A unique serum IgG glycosylation signature predicts development of Crohn's disease and is associated with pathogenic antibodies to mannose glycan.

Inflammatory bowel disease (IBD) is characterized by chronic inflammation in the gut. There is growing evidence in Crohn's disease (CD) of the existence of a preclinical period characterized by immunological changes preceding symptom onset that starts years before diagnosis. Gaining insight into this preclinical phase will allow disease prediction and prevention. Analysis of preclinical serum samples, up to 6 years before IBD diagnosis (from the PREDICTS cohort), revealed the identification of a unique glycosylation signature on circulating antibodies (IgGs) characterized by lower galactosylation levels of the IgG fragment crystallizable (Fc) domain that remained stable until disease diagnosis. This specific IgG2 Fc glycan trait correlated with increased levels of antimicrobial antibodies, specifically anti-Saccharomyces cerevisiae (ASCA), pinpointing a glycome-ASCA hub detected in serum that predates by years the development of CD. Mechanistically, we demonstrated that this agalactosylated glycoform of ASCA IgG, detected in the preclinical phase, elicits a proinflammatory immune pathway through the activation and reprogramming of innate immune cells, such as dendritic cells and natural killer cells, via an FcγR-dependent mechanism, triggering NF-κB and CARD9 signaling and leading to inflammasome activation. This proinflammatory role of ASCA was demonstrated to be dependent on mannose glycan recognition and galactosylation levels in the IgG Fc domain. The pathogenic properties of (anti-mannose) ASCA IgG were validated in vivo. Adoptive transfer of antibodies to mannan (ASCA) to recipient wild-type mice resulted in increased susceptibility to intestinal inflammation that was recovered in recipient FcγR-deficient mice. Here we identify a glycosylation signature in circulating IgGs that precedes CD onset and pinpoint a specific glycome-ASCA pathway as a central player in the initiation of inflammation many years before CD diagnosis. This pathogenic glyco-hub may constitute a promising new serum biomarker for CD prediction and a potential target for disease prevention.

Human gut microbes express functionally distinct endoglycosidases to metabolize the same N-glycan substrate.

Bacteroidales (syn. Bacteroidetes) are prominent members of the human gastrointestinal ecosystem mainly due to their efficient glycan-degrading machinery, organized into gene clusters known as polysaccharide utilization loci (PULs). A single PUL was reported for catabolism of high-mannose (HM) N-glycan glyco-polypeptides in the gut symbiont Bacteroides thetaiotaomicron, encoding a surface endo-ß-N-acetylglucosaminidase (ENGase), BT3987. Here, we discover an ENGase from the GH18 family in B. thetaiotaomicron, BT1285, encoded in a distinct PUL with its own repertoire of proteins for catabolism of the same HM N-glycan substrate as that of BT3987. We employ X-ray crystallography, electron microscopy, mass spectrometry-based activity measurements, alanine scanning mutagenesis and a broad range of biophysical methods to comprehensively define the molecular mechanism by which BT1285 recognizes and hydrolyzes HM N-glycans, revealing that the stabilities and activities of BT1285 and BT3987 were optimal in markedly different conditions. BT1285 exhibits significantly higher affinity and faster hydrolysis of poorly accessible HM N-glycans than does BT3987. We also find that two HM-processing endoglycosidases from the human gut-resident Alistipes finegoldii display condition-specific functional properties. Altogether, our data suggest that human gut microbes employ evolutionary strategies to express distinct ENGases in order to optimally metabolize the same N-glycan substrate in the gastroinstestinal tract.

Spatial N-glycomics of the normal breast microenvironment reveals fucosylated and high-mannose N-glycan signatures related to BI-RADS density and ancestry.

