, are linear polysaccharides. Except for hyaluronan, they are sulfated to various extent, and covalently attached to proteins to form proteoglycans. GAGs interact with growth factors, morphogens, chemokines, extracellular matrix proteins and their bioactive fragments, receptors, lipoproteins, and pathogens. These interactions mediate their functions, from embryonic development to extracellular matrix assembly and regulation of cell signaling in various physiological and pathological contexts such as angiogenesis, cancer, neurodegenerative diseases, and infections. We give an overview of GAG–protein interactions (i.e., specificity and chemical features of GAG- and protein-binding sequences), and review the available GAG–protein interaction networks. We also provide the first comprehensive draft of the GAG interactome composed of 832 biomolecules (827 proteins and five GAGs) and 932 protein–GAG interactions. This network is a scaffold, which in the future should integrate structures of GAG–protein complexes, quantitative data of the abundance of GAGs in tissues to build tissue-specific interactomes, and GAG interactions with metal ions such as calcium, which plays a major role in the assembly of the extracellular matrix and its interactions with cells. This contextualized interactome will be useful to identify druggable GAG–protein interactions for therapeutic purpose: [ABSTRACT FROM AUTHOR]

The addition of sulfate to glycan structures can regulate their ability to serve as ligands for glycan-binding proteins. Although sulfate groups present on the monosaccharides glucosamine, uronate, N-acetylglucosamine and N-acetylgalactosamine are recognized by defined receptors that mediate important functions, the functional significance of galactose-6-O-sulfate (Gal6S) is not known. However, in vitro studies using synthetic glycans and sulfotransferase overexpression implicate Gal6S as a binding determinant for the lymphocyte homing receptor, L-selectin. Only two sulfotransferases have been shown to generate Gal6S, namely keratan sulfate galactose 6-O-sulfotransferase (KSGal6ST) and chondroitin 6-O-sulfotransferase-1 (C6ST-1). In the present study, we use mice deficient in KSGal6ST and C6ST-1 to test whether Gal6S contributes to ligand recognition by L-selectin in vivo. First, we establish that KSGal6ST is selectively expressed in high endothelial venules (HEVs) in lymph nodes and Peyer's patches. We also determine by mass spectrometry that KSGal6ST generates Gal6S on several classes of O-glycans in peripheral lymph nodes. Furthermore, KSGal6ST, but not C6ST-1, is required for the generation of the Gal6S-containing glycan, 6,6'-disulfo-3'sLN (Siaα2→3[6S]Galβ1→4[6S]GlcNAc) or a closely related structure in lymph node HEVs. Nevertheless, L-selectin-dependent short-term homing of lymphocytes is normal in KSGal6ST-deficient mice, indicating that the Gal6S-containing structures we detected do not contribute to L-selectin ligand recognition in this setting. These results refine our understanding of the biological ligands for L-selectin and introduce a mouse model for investigating the functions of Gal6S in other contexts.

Mucopolysaccharidoses (MPS) screening is tedious and still performed by analysis of total glycosaminoglycans (GAG) using 1,9-dimethylmethylene blue (DMB) photometric assay, although false positive and negative tests have been reported. Analysis of differentiated GAGs have been pursued classically by gel electrophoresis or more recently by quantitative LC-MS assays. Secondary elevations of GAGs have been reported in urinary tract infections (UTI). In this manuscript, we describe the diagnostic accuracy of urinary GAG measurements by LC-MS for MPS typing in 68 untreated MPS and mucolipidosis (ML) patients, 183 controls and 153 UTI samples. We report age-dependent reference values and cut-offs for chondroitin sulfate (CS), dermatan sulfate (DS), heparan sulfate (HS) and keratan sulfate (KS) and specific GAG ratios. The use of HS/DS ratio in combination to GAG concentrations normalized to creatinine improves the diagnostic accuracy in MPS type I, II, VI and VII. In total 15 samples classified to the wrong MPS type could be correctly assigned using HS/DS ratio. Increased KS/HS ratio in addition to increased KS improves discrimination of MPS type IV by excluding false positives. Some samples of UTI patients showed elevation of specific GAGs, mainly CS, KS and KS/HS ratio and could be misclassified as MPS type IV. Finally, DMB photometric assay performed in MPS and ML samples reveal four false negative tests (sensitivity of 94%). In conclusion, specific GAG ratios in complement to quantitative GAG values obtained by LC-MS enhance discrimination of MPS types. Exclusion of patients with UTI improve diagnostic accuracy in MPS IV but not in other types., Competing Interests: Déborah Mathis, Jean‐Christophe Prost, Gabriela Mäder, Liya Arackal, Haoyue Zhang, Sandra Kurth, Katrin Freiburghaus, and Jean‐Marc Nuoffer declare that they have no conflict of interest., (© 2024 The Authors. JIMD Reports published by John Wiley & Sons Ltd on behalf of SSIEM.)

