How Nanotechniques Could Vitalize the O-GlcNAcylation-Targeting Approach for Cancer Therapy

Accumulated data indicated that many types of cancers have increased protein O-GlcNAcylation at cell surface and inside cells. The aberrant O-GlcNAcylation is considered a potential therapeutic target. Although several types of compounds capable of inhibiting O-GlcNAcylation have been developed, their low solubility, poor permeability and delivery efficiency have impeded the application for in vivo and pre-clinical studies. Nanocarriers have the advantages of controllable drug release and active cancer-targeting capability. Moreover, nanoparticles can improve drug delivery efficiency and reduce the non-specific distribution in normal tissues by the enhanced permeability and retention (EPR) effect in cancer. Taking the advantage of O-GlcNAc-specific antibodies or lectins, nanoparticles could further improve their cancer-targeting capability. Although nanocarriers targeting the canonical N- and O-linked glycosylation have been extensively investigated for cancer detection and therapy, application of nanotechniques for the specific targeting of O-GlcNAcylation has not been actively pursued. This review summarizes the general features of GlcNAcylation and its alterations in cancers. Analyses are focused on the following areas: How the nanocarriers may improve the solubility and/or cell permeability of O-GlcNAc transferase (OGT) inhibitors; The modification of nanocarriers with lectins or antibodies for active targeting of O-GlcNAc; The nanocarriers-mediated co-delivery of OGT inhibitors and conventional drugs, which may lead to synergistic effects. Unsolved issues impeding the research progression on O-GlcNAcylation-targeting scheme are also discussed.

A review of thermosensitive antinutritional factors in plant-based foods

Legumes and cereals account for the vast proportion of people's daily intake of plant-based foods. Meanwhile, a large number of antinutritional factors in legumes and cereals hinder the body absorption of nutrients and reduce the nutritional value of food. In this paper, the antinutritional effects, determination, and passivation methods of thermosensitive antinutritional factors such as trypsin inhibitors, urease, lipoxygenase, and lectin were reviewed to provide theoretical help to reduce antinutritional factors in food and improve the utilization rate of plant-based food nutrition. Since trypsin inhibitors and lectin have been more extensively studied and reviewed previously, the review mainly focused on urease and lipoxygenase. This review summarized the information of thermosensitive antinutritional factors, trypsin inhibitors, urease, lipoxygenase, and lectin, in cereals and legumes. The antinutritional effects, and physical and chemical properties of trypsin inhibitors, urease, lipoxygenase, and lectin were introduced. At the same time, the research methods for the detection and inactivation of these four antinutritional factors were also summarized in the order of research conducted time. The rapid determination and inactivation of antinutrients will be the focus of attention for the food industry in the future to improve the nutritional value of food. Exploring what structural changes could passivation technologies bring to antinutritional factors will provide a theoretical basis for further understanding the mechanisms of antinutritional factor inactivation. PRACTICAL APPLICATIONS: Antinutritional factors in plant-based foods hinder the absorption of nutrients and reduce the nutritional value of the food. Among them, thermosensitive antinutritional factors, such as trypsin inhibitors, urease, lipoxygenase, and lectins, have a high proportion among the antinutritional factors. In this paper, we investigate thermosensitive antinutritional factors from three perspectives: the antinutritional effect of thermosensitive antinutritional factors, determination, and passivation methods. The current passivation methods for thermosensitive antinutritional factors revolve around biological, physical, and chemical aspects, and their elimination mechanisms still need further research, especially at the protein structure level. Reducing the level of antinutritional factors in the future food industry while controlling the loss of other nutrients in food is a goal that needs to be balanced. This paper reviews the antinutritional effects of thermosensitive antinutritional factors and passivation methods, expecting to provide new research ideas to improve the nutrient utilization of food.

OBTAINING OF BIOLOGICALLY ACTIVE SUBSTANCES FROM AMARANTHUS CAUDATUS L. SEEDS IN ONE TECHNOLOGICAL CYCLE

Nowadays, amaranth is a valuable multi-purpose crop, a source of a number of very important biologically active substances. The aim of this study was to develop a comprehensive scheme for obtaining fatty oil, a sum of triterpenoids and a lectin from the seeds of Amaranthus caudatus L. in one technological cycle. Two variants of the lectin and the triterpene compounds purification from amaranth seeds were tested. It was determined that extracted of triterpene compounds should be carried out after purification of the lectin from degreased seeds. The rationality of this sequence of technological operations is explained by the lability of the lectin and insolubility in water triterpene compounds from amaranth seeds. The study also presents a scheme for obtaining squalene from amaranth oil by chromatography on silica gel and proposed a more effective affinity sorbent for purification of the lectin. The use of such sorbent also opens the possibility of preserving other water-soluble substances from amaranth seeds. Physicochemical characteristics and carbohydrate specificity of the lectin are described, new data on the results of interaction of the lectin with human and animal erythrocytes are given. The obtained results are discussed in the light of complex use of raw materials.