Higher breast cancer mortality rates continue to disproportionally affect black women (BW) compared to white women (WW). This disparity is largely due to differences in tumor aggressiveness that can be related to distinct ancestry-associated breast tumor microenvironments (TMEs). Yet, characterization of the normal microenvironment (NME) in breast tissue and how they associate with breast cancer risk factors remains unknown. N-glycans, a glucose metabolism-linked post-translational modification, has not been characterized in normal breast tissue. We hypothesized that normal female breast tissue with distinct Breast Imaging and Reporting Data Systems (BI-RADS) categories have unique microenvironments based on N-glycan signatures that varies with genetic ancestries. Profiles of N-glycans were characterized in normal breast tissue from BW (n = 20) and WW (n = 20) at risk for breast cancer using matrix assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI). A total of 176 N-glycans (32 core-fucosylated and 144 noncore-fucosylated) were identified in the NME. We found that certain core-fucosylated, outer-arm fucosylated and high-mannose N-glycan structures had specific intensity patterns and histological distributions in the breast NME dependent on BI-RADS densities and ancestry. Normal breast tissue from BW, and not WW, with heterogeneously dense breast densities followed high-mannose patterns as seen in invasive ductal and lobular carcinomas. Lastly, lifestyles factors (e.g. age, menopausal status, Gail score, BMI, BI-RADS) differentially associated with fucosylated and high-mannose N-glycans based on ancestry. This study aims to decipher the molecular signatures in the breast NME from distinct ancestries towards improving the overall disparities in breast cancer burden.

Global View of Domain-Specific O-Linked Mannose Glycosylation in Glycoengineered Cells.

Protein O-linked mannose (O-Man) glycosylation is an evolutionary conserved posttranslational modification that fulfills important biological roles during embryonic development. Three nonredundant enzyme families, POMT1/POMT2, TMTC1-4, and TMEM260, selectively coordinate the initiation of protein O-Man glycosylation on distinct classes of transmembrane proteins, including α-dystroglycan, cadherins, and plexin receptors. However, a systematic investigation of their substrate specificities is lacking, in part due to the ubiquitous expression of O-Man glycosyltransferases in cells, which precludes analysis of pathway-specific O-Man glycosylation on a proteome-wide scale. Here, we apply a targeted workflow for membrane glycoproteomics across five human cell lines to extensively map O-Man substrates and genetically deconstruct O-Man initiation by individual and combinatorial knockout of O-Man glycosyltransferase genes. We established a human cell library for the analysis of substrate specificities of individual O-Man initiation pathways by quantitative glycoproteomics. Our results identify 180 O-Man glycoproteins, demonstrate new protein targets for the POMT1/POMT2 pathway, and show that TMTC1-4 and TMEM260 pathways widely target distinct Ig-like protein domains of plasma membrane proteins involved in cell-cell and cell-extracellular matrix interactions. The identification of O-Man on Ig-like folds adds further knowledge on the emerging concept of domain-specific O-Man glycosylation which opens for functional studies of O-Man-glycosylated adhesion molecules and receptors.

Biochemical identification of D-mannose 2-epimerase from Cytophagaceae bacterium SJW1-29 for efficient bioconversion of D-glucose to D-mannose.

Enzymatic production of D-mannose attracts increasing attention because of the health effects and commercial values of D-mannose. Several kinds of epimerases or isomerases have been used for enzymatic production of D-mannose from D-glucose or D-fructose. D-Mannose epimerase (MEase), belonging to N-acyl-D-glucosamine 2-epimerase superfamily enzymes, catalyzes the C-2 epimerization between D-glucose and D-mannose. In this study, a novel MEase was identified from Cytophagaceae bacterium SJW1-29. Sequence and structure alignments indicate that it is highly conserved with the reported R. slithyformis MEase with the known crystal structure. It was a metal-independent enzyme, with an optimal pH of 8.0 and an optimal temperature of 40 °C. The specific activities on D-glucose and D-mannose were 2.90 and 2.96 U/mg, respectively. The Km, kcat, and kcat/Km on D-glucose were measured to be 194.9 mM, 2.72 s-1, and 0.014 mM-1 s-1, respectively. The purified enzyme produced 23.15 g/L of D-mannose from 100 g/L of D-glucose at pH 8.0 and 40 °C for 8 h, with a conversion rate of 23.15 %.

Single-Cell Analyses Reveal the Metabolic Heterogeneity and Plasticity of the Tumor Microenvironment during Head and Neck Squamous Cell Carcinoma Progression.

