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Young blood plasma is known to confer beneficial effects on various organs in mice and rats. However, it was not known whether plasma from young adult pigs rejuvenates old rat tissues at the epigenetic level; whether it alters the epigenetic clock, which is a highly accurate molecular biomarker of aging. To address this question, we developed and validated six different epigenetic clocks for rat tissues that are based on DNA methylation values derived from n = 613 tissue samples. As indicated by their respective names, the rat pan-tissue clock can be applied to DNA methylation profiles from all rat tissues, while the rat brain, liver, and blood clocks apply to the corresponding tissue types. We also developed two epigenetic clocks that apply to both human and rat tissues by adding n = 1366 human tissue samples to the training data. We employed these six rat clocks to investigate the rejuvenation effects of a porcine plasma fraction treatment in different rat tissues. The treatment more than halved the epigenetic ages of blood, heart, and liver tissue. A less pronounced, but statistically significant, rejuvenation effect could be observed in the hypothalamus. The treatment was accompanied by progressive improvement in the function of these organs as ascertained through numerous biochemical/physiological biomarkers, behavioral responses encompassing cognitive functions. An immunoglobulin G (IgG) N-glycosylation pattern shift from pro- to anti-inflammatory also indicated reversal of glycan aging. Overall, this study demonstrates that a young porcine plasma-derived treatment markedly reverses aging in rats according to epigenetic clocks, IgG glycans, and other biomarkers of aging.

Enzyme replacement therapy (ERT) is the only approved disease-modifying treatment modality for Pompe disease, a rare, inherited metabolic disorder caused by a deficiency in the acid α -glucosidase (GAA) enzyme that catabolizes lysosomal glycogen. First-generation recombinant human GAA (rhGAA) ERT (alglucosidase alfa) can slow the progressive muscle degeneration characteristic of the disease. Still, most patients experience diminished efficacy over time, possibly because of poor uptake into target tissues. Next-generation ERTs aim to address this problem by increasing bis-phosphorylated high mannose (bis-M6P) N -glycans on rhGAA as these moieties have sufficiently high receptor binding affinity at the resultant low interstitial enzyme concentrations after dosing to drive uptake by the cation-independent mannose 6-phosphate receptor on target cells. However, some approaches introduce bis-M6P onto rhGAA via non-natural linkages that cannot be hydrolyzed by natural human enzymes and thus inhibit the endolysosomal glycan trimming necessary for complete enzyme activation after cell uptake. Furthermore, all rhGAA ERTs face potential inactivation during intravenous delivery (and subsequent non-productive clearance) as GAA is an acid hydrolase that is rapidly denatured in the near-neutral pH of the blood. One new therapy, cipaglucosidase alfa plus miglustat, is hypothesized to address these challenges by combining an enzyme enriched with naturally occurring bis-M6P N -glycans with a small-molecule stabilizer. Here, we investigate this hypothesis by analyzing published and new data related to the mechanism of action of the enzyme and stabilizer molecule. Based on an extensive collection of in vitro , preclinical, and clinical data, we conclude that cipaglucosidase alfa plus miglustat successfully addresses each of these challenges to offer meaningful advantages in terms of pharmacokinetic exposure, target-cell uptake, endolysosomal processing, and clinical benefit. [ABSTRACT FROM AUTHOR]

Artocarpus lakoocha agglutinin (ALA), which specifically targets the Gal/GalNAc components of complex glycans, was isolated from the seeds of Artocarpus lakoocha. This study is the first to explore the role of ALA in identifying aberrant glycans, designated ALA-binding glycans (ALAG), and its implications in cholangiocarcinoma (CCA). ALA-histochemistry was used to evaluate ALAG expression in liver fluke-induced CCA tissues from hamsters (n = 60). Elevated ALAG expression was observed in hyperplastic ducts and significantly increased in CCA tissues, while normal biliary epithelium and hepatocytes showed no expression. Similar results were found in patient CCA tissues (n = 68), where higher ALAG levels correlated with shorter survival rates, indicating the involvement of ALAG in CCA development and progression. Furthermore, ALA treatment inhibited cell viability in CCA cell lines, as demonstrated by MTT and colony formation assays, and Ki-67 expression. ALA treatment also decreased cell migration and invasion, as shown by Transwell assays. Gelatin zymography suggested that these effects might be associated with reduced MMP-9 activity. Overall, these findings may position ALAG as a potential marker for poor prognosis in CCA, while ALA may serve as a novel lectin for both detection and therapeutic applications in CCA. [ABSTRACT FROM AUTHOR]

Cancers utilize a simple glycan, Sialic Acid, to engage in metastatic processes via the Sialic acid (Sia) -Selectin pathway. Selectins recognize and bind to sialylated substrates, resulting in adhesion, migration, and extravasation, however, how deviations from the canonical form of Sia regulate binding to Selectin receptors (E, L, and P) on hemopoietic cells resulting in these metastatic processes, remained a gap in knowledge. De-O-acetylated Sias has been recently shown to be an integral substrate to the binding of sialic acid binding proteins. The two proteins responsible for regulating the acetyl functional group on Sia's C6 tail, are Sialic acid acetylesterase (SIAE) and Sialic acid O acetyltransferase (CASD1). To elucidate the contribution of functional group alterations on Sia, 9-O and 7,9-O-acetylation of Sia was modulated via the use of CRISRP-Cas9 gene editing and with Sialyl Glycan Recognition Probes, to produce either O-acetylated-Sia or de-O-acetylated- Sia, respectively. In vitro experiments revealed that increased cell surface expression of de-O-acetylated- Sia resulted in an increase in Selectin binding, enhanced cell proliferation, and increased migration capabilities both in lung and colon cancer. These results delineate for the first time the mechanistic contribution of de-O-acetylated-Sia to Selectin binding, reinforcing the importance of elucidating functional group alterations on Sia and their contribution. Without accurate identification of which functionalized form of Sia is being utilized to bind to sialic acid binding proteins, we cannot accurately produce glycan therapeutics with the correct specificity and reactivity, thus this work contributes an integral component in the development of promising therapeutic avenues, for example in the realm of enzyme antibody drug conjugates. [ABSTRACT FROM AUTHOR]

Background. Naturally occurring human antibodies against glycans recognize and quickly eliminate infectious bacteria, viruses and aberrantly glycosylated neoplastic malignant cells, and they often initiate processes that involve the complement system. Methods. Using a printed glycan array (PGA) containing 605 glycoligands (oligo- and polysaccharides, glycopeptides), we examined which of the glycan-binding antibodies are able to activate the complement system. Using this PGA, the specificities of antibodies of the IgM and IgG classes were determined in the blood serum of healthy donors (suggested as mostly natural), and, then, using the same array, it was determined which types of the bound immunoglobulins were also showing C3 deposition. Results. It was found that about 30% of anti-glycan antibodies in human serum detected by the PGA did not activate the complement. They were mostly IgGs and directed to bacterial O-antigens; no apparent common structural motif within their target polysaccharides was found. Antibodies to blood group systems ABO and Forssman, xeno-antigens, a number of polysaccharides from various strains of S. enterica, E. coli and P. alcalifaciens, as well as small fragments of bacterial polysaccharides were recognized by complement-activating antibodies as expected. A complement-activating antibody was affinity-isolated on glycan-Sepharose from human serum, and, in the presence of the complement, it lysed red blood cells coated with the same glycan (kodecytes, where glycans expressed on biological membranes), while an isolated complement non-activating antibody did not, which confirms the validity of the solid-phase PGA results. Conclusions. Thus, ~30% of human anti-glycan antibodies lack the ability to activate the complement system. The function of the widely represented immunoglobulins that do not cause C3 deposition remains unclear. [ABSTRACT FROM AUTHOR]