Quantification of Protein "Biomarkers" in Wheat-Based Food Systems: Dealing with Process-Related Issues

Selected food proteins may represent suitable markers for assessing either the presence/absence of specific food ingredients or the type and intensity of food processes. A fundamental step in the quantification of any protein marker is choosing a proper protocol for solubilizing the protein of interest. This step is particularly critical in the case of solid foods and when the protein analyte is prone to undergo intermolecular disulfide exchange reactions with itself or with other protein components in the system as a consequence of process-induced unfolding. In this frame, gluten-based systems represent matrices where a protein network is present and the biomarker proteins may be either linked to other components of the network or trapped into the network itself. The protein biomarkers considered here were wheat gluten toxic sequences for coeliac (QQPFP, R5), wheat germ agglutinin (WGA), and chicken egg ovalbumin (OVA). These proteins were considered here in the frame of three different cases dealing with processes different in nature and severity. Results from individual cases are commented as for: (1) the molecular basis of the observed behavior of the protein; (2) the design of procedure aimed at improving the recovery of the protein biomarker in a form suitable for reliable identification and quantification; (3) a critical analysis of the difficulties associated with the plain transfer of an analytical protocol from one product/process to another. Proper respect for the indications provided by the studies exemplified in this study may prevent coarse errors in assays and vane attempts at estimating the efficacy of a given treatment under a given set of conditions. The cases presented here also indicate that recovery of a protein analyte often does not depend in a linear fashion on the intensity of the applied treatment, so that caution must be exerted when attributing predictive value to the results of a particular study.

Moringa Oleifera Lam. in Cardiometabolic Disorders: A Systematic Review of Recent Studies and Possible Mechanism of Actions

Cardiometabolic disorders (CMD) have become a global emergency and increasing burden on health and economic problems. Due to the increasing need for new drugs for cardiometabolic diseases, many alternative medicines from plants have been considered and studied. Moringa oleifera Lam. (MO), one of the native plants from several Asian countries, has been used empirically by people for various kinds of illnesses. In the present systematic review, we aimed to investigate the recent studies of MO in CMD and its possible mechanism of action. We systematically searched from three databases and summarized the data. This review includes a total of 108 papers in nonclinical studies and clinical trials of MO in cardiometabolic-related disorders. Moringa oleifera, extracts or isolated compound, exerts its effect on CMD through its antioxidative, anti-inflammatory actions resulting in the modulation in glucose and lipid metabolism and the preservation of target organ damage. Several studies supported the beneficial effect of MO in regulating the gut microbiome, which generates the diversity of gut microbiota and reduces the number of harmful bacteria in the caecum. Molecular actions that have been studied include the suppression of NF-kB translocation, upregulation of the Nrf2/Keap1 pathway, stimulation of total antioxidant capacity by reducing PKCζ activation, and inhibiting the Nox4 protein expression and several other proposed mechanisms. The present review found substantial evidence supporting the potential benefits of Moringa oleifera in cardiovascular or metabolic disorders.

Forward Genetic Screens of Human Glycosylation Pathways Using the GlycoGene CRISPR Library

CRISPR-Cas9-based forward genetic screens represent a powerful discovery platform to uncover genes regulating specific biological processes. This article describes a method for utilizing a freely available GlycoGene CRISPR library to knock out any gene participating in human glycosylation in arbitrary cell types. The end product is a stable GlycoGene CRISPR knockout cell library, where each cell contains one or more sgRNA and lacks corresponding function. The cell library can be screened using various lectin/antibody reagents. It can also be applied in functional assays to establish glycan structure-glycogene-glycopathway relationships. This is a powerful systems glycobiology strategy for dissecting glycosylation pathways and processes. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Scale-up and NGS validation of the GlycoGene CRISPR plasmid library Basic Protocol 2: Preparation of a GlycoGene CRISPR lentivirus pool and an isogenic cell line stably expressing Cas9 nuclease Basic Protocol 3: Preparation of a GlycoGene CRISPR cell library, self-inactivation of Cas9, and library validation by NGS Basic Protocol 4: Enrichment of lectin-binding or non-binding cells and related multiplex NGS data acquisition Basic Protocol 5: Bioinformatics pathway analysis.

