Search Results (584)

O-linked glycosylation comprises distinct regulatory systems, including secretory-pathway mucin-type O-GalNAc glycosylation and intracellular O-GlcNAcylation. These modifications both target serine/threonine residues but differ in glycan structure, cellular compartment, enzymatic machinery, and biological function. This narrative review was based on targeted searches of PubMed, Web of Science, and related literature using keywords related to O-glycosylation, O-GalNAc glycosylation, O-GlcNAcylation, immune regulation, cell signaling, glycoproteomics, and congenital disorders of glycosylation (CDG). We summarize evidence that mucin-type O-glycosylation regulates receptor behavior, cell adhesion, immune checkpoints, immunoglobulin function, antigen recognition, and pathogen–host interactions, whereas O-GlcNAcylation mainly modulates intracellular signaling, transcriptional control, stress responses, post-translational modification crosstalk, and innate immune pathways. We also discuss how glycosylation defects, including CDG and selected O-linked glycosylation disorders, connect genetic variation with disease phenotypes. Recent advances in site-specific glycoproteomics, O-glycoprotease-assisted workflows, LC–MS/MS-based glycopeptide analysis, and spatial or temporal profiling have improved mechanistic interpretation but still face limitations in site localization, structural resolution, and functional validation. Overall, the evidence supports the hypothesis that distinct O-linked glycosylation systems act through different molecular mechanisms but converge on signaling regulation, immune homeostasis, and disease susceptibility. Full article

Human milk is widely recognised as the optimal source of nutrition for newborns and infants, providing not only an ideal macronutrient composition but also a range of bioactive components that exert important non-nutritional functions, and as such it represents the first functional food consumed in early life. Among these bioactive components, the human milk oligosaccharides (HMOs)—a structurally diverse family of glycans present in human milk at concentrations 100- to 1000-fold higher than in the milk of other mammalian species—have emerged as multifunctional contributors to the establishment of the intestinal microbiome, immune development, anti-infective defence, and epithelial barrier integrity during a developmental window characterised by immune immaturity. The aim of the present narrative review is to synthesise current evidence on the anti-infective properties of HMOs in infancy and to integrate, within a single framework, five interconnected mechanisms through which HMOs protect the infant against infection: glycan-mimicry-based competitive inhibition of pathogen adhesion, direct antimicrobial and antibiofilm activity, selective prebiotic shaping of the gut microbiome, modulation of innate and adaptive immune responses, and reinforcement of mucosal barrier integrity in the gut and lungs. Breastfeeding constitutes a natural strategy for anti-infective protection in early childhood, while infant formulas supplemented with biotechnologically produced HMOs that are structurally identical to those in human milk provide measurable benefits for non-breastfed infants. Full article

Porcine enteric coronaviruses (PECs), including porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), porcine deltacoronavirus (PDCoV), and swine acute diarrhea syndrome coronavirus (SADS-CoV), remain major causes of neonatal diarrhea, dehydration, mortality, and economic loss in swine production. Despite substantial progress in vaccine development, durable field protection is still inconsistent. In this narrative review, this narrative review synthesizes current knowledge on PEC vaccine design from three connected perspectives: antigenic breadth, mucosal immunity, and translational evaluation. The economic and virological context of PEC vaccine development is first summarized, including the recurrent production burden of PECs, coronavirus genome organization, structural proteins, and the central role of the spike protein in receptor engagement, membrane fusion, and neutralizing antibody induction. Key issues are then discussed, including how spike diversity, conformational stability, epitope accessibility, glycan shielding, and antigen matching influence protective breadth; why intestinal secretory IgA, mucosal immune-cell trafficking, local memory responses, and lactogenic immunity should be prioritized as biologically relevant endpoints; and how delivery route, adjuvant selection, and platform design shape response quality. Current evidence on recombinant protein, viral-vectored, nanoparticle, virus-like particle, probiotic, plant-derived, and mRNA-based approaches is compared with attention to both promise and current evidentiary and translational limitations. The available literature suggests that future progress in PEC vaccinology is likely to depend less on platform novelty alone than on integrated vaccine designs that align antigen selection, mucosal delivery, maternal–neonatal protection, heterologous challenge, manufacturability, and field applicability. Full article