The tick-borne encephalitis virus is a pathogen endemic to northern Europe and Asia, transmitted through bites from infected ticks. It is a member of the Flaviviridae family and possesses a positive-sense, single-stranded RNA genome encoding a polypeptide that is processed into seven non-structural and three structural proteins, including the envelope (E) protein. The glycosylation of the E protein, involving a single N-linked glycan at position N154, plays a critical role in viral infectivity and pathogenesis. Here, we dissected the entire glycosylation profile of the E protein using liquid chromatography-tandem mass spectrometry and identified three novel O-linked glycans, which were found at relatively low frequency. One of the O-linked glycans was positioned close to the highly conserved N-linked glycan site, and structural analysis suggested that it may be relevant for the function of the E 150-loop. The N154 site was found to be glycosylated with a high frequency, containing oligomannose or complex-type structures, some of which were fucosylated. An unusually high portion of oligomannose N-linked glycan structures exhibited compositions that are normally observed on proteins when they are translocated from the endoplasmic reticulum to the trans-Golgi network, suggesting disruption of the glycan processing pathway in the infected cells from which the E protein was obtained. [ABSTRACT FROM AUTHOR]

Research on virus/receptor interactions has uncovered various mechanisms of antibody‐mediated neutralization against severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). However, understanding of neutralization by antibodies targeting the silent face, which recognize epitopes on glycan shields, remains limited, and their potential protective efficacy in vivo is not well understood. This study describes a silent face neutralizing antibody, 3711, which targets a non‐supersite on the N‐terminal domain (NTD) of the spike protein. Cryo‐EM structure determination of the 3711 Fab in the spike complex reveals a novel neutralizing epitope shielded by glycans on the spike's silent face. Antibody 3711 inhibits the interaction between the receptor‐binding domain (RBD) and human angiotensin‐converting enzyme 2 (hACE2) through steric hindrance and exhibits superior in vivo protective effects compared to other reported NTD‐targeted monoclonal antibodies (mAbs). Competition assays and antibody repertoire analysis indicate the rarity of antibodies targeting the 3711‐related epitope in SARS‐CoV‐2 convalescents, suggesting the infrequency of NTD silent face‐targeted neutralizing antibodies during SARS‐CoV‐2 infection. As the first NTD silent face‐targeted neutralizing antibody against SARS‐CoV‐2, the identification of mAb 3711, with its novel neutralizing mechanism, enhances our understanding of neutralizing epitopes on glycan shields and elucidates epitope‐guided viral mutations that evade specific antibodies. [ABSTRACT FROM AUTHOR]

Ageing is a complex biological process with variations among individuals, leading to the development of ageing clocks to estimate biological age. Glycans, particularly in immunoglobulin G (IgG), have emerged as potential biomarkers of ageing, with changes in glycosylation patterns correlating with chronological age. For precision analysis, three different plasma pools were analysed over 26 days in tetraplicates, 312 samples in total. In short-term variability analysis, two cohorts were analysed: AstraZeneca MFO cohort of 26 healthy individuals (median age 20) and a cohort of 70 premenopausal Chinese women (median age 22.5) cohort monitored over 3 months. Long-term variability analysis involved two adult men aged 47 and 57, monitored for 5 and 10 years, respectively. Samples were collected every 3 months and 3 weeks, respectively. IgG N-glycan analysis followed a standardized approach by isolating IgG, its subsequent denaturation and deglycosylation followed by glycan cleanup and labelling. Capillary gel electrophoresis with laser-induced fluorescence (CGE-LIF) and ultra-performance liquid chromatography analyses were employed for glycan profiling. Statistical analysis involved normalization, batch correction, and linear mixed models to assess time effects on derived glycan traits. The intermediate precision results consistently exhibited very low coefficient of variation values across all three test samples. This consistent pattern underscores the high level of precision inherent in the CGE method for analysing the glycan clock of ageing. The AstraZeneca MFO cohort did not show any statistically significant trends, whereas the menstrual cycle cohort exhibited statistically significant trends in digalactosylated (G2), agalactosylated (G0) and fucosylation (F). These trends were attributed to the effects of the menstrual cycle. Long-term stability analysis identified enduring age-related trends in both subjects, showing a positive time effect in G0 and bisected N-acetylglucosamine, as well as a negative time effect in G2 and sialylation, aligning with earlier findings. Time effects measured for monogalactosylation, and F remained substantially lower than ones observed for other traits. The study found that IgG N-glycome analysis using CGE-LIF exhibited remarkably high intermediate precision. Moreover, the study highlights the short- and long-term stability of IgG glycome composition, coupled with a notable capacity to adapt and respond to physiological changes and environmental influences such as hormonal changes, disease, and interventions. The discoveries from this study propel personalized medicine forward by deepening our understanding of how IgG glycome relates to age-related health concerns. This study underscores the reliability of glycans as a biomarker for tracking age-related changes and individual health paths. [ABSTRACT FROM AUTHOR]

Engineering of extracellular vesicles (EVs) towards more efficient targeting and uptake to specific cells has large potentials for their application as therapeutics. Carbohydrates play key roles in various biological interactions and are essential for EV biology. The extent to which glycan modification of EVs can be achieved through genetic glycoengineering of their parental cells has not been explored yet. Here we introduce targeted glycan modification of EVs through cell-based glycoengineering via modification of various enzymes in the glycosylation machinery. In a "simple cell" strategy, we modified major glycosylation pathways by knocking-out (KO) essential genes for N-glycosylation (MGAT1), O-GalNAc glycosylation (C1GALT1C1), glycosphingolipids (B4GALT5/6), glycosaminoglycans (B4GALT7) and sialylation (GNE) involved in the elongation or biosynthesis of the glycans in HEK293F cells. The gene editing led to corresponding glycan changes on the cells as demonstrated by differential lectin staining. Small EVs (sEVs) isolated from the cells showed overall corresponding glycan changes, but also some unexpected differences to their parental cell including enrichment preference for certain glycan structures and absence of other glycan types. The genetic glycoengineering did not significantly impact sEVs production, size distribution, or syntenin-1 biomarker expression, while a clonal influence on sEVs production yields was observed. Our findings demonstrate the successful implementation of sEVs glycoengineering via genetic modification of the parental cell and a stable source for generation of glycoengineered sEVs. The utilization of glycoengineered sEVs offers a promising opportunity to study the role of glycosylation in EV biology, as well as to facilitate the optimization of sEVs for therapeutic purposes. • Glycan modification of sEVs can be accomplished by genetic glycoengineering the cells from which they originate. • Glycan alterations on sEVs are not always in line with those found on their parental cells. • Glycoengineering of cells does not significantly affect the production, size, or expression of biomarkers on sEVs. • Cell-based glycoengineering enables the stable large-scale production of glycoengineered sEVs. [ABSTRACT FROM AUTHOR]

The clinical diagnosis of major depressive disorder (MDD) still depends on subjective information in terms of various symptoms regarding mood. Detecting the characterization of extracellular vesicles (EVs) in blood may result in finding a diagnostic biomarker that reflects the depressive stage of patients with MDD. Here, we report the results on the glycosylation pattern of enriched plasma EVs from patients with MDD. We compared glycosylation patterns by lectin blotting expressed in EVs isolated from the plasma of both patients with MDD and age-matched healthy control participants (HCs) using size-exclusion chromatography. The levels of Wheat germ agglutinin (WGA), N-acetyl glucosamine (GlcNAc), and N-Acetylneuraminic acid (Neu5Ac, sialic acid) - binding lectin, were significantly decreased in patients with MDD in the depressive state compared to HCs and in remission state. Furthermore, proteome analysis revealed that the von Willebrand factor (vWF) was a significant factor recognized by WGA. WGA-binding vWF antigen differentiated patients with MDD versus HCs and the same patients with MDD in a depressive versus remission state. In this study, the change patterns in the glycoproteins contained in plasma EVs support the usability of testing to identify patients who are at increased risk of depression during antidepressant treatment. [ABSTRACT FROM AUTHOR]