New Mutants of Epsilon Toxin from Clostridium perfringens with an Altered Receptor-Binding Site and Cell-Type Specificity

Epsilon toxin (Etx) from Clostridium perfringens is the third most potent toxin after the botulinum and tetanus toxins. Etx is the main agent of enterotoxemia in ruminants and is produced by Clostridium perfringens toxinotypes B and D, causing great economic losses. Etx selectively binds to target cells, oligomerizes and inserts into the plasma membrane, and forms pores. A series of mutants have been previously generated to understand the cellular and molecular mechanisms of the toxin and to obtain valid molecular tools for effective vaccination protocols. Here, two new non-toxic Etx mutants were generated by selective deletions in the binding (Etx-ΔS188-F196) or insertion (Etx-ΔV108-F135) domains of the toxin. As expected, our results showed that Etx-ΔS188-F196 did not exhibit the usual Etx binding pattern but surprisingly recognized specifically an O-glycoprotein present in the proximal tubules of the kidneys in a wide range of animals, including ruminants. Although diminished, Etx-ΔV108-F135 maintained the capacity for binding and even oligomerization, indicating that the mutation particularly affected the pore-forming ability of the toxin.

Pathogenic Leptospira Evolved a Unique Gene Family Comprised of Ricin B-Like Lectin Domain-Containing Cytotoxins

Leptospirosis is a globally important neglected zoonotic disease. Previous data suggest that a family of virulence-modifying (VM) proteins (PF07598) is a distinctive feature of group I pathogenic Leptospira that evolved as important virulence determinants. Here, we show that one such VM protein, LA3490 (also known as Q8F0K3), is expressed by Leptospira interrogans serovar Lai, as a secreted genotoxin that is potently cytotoxic to human cells. Structural homology searches using Phyre2 suggested that VM proteins are novel R-type lectins containing tandem N-terminal ricin B-chain-like β-trefoil domains. Recombinant LA3490 (rLA3490) and an N-terminal fragment, t3490, containing only the predicted ricin B domain, bound to the terminal galactose and N-acetyl-galactosamine residues, asialofetuin, and directly competed for asialofetuin-binding sites with recombinant ricin B chain. t3490 alone was sufficient for binding, both to immobilized asialofetuin and to the HeLa cell surface but was neither internalized nor cytotoxic. Treatment of HeLa cells with rLA3490 led to cytoskeleton disassembly, caspase-3 activation, and nuclear fragmentation, and was rapidly cytolethal. rLA3490 had DNase activity on mammalian and bacterial plasmid DNA. The combination of cell surface binding, internalization, nuclear translocation, and DNase functions indicate that LA3490 and other VM proteins evolved as novel forms of the bacterial AB domain-containing toxin paradigm.

The S1 Subunit of the SARS-CoV-2 Spike Protein Activates Human Monocytes to Produce Cytokines Linked to COVID-19: Relevance to Galectin-3

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), rapidly evolved into a pandemic –the likes of which has not been experienced in 100 years. While novel vaccines show great efficacy, and therapeutics continue to be developed, the persistence of disease, with the concomitant threat of emergent variants, continues to impose massive health and socioeconomic issues worldwide. Studies show that in susceptible individuals, SARS-CoV-2 infection can rapidly progress toward lung injury and acute respiratory distress syndrome (ARDS), with evidence for an underlying dysregulated innate immune response or cytokine release syndrome (CRS). The mechanisms responsible for this CRS remain poorly understood, yet hyper-inflammatory features were also evident with predecessor viruses within the β-coronaviridae family, namely SARS-CoV-1 and the Middle East Respiratory Syndrome (MERS)-CoV. It is further known that the spike protein (S) of SARS-CoV-2 (as first reported for other β-coronaviruses) possesses a so-called galectin-fold within the N-terminal domain of the S1 subunit (S1-NTD). This fold (or pocket) shows structural homology nearly identical to that of human galectin-3 (Gal-3). In this respect, we have recently shown that Gal-3, when associated with epithelial cells or anchored to a solid phase matrix, facilitates the activation of innate immune cells, including basophils, DC, and monocytes. A synthesis of these findings prompted us to test whether segments of the SARS-CoV-2 spike protein might also activate innate immune cells in a manner similar to that observed in our Gal-3 studies. Indeed, by immobilizing S components onto microtiter wells, we show that only the S1 subunit (with the NTD) activates human monocytes to produce a near identical pattern of cytokines as those reported in COVID-19-related CRS. In contrast, both the S1-CTD/RBD, which binds ACE2, and the S2 subunit (stalk), failed to mediate the same effect. Overall, these findings provide evidence that the SARS-CoV-2 spike protein can activate monocytes for cytokines central to COVID-19, thus providing insight into the innate immune mechanisms underlying the CRS and the potential for therapeutic interventions.