Metabolic reprogramming is a hallmark of cancer. In addition to metabolic alterations in the tumor cells, multiple other metabolically active cell types in the tumor microenvironment (TME) contribute to the emergence of a tumor-specific metabolic milieu. Here, we defined the metabolic landscape of the TME during the progression of head and neck squamous cell carcinoma (HNSCC) by performing single-cell RNA sequencing on 26 human patient specimens, including normal tissue, precancerous lesions, early stage cancer, advanced-stage cancer, lymph node metastases, and recurrent tumors. The analysis revealed substantial heterogeneity at the transcriptional, developmental, metabolic, and functional levels in different cell types. SPP1+ macrophages were identified as a protumor and prometastatic macrophage subtype with high fructose and mannose metabolism, which was further substantiated by integrative analysis and validation experiments. An inhibitor of fructose metabolism reduced the proportion of SPP1+ macrophages, reshaped the immunosuppressive TME, and suppressed tumor growth. In conclusion, this work delineated the metabolic landscape of HNSCC at a single-cell resolution and identified fructose metabolism as a key metabolic feature of a protumor macrophage subpopulation. Significance: Fructose and mannose metabolism is a metabolic feature of a protumor and prometastasis macrophage subtype and can be targeted to reprogram macrophages and the microenvironment of head and neck squamous cell carcinoma.

Conserved cysteines prevent C-mannosylation of mucin Cys domains.

Mucins are major components of the mucus. Besides the highly O-glycosylated tandem repeat domains, mucins contain Cys domains (CysDs). CysDs contain conserved disulfide-forming cysteine residues as well as a WxxW motif. Since this is the consensus sequence for tryptophan C-mannosylation, mucin CysDs have been suggested to be targets for C-mannosyltransferases, but this has never been directly shown. Here, we recombinantly expressed human mucin CysDs in Chinese hamster ovary (CHO) cells and analyzed the C-mannosylation status. Mass spectrometric analysis revealed that the putative C-mannose site is not or only barely C-mannosylated. However, mutation of the adjacent cysteine residues enabled C-mannosylation to occur. In contrast to mucin CysDs, the homologous CysD of human cartilage intermediate layer protein 1 (CILP1) lacks these cysteine residues preceding the WxxW motif. We show that CILP1 CysD is C-mannosylated, but introducing a cysteine at the -2 position causes this modification to be lost. We thus conclude that the presence of cysteine residues prevents the modification of the WxxW motif in CysDs.

High-mannose glycans from Schistosoma mansoni eggs are important for priming of Th2 responses via Dectin-2 and prostaglandin E2.

The parasitic helminth Schistosoma mansoni is a potent inducer of type 2 immune responses by stimulating dendritic cells (DCs) to prime T helper 2 (Th2) responses. We previously found that S. mansoni soluble egg antigens (SEA) promote the synthesis of Prostaglandin E2 (PGE2) by DCs through ERK-dependent signaling via Dectin-1 and Dectin-2 that subsequently induces OX40L expression, licensing them for Th2 priming, yet the ligands present in SEA involved in driving this response and whether specific targeting of PGE2 synthesis by DCs could affect Th2 polarization are unknown. We here show that the ability of SEA to bind Dectin-2 and drive ERK phosphorylation, PGE2 synthesis, OX40L expression, and Th2 polarization is impaired upon cleavage of high-mannose glycans by Endoglycosidase H treatment. This identifies high-mannose glycans present on glycoproteins in SEA as important drivers of this signaling axis. Moreover, we find that OX40L expression and Th2 induction are abrogated when microsomal prostaglandin E synthase-1 (mPGES) is selectively inhibited, but not when a general COX-1/2 inhibitor is used. This shows that the de novo synthesis of PGE2 is vital for the Th2 priming function of SEA-stimulated DCs as well as points to the potential existence of other COX-dependent lipid mediators that antagonize PGE2-driven Th2 polarization. Lastly, specific PGE2 inhibition following immunization with S. mansoni eggs dampened the egg-specific Th cell response. In summary, our findings provide new insights in the molecular mechanisms underpinning Th2 induction by S. mansoni and identify druggable targets for potential control of helminth driven-Th2 responses.