N-glycosylation, particularly terminal mannose exposure, is a critical quality attribute affecting macrophage targeting and the clinical efficacy of enzyme replacement therapy for Gaucher disease. This study developed a universal, sensitive, and quantitative method to compare the N-glycan profiles of three recombinant human glucocerebrosidase products from different expression systems: imiglucerase, velaglucerase alfa, and velaglucerase beta. Using 2-aminobenzamide labeling combined with HILIC-UPLC-FLD and high-resolution mass spectrometry, an N-glycan profiling platform was established. A multidimensional calibration system integrating retention time, glucose unit values, and mass-to-charge ratios was constructed, and collision-induced dissociation tandem MS was used to identify isomers and phosphorylated glycans. The method showed good specificity, linearity, precision, and accuracy. Glycan profiling revealed clear product-dependent differences: imiglucerase was enriched in core-fucosylated Man3 structures, velaglucerase alfa was dominated by Man9 and contained more phosphorylated and sialylated glycans, whereas velaglucerase beta showed a highly homogeneous Man5 profile. These findings demonstrate how distinct manufacturing strategies shape glycosylation patterns and provide a basis for biosimilar development and comparability assessment. Full article

Diet plays a critical role in shaping the composition of gut microbiota in insects. Samia ricini, an economically important Lepidoptera insect, is a polyphagous herbivore that offers a useful model for studying dietary effects on the animal gut microbiome. Here, we fed S. ricini larvae with different food plants, Ricinus communis, Ailanthus altissima, and Manihot esculenta leaves to investigate how host plant species influence growth performance, digestive enzyme activities, and the gut microbial community. Our results showed that the Ricinus group exhibited better growth performance. Regarding digestive enzymes, the midgut lipase activity was significantly higher in the Ricinus group than in the Ailanthus group, while no significant differences were observed in α-amylase, cellulase, or trypsin activities among the three groups. Compared to the Manihot group, the Ricinus group showed increased bacterial richness, while the Ailanthus group showed increased bacterial diversity. β-diversity analysis further revealed distinct microbial community structures among all three dietary groups. Specifically, Acinetobacter, Mammaliicoccus, Roseateles, Methylobacterium, Agrobacterium, Faecalibacterium, and Segatella were the dominant bacterial genera. Functional prediction revealed that gut microbes enriched in the Ricinus group were associated with terpenoid/polyketide metabolism, xenobiotics biodegradation, and glycan biosynthesis, whereas those involved in carbohydrate metabolism and biosynthesis of other secondary metabolites were higher in the Manihot group. Spearman correlation analysis indicated that Methylobacterium, Methylorubrum, and Agrobacterium were significantly positively correlated with larval weight, while Staphylococcus and Cyanothece_PCC-7424 exhibited negative correlations. Collectively, these findings suggest a potential association between different plant-derived diets, gut microbiota composition, and host growth performance, highlighting the pivotal role of diet in shaping insect gut microbial communities. Full article

Genomic analysis of various fish has advanced in recent years; however, predicting glycan information from the genomic data alone remains challenging. Glycomic techniques have therefore attracted considerable attention. In this study, we analyzed N- and O-glycans in unfertilized Oncorhynchus keta eggs using glycomic techniques, such as a glycoblotting procedure, a sialic acid linkage-specific alkylamidation, and an evaporative β-elimination with pyrazolone. N-Glycomic analysis revealed that biantennary N-glycans were predominant, and that sialylation occurred via an α2,3 linkage. In addition, numerous sulfated N-glycans were observed, some of which had not been reported previously. Tandem mass spectrometry analyses indicated that most of the sulfate groups were attached to GlcNAc linked to mannose within the core structure. The sulfation sites of the unknown sulfated glycans were the same; however, a GlcNAc residue was lost from the core structure. In O-glycomics, oligo-sialylated O-glycans, which contain between one to seven sialic acid residues, were observed in the unfertilized eggs. Most of the sialic acids in the O-glycans were Neu5Gc, and there was no α2,3 linkage. Full article

The selectin family constitutes a well-known class of immune-regulatory molecules, among which P-selectin has emerged as a therapeutic target for inflammatory thrombotic diseases due to its capacity to mediate the adhesion between multiple immune cell subsets and endothelial cells. Currently, small-molecule or glycomimetic inhibitors targeting P-selectin have stalled in Phase III clinical trials, with a common limitation being their weak binding affinity to P-selectin. In this study, in vitro competitive binding assays were employed to evaluate the inhibitory effects of structurally distinct fucosylated glycosaminoglycan (FG) oligosaccharides, derived from sea cucumbers, on the interaction between P-selectin and its ligands. A potent inhibitor, the nonasaccharide Ta-9-2 (featuring a novel disaccharide side chain), was identified. Biolayer interferometry (BLI) analysis further confirmed its high binding affinity to P-selectin, with a K_D of 83.92 nM. Structure–activity relationship (SAR) analysis reveals that the appropriate glycan chain length, the novel disaccharide side chain (Gal_4S6S-α1,2-L-Fuc_3S-α1,3), and the favorable sulfation pattern (Fuc_2S4S) serve as the molecular basis for potent P-selectin inhibition. This study provides a robust theoretical foundation for the structural optimization of glycomimetic targeting P-selectin, while also offering a new opportunity for the development of high-efficacy drug candidates. Full article