Glycosylation-Dependent Induction of Programmed Cell Death in Murine Adenocarcinoma Cells

Altered surface glycosylation is a major hallmark of tumor cells associated with aggressive phenotype and poor prognosis. By recognizing specific carbohydrate motifs, lectins can be applied to distinguish tumor from healthy cells based on the expression of glycosylation-dependent markers. Through their ability to bind to specific carbohydrates, lectins induce cell agglutination and cross-link surface glycoproteins, thereby mediating mitogenic and death-inducing effects in various cell types. The carbohydrate-selective cytotoxic effect of lectins also enables their possible application in therapies targeting cancer cells. To clarify the intracellular pathways mediating cell death induced by a group of plant and fungal lectins, we investigated mouse adenocarcinoma MC-38 cells harboring inactive genes involved in apoptosis, necroptosis and pyroptosis. Treatment of MC-38 cells with wheat germ agglutinin, Maackia amurensis lectin I, and Aleuria aurantia lectin induced multiple cell death pathways through reactions that relied on the autophagy machinery without depending on caspase activation. Furthermore, inhibition of de novo protein synthesis by cycloheximide strongly decreased the cytotoxic response, indicating that the lectins investigated induced cell death via effector molecules that are not expressed under normal circumstances and supporting the non-apoptotic nature of cell death. The broad cytotoxic response to lectins can be beneficial for the development of combination therapies targeting tumor cells. Given that tumors acquire resistance to various cytotoxic treatments because of mutations in cell death pathways, compounds inducing broad cytotoxic responses, such as lectins, represent potent sensitizers to promote tumor cell killing.

Vascular E-selectin Expression Detected in Formalin-fixed, Paraffin-embedded Sections With an E-selectin Monoclonal Antibody Correlates With Ulcerative Colitis Activity

It is widely accepted that E-selectin, an inducible endothelial cell adhesion molecule, plays a critical role in the initial step of neutrophil recruitment to sites of acute inflammation. However, immunohistological analysis of E-selectin has been hampered by lack of E-selectin-specific monoclonal antibodies that can stain formalin-fixed, paraffin-embedded (FFPE) tissue sections. Here, we employed E-selectin•IgM (a soluble form of E-selectin) as immunogen, and then, after negative selection with L-selectin•IgM and P-selectin•IgM and screening of FFPE sections of both COS-1 cells overexpressing E-selectin and acute appendicitis tissues, we successfully generated an E-selectin-specific monoclonal antibody capable of staining FFPE tissue sections. We used this antibody, designated U12-12, to perform quantitative immunohistological analysis of 390 colonic mucosal biopsy specimens representing ulcerative colitis. We found that the higher the histological disease activity, the greater the number of vessels expressing E-selectin, an observation consistent with previous analyses of frozen tissue sections. Furthermore, in active ulcerative colitis, E-selectin-expressing vessels contained neutrophils attached to endothelial cells, presumably in the process of extravasation, which eventually could cause epithelial damage. These results overall indicate that U12-12 is effective for E-selectin immunohistochemistry in archived FFPE samples representing various human diseases.

Site-specific N-glycan profiles of α5 β1 integrin from rat liver

BACKGROUND INFORMATION

Like most other cell surface proteins, α₅ β₁ integrin is glycosylated, which is required for its various activities in ways that mostly remain to be determined.

RESULTS

Here, we have established the first comprehensive site-specific glycan map of α₅ β₁ integrin that was purified from a natural source, i.e., rat liver. This analysis revealed striking site selective variations in glycan composition. Complex bi, tri or tetraantennary N-glycans were predominant at various proportions at most potential N-glycosylation sites. A few of these sites were non-glycosylated or contained high mannose or hybrid glycans, indicating that early N-glycan processing was hindered. Almost all complex N-glycans had fully galactosylated and sialylated antennae. Moderate levels of core fucosylation and high levels of O-acetylation of NeuAc residues were observed at certain sites. An O-linked HexNAc was found in an EGF-like domain of β₁ integrin. The extensive glycan information that results from our study was projected onto a map of α₅ β₁ integrin that was obtained by homology modeling. We have used this model for the discussion of how glycosylation might be used in the functional cycle of α₅ β₁ integrin. A striking example concerns the involvement of glycan-binding galectins in the regulation of the molecular homeostasis of glycoproteins at the cell surface through the formation of lattices or endocytic pits according to the glycolipid-lectin (GL-Lect) hypothesis.