Liposome-encapsulated mannose-1-phosphate therapy improves global N-glycosylation in different congenital disorders of glycosylation.

Phosphomannomutase 2 (PMM2) converts mannose-6-phospahate to mannose-1-phosphate; the substrate for GDP-mannose, a building block of the glycosylation biosynthetic pathway. Pathogenic variants in the PMM2 gene have been shown to be associated with protein hypoglycosylation causing PMM2-congenital disorder of glycosylation (PMM2-CDG). While mannose supplementation improves glycosylation in vitro, but not in vivo, we hypothesized that liposomal delivery of mannose-1-phosphate could increase the stability and delivery of the activated sugar to enter the targeted compartments of cells. Thus, we studied the effect of liposome-encapsulated mannose-1-P (GLM101) on global protein glycosylation and on the cellular proteome in skin fibroblasts from individuals with PMM2-CDG, as well as in individuals with two N-glycosylation defects early in the pathway, namely ALG2-CDG and ALG11-CDG. We leveraged multiplexed proteomics and N-glycoproteomics in fibroblasts derived from different individuals with various pathogenic variants in PMM2, ALG2 and ALG11 genes. Proteomics data revealed a moderate but significant change in the abundance of some of the proteins in all CDG fibroblasts upon GLM101 treatment. On the other hand, N-glycoproteomics revealed the GLM101 treatment enhanced the expression levels of several high-mannose and complex/hybrid glycopeptides from numerous cellular proteins in individuals with defects in PMM2 and ALG2 genes. Both PMM2-CDG and ALG2-CDG exhibited several-fold increase in glycopeptides bearing Man6 and higher glycans and a decrease in Man5 and smaller glycan moieties, suggesting that GLM101 helps in the formation of mature glycoforms. These changes in protein glycosylation were observed in all individuals irrespective of their genetic variants. ALG11-CDG fibroblasts also showed increase in high mannose glycopeptides upon treatment; however, the improvement was not as dramatic as the other two CDG. Overall, our findings suggest that treatment with GLM101 overcomes the genetic block in the glycosylation pathway and can be used as a potential therapy for CDG with enzymatic defects in early steps in protein N-glycosylation.

Thermodynamics-Guided Design Reveals a Cooperative Hydrogen Bond in DC-SIGN-targeted Glycomimetics.

Due to the shallow and hydrophilic binding sites of carbohydrate-binding proteins, the design of glycomimetics is often complicated by high desolvation costs as well as competition with solvent. Therefore, a careful optimization of interaction vectors and ligand properties is required in the design and optimization of glycomimetics. Here, we employ thermodynamics-guided design to optimize mannose-based glycomimetics targeting the human C-type lectin receptor dendritic cell-specific intercellular adhesion molecule 3 grabbing nonintegrin (DC-SIGN), a pathogenic host factor in viral infections. By exploring ligand rigidification and hydrogen bond engineering, a monovalent glycomimetic with an unprecedented affinity for DC-SIGN in the low µM range was discovered. A matched molecular pair analysis based on microcalorimetric data revealed a stereospecific hydrogen bond interaction with Glu358/Ser360 as the origin of this cooperative and enthalpically dominated interaction. This detailed insight into the binding mechanism paves the way for an improvement of monovalent glycomimetics targeting DC-SIGN.

D-mannose as a new therapy for fucokinase deficiency-related congenital disorder of glycosylation (FCSK-CDG).