N-Glycolylneuraminic acid (Neu5Gc) is a non-human sialic acid present in mammalian tissues and certain dairy products. Although humans cannot synthesize Neu5Gc, it can be metabolically incorporated from dietary sources, potentially leading to the generation of anti-Neu5Gc antibodies, and has been associated with chronic inflammatory responses. While Neu5Gc distribution has been extensively studied in red meat, its presence in processed dairy products remains insufficiently characterized. In this pilot study, nano ultra-high-performance liquid chromatography coupled with electrospray ionization–tandem mass spectrometry (nano-UHPLC–ESI–MS/MS) was used for qualitative characterization of Neu5Gc-containing N-glycans in two commercially available cheese products. Neu5Gc-positive N-glycans were identified in reduced-fat sharp cheddar cheese (CHE), whereas such structures were not observed in processed cheddar cheese slices (SLI). These findings suggest that dairy processing and formulation parameters may influence glycan composition and Neu5Gc identification in cheddar cheese. Further studies using quantitative approaches and a broader range of dairy matrices are warranted to elucidate how processing-related factors affect Neu5Gc availability and its potential implications for diet-associated inflammation. Full article

The rumen microbiota plays a key role in nutrient fermentation and short-chain fatty acid (SCFA) production in ruminants. However, the impacts of different feeding regimes on rumen microbial composition, functional potential, and metabolic outputs remain unclear. In this study, rumen fluid samples were collected from 12 Longdong goats (Capra hircus), which were divided into four groups based on feeding regime and coat color: housed white goats (n = 3), housed black goats (n = 3), grazing white goats (n = 3), and grazing black goats (n = 3). Samples were analyzed using high-throughput sequencing combined with functional annotation (KEGG and CAZy) and targeted SCFA profiling. Distinct differences in microbial community composition were observed primarily between feeding regimes, with enrichment of taxa related to carbohydrate degradation and fermentation. Functional analyses revealed significant shifts in metabolic pathways, particularly those associated with carbohydrate metabolism, energy production, and glycan biosynthesis. Several glycoside hydrolase and glycosyltransferase families showed differential abundances across groups. Consistently, SCFA concentrations varied significantly among feeding regimes. Correlation analyses further demonstrated strong associations between key microbial taxa, functional pathways, and specific SCFAs. Overall, these results indicate that feeding regime, rather than coat color, plays a dominant role in shaping rumen microbial structure, functional capacity, and fermentation characteristics, providing insights into microbial mechanisms underlying rumen metabolism and informing feeding strategy optimization. Full article

Background: Tumour glycosylation regulates immune modulation and progression, but whether the CRC sialylome—the complete repertoire of sialylated glycans—defines a biologically distinct subtype remains unclear. We investigated how the “sugar code” shapes CRC biology, immunity, and therapeutic response. Methods: Transcriptomic data from three CRC cohorts (TCGA, Sidra-LUMC, and CPTAC-2; n = 988) were batch-corrected and integrated. Single-sample gene set enrichment analysis (ssGSEA) quantified sialyltransferase expression, sialic acid metabolism, EMT, MDR mechanisms, immune phenotypes, and Siglec-associated transcriptional signatures. GSEA, gene ontology enrichment analysis (GOEA), and drug ontology enrichment analysis (DOEA) characterised pathways and identified drug response-associated transcriptional signatures. Results: High sialylome activity defined a genomically stable but clinically advanced CRC subset enriched for left-sided tumours, mucinous histology, MSI, and BRAF mutations. At the transcriptional level, Sialyl-High tumours were associated with a mesenchymal, stromal-remodelling programme accompanied by reduced proliferative activity. They demonstrated enrichment of vesicular trafficking-related pathways alongside reduced representation of canonical efflux-associated programmes. Critically, the sialylome was associated with Siglec-related immune signatures, with sialylated glycan-related gene expression correlating with Siglec receptor expression (CD33 and SIGLEC7/9/10), consistent with an immune-inflamed yet structurally excluded microenvironment. DOEA identified selective enrichment of drug-response signatures related to sialic acid metabolism inhibitors (oseltamivir and Neu5Ac) and glycocalyx-disrupting agents (ginsenosides and soyasaponins). Conclusions: The CRC sialylome is associated with tumour phenotypic variation, including immune-excluded states linked to Siglec-associated transcriptional signatures and patterns consistent with non-canonical drug resistance programmes. These findings position the “sugar code” as a central organising principle in CRC and identify glycan-directed therapies as a promising strategy for the targeting of this aggressive subtype. Full article