CONCLUSION

We expect that the glycoproteomics data of the current study will serve as a resource for the exploration of structural mechanisms by which glycans control α₅ β₁ integrin activity and endocytic trafficking.

SIGNIFICANCE

Glycosylation of α₅ β₁ integrin has been implicated in multiple aspects of integrin function and structure. Yet, detailed knowledge of its glycosylation, notably the specific sites of glycosylation, is lacking. Furthermore, the α₅ β₁ integrin preparation that was analyzed here is from a natural source, which is of importance as there is not a lot of literature in the field about the glycosylation of 'native' glycoproteins. This article is protected by copyright. All rights reserved.

The Human Liver-Expressed Lectin CD302 Restricts Hepatitis C Virus Infection

C-type lectin domain-containing proteins (CTLDcps) shape host responses to pathogens and infectious disease outcomes. Previously, we identified the murine CTLDcp Cd302 as restriction factor, limiting hepatitis C virus (HCV) infection of murine hepatocytes. In this study, we investigated in detail the human orthologue's ability to restrict HCV infection in human liver cells. CD302 overexpression in Huh-7.5 cells potently inhibited infection of diverse HCV chimeras representing seven genotypes. Transcriptional profiling revealed abundant CD302 mRNA expression in human hepatocytes, the natural cellular target of HCV. Knockdown of endogenously expressed CD302 modestly enhanced HCV infection of Huh-7.5 cells and primary human hepatocytes. Functional analysis of naturally occurring CD302 transcript variants and engineered CD302 mutants showed that the C-type lectin-like domain (CTLD) is essential for HCV restriction, whereas the cytoplasmic domain (CPD) is dispensable. Coding single nucleotide polymorphisms occurring in human populations and mapping to different domains of CD302 did not influence the capacity of CD302 to restrict HCV. Assessment of the anti-HCV phenotype at different life cycle stages indicated that CD302 preferentially targets the viral entry step. In contrast to the murine orthologue, overexpression of human CD302 did not modulate downstream expression of nuclear receptor-controlled genes. Ectopic CD302 expression restricted infection of liver tropic hepatitis E virus (HEV), while it did not affect infection rates of two respiratory viruses, including respiratory syncytial virus (RSV) and the alpha coronavirus HVCoV-229E. Together, these findings suggest that CD302 contributes to liver cell-intrinsic defense against HCV and might mediate broader antiviral defenses against additional hepatotropic viruses. IMPORTANCE The liver represents an immunoprivileged organ characterized by enhanced resistance to immune responses. However, the importance of liver cell-endogenous, noncytolytic innate immune responses in pathogen control is not well defined. Although the role of myeloid cell-expressed CTLDcps in host responses to viruses has been characterized in detail, we have little information about their potential functions in the liver and their relevance for immune responses in this organ. Human hepatocytes endogenously express the CTLDcp CD302. Here, we provide evidence that CD302 limits HCV infection of human liver cells, likely by inhibiting a viral cell entry step. We confirm that the dominant liver-expressed transcript variant, as well as naturally occurring coding variants of CD302, maintain the capacity to restrict HCV. We further show that the CTLD of the protein is critical for the anti-HCV activity and that overexpressed CD302 limits HEV infection. Thus, CD302 likely contributes to human liver-intrinsic antiviral defenses.

The fungal Clitocybe nebularis lectin binds distinct cell surface glycoprotein receptors to induce cell death selectively in Jurkat cells

Clitocybe nebularis lectin (CNL) is a GalNAcβ1-4GlcNAc-binding lectin that exhibits an antiproliferative effect exclusively on the Jurkat leukemic T cell line by provoking homotypic aggregation and dose-dependent cell death. Cell death of Jurkat cells exhibited typical features of early apoptosis, but lacked the activation of initiating and executing caspases. None of the features of CNL-induced cell death were effectively blocked with the pan-caspase inhibitor or different cysteine peptidase inhibitors. Furthermore, CNL binding induced Jurkat cells to release the endogenous damage-associated molecular pattern molecule high-mobility group box 1 (HMGB1). A plant lectin with similar glycan-binding specificity, Wisteria floribunda agglutinin (WFA) showed less selective toxicity and induced cell death in Jurkat, Tall-104, and Hut-87 cell lines. HMGB1 release was also detected when Jurkat cells were treated with WFA. We identified the CD45 and CD43 cell surface glycoproteins on Jurkat cells as the main targets for CNL binding. However, the blockade of CD45 phosphatase activity failed to block either CNL-induced homotypic agglutination or cell death. Overall, our results indicate that CNL triggers atypical cell death selectively on Jurkat cells, suggesting the potential applicability of CNL in novel strategies for treating and/or detecting acute T cell leukemia.

