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Biochemistry May 2024Cyanovirin-N (CV-N) binds high-mannose oligosaccharides on enveloped viruses with two carbohydrate-binding sites, one bearing high affinity and one low affinity to...
Cyanovirin-N (CV-N) binds high-mannose oligosaccharides on enveloped viruses with two carbohydrate-binding sites, one bearing high affinity and one low affinity to Manα(1-2)Man moieties. A tandem repeat of two CV-N molecules (CVN2) was tested for antiviral activity against human immunodeficiency virus type I (HIV-1) by using a domain-swapped dimer. CV-N was shown to bind -acetylmannosamine (ManNAc) and -acetyl-d-glucosamine (GlcNAc) when the carbohydrate-binding sites in CV-N were free to interact with these monosaccharides independently. CVN2 recognized ManNAc at a of 1.4 μM and bound this sugar in solution, regardless of the lectin making amino acid side chain contacts on the targeted viral glycoproteins. An interdomain cross-contacting residue Glu41, which has been shown to be hydrogen bonding with dimannose, was substituted in the monomeric CV-N. The amide derivative of glucose, GlcNAc, achieved similar high affinity to the new variant CVN-E41T as high-mannose -glycans, but binding to CVN2 in the nanomolar range with four binding sites involved or binding to the monomeric CVN-E41A. A stable dimer was engineered and expressed from the alanine-to-threonine-substituted monomer to confirm binding to GlcNAc. In summary, low-affinity binding was achieved by CVN2 to dimannosylated peptide or GlcNAc with two carbohydrate-binding sites of differing affinities, mimicking biological interactions with the respective -linked glycans of interest and cross-linking of carbohydrates on human T cells for lymphocyte activation.
Topics: Acetylglucosamine; Binding Sites; Bacterial Proteins; Carrier Proteins; Humans; HIV-1; Protein Binding; Hexosamines; Models, Molecular; Protein Multimerization
PubMed: 38770609
DOI: 10.1021/acs.biochem.4c00113 -
Frontiers in Genetics 2024This report outlines the case of a child affected by a type of congenital disorder of glycosylation (CDG) known as ALG2-CDG (OMIM 607906), presenting as a congenital...
This report outlines the case of a child affected by a type of congenital disorder of glycosylation (CDG) known as ALG2-CDG (OMIM 607906), presenting as a congenital myasthenic syndrome (CMS) caused by variants identified in , which encodes an α1,3-mannosyltransferase (EC 2.4.1.132) involved in the early steps of N-glycosylation. To date, fourteen cases of ALG2-CDG have been documented worldwide. From birth, the child experienced perinatal asphyxia, muscular weakness, feeding difficulties linked to an absence of the sucking reflex, congenital hip dislocation, and hypotonia. Over time, additional complications emerged, such as inspiratory stridor, gastroesophageal reflux, low intake, recurrent seizures, respiratory infections, an inability to maintain the head upright, and a global developmental delay. Whole genome sequencing (WGS) revealed the presence of two variants in compound heterozygosity: a novel variant c.1055_1056delinsTGA p.(Ser352Leufs*3) and a variant of uncertain significance (VUS) c.964C>A p.(Pro322Thr). Additional studies, including determination of carbohydrate-deficient transferrin (CDT) revealed a mild type I CDG pattern and the presence of an abnormal transferrin glycoform containing a linear heptasaccharide consisting of one sialic acid, one galactose, one N-acetyl-glucosamine, two mannoses and two N-acetylglucosamines (NeuAc-Gal-GlcNAc-Man2-GlcNAc2), ALG2-CDG diagnostic biomarker, confirming the pathogenicity of these variants.
PubMed: 38770420
DOI: 10.3389/fgene.2024.1363558 -
World Journal of Gastrointestinal... May 2024Limited knowledge exists regarding the casual associations linking blood metabolites and the risk of developing colorectal cancer.
BACKGROUND
Limited knowledge exists regarding the casual associations linking blood metabolites and the risk of developing colorectal cancer.
AIM
To investigate causal associations between blood metabolites and colon cancer.
METHODS
The study utilized a two-sample Mendelian randomization (MR) analysis to investigate the causal impact of 486 blood metabolites on colorectal cancer. The primary method of analysis used was the inverse variance weighted model. To further validate the results several sensitivity analyses were performed, including Cochran's Q test, MR-Egger intercept test, and MR robust adjusted profile score. These additional analyses were conducted to ensure the reliability and robustness of the findings.