β1,4-galactosyltransferase 4 (B4GalT4) is one of seven B4GalTs that belong to CAZy glycosyltransferase family 7 and transfer galactose to growing sugar moieties of proteins, glycolipids, glycosaminoglycans as well as single sugar for lactose synthesis. Herein, we identify two asparagine-linked glycosylation sites in B4GalT4. We found that mutation of one site (Asn220) had greater impact on enzymatic activity while another (Asn335) on Golgi localization and presence of N-glycans at both sites is required for production of stable and enzymatically active protein and its secretion. Additionally, we confirm B4GalT4 involvement in synthesis of keratan sulfate (KS) by generating A375 B4GalT4 knock-out cell lines that show drastic decrease in the amount of KS proteoglycans and no significant structural changes in N- and O-glycans. We show that KS decrease in A375 cells deficient in B4GalT4 activity can be rescued by overproduction of either partially or fully glycosylated B4GalT4 but not with N-glycan-depleted B4GalT4 version. [ABSTRACT FROM AUTHOR]

The ocular surface, which forms the interface between the eye and the external environment, includes the cornea, corneoscleral limbus, the conjunctiva and the accessory glands that produce the tear film. Glycosaminoglycans (GAGs) and proteoglycans (PGs) have been shown to play important roles in the development, hemostasis and pathology of the ocular surface. Herein we review the current literature related to the distribution and function of GAGs and PGs within the ocular surface, with focus on the cornea. The unique organization of ECM components within the cornea is essential for the maintenance of corneal transparency and function. Many studies have described the importance of GAGs within the epithelial and stromal compartment, while very few studies have analyzed the ECM of the endothelial layer. Importantly, GAGs have been shown to be essential for maintaining corneal homeostasis, epithelial cell differentiation and wound healing, and, more recently, a role has been suggested for the ECM in regulating limbal stem cells, corneal innervation, corneal inflammation, corneal angiogenesis and lymphangiogenesis. Reports have also associated genetic defects of the ECM to corneal pathologies. Thus, we also highlight the role of different GAGs and PGs in ocular surface homeostasis, as well as in pathology.

Acute aortic dissection (AAD) is a serious vascular disease. Currently the diagnosis relies on clinical and radiological means whereas serum biomarkers are lacking. The purpose of this study was to identify potential serum biomarkers for AAD using isobaric tags for relative and absolute quantitation (iTRAQ) approach. A total of 120 serum samples were collected from three groups: AAD patients (n = 60), patients with acute myocardial infarction (AMI, n = 30), and healthy volunteers (n = 30), whereas the first 10 samples from each group were used for iTRAQ analysis. Using iTRAQ approach, a total of 174 proteins were identified as significantly different between AAD patients and healthy subjects. Among them, forty-six proteins increased more than twofold, full-scale analysis using serum sample for the entire 120 subjects demonstrated that Lumican level was significantly increased relative to control and AMI samples. Further, Lumican level correlated with time from onset to admission in AAD but not AMI samples. Using iTRAQ approach, our study showed that Lumican may be a potential AAD-related serum marker that may assist the diagnosis of AAD.

Abstract Background In this study, the effect of 15-month anti-tumor necrosis factor alpha (TNF-α) treatment on circulating levels of plasma sulfated glycosaminoglycans (GAGs) and the nonsulfated GAG hyaluronic acid (HA) in female rheumatoid arthritis (RA) patients was assessed. Methods Plasma was obtained from healthy subjects and RA women treated with TNF-α antagonists (etanercept or adalimumab or certolizumab pegol) in combination with methotrexate. GAGs were isolated from plasma samples using ion exchange low-pressure liquid chromatography. Total sulfated GAGs were quantified using a hexuronic acid assay. Plasma levels of keratan sulfate (KS) and HA were measured using immunoassay kits. Results Total sulfated GAGs and HA levels were higher in female RA patients before treatment in comparison to healthy subjects. KS levels did not differ between RA women and controls. Anti-TNF-α treatment resulted in normalization of plasma total GAG and HA levels in RA patients, without any effect on KS levels. Conclusions Our results suggest that anti-TNF-α therapy has a beneficial effect on extracellular matrix remodeling in the course of RA.