INTRODUCTION: Fucokinase deficiency-related congenital disorder of glycosylation (FCSK-CDG) is a rare autosomal recessive inborn error of metabolism characterized by a decreased flux through the salvage pathway of GDP-fucose biosynthesis due to a block in the recycling of L-fucose that exits the lysosome. FCSK-CDG has been described in 5 individuals to date in the medical literature, with a phenotype comprising global developmental delays/intellectual disability, hypotonia, abnormal myelination, posterior ocular disease, growth and feeding failure, immune deficiency, and chronic diarrhea, without clear therapeutic recommendations. PATIENT AND METHODS: In a so far unreported FCSK-CDG patient, we studied proteomics and glycoproteomics in vitro in patient-derived fibroblasts and also performed in vivo glycomics, before and after treatment with either D-Mannose or L-Fucose. RESULTS: We observed a marked increase in fucosylation after D-mannose supplementation in fibroblasts compared to treatment with L-Fucose. The patient was then treated with D-mannose at 850 mg/kg/d, with resolution of the chronic diarrhea, resolution of oral aversion, improved weight gain, and observed developmental gains. Serum N-glycan profiles showed an improvement in the abundance of fucosylated glycans after treatment. No treatment-attributed adverse effects were observed. CONCLUSION: D-mannose is a promising new treatment for FCSK-CDG.

Mannose controls mesoderm specification and symmetry breaking in mouse gastruloids.

Patterning and growth are fundamental features of embryonic development that must be tightly coordinated. To understand how metabolism impacts early mesoderm development, we used mouse embryonic stem-cell-derived gastruloids, that co-expressed glucose transporters with the mesodermal marker T/Bra. We found that the glucose mimic, 2-deoxy-D-glucose (2-DG), blocked T/Bra expression and abolished axial elongation in gastruloids. However, glucose removal did not phenocopy 2-DG treatment despite a decline in glycolytic intermediates. As 2-DG can also act as a competitive inhibitor of mannose in protein glycosylation, we added mannose together with 2-DG and found that it could rescue the mesoderm specification both in vivo and in vitro. We further showed that blocking production and intracellular recycling of mannose abrogated mesoderm specification. Proteomics analysis demonstrated that mannose reversed glycosylation of the Wnt pathway regulator, secreted frizzled receptor Frzb. Our study showed how mannose controls mesoderm specification in mouse gastruloids.

Biochemical changes in lipid and protein metabolism caused by mannose-Raman spectroscopy studies.

Biochemical analysis of human normal bronchial cells (BEpiC) and human cancer lung cells (A549) has been performed by using Raman spectroscopy and Raman imaging. Our approach provides a biochemical compositional mapping of the main cell components: nucleus, mitochondria, lipid droplets, endoplasmic reticulum, cytoplasm and cell membrane. We proved that Raman spectroscopy and Raman imaging can distinguish successfully BEpiC and A549 cells. In this study, we have focused on the role of mannose in cancer development. It has been shown that changes in the concentration of mannose can regulate some metabolic processes in cells. Presented results suggest lipids and proteins can be considered as Raman biomarkers during lung cancer progression. Analysis obtained for bands 1444 cm-1, and 2854 cm-1 characteristic for lipids and derivatives proved that the addition of mannose reduced levels of these compounds. Results obtained for protein compounds based on bands 858 cm-1, 1004 cm-1 and 1584 cm-1 proved that the addition of mannose increases the values of protein in BEpiC cells and blocks protein glycolisation in A549 cells. Noticing Raman spectral changes in BEpiC and A549 cells supplemented with mannose can help to understand the mechanism of sugar metabolism during cancer development and could play in the future an important role in clinical treatment.

Integrating network pharmacology and experimental validation reveals therapeutic effects of D-mannose on NAFLD through mTOR suppression.

Non-alcoholic fatty liver disease (NAFLD), a chronic liver condition and metabolic disorder, has emerged as a significant health issue worldwide. D-mannose, a natural monosaccharide widely existing in plants and animals, has demonstrated metabolic regulatory properties. However, the effect and mechanism by which D-mannose may counteract NAFLD have not been studied. In this study, network pharmacology followed by molecular docking analysis was utilized to identify potential targets of mannose against NAFLD, and the leptin receptor-deficient, genetically obese db/db mice was employed as an animal model of NAFLD to validate the regulation of D-mannose on core targets. As a result, 67 targets of mannose are predicted associated with NAFLD, which are surprisingly centered on the mechanistic target of rapamycin (mTOR). Further analyses suggest that mTOR signaling is functionally enriched in potential targets of mannose treating NAFLD, and that mannose putatively binds to mTOR as a core mechanism. Expectedly, repeated oral gavage of supraphysiological D-mannose ameliorates liver steatosis of db/db mice, which is based on suppression of hepatic mTOR signaling. Moreover, daily D-mannose administration reduced hepatic expression of lipogenic regulatory genes in counteracting NAFLD. Together, these findings reveal D-mannose as an effective and potential NAFLD therapeutic through mTOR suppression, which holds translational promise.