Simple Summary: Cross-reactive carbohydrate determinants (CCDs) are complex sugars found mainly on plant allergens. In people with allergies, antibodies (IgE) against CCDs can develop, causing differences between blood tests and skin tests; these antibodies are believed not to be harmful. CCD-IgE are also found in pets, but their impact is unclear. In this study of 34 dogs with skin allergies, 14 dogs (41.2%) had detectable CCD-IgE antibodies. These antibodies reacted differently to four types of proteins with CCDs. Dogs with CCD-IgE showed more positive reactions to plant extracts in blood tests but not in skin tests. Injecting two CCD proteins into the skin of dogs with CCD-IgE in their blood did not cause immediate reactions. Similarly, these proteins did not activate mast cells, the main allergic cells. This suggests that, like in humans, CCD-IgE antibodies in dogs are not very harmful. Therefore, blocking these antibodies in allergy blood tests is important to help avoid false positives. Cross-reactive carbohydrate determinants (CCDs) are complex N-glycans shared among allergens of plant, insect venom, and nematode origin. In allergic humans, IgE anti-CCD often develop and cause discrepancies between serological and skin tests. Overall, CCD-IgE are believed to be of low pathogenic relevance. IgE-targeting CCDs are also detected in companion animals, but their pathogenic potential and biological relevance are unknown. Herein, we first establish that, in 34 dogs with atopic dermatitis, the presence of serum anti-CCD IgE was detected in 14 pets (41.2%). In dogs, as in humans, IgE-targeting CCDs are heterogeneous, as they differentially recognized four distinct CCD-expressing proteins. The presence of CCD-IgE was associated with a higher and more frequent recognition of plant extracts in serological but not intradermal tests. Two different CCD-expressing proteins did not elicit immediate reactions when injected intradermally in dogs with detectable serum anti-CCD IgE. Similarly, two different CCD-expressing proteins did not induce the activation of mast cells passively transferred with canine anti-CCD IgE. Altogether, these results suggest that in dogs, as in humans, anti-CCD IgE are likely to have little pathogenic potential and blocking them in allergen-specific IgE serological tests is warranted to avoid false-positive results to plant extracts. [ABSTRACT FROM AUTHOR]

The structures of glycans, specifically their terminal positions, play an important role as ligands for receptors in regulating the adhesion ability of platelets. Recent advances in our understanding of free/unbound serotonin (5-HT) in blood plasma at supraphysiological levels implicate it as one of the most profound influencers in remodeling the platelet's surface N-glycans. Proteomic analysis of the membrane vesicles identified enzymes, specifically glycosyltransferases, only on the surface of the platelets isolated from the supraphysiological level of 5-HT-containing blood plasma. However, these enzymes can only be effective on the cell surface under certain biological conditions, such as the level of their substrates, temperature, and pH of the environment. We hypothesize that exosomes released from various cells coordinate the required criteria for the enzymatic reaction on the platelet surface. The elevated plasma 5-HT level also accelerates the release of exosomes from various cells, as reported. This review summarizes the findings from a wide range of literature and proposes mechanisms to coordinate the exosomes and plasma 5-HT in remodeling the structures of N-glycans to make platelets more prone to aggregation. [ABSTRACT FROM AUTHOR]

Protein glycosylation, the most universal post-translational modification, is thought to play a crucial role in regulating multiple essential cellular processes. However, the low abundance of glycoproteins and the heterogeneity of glycans complicate their comprehensive analysis. Here, we develop a rapid and large-scale glycopeptide enrichment strategy via bioorthogonal ligation and trypsin cleavage. The enrichment process is performed in one tube to minimize sample loss and time costs. This method combines convenience and practicality, identifying over 900 O-GlcNAc sites from a 500 μg sample. Surprisingly, it allows simultaneous identification of N-glycosites, O-GlcNAc sites, O-GalNAc sites and N-glycans via a two-step enzymatic release strategy. Combined with quantitative analysis, it reveals the distinct O-GlcNAcylation patterns in different compartments during oxidative stress. In summary, our study offers a convenient and robust tool for glycoproteome and glycome profiling, facilitating in-depth analysis to elucidate the biological functions of glycosylation. [ABSTRACT FROM AUTHOR]

A human lectin array has been developed to probe the interactions of innate immune receptors with pathogenic and commensal microorganisms. Following the successful introduction of a lectin array containing all of the cow C-type carbohydrate-recognition domains (CRDs), a human array described here contains the C-type CRDs as well as CRDs from other classes of sugar-binding receptors, including galectins, siglecs, R-type CRDs, ficolins, intelectins, and chitinase-like lectins. The array is constructed with CRDs modified with single-site biotin tags, ensuring that the sugar-binding sites in CRDs are displayed on a streptavidin-coated surface in a defined orientation and are accessible to the surfaces of microbes. A common approach used for expression and display of CRDs from all of the different structural categories of glycanbinding receptors allows comparisons across lectin families. In addition to previously documented protocols for binding of fluorescently labeled bacteria, methods have been developed for detecting unlabeled bacteria bound to the array by counterstaining with DNA-binding dye. Screening has also been undertaken with viral glycoproteins and bacterial and fungal polysaccharides. The array provides an unbiased screen for sugar ligands that interact with receptors and many show binding not anticipated from earlier studies. For example, some of the galectins bind with high affinity to bacterial glycans that lack lactose or N-acetyllactosamine. The results demonstrate the utility of the human lectin array for providing a unique overview of the interactions of multiple classes of glycanbinding proteins in the innate immune system with different types of microorganisms. [ABSTRACT FROM AUTHOR]

Enzyme replacement therapy (ERT) is the only approved disease-modifying treatment modality for Pompe disease, a rare, inherited metabolic disorder caused by a deficiency in the acid α-glucosidase (GAA) enzyme that catabolizes lysosomal glycogen. First-generation recombinant human GAA (rhGAA) ERT (alglucosidase alfa) can slow the progressive muscle degeneration characteristic of the disease. Still, most patients experience diminished efficacy over time, possibly because of poor uptake into target tissues. Next-generation ERTs aim to address this problem by increasing bis-phosphorylated high mannose (bis-M6P) N-glycans on rhGAA as these moieties have sufficiently high receptor binding affinity at the resultant low interstitial enzyme concentrations after dosing to drive uptake by the cationindependent mannose 6-phosphate receptor on target cells. However, some approaches introduce bis-M6P onto rhGAA via non-natural linkages that cannot be hydrolyzed by natural human enzymes and thus inhibit the endolysosomal glycan trimming necessary for complete enzyme activation after cell uptake. Furthermore, all rhGAA ERTs face potential inactivation during intravenous delivery (and subsequent non-productive clearance) as GAA is an acid hydrolase that is rapidly denatured in the near-neutral pH of the blood. One new therapy, cipaglucosidase alfa plus miglustat, is hypothesized to address these challenges by combining an enzyme enriched with naturally occurring bis-M6P N-glycans with a small-molecule stabilizer. Here, we investigate this hypothesis by analyzing published and new data related to the mechanism of action of the enzyme and stabilizer molecule. Based on an extensive collection of in vitro, preclinical, and clinical data, we conclude that cipaglucosidase alfa plus miglustat successfully addresses each of these challenges to offer meaningful advantages in terms of pharmacokinetic exposure, target-cell uptake, endolysosomal processing, and clinical benefit. [ABSTRACT FROM AUTHOR]

Complex respiratory diseases are a significant challenge for the livestock industry worldwide. These diseases considerably impact animal health and welfare and cause severe economic losses. One of the first lines of pathogen defense combines the respiratory tract mucus, a highly viscous material primarily composed of mucins, and a thriving multi-kingdom microbial ecosystem. The microbiome-mucin interplay protects from unwanted substances and organisms, but its dysfunction may enable pathogenic infections and the onset of respiratory disease. Emerging evidence also shows that noncoding regulatory RNAs might modulate the structure and function of the microbiome-mucin relationship. This opinion paper unearths the current understanding of the triangular relationship between mucins, the microbiome, and noncoding RNAs in the context of respiratory infections in animals of veterinary interest. There is a need to look at these molecular underpinnings that dictate distinct health and disease outcomes to implement effective prevention, surveillance, and timely intervention strategies tailored to the different epidemiological contexts.