Morquio A syndrome (mucopolysaccharidosis IVA, MPS IVA) is a lysosomal storage disease caused by a deficiency of N-acetylgalactosamine-6-sulfate sulfatase, resulting in systemic accumulation of the partially degraded glycosaminoglycans (GAGs), keratan sulfate and chondroitin-6-sulfate. The accumulation of these GAGs leads to distinguishing features as skeletal dysplasia with disproportionate dwarfism, short neck, kyphoscoliosis, pectus carinatum, tracheal obstruction, coxa valga, genu valgum, and joint laxity. In the absence of autopsied cases and systemic analysis of multiple tissues, the pathological mechanism of the characteristic skeletal dysplasia associated with the disease largely remains a question. Here we report an autopsied case of a 23-year-old male with MPS IVA, who developed characteristic skeletal abnormalities by 4 months of age and died of severe tracheal obstruction and hypoventilation originating from respiratory muscle weakness from neurological cord deficit due to cord myelopathy at the age of 23. We analyzed postmortem tissues pathohistologically, including the thyroid, lung, lung bronchus, trachea, heart, aorta, liver, spleen, kidney, testes, humerus, knee cartilage, and knee ligament. Examination of the tissues demonstrated systemic storage materials in multiple tissues, as well as severely ballooned and vacuolated chondrocytes in the trachea, humerus, knee cartilage, and lung bronchus. This autopsied case with MPS IVA addresses the importance of tracheal obstruction for morbidity and mortality of the disease, and the pathological findings contribute to a further understanding of the pathogenesis of MPS IVA and the development of novel therapies.

Glycosaminoglycans are important complex carbohydrates that are used in a number of pharmaceutical products. Because glycosaminoglycans are obtained by isolation from biological materials, their pharmaceutical analysis before therapeutic use is of paramount importance. Due to their versatility, wide applicability, non-destructiveness, and in particular the possibility of obtaining a "fingerprint" clearly proving the given chemical specie, spectrometric methods are one of the essential methods used for these analyzes. This review is focused on significant spectrometric methods used in the pharmaceutical analysis of glycosaminoglycans. The advantages and prospects of individual methods (NMR spectrometry, infrared and Raman spectrometry, UV/Vis spectrometry, spectrofluorimetry, chemiluminescence, and circular dichroism) used and methodological aspects of the analysis are discussed. The possibilities of further development and application of spectral methods in the discussed area are outlined. [ABSTRACT FROM AUTHOR]

Morquio syndrome (MS) is an autosomal recessive defect caused by the deficiency of N-acetylgalactosamine-6-sulfatase. Odontoid hypoplasia, periodontoid soft tissue deposition, and cervical stenosis lead to myelopathy and quadriparesis in these patients. Craniovertebral junction instability in MS possesses a surgical challenge as bones are yet to completely ossify. The atlantoaxial dislocation (AAD) is reducible, and the need of transoral decompression for the soft tissue deposition ventral to odontoid is debatable. We present a series of four cases (mean age 4.3 ± 0.4 years) operated through posterior-only approach (n = 2, C1-lateral mass to C2 pars-interarticularis [Goel's technique]; n = 1 sublaminar wiring followed by C1-lateral mass to C2 pars-interarticularis; and n = 1 suboccipital plate with pars-interarticularis of C2 screw and pedicle of C3 and rod fixation). All patients had acceptable outcome and doing well at the last follow-up (12–96-follow-up). None of our patient needed transoral decompression. Patients with MS frequently manifest with spastic quadriparesis at an early age due to reducible AAD. Early surgical fixation with posterior C1–C2 screw and rod technique is recommended for the favorable surgical outcome and long-term stability of the cervical spine. [ABSTRACT FROM AUTHOR]