It takes two to attach - endo-1,3-ß-d-glucanase as a potential receptor of mannose-independent, FimH-dependent Salmonella Typhimurium binding to spinach leaves.

Currently, fresh, unprocessed food has become a relevant element of the chain of transmission of enteropathogenic infections. To survive on a plant surface and further spread the infections, pathogens like Salmonella have to attach stably to the leaf surface. Adhesion, driven by various virulence factors, including the most abundant fim operon encoding type 1 fimbriae, is usually an initial step of infection, preventing physical removal of the pathogen. Adhesion properties of Salmonella's type 1 fimbriae and its FimH adhesin were investigated intensively in the past. However, there is a lack of knowledge regarding its role in interaction with plant cells. Understanding the mechanisms and structures involved in such interaction may facilitate efforts to decrease the risk of contamination and increase fresh food safety. Here, we applied Salmonella genome site-directed mutagenesis, adhesion assays, protein-protein interactions, and biophysics methods based on surface plasmon resonance to unravel the role of FimH adhesin in interaction with spinach leaves. We show that FimH is at least partially responsible for Salmonella binding to spinach leaves, and this interaction occurs in a mannose-independent manner. Importantly, we identified a potential FimH receptor as endo-1,3-ß-d-Glucanase and found that this interaction is strong and specific, with a dissociation constant in the nanomolar range. This research advances our comprehension of Salmonella's interactions with plant surfaces, offering insights that can aid in minimizing contamination risks and improving the safety of fresh, unprocessed foods.

Biosynthesis of mannose from glucose via constructing phosphorylation-dephosphorylation reactions in Escherichia coli.

d-mannose has been widely used in food, medicine, cosmetic, and food-additive industries. To date, chemical synthesis or enzymatic conversion approaches based on iso/epimerization reactions for d-mannose production suffered from low conversion rate due to the reaction equilibrium, necessitating intricate separation processes for obtaining pure products on an industrial scale. To circumvent this challenge, this study showcased a new approach for d-mannose synthesis from glucose through constructing a phosphorylation-dephosphorylation pathway in an engineered strain. Specifically, the gene encoding phosphofructokinase (PfkA) in glycolytic pathway was deleted in Escherichia coli to accumulate fructose-6-phosphate (F6P). Additionally, one endogenous phosphatase, YniC, with high specificity to mannose-6-phosphate, was identified. In ΔpfkA strain, a recombinant synthetic pathway based on mannose-6-phosphate isomerase and YniC was developed to direct F6P to mannose. The resulting strain successfully produced 25.2 g/L mannose from glucose with a high conversion rate of 63% after transformation for 48 h. This performance surpassed the 15% conversion rate observed with 2-epimerases. In conclusion, this study presents an efficient method for achieving high-yield mannose synthesis from cost-effective glucose.

PMI-controlled mannose metabolism and glycosylation determines tissue tolerance and virus fitness.

Host survival depends on the elimination of virus and mitigation of tissue damage. Herein, we report the modulation of D-mannose flux rewires the virus-triggered immunometabolic response cascade and reduces tissue damage. Safe and inexpensive D-mannose can compete with glucose for the same transporter and hexokinase. Such competitions suppress glycolysis, reduce mitochondrial reactive-oxygen-species and succinate-mediated hypoxia-inducible factor-1α, and thus reduce virus-induced proinflammatory cytokine production. The combinatorial treatment by D-mannose and antiviral monotherapy exhibits in vivo synergy despite delayed antiviral treatment in mouse model of virus infections. Phosphomannose isomerase (PMI) knockout cells are viable, whereas addition of D-mannose to the PMI knockout cells blocks cell proliferation, indicating that PMI activity determines the beneficial effect of D-mannose. PMI inhibition suppress a panel of virus replication via affecting host and viral surface protein glycosylation. However, D-mannose does not suppress PMI activity or virus fitness. Taken together, PMI-centered therapeutic strategy clears virus infection while D-mannose treatment reprograms glycolysis for control of collateral damage.