The gut microbiota takes charge in a pivotal role in metabolic equilibrium, immune response, and modulating gut lining stability and has become the main focus of nutrition and functional food research. In this regard, the definition of prebiotics has progressed past the traditional approach limited to indigestible dietary fibers, embracing more targeted, biologically active, and functional delivery systems. In recent years, plant-derived exosomes (PDEs), a subclass of exosomes defined as extracellular vesicles (EVs) in the 30–150 nm size range, have emerged as an innovative class of nanostructures supporting this transformation. Plant-derived exosome-like nanoparticles (PELNs) have been taken into account as natural nanocarriers which are suitable for the gastrointestinal system with the help of their high biocompatibility, low immunogenicity profiles and rich bioactive cargo contents. This review discusses structural features of PELNs, molecular cargo content, and biological roles comprehensively and focuses especially on gut microbiota interactions. MicroRNAs, proteins, lipids, polyphenols, and glycans which PELNs contain are discussed with regard to shaping the microbial composition, regulating microbial metabolic activity, and modulating host-microbe communication. Findings derived from in vitro, in vivo, and limited translational studies indicate that PELNs can modulate specific microbial taxa, increase short-chain fatty acid (SCFA) yield, strengthen mucosal immune homeostasis, and induce source-dependent responses in the gut microbiota. In their traditional definition, prebiotics are taken into account as food components which selectively support proliferation and metabolism of helpful microbes, especially Bifidobacteria and Lactobacilli. Within this framework, PELNs are not only passive carriers of functional components but also evaluated as active systems which can directly affect microbiota composition and metabolic functions. Thus, they are repositioned as “prebiotic nanocarriers.” Also this review evaluates the potential of functional food and integration of major edible PELNs into synbiotic formulations by discussing their isolation and characterization methods and stabilities in the gastrointestinal environment. Limitations of clinical applications and lack of research from a prebiotic nanocarrier perspective of PELNs show that this field still contains important research gaps. The novelty of the study lies in its integration of PELN research with nutrition-based approaches to microbiota modulation and innovative functional food strategies under a single multidisciplinary conceptual framework. Full article

Natural food-derived proteins are increasingly explored as alternatives to synthetic inhibitors for managing Type 2 diabetes mellitus. Despite the recognized health-promoting properties of Morchella esculenta, the potential of its bioactive proteins to modulate glucose metabolism remains largely unexplored. This study systematically investigated the structural basis and hypoglycemic mechanisms of MEP5 (Morchella esculenta Protein 5), a fucose-specific lectin from M. esculenta, using an integrated in silico pipeline. MEP5 (33.12 kDa) adopts a stable β-sheet-rich conformation and harbors a conserved fucose-binding carbohydrate-recognition domain. Protein–protein docking revealed that intact MEP5 binds directly to surface glycans of human α-glucosidase, generating steric hindrance that obstructs the catalytic pocket. Simulated gastrointestinal digestion yielded a highly bioavailable peptide profile. Following a rigorous multiparametric screening for toxicity, allergenicity, and water solubility, 11 short oligopeptides were identified as potent dipeptidyl peptidase-IV (DPP-IV) inhibitors. Molecular docking demonstrated that the top-ranked peptides, QPPR, DGTY, and DPDSH, occupy the S2 pocket of DPP-IV and form hydrogen bonds with catalytic triad residues (Ser630/His740). These findings delineate a dual-stage hypoglycemic mechanism, pre-digestion enzymatic blockade and post-digestion incretin regulation, and support the potential of MEP5 as a multifunctional candidate for glucose homeostasis-oriented functional foods. Full article