Abstract The clinical diagnosis of major depressive disorder (MDD) still depends on subjective information in terms of various symptoms regarding mood. Detecting the characterization of extracellular vesicles (EVs) in blood may result in finding a diagnostic biomarker that reflects the depressive stage of patients with MDD. Here, we report the results on the glycosylation pattern of enriched plasma EVs from patients with MDD. We compared glycosylation patterns by lectin blotting expressed in EVs isolated from the plasma of both patients with MDD and age-matched healthy control participants (HCs) using size-exclusion chromatography. The levels of Wheat germ agglutinin (WGA), N-acetyl glucosamine (GlcNAc), and N-Acetylneuraminic acid (Neu5Ac, sialic acid) - binding lectin, were significantly decreased in patients with MDD in the depressive state compared to HCs and in remission state. Furthermore, proteome analysis revealed that the von Willebrand factor (vWF) was a significant factor recognized by WGA. WGA-binding vWF antigen differentiated patients with MDD versus HCs and the same patients with MDD in a depressive versus remission state. In this study, the change patterns in the glycoproteins contained in plasma EVs support the usability of testing to identify patients who are at increased risk of depression during antidepressant treatment.

Abstract Colorectal cancer (CRC) has a high mortality rate, resulting from the processes of metastasis and disease recurrence. Cancer stem cells (CSCs) are believed to be crucial for both processes, as they ensure the maintenance of the tumor bulk, in addition to being intrinsically resistant to conventional therapies. Thus, the present study aimed to investigate glycobiomarkers in colorectal cancer stem cell subpopulations. For this purpose, a sphere formation assay was standardized for CACO-2 and HT-29 cell lines, which were monitored through gene expression analysis of five known CSC markers (CD24, CD44, ALDH1, LGR5, and PROM1). Compared to the parental condition (2D), a reduction in CD24 expression was seen in CACO-2, while in HT-29 an increase in the expression levels of ALDH1, LGR5, and PROM1 was observed. Regarding glycogenes, eight of them (ST3GAL1, OGT, OGA, MGAT5, GFAT1, GFAT2, B4GALT1 e B3GNT2) have had their expression monitored. An increase in B3GNT2, OGT, and OGA was observed in the HT-29 sphere condition. On the other hand, no change in the glycogenes expression was observed in CACO-2. In silico correlation analyses (CSCs markers versus glycogenes) using TCGA data from colon and rectum carcinoma samples showed a weak positive correlation between LGR5 vs OGA expression regardless of the sample location. In addition, an increase in the expression of LGR5, OGA, and OGT as well as a decrease in the expression of ALDH1 were observed in colon carcinoma samples when compared to the adjacent normal tissue. Interestingly, greater OGA expression resulted in both lower overall survival of colon carcinoma patients and lower disease-free survival of rectum carcinoma patients. Therefore, our data indicates that OGA expression correlates with CSC markers and directly impacts the survival of colorectal carcinoma patients.

Abstract Human immunodeficiency virus type 1 (HIV-1) vaccine immunogens capable of inducing broadly neutralizing antibodies (bNAbs) remain obscure. HIV-1 evades immune responses through enormous diversity and hides its conserved vulnerable epitopes on the envelope glycoprotein (Env) by displaying an extensive immunodominant glycan shield. In elite HIV-1 viremic controllers, glycan-dependent bNAbs targeting conserved Env epitopes have been isolated and are utilized as vaccine design templates. However, immunological tolerance mechanisms limit the development of these antibodies in the general population. The well characterized bNAbs monoclonal variants frequently exhibit extensive levels of somatic hypermutation, a long third heavy chain complementary determining region, or a short third light chain complementarity determining region, and some exhibit poly-reactivity to autoantigens. This review elaborates on the obstacles to engaging and manipulating the Env glycoprotein as an effective immunogen and describes an alternative reverse vaccinology approach to develop a novel category of bNAb-epitope-derived non-cognate immunogens for HIV-1 vaccine design. Graphical Abstract

Glycosylation, a crucial posttranslational modification, plays a significant role in numerous physiological and pathological processes. Lectin microarrays, which leverage the high specificity of lectins for sugar binding, are ideally suited for profiling the glycan spectra of diverse and complex biological samples. In this review, we explore the evolution of lectin detection technologies, as well as the applications and challenges of lectin microarrays in analyzing the glycome profiles of various clinical samples, including serum, saliva, tissues, sperm, and urine. This review not only emphasizes significant advancements in the high-throughput analysis of polysaccharides but also provides insight into the potential of lectin microarrays for diagnosing and managing diseases such as tumors, autoimmune diseases, and chronic inflammation. We aim to provide a clear, concise, and comprehensive overview of the use of lectin microarrays in clinical settings, thereby assisting researchers in conducting clinical studies in glycobiology.

Endometriosis is a chronic systemic disease, which results in endometrial-type tissue growing outside the uterus, and affects approximately 10% of reproductive-aged women worldwide. Its aetiology is poorly understood, and there is currently no long-term cure. Development and persistence of the disease depend on several coexisting factors including the vaginal microbiome. However, the role played by this important entity in endometriosis and its systemic involvement is not fully understood. Here, we investigated the vaginal microbiota, the serum and urine glycome, and antibody glycosylation in endometriosis patients. We reveal an endometriosis-specific vaginal microbiota in patients, being distinct from that present in a control group. Endometriosis patients were typified by a loss of the dominant Lactobacillus species, i.e. Lactobacillus iners, increased bacterial diversity and the presence of species such as Anaerococcus senegalensis, Prevotella jejuni, Porphyromonas bennonis and Anaerococcus octavius. The presence of trigalactosylated and triantennary serum glycans and urine core fucosylated mono-antennary glycans from IgG correlated with the vaginal presence of the bacterium A. senegalensis in endometriosis patients. Urine glycans did not differ in endometriosis, but urine IgG identified four novel sulfated glycans differing from serum IgG indicating functional relevance. Our findings contribute to understanding the relationships between the vaginal microbiota and the serum and urine glycome on the one hand, and endometriosis on the other. Further functional studies are warranted. [ABSTRACT FROM AUTHOR]

This report describes the development and characterization of a comprehensive collection of CHO cell glycosylation mutants with significant potential for advancing glycobiology and biotechnology. EPO-Fc and trastuzumab, two model molecules, were produced using these mutants to assess the effects of mutated glycogenes, and LC-MS/MS analysis was employed to quantitatively analyse their N-glycans. EPO-Fc exhibited exclusively homogeneous Man9 glycans only when nearly all α-mannosidases in the genome were inactivated, except lysosomal MAN2B1. Some mutants lacking GnT-I activity produce mostly Man5 N-glycans, while their O-glycan and glycolipid profiles can differ due to other mutations in the cell. GnT-II deficiency prevents GnT-V from adding GlcNAc to the core N-glycan, resulting in branches attaching solely to the α1,3-linked mannose, leaving the α1,6-linked mannose free. The mutant-produced antibody's single-branched glycan contains more sialic acid than the dual-branched glycans produced in CHO-K1 cells. Trastuzumab produced in these mutants provided insights into how Fc N-glycans impact the antibody's interaction with FcγR1 and FcγR2a, FcγR3a, and their influence on antibody-dependent cellular cytotoxicity (ADCC). In the study of Fc glycans in Fc-FcγR1 and FcγR2a interactions, we observed a consistent glycan-related impact on binding to both receptors, indicating a common interaction mechanism between Fc glycans and both FcγRI and FcγRIIa. CHO mutants produced trimeric gp120 demonstrated distinct reactivity with multiple broadly neutralizing anti-HIV antibodies, confirming the involvement of gp120 glycans in interactions with specific broadly neutralizing antibodies. Finally, one of the mutants produced human β-glucocerebrosidase with uniform Man5 N-glycans, showcasing its potential for glycoengineered production and enhancement in therapeutic efficacy. [ABSTRACT FROM AUTHOR]