RESULTS
After rigorous selection for genetic variation, 486 blood metabolites were included in the MR analysis. We found Mannose [odds ratio (OR) = 2.09 (1.10-3.97), = 0.024], N-acetylglycine [OR = 3.14 (1.78-5.53), = 7.54 × 10], X-11593-O-methylascorbate [OR = 1.68 (1.04-2.72), = 0.034], 1-arachidonoylglycerophosphocholine [OR = 4.23 (2.51-7.12), = 6.35 × 10] and 1-arachidonoylglycerophosphoethanolamine 4 [OR = 3.99 (1.17-13.54), = 0.027] were positively causally associated with colorectal cancer, and we also found a negative causal relationship between Tyrosine [OR = 0.08 (0.01-0.63), = 0.014], Urate [OR = 0.25 (0.10-0.62), = 0.003], N-acetylglycine [0.73 (0.54-0.98), = 0.033], X-12092 [OR = 0.89 (0.81-0.99), = 0.028], Succinylcarnitine [OR = 0.48 (0.27-0.84), = 0.09] with colorectal cancer. A series of sensitivity analyses were performed to confirm the rigidity of the results.
CONCLUSION
This study showed a causal relationship between 10 blood metabolites and colorectal cancer, of which 5 blood metabolites were found to be causal for the development of colorectal cancer and were confirmed as risk factors. The other five blood metabolites are protective factors.
PubMed: 38764807
DOI: 10.4251/wjgo.v16.i5.1995 -
The Journal of Biological Chemistry May 2024The stepwise addition of monosaccharides to N-glycans attached to client proteins to generate a repertoire of mature proteins involves a concerted action of many...
The stepwise addition of monosaccharides to N-glycans attached to client proteins to generate a repertoire of mature proteins involves a concerted action of many glycosidases and glycosyltransferases. Here, we report that Golgi α-mannosidase II (GMII), a pivotal enzyme catalyzing the first step in the conversion of hybrid- to complex-type N-glycans, is activated by Zn supplied by the early secretory compartment-resident ZNT5-ZNT6 heterodimers (ZNT5-6) and ZNT7 homodimers (ZNT7). Loss of ZNT5-6 and ZNT7 function results in marked accumulation of hybrid-type and complex/hybrid glycans with concomitant reduction of complex- and high-mannose-type glycans. In cells lacking the ZNT5-6 and ZNT7 functions, the GMII activity is substantially decreased. In contrast, the activity of its homolog, lysosomal mannosidase (LAMAN), is not decreased. Moreover, we show that the growth of pancreatic cancer MIA PaCa-2 cells lacking ZNT5-6 and ZNT7 is significantly decreased in a nude mouse xenograft model. Our results indicate the integral roles of ZNT5-6 and ZNT7 in N-glycosylation and highlight their potential as novel target proteins for cancer therapy.
PubMed: 38762179
DOI: 10.1016/j.jbc.2024.107378 -
Fitoterapia Jul 2024Euphorbia himalayensis Boiss. is an alpine member of the Euphorbiaceae family. Its dried roots have been used to treat digestive problems and chest congestion in...
Euphorbia himalayensis Boiss. is an alpine member of the Euphorbiaceae family. Its dried roots have been used to treat digestive problems and chest congestion in traditional Tibetan and Mongolian medicine. Despite thousands of years of use in medicine, the bioactive compounds of the root remain unknown. Herein, we isolated a novel aqueous-soluble polysaccharide (EHP2) from the E. himalayensis root and determined its structural characteristics via high-performance gel permeation chromatography, Fourier-transform infrared spectroscopy, gas chromatography-mass spectrometry, and nuclear magnetic resonance spectrometry. The homogeneous molecular weight of EHP2 was 23.6 kDa with narrow polydisperity (Mw/Mn = 1.4), and EHP2 mainly comprised of glucose (86.4%), galactose (11.9%) and mannose (1.7%). The major backbone of EHP2 was →4)-α-D-GalAp-(1 → 4)-α-D-Glcp-(1 → and the branch chain was α-D-Glcp-(1→. The antioxidant activity of the EHP2 was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion radical scavenging assays, and antioxidant enzyme activity (SOD, GSH and MDA) was determined in human umbilical vein endothelial cells (HUVECs). The EHP2 demonstrated lower potential scavenging effects on DPPH and superoxide free radical scavenger than ascorbic acid, and in HUVECs, it led to increased SOD and GSH activities and decreased MDA levels. This study is the first to describe an E. himalayensis polysaccharide compound with potential antioxidant activity.