Glycosaminoglycans (GAGs) are negatively charged long linear (highly sulfated) polysaccharides consisting of repeating disaccharide units that are expressed on the surfaces of all nucleated cells. The expression of GAGs is required for embryogenesis, regulation of cell growth and proliferation, maintenance of tissue hydration, and interactions of the cells via receptors. Mucopolysaccharidoses (MPS) are caused by deficiency of specific lysosomal enzymes that result in the accumulation of GAGs in multiple tissues leading to organ dysfunction. Therefore, GAGs are important biomarkers for MPS. Without any treatment, patients with severe forms of MPS die within the first two decades of life. Accurate measurement of GAGs is important to understand the diagnosis and pathogenesis of MPS and to monitor therapeutic efficacy before, during, and after treatment of the disease. This review covers various qualitative and quantitative methods for measurement of GAGs, including dye specific, thin layer chromatography (TLC), capillary electrophoresis, high-performance liquid chromatography (HPLC), liquid chromatography-tandem mass spectrometry (LC-MS/MS), gas chromatography, ELISA, and automated high-throughput mass spectrometry. Major conclusion: There are several methods for GAG detection however, specific GAG detection in the various biological systems requires rapid, sensitive, specific, and cost-effective methods such as LC-MS/MS. This review will describe different methods for GAG detection and analysis, including their advantages and limitation. [ABSTRACT FROM AUTHOR]

Induction of keratan sulfate in microglia has been found in several animal models of neurological disorders. However, the significance of keratan sulfate‐expressing microglia is not fully understood. To address this issue, we analyzed the characteristics of microglia labeled by the 5D4 epitope, a marker of high‐sulfated keratan sulfate, in the mouse hippocampus during the latent period after pilocarpine‐induced status epilepticus (SE). Only 5D4‐negative (5D4−) microglia were found in the CA1 region of vehicle‐treated controls and pilocarpine‐treated mice at 1 day after SE onset. A few 5D4+ microglia appeared in the strata oriens and radiatum at 5 days post‐SE, and they were distributed into the stratum pyramidale at 14 days post‐SE. The expressions of genes related to both anti‐ and pro‐inflammatory cytokines were higher in 5D4+ cells than in 5D4− cells at 5 but not 14 days post‐SE. The expressions of genes related to phagocytosis were higher in 5D4+ cells than in 5D4− cells throughout the latent period. The phagocytic activity of microglia, as measured by engulfment of the zymosan bioparticles, was higher in 5D4+ cells than in 5D4− cells. The contact ratios between excitatory synaptic boutons and microglia were also higher in 5D4+ cells than in 5D4− cells at 5 and 14 days post‐SE. The excitatory/inhibitory ratios of synaptic boutons within the microglial domain were lower in 5D4+ cells than in 5D4− cells at 14 days post‐SE. Our findings indicate that 5D4+ microglia may play some role in epileptogenesis via pruning of excitatory synapses during the latent period after SE. [ABSTRACT FROM AUTHOR]

Abstract Background We aimed to determine whether synovial fluid (SF) biomarkers can predict the progression of articular cartilage damage as determined by arthroscopic evaluation during and after anterior cruciate ligament (ACL) reconstruction. Methods Arthroscopic assessment of articular cartilage damage was performed twice in 62 patients, first during ACL reconstruction and then approximately 2 years later during implant removal for ligament fixation. SF levels of the collagenase-generated cleavage neoepitope of type II collagen (C2C) and proteoglycan glycosaminoglycans keratan sulfate (KS), chondroitin-4-sulfate (Δdi-C4S), and chondroitin-6-sulfate (Δdi-C6S) were measured at ACL reconstruction. Associations between baseline biomarker levels and subsequent progression of cartilage damage were determined using receiver operating characteristic analysis and multivariable logistic regression analysis. Results No radiographic changes were observed in any of the patients. Progression of high-grade cartilage damage, observed arthroscopically, was negatively correlated with levels of Δdi-C6S and KS, as well as the ratio of Δdi-C6S to Δdi-C4S (C6S/C4S). Logistic regression analysis revealed significant associations of Δdi-C6S (cut-off: 55.7 nmol/ml, odds ratio (OR) 0.231, 95% confidence interval (CI) 0.061–0.879), KS (cut-off: 10.6 μg/ml, OR 0.114, 95% CI 0.024–0.529), and C6S/C4S ratio (cut-off: 4.6, OR 0.060, 95% CI 0.005–0.737) with the progression of high-grade cartilage damage after adjusting for age, the duration from injury to first surgery, sex, and the number of high-grade lesions (grades III and IV) at baseline. Conclusions The progression of high-grade cartilage damage was significantly associated with baseline levels of proteoglycan glycosaminoglycan biomarkers; namely, Δdi-C6S, KS, and C6S/C4S ratio.