Cell surface glycans form various "glycan patterns" consisting of different types of glycan molecules, thus enabling strong and selective cell-to-cell recognition. We previously conjugated different N-glycans to human serum albumin to construct glycoalbumins mimicking natural glycan patterns that could selectively recognize target cells or control excretion pathways in mice. Here, we develop an innovative glycoalbumin capable of undergoing transformation and remodeling of its glycan pattern in vivo, which induces its translocation from the initial target to a second one. Replacing α(2,3)-sialylated N-glycans on glycoalbumin with galactosylated glycans induces the translocation of the glycoalbumin from blood or tumors to the intestine in mice. Such "in vivo glycan pattern remodeling" strategy can be used as a drug delivery system to promote excretion of a drug or medical radionuclide from the tumor after treatment, thereby preventing prolonged exposure leading to adverse effects. Alternatively, this study provides a potential strategy for using a single glycoalbumin for the simultaneous treatment of multiple diseases in a patient. Cell surface glycans form glycan patterns consisting of different types of glycan molecules, thus enabling strong and selective cell-to-cell recognition. In this study, the authors report a method based on the manipulation of glycan patterns to translocate a glycosylated albumin from blood or tumor to intestine by remodeling the α(2,3)-sialylated glycan pattern into a galactosylated pattern on albumin via a bioorthogonal chemical reaction. [ABSTRACT FROM AUTHOR]

Background: Abnormal glycosylation is associated with tumors. The clinical value of serum glycans in assessing progression of hepatocellular carcinoma (HCC) patients remains a challenge. Methods: A study dynamically comparing levels of fifteen lectin‐specific glycans between preoperative and postoperative serum of 65 HCC patients was conducted via lectin biochip technology. Multivariable logistic regression analysis was used to address associations between serum glycan levels and clinicopathological characteristics. Kaplan–Meier analysis was used to evaluate the impacts of serum glycan levels on overall survival (OS) and progression‐free survival (PFS) of the HCC patients. Results: HCC patients presented significantly higher levels of the lectin‐specific glycans in preoperative serum than disease‐free individuals (p < 0.001 − p = 0.029), except ConA. The glycans in preoperative sera were significantly related to tumor size, pTNM, metastasis, BCLC stage, portal hypertension (PHT), and platelet count (PLT), respectively (p < 0.05). Multivariate logistic analyses indicated that tumor size and pTNM independently impact on glycan‐specific lectins either LTL, UEA‐I, VVL, NPL, WGA, PNA, MAL‐I, SNA, or PHA‐L (p = 0.003 − p = 0.044); BCLC stage and PLT were independent factors influencing the serum glycans recognizable DSA (p = 0.024) and SNA (p = 0.050), respectively. Surgical excision of tumor mass significantly reduced glycan levels in sera. Tumor differentiation, albumin, and ABO type significantly revealed independent influence on glycan‐specific lectins, such as RCA‐I (p = 0.024), VVL (p = 0.024), and Con A (p = 0.026) in the postoperative serum. HCC patients with high levels of VVL‐binding glycans significantly benefited from a longer OS time (p = 0.016, HR: 0.460, 95% CI: 0.237–0.892) and a better PFS time (p = 0.004; HR: 0.435, 95% CI: 0.237–0.799), respectively. Conclusion: Serum glycans could reflect surgical outcomes in at‐risk patients and become valuable biomarkers in evaluating the progression of HCC patients. [ABSTRACT FROM AUTHOR]

The widespread application of enzymes in industrial chemical synthesis requires efficient process control to maintain high yields and purity. Flow injection analysis-electrospray ionization-mass spectrometry (FIA-ESI–MS) offers a promising solution for real-time monitoring of these enzymatic processes, particularly when handling challenging compounds like sugars and glycans, which are difficult to quickly analyze using liquid chromatography-mass spectrometry due to their physical properties or the requirement for a derivatization step beforehand. This study compares the performance of FIA-MS with traditional hydrophilic interaction liquid chromatography (HILIC)-ultra high-performance liquid chromatography (UHPLC)-mass spectrometry (MS) setups for the monitoring of the enzymatic synthesis of N-acetyllactosamine (LacNAc) using beta-1,4-galactosyltransferase. Our results show that FIA-MS, without prior chromatographic separation or derivatization, can quickly generate accurate mass spectrometric data within minutes, contrasting with the lengthy separations required by LC–MS methods. The rapid data acquisition of FIA-MS enables effective real-time monitoring and adjustment of the enzymatic reactions. Furthermore, by eliminating the derivatization step, this method offers the possibility of being directly coupled to a continuously operated reactor, thus providing a rapid on-line methodology for glycan synthesis as well. [ABSTRACT FROM AUTHOR]

Lectin-based approaches remain a valuable tool for analyzing glycosylation, especially when detecting cancer-related changes. Certain glycans function as platforms for cell communication, signal transduction, and adhesion. Therefore, the functions of glycans are important considerations for clinical aspects, such as cancer, infection, and immunity. Considering that the three-dimensional structure and multivalency of glycans are important factors for their function, their binding characteristics toward lectins provide vital information. Glycans and lectins are inextricably linked, and studies on lectins have also led to research on the roles of glycans. The applications of lectins are not limited to analysis but can also be used as drug delivery tools. Moreover, mammalian lectins are potential therapeutic targets because certain lectins change their expression in cancer, and lectin regulation subsequently regulates several molecules with glycans. Herein, we review lectin-based approaches for analyzing the role of glycans and their clinical applications in diseases, as well as our recent results. [ABSTRACT FROM AUTHOR]

Human complement factor H (CFH) plays a central role in regulating activated C3b to protect host cells. CFH contain 20 short complement regulator (SCR) domains and eight N-glycosylation sites. The N-terminal SCR domains mediate C3b degradation while the C-terminal CFH domains bind to host cell surfaces to protect these. Our earlier study of Pichia-generated CFH fragments indicated a self-association site at SCR-17/18 that comprises a dimerization site for human factor H. Two N-linked glycans are located on SCR-17 and SCR-18. Here, when we expressed SCR-17/18 without glycans in an Escherichia coli system, analytical ultracentrifugation showed that no dimers were now formed. To investigate this novel finding, full-length CFH and its C-terminal fragments were purified from human plasma and Pichia pastoris respectively, and their glycans were enzymatically removed using PNGase F. Using size-exclusion chromatography, mass spectrometry, and analytical ultracentrifugation, SCR-17/18 from Pichia showed notably less dimer formation without its glycans, confirming that the glycans are necessary for the formation of SCR-17/18 dimers. By surface plasmon resonance, affinity analyses interaction showed decreased binding of deglycosylated full-length CFH to immobilized C3b, showing that CFH glycosylation enhances the key CFH regulation of C3b. We conclude that our study revealed a significant new aspect of CFH regulation based on its glycosylation and its resulting dimerization. [ABSTRACT FROM AUTHOR]

Studies have revealed the dependence of glioma cells on iron, making them sensitive to ferroptosis. Ferroptosis can be triggered by inhibition of the xc- system, resulting in redox imbalance and membrane lipid peroxidation. The xc- system is composed of two coupled proteins, xCT and CD98hc. The control of transporters, such as xCT, by the CD98hc glycoprotein suggests that molecules targeting glycans may have an impact on the treatment of glioma. This study evaluated the effect of the Canavalia brasiliensis (ConBr) lectin on C6 glioma cells and compared it with erastin, an xc- system inhibitor. Both induced dose-dependent cell death, accompanied by an increase in the production of reactive oxygen species and a decrease in reduced glutathione. However, co-treatment did not show an additive effect. The analysis was updated by molecular dynamics assessments of the xc- system interacting with ConBr or erastin. The interaction of erastin with the xc- system affects its interaction with ConBr, reducing the antagonistic effect when both are in the protein complex. The data show that ConBr is effective in inducing cell death in glioma cells and regulates the xc system through interaction with CD98hc glycans, showing that lectins have the potential to promote ferroptosis in glioma cells. [ABSTRACT FROM AUTHOR]