Topics: Euphorbia; Antioxidants; Polysaccharides; Plant Roots; Humans; Human Umbilical Vein Endothelial Cells; Molecular Structure; Phytochemicals
PubMed: 38759735
DOI: 10.1016/j.fitote.2024.106009 -
RMD Open May 2024To investigate lectin pathway proteins (LPPs) as biomarkers for axial spondyloarthritis (axSpA) in a cross-sectional cohort with a suspicion of axSpA, comprising newly...
OBJECTIVES
To investigate lectin pathway proteins (LPPs) as biomarkers for axial spondyloarthritis (axSpA) in a cross-sectional cohort with a suspicion of axSpA, comprising newly diagnosed axSpA and chronic low back pain (cLBP) individuals.
METHODS
Serum samples from 515 participants within the OptiRef cohort, including 151 axSpA patients and 364 cLBP patients, were measured using immunoassays for LPPs (mannan-binding lectin (MBL), collectin liver-1 (CL-L1), M-ficolin, H-ficolin and L-ficolin, MBL-associated serine proteases (MASP)-1, -2 and -3, MBL-associated proteins (MAp19 and MAp44) and the complement activation product C3dg).
RESULTS
Serum levels of L-ficolin, MASP-2 and C3dg were elevated in axSpA patients, whereas levels of MASP-3 and CL-L1 were decreased, and this remained significant for C3dg and MASP-3 after adjustment for C reactive protein (CRP). A univariate regression analysis showed serum levels of CL-L1, MASP-2, MASP-3 and C3dg to predict the diagnosis of axSpA, and MASP-3 and C3dg remained significant in a multivariate logistic regression analysis. Assessment of the diagnostic potential showed that a combination of human leukocyte antigen B27 (HLA-B27) and measurements of L-ficolin, MASP-3 and C3dg increased the diagnostic specificity for axSpA, however, with a concomitant loss of sensitivity.
CONCLUSIONS
Serum levels of complement activation, that is, C3dg, and MASP-3 differed significantly between axSpA and cLBP patients after adjustment for CRP. Although combining HLA-B27 with measurements of L-ficolin, MASP-3 and C3dg increased the diagnostic specificity for axSpA, this seems unjustified due to the concomitant loss of sensitivity. However, both C3dg and MASP-3 were associated with axSpA diagnosis in multivariate logistic regression, suggesting an involvement of complement in the inflammatory processes and possibly pathogenesis in axSpA.
Topics: Humans; Biomarkers; Male; Female; Adult; Middle Aged; Cross-Sectional Studies; Complement System Proteins; Axial Spondyloarthritis; Mannose-Binding Protein-Associated Serine Proteases; Lectins; Complement Activation
PubMed: 38749532
DOI: 10.1136/rmdopen-2024-004127 -
Frontiers in Immunology 2024The parasitic helminth 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...
The parasitic helminth 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 soluble egg antigens (SEA) promote the synthesis of Prostaglandin E (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 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 eggs dampened the egg-specific Th cell response. In summary, our findings provide new insights in the molecular mechanisms underpinning Th2 induction by and identify druggable targets for potential control of helminth driven-Th2 responses.
Topics: Animals; Schistosoma mansoni; Dinoprostone; Th2 Cells; Lectins, C-Type; Mannose; Mice; Polysaccharides; Antigens, Helminth; Dendritic Cells; Schistosomiasis mansoni; Ovum; Mice, Inbred C57BL; OX40 Ligand
PubMed: 38742105
DOI: 10.3389/fimmu.2024.1372927 -
Biomedicine & Pharmacotherapy =... Jun 2024Targeted degradation of pathological proteins is a promising approach to enhance the effectiveness of therapeutic monoclonal antibodies (mAbs) in cancer therapy. In this...
Targeted degradation of pathological proteins is a promising approach to enhance the effectiveness of therapeutic monoclonal antibodies (mAbs) in cancer therapy. In this study, we demonstrate that this objective can be efficiently achieved by the grafting of mannose 6-phosphate analogues called AMFAs onto the therapeutic antibodies trastuzumab and cetuximab, both directed against membrane antigens. The grafting of AMFAs confers to these antibodies the novel property of being internalized via the mannose 6-phosphate receptor (M6PR) pathway. AMFA conjugation to these mAbs significantly increases their cellular uptake and leads to enhanced degradation of the target antigens in cancer cells. This results in a drastic inhibition of cancer cell proliferation compared to unconjugated mAbs, as demonstrated in various cancer cell lines, and an increased therapeutic efficacy in mouse and zebrafish xenografted models. These findings highlight the potential of this technology to improve therapeutic outcomes in cancer treatment.