Investigation of the Molecular Details of the Interactions of Selenoglycosides and Human Galectin-3

Human galectin-3 (hGal-3) is involved in a variety of biological processes and is implicated in wide range of diseases. As a result, targeting hGal-3 for clinical applications has become an intense area of research. As a step towards the development of novel hGal-3 inhibitors, we describe a study of the binding of two Se-containing hGal-3 inhibitors, specifically that of di(β-D-galactopyranosyl)selenide (SeDG), in which two galactose rings are linked by one Se atom and a di(β-D-galactopyranosyl)diselenide (DSeDG) analogue with a diseleno bond between the two sugar units. The binding affinities of these derivatives to hGal-3 were determined by ¹⁵N-¹H HSQC NMR spectroscopy and fluorescence anisotropy titrations in solution, indicating a slight decrease in the strength of interaction for SeDG compared to thiodigalactoside (TDG), a well-known inhibitor of hGal-3, while DSeDG displayed a much weaker interaction strength. NMR and FA measurements showed that both seleno derivatives bind to the canonical S face site of hGal-3 and stack against the conserved W181 residue also confirmed by X-ray crystallography, revealing canonical properties of the interaction. The interaction with DSeDG revealed two distinct binding modes in the crystal structure which are in fast exchange on the NMR time scale in solution, explaining a weaker interaction with hGal-3 than SeDG. Using molecular dynamics simulations, we have found that energetic contributions to the binding enthalpies mainly differ in the electrostatic interactions and in polar solvation terms and are responsible for weaker binding of DSeDG compared to SeDG. Selenium-containing carbohydrate inhibitors of hGal-3 showing canonical binding modes offer the potential of becoming novel hydrolytically stable scaffolds for a new class of hGal-3 inhibitors.

Human intelectin-2 (ITLN2) is selectively expressed by secretory Paneth cells

Intelectins (intestinal lectins) are highly conserved across chordate evolution and have been implicated in various human diseases, including Crohn's disease (CD). The human genome encodes two intelectin genes, intelectin-1 (ITLN1) and intelectin-2 (ITLN2). Other than its high sequence similarity with ITLN1, little is known about ITLN2. To address this void in knowledge, we report that ITLN2 exhibits discrete, yet notable differences from ITLN1 in primary structure, including a unique amino terminus, as well as changes in amino acid residues associated with the glycan-binding activity of ITLN1. We identified that ITLN2 is a highly abundant Paneth cell-specific product, which localizes to secretory granules, and is expressed as a multimeric protein in the small intestine. In surgical specimens of ileal CD, ITLN2 mRNA levels were reduced approximately five-fold compared to control specimens. The ileal expression of ITLN2 was unaffected by previously reported disease-associated variants in ITLN2 and CD-associated variants in neighboring ITLN1 as well as NOD2 and ATG16L1. ITLN2 mRNA expression was undetectable in control colon tissue; however, in both ulcerative colitis (UC) and colonic CD, metaplastic Paneth cells were found to express ITLN2. Together, the data reported establish the groundwork for understanding ITLN2 function(s) in the intestine, including its possible role in CD.

Functional Microfiber Nonwoven Fabric with Sialic Acid-Immobilized Polymer Brush for Capturing Lectin in Aerosol

The influenza virus has been known as a representative infectious virus that harms human health from the past to the present day. We have promoted the development of a novel adsorbent capable of adsorbing influenza viruses in the form of aerosols in the air. In this study, to develop a material to adsorb the influenza virus, a functional group was introduced into a microfiber nonwoven fabric (MNWF) manufactured through radiation-induced graft polymerization (RIGP), and sialic acid was immobilized to mimic the sugar chain cluster effect. The functional group was used by coupling disodium iminodiacetate monohydrate (IDA) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC), and N-acetylneuraminic acid (NANA) was selected for sialic acid. IDA-EDC was introduced into GMA MNWF with an average molar conversion of 47%. For NANA MNWF with a degree of grafting (dg) of 87% introduced with sialic acid, 118.2 of 200 µg of aerosolized lectin was adsorbed, confirming that the maximum adsorption amount was 59.1%. In NANA MNWF of 100% or more dg, a tendency to decrease the amount of lectin adsorption was observed compared to NANA MNWF of 80–100% dg.