Gastric mucins serve as a protective barrier on the stomach's surface, protecting from external stimuli including gastric acid and gut microbiota. Their composition typically changes in response to the metaplastic sequence triggered by Helicobacter pylori infection. This alteration in gastric mucins is also observed in cases of gastric cancer, although the precise connection between mucin expressions and gastric carcinogenesis remains uncertain. This review first introduces the relationship between mucin expressions and gastric metaplasia or cancer observed in humans and mice. Additionally, we discuss potential pathogenic mechanisms of how aberrant mucins and their glycans affect gastric carcinogenesis. Finally, we summarize challenges to target tumor‐specific glycans by utilizing lectin‐drug conjugates that can bind to specific glycans. Understanding the correlation and mechanism between these mucin expressions and gastric carcinogenesis could pave the way for new strategies in gastric cancer treatment. [ABSTRACT FROM AUTHOR]

Real-time tracking of intracellular carbohydrates remains challenging. While click chemistry allows bio-orthogonal tagging with fluorescent probes, the reaction permanently alters the target molecule and only allows a single snapshot. Here, we demonstrate click-free mid-infrared photothermal (MIP) imaging of azide-tagged carbohydrates in live cells. Leveraging the micromolar detection sensitivity for 6-azido-trehalose (TreAz) and the 300-nm spatial resolution of MIP imaging, the trehalose recycling pathway in single mycobacteria, from cytoplasmic uptake to membrane localization, is directly visualized. A peak shift of azide in MIP spectrum further uncovers interactions between TreAz and intracellular protein. MIP mapping of unreacted azide after click reaction reveals click chemistry heterogeneity within a bacterium. Broader applications of azido photothermal probes to visualize the initial steps of the Leloir pathway in yeasts and the newly synthesized glycans in mammalian cells are demonstrated. [ABSTRACT FROM AUTHOR]

Human immunodeficiency virus type 1 (HIV-1) vaccine immunogens capable of inducing broadly neutralizing antibodies (bNAbs) remain obscure. HIV-1 evades immune responses through enormous diversity and hides its conserved vulnerable epitopes on the envelope glycoprotein (Env) by displaying an extensive immunodominant glycan shield. In elite HIV-1 viremic controllers, glycan-dependent bNAbs targeting conserved Env epitopes have been isolated and are utilized as vaccine design templates. However, immunological tolerance mechanisms limit the development of these antibodies in the general population. The well characterized bNAbs monoclonal variants frequently exhibit extensive levels of somatic hypermutation, a long third heavy chain complementary determining region, or a short third light chain complementarity determining region, and some exhibit poly-reactivity to autoantigens. This review elaborates on the obstacles to engaging and manipulating the Env glycoprotein as an effective immunogen and describes an alternative reverse vaccinology approach to develop a novel category of bNAb-epitope-derived non-cognate immunogens for HIV-1 vaccine design. [ABSTRACT FROM AUTHOR]

Proteoglycans (PGs), which have glycosaminoglycan chains attached to their protein cores, are essential for maintaining the morphology and function of healthy body tissues. Extracellular PGs perform various functions, classified into the following four categories: i) the modulation of tissue mechanical properties; ii) the regulation and protection of the extracellular matrix; iii) protein sequestration; and iv) the regulation of cell signaling. The depletion of PGs may significantly impair tissue function, encompassing compromised mechanical characteristics and unregulated inflammatory responses. Since PGs play critical roles in the function of healthy tissues and their synthesis is complex, the development of PG mimetic molecules that recapitulate PG functions for tissue engineering and therapeutic applications has attracted the interest of researchers for more than 20 years. These approaches have ranged from semisynthetic graft copolymers to recombinant PG domains produced by cells that have undergone genetic modifications. This review discusses some essential extracellular PG functions and approaches to mimicking these functions. [ABSTRACT FROM AUTHOR]

The presence and the level of antibodies in human sera against bacterial glycans are indications of prior encounters with similar antigens and/or the bacteria that express them by the immune system. An increasing number of pathogenic bacteria that cause human diseases have been shown to express polysaccharides containing a bacterial nonulosonic acid called 5,7-di-N-acetyllegionaminic acid (Leg5,7Ac2). To investigate the immune recognition of Leg5,7Ac2, which is critical for the fight against bacterial infections, a highly effective chemoenzymatic synthon strategy was applied to construct a library of α2–3/6-linked Leg5,7Ac2-glycans via their diazido-derivatives (Leg5,7diN3-glycans) formed by efficient one-pot three-enzyme (OP3E) synthetic systems from a diazido-derivative of a six-carbon monosaccharide precursor. Glycan microarray studies using this synthetic library of a Leg5,7Ac2-capped collection of diverse underlying glycan carriers and their matched sialoside counterparts revealed specific recognition of Leg5,7Ac2 by human IgG antibodies pooled from thousands of healthy donors (IVIG), suggesting prior human encounters with Leg5,7Ac2-expressing pathogenic bacteria at the population level. These biologically relevant Leg5,7Ac2-glycans and their immune recognition assays are important tools to begin elucidating their biological roles, particularly in the context of infection and host–pathogen interactions. [ABSTRACT FROM AUTHOR]

Surface coatings with polyethylene glycol (PEG) polymers have often been employed to improve nanoparticles (NPs) biocompatibility and extend circulation time by reducing protein adsorption. PEGylated NPs benefit from steric hindrance and repulsion effects, which are influenced by PEG molecular weight, density, and chain conformation. However, repetitive exposure to PEG can trigger acute and chronic immunological responses as a result of the development of Immunoglobulin G anti-PEG antibodies. NPs functionalisation with glycans has become an emerging approach to increase their biocompatibility as these biomolecules are highly hydrophilic, biocompatible interact with biological receptors expressed in the body, and can be conjugated, controlling their orientation. In this study, we developed a series of gold NPs (AuNPs) coated with PEG linkers of different lengths and conjugated with mannose (Man) or sialic acid (Sia) glycans, and we carried out a detailed characterisation prior to and after exposure to biological fluids to study their behaviour and protein corona formation. Our findings show that the glycan-coated NPs exhibit stabilisation after protein interaction, with Man coatings showing the lowest protein affinity and that the glycans are biologically active and capable of binding to glycan receptors (such as Concanavalin A) despite the presence of a complex protein environment. Results indicate that glycan modification of PEGylated NPs reduces nonspecific interactions while preserving active targeting properties, underscoring their potential for therapeutic applications.

Chemical-nose/tongue technologies are emerging as promising analytical tools for glycan analysis. After briefly introducing the importance of glycans and their analytical methods, including the lectin microarray (LMA) as one of the gold standards, the fundamental principles underlying chemical noses/tongues are explained and various applications for monosaccharides and glycans are introduced. Then, the similarities and differences of these two approaches are discussed. While both technologies aim to comprehensively profile biospecimens based on ‘interaction patterns’ between multiple recognition probes and analytes, each has its own strengths. LMAs excel at specific, targeted analysis based on defined lectin–glycan interactions, whereas chemical nose/tongue offers greater flexibility and expandability in terms of system design, making it well-suited for discovering unknown glycan profiles and detecting broader differences in glycan mixtures. In the future, chemical-nose/tongue technologies may be applied to niche areas in glycan analysis and become powerful tools that complement LMA techniques.