The regulation of Cytochrome f by mannose treatment in broccoli and its relationship with programmed cell death in tobacco BY-2 cells.

It is well established that programmed cell death (PCD) occurred in broccoli during postharvest senescence, but no studies have been conducted on the regulation of broccoli cytochrome f by mannose treatment and its relationship with PCD. In this study, we treated broccoli buds with mannose to investigate the changes in color, total chlorophyll content, gene expression related to chlorophyll metabolism, chloroplast structure, and cytochrome f determination during postharvest storage. In addition, to investigate the effect of cytochrome f on PCD, we extracted cytochrome f from broccoli and treated Nicotiana tabacum L. cv Bright Yellow 2 (BY-2) cells with extracted cytochrome f from broccoli at various concentrations. The results showed that cytochrome f can induce PCD in tobacco BY-2 cells, as evidenced by altered cell morphology, nuclear chromatin disintegration, DNA degradation, decreased cell viability, and increased caspase-3-like protease production. Taken together, our study indicated that mannose could effectively delay senescence of postharvest broccoli by inhibiting the expression of gene encoding cytochrome f which could induce PCD.

Comparative study of 1H-NMR metabolomic profile of canine synovial fluid in patients affected by four progressive stages of spontaneous osteoarthritis.

The study aimed to assess the metabolomic profile of the synovial fluid (SF) of dogs affected by spontaneous osteoarthritis (OA) and compare any differences based on disease progression. Sixty client-owned dogs affected by spontaneous OA underwent clinical, radiographic, and cytologic evaluations to confirm the diagnosis. The affected joints were divided into four study groups based on the Kallgreen-Lawrence classification: OA1 (mild), OA2 (moderate), OA3 (severe), and OA4 (extremely severe/deforming). The osteoarthritic joint's SF was subjected to cytologic examination and 1H-NMR analysis. The metabolomic profiles of the study groups' SF samples were statistically compared using one-way ANOVA. Sixty osteoarthritic joints (45 stifles, 10 shoulders and 5 elbows) were included in the study. Fourteen, 28, and 18 joints were included in the OA1, OA2, and OA3 groups, respectively (0 joints in the OA4 group). Metabolomic analysis identified 48 metabolites, five of which were significantly different between study groups: Mannose and betaine were elevated in the OA1 group compared with the OA2 group, and the 2-hydroxyisobutyrate concentration decreased with OA progression; in contrast, isoleucine was less concentrated in mild vs. moderate OA, and lactate increased in severe OA. This study identified different 1H-NMR metabolomic profiles of canine SF in patients with progressive degrees of spontaneous OA, suggesting 1H-NMR metabolomic analysis as a potential alternative method for monitoring OA progression. In addition, the results suggest the therapeutic potentials of the metabolomic pathways that involve mannose, betaine, 2-hydroxyisobutyrate, isoleucine, and lactate.

Mannose Ligands for Mannose Receptor Targeting.

The mannose receptor (MR, CD 206) is an endocytic receptor primarily expressed by macrophages and dendritic cells, which plays a critical role in both endocytosis and antigen processing and presentation. MR carbohydrate recognition domains (CRDs) exhibit a high binding affinity for branched and linear oligosaccharides. Furthermore, multivalent mannose presentation on the various templates like peptides, proteins, polymers, micelles, and dendrimers was proven to be a valuable approach for the selective and efficient delivery of various therapeutically active agents to MR. This review provides a detailed account of the most relevant and recent aspects of the synthesis and application of mannosylated bioactive formulations for MR-mediated delivery in treatments of cancer and other infectious diseases. It further highlights recent findings related to the necessary structural features of the mannose-containing ligands for successful binding to the MR.