Systemic Lectin-Glycan Interaction of Pathogenic Enteric Bacteria in the Gastrointestinal Tract

Microorganisms, such as bacteria, viruses, and fungi, and host cells, such as plants and animals, have carbohydrate chains and lectins that reciprocally recognize one another. In hosts, the defense system is activated upon non-self-pattern recognition of microbial pathogen-associated molecular patterns. These are present in Gram-negative and Gram-positive bacteria and fungi. Glycan-based PAMPs are bound to a class of lectins that are widely distributed among eukaryotes. The first step of bacterial infection in humans is the adhesion of the pathogen's lectin-like proteins to the outer membrane surfaces of host cells, which are composed of glycans. Microbes and hosts binding to each other specifically is of critical importance. The adhesion factors used between pathogens and hosts remain unknown; therefore, research is needed to identify these factors to prevent intestinal infection or treat it in its early stages. This review aims to present a vision for the prevention and treatment of infectious diseases by identifying the role of the host glycans in the immune response against pathogenic intestinal bacteria through studies on the lectin-glycan interaction.

Decoding Single Cell Morphology in Osteotropic Breast Cancer Cells for Dissecting Their Migratory, Molecular and Biophysical Heterogeneity

Breast cancer is a heterogeneous disease and the mechanistic framework for differential osteotropism among intrinsic breast cancer subtypes is unknown. Hypothesizing that cell morphology could be an integrated readout for the functional state of a cancer cell, we established a catalogue of the migratory, molecular and biophysical traits of MDA-MB-231 breast cancer cells, compared it with two enhanced bone-seeking derivative cell lines and integrated these findings with single cell morphology profiles. Such knowledge could be essential for predicting metastatic capacities in breast cancer. High-resolution microscopy revealed a heterogeneous and specific spectrum of single cell morphologies in bone-seeking cells, which correlated with differential migration and stiffness. While parental MDA-MB-231 cells showed long and dynamic membrane protrusions and were enriched in motile cells with continuous and mesenchymal cell migration, bone-seeking cells appeared with discontinuous mesenchymal or amoeboid-like migration. Although non-responsive to CXCL12, bone-seeking cells responded to epidermal growth factor with a morphotype shift and differential expression of genes controlling cell shape and directional migration. Hence, single cell morphology encodes the molecular, migratory and biophysical architecture of breast cancer cells and is specifically altered among osteotropic phenotypes. Quantitative morpho-profiling could aid in dissecting breast cancer heterogeneity and in refining clinically relevant intrinsic breast cancer subtypes.

77Se-Enriched Selenoglycoside Enables Significant Enhancement in NMR Spectroscopic Monitoring of Glycan-Protein Interactions

Detailed investigation of ligand-protein interactions is essential for better understanding of biological processes at the molecular level. Among these binding interactions, the recognition of glycans by lectins is of particular importance in several diseases, such as cancer; therefore, inhibition of glycan-lectin/galectin interactions represents a promising perspective towards developing therapeutics controlling cancer development. The recent introduction of 77Se NMR spectroscopy for monitoring the binding of a selenoglycoside to galectins prompted interest to optimize the sensitivity by increasing the 77Se content from the natural 7.63% abundance to 99%. Here, we report a convenient synthesis of 77Se-enriched selenodigalactoside (SeDG), which is a potent ligand of the medically relevant human galectin-3 protein, and proof of the expected sensitivity gain in 2D 1H, 77Se correlation NMR experiments. Our work opens perspectives for adding isotopically enriched selenoglycans for rapid monitoring of lectin-binding of selenated as well as non-selenated ligands and for ligand screening in competition experiments.

Engineering the ligand specificity of the human galectin-1 by incorporation of tryptophan analogs

Galectin-1 is a β-galactoside-binding lectin with manifold biological functions. A single tryptophan residue (W68) in its carbohydrate binding site plays a major role in ligand binding and is highly conserved among galectins. To fine tune galectin-1 specificity, we introduced several non-canonical tryptophan analogs at this position of human galectin-1 and analyzed the resulting variants using glycan microarrays. Two variants containing 7-azatryptophan and 7-fluorotryptophan showed a reduced affinity for 3'-sulfated oligosaccharides. Their interaction with different ligands was further analyzed by fluorescence polarization competition assay. Using molecular modeling we provide structural clues that the change in affinities comes from modulated interactions and solvation patterns. Thus, we show that the introduction of subtle atomic mutations in the ligand binding site of galectin-1 is an attractive approach for fine-tuning its interactions with different ligands.