Infection with the protozoan parasite Giardia duodenalis (syn. intestinalis, lamblia) has been associated with intestinal mucus disruptions and microbiota dysbiosis. The mechanisms remain incompletely understood. Mucus consists primarily of densely glycosylated mucin glycoproteins. Mucin O-glycans influence mucus barrier properties and mucin–microbe interactions and are frequently altered during disease. In this study, we observed time-dependent and regiospecific alterations to intestinal mucin glycosylation patterns and the expression of mucin-associated glycosyltransferase genes during Giardia infection. Glycosylation alterations were observed in Giardia-infected mice in the upper small intestine, the site of parasite colonization, and in the distal colon, where active trophozoites were absent. Alterations occurred as early as day 2 post-infection and persisted in mice after parasite clearance. We also observed small intestinal goblet cell hyperplasia and thinning of the distal colon mucus barrier during early infection, and microbiota alterations and altered production of cecal SCFAs. Giardia-induced alterations to mucin glycosylation were at least in part dependent on microbiota dysbiosis, as transplantation of a dysbiotic mucosal microbiota collected from Giardia-infected mice recapitulated some alterations. This study describes a novel mechanism by which Giardia alters intestinal mucin glycosylation, and implicates the small intestinal microbiota in regulation of mucin glycosylation patterns throughout the gastrointestinal tract.

The Golgi apparatus serves multiple crucial roles in the cell. These roles include the addition and subsequent modification of glycans, not only to newly-made proteins arriving from the endoplasmic reticulum, but also to precursors during the biosynthesis of glycolipids. New research by Brauer et al, (2024) now provides a conceptual framework that connects the use of glycosylation as a protein targeting signal with its use as a marker for Golgi quality control. A new study shows how a Golgi-resident protein is sent to the lysosome for degradation. [ABSTRACT FROM AUTHOR]

Nonulosonic acids or non-2-ulosonic acids (NulOs) are an ancient family of 2-ketoaldonic acids (α-ketoaldonic acids) with a 9-carbon backbone. In nature, these monosaccharides occur either in a 3-deoxy form (referred to as sialic acids) or in a 3,9-dideoxy sialic-acid-like form. The former sialic acids are most common in the deuterostome lineage, including vertebrates, and mimicked by some of their pathogens. The latter sialic-acid-like molecules are found in bacteria and archaea. NulOs are often prominently positioned at the outermost tips of cell surface glycans, and have many key roles in evolution, biology and disease. The diversity of stereochemistry and structural modifications among the NulOs contributes to more than 90 sialic acid forms and 50 sialic-acid-like variants described thus far in nature. This paper reports the curation of these diverse naturally occurring NulOs at the NCBI sialic acid page (https://www.ncbi.nlm.nih.gov/glycans/sialic.html) as part of the NCBI-Glycans initiative. This includes external links to relevant Carbohydrate Structure Databases. As the amino and hydroxyl groups of these monosaccharides are extensively derivatized by various substituents in nature, the Symbol Nomenclature For Glycans (SNFG) rules have been expanded to represent this natural diversity. These developments help illustrate the natural diversity of sialic acids and related NulOs, and enable their systematic representation in publications and online resources.

Bifidobacteria are commonly encountered members of the human gut microbiota that possess the enzymatic machinery necessary for the metabolism of certain plant-derived, complex carbohydrates. In the current study we describe differential growth profiles elicited by a panel of 21 newly isolated Bifidobacterium pseudocatenulatum strains on various plant-derived glycans. Using a combination of gene-trait matching and comparative genome analysis, we identified two distinct xylanases responsible for the degradation of xylan. Furthermore, three distinct extracellular α-amylases were shown to be involved in starch degradation by certain strains of B. pseudocatenulatum. Biochemical characterization showed that all three a-amylases can cleave the related substrates amylose, amylopectin, maltodextrin, glycogen and starch. The genes encoding these enzymes are variably found in the species B. pseudocatenulatum, therefore constituting a strain-specific adaptation to the gut environment as these glycans constitute common plant-derived carbohydrates present in the human diet. Overall, our study provides insights into the metabolism of these common dietary carbohydrates by a human-derived bifidobacterial species. [ABSTRACT FROM AUTHOR]

Organoboron compounds have a wide range of applications in numerous research fields, and methods to incorporate them in biomolecules are much sought after. Here, on‐resin chemical syntheses of aliphatic and vinylogous peptide boronic acids are presented by transition metal‐catalyzed late‐stage hydroboration of alkene and alkyne groups in peptides and peptoids, for example on allyl‐ and propargylglycine residues, using readily available chemicals. These methods yield peptide boronic acids with much shorter linkers than previously reported on‐resin methods. Furthermore, the methods are regio‐ and stereoselective, compatible with all canonical amino acid residues and can be applied to short, long, and in part even "difficult" peptide sequences. In a feasibility study, the protected peptide vinylboronic acids are further derivatized by the Petasis reaction using salicylaldehyde derivatives. The ability of the obtained peptide boronic acids to reversibly bind to carbohydrates is demonstrated in a catch‐release model experiment using a fluorescently labeled peptide boronic acid on cross‐linked dextran beads. In summary, this highlights the potential of the target compounds for drug discovery, glycan‐specific target recognition, controlled release, and diagnostics. [ABSTRACT FROM AUTHOR]

The study of glycoproteomics presents a set of unique challenges, primarily due to the low abundance of glycopeptides and their intricate heterogeneity, which is specific to each site. Glycoproteins play a crucial role in numerous biological functions, including cell signaling, adhesion, and intercellular communication, and are increasingly recognized as vital markers in the diagnosis and study of various diseases. Consequently, a quantitative approach to glycopeptide research is essential. One effective strategy to address this need is the use of multiplex glycopeptide labeling. By harnessing the synergies of 15N metabolic labeling via the isotopic detection of amino sugars with glutamine (IDAWG) technique for glycan parts and tandem mass tag (TMT)pro labeling for peptide backbones, we have developed a method that allows for the accurate quantification and comparison of multiple samples simultaneously. The adoption of the liquid chromatography-synchronous precursor selection (LC-SPS-MS3) technique minimizes fragmentation interference, enhancing data reliability, as shown by a 97% TMT labeling efficiency. This method allows for detailed, high-throughput analysis of 32 diverse samples from 231BR cell lines, using both 14N and 15N glycopeptides at a 1:1 ratio. A key component of our methodology was the precise correction for isotope and TMTpro distortions, significantly improving quantification accuracy to less than 5% distortion. This breakthrough enhances the efficiency and accuracy of glycoproteomic studies, increasing our understanding of glycoproteins in health and disease. Its applicability to various cancer cell types sets a new standard in quantitative glycoproteomics, enabling deeper investigation into glycopeptide profiles. [ABSTRACT FROM AUTHOR]

Mucus stasis is a pathologic hallmark of muco-obstructive diseases, including cystic fibrosis (CF). Mucins, the principal component of mucus, are extensively modified with hydroxyl (O)-linked glycans, which are largely terminated by sialic acid. Sialic acid is a negatively charged monosaccharide and contributes to the biochemical/biophysical properties of mucins. Reports suggest that mucin sialylation may be altered in CF; however, the consequences of reduced sialylation on mucus clearance have not been fully determined. Here, we investigated the consequences of reduced sialylation on the charge state and conformation of the most prominent airway mucin, MUC5B, and defined the functional consequences of reduced sialylation on mucociliary transport (MCT). Reduced sialylation contributed to a lower charged MUC5B form and decreased polymer expansion. The inhibition of total mucin sialylation de novo impaired MCT in primary human bronchial epithelial cells and rat airways, and specific α-2,3 sialylation blockade was sufficient to recapitulate these findings. Finally, we show that ST3 beta-galactoside alpha-2,3-sialyltransferase (ST3Gal1) expression is downregulated in CF and partially restored by correcting CFTR via Elexacaftor/Tezacaftor/Ivacaftor treatment. Overall, this study demonstrates the importance of mucin sialylation in mucus clearance and identifies decreased sialylation by ST3Gal1 as a possible therapeutic target in CF and potentially other muco-obstructive diseases. [ABSTRACT FROM AUTHOR]