Glycosylation is one of the most prevalent post-translational modifications of membrane proteins and plays a central role in regulating their structure and function. Unlike many existing reviews that address glycosylation in a system-wide context, this review focuses specifically on membrane proteins and examines how glycosylation shapes their functional behavior and clinical relevance. Because membrane proteins are exposed to the extracellular environment, glycans on their surface directly influence protein folding, receptor organization, and interactions with ligands and immune components. These diverse effects can be understood within a common mechanistic framework in which glycosylation modulates protein conformation, receptor clustering, and membrane organization, thereby altering signaling, adhesion, transport, and immune recognition. We discuss how N-linked and O-linked glycosylation regulate major classes of membrane proteins across these processes. Particular attention is given to disease-associated alterations in glycosylation, especially in cancer, immune and inflammatory disorders, and metabolic disease. For instance, glycosylation-dependent stabilization of PD-L1 and modulation of receptor signaling, such as EGFR, illustrate how glycan modifications contribute to immune evasion and therapeutic response. We further consider the clinical implications of membrane protein glycosylation, including its roles in biomarker development and as a potential target for therapeutic intervention. Advances in glycoproteomic technologies have enabled increasingly detailed characterization of site-specific glycosylation, although significant analytical challenges remain, particularly for membrane proteins. Overall, this review highlights membrane protein glycosylation as a dynamic regulatory layer that links molecular mechanisms to functional outcomes and clinical applications. Full article

Polysialic acid (PSA), a highly negatively charged glycan attached mainly to the neural cell adhesion molecule (NCAM), is emerging as a critical but underrecognized extracellular regulator of glutamatergic neurotransmission. While previous literature has focused on PSA’s developmental roles, increasing evidence indicates that PSA–NCAM also contributes to synaptic plasticity mechanisms in the mature brain. This review integrates evidence from structural biophysics, single-channel electrophysiology, and disease models to explain how PSA modulates glutamate receptor gating to control learning and memory. We synthesize findings from biochemical reconstitution, electrophysiological recordings, and in vivo studies to show that PSA can modulate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor open probability, burst duration, and cooperative gating without affecting conductance, thereby promoting long-term potentiation. Conversely, PSA selectively suppresses GluN2B-containing extrasynaptic N-methyl D-Aspartate (NMDA) receptor activity by lowering open probability and calcium influx, maintaining an optimal balance between potentiation and depression while providing neuroprotection. Disruption of PSA–NCAM signaling in developmental and disease models, including prenatal cannabinoid exposure and neurodegeneration, produces cognitive deficits reversible by PSA restoration. Notably, much of the current evidence derives from in vitro systems, with relatively few studies conducted in vivo, and studies employing PSA mimetics mostly, which should be considered when interpreting physiological relevance. Collectively, the available evidence suggests that PSA functions as an extracellular modulator linking synaptic glycans to glutamate receptor regulation and plasticity related signaling pathways, highlighting the potential importance of extracellular glycan mechanisms in the control of synaptic function. Full article

Seasonal human coronaviruses (HCoVs) continue to undergo adaptive evolution under structural and immune-mediated constraints. We investigated the molecular epidemiology and spike (S) protein structural variation of circulating coronaviruses in Riyadh, Saudi Arabia, during the 2025–2026 winter season, with particular emphasis on genotype persistence and glycosylation architecture in HCoV-OC43. Among 293 nasopharyngeal aspirates (NPAs) collected from hospitalized patients with acute respiratory illness, HCoV-OC43 was detected in 26 cases (8.87%), whereas other seasonal coronaviruses were not identified. Partial sequencing of the S gene revealed 97.84–98.23% nucleotide identity relative to the prototype strain VR-759, with amino acid substitutions distributed at discrete positions rather than within extended variable domains, indicating structural conservation. Phylogenetic reconstruction demonstrated that all Riyadh isolates clustered within genotype C, together with previously circulating local strains, supporting sustained endemic persistence and in situ evolution. In silico analysis of the S protein glycosylation landscape identified four invariant N-linked glycosylation motifs (N-X-S/T) at residues 46, 121, 134, and 190, reflecting strong structural constraints on glycan-dependent folding and antigenic configuration. A genotype-associated K68N substitution generated an additional N-glycosylation motif (68NGTD) in multiple Riyadh isolates, potentially modifying local glycan shielding without disrupting the overall glycosylation framework. The preservation of core glycosylation sites alongside selective motif acquisition suggests evolutionary fine-tuning of S surface topology rather than large-scale structural remodeling. Collectively, these findings indicate that genotype C persistence in Riyadh is accompanied by conserved S architecture and subtle glycosylation adjustments that may modulate immune recognition while maintaining structural integrity. Continued high-resolution molecular surveillance will be critical for defining the functional consequences of S microevolution in endemic HCoVs. Full article