Inherited defects in the complement system

The complement system plays an essential role in both innate and adaptive immune responses. Any dysregulation in this system can disturb normal host defense and alter inflammatory response leading to both infections and autoimmune diseases. The complement system can be activated through three different pathways. Inherited complement deficiencies have been described for all complement components and their regulators. Despite being rare diseases, complement deficiencies are often severe, with a frequent onset during childhood. We provide an overview of clinical disorders related to these disorders and describe current diagnostic strategies required for their comprehensive characterization and management.

Design of novel cyanovirin-N variants by modulation of binding dynamics through distal mutations

We develop integrated co-evolution and dynamic coupling (ICDC) approach to identify, mutate, and assess distal sites to modulate function. We validate the approach first by analyzing the existing mutational fitness data of TEM-1 β-lactamase and show that allosteric positions co-evolved and dynamically coupled with the active site significantly modulate function. We further apply ICDC approach to identify positions and their mutations that can modulate binding affinity in a lectin, cyanovirin-N (CV-N), that selectively binds to dimannose, and predict binding energies of its variants through Adaptive BP-Dock. Computational and experimental analyses reveal that binding enhancing mutants identified by ICDC impact the dynamics of the binding pocket, and show that rigidification of the binding residues compensates for the entropic cost of binding. This work suggests a mechanism by which distal mutations modulate function through dynamic allostery and provides a blueprint to identify candidates for mutagenesis in order to optimize protein function.

Lectin Staining to Detect Human and Avian Influenza Virus Receptors in the Airway of Nonhuman Primates

Hemagglutinin (HA) on the surface of influenza viruses binds to sialic acids, mainly N-acetylneuraminic acid (Neu5Ac) or N-glycolylneuraminic acid. Neu5Ac and N-glycolylneuraminic acid lie at the terminal end of sugar chains on the cell surface. Human influenza viruses preferentially bind to sialic acids bound to galactose by the alpha2-6 linkage (Neu5Acα2-6Gal), abundant in the human airway. In contrast, avian influenza viruses preferentially bind to Neu5Acα2-3Gal, abundant in the intestine of ducks. Sambucus nigra lectin (SNA) and Maackia amurensis lectin (MAA) bind to Neu5Acα2-6Gal and Neu5Acα2-3Gal, respectively. These two lectins have therefore been applied to detect sialic acids on the airway epithelium of animals.

Purification, Partial Characterization, and Evaluation of the Antiulcer Activity of Calotropis procera Leaf Lectin

BACKGROUND

Lectins are proteins with therapeutic and diagnostic potential that can be applied in battling various ailments.

AIM AND OBJECTIVE

This study was designed to purify and characterize the hemagglutinating activity derived from the leaves of Calotropis procera and its possible role in protecting the stomach against ethanol-induced lesions.

METHODS

The Calotropis procera leaf lectin (ProLec), was isolated by homogenization of the defatted leaf powder in Phosphate-Buffered Saline (PBS) and purified by affinity chromatography on Sephadex G-100. The lectin was eluted from the affinity column by 3% acetic acid and was physicochemically characterized. In a dose-dependent manner, ProLec was administered to rats with ethanol-induced ulcers, and biochemical, histopathological, and toxicological examinations were performed.

RESULTS

ProLec is a heterodimer of 75 and 68 kDa. It agglutinated all human RBCs, whereas it showed weak interaction with animal erythrocytes. The protein was optimally active at 25 °C and was labile above this temperature. ProLec exhibited two pH optima and was a metalloprotein requiring Ca, Mn, and Ni. It contains 1.6% tryptophan residues of which about 1% is exposed and critical for lectin activity. The lectin exhibited a potent gastroprotective effect against ethanolinduced gastric lesions with no apparent toxicity to both kidneys and liver. Examination of the pH of the gastric juice of lectin-treated animals indicated a possible role of lectin in maintaining stomach acidity within the normal ranges compared to the gastric juice pH of animals that received ethanol only.

CONCLUSION

These results may suggest that ProLec could conceivably be a good future drug for the treatment of gastric ulcers, however, extensive immunological and toxicological research remains to be done.