Immunodominance of antibodies targeting non-neutralizing epitopes and the high level of somatic hypermutation within germinal centers (GCs) required for most HIV broadly neutralizing antibodies (bnAbs) are major impediments to the development of an effective HIV vaccine. Rational protein vaccine design and non-conventional immunization strategies are potential avenues to overcome these hurdles. Here, we report using implantable osmotic pumps to continuously deliver a series of epitope-targeted immunogens to rhesus macaques over the course of six months to prime and elicit antibody responses against the conserved fusion peptide (FP). GC responses and antibody specificities were tracked longitudinally using lymph node fine-needle aspirates and electron microscopy polyclonal epitope mapping (EMPEM), respectively, to show antibody responses to the FP/N611 glycan hole region were primed, although exhibited limited neutralization breadth. Application of cryoEMPEM delineated key residues for on-target and off-target responses that can drive the next round of structure-based vaccine design. [ABSTRACT FROM AUTHOR]

The swimming device of archaea—the archaellum—presents asparagine (N)-linked glycans. While N-glycosylation serves numerous roles in archaea, including enabling their survival in extreme environments, how this post-translational modification contributes to cell motility remains under-explored. Here, we report the cryo-EM structure of archaellum filaments from the haloarchaeon Halobacterium salinarum, where archaellins, the building blocks of the archaellum, are N-glycosylated, and the N-glycosylation pathway is well-resolved. We further determined structures of archaellum filaments from two N-glycosylation mutant strains that generate truncated glycans and analyzed their motility. While cells from the parent strain exhibited unidirectional motility, the N-glycosylation mutant strain cells swam in ever-changing directions within a limited area. Although these mutant strain cells presented archaellum filaments that were highly similar in architecture to those of the parent strain, N-linked glycan truncation greatly affected interactions between archaellum filaments, leading to dramatic clustering of both isolated and cell-attached filaments. We propose that the N-linked tetrasaccharides decorating archaellins act as physical spacers that minimize the archaellum filament aggregation that limits cell motility. The archaellum, or archaeal 'flagellum', includes asparagine-linked glycans that are important for efficient cell motility in archaea through unclear mechanisms. Here, the authors show that glycan truncation leads to clustering of filaments and alterations in cell motility, suggesting that the glycans minimize archaellum filament aggregation that compromises cell motility. [ABSTRACT FROM AUTHOR]

Glycans participate in a vast number of recognition systems in diverse organisms in health and in disease. However, glycans cannot be sequenced because there is no sequencer technology that can fully characterize them. There is no "template" for replicating glycans as there are for amino acids and nucleic acids. Instead, glycans are synthesized by a complicated orchestration of multitudes of glycosyltransferases and glycosidases. Thus glycans can vary greatly in structure, but they are not genetically reproducible and are usually isolated in minute amounts. To characterize (sequence) the glycome (defined as the glycans in a particular organism, tissue, cell, or protein), glycosylation pathway prediction using in silico methods based on glycogene expression data, and glycosylation simulations have been attempted. Since many of the mammalian glycogenes have been identified and cloned, it has become possible to predict the glycan biosynthesis pathway in these systems. By then incorporating systems biology and bioprocessing technologies to these pathway models, given the right enzymatic parameters including enzyme and substrate concentrations and kinetic reaction parameters, it is possible to predict the potentially synthesized glycans in the pathway. This review presents information on the data resources that are currently available to enable in silico simulations of glycosylation and related pathways. Then some of the software tools that have been developed in the past to simulate and analyze glycosylation pathways will be described, followed by a summary and vision for the future developments and research directions in this area. [ABSTRACT FROM AUTHOR]

Background: Patterns of humoral immune responses represent a major hurdle in terms of pig-to-human xenotransplantation approaches. The best-known xenogeneic glycan antigens present in pigs are the αGal (Galili antigen) and the non-human sialic acid Neu5Gc. As there are further differences between porcine and human cellular surface glycosylation, a much broader range of glycan epitopes with xeno-reactive relevance can be anticipated. Therefore, we set out to chemically modify porcine cellular surface glycans in a global approach by applying sodium periodate (NaIO4) oxidation. Methods: Porcine endothelial cells were exposed to oxidation with 1 to 5 mM NaIO4 for different time periods at 37 °C or 4 °C and under static or dynamic conditions. The impact on cellular survival was determined by applying live/dead assays. Oxidation of αGal-epitopes was assessed by fluorescence microscopy-based quantification of isolectin-B4 (IL-B4) staining. Overall immunogenicity of porcine cells was determined by human serum antibody binding. Results: Treatment of porcine endothelial cells and tissues with NaIO4 led to reduced binding of the αGal-specific IL-B4 and/or human serum antibodies. NaIO4 was revealed to be cytotoxic when performed at elevated temperatures and for a prolonged time. However, by applying 2 mM NaIO4 for 60 min at 4 °C, a high extent of cellular viability and a relevant reduction in detectable αGal epitope were observed. No differences were detected irrespectively on whether the cells were oxidized under static or flow conditions. Conclusions: Glycan epitopes on living cells can be oxidized with NaIO4 while maintaining their viability. Accordingly, this strategy holds promise to prevent immune reactions mediated by preformed anti-glycan antibodies. [ABSTRACT FROM AUTHOR]

Glycosylated derivatives of natural product polyphenols display a spectrum of biological activities, rendering them critical for both nutritional and pharmacological applications. Their enzymatic synthesis by glycosyltransferases is frequently constrained by the limited repertoire of characterized enzyme-catalyzed transformations. Here, we explore the glycosylation capabilities and substrate preferences of newly identified plant uridine diphosphate (UDP)-dependent glycosyltransferases (UGTs) within the UGT72 and UGT84 families, with particular focus on natural polyphenol glycosylation from UDP-glucose. Four UGTs are classified according to their phylogenetic relationships and reaction products, identifying them as biocatalysts for either glucoside (UGT72 enzymes) or glucose ester (UGT84 members) formation from selected phenylpropanoid compounds. Detailed kinetic evaluations expose the unique attributes of these enzymes, including their specific activities and regio-selectivities towards diverse polyphenolic substrates, with product characterizations validating the capacity of UGT84 family members to perform di-O-glycosylation on flavones. Sequence analysis coupled with structural predictions through AlphaFold reveal an unexpected absence of a conserved threonine residue across all four enzymes, a trait previously linked to pentosyltransferases. This comparative analysis broadens the understood substrate specificity range for UGT72 and UGT84 enzymes, enhancing our understanding of their utility in the production of natural phenolic glycosides. The findings from this in-depth characterization provide valuable insights into the functional versatility of UGT-mediated reactions. Uridine diphosphate-dependent glycosyltransferases (UGTs) play a vital role in the biocatalytic glycosylation of phenolic compounds, however, UGT-catalyzed transformations remain not well-characterized. Here, the authors investigate new members of UGT72 and UGT84 families, revealing their specific reactivity and regio-selectivity on selected polyphenolic substrates. [ABSTRACT FROM AUTHOR]

Glycans are complex biomolecules that encode rich information and regulate various biological processes, such as fertilization, host‐pathogen binding, and immune recognition, through interactions with glycan‐binding proteins. A key driving force for glycan‐protein recognition is the interaction between the π electron density of aromatic amino acid side chains and polarized C─H groups of the pyranose (termed the CH–π interaction). However, the relatively weak binding affinity between glycans and proteins has hindered the application of glycan detection and imaging. Here, computational modeling and molecular dynamics simulations are employed to design a chemical strategy that enhances the CH–π interaction between glycans and proteins by genetically incorporating electron‐rich tryptophan derivatives into a lectin PhoSL, which specifically recognizes core fucosylated N‐linked glycans. This significantly enhances the binding affinity of PhoSL with the core fucose ligand and enables sensitive detection and imaging of core fucosylated glycans in vitro and in xenograft tumors in mice. Further, the study showed that this strategy is applicable to improve the binding affinity of GafD lectin for N‐acetylglucosamine‐containing glycans. The approach thus provides a general and effective way to manipulate glycan‐protein recognition for glycoscience applications. [ABSTRACT FROM AUTHOR]