Topics: Animals; Humans; Zebrafish; Lysosomes; Cell Line, Tumor; Membrane Proteins; Trastuzumab; Xenograft Model Antitumor Assays; Cetuximab; Mice; Protein Engineering; Cell Proliferation; Mice, Nude; Antibodies, Monoclonal; Antineoplastic Agents, Immunological; Female; Neoplasms
PubMed: 38739989
DOI: 10.1016/j.biopha.2024.116707 -
Bio-protocol May 2024The cation-independent mannose 6-phosphate receptors (CI-M6PR) bind newly synthesized mannose 6-phosphate (Man-6-P)-tagged enzymes in the Golgi and transport them to...
The cation-independent mannose 6-phosphate receptors (CI-M6PR) bind newly synthesized mannose 6-phosphate (Man-6-P)-tagged enzymes in the Golgi and transport them to late endosomes/lysosomes, providing them with degradative functions. Following the cargo delivery, empty receptors are recycled via early/recycling endosomes back to the trans-Golgi network (TGN) retrogradely in a dynein-dependent motion. One of the most widely used methods for studying the retrograde trafficking of CI-M6PR involves employing the CD8α-CI-M6PR chimera. This chimera, comprising a CD8 ectodomain fused with the cytoplasmic tail of the CI-M6PR receptor, allows for labeling at the plasma membrane, followed by trafficking only in a retrograde direction. Previous studies utilizing the CD8α-CI-M6PR chimera have focused mainly on colocalization studies with various endocytic markers under steady-state conditions. This protocol extends the application of the CD8α-CI-M6PR chimera to live cell imaging, followed by a quantitative analysis of its motion towards the Golgi. Additionally, we present an approach to quantify parameters such as speed and track lengths associated with the motility of CD8α-CI-M6PR endosomes using the Fiji plugin TrackMate. Key features • This assay is adapted from the methodology by Prof. Matthew Seaman for studying the retrograde trafficking of CI-M6PR by expressing CD8α-CI-M6PR chimera in HeLa cells. • The experiments include live-cell imaging of surface-labeled CD8α-CI-M6PR molecules, followed by a chase in cells. • Allows the monitoring of real-time motion of CD8α-CI-M6PR endosomes and facilitates calculation of kinetic parameters associated with endosome trajectories, e.g., speed and distance (run lengths).
PubMed: 38737505
DOI: 10.21769/BioProtoc.4979 -
Frontiers in Microbiology 2024The identification of microorganisms with excellent flocculants-producing capability and optimization of the fermentation process are necessary for the wide-scale...
The identification of microorganisms with excellent flocculants-producing capability and optimization of the fermentation process are necessary for the wide-scale application of bioflocculants. Therefore, we isolated and identified a highly efficient flocculation performance strain of GXUN74707 from the sludge. The optimal fermentation and flocculation conditions of strain GXUN74707 was in fermentation medium with glucose and urea as the carbon and nitrogen sources, respectively, at pH 7.0 for 36 h, which treatment of kaolin suspension with 0.5 mL of the fermentation broth resulted in a flocculation rate of 99.0%. The bioflocculant synthesized by strain GXUN74707 was found mainly in the supernatant of the fermentation broth. Chemical analysis revealed that the pure bioflocculant consisted of 79.70% carbohydrates and 14.38% proteins. The monosaccharide components of MBF-GXUN74707 are mainly mannose (5.96 μg/mg), galactose (1.86 μg/mg), and glucose (1.73 μg/mg). Infrared spectrometric analysis showed the presence of carboxyl (COO-), hydroxyl (-OH) groups. The SEM images showed clumps of rod-shaped bacteria with adhesion of extracellular products. Furthermore, the strain decolored dye wastewater containing direct black, direct blue, and Congo red by 89.2%, 95.1%, 94.1%, respectively. The chemical oxygen demand (COD) and biological oxygen demand (BOD) removal rates after treatment of aquaculture wastewater with the fermentation broth were 68% and 23%, respectively. This study is the first to report the performance and application of strain in wastewater flocculation. The results indicate that strain is a good candidate for the production novel bioflocculants and demonstrates its potential industrial practicality in biotechnology processes.
PubMed: 38737412
DOI: 10.3389/fmicb.2024.1367043